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Sample records for chemo-mechanical coupling behaviour

  1. Physico-chemo-mechanical coupling mechanisms in soil behavior

    NASA Astrophysics Data System (ADS)

    Hu, Liangbo

    Many processes in geomechanics or geotechnical/geomechanical system engineering involve phenomena that are physical and/or chemical in nature, the understanding of which is crucial to modeling the mechanical responses of soils to various loads. Such physico-chemo-mechanical coupling mechanisms are prevalent in two different types of geomechanical processes studied in this dissertation: long-term soil/sediments compaction & desiccation cracking. Most commonly the underlying physical and chemical phenomena are explained, formulated and quantified at microscopic level. In addition to the necessity of capturing the coupling mechanisms, another common thread that emerges in formulating their respective mathematical model is the necessity of linking phenomena occurring at different scales with a theory to be formulated at a macroscopic continuum level. Part I of this dissertation is focused on the subject of long-term compaction behavior of soils and sediments. The interest in this subject arises from the need to evaluate reservoir compaction and land subsidence that may result from oil/gas extraction in petroleum engineering. First, a damage-enhanced reactive chemo-plasticity model is developed to simulate creep of saturated geomaterials, a long-term strain developed at constant stress. Both open and closed systems are studied. The deformation at a constant load in a closed system exhibits most of the characteristics of the classical creep. Primary, secondary and tertiary creep can be interpreted in terms of dominant mechanisms in each phase, emphasizing the role of the rates of dissolution and precipitation, variable reaction areas and chemical softening intensity. The rest of Part I is devoted to the study of soil aging, an effect of a localized mineral dissolution related creep strain and subsequent material stiffening. A three-scale mathematical model is developed to numerically simulate the scenarios proposed based on macroscopic experiments and geochemical

  2. Entrapment in giant polymersomes of an inorganic oscillatory chemical reaction and resulting chemo-mechanical coupling.

    PubMed

    Pereira de Souza, Tereza; Perez-Mercader, Juan

    2014-08-18

    We present a methodology to entrap and run the Belousov-Zhabotinsky (BZ) reaction inside a polymer vesicle. We report on experiments with polymer vesicles where we observed (1) vesicle membrane deformations, (2) oscillations and (3) pulsating (expansion/contraction) episodes. The above provide us with evidence for chemo-mechanical coupling between these polymersomes and their contents. PMID:24977662

  3. chemo-mechanical coupling in water unsaturated domains: capillary tension and crystallization pressure

    NASA Astrophysics Data System (ADS)

    Hulin, Claudie; Mercury, Lionel

    2015-04-01

    Unsaturated zones are widely present in natural systems, such as soils, deep aquifers and building stones under wetting-drying cycles. Such porous media contains the three phases liquid, gas and solid and present specific physico-chemical processes or properties - as soluble salts precipitation or capillary water properties rise - have important impact on environmental issues since they are coupled with mechanical effects. The driving force of both phase transitions and capillarization is the decreasing relative humidity below the saturated value in the atmospheric air contacting the unsaturated materials. - Decreasing relative humidity leads to evaporation, creating local supersaturation and then driving crystallization. According to the usual theory of crystallization pressure, a confined growing crystal can exert a constraint against the pore wall, leading to its rupture if it exceeds the tensile strength of the pore material. This coupled chemo-mechanical process requires a nano-scale film of solution to hold between the crystal and the pore, which allows the solutes to diffuse and the solution not to precipitate despite increasing supersaturation. The repulsive effect between growing and host solids, ultimately increases the local pressure and may induce the host rupture - Capillarity has a large occurrence in unsaturated porous media and depends on pore radius and relative humidity of air. The capillary state makes the internal pressure of capillary water can drop down to negative values, meaning it is under tensile state and potentially exert traction on pore wall. These effects of chemo-mechanical coupling are observed using an experimental approach on three simplified natural analogues: porous membrane, borosilicate microcapillaries, and synthetic fluid inclusions. In the two former samples, sodium sulfates precipitates are induced through wetting-drying cycles and the role of both the capillarity and the crystallization pressure are observed. In the

  4. Modelling and simulations of the chemo-mechanical behaviour of leached cement-based materials: Interactions between damage and leaching

    SciTech Connect

    Stora, E.; Bary, B.; Deville, E.; Montarnal, P.

    2010-08-15

    The assessment of the durability of cement-based materials, which could be employed in underground structures for nuclear waste disposal, requires accounting for deterioration factors, such as chemical attacks and damage, and for the interactions between these phenomena. The objective of the present paper consists in investigating the long-term behaviour of cementitious materials by simulating their response to chemical and mechanical solicitations. In a companion paper (Stora et al., submitted to Cem. Concr. Res. 2008), the implementation of a multi-scale homogenization model into an integration platform has allowed for evaluating the evolution of the mineral composition, diffusive and elastic properties inside a concrete material subjected to leaching. To complete this previous work, an orthotropic micromechanical damage model is presently developed and incorporated in this numerical platform to estimate the mechanical and diffusive properties of damaged cement-based materials. Simulations of the chemo-mechanical behaviour of leached cementitious materials are performed with the tool thus obtained and compared with available experiments. The numerical results are insightful about the interactions between damage and chemical deteriorations.

  5. Investigation of the chemo-mechanical coupling in lithiation/delithiation of amorphous Si through simulations of Si thin films and Si nanospheres

    NASA Astrophysics Data System (ADS)

    Wang, Miao; Xiao, Xinran

    2016-09-01

    A strong asymmetric rate behavior between lithiation and delithiation has been observed in amorphous Si (a-Si) anode in the form of thin films, but not in other geometries, such as Si nanospheres. This work investigated the rate behavior of the two geometries through numerical simulations. The results reveal that the rate behavior is affected by the geometry and the constraint of the electrode, the chemo-mechanical coupling, and the prior process. A substrate-constrained film has a relatively low surface/volume ratio and a constant surface area. Its lithiation has a great tendency to be hindered by surface limitation. The chemo-mechanical coupling also plays an important role. The stress profiles differ in the two geometries but both affect the lithiation process more than the delithiation process. The overall delithiation capacity is affected very little by the chemo-mechanical coupling. In cyclic loading, the delithiation capacity is reduced at the same rate as the lithiation capacity because of the low initial state of charge in the electrode. The asymmetric rate behavior was absent under cyclic loading. On the other hand, a slow charging process resulted in a better retained delithiation capacity and an asymmetric rate behavior at higher rates.

  6. Time-dependent Deformation in Porous Rocks Driven by Chemo-mechanical Coupling

    NASA Astrophysics Data System (ADS)

    Meredith, P. G.; Brantut, N.; Heap, M. J.; Baud, P.

    2015-12-01

    We report results from triaxial deformation of porous sandstone and limestone conducted to determine the time-dependency of deformation. Experiments were run on water-saturated samples under constant differential stress (creep) conditions. In sandstone, the deformation is entirely brittle for all levels of stress and for all resulting strain rates. The strain rate during creep is very stress sensitive, with a change of only 20 MPa in differential stress producing three orders of magnitude change in strain rate. Failure occurs by localized shear faulting after an extended period of dilatant microcracking, as evidenced by the output of acoustic emissions. By contrast, the behaviour of limestone is more complex. At low effective pressure, the creep behavior is brittle and characterised by the same features as observed for sandstone; a decelerating phase of creep, followed by an inflection and then an accelerating creep phase leading to macroscopic failure. Similarly, only a small amount of inelastic strain is accommodated before failure, and P wave speeds measured throughout deformation decrease continuously, indicating a continuous increase in dilatant crack damage. At higher effective pressure, brittle creep still occurs, but the details of the time-dependent deformation behavior are quite different. First, the total amount of accumulated creep strain increases dramatically with decreasing strain rate, and no localized failure occurs even at these higher strains. Second, the rate of decrease in P wave speeds during deformation decreases with decreasing strain rate; indicating that less damage is accumulated per unit strain when the strain rate is lower. Third, complementary strain rate stepping experiments indicate that the deformation becomes more compactant at lower strain rates. Taken together, these observations suggest that rate-dependent compactive deformation mechanisms compete with dilatant subcritical crack growth during creep in limestone under low

  7. A chemo-mechanical constitutive model for transiently cross-linked actin networks and a theoretical assessment of their viscoelastic behaviour.

    PubMed

    Fallqvist, B; Kroon, M

    2013-04-01

    Biological materials can undergo large deformations and also show viscoelastic behaviour. One such material is the network of actin filaments found in biological cells, giving the cell much of its mechanical stiffness. A theory for predicting the relaxation behaviour of actin networks cross-linked with the cross-linker α-actinin is proposed. The constitutive model is based on a continuum approach involving a neo-Hookean material model, modified in terms of concentration of chemically activated cross-links. The chemical model builds on work done by Spiros (Doctoral thesis, University of British Columbia, Vancouver, Canada, 1998) and has been modified to respond to mechanical stress experienced by the network. The deformation is split into a viscous and elastic part, and a thermodynamically motivated rate equation is assigned for the evolution of viscous deformation. The model predictions were evaluated for stress relaxation tests at different levels of strain and found to be in good agreement with experimental results for actin networks cross-linked with α-actinin. PMID:22623110

  8. Tumour angiogenesis as a chemo-mechanical surface instability

    PubMed Central

    Giverso, Chiara; Ciarletta, Pasquale

    2016-01-01

    The hypoxic conditions within avascular solid tumours may trigger the secretion of chemical factors, which diffuse to the nearby vasculature and promote the formation of new vessels eventually joining the tumour. Mathematical models of this process, known as tumour angiogenesis, have mainly investigated the formation of the new capillary networks using reaction-diffusion equations. Since angiogenesis involves the growth dynamics of the endothelial cells sprouting, we propose in this work an alternative mechanistic approach, developing a surface growth model for studying capillary formation and network dynamics. The model takes into account the proliferation of endothelial cells on the pre-existing capillary surface, coupled with the bulk diffusion of the vascular endothelial growth factor (VEGF). The thermo-dynamical consistency is imposed by means of interfacial and bulk balance laws. Finite element simulations show that both the morphology and the dynamics of the sprouting vessels are controlled by the bulk diffusion of VEGF and the chemo-mechanical and geometric properties at the capillary interface. Similarly to dendritic growth processes, we suggest that the emergence of tree-like vessel structures during tumour angiogenesis may result from the free boundary instability driven by competition between chemical and mechanical phenomena occurring at different length-scales. PMID:26948692

  9. Tumour angiogenesis as a chemo-mechanical surface instability

    NASA Astrophysics Data System (ADS)

    Giverso, Chiara; Ciarletta, Pasquale

    2016-03-01

    The hypoxic conditions within avascular solid tumours may trigger the secretion of chemical factors, which diffuse to the nearby vasculature and promote the formation of new vessels eventually joining the tumour. Mathematical models of this process, known as tumour angiogenesis, have mainly investigated the formation of the new capillary networks using reaction-diffusion equations. Since angiogenesis involves the growth dynamics of the endothelial cells sprouting, we propose in this work an alternative mechanistic approach, developing a surface growth model for studying capillary formation and network dynamics. The model takes into account the proliferation of endothelial cells on the pre-existing capillary surface, coupled with the bulk diffusion of the vascular endothelial growth factor (VEGF). The thermo-dynamical consistency is imposed by means of interfacial and bulk balance laws. Finite element simulations show that both the morphology and the dynamics of the sprouting vessels are controlled by the bulk diffusion of VEGF and the chemo-mechanical and geometric properties at the capillary interface. Similarly to dendritic growth processes, we suggest that the emergence of tree-like vessel structures during tumour angiogenesis may result from the free boundary instability driven by competition between chemical and mechanical phenomena occurring at different length-scales.

  10. Bio-chemo-mechanical models for nuclear deformation in adherent eukaryotic cells.

    PubMed

    Nava, Michele M; Raimondi, Manuela T; Pietrabissa, Riccardo

    2014-10-01

    Adherent eukaryotic cells are subjected to a broad variety of extracellular and intracellular stimuli regulating their behaviour. These stimuli can be either purely chemical, for example soluble factors binding to the cell membrane, or mechano-chemical, for example integrin-based adhesion complexes stretching the cell cytoskeleton. Here, we focus on mechano-chemical stimuli such as extracellular forces (interstitial flow, pressurization) and intracellular forces (due to cell adhesion), which may combine generating stress-strain states in the cytoskeleton. These states are transferred to the nucleus to influence the transcription of specific genes, likely by changing the chromatin organization and by altering the permeability of the nuclear membrane. While there exists increasing experimental evidence of the mechanosensing role of the cell nucleus, both the underlying molecular mechanisms involved, and the nuclear structural behaviour in response to forces, are still poorly understood. Here, we review the existing literature on computational models developed to investigate the chemo-mechanical behaviour of adherent eukaryotic cells. We analyse two main classes of models of single-cell mechanics, based either on the discrete or on the continuum approaches. We focus on the bio-chemo-mechanical model and modelling techniques accounting for the nuclear body. The modelling techniques are discussed highlighting their ability in predicting cytoskeletal contractility states and nuclear stress-strain states.

  11. Bio-Chemo-Mechanical Models of Vascular Mechanics.

    PubMed

    Kim, Jungsil; Wagenseil, Jessica E

    2015-07-01

    Models of vascular mechanics are necessary to predict the response of an artery under a variety of loads, for complex geometries, and in pathological adaptation. Classic constitutive models for arteries are phenomenological and the fitted parameters are not associated with physical components of the wall. Recently, microstructurally-linked models have been developed that associate structural information about the wall components with tissue-level mechanics. Microstructurally-linked models are useful for correlating changes in specific components with pathological outcomes, so that targeted treatments may be developed to prevent or reverse the physical changes. However, most treatments, and many causes, of vascular disease have chemical components. Chemical signaling within cells, between cells, and between cells and matrix constituents affects the biology and mechanics of the arterial wall in the short- and long-term. Hence, bio-chemo-mechanical models that include chemical signaling are critical for robust models of vascular mechanics. This review summarizes bio-mechanical and bio-chemo-mechanical models with a focus on large elastic arteries. We provide applications of these models and challenges for future work.

  12. Chemo-mechanical control of neural stem cell differentiation

    NASA Astrophysics Data System (ADS)

    Geishecker, Emily R.

    Cellular processes such as adhesion, proliferation, and differentiation are controlled in part by cell interactions with the microenvironment. Cells can sense and respond to a variety of stimuli, including soluble and insoluble factors (such as proteins and small molecules) and externally applied mechanical stresses. Mechanical properties of the environment, such as substrate stiffness, have also been suggested to play an important role in cell processes. The roles of both biochemical and mechanical signaling in fate modification of stem cells have been explored independently. However, very few studies have been performed to study well-controlled chemo-mechanotransduction. The objective of this work is to design, synthesize, and characterize a chemo-mechanical substrate to encourage neuronal differentiation of C17.2 neural stem cells. In Chapter 2, Polyacrylamide (PA) gels of varying stiffnesses are functionalized with differing amounts of whole collagen to investigate the role of protein concentration in combination with substrate stiffness. As expected, neurons on the softest substrate were more in number and neuronal morphology than those on stiffer substrates. Neurons appeared locally aligned with an expansive network of neurites. Additional experiments would allow for statistical analysis to determine if and how collagen density impacts C17.2 differentiation in combination with substrate stiffness. Due to difficulties associated with whole protein approaches, a similar platform was developed using mixed adhesive peptides, derived from fibronectin and laminin, and is presented in Chapter 3. The matrix elasticity and peptide concentration can be individually modulated to systematically probe the effects of chemo-mechanical signaling on differentiation of C17.2 cells. Polyacrylamide gel stiffness was confirmed using rheological techniques and found to support values published by Yeung et al. [1]. Cellular growth and differentiation were assessed by cell counts

  13. One-Pot dry chemo-mechanical deconstruction for bioethanol production from sugarcane bagasse.

    PubMed

    Sambusiti, C; Licari, A; Solhy, A; Aboulkas, A; Cacciaguerra, T; Barakat, A

    2015-04-01

    The aim of this study was the application of an innovative dry chemo-mechanical pretreatment using different mechanical stresses to produce bioethanol from sugarcane bagasse (SB). The effect of different milling methods on physicochemical composition, enzymatic hydrolysis, bioethanol production and energy efficiency was also evaluated. SB was pretreated with NaOH and H3PO4 at high materials concentration (5 kg/L). Results indicate that vibratory milling (VBM) was more effective in the reduction of particles size and cellulose crystallinity compared to centrifugal (CM) and ball (BM) milling. NaOH pretreatment coupling to BM and VBM was preferred to enhance glucose yields and bioethanol production, while CM consumed less energy compared to BM and VBM. Moreover, the highest energy efficiency (η=0.116 kg glucose/kWh) was obtained with NaOH-CM. Therefore, the combination of dry NaOH and CM appears the most suitable and interesting pretreatment for the production of bioethanol from SB.

  14. Semi-deterministic chemo-mechanical model of boundary lubrication.

    PubMed

    Andersson, Joel; Larsson, Roland; Almqvist, Andreas; Grahn, Mattias; Minami, Ichiro

    2012-01-01

    A model for tribofilm growth is developed. The model is used in combination with numerical contact mechanics tools to enable evaluation of the combined effects of chemistry and contact mechanics. The model is tuned with experimental data and is thereafter applied to rough surfaces. The growth of the tribofilm is evaluated for 3 different contact cases and short-term tribofilm growth behaviour is analyzed. The results show how tribofilms grow in patches. The model is expected to be used as a tool for analysis of the interaction between rough surfaces.

  15. Chemo-mechanical modeling of tumor growth in elastic epithelial tissue

    NASA Astrophysics Data System (ADS)

    Bratsun, Dmitry A.; Zakharov, Andrey P.; Pismen, Len

    2016-08-01

    We propose a multiscale chemo-mechanical model of the cancer tumor development in the epithelial tissue. The epithelium is represented by an elastic 2D array of polygonal cells with its own gene regulation dynamics. The model allows the simulation of the evolution of multiple cells interacting via the chemical signaling or mechanically induced strain. The algorithm includes the division and intercalation of cells as well as the transformation of normal cells into a cancerous state triggered by a local failure of the spatial synchronization of the cellular rhythms driven by transcription/translation processes. Both deterministic and stochastic descriptions of the system are given for chemical signaling. The transformation of cells means the modification of their respective parameters responsible for chemo-mechanical interactions. The simulations reproduce a distinct behavior of invasive and localized carcinoma. Generally, the model is designed in such a way that it can be readily modified to take account of any newly understood gene regulation processes and feedback mechanisms affecting chemo-mechanical properties of cells.

  16. Single-Molecule Chemo-Mechanical Spectroscopy Provides Structural Identity of Folding Intermediates.

    PubMed

    Motlagh, Hesam N; Toptygin, Dmitri; Kaiser, Christian M; Hilser, Vincent J

    2016-03-29

    Single-molecule force spectroscopy has emerged as a powerful tool for studying the folding of biological macromolecules. Mechanical manipulation has revealed a wealth of mechanistic information on transient and intermediate states. To date, the majority of state assignment of intermediates has relied on empirical demarcation. However, performing such experiments in the presence of different osmolytes provides an alternative approach that reports on the structural properties of intermediates. Here, we analyze the folding and unfolding of T4 lysozyme with optical tweezers under a chemo-mechanical perturbation by adding osmolytes. We find that two unrelated protective osmolytes, sorbitol and trimethylamine-n-oxide, function by marginally decelerating unfolding rates and specifically modulating early events in the folding process, stabilizing formation of an on-pathway intermediate. The chemo-mechanical perturbation provides access to two independent metrics of the relevant states during folding trajectories, the contour length, and the solvent-accessible surface area. We demonstrate that the dependence of the population of the intermediate in different osmolytes, in conjunction with its measured contour length, provides the ability to discriminate between potential structural models of intermediate states. Our study represents a general strategy that may be employed in the structural modeling of equilibrium intermediate states observed in single-molecule experiments. PMID:27028638

  17. Impact of Hydrogel Structure and Composition on Autonomic Chemo-Mechanical Behavior

    NASA Astrophysics Data System (ADS)

    Kramb, Ryan; Buskohl, Philip; Vaia, Richard

    2014-03-01

    Autonomic materials harvest energy to change size, shape, or color in response to a set of environmental conditions. At the core of this biomimetic behavior is a material that transduces energy between forms (e.g. chemical to mechanical). The most widely studied of these materials are self-oscillating, Ru-containing PNIPAAm hydrogels driven by the Belousov -Zhabotinsky (BZ) reaction; and if correctly designed, BZ gels mimic biological process such as a quorum sensing or beating like a heart. However, establishing relationships between chemo-mechanical response and gel characteristics, such as crosslinking density, monomer composition, catalyst content, and gel stiffness, has remained elusive due to the limited material set and challenges in determining the appropriate balance of reaction kinetics and mechanical response necessary to establish self-sustaining oscillations. To address this challenge, we have broadened the suite of available monomers through a modular synthesis of the Ru-containing constituent; and thereby demonstrating facile tuning of the aforementioned characteristics of the BZ gel. From the resulting correlations between gel properties and chemo-mechanical response, we discuss the material design of composite autonomic gels for maximum shape change, directionality of oscillations, and synchronization of oscillations analogous to a natural pacemaker cell cluster.

  18. A chemo-mechanical free-energy-based approach to model durotaxis and extracellular stiffness-dependent contraction and polarization of cells.

    PubMed

    Shenoy, Vivek B; Wang, Hailong; Wang, Xiao

    2016-02-01

    We propose a chemo-mechanical model based on stress-dependent recruitment of myosin motors to describe how the contractility, polarization and strain in cells vary with the stiffness of their surroundings and their shape. A contractility tensor, which depends on the distribution of myosin motors, is introduced to describe the chemical free energy of the cell due to myosin recruitment. We explicitly include the contributions to the free energy that arise from mechanosensitive signalling pathways (such as the SFX, Rho-Rock and MLCK pathways) through chemo-mechanical coupling parameters. Taking the variations of the total free energy, which consists of the chemical and mechanical components, in accordance with the second law of thermodynamics provides equations for the temporal evolution of the active stress and the contractility tensor. Following this approach, we are able to recover the well-known Hill relation for active stresses, based on the fundamental principles of irreversible thermodynamics rather than phenomenology. We have numerically implemented our free energy-based approach to model spatial distribution of strain and contractility in (i) cells supported by flexible microposts, (ii) cells on two-dimensional substrates, and (iii) cells in three-dimensional matrices. We demonstrate how the polarization of the cells and the orientation of stress fibres can be deduced from the eigenvalues and eigenvectors of the contractility tensor. Our calculations suggest that the chemical free energy of the cell decreases with the stiffness of the extracellular environment as the cytoskeleton polarizes in response to stress-dependent recruitment of molecular motors. The mechanical energy, which includes the strain energy and motor potential energy, however, increases with stiffness, but the overall energy is lower for cells in stiffer environments. This provides a thermodynamic basis for durotaxis, whereby cells preferentially migrate towards stiffer regions of the

  19. A chemo-mechanical free-energy-based approach to model durotaxis and extracellular stiffness-dependent contraction and polarization of cells.

    PubMed

    Shenoy, Vivek B; Wang, Hailong; Wang, Xiao

    2016-02-01

    We propose a chemo-mechanical model based on stress-dependent recruitment of myosin motors to describe how the contractility, polarization and strain in cells vary with the stiffness of their surroundings and their shape. A contractility tensor, which depends on the distribution of myosin motors, is introduced to describe the chemical free energy of the cell due to myosin recruitment. We explicitly include the contributions to the free energy that arise from mechanosensitive signalling pathways (such as the SFX, Rho-Rock and MLCK pathways) through chemo-mechanical coupling parameters. Taking the variations of the total free energy, which consists of the chemical and mechanical components, in accordance with the second law of thermodynamics provides equations for the temporal evolution of the active stress and the contractility tensor. Following this approach, we are able to recover the well-known Hill relation for active stresses, based on the fundamental principles of irreversible thermodynamics rather than phenomenology. We have numerically implemented our free energy-based approach to model spatial distribution of strain and contractility in (i) cells supported by flexible microposts, (ii) cells on two-dimensional substrates, and (iii) cells in three-dimensional matrices. We demonstrate how the polarization of the cells and the orientation of stress fibres can be deduced from the eigenvalues and eigenvectors of the contractility tensor. Our calculations suggest that the chemical free energy of the cell decreases with the stiffness of the extracellular environment as the cytoskeleton polarizes in response to stress-dependent recruitment of molecular motors. The mechanical energy, which includes the strain energy and motor potential energy, however, increases with stiffness, but the overall energy is lower for cells in stiffer environments. This provides a thermodynamic basis for durotaxis, whereby cells preferentially migrate towards stiffer regions of the

  20. Chemo-Mechanical Characteristics of Mud Formed from Environmental Dust Particles in Humid Ambient Air.

    PubMed

    Hassan, Ghassan; Yilbas, B S; Said, Syed A M; Al-Aqeeli, N; Matin, Asif

    2016-01-01

    Mud formed from environmental dust particles in humid ambient air significantly influences the performance of solar harvesting devices. This study examines the characterization of environmental dust particles and the chemo-mechanics of dry mud formed from dust particles. Analytical tools, including scanning electron microscopy, atomic force microscopy, energy dispersive spectroscopy, particle sizing, and X-ray diffraction, are used to characterize dry mud and dust particles. A micro/nano tribometer is used to measure the tangential force and friction coefficient while tensile tests are carried out to assess the binding forces of dry mud pellets. After dry mud is removed, mud residuals on the glass surface are examined and the optical transmittance of the glass is measured. Dust particles include alkaline compounds, which dissolve in water condensate and form a mud solution with high pH (pH = 7.5). The mud solution forms a thin liquid film at the interface of dust particles and surface. Crystals form as the mud solution dries, thus, increasing the adhesion work required to remove dry mud from the surface. Optical transmittance of the glass is reduced after dry mud is removed due to the dry mud residue on the surface. PMID:27445272

  1. Chemo-Mechanical Characteristics of Mud Formed from Environmental Dust Particles in Humid Ambient Air.

    PubMed

    Hassan, Ghassan; Yilbas, B S; Said, Syed A M; Al-Aqeeli, N; Matin, Asif

    2016-01-01

    Mud formed from environmental dust particles in humid ambient air significantly influences the performance of solar harvesting devices. This study examines the characterization of environmental dust particles and the chemo-mechanics of dry mud formed from dust particles. Analytical tools, including scanning electron microscopy, atomic force microscopy, energy dispersive spectroscopy, particle sizing, and X-ray diffraction, are used to characterize dry mud and dust particles. A micro/nano tribometer is used to measure the tangential force and friction coefficient while tensile tests are carried out to assess the binding forces of dry mud pellets. After dry mud is removed, mud residuals on the glass surface are examined and the optical transmittance of the glass is measured. Dust particles include alkaline compounds, which dissolve in water condensate and form a mud solution with high pH (pH = 7.5). The mud solution forms a thin liquid film at the interface of dust particles and surface. Crystals form as the mud solution dries, thus, increasing the adhesion work required to remove dry mud from the surface. Optical transmittance of the glass is reduced after dry mud is removed due to the dry mud residue on the surface.

  2. Chemo-Mechanical Characteristics of Mud Formed from Environmental Dust Particles in Humid Ambient Air

    PubMed Central

    Hassan, Ghassan; Yilbas, B. S.; Said, Syed A. M.; Al-Aqeeli, N.; Matin, Asif

    2016-01-01

    Mud formed from environmental dust particles in humid ambient air significantly influences the performance of solar harvesting devices. This study examines the characterization of environmental dust particles and the chemo-mechanics of dry mud formed from dust particles. Analytical tools, including scanning electron microscopy, atomic force microscopy, energy dispersive spectroscopy, particle sizing, and X-ray diffraction, are used to characterize dry mud and dust particles. A micro/nano tribometer is used to measure the tangential force and friction coefficient while tensile tests are carried out to assess the binding forces of dry mud pellets. After dry mud is removed, mud residuals on the glass surface are examined and the optical transmittance of the glass is measured. Dust particles include alkaline compounds, which dissolve in water condensate and form a mud solution with high pH (pH = 7.5). The mud solution forms a thin liquid film at the interface of dust particles and surface. Crystals form as the mud solution dries, thus, increasing the adhesion work required to remove dry mud from the surface. Optical transmittance of the glass is reduced after dry mud is removed due to the dry mud residue on the surface. PMID:27445272

  3. Chemo-Mechanical Characteristics of Mud Formed from Environmental Dust Particles in Humid Ambient Air

    NASA Astrophysics Data System (ADS)

    Hassan, Ghassan; Yilbas, B. S.; Said, Syed A. M.; Al-Aqeeli, N.; Matin, Asif

    2016-07-01

    Mud formed from environmental dust particles in humid ambient air significantly influences the performance of solar harvesting devices. This study examines the characterization of environmental dust particles and the chemo-mechanics of dry mud formed from dust particles. Analytical tools, including scanning electron microscopy, atomic force microscopy, energy dispersive spectroscopy, particle sizing, and X-ray diffraction, are used to characterize dry mud and dust particles. A micro/nano tribometer is used to measure the tangential force and friction coefficient while tensile tests are carried out to assess the binding forces of dry mud pellets. After dry mud is removed, mud residuals on the glass surface are examined and the optical transmittance of the glass is measured. Dust particles include alkaline compounds, which dissolve in water condensate and form a mud solution with high pH (pH = 7.5). The mud solution forms a thin liquid film at the interface of dust particles and surface. Crystals form as the mud solution dries, thus, increasing the adhesion work required to remove dry mud from the surface. Optical transmittance of the glass is reduced after dry mud is removed due to the dry mud residue on the surface.

  4. Application of Silicon Selective Epitaxial Growth and Chemo-Mechanical Polishing to Bipolar and Soi Mosfet Devices.

    NASA Astrophysics Data System (ADS)

    Nguyen, Cuong Tan

    1994-01-01

    Polished Epitaxy, or the combination of silicon Selective Epitaxial Growth and Chemo-Mechanical Polishing, provides new flexibility in process and device design, including optimized isolation, planar active-area definition, low-capacitance contacts, and SOI thin films. In this work, Polished Epitaxy has been developed with particular effort on overcoming junction leakage problems widely reported in devices fabricated in similar processes. It was found that in addition to careful surface preparation and defect control in the selective epitaxy process, issues such as sidewall orientation, junction passivation, crystal annealing, and surface damage removal were equally important and needed to be addressed. Coupled with the proper processing steps, Polished Epitaxy was able to deliver material of comparable quality to bulk silicon, suitable for device applications. By growing epitaxy laterally over an oxide step followed by polishing, a pedestal structure was created in which a thin film of single-crystal silicon was formed over oxide. Serving as the extrinsic base contact to a T-Pedestal bipolar transistor device, this pedestal helped minimize the parasitic extrinsic-base-collector overlap capacitance. The cut-off frequency (f_ {T}) in a device with a 1.0-mu m wide emitter stripe was found to improve from 17GHz to 22GHz when the contact overlap was reduced from a more conventional, larger size of 1.0 mu m to 0.2 mum. It is expected that the high-frequency performance of this structure can still be improved further in an optimized process with reduced emitter and collector resistances. The same pedestal structure was applied to a Pedestal -SOI (Silicon-On-Insulator) MOSFET device concept. At one extreme, a conventional bulk MOSFET structure is obtained when the pedestal is not utilized; quasi-SOI occurs when the drain and part of the channel overlap with the pedestal over buried oxide; at the other extreme, complete-SOI behavior results when source, channel, and drain

  5. Interstitial fluid flow within bone canaliculi and electro-chemo-mechanical features of the canalicular milieu: a multi-parametric sensitivity analysis.

    PubMed

    Sansalone, Vittorio; Kaiser, Joanna; Naili, Salah; Lemaire, Thibault

    2013-06-01

    Canalicular fluid flow is acknowledged to play a major role in bone functioning, allowing bone cells' metabolism and activity and providing an efficient way for cell-to-cell communication. Bone canaliculi are small canals running through the bone solid matrix, hosting osteocyte's dendrites, and saturated by an interstitial fluid rich in ions. Because of the small size of these canals (few hundred nanometers in diameter), fluid flow is coupled with electrochemical phenomena. In our previous works, we developed a multi-scale model accounting for coupled hydraulic and chemical transport in the canalicular network. Unfortunately, most of the physical and geometrical information required by the model is hardly accessible by nowadays experimental techniques. The goal of this study was to numerically assess the influence of the physical and material parameters involved in the canalicular fluid flow. The focus was set on the electro-chemo-mechanical features of the canalicular milieu, hopefully covering any in vivo scenario. Two main results were obtained. First, the most relevant parameters affecting the canalicular fluid flow were identified and their effects quantified. Second, these findings were given a larger scope to cover also scenarios not considered in this study. Therefore, this study gives insight into the potential interactions between electrochemistry and mechanics in bone and provides the rational for further theoretical and experimental investigations.

  6. Randomized controlled clinical trial of long-term chemo-mechanical caries removal using PapacarieTM gel

    PubMed Central

    MOTTA, Lara Jansiski; BUSSADORI, Sandra Kalil; CAMPANELLI, Ana Paula; da SILVA, André Luis; ALFAYA, Thays Almeida; de GODOY, Camila Haddad Leal; NAVARRO, Maria Fidela de Lima

    2014-01-01

    Objectives Compare the effectiveness of PapacarieTM gel for the chemo-mechanical removal of carious lesions on primary teeth to conventional caries removal with a low-speed bur with regard to execution time, clinical aspects and radiographic findings. Material and Methods A randomized controlled clinical trial with a split-mouth design was carried out. The sample was composed of 20 children aged four to seven years, in whom 40 deciduous teeth were randomly divided into two groups: chemo-mechanical caries removal with PapacarieTM and removal of carious dentin with a low-speed bur. Each child underwent both procedures and served as his/her own control. Restorations were performed with glass ionomer cement. The time required to perform the procedure was also analyzed. The patients underwent longitudinal clinical and radiographic follow-up of the restorations. Results No statistically significant difference between groups was found regarding the time required to perform the procedures and the radiographic follow up. Statistically significant differences between groups were found in the clinical evaluation at 6 and 18 months after treatment. Conclusion PapacarieTM is as effective as the traditional method for the removal of carious dentin on deciduous teeth, but offers the advantages of the preservation of sound dental tissue as well as the avoidance of sharp rotary instruments and local anesthesia. PMID:25141203

  7. Efficacy of lasers as an adjunct to chemo-mechanical disinfection of infected root canals: a systematic review.

    PubMed

    Fransson, H; Larsson, K M; Wolf, E

    2013-04-01

    The aim was to evaluate the efficacy of various types of lasers used as an adjunct to chemo-mechanical disinfection of infected root canals with the outcome measures 'normal periapical condition' or 'reduction of microbial load'. PubMed, CENTRAL and ISI Web of Knowledge literature searches with specific indexing terms and a subsequent hand search were made with stated limits and criteria. Relevant publications were retrieved, followed by interpretation. The quality of each included publication was assessed as high, moderate or low. The initial search process yielded 234 publications. All abstracts of these publications were read, and the reference lists of relevant publications were hand-searched. Ten articles were read in full text and interpreted according to a data extraction form. Five were included in the systematic review and were assessed. A meta-analysis was impossible to perform because the included studies were heterogeneous with regard to study design, treatment and outcome measures. Positive effects were reported; however, no concluding evidence grade could be made because each included study was judged to have low quality, primarily due to lack of a power analysis, blinding and reproducibility. The evidence grade for whether lasers can be recommended as an adjunct to chemo-mechanical disinfection of infected root canals was insufficient. This does not necessarily imply that laser should not be used as an adjunct to root canal treatment but instead underscores the need for future high-quality studies.

  8. Slime mould foraging behaviour as optically coupled logical operations

    NASA Astrophysics Data System (ADS)

    Mayne, R.; Adamatzky, A.

    2015-04-01

    Physarum polycephalum is a macroscopic plasmodial slime mould whose apparently 'intelligent' behaviour patterns may be interpreted as computation. We employ plasmodial phototactic responses to construct laboratory prototypes of NOT and NAND logical gates with electrical inputs/outputs and optical coupling in which the slime mould plays dual roles of computing device and electrical conductor. Slime mould logical gates are fault tolerant and resettable. The results presented here demonstrate the malleability and resilience of biological systems and highlight how the innate behaviour patterns of living substrates may be used to implement useful computation.

  9. Chemo-mechanical microscale characterization of materials heterogeneity in oil/gas shales: linking organics and inorganics

    NASA Astrophysics Data System (ADS)

    Ferralis, N.; Abedi, S.; Grossman, J. C.; Ulm, F.

    2013-12-01

    From a materials perspective, the unconventional peculiarity of oil/gas shales resides in the intrinsic multi-scale heterogeneity in their chemical composition, organic maturity, mineralogy and microtexture. In contrast to common assumptions of maturity being driven only by the reservoir conditions (temperature and pressure), the presence of organic matter with different maturity within a few microns apart calls into question the role played by the organic and mineral heterogeneity into the chemo-mechanical properties of the material. Understanding how the upscaling of chemical diversity affects the fracturability and in general the mechanical strength of oil/gas shales is crucial. Compared to conventional oil and gas reservoirs, as well as coal, such heterogeneity requires novel and additional characterization tools from nano- to macro-scales to allow for a complete understanding of the role played by such heterogeneity in the chemo- mechanical properties of gas shales. Here we present a novel suite of chemical and mineralogical characterization tools that allow the in situ, non-destructive imaging of organic maturity and mineralogy from the microscale to the millimeter scale. This method is based on a combination of Raman, fluorescence and UV-Visible absorption spectroscopy. The upscaling is designed to provide a maturity population distribution from the nanoscale to the conventionally used macro-scale averaged parameters (such as vitrinite reflectance). Furthermore, in combination with registered micro/nano-mechanical indentation data a direct correlation of fracture mechanics and chemistry is made, allowing for the determination of high yield strain regions, relations between organic and inorganic anisotropy and interface mechanics. The underlying scientific insight at the nano and micro-scale of the potential origin of fractures in oil/gas shales, will potentially provide a connection bottom-up link to continuum fracture mechanics.

  10. A comparative microbiological study to assess caries excavation by conventional rotary method and a chemo-mechanical method

    PubMed Central

    Anegundi, Rajesh T.; Patil, Shruthi B.; Tegginmani, Viresh; Shetty, Sheetal D.

    2012-01-01

    Aims: This study was aimed to determine the effectiveness of Papacárie® for caries removal as compared to the conventional method with respect to microbial flora, time, the amount of tissue removal, child's behavior, pain perception, and preference of treatment. Materials and Methods: Sixty primary molars of 30 children of age 4-9 years were selected randomly and divided into two groups of 30 teeth each: Group A treated by conventional method and group B with Papacárie® method. Results: Comparatively, no statistical difference was seen in microbial growth, total bacterial count, and lactobacilli count in both the groups (P = 0.36). The mean cavity entrance size with group A was 0.98133 mm and group B was 0.26083 mm (P < 0.001). The mean preparation time for group A was 4.7 Mins (minutes) and group B was 17.96 min s (P < 0.001). Majority of kids of both group A and B scored 3 (Frankl Behavior Rating Scale) before and after the treatment showing no statistical difference in their behavioral score (P = 1). In group A 50% of children experienced no pain as compared to 86.7% in group B (P = 0.01). There was no statistical difference in the preference of treatment (P = 0.12). Conclusion: Thus, the Chemo mechanical caries removal method can be considered as an effective method to control pain and preserve sound tooth structure during caries excavation. PMID:23633794

  11. Molecular control of myocardial mechanics and energetics: the chemo-mechanical conversion.

    PubMed

    Landesberg, A

    1997-01-01

    Energy consumption in the cardiac muscle is characterized by two basic phenomena: 1) The well known linear relationship between energy consumption by the sarcomere and the mechanical energy it generates, and 2) the ability to modulate the generated mechanical energy and energy consumption to the various loading conditions, as is manifested by the Frank-Starling Law and the Fenn effect. These basic phenomena are analyzed here based on coupling calcium kinetics with crossbridge (Xb) cycling. Our previous studies established the existence of two feedback mechanism: 1) a positive feedback mechanism, the cooperativity, whereby the affinity of the troponin for calcium, and hence Xb and actomyosin-ATPase recruitment, depends on the number of force generating Xbs, and 2) a mechanical feedback, whereby the filaments shortening velocity, or the Xb strain rate, determines the rate of Xb turnover from the strong to the weak conformation. The cooperativity mechanism determines the force-length relationship (FLR) and the related Frank-Starling Law. It also provides the basis for the regulation of energy consumption and the ability of the muscle to adapt its energy consumption to the loading conditions. The mechanical feedback regulates the shortening velocity and provides the analytical solution for the experimentally derived Hill's equation for the force-velocity relationship (FVR). The mechanical feedback regulates the generated power and provides the linear relationship between energy consumption and the generated mechanical energy, i.e., the external work done and the liberated heat. Thus, the two feedback mechanisms that regulate sarcomere dynamics, and determine the FLR and FVR, also regulate the energy consumption and the mechanical energy generated by the muscle.

  12. Insights into collective cell behaviour from populations of coupled chemical oscillators.

    PubMed

    Taylor, Annette F; Tinsley, Mark R; Showalter, Kenneth

    2015-08-21

    Biological systems such as yeast show coordinated activity driven by chemical communication between cells. Here, we show how experiments with coupled chemical oscillators can provide insights into collective behaviour in cellular systems. Two methods of coupling the oscillators are described: exchange of chemical species with the surrounding solution and computer-controlled illumination of a light-sensitive catalyst. The collective behaviour observed includes synchronisation, dynamical quorum sensing (a density dependent transition to population-wide oscillations), and chimera states, where oscillators spontaneously split into coherent and incoherent groups. At the core of the different types of behaviour lies an intracellular autocatalytic signal and an intercellular communication mechanism that influences the autocatalytic growth.

  13. True-slime-mould-inspired hydrostatically coupled oscillator system exhibiting versatile behaviours.

    PubMed

    Umedachi, Takuya; Idei, Ryo; Ito, Kentaro; Ishiguro, Akio

    2013-09-01

    Behavioural diversity is an indispensable attribute of living systems, which makes them intrinsically adaptive and responsive to the demands of a dynamically changing environment. In contrast, conventional engineering approaches struggle to suppress behavioural diversity in artificial systems to reach optimal performance in given environments for desired tasks. The goals of this research include understanding the essential mechanism that endows living systems with behavioural diversity and implementing the mechanism in robots to exhibit adaptive behaviours. For this purpose, we have focused on an amoeba-like unicellular organism: the plasmodium of true slime mould. Despite the absence of a central nervous system, the plasmodium exhibits versatile spatiotemporal oscillatory patterns and switches spontaneously among these patterns. By exploiting this behavioural diversity, it is able to exhibit adaptive behaviour according to the situation encountered. Inspired by this organism, we built a real physical robot using hydrostatically coupled oscillators that produce versatile oscillatory patterns and spontaneous transitions among the patterns. The experimental results show that exploiting physical hydrostatic interplay—the physical dynamics of the robot—allows simple phase oscillators to promote versatile behaviours. The results can contribute to an understanding of how a living system generates versatile and adaptive behaviours with physical interplays among body parts.

  14. Glucose-driven chemo-mechanical autonomous drug-release system with multi-enzymatic amplification toward feedback control of blood glucose in diabetes.

    PubMed

    Munkhjargal, Munkhbayar; Hatayama, Kohdai; Matsuura, Yuki; Toma, Koji; Arakawa, Takahiro; Mitsubayashi, Kohji

    2015-05-15

    A second-generation novel chemo-mechanical autonomous drug release system, incorporating various improvements over our first-generation system, was fabricated and evaluated. Enhanced oxygen uptake by the enzyme membrane of the organic engine was facilitated by optimizing the quantity of enzyme immobilizer, PVA-SbQ, and by hydrophobizing the membrane surface. Various quantities of PVA-SbQ were evaluated in the organic engine by measuring the decompression rate, with 1.5 mg/cm(2) yielding optimum results. When fluororesin was used as a hydrophobizing coating, the time to reach the peak decompression rate was shortened 2.3-fold. The optimized elements of the system were evaluated as a unit, first in an open loop and then in a closed loop setting, using a mixture of glucose solution (25 mmol/L), ATP and MgCI2 with glucose hexokinase enzyme (HK) as a glucose reducer. In conclusion, feedback-control of physiologically relevant glucose concentration was demonstrated by the second-generation drug release system without any requirement for external energy. PMID:25223550

  15. Micro-structural analysis of local damage introduced in subsurface regions of 4H-SiC wafers during chemo-mechanical polishing

    NASA Astrophysics Data System (ADS)

    Sako, Hideki; Matsuhata, Hirofumi; Sasaki, Masayuki; Nagaya, Masatake; Kido, Takanori; Kawata, Kenji; Kato, Tomohisa; Senzaki, Junji; Kitabatake, Makoto; Okumura, Hajime

    2016-04-01

    The surface morphology and lattice defect structures in the subsurface regions of 4H-SiC wafers introduced during chemo-mechanical polishing (CMP) were studied by scanning electron microscopy and transmission electron microscopy. It is known that local damage consisting of high-density lattice defects is introduced in the wafers during the current CMP, however, optical microscopy showed that the surface was very flat and clean without any presence of surface defects. Specifically, this study focused on the detailed analysis of such lattice defect structures. The high-density lattice defects locally introduced in the subsurface regions consisted of nano-scale surface scratches, high-density basal-plane dislocation loops, Shockley-type stacking faults, and Y-shaped defects. Two types of dislocation loops were introduced near the scratches that were selected for further study: nearly perfect basal-plane dislocations, which were accompanied by narrow stacking faults, and apparent partial basal-plane dislocations, which were accompanied by wide stacking faults. A Y-shaped defect was observed in the local damage along the [ 11 2 ¯ 0 ] direction, but not in the local damage along the [ 1 ¯100 ] direction. It was also found that the directions of the Burgers vectors for the basal-plane dislocations clearly depended on the directions of the introduced scratch-like defects.

  16. Characterization of time-varying macroscopic electro-chemo-mechanical behavior of SOFC subjected to Ni-sintering in cermet microstructures

    NASA Astrophysics Data System (ADS)

    Muramatsu, M.; Terada, K.; Kawada, T.; Yashiro, K.; Takahashi, K.; Takase, S.

    2015-10-01

    In order to perform stress analyses of a solid oxide fuel cell (SOFC) under operation, we propose a characterization method of its time-varying macroscopic electro-chemo-mechanical behavior of electrodes by considering the time-varying geometries of anode microstructures due to Ni-sintering. The phase-field method is employed to simulate the micro-scale morphology change with time, from which the time-variation of the amount of triple-phase boundaries is directly predicted. Then, to evaluate the time-variation of the macroscopic oxygen ionic and electronic conductivities and the inelastic properties of the anode electrode, numerical material tests based on the homogenization method are conducted for each state of sintered microstructures. In these homogenization analyses, we also have to consider the dependencies of the properties of constituent materials on the temperature and/or the oxygen potential that is supposed to change within an operation period. To predict the oxygen potential distribution in an overall SOFC structure under long-period operation, which determines reduction-induced expansive/contractive deformation of oxide materials, an unsteady problem of macroscopic oxygen ionic and electronic conductions is solved. Using the calculated stress-free strains and the homogenized mechanical properties, both of which depend on the operational environment, we carry out the macroscopic stress analysis of the SOFC.

  17. Chemo-mechanical modification of cottonwood for Pb(2+) removal from aqueous solutions: Sorption mechanisms and potential application as biofilter in drip-irrigation.

    PubMed

    Mosa, Ahmed; El-Ghamry, Ayman; Trüby, Peter; Omar, Mahmoud; Gao, Bin; Elnaggar, Abdelhamid; Li, Yuncong

    2016-10-01

    Using biomass (e.g. crop residues) and its derivatives as biosorbents have been recognized as an eco-friendly technique for wastewater decontamination. In this study, mechanically modified cottonwood was further activated with KOH to improve its sorption of Pb(2+). In addition, its potential as a biofilter to safeguard radish (Raphanus sativus, L.) against Pb-stress was evaluated in a gravity-fed drip irrigation system. Physiochemical properties of the chemo-mechanically activated cottonwood (CMACW) and the mechanically activated cottonwood (MACW) before and after sorption process were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), digital selected-area electron diffraction (SAED) and Fourier transform infrared spectroscopy (FTIR). After activation, several sorption mechanisms (i.e. precipitation, electrostatic outer- and inner-sphere complexation) were responsible for the higher sorption capacity of CMACW as compared with MACW (8.55 vs. 7.28 mg g(-1)). Sorption kinetics and isotherms fitted better with the pseudo-second-order and Langmuir models as compared with the pseudo-first-order and Freundlich models, respectively. In the gravity-fed drip irrigation system, the CMACW biofilter reduced the accumulation of Pb in radish roots and shoots and avoided reaching the toxic limits in some cases. Soil types had a significant effect on Pb(2+) bioavailability because of the difference in sorption ability. Findings from this study showed that CMACW biofilter can be used as a safeguard for wastewater irrigation. PMID:27393935

  18. Glucose-driven chemo-mechanical autonomous drug-release system with multi-enzymatic amplification toward feedback control of blood glucose in diabetes.

    PubMed

    Munkhjargal, Munkhbayar; Hatayama, Kohdai; Matsuura, Yuki; Toma, Koji; Arakawa, Takahiro; Mitsubayashi, Kohji

    2015-05-15

    A second-generation novel chemo-mechanical autonomous drug release system, incorporating various improvements over our first-generation system, was fabricated and evaluated. Enhanced oxygen uptake by the enzyme membrane of the organic engine was facilitated by optimizing the quantity of enzyme immobilizer, PVA-SbQ, and by hydrophobizing the membrane surface. Various quantities of PVA-SbQ were evaluated in the organic engine by measuring the decompression rate, with 1.5 mg/cm(2) yielding optimum results. When fluororesin was used as a hydrophobizing coating, the time to reach the peak decompression rate was shortened 2.3-fold. The optimized elements of the system were evaluated as a unit, first in an open loop and then in a closed loop setting, using a mixture of glucose solution (25 mmol/L), ATP and MgCI2 with glucose hexokinase enzyme (HK) as a glucose reducer. In conclusion, feedback-control of physiologically relevant glucose concentration was demonstrated by the second-generation drug release system without any requirement for external energy.

  19. Sensitivity Comparison of Vapor Trace Detection of Explosives Based on Chemo-Mechanical Sensing with Optical Detection and Capacitive Sensing with Electronic Detection

    PubMed Central

    Strle, Drago; Štefane, Bogdan; Zupanič, Erik; Trifkovič, Mario; Maček, Marijan; Jakša, Gregor; Kvasič, Ivan; Muševič, Igor

    2014-01-01

    The article offers a comparison of the sensitivities for vapour trace detection of Trinitrotoluene (TNT) explosives of two different sensor systems: a chemo-mechanical sensor based on chemically modified Atomic Force Microscope (AFM) cantilevers based on Micro Electro Mechanical System (MEMS) technology with optical detection (CMO), and a miniature system based on capacitive detection of chemically functionalized planar capacitors with interdigitated electrodes with a comb-like structure with electronic detection (CE). In both cases (either CMO or CE), the sensor surfaces are chemically functionalized with a layer of APhS (trimethoxyphenylsilane) molecules, which give the strongest sensor response for TNT. The construction and calibration of a vapour generator is also presented. The measurements of the sensor response to TNT are performed under equal conditions for both systems, and the results show that CE system with ultrasensitive electronics is far superior to optical detection using MEMS. Using CMO system, we can detect 300 molecules of TNT in 10+12 molecules of N2 carrier gas, whereas the CE system can detect three molecules of TNT in 10+12 molecules of carrier N2. PMID:24977388

  20. Coupling tendencies during exploratory behaviours of competing players in rugby union dyads.

    PubMed

    Correia, Vanda; Passos, Pedro; Araújo, Duarte; Davids, Keith; Diniz, Ana; Kelso, J A Scott

    2016-01-01

    This study investigated interpersonal coordination tendencies in 1vs.1 dyads in rugby union, here expressed by participants' movement velocity towards or away from the sideline as they competed to score or prevent a try. We examined whether coupling tendencies of members of each dyad shaped key performance outcomes (try or successful tackle). Data on movement displacement trajectories of eight male rugby union players (aged 11-12 years) were analysed during performance in 47 trials. To assess coordination tendencies during exploratory behaviours in the dyads, analyses of performance time series data were undertaken using variable time graphs, running correlations and cross-correlations. Results revealed distinct coupling patterns characterised by shifts between synchronous coordination and asynchronous coordination tendencies and uncoordinated actions. Observed behaviours were interpreted as attempts of competing participants to create and perceive possibilities for action while seeking to achieve specific performance goals. Findings also revealed that a variety of patterned relations between participants resulted in different performance outcomes.

  1. Emergence of global scaling behaviour in the coupled Earth-atmosphere interaction

    PubMed Central

    Fallah, Bijan; Saberi, Abbas Ali; Sodoudi, Sahar

    2016-01-01

    Scale invariance property in the global geometry of Earth may lead to a coupled interactive behaviour between various components of the climate system. One of the most interesting correlations exists between spatial statistics of the global topography and the temperature on Earth. Here we show that the power-law behaviour observed in the Earth topography via different approaches, resembles a scaling law in the global spatial distribution of independent atmospheric parameters. We report on observation of scaling behaviour of such variables characterized by distinct universal exponents. More specifically, we find that the spatial power-law behaviour in the fluctuations of the near surface temperature over the lands on Earth, shares the same universal exponent as of the global Earth topography, indicative of the global persistent role of the static geometry of Earth to control the steady state of a dynamical atmospheric field. Such a universal feature can pave the way to the theoretical understanding of the chaotic nature of the atmosphere coupled to the Earth’s global topography. PMID:27666675

  2. Emergence of global scaling behaviour in the coupled Earth-atmosphere interaction

    NASA Astrophysics Data System (ADS)

    Fallah, Bijan; Saberi, Abbas Ali; Sodoudi, Sahar

    2016-09-01

    Scale invariance property in the global geometry of Earth may lead to a coupled interactive behaviour between various components of the climate system. One of the most interesting correlations exists between spatial statistics of the global topography and the temperature on Earth. Here we show that the power-law behaviour observed in the Earth topography via different approaches, resembles a scaling law in the global spatial distribution of independent atmospheric parameters. We report on observation of scaling behaviour of such variables characterized by distinct universal exponents. More specifically, we find that the spatial power-law behaviour in the fluctuations of the near surface temperature over the lands on Earth, shares the same universal exponent as of the global Earth topography, indicative of the global persistent role of the static geometry of Earth to control the steady state of a dynamical atmospheric field. Such a universal feature can pave the way to the theoretical understanding of the chaotic nature of the atmosphere coupled to the Earth’s global topography.

  3. [Children's Aggressive Behaviour and Therapeutic Interventions on the Parental Couple Level].

    PubMed

    Lux, Ulrike; Hudecek, Matthias

    2015-01-01

    Parents go to see child guidance counselling services for many different reasons. Behavioural problems or rather enraged or aggressive behaviour of children and adolescents towards their siblings or parents is a frequent issue in counselling practice. The current article takes a closer look at the range of problems around defiance, anger and aggression from a developmental and systemic point of view. The meaning of these negative affects within the family system is elaborated. Empirical studies show a clear connection between children's problem behaviour and frequent and destructive interparental conflict. So called spill-over-effects play a crucial role in explaining this connection. From a systemic perspective thus the child is seen as a symptom carrier, which shifts the focus of counselling on the interaction between parents as well. Consequently, family therapeutic sessions on the couple level are often indicated. Do parents succeed in constructively solving their conflicts, typically the aggressive behaviour of the children is reduced, too. On the basis of a compound single case such a process is illustrated.

  4. Exploring Early Angiosperm Fire Feedbacks using Coupled Experiments and Modelling Approaches to Estimate Cretaceous Palaeofire Behaviour

    NASA Astrophysics Data System (ADS)

    Belcher, Claire; Hudpsith, Victoria

    2016-04-01

    Using the fossil record we are typically limited to exploring linkages between palaeoecological changes and palaeofire activity by assessing the abundance of charcoals preserved in sediments. However, it is the behaviour of fires that primarily governs their ecological effects. Therefore, the ability to estimate variations in aspects of palaeofire behaviour such as palaeofire intensity and rate of spread would be of key benefit toward understanding the coupled evolutionary history of ecosystems and fire. The Cretaceous Period saw major diversification in land plants. Previously, conifers (gymnosperms) and ferns (pteridophytes) dominated Earth's ecosystems until flowering plants (angiosperms) appear in the fossil record of the Early Cretaceous (~135Ma). We have created surface fire behaviour estimates for a variety of angiosperm invasion scenarios and explored the influence of Cretaceous superambient atmospheric oxygen levels on the fire behaviour occurring in these new Cretaceous ecosystems. These estimates are then used to explore the hypothesis that the early spread of the angiosperms was promoted by the novel fire regimes that they created. In order to achieve this we tested the flammability of Mesozoic analogue fuel types in controlled laboratory experiments using an iCone calorimeter, which measured the ignitability as well as the effective heat of combustion of the fuels. We then used the BehavePlus fire behaviour modelling system to scale up our laboratory results to the ecosystem scale. Our results suggest that fire-angiosperm feedbacks may have occurred in two phases: The first phase being a result of weedy angiosperms providing an additional easily ignitable fuel that enhanced both the seasonality and frequency of surface fires. In the second phase, the addition of shrubby understory fuels likely expanded the number of ecosystems experiencing more intense surface fires, resulting in enhanced mortality and suppressed post-fire recruitment of gymnosperms

  5. Numerical calculation of the transient behaviour of two pure cross-flow heat exchangers coupled by a circulating flow stream

    NASA Astrophysics Data System (ADS)

    Na Ranong, Chakkrit; Hapke, Jobst; Roetzel, Wilfried

    2010-11-01

    The transient thermal behaviour of a heat shifting system consisting of two pure cross-flow heat exchangers coupled by a circulating flow stream is studied theoretically. A suitable mathematical description of the system is based on the energy balance equation for general flow processes yielding a system of coupled hyperbolic partial differential equations in two dimensions. System responses to perturbations of inlet temperatures and mass flow rates are numerically calculated with an explicit finite difference method. A criterion for the generation of computational grids minimising effects of numerical dispersion and dissipation is applied to the system of coupled pure cross-flow heat exchangers which has not been considered up to now. Due to its internal circulation the coupled system shows a different behaviour compared to single cross-flow heat exchangers like inverse response and oscillatory behaviour to non-oscillating input signals.

  6. Saturation behaviour of colloidal PbSe quantum dot exciton emission coupled into silicon photonic circuits.

    PubMed

    Foell, Charles A; Schelew, Ellen; Qiao, Haijun; Abel, Keith A; Hughes, Stephen; van Veggel, Frank C J M; Young, Jeff F

    2012-05-01

    We report coupling of the excitonic photon emission from photoexcited PbSe colloidal quantum dots (QDs) into an optical circuit that was fabricated in a silicon-on-insulator wafer using a CMOS-compatible process. The coupling between excitons and sub-μm sized silicon channel waveguides was mediated by a photonic crystal microcavity. The intensity of the coupled light saturates rapidly with the optical excitation power. The saturation behaviour was quantitatively studied using an isolated photonic crystal cavity with PbSe QDs site-selectively located at the cavity mode antinode position. Saturation occurs when a few μW of continuous wave HeNe pump power excites the QDs with a Gaussian spot size of 2 μm. By comparing the results with a master equation analysis that rigorously accounts for the complex dielectric environment of the QD excitons, the saturation is attributed to ground state depletion due to a non-radiative exciton decay channel with a trap state lifetime ~ 3 μs.

  7. Saturation behaviour of colloidal PbSe quantum dot exciton emission coupled into silicon photonic circuits.

    PubMed

    Foell, Charles A; Schelew, Ellen; Qiao, Haijun; Abel, Keith A; Hughes, Stephen; van Veggel, Frank C J M; Young, Jeff F

    2012-05-01

    We report coupling of the excitonic photon emission from photoexcited PbSe colloidal quantum dots (QDs) into an optical circuit that was fabricated in a silicon-on-insulator wafer using a CMOS-compatible process. The coupling between excitons and sub-μm sized silicon channel waveguides was mediated by a photonic crystal microcavity. The intensity of the coupled light saturates rapidly with the optical excitation power. The saturation behaviour was quantitatively studied using an isolated photonic crystal cavity with PbSe QDs site-selectively located at the cavity mode antinode position. Saturation occurs when a few μW of continuous wave HeNe pump power excites the QDs with a Gaussian spot size of 2 μm. By comparing the results with a master equation analysis that rigorously accounts for the complex dielectric environment of the QD excitons, the saturation is attributed to ground state depletion due to a non-radiative exciton decay channel with a trap state lifetime ~ 3 μs. PMID:22565670

  8. Coupling submesoscale physics to seabirds behaviour at the ocean-atmosphere interface

    NASA Astrophysics Data System (ADS)

    De Monte, S.; Cotté, C.; d'Ovidio, F.; Lévy, M.; Le Corre, M.; Weimerskirch, H.

    2012-04-01

    During their journeys, seabirds are faced to environmental heterogeneity of the scale of tens of Kms in extension and of days in duration, that are induced in the open ocean by mesoscale and submesoscale turbulence. We combine tracking of frigatebirds in the Mozambique channel - available for the first time with 3-D resolution - and multisatellite-based nonlinear diagnostics to inquire how birds respond to the coupled ocean-atmosphere physics. Birds behaviour along their flight trajectory are categorized in 5 classes of vertical displacement, e.g. slow or fast descents, and are superimposed with the submesoscale structures obtained by a Lagrangian reanalysis or remote-sensing measures. We show that frigatebirds modify their behaviour at such scale over and outside transport and thermal fronts. We suggest that birds colocalization with structures generated by horizontal transport is a consequence of their quest for food (preferentially located on thermal fronts) but also for upward vertical wind. Our multidisciplinary method can be applied to forthcoming high-resolution animal tracking data and contribute to elucidate the response of marine ecosystems to environmental change.

  9. Diffraction aperture non-ideal behaviour of air coupled transducers array elements designed for NDT.

    PubMed

    Prego Borges, J L; Montero de Espinosa, F; Salazar, J; Garcia-Alvarez, J; Chávez, J A; Turó, A; Garcia-Hernandez, M J

    2006-12-22

    Air coupled piezoelectric ultrasonic array transducers are a novel tool that could lead to interesting advances in the area of non-contact laminar material testing using Lamb wave's propagation techniques. A key issue on the development of such transducers is their efficient coupling to air media (impedance mismatch between the piezoelectric material and air is 90 dB or more). Adaptation layers are used in order to attain good matching and avoid possible serious signal degradation. However, the introduction of these matching layers modify the transducer surface behaviour and, consequently, radiation characteristics are altered, making the usual idealization criteria (of uniform surface movement) adopted for field simulation purposes inaccurate. In our system, we have a concave linear-array transducer of 64 elements (electrically coupled by pairs) working at 0.8 MHz made of PZ27 rectangular piezoceramics (15 mm x 0.3 mm) with two matching layers made of polyurethane and porous cellulose bonded on them. Experimental measurements of the acoustic aperture of single excited array elements have shown an increment on the geometrical dimensions of its active surface. A sub-millimeter vibrometer laser scan has revealed an extension of the aperture beyond the supposed physical single array element dimensions. Non-uniform symmetric apodized velocity surface vibration amplitude profile with a concave delay contour indicates the presumed existence of travelling wave phenomena over the surface of the outer array matching layer. Also, asymptotic propagation velocities around 2500 m/s and attenuation coefficient between 15 and 20 dB/mm has been determined for the travelling waves showing clear tendencies. Further comparisons between the experimental measurements of single array element field radiation diagram and simulated equivalent aperture counterpart reveal good agreement versus the ideal (uniform displaced) rectangular aperture. For this purpose an Impulse Response Method

  10. Static and dynamic strain coupling behaviour of ferroic and multiferroic perovskites from resonant ultrasound spectroscopy.

