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Sample records for chemo-mechanical coupling behaviour

  1. Analytical solution for one-dimensional chemo-mechanical coupling behavior of intelligent polymer gel

    NASA Astrophysics Data System (ADS)

    Yang, Qingsheng; Tian, Hui

    2011-11-01

    As an intelligent material, polymer gel is able to respond to external stimulus, including temperature, chemical concentration, pH, etc. The theoretical framework of chemo-mechanical coupling behavior for intelligent polymer gel is emphasized in this paper. Analytical solutions of the displacement and concentration function are found for one dimensional chemo-mechanical coupling problem. It is shown that the present chemo-mechanical theory can be applied to model chemo-mechanical coupling behavior of intelligent polymer gel. This study has important significance to reveal the mechanism of chemo-mechanical coupling behavior of the polymer gel.

  2. Analytical solution for one-dimensional chemo-mechanical coupling behavior of intelligent polymer gel

    NASA Astrophysics Data System (ADS)

    Yang, Qingsheng; Tian, Hui

    2012-04-01

    As an intelligent material, polymer gel is able to respond to external stimulus, including temperature, chemical concentration, pH, etc. The theoretical framework of chemo-mechanical coupling behavior for intelligent polymer gel is emphasized in this paper. Analytical solutions of the displacement and concentration function are found for one dimensional chemo-mechanical coupling problem. It is shown that the present chemo-mechanical theory can be applied to model chemo-mechanical coupling behavior of intelligent polymer gel. This study has important significance to reveal the mechanism of chemo-mechanical coupling behavior of the polymer gel.

  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

    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. 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

  11. 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

  12. Experimental investigations for the modeling of chemo-mechanical processes of anhydritic rock

    NASA Astrophysics Data System (ADS)

    Huber, Tara; Pimentel, Erich; Anagnostou, Georg

    2015-04-01

    When anhydritic rock comes into contact with water, the anhydrite dissolves and gypsum precipitates as a result of an oversaturation of the sulphate and calcium ions in the water. This anhydrite to gypsum transformation (AGT) leads to an increase in the solid volume by roughly 61% and possibly also of the pore volume, thus resulting in macroscopic swelling. In tunneling, swelling rock can cause massive damage, since it can exhibit high pressures on the lining or result in large deformations of the lining. Even though this phenomenon has already been observed more than a century ago, AGT in sulphatic rock still raises many open questions. One question we focus on is the mechanical (i.e. stress, strain) behavior of anhydritic rock during swelling. The coupled chemo-mechanical processes, i.e. the development of stresses and strains during AGT, has not been fully understood so far. A chemo-mechanical model must be considered which take anhydrite dissolution, gypsum precipitation as well as stresses and strains into account. In this contribution we present some fundamental research which was done in order to establish a relationship between AGT and the resulting or applied strains and stresses. The research contains experiments on samples consisting of anhydrite and kaolin under oedometric conditions. In order to reduce uncertainties due to swelling of clay as well as inhomogeneous compositions and structures of the natural rock samples, the experiments at the present stage of this research are performed on artificially created, reproducible samples. The samples contain 40% industrial anhydritic powder and 60% Polwhite E Chinaclay (of which the main component is kaolinite). The powders are mixed and compacted in a steel ring under high axial pressure, thus creating intact discs with a dry density of roughly 1.9 g/cm3. In a first series of Oedometer tests the swelling strain under various constant axial stress is measured until the maximal strain is reached. At the

  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. PMID:25656863

  14. 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.

  15. Bursting behaviour in coupled Josephson junctions

    NASA Astrophysics Data System (ADS)

    Hongray, Thotreithem; Balakrishnan, J.; Dana, Syamal K.

    2015-12-01

    We report an interesting bow-tie shaped bursting behaviour in a certain parameter regime of two resistive-capacitative shunted Josephson junctions, one in the oscillatory and the other in the excitable mode and coupled together resistively. The burst emerges in both the junctions and they show near-complete synchronization for strong enough couplings. We discuss a possible bifurcation scenario to explain the origin of the burst. An exhaustive study on the parameter space of the system is performed, demarcating the regions of bursting from other solutions.

  16. Bursting behaviour in coupled Josephson junctions.

    PubMed

    Hongray, Thotreithem; Balakrishnan, J; Dana, Syamal K

    2015-12-01

    We report an interesting bow-tie shaped bursting behaviour in a certain parameter regime of two resistive-capacitative shunted Josephson junctions, one in the oscillatory and the other in the excitable mode and coupled together resistively. The burst emerges in both the junctions and they show near-complete synchronization for strong enough couplings. We discuss a possible bifurcation scenario to explain the origin of the burst. An exhaustive study on the parameter space of the system is performed, demarcating the regions of bursting from other solutions. PMID:26723143

  17. 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

  18. 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

  19. 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

  20. Simulating uterine contraction by using an electro-chemo-mechanical model.

    PubMed

    Sharifimajd, Babak; Thore, Carl-Johan; Stålhand, Jonas

    2016-06-01

    Contractions of uterine smooth muscle cells consist of a chain of physiological processes. These contractions provide the required force to expel the fetus from the uterus. The inclusion of these physiological processes is, therefore, imperative when studying uterine contractions. In this study, an electro-chemo-mechanical model to replicate the excitation, activation, and contraction of uterine smooth muscle cells is developed. The presented modeling strategy enables efficient integration of knowledge about physiological processes at the cellular level to the organ level. The model is implemented in a three-dimensional finite element setting to simulate uterus contraction during labor in response to electrical discharges generated by pacemaker cells and propagated within the myometrium via gap junctions. Important clinical factors, such as uterine electrical activity and intrauterine pressure, are predicted using this simulation. The predictions are in agreement with clinically measured data reported in the literature. A parameter study is also carried out to investigate the impact of physiologically related parameters on the uterine contractility. PMID:26162461

  1. 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.

  2. Chemo-mechanical pushing of proteins along single-stranded DNA.

    PubMed

    Sokoloski, Joshua E; Kozlov, Alexander G; Galletto, Roberto; Lohman, Timothy M

    2016-05-31

    Single-stranded (ss)DNA binding (SSB) proteins bind with high affinity to ssDNA generated during DNA replication, recombination, and repair; however, these SSBs must eventually be displaced from or reorganized along the ssDNA. One potential mechanism for reorganization is for an ssDNA translocase (ATP-dependent motor) to push the SSB along ssDNA. Here we use single molecule total internal reflection fluorescence microscopy to detect such pushing events. When Cy5-labeled Escherichia coli (Ec) SSB is bound to surface-immobilized 3'-Cy3-labeled ssDNA, a fluctuating FRET signal is observed, consistent with random diffusion of SSB along the ssDNA. Addition of Saccharomyces cerevisiae Pif1, a 5' to 3' ssDNA translocase, results in the appearance of isolated, irregularly spaced saw-tooth FRET spikes only in the presence of ATP. These FRET spikes result from translocase-induced directional (5' to 3') pushing of the SSB toward the 3' ssDNA end, followed by displacement of the SSB from the DNA end. Similar ATP-dependent pushing events, but in the opposite (3' to 5') direction, are observed with EcRep and EcUvrD (both 3' to 5' ssDNA translocases). Simulations indicate that these events reflect active pushing by the translocase. The ability of translocases to chemo-mechanically push heterologous SSB proteins along ssDNA provides a potential mechanism for reorganization and clearance of tightly bound SSBs from ssDNA. PMID:27185951

  3. SEXUAL BEHAVIOUR AND DYSFUNCTION IN DIVORCE SEEKING COUPLES

    PubMed Central

    Gautam, Shiv; Batra, Lalit

    1996-01-01

    50 divorce seeking couples, when compared with 30 well adjusted couples, showed that sex-related factors and sexual dysfunctions were related to divorce seeking behaviour. A significantly high number of couples in the study group, reported a bad honeymoon, unsatisfactory coital experience, lack of cooperation from the spouse and variant sexual habits. The findings emphasis the importance of imparting adequate knowledge about sex and management of sexual dysfunctions, as part of marital therapy. PMID:21584156

  4. 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. PMID:23095058

  5. 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.