    PubMed

    Carpenter, M A

    2015-07-01

    Resonant ultrasound spectroscopy (RUS) provides a window on the pervasive influence of strain coupling at phase transitions in perovskites through determination of elastic and anelastic relaxations across wide temperature intervals and with the application of external fields. In particular, large variations of elastic constants occur at structural, ferroelectric and electronic transitions and, because of the relatively long interaction length provided by strain fields in a crystal, Landau theory provides an effective formal framework for characterizing their form and magnitude. At the same time, the Debye equations provide a robust description of dynamic relaxational processes involving the mobility of defects which are coupled with strain. Improper ferroelastic transitions driven by octahedral tilting in KMnF3, LaAlO3, (Ca,Sr)TiO3, Sr(Ti,Zr)O3 and BaCeO3 are accompanied by elastic softening of tens of % and characteristic patterns of acoustic loss due to the mobility of twin walls. RUS data for ferroelectrics and ferroelectric relaxors, including BaTiO3, (K,Na)NbO3,Pb(Mg1/3Nb2/3)O3 (PMN), Pb(Sc1/2Ta1/2)O3 (PST), (Pb(Zn1/3Nb2/3)O3)0.955(PbTiO3)0.045 (PZN-PT) and (Pb(In1/2Nb1/2)O3)0.26(Pb(Mg1/3Nb2/3)O3)0.44(PbTiO3)0.30 (PIN-PMN-PT) show similar patterns of softening and attenuation but also have precursor softening associated with the development of polar nano regions. Defect-induced ferroelectricity occurs in KTaO3, without the development of long range ordering. By way of contrast, spin-lattice coupling is much more variable in strength, as reflected in a greater range of softening behaviour for Pr0.48Ca0.52MnO3 and Sm0.6Y0.4MnO3 as well as for the multiferroic perovskites EuTiO3,BiFeO3, Bi0.9Sm0.1FeO3, Bi0.9Nd0.1FeO3, (BiFeO3)0.64(CaFeO2.5)0.36, (Pb(Fe0.5Ti0.5)O3)0.4(Pb(Zr0.53Ti0.47)O3)0.6. A characteristic feature of transitions in which there is a significant Jahn-Teller component is softening as the transition point is approached from above, as illustrated by

  11. Effect of Couples Counselling on Reported HIV Risk Behaviour among HIV Serodiscordant Couples by ART Use, HIV Status and Gender in Rural Uganda

    PubMed Central

    King, Rachel; Min, Jeong; Birungi, Josephine; Nyonyintono, Maureen; Muldoon, Katherine A.; Khanakwa, Sarah; Kaleebu, Pontiano; Moore, David M.

    2015-01-01

    Background We examined several measures of self-reported HIV risk behaviour in mutually disclosed sero-discordant couples over time to see if a couples counselling intervention was associated with changes in these behaviors. Methods We analysed data from a prospective cohort study of HIV sero-discordant couples in Jinja, Uganda collected between June 2009 and December 2011. Participants received couples counselling, at 3-monthly intervals. We examined trends in reported condom-use, number of concurrent sexual partners, knowledge of HIV serostatus of concurrent partners and condom use of concurrent partners using Generalized Estimating Equation models, comparing responses at study enrollment with responses at six, 12 18 and 24 months of follow-up. Results A total of 586 couples were enrolled and the female member was HIV positive in 255 (44%) of them. The median age for female participants was 35 years and 42 years for men. Reported condom use at last sex with spouse increased over time (p<0.001) with the largest increases found among couples where the positive participant never received ART during the study(an increase from 68.8% at enrollment to 97.1% at 24 months). Male participants reported reductions in the number of concurrent sexual partners (p<0.001), increase in the knowledge of the HIV serostatus of these partners (p = 0.001) and a trend towards improved condom-use among non-primary partners (p = 0.070). Reported reduced risky behaviors did not wane over the study period. Conclusion Couples counselling resulted in increased condom use among all participants and among men the intervention resulted in reductions in risk behaviour with concurrent sexual partners. Routine counselling for serodiscordant couples should be integrated in routine ART care programs. PMID:26384103

  12. Self-Organized Criticality, Plasticity and Sensorimotor Coupling. Explorations with a Neurorobotic Model in a Behavioural Preference Task

    PubMed Central

    Aguilera, Miguel; Barandiaran, Xabier E.; Bedia, Manuel G.; Seron, Francisco

    2015-01-01

    During the last two decades, analysis of 1/ƒ noise in cognitive science has led to a considerable progress in the way we understand the organization of our mental life. However, there is still a lack of specific models providing explanations of how 1/ƒ noise is generated in coupled brain-body-environment systems, since existing models and experiments typically target either externally observable behaviour or isolated neuronal systems but do not address the interplay between neuronal mechanisms and sensorimotor dynamics. We present a conceptual model of a minimal neurorobotic agent solving a behavioural task that makes it possible to relate mechanistic (neurodynamic) and behavioural levels of description. The model consists of a simulated robot controlled by a network of Kuramoto oscillators with homeostatic plasticity and the ability to develop behavioural preferences mediated by sensorimotor patterns. With only three oscillators, this simple model displays self-organized criticality in the form of robust 1/ƒ noise and a wide multifractal spectrum. We show that the emergence of self-organized criticality and 1/ƒ noise in our model is the result of three simultaneous conditions: a) non-linear interaction dynamics capable of generating stable collective patterns, b) internal plastic mechanisms modulating the sensorimotor flows, and c) strong sensorimotor coupling with the environment that induces transient metastable neurodynamic regimes. We carry out a number of experiments to show that both synaptic plasticity and strong sensorimotor coupling play a necessary role, as constituents of self-organized criticality, in the generation of 1/ƒ noise. The experiments also shown to be useful to test the robustness of 1/ƒ scaling comparing the results of different techniques. We finally discuss the role of conceptual models as mediators between nomothetic and mechanistic models and how they can inform future experimental research where self-organized critically includes

  13. Gpr176 is a Gz-linked orphan G-protein-coupled receptor that sets the pace of circadian behaviour

    PubMed Central

    Doi, Masao; Murai, Iori; Kunisue, Sumihiro; Setsu, Genzui; Uchio, Naohiro; Tanaka, Rina; Kobayashi, Sakurako; Shimatani, Hiroyuki; Hayashi, Hida; Chao, Hsu-Wen; Nakagawa, Yuuki; Takahashi, Yukari; Hotta, Yunhong; Yasunaga, Jun-ichirou; Matsuoka, Masao; Hastings, Michael H.; Kiyonari, Hiroshi; Okamura, Hitoshi

    2016-01-01

    G-protein-coupled receptors (GPCRs) participate in a broad range of physiological functions. A priority for fundamental and clinical research, therefore, is to decipher the function of over 140 remaining orphan GPCRs. The suprachiasmatic nucleus (SCN), the brain's circadian pacemaker, governs daily rhythms in behaviour and physiology. Here we launch the SCN orphan GPCR project to (i) search for murine orphan GPCRs with enriched expression in the SCN, (ii) generate mutant animals deficient in candidate GPCRs, and (iii) analyse the impact on circadian rhythms. We thereby identify Gpr176 as an SCN-enriched orphan GPCR that sets the pace of circadian behaviour. Gpr176 is expressed in a circadian manner by SCN neurons, and molecular characterization reveals that it represses cAMP signalling in an agonist-independent manner. Gpr176 acts independently of, and in parallel to, the Vipr2 GPCR, not through the canonical Gi, but via the unique G-protein subclass Gz. PMID:26882873

  14. Laboratory Investigations of the Hydro-Mechanical-Chemical Coupling Behaviour of Sandstone in CO2 Storage in Aquifers

    NASA Astrophysics Data System (ADS)

    Zhou, Hui; Hu, Dawei; Zhang, Fan; Shao, Jianfu; Feng, Xiating

    2016-02-01

    This paper is devoted to experimental investigations of the hydro-mechanical-chemical coupling behaviour of sandstone in the context of CO2 storage in aquifers. We focused on the evolution of creep strain, the transport properties and the elastic modulus of sandstone under the effect of CO2-brine or CO2 alone. A summary of previous laboratory results is first presented, including mechanical, poromechanical and hydro-mechanical-chemical coupling properties. Tests were then performed to investigate the evolution of the creep strain and permeability during the injection of CO2-brine or CO2 alone. After the injection of CO2-brine or CO2 alone, an instantaneous volumetric dilatancy was observed due to the decrease in the effective confining stress. However, CO2 alone had a significant influence on the creep strain and permeability compared to the small influence of CO2-brine. This phenomenon can be attributed to the acceleration of the CO2-brine-rock reaction by the generation of carbonic acid induced by the dissolution of CO2 into the brine. The original indentation tests on samples after the CO2-brine-rock reaction were also performed and indicated that the elastic modulus decreased with an increasing reaction time. The present laboratory results can advance our knowledge of the hydro-mechanical-chemical coupling behaviour of sandstone in CO2 storage in aquifers.

  15. Temperature-induced electronsbnd phonon coupling behaviour of AgGaS2 probed by Brillouin spectroscopy

    NASA Astrophysics Data System (ADS)

    Kavitha, C.; Narayana, Chandrabhas

    2014-10-01

    Low-temperature Brillouin scattering studies on Chalcopyrite AgGaS2 have been carried out between the temperatures ranges 20sbnd 300 K. We observe the Brillouin modes for AgGaS2 as follows: for crossed polarization (VH) the two modes are around 5.4 and 18 GHz, labelled as RSW1 (Rayleigh surface mode), LA (longitudinal) modes and for parallel polarization (HH), we see the modes are around 4.5 and 11 GHz, labelled as RSW2, TA (transverse acoustic). According to this acoustic phonon mode behaviour with temperature, we do see phase transition at 80 K for AgGaS2. The phase change observed at 80 K is attributed to a strong electronsbnd phonon coupling between the acoustic modes, which modulates the acoustic mode frequency 10sbnd 15%. The strong electronsbnd phonon coupling between acoustic modes (LA and TA), which is seen from the anomalous behaviour below 80 K, shows the electronic transition to be of the type direct to indirect band gap. The sound velocity and elastic constants have been calculated using Brillouin modes, which are in good agreement with previous reports.

  16. Nonlinear dynamic behaviour of a rotor-foundation system coupled through passive magnetic bearings with magnetic anisotropy - Theory and experiment

    NASA Astrophysics Data System (ADS)

    Enemark, Søren; Santos, Ilmar F.

    2016-02-01

    In this work, the nonlinear dynamic behaviour of a vertical rigid rotor interacting with a flexible foundation by means of two passive magnetic bearings is quantified and evaluated. The quantification is based on theoretical and experimental investigation of the non-uniformity (anisotropy) of the magnetic field and the weak nonlinearity of the magnetic forces. Through mathematical modelling the nonlinear equations of motion are established for describing the shaft and bearing housing lateral dynamics coupled via the nonlinear and non-uniform magnetic forces. The equations of motion are solved in the frequency domain by the methods of Finite Difference and pseudo-arclength continuation. The theoretical findings are validated against experiments carried out using a dedicated test-rig and a special device for characterisation of the magnetic anisotropy. The characterisation of the magnetic anisotropy shows that it can be quantified as magnetic eccentricities having an amplitude and a phase, which result in linear and parametric excitation. The magnetic eccentricities are also determined using the steady-state response of the rotor-bearing system due to forcing from the magnetic anisotropies and several levels of mass imbalance. Discrepancies in the results from the two methods in terms of magnetic eccentricity magnitude are due to additional geometric eccentricities in the shaft. The steady-state system response shows clear nonlinear phenomena, e.g. bent resonance peaks, jump phenomena and nonlinear cross-coupling between the two orthogonal directions, especially during counter-phase motion between shaft and bearings. The clear nonlinear behaviour is facilitated by the lack of damping resulting in relatively large vibrations. The overall nonlinear dynamic behaviour is well captured by the theoretical model, thereby validating the modelling approach.

  17. Model coupling methodology for thermo-hydro-mechanical-chemical numerical simulations in integrated assessment of long-term site behaviour

    NASA Astrophysics Data System (ADS)

    Kempka, Thomas; De Lucia, Marco; Kühn, Michael

    2015-04-01

    The integrated assessment of long-term site behaviour taking into account a high spatial resolution at reservoir scale requires a sophisticated methodology to represent coupled thermal, hydraulic, mechanical and chemical processes of relevance. Our coupling methodology considers the time-dependent occurrence and significance of multi-phase flow processes, mechanical effects and geochemical reactions (Kempka et al., 2014). Hereby, a simplified hydro-chemical coupling procedure was developed (Klein et al., 2013) and validated against fully coupled hydro-chemical simulations (De Lucia et al., 2015). The numerical simulation results elaborated for the pilot site Ketzin demonstrate that mechanical reservoir, caprock and fault integrity are maintained during the time of operation and that after 10,000 years CO2 dissolution is the dominating trapping mechanism and mineralization occurs on the order of 10 % to 25 % with negligible changes to porosity and permeability. De Lucia, M., Kempka, T., Kühn, M. A coupling alternative to reactive transport simulations for long-term prediction of chemical reactions in heterogeneous CO2 storage systems (2014) Geosci Model Dev Discuss 7:6217-6261. doi:10.5194/gmdd-7-6217-2014. Kempka, T., De Lucia, M., Kühn, M. Geomechanical integrity verification and mineral trapping quantification for the Ketzin CO2 storage pilot site by coupled numerical simulations (2014) Energy Procedia 63:3330-3338, doi:10.1016/j.egypro.2014.11.361. Klein E, De Lucia M, Kempka T, Kühn M. Evaluation of longterm mineral trapping at the Ketzin pilot site for CO2 storage: an integrative approach using geo-chemical modelling and reservoir simulation. Int J Greenh Gas Con 2013; 19:720-730. doi:10.1016/j.ijggc.2013.05.014.

  18. Behaviour of plate anchorage in plate-reinforced composite coupling beams.

    PubMed

    Lam, W Y; Li, Lingzhi; Su, R K L; Pam, H J

    2013-01-01

    As a new alternative design, plate-reinforced composite (PRC) coupling beam achieves enhanced strength and ductility by embedding a vertical steel plate into a conventionally reinforced concrete (RC) coupling beam. Based on a nonlinear finite element model developed in the authors' previous study, a parametric study presented in this paper has been carried out to investigate the influence of several key parameters on the overall performance of PRC coupling beams. The effects of steel plate geometry, span-to-depth ratio of beams, and steel reinforcement ratios at beam spans and in wall regions are quantified. It is found that the anchorage length of the steel plate is primarily controlled by the span-to-depth ratio of the beam. Based on the numerical results, a design curve is proposed for determining the anchorage length of the steel plate. The load-carrying capacity of short PRC coupling beams with high steel ratio is found to be controlled by the steel ratio of wall piers. The maximum shear stress of PRC coupling beams should be limited to 15 MPa. PMID:24288465

  19. Behaviour of Plate Anchorage in Plate-Reinforced Composite Coupling Beams

    PubMed Central

    Lam, W. Y.; Li, Lingzhi; Su, R. K. L.; Pam, H. J.

    2013-01-01

    As a new alternative design, plate-reinforced composite (PRC) coupling beam achieves enhanced strength and ductility by embedding a vertical steel plate into a conventionally reinforced concrete (RC) coupling beam. Based on a nonlinear finite element model developed in the authors' previous study, a parametric study presented in this paper has been carried out to investigate the influence of several key parameters on the overall performance of PRC coupling beams. The effects of steel plate geometry, span-to-depth ratio of beams, and steel reinforcement ratios at beam spans and in wall regions are quantified. It is found that the anchorage length of the steel plate is primarily controlled by the span-to-depth ratio of the beam. Based on the numerical results, a design curve is proposed for determining the anchorage length of the steel plate. The load-carrying capacity of short PRC coupling beams with high steel ratio is found to be controlled by the steel ratio of wall piers. The maximum shear stress of PRC coupling beams should be limited to 15 MPa. PMID:24288465

  20. An experimental evaluation of the fully coupled hysteretic electro-mechanical behaviour of piezoelectric actuators

    NASA Astrophysics Data System (ADS)

    Butcher, Mark; Davino, Daniele; Giustiniani, Alessandro; Masi, Alessandro

    2016-04-01

    Piezoelectrics are the most commonly used of the multifunctional smart materials in industrial applications, because of their relatively low cost and ease of use in electric and electronic oriented applications. Nevertheless, while datasheets usually give just small signal quasi-static parameters, their full potential can only be exploited only if a full characterization is available because the maximum stroke or the higher piezo coupling coefficients are available at different electro-mechanical biases, where often small signal analysis is not valid. In this paper a method to get the quasi-static fully coupled characterization is presented. The method is tested on a commercial piezo actuator but can be extended to similar devices.

  1. Coupling system dynamics and contact behaviour: Modelling bearings subjected to environmental induced vibrations and ‘false brinelling’ degradation

    NASA Astrophysics Data System (ADS)

    Massi, Francesco; Rocchi, J.; Culla, A.; Berthier, Y.

    2010-05-01

    During the last decades the increase in power of mechanical systems and the demand for increasing service life leads mechanical components of a system to work in extreme conditions. Moreover, actual mechanical systems include surfaces in sliding contact that are subjected to wear if exposed to high vibration. In fact, the vibration of components in contact results in large oscillations of the local contact stresses, due to the local deformation of the components at the contact interfaces. To approach correctly tribological problems, the coupling between the scale of the mechanism (system dynamics) and the scale of the contact needs to be accounted for. This paper presents an analysis concerning the influence of the vibrations induced by aircraft engines on the contact stresses of rolling bearings of the bleed system valves. To study the wear, resulting from false brinelling at the contact surfaces between balls and races of the bearings, it is then necessary to determine the forces due to the system vibrations and acting at the bearing connections with the structure. In order to perform a numerical transient analysis of the system dynamics a nonlinear simplified model of the valve (mechanism scale) is developed. The model is validated by comparing the numerical results with experimental tests. The time behaviour of the global forces on the bearings, and the respective displacements between the contact surfaces, are then used as inputs for a finite element model of the bearings (contact scale). The model is used to calculate and analyze the behaviour in time of the local contact constraints between race and balls. This analysis, developed in the framework of a European project, is an example of the proposed general approach to contact problems, by coupling the analysis of the mechanism and contact scales.

  2. Magnetism behaviours dominated by the interplay of magnetic anisotropy and exchange coupling in local Co discs.

    PubMed

    Yang, En-Cui; Liu, Zhong-Yi; Zhang, Lei; Yang, Na; Zhao, Xiao-Jun

    2016-05-10

    Disc-like Co core-derived (4,4)- and (3,6)-connected layers, {[Co7(C2H5OH)1.5(H2O)0.5(Hdatrz)2(μ3-OH)4(ip)5]·2.5H2O·C2H5OH}n () and [Co7(H2O)4(ade)2(μ3-OH)6(sip)2]n () (Hdatrz = 3,5-diamino-1,2,4-triazole, ade(-) = adeninate, ip(2-) = isophthalate and sip(3-) = 5-sulfoisophthalate) were solvothermally generated and structurally and magnetically characterized. The effect of magnetic anisotropy and exchange coupling from the local Co cores on the resulting magnetism properties are discussed. A crystallographically asymmetric Co core in exhibited an unusual single-molecule magnet (SMM)-like response under zero dc field resulting from strong anisotropy generated by two different types of Co(II) polyhedra and highly anisotropic exchange interactions. By contrast, a highly symmetric Co disc in belonging to the C2h point group showed only strong ferromagnetic exchange, to lead to an overall ST = 7/2 spin ground-state at low temperature. Thus, the interplay of magnetic anisotropy and exchange coupling has a great and complicated influence on the overall magnetic phenomena, which should be fully considered for the design and preparation of new Co(II)-SMMs.

  3. Magnetism behaviours dominated by the interplay of magnetic anisotropy and exchange coupling in local Co discs.

    PubMed

    Yang, En-Cui; Liu, Zhong-Yi; Zhang, Lei; Yang, Na; Zhao, Xiao-Jun

    2016-05-10

    Disc-like Co core-derived (4,4)- and (3,6)-connected layers, {[Co7(C2H5OH)1.5(H2O)0.5(Hdatrz)2(μ3-OH)4(ip)5]·2.5H2O·C2H5OH}n () and [Co7(H2O)4(ade)2(μ3-OH)6(sip)2]n () (Hdatrz = 3,5-diamino-1,2,4-triazole, ade(-) = adeninate, ip(2-) = isophthalate and sip(3-) = 5-sulfoisophthalate) were solvothermally generated and structurally and magnetically characterized. The effect of magnetic anisotropy and exchange coupling from the local Co cores on the resulting magnetism properties are discussed. A crystallographically asymmetric Co core in exhibited an unusual single-molecule magnet (SMM)-like response under zero dc field resulting from strong anisotropy generated by two different types of Co(II) polyhedra and highly anisotropic exchange interactions. By contrast, a highly symmetric Co disc in belonging to the C2h point group showed only strong ferromagnetic exchange, to lead to an overall ST = 7/2 spin ground-state at low temperature. Thus, the interplay of magnetic anisotropy and exchange coupling has a great and complicated influence on the overall magnetic phenomena, which should be fully considered for the design and preparation of new Co(II)-SMMs. PMID:27089955

  4. The Interdependence of Adult Relationship Quality and Parenting Behaviours among African American and European Couples in Rural, Low-Income Communities

    PubMed Central

    Zvara, Bharathi J.; Mills-Koonce, W. Roger; Heilbron, Nicole; Clincy, Amanda; Cox, Martha J.

    2015-01-01

    The present study extends the spillover and crossover hypotheses to more carefully model the potential interdependence between parent–parent interaction quality and parent–child interaction quality in family systems. Using propensity score matching, the present study attempted to isolate family processes that are unique across African American and European American couples that are independent of other socio-demographic factors to further clarify how interparental relationships may be related to parenting in a rural, low-income sample. The Actor–Partner Interdependence Model (APIM), a statistical analysis technique that accounts for the interdependence of relationship data, was used with a sample of married and non-married cohabiting African American and European American couples (n = 82 dyads) to evaluate whether mothers' and fathers' observed parenting behaviours are related to their behaviours and their partner's behaviours observed in a couple problem-solving interaction. Findings revealed that interparental withdrawal behaviour, but not conflict behaviour, was associated with less optimal parenting for fathers but not mothers, and specifically so for African American fathers. Our findings support the notion of interdependence across subsystems within the family and suggest that African American fathers may be specifically responsive to variations in interparental relationship quality. PMID:26430390

  5. COUPLING

    DOEpatents

    Frisch, E.; Johnson, C.G.

    1962-05-15

    A detachable coupling arrangement is described which provides for varying the length of the handle of a tool used in relatively narrow channels. The arrangement consists of mating the key and keyhole formations in the cooperating handle sections. (AEC)

  6. A simple behaviour provides accuracy and flexibility in odour plume tracking--the robotic control of sensory-motor coupling in silkmoths.

    PubMed

    Ando, Noriyasu; Kanzaki, Ryohei

    2015-12-01

    Odour plume tracking is an essential behaviour for animal survival. A fundamental strategy for this is to move upstream and then across-stream. Male silkmoths, Bombyx mori, display this strategy as a pre-programmed sequential behaviour. They walk forward (surge) in response to the female sex pheromone and perform a zigzagging 'mating dance'. Though pre-programmed, the surge direction is modulated by bilateral olfactory input and optic flow. However, the nature of the interaction between these two sensory modalities and contribution of the resultant motor command to localizing an odour source are still unknown. We evaluated the ability of the silkmoth to localize an odour source under conditions of disturbed sensory-motor coupling, using a silkmoth-driven mobile robot. The significance of the bilateral olfaction of the moth was confirmed by inverting the olfactory input to the antennae, or its motor output. Inversion of the motor output induced consecutive circling, which was inhibited by covering the visual field of the moth. This suggests that the corollary discharge from the motor command and the reafference of self-generated optic flow generate compensatory signals to guide the surge accurately. Additionally, after inverting the olfactory input, the robot successfully tracked the odour plume by using a combination of behaviours. These results indicate that accurate guidance of the reflexive surge by integrating bilateral olfactory and visual information with innate pre-programmed behaviours increases the flexibility to track an odour plume even under disturbed circumstances. PMID:26486361

  7. Effect of thermo-coupled processes on the behaviour of a clay barrier submitted to heating and hydration.

    PubMed

    Sánchez, Marcelo; Gens, Antonio; Olivella, Sebastia

    2010-03-01

    The storage of high level radioactive waste is still an unresolved problem of the nuclear industry, being geological disposal the most favoured option and, naturally, the one requiring the strongest geo-mechanical input. Most conceptual designs for the deep geological disposal of nuclear waste envisage placing the canisters containing the waste in horizontal drifts or vertical boreholes. The empty space surrounding the canisters is filled by an engineered barrier often made up of compacted swelling clay. In the barrier and the near field, significant thermo-hydro-mechanical(THM) phenomena take place that interact in a complex way. A good understanding of THM issues is, therefore, necessary to ensure a correct performance of engineered barriers and seals. The conditions of the bentonite in an engineered barrier for high-level radioactive waste disposal are being simulated in a mock-up heating test at almost scale, at the premises of CIEMAT in Madrid. The evolution of the main Thermo-Hydro-Mechanical (THM) variables of this test are analysed in this paper by using a fully coupled THM formulation and the corresponding finite element code. Special emphasis has been placed on the study of the effect of thermo-osmotic flow in the hydration of the clay barrier at an advanced staged of the experiment. PMID:20209250

  8. Chemo-mechanics of salt damage in stone.

    PubMed

    Flatt, Robert J; Caruso, Francesco; Sanchez, Asel Maria Aguilar; Scherer, George W

    2014-01-01

    Many porous materials are damaged by pressure exerted by salt crystals growing in their pores. This is a serious issue in conservation science, geomorphology, geotechnical engineering and concrete materials science. In all cases, a central question is whether crystallization pressure will cause damage. Here we present an experiment in which the crystallization pressure and the pore saturation are varied in a controlled way. We demonstrate that a strain energy failure criterion can be used to predict when damage will occur. The experiment considered is the most widely used means to study the susceptibility to salt crystallization, so quantification of this test has far-reaching implications. PMID:25208600

  9. Achieving synchronization with active hybrid materials: Coupling self-oscillating gels and piezoelectric films

    NASA Astrophysics Data System (ADS)

    Yashin, Victor V.; Levitan, Steven P.; Balazs, Anna C.

    Our goal is to develop materials that compute by using non-linear oscillating chemical reactions to perform spatio-temporal recognition tasks. The material of choice is a polymer gel undergoing the oscillatory Belousov-Zhabotinsky reaction. The novelty of our approach is in employing hybrid gel-piezoelectric micro-electro-mechanical systems (MEMS) to couple local chemo-mechanical oscillations over long distances by electrical connection. Our modeling revealed that (1) interaction between the MEMS units is sufficiently strong for synchronization; (2) the mode of synchronization depends on the number of units, type of circuit connection (serial of parallel), and polarity of the units; (3) each mode has a distinctive pattern in phase of oscillations and generated voltage. The results indicate feasibility of using the hybrid gel-piezoelectric MEMS for oscillator based unconventional computing.

  10. A coupled mechanical and chemical damage model for concrete affected by alkali–silica reaction

    SciTech Connect

    Pignatelli, Rossella; Comi, Claudia; Monteiro, Paulo J.M.

    2013-11-15

    To model the complex degradation phenomena occurring in concrete affected by alkali–silica reaction (ASR), we formulate a poro-mechanical model with two isotropic internal variables: the chemical and the mechanical damage. The chemical damage, related to the evolution of the reaction, is caused by the pressure generated by the expanding ASR gel on the solid concrete skeleton. The mechanical damage describes the strength and stiffness degradation induced by the external loads. As suggested by experimental results, degradation due to ASR is considered to be localized around reactive sites. The effect of the degree of saturation and of the temperature on the reaction development is also modeled. The chemical damage evolution is calibrated using the value of the gel pressure estimated by applying the electrical diffuse double-layer theory to experimental values of the surface charge density in ASR gel specimens reported in the literature. The chemo-damage model is first validated by simulating expansion tests on reactive specimens and beams; the coupled chemo-mechanical damage model is then employed to simulate compression and flexure tests results also taken from the literature. -- Highlights: •Concrete degradation due to ASR in variable environmental conditions is modeled. •Two isotropic internal variables – chemical and mechanical damage – are introduced. •The value of the swelling pressure is estimated by the diffuse double layer theory. •A simplified scheme is proposed to relate macro- and microscopic properties. •The chemo-mechanical damage model is validated by simulating tests in literature.

  11. Achieving synchronization with active hybrid materials: Coupling self-oscillating gels and piezoelectric films.

    PubMed

    Yashin, Victor V; Levitan, Steven P; Balazs, Anna C

    2015-06-24

    Lightweight, deformable materials that can sense and respond to human touch and motion can be the basis of future wearable computers, where the material itself will be capable of performing computations. To facilitate the creation of "materials that compute", we draw from two emerging modalities for computation: chemical computing, which relies on reaction-diffusion mechanisms to perform operations, and oscillatory computing, which performs pattern recognition through synchronization of coupled oscillators. Chemical computing systems, however, suffer from the fact that the reacting species are coupled only locally; the coupling is limited by diffusion as the chemical waves propagate throughout the system. Additionally, oscillatory computing systems have not utilized a potentially wearable material. To address both these limitations, we develop the first model for coupling self-oscillating polymer gels to a piezoelectric (PZ) micro-electro-mechanical system (MEMS). The resulting transduction between chemo-mechanical and electrical energy creates signals that can be propagated quickly over long distances and thus, permits remote, non-diffusively coupled oscillators to communicate and synchronize. Moreover, the oscillators can be organized into arbitrary topologies because the electrical connections lift the limitations of diffusive coupling. Using our model, we predict the synchronization behavior that can be used for computational tasks, ultimately enabling "materials that compute".

  12. Achieving synchronization with active hybrid materials: Coupling self-oscillating gels and piezoelectric films

    NASA Astrophysics Data System (ADS)

    Yashin, Victor V.; Levitan, Steven P.; Balazs, Anna C.

    2015-06-01

    Lightweight, deformable materials that can sense and respond to human touch and motion can be the basis of future wearable computers, where the material itself will be capable of performing computations. To facilitate the creation of “materials that compute”, we draw from two emerging modalities for computation: chemical computing, which relies on reaction-diffusion mechanisms to perform operations, and oscillatory computing, which performs pattern recognition through synchronization of coupled oscillators. Chemical computing systems, however, suffer from the fact that the reacting species are coupled only locally; the coupling is limited by diffusion as the chemical waves propagate throughout the system. Additionally, oscillatory computing systems have not utilized a potentially wearable material. To address both these limitations, we develop the first model for coupling self-oscillating polymer gels to a piezoelectric (PZ) micro-electro-mechanical system (MEMS). The resulting transduction between chemo-mechanical and electrical energy creates signals that can be propagated quickly over long distances and thus, permits remote, non-diffusively coupled oscillators to communicate and synchronize. Moreover, the oscillators can be organized into arbitrary topologies because the electrical connections lift the limitations of diffusive coupling. Using our model, we predict the synchronization behavior that can be used for computational tasks, ultimately enabling “materials that compute”.

  13. Achieving synchronization with active hybrid materials: Coupling self-oscillating gels and piezoelectric films.

    PubMed

    Yashin, Victor V; Levitan, Steven P; Balazs, Anna C

    2015-01-01

    Lightweight, deformable materials that can sense and respond to human touch and motion can be the basis of future wearable computers, where the material itself will be capable of performing computations. To facilitate the creation of "materials that compute", we draw from two emerging modalities for computation: chemical computing, which relies on reaction-diffusion mechanisms to perform operations, and oscillatory computing, which performs pattern recognition through synchronization of coupled oscillators. Chemical computing systems, however, suffer from the fact that the reacting species are coupled only locally; the coupling is limited by diffusion as the chemical waves propagate throughout the system. Additionally, oscillatory computing systems have not utilized a potentially wearable material. To address both these limitations, we develop the first model for coupling self-oscillating polymer gels to a piezoelectric (PZ) micro-electro-mechanical system (MEMS). The resulting transduction between chemo-mechanical and electrical energy creates signals that can be propagated quickly over long distances and thus, permits remote, non-diffusively coupled oscillators to communicate and synchronize. Moreover, the oscillators can be organized into arbitrary topologies because the electrical connections lift the limitations of diffusive coupling. Using our model, we predict the synchronization behavior that can be used for computational tasks, ultimately enabling "materials that compute". PMID:26105979

  14. Achieving synchronization with active hybrid materials: Coupling self-oscillating gels and piezoelectric films

    PubMed Central

    Yashin, Victor V.; Levitan, Steven P.; Balazs, Anna C.

    2015-01-01

    Lightweight, deformable materials that can sense and respond to human touch and motion can be the basis of future wearable computers, where the material itself will be capable of performing computations. To facilitate the creation of “materials that compute”, we draw from two emerging modalities for computation: chemical computing, which relies on reaction-diffusion mechanisms to perform operations, and oscillatory computing, which performs pattern recognition through synchronization of coupled oscillators. Chemical computing systems, however, suffer from the fact that the reacting species are coupled only locally; the coupling is limited by diffusion as the chemical waves propagate throughout the system. Additionally, oscillatory computing systems have not utilized a potentially wearable material. To address both these limitations, we develop the first model for coupling self-oscillating polymer gels to a piezoelectric (PZ) micro-electro-mechanical system (MEMS). The resulting transduction between chemo-mechanical and electrical energy creates signals that can be propagated quickly over long distances and thus, permits remote, non-diffusively coupled oscillators to communicate and synchronize. Moreover, the oscillators can be organized into arbitrary topologies because the electrical connections lift the limitations of diffusive coupling. Using our model, we predict the synchronization behavior that can be used for computational tasks, ultimately enabling “materials that compute”. PMID:26105979

  15. Coupling granular activated carbon adsorption with membrane bioreactor treatment for trace organic contaminant removal: breakthrough behaviour of persistent and hydrophilic compounds.

    PubMed

    Nguyen, Luong N; Hai, Faisal I; Kang, Jinguo; Price, William E; Nghiem, Long D

    2013-04-15

    This study investigated the removal of trace organic contaminants by a combined membrane bioreactor - granular activated carbon (MBR-GAC) system over a period of 196 days. Of the 22 compounds investigated here, all six hydrophilic compounds with electron-withdrawing functional groups (i.e., metronidazole, carbamazepine, ketoprofen, naproxen, fenoprop and diclofenac) exhibited very low removal efficiency by MBR-only treatment. GAC post-treatment initially complemented MBR treatment very well; however, a compound-specific gradual deterioration of the removal of the above-mentioned problematic compounds was noted. While a 20% breakthrough of all four negatively charged compounds namely ketoprofen, naproxen, fenoprop and diclofenac occurred within 1000-3000 bed volumes (BV), the same level of breakthrough of the two neutral compounds metronidazole and carbamazepine did not occur until 11,000 BV. Single-solute isotherm parameters did not demonstrate any discernible correlation individually with any of the parameters that may govern adsorption onto GAC, such as log D, number of hydrogen-bond donor/acceptor groups, dipole moment or aromaticity ratio of the compounds. The isotherm data, however, could differentiate the breakthrough behaviour between negatively charged and neutral trace organic contaminants.

  16. Rotor dynamic behaviour of a high-speed oil-free motor compressor with a rigid coupling supported on four radial magnetic bearings

    NASA Technical Reports Server (NTRS)

    Schmied, J.; Pradetto, J. C.

    1994-01-01

    The combination of a high-speed motor, dry gas seals, and magnetic bearings realized in this unit facilitates the elimination of oil. The motor is coupled with a quill shaft to the compressor. This yields higher natural frequencies of the rotor than with the use of a diaphragm coupling and helps to maintain a sufficient margin of the maximum speed to the frequency of the second compressor bending mode. However, the controller of each bearing then has to take the combined modes of both machines into account. The requirements for the controller to ensure stability and sufficient damping of all critical speeds are designed and compared with the implemented controller. The calculated closed loop behavior was confirmed experimentally, except the stability of some higher modes due to slight frequency deviations of the rotor model to the actual rotor. The influence of a mechanical damper as a device to provide additional damping to high models is demonstrated theoretically. After all, it was not necessary to install the damper, since all modes cold be stabilized by the controller.

  17. Modelling real disease dynamics with behaviourally adaptive complex networks. Comment on "Coupled disease-behavior dynamics on complex networks: A review" by Z. Wang et al.

    NASA Astrophysics Data System (ADS)

    Small, Michael

    2015-12-01

    Mean field compartmental models of disease transmission have been successfully applied to a host of different scenarios, and the Kermack-McKendrick equations are now a staple of mathematical biology text books. In Susceptible-Infected-Removed format these equations provide three coupled first order ordinary differential equations with a very mild nonlinearity and they are very well understood. However, underpinning these equations are two important assumptions: that the population is (a) homogeneous, and (b) well-mixed. These assumptions become closest to being true for diseases infecting a large portion of the population for which inevitable individual effects can be averaged away. Emerging infectious disease (such as, in recent times, SARS, avian influenza, swine flu and ebola) typically does not conform to this scenario. Individual contacts and peculiarities of the transmission network play a vital role in understanding the dynamics of such relatively rare infections - particularly during the early stages of an outbreak.

  18. Qualitative and quantitative characterization of the arsenic-binding behaviour of sulfur-containing peptides and proteins by the coupling of reversed phase liquid chromatography to electrospray ionization mass spectrometry.

    PubMed

    Schmidt, Anne-Christine; Mickein, Kathleen

    2012-08-01

    Phenylarsenic-substituted cysteine-containing peptides and proteins were completely differentiated from their unbound original forms by the coupling of reversed phase liquid chromatography with electrospray ionization mass spectrometry. The analysis of biomolecules possessing structure-stabilizing disulfide bridges after reduction provides new insights into requirements concerning the accessibility of cysteine residues for reducing agents as well as for arsenic compounds in a spatial protein structure. Complementary binding studies performed using direct ESI-MS without chromatographic coupling in different solvent systems demonstrated that more than one binding site were activated for aprotinin and lysozyme in denaturing solvents because of a stronger defolding. From the intensities of the different charge states occurring in the mass spectra as well as from the LC elution behaviour, it can be deduced that the folding state of the arsenic-bound protein species resembles the native, oxidized conformation. In contrast, although the milk protein α-lactalbumin has several disulfide bridges, only one phenylarsenic moiety was bound under strongly denaturing conditions. Because of the charge state distribution in the ESI mass spectra, a conformational change to a molten globule structure is assumed. For the second considered milk protein ß-lactoglobulin, a noncovalent interaction with phenylarsine oxide was detected. In general, smaller apparent binding constants for the condensation reactions of the biomolecules with phenylarsine oxide leading to covalent arsenic-sulfur bindings were determined from direct injection ESI-MS measurements than from LC-ESI-MS coupling. The following order of binding affinities for one phenylarsenic group can be assumed from both ESI-MS and LC-ESI-MS: nonapeptide vasopressin > nonapeptide vasotocin > lysozyme > aprotinin > α-lactalbumin > thioredoxin. Kinetic investigations by LC-ESI-MS yielded a partial reaction order

  19. Multiple-Code BenchMaek Simulation Stidy of Coupled THMC Processes IN the EXCAVATION DISTURBED ZONE Associated with Geological Nuclear Waste Repositories

    SciTech Connect

    J. Rutqvist; X. Feng; J. Hudson; L. Jing; A. Kobayashi; T. Koyama; P.Pan; H. Lee; M. Rinne; E. Sonnenthal; Y. Yamamoto

    2006-05-08

    An international, multiple-code benchmark test (BMT) study is being conducted within the international DECOVALEX project to analyze coupled thermal, hydrological, mechanical and chemical (THMC) processes in the excavation disturbed zone (EDZ) around emplacement drifts of a nuclear waste repository. This BMT focuses on mechanical responses and long-term chemo-mechanical effects that may lead to changes in mechanical and hydrological properties in the EDZ. This includes time-dependent processes such as creep, and subcritical crack, or healing of fractures that might cause ''weakening'' or ''hardening'' of the rock over the long term. Five research teams are studying this BMT using a wide range of model approaches, including boundary element, finite element, and finite difference, particle mechanics, and elasto-plastic cellular automata methods. This paper describes the definition of the problem and preliminary simulation results for the initial model inception part, in which time dependent effects are not yet included.

  20. Ferromagnetic coupling and spin canting behaviour in heterobimetallic Re(IV)M(II/III) (M = Co(II/III), Ni(II)) species.

    PubMed

    Martínez-Lillo, José; Armentano, Donatella; De Munno, Giovanni; Julve, Miguel; Lloret, Francesc; Faus, Juan

    2013-02-01

    Three novel heterobimetallic Re(IV) compounds of formulae [ReBr(4)(μ-ox)M(4,7-Cl(2)phen)(2)]·CH(3)CN·CH(3)NO(2) [M = Co(II) (1) and Ni(II) (2)] and [ReBr(4)(ox)](3)[Co(III)(5,6-dmphen)(3)](2)·CH(3)CN·2CH(3)NO(2)·4H(2)O (3) [ox = oxalate, 4,7-Cl(2)phen = 4,7-dichloro-1,10-phenanthroline and 5,6-dmphen = 5,6-dimethyl-1,10-phenanthroline] have been synthesised and the structures of 1 and 3 determined by single crystal X-ray diffraction. Compound 1 is an oxalato-bridged Re(IV)Co(II) heterodinuclear complex where the [ReBr(4)(ox)](2-) unit acts as a bidentate ligand towards the [Co(4,7-Cl(2)phen)(2)](2+) entity, the separation between Re(IV) and Co(II) across the oxalate being 5.482(1) Å. Compound 3 is an ionic salt whose structure is made up of [Re(IV)Br(4)(ox)](2-) anions and [Co(III)(5,6-dmphen)(3)](3+) cations plus acetonitrile, nitromethane and water as solvent molecules. The magnetic properties of 1-3 were investigated in the temperature range 1.9-300 K. Relatively large ferromagnetic interactions between Re(IV) and M(II) through the bis(bidentate) oxalato occur in 1 and 2 [J(ReM) = +11.0 (1) and +12.2 cm(-1) (2), the Hamiltonian being defined as Ĥ = -J(ReM)Ŝ(Re)·Ŝ(M)] which are explained on the basis of orbital symmetry considerations. A behaviour typical of a magnetically diluted Re(IV) complex with a large and positive value of zero-field splitting for the ground level (D(Re) = +43 cm(-1)) is observed for 3 in the high temperature range, whereas it exhibits spin canting in the low temperature domain as well as magnetic ordering below ca. 4.8 K.

  1. Surface modification of ZrO2 nanoparticles with styrene coupling agent and its effect on the corrosion behaviour of epoxy coating

    NASA Astrophysics Data System (ADS)

    Zhao, Xia; Liu, Shuan; Wang, Xiutong; Hou, Baorong

    2014-09-01

    The surface of ZrO2 nanoparticles was modified by styrene coupling grafting method to improve the dispersion and interaction of the nanoparticles with the epoxy coating in which the modified ZrO2 nanoparticles were used as an additive. The grafting performance and microstructure of the nano-ZrO2/epoxy coating were analyzed by Fourier transformation infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The corrosion behavior of the nano-ZrO2/epoxy coating on mild steel was evaluated in neutral 3.5 wt% NaCl solution using electrochemical impedance spectroscopy (EIS). Both the coating capacitance and coating resistance fitted by the equivalent circuit from EIS were used to evaluate the protective performance of the coating towards the mild steel. The results show a superior stability and efficient corrosion protection by the modified ZrO2 nanoparticles. The epoxy coating containing 2 wt% modified ZrO2 nanoparticles exhibited the best corrosion performance among all the coating specimens. This research may provide an insight into the protection of mild steel using modified epoxy coatings.

  2. A time-sequence functional analysis of mating behaviour and genital coupling in Drosophila: role of cryptic female choice and male sex-drive in the evolution of male genitalia.

    PubMed

    Jagadeeshan, S; Singh, R S

    2006-07-01

    Male genitalia in Drosophila exemplify strikingly rapid and divergent evolution, whereas female genitalia are relatively invariable. Whereas precopulatory and post-copulatory sexual selection has been invoked to explain this trend, the functional significance of genital structures during copulation remains obscure. We used time-sequence analysis to study the functional significance of external genitalic structures during the course of copulation, between D. melanogaster and D. simulans. This functional analysis has provided new information that reveals the importance of male-driven copulatory mechanics and strategies in the rapid diversification of genitalia. The posterior process, which is a recently evolved sexual character and present only in males of the melanogaster clade, plays a crucial role in mounting as well as in genital coupling. Whereas there is ample evidence for precopulatory and/or post-copulatory female choice, we show here that during copulation there is little or no physical female choice, consequently, males determine copulation duration. We also found subtle differences in copulatory mechanics between very closely related species. We propose that variation in male usage of novel genitalic structures and shifts in copulatory behaviour have played an important role in the diversification of genitalia in species of the Drosophila subgroup.

  3. Capturing poromechanical coupling effects of the reactive fracturing process in porous rock via a DEM-network model

    NASA Astrophysics Data System (ADS)

    Ulven, Ole Ivar; Sun, WaiChing

    2016-04-01

    Fluid transport in a porous medium has important implications for understanding natural geological processes. At a sufficiently large scale, a fluid-saturated porous medium can be regarded as a two-phase continuum, with the fluid constituent flowing in the Darcian regime. Nevertheless, a fluid mediated chemical reaction can in some cases change the permeability of the rock locally: Mineral dissolution can cause increased permeability, whereas mineral precipitation can reduce the permeability. This might trigger a complicated hydro-chemo-mechanical coupling effect that causes channeling of fluids or clogging of the system. If the fluid is injected or produced at a sufficiently high rate, the pressure might increase enough to cause the onset and propagation of fractures. Fractures in return create preferential flow paths that enhance permeability, localize fluid flow and chemical reaction, prevent build-up of pore pressure and cause anisotropy of the hydro-mechanical responses of the effective medium. This leads to a complex coupled process of solid deformation, chemical reaction and fluid transport enhanced by the fracture formation. In this work, we develop a new coupled numerical model to study the complexities of feedback among fluid pressure evolution, fracture formation and permeability changes due to a chemical process in a 2D system. We combine a discrete element model (DEM) previously used to study a volume expanding process[1, 2] with a new fluid transport model based on poroelasticity[3] and a fluid-mediated chemical reaction that changes the permeability of the medium. This provides new insights into the hydro-chemo-mechanical process of a transforming porous medium. References [1] Ulven, O. I., Storheim, H., Austrheim, H., and Malthe-Sørenssen, A. "Fracture Initiation During Volume Increasing Reactions in Rocks and Applications for CO2 Sequestration", Earth Planet. Sc. Lett. 389C, 2014a, pp. 132 - 142, doi:10.1016/j.epsl.2013.12.039. [2] Ulven, O. I

  4. A staggered approach for the coupling of Cahn-Hilliard type diffusion and finite strain elasticity

    NASA Astrophysics Data System (ADS)

    Areias, P.; Samaniego, E.; Rabczuk, T.

    2016-02-01

    We develop an algorithm and computational implementation for simulation of problems that combine Cahn-Hilliard type diffusion with finite strain elasticity. We have in mind applications such as the electro-chemo-mechanics of lithium ion (Li-ion) batteries. We concentrate on basic computational aspects. A staggered algorithm is proposed for the coupled multi-field model. For the diffusion problem, the fourth order differential equation is replaced by a system of second order equations to deal with the issue of the regularity required for the approximation spaces. Low order finite elements are used for discretization in space of the involved fields (displacement, concentration, nonlocal concentration). Three (both 2D and 3D) extensively worked numerical examples show the capabilities of our approach for the representation of (i) phase separation, (ii) the effect of concentration in deformation and stress, (iii) the effect of strain in concentration, and (iv) lithiation. We analyze convergence with respect to spatial and time discretization and found that very good results are achievable using both a staggered scheme and approximated strain interpolation.

  5. The condensed chromatin fiber: an allosteric chemo-mechanical machine for signal transduction and genome processing

    NASA Astrophysics Data System (ADS)

    Lesne, Annick; Bécavin, Christophe; Victor, Jean–Marc

    2012-02-01

    Allostery is a key concept of molecular biology which refers to the control of an enzyme activity by an effector molecule binding the enzyme at another site rather than the active site (allos = other in Greek). We revisit here allostery in the context of chromatin and argue that allosteric principles underlie and explain the functional architecture required for spacetime coordination of gene expression at all scales from DNA to the whole chromosome. We further suggest that this functional architecture is provided by the chromatin fiber itself. The structural, mechanical and topological features of the chromatin fiber endow chromosomes with a tunable signal transduction from specific (or nonspecific) effectors to specific (or nonspecific) active sites. Mechanical constraints can travel along the fiber all the better since the fiber is more compact and regular, which speaks in favor of the actual existence of the (so-called 30 nm) chromatin fiber. Chromatin fiber allostery reconciles both the physical and biochemical approaches of chromatin. We illustrate this view with two supporting specific examples. Moreover, from a methodological point of view, we suggest that the notion of chromatin fiber allostery is particularly relevant for systemic approaches. Finally we discuss the evolutionary power of allostery in the context of chromatin and its relation to modularity.

  6. Effect of chemo-mechanical disintegration on sludge anaerobic digestion for enhanced biogas production.

    PubMed

    Kavitha, S; Pray, S Saji; Yogalakshmi, K N; Kumar, S Adish; Yeom, Ick-Tae; Banu, J Rajesh

    2016-02-01

    The effect of combined surfactant-dispersion pretreatment on dairy waste activated sludge (WAS) reduction in anaerobic digesters was investigated. The experiments were performed with surfactant, Sodium dodecyl sulfate (SDS) in the range of 0.01 to 0.1 g/g suspended solids (SS) and disperser with rpm of 5000-25,000. The COD (chemical oxygen demand) solubilization, suspended solids reduction, and biogas generation increased for an energy input of 7377 kJ/kg total solids (TS) (12,000 rpm, 0.04 g/g SS, and 30 min) and were found to be 38, 32, and 75 %, higher than that of control. The pretreated sludge improved the performance of semicontinuous anaerobic digesters of 4 L working volume operated at four different SRTs (sludge retention time). SRT of 15 days was found to be appropriate showing 49 and 51 % reduction in SS and volatile solids (VS), respectively. The methane yield of the pretreated sample was observed to be 50 mL/g VS removed which was observed to be comparatively higher than the control (12 mL/g VS removed) at optimal SRT of 15 days. To the best of the authors' knowledge, this study is the first to be reported and not yet been documented in literature.

  7. Geo-Chemo-Mechanical Studies for Permanent CO{sub 2} Storage in Geologic Reservoirs

    SciTech Connect

    Kelemen, Peter; Park, Ah-hyung; Matter, Jurg; Gadikota, Greeshma; Lisabeth, Harrison; Zhu, Wenlu

    2013-09-30

    This two-pronged study investigated the rates and mechanisms of formation of Ca and Mg carbonate minerals via reaction of aqueous fluids with silicate minerals and rocks, and the geomechanical effects of such reactions. The kinetic studies focused on the separation of variables, following from previous studies demonstrating rapid formation of carbonates via reaction of the mineral olivine with aqueous fluids rich in NaHCO{sub 3} (plus KHCO{sub 3} and RbHCO{sub 3}) and NaCl at a high partial pressure of CO{sub 2}. We wished to separate and quantify the effects of NaHCO{sub 3} and NaCl, and to investigate whether bicarbonate-rich, aqueous fluids would also cause rapid formation of carbonates via reaction with other minerals and rocks. Further, we wished to improve upon previous work by adding precise characterization of grain size distributions and surface area, and their changes as a result of reaction. We confirmed previous reports of very rapid olivine carbonation. We found that at a given temperature and CO{sub 2} partial pressure the previously observed rate enhancement in olivine carbonation is due mainly to NaHCO{sub 3}, and not to dissolved NaCl. Further, though reaction of the mineral plagioclase, and two rock compositions, were all faster in the presence of NaHCO{sub 3}-rich fluids, compared with saline and de-ionized water, they were all much slower than reaction of olivine. In the experiments showing the fastest reaction rate, average grain size tended to increase during experiments, presumably due to dissolution of small reactant grains plus growth of product phases on reactant surfaces. Porosity/surface area of grains tended to change with reaction progress, due to the formation of dissolution pits and irregular growth of product phases on reactant grain surfaces. Development of a passivating phase (e.g., a layer of silica) due to incongruent dissolution of solid reactants and/or precipitation of solid products was detected, but was relatively minor and did not have a discernable effect on reaction progress. Geomechanical experiments did not identify pressure-temperature-composition conditions under which porous olivine aggregates undergo reaction driven cracking. Little carbonate formed in these experiments. Though we fulfilled the milestones for this project, a variety of reasons for this remain to be investigated in the future. Reaction of porous olivine aggregates with brines rich in NaHCO{sub 3} caused substantial weakening of samples in compression, due to formation of dissolution pits along olivine-olivine grain boundaries, reducing the solid-solid surface area. A preliminary modeling study funded in part by this grant emphasized potential rate enhancements due to reaction-driven cracking. In related research, not funded by this grant, several additional experimental and modeling studies of reaction-driven cracking are underway.

  8. Pulse-coupled BZ oscillators with unequal coupling strengths.

    PubMed

    Horvath, Viktor; Kutner, Daniel J; Chavis, John T; Epstein, Irving R

    2015-02-14

    Coupled chemical oscillators are usually studied with symmetric coupling, either between identical oscillators or between oscillators whose frequencies differ. Asymmetric connectivity is important in neuroscience, where synaptic strength inequality in neural networks commonly occurs. While the properties of the individual oscillators in some coupled chemical systems may be readily changed, enforcing inequality between the connection strengths in a reciprocal coupling is more challenging. We recently demonstrated a novel way of coupling chemical oscillators, which allows for manipulation of individual connection strengths. Here we study two identical, pulse-coupled Belousov-Zhabotinsky (BZ) oscillators with unequal connection strengths. When the pulse perturbations contain KBr (inhibitor), this system exhibits simple out-of-phase and complex oscillations, oscillatory-suppressed states as well as temporally periodic patterns (N : M) in which the two oscillators exhibit different numbers of peaks per cycle. The N : M patterns emerge due to the long-term effect of the inhibitory pulse-perturbations, a feature that has not been considered in earlier works. Time delay was previously shown to have a profound effect on the system's behaviour when pulse coupling was inhibitory and the coupling strengths were equal. When the coupling is asymmetric, however, delay produces no qualitative change in behaviour, though the 1 : 2 temporal pattern becomes more robust. Asymmetry in instantaneous excitatory coupling via AgNO3 injection produces a previously unseen temporal pattern (1 : N patterns starting with a double peak) with time delay and high [AgNO3]. Numerical simulations of the behaviour agree well with theoretical predictions in asymmetrical pulse-coupled systems.

  9. Agoraphobia, compulsive behaviours and behaviour completion mechanisms.

    PubMed

    McConaghy, N

    1983-06-01

    Anxiety is identified with a state of high arousal. Agoraphobia is differentiated from specific phobias which are inherent responses to situations which threatened primitive man. In agoraphobia, attacks of high arousal are produced by situations which delay ongoing activity. It is hypothesised that such delays produce arousal by activating behaviour completion mechanisms. Evidence is reviewed which indicates desensitization has a lasting effect in agoraphobia but not in specific phobias. It is suggested that desensitization reduces the arousal produced by behaviour completion mechanisms. Aversive therapy in homosexuality reduces the subjects' drive to carry out compulsive sexual behaviours but does not alter sexual orientation. It is suggested that compulsive sexual behaviours are not activated by primary sexual drives but by behaviour completion mechanisms which are also responsible for other compulsive behaviours. Aversive therapy acts by reducing the arousal produced by the behaviour completion mechanisms. As both aversive therapy and desensitization reduce such arousal, desensitization should be able to replace aversive therapy in the treatment of compulsive behaviours.

  10. Imitation as behaviour parsing.

    PubMed Central

    Byrne, R W

    2003-01-01

    Non-human great apes appear to be able to acquire elaborate skills partly by imitation, raising the possibility of the transfer of skill by imitation in animals that have only rudimentary mentalizing capacities: in contrast to the frequent assumption that imitation depends on prior understanding of others' intentions. Attempts to understand the apes' behaviour have led to the development of a purely mechanistic model of imitation, the 'behaviour parsing' model, in which the statistical regularities that are inevitable in planned behaviour are used to decipher the organization of another agent's behaviour, and thence to imitate parts of it. Behaviour can thereby be understood statistically in terms of its correlations (circumstances of use, effects on the environment) without understanding of intentions or the everyday physics of cause-and-effect. Thus, imitation of complex, novel behaviour may not require mentalizing, but conversely behaviour parsing may be a necessary preliminary to attributing intention and cause. PMID:12689378

  11. Unintentional behaviour change.

    PubMed

    Aunger, Robert; Curtis, Valerie

    2014-08-01

    We argue that the authors ignore a broad range of possible means of changing behaviour: unintentional change. Most of the behaviours that people seek to change - either in themselves or that are the subject of public health campaigns-are habitual, and hence not necessarily responsive to intentions. An evolutionary approach should take into account all kinds of evolved behavioural responses. PMID:25162861

  12. Changes in the acoustic environment alter the foraging and sheltering behaviour of the cichlid Amititlania nigrofasciata.

    PubMed

    McLaughlin, Kirsty Elizabeth; Kunc, Hansjoerg P

    2015-07-01

    Anthropogenic noise can affect behaviour across a wide range of species in both terrestrial and aquatic environments. However, behaviours might not be affected in isolation. Therefore, a more holistic approach investigating how environmental stressors, such as noise pollution, affect different behaviours in concert is necessary. Using tank-based noise exposure experiments, we tested how changes in the acoustic environment affect the behaviour of the cichlid Amatitlania nigrofasciata. We found that exposure to anthropogenic noise affected a couple of behaviours: an increase in sheltering was accompanied by a decrease in foraging. Our results highlight the multiple negative effects of an environmental stressor on an individual's behaviour.

  13. Genetics of impulsive behaviour

    PubMed Central

    Bevilacqua, Laura; Goldman, David

    2013-01-01

    Impulsivity, defined as the tendency to act without foresight, comprises a multitude of constructs and is associated with a variety of psychiatric disorders. Dissecting different aspects of impulsive behaviour and relating these to specific neurobiological circuits would improve our understanding of the etiology of complex behaviours for which impulsivity is key, and advance genetic studies in this behavioural domain. In this review, we will discuss the heritability of some impulsivity constructs and their possible use as endophenotypes (heritable, disease-associated intermediate phenotypes). Several functional genetic variants associated with impulsive behaviour have been identified by the candidate gene approach and re-sequencing, and whole genome strategies can be implemented for discovery of novel rare and common alleles influencing impulsivity. Via deep sequencing an uncommon HTR2B stop codon, common in one population, was discovered, with implications for understanding impulsive behaviour in both humans and rodents and for future gene discovery. PMID:23440466

  14. Behavioural aspects of terrorism.

    PubMed

    Leistedt, Samuel J

    2013-05-10

    Behavioural and social sciences are useful in collecting and analysing intelligence data, understanding terrorism, and developing strategies to combat terrorism. This article aims to examine the psychopathological concepts of terrorism and discusses the developing roles for behavioural scientists. A systematic review was conducted of studies investigating behavioural aspects of terrorism. These studies were identified by a systematic search of databases, textbooks, and a supplementary manual search of references. Several fundamental concepts were identified that continue to influence the motives and the majority of the behaviours of those who support or engage in this kind of specific violence. Regardless of the psychological aspects and new roles for psychiatrists, the behavioural sciences will continue to be called upon to assist in developing better methods to gather and analyse intelligence, to understand terrorism, and perhaps to stem the radicalisation process.

  15. Helix coupling

    DOEpatents

    Ginell, W.S.

    1989-04-25

    A coupling for connecting helix members in series, which consists of a pair of U-shaped elements, one of which is attached to each helix end with the "U" sections of the elements interlocked. The coupling is particularly beneficial for interconnecting helical Nitinol elements utilized in thermal actuators or engines. Each coupling half is attached to the associated helix at two points, thereby providing axial load while being easily removed from the helix, and reusable.

  16. Helix coupling

    DOEpatents

    Ginell, W.S.

    1982-03-17

    A coupling for connecting helix members in series, which consists of a pair of U-shaped elements, one of which is attached to each helix end with the U sections of the elements interlocked. The coupling is particularly beneficial for interconnecting helical Nitinol elements utilized in thermal actuators or engines. Each coupling half is attached to the associated helix at two points, thereby providing axial load while being easily removed from the helix, and reusable.

  17. Applying One Health to behaviour.

    PubMed

    Bower, Caroline

    2014-11-01

    The British Veterinary Behaviour Association and the Association of Pet Behaviour Counsellors held a meeting last month to highlight the One Health principle with regard to the behaviour of people and animals, particularly pets. Caroline Bower reports. PMID:25377201

  18. Behavioural genetics: An introduction.

    PubMed

    Sluyter, F; Ellenbroek, B A

    1999-06-01

    Behavioural genetics is the study of the hereditary influence on behaviour, and can therefore be regarded as the intersection between behavioural sciences and genetics. As with most other fields of research it is difficult to exactly pinpoint when behavioural genetics started. In fact, one might say that the notion behavioural traits can be inherited may have appeared in human thought as early at 8000 BC, when the domestication of the dog began. The scientific era of behavioural genetics is generally considered to start with Charles Darwin. In his famous book On the Origin of Species by Means of natural Selection, or the Preservation of favoured Races in the Struggle for Life, published in 1859 (and sold out the first day), he devoted an entire chapter on instinctive behavioural patterns. Some years later, in his book The Descent of Man and Selection in Relation to Sex, he clearly stated that the difference between the mind of a human being and the mind of an animal 'is certainly one of degree and not of kind'. Moreover he gave considerable thought that mental powers (and insanity) are heritable aspects.

  19. Suicide and suicidal behaviour.

    PubMed

    Turecki, Gustavo; Brent, David A

    2016-03-19

    Suicide is a complex public health problem of global importance. Suicidal behaviour differs between sexes, age groups, geographic regions, and sociopolitical settings, and variably associates with different risk factors, suggesting aetiological heterogeneity. Although there is no effective algorithm to predict suicide in clinical practice, improved recognition and understanding of clinical, psychological, sociological, and biological factors might help the detection of high-risk individuals and assist in treatment selection. Psychotherapeutic, pharmacological, or neuromodulatory treatments of mental disorders can often prevent suicidal behaviour; additionally, regular follow-up of people who attempt suicide by mental health services is key to prevent future suicidal behaviour.

  20. Early ant trajectories: spatial behaviour before behaviourism.

    PubMed

    Wehner, Rüdiger

    2016-04-01

    In the beginning of the twentieth century, when Jacques Loeb's and John Watson's mechanistic view of life started to dominate animal physiology and behavioural biology, several scientists with different academic backgrounds got engaged in studying the wayfinding behaviour of ants. Largely unaffected by the scientific spirit of the time, they worked independently of each other in different countries: in Algeria, Tunisia, Spain, Switzerland and the United States of America. In the current literature on spatial cognition these early ant researchers--Victor Cornetz, Felix Santschi, Charles Turner and Rudolf Brun--are barely mentioned. Moreover, it is virtually unknown that the great neuroanatomist Santiago Ramón y Cajal had also worked on spatial orientation in ants. This general neglect is certainly due to the fact that nearly all these ant researchers were scientific loners, who did their idiosyncratic investigations outside the realm of comparative physiology, neurobiology and the behavioural sciences of the time, and published their results in French, German, and Spanish at rather inaccessible places. Even though one might argue that much of their work resulted in mainly anecdotal evidence, the conceptual approaches of these early ant researchers preempt much of the present-day discussions on spatial representation in animals. PMID:26898725

  1. Coping behaviour after shipwreck.

    PubMed

    Henderson, S; Bostock, T

    1977-07-01

    A description is given of the coping behaviour of seven men who survived a shipwreck and were not rescued until 13 days later. The principal behaviours shown by the men were attachment ideation, drive to survive, modelling, prayer and hope. Particular attention is paid to the first of these, and consideration given to its likely origins in behavioural evolution. It is proposed as a hitherto inadequately recognized coping behaviour. A follow-up examination 12 to 24 months later showed that five of the seven men available had developed substantial psychiatric disorder, while by contrast one was not only well but claimed to have been enriched by the experience. Exposure to extreme adversity or disaster may have long-term effects on mental health. Further longitudinal studies of disaster victims are necessary for the design of informed after-care.

  2. Psychology: Inducing green behaviour

    NASA Astrophysics Data System (ADS)

    Thøgersen, John

    2013-02-01

    Economic arguments, such as saving money, are often used to promote pro-environmental actions -- for example, reducing energy use. However, research shows that people's environmental motives are sometimes better drivers of behavioural change.

  3. Velocity dependant splash behaviour

    NASA Astrophysics Data System (ADS)

    Hamlett, C. A. E.; Shirtcliffe, N. J.; McHale, G.; Ahn, S.; Doerr, S. H.; Bryant, R.; Newton, M. I.

    2012-04-01

    Extreme soil water repellency can occur in nature via condensation of volatile organic compounds released during wildfires and can lead to increased erosion rate. Such extreme water repellent soil can be classified as superhydrophobic and shares similar chemical and topographical features to specifically designed superhydrophobic surfaces. Previous studies using high speed videography to investigate single droplet impact behaviour on artificial superhydrophobic have revealed three distinct modes of splash behaviour (rebound, pinned and fragmentation) which are dependent on the impact velocity of the droplet. In our studies, using high-speed videography, we show that such splash behaviour can be replicated on fixed 'model' water repellent soils (hydrophobic glass beads/particles). We show that the type of splash behaviour is dependent on both the size and chemical nature of the fixed particles. The particle shape also influences the splash behaviour as shown by drop impact experiments on fixed sand samples. We have also studied soil samples, as collected from the field, which shows that the type of droplet splash behaviour can lead to enhanced soil particle transport.

  4. Nonadiabatic Coupling

    NASA Astrophysics Data System (ADS)

    Kryachko, Eugene S.

    The general features of the nonadiabatic coupling and its relation to molecular properties are surveyed. Some consequences of the [`]equation of motion', formally expressing a [`]smoothness' of a given molecular property within the diabatic basis, are demonstrated. A particular emphasis is made on the relation between a [`]smoothness' of the electronic dipole moment and the generalized Mulliken-Hush formula for the diabatic electronic coupling.

  5. Communication and abnormal behaviour.

    PubMed

    Crown, S

    1979-01-01

    In this paper the similarities between normal and abnormal behaviour are emphasized and selected aspects of communication, normal and aberrant, between persons are explored. Communication in a social system may be verbal or non-verbal: one person's actions cause a response in another person. This response may be cognitive, behavioural or physiological. Communication may be approached through the individual, the social situation or social interaction. Psychoanalysis approaches the individual in terms of the coded communications of psychoneurotic symptoms or psychotic behaviour; the humanist-existential approach is concerned more with emotional expression. Both approaches emphasize the development of individual identity. The interaction between persons and their social background is stressed. Relevant are sociological concepts such as illness behaviour, stigma, labelling, institutionalization and compliance. Two approaches to social interactions are considered: the gamesplaying metaphor, e.g. back pain as a psychosocial manipulation--the 'pain game'; and the 'spiral of reciprocal perspectives' which emphasizes the interactional complexities of social perceptions. Communicatory aspects of psychological treatments are noted: learning a particular metaphor such as 'resolution' of the problem (psychotherapy), learning more 'rewarding' behaviour (learning theory) or learning authenticity or self-actualization (humanist-existential).

  6. Communication and abnormal behaviour.

    PubMed

    Crown, S

    1979-01-01

    In this paper the similarities between normal and abnormal behaviour are emphasized and selected aspects of communication, normal and aberrant, between persons are explored. Communication in a social system may be verbal or non-verbal: one person's actions cause a response in another person. This response may be cognitive, behavioural or physiological. Communication may be approached through the individual, the social situation or social interaction. Psychoanalysis approaches the individual in terms of the coded communications of psychoneurotic symptoms or psychotic behaviour; the humanist-existential approach is concerned more with emotional expression. Both approaches emphasize the development of individual identity. The interaction between persons and their social background is stressed. Relevant are sociological concepts such as illness behaviour, stigma, labelling, institutionalization and compliance. Two approaches to social interactions are considered: the gamesplaying metaphor, e.g. back pain as a psychosocial manipulation--the 'pain game'; and the 'spiral of reciprocal perspectives' which emphasizes the interactional complexities of social perceptions. Communicatory aspects of psychological treatments are noted: learning a particular metaphor such as 'resolution' of the problem (psychotherapy), learning more 'rewarding' behaviour (learning theory) or learning authenticity or self-actualization (humanist-existential). PMID:261653

  7. CO{sub 2} Geologic Storage: Coupled Hydro-Chemo-Thermo-Mechanical Phenomena - From Pore-scale Processes to Macroscale Implications -

    SciTech Connect

    Santamarina, J. Carlos

    2013-05-31

    Global energy consumption will increase in the next decades and it is expected to largely rely on fossil fuels. The use of fossil fuels is intimately related to CO{sub 2} emissions and the potential for global warming. Geological CO{sub 2} storage aims to mitigate the global warming problem by sequestering CO{sub 2} underground. Coupled hydro-chemo-mechanical phenomena determine the successful operation and long term stability of CO{sub 2} geological storage. This research explores coupled phenomena, identifies different zones in the storage reservoir, and investigates their implications in CO{sub 2} geological storage. In particular, the research: Explores spatial patterns in mineral dissolution and precipitation (comprehensive mass balance formulation); experimentally determines the interfacial properties of water, mineral, and CO{sub 2} systems (including CO{sub 2}-water-surfactant mixtures to reduce the CO{sub 2}- water interfacial tension in view of enhanced sweep efficiency); analyzes the interaction between clay particles and CO{sub 2}, and the response of sediment layers to the presence of CO{sub 2} using specially designed experimental setups and complementary analyses; couples advective and diffusive mass transport of species, together with mineral dissolution to explore pore changes during advection of CO{sub 2}-dissolved water along a rock fracture; upscales results to a porous medium using pore network simulations; measures CO{sub 2} breakthrough in highly compacted fine-grained sediments, shale and cement specimens; explores sealing strategies; and experimentally measures CO{sub 2}-CH{sub 4} replacement in hydrate-bearing sediments during. Analytical, experimental and numerical results obtained in this study can be used to identify optimal CO{sub 2} injection and reservoir-healing strategies to maximize the efficiency of CO{sub 2} injection and to attain long-term storage.

  8. A Financial Market Model Incorporating Herd Behaviour.

    PubMed

    Wray, Christopher M; Bishop, Steven R

    2016-01-01

    Herd behaviour in financial markets is a recurring phenomenon that exacerbates asset price volatility, and is considered a possible contributor to market fragility. While numerous studies investigate herd behaviour in financial markets, it is often considered without reference to the pricing of financial instruments or other market dynamics. Here, a trader interaction model based upon informational cascades in the presence of information thresholds is used to construct a new model of asset price returns that allows for both quiescent and herd-like regimes. Agent interaction is modelled using a stochastic pulse-coupled network, parametrised by information thresholds and a network coupling probability. Agents may possess either one or two information thresholds that, in each case, determine the number of distinct states an agent may occupy before trading takes place. In the case where agents possess two thresholds (labelled as the finite state-space model, corresponding to agents' accumulating information over a bounded state-space), and where coupling strength is maximal, an asymptotic expression for the cascade-size probability is derived and shown to follow a power law when a critical value of network coupling probability is attained. For a range of model parameters, a mixture of negative binomial distributions is used to approximate the cascade-size distribution. This approximation is subsequently used to express the volatility of model price returns in terms of the model parameter which controls the network coupling probability. In the case where agents possess a single pulse-coupling threshold (labelled as the semi-infinite state-space model corresponding to agents' accumulating information over an unbounded state-space), numerical evidence is presented that demonstrates volatility clustering and long-memory patterns in the volatility of asset returns. Finally, output from the model is compared to both the distribution of historical stock returns and the market

  9. A Financial Market Model Incorporating Herd Behaviour

    PubMed Central

    2016-01-01

    Herd behaviour in financial markets is a recurring phenomenon that exacerbates asset price volatility, and is considered a possible contributor to market fragility. While numerous studies investigate herd behaviour in financial markets, it is often considered without reference to the pricing of financial instruments or other market dynamics. Here, a trader interaction model based upon informational cascades in the presence of information thresholds is used to construct a new model of asset price returns that allows for both quiescent and herd-like regimes. Agent interaction is modelled using a stochastic pulse-coupled network, parametrised by information thresholds and a network coupling probability. Agents may possess either one or two information thresholds that, in each case, determine the number of distinct states an agent may occupy before trading takes place. In the case where agents possess two thresholds (labelled as the finite state-space model, corresponding to agents’ accumulating information over a bounded state-space), and where coupling strength is maximal, an asymptotic expression for the cascade-size probability is derived and shown to follow a power law when a critical value of network coupling probability is attained. For a range of model parameters, a mixture of negative binomial distributions is used to approximate the cascade-size distribution. This approximation is subsequently used to express the volatility of model price returns in terms of the model parameter which controls the network coupling probability. In the case where agents possess a single pulse-coupling threshold (labelled as the semi-infinite state-space model corresponding to agents’ accumulating information over an unbounded state-space), numerical evidence is presented that demonstrates volatility clustering and long-memory patterns in the volatility of asset returns. Finally, output from the model is compared to both the distribution of historical stock returns and the

  10. A Financial Market Model Incorporating Herd Behaviour.

    PubMed

    Wray, Christopher M; Bishop, Steven R

    2016-01-01

    Herd behaviour in financial markets is a recurring phenomenon that exacerbates asset price volatility, and is considered a possible contributor to market fragility. While numerous studies investigate herd behaviour in financial markets, it is often considered without reference to the pricing of financial instruments or other market dynamics. Here, a trader interaction model based upon informational cascades in the presence of information thresholds is used to construct a new model of asset price returns that allows for both quiescent and herd-like regimes. Agent interaction is modelled using a stochastic pulse-coupled network, parametrised by information thresholds and a network coupling probability. Agents may possess either one or two information thresholds that, in each case, determine the number of distinct states an agent may occupy before trading takes place. In the case where agents possess two thresholds (labelled as the finite state-space model, corresponding to agents' accumulating information over a bounded state-space), and where coupling strength is maximal, an asymptotic expression for the cascade-size probability is derived and shown to follow a power law when a critical value of network coupling probability is attained. For a range of model parameters, a mixture of negative binomial distributions is used to approximate the cascade-size distribution. This approximation is subsequently used to express the volatility of model price returns in terms of the model parameter which controls the network coupling probability. In the case where agents possess a single pulse-coupling threshold (labelled as the semi-infinite state-space model corresponding to agents' accumulating information over an unbounded state-space), numerical evidence is presented that demonstrates volatility clustering and long-memory patterns in the volatility of asset returns. Finally, output from the model is compared to both the distribution of historical stock returns and the market

  11. Preschoolers’ Physical Activity Behaviours

    PubMed Central

    Irwin, Jennifer D.; He, Meizi; Bouck, L. Michelle Sangster; Tucker, Patricia; Pollett, Graham L.

    2016-01-01

    Objectives To understand parents’ perspectives of their preschoolers’ physical activity behaviours. Methods A maximum variation sample of 71 parents explored their preschoolers’ physical activity behaviours through 10 semi-structured focus group discussions. Results Parents perceived Canada’s Physical Activity Guidelines for Children as inadequate; that their preschoolers get and need more than 30–90 minutes of activity daily; and that physical activity habits must be established during the preschool years. Nine barriers against and facilitators toward adequate physical activity were proposed: child’s age, weather, daycare, siblings, finances, time, society and safety, parents’ impact, and child’s activity preferences. Discussion The need for education and interventions that address current barriers are essential for establishing physical activity as a lifestyle behaviour during early childhood and, consequently, helping to prevent both childhood and adulthood obesity. PMID:16625802

  12. Lifestyle behaviours during pregnancy.

    PubMed

    Clissold, T L; Hopkins, W G; Seddon, R J

    1991-03-27

    Lifestyle behaviours of 183 women before and during pregnancy were investigated by retrospective questionnaire in the first few days postpartum. The threshold of cigarette smoking for a reduction in birth weight was exceeded at full term by 17% of the women, but only 1% exceeded a similar threshold for alcohol consumption. Consumption below the recommended minimum level for one or more major food groups was reported by 35% of the women during pregnancy. Only 36% of the women were vigorously active before pregnancy, and only 13% remained so throughout pregnancy. Level of education was a significant predictor of healthy lifestyle behaviours. Concern for their baby's and their own health were the main reasons given for change in behaviour during pregnancy, while doctor's advice and antenatal classes were cited infrequently. A new approach to lifestyle enhancement by health professionals might promote desirable changes in relation to smoking and possibly also food consumption and physical activity.

  13. FLEXIBLE COUPLING

    DOEpatents

    Babelay, E.F.

    1962-02-13

    A flexible shaft coupling for operation at speeds in excess of 14,000 rpm is designed which requires no lubrication. A driving sleeve member and a driven sleeve member are placed in concentric spaced relationship. A torque force is transmitted to the driven member from the driving member through a plurality of nylon balls symmetrically disposed between the spaced sleeves. The balls extend into races and recesses within the respective sleeve members. The sleeve members have a suitable clearance therebetween and the balls have a suitable radial clearance during operation of the coupling to provide a relatively loose coupling. These clearances accommodate for both parallel and/or angular misalignments and avoid metal-tometal contact between the sleeve members during operation. Thus, no lubrication is needed, and a minimum of vibrations is transmitted between the sleeve members. (AEC)

  14. Prosthesis coupling

    NASA Technical Reports Server (NTRS)

    Reswick, J. B.; Mooney, V.; Bright, C. W.; Owens, L. J. (Inventor)

    1979-01-01

    A coupling for use in an apparatus for connecting a prosthesis to the bone of a stump of an amputated limb is described which permits a bio-compatible carbon sleeve forming a part of the prosthesis connector to float so as to prevent disturbing the skin seal around the carbon sleeve. The coupling includes a flexible member interposed between a socket that is inserted within an intermedullary cavity of the bone and the sleeve. A lock pin is carried by the prosthesis and has a stem portion which is adapted to be coaxially disposed and slideably within the tubular female socket for securing the prosthesis to the stump. The skin around the percutaneous carbon sleeve is able to move as a result of the flexing coupling so as to reduce stresses caused by changes in the stump shape and/or movement between the bone and the flesh portion of the stump.

  15. Cephalopod consciousness: behavioural evidence.

    PubMed

    Mather, Jennifer A

    2008-03-01

    Behavioural evidence suggests that cephalopod molluscs may have a form of primary consciousness. First, the linkage of brain to behaviour seen in lateralization, sleep and through a developmental context is similar to that of mammals and birds. Second, cephalopods, especially octopuses, are heavily dependent on learning in response to both visual and tactile cues, and may have domain generality and form simple concepts. Third, these animals are aware of their position, both within themselves and in larger space, including having a working memory of foraging areas in the recent past. Thus if using a 'global workspace' which evaluates memory input and focuses attention is the criterion, cephalopods appear to have primary consciousness.

  16. Neurodevelopmental and behavioural paediatrics.

    PubMed

    McDowell, Michael

    2015-01-01

    One of the notable shifts in Paediatrics across the last 50 years has been towards disorders that are chronic and qualitative in nature. In addition to physical health, these impact on childhood development, behaviour and wellbeing. Understanding and management of these problems extends the traditional biological toolkit of paediatrics into the complexities of uncertainties of psychological and social context. In Australasia, the profession has responded with the development of Community Paediatrics as a recognised sub-specialty, of which Neurodevelopmental and Behavioural Paediatrics is an important component. These developments are reviewed along with consideration of future challenges for this field of health care.

  17. Challenging Student Behaviour

    ERIC Educational Resources Information Center

    Jones, Glyn; Philp, Clare

    2011-01-01

    The issue of poor student behaviour within higher education institutions (HEIs) has been well documented in recent years. Although the number of reported cases constitutes a very small percentage of the overall student population in the UK, the impact of student misconduct on the rest of the student body and staff in HEIs can be substantial. For…

  18. Locomotion and postural behaviour

    NASA Astrophysics Data System (ADS)

    Schmidt, M.

    2010-05-01

    The purpose of this article is to provide a survey of the diversity of primate locomotor behaviour for people who are involved in research using laboratory primates. The main locomotor modes displayed by primates are introduced with reference to some general morphological adaptations. The relationships between locomotor behaviour and body size, habitat structure and behavioural context will be illustrated because these factors are important determinants of the evolutionary diversity of primate locomotor activities. They also induce the high individual plasticity of the locomotor behaviour for which primates are well known. The article also provides a short overview of the preferred locomotor activities in the various primate families. A more detailed description of locomotor preferences for some of the most common laboratory primates is included which also contains information about substrate preferences and daily locomotor activities which might useful for laboratory practice. Finally, practical implications for primate husbandry and cage design are provided emphasizing the positive impact of physical activity on health and psychological well-being of primates in captivity.

  19. Urban behavioural adaptation.

    PubMed

    Garroway, Colin J; Sheldon, Ben C

    2013-07-01

    A large and growing proportion of the world is impacted directly by human activities; among the most extreme of these is the spread of urban environments. Environmental change associated with urbanization represents a potentially potent source of selection. While urban environments generally have lowered biodiversity, some clades seem to thrive in urban settings. For example, many members of the bird family Turdidae, known as the ‘truethrushes’ and the blackbird Turdus merula (Fig. 1) in particular, are familiar urban species. Indeed, the colonization of urban environments by blackbirds has become a textbook case study for our understanding of the many ways a wild species can deal with urbanization. In this issue, Mueller et al. (Molecular Ecology, 00, 2013, 00) add to that story by beginning to address the genetic nature of behavioural adaptation of blackbirds colonizing urban areas. They do this by testing for divergence between paired urban and rural samples at a suite of candidate genes with hypothesized effects on behaviours thought to be important for the colonization of urban environments.They find evidence for consistent patterns of divergence at an exonic microsatellite associated with the SERT gene. SERT has a number of hypothesized behavioural effects, including harm avoidance, which may be associated with tolerating the hustle and bustle of urban environments. This is among the first evidence that behavioural differences between urban and rural environments have a genetic basis and this work suggests that urban environments can in some cases exert homogeneous selection pressures. PMID:23967452

  20. Changing client behaviour.

    PubMed

    Clark, Kathryn

    2013-12-14

    Persuading someone to change their behaviour, whether for their own benefit or for that of their pet, is not an easy task. A session at this year's BVA Congress considered strategies to encourage people to 'change the norm'. Kathryn Clark reports.

  1. Restoration of rhythmicity in diffusively coupled dynamical networks

    PubMed Central

    Zou, Wei; Senthilkumar, D. V.; Nagao, Raphael; Kiss, István Z.; Tang, Yang; Koseska, Aneta; Duan, Jinqiao; Kurths, Jürgen

    2015-01-01

    Oscillatory behaviour is essential for proper functioning of various physical and biological processes. However, diffusive coupling is capable of suppressing intrinsic oscillations due to the manifestation of the phenomena of amplitude and oscillation deaths. Here we present a scheme to revoke these quenching states in diffusively coupled dynamical networks, and demonstrate the approach in experiments with an oscillatory chemical reaction. By introducing a simple feedback factor in the diffusive coupling, we show that the stable (in)homogeneous steady states can be effectively destabilized to restore dynamic behaviours of coupled systems. Even a feeble deviation from the normal diffusive coupling drastically shrinks the death regions in the parameter space. The generality of our method is corroborated in diverse non-linear systems of diffusively coupled paradigmatic models with various death scenarios. Our study provides a general framework to strengthen the robustness of dynamic activity in diffusively coupled dynamical networks. PMID:26173555

  2. Restoration of rhythmicity in diffusively coupled dynamical networks.

    PubMed

    Zou, Wei; Senthilkumar, D V; Nagao, Raphael; Kiss, István Z; Tang, Yang; Koseska, Aneta; Duan, Jinqiao; Kurths, Jürgen

    2015-01-01

    Oscillatory behaviour is essential for proper functioning of various physical and biological processes. However, diffusive coupling is capable of suppressing intrinsic oscillations due to the manifestation of the phenomena of amplitude and oscillation deaths. Here we present a scheme to revoke these quenching states in diffusively coupled dynamical networks, and demonstrate the approach in experiments with an oscillatory chemical reaction. By introducing a simple feedback factor in the diffusive coupling, we show that the stable (in)homogeneous steady states can be effectively destabilized to restore dynamic behaviours of coupled systems. Even a feeble deviation from the normal diffusive coupling drastically shrinks the death regions in the parameter space. The generality of our method is corroborated in diverse non-linear systems of diffusively coupled paradigmatic models with various death scenarios. Our study provides a general framework to strengthen the robustness of dynamic activity in diffusively coupled dynamical networks. PMID:26173555

  3. Restoration of rhythmicity in diffusively coupled dynamical networks

    NASA Astrophysics Data System (ADS)

    Zou, Wei; Senthilkumar, D. V.; Nagao, Raphael; Kiss, István Z.; Tang, Yang; Koseska, Aneta; Duan, Jinqiao; Kurths, Jürgen

    2015-07-01

    Oscillatory behaviour is essential for proper functioning of various physical and biological processes. However, diffusive coupling is capable of suppressing intrinsic oscillations due to the manifestation of the phenomena of amplitude and oscillation deaths. Here we present a scheme to revoke these quenching states in diffusively coupled dynamical networks, and demonstrate the approach in experiments with an oscillatory chemical reaction. By introducing a simple feedback factor in the diffusive coupling, we show that the stable (in)homogeneous steady states can be effectively destabilized to restore dynamic behaviours of coupled systems. Even a feeble deviation from the normal diffusive coupling drastically shrinks the death regions in the parameter space. The generality of our method is corroborated in diverse non-linear systems of diffusively coupled paradigmatic models with various death scenarios. Our study provides a general framework to strengthen the robustness of dynamic activity in diffusively coupled dynamical networks.

  4. Longitudinal Links between Early Coparenting and Infant Behaviour Problems

    ERIC Educational Resources Information Center

    LeRoy, Michelle; Mahoney, Annette; Pargament, Kenneth I.; DeMaris, Alfred

    2013-01-01

    This study of 164 married couples examined longitudinal links between parents' perceptions of coparenting support and undermining by spouse at 6 months postpartum and infant behaviour problems at the age of 12 months after controlling for marital quality, individual parenting, and infant temperament. Multiple methods (i.e. parent reports and…

  5. The evolution of behaviour therapy and cognitive behaviour therapy.

    PubMed

    Rachman, S

    2015-01-01

    The historical background of the development of behaviour therapy is described. It was based on the prevailing behaviourist psychology and constituted a fundamentally different approach to the causes and treatment of psychological disorders. It had a cold reception and the idea of treating the behaviour of neurotic and other patients was regarded as absurd. The opposition of the medical profession and psychoanalysts is explained. Parallel but different forms of behaviour therapy developed in the US and UK. The infusion of cognitive concepts and procedures generated a merger of behaviour therapy and cognitive therapy, cognitive behaviour therapy (CBT). The strengths and limitations of the early and current approaches are evaluated.

  6. Exploratory behaviour and novel predator recognition: behavioural correlations across contexts.

    PubMed

    Blake, C A; Gabor, C R

    2016-08-01

    It was hypothesized that the exploratory behaviour of an individual measured in a novel environment could predict its behaviour in response to a novel predator. This study examined novel predator recognition in the western mosquitofish Gambusia affinis, a species with individual differences in risk-taking, activity and exploration in novel environments. Prey responded with characteristic shoaling and avoidance in response to native predators, but did not show characteristic antipredator behaviour towards novel predators. Furthermore, G. affinis exhibited individual-level behavioural correlations across contexts but only when prey were tested with native predators. This could be the result of native predatory selection on behavioural correlations in the prey species. PMID:27220896

  7. Behaviour and welfare.

    PubMed

    Savory, C J; Hughes, B O

    2010-08-01

    1. We have chosen papers which we feel are representative of important subjects which have been covered by the Journal over a period of 50 years. We would not claim that these are objectively the best papers, for that is a matter of personal judgement, but we consider that they have made significant contributions to knowledge and understanding in poultry behaviour and welfare. 2. John Savory has selected 8 papers from Volumes 1-25 of British Poultry Science (1960-1984), which deal with 5 different aspects of behaviour and welfare: embryonic responses, feather pecking and cannibalism, cage floor preferences, lameness in broilers and myopathy in turkeys. 3. Barry Hughes has selected 11 papers from Volumes 26-50 (1985-2009) of British Poultry Science. Four topics been chosen: broken bones in layers, furnished cages, interaction of birds with machines, and stocking density and bird space.

  8. Predicting People's Environmental Behaviour: Theory of Planned Behaviour and Model of Responsible Environmental Behaviour

    ERIC Educational Resources Information Center

    Chao, Yu-Long

    2012-01-01

    Using different measures of self-reported and other-reported environmental behaviour (EB), two important theoretical models explaining EB--Hines, Hungerford and Tomera's model of responsible environmental behaviour (REB) and Ajzen's theory of planned behaviour (TPB)--were compared regarding the fit between model and data, predictive ability,…

  9. Nano-chemo-mechanical signature of conventional oil-well cement systems: Effects of elevated temperature and curing time

    SciTech Connect

    Krakowiak, Konrad J.; Thomas, Jeffrey J.; Musso, Simone; James, Simon; Akono, Ange-Therese; Ulm, Franz-Josef

    2015-01-15

    With ever more challenging (T,p) environments for cementing applications in oil and gas wells, there is a need to identify the fundamental mechanisms of fracture resistant oil well cements. We report results from a multi-technique investigation of behavior and properties of API class G cement and silica-enriched cement systems subjected to hydrothermal curing from 30 °C to 200 °C; including electron probe microanalysis, X-ray diffraction, thermogravimetry analysis, electron microscopy, neutron scattering (SANS), and fracture scratch testing. The results provide a new insight into the link between system chemistry, micro-texture and micro-fracture toughness. We suggest that the strong correlation found between chemically modulated specific surface and fracture resistance can explain the drop in fracture properties of neat oil-well cements at elevated temperatures; the fracture property enhancement in silica-rich cement systems, between 110° and 175 °C; and the drop in fracture properties of such systems through prolonged curing over 1 year at 200 °C.

  10. Effects of chemo-mechanical polishing on CdZnTe X-ray and gamma-ray detectors

    SciTech Connect

    Egarievwe, Stephen E.; Hossain, Anwar; Okwechime, Ifechukwude O.; Gul, Rubi; James, Ralph B.

    2015-06-23

    Here, mechanically polishing cadmium zinc telluride (CdZnTe) wafers for x-ray and gamma-ray detectors often is inadequate in removing surface defects caused by cutting them from the ingots. Fabrication-induced defects, such as surface roughness, dangling bonds, and nonstoichiometric surfaces, often are reduced through polishing and etching the surface. In our earlier studies of mechanical polishing with alumina powder, etching with hydrogen bromide in hydrogen peroxide solution, and chemomechanical polishing with bromine–methanol–ethylene glycol solution, we found that the chemomechanical polishing process produced the least surface leakage current. In this research, we focused on using two chemicals to chemomechanically polish CdZnTe wafers after mechanical polishing, viz. bromine–methanol–ethylene glycol (BME) solution, and hydrogen bromide (HBr) in a hydrogen peroxide and ethylene–glycol solution. We used x-ray photoelectron spectroscopy (XPS), current–voltage (I–V) measurements, and Am-241 spectral response measurements to characterize and compare the effects of each solution. The results show that the HBr-based solution produced lower leakage current than the BME solution. Results from using the same chemomechanical polishing solution on two samples confirmed that the surface treatment affects the measured bulk current (a combination of bulk and surface currents). XPS results indicate that the tellurium oxide to tellurium peak ratios for the mechanical polishing process were reduced significantly by chemomechanical polishing using the BME solution (78.9% for Te 3d5/2O2 and 76.7% for Te 3d3/2O2) compared with the HBr-based solution (27.6% for Te 3d5/2O2 and 35.8% for Te 3d3/2O2). Spectral response measurements showed that the 59.5-keV peak of Am-241 remained under the same channel number for all three CdZnTe samples. While the BME-based solution gave a better performance of 7.15% full-width at half-maximum (FWHM) compared with 7.59% FWHM for the HBr-based solution, the latter showed a smaller variation in performance of 0.39% FWHM over 7 days compared with 0.69% for the BME-based solution.

  11. Effects of chemo-mechanical polishing on CdZnTe X-ray and gamma-ray detectors

    DOE PAGESBeta

    Egarievwe, Stephen E.; Hossain, Anwar; Okwechime, Ifechukwude O.; Gul, Rubi; James, Ralph B.

    2015-06-23

    Here, mechanically polishing cadmium zinc telluride (CdZnTe) wafers for x-ray and gamma-ray detectors often is inadequate in removing surface defects caused by cutting them from the ingots. Fabrication-induced defects, such as surface roughness, dangling bonds, and nonstoichiometric surfaces, often are reduced through polishing and etching the surface. In our earlier studies of mechanical polishing with alumina powder, etching with hydrogen bromide in hydrogen peroxide solution, and chemomechanical polishing with bromine–methanol–ethylene glycol solution, we found that the chemomechanical polishing process produced the least surface leakage current. In this research, we focused on using two chemicals to chemomechanically polish CdZnTe wafers aftermore » mechanical polishing, viz. bromine–methanol–ethylene glycol (BME) solution, and hydrogen bromide (HBr) in a hydrogen peroxide and ethylene–glycol solution. We used x-ray photoelectron spectroscopy (XPS), current–voltage (I–V) measurements, and Am-241 spectral response measurements to characterize and compare the effects of each solution. The results show that the HBr-based solution produced lower leakage current than the BME solution. Results from using the same chemomechanical polishing solution on two samples confirmed that the surface treatment affects the measured bulk current (a combination of bulk and surface currents). XPS results indicate that the tellurium oxide to tellurium peak ratios for the mechanical polishing process were reduced significantly by chemomechanical polishing using the BME solution (78.9% for Te 3d5/2O2 and 76.7% for Te 3d3/2O2) compared with the HBr-based solution (27.6% for Te 3d5/2O2 and 35.8% for Te 3d3/2O2). Spectral response measurements showed that the 59.5-keV peak of Am-241 remained under the same channel number for all three CdZnTe samples. While the BME-based solution gave a better performance of 7.15% full-width at half-maximum (FWHM) compared with 7.59% FWHM for the HBr-based solution, the latter showed a smaller variation in performance of 0.39% FWHM over 7 days compared with 0.69% for the BME-based solution.« less

  12. An autonomous drug release system based on chemo-mechanical energy conversion "Organic Engine" for feedback control of blood glucose.

    PubMed

    Kato, Ryodai; Munkhjargal, Munkhbayar; Takahashi, Daishi; Arakawa, Takahiro; Kudo, Hiroyuki; Mitsubayashi, Kohji

    2010-12-15

    A novel autonomous drug release system was fabricated and tested. The system consists of two integrated units: decompression unit and drug release unit. The decompression unit was fabricated by separating a cylindrical cell into a top cell (gas phase) and a bottom cell (liquid phase) by glucose oxidase (GOD) enzyme immobilized membrane. The enzyme membrane recognizes glucose and converts chemical energy found in glucose to mechanical energy. The linear correlation between glucose concentration and de-pressure slope of the top cell was revealed as applying glucose solution to the bottom cell. Afterward, the drug release unit which utilizes the energy of the decompression unit as a power source was fabricated and evaluated by recording its release actions. The drug release unit was made to release at a constant quantity of drug in the liquid phase. The system was then fabricated by combining the decompression unit and the drug release unit. And it was evaluated in an open loop and in a closed loop by applying a mixture of glucose solution (100 mmol/l) and NADH(+) using glucose dehydrogenase enzyme (GDH) as a glucose reducer. Glucose concentration decreased gradually in the closed loop and, as a consequence, interval time of the GDH release became longer. In other words, an inverse correlation between actuation interval of the system and glucose concentration was shown. As a result, the possibility of feedback control of glucose concentration by the drug release system without external energy was confirmed.

  13. Critical behaviour of the local magnetic susceptibility in a ferromagnetic film

    NASA Astrophysics Data System (ADS)

    Korneta, W.; Pytel, Z.

    1985-07-01

    The nearest-neighbour Ising model of a ferromagnetic film in which couplings between surface spins may differ from couplings between remaining spins is considered. Using the mean-field approximation, the local magnetic susceptibility defined as the derivative of the local magnetization with respect to the external uniform magnetic field is obtained. The behaviour of the local magnetic susceptibility near the ordinary, surface-bulk and surface phase transitions and in a range of temperatures where physical quantities have pseudocritical behaviour is discussed. The critical behaviour of the local magnetic susceptibility in a three-dimensional semi-infinite model is also given for comparison.

  14. Dark coupling

    SciTech Connect

    Gavela, M.B.; Hernández, D.; Honorez, L. Lopez; Mena, O.; Rigolin, S. E-mail: d.hernandez@uam.es E-mail: omena@ific.uv.es

    2009-07-01

    The two dark sectors of the universe—dark matter and dark energy—may interact with each other. Background and linear density perturbation evolution equations are developed for a generic coupling. We then establish the general conditions necessary to obtain models free from non-adiabatic instabilities. As an application, we consider a viable universe in which the interaction strength is proportional to the dark energy density. The scenario does not exhibit ''phantom crossing'' and is free from instabilities, including early ones. A sizeable interaction strength is compatible with combined WMAP, HST, SN, LSS and H(z) data. Neutrino mass and/or cosmic curvature are allowed to be larger than in non-interacting models. Our analysis sheds light as well on unstable scenarios previously proposed.

  15. Thermoacoustic couple

    DOEpatents

    Wheatley, J.C.; Swift, G.W.; Migliori, A.

    1983-10-04

    An apparatus and method for determining acoustic power density level and its direction in a fluid using a single sensor are disclosed. The preferred embodiment of the apparatus, which is termed a thermoacoustic couple, consists of a stack of thin, spaced apart polymeric plates, selected ones of which include multiple bimetallic thermocouple junctions positioned along opposite end edges thereof. The thermocouple junctions are connected in series in the nature of a thermopile, and are arranged so as to be responsive to small temperature differences between the opposite edges of the plates. The magnitude of the temperature difference, as represented by the magnitude of the electrical potential difference generated by the thermopile, is found to be directly related to the level of acoustic power density in the gas.

  16. Evolving cognitive-behavioural dependencies in situated agents for behavioural robustness.

    PubMed

    Fernandez-Leon, Jose A

    2011-11-01

    This article investigates the emergence of robust behaviour in agents with dynamically limited controllers (monostable agents), and compares their performance to less limited ones (bistable agents). 'Dynamically limited' here refers to a reduced quantity of steady states that an agent controller exhibits when it does not receive stimulus from the environment. Agents are evolved for categorical perception, a minimal cognitive task, and must correlate approaching or avoiding movements based on (two) different types of objects. Results indicate a significant tendency to better behavioural robustness by monostable in contrast to bistable agents in the presence of sensorimotor, mutational, and structural perturbations. Discussions here focus on a further dependence to coupled dynamics by the former agents to explain such a tendency.

  17. REM sleep Behaviour Disorder.

    PubMed

    Ferini-Strambi, Luigi; Rinaldi, Fabrizio; Giora, Enrico; Marelli, Sara; Galbiati, Andrea

    2016-01-01

    Rapid Eye Movement (REM) sleep Behaviour Disorder (RBD) is a REM sleep parasomnia characterized by loss of the muscle atonia that typically occurs during REM sleep, therefore allowing patients to act out their dreams. RBD manifests itself clinically as a violent behaviour occurring during the night, and is detected at the polysomnography by phasic and/or tonic muscle activity on the electromyography channel. In absence of neurological signs or central nervous system lesions, RBD is defined as idiopathic. Nevertheless, in a large number of cases the development of neurodegenerative diseases in RBD patients has been described, with the duration of the follow-up representing a fundamental aspect. A growing number of clinical, neurophysiologic and neuropsychological studies aimed to detect early markers of neurodegenerative dysfunction in RBD patients. Anyway, the evidence of impaired cortical activity, subtle neurocognitive dysfunction, olfactory and autonomic impairment and neuroimaging brain changes in RBD patients is challenging the concept of an idiopathic form of RBD, supporting the idea of RBD as an early manifestation of a more complex neurodegenerative process. PMID:26427638

  18. Driver behaviour at roadworks.

    PubMed

    Walker, Guy; Calvert, Malcolm

    2015-11-01

    There is an incompatibility between how transport engineers think drivers behave in roadworks and how they actually behave. As a result of this incompatibility we are losing approximately a lane's worth of capacity in addition to those closed by the roadworks themselves. The problem would have little significance were it not for the fact a lane of motorway costs approx. £30 m per mile to construct and £43 k a year to maintain, and that many more roadworks are planned as infrastructure constructed 40 or 50 years previously reaches a critical stage in its lifecycle. Given current traffic volumes, and the sensitivity of road networks to congestion, the effects of roadworks need to be accurately assessed. To do this requires a new ergonomic approach. A large-scale observational study of real traffic conditions was used to identify the issues and impacts, which were then mapped to the ergonomic knowledge-base on driver behaviour, and combined to developed practical guidelines to help in modelling future roadworks scenarios with greater behavioural accuracy. Also stemming from the work are novel directions for the future ergonomic design of roadworks themselves.

  19. Driver behaviour at roadworks.

    PubMed

    Walker, Guy; Calvert, Malcolm

    2015-11-01

    There is an incompatibility between how transport engineers think drivers behave in roadworks and how they actually behave. As a result of this incompatibility we are losing approximately a lane's worth of capacity in addition to those closed by the roadworks themselves. The problem would have little significance were it not for the fact a lane of motorway costs approx. £30 m per mile to construct and £43 k a year to maintain, and that many more roadworks are planned as infrastructure constructed 40 or 50 years previously reaches a critical stage in its lifecycle. Given current traffic volumes, and the sensitivity of road networks to congestion, the effects of roadworks need to be accurately assessed. To do this requires a new ergonomic approach. A large-scale observational study of real traffic conditions was used to identify the issues and impacts, which were then mapped to the ergonomic knowledge-base on driver behaviour, and combined to developed practical guidelines to help in modelling future roadworks scenarios with greater behavioural accuracy. Also stemming from the work are novel directions for the future ergonomic design of roadworks themselves. PMID:26154200

  20. REM sleep Behaviour Disorder.

    PubMed

    Ferini-Strambi, Luigi; Rinaldi, Fabrizio; Giora, Enrico; Marelli, Sara; Galbiati, Andrea

    2016-01-01

    Rapid Eye Movement (REM) sleep Behaviour Disorder (RBD) is a REM sleep parasomnia characterized by loss of the muscle atonia that typically occurs during REM sleep, therefore allowing patients to act out their dreams. RBD manifests itself clinically as a violent behaviour occurring during the night, and is detected at the polysomnography by phasic and/or tonic muscle activity on the electromyography channel. In absence of neurological signs or central nervous system lesions, RBD is defined as idiopathic. Nevertheless, in a large number of cases the development of neurodegenerative diseases in RBD patients has been described, with the duration of the follow-up representing a fundamental aspect. A growing number of clinical, neurophysiologic and neuropsychological studies aimed to detect early markers of neurodegenerative dysfunction in RBD patients. Anyway, the evidence of impaired cortical activity, subtle neurocognitive dysfunction, olfactory and autonomic impairment and neuroimaging brain changes in RBD patients is challenging the concept of an idiopathic form of RBD, supporting the idea of RBD as an early manifestation of a more complex neurodegenerative process.

  1. Resonant neurons and bushcricket behaviour.

    PubMed

    Webb, Barbara; Wessnitzer, Jan; Bush, Sarah; Schul, Johannes; Buchli, Jonas; Ijspeert, Auke

    2007-02-01

    The resonant properties of the intrinsic dynamics of single neurons could play a direct role in behaviour. One plausible role is in the recognition of temporal patterns, such as that seen in the auditory communication systems of Orthoptera. Recent behavioural data from bushcrickets suggests that this behaviour has interesting resonance properties, but the underlying mechanism is unknown. Here we show that a very simple and general model for neural resonance could directly account for the different behavioural responses of bushcrickets to different song patterns.

  2. Retrofitting gear couplings with diaphragm couplings

    SciTech Connect

    Mancuso, J.R. )

    1988-10-01

    Retrofitting a coupling should not be an afterthought when upgrading a system. Couplings are an integral part of a drive train and should be a major consideration. This article discusses guidelines that should be used when replacing gear couplings with diaphragm couplings. Reviewed are the coupling selection process: how and to what extent the desired diaphragm couplings should be matched to the gear coupling. Also discussed are the details of coupling modification that can be made to accommodate system performance. Included are how changes in materials, configuration and design can help tune a diaphragm coupling to meet the characteristics of the previous gear couplings. The article also discusses the retrofit process for a specific syngas train at International Minerals and Chemical Corp., Sterlington, La.

  3. Neural coding in a single sensory neuron controlling opposite seeking behaviours in Caenorhabditis elegans

    PubMed Central

    Kuhara, Atsushi; Ohnishi, Noriyuki; Shimowada, Tomoyasu; Mori, Ikue

    2011-01-01

    Unveiling the neural codes for intricate behaviours is a major challenge in neuroscience. The neural circuit for the temperature-seeking behaviour of Caenorhabditis elegans is an ideal system to dissect how neurons encode sensory information for the execution of behavioural output. Here we show that the temperature-sensing neuron AFD transmits both stimulatory and inhibitory neural signals to a single interneuron AIY. In this circuit, a calcium concentration threshold in AFD acts as a switch for opposing neural signals that direct the opposite behaviours. Remote control of AFD activity, using a light-driven ion pump and channel, reveals that diverse reduction levels of AFD activity can generate warm- or cold-seeking behaviour. Calcium imaging shows that AFD uses either stimulatory or inhibitory neuronal signalling onto AIY, depending on the calcium concentration threshold in AFD. Thus, dual neural regulation in opposite directions is directly coupled to behavioural inversion in the simple neural circuit. PMID:21673676

  4. Phenotypic variability in unicellular organisms: from calcium signalling to social behaviour.

    PubMed

    Vogel, David; Nicolis, Stamatios C; Perez-Escudero, Alfonso; Nanjundiah, Vidyanand; Sumpter, David J T; Dussutour, Audrey

    2015-11-22

    Historically, research has focused on the mean and often neglected the variance. However, variability in nature is observable at all scales: among cells within an individual, among individuals within a population and among populations within a species. A fundamental quest in biology now is to find the mechanisms that underlie variability. Here, we investigated behavioural variability in a unique unicellular organism, Physarum polycephalum. We combined experiments and models to show that variability in cell signalling contributes to major differences in behaviour underpinning some aspects of social interactions. First, following thousands of cells under various contexts, we identified distinct behavioural phenotypes: 'slow-regular-social', 'fast-regular-social' and 'fast-irregular-asocial'. Second, coupling chemical analysis and behavioural assays we found that calcium signalling is responsible for these behavioural phenotypes. Finally, we show that differences in signalling and behaviour led to alternative social strategies. Our results have considerable implications for our understanding of the emergence of variability in living organisms. PMID:26609088

  5. Phenotypic variability in unicellular organisms: from calcium signalling to social behaviour.

    PubMed

    Vogel, David; Nicolis, Stamatios C; Perez-Escudero, Alfonso; Nanjundiah, Vidyanand; Sumpter, David J T; Dussutour, Audrey

    2015-11-22

    Historically, research has focused on the mean and often neglected the variance. However, variability in nature is observable at all scales: among cells within an individual, among individuals within a population and among populations within a species. A fundamental quest in biology now is to find the mechanisms that underlie variability. Here, we investigated behavioural variability in a unique unicellular organism, Physarum polycephalum. We combined experiments and models to show that variability in cell signalling contributes to major differences in behaviour underpinning some aspects of social interactions. First, following thousands of cells under various contexts, we identified distinct behavioural phenotypes: 'slow-regular-social', 'fast-regular-social' and 'fast-irregular-asocial'. Second, coupling chemical analysis and behavioural assays we found that calcium signalling is responsible for these behavioural phenotypes. Finally, we show that differences in signalling and behaviour led to alternative social strategies. Our results have considerable implications for our understanding of the emergence of variability in living organisms.

  6. Combining animal movements and behavioural data to detect behavioural states.

    PubMed

    Nams, Vilis O

    2014-10-01

    Animal movement paths show variation in space caused by qualitative shifts in behaviours. I present a method that (1) uses both movement path data and ancillary sensor data to detect natural breakpoints in animal behaviour and (2) groups these segments into different behavioural states. The method can also combine analyses of different path segments or paths from different individuals. It does not assume any underlying movement mechanism. I give an example with simulated data. I also show the effects of random variation, # of states and # of segments on this method. I present a case study of a fisher movement path spanning 8 days, which shows four distinct behavioural states divided into 28 path segments when only turning angles and speed were considered. When accelerometer data were added, the analysis shows seven distinct behavioural states divided into 41 path segments. PMID:25040789

  7. Behavioural and Cognitive-Behavioural Treatments of Parasomnias

    PubMed Central

    Galbiati, Andrea; Rinaldi, Fabrizio; Giora, Enrico; Ferini-Strambi, Luigi; Marelli, Sara

    2015-01-01

    Parasomnias are unpleasant or undesirable behaviours or experiences that occur predominantly during or within close proximity to sleep. Pharmacological treatments of parasomnias are available, but their efficacy is established only for few disorders. Furthermore, most of these disorders tend spontaneously to remit with development. Nonpharmacological treatments therefore represent valid therapeutic choices. This paper reviews behavioural and cognitive-behavioural managements employed for parasomnias. Referring to the ICSD-3 nosology we consider, respectively, NREM parasomnias, REM parasomnias, and other parasomnias. Although the efficacy of some of these treatments is proved, in other cases their clinical evidence cannot be provided because of the small size of the samples. Due to the rarity of some parasomnias, further multicentric researches are needed in order to offer a more complete account of behavioural and cognitive-behavioural treatments efficacy. PMID:26101458

  8. The mechanics of active clays circulated by salts, acids and bases

    NASA Astrophysics Data System (ADS)

    Gajo, Alessandro; Loret, Benjamin

    2007-08-01

    A model that accounts for electro-chemo-mechanical couplings in clays, due to the presence of dissolved salts and acids and bases, is developed and applied to simulate experimental data. Chemically sensitive clays are viewed as two-phase multi-species saturated porous media circulated by an electrolyte. To the authors' best knowledge, no other comprehensive project to embody the effects of pH in the elastic-plastic behavior of geomaterials has been attempted so far. The developments are embedded in the framework of the thermodynamics of multi-phase multi-species porous media. This approach serves to structure the model, and to motivate constitutive equations. The present extension capitalizes upon the earlier developments by Gajo et al. [2002. Electro-chemo-mechanical couplings in saturated porous media: elastic-plastic behaviour of heteroionic expansive clays. Int. J. Solids Struct. 39, 4327-4362] and Gajo and Loret [2004. Transient analysis of ionic replacement in elastic-plastic expansive clays. Int. J. Solids Struct. 41(26), 7493-7531], which were devoted to modeling chemo-mechanical couplings at constant pH. Four transfer mechanisms between the solid and fluid phases are delineated in the model: (1) hydration, (2) ion exchange, (3) acidification, (4) alkalinization. Thus all fundamental exchanges at particle level are fully taken into account. Only mineral dissolution is neglected, since experimental observations indicate a negligible role of mineral dissolution for active clays at room temperature. In particular, the newly considered mechanisms of acidification and alkalinization directly affect the electrical charge of clay particles and thus have a key role in the electro-chemo-mechanical couplings. These four mechanisms are seen as controlling both elastic and elasto-plastic behaviors. Depending on concentrations and ionic affinities to the clay mineral, the transfer mechanisms either compete or cooperate to modify the compressibility and strength of the

  9. Clustering and phase synchronization in populations of coupled phase oscillators

    NASA Astrophysics Data System (ADS)

    Cascallares, Guadalupe; Gleiser, Pablo M.

    2015-10-01

    In many species daily rhythms are endogenously generated by groups of coupled neurons that play the role of a circadian pacemaker. The adaptation of the circadian clock to environmental and seasonal changes has been proposed to be regulated by a dual oscillator system. In order to gain insight into this model, we analyzed the synchronization properties of two fully coupled groups of Kuramoto oscillators. Each group has an internal coupling parameter and the interaction between the two groups can be controlled by two parameters allowing for symmetric or non-symmetric coupling. We show that even for such a simple model counterintuitive behaviours take place, such as a global decrease in synchrony when the coupling between the groups is increased. Through a detailed analysis of the local synchronization processes we explain this behaviour.

  10. The role of son preference in reproductive behaviour in Pakistan.

    PubMed Central

    Hussain, R.; Fikree, F. F.; Berendes, H. W.

    2000-01-01

    The sex of surviving children is an important determinant of reproductive behaviour in South Asia in general and Pakistan in particular. This cohort study evaluates the role of the sex of children on reproductive intentions and subsequent behaviour of women in urban slums of Karachi, Pakistan. The analysis is based on two rounds of surveys conducted in 1990-91 and 1995 of a cohort of married women aged 15-49 years. The results show that pregnancies became increasingly unwanted as the number of surviving sons increased. The sex of surviving children was strongly correlated with subsequent fertility and contraceptive behaviour. However, rather than an exclusive son preference, couples strove for one or more sons and at least one surviving daughter. The policy implications of the link between overt son preference and low status of women are discussed. PMID:10812738

  11. The association between bullying behaviour, arousal levels and behaviour problems.

    PubMed

    Woods, Sarah; White, Eleanor

    2005-06-01

    Research into bullying behaviour has identified two main categories of bullying behaviour, direct bullying and relational bullying, within which different profiles are evident, namely 'pure' bullies, 'pure' victims, bully/victims and neutral children. The current study examined the relationship between direct and relational bullying profiles, arousal levels, and behaviour problems. 242 (males: 121, females: 121) Secondary school pupils (mean age 13.5 years) completed three questionnaires; the Arousal Predisposition Scale (APS) (Behav. Res. Therapy 26 (1988) 415); the School Relationships Questionnaire (SRQ) (detailed in J. Child Psychol. Psychiatry 41(8) (2000) 989; Br. J. Psychol. 92 (2001) 673); the Strengths and Difficulties Questionnaire (SDQ) (J. Child Psychol. Psychiatry 38(5) (1997) 581). Results revealed that the bully/victim profile for direct and relational bullying had the highest levels of arousal compared to other bullying profiles. Conversely, direct 'pure' bullies had low levels of arousal. Clinical behaviour problems as measured by the SDQ were associated with high levels of arousal. Clinically low arousal was not related to either bullying profiles, or behaviour problems. These findings were largely consistent with the arousal theory of behaviour (Crime and personality, 1964), which indicates that arousal levels are differentially associated with distinct behaviour patterns. The results provide implications for bullying intervention strategies, and methods to manage the school environment in relation to arousal levels.

  12. Evolving experience-dependent robust behaviour in embodied agents.

    PubMed

    Fernandez-Leon, Jose A

    2011-01-01

    In this work, based on behavioural and dynamical evidence, a study of simulated agents with the capacity to change feedback from their bodies to accomplish a one-legged walking task is proposed to understand the emergence of coupled dynamics for robust behaviour. Agents evolve with evolutionary-defined biases that modify incoming body signals (sensory offsets). Analyses on whether these agents show further dependence to their environmental coupled dynamics than others with no feedback control is described in this article. The ability to sustain behaviours is tested during lifetime experiments with mutational and sensory perturbations after evolution. Using dynamical systems analysis, this work identifies conditions for the emergence of dynamical mechanisms that remain functional despite sensory perturbations. Results indicate that evolved agents with evolvable sensory offset depends not only on where in neural space the state of the neural system operates, but also on the transients to which the inner-system was being driven by sensory signals from its interactions with the environment, controller, and agent body. Experimental evidence here leads discussions on a dynamical systems perspective on behavioural robustness that goes beyond attractors of controller phase space.

  13. Measuring Thermoforming Behaviour

    NASA Astrophysics Data System (ADS)

    Michaeli, W.; Hopmann, C.; Ederleh, L.; Begemann, M.

    2011-05-01

    Thermoforming is the process of choice for manufacturing thin-gauge or large-area parts for packaging or technical applications. The process allows low-weight parts to be produced rapidly and economically from thermoplastic semi-finished products. A technical and consequently economical problem is the choice of the right material in combination with the thermoformability of the product. The prediction of thermoformability includes the aspired product features and geometry and defined wall thickness distributions, depending on the specific stretchability of the semifinished product. In practice, thermoformability is estimated by empirical tests with the particular semi-finished product using e.g. staged pyramidal moulds or model cars. With this method, it still cannot be ensured that the product can be thermoformed with the intended properties. A promising alternative is the forming simulation using finite element analysis (FEA). For the simulation, it is necessary to describe the material behaviour using defined material models and the appropriate parameters. Therefore, the stress-/strain-behaviour of the semi-finished product under defined conditions is required. There are several, entirely different measurement techniques used in industry and at research facilities. This paper compares a choice of different measurement techniques to provide an objective basis for future work and research. The semi-finished products are examined with the Membrane-Inflation-Rheometer (MIR), an equibiaxial strain rheometer. A flat sample is heated to the desired temperature in silicone oil. During the measurement, a servohydraulic linear drive advances a piston, thus displacing the hot silicone oil and inflating the specimen to form a sphere. Further measurements are carried out with the Karo IV Laboratory Stretching Machine at Brückner Maschinenbau GmbH & Co. KG, Siegsdorf, Germany. The samples are heated using hot air. During the biaxial stretching, the resulting forces at the

  14. Developmental constraints on behavioural flexibility

    PubMed Central

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

    2013-01-01

    We suggest that variation in mammalian behavioural flexibility not accounted for by current socioecological models may be explained in part by developmental constraints. From our own work, we provide examples of constraints affecting variation in behavioural flexibility, not only among individuals, but also among species and higher taxonomic units. We first implicate organizational maternal effects of androgens in shaping individual differences in aggressive behaviour emitted by female spotted hyaenas throughout the lifespan. We then compare carnivores and primates with respect to their locomotor and craniofacial adaptations. We inquire whether antagonistic selection pressures on the skull might impose differential functional constraints on evolvability of skulls and brains in these two orders, thus ultimately affecting behavioural flexibility in each group. We suggest that, even when carnivores and primates would theoretically benefit from the same adaptations with respect to behavioural flexibility, carnivores may nevertheless exhibit less behavioural flexibility than primates because of constraints imposed by past adaptations in the morphology of the limbs and skull. Phylogenetic analysis consistent with this idea suggests greater evolutionary lability in relative brain size within families of primates than carnivores. Thus, consideration of developmental constraints may help elucidate variation in mammalian behavioural flexibility. PMID:23569298

  15. Developmental constraints on behavioural flexibility.

    PubMed

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

    2013-05-19

    We suggest that variation in mammalian behavioural flexibility not accounted for by current socioecological models may be explained in part by developmental constraints. From our own work, we provide examples of constraints affecting variation in behavioural flexibility, not only among individuals, but also among species and higher taxonomic units. We first implicate organizational maternal effects of androgens in shaping individual differences in aggressive behaviour emitted by female spotted hyaenas throughout the lifespan. We then compare carnivores and primates with respect to their locomotor and craniofacial adaptations. We inquire whether antagonistic selection pressures on the skull might impose differential functional constraints on evolvability of skulls and brains in these two orders, thus ultimately affecting behavioural flexibility in each group. We suggest that, even when carnivores and primates would theoretically benefit from the same adaptations with respect to behavioural flexibility, carnivores may nevertheless exhibit less behavioural flexibility than primates because of constraints imposed by past adaptations in the morphology of the limbs and skull. Phylogenetic analysis consistent with this idea suggests greater evolutionary lability in relative brain size within families of primates than carnivores. Thus, consideration of developmental constraints may help elucidate variation in mammalian behavioural flexibility. PMID:23569298

  16. Developmental constraints on behavioural flexibility.

    PubMed

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

    2013-05-19

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

  17. Hormonal mechanisms of cooperative behaviour

    PubMed Central

    Soares, Marta C.; Bshary, Redouan; Fusani, Leonida; Goymann, Wolfgang; Hau, Michaela; Hirschenhauser, Katharina; Oliveira, Rui F.

    2010-01-01

    Research on the diversity, evolution and stability of cooperative behaviour has generated a considerable body of work. As concepts simplify the real world, theoretical solutions are typically also simple. Real behaviour, in contrast, is often much more diverse. Such diversity, which is increasingly acknowledged to help in stabilizing cooperative outcomes, warrants detailed research about the proximate mechanisms underlying decision-making. Our aim here is to focus on the potential role of neuroendocrine mechanisms on the regulation of the expression of cooperative behaviour in vertebrates. We first provide a brief introduction into the neuroendocrine basis of social behaviour. We then evaluate how hormones may influence known cognitive modules that are involved in decision-making processes that may lead to cooperative behaviour. Based on this evaluation, we will discuss specific examples of how hormones may contribute to the variability of cooperative behaviour at three different levels: (i) within an individual; (ii) between individuals and (iii) between species. We hope that these ideas spur increased research on the behavioural endocrinology of cooperation. PMID:20679116

  18. Behavioural genetics and temperament.

    PubMed

    Plomin, R

    1982-01-01

    Three recent developments in behavioural genetics are relevant to temperament research. First, the search for genetic influences on temperament has been frustrated by the finding that twin studies using self-report and parental rating instruments detect a genetic influence for all personality traits whereas twin studies using objective assessments rarely find a genetic influence. Secondly, environmental influences salient to temperament appear to operate in such a way as to make members of a family (siblings, for example) as different from one another as are individuals in different families. The importance of such 'E1', or non-shared, environmental influences suggests the need for studies of more than one child per family. Thirdly, adoption studies are needed to complement the extensive research on temperament in twins. In addition to its usefulness in isolating genetic influences, the adoption design can study environmental influence devoid of the confounding effects of hereditary influences; it can also isolate interactions between genotypes and environments. Preliminary results from the Colorado Adoption Project show little relationship between the temperaments of adopted and non-adopted one-year-olds and the personality characteristics of thier parents. Measures of the home and family environment did not relate to infant temperament, and no genotype-environment interaction was detected.

  19. Beyond behavioural and dynamic therapy.

    PubMed

    Murray, E J

    1983-06-01

    While historically major philosophical differences between the behavioural and dynamic approaches to therapy have existed, there is no necessary connection between metabeliefs and specific intervention techniques. Behavioural techniques can be used within a tragic vision of life and some psychoanalysts have a comic vision. Both camps want to achieve both objective and subjective changes but differ on how to achieve this. What is needed is a new, higher order theory that goes beyond both camps to help us understand the connections between cognitive, affective, and behavioural systems.

  20. How coupling determines the entrainment of circadian clocks

    NASA Astrophysics Data System (ADS)

    Bordyugov, G.; Granada, A. E.; Herzel, H.

    2011-08-01

    Autonomous circadian clocks drive daily rhythms in physiology and behaviour. A network of coupled neurons, the suprachiasmatic nucleus (SCN), serves as a robust self-sustained circadian pacemaker. Synchronization of this timer to the environmental light-dark cycle is crucial for an organism's fitness. In a recent theoretical and experimental study it was shown that coupling governs the entrainment range of circadian clocks. We apply the theory of coupled oscillators to analyse how diffusive and mean-field coupling affects the entrainment range of interacting cells. Mean-field coupling leads to amplitude expansion of weak oscillators and, as a result, reduces the entrainment range. We also show that coupling determines the rigidity of the synchronized SCN network, i.e. the relaxation rates upon perturbation. Our simulations and analytical calculations using generic oscillator models help to elucidate how coupling determines the entrainment of the SCN. Our theoretical framework helps to interpret experimental data.

  1. Understanding individual routing behaviour.

    PubMed

    Lima, Antonio; Stanojevic, Rade; Papagiannaki, Dina; Rodriguez, Pablo; González, Marta C

    2016-03-01

    Knowing how individuals move between places is fundamental to advance our understanding of human mobility (González et al. 2008 Nature 453, 779-782. (doi:10.1038/nature06958)), improve our urban infrastructure (Prato 2009 J. Choice Model. 2, 65-100. (doi:10.1016/S1755-5345(13)70005-8)) and drive the development of transportation systems. Current route-choice models that are used in transportation planning are based on the widely accepted assumption that people follow the minimum cost path (Wardrop 1952 Proc. Inst. Civ. Eng. 1, 325-362. (doi:10.1680/ipeds.1952.11362)), despite little empirical support. Fine-grained location traces collected by smart devices give us today an unprecedented opportunity to learn how citizens organize their travel plans into a set of routes, and how similar behaviour patterns emerge among distinct individual choices. Here we study 92 419 anonymized GPS trajectories describing the movement of personal cars over an 18-month period. We group user trips by origin-destination and we find that most drivers use a small number of routes for their routine journeys, and tend to have a preferred route for frequent trips. In contrast to the cost minimization assumption, we also find that a significant fraction of drivers' routes are not optimal. We present a spatial probability distribution that bounds the route selection space within an ellipse, having the origin and the destination as focal points, characterized by high eccentricity independent of the scale. While individual routing choices are not captured by path optimization, their spatial bounds are similar, even for trips performed by distinct individuals and at various scales. These basic discoveries can inform realistic route-choice models that are not based on optimization, having an impact on several applications, such as infrastructure planning, routing recommendation systems and new mobility solutions. PMID:26962031

  2. Understanding individual routing behaviour.

    PubMed

    Lima, Antonio; Stanojevic, Rade; Papagiannaki, Dina; Rodriguez, Pablo; González, Marta C

    2016-03-01

    Knowing how individuals move between places is fundamental to advance our understanding of human mobility (González et al. 2008 Nature 453, 779-782. (doi:10.1038/nature06958)), improve our urban infrastructure (Prato 2009 J. Choice Model. 2, 65-100. (doi:10.1016/S1755-5345(13)70005-8)) and drive the development of transportation systems. Current route-choice models that are used in transportation planning are based on the widely accepted assumption that people follow the minimum cost path (Wardrop 1952 Proc. Inst. Civ. Eng. 1, 325-362. (doi:10.1680/ipeds.1952.11362)), despite little empirical support. Fine-grained location traces collected by smart devices give us today an unprecedented opportunity to learn how citizens organize their travel plans into a set of routes, and how similar behaviour patterns emerge among distinct individual choices. Here we study 92 419 anonymized GPS trajectories describing the movement of personal cars over an 18-month period. We group user trips by origin-destination and we find that most drivers use a small number of routes for their routine journeys, and tend to have a preferred route for frequent trips. In contrast to the cost minimization assumption, we also find that a significant fraction of drivers' routes are not optimal. We present a spatial probability distribution that bounds the route selection space within an ellipse, having the origin and the destination as focal points, characterized by high eccentricity independent of the scale. While individual routing choices are not captured by path optimization, their spatial bounds are similar, even for trips performed by distinct individuals and at various scales. These basic discoveries can inform realistic route-choice models that are not based on optimization, having an impact on several applications, such as infrastructure planning, routing recommendation systems and new mobility solutions.