  6. Allosteric ring assembly and chemo-mechanical melting by the interaction between 5'-phosphate and λ exonuclease.

    PubMed

    Yoo, Jungmin; Lee, Gwangrog

    2015-12-15

    Phosphates along the DNA function as chemical energy frequently used by nucleases to drive their enzymatic reactions. Exonuclease functions as a machine that converts chemical energy of the phosphodiester-chain into mechanical work. However, the roles of phosphates during exonuclease activities are unknown. We employed λ exonuclease as a model system and investigated the roles of phosphates during degradation via single-molecule fluorescence resonance energy transfer (FRET). We found that 5' phosphates, generated at each cleavage step of the reaction, chemo-mechanically facilitate the subsequent post-cleavage melting of the terminal base pairs. Degradation of DNA with a nick requires backtracking and thermal fraying at the cleavage site for re-initiation via the formation of a catalytically active complex. Unexpectedly, we discovered that a phosphate of a 5' recessed DNA acts as a hotspot for an allosteric trimeric-ring assembly without passing through the central channel. Our study provides new insight into the versatile roles of phosphates during the processive enzymatic reaction. PMID:26527731

  7. 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

  8. Allosteric ring assembly and chemo-mechanical melting by the interaction between 5′-phosphate and λ exonuclease

    PubMed Central

    Yoo, Jungmin; Lee, Gwangrog

    2015-01-01

    Phosphates along the DNA function as chemical energy frequently used by nucleases to drive their enzymatic reactions. Exonuclease functions as a machine that converts chemical energy of the phosphodiester-chain into mechanical work. However, the roles of phosphates during exonuclease activities are unknown. We employed λ exonuclease as a model system and investigated the roles of phosphates during degradation via single-molecule fluorescence resonance energy transfer (FRET). We found that 5′ phosphates, generated at each cleavage step of the reaction, chemo-mechanically facilitate the subsequent post-cleavage melting of the terminal base pairs. Degradation of DNA with a nick requires backtracking and thermal fraying at the cleavage site for re-initiation via the formation of a catalytically active complex. Unexpectedly, we discovered that a phosphate of a 5′ recessed DNA acts as a hotspot for an allosteric trimeric-ring assembly without passing through the central channel. Our study provides new insight into the versatile roles of phosphates during the processive enzymatic reaction. PMID:26527731

  9. 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. PMID:9330720

  10. Caries-removal effectiveness of a papain-based chemo-mechanical agent: A quantitative micro-CT study.

    PubMed

    Neves, Aline A; Lourenço, Roseane A; Alves, Haimon D; Lopes, Ricardo T; Primo, Laura G

    2015-01-01

    The aim of this study was to access the effectiveness and specificity of a papain-based chemo-mechanical caries-removal agent in providing minimum residual caries after cavity preparation. In order to do it, extracted carious molars were selected and scanned in a micro-CT before and after caries-removal procedures with the papain-based gel. Similar parameters for acquisition and reconstruction of the image stacks were used between the scans. After classification of the dentin substrate based on mineral density intervals and establishment of a carious tissue threshold, volumetric parameters related to effectiveness (mineral density of removed dentin volume and residual dentin tissue) and specificity (relation between carious dentin in removed volume and initial caries) of this caries-removal agent were obtained. In general, removed dentin volume was similar or higher than the initial carious volume, indicating that the method was able to effectively remove dentin tissue. Samples with an almost perfect accuracy in carious dentin removal also showed an increased removal of caries-affected tissue. On the contrary, less or no affected dentin was removed in samples where some carious tissue was left in residual dentin. Mineral density values in residual dentin were always higher or similar to the threshold for mineral density values in carious dentin. In conclusion, the papain-based gel was effective in removing carious dentin up to a conservative in vitro threshold. Lesion characteristics, such as activity and morphology of enamel lesion, may also influence caries-removal properties of the method. PMID:25809787

  11. Coupling behaviour of tapered highly multimodal dielectric waveguides as part of PCB-level optical interconnects

    NASA Astrophysics Data System (ADS)

    Soenmez, Yasin; Mrozynski, Gerd; Schrage, Juergen

    2010-05-01

    Optical interconnects replace electrical links increasingly at shorter distances. At printed circuit board (PCB) level highly multimodal polymer channel waveguides are the chosen approach to meet bandwidth-length and bandwidth-density requirements. One important challenge of board integrated waveguides is the coupling problem. The manufacturing process of PCBs leads to relatively high placement tolerances which cause poor optical coupling efficiency due to mechanical misalignment between separate components, e.g.: 1) Coupling between a VCSEL and the board integrated waveguides; 2) Coupling between waveguides in two separate boards. This paper deals with the deployment of tapered dielectric multimode waveguides for increasing the optical coupling robustness towards mechanical misalignments in these two coupling applications. A coupled mode approach for calculation of the mode coupling and power loss in a taper with decreasing width has been presented before [5]. In [6], the two above mentioned coupling applications for tapered dielectric waveguides have been dealt with, but only the coupling efficiency in case of longitudinal misalignment has been calculated. In this paper, results of advanced analysis of the two applications are presented. The coupling efficiency in case of transverse misalignment is simulated by a ray-optical approach. Furthermore the results of measurements of the coupling behaviour of board integrated tapered waveguides are presented. The results show that tapered multimodal dielectric waveguides have the capability to increase the coupling efficiency significantly if some conditions are fulfilled.

  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. PMID:26195263

  13. 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.

  14. Sensitivity comparison of vapor trace detection of explosives based on chemo-mechanical sensing with optical detection and capacitive sensing with electronic detection.

    PubMed

    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

  15. 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

  16. 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

  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. 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.

  19. 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. PMID:24814417

  20. 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

  1. Scattering in one dimension: The coupled Schrödinger equation, threshold behaviour and Levinson's theorem

    NASA Astrophysics Data System (ADS)

    Kiers, K. A.; van Dijk, W.

    1996-12-01

    We formulate scattering in one dimension due to the coupled Schrödinger equation in terms of the S matrix, the unitarity of which leads to constraints on the scattering amplitudes. Levinson's theorem is seen to have the form η(0)=π(nb+1/2n-1/2N), where η(0) is the phase of the S matrix at zero energy, nb the number of bound states with nonzero binding energy, n the number of half-bound states, and N the number of coupled equations. In view of the effects due to the half-bound states, the threshold behaviour of the scattering amplitudes is investigated in general, and is also illustrated by means of particular potential models.

  2. 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.

  3. 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

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

    NASA Astrophysics Data System (ADS)

    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

  5. 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

  6. 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

  7. 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

  8. Self-organized criticality, plasticity and sensorimotor coupling. Explorations with a neurorobotic model in a behavioural preference task.

    PubMed

    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

  9. 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

  10. 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.

  11. How do couples influence each other’s physical activity behaviours in retirement? An exploratory qualitative study

    PubMed Central

    2013-01-01

    Background Physical activity patterns have been shown to change significantly across the transition to retirement. As most older adults approach retirement as part of a couple, a better understanding of how spousal pairs influence each other’s physical activity behaviour in retirement may help inform more effective interventions to promote physical activity in older age. This qualitative study aimed to explore and describe how couples influence each other’s physical activity behaviour in retirement. Methods A qualitative descriptive study that used purposive sampling to recruit seven spousal pairs with at least one partner of each pair recruited from the existing EPIC-Norfolk study cohort in the east of England, aged between 63 and 70 years and recently retired (within 2-6 years). Semi-structured interviews with couples were performed, audio-recorded, transcribed verbatim and analysed using data-driven content analysis. Results Three themes emerged: spousal attitude towards physical activity, spouses’ physical activity behaviour and spousal support. While spouses’ attitudes towards an active retirement were concordant, attitudes towards regular exercise diverged, were acquired across the life course and were not altered in the transition to retirement. Shared participation in physical activity was rare and regular exercise was largely an individual and independent habit. Spousal support was perceived as important for initiation and maintenance of regular exercise. Conclusions Interventions should aim to create supportive spousal environments for physical activity in which spouses encourage each other to pursue their preferred forms of physical activity; should address gender-specific needs and preferences, such as chances for socialising and relaxation for women and opportunities for personal challenges for men; and rather than solely focusing on promoting structured exercise, should also encourage everyday physical activity such as walking for transport

  12. 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.

  13. 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

  14. Experimental and Mathematical Evaluation of Dynamic Behaviour of AN Oil-Air Coupling Shock Absorber

    NASA Astrophysics Data System (ADS)

    PING, Y.

    2003-11-01

    The physical mechanism of the actual shock absorber with multi-types of damping and non-linear stiffness through coupling the oil, air, rubber and spring by ingenious devices is systematically investigated. The experimental results of the key-model machine in multi-parameter coupling dynamic test show complex non-linearity dynamic characteristics. Based on this, the non-linear dynamic model for the shock absorber is presented by analysing the internal fluid dynamic phenomenon with respect to the shock absorber. Comparisons with experimental data confirm the validity of the model. Using the model, it is possible to evaluate the importance of different factors for designing the shock absorber.

  15. Modelling of the evaporation behaviour of particulate material for slurry nebulization inductively coupled plasma atomic emission spectrometry

    NASA Astrophysics Data System (ADS)

    Merten, D.; Heitland, P.; Broekaert, J. A. C.

    1997-11-01

    This paper is an electronic publication in Spectrochimica Acta Electronica (SAE), the electronic section of Spectrochimica Acta, Part B (SAB). This hardcopy text, comprising the main body and an appendix, is accompanied by a disk with programs, data files and a brief manual. The main body discusses purpose, design principle and usage of the computer software for modelling the evaporation behaviour of particles in inductively coupled plasma atomic emission spectrometry (ICP-AES). Computer software has been developed in FORTRAN 77 language in order to simulate the evaporation behaviour of particles of refractory materials such as encountered in the analysis of advanced ceramic powders by slurry nebulization inductively coupled argon plasma atomic spectrometry. The program simulates the evaporation of single particles in the inductively coupled plasma and also enable it to calculate on the base of a given particle size distribution the evaporation behaviour of all the particles contained in a sample. In a so-called "intensity concept", the intensity is calculated as a function of the observation height in order to determine recovery rates for slurries compared with aqueous solutions. This yields a quick insight whether a calibration with aqueous solutions can be used for analysis of slurries of a given powder by slurry nebulization ICP-AES and also is a help in determining the optimal parameters for analyses of powders by means of slurry nebulization ICP-AES. Applications for the evaporation of Al 2O 3 and SiC powders document the usefulness of the model for the case of a 1.5 kW argon ICP of which the temperature at 8 mm above the load coil has been determined to be 6100 K. The model predicts the maximum particle size for SiC and Al 2O 3 that can be transported (10-15 μm) and evaporated for a given efficiency under given experimental conditions. For both Al 2O 3 and SiC, two ceramic powders of different grain size were investigated. The median particle sizes cover

  16. 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.

  17. 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

  18. 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

  19. COUPLING

    DOEpatents

    Hawke, B.C.

    1963-02-26

    This patent relates to a releasable coupling connecting a control rod to a control rod drive. This remotely operable coupling mechanism can connect two elements which are laterally and angviarly misaligned, and provides a means for sensing the locked condition of the elements. The coupling utilizes a spherical bayonet joint which is locked against rotation by a ball detent lock. (AEC)

  20. 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)

  1. 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

  2. Using Haines Index coupled with fire weather model predicted from high resolution LAM forecasts to asses wildfire extreme behaviour in Southern Europe.

    NASA Astrophysics Data System (ADS)

    Gaetani, Francesco; Baptiste Filippi, Jean; Simeoni, Albert; D'Andrea, Mirko

    2010-05-01

    Haines Index (HI) was developed by USDA Forest Service to measure the atmosphere's contribution to the growth potential of a wildfire. The Haines Index combines two atmospheric factors that are known to have an effect on wildfires: Stability and Dryness. As operational tools, HI proved its ability to predict plume dominated high intensity wildfires. However, since HI does not take into account the fuel continuity, composition and moisture conditions and the effects of wind and topography on fire behaviour, its use as forecasting tool should be carefully considered. In this work we propose the use of HI, predicted from HR Limited Area Model forecasts, coupled with a Fire Weather model (i.e., RISICO system) fully operational in Italy since 2003. RISICO is based on dynamic models able to represent in space and in time the effects that environment and vegetal physiology have on fuels and, in turn, on the potential behaviour of wildfires. The system automatically acquires from remote databases a thorough data-set of input information both of in situ and spatial nature. Meteorological observations, radar data, Limited Area Model weather forecasts, EO data, and fuel data are managed by a Unified Interface able to process a wide set of different data. Specific semi-physical models are used in the system to simulate the dynamics of the fuels (load and moisture contents of dead and live fuel) and the potential fire behaviour (rate of spread and linear intensity). A preliminary validation of this approach will be provided with reference to Sardinia and Corsica Islands, two major islands of the Mediterranean See frequently affected by extreme plume dominated wildfires. A time series of about 3000 wildfires burnt in Sardinia and Corsica in 2007 and 2008 will be used to evaluate the capability of HI coupled with the outputs of the Fire Weather model to forecast the actual risk in time and in space.

  3. Reproductive behaviour of couples at risk for sickle cell disease in Cuba: a follow-up study.

    PubMed

    Dorticós-Balea, A; Martin-Ruiz, M; Hechevarria-Fernández, P; Robaina-Castellanos, M S; Rodriguez-Blanco, M; Moras-Bracero, F; Granda Ibarra, H

    1997-08-01

    Three hundred and forty-three Cuban women at risk of having children with sickle cell anaemia or sickle cell-haemoglobin C disease were interviewed 2-8 years after the index pregnancy (that in which their risk was detected). The aim was to collect information on their attitude towards prenatal diagnosis in subsequent pregnancies. Twenty-two per cent (75/343) had dissolved their marriage and 9 per cent of these (7/75) considered that their at-risk status had influenced the separation. Sixty-three per cent of stable couples at risk (168/268) had decided to have no further children; 27 per cent of these (45/168) were afraid of having an affected child and 4 per cent (7/168) were afraid of the obstetric procedure. Nineteen per cent of the stable couples at risk (52/268) had had at least one further child or pregnancy. Of these, 44 per cent (23/52) requested prenatal diagnosis early and spontaneously, and a further 44 per cent (23/52) requested prenatal diagnosis but after re-identification by screening and recounselling. Only 12 per cent (6/52) did not request prenatal diagnosis. Attitude towards prenatal diagnosis was most positive among more educated women. The general perception of the prevention programme was good. PMID:9267897

  4. Examination of evaporative fraction diurnal behaviour using a soil-vegetation model coupled with a mixed-layer model

    NASA Astrophysics Data System (ADS)

    Lhomme, J.-P.; Elguero, E.

    In many experimental conditions, the evaporative fraction, defined as the ratio between evaporation and available energy, has been found stable during daylight hours. This constancy is investigated over fully covering vegetation by means of a land surface scheme coupled with a mixed-layer model, which accounts for entrainment of overlying air. The evaporation rate follows the Penman-Monteith equation and the surface resistance is given by a Jarvis type parameterization involving solar radiation, saturation deficit and leaf water potential. The diurnal course of the evaporative fraction is examined, together with the influence of environmental factors (soil water availability, solar radiation input, wind velocity, saturation deficit above the well-mixed layer). In conditions of fair weather, the curves representing the diurnal course of the evaporative fraction have a typical concave-up shape. Around midday (solar time) these curves appear as relatively constant, but always lower that the daytime mean value. Evaporative fraction decreases when soil water decreases or when solar energy increases. An increment of saturation deficit above the mixed-layer provokes only a slight increase of evaporative fraction, and wind velocity has almost no effect. The possibility of estimation daytime evaporation from daytime available energy multiplied by the evaporative fraction at a single time of the day is also investigated. It appears that it is possible to obtain fairly good estimates of daytime evaporation by choosing adequately the time of the measurement of the evaporative fraction. The central hours of the day, and preferably about 3 hr before or after noon, are the most appropriate to provide good estimates. The estimation appears also to be much better when soil water availability (or evaporation) is high than when it is low.

  5. 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

  6. 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.

  7. 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.

  8. 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”.

  9. 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

  10. Tamoxifen derivatives for delivery of the antitumoral (DACH)Pt group: selective synthesis by McMurry coupling, and biochemical behaviour.

    PubMed

    Top, Siden; Kaloun, El Bachir; Vessières, Anne; Leclercq, Guy; Laïos, Ioanna; Ourevitch, Michèle; Deuschel, Christine; McGlinchey, Michael J; Jaouen, Gérard

    2003-08-01

    The goal of our study was to potentiate the effects of the ((R,R)-trans-1,2-diaminocyclohexane)-platinum(II) fragment [(DACH)Pt], known for its cytotoxic properties, either with tamoxifen (Tam), the most widely used antiestrogen in the treatment of hormone-dependent breast cancers, or with its active metabolite hydroxytamoxifen (hydroxy-Tam). We coupled Tam or hydroxy-Tam derivatives bearing a malonato group at the para position of the beta aromatic ring with the (DACH)Pt fragment. The malonato-Tam and malonato-hydroxy-Tam compounds were prepared through McMurry coupling of the appropriate ketones. The presence of the malonate group resulted in a pronounced stereospecificity in the reaction, since malonato-Tam was obtained only as the Z isomer, while malonato-hydroxy-Tam was obtained as an 80/20 E/Z mixture. Attribution of the isomeric structures was achieved by 2D NMR spectroscopy. The platinum complexes (DACH)Pt-malonato-Tam and (DACH)Pt-malonato-hydroxy-Tam were then prepared by coupling the barium salts derived from the malonato-Tam and malonato-hydroxy-Tam with the nitrate derived from (DACH)PtCl(2). Study of the biochemical properties of these two platinum complexes showed that, while the hydroxy-Tam complex is satisfactorily recognized by the estrogen receptor (relative binding affinity, RBA=6.4 %), the Tam complex is less well recognized (RBA=0.5 %). The effects of these complexes on two hormone-dependent breast cancer cell lines (MCF7 and MVLN) were studied in vitro. Both complexes showed an antiproliferative effect on MCF7 cells, and an antiestrogenic effect on MVLN cells. The observed effects appear to be essentially antihormonal, since incorporation of the (DACH)Pt fragment into the tamoxifen skeleton did not cause an increase in the cytotoxicity of the complexes. PMID:12898627

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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

  16. 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.

  17. Behaviour Recovery. Second Edition

    ERIC Educational Resources Information Center

    Rogers, Bill

    2004-01-01

    This second edition of Behaviour Recovery puts emphasis on teaching behaviour concerning children with emotional and behavioural disorders (EBD). These children have many factors in their lives that affect their behaviour over which schools have limited control. This book acknowledges the challenge and explores the practical realities, options and…

  18. 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. PMID:26416122

  19. 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.