  3. Characterisation of chocolate eating behaviour.

    PubMed

    Carvalho-da-Silva, A M; Van Damme, I; Wolf, B; Hort, J

    2011-10-24

    Knowledge concerning variation in chocolate eating behaviour amongst consumers, and the impact that differences in the physical properties of chocolate could have on such behaviour is limited. The eating behaviour of individuals, consuming two chocolate samples (A and B), of comparable melt viscosity but with different textural attributes, was investigated. Surface electromyography (sEMG) was used to evaluate masticator muscle activity and electroglottography (EGG) was used to record swallowing events. Results showed that observed differences in mouthcoating affected the in-mouth residence time: chocolate A, perceived as more mouthcoating, showed an increased total chewing time and time of last swallow. Key differences across subjects were: time and number of chews, time of last swallow and total number of swallows. Subjects were grouped into three clusters of eating behaviour characterised as, "fast chewers", "thorough chewers" and "suckers". The main differences between clusters were the time chocolate was kept in mouth, chew rate and muscle work.

  4. Measuring risky adolescent cycling behaviour.

    PubMed

    Feenstra, Hans; Ruiter, Robert A C; Schepers, Jan; Peters, Gjalt-Jorn; Kok, Gerjo

    2011-09-01

    Adolescents are at a greater risk of being involved in traffic accidents than most other age groups, even before they start driving cars. This article aims to determine the factor structure of a self-report questionnaire measuring adolescent risky cycling behaviour, the ACBQ (Adolescent Cycling Behaviour Questionnaire). The questionnaire's structure was based on the widely used Driver Behaviour Questionnaire (DBQ). A sample of secondary school students (N = 1749; age range: 13-18 years) filled out the questionnaire. Factor analysis revealed a three-factor structure underlying the questionnaire, which was confirmed on two equally large portions of the entire sample. These three underlying factors were identified as errors, common violations and exceptional violations. The ACBQ is a useful instrument for measuring adolescents' risky cycling behaviour.

  5. Collective behaviour across animal species

    NASA Astrophysics Data System (ADS)

    Delellis, Pietro; Polverino, Giovanni; Ustuner, Gozde; Abaid, Nicole; Macrì, Simone; Bollt, Erik M.; Porfiri, Maurizio

    2014-01-01

    We posit a new geometric perspective to define, detect, and classify inherent patterns of collective behaviour across a variety of animal species. We show that machine learning techniques, and specifically the isometric mapping algorithm, allow the identification and interpretation of different types of collective behaviour in five social animal species. These results offer a first glimpse at the transformative potential of machine learning for ethology, similar to its impact on robotics, where it enabled robots to recognize objects and navigate the environment.

  6. Reconsidering the Sedentary Behaviour Paradigm

    PubMed Central

    Maher, Carol; Olds, Tim; Mire, Emily; Katzmarzyk, Peter T.

    2014-01-01

    Aims Recent literature has posed sedentary behaviour as an independent entity to physical inactivity. This study investigated whether associations between sedentary behaviour and cardio-metabolic biomarkers remain when analyses are adjusted for total physical activity. Methods Cross-sectional analyses were undertaken on 4,618 adults from the 2003/04 and 2005/06 U.S. National Health and Nutrition Examination Survey. Minutes of sedentary behaviour and moderate-to-vigorous physical activity (MVPA), and total physical activity (total daily accelerometer counts minus counts accrued during sedentary minutes) were determined from accelerometry. Associations between sedentary behaviour and cardio-metabolic biomarkers were examined using linear regression. Results Results showed that sedentary behaviour was detrimentally associated with 8/11 cardio-metabolic biomarkers when adjusted for MVPA. However, when adjusted for total physical activity, the associations effectively disappeared, except for C-reactive protein, which showed a very small, favourable association (β = −0.06) and triglycerides, which showed a very small, detrimental association (β = 0.04). Standardised betas suggested that total physical activity was consistently, favourably associated with cardio-metabolic biomarkers (9/11 biomarkers, standardized β = 0.08–0.30) while sedentary behaviour was detrimentally associated with just 1 biomarker (standardized β = 0.12). Conclusion There is virtually no association between sedentary behaviour and cardio-metabolic biomarkers once analyses are adjusted for total physical activity. This suggests that sedentary behaviour may not have health effects independent of physical activity. PMID:24454968

  7. The Problem Behaviour Checklist: short scale to assess challenging behaviours

    PubMed Central

    Nagar, Jessica; Evans, Rosie; Oliver, Patricia; Bassett, Paul; Liedtka, Natalie; Tarabi, Aris

    2016-01-01

    Background Challenging behaviour, especially in intellectual disability, covers a wide range that is in need of further evaluation. Aims To develop a short but comprehensive instrument for all aspects of challenging behaviour. Method In the first part of a two-stage enquiry, a 28-item scale was constructed to examine the components of challenging behaviour. Following a simple factor analysis this was developed further to create a new short scale, the Problem Behaviour Checklist (PBCL). The scale was subsequently used in a randomised controlled trial and tested for interrater reliability. Scores were also compared with a standard scale, the Modified Overt Aggression Scale (MOAS). Results Seven identified factors – personal violence, violence against property, self-harm, sexually inappropriate, contrary, demanding and disappearing behaviour – were scored on a 5-point scale. A subsequent factor analysis with the second population showed demanding, violent and contrary behaviour to account for most of the variance. Interrater reliability using weighted kappa showed good agreement (0.91; 95% CI 0.83–0.99). Good agreement was also shown with scores on the MOAS and a score of 1 on the PBCL showed high sensitivity (97%) and specificity (85%) for a threshold MOASscore of 4. Conclusions The PBCL appears to be a suitable and practical scale for assessing all aspects of challenging behaviour. Declaration of interest None. Copyright and usage © 2016 The Royal College of Psychiatrists. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) licence. PMID:27703753

  8. 4 Hz oscillations synchronize prefrontal-amygdala circuits during fear behaviour

    PubMed Central

    Karalis, Nikolaos; Dejean, Cyril; Chaudun, Fabrice; Khoder, Suzana; Rozeske, Robert R.; Wurtz, Hélène; Bagur, Sophie; Benchenane, Karim; Sirota, Anton; Courtin, Julien; Herry, Cyril

    2016-01-01

    Fear expression relies on the coordinated activity of prefrontal and amygdala circuits, yet the mechanisms allowing long-range network synchronization during fear remain unknown. Using a combination of extracellular recordings, pharmacological, and optogenetic manipulations we report that freezing, a behavioural expression of fear, temporally coincides with the development of sustained, internally generated 4 Hz oscillations within prefrontal-amygdala circuits. 4 Hz oscillations predict freezing onset and offset and synchronize prefrontal-amygdala circuits. Optogenetic induction of prefrontal 4 Hz oscillations coordinates prefrontal-amygdala activity and elicits fear behaviour. These results unravel a novel sustained oscillatory mechanism mediating prefrontal-amygdala coupling during fear behaviour. PMID:26878674

  9. Neural mechanisms underlying the evolvability of behaviour

    PubMed Central

    Katz, Paul S.

    2011-01-01

    The complexity of nervous systems alters the evolvability of behaviour. Complex nervous systems are phylogenetically constrained; nevertheless particular species-specific behaviours have repeatedly evolved, suggesting a predisposition towards those behaviours. Independently evolved behaviours in animals that share a common neural architecture are generally produced by homologous neural structures, homologous neural pathways and even in the case of some invertebrates, homologous identified neurons. Such parallel evolution has been documented in the chromatic sensitivity of visual systems, motor behaviours and complex social behaviours such as pair-bonding. The appearance of homoplasious behaviours produced by homologous neural substrates suggests that there might be features of these nervous systems that favoured the repeated evolution of particular behaviours. Neuromodulation may be one such feature because it allows anatomically defined neural circuitry to be re-purposed. The developmental, genetic and physiological mechanisms that contribute to nervous system complexity may also bias the evolution of behaviour, thereby affecting the evolvability of species-specific behaviour. PMID:21690127

  10. Cosmology of bigravity with doubly coupled matter

    SciTech Connect

    Comelli, D.; Crisostomi, M.; Koyama, K.; Pilo, L.; Tasinato, G.

    2015-04-20

    We study cosmology in the bigravity formulation of the dRGT model where matter couples to both metrics. At linear order in perturbation theory two mass scales emerge: an hard one from the dRGT potential, and an environmental dependent one from the coupling of bigravity with matter. At early time, the dynamics is dictated by the second mass scale which is of order of the Hubble scale. The set of gauge invariant perturbations that couples to matter follow closely the same behaviour as in GR. The remaining perturbations show no issue in the scalar sector, while problems arise in the tensor and vector sectors. During radiation domination, a tensor mode grows power-like at super-horizon scales. More dangerously, the only propagating vector mode features an exponential instability on sub-horizon scales. We discuss the consequences of such instabilities and speculate on possible ways to deal with them.

  11. Cosmology of bigravity with doubly coupled matter

    NASA Astrophysics Data System (ADS)

    Comelli, D.; Crisostomi, M.; Koyama, K.; Pilo, L.; Tasinato, G.

    2015-04-01

    We study cosmology in the bigravity formulation of the dRGT model where matter couples to both metrics. At linear order in perturbation theory two mass scales emerge: an hard one from the dRGT potential, and an environmental dependent one from the coupling of bigravity with matter. At early time, the dynamics is dictated by the second mass scale which is of order of the Hubble scale. The set of gauge invariant perturbations that couples to matter follow closely the same behaviour as in GR . The remaining perturbations show no issue in the scalar sector, while problems arise in the tensor and vector sectors. During radiation domination, a tensor mode grows power-like at super-horizon scales. More dangerously, the only propagating vector mode features an exponential instability on sub-horizon scales. We discuss the consequences of such instabilities and speculate on possible ways to deal with them.

  12. Best behaviour? Ontologies and the formal description of animal behaviour.

    PubMed

    Gkoutos, Georgios V; Hoehndorf, Robert; Tsaprouni, Loukia; Schofield, Paul N

    2015-10-01

    The development of ontologies for describing animal behaviour has proved to be one of the most difficult of all scientific knowledge domains. Ranging from neurological processes to human emotions, the range and scope needed for such ontologies is highly challenging, but if data integration and computational tools such as automated reasoning are to be fully applied in this important area the underlying principles of these ontologies need to be better established and development needs detailed coordination. Whilst the state of scientific knowledge is always paramount in ontology and formal description framework design, this is a particular problem with neurobehavioural ontologies where our understanding of the relationship between behaviour and its underlying biophysical basis is currently in its infancy. In this commentary, we discuss some of the fundamental problems in designing and using behaviour ontologies, and present some of the best developed tools in this domain.

  13. Linking behavioural syndromes and cognition: a behavioural ecology perspective.

    PubMed

    Sih, Andrew; Del Giudice, Marco

    2012-10-01

    With the exception of a few model species, individual differences in cognition remain relatively unstudied in non-human animals. One intriguing possibility is that variation in cognition is functionally related to variation in personality. Here, we review some examples and present hypotheses on relationships between personality (or behavioural syndromes) and individual differences in cognitive style. Our hypotheses are based largely on a connection between fast-slow behavioural types (BTs; e.g. boldness, aggressiveness, exploration tendency) and cognitive speed-accuracy trade-offs. We also discuss connections between BTs, cognition and ecologically important aspects of decision-making, including sampling, impulsivity, risk sensitivity and choosiness. Finally, we introduce the notion of cognition syndromes, and apply ideas from theories on adaptive behavioural syndromes to generate predictions on cognition syndromes.

  14. Couple-centred testing and counselling for HIV serodiscordant heterosexual couples in sub-Saharan Africa.

    PubMed

    Desgrées-du-Loû, Annabel; Orne-Gliemann, Joanna

    2008-11-01

    In Africa, a large proportion of HIV infections occur within stable relationships, either because of prior infection of one of the partners or because of infidelity. In five African countries at least two-thirds of couples with at least one HIV-positive partner were HIV serodiscordant; in half of them, the woman was the HIV-positive partner. Hence, there is an urgent need to define strategies to prevent HIV transmission within couple relationships. HIV counselling and testing have largely been organised on an individual and sex-specific basis, for pregnant women in programmes for prevention of mother-to-child transmission of HIV and in STI consultations and recently male circumcision for men. A couple-centred approach to HIV counselling and testing would facilitate communication about HIV status and adoption of preventive behaviours within couples. This paper reviews what is known about HIV serodiscordance in heterosexual couples in sub-Saharan Africa and what has been published about couple-centred initiatives for HIV counselling and testing since the early 1990s. Despite positive outcomes, couple-oriented programmes have not been implemented on a large scale. In order to stimulate and strengthen HIV prevention efforts, increased attention is required to promote prevention and testing and counselling for couples in stable relationships.

  15. Users of withdrawal method in the Islamic Republic of Iran: are they intending to use oral contraceptives? Applying the theory of planned behaviour.

    PubMed

    Rahnama, P; Hidarnia, A; Shokravi, F A; Kazemnejad, A; Montazeri, A; Najorkolaei, F R; Saburi, A

    2013-09-01

    Many couples in the Islamic Republic of Iran rely on coital withdrawal for contraception. The purpose of this cross-sectional study was to use the theory of planned behaviour to explore factors that influence withdrawal users' intent to switch to oral contraception (OC). Participants were 336 sexually active, married women, who were current users of withdrawal and were recruited from 5 public family planning clinics in Tehran. A questionnair included measures of the theory of planned behaviour: attitude (behavioural beliefs, outcome evaluations), subjective norms (normative beliefs, motivation to comply), perceived behaviour control, past behaviour and behavioural intention. Linear regression analyses showed that past behaviour, perceived behaviour control, attitude and subjective norms accounted for the highest percentage of total variance observed for intention to use OC (36%). Beliefs-based family planning education and counsellingshould to be designed for users of the withdrawal method.

  16. Users of withdrawal method in the Islamic Republic of Iran: are they intending to use oral contraceptives? Applying the theory of planned behaviour.

    PubMed

    Rahnama, P; Hidarnia, A; Shokravi, F A; Kazemnejad, A; Montazeri, A; Najorkolaei, F R; Saburi, A

    2013-09-01

    Many couples in the Islamic Republic of Iran rely on coital withdrawal for contraception. The purpose of this cross-sectional study was to use the theory of planned behaviour to explore factors that influence withdrawal users' intent to switch to oral contraception (OC). Participants were 336 sexually active, married women, who were current users of withdrawal and were recruited from 5 public family planning clinics in Tehran. A questionnair included measures of the theory of planned behaviour: attitude (behavioural beliefs, outcome evaluations), subjective norms (normative beliefs, motivation to comply), perceived behaviour control, past behaviour and behavioural intention. Linear regression analyses showed that past behaviour, perceived behaviour control, attitude and subjective norms accounted for the highest percentage of total variance observed for intention to use OC (36%). Beliefs-based family planning education and counsellingshould to be designed for users of the withdrawal method. PMID:24313039

  17. Sexually transmitted disease among married Zambian women: the role of male and female sexual behaviour in prevention and management.

    PubMed Central

    Morrison, C S; Sunkutu, M R; Musaba, E; Glover, L H

    1997-01-01

    OBJECTIVES: Few studies have evaluated the relation between male and female sexual behaviour and STD among married African women. The objectives of this study were to identify male and female sexual behaviour associated with female STD, and to explore whether incorporating male and female sexual behaviour and male symptoms can improve algorithms for STD management in married African women. METHODS: 99 married couples with one symptomatic member (58 males, 41 females) attending an STD clinic in Lusaka, Zambia were interviewed separately about sexual and contraceptive behaviour, and had physical examinations. Diagnostic tests for Neisseria gonorrhoeae (GC), Trichomonas vaginalis (TV), and HIV were performed. Bivariate and multivariate odds ratios for the association between sexual behaviour and STD were calculated. Predictive algorithms based on current Zambian guidelines for management of STD in women were created. RESULTS: Among women at baseline, 10% were positive for GC, 14% for TV, 52% for HIV. Female alcohol use before sex, a male's paying for sex, and a couple's having sex unprotected by condoms or spermicides were associated with female STD. Incorporation of these behaviours along with symptoms of urethral discharge and dysuria among husbands increased the predictive ability of algorithms for management of STD in women. CONCLUSIONS: The addition of male and female sexual behaviour and male STD symptoms to diagnostic algorithms for female STD should be explored in other settings. Both husbands' and wives' behaviour independently predict STD in these women; risk reduction programmes should target both men's and women's sexual behaviour. PMID:9582483

  18. Reward, context, and human behaviour.

    PubMed

    Blaukopf, Clare L; DiGirolamo, Gregory J

    2007-01-01

    Animal models of reward processing have revealed an extensive network of brain areas that process different aspects of reward, from expectation and prediction to calculation of relative value. These results have been confirmed and extended in human neuroimaging to encompass secondary rewards more unique to humans, such as money. The majority of the extant literature covers the brain areas associated with rewards whilst neglecting analysis of the actual behaviours that these rewards generate. This review strives to redress this imbalance by illustrating the importance of looking at the behavioural outcome of rewards and the context in which they are produced. Following a brief review of the literature of reward-related activity in the brain, we examine the effect of reward context on actions. These studies reveal how the presence of reward vs. reward and punishment, or being conscious vs. unconscious of reward-related actions, differentially influence behaviour. The latter finding is of particular importance given the extent to which animal models are used in understanding the reward systems of the human mind. It is clear that further studies are needed to learn about the human reaction to reward in its entirety, including any distinctions between conscious and unconscious behaviours. We propose that studies of reward entail a measure of the animal's (human or nonhuman) knowledge of the reward and knowledge of its own behavioural outcome to achieve that reward. PMID:17619748

  19. Habit versus planned behaviour: a field experiment.

    PubMed

    Verplanken, B; Aarts, H; van Knippenberg, A; Moonen, A

    1998-03-01

    A field experiment investigated the prediction and change in repeated behaviour in the domain of travel mode choices. Car use during seven days was predicted from habit strength (measured by self-reported frequency of past behaviour, as well as by a more covert measure based on personal scripts incorporating the behaviour), and antecedents of behaviour as conceptualized in the theory of planned behaviour (attitude, subjective norm, perceived behavioural control and behavioural intention). Both habit measures predicted behaviour in addition to intention and perceived control. Significant habit x intention interactions indicated that intentions were only significantly related to behaviour when habit was weak, whereas no intention-behaviour relation existed when habit was strong. During the seven-day registration of behaviour, half of the respondents were asked to think about the circumstances under which the behaviour was executed. Compared to control participants, the behaviour of experimental participants was more strongly related to their previously expressed intentions. However, the habit-behaviour relation was unaffected. The results demonstrate that, although external incentives may increase the enactment of intentions, habits set boundary conditions for the applicability of the theory of planned behaviour. PMID:9554090

  20. Gaze behaviour in hereditary prosopagnosia.

    PubMed

    Schwarzer, Gudrun; Huber, Susanne; Grüter, Martina; Grüter, Thomas; Gross, Cornelia; Hipfel, Melanie; Kennerknecht, Ingo

    2007-09-01

    Prosopagnosia is the inability to recognize someone by the face alone in the absence of sensory or intellectual impairment. In contrast to the acquired form of prosopagnosia we studied the congenital form. Since we could recently show that this form is inherited as a simple monogenic trait we called it hereditary form. To determine whether not only face recognition and neuronal processing but also the perceptual acquisition of facial information is specific to prosopagnosia, we studied the gaze behaviour of four hereditary prosopagnosics in comparison to matched control subjects. This rarely studied form of prosopagnosia ensures that deficits are limited to face recognition. Whereas the control participants focused their gaze on the central facial features, the hereditary prosopagnosics showed a significantly different gaze behaviour. They had a more dispersed gaze and also fixated external facial features. Thus, the face recognition impairment of the hereditary prosopagnosics is reflected in their gaze behaviour.

  1. Dynamic behaviour of "Collapsible" concrete

    NASA Astrophysics Data System (ADS)

    Caverzan, Alessio; Lamperti Tornaghi, Marco G. L.; Peroni, Marco; Solomos, George

    2015-09-01

    In this work a particular cement composite material for protection of structures and infrastructures against accidental actions, such as blast or impact, has been investigated. An experimental procedure has been developed in order to assess static and dynamic behaviour of energy absorbing cementitious composites. The granular cementitious composite has been studied focusing attention to compressive strength, high deformation and energy dissipation capacity which are important characteristics for an absorber material. An experimental characterization of the material behaviour under compressive static and dynamic loadings has been carried out. Different deformation velocities have been studied in order to define the material behaviour in a wide range of strain rates. The velocity range up to 0.1 m/s is investigated by means of a universal servo-hydraulic MTS 50 kN testing machine. Some preliminary results have been reported and discussed in the present work.

  2. Childhood obesity and eating behaviour.

    PubMed

    Obregón, Ana María; Pettinelli, Paulina P; Santos, Jose Luis

    2015-05-01

    The prevalence of childhood obesity has increased substantially in the recent decade as a result of the reduction in physical activity and the availability of high-fat and high-energy-density foods which the paediatric population faces daily. Although children are highly exposed to these foods, there is a wide variation in body weight, suggesting the presence of different patterns of response to an "obesogenic" environment. This wide variability from the point of view of eating behaviour involves a number of social issues (e.g., food availability, cost) as well as genuine behavioural traits such as the response to satiety, energy compensation, eating rate, responsiveness to food, food reward and dietary preferences. This article reviews the main physiological variables related to energy intake affecting eating behaviour in the paediatric population. PMID:25389988

  3. Anomalous basal ganglia connectivity and obsessive–compulsive behaviour in patients with Prader Willi syndrome

    PubMed Central

    Pujol, Jesus; Blanco-Hinojo, Laura; Esteba-Castillo, Susanna; Caixàs, Assumpta; Harrison, Ben J.; Bueno, Marta; Deus, Joan; Rigla, Mercedes; Macià, Dídac; Llorente-Onaindia, Jone; Novell-Alsina, Ramón

    2016-01-01

    Background Prader Willi syndrome is a genetic disorder with a behavioural expression characterized by the presence of obsessive–compulsive phenomena ranging from elaborate obsessive eating behaviour to repetitive skin picking. Obsessive–compulsive disorder (OCD) has been recently associated with abnormal functional coupling between the frontal cortex and basal ganglia. We have tested the potential association of functional connectivity anomalies in basal ganglia circuits with obsessive–compulsive behaviour in patients with Prader Willi syndrome. Methods We analyzed resting-state functional MRI in adult patients and healthy controls. Whole-brain functional connectivity maps were generated for the dorsal and ventral aspects of the caudate nucleus and putamen. A selected obsessive–compulsive behaviour assessment included typical OCD compulsions, self picking and obsessive eating behaviour. Results We included 24 adults with Prader Willi syndrome and 29 controls in our study. Patients with Prader Willi syndrome showed abnormal functional connectivity between the prefrontal cortex and basal ganglia and within subcortical structures that correlated with the presence and severity of obsessive–compulsive behaviours. In addition, abnormally heightened functional connectivity was identified in the primary sensorimotor cortex–putamen loop, which was strongly associated with self picking. Finally, obsessive eating behaviour correlated with abnormal functional connectivity both within the basal ganglia loops and between the striatum and the hypothalamus and the amygdala. Limitations Limitations of the study include the difficulty in evaluating the nature of content of obsessions in patients with Prader Willi Syndrome and the risk of excessive head motion artifact on brain imaging. Conclusion Patients with Prader Willi syndrome showed broad functional connectivity anomalies combining prefrontal loop alterations characteristic of OCD with 1) enhanced coupling in the

  4. Simulations of Edge Effect in 1D Spin Crossover Compounds by Atom-Phonon Coupling Model

    NASA Astrophysics Data System (ADS)

    Linares, J.; Chiruta, D.; Jureschi, C. M.; Alayli, Y.; Turcu, C. O.; Dahoo, P. R.

    2016-08-01

    We used the atom-phonon coupling model to explain and illustrate the behaviour of a linear nano-chain of molecules. The analysis of the system's behaviour was performed using Free Energy method, and by applying Monte Carlo Metropolis (MCM) method which take into account the phonon contribution. In particular we tested both the MCM algorithm and the dynamic-matrix method and we expose how the thermal behaviour of a 1D spin crossover system varies as a function of different factors. Furthermore we blocked the edge atoms of the chain in its high spin state to study the effect on the system's behaviour.

  5. Collective behaviour across animal species.

    PubMed

    DeLellis, Pietro; Polverino, Giovanni; Ustuner, Gozde; Abaid, Nicole; Macrì, Simone; Bollt, Erik M; Porfiri, Maurizio

    2014-01-01

    We posit a new geometric perspective to define, detect, and classify inherent patterns of collective behaviour across a variety of animal species. We show that machine learning techniques, and specifically the isometric mapping algorithm, allow the identification and interpretation of different types of collective behaviour in five social animal species. These results offer a first glimpse at the transformative potential of machine learning for ethology, similar to its impact on robotics, where it enabled robots to recognize objects and navigate the environment. PMID:24430561

  6. Collective behaviour across animal species

    PubMed Central

    DeLellis, Pietro; Polverino, Giovanni; Ustuner, Gozde; Abaid, Nicole; Macrì, Simone; Bollt, Erik M.; Porfiri, Maurizio

    2014-01-01

    We posit a new geometric perspective to define, detect, and classify inherent patterns of collective behaviour across a variety of animal species. We show that machine learning techniques, and specifically the isometric mapping algorithm, allow the identification and interpretation of different types of collective behaviour in five social animal species. These results offer a first glimpse at the transformative potential of machine learning for ethology, similar to its impact on robotics, where it enabled robots to recognize objects and navigate the environment. PMID:24430561

  7. Theories of behaviour and behaviour change across the social and behavioural sciences: a scoping review

    PubMed Central

    Davis, Rachel; Campbell, Rona; Hildon, Zoe; Hobbs, Lorna; Michie, Susan

    2015-01-01

    Interventions to change health-related behaviours typically have modest effects and may be more effective if grounded in appropriate theory. Most theories applied to public health interventions tend to emphasise individual capabilities and motivation, with limited reference to context and social factors. Intervention effectiveness may be increased by drawing on a wider range of theories incorporating social, cultural and economic factors that influence behaviour. The primary aim of this paper is to identify theories of behaviour and behaviour change of potential relevance to public health interventions across four scientific disciplines: psychology, sociology, anthropology and economics. We report in detail the methodology of our scoping review used to identify these theories including which involved a systematic search of electronic databases, consultation with a multidisciplinary advisory group, web searching, searching of reference lists and hand searching of key behavioural science journals. Of secondary interest we developed a list of agreed criteria for judging the quality of the theories. We identified 82 theories and 9 criteria for assessing theory quality. The potential relevance of this wide-ranging number of theories to public health interventions and the ease and usefulness of evaluating the theories in terms of the quality criteria are however yet to be determined. PMID:25104107

  8. Theories of behaviour and behaviour change across the social and behavioural sciences: a scoping review.

    PubMed

    Davis, Rachel; Campbell, Rona; Hildon, Zoe; Hobbs, Lorna; Michie, Susan

    2015-01-01

    Interventions to change health-related behaviours typically have modest effects and may be more effective if grounded in appropriate theory. Most theories applied to public health interventions tend to emphasise individual capabilities and motivation, with limited reference to context and social factors. Intervention effectiveness may be increased by drawing on a wider range of theories incorporating social, cultural and economic factors that influence behaviour. The primary aim of this paper is to identify theories of behaviour and behaviour change of potential relevance to public health interventions across four scientific disciplines: psychology, sociology, anthropology and economics. We report in detail the methodology of our scoping review used to identify these theories including which involved a systematic search of electronic databases, consultation with a multidisciplinary advisory group, web searching, searching of reference lists and hand searching of key behavioural science journals. Of secondary interest we developed a list of agreed criteria for judging the quality of the theories. We identified 82 theories and 9 criteria for assessing theory quality. The potential relevance of this wide-ranging number of theories to public health interventions and the ease and usefulness of evaluating the theories in terms of the quality criteria are however yet to be determined.

  9. Theories of behaviour and behaviour change across the social and behavioural sciences: a scoping review.

    PubMed

    Davis, Rachel; Campbell, Rona; Hildon, Zoe; Hobbs, Lorna; Michie, Susan

    2015-01-01

    Interventions to change health-related behaviours typically have modest effects and may be more effective if grounded in appropriate theory. Most theories applied to public health interventions tend to emphasise individual capabilities and motivation, with limited reference to context and social factors. Intervention effectiveness may be increased by drawing on a wider range of theories incorporating social, cultural and economic factors that influence behaviour. The primary aim of this paper is to identify theories of behaviour and behaviour change of potential relevance to public health interventions across four scientific disciplines: psychology, sociology, anthropology and economics. We report in detail the methodology of our scoping review used to identify these theories including which involved a systematic search of electronic databases, consultation with a multidisciplinary advisory group, web searching, searching of reference lists and hand searching of key behavioural science journals. Of secondary interest we developed a list of agreed criteria for judging the quality of the theories. We identified 82 theories and 9 criteria for assessing theory quality. The potential relevance of this wide-ranging number of theories to public health interventions and the ease and usefulness of evaluating the theories in terms of the quality criteria are however yet to be determined. PMID:25104107

  10. The Work-Centered Couple.

    ERIC Educational Resources Information Center

    Sperry, Len; Carlson, Jon

    1991-01-01

    Sketches taxonomy of work-centered couple. Briefly describes five couple types: the dual-career couple, the commuting couple, the military couple, the executive couple, and the family business couple. Notes that issues of work and career can greatly impact the lives of these couples. Encourages family psychology to further explore this area of…

  11. Behavioural Precursors and HIV Testing Behaviour among African American Women

    ERIC Educational Resources Information Center

    Uhrig, Jennifer D.; Davis, Kevin C.; Rupert, Doug; Fraze, Jami

    2012-01-01

    Objective: To examine whether there is an association between knowledge, attitudes and beliefs, reported intentions to get an HIV test, and reported HIV testing behaviour at a later date among a sample of African American women. Design: Secondary analysis of data collected from October 2007 through March 2008 for a randomized controlled experiment…

  12. Diverse coupling of neurons to populations in sensory cortex

    PubMed Central

    Okun, Michael; Steinmetz, Nicholas; Cossell, Lee; Iacaruso, M. Florencia; Ko, Ho; Barthó, Péter; Moore, Tirin; Hofer, Sonja B.; Mrsic-Flogel, Thomas D.

    2015-01-01

    A large population of neurons can in principle produce an astronomical number of distinct firing patterns. In cortex however, these patterns lie in a space of lower dimension1-4, as if individual neurons were “obedient members of a huge orchestra”5. Here we use recordings from the visual cortex of mouse and monkey to investigate the relationship between individual neurons and the population, and to establish the underlying circuit mechanisms. We show that neighbouring neurons can differ in their coupling to the overall firing of the population, ranging from strongly coupled “choristers” to weakly coupled “soloists”. Population coupling is largely independent of sensory preferences, and it is a fixed cellular attribute, invariant to stimulus conditions. Neurons with high population coupling are more strongly affected by non-sensory behavioural variables such as motor intention. Population coupling reflects a causal relationship, predicting a neuron’s response to optogenetically-driven increases in local activity. Moreover, population coupling indicates synaptic connectivity: a neuron’s population coupling, measured in vivo, predicted subsequent in vitro estimates of the number of synapses received from its neighbours. Finally, population coupling provides a compact summary of population activity: knowledge of the population couplings of N neurons predicts a substantial portion of their N2 pairwise correlations. Population coupling therefore represents a novel, simple measure that characterises each neuron’s relationship to a larger population, explaining seemingly complex network firing patterns in terms of basic circuit variables. PMID:25849776

  13. Towards a general theory of driver behaviour.

    PubMed

    Fuller, Ray

    2005-05-01

    Taylor [Taylor, D.H., 1964. Drivers' galvanic skin response and the risk of accident. Ergonomics 7, 439-451] argued that drivers attempt to maintain a constant level of anxiety when driving which Wilde [Wilde, G.J.S., 1982. The theory of risk homeostasis: implications for safety and health. Risk Anal. 2, 209-225] interpreted to be coupled to subjective estimates of the probability of collision. This theoretical paper argues that what drivers attempt to maintain is a level of task difficulty. Naatanen and Summala [Naatanen, R., Summala, H., 1976. Road User Behaviour and Traffic Accidents. North Holland/Elsevier, Amsterdam, New York] similarly rejected the concept of statistical risk as a determinant of driver behaviour, but in so doing fell back on the learning process to generate a largely automatised selection of appropriate safety margins. However it is argued here that driver behaviour cannot be acquired and executed principally in such S-R terms. The concept of task difficulty is elaborated within the framework of the task-capability interface (TCI) model, which describes the dynamic interaction between the determinants of task demand and driver capability. It is this interaction which produces different levels of task difficulty. Implications of the model are discussed regarding variation in performance, resource allocation, hierarchical decision-making and the interdependence of demand and capability. Task difficulty homeostasis is proposed as a key sub-goal in driving and speed choice is argued to be the primary solution to the problem of keeping task difficulty within selected boundaries. The relationship between task difficulty and mental workload and calibration is clarified. Evidence is cited in support of the TCI model, which clearly distinguishes task difficulty from estimates of statistical risk. However, contrary to expectation, ratings of perceived risk depart from ratings of statistical risk but track difficulty ratings almost perfectly. It now

  14. Glycans pattern the phase behaviour of lipid membranes

    NASA Astrophysics Data System (ADS)

    Subramaniam, Anand Bala; Guidotti, Guido; Manoharan, Vinothan N.; Stone, Howard A.

    2013-02-01

    Hydrated networks of glycans (polysaccharides)—in the form of cell walls, periplasms or gel-like matrices—are ubiquitously present adjacent to cellular plasma membranes. Yet, despite their abundance, the function of glycans in the extracellular milieu is largely unknown. Here we show that the spatial configuration of glycans controls the phase behaviour of multiphase model lipid membranes: inhomogeneous glycan networks stabilize large lipid domains at the characteristic length scale of the network, whereas homogeneous networks suppress macroscopic lipid phase separation. We also find that glycan-patterned phase separation is thermally reversible—thus indicating that the effect is thermodynamic rather than kinetic—and that phase patterning probably results from a preferential interaction of glycans with ordered lipid phases. These findings have implications for membrane-mediated transport processes, potentially rationalize long-standing observations that differentiate the behaviour of native and model membranes and may indicate an intimate coupling between cellular lipidomes and glycomes.

  15. Biorhythm in Couple Counseling

    ERIC Educational Resources Information Center

    Araoz, Daniel L.

    1977-01-01

    Twelve couples in marital counseling were studied during 12 months on the basis of their biorhythms. For each couple a compatibility percentage was obtained. It was found that difficulties in their interaction correlated highly with dissonance in their biorhythms. (Author)

  16. The physiological cost of velocity coupling during tennis groundstrokes.

    PubMed

    Cooke, Karl; Davey, Polly R

    2007-05-01

    Velocity coupling denotes a perceptual motor behaviour known to occur during coincidence timing tasks. Individuals have been shown to increase their effector limb speed with increases in stimulus speed during interceptive tasks. However, little is known about the physiological effects of velocity coupling. The aim of this study was to determine the physiological cost of velocity coupling during tennis groundstrokes. Eight male and eight female competitive tennis players volunteered to perform three 4-min bouts of continuous groundstrokes against balls projected from a tennis ball machine at speeds of 18, 22, and 27 m x s(-1) (65, 79, and 97 km x h(-1)) and a frequency of 14 balls per minute, the order of which was counterbalanced. Breath-by-breath pulmonary gas exchange, heart rate, locomotion time, and limb acceleration were measured throughout each of the 4-min bouts. Capillary blood samples (for blood lactate analysis), rating of perceived exertion, and difficulty rating were taken at the end of each bout. Increasing ball speed did not influence the locomotion time between groundstrokes but did result in a bilateral increase in both the mean upper- and lower-limb acceleration (all P < 0.05). Velocity coupling behaviour increased oxygen uptake, blood lactate concentration, heart rate, rating of perceived exertion, and perceived task difficulty (all P < 0.05). It would appear, therefore, that velocity coupling influenced tennis groundstroke behaviour and indirectly modified the concurrent cardiopulmonary and metabolic responses. PMID:17454549

  17. Boundaries in Visualizing Mathematical Behaviour

    ERIC Educational Resources Information Center

    Hare, Andrew Francis

    2013-01-01

    It is surprising to students to learn that a natural combination of simple functions, the function sin(1/x), exhibits behaviour that is a great challenge to visualize. When x is large the function is relatively easy to draw; as x gets smaller the function begins to behave in an increasingly wild manner. The sin(1/x) function can serve as one of…

  18. Challenging Behaviours: Prevalence and Topographies

    ERIC Educational Resources Information Center

    Lowe, K.; Allen, D.; Jones, E.; Brophy, S.; Moore, K.; James, W.

    2007-01-01

    Background: Variations in reported prevalence of challenging behaviour indicate the need for further epidemiological research to support accurate planning of future service provision. Methods: All services providing for people with learning disabilities across seven unitary authorities, with a total population of 1.2 million, were screened to…

  19. Behaviour: Seeing heat saves energy

    NASA Astrophysics Data System (ADS)

    Steg, Linda

    2016-01-01

    Household energy conservation can help to significantly lower energy consumption. Visual cues provided by thermal imaging of heat loss in buildings are now shown to increase energy conserving behaviours and implementations among homeowners more effectively than just performing carbon footprint audits.

  20. Handbook of Emotional & Behavioural Difficulties

    ERIC Educational Resources Information Center

    Clough, Peter; Garner, Philip; Pardeck, John T.; Yuen, Francis K.O.

    2005-01-01

    The behaviour of children in primary/elementary and secondary/high schools has been a consistent source of interest and controversy since the 19th century. As education systems in First World democracies struggle to meet changing social, economic and educational conditions, one group of children has increasingly become the focus of attention.…

  1. Altruistic defence behaviours in aphids

    PubMed Central

    2010-01-01

    Background Altruistic anti-predatory behaviours pose an evolutionary problem because they are costly to the actor and beneficial to the recipients. Altruistic behaviours can evolve through indirect fitness benefits when directed toward kin. The altruistic nature of anti-predatory behaviours is often difficult to establish because the actor can obtain direct fitness benefits, or the behaviour could result from selfish coercion by others, especially in eusocial animals. Non-eusocial parthenogenetically reproducing aphids form colonies of clone-mates, which are ideal to test the altruistic nature of anti-predatory defence behaviours. Many aphids release cornicle secretions when attacked by natural enemies such as parasitoids. These secretions contain an alarm pheromone that alerts neighbours (clone-mates) of danger, thereby providing indirect fitness benefits to the actor. However, contact with cornicle secretions also hampers an attacker and could provide direct fitness to the actor. Results We tested the hypothesis that cornicle secretions are altruistic by assessing direct and indirect fitness consequences of smearing cornicle secretions onto an attacker, and by manipulating the number of clone-mates that could benefit from the behaviour. We observed parasitoids, Aphidius rhopalosiphi, foraging singly in patches of the cereal aphid Sitobion avenae of varied patch size (2, 6, and 12 aphids). Aphids that smeared parasitoids did not benefit from a reduced probability of parasitism, or increase the parasitoids' handling time. Smeared parasitoids, however, spent proportionately more time grooming and less time foraging, which resulted in a decreased host-encounter and oviposition rate within the host patch. In addition, individual smearing rate increased with the number of clone-mates in the colony. Conclusions Cornicle secretions of aphids were altruistic against parasitoids, as they provided no direct fitness benefits to secretion-releasing individuals, only indirect

  2. Collective dynamics in strongly coupled dusty plasma medium

    NASA Astrophysics Data System (ADS)

    Das, Amita; Dharodi, Vikram; Tiwari, Sanat; Tiwari

    2014-12-01

    A simplified description of dynamical response of strongly coupled medium is desirable in many contexts of physics. The dusty plasma medium can play an important role in this regard due to its uniqueness, as its dynamical response typically falls within the perceptible grasp of human senses. Furthermore, even at room temperature and normal densities it can be easily prepared to be in a strongly coupled regime. A simplified phenomenological fluid model based on the visco - elastic behaviour of the medium is often invoked to represent the collective dynamical response of a strongly coupled dusty plasma medium. The manuscript reviews the role of this particular Generalized Hydrodynamic (GHD) fluid model in capturing the collective properties exhibited by the medium. In addition the paper also provides new insights on the collective behaviour predicted by the model for the medium, in terms of coherent structures, instabilities, transport and mixing properties.

  3. Simulating behaviour change interventions based on the theory of planned behaviour: Impacts on intention and action.

    PubMed

    Fife-Schaw, Chris; Sheeran, Paschal; Norman, Paul

    2007-03-01

    The theory of planned behaviour (TPB; Ajzen, 1991) has been used extensively to predict social and health behaviours. However, a critical test of the TPB is whether interventions that increased scores on the theory's predictors would engender behaviour change. The present research deployed a novel technique in order to provide this test. Statistical simulations were conducted on data for 30 behaviours (N=211) that estimated the impact of interventions that generated maximum positive changes in attitudes, subjective norms and perceived behavioural control (PBC) on subsequent intentions and behaviour. Findings indicated that interventions that maximized TPB variables had a substantial impact on behavioural intentions. Although TPB maximization increased the proportion of the sample that performed respective behaviours by 28% compared with baseline, the behaviour of a substantial minority of the sample (26%) did not change. The research also identified several interactions among TPB variables in predicting simulated intention and behaviour scores and investigated the mediating role of intentions in predicting behaviour. PMID:17355718

  4. Inclusive Education: Teachers' Intentions and Behaviour Analysed from the Viewpoint of the Theory of Planned Behaviour

    ERIC Educational Resources Information Center

    Yan, Zi; Sin, Kuen-fung

    2014-01-01

    The theory of planned behaviour (TPB) claims that behaviour can be predicted by behavioural intention and perceived behavioural control, while behavioural intention is a function of attitude towards the behaviour, subjective norm, and perceived behavioural control. This study aims at providing explanation and prediction of teachers' inclusive…

  5. Virtual ethology of aquatic animal heterogeneous behaviours

    NASA Astrophysics Data System (ADS)

    Lim, ChenKim; Tan, KianLam

    2016-08-01

    In the virtual world, the simulation of flocking behaviour has been actively investigated since the 1980 through the boid models. However, ethology is a niche study of animal behaviour from the biological perspective that is rarely instil in the interest of the younger learners nowadays. The keystone of the research is to be able to disseminate the study of animal behaviours through the boid model with the aid of technology. Through the simulation, complex movement of animal behaviours are reproduced based on the extension of basic behaviours of boid algorithm. The techniques here are to (i) Analyse a high-level behavioural framework of motion in the animal behaviours and (ii) Evolves particles to other animal representations to portray more real-time examples of steering behaviours. Although the generality of the results is limited by the number of case study, it also supports the hypothesis that interactive simulation system of virtual ethology can aid the improvement of animal studies.

  6. Behavioural social choice: a status report

    PubMed Central

    Regenwetter, Michel; Grofman, Bernard; Popova, Anna; Messner, William; Davis-Stober, Clintin P.; Cavagnaro, Daniel R.

    2008-01-01

    Behavioural social choice has been proposed as a social choice parallel to seminal developments in other decision sciences, such as behavioural decision theory, behavioural economics, behavioural finance and behavioural game theory. Behavioural paradigms compare how rational actors should make certain types of decisions with how real decision makers behave empirically. We highlight that important theoretical predictions in social choice theory change dramatically under even minute violations of standard assumptions. Empirical data violate those critical assumptions. We argue that the nature of preference distributions in electorates is ultimately an empirical question, which social choice theory has often neglected. We also emphasize important insights for research on decision making by individuals. When researchers aggregate individual choice behaviour in laboratory experiments to report summary statistics, they are implicitly applying social choice rules. Thus, they should be aware of the potential for aggregation paradoxes. We hypothesize that such problems may substantially mar the conclusions of a number of (sometimes seminal) papers in behavioural decision research. PMID:19073478

  7. Exploring Communication Technology Behaviour of Adolescents with Cerebral Palsy in Singapore

    ERIC Educational Resources Information Center

    rasid, Nadia natasha binte mohamed; Nonis, Karen P.

    2015-01-01

    Communication among adolescents with cerebral palsy can be restricted with traditional Augmentative and Alternative Communication (AAC) device coupled with environmental and social barriers. The advance of communication technology offer solutions to reduce such barriers. Given that there is limited research in communication behaviours of…

  8. Machine analysis of facial behaviour: naturalistic and dynamic behaviour

    PubMed Central

    Pantic, Maja

    2009-01-01

    This article introduces recent advances in the machine analysis of facial expressions. It describes the problem space, surveys the problem domain and examines the state of the art. Two recent research topics are discussed with particular attention: analysis of facial dynamics and analysis of naturalistic (spontaneously displayed) facial behaviour. Scientific and engineering challenges in the field in general, and in these specific subproblem areas in particular, are discussed and recommendations for accomplishing a better facial expression measurement technology are outlined. PMID:19884145

  9. Dynamical behaviours observed on falling liquids

    NASA Astrophysics Data System (ADS)

    Brunet, Philippe; Le Grand, Nolwenn; Limat, Laurent

    2001-11-01

    We investigate dynamical behaviours of viscous liquids falling from a ceiling in various geometries : fall from a horizontal cylinder, from a circular dish, and from the bottom of a porous plate. In these differents experiments, the liquid is supplied at constant flow rate and falls under the effect of gravity. When the flow-rate is large, the flow involves one or several liquid sheets. We have studied the shape and stablity of such objects near the break-up into liquid threads : we have highlighted the similarities and differences of shapes between wakes and holes respectively generated by disturbing sheets with a wettable and a non-wettable obstacle. We put into evidence the limits of the stability criterion found by Taylor and Lin and we observe various unrecognized instabilities: hole boundary oscilations coupled with detachment of the rim surrounding the hole, propagation of a "crack" between the rim and the sheet, chessboard-like pattern of sinuous waves formed on oscillating sheets... A similar study has been performed on threads formed by sheet breaking. A single thread can develop the Rayleigh instability and breaks into droplets. A system of several threads coupled with each other by a residual film remaining on the ceiling, exhibit remarkable collective modes of column motions, that we have investigated in a circular geometry. Among other results we were able to quantify very accurately the scenario of parity breaking in this system and also the transition to temporal or spatio-temporal chaos. A two dimensional version of this system, i.e. columns formed below a porous plate is under study.

  10. Approach to Challenging Behaviour: A Family Affair

    ERIC Educational Resources Information Center

    Keen, Deb; Knox, Marie

    2004-01-01

    Over the past 30 years, research in the area of applied behaviour analysis has led to a rich knowledge and understanding of the variables that influence human behaviour. This understanding and knowledge has given rise to a range of assessment and intervention techniques that have been applied to individuals with challenging behaviour.…

  11. From Bedlam to Decorum: Improving Lunchtime Behaviour

    ERIC Educational Resources Information Center

    Aviani, Robert

    2006-01-01

    In many middle schools, poor student lunchtime behaviour is an ongoing problem. Such behaviour can have a detrimental effect on a school's climate and culture, which can in turn degrade the quality of learning that occurs in the classroom. As a result, improving students' lunchtime behaviour should be a priority for staff. One solution is to make…

  12. Student Behaviour Self-Monitoring Enabling Inclusion

    ERIC Educational Resources Information Center

    Jull, Stephen K.

    2009-01-01

    Disruptive, antisocial behaviour remains an ongoing issue for all schools, and particularly those identified as inclusive. Children who exhibit elevated levels of antisocial behaviour have an increased risk of numerous negative life consequences, including impaired social relationships, escalating aggressive behaviours, substance abuse, and school…

  13. Adolescents' protection motivation and smoking behaviour.

    PubMed

    Thrul, Johannes; Stemmler, Mark; Bühler, Anneke; Kuntsche, Emmanuel

    2013-08-01

    The protection motivation theory (PMT) is a well-known theory of behaviour change. This study tested the applicability of the sub-constructs of threat and coping appraisal in predicting adolescents' smoking-related behavioural intentions and smoking behaviour longitudinally. Adolescents (N = 494) aged 11-16 years and not currently smoking at baseline participated in the study. Predictive validity of PMT constructs was tested in a path analysis model. Self-efficacy significantly predicted behavioural intention at baseline, which significantly predicted behavioural intention at follow-up, which in turn predicted smoking behaviour at follow-up. The effect of self-efficacy on behavioural intention at follow-up was mediated by behavioural intention at baseline and the effect of self-efficacy on smoking behaviour was mediated by behavioural intention at baseline and follow-up. In conclusion, we found support for one part of the PMT, namely for the predictive validity of the coping appraisal construct self-efficacy in predicting adolescents' smoking-related behavioural intention and smoking behaviour. These results fail to support the appropriateness of the PMT's construct threat appraisal in longitudinally predicting adolescents' smoking as well as the applicability of communicating fear and negative information as preventive interventions for this target group.

  14. Short Form of the Developmental Behaviour Checklist

    ERIC Educational Resources Information Center

    Taffe, John R.; Gray, Kylie M.; Einfeld, Stewart L.; Dekker, Marielle C.; Koot, Hans M.; Emerson, Eric; Koskentausta, Terhi; Tonge, Bruce J.

    2007-01-01

    A 24-item short form of the 96-item Developmental Behaviour Checklist was developed to provide a brief measure of Total Behaviour Problem Score for research purposes. The short form Developmental Behaviour Checklist (DBC-P24) was chosen for low bias and high precision from among 100 randomly selected item sets. The DBC-P24 was developed from…

  15. Behavioural inventory of the giraffe (Giraffa camelopardalis)

    PubMed Central

    2012-01-01

    Background Numerous factors like continuous habitat reduction or fragmentation for free-ranging giraffes (Giraffa camelopardalis) as well as e.g. suboptimal housing conditions for animals in captivity might lead to behavioural alterations as part of the overall adaptation process to the changing living conditions. In order to facilitate current and future studies on giraffe behaviour, a comprehensive ethogram was compiled based on existing literature, as well as observations on giraffes in the wild (Hwange National Park, Zimbabwe; Entabeni Game Reserve, South Africa), and in captivity (National Zoological Gardens of South Africa, Pretoria). Findings The resulting ethogram lists 65 different behavioural patterns, which were described and grouped into seven categories: General activities, Abnormal repetitive behaviours, General interactions, Bull-Cow behaviour, Bull-Bull behaviour, Cow-Bull behaviour, Maternal behaviours, and Interactions by calves. The behaviours were further described regarding a presumed purpose, particularly with respect to social interactions and sexual behaviour. Contradictory descriptions from previous studies were considered and discussed in comparison with our own observations. Conclusions This ethogram provides a basis for current and future studies by suggesting a terminology which can be used for harmonizing behavioural observations, thus helping to facilitate comparability of future results. Subsequently, a better understanding of the behavioural ecology of giraffes in the wild as well as in captivity could aid future conservation efforts. PMID:23173954

  16. A Cognitive Behavioural Group Approach for Adolescents with Disruptive Behaviour in Schools

    ERIC Educational Resources Information Center

    Ruttledge, Richard A.; Petrides, K. V.

    2012-01-01

    Cognitive behavioural approaches emphasize the links between thoughts, feelings and behaviour (Greig, 2007). Previous research has indicated that these approaches are efficacious in reducing disruptive behaviour in adolescents. The aim of the current study was to provide further evaluation of cognitive behavioural group work to reduce disruptive…

  17. Heterogeneity in Antisocial Behaviours and Comorbidity with Depressed Mood: A Behavioural Genetic Approach

    ERIC Educational Resources Information Center

    Rowe, Richard; Rijsdijk, Fruhling V.; Maughan, Barbara; Eley, Thalia C.; Hosang, Georgina M.

    2008-01-01

    Background: Antisocial behaviour is often comorbid with depressed mood but is itself a collection of heterogeneous behaviours. Using a genetically informative design, we examine heterogeneity in antisocial behaviour and overlaps between different forms of antisocial behaviour with depressed mood. Methods: Data were drawn from the G1219 large-scale…

  18. Behavioural approaches to anxiety disorders.

    PubMed Central

    Drummond, L. M.

    1993-01-01

    Powerful behavioural treatments for many patients with anxiety disorders have been widely available since the 1970s. Despite this, the majority of such patients have continued to be treated with psychotrophic drugs. Recent litigation against the manufacturers of benzodiazepine drugs has made the public increasingly concerned about the prescription of anxiolytic agents. In parallel with the fall in popularity of drug treatment, advances have been made which increase the availability and applicability of behavioural treatments for these patients. This paper examines the impact of the development of self-exposure and cognitive methods on a number of common anxiety syndromes. Clinical examples of self-exposure are given to demonstrate the simplicity of the technique. PMID:8497438

  19. Investigating mothers' decisions about their child's sun-protective behaviour using the Theory of Planned Behaviour.

    PubMed

    Thomson, Courtney E; White, Katherine M; Hamilton, Kyra

    2012-10-01

    This study tested the utility of the Theory of Planned Behaviour (TPB) to predict mothers' decisions to ensure their child engages in sun-protective behaviours. Mothers (N = 162) of children aged four or five years completed standard TPB items (attitude, subjective norm, perceived behavioural control, intention) and additional variables of role construction, mothers' own sun safe behaviour, planning and past behaviour. One week later, participants (N = 116) reported their behaviour. Results found support for the TPB constructs, role construction, past behaviour and the mediating role of planning. These findings can inform strategies to prevent skin cancer.

  20. Investigating mothers' decisions about their child's sun-protective behaviour using the Theory of Planned Behaviour.

    PubMed

    Thomson, Courtney E; White, Katherine M; Hamilton, Kyra

    2012-10-01

    This study tested the utility of the Theory of Planned Behaviour (TPB) to predict mothers' decisions to ensure their child engages in sun-protective behaviours. Mothers (N = 162) of children aged four or five years completed standard TPB items (attitude, subjective norm, perceived behavioural control, intention) and additional variables of role construction, mothers' own sun safe behaviour, planning and past behaviour. One week later, participants (N = 116) reported their behaviour. Results found support for the TPB constructs, role construction, past behaviour and the mediating role of planning. These findings can inform strategies to prevent skin cancer. PMID:22253324

  1. Cannabinoids, eating behaviour, and energy homeostasis.

    PubMed

    Romero-Zerbo, Silvana Y; Bermúdez-Silva, Francisco J

    2014-01-01

    Soon after the discovery of cannabis by western societies, its psychotropic effects overshadowed its medical benefits. However, investigation into the molecular action of the main constituents of cannabis has led to the discovery of an intercellular signalling system, called the endocannabinoid system (ECS). The ECS comprises a set of molecular components, including enzymes, signalling lipids and G-protein coupled receptors, which has an outstanding role in modulating eating behaviour and energy homeostasis. Interestingly, evidence has shown that the ECS is present at the central and peripheral nervous system, modulating the function of the hypothalamus, the brain reward system and the brainstem, and coordinating the crosstalk between these brain structures and peripheral organs. Indeed, the ECS is present and functional in metabolically relevant peripheral tissues, directly modulating their physiology. In the context of a global obesity pandemic, these discoveries are highly suggestive in order to design novel pharmaceutical tools to fight obesity and related morbidities. In fact, a cannabinoid-based first generation of drugs was developed and marketed. Their failure, due to central side-effects, is leading to a second generation of these drugs unable to cross the blood-brain barrier, as well as other ECS-focused strategies that are still in the pipeline. In the next few years we will hopefully know whether such an important player in energy homeostasis can be successfully targeted without significantly affecting other vital processes related to mood and sense of well-being.

  2. Non linear behaviour of cell tensegrity models

    NASA Astrophysics Data System (ADS)

    Alippi, A.; Bettucci, A.; Biagioni, A.; Conclusio, D.; D'Orazio, A.; Germano, M.; Passeri, D.

    2012-05-01

    Tensegrity models for the cytoskeleton structure of living cells is largely used nowadays for interpreting the biochemical response of living tissues to mechanical stresses. Microtubules, microfilaments and filaments are the microscopic cell counterparts of struts (microtubules) and cables (microfilaments and filaments) in the macroscopic world: the formers oppose to compression, the latters to tension, thus yielding an overall structure, light and highly deformable. Specific cell surface receptors, such as integrins, act as the coupling elements that transmit the outside mechanical stress state into the cell body. Reversible finite deformations of tensegrity structures have been widely demonstrated experimentally and in a number of living cell simulations. In the present paper, the bistability behaviour of two general models, the linear bar oscillator and the icosahedron, is studied, as they are both obtained from mathematical simulation, the former, and from larger scale experiments, the latter. The discontinuity in the frequency response of the oscillation amplitude and the lateral bending of the resonance curves are put in evidence, as it grows larger as the driving amplitude increases, respectively.

  3. Imitation dynamics predict vaccinating behaviour.

    PubMed

    Bauch, Chris T

    2005-08-22

    There exists an interplay between vaccine coverage, disease prevalence and the vaccinating behaviour of individuals. Moreover, because of herd immunity, there is also a strategic interaction between individuals when they are deciding whether or not to vaccinate, because the probability that an individual becomes infected depends upon how many other individuals are vaccinated. To understand this potentially complex interplay, a game dynamic model is developed in which individuals adopt strategies according to an imitation dynamic (a learning process), and base vaccination decisions on disease prevalence and perceived risks of vaccines and disease. The model predicts that oscillations in vaccine uptake are more likely in populations where individuals imitate others more readily or where vaccinating behaviour is more sensitive to changes in disease prevalence. Oscillations are also more likely when the perceived risk of vaccines is high. The model reproduces salient features of the time evolution of vaccine uptake and disease prevalence during the whole-cell pertussis vaccine scare in England and Wales during the 1970s. This suggests that using game theoretical models to predict, and even manage, the population dynamics of vaccinating behaviour may be feasible.

  4. Tracking Optical and Electronic Behaviour of Quantum Contacts in Sub-Nanometre Plasmonic Cavities

    NASA Astrophysics Data System (ADS)

    Sanders, A.; Bowman, R. W.; Baumberg, J. J.

    2016-09-01

    Plasmonic interactions between two metallic tips are dynamically studied in a supercontinuum dark-field microscope and the transition between coupled and charge-transfer plasmons is directly observed in the sub-nm regime. Simultaneous measurement of the dc current, applied force, and optical scattering as the tips come together is used to determine the effects of conductive pathways within the plasmonic nano-gap. Critical conductances are experimentally identified for the first time, determining the points at which quantum tunnelling and conductive charge transport begin to influence plasmon coupling. These results advance our understanding of the relationship between conduction and plasmonics, and the fundamental quantum mechanical behaviours of plasmonic coupling.

  5. Phenomenology and treatment of behavioural addictions.

    PubMed

    Grant, Jon E; Schreiber, Liana R N; Odlaug, Brian L

    2013-05-01

    Behavioural addictions are characterized by an inability to resist an urge or drive resulting in actions that are harmful to oneself or others. Behavioural addictions share characteristics with substance and alcohol abuse, and in areas such as natural history, phenomenology, and adverse consequences. Behavioural addictions include pathological gambling, kleptomania, pyromania, compulsive buying, compulsive sexual behaviour, Internet addiction, and binge eating disorder. Few studies have examined the efficacy of pharmacological and psychological treatment for the various behavioural addictions, and therefore, currently, no treatment recommendations can be made.

  6. Genetics and criminal behaviour: recent accomplishments.

    PubMed

    Lagoa, Arlindo; Santos, Agostinho; Pinheiro, M Fátima; Magalhães, Teresa

    2009-10-01

    The past two decades have seen an explosion in research in the fields of violence and behavioural genetics. Advances in human genetics have raised the possibility that genetic mechanisms can explain various aspects of human criminal and aggressive behaviour. However, this new knowledge can pose enormous challenges concerning the moral and legal conceptions of free will and responsibility. This paper reviews the main aspects of behavioural genetics, focusing on criminal and aggressive behaviour and describes the most important genes known to influence this behaviour.

  7. Consistent behavioural traits and behavioural syndromes in pairs of the false clown anemonefish Amphiprion ocellaris.

    PubMed

    Wong, M Y L; Medina, A; Uppaluri, C; Arnold, S; Seymour, J R; Buston, P M

    2013-07-01

    Using the social clown anemonefish Amphiprion ocellaris, whether individuals exhibited consistency in activity levels, boldness and sociability in a paired context, and whether these three behavioural traits were positively correlated within a single behavioural syndrome, was investigated. The results highlight that consistent individual differences in behaviour are expressed in a social fish and suggest that consistent behavioural traits and behavioural syndromes could influence the structure and functioning of their societies.

  8. Designing interventions to change eating behaviours.

    PubMed

    Atkins, Lou; Michie, Susan

    2015-05-01

    Understanding and changing eating behaviours are central to the work of Nutrition Society members working in both research and applied settings. The present paper describes a recently published resource to guide the design of interventions to change behaviour, The Behaviour Change Wheel: A Guide to Designing Interventions (BCW Guide). This is a practical guide to intervention design that brings together recently-developed theory-based tools in behavioural science into a coherent step-by-step design process. It is based on the BCW, a synthesis of nineteen frameworks of behaviour change found in the research literature. The BCW has at its core a model of behaviour known as 'capability', 'opportunity', 'motivation' and 'behaviour'. The model recognises that behaviour is part of an interacting system involving all these components. The BCW identifies different intervention options that can be applied to changing each of the components and policies that can be adopted to deliver those intervention options. The book shows how the BCW links to theory-based frameworks to understand behaviour such as the Theoretical Domains Framework and the recently developed Behaviour Change Technique Taxonomy v1 for specifying intervention content. In essence, it shows how to link what is understood about a given behaviour to types of intervention likely to be effective and then translate this into a locally relevant intervention. In addition, the present paper sets out some principles of intervention design. PMID:25998679

  9. Response reactions: equilibrium coupling.

    PubMed

    Hoffmann, Eufrozina A; Nagypal, Istvan

    2006-06-01

    It is pointed out and illustrated in the present paper that if a homogeneous multiple equilibrium system containing k components and q species is composed of the reactants actually taken and their reactions contain only k + 1 species, then we have a unique representation with (q - k) stoichiometrically independent reactions (SIRs). We define these as coupling reactions. All the other possible combinations with k + 1 species are the coupled reactions that are in equilibrium when the (q - k) SIRs are in equilibrium. The response of the equilibrium state for perturbation is determined by the coupling and coupled equilibria. Depending on the circumstances and the actual thermodynamic data, the effect of coupled equilibria may overtake the effect of the coupling ones, leading to phenomena that are in apparent contradiction with Le Chatelier's principle. PMID:16722770

  10. Three tooth kinematic coupling

    SciTech Connect

    Hale, L.C.

    2000-05-23

    A three tooth kinematic coupling is disclosed based on having three theoretical line contacts formed by mating teeth rather than six theoretical point contacts. The geometry requires one coupling half to have curved teeth and the other coupling half to have flat teeth. Each coupling half has a relieved center portion which does not effect the kinematics, but in the limit as the face width approaches zero, three line contacts become six point contacts. As a result of having line contact, a three tooth coupling has greater load capacity and stiffness. The kinematic coupling has application for use in precision fixturing for tools or workpieces, and as a registration device for a work or tool changer or for optics in various products.