  20. Oxygen reduction reaction induced pH-responsive chemo-mechanical hydrogel actuators.

    PubMed

    Yu, Cunjiang; Yuan, Peixi; Erickson, Evan M; Daly, Christopher M; Rogers, John A; Nuzzo, Ralph G

    2015-10-28

    We describe and characterize elementary designs for electrochemical micro- and macro-scale chemomechanical hydrogel actuators. The actuation of a pH-sensitive cross-linked polyacrylic acid (PAA) hydrogel is driven in the model devices through the oxygen reduction reaction (ORR) occurring at the electrodes of an embedded Au mesh micro-electrochemical array. Proton consumption by the ORR at the cathode of the embedded electrochemical cell leads to the formation of a localized pH gradient that in turn drives the strain response in the composite actuators. The dynamics result from the ionization of the carboxylic acid moieties of the PAA network in the high pH region, yielding an osmotic pressure that drives a volumetric expansion due to water imbibition. This system actuates both stably and reversibly; when the electrochemically-induced ORR is halted, the localized pH gradient dissipates due to diffusive mixing, which in turn relaxes the induced strains. Two approaches to the fabrication of hydrogel actuators were examined in this work. The first method adopted a design based on small flagella (∼0.2 mm × 1.5 mm × 60 μm, width × length × height) in which the actuating PAA structures are molded atop a set of fixed electrodes mounted on a supporting substrate. These hydrogel actuators show fast, large-amplitude, and largely reversible responses in the ORR mediated chemomechanical dynamics. We also investigated larger hydrogel actuators (∼4.5 mm × 11 mm × 1 mm, width × length × height), based on an autonomous design that embeds an open mesh stretchable micro-electrode array within the hydrogel. The significant and design-dependent impacts of mass transfer on the chemomechanical dynamics are evidenced in each case, a feature examined to elucidate more efficient mesoscopic design rules for actuators of this form. PMID:26323563

  1. Utilizing Chemo-mechanically Functionalized Oscillating Fins to ``Catch and Release'' Nanoparticles in Binary Flow

    NASA Astrophysics Data System (ADS)

    Liu, Ya; Kuksenok, Olga; Bhattacharya, Amitabh; Ma, Yongting; He, Ximin; Aizenberg4, Joanna; Balazs, Anna

    2014-03-01

    In biomimetics, designing an effective ``catch and release'' device for the selective removal of target species from the surrounding solution is critical for developing autonomous sensors and sorters. Using computer simulations, we model an array of oscillating fins that are tethered on the floor of a microchannel and immersed in a mixture of binary fluid stream and binary nanoparticles. During the oscillation, the fins with the specific chemical wetting reach the upper fluid when they are upright and are entirely immersed within the lower stream when they are tilted. We introduce specific interaction between the fins and particulates in the solution and determine conditions where the oscillating fins can selectively ?catch? target nanoparticles within the upper fluid stream and then release these particles into the lower stream. We isolate the effects of wetting contact angle between fins and fluid and the mode of fins' oscillations that lead to the efficient extraction of target species from the upper stream and their placement into the lower fluid. These studies provide fundamental insights into the system's complex dynamics and mechanism for detection, separation, and purification of multi-component mixtures.

  2. Utilizing chemo-mechanically functionalized oscillating fins to ``catch and release'' nanoparticles in binary flow

    NASA Astrophysics Data System (ADS)

    Liu, Ya; Ma, Yongting; Bhattacharya, Amitabh; Kuksenok, Olga; He, Ximin; Aizenberg, Joanna; Balazs, Anna

    2013-11-01

    In biomimetics, designing an effective ``catch and release'' device for the selective removal of target species from the surrounding solution is critical for developing autonomous sensors and sorters. Using computational simulation, we model an array of oscillating fins that are tethered on the floor of a microchannel and immersed in a binary-fluid stream. During the oscillation, the fins with the specific chemical wetting reach the upper fluid when they are upright and are entirely within the lower stream when they are tilted. We introduce specific adhesive interactions between the fins and particulates in the solution and determine conditions where the oscillating fins can selectively bind (``catch'') target nanoparticles within the upper fluid stream and then release these particles into the lower stream. We isolate the effects of chemical wetting on the fins (e.g., wetting contact angle between fins and fluid) and mechanical parameters (e.g., frequency of fins' oscillations) that lead to the efficient extraction of target species from the upper stream and placement into the lower fluid. Our understanding provides fundamental insights into the system's complex dynamics and mechanism for detection, separation, and purification of multi-component mixtures.

  3. 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.

  4. Coupled Mechanical and Electrochemical Phenomena in Lithium-Ion Batteries

    NASA Astrophysics Data System (ADS)

    Cannarella, John

    Lithium-ion batteries are complee electro-chemo-mechanical systems owing to a number of coupled mechanical and electrochemical phenomena that occur during operation. In this thesis we explore these phenomena in the context of battery degradation, monitoring/diagnostics, and their application to novel energy systems. We begin by establishing the importance of bulk stress in lithium-ion batteries through the presentation of a two-year exploratory aging study which shows that bulk mechanical stress can significantly accelerate capacity fade. We then investigate the origins of this coupling between stress and performance by investigating the effects of stress in idealized systems. Mechanical stress is found to increase internal battery resistance through separator deformation, which we model by considering how deformation affects certain transport properties. When this deformation occurs in a spatially heterogeneous manner, local hot spots form, which accelerate aging and in some cases lead to local lithium plating. Because of the importance of separator deformation with respect to mechanically-coupled aging, we characterize the mechanical properties of battery separators in detail. We also demonstrate that the stress state of a lithium-ion battery cell can be used to measure the cell's state of health (SOH) and state of charge (SOC)--important operating parameters that are traditionally difficult to measure outside of a laboratory setting. The SOH is shown to be related to irreversible expansion that occurs with degradation and the SOC to the reversible strains characteristic of the cell's electrode materials. The expansion characteristics and mechanical properties of the constituent cell materials are characterized, and a phenomenological model for the relationship between stress and SOH/SOC is developed. This work forms the basis for the development of on-board monitoring of SOH/SOC based on mechanical measurements. Finally we study the coupling between mechanical

  5. 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. PMID:25937344

  6. 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

  7. 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.

  8. Helix coupling

    DOEpatents

    Ginell, William 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.

  9. 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

  10. Behavioural therapy of suicidality.

    PubMed

    Schneider, Barbara

    2012-11-01

    Suicidal behaviour is a serious public health issue. Suicidal behaviour includes completed suicide, suicide attempts, suicidal intent and/or plans and suicide ideation. Two prominent mechanisms, behavioural deficits, in particular poor problem-solving skills, and a certain cognitive style with overgeneralization, distortion and lack of positive expectations, have been identified in suicidal patients so far. Besides general therapy strategies, including the diagnostic process and a collaborative, confident relationship and strengthening of protective factors, specific behavioural strategies should aim at the modification of the behavioural repertoire and of cognitive strategies. The modification of the behavioural repertoire includes the direct modification of the behaviour, acquiring techniques for stress reduction and learning problem-solving strategies. Applied cognitive techniques comprise such as thought-stopping, examining options and alternatives, fantasizing consequences, externalizing inner voices, and reattribution. Psychotherapy with suicidal patients has a specific feature: It requires high activity of the therapist in terms of motivation and guidance of the patient. Regular assessment of the suicide risk at every session is a must. Nevertheless, the therapist should always be aware that it is impossible to prevent all suicidal acts. PMID:22926057

  11. Sedentary behaviour in youth.

    PubMed

    Pate, Russell R; Mitchell, Jonathan A; Byun, Wonwoo; Dowda, Marsha

    2011-09-01

    The purpose of this review is to describe the amount of time children spend in sedentary behaviour and to determine if there are specific factors that associate with sedentary behaviour in children. The following search terms were used to identify relevant articles: sedentary behaviour, inactivity, television, computer, video games, small screen, sitting, prevalence, patterns, correlates, factors and determinants. The databases used to conduct the search included PubMed, PsycINFO, ERIC (Education Resources Information Center) and Academic Search Premier. The studies reviewed were limited to those that sampled children (2-18 years), were written in English and used a measure of sedentary behaviour as the dependent variable. Several studies reported the time spent watching television or the proportion of children at or above a threshold for television viewing (eg, ≥3 h/day). Among the accelerometer studies included, the National Health and Nutrition Examination Survey is the largest and reported ∼6.1, 7.5 and 8.0 h/day mean sedentary time in children 6-11, 12-15 and 16-19 years old, respectively. Taken together, the existing literature across the world indicates a slightly higher level of sedentary behaviour in older children. Higher levels of sedentary behaviour were also reported in non-white children, children from lower socioeconomic status background and children from households with more access to televisions/computers. Lower levels of sedentary behaviour were reported in children whose parents have rules/limitations on screen time. PMID:21836174

  12. 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. PMID:26385066

  13. Cognitive science and behaviourism.

    PubMed

    Skinner, B F

    1985-08-01

    In this paper it is argued that cognitive scientists, claiming the support of brain science and computer simulation, have revived a traditional view that behaviour is initiated by an internal, autonomous mind. In doing so, they have misused the metaphor of storage and retrieval, given neurology a misleading assignment, frequently replaced controlled experimental conditions with mere descriptions of conditions and the assessment of behaviour with statements of expectations and intentions, given feelings and states of mind the status of causes of behaviour rather than the products of the causes, and failed to define many key terms in dimensions acceptable to science. PMID:4041702

  14. 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

  15. 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.