  11. Three tooth kinematic coupling

    SciTech Connect

    Hale, Layton C.

    2000-01-01

    A three tooth kinematic coupling based on having three theoretical line contacts formed by mating teeth rather than six theoretical point contacts. The geometry requires one coupling half to have curved teeth and the other coupling half to have flat teeth. Each coupling half has a relieved center portion which does not effect the kinematics, but in the limit as the face width approaches zero, three line contacts become six point contacts. As a result of having line contact, a three tooth coupling has greater load capacity and stiffness. The kinematic coupling has application for use in precision fixturing for tools or workpieces, and as a registration device for a work or tool changer or for optics in various products.

  12. Diagnostic instruments for behavioural addiction: an overview

    PubMed Central

    Albrecht, Ulrike; Kirschner, Nina Ellen; Grüsser, Sabine M.

    2007-01-01

    In non-substance-related addiction, the so-called behavioural addiction, no external psychotropic substances are consumed. The psychotropic effect consists of the body’s own biochemical processes induced only by excessive activities. Until recently, knowledge was limited with respect to clinically relevant excessive reward-seeking behaviour, such as pathological gambling, excessive shopping and working which meet diagnostic criteria of dependent behaviour. To date, there is no consistent concept for diagnosis and treatment of excessive reward-seeking behaviour, and its classification is uncertain. Therefore, a clear conceptualization of the so-called behavioural addictions is of great importance. The use of adequate diagnostic instruments is necessary for successful therapeutical implications. This article provides an overview of the current popular diagnostic instruments assessing the different forms of behavioural addiction. Especially in certain areas there are only few valid and reliable instruments available to assess excessive rewarding behaviours that fulfill the criteria of addiction. PMID:19742294

  13. Mouse behavioural analysis in systems biology

    PubMed Central

    van Meer, Peter; Raber, Jacob

    2005-01-01

    Molecular techniques allowing in vivo modulation of gene expression have provided unique opportunities and challenges for behavioural studies aimed at understanding the function of particular genes or biological systems under physiological or pathological conditions. Although various animal models are available, the laboratory mouse (Mus musculus) has unique features and is therefore a preferred animal model. The mouse shares a remarkable genetic resemblance and aspects of behaviour with humans. In this review, first we describe common mouse models for behavioural analyses. As both genetic and environmental factors influence behavioural performance and need to be carefully evaluated in behavioural experiments, considerations for designing and interpretations of these experiments are subsequently discussed. Finally, common behavioural tests used to assess brain function are reviewed, and it is illustrated how behavioural tests are used to increase our understanding of the role of histaminergic neurotransmission in brain function. PMID:16035954

  14. Predicting behaviour from perceived behavioural control: tests of the accuracy assumption of the theory of planned behaviour.

    PubMed

    Sheeran, Paschal; Trafimow, David; Armitage, Christopher J

    2003-09-01

    The theory of planned behaviour assumes that the accuracy of perceived behavioural control (PBC) determines the strength of the PBC-behaviour relationship. However, this assumption has never been formally tested. The present research developed and validated a proxy measure of actual control (PMAC) in order to test the assumption. In two studies, participants completed measures of intention and PBC, and subsequently completed measures of behaviour and the PMAC. Validity of the PMAC was established by findings showing; (a). that the PMAC moderated the intention-behaviour relation, and (b). that PMAC scores did not reflect attributions for participants' failure to enact their stated intentions. Accuracy was operationalized as the difference between PBC and PMAC scores. Consistent with theoretical expectations, several analyses indicated that greater accuracy of PBC was associated with improved prediction of behaviour by PBC. PMID:14567844

  15. Strong Coupling Continuum QCD

    SciTech Connect

    Michael Pennington

    2011-05-01

    The Schwinger-Dyson, Bethe-Salpeter system of equations are the link between coloured quarks and gluons, and colourless hadrons and their properties. This talk reviews some aspects of these studies from the infrared behaviour of ghosts to the prediction of electromagnetic form-factors.

  16. Strong Coupling Continuum QCD

    SciTech Connect

    Pennington, M. R.

    2011-05-23

    The Schwinger-Dyson, Bethe-Salpeter system of equations are the link between coloured quarks and gluons, and colourless hadrons and their properties. This talk reviews some aspects of these studies from the infrared behaviour of ghosts to the prediction of electromagnetic form-factors.

  17. Translation-coupling systems

    DOEpatents

    Pfleger, Brian; Mendez-Perez, Daniel

    2013-11-05

    Disclosed are systems and methods for coupling translation of a target gene to a detectable response gene. A version of the invention includes a translation-coupling cassette. The translation-coupling cassette includes a target gene, a response gene, a response-gene translation control element, and a secondary structure-forming sequence that reversibly forms a secondary structure masking the response-gene translation control element. Masking of the response-gene translation control element inhibits translation of the response gene. Full translation of the target gene results in unfolding of the secondary structure and consequent translation of the response gene. Translation of the target gene is determined by detecting presence of the response-gene protein product. The invention further includes RNA transcripts of the translation-coupling cassettes, vectors comprising the translation-coupling cassettes, hosts comprising the translation-coupling cassettes, methods of using the translation-coupling cassettes, and gene products produced with the translation-coupling cassettes.

  18. Translation-coupling systems

    DOEpatents

    Pfleger, Brian; Mendez-Perez, Daniel

    2015-05-19

    Disclosed are systems and methods for coupling translation of a target gene to a detectable response gene. A version of the invention includes a translation-coupling cassette. The translation-coupling cassette includes a target gene, a response gene, a response-gene translation control element, and a secondary structure-forming sequence that reversibly forms a secondary structure masking the response-gene translation control element. Masking of the response-gene translation control element inhibits translation of the response gene. Full translation of the target gene results in unfolding of the secondary structure and consequent translation of the response gene. Translation of the target gene is determined by detecting presence of the response-gene protein product. The invention further includes RNA transcripts of the translation-coupling cassettes, vectors comprising the translation-coupling cassettes, hosts comprising the translation-coupling cassettes, methods of using the translation-coupling cassettes, and gene products produced with the translation-coupling cassettes.

  19. Gear Spline Coupling Program

    SciTech Connect

    Guo, Yi; Errichello, Robert

    2013-08-29

    An analytical model is developed to evaluate the design of a spline coupling. For a given torque and shaft misalignment, the model calculates the number of teeth in contact, tooth loads, stiffnesses, stresses, and safety factors. The analytic model provides essential spline coupling design and modeling information and could be easily integrated into gearbox design and simulation tools.

  20. Social behaviour in mesopelagic jellyfish

    PubMed Central

    Kaartvedt, Stein; Ugland, Karl I.; Klevjer, Thor A.; Røstad, Anders; Titelman, Josefin; Solberg, Ingrid

    2015-01-01

    Gelatinous organisms apparently play a central role in deep pelagic ecosystems, but lack of observational methodologies has restricted information on their behaviour. We made acoustic records of diel migrating jellyfish Periphylla periphylla forming small, ephemeral groups at the upper fringe of an acoustic scattering layer consisting of krill. Groups of P. periphylla were also documented photographically using a remotely operated vehicle (ROV). Although the adaptive value of group formation remains speculative, we clearly demonstrate the ability of these jellyfishes to locate and team up with each other. PMID:26065904

  1. Social behaviour in mesopelagic jellyfish.

    PubMed

    Kaartvedt, Stein; Ugland, Karl I; Klevjer, Thor A; Røstad, Anders; Titelman, Josefin; Solberg, Ingrid

    2015-06-11

    Gelatinous organisms apparently play a central role in deep pelagic ecosystems, but lack of observational methodologies has restricted information on their behaviour. We made acoustic records of diel migrating jellyfish Periphylla periphylla forming small, ephemeral groups at the upper fringe of an acoustic scattering layer consisting of krill. Groups of P. periphylla were also documented photographically using a remotely operated vehicle (ROV). Although the adaptive value of group formation remains speculative, we clearly demonstrate the ability of these jellyfishes to locate and team up with each other.

  2. Social behaviour in mesopelagic jellyfish.

    PubMed

    Kaartvedt, Stein; Ugland, Karl I; Klevjer, Thor A; Røstad, Anders; Titelman, Josefin; Solberg, Ingrid

    2015-01-01

    Gelatinous organisms apparently play a central role in deep pelagic ecosystems, but lack of observational methodologies has restricted information on their behaviour. We made acoustic records of diel migrating jellyfish Periphylla periphylla forming small, ephemeral groups at the upper fringe of an acoustic scattering layer consisting of krill. Groups of P. periphylla were also documented photographically using a remotely operated vehicle (ROV). Although the adaptive value of group formation remains speculative, we clearly demonstrate the ability of these jellyfishes to locate and team up with each other. PMID:26065904

  3. Water behaviour in nanoporous aluminosilicates.

    PubMed

    Smirnov, Konstantin S; Bougeard, Daniel

    2010-07-21

    This paper briefly reviews results of molecular dynamics simulation studies of water confined in nanoporous aluminosilicates. The behaviour of confined molecules is shown to be influenced by the nature of the host structure, and the size and the topology of the voids. For some of the systems discussed the ambiguity in results of different modelling studies call for the use of extended potential and structural models. Thus, the use of polarizable force fields was shown to be necessary to take into account the variation of the molecular dipole of confined molecules in different environments. PMID:21399287

  4. Social behaviour in mesopelagic jellyfish

    NASA Astrophysics Data System (ADS)

    Kaartvedt, Stein; Ugland, Karl I.; Klevjer, Thor A.; Røstad, Anders; Titelman, Josefin; Solberg, Ingrid

    2015-06-01

    Gelatinous organisms apparently play a central role in deep pelagic ecosystems, but lack of observational methodologies has restricted information on their behaviour. We made acoustic records of diel migrating jellyfish Periphylla periphylla forming small, ephemeral groups at the upper fringe of an acoustic scattering layer consisting of krill. Groups of P. periphylla were also documented photographically using a remotely operated vehicle (ROV). Although the adaptive value of group formation remains speculative, we clearly demonstrate the ability of these jellyfishes to locate and team up with each other.

  5. Water behaviour in nanoporous aluminosilicates.

    PubMed

    Smirnov, Konstantin S; Bougeard, Daniel

    2010-07-21

    This paper briefly reviews results of molecular dynamics simulation studies of water confined in nanoporous aluminosilicates. The behaviour of confined molecules is shown to be influenced by the nature of the host structure, and the size and the topology of the voids. For some of the systems discussed the ambiguity in results of different modelling studies call for the use of extended potential and structural models. Thus, the use of polarizable force fields was shown to be necessary to take into account the variation of the molecular dipole of confined molecules in different environments.

  6. Chimera and phase-cluster states in populations of coupled chemical oscillators

    NASA Astrophysics Data System (ADS)

    Tinsley, Mark R.; Nkomo, Simbarashe; Showalter, Kenneth

    2012-09-01

    Populations of coupled oscillators may exhibit two coexisting subpopulations, one with synchronized oscillations and the other with unsynchronized oscillations, even though all of the oscillators are coupled to each other in an equivalent manner. This phenomenon, discovered about ten years ago in theoretical studies, was then further characterized and named the chimera state after the Greek mythological creature made up of different animals. The highly counterintuitive coexistence of coherent and incoherent oscillations in populations of identical oscillators, each with an equivalent coupling structure, inspired great interest and a flurry of theoretical activity. Here we report on experimental studies of chimera states and their relation to other synchronization states in populations of coupled chemical oscillators. Our experiments with coupled Belousov-Zhabotinsky oscillators and corresponding simulations reveal chimera behaviour that differs significantly from the behaviour found in theoretical studies of phase-oscillator models.

  7. Couple dissatisfaction and eating profile: a mediation effect of coping style.

    PubMed

    Gagnon-Girouard, M-P; Gagnon, C; Bégin, C; Provencher, V; Tremblay, A; Boivin, S; Lemieux, S

    2010-12-01

    Individuals' ways of coping with psychological stress have often been associated with body weight regulation through their impact on eating behaviours. In particular, emotion-oriented and distraction-oriented coping styles have been steadily related to disordered eating. Couple dissatisfaction may be experienced as an important psychological stressor and could therefore affect eating behaviours through the use of inadequate coping strategies. The study proposes 1) to compare women reporting a low vs a high level of couple satisfaction, and 2) to test mediational models including couple satisfaction, coping styles, and eating variables. Analyses were performed among 65 overweight/obese premenopausal women who reported being weight-preoccupied. Women exhibiting couple dissatisfaction (34.8%) showed a higher level of EDE-Q restraint, more intense concerns about eating and shape, a higher level of disinhibition and susceptibility to hunger and endorsed more often a distraction-oriented coping style, independently of their body weight. Furthermore, distraction- oriented coping style seemed to be a valid mediator of the relation between couple dissatisfaction and eating behaviours. Since non-normative eating behaviours, namely disinhibition and susceptibility to hunger, have been particularly linked to a higher body weight status, it is relevant to extend the scope of interest to more distal contributing factors, such as couple dissatisfaction.

  8. Is a convergently derived muscle-activity pattern driving novel raking behaviours in teleost fishes?

    PubMed

    Konow, Nicolai; Sanford, Christopher P J

    2008-03-01

    Behavioural differences across prey-capture and processing mechanisms may be governed by coupled or uncoupled feeding systems. Osteoglossomorph and salmonid fishes process prey in a convergently evolved tongue-bite apparatus (TBA), which is musculoskeletally coupled with the primary oral jaws. Altered muscle-activity patterns (MAPs) in these coupled jaw systems could be associated with the independent origin of a novel raking behaviour in these unrelated lineages. Substantial MAP changes in the evolution of novel behaviours have rarely been quantified so we examined MAP differences across strikes, chewing and rakes in a derived raking salmonid, the rainbow trout, Oncorhynchus mykiss. Electromyography, including activity onset timing, duration, mean amplitude and integrated area from five feeding muscles revealed significant differences between behaviour-specific MAPs. Specifically, early activity onset in the protractor hyoideus and adductor mandibularis muscles characterised raking, congruent with a recent biomechanical model of the component-mechanisms driving the raking preparatory and power-stroke phases. Oncorhynchus raking MAPs were then compared with a phylogenetically derived osteoglossomorph representative, the Australian arowana, Scleropages jardinii. In both taxa, early onset of protractor hyoideus and adductor mandibularis activity characterised the raking preparatory phase, indicating a convergently derived MAP, while more subtle inter-lineage divergence in raking MAPs resulted from onset-timing and duration differences in sternohyoideus and hypaxialis activity. Convergent TBA morphologies are thus powered by convergently derived MAPs, a phenomenon not previously demonstrated in feeding mechanisms. Between lineages, differences in TBA morphology and associated differences in the functional coupling of jaw systems appear to be important factors in shaping the diversification of raking behaviours. PMID:18310124

  9. Neural architecture of choice behaviour in a concurrent interval schedule.

    PubMed

    Kalenscher, Tobias; Diekamp, Bettina; Güntürkün, Onur

    2003-11-01

    Concurrent interval schedules are classic experimental paradigms that are traditionally employed in psychological research on choice behaviour. To analyse the neural basis of choice in a concurrent fixed interval schedule, pigeons were trained to peck on two response keys. Responses were differentially rewarded in key specific short or long time intervals (SI vs. LI). Using tetrodotoxin, we reversibly blocked the neostriatum caudolaterale (NCL, the avian functional equivalent of the prefrontal cortex), avian caudate-putamen and nucleus accumbens to examine their contribution. A detailed analysis of baseline choice behaviour revealed that response distribution and key affinity were determined by cued or time-related expectancy for rewards on the SI key. The pigeons' response frequency increased on the SI key and decreased on the LI key with increasing temporal proximity to the SI reward and pigeons switched to the LI key after reward delivery. Pecking bursts on the LI key were negatively correlated with bursts on the SI key. Neostriatum caudolaterale inactivation did not affect pecking activity per se but interfered with reward-related temporal modulation of pecking frequency, switching pattern and coupling of LI to SI pecks. Blockade of caudate-putamen resulted in a complete behavioural halt, while inactivation of nucleus accumbens diminished operant behaviour without affecting consummatory responses. These data suggest that the NCL is tuned via indirect striato-pallial projections to integrate cued or time-related reward expectancy into a response selection process in order to set, maintain or shift goals. The NCL possibly feeds forward the resulting motor commands to the caudate-putamen for execution.

  10. Effects of couples' characteristics on contraceptive use in sub-Saharan Africa: the Ghanaian example.

    PubMed

    Oheneba-Sakyi, Y; Takyi, B K

    1997-01-01

    Using data from the 1988 Ghana Demographic and Health Survey, this study examines couples' demographic and socioeconomic characteristics in the context of their attitudes towards family planning, and the impact of these factors on the use of contraceptives. The characteristics of the husbands and their influence on wives' behaviour illustrate the role of intra-household relations between men and women and their effect on fertility-related behaviour in patriarchal African societies.

  11. Effects of couples' characteristics on contraceptive use in sub-Saharan Africa: the Ghanaian example.

    PubMed

    Oheneba-Sakyi, Y; Takyi, B K

    1997-01-01

    Using data from the 1988 Ghana Demographic and Health Survey, this study examines couples' demographic and socioeconomic characteristics in the context of their attitudes towards family planning, and the impact of these factors on the use of contraceptives. The characteristics of the husbands and their influence on wives' behaviour illustrate the role of intra-household relations between men and women and their effect on fertility-related behaviour in patriarchal African societies. PMID:9881118

  12. The pedestrian behaviour of Spanish adolescents.

    PubMed

    Sullman, M J M; Gras, M E; Font-Mayolas, S; Masferrer, L; Cunill, M; Planes, M

    2011-06-01

    Adolescent pedestrians are a particularly vulnerable group of road users. This research tested the applicability of the recently developed Adolescent Road user Behaviour Questionnaire (ARBQ) amongst a sample of 2006 Spanish adolescents. Confirmatory Factor Analysis of the full scale found that the original three factors did not adequately fit the data, but an acceptable fit was obtained for the shortened 21-item version of the scale. In line with research from the UK, the present study found that males reported more unsafe road crossing behaviour and playing on the roads, but there was no gender difference for engaging in planned protective behaviour. This research also confirmed that unsafe road crossing behaviour increased with age, while dangerous playing on the road and planned protective behaviours both decreased with age. The present study also confirmed that the ARBQ is a useful tool for investigating the safety-related behaviour of adolescents on the road.

  13. Viscoelastic behaviour of pumpkin balloons

    NASA Astrophysics Data System (ADS)

    Gerngross, T.; Xu, Y.; Pellegrino, S.

    2008-11-01

    The lobes of the NASA ULDB pumpkin-shaped super-pressure balloons are made of a thin polymeric film that shows considerable time-dependent behaviour. A nonlinear viscoelastic model based on experimental measurements has been recently established for this film. This paper presents a simulation of the viscoelastic behaviour of ULDB balloons with the finite element software ABAQUS. First, the standard viscoelastic modelling capabilities available in ABAQUS are examined, but are found of limited accuracy even for the case of simple uniaxial creep tests on ULDB films. Then, a nonlinear viscoelastic constitutive model is implemented by means of a user-defined subroutine. This approach is verified by means of biaxial creep experiments on pressurized cylinders and is found to be accurate provided that the film anisotropy is also included in the model. A preliminary set of predictions for a single lobe of a ULDB is presented at the end of the paper. It indicates that time-dependent effects in a balloon structure can lead to significant stress redistribution and large increases in the transverse strains in the lobes.

  14. Synchronization of weakly nonlinear oscillators with Huygens' coupling.

    PubMed

    Ramirez, J Pena; Fey, Rob H B; Nijmeijer, H

    2013-09-01

    In this paper, the occurrence of synchronization in pairs of weakly nonlinear self-sustained oscillators that interact via Huygens' coupling, i.e., a suspended rigid bar, is treated. In the analysis, a generalized version of the classical Huygens' experiment of synchronization of two coupled pendulum clocks is considered, in which the clocks are replaced by arbitrary self-sustained oscillators. Sufficient conditions for the existence and stability of synchronous solutions in the coupled system are derived by using the Poincaré method. The obtained results are supported by computer simulations and experiments conducted on a dedicated experimental platform. It is demonstrated that the mass of the coupling bar is an important parameter with respect to the limit synchronous behaviour in the oscillators.

  15. A scanning transmon qubit for strong coupling circuit quantum electrodynamics.

    PubMed

    Shanks, W E; Underwood, D L; Houck, A A

    2013-01-01

    Like a quantum computer designed for a particular class of problems, a quantum simulator enables quantitative modelling of quantum systems that is computationally intractable with a classical computer. Superconducting circuits have recently been investigated as an alternative system in which microwave photons confined to a lattice of coupled resonators act as the particles under study, with qubits coupled to the resonators producing effective photon-photon interactions. Such a system promises insight into the non-equilibrium physics of interacting bosons, but new tools are needed to understand this complex behaviour. Here we demonstrate the operation of a scanning transmon qubit and propose its use as a local probe of photon number within a superconducting resonator lattice. We map the coupling strength of the qubit to a resonator on a separate chip and show that the system reaches the strong coupling regime over a wide scanning area.

  16. Ubiquitous electron-plasmon coupling in doped semiconductors

    NASA Astrophysics Data System (ADS)

    Caruso, Fabio; Giustino, Feliciano

    The interplay between electrons and bosonic excitations [as, e.g., phonons, collective charge-density fluctuations (plasmons), and magnons] is pervasive in matter and underlies an extremely broad spectrum of physical phenomena, as, for instance, current dissipation, superconductivity, hot-carrier thermalisation, and band structure replicas. At variance with phonons, however, questions pertaining the strength of electron-plasmon coupling in solids are still awaiting further investigations. We developed and implemented a first-principles theory of electron-plasmon coupling based on many-body perturbation theory. Our first-principles calculations reveal that electron-plasmon coupling alters ubiquitously the dynamical and optical properties of semiconductors at high doping concentrations. This behaviour stems from the emergence of low-energy extrinsic plasmons which may couple electronic states in the vicinity of the Fermi energy

  17. The contribution of behavioural science to primary care research: development and evaluation of behaviour change interventions.

    PubMed

    Sutton, Stephen

    2011-10-01

    Behavioural science is concerned with predicting, explaining and changing behaviour. Taking a personal perspective, this article aims to show how behavioural science can contribute to primary care research, specifically in relation to the development and evaluation of interventions to change behaviour. After discussing the definition and measurement of behaviour, the principle of compatibility and theories of behaviour change, the article outlines two examples of behaviour change trials (one on medication adherence and the other on physical activity), which were part of a research programme on prevention of chronic disease and its consequences. The examples demonstrate how, in a multidisciplinary context, behavioural science can contribute to primary care research in several important ways, including posing relevant research questions, defining the target behaviour, understanding the psychological determinants of behaviour, developing behaviour change interventions and selection or development of measures. The article concludes with a number of recommendations: (i) whether the aim is prediction, explanation or change, defining the target behaviour is a crucial first step; (ii) interventions should be explicitly based on theories that specify the factors that need to be changed in order to produce the desired change in behaviour; (iii) intervention developers need to be aware of the differences between different theories and select a theory only after careful consideration of the alternatives assessed against relevant criteria; and (iv) developers need to be aware that interventions can never be entirely theory based. PMID:22284944

  18. Theoretical explanations for maintenance of behaviour change: a systematic review of behaviour theories

    PubMed Central

    Kwasnicka, Dominika; Dombrowski, Stephan U; White, Martin; Sniehotta, Falko

    2016-01-01

    ABSTRACT Background: Behaviour change interventions are effective in supporting individuals in achieving temporary behaviour change. Behaviour change maintenance, however, is rarely attained. The aim of this review was to identify and synthesise current theoretical explanations for behaviour change maintenance to inform future research and practice. Methods: Potentially relevant theories were identified through systematic searches of electronic databases (Ovid MEDLINE, Embase, PsycINFO). In addition, an existing database of 80 theories was searched, and 25 theory experts were consulted. Theories were included if they formulated hypotheses about behaviour change maintenance. Included theories were synthesised thematically to ascertain overarching explanations for behaviour change maintenance. Initial theoretical themes were cross-validated. Findings: One hundred and seventeen behaviour theories were identified, of which 100 met the inclusion criteria. Five overarching, interconnected themes representing theoretical explanations for behaviour change maintenance emerged. Theoretical explanations of behaviour change maintenance focus on the differential nature and role of motives, self-regulation, resources (psychological and physical), habits, and environmental and social influences from initiation to maintenance. Discussion: There are distinct patterns of theoretical explanations for behaviour change and for behaviour change maintenance. The findings from this review can guide the development and evaluation of interventions promoting maintenance of health behaviours and help in the development of an integrated theory of behaviour change maintenance. PMID:26854092

  19. Model development for household waste prevention behaviour

    SciTech Connect

    Bortoleto, Ana Paula; Kurisu, Kiyo H.; Hanaki, Keisuke

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer We model waste prevention behaviour using structure equation modelling. Black-Right-Pointing-Pointer We merge attitude-behaviour theories with wider models from environmental psychology. Black-Right-Pointing-Pointer Personal norms and perceived behaviour control are the main behaviour predictors. Black-Right-Pointing-Pointer Environmental concern, moral obligation and inconvenience are the main influence on the behaviour. Black-Right-Pointing-Pointer Waste prevention and recycling are different dimensions of waste management behaviour. - Abstract: Understanding waste prevention behaviour (WPB) could enable local governments and decision makers to design more-effective policies for reducing the amount of waste that is generated. By merging well-known attitude-behaviour theories with elements from wider models from environmental psychology, an extensive cognitive framework that provides new and valuable insights is developed for understanding the involvement of individuals in waste prevention. The results confirm the usefulness of the theory of planned behaviour and of Schwartz's altruistic behaviour model as bases for modelling participation in waste prevention. A more elaborate integrated model of prevention was shown to be necessary for the complete analysis of attitudinal aspects associated with waste prevention. A postal survey of 158 respondents provided empirical support for eight of 12 hypotheses. The proposed structural equation indicates that personal norms and perceived behaviour control are the main predictors and that, unlike the case of recycling, subjective norms have a weak influence on WPB. It also suggests that, since social norms have not presented a direct influence, WPB is likely to be influenced by a concern for the environment and the community as well by perceptions of moral obligation and inconvenience. Results also proved that recycling and waste prevention represent different dimensions of waste

  20. Interpersonal behaviour in relation to burnout.

    PubMed

    Geuens, Nina; Leemans, Annemie; Bogaerts, Annick; Van Bogaert, Peter; Franck, Erik

    2015-12-01

    Organisational and work-related challenges faced by midwives make them vulnerable to burnout, but individual factors, such as interpersonal behaviour, can also contribute. A study in eight hospitals in the Dutch-speaking part of Belgium investigated the prevalence of burnout among Flemish midwives, assessed their interpersonal behaviour, and explored the relationship between interpersonal behaviour, burnout, job satisfaction and intention to leave. This article describes the study and reports the findings. PMID:26602486

  1. Depression: The Differing Narratives of Couples in Couple Therapy

    ERIC Educational Resources Information Center

    Rautiainen, Eija-Liisa; Aaltonen, Jukka

    2010-01-01

    How does the spouse of a person with depression take part in constructing narratives of depression in couple therapy? In this study we examined couples' ways of co-constructing narratives of depression in couple therapy. Three couple therapy processes were chosen for the study, one spouse in each couple having been referred to an outpatient clinic…

  2. Further understanding of Huygens’ coupled clocks: The effect of stiffness

    NASA Astrophysics Data System (ADS)

    Peña Ramirez, J.; Aihara, K.; Fey, R. H. B.; Nijmeijer, H.

    2014-03-01

    A simplified model of the classical Huygens’ experiment on synchronization of pendulum clocks is examined. The model consists of two pendula coupled by an elastically supported rigid bar. The synchronized limit behaviour of the system, i.e. in-phase and anti-phase synchronization of the pendula, is studied as a function of the stiffness of the spring that supports the coupling bar. It is demonstrated that the stiffness has a large influence on the existence, stability, and oscillation frequency of the in-phase solution. The relationship between the obtained results and experimental results that have been reported in the literature, including Huygens’ original observations, is stressed.

  3. Plant adaptive behaviour in hydrological models (Invited)

    NASA Astrophysics Data System (ADS)

    van der Ploeg, M. J.; Teuling, R.

    2013-12-01

    Models that will be able to cope with future precipitation and evaporation regimes need a solid base that describes the essence of the processes involved [1]. Micro-behaviour in the soil-vegetation-atmosphere system may have a large impact on patterns emerging at larger scales. A complicating factor in the micro-behaviour is the constant interaction between vegetation and geology in which water plays a key role. The resilience of the coupled vegetation-soil system critically depends on its sensitivity to environmental changes. As a result of environmental changes vegetation may wither and die, but such environmental changes may also trigger gene adaptation. Constant exposure to environmental stresses, biotic or abiotic, influences plant physiology, gene adaptations, and flexibility in gene adaptation [2-6]. Gene expression as a result of different environmental conditions may profoundly impact drought responses across the same plant species. Differences in response to an environmental stress, has consequences for the way species are currently being treated in models (single plant to global scale). In particular, model parameters that control root water uptake and plant transpiration are generally assumed to be a property of the plant functional type. Assigning plant functional types does not allow for local plant adaptation to be reflected in the model parameters, nor does it allow for correlations that might exist between root parameters and soil type. Models potentially provide a means to link root water uptake and transport to large scale processes (e.g. Rosnay and Polcher 1998, Feddes et al. 2001, Jung 2010), especially when powered with an integrated hydrological, ecological and physiological base. We explore the experimental evidence from natural vegetation to formulate possible alternative modeling concepts. [1] Seibert, J. 2000. Multi-criteria calibration of a conceptual runoff model using a genetic algorithm. Hydrology and Earth System Sciences 4(2): 215

  4. A picture for the coupling of unemployment and inflation

    NASA Astrophysics Data System (ADS)

    Safdari, H.; Hosseiny, A.; Vasheghani Farahani, S.; Jafari, G. R.

    2016-02-01

    The aim of this article is to illustrate the scaling features of two well heard characters in the media; unemployment and inflation. We carry out a scaling analysis on the coupling between unemployment and inflation. This work is based on the wavelet analysis as well as the detrended fluctuation analysis (DFA). Through our analysis we state that while unemployment is time scale invariant, inflation is bi-scale. We show that inflation possess a five year time scale where it experiences different behaviours before and after this scale period. This behaviour of inflation provides basis for the coupling to inherit the stated time interval. Although inflation is bi-scale, it is unemployment that shows a strong multifractality feature. Owing to the cross wavelet analysis we provide a picture that illustrates the dynamics of coupling between unemployment and inflation regarding intensity, direction, and scale. The fact of the matter is that the coupling between inflation and unemployment is not equal in one way compared to the opposite. Regarding the scaling; coupling exhibits different features in various scales. In a sense that although in one scale its correlation behaves in a positive/negative manner, at the same time it can be negative/positive for another scale.

  5. Managing agitated behaviour in older people.

    PubMed

    King, Camille

    2012-09-01

    Older people diagnosed with dementia can have complex needs, especially when they exhibit agitated behaviour. Patients with agitated behaviour challenge the delivery of health care. Often the behaviour is a symptom of unmet needs in this population (Dewing 2010). It is important for nurses to understand the underlying causes and apply evidence-based interventions in their nursing practice to promote health, safety and the highest quality of life possible. This article defines and classifies agitated behaviours, discusses implications for their management and then presents evidence-based interventions nurses can use. The interventions are categorised according to each of the five senses.

  6. Translating teamwork behaviours from aviation to healthcare: development of behavioural markers for neonatal resuscitation

    PubMed Central

    Thomas, E; Sexton, J; Helmreich, R

    2004-01-01

    Improving teamwork in healthcare may help reduce and manage errors. This paper takes a step toward that goal by (1) proposing a set of teamwork behaviours, or behavioural markers, for neonatal resuscitation; (2) presenting a data form for recording observations about these markers; and (3) comparing and contrasting different sets of teamwork behaviours that have been developed for healthcare. Data from focus groups of neonatal providers, surveys, and video recordings of neonatal resuscitations were used to identify some new teamwork behaviours, to translate existing aviation team behaviours to this setting, and to develop a data collection form. This behavioural marker audit form for neonatal resuscitation lists and defines 10 markers that describe specific, observable behaviours seen during the resuscitation of newborn infants. These markers are compared with those developed by other groups. Future research should determine the relations among these behaviours and errors, and test their usefulness in measuring the impact of team training interventions. PMID:15465957

  7. Mirroring and beyond: coupled dynamics as a generalized framework for modelling social interactions

    PubMed Central

    Hasson, Uri; Frith, Chris D.

    2016-01-01

    When people observe one another, behavioural alignment can be detected at many levels, from the physical to the mental. Likewise, when people process the same highly complex stimulus sequences, such as films and stories, alignment is detected in the elicited brain activity. In early sensory areas, shared neural patterns are coupled to the low-level properties of the stimulus (shape, motion, volume, etc.), while in high-order brain areas, shared neural patterns are coupled to high-levels aspects of the stimulus, such as meaning. Successful social interactions require such alignments (both behavioural and neural), as communication cannot occur without shared understanding. However, we need to go beyond simple, symmetric (mirror) alignment once we start interacting. Interactions are dynamic processes, which involve continuous mutual adaptation, development of complementary behaviour and division of labour such as leader–follower roles. Here, we argue that interacting individuals are dynamically coupled rather than simply aligned. This broader framework for understanding interactions can encompass both processes by which behaviour and brain activity mirror each other (neural alignment), and situations in which behaviour and brain activity in one participant are coupled (but not mirrored) to the dynamics in the other participant. To apply these more sophisticated accounts of social interactions to the study of the underlying neural processes we need to develop new experimental paradigms and novel methods of data analysis PMID:27069044

  8. Mirroring and beyond: coupled dynamics as a generalized framework for modelling social interactions.

    PubMed

    Hasson, Uri; Frith, Chris D

    2016-05-01

    When people observe one another, behavioural alignment can be detected at many levels, from the physical to the mental. Likewise, when people process the same highly complex stimulus sequences, such as films and stories, alignment is detected in the elicited brain activity. In early sensory areas, shared neural patterns are coupled to the low-level properties of the stimulus (shape, motion, volume, etc.), while in high-order brain areas, shared neural patterns are coupled to high-levels aspects of the stimulus, such as meaning. Successful social interactions require such alignments (both behavioural and neural), as communication cannot occur without shared understanding. However, we need to go beyond simple, symmetric (mirror) alignment once we start interacting. Interactions are dynamic processes, which involve continuous mutual adaptation, development of complementary behaviour and division of labour such as leader-follower roles. Here, we argue that interacting individuals are dynamically coupled rather than simply aligned. This broader framework for understanding interactions can encompass both processes by which behaviour and brain activity mirror each other (neural alignment), and situations in which behaviour and brain activity in one participant are coupled (but not mirrored) to the dynamics in the other participant. To apply these more sophisticated accounts of social interactions to the study of the underlying neural processes we need to develop new experimental paradigms and novel methods of data analysis. PMID:27069044

  9. Interfacial behaviours of smart composites

    NASA Astrophysics Data System (ADS)

    Poon, Chi-Kin

    The success of conventional fiber reinforced composites (FRC) relies on the quality of bonding between fibers and matrix. A review of literatures shows that there is a lack of theoretical models and experimental findings on the interfacial behaviours of the SMA-composites. In the past, the operation limit as well as the ideal actuation condition of SMA inclusions could not be predicted accurately during the design stage and the SMA-composite structures may therefore suffer a potential risk of sudden failure due to overloading or over-actuation. The theoretical models developed in this research provide a study basis for the prediction of internal stresses and interfacial strength of the SMA-composites. Martensite volume fraction is considered as a critical parameter which determines the material properties and shape memory effect (SME) of the SMA inclusions. The proposed model reproduce the SMA behaviour inside a substrate, evolutions of martensite volume fraction and elastic modulus of SMA, and the internal stresses along the embedded length in different loading and actuation scenarios. The concepts of 'constant martensite volume fraction region (CMR)' and 'constant axial stress region (CASR)' are proposed to justify the desired SMA actuation. In addition, substantial improvement of the initial debond stress is predicted with the increase of the actuation temperature. The 'Optimum Actuation Condition (OAC)' that ensures the reinforcement of SMA composite but avoids the failure of composite interface due to over-actuation is also defined to optimize the application of SME in the composite structure within a safety actuation limit. A simplified OAC (SOAC) is also developed to provide an analytical solution of OAC and thus the ideal actuation temperature for achieving such specific actuation condition can be estimated more easily. Single fiber pullout test and finite element analysis (FEA) are employed to evaluate the interfacial behaviours and analyze the stress

  10. Coupling in the Tevatron

    SciTech Connect

    Gelfand, N.M.

    1994-12-01

    The performance of the Fermilab Tevatron Collider at the commencement of run Ib was far below expectations. After a frustrating period of several months, a low-{beta} quad downstream of the interaction point at B0 was found to be rolled. This rolled quadrupole coupled the horizontal and vertical motion of the Tevatron beams. It also made matching the beam from the Main Ring to the Tevatron impossible, resulting in emittance blow up on injection. The net result of the roll was a significant reduction in the Tevatron luminosity. When the roll in the quadrupole was corrected the performance of the Tevatron improved dramatically. This note will discuss the experimental data indicating the presence of coupling and subsequent calculations which show how coupling an affect the luminosity. It is not intended to exhaust a discussion of coupling, which hopefully will be understood well enough to be discussed in a subsequent note.

  11. Disformally coupled inflation

    NASA Astrophysics Data System (ADS)

    van de Bruck, Carsten; Koivisto, Tomi; Longden, Chris

    2016-03-01

    A disformal coupling between two scalar fields is considered in the context of cosmological inflation. The coupling introduces novel derivative interactions mixing the kinetic terms of the fields but without introducing superluminal or unstable propagation of the two scalar fluctuation modes. Though the typical effect of the disformal coupling is to inhibit one of the fields from inflating the universe, the energy density of the other field can drive viable near Sitter -inflation in the presence of nontrivial disformal dynamics, in particular when one assumes exponential instead of power-law form for the couplings. The linear perturbation equations are written for the two-field system, its canonical degrees of freedom are quantised, their spectra are derived and the inflationary predictions are reported for numerically solved exponential models. A generic prediction is low tensor-to-scalar ratio.

  12. [Main Cellular Redox Couples].

    PubMed

    Bilan, D S; Shokhina, A G; Lukyanov, S A; Belousov, V V

    2015-01-01

    Most of the living cells maintain the continuous flow of electrons, which provides them by energy. Many of the compounds are presented in a cell at the same time in the oxidized and reduced states, forming the active redox couples. Some of the redox couples, such as NAD+/NADH, NADP+/NADPH, oxidized/reduced glutathione (GSSG/GSH), are universal, as they participate in adjusting of many cellular reactions. Ratios of the oxidized and reduced forms of these compounds are important cellular redox parameters. Modern research approaches allow setting the new functions of the main redox couples in the complex organization of cellular processes. The following information is about the main cellular redox couples and their participation in various biological processes.

  13. Behavioural indicators of welfare in farmed fish.

    PubMed

    Martins, Catarina I M; Galhardo, Leonor; Noble, Chris; Damsgård, Børge; Spedicato, Maria T; Zupa, Walter; Beauchaud, Marilyn; Kulczykowska, Ewa; Massabuau, Jean-Charles; Carter, Toby; Planellas, Sònia Rey; Kristiansen, Tore

    2012-02-01

    Behaviour represents a reaction to the environment as fish perceive it and is therefore a key element of fish welfare. This review summarises the main findings on how behavioural changes have been used to assess welfare in farmed fish, using both functional and feeling-based approaches. Changes in foraging behaviour, ventilatory activity, aggression, individual and group swimming behaviour, stereotypic and abnormal behaviour have been linked with acute and chronic stressors in aquaculture and can therefore be regarded as likely indicators of poor welfare. On the contrary, measurements of exploratory behaviour, feed anticipatory activity and reward-related operant behaviour are beginning to be considered as indicators of positive emotions and welfare in fish. Despite the lack of scientific agreement about the existence of sentience in fish, the possibility that they are capable of both positive and negative emotions may contribute to the development of new strategies (e.g. environmental enrichment) to promote good welfare. Numerous studies that use behavioural indicators of welfare show that behavioural changes can be interpreted as either good or poor welfare depending on the fish species. It is therefore essential to understand the species-specific biology before drawing any conclusions in relation to welfare. In addition, different individuals within the same species may exhibit divergent coping strategies towards stressors, and what is tolerated by some individuals may be detrimental to others. Therefore, the assessment of welfare in a few individuals may not represent the average welfare of a group and vice versa. This underlines the need to develop on-farm, operational behavioural welfare indicators that can be easily used to assess not only the individual welfare but also the welfare of the whole group (e.g. spatial distribution). With the ongoing development of video technology and image processing, the on-farm surveillance of behaviour may in the near

  14. Whole School Behaviour Management and Perceptions of Behaviour Problems in Australian Primary Schools

    ERIC Educational Resources Information Center

    De Nobile, John; London, Teola; El Baba, Mariam

    2015-01-01

    Over the past decade and a half, whole school behaviour management systems have been implemented in many Australian schools in efforts to reduce undesirable behaviours and improve outcomes for students with behaviour problems. There is evidence in the literature suggesting that whole school approaches are more effective at managing student…

  15. The Efficacy of Positive Behavioural Support with the Most Challenging Behaviour: The Evidence and Its Implications

    ERIC Educational Resources Information Center

    LaVigna, Gary W.; Willis, Thomas J.

    2012-01-01

    Background: Positive behaviour support (PBS) is behaviour analysis applied in support of people with challenging behaviour. Questions have been raised as to PBS effectiveness, costs, and accessibility. Method: Outcome studies meeting specified criteria for PBS were selected for review. All told, 12 outcome studies encompassing 423 cases were…

  16. Behavioural responses to influenza pandemics

    PubMed Central

    Balinska, Marta; Rizzo, Caterina

    2009-01-01

    The emergence of the novel A/H1N1 virus has made pandemic preparedness a crucial issue for public health worldwide. Although the epidemiological aspects of the three 20th century influenza pandemics have been widely investigated, little is known about population behaviour in a pandemic situation. Such knowledge is however critical, notably for predicting population compliance with non pharmaceutical interventions. This paper reviews the relevant scientific literature for the 1918-1920, 1957-1958, 1969-1969 influenza epidemics and the 2003 SARS outbreak. Although the evidence base of most non pharmaceutical interventions (NPIs) and personal protection measures is debated, it appears on the basis of past experience that NPIs implemented the most systematically, the earliest, and for the longest time could reduce overall mortality rates and spread out epidemic peaks. Adequate, transparent, and targeted communication on the part of public health authorities would be also of crucial importance in the event of a serious influenza pandemic. PMID:20025201

  17. Coordinated Behaviour in Pigeon Flocks

    PubMed Central

    Yomosa, Makoto; Mizuguchi, Tsuyoshi; Vásárhelyi, Gábor; Nagy, Máté

    2015-01-01

    We analysed pigeon flock flights using GPS trajectory data to reveal the most important kinematic aspects of flocking behaviour. We quantitatively investigated the internal motion of the flock based on pairwise statistics and found the following general relationships in all datasets: i) the temporal order of decisions characterised by the delay between directional changes is strictly related to the spatial order characterised by the longitudinal relative position within the flock; ii) during circling motion, pigeons use a mixture of two idealised and fundamentally different turning strategies, namely, parallel-path and equal-radius type turning. While pigeons tend to maintain their relative position within the flock on average, as in the parallel-path approximation, those who turn later also get behind as in the equal-radius case. Equal-radius type turning also tends to be expressed more during smaller radius turns. PMID:26485662

  18. Clouding behaviour in surfactant systems.

    PubMed

    Mukherjee, Partha; Padhan, Susanta K; Dash, Sukalyan; Patel, Sabita; Mishra, Bijay K

    2011-02-17

    A study on the phenomenon of clouding and the applications of cloud point technology has been thoroughly discussed. The phase behaviour of clouding and various methods adopted for the determination of cloud point of various surfactant systems have been elucidated. The systems containing anionic, cationic, nonionic surfactants as well as microemulsions have been reviewed with respect to their clouding phenomena and the effects of structural variation in the surfactant systems have been incorporated. Additives of various natures control the clouding of surfactants. Electrolytes, nonelectrolytes, organic substances as well as ionic surfactants, when present in the surfactant solutions, play a major role in the clouding phenomena. The review includes the morphological study of clouds and their applications in the extraction of trace inorganic, organic materials as well as pesticides and protein substrates from different sources.

  19. Behaviour during a cluster headache.

    PubMed

    Blau, J N

    1993-09-18

    Because cluster headache is short-lasting and tends to occur during the early morning hours, physicians rarely witness an attack. Accurate diagnosis is important because effective treatments are available. The diagnosis is made from the history of temporal pattern, reddening and tearing of the affected eye, and ipsilateral nasal congestion. An additional diagnostic aid is to invite patients to demonstrate how they respond to attacks. The pain, one of the worst known, causes extreme restlessness. 50 patients showed how they walk around, sit (or kneel) and rock, and clutch the affected side of the head. Diagnostic value apart, the patient will often be relieved to learn that bizarre behavioural responses are not a mark of insanity.

  20. Clouding behaviour in surfactant systems.

    PubMed

    Mukherjee, Partha; Padhan, Susanta K; Dash, Sukalyan; Patel, Sabita; Mishra, Bijay K

    2011-02-17

    A study on the phenomenon of clouding and the applications of cloud point technology has been thoroughly discussed. The phase behaviour of clouding and various methods adopted for the determination of cloud point of various surfactant systems have been elucidated. The systems containing anionic, cationic, nonionic surfactants as well as microemulsions have been reviewed with respect to their clouding phenomena and the effects of structural variation in the surfactant systems have been incorporated. Additives of various natures control the clouding of surfactants. Electrolytes, nonelectrolytes, organic substances as well as ionic surfactants, when present in the surfactant solutions, play a major role in the clouding phenomena. The review includes the morphological study of clouds and their applications in the extraction of trace inorganic, organic materials as well as pesticides and protein substrates from different sources. PMID:21296314

  1. Coordinated Behaviour in Pigeon Flocks.

    PubMed

    Yomosa, Makoto; Mizuguchi, Tsuyoshi; Vásárhelyi, Gábor; Nagy, Máté

    2015-01-01

    We analysed pigeon flock flights using GPS trajectory data to reveal the most important kinematic aspects of flocking behaviour. We quantitatively investigated the internal motion of the flock based on pairwise statistics and found the following general relationships in all datasets: i) the temporal order of decisions characterised by the delay between directional changes is strictly related to the spatial order characterised by the longitudinal relative position within the flock; ii) during circling motion, pigeons use a mixture of two idealised and fundamentally different turning strategies, namely, parallel-path and equal-radius type turning. While pigeons tend to maintain their relative position within the flock on average, as in the parallel-path approximation, those who turn later also get behind as in the equal-radius case. Equal-radius type turning also tends to be expressed more during smaller radius turns.

  2. Coordinated Behaviour in Pigeon Flocks.

    PubMed

    Yomosa, Makoto; Mizuguchi, Tsuyoshi; Vásárhelyi, Gábor; Nagy, Máté

    2015-01-01

    We analysed pigeon flock flights using GPS trajectory data to reveal the most important kinematic aspects of flocking behaviour. We quantitatively investigated the internal motion of the flock based on pairwise statistics and found the following general relationships in all datasets: i) the temporal order of decisions characterised by the delay between directional changes is strictly related to the spatial order characterised by the longitudinal relative position within the flock; ii) during circling motion, pigeons use a mixture of two idealised and fundamentally different turning strategies, namely, parallel-path and equal-radius type turning. While pigeons tend to maintain their relative position within the flock on average, as in the parallel-path approximation, those who turn later also get behind as in the equal-radius case. Equal-radius type turning also tends to be expressed more during smaller radius turns. PMID:26485662

  3. Visco-elastic fluid simulations of coherent structures in strongly coupled dusty plasma medium

    SciTech Connect

    Singh Dharodi, Vikram; Kumar Tiwari, Sanat; Das, Amita

    2014-07-15

    A generalized hydrodynamic model depicting the behaviour of visco-elastic fluids has often been invoked to explore the behaviour of a strongly coupled dusty plasma medium below their crystallization limit. The model has been successful in describing the collective normal modes of the strongly coupled dusty plasma medium observed experimentally. The paper focuses on the study of nonlinear dynamical characteristic features of this model. Specifically, the evolution of coherent vorticity patches is being investigated here within the framework of this model. A comparison with Newtonian fluids and molecular dynamics simulations treating the dust species interacting through the Yukawa potential has also been presented.

  4. Neural substrates of driving behaviour

    PubMed Central

    Spiers, Hugo J.; Maguire, Eleanor A.

    2007-01-01

    Driving a vehicle is an indispensable daily behaviour for many people, yet we know little about how it is supported by the brain. Given that driving in the real world involves the engagement of many cognitive systems that rapidly change to meet varying environmental demands, identifying its neural basis presents substantial problems. By employing a unique combination of functional magnetic resonance imaging (fMRI), an accurate interactive virtual simulation of a bustling central London (UK) and a retrospective verbal report protocol, we surmounted these difficulties. We identified different events that characterise the driving process on a second by second basis and the brain regions that underlie them. Prepared actions such as starting, turning, reversing and stopping were associated with a common network comprised of premotor, parietal and cerebellar regions. Each prepared action also recruited additional brain areas. We also observed unexpected hazardous events such as swerving and avoiding collisions that were associated with activation of lateral occipital and parietal regions, insula, as well as a more posterior region in the medial premotor cortex than prepared actions. By contrast, planning future actions and monitoring fellow road users were associated with activity in superior parietal, lateral occipital cortices and the cerebellum. The anterior pre-SMA was also recruited during action planning. The right lateral prefrontal cortex was specifically engaged during the processing of road traffic rules. By systematically characterising the brain dynamics underlying naturalistic driving behaviour in a real city, our findings may have implications for how driving competence is considered in the context of neurological damage. PMID:17412611

  5. Shock transmission in a coupled beam system

    NASA Astrophysics Data System (ADS)

    Vijayan, K.; Woodhouse, J.

    2013-08-01

    This paper investigates the circumstances under which high peak acceleration can occur in the internal parts of a system when subjected to impulsive driving on the outside. Motivating examples include the design of packaging for transportation of fragile items. The system is modelled in an idealised form using two beams coupled with point connections. A Rayleigh-Ritz model of such coupled beams was validated against measurements on a particular beam system, then the model was used to explore the acceleration response to impulsive driving in the time, frequency and spatial domains. This study is restricted to linear vibration response and additional mechanisms for high internal acceleration due to nonlinear effects such as internal impacts are not considered. Using Monte Carlo simulation in which the indirectly driven beam was perturbed by randomly placed point masses a wide range of system behaviour was explored. This facilitates identification of vulnerable configurations that can lead to high internal acceleration. The results from the study indicate the possibility of curve veering influencing the peak acceleration amplification. The possibility of veering within an ensemble was found to be dependent on the relative coupling strength of the modes. Understanding of the mechanism may help to avoid vulnerable cases, either by design or by preparatory vibration testing.

  6. Behavioural activation: history, evidence and promise.

    PubMed

    Kanter, Jonathan W; Puspitasari, Ajeng J; Santos, Maria M; Nagy, Gabriela A

    2012-05-01

    Behavioural activation holds promise to reduce the global burden of depression as a treatment approach that is effective, easy to teach, scalable and acceptable to providers and patients across settings and cultures. This editorial reviews the history of behavioural activation, what it is, current evidence for its use and future directions.

  7. Identifying Russian and Finnish Adolescents' Problem Behaviours

    ERIC Educational Resources Information Center

    Kemppainen, Ulla; Tossavainen, Kerttu; Vartiainen, Erkki; Puska, Pekka; Jokela, Veikko; Pantelejev, Vladimir; Uhanov, Mihail

    2007-01-01

    Purpose: The purpose of the paper is to show that a syndrome of problem behaviours, i.e. early substance abuse, school and family problems and sexual promiscuity impairs normal development in adolescence. This comparative study looked for differences in the problem behaviour profiles of 15-year-old adolescents in the Pitkaranta district in Russia…

  8. Training Staff to Manage Challenging Behaviour

    ERIC Educational Resources Information Center

    van Oorsouw, Wietske M. W. J.; Embregts, Petri J. C. M.; Bosman, Anna M. T.; Jahoda, Andrew

    2010-01-01

    Background: A training package for staff working with clients presenting challenging behaviour was developed to (1) increase their knowledge regarding challenging behaviour, and (2) to improve the quality of physical intervention techniques. The latter aim was intended to reduce staff anxiety about dealing with incidents and limit physical risk of…

  9. Evolutionary accounts of human behavioural diversity

    PubMed Central

    Brown, Gillian R.; Dickins, Thomas E.; Sear, Rebecca; Laland, Kevin N.

    2011-01-01

    Human beings persist in an extraordinary range of ecological settings, in the process exhibiting enormous behavioural diversity, both within and between populations. People vary in their social, mating and parental behaviour and have diverse and elaborate beliefs, traditions, norms and institutions. The aim of this theme issue is to ask whether, and how, evolutionary theory can help us to understand this diversity. In this introductory article, we provide a background to the debate surrounding how best to understand behavioural diversity using evolutionary models of human behaviour. In particular, we examine how diversity has been viewed by the main subdisciplines within the human evolutionary behavioural sciences, focusing in particular on the human behavioural ecology, evolutionary psychology and cultural evolution approaches. In addition to differences in focus and methodology, these subdisciplines have traditionally varied in the emphasis placed on human universals, ecological factors and socially learned behaviour, and on how they have addressed the issue of genetic variation. We reaffirm that evolutionary theory provides an essential framework for understanding behavioural diversity within and between human populations, but argue that greater integration between the subfields is critical to developing a satisfactory understanding of diversity. PMID:21199836

  10. Managing Disruptive Behaviour in the Classroom

    ERIC Educational Resources Information Center

    Deering, Catherine

    2011-01-01

    Both faculty and students at many colleges and universities report numerous incidents of disruptive and uncivil behaviour. However, studies show that faculty are often reluctant to confront these situations, or they feel ill-equipped to intervene. If the behaviour escalates, a disproportionate amount of time and effort can be spent trying to…

  11. The Behavioural Phenotype of Angelman Syndrome

    ERIC Educational Resources Information Center

    Horsler, K.; Oliver, C.

    2006-01-01

    Background: The purpose of this review is to examine the notion of a behavioural phenotype for Angelman syndrome and identify methodological and conceptual influences on the accepted presentation. Methods: Studies examining the behavioural characteristics associated with Angelman syndrome are reviewed and methodology is described. Results:…

  12. Information Searching Behaviour of Young Slovenian Researchers

    ERIC Educational Resources Information Center

    Vilar, Polona; Zumer, Maja

    2011-01-01

    Purpose: The purpose of this paper is to present the findings of an empirical study of information behaviour of young Slovenian researchers. Design/methodology/approach: Built on some well-known models of scholarly information behaviour the study complements a previously conducted study of the same population, which focused on the aspects of user…

  13. The Construction of Emotional and Behavioural Difficulties

    ERIC Educational Resources Information Center

    Jones, Raya A.

    2003-01-01

    This paper presents a critique of the educational model of emotional and behavioural difficulties in British education. In the wake of strong criticisms of the so-called medical model of maladjustment (pre-1980s), educational policies have defined the "disturbing" pupil as having emotional and behavioural difficulties, and have more recently…

  14. Parental Communication and Youth Sexual Behaviour

    ERIC Educational Resources Information Center

    Aspy, Cheryl B.; Vesely, Sara K.; Oman, Roy F.; Rodine, Sharon; Marshall, LaDonna; McLeroy, Ken

    2007-01-01

    The role of parental communication and instruction concerning sexual behaviour were studied in a community-based sample of 1083 youth aged 13-17 (mean age of 15 years; 51% girls, 49% White). The Youth Asset Survey was administered along with items measuring demographics and youth risk behaviours. After controlling for demographic factors,…

  15. Mobbing Behaviour: Victims and the Affected

    ERIC Educational Resources Information Center

    Erturk, Abbas

    2013-01-01

    The purpose of this research was to identify the level of mobbing behaviour faced by teachers and managers working in primary schools, their responses to such behaviour and the difference in these responses according to the gender variable. The sample of the research consists of a total of 1,316 teachers and managers including 691 men and 625…

  16. Behavioural outcomes of perinatal maternal fluoxetine treatment.

    PubMed

    McAllister, B B; Kiryanova, V; Dyck, R H

    2012-12-13

    During and following pregnancy, women are at considerable risk of experiencing depression. For treatment, selective serotonin reuptake inhibitor drugs, such as fluoxetine, are commonly prescribed, yet the potential effects of perinatal exposure to these drugs on the brain and behaviour have not been examined in humans beyond childhood. This is despite abundant evidence from studies using rodents indicating that altered serotonin levels early in life affect neurodevelopment and behavioural outcomes. These reported effects on behaviour are inconsistent, however, and the testing of females has often been overlooked. In the present study, the behavioural outcomes of female mice perinatally (embryonic day 15 to postnatal day 12) treated with fluoxetine (25mg/kg/day) via a non-stressful method of maternal administration were assessed using a battery of tests. Maternal treatment resulted in subtle alterations in anxiety-like and depression-like behaviour in early adulthood, with a decrease in both types of behaviour as well as body weight. Though altered anxiety and depression have previously been reported in this area of research, decreased anxiety is a novel finding. While there was little effect of perinatal maternal fluoxetine treatment on many of the behaviours assessed, the capacity to alter "emotional" behaviours in mice has implications with regard to research on human infant fluoxetine exposure.

  17. Health-Promoting Behaviours in Conservatoire Students

    ERIC Educational Resources Information Center

    Kreutz, Gunter; Ginsborg, Jane; Williamon, Aaron

    2009-01-01

    This study focuses on health-promoting behaviours in students from two conservatoires, the Royal Northern College of Music (RNCM, Manchester, UK; n =199) and the Royal College of Music (RCM, London, UK; n = 74). The research questions concern (a) the levels and types of health-promoting behaviours among performance students and (b) the association…

  18. Behavioural Approaches to Understanding Student Choice

    ERIC Educational Resources Information Center

    Diamond, Abigail; Vorley, Tim; Roberts, Jennifer; Jones, Stephen

    2012-01-01

    The Higher Education Academy (HEA), in partnership with the National Union of Students (NUS), commissioned CFE and The University of Sheffield to undertake research to explore behavioural approaches to understanding student choice. Within the research, the authors' applied insights from behavioural economics to help aid understanding of student…

  19. Integrated Programs and Pro-Environmental Behaviour

    ERIC Educational Resources Information Center

    Smith, Tiffany

    2008-01-01

    Research suggested that "nature experience as an education method played a role in developing environmental value and attitudes, and was influential in pro-environmental behaviour." Few of these studies however, assessed the long-term influences of outdoor education experiences on participants' pro-environmental behaviour. The Outward Bound Canada…

  20. Identifying Successful Learners from Interaction Behaviour

    ERIC Educational Resources Information Center

    McCuaig, Judi; Baldwin, Julia

    2012-01-01

    The interaction behaviours of successful, high-achieving learners when using a Learning Management System (LMS) are different than the behaviours of learners who are having more difficulty mastering the course material. This paper explores the idea that conventional Learning Management Systems can exploit data mining techniques to predict the…

  1. Evidence-Based Classroom Behaviour Management Strategies

    ERIC Educational Resources Information Center

    Parsonson, Barry S.

    2012-01-01

    This paper reviews a range of evidence-based strategies for application by teachers to reduce disruptive and challenging behaviours in their classrooms. These include a number of antecedent strategies intended to help minimise the emergence of problematic behaviours and a range of those which provide positive consequences for appropriate student…

  2. Effects of laboratory colonization on Bactrocera dorsalis (Diptera, Tephritidae) mating behaviour: ‘what a difference a year makes’

    PubMed Central

    Schutze, Mark K.; Dammalage, Thilak; Jessup, Andrew; Vreysen, Marc J.B.; Wornoayporn, Viwat; Clarke, Anthony R.

    2015-01-01

    Abstract Laboratory-reared insects are widely known to have significantly reduced genetic diversity in comparison to wild populations; however, subtle behavioural changes between laboratory-adapted and wild or ‘wildish’ (i.e., within one or very few generations of field collected material) populations are less well understood. Quantifying alterations in behaviour, particularly sexual, in laboratory-adapted insects is important for mass-reared insects for use in pest management strategies, especially those that have a sterile insect technique component. We report subtle changes in sexual behaviour between ‘wildish’ Bactrocera dorsalis flies (F1 and F2) from central and southern Thailand and the same colonies 12 months later when at six generations from wild. Mating compatibility tests were undertaken under standardised semi-natural conditions, with number of homo/heterotypic couples and mating location in field cages analysed via compatibility indices. Central and southern populations of Bactrocera dorsalis displayed positive assortative mating in the 2010 trials but mated randomly in the 2011 trials. ‘Wildish’ southern Thailand males mated significantly earlier than central Thailand males in 2010; this difference was considerably reduced in 2011, yet homotypic couples from southern Thailand still formed significantly earlier than all other couple combinations. There was no significant difference in couple location in 2010; however, couple location significantly differed among pair types in 2011 with those involving southern Thailand females occurring significantly more often on the tree relative to those with central Thailand females. Relative participation also changed with time, with more southern Thailand females forming couples relative to central Thailand females in 2010; this difference was considerably decreased by 2011. These results reveal how subtle changes in sexual behaviour, as driven by laboratory rearing conditions, may significantly

  3. Rapid integrated rheo-optical and polarized Fourier-transform infrared spectrometry measurement system for polymer films undergoing chemo-mechanical changes.

    PubMed

    Unsal, E; Nugay, I I; Offenbach, I; Gross, M; Manning, C; Cakmak, M

    2013-07-01

    The design and performance of a multisensory instrument to track physical and chemical changes of thin polymer films (typically 5 μm < thickness < 100 μm) subjected to thermal and mechanical treatments are described in this paper. For the first time, real-time measurements of spectral birefringence, true stress, true strain, and temperature are integrated together with ultra-rapid-scan polarized FT-IR spectrometer (URS-FT-IR) to investigate the relationships between true mechanical measures and structural features at different length scales. The rheo-optical properties (birefringence-true stress-true strain) are collected at a rate of 10 data points∕s and URS-FT-IR data are collected at a rate of 300 complete spectra∕s. The IR dichroism measurement is performed by exposing the sample to non-polarized IR beam in transmission mode with two mutually perpendicular polarizations, parallel and perpendicular to the stretching direction, received by detector unit. This design allows to analyze both polarizations simultaneously wavenumbers in the range of 500 cm(-1)-4000 cm(-1). Controlled processing parameters include air speed, air temperature, stretching rate, stretching ratio, stretch cycling, and holding times; while simultaneously measuring optical retardation, sample width, temperature, load cell, and both parallel and perpendicular IR spectra. Calibration and performance of this instrument is demonstrated with several film samples. These are: A polystyrene standard, an atactic polystyrene (homo-polymer), a polyurethane (consists of hard and soft segments) for physical changes during uniaxial deformation, and a polyamic acid during imidization reaction. This measurement system is particularly useful in unraveling molecular level details of complex physical and chemical events that take place during very fast deformation schemes (uniaxial stretching, retraction, relaxation, annealing, etc.) relevant to industrial processes. These include specific orientation behavior of each phase, block or filler, crystallization, relaxation and orientation state. It is also suited to track reaction rates and products in polymers undergoing thermal or photo curing. PMID:23902078

  4. Feeding behaviour of Black Sea bottom fishes: Did it change over time?

    NASA Astrophysics Data System (ADS)

    Bănaru, Daniela; Harmelin-Vivien, Mireille

    2009-11-01

    This study was designed to improve knowledge in feeding behaviour of the round goby ( Apollonia melanostomus (Pallas, 1814)), the red mullet ( Mullus barbatus ponticus Essipov, 1927), the whiting ( Merlangius merlangus (Linnaeus, 1758)), the flounder ( Platichthys flesus (Linnaeus, 1758)), the sole ( Solea solea (Linnaeus, 1758)), the turbot ( Psetta maeotica (Pallas, 1814)) and the starry sturgeon ( Acipenser stellatus Pallas, 1771) from the north-western Black Sea. Gut content coupled with stable isotope analysis allowed describing food web variations according to species, in two seasons and at two areas located seawards the Danube River. Present results showed that most fishes have likely changed their feeding behaviour compared to past studies from the same area. Trophic niches were reduced and dietary overlap was common, as different fish species consumed the same dominant prey types. Fishes probably adapted their feeding behaviour to the increasingly low biodiversity of the Black Sea communities.