  16. Researching sexual and reproductive behaviour: a peer ethnographic approach.

    PubMed

    Price, Neil; Hawkins, Kirstan

    2002-10-01

    In recent years, ethnographic research has challenged the notion within demography that fertility-related behaviour is the outcome of individualistic calculations of the costs and benefits of having children. Anthropology has further criticised the abstraction in demographic analysis of sexual behaviour and fertility decision-making from the socio-cultural and political context in which the individual or couple is located. Within demography itself, institutional and political-economic analyses have argued strongly that sexual and reproductive behaviour must be understood within locally specific social, cultural, economic and political contexts. Positivist and empiricist research methods, such as the sample survey and focus groups, which continue to dominate demographic inquiry and applied research into sexual and reproductive behaviour, have been shown to be limited in their ability to inform about the process of behaviour change and contexts within which different behaviours occur. The article introduces a new methodology for researching sexual and reproductive behaviour, called the peer ethnographic approach, which the authors have developed in an attempt to address some of the limitations of the methods which currently dominate research into sexual and reproductive behaviour. The peer ethnographic methodology is discussed in detail and the results of recent field-testing are reported, which show that, although the approach has limitations, it also has the potential to make a significant contribution to our understanding of sexual and reproductive behaviour. PMID:12231012

  17. 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.

  18. Optical coupling

    NASA Astrophysics Data System (ADS)

    Bock, J. J.; Gundersen, J.; Lee, A. T.; Richards, P. L.; Wollack, E.

    2009-03-01

    This paper describes contributions to the CMBpol Technology Study Workshop concerning optical coupling structures. These are structures in or near the focal plane which convert the free space wave to a superconducting microstrip on a SI wafer, or to the waveguide input to a HEMT receiver. In addition to an introduction and conclusions by the editor, this paper includes independent contributions by Bock on 'Planar Antenna-Coupled Bolometers for CMB Polarimetry', by Gunderson and Wollack on 'Millimeter-Wave Platlet Feeds', and by Lee on 'Multi-band Dual-Polarization Lens-coupled Planar Antennas for Bolometric CMB polarimetry.'

  19. 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.

  20. 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

  1. 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

  2. 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

  3. 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. PMID:25586854

  4. 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.

  5. 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)

  6. Modelling cellular behaviour

    NASA Astrophysics Data System (ADS)

    Endy, Drew; Brent, Roger

    2001-01-01

    Representations of cellular processes that can be used to compute their future behaviour would be of general scientific and practical value. But past attempts to construct such representations have been disappointing. This is now changing. Increases in biological understanding combined with advances in computational methods and in computer power make it possible to foresee construction of useful and predictive simulations of cellular processes.

  7. Swaziland Behavioural Assessment Series.

    ERIC Educational Resources Information Center

    Ziyane, Masotsha J.; And Others

    The Swaziland Behavioural Assessment Series (SBAS) is a battery of ability tests derived from the Flanagan Aptitude Classification Tests and the Internationally Developed Tests, for use in the guidance of secondary school students towards relevant educational and vocational opportunities. The SBAS has been field tested in Swaziland. Sixteen…

  8. 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…

  9. 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.

  10. 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

  11. The couple as context: Latino gay male couples and HIV

    PubMed Central

    Beougher, Sean C.; Gómez, Walter; Hoff, Colleen C.

    2011-01-01

    HIV prevention efforts with gay men in relationships frequently omit primary partners. When they are considered, examinations of race/ethnicity are often overlooked despite higher infection rates among gay men of colour. Acknowledging both the need to contextualise the behaviours that may affect HIV risk for gay men of colour and the disproportionate impact of HIV on Latino gay men, the present study utilised semi-structured, qualitative interviews to explore relationship dynamics, sexual agreements and behaviours, and safer sex choices and HIV risk among nine Latino gay male couples. All participants were HIV-negative and in concordant negative relationships. Additionally, nearly all reported closed agreements. Analysis revealed participants engaging in four behaviours that may actively reduce their HIV risk: approaching sexual agreements from a practical standpoint, maintaining a high literacy around HIV, having exposure to social support groups for Latino gay men, and finding support in their relationship with another Latino gay man. Additional issues are raised where long-term HIV prevention is concerned. Intimate relationships are an important context for understanding both HIV risk and prevention among Latino gay men. Likewise, race/ethnicity provides an indispensable perspective on all research with gay couples. Future prevention efforts with gay men must strive to include both. PMID:21082463

  12. Composite Material Behaviour Under Shock Loading

    NASA Astrophysics Data System (ADS)

    Vignjevic, R.; Campbell, J. C.; Hazell, P.; Bourne, N. K.

    2007-06-01

    Composite materials have been of significant interest due to widespread application of anisotropic materials in aerospace and civil engineering problems. For example, composite materials are one of the important types of materials in the construction of modern aircraft due to their mechanical properties. The strain rate dependent mechanical behaviour of composite materials is important for applications involving impact and dynamic loading. Therefore, we are interested in understanding the composite material mechanical properties and behaviour for loading rates between quasistatic and 1x108s-1. This paper investigates modeling of shock wave propagation in orthotropic materials in general and a specific type of CFC composite material. The determination of the equation of state and its coupling with the rest of the constitutive model for these materials is presented and discussed along with validation from three dimensional impact tests.

  13. Infertility, infertility treatment and behavioural problems in the offspring.

    PubMed

    Zhu, Jin Liang; Obel, Carsten; Basso, Olga; Henriksen, Tine B; Bech, Bodil H; Hvidtjørn, Dorte; Olsen, Jørn

    2011-09-01

    Behavioural patterns in children of infertile couples may be influenced by both the underlying causes of infertility and stress in the couples. Treatment procedures, such as culture media and manipulation of gametes and embryos, may also result in developmental problems. We examined behavioural problems in children as a function of infertility and infertility treatment, using data from three population-based birth cohorts in Denmark (Aalborg-Odense Birth Cohort, Aarhus Birth Cohort and Danish National Birth Cohort). Information on time to pregnancy and infertility treatment was collected during pregnancy. Children aged between 7 and 21 years were assessed using the Strengths and Difficulties Questionnaire (SDQ). The SDQ was completed by mothers in all cohorts and, in addition, by teachers in the Aarhus cohort and by children themselves in the Aalborg-Odense cohort. Children born after a time to pregnancy of >12 months and no infertility treatment had a behavioural pattern similar to children of fertile parents. Teachers reported a higher total difficulties score for children born after infertility treatment, but no significant differences were seen on any subscales of the teachers' report, and neither the mothers nor the children reported any differences on the total difficulties score and the prosocial behaviour score. Our results are thus overall reassuring regarding behavioural problems in children born to infertile couples, regardless of infertility treatment. PMID:21819428

  14. Viability of nonminimally coupled f (R) gravity

    NASA Astrophysics Data System (ADS)

    Bertolami, Orfeu; Páramos, Jorge

    2016-03-01

    In this work we explore the viability of nonminimally coupled matter-curvature gravity theories, namely the conditions required for the absence of tachyon instabilities and ghost degrees of freedom. We contrast our finds with recent claims of a pathological behaviour of this class of models, which resorted to, in our view, an incorrect analogy with k-essence.

  15. 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

  16. 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

  17. 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.