  5. [Orthorectic eating behaviour - nosology and prevalence rates].

    PubMed

    Barthels, Friederike; Pietrowsky, Reinhard

    2012-12-01

    Orthorectic eating behaviour is characterised by a fixation on a healthy diet and rigidity regarding self-imposed nutrition standards. Besides malnutrition, subjective distress and social isolation might be consequences of clinical relevance. So far there are few reliable data about nosology and prevalence rates, so that it is not yet possible to evaluate the clinical significance of orthorectic eating behaviour. This article discusses nosological classifications of orthorexia and presents prevalence rates of extremely healthy eating behaviour in general population as well as in several specific subgroups. To summarise, orthorectic eating behaviour seems to be most likely an eating disorder with healthy dieting as an overvalued idea. Data on prevelance of orthorectic eating behaviour, assessed with the recently developed Düsseldorfer Orthorexie Skala, suggest a rate of 1 to 2% in general population. PMID:22700108

  6. [Orthorectic eating behaviour - nosology and prevalence rates].

    PubMed

    Barthels, Friederike; Pietrowsky, Reinhard

    2012-12-01

    Orthorectic eating behaviour is characterised by a fixation on a healthy diet and rigidity regarding self-imposed nutrition standards. Besides malnutrition, subjective distress and social isolation might be consequences of clinical relevance. So far there are few reliable data about nosology and prevalence rates, so that it is not yet possible to evaluate the clinical significance of orthorectic eating behaviour. This article discusses nosological classifications of orthorexia and presents prevalence rates of extremely healthy eating behaviour in general population as well as in several specific subgroups. To summarise, orthorectic eating behaviour seems to be most likely an eating disorder with healthy dieting as an overvalued idea. Data on prevelance of orthorectic eating behaviour, assessed with the recently developed Düsseldorfer Orthorexie Skala, suggest a rate of 1 to 2% in general population.

  7. [Self aggressive-behaviours in prison].

    PubMed

    Ammar, Malek M; Borras, L; Eytan, A

    2008-01-01

    Suicide among prisoners is a relatively well documented public health issue. On the other hand, data about self-aggressive behaviours in prisons are scarce, despite the fact that this problem seems to be highly prevalent. We conducted a retrospective study over a fifteen months period in a remand prison situated in the French speaking area of Switzerland. During this time period, 161 self-aggressive behaviours were recorded, corresponding to 80 inmates. The most frequent acts were self-cuttings and self-mutilations, followed by strangulations. All these patients were male and their mean age was 25. Some of these behaviours (ingesting cutting objects and sewing of the lips) were specific to some ethno-cultural groups. Copycat behaviours play a significant role in closed communities such as prisons. These results underline the necessity of taking into account self-aggressive behaviours in penitentiary institutions. PMID:19024369

  8. microRNA-encoded behaviour in Drosophila+

    PubMed Central

    Picao-Osorio, Joao; Johnston, Jamie; Landgraf, Matthias; Berni, Jimena; Alonso, Claudio R.

    2016-01-01

    The relationship between microRNA regulation and the specification of behaviour is only beginning to be explored. Here we find that mutation of a single microRNA locus (miR-iab4/8) in Drosophila larvae affects the animal’s capacity to correct its orientation if turned upside-down (self-righting). One of the microRNA targets involved in this behaviour is the Hox gene Ultrabithorax whose derepression in two metameric neurons leads to self-righting defects. In vivo neural activity analysis reveals that these neurons, the self-righting node (SRN), have different activity patterns in wild type and miRNA mutants whilst thermogenetic manipulation of SRN activity results in changes in self-righting behaviour. Our work thus reveals a microRNA-encoded behaviour and suggests that other microRNAs might also be involved in behavioural control in Drosophila and other species. PMID:26494171

  9. Behavioural techniques to reduce self-injurious behaviour in children with autism.

    PubMed

    Howlin, P

    1993-01-01

    This paper is part of a special section on 'self-injurious behaviour and autism' and concentrates on behavioural treatment techniques available and useful to reduce self-injurious behaviour in children with autism (e.g. extinction, time-out, differential reinforcement, alternative forms of stimulation, sensory deprivation, physical restraint, crisis management, environmental modifications). It has become increasingly evident that the successful treatment of self-injurious behaviour requires, first, a systematic and detailed (functional) analysis of the variables associated with the behaviour and, second, a hypothesis-testing approach on an individual, naturalistic basis to increase the acquisition of alternative skills and self-control. PMID:8135115

  10. Semiclassical theory of coupled lasers

    SciTech Connect

    Shakir, S.A.; Chow, W.W.

    1985-08-01

    The semiclassical equations of motion for a system of coupled lasers are developed and the frequency locking of the lasers comprising the system is analyzed. It is shown that the frequency-coupling range, in terms of the coupled cavities' mismatch, is proportional to the coupling coefficient. For a system where the cavities are uniformally filled with the active medium, the coupling vanishes regardless of the transmittance of the coupling mirrors. Our theory is valid for all values of coupling and for any number of lasers in the array. It may also be adapted to study different types of coupling arrangements.

  11. Host behaviour-parasite feedback: an essential link between animal behaviour and disease ecology.

    PubMed

    Ezenwa, Vanessa O; Archie, Elizabeth A; Craft, Meggan E; Hawley, Dana M; Martin, Lynn B; Moore, Janice; White, Lauren

    2016-04-13

    Animal behaviour and the ecology and evolution of parasites are inextricably linked. For this reason, animal behaviourists and disease ecologists have been interested in the intersection of their respective fields for decades. Despite this interest, most research at the behaviour-disease interface focuses either on how host behaviour affects parasites or how parasites affect behaviour, with little overlap between the two. Yet, the majority of interactions between hosts and parasites are probably reciprocal, such that host behaviour feeds back on parasites and vice versa. Explicitly considering these feedbacks is essential for understanding the complex connections between animal behaviour and parasite ecology and evolution. To illustrate this point, we discuss how host behaviour-parasite feedbacks might operate and explore the consequences of feedback for studies of animal behaviour and parasites. For example, ignoring the feedback of host social structure on parasite dynamics can limit the accuracy of predictions about parasite spread. Likewise, considering feedback in studies of parasites and animal personalities may provide unique insight about the maintenance of variation in personality types. Finally, applying the feedback concept to links between host behaviour and beneficial, rather than pathogenic, microbes may shed new light on transitions between mutualism and parasitism. More generally, accounting for host behaviour-parasite feedbacks can help identify critical gaps in our understanding of how key host behaviours and parasite traits evolve and are maintained.

  12. Proteinase-activated receptor 2 is involved in the behavioural changes associated with sickness behaviour.

    PubMed

    Abulkassim, Roua; Brett, Ros; MacKenzie, Scott M; Bushell, Trevor J

    2016-06-15

    Proteinase-activated receptor-2 (PAR2) is widely expressed in the CNS but whether it plays a key role in inflammation-related behavioural changes remains unknown. Hence, in the present study we have examined whether PAR2 contributes to behaviour associated with systemic inflammation using PAR2 transgenic mice. The onset of sickness behaviour was delayed and the recovery accelerated in PAR2(-/-) mice in the LPS-induced model of sickness behaviour. In contrast, PAR2 does not contribute to behaviour under normal conditions. In conclusion, these data suggest that PAR2 does not contribute to behaviour in the normal healthy brain but it plays a role in inflammation-related behavioural changes.

  13. Coupled adaptive complex networks.

    PubMed

    Shai, S; Dobson, S

    2013-04-01

    Adaptive networks, which combine topological evolution of the network with dynamics on the network, are ubiquitous across disciplines. Examples include technical distribution networks such as road networks and the internet, natural and biological networks, and social science networks. These networks often interact with or depend upon other networks, resulting in coupled adaptive networks. In this paper we study susceptible-infected-susceptible (SIS) epidemic dynamics on coupled adaptive networks, where susceptible nodes are able to avoid contact with infected nodes by rewiring their intranetwork connections. However, infected nodes can pass the disease through internetwork connections, which do not change with time: The dependencies between the coupled networks remain constant. We develop an analytical formalism for these systems and validate it using extensive numerical simulation. We find that stability is increased by increasing the number of internetwork links, in the sense that the range of parameters over which both endemic and healthy states coexist (both states are reachable depending on the initial conditions) becomes smaller. Finally, we find a new stable state that does not appear in the case of a single adaptive network but only in the case of weakly coupled networks, in which the infection is endemic in one network but neither becomes endemic nor dies out in the other. Instead, it persists only at the nodes that are coupled to nodes in the other network through internetwork links. We speculate on the implications of these findings. PMID:23679478

  14. Coupled adaptive complex networks

    NASA Astrophysics Data System (ADS)

    Shai, S.; Dobson, S.

    2013-04-01

    Adaptive networks, which combine topological evolution of the network with dynamics on the network, are ubiquitous across disciplines. Examples include technical distribution networks such as road networks and the internet, natural and biological networks, and social science networks. These networks often interact with or depend upon other networks, resulting in coupled adaptive networks. In this paper we study susceptible-infected-susceptible (SIS) epidemic dynamics on coupled adaptive networks, where susceptible nodes are able to avoid contact with infected nodes by rewiring their intranetwork connections. However, infected nodes can pass the disease through internetwork connections, which do not change with time: The dependencies between the coupled networks remain constant. We develop an analytical formalism for these systems and validate it using extensive numerical simulation. We find that stability is increased by increasing the number of internetwork links, in the sense that the range of parameters over which both endemic and healthy states coexist (both states are reachable depending on the initial conditions) becomes smaller. Finally, we find a new stable state that does not appear in the case of a single adaptive network but only in the case of weakly coupled networks, in which the infection is endemic in one network but neither becomes endemic nor dies out in the other. Instead, it persists only at the nodes that are coupled to nodes in the other network through internetwork links. We speculate on the implications of these findings.

  15. Coordinated righting behaviour in locusts.

    PubMed

    Faisal, A A; Matheson, T

    2001-02-01

    A locust placed upside down on a flat surface uses a predictable sequence of leg movements to right itself. To analyse this behaviour, we made use of a naturally occurring state of quiescence (thanatosis) to position locusts in a standardised upside-down position from which they spontaneously right themselves. Locusts grasped around the pronotum enter a state of thanatosis during which the limbs can be manipulated into particular postures, where they remain, and the animal can be placed upside down on the ground. When released, thanatosis lasts 4-456 s (mean 73 s) before the animal suddenly becomes active again and rights itself within a further 600 ms. Thanatosis is characterised by very low levels of leg motor activity. During righting, one hind leg provides most of the downward force against the ground that rolls the body around a longitudinal axis towards the other side. The driving force is produced by femoral levation (relative to the body) at the trochanter and by tibial extension. As the animal rolls over, the hind leg on the other side is also levated at the trochanter, so that it does not obstruct the movement. The forelegs and middle legs are not required for successful righting but they can help initially to tip the locust to one side, and at the end of the movement they help stop the roll as the animal turns upright. Individual locusts have a preferred righting direction but can, nevertheless, roll to either side. Locusts falling upside down through the air use both passive and active mechanisms to right themselves before they land. Without active movements, falling locusts tend to rotate into an upright position, but most locusts extend their hind leg tibiae and/or spread their wings, which increases the success of mid-air righting from 28 to 49 % when falling from 30 cm. The rapid and reliable righting behaviour of locusts reduces the time spent in a vulnerable upside-down position. Their narrow body geometry, large hind legs, which can generate

  16. Coupled wedge waves.

    PubMed

    Abell, Bradley C; Pyrak-Nolte, Laura J

    2013-11-01

    The interface between two wedges can be treated as a displacement discontinuity characterized by elastic stiffnesses. By representing the boundary between the two quarter-spaces as a displacement discontinuity, coupled wedge waves were determined theoretically to be dispersive and to depend on the specific stiffness of the non-welded contact between the two wedges. Laboratory experiments on isotropic and anisotropic aluminum confirmed the theoretical prediction that the velocity of coupled wedge waves, for a non-welded interface, ranged continuously from the single wedge wave velocity at low stress to the Rayleigh velocity as the load applied normal to the interface was increased. Elastic waves propagating along the coupled wedges of two quarter-spaces in non-welded contact are found to exist theoretically even when the material properties of the two quarter-spaces are the same.

  17. Saturation in coupled oscillators

    NASA Astrophysics Data System (ADS)

    Roman, Ahmed; Hanna, James

    2015-03-01

    We consider a weakly nonlinear system consisting of a resonantly forced oscillator coupled to an unforced oscillator. It has long been known that, for quadratic nonlinearities and a 2:1 resonance between the oscillators, a perturbative solution of the dynamics exhibits a phenomenon known as saturation. At low forcing, the forced oscillator responds, while the unforced oscillator is quiescent. Above a critical value of the forcing, the forced oscillator's steady-state amplitude reaches a plateau, while that of the unforced oscillator increases without bound. We show that, contrary to established folklore, saturation is not unique to quadratically nonlinear systems. We present conditions on the form of the nonlinear couplings and resonance that lead to saturation. Our results elucidate a mechanism for localization or diversion of energy in systems of coupled oscillators, and suggest new approaches for the control or suppression of vibrations in engineered systems.

  18. The coupled nonlinear dynamics of a lift system

    NASA Astrophysics Data System (ADS)

    Crespo, Rafael Sánchez; Kaczmarczyk, Stefan; Picton, Phil; Su, Huijuan

    2014-12-01

    Coupled lateral and longitudinal vibrations of suspension and compensating ropes in a high-rise lift system are often induced by the building motions due to wind or seismic excitations. When the frequencies of the building become near the natural frequencies of the ropes, large resonance motions of the system may result. This leads to adverse coupled dynamic phenomena involving nonplanar motions of the ropes, impact loads between the ropes and the shaft walls, as well as vertical vibrations of the car, counterweight and compensating sheave. Such an adverse dynamic behaviour of the system endangers the safety of the installation. This paper presents two mathematical models describing the nonlinear responses of a suspension/ compensating rope system coupled with the elevator car / compensating sheave motions. The models accommodate the nonlinear couplings between the lateral and longitudinal modes, with and without longitudinal inertia of the ropes. The partial differential nonlinear equations of motion are derived using Hamilton Principle. Then, the Galerkin method is used to discretise the equations of motion and to develop a nonlinear ordinary differential equation model. Approximate numerical solutions are determined and the behaviour of the system is analysed.

  19. The coupled nonlinear dynamics of a lift system

    SciTech Connect

    Crespo, Rafael Sánchez E-mail: stefan.kaczmarczyk@northampton.ac.uk E-mail: huijuan.su@northampton.ac.uk; Kaczmarczyk, Stefan E-mail: stefan.kaczmarczyk@northampton.ac.uk E-mail: huijuan.su@northampton.ac.uk; Picton, Phil E-mail: stefan.kaczmarczyk@northampton.ac.uk E-mail: huijuan.su@northampton.ac.uk; Su, Huijuan E-mail: stefan.kaczmarczyk@northampton.ac.uk E-mail: huijuan.su@northampton.ac.uk

    2014-12-10

    Coupled lateral and longitudinal vibrations of suspension and compensating ropes in a high-rise lift system are often induced by the building motions due to wind or seismic excitations. When the frequencies of the building become near the natural frequencies of the ropes, large resonance motions of the system may result. This leads to adverse coupled dynamic phenomena involving nonplanar motions of the ropes, impact loads between the ropes and the shaft walls, as well as vertical vibrations of the car, counterweight and compensating sheave. Such an adverse dynamic behaviour of the system endangers the safety of the installation. This paper presents two mathematical models describing the nonlinear responses of a suspension/ compensating rope system coupled with the elevator car / compensating sheave motions. The models accommodate the nonlinear couplings between the lateral and longitudinal modes, with and without longitudinal inertia of the ropes. The partial differential nonlinear equations of motion are derived using Hamilton Principle. Then, the Galerkin method is used to discretise the equations of motion and to develop a nonlinear ordinary differential equation model. Approximate numerical solutions are determined and the behaviour of the system is analysed.

  20. [Couples counseling with Latinos].

    PubMed

    Zumaya, Mario

    2011-01-01

    Intimate ties and emotional relationship gain the function to confirm, to stabilize and, afterwards, to structure the coherency's model of the structured self-organization up to that moment. When the couple perceives the bond of the relationship such as a sole and exclusive for a person, they take a leading role to be able to deduce a sense of individuality and uniqueness in the way to feel himself in the world. Based on these considerations, in this paper I propose a brief description of a counselling method, which characterises the work I am carrying out since several years in the counselling and therapy with couples.

  1. Coupled transport protein systems.

    PubMed

    Thatcher, Jack D

    2013-04-16

    This set of animated lessons provides examples of how transport proteins interact in coupled systems to produce physiologic effects. The gastric pumps animation depicts the secretion of hydrochloric acid into the gastric lumen. The animation called glucose absorption depicts glucose absorption by intestinal epithelial cells. The CFTR animation explains how the cystic fibrosis conductance transmembrane regulator (CFTR) functions as a key component of a coupled system of transport proteins that clears the pulmonary system of mucus and inhaled particulates. These animations serve as valuable resources for any collegiate-level course that describes these processes. Courses that might use them include introductory biology, biochemistry, biophysics, cell biology, pharmacology, and physiology.

  2. Coupled moderator neutronics

    SciTech Connect

    Russell, G.J.; Pitcher, E.J.; Ferguson, P.D.

    1995-12-01

    Optimizing the neutronic performance of a coupled-moderator system for a Long-Pulse Spallation Source is a new and challenging area for the spallation target-system designer. For optimal performance of a neutron source, it is essential to have good communication with instrument scientists to obtain proper design criteria and continued interaction with mechanical, thermal-hydraulic, and materials engineers to attain a practical design. A good comprehension of the basics of coupled-moderator neutronics will aid in the proper design of a target system for a Long-Pulse Spallation Source.

  3. Wakefields and coupling impedances

    NASA Astrophysics Data System (ADS)

    Kurennoy, Sergey

    1995-02-01

    After a short introduction of the wake potentials and coupling impedances, a few new results in impedance calculations are discussed. The first example is a new analytical method for calculating impedances of axisymmetric structures in the low frequency range, below the cutoff frequency of the vacuum chamber. The second example demonstrates that even very small discontinuities on a smooth waveguide can result in appearance of trapped modes, with frequencies slightly below the waveguide cutoff frequency. The high-frequency (above the cutoff) behavior of the coupling impedance of many small discontinuities is discussed in the third example.

  4. Risk behaviour and noise exposure among adolescents.

    PubMed

    Bohlin, Margareta C; Erlandsson, Soly I

    2007-01-01

    Adolescents in Western society often expose themselves to high levels of sound in gyms, rock concerts, discotheques etc. As these behaviours are as threatening to young people's health as more traditional risk behaviours are, our aim in the present study was to analyze the relationship between self-exposure to noise, risk behaviours and risk judgements among 310 Swedish adolescents aged 15-20 (167 men; 143 women). Adolescents' behaviour in different traditional risk situations correlated with behaviour in noisy environments, while judgements about traditional risks correlated with judgements regarding noise exposure. It is an interesting finding that although young women judge risk situations as generally more dangerous than young men do, they nevertheless behave in the same way. We suggest that this difference is a social and cultural phenomenon which underscores the importance of adopting a gender perspective in the analysis of risk factors. Adolescents reporting permanent tinnitus judged loud music as more risky than adolescents with no symptoms and they did not listen to loud music as often as those with occasional tinnitus. Research on hearing prevention for young people needs to acknowledge and make use of theories on risk behaviour, especially due to the existence of a relationship between adolescents' risk-taking in noisy environments and other types of risk-taking. Similarly, theories on risk behaviour should acknowledge noise as a risk factor.

  5. Using robots to understand social behaviour.

    PubMed

    Mitri, Sara; Wischmann, Steffen; Floreano, Dario; Keller, Laurent

    2013-02-01

    A major challenge in studying social behaviour stems from the need to disentangle the behaviour of each individual from the resulting collective. One way to overcome this problem is to construct a model of the behaviour of an individual, and observe whether combining many such individuals leads to the predicted outcome. This can be achieved by using robots. In this review we discuss the strengths and weaknesses of such an approach for studies of social behaviour. We find that robots-whether studied in groups of simulated or physical robots, or used to infiltrate and manipulate groups of living organisms-have important advantages over conventional individual-based models and have contributed greatly to the study of social behaviour. In particular, robots have increased our understanding of self-organization and the evolution of cooperative behaviour and communication. However, the resulting findings have not had the desired impact on the biological community. We suggest reasons for why this may be the case, and how the benefits of using robots can be maximized in future research on social behaviour.

  6. Help-seeking behaviour: a concept analysis.

    PubMed

    Cornally, Nicola; McCarthy, Geraldine

    2011-06-01

    The concept 'help-seeking behaviour' has gained popularity in recent years as an important vehicle for exploring and understanding patient delay and prompt action across a variety of health conditions. The term is used interchangeably with health seeking and is described as part of both illness behaviour and health behaviour. Concept clarification is required to aid nurses and other health-care professionals understanding of the attributes of help-seeking behaviour and to guide theory development, practice and research. The Walker and Avant method of concept analysis was used to guide the analysis. Help-seeking behaviour was shown to be a complex decision-making process instigated by a problem that challenges personal abilities. According to the literature, the process is characterized by the following attributes: problem focused, intentional action and interpersonal interaction. Help-seeking behaviour for a health problem can therefore be defined as a problem focused, planned behaviour, involving interpersonal interaction with a selected health-care professional. PMID:21605269

  7. Dynamic Behaviour of Ventilated Hydrofoils.

    NASA Astrophysics Data System (ADS)

    Kjeldsen, Morten; Arndt, Roger; Wosnik, Martin

    2006-11-01

    In certain types of pumping applications oscillations are induced by operation with liquids containing a free gas load. In order to understand the physics of this process, a series of tests with a ventilated A 2D NACA 0015 hydrofoil were performed in the water tunnel at the St. Anthony Falls Laboratory of the University of Minnesota. The special bubble removal feature of the water tunnel allowed continuous ventilation without experiencing visible bubbles upstream the hydrofoil. These studies build on previous work on cavitation-induced oscillations. Gas injection studies were made over a range of gas flow rates and test section pressure. The results clearly show that lift oscillations increase in intensity when the gas load is increased. The point of maximum unsteadiness is also associated the rapid decline of the foil performance as measured as average lift. Further increase of the gas injection load gives a steady behaviour with almost no lift. These experiments are compared with traditional cavitation experiments. The similarities between gas injection- and cavitation induced unsteadiness on the hydrofoil are many, but the amplitude of lift oscillations found on the foil with gas injection corresponds to about 50% of that found for cavitating hydrofoils. The fact that the oscillations are periodic leads to the consideration of both passive and active control.

  8. Internal charge behaviour of nanocomposites

    NASA Astrophysics Data System (ADS)

    Nelson, J. Keith; Fothergill, John C.

    2004-05-01

    The incorporation of 23 nm titanium dioxide nanoparticles into an epoxy matrix to form a nanocomposite structure is described. It is shown that the use of nanometric particles results in a substantial change in the behaviour of the composite, which can be traced to the mitigation of internal charge when a comparison is made with conventional TiO2 fillers. A variety of diagnostic techniques (including dielectric spectroscopy, electroluminescence, thermally stimulated current and photoluminescence) have been used to augment pulsed electro-acoustic space charge measurement to provide a basis for understanding the underlying physics of the phenomenon. It would appear that, when the size of the inclusions becomes small enough, they act cooperatively with the host structure and cease to exhibit interfacial properties, leading to Maxwell-Wagner polarization. It is postulated that the particles are surrounded by high charge concentrations in the Gouy-Chapman-Stern layer. Since nanoparticles have very high specific areas, these regions allow limited charge percolation through nano-filled dielectrics. The practical consequences of this have also been explored in terms of the electric strength exhibited. It would appear that there was a window in which real advantages accrue from the nano-formulated material. An optimum loading of about 10% (by weight) is indicated.

  9. Static behaviour of induced seismicity

    NASA Astrophysics Data System (ADS)

    Mignan, Arnaud

    2016-04-01

    The standard paradigm to describe seismicity induced by fluid injection is to apply non-linear diffusion dynamics in a poroelastic medium. I show that the spatio-temporal behaviour and rate evolution of induced seismicity can, instead, be expressed by geometric operations on a static stress field produced by volume change at depth. I obtain laws similar in form to the ones derived from poroelasticity while requiring a lower description length. Although fluid flow is known to occur in the ground, it is not pertinent to the geometrical description of the spatio-temporal patterns of induced seismicity. The proposed model is equivalent to the static stress model for tectonic foreshocks generated by the Non-Critical Precursory Accelerating Seismicity Theory. This study hence verifies the explanatory power of this theory outside of its original scope and provides an alternative physical approach to poroelasticity for the modelling of induced seismicity. The applicability of the proposed geometrical approach is illustrated for the case of the 2006, Basel enhanced geothermal system stimulation experiment. Applicability to more problematic cases where the stress field may be spatially heterogeneous is also discussed.

  10. Nutritional behaviour differences in Germany.

    PubMed

    Thiel, C; Heinemann, L

    1996-01-01

    East- and west-German health inequalities that emerged in the 1960s and 1970s centered not only on cardiovascular mortality but also on lifestyle-dependent risk factors, thus a question that should be addressed is whether different dietary behaviours existed in the two sections of Germany. To answer this question, we examined two random-sample population surveys--MONICA in the east and VERA in the west--that were carried out during the late 1980s. In the eastern section of Germany, the consumption of milk, vegetable oil and fat, fresh vegetables and tropical fruits was much lower than that in the west, whereas the intake of sausages and butter was much higher. Consequently, the calorie intake in the east was higher for fat and lower for carbohydrates before reunification. Changes in dietary habits were anticipated in East Germany after reunification because of important changes in the food supply. Analysis of an east-German dietary survey that was carried out after the wall came down revealed that the improved food supply to the east, with more choices for planning a healthy diet, led to a favourable development in both macro- and micro-nutrient intake, more carbohydrates, vitamins, calcium, and potassium were consumed.

  11. Non-equilibrium Steady States in Kac's Model Coupled to a Thermostat

    NASA Astrophysics Data System (ADS)

    Evans, Josephine

    2016-09-01

    This paper studies the existence, uniqueness and convergence to non-equilibrium steady states in Kac's model with an external coupling. We work in both Fourier distances and Wasserstein distances. Our methods work in the case where the external coupling is not a Maxwellian equilibrium. This provides an example of a non-equilibrium steady state. We also study the behaviour as the number of particles goes to infinity and show quantitative estimates on the convergence rate of the first marginal.

  12. The behavioural ecology of climbing plants.

    PubMed

    Gianoli, Ernesto

    2015-02-12

    Climbing plants require an external support to grow vertically and enhance light acquisition. Vines that find a suitable support have greater performance and fitness than those that remain prostrate. Therefore, the location of a suitable support is a key process in the life history of climbing plants. Numerous studies on climbing plant behaviour have elucidated mechanistic details of support searching and attachment. Far fewer studies have addressed the ecological significance of support-finding behaviour and the factors that affect it. Without this knowledge, little progress can be made in the understanding of the evolution of support-finding behaviour in climbers. Here I review studies addressing ecological causes and consequences of support finding and use by climbing plants. I also propose the use of behavioural ecology theoretical frameworks to study climbing plant behaviour. I show how host tree attributes may determine the probability of successful colonization for the different types of climbers, and examine the evidence of environmental and genetic control of circumnutation behaviour and phenotypic responses to support availability. Cases of oriented vine growth towards supports are highlighted. I discuss functional responses of vines to the interplay between herbivory and support availability under different abiotic environments, illustrating with one study case how results comply with a theoretical framework of behavioural ecology originally conceived for animals. I conclude stressing that climbing plants are suitable study subjects for the application of behavioural-ecological theory. Further research under this framework should aim at characterizing the different stages of the support-finding process in terms of their fit with the different climbing modes and environmental settings. In particular, cost-benefit analysis of climbing plant behaviour should be helpful to infer the selective pressures that have operated to shape current climber ecological

  13. Distribution behaviour of acaricide cyflumetofen in tomato during home canning.

    PubMed

    Liu, Na; Dong, Fengshou; Chen, Zenglong; Xu, Jun; Liu, Xingang; Duan, Lifang; Li, Minmin; Zheng, Yongquan

    2016-05-01

    The distribution behaviour of cyflumetofen in tomatoes during home canning was studied. The targeted compound cyflumetofen was determined by ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) after each process step, which included washing, peeling, homogenisation, simmering and sterilisation. Results indicated that more cyflumetofen was removed by washing with detergent solution compared with tap water, 2% NaCl solution and 2% CH3COOH solution. Peeling resulted in 90.2% loss of cyflumetofen and was the most effective step at removing pesticide residues from tomatoes. The processing factors (PFs) of tomato samples after each step were generally less than 1; in particular, the PF of the peeling process for cyflumetofen was 0.28. PMID:27032623

  14. Impulsive and Compulsive Behaviours in Parkinson's disease

    PubMed Central

    Averbeck, BB; O’Sullivan, SS; Djamshidian, A

    2014-01-01

    Impulsive compulsive behaviours (ICBs) in Parkinson’s disease (PD) are a common and devastating side effect of dopamine replacement therapy. In this review we describe the phenomenology, prevalence and risk factors of these patients. Results of behavioural studies assessing the neuropsychological profile emphasize that the ICBs, which are behavioural addictions, are not hedonically motivated. Rather, other factors such as the inability to cope with uncertainty may be triggering ICBs. New insights from functional imaging studies, strengthening the incentive salience hypothesis are discussed and therapeutic guidelines for the management of ICBs in PD are given. PMID:24313567

  15. Precise Specification of Design Pattern Structure and Behaviour

    NASA Astrophysics Data System (ADS)

    Sterritt, Ashley; Clarke, Siobhán; Cahill, Vinny

    Applying design patterns while developing a software system can improve its non-functional properties, such as extensibility and loose coupling. Precise specification of structure and behaviour communicates the invariants imposed by a pattern on a conforming implementation and enables formal software verification. Many existing design-pattern specification languages (DPSLs) focus on class structure alone, while those that do address behaviour suffer from a lack of expressiveness and/or imprecise semantics. In particular, in a review of existing work, three invariant categories were found to be inexpressible in state-of-the-art DPSLs: dependency, object state and data-structure. This paper presents Alas: a precise specification language that supports design-pattern descriptions including these invariant categories. The language is based on UML Class and Sequence diagrams with modified syntax and semantics. In this paper, the meaning of the presented invariants is formalized and relevant ambiguities in the UML Standard are clarified. We have evaluated Alas by specifying the widely-used Gang of Four pattern catalog and identified patterns that benefitted from the added expressiveness and semantics of Alas.

  16. Coupled Oscillators with Chemotaxis

    NASA Astrophysics Data System (ADS)

    Sawai, Satoshi; Aizawa, Yoji

    1998-08-01

    A simple coupled oscillator system with chemotaxis is introducedto study morphogenesis of cellular slime molds. The modelsuccessfuly explains the migration of pseudoplasmodium which hasbeen experimentally predicted to be lead by cells with higherintrinsic frequencies. Results obtained predict that its velocityattains its maximum value in the interface region between totallocking and partial locking and also suggest possible rolesplayed by partial synchrony during multicellular development.

  17. Gravitationally coupled electroweak monopole

    NASA Astrophysics Data System (ADS)

    Cho, Y. M.; Kimm, Kyoungtae; Yoon, J. H.

    2016-10-01

    We present a family of gravitationally coupled electroweak monopole solutions in Einstein-Weinberg-Salam theory. Our result confirms the existence of globally regular gravitating electroweak monopole which changes to the magnetically charged black hole as the Higgs vacuum value approaches to the Planck scale. Moreover, our solutions could provide a more accurate description of the monopole stars and magnetically charged black holes.

  18. Coupling Gammasphere and ORRUBA

    SciTech Connect

    Ratkiewicz, A.; Cizewski, J. A.; Manning, B.; Pain, S. D.; Bardayan, D. W.; Blackmon, J. C.; Matos, M.; Chipps, K. A.; Hardy, S.; Shand, C.; Jones, K. L.; Kozub, R. L.; Lister, C. J.; Peters, W. A.; Seweryniak, D.

    2013-04-19

    The coincident detection of particles and gamma rays allows the study of the structure of exotic nuclei via inverse kinematics reactions using radioactive ion beams and thick targets. We report on the status of the project to couple the highresolution charged-particle detector ORRUBA to Gammasphere, a high-efficiency, high-resolution gamma ray detector.

  19. Coupled grain boundary motion in aluminium: the effect of structural multiplicity

    PubMed Central

    Cheng, Kuiyu; Zhang, Liang; Lu, Cheng; Tieu, Kiet

    2016-01-01

    The shear-induced coupled grain boundary motion plays an important role in the deformation of nanocrystalline (NC) materials. It has been known that the atomic structure of the grain boundary (GB) is not necessarily unique for a given set of misorientation and inclination of the boundary plane. However, the effect of the structural multiplicity of the GB on its coupled motion has not been reported. In the present study we investigated the structural multiplicity of the symmetric tilt Σ5(310) boundary in aluminium and its influence on the GB behaviour at a temperature range of 300 K–600 K using molecular dynamic simulations. Two starting atomic configurations were adopted in the simulations which resulted in three different GB structures at different temperatures. Under the applied shear deformation each GB structure exhibited its unique GB behaviour. A dual GB behaviour, namely the transformation of one GB behaviour to another during deformation, was observed for the second starting configuration at a temperature of 500 K. The atomistic mechanisms responsible for these behaviour were analysed in detail. The result of this study implicates a strong relationship between GB structures and their behaviour, and provides a further information of the grain boundary mediated plasticity in nanocrystalline materials. PMID:27140343

  20. Coupled grain boundary motion in aluminium: the effect of structural multiplicity.

    PubMed

    Cheng, Kuiyu; Zhang, Liang; Lu, Cheng; Tieu, Kiet

    2016-01-01

    The shear-induced coupled grain boundary motion plays an important role in the deformation of nanocrystalline (NC) materials. It has been known that the atomic structure of the grain boundary (GB) is not necessarily unique for a given set of misorientation and inclination of the boundary plane. However, the effect of the structural multiplicity of the GB on its coupled motion has not been reported. In the present study we investigated the structural multiplicity of the symmetric tilt Σ5(310) boundary in aluminium and its influence on the GB behaviour at a temperature range of 300 K-600 K using molecular dynamic simulations. Two starting atomic configurations were adopted in the simulations which resulted in three different GB structures at different temperatures. Under the applied shear deformation each GB structure exhibited its unique GB behaviour. A dual GB behaviour, namely the transformation of one GB behaviour to another during deformation, was observed for the second starting configuration at a temperature of 500 K. The atomistic mechanisms responsible for these behaviour were analysed in detail. The result of this study implicates a strong relationship between GB structures and their behaviour, and provides a further information of the grain boundary mediated plasticity in nanocrystalline materials. PMID:27140343

  1. Coupled grain boundary motion in aluminium: the effect of structural multiplicity

    NASA Astrophysics Data System (ADS)

    Cheng, Kuiyu; Zhang, Liang; Lu, Cheng; Tieu, Kiet

    2016-05-01

    The shear-induced coupled grain boundary motion plays an important role in the deformation of nanocrystalline (NC) materials. It has been known that the atomic structure of the grain boundary (GB) is not necessarily unique for a given set of misorientation and inclination of the boundary plane. However, the effect of the structural multiplicity of the GB on its coupled motion has not been reported. In the present study we investigated the structural multiplicity of the symmetric tilt Σ5(310) boundary in aluminium and its influence on the GB behaviour at a temperature range of 300 K–600 K using molecular dynamic simulations. Two starting atomic configurations were adopted in the simulations which resulted in three different GB structures at different temperatures. Under the applied shear deformation each GB structure exhibited its unique GB behaviour. A dual GB behaviour, namely the transformation of one GB behaviour to another during deformation, was observed for the second starting configuration at a temperature of 500 K. The atomistic mechanisms responsible for these behaviour were analysed in detail. The result of this study implicates a strong relationship between GB structures and their behaviour, and provides a further information of the grain boundary mediated plasticity in nanocrystalline materials.

  2. The impact of behavioural screening on intervention outcomes in a randomised, controlled multiple behaviour intervention trial

    PubMed Central

    2011-01-01

    Background With an increasing research focus on multiple health behaviour change interventions, a methodological issue requiring further investigation is whether or not to employ pre-trial behavioural screening to exclude participants who are achieving a pre-specified level of one or more behaviours. Behavioural screening can be used to direct limited resources to participants most in need of a behaviour change intervention; but may reduce the representativeness of the sample and limit comparability with trials that do not employ pre-trial behavioural screening. Furthermore, the impact of this type of screening on intervention participation and intervention effects is unknown. Methods Data for this study come from the Logan Healthy Living Program, a randomised, controlled telephone counselling lifestyle intervention trial which did not employ behavioural screening prior to randomisation. Screening for physical activity, diet or the combination was simulated using baseline trial data. To examine the impact of behavioural screening on intervention participation (in terms of participant characteristics, intervention dose received and retention), characteristics of participants included an excluded under the various screening scenarios were compared. To examine the impact of behavioural screening on intervention effects, results from the main trial analysis were compared with results obtained from the same analyses performed separately for each of the screened groups. Results Simulated pre-trial behavioural screening impacted minimally on intervention dose received and trial retention rate. Beyond the anticipated effect of reducing baseline levels of the behaviours being screened for, behavioural screening affected baseline levels of behaviours not targeted by screening, and participants' demographic and health-related characteristics. Behavioural screening impacted on intervention effects in ways that were anticipated and positive, but also unexpected and detrimental

  3. Attractor behaviour in ELKO cosmology

    NASA Astrophysics Data System (ADS)

    Basak, Abhishek; Bhatt, Jitesh R.; Shankaranarayanan, S.; Prasantha Varma, K. V.

    2013-04-01

    We study the dynamics of ELKO in the context of accelerated phase of our universe. To avoid the fine tuning problem associated with the initial conditions, it is required that the dynamical equations lead to an early-time attractor. In the earlier works, it was shown that the dynamical equations containing ELKO fields do not lead to early-time stable fixed points. In this work, using redefinition of variables, we show that ELKO cosmology admits early-time stable fixed points. More interestingly, we show that ELKO cosmology admit two sets of attractor points corresponding to slow and fast-roll inflation. The fast-roll inflation attractor point is unique for ELKO as it is independent of the form of the potential. We also discuss the plausible choice of interaction terms in these two sets of attractor points and constraints on the coupling constant.

  4. Unhealthy Behaviours: An International Comparison.

    PubMed

    Ferretti, Fabrizio

    2015-01-01

    In the current global economy, chronic non-communicable diseases (NCDs) have become the leading cause of death and a major health concern for both developed and developing countries. Among other factors, the worldwide spread of NCDs is driven by the globalisation of unhealthy habits. The purpose of this paper is to develop a simple statistic to measure, at the national level, the average population's exposure to the main NCDs modifiable risk factors. The approach and methodology followed by the United Nations Development Programme to compute the Human Development Index (HDI) is applied to four basic indicators of NCD-related preventable risk factors (alcohol consumption, excess caloric intake, non-balanced diet and tobacco use) in 112 countries worldwide in 2012-14. We obtain a summary composite index, which we call the Unhealthy Behaviour Index (UBI), which ranks countries by the average level of the unhealthy habits (drinking, eating and smoking) of their populations. We find that Belarus and Russian federation are the two countries with the unhealthiest NCD-related lifestyle. With the exception of Canada, the first twenty populations more exposed to the main NCDs preventable risk factors all live in European countries, and mainly in countries of Eastern Europe. Overall, the UBI tends to increase along with the level of human development. In medium, high and very high HDI countries, however, the same level of human development may be associated with very different kinds of NCD-related lifestyles. Finally, economic growth may push populations toward either more unhealthy or healthy habits, depending on the countries' level of development; the elasticity of unhealthy habits with respect to income per capita is positive (but less than one: on average 0.6) until $30,000, decreases as income rises, and becomes negative (around -0.3) in very high income countries. PMID:26512717

  5. Unhealthy Behaviours: An International Comparison

    PubMed Central

    Ferretti, Fabrizio

    2015-01-01

    In the current global economy, chronic non-communicable diseases (NCDs) have become the leading cause of death and a major health concern for both developed and developing countries. Among other factors, the worldwide spread of NCDs is driven by the globalisation of unhealthy habits. The purpose of this paper is to develop a simple statistic to measure, at the national level, the average population’s exposure to the main NCDs modifiable risk factors. The approach and methodology followed by the United Nations Development Programme to compute the Human Development Index (HDI) is applied to four basic indicators of NCD-related preventable risk factors (alcohol consumption, excess caloric intake, non-balanced diet and tobacco use) in 112 countries worldwide in 2012–14. We obtain a summary composite index, which we call the Unhealthy Behaviour Index (UBI), which ranks countries by the average level of the unhealthy habits (drinking, eating and smoking) of their populations. We find that Belarus and Russian federation are the two countries with the unhealthiest NCD-related lifestyle. With the exception of Canada, the first twenty populations more exposed to the main NCDs preventable risk factors all live in European countries, and mainly in countries of Eastern Europe. Overall, the UBI tends to increase along with the level of human development. In medium, high and very high HDI countries, however, the same level of human development may be associated with very different kinds of NCD-related lifestyles. Finally, economic growth may push populations toward either more unhealthy or healthy habits, depending on the countries’ level of development; the elasticity of unhealthy habits with respect to income per capita is positive (but less than one: on average 0.6) until $30,000, decreases as income rises, and becomes negative (around -0.3) in very high income countries. PMID:26512717

  6. Unhealthy Behaviours: An International Comparison.

    PubMed

    Ferretti, Fabrizio

    2015-01-01

    In the current global economy, chronic non-communicable diseases (NCDs) have become the leading cause of death and a major health concern for both developed and developing countries. Among other factors, the worldwide spread of NCDs is driven by the globalisation of unhealthy habits. The purpose of this paper is to develop a simple statistic to measure, at the national level, the average population's exposure to the main NCDs modifiable risk factors. The approach and methodology followed by the United Nations Development Programme to compute the Human Development Index (HDI) is applied to four basic indicators of NCD-related preventable risk factors (alcohol consumption, excess caloric intake, non-balanced diet and tobacco use) in 112 countries worldwide in 2012-14. We obtain a summary composite index, which we call the Unhealthy Behaviour Index (UBI), which ranks countries by the average level of the unhealthy habits (drinking, eating and smoking) of their populations. We find that Belarus and Russian federation are the two countries with the unhealthiest NCD-related lifestyle. With the exception of Canada, the first twenty populations more exposed to the main NCDs preventable risk factors all live in European countries, and mainly in countries of Eastern Europe. Overall, the UBI tends to increase along with the level of human development. In medium, high and very high HDI countries, however, the same level of human development may be associated with very different kinds of NCD-related lifestyles. Finally, economic growth may push populations toward either more unhealthy or healthy habits, depending on the countries' level of development; the elasticity of unhealthy habits with respect to income per capita is positive (but less than one: on average 0.6) until $30,000, decreases as income rises, and becomes negative (around -0.3) in very high income countries.

  7. On the nonlinear anelastic behaviour of AHSS

    NASA Astrophysics Data System (ADS)

    Torkabadi, A.; Meinders, V. T.; van den Boogaard, A. H.

    2016-08-01

    It has been widely observed that below the yield stress the loading/unloading stress-strain curves of plastically deformed metals are in fact not linear but slightly curved, showing a hysteresis behaviour during unloading/reloading cycles. In addition to the purely elastic strain, extra dislocation based micro-mechanisms are contributing to the reversible strain of the material which results in the nonlinear unloading/reloading behaviour. This extra reversible strain is the so called anelastic strain. As a result, the springback will be larger than that predicted by FEM considering only the recovery of the elastic strain. In this work the physics behind the anelastic behaviour is discussed and experimental results for a dual phase steel are demonstrated. Based on the physics of the phenomenon a model for anelastic behaviour is presented that can fit the experimental results with a good accuracy.

  8. Social information influences trust behaviour in adolescents.

    PubMed

    Lee, Nikki C; Jolles, Jelle; Krabbendam, Lydia

    2016-01-01

    Trust plays an integral role in daily interactions within adolescents' social environment. Using a trust game paradigm, this study investigated the modulating influence of social information about three interaction partners on trust behaviour in adolescents aged 12-18 (N = 845). After receiving information about their interaction partners prior to the task, participants were most likely to share with a 'good' partner and rate this partner as most trustworthy. Over the course of the task all interaction partners showed similar levels of trustworthy behaviour, but overall participants continued to trust and view the good partner as more trustworthy than 'bad' and 'neutral' partners throughout the game. However, with age the ability to overcome prior social information and adapt trust behaviour improved: middle and late adolescents showed a larger decrease in trust of the good partner than early adolescents, and late adolescents were more likely to reward trustworthy behaviour from the negative partner.

  9. Perceived uncivil behaviour in Indonesian nursing education.

    PubMed

    Eka, Ni Gusti Ayu; Chambers, Derek; Narayanasamy, Aru

    2016-09-01

    Uncivil behaviour is a phenomenon that has attracted a growing number of investigations, particularly in Western based nurse education. Unlike the West, uncivil behaviour is a relatively new field of study to Indonesia. However, with the incidence of incivility becoming a growing problem within Indonesian nurse education it is one that warrants investigation. This study investigated; the construct of uncivil behaviour and how it is perceived by students and faculty within the Indonesia context. The impact that socio economic status may play in its manifestation is also explored. The study was conducted in two faculties of nursing in the west of Indonesia. Findings suggest that religion is strongly implicated in the way that uncivil behaviour is perceived.

  10. Data Fusion for Driver Behaviour Analysis

    PubMed Central

    Carmona, Juan; García, Fernando; Martín, David; de la Escalera, Arturo; Armingol, José María

    2015-01-01

    A driver behaviour analysis tool is presented. The proposal offers a novel contribution based on low-cost hardware and advanced software capabilities based on data fusion. The device takes advantage of the information provided by the in-vehicle sensors using Controller Area Network Bus (CAN-BUS), an Inertial Measurement Unit (IMU) and a GPS. By fusing this information, the system can infer the behaviour of the driver, providing aggressive behaviour detection. By means of accurate GPS-based localization, the system is able to add context information, such as digital map information, speed limits, etc. Several parameters and signals are taken into account, both in the temporal and frequency domains, to provide real time behaviour detection. The system was tested in urban, interurban and highways scenarios. PMID:26473875

  11. Data fusion for driver behaviour analysis.

    PubMed

    Carmona, Juan; García, Fernando; Martín, David; Escalera, Arturo de la; Armingol, José María

    2015-10-14

    A driver behaviour analysis tool is presented. The proposal offers a novel contribution based on low-cost hardware and advanced software capabilities based on data fusion. The device takes advantage of the information provided by the in-vehicle sensors using Controller Area Network Bus (CAN-BUS), an Inertial Measurement Unit (IMU) and a GPS. By fusing this information, the system can infer the behaviour of the driver, providing aggressive behaviour detection. By means of accurate GPS-based localization, the system is able to add context information, such as digital map information, speed limits, etc. Several parameters and signals are taken into account, both in the temporal and frequency domains, to provide real time behaviour detection. The system was tested in urban, interurban and highways scenarios.

  12. Social information influences trust behaviour in adolescents.

    PubMed

    Lee, Nikki C; Jolles, Jelle; Krabbendam, Lydia

    2016-01-01

    Trust plays an integral role in daily interactions within adolescents' social environment. Using a trust game paradigm, this study investigated the modulating influence of social information about three interaction partners on trust behaviour in adolescents aged 12-18 (N = 845). After receiving information about their interaction partners prior to the task, participants were most likely to share with a 'good' partner and rate this partner as most trustworthy. Over the course of the task all interaction partners showed similar levels of trustworthy behaviour, but overall participants continued to trust and view the good partner as more trustworthy than 'bad' and 'neutral' partners throughout the game. However, with age the ability to overcome prior social information and adapt trust behaviour improved: middle and late adolescents showed a larger decrease in trust of the good partner than early adolescents, and late adolescents were more likely to reward trustworthy behaviour from the negative partner. PMID:26599529

  13. Data fusion for driver behaviour analysis.

    PubMed

    Carmona, Juan; García, Fernando; Martín, David; Escalera, Arturo de la; Armingol, José María

    2015-01-01

    A driver behaviour analysis tool is presented. The proposal offers a novel contribution based on low-cost hardware and advanced software capabilities based on data fusion. The device takes advantage of the information provided by the in-vehicle sensors using Controller Area Network Bus (CAN-BUS), an Inertial Measurement Unit (IMU) and a GPS. By fusing this information, the system can infer the behaviour of the driver, providing aggressive behaviour detection. By means of accurate GPS-based localization, the system is able to add context information, such as digital map information, speed limits, etc. Several parameters and signals are taken into account, both in the temporal and frequency domains, to provide real time behaviour detection. The system was tested in urban, interurban and highways scenarios. PMID:26473875

  14. Perceived uncivil behaviour in Indonesian nursing education.

    PubMed

    Eka, Ni Gusti Ayu; Chambers, Derek; Narayanasamy, Aru

    2016-09-01

    Uncivil behaviour is a phenomenon that has attracted a growing number of investigations, particularly in Western based nurse education. Unlike the West, uncivil behaviour is a relatively new field of study to Indonesia. However, with the incidence of incivility becoming a growing problem within Indonesian nurse education it is one that warrants investigation. This study investigated; the construct of uncivil behaviour and how it is perceived by students and faculty within the Indonesia context. The impact that socio economic status may play in its manifestation is also explored. The study was conducted in two faculties of nursing in the west of Indonesia. Findings suggest that religion is strongly implicated in the way that uncivil behaviour is perceived. PMID:27543855

  15. Using the theory of planned behaviour to predict observed driving behaviour.

    PubMed

    Elliott, Mark A; Armitage, Christopher J; Baughan, Christopher J

    2007-03-01

    The ability of psychosocial variables to predict driver behaviour was tested using the theory of planned behaviour (TPB; I. Ajzen, 1985) as a theoretical framework. At Time 1, participants (N=150) completed questionnaire measures of TPB variables. 1 week later, participants' behaviour was assessed using both self-reports and observations of driving speed derived from a high-fidelity driving simulator. Multiple regression analyses demonstrated that: (a) the TPB was a strong predictor of drivers' intentions and self-reported speeding behaviour, and (b) intention was the sole predictor of observed speeding behaviour. Standard and repeated events survival analyses showed that intention also predicted the maintenance of drivers' compliance with speed limits. The discussion focuses on the TPB's relationships with observed and self-reported behaviour, and the implications for designing interventions. PMID:17355719

  16. Sexual behaviour: rapid speciation in an arthropod.

    PubMed

    Mendelson, Tamra C; Shaw, Kerry L

    2005-01-27

    Theory predicts that sexual behaviour in animals can evolve rapidly, accelerating the rate of species formation. Here we estimate the rate of speciation in Laupala, a group of forest-dwelling Hawaiian crickets that is characterized primarily through differences in male courtship song. We find that Laupala has the highest rate of speciation so far recorded in arthropods, supporting the idea that divergence in courtship or sexual behaviour drives rapid speciation in animals.

  17. Solvent extraction behaviour of thiocyanic acid.

    PubMed

    Jurriaanse, A; Kemp, D M

    1968-11-01

    The solvent extraction behaviour of thiocyanic acid with isobutyl methyl ketone and xylene as solvents is described. In the ketone system the thiocyanic acid is solvated in the organic phase to give a complex with a proposed composition of HSCN. 2IBMK. Deviations from ideal behaviour, which can be attributed to variations in the activity coefficient of the acid in the aqueous phase, are shown.

  18. From circuits to behaviour in the amygdala.

    PubMed

    Janak, Patricia H; Tye, Kay M

    2015-01-15

    The amygdala has long been associated with emotion and motivation, playing an essential part in processing both fearful and rewarding environmental stimuli. How can a single structure be crucial for such different functions? With recent technological advances that allow for causal investigations of specific neural circuit elements, we can now begin to map the complex anatomical connections of the amygdala onto behavioural function. Understanding how the amygdala contributes to a wide array of behaviours requires the study of distinct amygdala circuits. PMID:25592533

  19. From circuits to behaviour in the amygdala

    PubMed Central

    Janak, Patricia H.; Tye, Kay M.

    2015-01-01

    The amygdala has long been associated with emotion and motivation, playing an essential part in processing both fearful and rewarding environmental stimuli. How can a single structure be crucial for such different functions? With recent technological advances that allow for causal investigations of specific neural circuit elements, we can now begin to map the complex anatomical connections of the amygdala onto behavioural function. Understanding how the amygdala contributes to a wide array of behaviours requires the study of distinct amygdala circuits. PMID:25592533

  20. The behavioural ecology of climbing plants

    PubMed Central

    Gianoli, Ernesto

    2015-01-01

    Climbing plants require an external support to grow vertically and enhance light acquisition. Vines that find a suitable support have greater performance and fitness than those that remain prostrate. Therefore, the location of a suitable support is a key process in the life history of climbing plants. Numerous studies on climbing plant behaviour have elucidated mechanistic details of support searching and attachment. Far fewer studies have addressed the ecological significance of support-finding behaviour and the factors that affect it. Without this knowledge, little progress can be made in the understanding of the evolution of support-finding behaviour in climbers. Here I review studies addressing ecological causes and consequences of support finding and use by climbing plants. I also propose the use of behavioural ecology theoretical frameworks to study climbing plant behaviour. I show how host tree attributes may determine the probability of successful colonization for the different types of climbers, and examine the evidence of environmental and genetic control of circumnutation behaviour and phenotypic responses to support availability. Cases of oriented vine growth towards supports are highlighted. I discuss functional responses of vines to the interplay between herbivory and support availability under different abiotic environments, illustrating with one study case how results comply with a theoretical framework of behavioural ecology originally conceived for animals. I conclude stressing that climbing plants are suitable study subjects for the application of behavioural–ecological theory. Further research under this framework should aim at characterizing the different stages of the support-finding process in terms of their fit with the different climbing modes and environmental settings. In particular, cost–benefit analysis of climbing plant behaviour should be helpful to infer the selective pressures that have operated to shape current climber

  1. Couple Reports of the Perceived Influences of a College Human Sexuality Course: An Exploratory Study

    ERIC Educational Resources Information Center

    Henry, Dayna S.

    2013-01-01

    Research on the effects of college sexuality education has been largely quantitative in nature and has focused on changes in individual attitudes, behaviours and knowledge. This study sought to explore, qualitatively, the influences of enrolment in a human sexuality course on relationships. Eight couples from an undergraduate human sexuality…

  2. Matrix Solution of Coupled Differential Equations and Looped Car Following Models

    ERIC Educational Resources Information Center

    McCartney, Mark

    2008-01-01

    A simple mathematical model for the behaviour of how vehicles follow each other along a looped stretch of road is described. The resulting coupled first order differential equations are solved using appropriate matrix techniques and the physical significance of the model is discussed. A number possible classroom exercises are suggested to help…

  3. Behavioural addiction-A rising tide?

    PubMed

    Chamberlain, Samuel R; Lochner, Christine; Stein, Dan J; Goudriaan, Anna E; van Holst, Ruth Janke; Zohar, Joseph; Grant, Jon E

    2016-05-01

    The term 'addiction' was traditionally used in relation to centrally active substances, such as cocaine, alcohol, or nicotine. Addiction is not a unitary construct but rather incorporates a number of features, such as repetitive engagement in behaviours that are rewarding (at least initially), loss of control (spiralling engagement over time), persistence despite untoward functional consequences, and physical dependence (evidenced by withdrawal symptoms when intake of the substance diminishes). It has been suggested that certain psychiatric disorders characterized by maladaptive, repetitive behaviours share parallels with substance addiction and therefore represent 'behavioural addictions'. This perspective has influenced the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), which now has a category 'Substance Related and Addictive Disorders', including gambling disorder. Could other disorders characterised by repetitive behaviours, besides gambling disorder, also be considered 'addictions'? Potential examples include kleptomania, compulsive sexual behaviour, 'Internet addiction', trichotillomania (hair pulling disorder), and skin-picking disorder. This paper seeks to define what is meant by 'behavioural addiction', and critically considers the evidence for and against this conceptualisation in respect of the above conditions, from perspectives of aetiology, phenomenology, co-morbidity, neurobiology, and treatment. Research in this area has important implications for future diagnostic classification systems, neurobiological models, and novel treatment directions. PMID:26585600

  4. Behavioural addiction-A rising tide?

    PubMed

    Chamberlain, Samuel R; Lochner, Christine; Stein, Dan J; Goudriaan, Anna E; van Holst, Ruth Janke; Zohar, Joseph; Grant, Jon E

    2016-05-01

    The term 'addiction' was traditionally used in relation to centrally active substances, such as cocaine, alcohol, or nicotine. Addiction is not a unitary construct but rather incorporates a number of features, such as repetitive engagement in behaviours that are rewarding (at least initially), loss of control (spiralling engagement over time), persistence despite untoward functional consequences, and physical dependence (evidenced by withdrawal symptoms when intake of the substance diminishes). It has been suggested that certain psychiatric disorders characterized by maladaptive, repetitive behaviours share parallels with substance addiction and therefore represent 'behavioural addictions'. This perspective has influenced the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), which now has a category 'Substance Related and Addictive Disorders', including gambling disorder. Could other disorders characterised by repetitive behaviours, besides gambling disorder, also be considered 'addictions'? Potential examples include kleptomania, compulsive sexual behaviour, 'Internet addiction', trichotillomania (hair pulling disorder), and skin-picking disorder. This paper seeks to define what is meant by 'behavioural addiction', and critically considers the evidence for and against this conceptualisation in respect of the above conditions, from perspectives of aetiology, phenomenology, co-morbidity, neurobiology, and treatment. Research in this area has important implications for future diagnostic classification systems, neurobiological models, and novel treatment directions.

  5. Mechanosensory interactions drive collective behaviour in Drosophila.

    PubMed

    Ramdya, Pavan; Lichocki, Pawel; Cruchet, Steeve; Frisch, Lukas; Tse, Winnie; Floreano, Dario; Benton, Richard

    2015-03-12

    Collective behaviour enhances environmental sensing and decision-making in groups of animals. Experimental and theoretical investigations of schooling fish, flocking birds and human crowds have demonstrated that simple interactions between individuals can explain emergent group dynamics. These findings indicate the existence of neural circuits that support distributed behaviours, but the molecular and cellular identities of relevant sensory pathways are unknown. Here we show that Drosophila melanogaster exhibits collective responses to an aversive odour: individual flies weakly avoid the stimulus, but groups show enhanced escape reactions. Using high-resolution behavioural tracking, computational simulations, genetic perturbations, neural silencing and optogenetic activation we demonstrate that this collective odour avoidance arises from cascades of appendage touch interactions between pairs of flies. Inter-fly touch sensing and collective behaviour require the activity of distal leg mechanosensory sensilla neurons and the mechanosensory channel NOMPC. Remarkably, through these inter-fly encounters, wild-type flies can elicit avoidance behaviour in mutant animals that cannot sense the odour--a basic form of communication. Our data highlight the unexpected importance of social context in the sensory responses of a solitary species and open the door to a neural-circuit-level understanding of collective behaviour in animal groups. PMID:25533959

  6. Intergenerational transmission of reproductive behaviour in Botswana.

    PubMed

    Langeni, Tabitha T

    2011-01-01

    The purpose of this study was to investigate intergenerational transmission of reproductive behaviour in Botswana. The major source of data was the 2001 Botswana AIDS Impact Survey where a nationally representative random sample of men and women aged 10-64 years was selected using a stratified two-stage probability sample design. Covariates in the analysis include age, education, marital status, religion, age at first birth, residence, duration at residence and contraceptive use. The main analytical technique is linear regression. The results indicate that the reproductive behaviour of older generations has a significantly positive influence on the reproductive behaviour of the subsequent generation, but does not affect the subsequent generation homogeneously. The effect appeared much stronger for women who initiated childbearing at an older age, for women who had never been to school, and for the cohort aged 50-59 years. These findings suggest that number of siblings, as a reproductive behaviour determinant, may very well have confounded previous reproductive behaviour analyses in Botswana. The study draws attention to the importance of the effect of origin family size in determining reproductive behaviour outcomes in Botswana.

  7. Model development for household waste prevention behaviour.

    PubMed

    Bortoleto, Ana Paula; Kurisu, Kiyo H; Hanaki, Keisuke

    2012-12-01

    Understanding waste prevention behaviour (WPB) could enable local governments and decision makers to design more-effective policies for reducing the amount of waste that is generated. By merging well-known attitude-behaviour theories with elements from wider models from environmental psychology, an extensive cognitive framework that provides new and valuable insights is developed for understanding the involvement of individuals in waste prevention. The results confirm the usefulness of the theory of planned behaviour and of Schwartz's altruistic behaviour model as bases for modelling participation in waste prevention. A more elaborate integrated model of prevention was shown to be necessary for the complete analysis of attitudinal aspects associated with waste prevention. A postal survey of 158 respondents provided empirical support for eight of 12 hypotheses. The proposed structural equation indicates that personal norms and perceived behaviour control are the main predictors and that, unlike the case of recycling, subjective norms have a weak influence on WPB. It also suggests that, since social norms have not presented a direct influence, WPB is likely to be influenced by a concern for the environment and the community as well by perceptions of moral obligation and inconvenience. Results also proved that recycling and waste prevention represent different dimensions of waste management behaviour requiring particular approaches to increase individuals' engagement in future policies.

  8. Can the theory of planned behaviour predict the physical activity behaviour of individuals?

    PubMed

    Hobbs, Nicola; Dixon, Diane; Johnston, Marie; Howie, Kate

    2013-01-01

    The theory of planned behaviour (TPB) can identify cognitions that predict differences in behaviour between individuals. However, it is not clear whether the TPB can predict the behaviour of an individual person. This study employs a series of n-of-1 studies and time series analyses to examine the ability of the TPB to predict physical activity (PA) behaviours of six individuals. Six n-of-1 studies were conducted, in which TPB cognitions and up to three PA behaviours (walking, gym workout and a personally defined PA) were measured twice daily for six weeks. Walking was measured by pedometer step count, gym attendance by self-report with objective validation of gym entry and the personally defined PA behaviour by self-report. Intra-individual variability in TPB cognitions and PA behaviour was observed in all participants. The TPB showed variable predictive utility within individuals and across behaviours. The TPB predicted at least one PA behaviour for five participants but had no predictive utility for one participant. Thus, n-of-1 designs and time series analyses can be used to test theory in an individual.

  9. Can the theory of planned behaviour predict the physical activity behaviour of individuals?

    PubMed

    Hobbs, Nicola; Dixon, Diane; Johnston, Marie; Howie, Kate

    2013-01-01

    The theory of planned behaviour (TPB) can identify cognitions that predict differences in behaviour between individuals. However, it is not clear whether the TPB can predict the behaviour of an individual person. This study employs a series of n-of-1 studies and time series analyses to examine the ability of the TPB to predict physical activity (PA) behaviours of six individuals. Six n-of-1 studies were conducted, in which TPB cognitions and up to three PA behaviours (walking, gym workout and a personally defined PA) were measured twice daily for six weeks. Walking was measured by pedometer step count, gym attendance by self-report with objective validation of gym entry and the personally defined PA behaviour by self-report. Intra-individual variability in TPB cognitions and PA behaviour was observed in all participants. The TPB showed variable predictive utility within individuals and across behaviours. The TPB predicted at least one PA behaviour for five participants but had no predictive utility for one participant. Thus, n-of-1 designs and time series analyses can be used to test theory in an individual. PMID:22943555

  10. New coupled quintessence cosmology

    SciTech Connect

    Jesus, J. F.; Santos, R. C.; Lima, J. A. S.; Alcaniz, J. S.

    2008-09-15

    A component of dark energy has been recently proposed to explain the current acceleration of the Universe. Unless some unknown symmetry in Nature prevents or suppresses it, such a field may interact with the pressureless component of dark matter, giving rise to the so-called models of coupled quintessence. In this paper we propose a new cosmological scenario where radiation and baryons are conserved, while the dark energy component is decaying into cold dark matter. The dilution of cold dark matter particles, attenuated with respect to the usual a{sup -3} scaling due to the interacting process, is characterized by a positive parameter {epsilon}, whereas the dark energy satisfies the equation of state p{sub x}={omega}{rho}{sub x} ({omega}<0). We carry out a joint statistical analysis involving recent observations from type Ia supernovae, baryon acoustic oscillation peak, and cosmic microwave background shift parameter to check the observational viability of the coupled quintessence scenario here proposed.

  11. Anomalous gauge boson couplings

    SciTech Connect

    Barklow, T.; Rizzo, T.; Baur, U.

    1997-01-13

    The measurement of anomalous gauge boson self couplings is reviewed for a variety of present and planned accelerators. Sensitivities are compared for these accelerators using models based on the effective Lagrangian approach. The sensitivities described here are for measurement of {open_quotes}generic{close_quotes} parameters {kappa}{sub V}, {lambda}{sub V}, etc., defined in the text. Pre-LHC measurements will not probe these coupling parameters to precision better than O(10{sup -1}). The LHC should be sensitive to better than O(10{sup -2}), while a future NLC should achieve sensitivity of O(10{sup -3}) to O(10{sup -4}) for center of mass energies ranging from 0.5 to 1.5 TeV.

  12. Coupled wellbore erosion and stability analysis

    NASA Astrophysics Data System (ADS)

    Stavropoulou, M.; Papanastasiou, P.; Vardoulakis, I.

    1998-09-01

    This paper extends earlier work on sand erosion and presents an attempt to couple sand erosion to mechanical damage of rock around a wellbore. Porosity which evolves in time and space as surface erosion progresses, is chosen as the coupling parameter. Both rock elasticity and strength (cohesion) are assumed to depend on porosity in such a way that the material becomes weaker with increasing porosity. The mathematical model, consists of erosion equations, mixture flow equations and stress equilibrium equations, is solved numerically by Galerkin finite element method. Numerical results suggest that erosion, resulting in sand production, is high close to the free surface. Erosion is accompained by changes in porosity and a significant permeability increase. Erosion in the vicinity of the wellbore induces alterations in the mechanical behaviour of the medium. Weakening of rock stiffness leads to severe alteration of both effective stresses and pore pressure near the cavity. Since cohesion decreases with increasing porosity, one can also identify the time instant at which rock mechanical failure starts.

  13. Magnetic coupling device

    DOEpatents

    Nance, Thomas A.

    2009-08-18

    A quick connect/disconnect coupling apparatus is provided in which a base member is engaged by a locking housing through a series of interengagement pins. The pins maintain the shaft in a locked position. Upon exposure to an appropriately positioned magnetic field, pins are removed a sufficient distance such that the shaft may be withdrawn from the locking housing. The ability to lock and unlock the connector assembly requires no additional tools or parts apart from a magnetic key.

  14. COAXIAL TUBE COUPLING

    DOEpatents

    Niemoth, H.R.

    1963-02-26

    BS>This patent shows a device for quickly coupling coaxial tubes in metal-to-metal fashion, so as to be suitable for use in a nuclear reactor. A threaded coliar urges a tapered metal extension on the outer coaxial tube into a tapered seat in the device and simultaneously exerts pressure through a coaxial helical spring so that a similar extension on the inner tube seats in a similar seat near the other end. (AEC)

  15. Quick torque coupling

    DOEpatents

    Luft, Peter A.

    2009-05-12

    A coupling for mechanically connecting modular tubular struts of a positioning apparatus or space frame, comprising a pair of toothed rings (10, 12) attached to separate strut members (16), the teeth (18, 20) of the primary rings (10, 12) mechanically interlocking in both an axial and circumferential manner, and a third part comprising a sliding, toothed collar (14) the teeth (22) of which interlock the teeth (18, 20) of the primary rings (10, 12), preventing them from disengaging, and completely locking the assembly together. A secondary mechanism provides a nesting force for the collar, and/or retains it. The coupling is self-contained and requires no external tools for installation, and can be assembled with gloved hands in demanding environments. No gauging or measured torque is required for assembly. The assembly can easily be visually inspected to determine a "go" or "no-go" status. The coupling is compact and relatively light-weight. Because of it's triply interlocking teeth, the connection is rigid. The connection does not primarily rely on clamps, springs or friction based fasteners, and is therefore reliable in fail-safe applications.

  16. Effects of Emergence Time and Early Social Rearing Environment on Behaviour of Atlantic Salmon: Consequences for Juvenile Fitness and Smolt Migration

    PubMed Central

    Larsen, Martin H.; Johnsson, Jörgen I.; Winberg, Svante; Wilson, Alexander D. M.; Hammenstig, David; Thörnqvist, Per-Ove; Midwood, Jonathan D.; Aarestrup, Kim; Höglund, Erik

    2015-01-01

    Consistent individual differences in behaviour have been well documented in a variety of animal taxa, but surprisingly little is known about the fitness and life-history consequences of such individual variation. In wild salmonids, the timing of fry emergence from gravel spawning nests has been suggested to be coupled with individual behavioural traits. Here, we further investigate the link between timing of spawning nest emergence and behaviour of Atlantic salmon (Salmo salar), test effects of social rearing environment on behavioural traits in fish with different emergence times, and assess whether behavioural traits measured in the laboratory predict growth, survival, and migration status in the wild. Atlantic salmon fry were sorted with respect to emergence time from artificial spawning nest into three groups: early, intermediate, and late. These emergence groups were hatchery-reared separately or in co-culture for four months to test effects of social rearing environment on behavioural traits. Twenty fish from each of the six treatment groups were then subjected to three individual-based behavioural tests: basal locomotor activity, boldness, and escape response. Following behavioural characterization, the fish were released into a near-natural experimental stream. Results showed differences in escape behaviour between emergence groups in a net restraining test, but the social rearing environment did not affect individual behavioural expression. Emergence time and social environment had no significant effects on survival, growth, and migration status in the stream, although migration propensity was 1.4 to 1.9 times higher for early emerging individuals that were reared separately. In addition, despite individuals showing considerable variation in behaviour across treatment groups, this was not translated into differences in growth, survival, and migration status. Hence, our study adds to the view that fitness (i.e., growth and survival) and life

  17. Dynamic coupling of plasmonic resonators

    NASA Astrophysics Data System (ADS)

    Lee, Suyeon; Park, Q.-Han

    2016-02-01

    We clarify the nature of dynamic coupling in plasmonic resonators and determine the dynamic coupling coefficient using a simple analytic model. We show that plasmonic resonators, such as subwavelength holes in a metal film which can be treated as bound charge oscillators, couple to each other through the retarded interaction of oscillating screened charges. Our dynamic coupling model offers, for the first time, a quantitative analytic description of the fundamental symmetric and anti-symmetric modes of coupled resonators which agrees with experimental results. Our model also reveals that plasmonic electromagnetically induced transparency arises in any coupled resonators of slightly unequal lengths, as confirmed by a rigorous numerical calculation and experiments.

  18. Dynamic coupling of plasmonic resonators

    PubMed Central

    Lee, Suyeon; Park, Q-Han

    2016-01-01

    We clarify the nature of dynamic coupling in plasmonic resonators and determine the dynamic coupling coefficient using a simple analytic model. We show that plasmonic resonators, such as subwavelength holes in a metal film which can be treated as bound charge oscillators, couple to each other through the retarded interaction of oscillating screened charges. Our dynamic coupling model offers, for the first time, a quantitative analytic description of the fundamental symmetric and anti-symmetric modes of coupled resonators which agrees with experimental results. Our model also reveals that plasmonic electromagnetically induced transparency arises in any coupled resonators of slightly unequal lengths, as confirmed by a rigorous numerical calculation and experiments. PMID:26911786

  19. Anti-Social Behaviour: Children, Schools and Parents

    ERIC Educational Resources Information Center

    Riley, Dan

    2007-01-01

    Under Prime Minister Tony Blair's New Labour government, increased criminalisation of previously non-criminal behaviour, anti-social behaviour and greater accountability of children and parents for their behaviour were evident. The article provides an overview of anti-social behaviour legislation and the implications for children, schools and…

  20. Patterns of Sedentary Behaviours in Irish Female Adolescents

    ERIC Educational Resources Information Center

    Regan, Aine; Heary, Caroline

    2013-01-01

    Engagement in excessive sedentary behaviour represents a health risk for adolescents. The current study aimed to investigate patterns of sedentary behaviour amongst Irish female adolescents aged between 15 and 19 years old. 314 adolescents completed a questionnaire on their sedentary behaviour habits, health behaviours (physical activity, smoking,…

  1. Aggressive Behaviour and Its Prevalence within Five Typologies

    ERIC Educational Resources Information Center

    Crotty, Gerard; Doody, Owen; Lyons, Rosemary

    2014-01-01

    Crucial to understanding an individual, presenting with intellectual disability and the management of their challenging behaviours, is the knowledge of the types of those specific behaviours. The term aggressive behaviour is a universal term that embraces many aspects of behaviour that vary in terms of severity, frequency and seriousness for the…

  2. Behaviour of emerging contaminants in sewage sludge after anaerobic digestion.

    PubMed

    Boix, C; Ibáñez, M; Fabregat-Safont, D; Morales, E; Pastor, L; Sancho, J V; Sánchez-Ramírez, J E; Hernández, F

    2016-11-01

    Nowadays, there is an increasing concern over the presence of contaminants in the aquatic environment, where they can be introduced from wastewater after their incomplete removal in the treatment plants. In this work, degradation of selected emerging pollutants in the aqueous and solid phases of sewage sludge has been investigated after anaerobic digestion using two different digesters: mesophilic and thermophilic. Initially, sludge samples were screened by ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS) for identification of emerging contaminants in the samples. In a second step, a target quantitative method based on LC coupled to tandem MS was applied for selected pollutants identified in the previous screening. The behaviour of the compounds under anaerobic conditions was studied estimating the degradation efficiency and distribution of compounds between both sludge phases. Irbesartan and benzoylecgonine seemed to be notably degraded in both phases of the sludge. Venlafaxine showed a significant concentration decrease in the aqueous phase in parallel to an increase in the solid phase. The majority of the compounds showed an increase of their concentrations in both phases after the digestion. Concentrations in the solid phase were commonly higher than in the aqueous for most contaminants, indicating that they were preferentially adsorbed onto the solid particles. PMID:27543679

  3. The QCD running coupling

    NASA Astrophysics Data System (ADS)

    Deur, Alexandre; Brodsky, Stanley J.; de Téramond, Guy F.

    2016-09-01

    We review the present theoretical and empirical knowledge for αs, the fundamental coupling underlying the interactions of quarks and gluons in Quantum Chromodynamics (QCD). The dependence of αs(Q2) on momentum transfer Q encodes the underlying dynamics of hadron physics-from color confinement in the infrared domain to asymptotic freedom at short distances. We review constraints on αs(Q2) at high Q2, as predicted by perturbative QCD, and its analytic behavior at small Q2, based on models of nonperturbative dynamics. In the introductory part of this review, we explain the phenomenological meaning of the coupling, the reason for its running, and the challenges facing a complete understanding of its analytic behavior in the infrared domain. In the second, more technical, part of the review, we discuss the behavior of αs(Q2) in the high momentum transfer domain of QCD. We review how αs is defined, including its renormalization scheme dependence, the definition of its renormalization scale, the utility of effective charges, as well as "Commensurate Scale Relations" which connect the various definitions of the QCD coupling without renormalization-scale ambiguity. We also report recent significant measurements and advanced theoretical analyses which have led to precise QCD predictions at high energy. As an example of an important optimization procedure, we discuss the "Principle of Maximum Conformality", which enhances QCD's predictive power by removing the dependence of the predictions for physical observables on the choice of theoretical conventions such as the renormalization scheme. In the last part of the review, we discuss the challenge of understanding the analytic behavior αs(Q2) in the low momentum transfer domain. We survey various theoretical models for the nonperturbative strongly coupled regime, such as the light-front holographic approach to QCD. This new framework predicts the form of the quark-confinement potential underlying hadron spectroscopy and

  4. Coupling multi-physics models to cardiac mechanics.

    PubMed

    Nordsletten, D A; Niederer, S A; Nash, M P; Hunter, P J; Smith, N P

    2011-01-01

    We outline and review the mathematical framework for representing mechanical deformation and contraction of the cardiac ventricles, and how this behaviour integrates with other processes crucial for understanding and modelling heart function. Building on general conservation principles of space, mass and momentum, we introduce an arbitrary Eulerian-Lagrangian framework governing the behaviour of both fluid and solid components. Exploiting the natural alignment of cardiac mechanical properties with the tissue microstructure, finite deformation measures and myocardial constitutive relations are referred to embedded structural axes. Coupling approaches for solving this large deformation mechanics framework with three dimensional fluid flow, coronary hemodynamics and electrical activation are described. We also discuss the potential of cardiac mechanics modelling for clinical applications.

  5. A sensing array of radically coupled genetic 'biopixels'.

    PubMed

    Prindle, Arthur; Samayoa, Phillip; Razinkov, Ivan; Danino, Tal; Tsimring, Lev S; Hasty, Jeff

    2012-01-01

    Although there has been considerable progress in the development of engineering principles for synthetic biology, a substantial challenge is the construction of robust circuits in a noisy cellular environment. Such an environment leads to considerable intercellular variability in circuit behaviour, which can hinder functionality at the colony level. Here we engineer the synchronization of thousands of oscillating colony 'biopixels' over centimetre-length scales through the use of synergistic intercellular coupling involving quorum sensing within a colony and gas-phase redox signalling between colonies. We use this platform to construct a liquid crystal display (LCD)-like macroscopic clock that can be used to sense arsenic via modulation of the oscillatory period. Given the repertoire of sensing capabilities of bacteria such as Escherichia coli, the ability to coordinate their behaviour over large length scales sets the stage for the construction of low cost genetic biosensors that are capable of detecting heavy metals and pathogens in the field. PMID:22178928

  6. The principles of collective animal behaviour

    PubMed Central

    Sumpter, D.J.T

    2005-01-01

    In recent years, the concept of self-organization has been used to understand collective behaviour of animals. The central tenet of self-organization is that simple repeated interactions between individuals can produce complex adaptive patterns at the level of the group. Inspiration comes from patterns seen in physical systems, such as spiralling chemical waves, which arise without complexity at the level of the individual units of which the system is composed. The suggestion is that biological structures such as termite mounds, ant trail networks and even human crowds can be explained in terms of repeated interactions between the animals and their environment, without invoking individual complexity. Here, I review cases in which the self-organization approach has been successful in explaining collective behaviour of animal groups and societies. Ant pheromone trail networks, aggregation of cockroaches, the applause of opera audiences and the migration of fish schools have all been accurately described in terms of individuals following simple sets of rules. Unlike the simple units composing physical systems, however, animals are themselves complex entities, and other examples of collective behaviour, such as honey bee foraging with its myriad of dance signals and behavioural cues, cannot be fully understood in terms of simple individuals alone. I argue that the key to understanding collective behaviour lies in identifying the principles of the behavioural algorithms followed by individual animals and of how information flows between the animals. These principles, such as positive feedback, response thresholds and individual integrity, are repeatedly observed in very different animal societies. The future of collective behaviour research lies in classifying these principles, establishing the properties they produce at a group level and asking why they have evolved in so many different and distinct natural systems. Ultimately, this research could inform not only our

  7. Using health psychology to help patients: theories of behaviour change.

    PubMed

    Barley, Elizabeth; Lawson, Victoria

    2016-09-01

    Behaviour change theories and related research evidence highlight the complexity of making and sticking to health-related behaviour changes. These theories make explicit factors that influence behaviour change, such as health beliefs, past behaviour, intention, social influences, perceived control and the context of the behaviour. Nurses can use this information to understand why a particular patient may find making recommended health behaviour changes difficult and to determine factors that may help them. This article outlines five well-established theories of behaviour change: the health belief model, the theory of planned behaviour, the stages of change model, self-determination theory, and temporal self-regulation theory. The evidence for interventions that are informed by these theories is then explored and appraised. The extent and quality of evidence varies depending on the type of behaviour and patients targeted, but evidence from randomised controlled trials indicates that interventions informed by theory can result in behaviour change.

  8. Using health psychology to help patients: theories of behaviour change.

    PubMed

    Barley, Elizabeth; Lawson, Victoria

    2016-09-01

    Behaviour change theories and related research evidence highlight the complexity of making and sticking to health-related behaviour changes. These theories make explicit factors that influence behaviour change, such as health beliefs, past behaviour, intention, social influences, perceived control and the context of the behaviour. Nurses can use this information to understand why a particular patient may find making recommended health behaviour changes difficult and to determine factors that may help them. This article outlines five well-established theories of behaviour change: the health belief model, the theory of planned behaviour, the stages of change model, self-determination theory, and temporal self-regulation theory. The evidence for interventions that are informed by these theories is then explored and appraised. The extent and quality of evidence varies depending on the type of behaviour and patients targeted, but evidence from randomised controlled trials indicates that interventions informed by theory can result in behaviour change. PMID:27615529

  9. Experimental procedure for the evaluation of tooth stiffness in spline coupling including angular misalignment

    NASA Astrophysics Data System (ADS)

    Curà, Francesca; Mura, Andrea

    2013-11-01

    Tooth stiffness is a very important parameter in studying both static and dynamic behaviour of spline couplings and gears. Many works concerning tooth stiffness calculation are available in the literature, but experimental results are very rare, above all considering spline couplings. In this work experimental values of spline coupling tooth stiffness have been obtained by means of a special hexapod measuring device. Experimental results have been compared with the corresponding theoretical and numerical ones. Also the effect of angular misalignments between hub and shaft has been investigated in the experimental planning.

  10. Addressing Challenging Behaviour in Children with Down Syndrome: The Use of Applied Behaviour Analysis for Assessment and Intervention

    ERIC Educational Resources Information Center

    Feeley, Kathlee M.; Jones, Emily A.

    2006-01-01

    Children with Down syndrome are at an increased risk for engaging in challenging behaviour that may be part of a behavioural phenotype characteristic of Down syndrome. The methodology of applied behaviour analysis has been demonstrated effective with a wide range of challenging behaviours, across various disabilities. Applications to children with…

  11. Increasing the Teacher Rate of Behaviour Specific Praise and its Effect on a Child with Aggressive Behaviour Problems

    ERIC Educational Resources Information Center

    Moffat, Thecla Kudakwashe

    2011-01-01

    A single subject design was used to investigate the effectiveness of an increase in teacher behaviour-specific praise statements to address anti-social behaviours demonstrated by a student who displays aggressive behaviours. Researchers agree that praise is effective in improving problem behaviours. They also agree that training teachers to use…

  12. Relations between Parenting and Externalizing and Internalizing Problem Behaviour in Early Adolescence: Child Behaviour as Moderator and Predictor

    ERIC Educational Resources Information Center

    Reitz, E.; Dekovic, M.; Meijer, A. M.

    2006-01-01

    In this longitudinal study we investigated relations between parenting and externalizing and internalizing problem behaviour during early adolescence. First, we examined parenting effects on problem behaviour, including child behaviour as a moderator. Second, we examined child behaviour as predictor of parenting, also including moderator effects.…

  13. Trajectories of Antisocial Behaviour towards Siblings Predict Antisocial Behaviour towards Peers

    ERIC Educational Resources Information Center

    Ensor, Rosie; Marks, Alex; Jacobs, Lorna; Hughes, Claire

    2010-01-01

    Background: Young siblings' antisocial behaviour is common yet its impact has received relatively little research attention. Methods: We examined trajectories of antisocial behaviour for a socially diverse sample (n = 99, 58 boys and 41 girls) who were filmed with their older siblings (52 boys and 47 girls) at ages 3 and 6 and with unfamiliar…

  14. Classroom Behaviour and Academic Achievement: How Classroom Behaviour Categories Relate to Gender and Academic Performance

    ERIC Educational Resources Information Center

    Borg, Elin

    2015-01-01

    Latent profile analysis was used to identify different categories of students having different "profiles" using self-reported classroom behaviour. Four categories of students with unique classroom behaviour profiles were identified among secondary school students in Oslo, Norway (n = 1570). Analyses examined how classroom behaviour…

  15. Behavioural Interventions for Self Injurious Behaviour: A Review of Recent Evidence (1998-2008)

    ERIC Educational Resources Information Center

    Prangnell, Simon J.

    2010-01-01

    Estimates suggest that up to one quarter of people who have a severe learning disability engage in self injurious behaviour (SIB). SIB poses serious risks, both to the person's physical health and their quality of life. Behavioural approaches have made a contribution to supporting people who engage in SIB, although the last review of these…

  16. Intervention of Behavioural, Cognitive and Sex on Early Childhood's Aggressive Behaviour

    ERIC Educational Resources Information Center

    Purwati; Japar, Muhammad

    2015-01-01

    This study aims to find out the effect of behavioural intervention, cognitive intervention, and sex intervention toward the aggressive behaviour of early childhood. The study is conducted at two non-formal institutions of Education on Early Childhood in Magelang. This study obtains the data from two experimental groups consisting of 14 early…

  17. Psychosocial Correlates of Dietary Behaviour in Type 2 Diabetic Women, Using a Behaviour Change Theory

    PubMed Central

    Shojaeizadeh, D.; asl, R. Gharaaghaji; Niknami, S.; Khorami, A.

    2014-01-01

    ABSTRACT The study evaluated the efficacy of the Theory of Reasoned Action (TRA), along with self-efficacy to predict dietary behaviour in a group of Iranian women with type 2 diabetes. A sample of 352 diabetic women referred to Khoy Diabetes Clinic, Iran, were selected and given a self-administered survey to assess eating behaviour, using the extended TRA constructs. Bivariate correlations and Enter regression analyses of the extended TRA model were performed with SPSS software. Overall, the proposed model explained 31.6% of variance of behavioural intention and 21.5% of variance of dietary behaviour. Among the model constructs, self-efficacy was the strongest predictor of intentions and dietary practice. In addition to the model variables, visit intervals of patients and source of obtaining information about diabetes from sociodemographic factors were also associated with dietary behaviours of the diabetics. This research has highlighted the relative importance of the extended TRA constructs upon behavioural intention and subsequent behaviour. Therefore, use of the present research model in designing educational interventions to increase adherence to dietary behaviours among diabetic patients was recommended and emphasized. PMID:25076670

  18. Psychosocial correlates of dietary behaviour in type 2 diabetic women, using a behaviour change theory.

    PubMed

    Didarloo, A; Shojaeizadeh, D; Gharaaghaji Asl, R; Niknami, S; Khorami, A

    2014-06-01

    The study evaluated the efficacy of the Theory of Reasoned Action (TRA), along with self-efficacy to predict dietary behaviour in a group of Iranian women with type 2 diabetes. A sample of 352 diabetic women referred to Khoy Diabetes Clinic, Iran, were selected and given a self-administered survey to assess eating behaviour, using the extended TRA constructs. Bivariate correlations and Enter regression analyses of the extended TRA model were performed with SPSS software. Overall, the proposed model explained 31.6% of variance of behavioural intention and 21.5% of variance of dietary behaviour. Among the model constructs, self-efficacy was the strongest predictor of intentions and dietary practice. In addition to the model variables, visit intervals of patients and source of obtaining information about diabetes from sociodemographic factors were also associated with dietary behaviours of the diabetics. This research has highlighted the relative importance of the extended TRA constructs upon behavioural intention and subsequent behaviour. Therefore, use of the present research model in designing educational interventions to increase adherence to dietary behaviours among diabetic patients was recommended and emphasized. PMID:25076670

  19. Cognitive-Behavioural Therapy for Children with Behavioural Difficulties in the Singapore Mainstream School Setting

    ERIC Educational Resources Information Center

    Yeo, Lay See; Choi, Pui Meng

    2011-01-01

    The present study investigated the effectiveness of a cognitive-behavioural therapy (CBT) programme delivered by a school psychologist for children with behavioural difficulties in Singapore elementary school classrooms. It examined the impact of a 12-session, psychoeducational group intervention in helping misbehaving pupils to control their…

  20. Psychosocial correlates of dietary behaviour in type 2 diabetic women, using a behaviour change theory.

    PubMed

    Didarloo, A; Shojaeizadeh, D; Gharaaghaji Asl, R; Niknami, S; Khorami, A

    2014-06-01

    The study evaluated the efficacy of the Theory of Reasoned Action (TRA), along with self-efficacy to predict dietary behaviour in a group of Iranian women with type 2 diabetes. A sample of 352 diabetic women referred to Khoy Diabetes Clinic, Iran, were selected and given a self-administered survey to assess eating behaviour, using the extended TRA constructs. Bivariate correlations and Enter regression analyses of the extended TRA model were performed with SPSS software. Overall, the proposed model explained 31.6% of variance of behavioural intention and 21.5% of variance of dietary behaviour. Among the model constructs, self-efficacy was the strongest predictor of intentions and dietary practice. In addition to the model variables, visit intervals of patients and source of obtaining information about diabetes from sociodemographic factors were also associated with dietary behaviours of the diabetics. This research has highlighted the relative importance of the extended TRA constructs upon behavioural intention and subsequent behaviour. Therefore, use of the present research model in designing educational interventions to increase adherence to dietary behaviours among diabetic patients was recommended and emphasized.

  1. Teacher Stress and Pupil Behaviour Explored through a Rational-Emotive Behaviour Therapy Framework

    ERIC Educational Resources Information Center

    Robertson, Caroline; Dunsmuir, Sandra

    2013-01-01

    Using the psychological framework of rational-emotive behaviour therapy, the principal aim of this study was to establish whether irrational beliefs, self-efficacy or pupil behaviour predicted teacher reports of stress. A secondary aim was to establish whether these variables, in addition to teachers' verbal feedback to pupils in class, predicted…

  2. Teacher Verbal Feedback Directed towards Secondary Pupils with Challenging Behaviour and Its Relationship to Their Behaviour

    ERIC Educational Resources Information Center

    Swinson, J.; Knight, R.

    2007-01-01

    There is a body of evidence that has linked teachers' verbal feedback to pupils with pupil behaviour. In this study teacher verbal behaviour that was directed towards those pupils that the teachers had nominated as being especially difficult to teach was examined. A series of lessons was observed in a secondary school. The quality and quantity of…

  3. Cognitive-Behavioural Treatment for Men with Intellectual Disabilities and Sexually Abusive Behaviour: A Pilot Study

    ERIC Educational Resources Information Center

    Murphy, Glynis; Powell, Simon; Guzman, Ana-Maria; Hays, Sarah-Jane

    2007-01-01

    Background: Cognitive-behaviour therapy (CBT) seems to be becoming the treatment of choice for non-disabled sex offenders. Nevertheless, there have been relatively few evaluations of such treatment for men with intellectual disabilities (ID) and sexually abusive behaviour. Method: A pilot study providing CBT for two groups of men with ID is…

  4. Tracking Optical and Electronic Behaviour of Quantum Contacts in Sub-Nanometre Plasmonic Cavities.

    PubMed

    Sanders, A; Bowman, R W; Baumberg, J J

    2016-01-01

    Plasmonic interactions between two metallic tips are dynamically studied in a supercontinuum dark-field microscope and the transition between coupled and charge-transfer plasmons is directly observed in the sub-nm regime. Simultaneous measurement of the dc current, applied force, and optical scattering as the tips come together is used to determine the effects of conductive pathways within the plasmonic nano-gap. Critical conductances are experimentally identified for the first time, determining the points at which quantum tunnelling and conductive charge transport begin to influence plasmon coupling. These results advance our understanding of the relationship between conduction and plasmonics, and the fundamental quantum mechanical behaviours of plasmonic coupling. PMID:27608825

  5. Tracking Optical and Electronic Behaviour of Quantum Contacts in Sub-Nanometre Plasmonic Cavities

    PubMed Central

    Sanders, A.; Bowman, R. W.; Baumberg, J. J.

    2016-01-01

    Plasmonic interactions between two metallic tips are dynamically studied in a supercontinuum dark-field microscope and the transition between coupled and charge-transfer plasmons is directly observed in the sub-nm regime. Simultaneous measurement of the dc current, applied force, and optical scattering as the tips come together is used to determine the effects of conductive pathways within the plasmonic nano-gap. Critical conductances are experimentally identified for the first time, determining the points at which quantum tunnelling and conductive charge transport begin to influence plasmon coupling. These results advance our understanding of the relationship between conduction and plasmonics, and the fundamental quantum mechanical behaviours of plasmonic coupling. PMID:27608825

  6. Visuomotor behaviours when using a myoelectric prosthesis

    PubMed Central

    2014-01-01

    Background A recent study showed that the gaze patterns of amputee users of myoelectric prostheses differ markedly from those seen in anatomically intact subjects. Gaze behaviour is a promising outcome measures for prosthesis designers, as it appears to reflect the strategies adopted by amputees to compensate for the absence of proprioceptive feedback and uncertainty/delays in the control system, factors believed to be central to the difficulty in using prostheses. The primary aim of our study was to characterise visuomotor behaviours over learning to use a trans-radial myoelectric prosthesis. Secondly, as there are logistical advantages to using anatomically intact subjects in prosthesis evaluation studies, we investigated similarities in visuomotor behaviours between anatomically intact users of a trans-radial prosthesis simulator and experienced trans-radial myoelectric prosthesis users. Methods In part 1 of the study, we investigated visuomotor behaviours during performance of a functional task (reaching, grasping and manipulating a carton) in a group of seven anatomically intact subjects over learning to use a trans-radial myoelectric prosthesis simulator (Dataset 1). Secondly, we compared their patterns of visuomotor behaviour with those of four experienced trans-radial myoelectric prosthesis users (Dataset 2). We recorded task movement time, performance on the SHAP test of hand function and gaze behaviour. Results Dataset 1 showed that while reaching and grasping the object, anatomically intact subjects using the prosthesis simulator devoted around 90% of their visual attention to either the hand or the area of the object to be grasped. This pattern of behaviour did not change with training, and similar patterns were seen in Dataset 2. Anatomically intact subjects exhibited significant increases in task duration at their first attempts to use the prosthesis simulator. At the end of training, the values had decreased and were similar to those seen in Dataset

  7. Extraordinary plastic behaviour of the γ‧ precipitate in a directionally solidified nickel-based superalloy

    NASA Astrophysics Data System (ADS)

    Zhang, Peng; Ma, Lifeng; Yang, Gongxian; Song, Xiaolong

    2016-01-01

    The deformation behaviour of the γ‧ precipitate in a directionally solidified nickel-based superalloy is investigated using microscopic observations after tensile testing at room temperature. It is found that coarse γ‧ precipitates (604 nm) are sheared by strongly coupled dislocations, and some γ‧ precipitates are elongated to approximately 3-6 times of their original lengths. It reveals that, at room temperature, the γ‧ precipitate within the experimental superalloy has a significant plastic deformation capacity in comparison with Ni3Al bulk alloys. Based on the experimental observations, the extraordinary plastic behaviour of the γ‧ precipitate is analysed.

  8. Controllable optomechanical coupling in serially-coupled triple resonators

    SciTech Connect

    Huang, Chenguang Zhao, Yunsong; Fan, Jiahua; Zhu, Lin

    2014-12-15

    Radiation pressure can efficiently couple mechanical modes with optical modes in an optical cavity. The coupling efficiency is quite dependent on the interaction between the optical mode and mechanical mode. In this report, we investigate a serially-coupled triple resonator system, where a freestanding beam is placed in the vicinity of the middle resonator. In this coupled system, we demonstrate that the mechanical mode of the free-standing beam can be selectively coupled to different resonance supermodes through the near field interaction.

  9. Age and aggregation trigger mating behaviour in the small hive beetle, Aethina tumida (Nitidulidae)

    NASA Astrophysics Data System (ADS)

    Mustafa, Sandra G.; Spooner-Hart, Robert; Duncan, Michael; Pettis, Jeffery S.; Steidle, Johannes L. M.; Rosenkranz, Peter

    2015-10-01

    This study aimed to investigate the poorly documented reproductive behaviour of the small hive beetle, Aethina tumida (Nitidulidae), a honey bee ( Apis mellifera) parasite. We described the mating behaviour in detail and tested the hypothesis that beetle aggregation plays a vital role in mating in this species. Gender preference was examined in the context of age-dependency and possible chemical communication. Beetles started mating at a high frequency 18 days after emergence from the soil but only if they were aggregated ( p < 0.001); mating was infrequent when beetles were paired. Males in aggregation also tried to copulate with males and only copulated more frequently with females at 18 days after emergence from soil ( p < 0.001) in contrast to newly emerged, 7-day-old and 60-day-old beetles. Males and females spent more time in social contact with the opposite sex ( p < 0.01) when they were 18 days old in contrast to 7-day-old beetles. Filter papers which had been in contact with 21-day-old beetles were highly attractive to similar-aged beetles of the opposite sex ( p < 0.01). This suggests that chemical substances produced by the beetles themselves play a role in mating. Mating behaviour was characterised by a short pre-copulation courtship and female aggression towards other females and copulating couples. Both behaviours may be indicative of cryptic female choice. Delayed onset of reproductive behaviour is typical of many polygamous species, whilst the indispensability of aggregation for onset of sexual behaviour seems to be a feature unique to A. tumida. Both strategies support mass reproduction in this parasitic species, enabling A. tumida to overcome its honey bee host colony, and are probably triggered by chemotactic cues.

  10. From REM sleep behaviour disorder to status dissociatus: insights into the maze of states of being.

    PubMed

    Vetrugno, Roberto; Montagna, Pasquale

    2011-12-01

    Sleep is a coordinated process involving more or less simultaneous changes in sensory, motor, autonomic, hormonal, and cerebral processes. On the other hand, none of the changes occurring with sleep are invariably coupled to sleep. EEG synchrony, heat loss, sleep-related hormone secretion, and even REM-related motoneuron paralysis may occur independent of the parent state. In REM sleep behaviour disorder (RBD) the muscle tone of wakefulness intrudes into REM sleep, allowing the release of dream-enacting behaviours. Status dissociatus (SD) is a condition in which brain and mind are in disarray along the boundaries of sleep and wakefulness. The existence of such dissociated behaviours shows that they have separate neuronal control systems and indicates that the whole organization of sleep is an emergent property of the collective neuronal systems to synchronize. Insults to the brain can drastically alter the circuitries responsible for maintaining the integrity of wakefulness, NREM sleep, and REM sleep. As a consequence, the basic states of existence can become admixed and interchanged with striking disturbances of consciousness, brain electrophysiology, and the behavioural and polygraphic expression of sleep and wakefulness. The evolution of RBD into SD may result from a disarray of (brainstem) structures that orchestrate the whole brain wake-sleep conditions, but with preserved discrete systems and dissociable strategies to still place navigation in wake and sleep. Advances in the fields of genetics, neuroimaging, and behavioural neurology will expand the understanding of the mechanisms underlying the organization of the states of being along with their somatic/behavioural manifestations.

  11. Age and aggregation trigger mating behaviour in the small hive beetle, Aethina tumida (Nitidulidae).

    PubMed

    Mustafa, Sandra G; Spooner-Hart, Robert; Duncan, Michael; Pettis, Jeffery S; Steidle, Johannes L M; Rosenkranz, Peter

    2015-10-01

    This study aimed to investigate the poorly documented reproductive behaviour of the small hive beetle, Aethina tumida (Nitidulidae), a honey bee (Apis mellifera) parasite. We described the mating behaviour in detail and tested the hypothesis that beetle aggregation plays a vital role in mating in this species. Gender preference was examined in the context of age-dependency and possible chemical communication. Beetles started mating at a high frequency 18 days after emergence from the soil but only if they were aggregated (p < 0.001); mating was infrequent when beetles were paired. Males in aggregation also tried to copulate with males and only copulated more frequently with females at 18 days after emergence from soil (p < 0.001) in contrast to newly emerged, 7-day-old and 60-day-old beetles. Males and females spent more time in social contact with the opposite sex (p < 0.01) when they were 18 days old in contrast to 7-day-old beetles. Filter papers which had been in contact with 21-day-old beetles were highly attractive to similar-aged beetles of the opposite sex (p < 0.01). This suggests that chemical substances produced by the beetles themselves play a role in mating. Mating behaviour was characterised by a short pre-copulation courtship and female aggression towards other females and copulating couples. Both behaviours may be indicative of cryptic female choice. Delayed onset of reproductive behaviour is typical of many polygamous species, whilst the indispensability of aggregation for onset of sexual behaviour seems to be a feature unique to A. tumida. Both strategies support mass reproduction in this parasitic species, enabling A. tumida to overcome its honey bee host colony, and are probably triggered by chemotactic cues..

  12. Social behaviour: can it change the brain?

    PubMed Central

    Fernald, Russell D.

    2015-01-01

    Dominance hierarchies are ubiquitous in social species. Social status is established initially through physical conflict between individuals and then communicated directly by a variety of signals. Social interactions depend critically on the relative social status of those interacting. But how do individuals acquire the information they need to modulate their behaviour and how do they use that information to decide what to do? What brain mechanisms might underlie such animal cognition? Using a particularly suitable fish model system that depends on complex social interactions, we report how the social context of behaviour shapes the brain and, in turn, alters the behaviour of animals as they interact. Animals observe social interactions carefully to gather information vicariously that then guides their future behaviour. Social opportunities produce rapid changes in gene expression in key nuclei in the brain and these genomic responses may prepare the individual to modify its behaviour to move into a different social niche. Both social success and failure produce changes in neuronal cell size and connectivity in key nuclei. Understanding mechanisms through which social information is transduced into cellular and molecular changes will provide a deeper understanding of the brain systems responsible for animal cognition. PMID:26085689

  13. Risk compensation behaviours in construction workers' activities.

    PubMed

    Feng, Yingbin; Wu, Peng

    2015-01-01

    The purpose of this study was to test whether the construction workers have the tendency of engaging in risk compensation behaviours, and identify the demographic variables, which may influence the extent to which the construction workers may show risk compensation behaviours. Both quantitative (survey) and qualitative (interviews) approaches were used in this study. A questionnaire survey was conducted with all the construction workers on three building construction sites of a leading construction company in Australia. Semi-structured interviews were then conducted to validate the findings of the quantitative research. The findings indicate that workers tend to show risk compensation behaviours in the construction environment. The workers with more working experience, higher education, or having never been injured at work before have a higher tendency to show risk compensation in their activities than the others. The implication is that contractors need to assess the potential influence of workers' risk compensation behaviours when evaluating the effect of risk control measures. It is recommended that supervisors pay more attention to the behavioural changes of those workers who have more experience, higher education, and have never been injured before after the implementation of new safety control measures on construction site. PMID:24134314

  14. Urbanisation shapes behavioural responses to a pesticide.

    PubMed

    Tüzün, Nedim; Debecker, Sara; Op de Beeck, Lin; Stoks, Robby

    2015-06-01

    The degree of urbanisation is rapidly increasing worldwide. Due to anthropogenic impact, urban populations are exposed to higher levels of contaminants and higher temperatures. Despite this, urbanisation is a largely overlooked spatial component in ecotoxicology. We tested in a common garden rearing experiment whether replicated urban and rural populations of the damselfly Coenagrion puella differ in their vulnerability to sublethal levels of a widespread pesticide, chlorpyrifos, in terms of ecologically relevant behaviours (exploration behaviour, activity, boldness and food intake), and to what extent these patterns are affected by temperature (20 and 24°C). Except boldness, all behaviours were affected by previous pesticide exposure. While the pesticide did not affect exploration behaviour at 20°C, it was associated with increased exploration at 24°C, which may reflect an increased toxicity of chlorpyrifos at higher temperatures. Importantly, rural and urban larvae showed consistently different, sometimes even opposite behavioural responses to pesticide exposure. When exposed to the pesticide, rural larvae decreased activity and food intake at both temperatures; urban larvae instead increased activity at both temperatures and only reduced food intake at the high temperature. This suggests that urban larvae were less affected by the pesticide, which would be consistent with a scenario of local adaptation to higher contaminant levels. Our results highlight that urbanisation may be an important factor to arrive at a spatially explicit ecological risk assessment, and may be an ignored reason why studies on the same species may generate widely different vulnerabilities to pesticides.

  15. Epidemic cycles driven by host behaviour.

    PubMed

    Althouse, Benjamin M; Hébert-Dufresne, Laurent

    2014-10-01

    Host immunity and demographics (the recruitment of susceptibles via birthrate) have been demonstrated to be a key determinant of the periodicity of measles, pertussis and dengue epidemics. However, not all epidemic cycles are from pathogens inducing sterilizing immunity or are driven by demographics. Many sexually transmitted infections are driven by sexual behaviour. We present a mathematical model of disease transmission where individuals can disconnect and reconnect depending on the infectious status of their contacts. We fit the model to historic syphilis (Treponema pallidum) and gonorrhea (Neisseria gonorrhoeae) incidence in the USA and explore potential intervention strategies against syphilis. We find that cycles in syphilis incidence can be driven solely by changing sexual behaviour in structured populations. Our model also explains the lack of similar cycles in gonorrhea incidence even if the two infections share the same propagation pathways. Our model similarly illustrates how sudden epidemic outbreaks can occur on time scales smaller than the characteristic demographic time scale of the population and that weaker infections can lead to more violent outbreaks. Behaviour also appears to be critical for control strategies as we found a bigger sensitivity to behavioural interventions than antibiotic treatment. Thus, behavioural interventions may play a larger role than previously thought, especially in the face of antibiotic resistance and low intervention efficacies. PMID:25100316

  16. Antisocial and callous behaviour in children.

    PubMed

    Viding, Essi; Seara-Cardoso, Ana; McCrory, Eamon J

    2014-01-01

    Antisocial behaviour is one of the most common reasons for a childhood referral to mental health and educational services and represents a substantial public health cost. Callous-unemotional traits can be used to distinguish children who are capable of pre-meditated antisocial behaviour and violence from those whose antisocial behaviour and violence are primarily impulsive and threat reactive. Decades of developmental psychopathology research have shown that children with antisocial behaviour are thus a heterogeneous group and, for interventions to be successful, it is critical that distinct subgroups of children receive services that best match their profile of vulnerabilities and strengths. Recent advances in genetic and brain imaging research in the field have made important contributions to our understanding of the developmental vulnerability that callous-unemotional traits represent. In this chapter, we provide an overview of the current evidence base with regard to genetic and neuroscience findings of callous-unemotional traits and antisocial behaviour with callous-unemotional traits. We also discuss the implications of these findings for prevention and intervention, and finish by outlining what we consider are necessary directions for future research.

  17. Urbanisation shapes behavioural responses to a pesticide.

    PubMed

    Tüzün, Nedim; Debecker, Sara; Op de Beeck, Lin; Stoks, Robby

    2015-06-01

    The degree of urbanisation is rapidly increasing worldwide. Due to anthropogenic impact, urban populations are exposed to higher levels of contaminants and higher temperatures. Despite this, urbanisation is a largely overlooked spatial component in ecotoxicology. We tested in a common garden rearing experiment whether replicated urban and rural populations of the damselfly Coenagrion puella differ in their vulnerability to sublethal levels of a widespread pesticide, chlorpyrifos, in terms of ecologically relevant behaviours (exploration behaviour, activity, boldness and food intake), and to what extent these patterns are affected by temperature (20 and 24°C). Except boldness, all behaviours were affected by previous pesticide exposure. While the pesticide did not affect exploration behaviour at 20°C, it was associated with increased exploration at 24°C, which may reflect an increased toxicity of chlorpyrifos at higher temperatures. Importantly, rural and urban larvae showed consistently different, sometimes even opposite behavioural responses to pesticide exposure. When exposed to the pesticide, rural larvae decreased activity and food intake at both temperatures; urban larvae instead increased activity at both temperatures and only reduced food intake at the high temperature. This suggests that urban larvae were less affected by the pesticide, which would be consistent with a scenario of local adaptation to higher contaminant levels. Our results highlight that urbanisation may be an important factor to arrive at a spatially explicit ecological risk assessment, and may be an ignored reason why studies on the same species may generate widely different vulnerabilities to pesticides. PMID:25863029

  18. Antisocial and callous behaviour in children.

    PubMed

    Viding, Essi; Seara-Cardoso, Ana; McCrory, Eamon J

    2014-01-01

    Antisocial behaviour is one of the most common reasons for a childhood referral to mental health and educational services and represents a substantial public health cost. Callous-unemotional traits can be used to distinguish children who are capable of pre-meditated antisocial behaviour and violence from those whose antisocial behaviour and violence are primarily impulsive and threat reactive. Decades of developmental psychopathology research have shown that children with antisocial behaviour are thus a heterogeneous group and, for interventions to be successful, it is critical that distinct subgroups of children receive services that best match their profile of vulnerabilities and strengths. Recent advances in genetic and brain imaging research in the field have made important contributions to our understanding of the developmental vulnerability that callous-unemotional traits represent. In this chapter, we provide an overview of the current evidence base with regard to genetic and neuroscience findings of callous-unemotional traits and antisocial behaviour with callous-unemotional traits. We also discuss the implications of these findings for prevention and intervention, and finish by outlining what we consider are necessary directions for future research. PMID:24357438

  19. Long-term observations of siamang behaviour.

    PubMed

    Chivers, D J; Raemaekers, J J; Aldrich-Blake, F P

    1975-01-01

    Long-term observations are presented on the behaviour of the siamang ape, Symphalangus syndactylus, in the lowland forest of central Malaya. The data were collected during two dry and three fruiting seasons between 1969 and 1973 inclusive on two groups with adjacent ranges; comparisons are made within and between sample periods, and between groups. The influence of weather on daily activities is considered. Food intake is analysed in terms of number of food trees, number of visits to these trees, and the cumulative time spent feeding on various food categories. Ranging behaviour is investigated in terms of distance travelled, area covered, and distribution of time and of food trees about the range. The occurrence of calling is described and compared with that of the white-handed gibbon in the same area. A discussion ensues on each of these aspects of behaviour in turn. Emphasis is laid on the similarity of behaviour of the two groups at any one time, and on the degree of their response to the fluctuations of environment variables. Finally, the application to siamang of ranging concepts currently used in animal behaviour is considered briefly.

  20. Breed differences in behavioural development in kittens.

    PubMed

    Marchei, P; Diverio, S; Falocci, N; Fatjó, J; Ruiz-de-la-Torre, J L; Manteca, X

    2009-03-23

    Differences in behaviour of pure breed cats have been suggested but not wholly investigated. Oriental/Siamese/Abyssinian (OSA) kittens (n=43) were weekly compared with Norwegian Forest (NFO) kittens (n=39) from the 4th to the 10th week of age in a repeated Open Field Test (OFT) paradigm. Heart rate (HR) and rectal temperature (RT) before and after the test, and behavioural responses during the OFT were recorded. Behaviours registered were analysed by focal animal sampling. Significant breed differences were found; cats of the northern zones (NFO) seem to develop earlier thermoregulatory abilities. Precocious opening of eyes, higher locomotion scores and longer time spent standing, observed in OSA kittens may indicate an earlier neurological development. Inter breed differences recorded for exploration and locomotion seem to indicate coping style divergences: in the OFT challenging situation OSA kittens presented higher emotional tachycardia and performed more passively, with a faster decline in exploration and locomotion scores. NFO kittens exerted a more active behaviour as they spent more time exploring the arena and in escape attempts. Notwithstanding OSA and NFO cat selection was mainly aimed to improve divergent morphological traits, some different behavioural and physiological traits seem to have been maintained or co-selected within each breed.

  1. Maternal care and subsocial behaviour in spiders.

    PubMed

    Yip, Eric C; Rayor, Linda S

    2014-05-01

    While most spiders are solitary and opportunistically cannibalistic, a variety of social organisations has evolved in a minority of spider species. One form of social organisation is subsociality, in which siblings remain together with their parent for some period of time but disperse prior to independent reproduction. We review the literature on subsocial and maternal behaviour in spiders to highlight areas in which subsocial spiders have informed our understanding of social evolution and to identify promising areas of future research. We show that subsocial behaviour has evolved independently at least 18 times in spiders, across a wide phylogenetic distribution. Subsocial behaviour is diverse in terms of the form of care provided by the mother, the duration of care and sibling association, the degree of interaction and cooperation among siblings, and the use of vibratory and chemical communication. Subsocial spiders are useful model organisms to study various topics in ecology, such as kin recognition and the evolution of cheating and its impact on societies. Further, why social behaviour evolved in some lineages and not others is currently a topic of debate in behavioural ecology, and we argue that spiders offer an opportunity to untangle the ecological causes of parental care, which forms the basis of many other animal societies.

  2. Behavioural phenotypes predict disease susceptibility and infectiousness.

    PubMed

    Araujo, Alessandra; Kirschman, Lucas; Warne, Robin W

    2016-08-01

    Behavioural phenotypes may provide a means for identifying individuals that disproportionally contribute to disease spread and epizootic outbreaks. For example, bolder phenotypes may experience greater exposure and susceptibility to pathogenic infection because of distinct interactions with conspecifics and their environment. We tested the value of behavioural phenotypes in larval amphibians for predicting ranavirus transmission in experimental trials. We found that behavioural phenotypes characterized by latency-to-food and swimming profiles were predictive of disease susceptibility and infectiousness defined as the capacity of an infected host to transmit an infection by contacts. While viral shedding rates were positively associated with transmission, we also found an inverse relationship between contacts and infections. Together these results suggest intrinsic traits that influence behaviour and the quantity of pathogens shed during conspecific interactions may be an important contributor to ranavirus transmission. These results suggest that behavioural phenotypes provide a means to identify individuals more likely to spread disease and thus give insights into disease outbreaks that threaten wildlife and humans. PMID:27555652

  3. Epidemic cycles driven by host behaviour

    PubMed Central

    Althouse, Benjamin M.; Hébert-Dufresne, Laurent

    2014-01-01

    Host immunity and demographics (the recruitment of susceptibles via birthrate) have been demonstrated to be a key determinant of the periodicity of measles, pertussis and dengue epidemics. However, not all epidemic cycles are from pathogens inducing sterilizing immunity or are driven by demographics. Many sexually transmitted infections are driven by sexual behaviour. We present a mathematical model of disease transmission where individuals can disconnect and reconnect depending on the infectious status of their contacts. We fit the model to historic syphilis (Treponema pallidum) and gonorrhea (Neisseria gonorrhoeae) incidence in the USA and explore potential intervention strategies against syphilis. We find that cycles in syphilis incidence can be driven solely by changing sexual behaviour in structured populations. Our model also explains the lack of similar cycles in gonorrhea incidence even if the two infections share the same propagation pathways. Our model similarly illustrates how sudden epidemic outbreaks can occur on time scales smaller than the characteristic demographic time scale of the population and that weaker infections can lead to more violent outbreaks. Behaviour also appears to be critical for control strategies as we found a bigger sensitivity to behavioural interventions than antibiotic treatment. Thus, behavioural interventions may play a larger role than previously thought, especially in the face of antibiotic resistance and low intervention efficacies. PMID:25100316

  4. Risk compensation behaviours in construction workers' activities.

    PubMed

    Feng, Yingbin; Wu, Peng

    2015-01-01

    The purpose of this study was to test whether the construction workers have the tendency of engaging in risk compensation behaviours, and identify the demographic variables, which may influence the extent to which the construction workers may show risk compensation behaviours. Both quantitative (survey) and qualitative (interviews) approaches were used in this study. A questionnaire survey was conducted with all the construction workers on three building construction sites of a leading construction company in Australia. Semi-structured interviews were then conducted to validate the findings of the quantitative research. The findings indicate that workers tend to show risk compensation behaviours in the construction environment. The workers with more working experience, higher education, or having never been injured at work before have a higher tendency to show risk compensation in their activities than the others. The implication is that contractors need to assess the potential influence of workers' risk compensation behaviours when evaluating the effect of risk control measures. It is recommended that supervisors pay more attention to the behavioural changes of those workers who have more experience, higher education, and have never been injured before after the implementation of new safety control measures on construction site.

  5. Social Behaviour of Captive Belugas, Delphinapterus Leucas.

    NASA Astrophysics Data System (ADS)

    Recchia, Cheri Anne

    1994-01-01

    Focal-animal sampling techniques developed for investigating social behaviour of terrestrial animals were adapted for studying captive belugas, providing quantitative descriptions of social relationships among individuals. Five groups of captive belugas were observed, allowing a cross -sectional view of sociality in groups of diverse sizes and compositions. Inter-individual distances were used to quantify patterns of spatial association. A set of social behaviours for which actor and recipient could be identified was defined to characterize dyadic interactions. The mother-calf pair spent more time together, and interacted more often than adults. The calf maintained proximity with his mother; larger adults generally maintained proximity with smaller adults. Among adults, larger groups performed more kinds of behaviours and interacted at higher rates than smaller groups. Within dyads, the larger whale performed more aggressive behaviours and the smaller whale more submissive behaviours. Clear dominance relations existed in three groups, with larger whales dominant to smaller whales. Vocalizations of three groups were classified subjectively, based on aural impressions and visual inspection of spectrograms, but most signals appeared graded. Statistical analyses of measured acoustic features confirmed subjective impressions that vocalizations could not be classified into discrete and homogeneous categories. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-553-5668; Fax 617-253-1690.).

  6. Periodic activations of behaviours and emotional adaptation in behaviour-based robotics

    NASA Astrophysics Data System (ADS)

    Burattini, Ernesto; Rossi, Silvia

    2010-09-01

    The possible modulatory influence of motivations and emotions is of great interest in designing robotic adaptive systems. In this paper, an attempt is made to connect the concept of periodic behaviour activations to emotional modulation, in order to link the variability of behaviours to the circumstances in which they are activated. The impact of emotion is studied, described as timed controlled structures, on simple but conflicting reactive behaviours. Through this approach it is shown that the introduction of such asynchronies in the robot control system may lead to an adaptation in the emergent behaviour without having an explicit action selection mechanism. The emergent behaviours of a simple robot designed with both a parallel and a hierarchical architecture are evaluated and compared.

  7. Air-Coupled Vibrometry

    NASA Astrophysics Data System (ADS)

    Döring, D.; Solodov, I.; Busse, G.

    Sound and ultrasound in air are the products of a multitude of different processes and thus can be favorable or undesirable phenomena. Development of experimental tools for non-invasive measurements and imaging of airborne sound fields is of importance for linear and nonlinear nondestructive material testing as well as noise control in industrial or civil engineering applications. One possible solution is based on acousto-optic interaction, like light diffraction imaging. The diffraction approach usually requires a sophisticated setup with fine optical alignment barely applicable in industrial environment. This paper focuses on the application of the robust experimental tool of scanning laser vibrometry, which utilizes commercial off-the-shelf equipment. The imaging technique of air-coupled vibrometry (ACV) is based on the modulation of the optical path length by the acoustic pressure of the sound wave. The theoretical considerations focus on the analysis of acousto-optical phase modulation. The sensitivity of the ACV in detecting vibration velocity was estimated as ~1 mm/s. The ACV applications to imaging of linear airborne fields are demonstrated for leaky wave propagation and measurements of ultrasonic air-coupled transducers. For higher-intensity ultrasound, the classical nonlinear effect of the second harmonic generation was measured in air. Another nonlinear application includes a direct observation of the nonlinear air-coupled emission (NACE) from the damaged areas in solid materials. The source of the NACE is shown to be strongly localized around the damage and proposed as a nonlinear "tag" to discern and image the defects.

  8. Sealing coupling. [LMFBR

    DOEpatents

    Pardini, J.A.; Brubaker, R.C.; Rusnak, J.J.

    1982-09-20

    Disclosed is a remotely operable releasable sealing coupling which provides fluid-tight joinder of upper and a lower conduit sections. Each conduit section has a concave conical sealing surface adjacent its end portion. A tubular sleeve having convex spherical ends is inserted between the conduit ends to form line contact with the concave conical end portions. An inwardly projecting lip located at one end of the sleeve cooperates with a retaining collar formed on the upper pipe end to provide swivel capture for the sleeve. The upper conduit section also includes a tapered lower end portion which engages the inside surface of the sleeve to limit misalignment of the connected conduit sections.

  9. Influence of the Monitored Youth Mentoring Program for adolescents with behavioural problems and behavioural disorders.

    PubMed

    Boras, Sofija; Zuckerman, Zora Itković

    2008-09-01

    This aimed to measure the influence of the Monitored Youth Mentoring Program (MYMP) for adolescents with behavioural problems and behavioural disorders. The MYMP commenced in 1997 and was completed in 2003. The model of the program was for one university student of Pedagogy to mentor one pupil between the ages of 13 and 17 years, demonstrating risk seeking behaviours for a whole school year. The specimen group was made up of 141 pupils, approximately 20 pupils from each year level. The short-term goal was to influence positive change in participants demonstrating risk seeking behaviour. The long-term goal was to enhance the respective school's programs to enable preventative approaches to lessen negative and risk seeking behaviours amongst pupils with behavioural problems and behavioural disorders. The research results demonstrate statistically significant success of the applied program in two measured variables. Firstly, learning success (p < 0.05), and secondly a decrease in truancy and disciplinary misdemeanours (p < 0.05). Both of which were observed in participants with behavioural problems. The program was not as successful for participants with behavioural disorders, but not without some effect. Although the program can be generally described as achieving a medium level of success, the fact that there was a lack of progressive worsening in participant's behaviour is a substantial bi-product of the program. The mentors involved in the program made it extremely clear by their feedback that, MYMP positively enhanced their formal Pedagogy training, through hands-on practise that they otherwise would not have received through their academic programs. They were provided with vital exposure to a preventative program and managed to gain insight into the possibilities of introducing early intervention and prevention into Croatian schools. PMID:18982754

  10. Virtual design of electrospun-like gelatin scaffolds: the effect of three-dimensional fibre orientation on elasticity behaviour.

    PubMed

    Guessasma, S; Oyen, M

    2016-01-14

    Remarkable mechanical performance of biological tissues is explained by a hierarchical fibrous structure. Designing materials that have similar properties is challenging because of the need to assess complex deformation mechanisms. In order to shed more light on architectural possibilities of biopolymer fibrous networks, we propose a numerical study that relates the fibre arrangement to the elastic modulus of a gelatin scaffold obtained using electrospinning. The adopted approach is based on the virtual designing of scaffolds using all possible combinations of Euler angles that define fibre orientations including preferable alignment. The generated networks are converted into a finite element model and the predicted elastic behaviour is examined. Predictions show that the fibre alignment achieved experimentally in biopolymer fibrous networks is for most of the fibres exhibiting an orthotropic behaviour. Some particular combinations of Euler angles allow transverse isotropic architectures while only limited cases are isotropic. A large sensitivity of Young's moduli to Euler angles is achieved describing multiple scenarios of independent anisotropic behaviours. An anisotropy ratio of the elastic behaviour is suggested based on a suitable combination of elastic moduli. Such a ratio exhibits a wide variation depending on individual and coupled effects of Euler angles. The finite element model predicts 2D, 3D and 4D maps representing all possible configurations of fibre alignment and their consequences on elastic behaviour. The predicted fibre orientation representing the observed anisotropic behaviour of electrospun gelatin networks demonstrates unbalanced contributions of in-plane and out-of plane fibres for a large range of processing conditions.

  11. Dynamics of atom-field probability amplitudes in a coupled cavity system with Kerr non-linearity

    SciTech Connect

    Priyesh, K. V.; Thayyullathil, Ramesh Babu

    2014-01-28

    We have investigated the dynamics of two cavities coupled together via photon hopping, filled with Kerr non-linear medium and each containing a two level atom in it. The evolution of various atom (field) state probabilities of the coupled cavity system in two excitation sub space are obtained numerically. Detailed analysis has been done by taking different initial conditions of the system, with various coupling strengths and by varying the susceptibility of the medium. The role of susceptibility factor, on the dynamics atom field probability has been examined. In a coupled cavity system with strong photon hopping it is found that the susceptibility factor modifies the behaviour of probability amplitudes.

  12. The influence of social norms on the dynamics of vaccinating behaviour for paediatric infectious diseases.

    PubMed

    Oraby, Tamer; Thampi, Vivek; Bauch, Chris T

    2014-04-01

    Mathematical models that couple disease dynamics and vaccinating behaviour often assume that the incentive to vaccinate disappears if disease prevalence is zero. Hence, they predict that vaccine refusal should be the rule, and elimination should be difficult or impossible. In reality, countries with non-mandatory vaccination policies have usually been able to maintain elimination or very low incidence of paediatric infectious diseases for long periods of time. Here, we show that including injunctive social norms can reconcile such behaviour-incidence models to observations. Adding social norms to a coupled behaviour-incidence model enables the model to better explain pertussis vaccine uptake and disease dynamics in the UK from 1967 to 2010, in both the vaccine-scare years and the years of high vaccine coverage. The model also illustrates how a vaccine scare can perpetuate suboptimal vaccine coverage long after perceived risk has returned to baseline, pre-vaccine-scare levels. However, at other model parameter values, social norms can perpetuate depressed vaccine coverage during a vaccine scare well beyond the time when the population's baseline vaccine risk perception returns to pre-scare levels. Social norms can strongly suppress vaccine uptake despite frequent outbreaks, as observed in some small communities. Significant portions of the parameter space also exhibit bistability, meaning long-term outcomes depend on the initial conditions. Depending on the context, social norms can either support or hinder immunization goals. PMID:24523276

  13. The influence of social norms on the dynamics of vaccinating behaviour for paediatric infectious diseases

    PubMed Central

    Oraby, Tamer; Thampi, Vivek; Bauch, Chris T.