  18. 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…

  19. Aminergic Control and Modulation of Honeybee Behaviour

    PubMed Central

    Scheiner, R; Baumann, A; Blenau, W

    2006-01-01

    Biogenic amines are important messenger substances in the central nervous system and in peripheral organs of vertebrates and of invertebrates. The honeybee, Apis mellifera, is excellently suited to uncover the functions of biogenic amines in behaviour, because it has an extensive behavioural repertoire, with a number of biogenic amine receptors characterised in this insect. In the honeybee, the biogenic amines dopamine, octopamine, serotonin and tyramine modulate neuronal functions in various ways. Dopamine and serotonin are present in high concentrations in the bee brain, whereas octopamine and tyramine are less abundant. Octopamine is a key molecule for the control of honeybee behaviour. It generally has an arousing effect and leads to higher sensitivity for sensory inputs, better learning performance and increased foraging behaviour. Tyramine has been suggested to act antagonistically to octopamine, but only few experimental data are available for this amine. Dopamine and serotonin often have antagonistic or inhibitory effects as compared to octopamine. Biogenic amines bind to membrane receptors that primarily belong to the large gene-family of GTP-binding (G) protein coupled receptors. Receptor activation leads to transient changes in concentrations of intracellular second messengers such as cAMP, IP3 and/or Ca2+. Although several biogenic amine receptors from the honeybee have been cloned and characterised more recently, many genes still remain to be identified. The availability of the completely sequenced genome of Apis mellifera will contribute substantially to closing this gap. In this review, we will discuss the present knowledge on how biogenic amines and their receptor-mediated cellular responses modulate different behaviours of honeybees including learning processes and division of labour. PMID:18654639

  20. Critical Wavelike Behaviour in Stringy Gravity with Yang Mills Source and Cosmological Constant

    SciTech Connect

    Slagter, Reinoud J.; Masselink, Derk

    2006-11-03

    We investigate numerically the behaviour of the self-gravitating coupled Einstein-Yang-Mills system on an axially symmetric five dimensional space time, with and without the Gauss-Bonnet term. We observe that the critical behaviour at the threshold of black hole formation is present in the 5-dimensional model and depends critically on the value of the cosmological constant and the Gauss-Bonnet coupling.

  1. 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

  2. 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. PMID:25462876

  3. The antifriction behaviours of ?

    NASA Astrophysics Data System (ADS)

    Yan, Feng-yuan; Xue, Qun-ji

    1997-03-01

    In this paper, the antifriction behaviours of 0022-3727/30/5/010/img2 (3:1) molecules and their crystal powder were evaluated by different methods. It was found that the 0022-3727/30/5/010/img2 crystal powder possessed hexagonal close packed (hcp) crystal structure with a = 10.1 Å and c = 16.55 Å, and a transformation of crystal structure from hcp to face centred cubic (fcc) occurred easily during friction (burnishing). It was confirmed that two kinds of process, breakage of 0022-3727/30/5/010/img2 powder coagulated by nanoscale single crystals and rearrangement of the molecules along the friction direction, had occurred under the friction force. The extreme pressure (EP) performance of 0022-3727/30/5/010/img2 as an additive in paraffin liquid was investigated on an SRV oscillating wear machine. It was found that the extreme pressure load (EP value) of paraffin liquid was increased by dispersion of 0022-3727/30/5/010/img2 powder, accompanied by a slight improvement in the antifriction behaviour. it was confirmed that the improvement in EP value and antifriction behaviour of oil was dependent on the crystal structure of 0022-3727/30/5/010/img2 powder, but independent of the spherical molecular structure of 0022-3727/30/5/010/img8 or 0022-3727/30/5/010/img9. The burnishing experimental results also proved that the antifriction behaviour was determined by the crystal structure and had no relation to the molecular structure. It was also found that fullerenes possessed some physical properties similar to those of graphite. Since the formation of compact fullerenes with high shear strength during friction can be effectively prevented by some other lubricants, it is suggested that fullerenes should be mixed with other lubricants for tribological application.

  4. Uncertainty Analysis of Model Coupling

    NASA Astrophysics Data System (ADS)

    Held, H.; Knopf, B.; Schneider von Deimling, T.; Schellnhuber, H.-J.

    The Earth System is a highly complex system that is often modelled by coupling sev- eral nonlinear submodules. For predicting the climate with these models, the following uncertainties play an essential role: parameter uncertainty, uncertainty in initial con- ditions or model uncertainty. Here we will address uncertainty in initial conditions as well as model uncertainty. As the process of coupling is an important part of model- ing, the main aspect of this work is the investigation of uncertainties that are due to the coupling process. For this study we use conceptual models that, compared to GCMs, have the advantage that the model itself as well as the output can be treated in a mathematically elabo- rated way. As the time for running the model is much shorter, the investigation is also possible for a longer period, e.g. for paleo runs. In consideration of these facts it is feasible to analyse the whole phase space of the model. The process of coupling is investigated by using different methods of examining low order coupled atmosphere-ocean systems. In the dynamical approach a fully coupled system of the two submodules can be compared to a system where one submodule forces the other. For a particular atmosphere-ocean system, based on the Lorenz model for the atmosphere, there can be shown significant differences in the predictability of a forced system depending whether the subsystems are coupled in a linear or a non- linear way. In [1] it is shown that in the linear case the forcing cannot represent the coupling, but in the nonlinear case, that we investigated in our study, the variability and the statistics of the coupled system can be reproduced by the forcing. Another approach to analyse the coupling is to carry out a bifurcation analysis. Here the bifurcation diagram of a single atmosphere system is compared to that of a cou- pled atmosphere-ocean system. Again it can be seen from the different behaviour of the coupled and the uncoupled system, that the

  5. 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,…

  6. Tubular Coupling

    NASA Technical Reports Server (NTRS)

    Rosenbaum, Bernard J. (Inventor)

    2000-01-01

    A system for coupling a vascular overflow graft or cannula to a heart pump. A pump pipe outlet is provided with an external tapered surface which receives the end of a compressible connula. An annular compression ring with a tapered internal bore surface is arranged about the cannula with the tapered internal surface in a facing relationship to the external tapered surface. The angle of inclination of the tapered surfaces is converging such that the spacing between the tapered surfaces decreases from one end of the external tapered surface to the other end thereby providing a clamping action of the tapered surface on a cannula which increases as a function of the length of cannula segment between the tapered surfaces. The annular compression ring is disposed within a tubular locking nut which threadedly couples to the pump and provides a compression force for urging the annular ring onto the cannula between the tapered surfaces. The nut has a threaded connection to the pump body. The threaded coupling to the pump body provides a compression force for the annular ring. The annular ring has an annular enclosure space in which excess cannula material from the compression between the tapered surfaces to "bunch up" in the space and serve as an enlarged annular ring segment to assist holding the cannula in place. The clamped cannula provides a seamless joint connection to the pump pipe outlet where the clamping force is uniformly applied to the cannula because of self alignment of the tapered surfaces. The nut can be easily disconnected to replace the pump if necessary.

  7. 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

  8. 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.

  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. 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.

  11. 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.

  12. Individual differences in behavioural plasticities.

    PubMed

    Stamps, Judy A

    2016-05-01

    Interest in individual differences in animal behavioural plasticities has surged in recent years, but research in this area has been hampered by semantic confusion as different investigators use the same terms (e.g. plasticity, flexibility, responsiveness) to refer to different phenomena. The first goal of this review is to suggest a framework for categorizing the many different types of behavioural plasticities, describe examples of each, and indicate why using reversibility as a criterion for categorizing behavioural plasticities is problematic. This framework is then used to address a number of timely questions about individual differences in behavioural plasticities. One set of questions concerns the experimental designs that can be used to study individual differences in various types of behavioural plasticities. Although within-individual designs are the default option for empirical studies of many types of behavioural plasticities, in some situations (e.g. when experience at an early age affects the behaviour expressed at subsequent ages), 'replicate individual' designs can provide useful insights into individual differences in behavioural plasticities. To date, researchers using within-individual and replicate individual designs have documented individual differences in all of the major categories of behavioural plasticities described herein. Another important question is whether and how different types of behavioural plasticities are related to one another. Currently there is empirical evidence that many behavioural plasticities [e.g. contextual plasticity, learning rates, IIV (intra-individual variability), endogenous plasticities, ontogenetic plasticities) can themselves vary as a function of experiences earlier in life, that is, many types of behavioural plasticity are themselves developmentally plastic. These findings support the assumption that differences among individuals in prior experiences may contribute to individual differences in behavioural

  13. The psychology of suicidal behaviour.

    PubMed

    O'Connor, Rory C; Nock, Matthew K

    2014-06-01

    The causes of suicidal behaviour are not fully understood; however, this behaviour clearly results from the complex interaction of many factors. Although many risk factors have been identified, they mostly do not account for why people try to end their lives. In this Review, we describe key recent developments in theoretical, clinical, and empirical psychological science about the emergence of suicidal thoughts and behaviours, and emphasise the central importance of psychological factors. Personality and individual differences, cognitive factors, social aspects, and negative life events are key contributors to suicidal behaviour. Most people struggling with suicidal thoughts and behaviours do not receive treatment. Some evidence suggests that different forms of cognitive and behavioural therapies can reduce the risk of suicide reattempt, but hardly any evidence about factors that protect against suicide is available. The development of innovative psychological and psychosocial treatments needs urgent attention. PMID:26360404

  14. 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

  15. 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

  16. Preventing aggressive behaviour in dogs.

    PubMed

    Orritt, Rachel

    2016-07-01

    Delegates from around the world met at the University of Lincoln on June 11 and 12 for the third annual UK Dog Bite Prevention and Behaviour conference. The conference, hosted by dog trainer Victoria Stilwell, brings together dog behaviour experts to discuss possible solutions to this public health issue. Rachel Orritt, who has been examining the perceptions, assessment and management of human-directed aggressive behaviour in dogs for her PhD, reports. PMID:27389748

  17. The Association between Bullying Behaviour, Arousal Levels and Behaviour Problems

    ERIC Educational Resources Information Center

    Woods, S.; White, E.

    2005-01-01

    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,…

  18. The working stroke of the myosin II motor in muscle is not tightly coupled to release of orthophosphate from its active site

    PubMed Central

    Caremani, Marco; Melli, Luca; Dolfi, Mario; Lombardi, Vincenzo; Linari, Marco

    2013-01-01

    Skeletal muscle shortens faster against a lower load. This force–velocity relationship is the fundamental determinant of muscle performance in vivo and is due to ATP-driven working strokes of myosin II motors, during their cyclic interactions with the actin filament in each half-sarcomere. Crystallographic studies suggest that the working stroke is associated with the release of phosphate (Pi) and consists of 70 deg tilting of a light-chain domain that connects the catalytic domain of the myosin motor to the myosin tail and filament. However, the coupling of the working stroke with Pi release is still an unsolved question. Using nanometre–microsecond mechanics on skinned muscle fibres, we impose stepwise drops in force on an otherwise isometric contraction and record the isotonic velocity transient, to measure the mechanical manifestation of the working stroke of myosin motors and the rate of its regeneration in relation to the half-sarcomere load and [Pi]. We show that the rate constant of the working stroke is unaffected by [Pi], while the subsequent transition to steady velocity shortening is accelerated. We propose a new chemo-mechanical model that reproduces the transient and steady state responses by assuming that: (i) the release of Pi from the catalytic site of a myosin motor can occur at any stage of the working stroke, and (ii) a myosin motor, in an intermediate state of the working stroke, can slip to the next actin monomer during filament sliding. This model explains the efficient action of muscle molecular motors working as an ensemble in the half-sarcomere. PMID:23878374

  19. 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

  20. Alteration of Fractured Rocks Due to Coupled Chemical and Mechanical Processes: High-Resolution Simulations and Experimental Observations

    NASA Astrophysics Data System (ADS)

    Ameli, Pasha

    Engineering activities such as enhanced geothermal energy production and improved oil recovery techniques are heavily dependent on the permeability of the subsurface, while others such as CO2 sequestration and nuclear waste disposal rely on the efficiency of rock formations as transport barriers. In either case fractures provide the main pathways for fluid flow and transport, especially in rocks with lower matrix porosity. Laboratory experiments aimed at quantifying the chemo-mechanical responses of fractures have shown a range of results, some of which contradict simple conceptual models. For example, under conditions favoring mineral dissolution, where one would expect an overall increase in permeability, experiments show that permeability increases under some conditions and decreases under others. Recent experiments have attempted to link these core-scale observations to the relevant small-scale processes occurring within fractures. Results suggest that the loss of mechanical strength in asperities due to chemical alteration may cause non-uniform deformation and alteration of fracture apertures. However, due to the lack of direct micro-scale measurements of the coupled chemical and mechanical processes that lead to alteration of contacting fracture surfaces, our ability to predict the long-term evolution of fractures is still limited. To explore the processes that control permeability evolution, I developed a computational model that uses micro-scale surface roughness and explicitly couples dissolution and elastic deformation to calculate local alterations in fracture aperture under chemical and mechanical stresses. A depth-averaged algorithm of fracture flow is used to model reactive transport and chemical alteration of the fracture surfaces. Then, I deform the resulting altered fracture-surfaces using an algorithm that calculates the elastic deformation. The results of the model are compared with flow-through experiments conducted on fractured limestone. The

  1. 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

  2. Infant Predictors of Behavioural Inhibition

    ERIC Educational Resources Information Center

    Moehler, Eva; Kagan, Jerome; Oelkers-Ax, Rieke; Brunner, Romuald; Poustka, Luise; Haffner, Johann; Resch, Franz

    2008-01-01

    Behavioural inhibition in the second year of life is a hypothesized predictor for shyness, social anxiety and depression in later childhood, adolescence and even adulthood. To search for the earliest indicators of this fundamental temperamental trait, this study examined whether behavioural characteristics in early infancy can predict behavioural…

  3. Behaviour modification in hyperactive children.

    PubMed

    Weeks, A; Laver-Bradbury, C

    Behaviour problems in pre-school children can be significantly improved by professionals experienced in child behaviour modification techniques. Reported disobedience, temper tantrums and poor concentration in hyperactive children aged three to three-and-a-half years improved significantly in a treatment group, following eight home visits by research health visitors working in a child and family guidance service. PMID:9418516

  4. 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.

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

    PubMed

    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

  6. Behavioural biologists don't agree on what constitutes behaviour

    PubMed Central

    Levitis, Daniel A.; Lidicker, William Z.; Freund, Glenn

    2009-01-01

    Behavioural biology is a major discipline within biology, centred on the key concept of `behaviour.' But how is `behaviour' defined, and how should it be defined? We outline what characteristics we believe a scientific definition should have, and why we think it important that a definition have these traits. We then examine the range of available published definitions for the word. Finding no consensus, we present survey responses from 174 members of three behaviour-focused scientific societies as to their understanding of the term. Here again, we find surprisingly widespread disagreement as to what qualifies as behaviour. Respondents contradict themselves, each other, and published definitions, indicating that they are using individually variable intuitive, rather than codified, meanings of `behaviour.' We offer a new definition, based largely on survey responses: “Behaviour is the internally coordinated responses (actions or inactions) of whole living organisms (individuals or groups) to internal and/or external stimuli, excluding responses more easily understood as developmental changes.” Finally, we discuss the usage, meanings and limitations of this definition. PMID:20160973

  7. 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

  8. Adsorption behaviour of bulgur.

    PubMed

    Erbaş, Mustafa; Aykın, Elif; Arslan, Sultan; Durak, Atike N

    2016-03-15

    The aim of this research was to determine the adsorption behaviour of bulgur. Three different particle sizes (2

  9. 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

  10. 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

  11. 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

  12. Quantitative genetic studies of antisocial behaviour.

    PubMed

    Viding, Essi; Larsson, Henrik; Jones, Alice P

    2008-08-12

    This paper will broadly review the currently available twin and adoption data on antisocial behaviour (AB). It is argued that quantitative genetic research can make a significant contribution to further the understanding of how AB develops. Genetically informative study designs are particularly useful for investigating several important questions such as whether: the heritability estimates vary as a function of assessment method or gender; the relative importance of genetic and environmental influences varies for different types of AB; the environmental risk factors are truly environmental; and genetic vulnerability influences susceptibility to environmental risk. While the current data are not yet directly translatable for prevention and treatment programmes, quantitative genetic research has concrete translational potential. Quantitative genetic research can supplement neuroscience research in informing about different subtypes of AB, such as AB coupled with callous-unemotional traits. Quantitative genetic research is also important in advancing the understanding of the mechanisms by which environmental risk operates. PMID:18434281

  13. 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

  14. 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.

  15. 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.

  16. Behavioural consequences of child abuse

    PubMed Central

    Al Odhayani, Abdulaziz; Watson, William J.; Watson, Lindsay

    2013-01-01

    Abstract Objective To discuss the consequences of abuse on childhood behavioural development, to highlight some behavioural clues that might alert physicians to ongoing child abuse, and to explore the specific role of the family physician in this clinical situation. Sources of information A systematic search was used to review relevant research, clinical review articles, and child protection agency websites. Main message A child’s behaviour is an outward manifestation of inner stability and security. It is a lens through which the family physician can observe the development of the child throughout his or her life. All types of abuse are damaging to children—physically, emotionally, and psychologically—and can cause long-term difficulties with behaviour and mental health development. Family physicians need to be aware of and alert to the indicators of child abuse and neglect so that appropriate interventions can be provided to improve outcomes for those children. Conclusion Child abuse might cause disordered psychological development and behaviour problems. Family physicians have an important role in recognizing behaviour clues that suggest child abuse and in providing help to protect children. PMID:23946022

  17. Topography of vision and behaviour.

    PubMed

    Smolka, Jochen; Hemmi, Jan M

    2009-11-01

    Given the great range of visual systems, tasks and habitats, there is surprisingly little experimental evidence of how visual limitations affect behavioural strategies under natural conditions. Analysing this relationship will require an experimental system that allows for the synchronous measurement of visual cues and visually guided behaviour. The first step in quantifying visual cues from an animal's perspective is to understand the filter properties of its visual system. We examined the first stage of visual processing - sampling by the ommatidial array - in the compound eye of the fiddler crab Uca vomeris. Using an in vivo pseudopupil method we determined sizes and viewing directions of ommatidia and created a complete eye map of optical and sampling resolution across the visual field. Our results reveal five distinct eye regions (ventral, dorsal, frontal, lateral and medial) which exhibit clear differences in the organisation of the local sampling array, in particular with respect to the balance of resolution and contrast sensitivity. We argue that, under global eye space constraints, these regional optimisations reflect the information content and behavioural relevance of the corresponding parts of the visual field. In demonstrating the tight link between visual sampling, visual cues and behavioural strategies, our analysis highlights how the study of natural behaviour and natural stimuli is essential to our understanding and interpretation of the evolution and ecology of animal behaviour and the design of sensory systems. PMID:19837894

  18. 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

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

    PubMed Central

    Sih, Andrew; Del Giudice, Marco

    2012-01-01

    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. PMID:22927575

  20. 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.