    2014-01-01

    Mathematical models that couple disease dynamics and vaccinating behaviour often assume that the incentive to vaccinate disappears if disease prevalence is zero. Hence, they predict that vaccine refusal should be the rule, and elimination should be difficult or impossible. In reality, countries with non-mandatory vaccination policies have usually been able to maintain elimination or very low incidence of paediatric infectious diseases for long periods of time. Here, we show that including injunctive social norms can reconcile such behaviour-incidence models to observations. Adding social norms to a coupled behaviour-incidence model enables the model to better explain pertussis vaccine uptake and disease dynamics in the UK from 1967 to 2010, in both the vaccine-scare years and the years of high vaccine coverage. The model also illustrates how a vaccine scare can perpetuate suboptimal vaccine coverage long after perceived risk has returned to baseline, pre-vaccine-scare levels. However, at other model parameter values, social norms can perpetuate depressed vaccine coverage during a vaccine scare well beyond the time when the population's baseline vaccine risk perception returns to pre-scare levels. Social norms can strongly suppress vaccine uptake despite frequent outbreaks, as observed in some small communities. Significant portions of the parameter space also exhibit bistability, meaning long-term outcomes depend on the initial conditions. Depending on the context, social norms can either support or hinder immunization goals. PMID:24523276

  14. Incentivizing behaviour change to improve diabetes care.

    PubMed

    Petry, N M; Cengiz, E; Wagner, J A; Hood, K K; Carria, L; Tamborlane, W V

    2013-12-01

    Behavioural economics refers to the study of psychological and cognitive factors that relate to decision-making processes. This field is being applied increasingly to health care settings, in which patients receive tangible reinforcers or incentives for meeting objective behavioural criteria consistent with healthy lifestyles. This article reviews the background and efficacy of reinforcement interventions in general, and then as applied to behaviours related to diabetes prevention and management. Specifically, reinforcement interventions have been applied with some notable success towards promoting greater attendance at medical appointments, enhancing weight loss efforts, augmenting exercising regimes, improving medication adherence and increasing blood glucose monitoring. Suggestions for promising areas of future research are provided, keeping in mind the controversial nature of these interventions.

  15. Managing behavioural and psychological symptoms in dementia

    PubMed Central

    Macfarlane, Stephen; O’Connor, Daniel

    2016-01-01

    SUMMARY Most patients with dementia have some behavioural and psychological symptoms. While aggression and agitation are easily recognised, symptoms such as apathy may be overlooked. Behavioural and psychological symptoms should be managed without drugs whenever possible. Although there is little evidence to support their use, antipsychotic drugs are often prescribed to people with dementia. Before prescribing it is important to exclude other causes of altered behaviour, such as pain or infection. Some symptoms may be artefacts of memory loss rather than psychosis. Patients with dementia who are prescribed antipsychotic drugs have an increased risk of falls, hospitalisation and death. They should be regularly monitored for adverse effects. If the patient’s symptoms resolve with drug treatment, reduce the dose after two or three months. Stop the drug if the symptoms do not return. PMID:27756974

  16. Sudden gains in behavioural activation for depression.

    PubMed

    Masterson, Ciara; Ekers, David; Gilbody, Simon; Richards, David; Toner-Clewes, Benjamin; McMillan, Dean

    2014-09-01

    Sudden gains have been linked to improved outcomes in cognitive behaviour therapy for depression. The relationship between sudden gains and outcome is less clear in other treatment modalities, including interpersonal psychotherapy and supportive expressive therapy, which may indicate different mechanisms of change between treatment modalities. The current study examined sudden gains in adults meeting diagnostic criteria for depression (N = 40) offered up to 12 sessions of behavioural activation treatment. Sudden gains were found in 42.5% of the sample. Sudden gains occurred early (median pre-gain session 2) and were related to outcome: those who experienced a sudden gain had significantly lower post-treatment scores on the PHQ-9. Furthermore, the proportion meeting the reliable and clinically significant change criteria at end of treatment was higher in the sudden gain group. These findings highlight the importance of understanding the mechanisms by which sudden gains relate to therapy outcome in behavioural activation.

  17. Natural selection can favour 'irrational' behaviour.

    PubMed

    McNamara, J M; Trimmer, P C; Houston, A I

    2014-01-01

    Understanding decisions is the fundamental aim of the behavioural sciences. The theory of rational choice is based on axiomatic principles such as transitivity and independence of irrelevant alternatives (IIA). Empirical studies have demonstrated that the behaviour of humans and other animals often seems irrational; there can be a lack of transitivity in choice and seemingly irrelevant alternatives can alter decisions. These violations of transitivity and IIA undermine rational choice theory. However, we show that an individual that is maximizing its rate of food gain can exhibit failure of transitivity and IIA. We show that such violations can be caused because a current option may disappear in the near future or a better option may reappear soon. Current food options can be indicative of food availability in the near future, and this key feature can result in apparently irrational behaviour.

  18. Optimally designing games for behavioural research.

    PubMed

    Rafferty, Anna N; Zaharia, Matei; Griffiths, Thomas L

    2014-07-01

    Computer games can be motivating and engaging experiences that facilitate learning, leading to their increasing use in education and behavioural experiments. For these applications, it is often important to make inferences about the knowledge and cognitive processes of players based on their behaviour. However, designing games that provide useful behavioural data are a difficult task that typically requires significant trial and error. We address this issue by creating a new formal framework that extends optimal experiment design, used in statistics, to apply to game design. In this framework, we use Markov decision processes to model players' actions within a game, and then make inferences about the parameters of a cognitive model from these actions. Using a variety of concept learning games, we show that in practice, this method can predict which games will result in better estimates of the parameters of interest. The best games require only half as many players to attain the same level of precision.

  19. Optimally designing games for behavioural research

    PubMed Central

    Rafferty, Anna N.; Zaharia, Matei; Griffiths, Thomas L.

    2014-01-01

    Computer games can be motivating and engaging experiences that facilitate learning, leading to their increasing use in education and behavioural experiments. For these applications, it is often important to make inferences about the knowledge and cognitive processes of players based on their behaviour. However, designing games that provide useful behavioural data are a difficult task that typically requires significant trial and error. We address this issue by creating a new formal framework that extends optimal experiment design, used in statistics, to apply to game design. In this framework, we use Markov decision processes to model players' actions within a game, and then make inferences about the parameters of a cognitive model from these actions. Using a variety of concept learning games, we show that in practice, this method can predict which games will result in better estimates of the parameters of interest. The best games require only half as many players to attain the same level of precision. PMID:25002821

  20. Sucker rod coupling

    SciTech Connect

    Klyne, A.A.

    1986-11-11

    An anti-friction sucker rod coupling is described for connecting a pair of sucker rods and centralizing them in a tubing string, comprising: an elongate, rigid, substantially cylindrical body member, each end of the body member forming means for threadably connecting the body member with a sucker rod. The body member further forms a transversely extending, substantially diametric, generally vertical slot extending therethrough. The body member further forms a pin bore, such pin bore extending transversely through the body member so as to intersect the slot substantially perpendicularly; a wheel member positioned within the slot to rotate in a generally vertical plane. The wheel member has a portion thereof extending beyond the periphery of the body member to engage the inner surface of the tubing string and centralize the coupling; and a pin mounted in the pin bore and supporting member thereon, whereby the wheel member is rotatable within the slot; the wheel member having sufficient clearance between its side surfaces and the wall surfaces of the slot, when the wheel member is centered in the slot on the pin, whereby the wheel member may shift along the pin to assist in ejecting sand and oil from the slot.

  1. How couples choose vasectomy.

    PubMed

    Schehl, M

    1997-01-01

    A study conducted by AVSC International between 1992 and 1995 found that couples around the world go through a highly similar decision-making process when they choose vasectomy as their family planning methods. Study findings are based upon in-depth, qualitative interviews with couples using vasectomy in Bangladesh, Mexico, Kenya, and Rwanda, where the prevalence of vasectomy is relatively low, and Sri Lanka and the US, where it is relatively high. 218 separate interviews were conducted with male and female partners. Concerns about the woman's health were cited by respondents in each country as reasons to cease childbearing and to opt for vasectomy as the means to achieving that end. Also, almost all respondents mentioned varying degrees of financial hardship as contributing to their decision to end childbearing. These findings highlight the concept of partnership in relationships and family planning decision-making, and demonstrate the importance of going beyond traditional stereotypes about gender roles in decision-making. Social influences and the potential risks of using other forms of contraception also contributed to the choice of using vasectomy. The decision-making process and lessons learned are discussed.

  2. Magnetically Coupled Calorimeters

    NASA Technical Reports Server (NTRS)

    Bandler, Simon

    2011-01-01

    Calorimeters that utilize the temperature sensitivity of magnetism have been under development for over 20 years. They have targeted a variety of different applications that require very high resolution spectroscopy. I will describe the properties of this sensor technology that distinguish it from other low temperature detectors and emphasize the types of application to which they appear best suited. I will review what has been learned so far about the best materials, geometries, and read-out amplifiers and our understanding of the measured performance and theoretical limits. I will introduce some of the applications where magnetic calorimeters are being used and also where they are in development for future experiments. So far, most magnetic calorimeter research has concentrated on the use of paramagnets to provide temperature sensitivity; recent studies have also focused on magnetically coupled calorimeters that utilize the diamagnetic response of superconductors. I will present some of the highlights of this research, and contrast the properties of the two magnetically coupled calorimeter types.

  3. Coupled biopolymer networks

    NASA Astrophysics Data System (ADS)

    Schwarz, J. M.; Zhang, Tao

    2015-03-01

    The actin cytoskeleton provides the cell with structural integrity and allows it to change shape to crawl along a surface, for example. The actin cytoskeleton can be modeled as a semiflexible biopolymer network that modifies its morphology in response to both external and internal stimuli. Just inside the inner nuclear membrane of a cell exists a network of filamentous lamin that presumably protects the heart of the cell nucleus--the DNA. Lamins are intermediate filaments that can also be modeled as semiflexible biopolymers. It turns out that the actin cytoskeletal biopolymer network and the lamin biopolymer network are coupled via a sequence of proteins that bridge the outer and inner nuclear membranes. We, therefore, probe the consequences of such a coupling via numerical simulations to understand the resulting deformations in the lamin network in response to perturbations in the cytoskeletal network. Such study could have implications for mechanical mechanisms of the regulation of transcription, since DNA--yet another semiflexible polymer--contains lamin-binding domains, and, thus, widen the field of epigenetics.

  4. Multiphysics Application Coupling Toolkit

    SciTech Connect

    Campbell, Michael T.

    2013-12-02

    This particular consortium implementation of the software integration infrastructure will, in large part, refactor portions of the Rocstar multiphysics infrastructure. Development of this infrastructure originated at the University of Illinois DOE ASCI Center for Simulation of Advanced Rockets (CSAR) to support the center's massively parallel multiphysics simulation application, Rocstar, and has continued at IllinoisRocstar, a small company formed near the end of the University-based program. IllinoisRocstar is now licensing these new developments as free, open source, in hopes to help improve their own and others' access to infrastructure which can be readily utilized in developing coupled or composite software systems; with particular attention to more rapid production and utilization of multiphysics applications in the HPC environment. There are two major pieces to the consortium implementation, the Application Component Toolkit (ACT), and the Multiphysics Application Coupling Toolkit (MPACT). The current development focus is the ACT, which is (will be) the substrate for MPACT. The ACT itself is built up from the components described in the technical approach. In particular, the ACT has the following major components: 1.The Component Object Manager (COM): The COM package provides encapsulation of user applications, and their data. COM also provides the inter-component function call mechanism. 2.The System Integration Manager (SIM): The SIM package provides constructs and mechanisms for orchestrating composite systems of multiply integrated pieces.

  5. Multiphysics Application Coupling Toolkit

    2013-12-02

    This particular consortium implementation of the software integration infrastructure will, in large part, refactor portions of the Rocstar multiphysics infrastructure. Development of this infrastructure originated at the University of Illinois DOE ASCI Center for Simulation of Advanced Rockets (CSAR) to support the center's massively parallel multiphysics simulation application, Rocstar, and has continued at IllinoisRocstar, a small company formed near the end of the University-based program. IllinoisRocstar is now licensing these new developments as free, openmore » source, in hopes to help improve their own and others' access to infrastructure which can be readily utilized in developing coupled or composite software systems; with particular attention to more rapid production and utilization of multiphysics applications in the HPC environment. There are two major pieces to the consortium implementation, the Application Component Toolkit (ACT), and the Multiphysics Application Coupling Toolkit (MPACT). The current development focus is the ACT, which is (will be) the substrate for MPACT. The ACT itself is built up from the components described in the technical approach. In particular, the ACT has the following major components: 1.The Component Object Manager (COM): The COM package provides encapsulation of user applications, and their data. COM also provides the inter-component function call mechanism. 2.The System Integration Manager (SIM): The SIM package provides constructs and mechanisms for orchestrating composite systems of multiply integrated pieces.« less

  6. The Relation between Intrapersonal and Interpersonal Staff Behaviour towards Clients with ID and Challenging Behaviour: A Validation Study of the Staff-Client Interactive Behaviour Inventory

    ERIC Educational Resources Information Center

    Willems, A. P. A. M.; Embregts, P. J. C. M.; Stams, G. J. J. M.; Moonen, X. M. H.

    2010-01-01

    Background: Interpersonal staff behaviour is one of the instigating factors associated with challenging behaviour in clients with intellectual disabilities (ID). There are several studies focusing on the influence of intrapersonal staff characteristics--such as beliefs, attributions and emotional reactions--on staff behaviour. Little is known,…

  7. Significant determinants of mouse pain behaviour.

    PubMed

    Minett, Michael S; Eijkelkamp, Niels; Wood, John N

    2014-01-01

    Transgenic mouse behavioural analysis has furthered our understanding of the molecular and cellular mechanisms underlying damage sensing and pain. However, it is not unusual for conflicting data on the pain phenotypes of knockout mice to be generated by reputable groups. Here we focus on some technical aspects of measuring mouse pain behaviour that are often overlooked, which may help explain discrepancies in the pain literature. We examined touch perception using von Frey hairs and mechanical pain thresholds using the Randall-Selitto test. Thermal pain thresholds were measured using the Hargreaves apparatus and a thermal place preference test. Sodium channel Nav1.7 knockout mice show a mechanical deficit in the hairy skin, but not the paw, whilst shaving the abdominal hair abolished this phenotype. Nav1.7, Nav1.8 and Nav1.9 knockout mice show deficits in noxious mechanosensation in the tail, but not the paw. TRPA1 knockout mice, however, have a loss of noxious mechanosensation in the paw but not the tail. Studies of heat and cold sensitivity also show variability depending on the intensity of the stimulus. Deleting Nav1.7, Nav1.8 or Nav1.9 in Nav1.8-positive sensory neurons attenuates responses to slow noxious heat ramps, whilst responses to fast noxious heat ramps are only reduced when Nav1.7 is lost in large diameter sensory neurons. Deleting Nav1.7 from all sensory neurons attenuates responses to noxious cooling but not extreme cold. Finally, circadian rhythms dramatically influence behavioural outcome measures such as von Frey responses, which change by 80% over the day. These observations demonstrate that fully characterising the phenotype of a transgenic mouse strain requires a range of behavioural pain models. Failure to conduct behavioural tests at different anatomical locations, stimulus intensities, and at different points in the circadian cycle may lead to a pain behavioural phenotype being misinterpreted, or missed altogether. PMID:25101983

  8. The QCD running coupling

    DOE PAGESBeta

    Deur, Alexandre; Brodsky, Stanley J.; de Téramond, Guy F.

    2016-05-09

    Here, we review present knowledge onmore » $$\\alpha_{s}$$, the Quantum Chromodynamics (QCD) running coupling. The dependence of $$\\alpha_s(Q^2)$$ on momentum transfer $Q$ encodes the underlying dynamics of hadron physics --from color confinement in the infrared domain to asymptotic freedom at short distances. We will survey our present theoretical and empirical knowledge of $$\\alpha_s(Q^2)$$, including constraints at high $Q^2$ predicted by perturbative QCD, and constraints at small $Q^2$ based on models of nonperturbative dynamics. In the first, introductory, part of this review, we explain the phenomenological meaning of the coupling, the reason for its running, and the challenges facing a complete understanding of its analytic behavior in the infrared domain. In the second, more technical, part of the review, we discuss $$\\alpha_s(Q^2)$$ in the high momentum transfer domain of QCD. We review how $$\\alpha_s$$ is defined, including its renormalization scheme dependence, the definition of its renormalization scale, the utility of effective charges, as well as `` Commensurate Scale Relations" which connect the various definitions of the QCD coupling without renormalization scale ambiguity. We also report recent important experimental measurements and advanced theoretical analyses which have led to precise QCD predictions at high energy. As an example of an important optimization procedure, we discuss the ``Principle of Maximum Conformality" which enhances QCD's predictive power by removing the dependence of the predictions for physical observables on the choice of the gauge and renormalization scheme. In last part of the review, we discuss $$\\alpha_s(Q^2)$$ in the low momentum transfer domain, where there has been no consensus on how to define $$\\alpha_s(Q^2)$$ or its analytic behavior. We will discuss the various approaches used for low energy calculations. Among them, we will discuss the light-front holographic approach to QCD in the strongly coupled

  9. Synchronisation effects on the behavioural performance and information dynamics of a simulated minimally cognitive robotic agent.

    PubMed

    Moioli, Renan C; Vargas, Patricia A; Husbands, Phil

    2012-09-01

    Oscillatory activity is ubiquitous in nervous systems, with solid evidence that synchronisation mechanisms underpin cognitive processes. Nevertheless, its informational content and relationship with behaviour are still to be fully understood. In addition, cognitive systems cannot be properly appreciated without taking into account brain-body- environment interactions. In this paper, we developed a model based on the Kuramoto Model of coupled phase oscillators to explore the role of neural synchronisation in the performance of a simulated robotic agent in two different minimally cognitive tasks. We show that there is a statistically significant difference in performance and evolvability depending on the synchronisation regime of the network. In both tasks, a combination of information flow and dynamical analyses show that networks with a definite, but not too strong, propensity for synchronisation are more able to reconfigure, to organise themselves functionally and to adapt to different behavioural conditions. The results highlight the asymmetry of information flow and its behavioural correspondence. Importantly, it also shows that neural synchronisation dynamics, when suitably flexible and reconfigurable, can generate minimally cognitive embodied behaviour. PMID:22810898

  10. Quantitative assessment of intrinsic noise for visually guided behaviour in zebrafish.

    PubMed

    Spilioti, Melissa; Vargesson, Neil; Neri, Peter

    2016-10-01

    All sensory devices, whether biological or artificial, carry appreciable amounts of intrinsic noise. When these internally generated perturbations are sufficiently large, the behaviour of the system is not solely driven by the external stimulus but also by its own spontaneous variability. Behavioural internal noise can be quantified, provided it is expressed in relative units of the noise source externally applied by the stimulus. In humans performing sensory tasks at near threshold performance, the size of internal noise is roughly equivalent to the size of the response fluctuations induced by the external noise source. It is not known how the human estimate compares with other animals, because behavioural internal noise has never been measured in other species. We have adapted the methodology used with humans to the zebrafish, a small teleost that displays robust visually-guided behaviour. Our measurements demonstrate that, under some conditions, it is possible to obtain viable estimates of internal noise in this vertebrate species; the estimates generally fall within the human range, suggesting that the properties of internal noise may reflect general constraints on stimulus-response coupling that apply across animal systems with substantially different characteristics. PMID:27491704

  11. Challenging behaviour: a challenge to change.

    PubMed

    van Berckelaer-Onnes, I A; van Loon, J; Peelen, A

    2002-09-01

    People with intellectual disability often exhibit severe behavioural problems. Treatment of these problems is frequently very difficult. In The Netherlands, parents, institutes, schools and others can request the services of an independent advisory team with a pool of professionals who have experience with individuals who exhibit challenging behaviour. In this article the methods of the team will be described using a 24-year-old man as an example. The process took almost 7 years. Finally, this man, who had been living full time in one room in total isolation from the rest of the world, fulfilled his heart's desire--visiting the UK by Hovercraft. PMID:12212917

  12. Human behaviour: Egalitarian motive and altruistic punishment.

    PubMed

    Fowler, James H; Johnson, Tim; Smirnov, Oleg

    2005-01-01

    Altruistic punishment is a behaviour in which individuals punish others at a cost to themselves in order to provide a public good. Fehr and Gächter present experimental evidence in humans indicating that negative emotions towards non-cooperators motivate punishment, which, in turn, provokes a high degree of cooperation. Using Fehr and Gächter's original data, we provide an alternative analysis of their experiment that suggests that egalitarian motives are more important than motives for punishing non-cooperative behaviour. This finding is consistent with evidence that humans may have an evolutionary incentive to punish the highest earners in order to promote equality, rather than cooperation.

  13. Mechanisms of chromosome behaviour during mitosis

    PubMed Central

    Walczak, Claire E.; Cai, Shang; Khodjakov, Alexey

    2010-01-01

    For over a century, scientists have strived to understand the mechanisms that govern the accurate segregation of chromosomes during mitosis. The most intriguing feature of this process, which is particularly prominent in higher eukaryotes, is the complex behaviour exhibited by the chromosomes. This behaviour is based on specific and highly regulated interactions between the chromosomes and spindle microtubules. Recent discoveries, enabled by high-resolution imaging combined with the various genetic, molecular, cell biological and chemical tools, support the idea that establishing and controlling the dynamic interaction between chromosomes and microtubules is a major factor in genomic fidelity. PMID:20068571

  14. Narcolepsy presenting as REM sleep behaviour disorder.

    PubMed

    Bonakis, Anastasios; Howard, Robin S; Williams, Adrian

    2008-05-01

    REM sleep behaviour disorder (RBD) is a neurological condition well known to be associated with the synucleinopathies in middle-aged patients. However, there is much less data concerning its development, evolution, and association with other disorders in younger patients. We report two patients aged less than 33 years who presented with clinical and polysomnographical features of RBD, both of whom proved to have previously undiagnosed narcolepsy. Whilst the association of narcolepsy with RBD has been previously recognised, this is the first report of narcoleptic patients presenting with RBD. Narcolepsy should be included in the differential diagnosis of young patients presenting with abnormal behaviour during sleep compatible with RBD. PMID:18343568

  15. Using the Model Coupling Toolkit to couple earth system models

    USGS Publications Warehouse

    Warner, J.C.; Perlin, N.; Skyllingstad, E.D.

    2008-01-01

    Continued advances in computational resources are providing the opportunity to operate more sophisticated numerical models. Additionally, there is an increasing demand for multidisciplinary studies that include interactions between different physical processes. Therefore there is a strong desire to develop coupled modeling systems that utilize existing models and allow efficient data exchange and model control. The basic system would entail model "1" running on "M" processors and model "2" running on "N" processors, with efficient exchange of model fields at predetermined synchronization intervals. Here we demonstrate two coupled systems: the coupling of the ocean circulation model Regional Ocean Modeling System (ROMS) to the surface wave model Simulating WAves Nearshore (SWAN), and the coupling of ROMS to the atmospheric model Coupled Ocean Atmosphere Prediction System (COAMPS). Both coupled systems use the Model Coupling Toolkit (MCT) as a mechanism for operation control and inter-model distributed memory transfer of model variables. In this paper we describe requirements and other options for model coupling, explain the MCT library, ROMS, SWAN and COAMPS models, methods for grid decomposition and sparse matrix interpolation, and provide an example from each coupled system. Methods presented in this paper are clearly applicable for coupling of other types of models. ?? 2008 Elsevier Ltd. All rights reserved.

  16. Staff reactions to challenging behaviour: an observation study.

    PubMed

    Lambrechts, Greet; Van Den Noortgate, Wim; Eeman, Lieve; Maes, Bea

    2010-01-01

    Staff reactions play an important role in the development and maintaining of clients' challenging behaviour. Because there is a paucity of research on staff reactions in naturalistic settings, this study examined sequential associations between challenging behaviour and staff reactions by means of a descriptive analysis. We analysed video recordings of the reactions of 10 staff members towards challenging behaviour of clients with severe or profound intellectual disabilities who displayed self-injurious behaviour, stereotyped behaviour and/or aggressive/destructive behaviour. As expected, the staff members used much verbal behaviours after challenging behaviour and often immediately tried to stop the challenging behaviour. Furthermore, staff often gave attention to challenging behaviour whereas offering or taking away material or tasks were less frequently observed reactions. Reactions to aggressive/destructive behaviour and self-injurious behaviour were quite similar. After stereotyped behaviour, not that many reactions occurred significantly more. Although this study has clinical implications and made a valuable contribution to research on staff reactions to challenging behaviour, more research is needed, more specifically, about the effectiveness of these staff reactions.

  17. Fractal analysis of behaviour in a wild primate: behavioural complexity in health and disease.

    PubMed

    Macintosh, Andrew J J; Alados, Concepción L; Huffman, Michael A

    2011-10-01

    Parasitism and other stressors are ubiquitous in nature but their effects on animal behaviour can be difficult to identify. We investigated the effects of nematode parasitism and other indicators of physiological impairment on the sequential complexity of foraging and locomotion behaviour among wild Japanese macaques (Macaca fuscata yakui). We observed all sexually mature individuals (n = 28) in one macaque study group between October 2007 and August 2008, and collected two faecal samples/month/individual (n = 362) for parasitological examination. We used detrended fluctuation analysis (DFA) to investigate long-range autocorrelation in separate, binary sequences of foraging (n = 459) and locomotion (n = 446) behaviour collected via focal sampling. All behavioural sequences exhibited long-range autocorrelation, and linear mixed-effects models suggest that increasing infection with the nodular worm Oesophagostomum aculeatum, clinically impaired health, reproductive activity, ageing and low dominance status were associated with reductions in the complexity of locomotion, and to a lesser extent foraging, behaviour. Furthermore, the sequential complexity of behaviour increased with environmental complexity. We argue that a reduction in complexity in animal behaviour characterizes individuals in impaired or 'stressed' states, and may have consequences if animals cannot cope with heterogeneity in their natural habitats.

  18. Online sexual behaviours among Swedish youth: associations to background factors, behaviours and abuse.

    PubMed

    Jonsson, Linda S; Bladh, Marie; Priebe, Gisela; Svedin, Carl Göran

    2015-10-01

    Sexual activity online may result in positive experiences for young people, or lead them to engage in risky behaviours possibly resulting in sexual assault or abuse. The aim of our study was to investigate associations between online sexual behaviours among Swedish youth and background factors as well as aspects of well-being. The behaviours investigated were: having sex online with a contact met online, having sex with an online contact offline, posting sexual pictures online, and selling sex online. We used data from a representative sample of 3,432 Swedish youth who were asked about their lifetime experiences as well as their experiences within the previous year. We hypothesized that more advanced online sexual behaviours were associated with more problematic background factors, worse psychosocial well-being and riskier behaviours in general. Bivariate relationships were evaluated followed by a multiple logistic regression model. Our data suggested that most Swedish youth do not perform any of the assessed online sexual behaviours. Young people who reported online sexual behaviour showed a more problematic background, rated their health as poorer, had a more sexualized life and had experienced more sexual or physical abuse. Professionals who work with young people need to help them better evaluate potential risks online and offer support when needed. Youths who sell sex online are especially at risk and need extra attention, as they might be in greater need of protection and therapeutic support.

  19. Blood donation and Ajzen's theory of planned behaviour: an examination of perceived behavioural control.

    PubMed

    Giles, M; Cairns, E

    1995-06-01

    In spite of the success achieved by the theory of reasoned action, researchers continue to suggest that new components should be added to the original model. Indeed, Ajzen has himself acknowledged that some behaviours may be subject to control problems and thus proposed the theory of planned behaviour to handle behaviours of this kind. This study set out to explore the predictive superiority of the revised theory of planned behaviour by focusing on blood donation, a behavioural domain in which volitional control was thought to be incomplete. It was also the intention to explore the extent to which the belief-based measure of attitude exists as a multidimensional construct. An Ajzen & Fishbein type questionnaire was administered to 141 undergraduate students. Multiple regression analyses provided strong support for the theory of planned behaviour, suggesting that perception of control has an important impact on a person's behavioural motivation. Also, some support for a multidimensional representation of the belief-based measure of attitude was provided.

  20. Blood donation and Ajzen's theory of planned behaviour: an examination of perceived behavioural control.

    PubMed

    Giles, M; Cairns, E

    1995-06-01

    In spite of the success achieved by the theory of reasoned action, researchers continue to suggest that new components should be added to the original model. Indeed, Ajzen has himself acknowledged that some behaviours may be subject to control problems and thus proposed the theory of planned behaviour to handle behaviours of this kind. This study set out to explore the predictive superiority of the revised theory of planned behaviour by focusing on blood donation, a behavioural domain in which volitional control was thought to be incomplete. It was also the intention to explore the extent to which the belief-based measure of attitude exists as a multidimensional construct. An Ajzen & Fishbein type questionnaire was administered to 141 undergraduate students. Multiple regression analyses provided strong support for the theory of planned behaviour, suggesting that perception of control has an important impact on a person's behavioural motivation. Also, some support for a multidimensional representation of the belief-based measure of attitude was provided. PMID:7620844

  1. Oxidative stress, activity behaviour and body mass in captive parrots.

    PubMed

    Larcombe, S D; Tregaskes, C A; Coffey, J; Stevenson, A E; Alexander, L G; Arnold, K E

    2015-01-01

    Many parrot species are kept in captivity for conservation, but often show poor reproduction, health and survival. These traits are known to be influenced by oxidative stress, the imbalance between the production of reactive oxygen species (ROS) and ability of antioxidant defences to ameliorate ROS damage. In humans, oxidative stress is linked with obesity, lack of exercise and poor nutrition, all of which are common in captive animals. Here, we tested whether small parrots (budgerigars, Melopsittacus undulatus) maintained in typical pet cages and on ad libitum food varied in oxidative profile, behaviour and body mass. Importantly, as with many birds held in captivity, they did not have enough space to engage in extensive free flight. Four types of oxidative damage, single-stranded DNA breaks (low-pH comet assay), alkali-labile sites in DNA (high-pH comet assay), sensitivity of DNA to ROS (H2O2-treated comet assay) and malondialdehyde (a byproduct of lipid peroxidation), were uncorrelated with each other and with plasma concentrations of dietary antioxidants. Without strenuous exercise over 28 days in a relatively small cage, more naturally 'active' individuals had more single-stranded DNA breaks than sedentary birds. High body mass at the start or end of the experiment, coupled with substantial mass gain, were all associated with raised sensitivity of DNA to ROS. Thus, high body mass in these captive birds was associated with oxidative damage. These birds were not lacking dietary antioxidants, because final body mass was positively related to plasma levels of retinol, zeaxanthin and α-tocopherol. Individuals varied widely in activity levels, feeding behaviour, mass gain and oxidative profile despite standardized living conditions. DNA damage is often associated with poor immunocompetence, low fertility and faster ageing. Thus, we have candidate mechanisms for the limited lifespan and fecundity common to many birds kept for conservation purposes.

  2. Oxidative stress, activity behaviour and body mass in captive parrots.

    PubMed

    Larcombe, S D; Tregaskes, C A; Coffey, J; Stevenson, A E; Alexander, L G; Arnold, K E

    2015-01-01

    Many parrot species are kept in captivity for conservation, but often show poor reproduction, health and survival. These traits are known to be influenced by oxidative stress, the imbalance between the production of reactive oxygen species (ROS) and ability of antioxidant defences to ameliorate ROS damage. In humans, oxidative stress is linked with obesity, lack of exercise and poor nutrition, all of which are common in captive animals. Here, we tested whether small parrots (budgerigars, Melopsittacus undulatus) maintained in typical pet cages and on ad libitum food varied in oxidative profile, behaviour and body mass. Importantly, as with many birds held in captivity, they did not have enough space to engage in extensive free flight. Four types of oxidative damage, single-stranded DNA breaks (low-pH comet assay), alkali-labile sites in DNA (high-pH comet assay), sensitivity of DNA to ROS (H2O2-treated comet assay) and malondialdehyde (a byproduct of lipid peroxidation), were uncorrelated with each other and with plasma concentrations of dietary antioxidants. Without strenuous exercise over 28 days in a relatively small cage, more naturally 'active' individuals had more single-stranded DNA breaks than sedentary birds. High body mass at the start or end of the experiment, coupled with substantial mass gain, were all associated with raised sensitivity of DNA to ROS. Thus, high body mass in these captive birds was associated with oxidative damage. These birds were not lacking dietary antioxidants, because final body mass was positively related to plasma levels of retinol, zeaxanthin and α-tocopherol. Individuals varied widely in activity levels, feeding behaviour, mass gain and oxidative profile despite standardized living conditions. DNA damage is often associated with poor immunocompetence, low fertility and faster ageing. Thus, we have candidate mechanisms for the limited lifespan and fecundity common to many birds kept for conservation purposes. PMID:27293729

  3. Aging and response conflict solution: Behavioural and functional connectivity changes

    PubMed Central

    Cieslik, Edna C.; Behrwind, Simone D.; Roski, Christian; Caspers, Svenja; Amunts, Katrin; Eickhoff, Simon B.

    2014-01-01

    Healthy aging has been found associated with less efficient response conflict solution, but the cognitive and neural mechanisms remain elusive. In a two-experiment study, we first examined the behavioural consequences of this putative age-related decline for conflicts induced by spatial stimulus–response incompatibility. We then used resting-state functional magnetic resonance imaging data from a large, independent sample of adults (n = 399; 18–85 years) to investigate age differences in functional connectivity between the nodes of a network previously found associated with incompatibility-induced response conflicts in the very same paradigm. As expected, overcoming interference from conflicting response tendencies took longer in older adults, even after accounting for potential mediator variables (general response speed and accuracy, motor speed, visuomotor coordination ability, and cognitive flexibility). Experiment 2 revealed selective age-related decreases in functional connectivity between bilateral anterior insula, pre-supplementary motor area, and right dorsolateral prefrontal cortex. Importantly, these age effects persisted after controlling for regional gray-matter atrophy assessed by voxel-based morphometry. Meta-analytic functional profiling using the BrainMap database showed these age-sensitive nodes to be more strongly linked to highly abstract cognition, as compared with the remaining network nodes, which in turn were more strongly linked to action-related processing. These findings indicate changes in interregional coupling with age among task-relevant network nodes that are not specifically associated with conflict resolution per se. Rather, our behavioural and neural data jointly suggest that healthy aging is associated with difficulties in properly activating non-dominant but relevant task schemata necessary to exert efficient cognitive control over action. PMID:24718622

  4. Oxidative stress, activity behaviour and body mass in captive parrots

    PubMed Central

    Larcombe, S. D.; Tregaskes, C. A.; Coffey, J.; Stevenson, A. E.; Alexander, L. G.; Arnold, K. E.

    2015-01-01

    Many parrot species are kept in captivity for conservation, but often show poor reproduction, health and survival. These traits are known to be influenced by oxidative stress, the imbalance between the production of reactive oxygen species (ROS) and ability of antioxidant defences to ameliorate ROS damage. In humans, oxidative stress is linked with obesity, lack of exercise and poor nutrition, all of which are common in captive animals. Here, we tested whether small parrots (budgerigars, Melopsittacus undulatus) maintained in typical pet cages and on ad libitum food varied in oxidative profile, behaviour and body mass. Importantly, as with many birds held in captivity, they did not have enough space to engage in extensive free flight. Four types of oxidative damage, single-stranded DNA breaks (low-pH comet assay), alkali-labile sites in DNA (high-pH comet assay), sensitivity of DNA to ROS (H2O2-treated comet assay) and malondialdehyde (a byproduct of lipid peroxidation), were uncorrelated with each other and with plasma concentrations of dietary antioxidants. Without strenuous exercise over 28 days in a relatively small cage, more naturally ‘active’ individuals had more single-stranded DNA breaks than sedentary birds. High body mass at the start or end of the experiment, coupled with substantial mass gain, were all associated with raised sensitivity of DNA to ROS. Thus, high body mass in these captive birds was associated with oxidative damage. These birds were not lacking dietary antioxidants, because final body mass was positively related to plasma levels of retinol, zeaxanthin and α-tocopherol. Individuals varied widely in activity levels, feeding behaviour, mass gain and oxidative profile despite standardized living conditions. DNA damage is often associated with poor immunocompetence, low fertility and faster ageing. Thus, we have candidate mechanisms for the limited lifespan and fecundity common to many birds kept for conservation purposes. PMID

  5. Anisotropic cubic curvature couplings

    NASA Astrophysics Data System (ADS)

    Bailey, Quentin G.

    2016-09-01

    To complement recent work on tests of spacetime symmetry in gravity, cubic curvature couplings are studied using an effective field theory description of spacetime-symmetry breaking. The associated mass-dimension-eight coefficients for Lorentz violation studied do not result in any linearized gravity modifications and instead are revealed in the first nonlinear terms in an expansion of spacetime around a flat background. We consider effects on gravitational radiation through the energy loss of a binary system and we study two-body orbital perturbations using the post-Newtonian metric. Some effects depend on the internal structure of the source and test bodies, thereby breaking the weak equivalence principle for self-gravitating bodies. These coefficients can be measured in Solar-System tests, while binary-pulsar systems and short-range gravity tests are particularly sensitive.

  6. Coupled quantum Otto cycle.

    PubMed

    Thomas, George; Johal, Ramandeep S

    2011-03-01

    We study the one-dimensional isotropic Heisenberg model of two spin-1/2 systems as a quantum heat engine. The engine undergoes a four-step Otto cycle where the two adiabatic branches involve changing the external magnetic field at a fixed value of the coupling constant. We find conditions for the engine efficiency to be higher than in the uncoupled model; in particular, we find an upper bound which is tighter than the Carnot bound. A domain of parameter values is pointed out which was not feasible in the interaction-free model. Locally, each spin seems to cause a flow of heat in a direction opposite to the global temperature gradient. This feature is explained by an analysis of the local effective temperature of the spins.

  7. Cooking strongly coupled plasmas

    NASA Astrophysics Data System (ADS)

    Clérouin, Jean

    2015-09-01

    We present the orbital-free method for dense plasmas which allows for efficient variable ionisation molecular dynamics. This approach is a literal application of density functional theory where the use of orbitals is bypassed by a semi-classical estimation of the electron kinetic energy through the Thomas-Fermi theory. Thanks to a coherent definition of ionisation, we evidence a particular regime in which the static structure no longer depends on the temperature: the Γ-plateau. With the help of the well-known Thomas-Fermi scaling laws, we derive the conditions required to obtain a plasma at a given value of the coupling parameter and deduce useful fits. Static and dynamical properties are predicted as well as a a simple equation of state valid on the Γ-plateau. We show that the one component plasma model can be helpful to describe the correlations in real systems.

  8. Quartic gauge boson couplings

    NASA Astrophysics Data System (ADS)

    He, Hong-Jian

    1998-08-01

    We review the recent progress in studying the anomalous electroweak quartic gauge boson couplings (QGBCs) at the LHC and the next generation high energy e±e- linear colliders (LCs). The main focus is put onto the strong electroweak symmetry breaking scenario in which the non-decoupling guarantees sizable new physics effects for the QGBCs. After commenting upon the current low energy indirect bounds and summarizing the theoretical patterns of QGBCs predicted by the typical resonance/non-resonance models, we review our systematic model-independent analysis on bounding them via WW-fusion and WWZ/ZZZ-production. The interplay of the two production mechanisms and the important role of the beam-polarization at the LCs are emphasized. The same physics may be similarly and better studied at a multi-TeV muon collider with high luminosity.

  9. The behaviour change wheel: A new method for characterising and designing behaviour change interventions

    PubMed Central

    2011-01-01

    Background Improving the design and implementation of evidence-based practice depends on successful behaviour change interventions. This requires an appropriate method for characterising interventions and linking them to an analysis of the targeted behaviour. There exists a plethora of frameworks of behaviour change interventions, but it is not clear how well they serve this purpose. This paper evaluates these frameworks, and develops and evaluates a new framework aimed at overcoming their limitations. Methods A systematic search of electronic databases and consultation with behaviour change experts were used to identify frameworks of behaviour change interventions. These were evaluated according to three criteria: comprehensiveness, coherence, and a clear link to an overarching model of behaviour. A new framework was developed to meet these criteria. The reliability with which it could be applied was examined in two domains of behaviour change: tobacco control and obesity. Results Nineteen frameworks were identified covering nine intervention functions and seven policy categories that could enable those interventions. None of the frameworks reviewed covered the full range of intervention functions or policies, and only a minority met the criteria of coherence or linkage to a model of behaviour. At the centre of a proposed new framework is a 'behaviour system' involving three essential conditions: capability, opportunity, and motivation (what we term the 'COM-B system'). This forms the hub of a 'behaviour change wheel' (BCW) around which are positioned the nine intervention functions aimed at addressing deficits in one or more of these conditions; around this are placed seven categories of policy that could enable those interventions to occur. The BCW was used reliably to characterise interventions within the English Department of Health's 2010 tobacco control strategy and the National Institute of Health and Clinical Excellence's guidance on reducing obesity

  10. Nonminimally coupled hybrid inflation

    SciTech Connect

    Koh, Seoktae; Minamitsuji, Masato

    2011-02-15

    We discuss the hybrid inflation model where the inflaton field is nonminimally coupled to gravity. In the Jordan frame, the potential contains {phi}{sup 4} term as well as terms in the original hybrid inflation model. In our model, inflation can be classified into the type (I) and the type (II). In the type (I), inflation is terminated by the tachyonic instability of the waterfall field, while in the type (II) by the violation of slow-roll conditions. In our model, the reheating takes place only at the true minimum and even in the case (II) finally the tachyonic instability occurs after the termination of inflation. For a negative nonminimal coupling, inflation takes place in the vacuum-dominated region, in the large field region, or near the local minimum/maximum. Inflation in the vacuum-dominated region becomes either the type (I) or (II), resulting in a blue or red spectrum of the curvature perturbations, respectively. Inflation around the local maximum can be either the type (I) or the type (II), which results in the red spectrum of the curvature perturbations, while around the local minimum it must be the type (I), which results in the blue spectrum. In the large field region, to terminate inflation, potential in the Einstein frame must be positively tilted, always resulting in the red spectrum. We then numerically solve the equations of motion to investigate the whole dynamics of inflaton and confirm that the spectrum of curvature perturbations changes from red to blue ones as scales become smaller.

  11. Addressing challenging behaviour in children with Down syndrome: the use of applied behaviour analysis for assessment and intervention.

    PubMed

    Feeley, Kathleen M; Jones, Emily A

    2006-09-01

    Children with Down syndrome are at an increased risk for engaging in challenging behaviour that may be part of a behavioural phenotype characteristic of Down syndrome. The methodology of applied behaviour analysis has been demonstrated effective with a wide range of challenging behaviours, across various disabilities. Applications to children with Down syndrome and the examination of behaviourally based strategies to specifically address the unique characteristics of children with Down syndrome are limited. However, there are several studies in which a subset of the participants did have Down syndrome. A handful of these studies are reviewed within the context of functional behaviour assessment and Positive Behavioural Supports. Drawing from these studies and the behavioural literature, as well as the authors' clinical experience and research, suggestions regarding early intervention for challenging behaviour with children with Down syndrome are provided.

  12. Multistable internal resonance in electroelastic crystals with nonlinearly coupled modes.

    PubMed

    Kirkendall, Christopher R; Kwon, Jae W

    2016-01-01

    Nonlinear modal interactions have recently become the focus of intense research in micro- and nanoscale resonators for their use to improve oscillator performance and probe the frontiers of fundamental physics. However, our understanding of modal coupling is largely restricted to clamped-clamped beams, and lacking in systems with both geometric and material nonlinearities. Here we report multistable energy transfer between internally resonant modes of an electroelastic crystal plate and use a mixed analytical-numerical approach to provide new insight into these complex interactions. Our results reveal a rich bifurcation structure marked by nested regions of multistability. Even the simple case of two coupled modes generates a host of topologically distinct dynamics over the parameter space, ranging from the usual Duffing bistability to complex multistable behaviour and quasiperiodic motion.

  13. Multistable internal resonance in electroelastic crystals with nonlinearly coupled modes.

    PubMed

    Kirkendall, Christopher R; Kwon, Jae W

    2016-01-01

    Nonlinear modal interactions have recently become the focus of intense research in micro- and nanoscale resonators for their use to improve oscillator performance and probe the frontiers of fundamental physics. However, our understanding of modal coupling is largely restricted to clamped-clamped beams, and lacking in systems with both geometric and material nonlinearities. Here we report multistable energy transfer between internally resonant modes of an electroelastic crystal plate and use a mixed analytical-numerical approach to provide new insight into these complex interactions. Our results reveal a rich bifurcation structure marked by nested regions of multistability. Even the simple case of two coupled modes generates a host of topologically distinct dynamics over the parameter space, ranging from the usual Duffing bistability to complex multistable behaviour and quasiperiodic motion. PMID:26961749

  14. Multistable internal resonance in electroelastic crystals with nonlinearly coupled modes

    NASA Astrophysics Data System (ADS)

    Kirkendall, Christopher R.; Kwon, Jae W.

    2016-03-01

    Nonlinear modal interactions have recently become the focus of intense research in micro- and nanoscale resonators for their use to improve oscillator performance and probe the frontiers of fundamental physics. However, our understanding of modal coupling is largely restricted to clamped-clamped beams, and lacking in systems with both geometric and material nonlinearities. Here we report multistable energy transfer between internally resonant modes of an electroelastic crystal plate and use a mixed analytical-numerical approach to provide new insight into these complex interactions. Our results reveal a rich bifurcation structure marked by nested regions of multistability. Even the simple case of two coupled modes generates a host of topologically distinct dynamics over the parameter space, ranging from the usual Duffing bistability to complex multistable behaviour and quasiperiodic motion.

  15. Multistable internal resonance in electroelastic crystals with nonlinearly coupled modes

    PubMed Central

    Kirkendall, Christopher R.; Kwon, Jae W.

    2016-01-01

    Nonlinear modal interactions have recently become the focus of intense research in micro- and nanoscale resonators for their use to improve oscillator performance and probe the frontiers of fundamental physics. However, our understanding of modal coupling is largely restricted to clamped-clamped beams, and lacking in systems with both geometric and material nonlinearities. Here we report multistable energy transfer between internally resonant modes of an electroelastic crystal plate and use a mixed analytical-numerical approach to provide new insight into these complex interactions. Our results reveal a rich bifurcation structure marked by nested regions of multistability. Even the simple case of two coupled modes generates a host of topologically distinct dynamics over the parameter space, ranging from the usual Duffing bistability to complex multistable behaviour and quasiperiodic motion. PMID:26961749

  16. The epidemiology of bacterial vaginosis in relation to sexual behaviour

    PubMed Central

    2010-01-01

    Background Bacterial vaginosis (BV) has been most consistently linked to sexual behaviour, and the epidemiological profile of BV mirrors that of established sexually transmitted infections (STIs). It remains a matter of debate however whether BV pathogenesis does actually involve sexual transmission of pathogenic micro-organisms from men to women. We therefore made a critical appraisal of the literature on BV in relation to sexual behaviour. Discussion G. vaginalis carriage and BV occurs rarely with children, but has been observed among adolescent, even sexually non-experienced girls, contradicting that sexual transmission is a necessary prerequisite to disease acquisition. G. vaginalis carriage is enhanced by penetrative sexual contact but also by non-penetrative digito-genital contact and oral sex, again indicating that sex per se, but not necessarily coital transmission is involved. Several observations also point at female-to-male rather than at male-to-female transmission of G. vaginalis, presumably explaining the high concordance rates of G. vaginalis carriage among couples. Male antibiotic treatment has not been found to protect against BV, condom use is slightly protective, whereas male circumcision might protect against BV. BV is also common among women-who-have-sex-with-women and this relates at least in part to non-coital sexual behaviours. Though male-to-female transmission cannot be ruled out, overall there is little evidence that BV acts as an STD. Rather, we suggest BV may be considered a sexually enhanced disease (SED), with frequency of intercourse being a critical factor. This may relate to two distinct pathogenetic mechanisms: (1) in case of unprotected intercourse alkalinisation of the vaginal niche enhances a shift from lactobacilli-dominated microflora to a BV-like type of microflora and (2) in case of unprotected and protected intercourse mechanical transfer of perineal enteric bacteria is enhanced by coitus. A similar mechanism of mechanical

  17. Simulation of curving behaviour under high traction in lubricated wheel-rail contacts

    NASA Astrophysics Data System (ADS)

    Arias-Cuevas, Oscar; Li, Zili; Popovici, Radu I.; Schipper, Dik J.

    2010-12-01

    Migration of the flange lubricant to the top of the high rail may compromise the traction of a rail vehicle and affect its curving behaviour. In order to simulate this possible situation, a lubrication model has been coupled to commercial multi-body dynamics software to describe the tangential formulation of the lubricated high-rail contact. Different friction levels have been adopted for the low rail to study their influence on the curving behaviour and traction. Since the creep force in the wheel-rail contact approaches saturation of the friction, the traction control unit of the rail vehicle under study has also been modelled to account for the reduction of the wheel axle torque in the presence of wheel macro-slip.

  18. A new nonlinear model for analyzing the behaviour of carbon nanotube-based resonators

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

    The present study develops a new size-dependent nonlinear model for the analysis of the behaviour of carbon nanotube-based resonators. In particular, based on modified couple stress theory, the fully nonlinear equations of motion of the carbon nanotube-based resonator are derived using Hamilton's principle, taking into account both the longitudinal and transverse displacements. Molecular dynamics simulation is then performed in order to verify the validity of the developed size-dependent continuum model at the nano scale. The nonlinear partial differential equations of motion of the system are discretized by means of the Galerkin technique, resulting in a high-dimensional reduced-order model of the system. The pseudo-arclength continuation technique is employed to examine the nonlinear resonant behaviour of the carbon nanotube-based resonator. A new universal pull-in formula is also developed for predicting the occurrence of the static pull-in and validated using numerical simulations.

  19. Extending Social Cognition Models of Health Behaviour

    ERIC Educational Resources Information Center

    Abraham, Charles; Sheeran, Paschal; Henderson, Marion

    2011-01-01

    A cross-sectional study assessed the extent to which indices of social structure, including family socio-economic status (SES), social deprivation, gender and educational/lifestyle aspirations correlated with adolescent condom use and added to the predictive utility of a theory of planned behaviour model. Analyses of survey data from 824 sexually…

  20. Characterizing behavioural 'characters': an evolutionary framework.

    PubMed

    Araya-Ajoy, Yimen G; Dingemanse, Niels J

    2014-02-01

    Biologists often study phenotypic evolution assuming that phenotypes consist of a set of quasi-independent units that have been shaped by selection to accomplish a particular function. In the evolutionary literature, such quasi-independent functional units are called 'evolutionary characters', and a framework based on evolutionary principles has been developed to characterize them. This framework mainly focuses on 'fixed' characters, i.e. those that vary exclusively between individuals. In this paper, we introduce multi-level variation and thereby expand the framework to labile characters, focusing on behaviour as a worked example. We first propose a concept of 'behavioural characters' based on the original evolutionary character concept. We then detail how integration of variation between individuals (cf. 'personality') and within individuals (cf. 'individual plasticity') into the framework gives rise to a whole suite of novel testable predictions about the evolutionary character concept. We further propose a corresponding statistical methodology to test whether observed behaviours should be considered expressions of a hypothesized evolutionary character. We illustrate the application of our framework by characterizing the behavioural character 'aggressiveness' in wild great tits, Parus major.

  1. Offending Behaviour in Adults with Asperger Syndrome

    ERIC Educational Resources Information Center

    Allen, David; Evans, Carys; Hider, Andrew; Hawkins, Sarah; Peckett, Helen; Morgan, Hugh

    2008-01-01

    Considerable speculation is evident both within the scientific literature and popular media regarding possible links between Asperger syndrome and offending. A survey methodology that utilised quantitative data collection was employed to investigate the prevalence of offending behaviour amongst adults with Asperger Syndrome in a large geographical…

  2. Mobility Attitudes and Behaviours among Young Europeans

    ERIC Educational Resources Information Center

    Doherty, Noeleen; Dickmann, Michael; Mills, Timothy

    2010-01-01

    Purpose: The paper seeks to explore the career attitudes, motivations and behaviours of young people in initial vocational education and training (IVET) in Europe. Design/methodology/approach: This exploratory web-based survey was conducted during the European year for mobility. Drawing on existing research on the motivators of international…

  3. Behavioural biology of Chagas disease vectors

    PubMed Central

    Lazzari, Claudio Ricardo; Pereira, Marcos Horácio; Lorenzo, Marcelo Gustavo

    2013-01-01

    Many arthropod species have adopted vertebrate blood as their main food source. Blood is rich in nutrients and, except for the presence of parasites, sterile. However, this food source is not freely available, nor is obtaining it devoid of risk. It circulates inside vessels hidden underneath the skin of mobile hosts that are able to defend themselves and even predate the insects that try to feed on them. Thus, the haematophagous lifestyle is associated with major morphological, physiological and behavioural adaptations that have accumulated throughout the evolutionary history of the various lineages of blood-sucking arthropods. These adaptations have significant consequences for the evolution of parasites as well as for the epidemiology of vector-transmitted diseases. In this review article, we analyse various aspects of the behaviour of triatomine bugs to illustrate how each behavioural trait represents a particular adaptation to their close association with their hosts, which may easily turn into predators. Our aim is to offer to the reader an up-to-date integrative perspective on the behaviour of Chagas disease vectors and to propose new research avenues to encourage both young and experienced colleagues to explore this aspect of triatomine biology. PMID:24473801

  4. Bullying Behaviour, Intentions and Classroom Ecology

    ERIC Educational Resources Information Center

    Pryce, Sarah; Frederickson, Norah

    2013-01-01

    Anti-bullying commitment across school communities is seen as crucial to the effectiveness of interventions. This exploratory study used a mixed-methods design to investigate bullying behaviour, intentions and aspects of the classroom ecology within the context of an anti-bullying initiative that was launched with a declaration of commitment.…

  5. Affect, Behavioural Schemas and the Proving Process

    ERIC Educational Resources Information Center

    Selden, Annie; McKee, Kerry; Selden, John

    2010-01-01

    In this largely theoretical article, we discuss the relation between a kind of affect, behavioural schemas and aspects of the proving process. We begin with affect as described in the mathematics education literature, but soon narrow our focus to a particular kind of affect--nonemotional cognitive feelings. We then mention the position of feelings…

  6. Abnormal Repetitive Behaviours: Shared Phenomenology and Pathophysiology

    ERIC Educational Resources Information Center

    Muehlmann, A. M.; Lewis, M. H.

    2012-01-01

    Background: Self-injurious behaviour (SIB) is a devastating problem observed in individuals with various neurodevelopmental disorders, including specific genetic syndromes as well as idiopathic intellectual and developmental disability. Although an increased prevalence of SIB has been documented in specific genetic mutations, little is known about…

  7. Current Developments in Measuring Academic Behavioural Confidence

    ERIC Educational Resources Information Center

    Sander, Paul

    2009-01-01

    Using published findings and by further analyses of existing data, the structure, validity and utility of the Academic Behavioural Confidence scale (ABC) is critically considered. Validity is primarily assessed through the scale's relationship with other existing scales as well as by looking for predicted differences. The utility of the ABC scale…

  8. Sleepwalking and other ambulatory behaviours during sleep.

    PubMed

    Plazzi, G; Vetrugno, R; Provini, F; Montagna, P

    2005-12-01

    Different pathological conditions may lead to somnambulic automatisms arising from nocturnal sleep. Video polysomnography represents the diagnostic tool but, due to the difficulty of capturing complex episodes in the sleep laboratory, audio-video recordings at home of the episodes may help in the differential diagnosis also. Sleepwalking is a disorder of arousal in which the subject arises from deep sleep, even displaying long complex behaviour, including leaving the bed and walking, with memory impairment of the event. Disordered arousal mechanisms with an inability of the brain to fully awaken from slow-wave sleep are thought to lead to these motor automatisms. REM sleep behaviour disorders begin during REM sleep and are accompanied by features of REM sleep. The motor behaviour may be violent and injurious to the patient and/or bed partner. In some patients, however, the behaviour may be similar to that observed in sleepwalking and some patients have an overlap syndrome. In nocturnal frontal lobe epilepsy in particular, and in complex partial seizures in general, stereotypic and repetitive motor attacks may recur, at any time, on the same night and on different nights, with a continuum between minimal or minor attacks and major or prolonged episodes up to agitated epileptic nocturnal wanderings. PMID:16331395

  9. Coexisting Problem Behaviour in Severe Dyslexia

    ERIC Educational Resources Information Center

    Dahle, Anne Elisabeth; Knivsberg, Ann-Mari; Andreassen, Anne Brit

    2011-01-01

    A small group of children and young adolescent with dyslexia has severely impaired reading skills despite prolonged special education. These are the students in focus. In dyslexia, problem behaviour, internalised as well as externalised, has previously been reported, so also for the participants with dyslexia in this study. The aim of the present…

  10. Testing the Fracture Behaviour of Chocolate

    ERIC Educational Resources Information Center

    Parsons, L. B.; Goodall, R.

    2011-01-01

    In teaching the materials science aspects of physics, mechanical behaviour is important due to its relevance to many practical applications. This article presents a method for experimentally examining the toughness of chocolate, including a design for a simple test rig, and a number of experiments that can be performed in the classroom. Typical…

  11. Behavioural Phenotypes in Disability Research: Historical Perspectives

    ERIC Educational Resources Information Center

    Goodey, C. F.

    2006-01-01

    Western medicine has a long history of accounting for behaviour by reducing the body to ultimate explanatory entities. In pre-modern medicine these were invisible "animal spirits" circulating the body. In modern medicine, they are "genes". Both raise questions. The psychological phenotype is defined by human consensus, varying according to time…

  12. School Phobia: Understanding a Complex Behavioural Response

    ERIC Educational Resources Information Center

    Chitiyo, Morgan; Wheeler, John J.

    2006-01-01

    School phobia affects about 5% of the school-age population. If left untreated, school phobia can have devastating long-term consequences in children challenged by this condition. Various treatment approaches have been used to explore this complex behavioural response, major among them being the psychoanalytic, psychodynamic, pharmacological and…

  13. The Pedestrian Behaviour of Spanish Adolescents

    ERIC Educational Resources Information Center

    Sullman, M. J. M.; Gras, M. E.; Font-Mayolas, S.; Masferrer, L.; Cunill, M.; Planes, M.

    2011-01-01

    Adolescent pedestrians are a particularly vulnerable group of road users. This research tested the applicability of the recently developed Adolescent Road user Behaviour Questionnaire (ARBQ) amongst a sample of 2006 Spanish adolescents. Confirmatory Factor Analysis of the full scale found that the original three factors did not adequately fit the…

  14. Consumer behaviours: Teaching children to save energy

    NASA Astrophysics Data System (ADS)

    Grønhøj, Alice

    2016-08-01

    Energy-saving programmes are increasingly targeted at children to encourage household energy conservation. A study involving the assignment of energy-saving interventions to Girl Scouts shows that a child-focused intervention can improve energy-saving behaviours among children and their parents.

  15. Supervisor Behaviours that Facilitate Training Transfer

    ERIC Educational Resources Information Center

    Lancaster, Sue; Di Milia, Lee; Cameron, Roslyn

    2013-01-01

    Purpose: The purpose of this paper is to describe the supervisor behaviours that employees found to be helpful and unhelpful in facilitating training transfer. The study aims to provide rich qualitative data from the employee's perspective. Design/methodology/approach: This study utilises a cross-sectional design. A case study and a qualitative…

  16. Opiate antagonists stimulate affiliative behaviour in monkeys.

    PubMed

    Fabre-Nys, C; Meller, R E; Keverne, E B

    1982-04-01

    The effects of treating captive talapoin monkeys acutely (twice daily for 7 days) with naltrexone hydrochloride (0.25 mg 0.5 mg and 1 mg/kg intramuscular injections twice daily), naloxone hydrochloride (0.5 mg/kg IM twice daily) and sulpiride (1.5 mg/kg IM twice daily) was studied in social pairs and singly caged animals. The behaviour of social pairs and endocrine changes in all treated monkeys were monitored before, during and after withdrawal of the course of drug treatment. Naltrexone and naloxone, but not sulpiride, significant increased grooming and grooming invitations while aggressive behaviour, self grooming, scratching and general locomotor activity were unaffected. There was an overall increase in LH, testosterone and cortisol in plasma samples taken 60 mins after opiate receptor blockade. Prolactin was unchanged but increased dramatically in animals treated with sulpiride. No significant endocrine changes were observed to precede the increased grooming behaviour which opiate receptor blockade induced. The behavioural changes reported for this primate support the view that positive affect arising from social bonds may be mediated by cerebral endorphin containing systems. PMID:6280208

  17. Behaviour Assessment in Ontario Mathematics Classrooms

    ERIC Educational Resources Information Center

    Miller, Tess; Klinger, D.; Shulha, L.

    2006-01-01

    Curriculum reform in Ontario secondary schools proposed that the assessment of student achievement be separated into academic achievement and non-academic achievement or the behaviours that can influence academic achievement. The purpose of this study was to explore teachers' assessment practices of non-academic achievement in Ontario' s grade 9…

  18. Bullying and Inappropriate Behaviour among Faculty Personnel

    ERIC Educational Resources Information Center

    Meriläinen, Matti; Sinkkonen, Hanna-Maija; Puhakka, Helena; Käyhkö, Katinka

    2016-01-01

    This study focuses on the degree, nature and consequences of bullying or inappropriate behaviour among faculty personnel (n = 303) in a Finnish university. A total of 114 (38%) faculty members answered the email questionnaire. According to the results, 15% of the respondents had experienced bullying; in addition, 45% had experienced inappropriate…

  19. The entropic basis of collective behaviour

    PubMed Central

    Mann, Richard P.; Garnett, Roman

    2015-01-01

    We identify a unique viewpoint on the collective behaviour of intelligent agents. We first develop a highly general abstract model for the possible future lives these agents may encounter as a result of their decisions. In the context of these possibilities, we show that the causal entropic principle, whereby agents follow behavioural rules that maximize their entropy over all paths through the future, predicts many of the observed features of social interactions among both human and animal groups. Our results indicate that agents are often able to maximize their future path entropy by remaining cohesive as a group and that this cohesion leads to collectively intelligent outcomes that depend strongly on the distribution of the number of possible future paths. We derive social interaction rules that are consistent with maximum entropy group behaviour for both discrete and continuous decision spaces. Our analysis further predicts that social interactions are likely to be fundamentally based on Weber's law of response to proportional stimuli, supporting many studies that find a neurological basis for this stimulus–response mechanism and providing a novel basis for the common assumption of linearly additive ‘social forces’ in simulation studies of collective behaviour. PMID:25833243

  20. Dynamic behaviour of HPFRCC in tension

    NASA Astrophysics Data System (ADS)

    Cadoni, E.; Caverzani, A.; di Priscoi, M.

    2012-08-01

    High Performance Fiber Reinforced Cementitious Composites belong to a new class of structural materials characterized by high strength and ductility. Thanks to the high energy absorbed during the fracture process, due to multiple cracking and pull-out phenomena, they are often suggested for dynamic loading applications. Current understanding of the dynamic response is very limited because of very few investigations have been actually carried out. An experimental research aimed at contributing to the understanding of the behaviour of advanced fiber-reinforced cementitious composites subjected to low and high strain rates was carried out. The material investigated is a High Performance Fiber Reinforced Cementitious Composites. Straight high carbon steel micro-fibers were used. The material behaviour was investigated at several strain rates and the tests results were compared with their static behaviour. Tests at intermediate strain rates were carried out by means of a hydro-pneumatic machine (HPM), while high strain rates were investigated by exploiting a Split Hopkinson Tensile Bar (SHTB). A comparison between static and dynamic tests highlighted several relevant aspects regarding the influence of fibers on the peak strength and post-peak behaviour at high strain rates. Finally, this material will be employed in the construction of an innovative tunnel segment designed for extreme conditions (high temperature and shock).