  1. 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.

  2. Behavioural medicine in health promotion.

    PubMed

    Kopp, M

    1999-01-01

    Behavioural medicine is a rapidly developing interdisciplinary field that integrates the physiological and psychosocial aspects of human behaviour and applies them to prevention. In the early stage of chronic non-infectious illnesses of great epidemiological significance the most important risk factors are the reversible psychophysiological regulation disturbances. According to the behavioural medicine model depressive symptomatology, hopelessness, anxiety, non-adaptive ways of coping, dysfunctional attitudes are common risk factors in the background of self-destructive behavioural disturbances, such as smoking, alcohol and drug abuse and suicidal behaviour. The basic link between physiological and psychological phenomena is the decision making process, the cognitive appraisal, evaluation of the given situation, which is very subjective and depends on the socialization process. The modern civilised way of life continuously creates situations in which we experience loss of control, and therefore the psychological and physiological balance can only be obtained with great difficulty. Especially under conditions of sudden cultural and socioeconomic transition strengthening adaptive ways of coping and preventing emotional disturbances are fundamental in health promotion. PMID:10943647

  3. 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

  4. 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

  5. Moderators of the intention-behaviour and perceived behavioural control-behaviour relationships for leisure-time physical activity

    PubMed Central

    Amireault, Steve; Godin, Gaston; Vohl, Marie-Claude; Pérusse, Louis

    2008-01-01

    Background Intention is a key determinant of action. However, there is a gap between intention and behavioural performance that remains to be explained. Therefore, the aim of this study was to identify moderators of the intention-behaviour and perceived behavioural control (PBC)- behaviour relationships for leisure-time physical activity. Method This was tested in reference to Ajzen's Theory of Planned Behaviour. A sample of 300 volunteers, 192 women and 108 men, aged 18 to 55, participated in the study. At baseline, the participants completed a self-administrated psychosocial questionnaire assessing Ajzen's theory variables (i.e., intention and perceived behavioural control). The behavioural measure was obtained by mail three months later. Results Multiple hierarchical regression analyses indicated that age and annual income moderated the intention-behaviour and PBC-behaviour relationships. However, in the final model predicting behaviour (R2 = .46), only the interaction term of PBC by annual income (β = .24, p = 0.0003) significantly contributed to the prediction of behaviour along with intention (β = .49, p = 0.0009) and past behaviour (β = .44, p < 0.0001). Conclusion Physical activity promotion programs would benefit not only from focusing on increasing the intention of low intenders, but also from targeting factors that moderate the perceived behavioural control-behaviour relationships. PMID:18241339

  6. 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.

  7. 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

  8. 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

  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

    2015-09-01

    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. 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

  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. Better Behaviour. Building Success through Better Behaviour Series

    ERIC Educational Resources Information Center

    Long, Rob

    2005-01-01

    Many children have all sorts of difficulties in their lives, which set up barriers to learning. This book demonstrates how teachers can help them face personal challenges. It contains: ideas for stress proofing children; guidance on teaching problem-solving skills; and explanations of cognitive behaviour therapy.

  13. 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.…

  14. 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…

  15. 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…

  16. 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.

  17. Systems chemistry: Selecting complex behaviour

    NASA Astrophysics Data System (ADS)

    Bissette, Andrew J.; Fletcher, Stephen P.

    2015-01-01

    Creating chemical systems that can model living systems is far from easy. However, the evolution of oil droplets in water through the application of artificial selective pressure to produce droplets with dramatically different -- yet specific -- behaviours, is an encouraging step in this direction.

  18. 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

  19. 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)

  20. 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

  1. 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.

  2. 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…

  3. 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.

  4. 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

  5. A preliminary study into emergent behaviours in a lattice of interacting nonlinear resonators and oscillators

    NASA Astrophysics Data System (ADS)

    Randrianandrasana, Michel F.; Wei, Xueyong; Lowe, David

    2011-07-01

    Future sensor arrays will be composed of interacting nonlinear components with complex behaviours with no known analytic solutions. This paper provides a preliminary insight into the expected behaviour through numerical and analytical analysis. Specifically, the complex behaviour of a periodically driven nonlinear Duffing resonator coupled elastically to a van der Pol oscillator is investigated as a building block in a 2D lattice of such units with local connectivity. An analytic treatment of the 2-device unit is provided through a two-time-scales approach and the stability of the complex dynamic motion is analysed. The pattern formation characteristics of a 2D lattice composed of these units coupled together through nearest neighbour interactions is analysed numerically for parameters appropriate to a physical realisation through MEMS devices. The emergent patterns of global and cluster synchronisation are investigated with respect to system parameters and lattice size.

  6. 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…

  7. 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…

  8. Self-Directed Behavioural Family Intervention

    ERIC Educational Resources Information Center

    Morawska, Alina; Sanders, Matthew R.

    2006-01-01

    Behavioural family intervention is effective for the prevention and treatment of a wide range of emotional and behavioural problems in children. There is a growing need to address the accessibility of these services. This paper reviews the literature on self-directed interventions designed to help parents manage difficult child behaviours.…

  9. 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

  10. 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…

  11. 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…

  12. [Behaviour of laying hens in aviaries--review. Part 2: Feeding behaviour, reproductive and dust bathing behaviour of chickens].

    PubMed

    Moesta, A; Briese, A; Knierim, U; Hartung, J

    2008-01-01

    This literature review gives information about important behaviour patterns concerning feeding, reproduction and dust bathing of laying hens kept in aviary systems. The behaviour of hens in aviaries is compared to the behaviour of hens living under "close to natural" conditions. Feeding behaviour can be performed to a great extent in aviaries. The same is true for nesting behaviour, while mating behaviour can only be shown in mixed flocks. Dust bathing behaviour in aviaries should be further investigated. Although a litter area is provided and therefore dust bathing is basically possible, further research is needed, to which amount dust bathing behaviour is performed and how it is influenced by composition and height of the dust bathing substrate. Feather pecking and cannibalism can cause more deaths in housing systems with large groups of birds than in cage systems. Considering these results and the results of a first paper dealing with social and resting behaviour, aviaries provide an environment, where hens can perform a large part of their species typical behaviour repertoire. Therefore, under the aspect of behaviour, for laying hens in aviaries the potential to experience good welfare can be evaluated as fairly high. PMID:18265752

  13. Scaling behaviour of entropy estimates

    NASA Astrophysics Data System (ADS)

    Schürmann, Thomas

    2002-02-01

    Entropy estimation of information sources is highly non-trivial for symbol sequences with strong long-range correlations. The rabbit sequence, related to the symbolic dynamics of the nonlinear circle map at the critical point as well as the logistic map at the Feigenbaum point, is known to produce long memory tails. For both dynamical systems the scaling behaviour of the block entropy of order n has been shown to increase ∝log n. In contrast to such probabilistic concepts, we investigate the scaling behaviour of certain non-probabilistic entropy estimation schemes suggested by Lempel and Ziv (LZ) in the context of algorithmic complexity and data compression. These are applied in a sequential manner with the scaling variable being the length N of the sequence. We determine the scaling law for the LZ entropy estimate applied to the case of the critical circle map and the logistic map at the Feigenbaum point in a binary partition.

  14. Static behaviour of induced seismicity

    NASA Astrophysics Data System (ADS)

    Mignan, A.

    2015-12-01

    The standard paradigm to describe seismicity induced by fluid injection is to apply nonlinear diffusion dynamics in a poroelastic medium. I show that the spatiotemporal 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 behaviour 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.

  15. Midbrain circuits for defensive behaviour.

    PubMed

    Tovote, Philip; Esposito, Maria Soledad; Botta, Paolo; Chaudun, Fabrice; Fadok, Jonathan P; Markovic, Milica; Wolff, Steffen B E; Ramakrishnan, Charu; Fenno, Lief; Deisseroth, Karl; Herry, Cyril; Arber, Silvia; Lüthi, Andreas

    2016-06-01

    Survival in threatening situations depends on the selection and rapid execution of an appropriate active or passive defensive response, yet the underlying brain circuitry is not understood. Here we use circuit-based optogenetic, in vivo and in vitro electrophysiological, and neuroanatomical tracing methods to define midbrain periaqueductal grey circuits for specific defensive behaviours. We identify an inhibitory pathway from the central nucleus of the amygdala to the ventrolateral periaqueductal grey that produces freezing by disinhibition of ventrolateral periaqueductal grey excitatory outputs to pre-motor targets in the magnocellular nucleus of the medulla. In addition, we provide evidence for anatomical and functional interaction of this freezing pathway with long-range and local circuits mediating flight. Our data define the neuronal circuitry underlying the execution of freezing, an evolutionarily conserved defensive behaviour, which is expressed by many species including fish, rodents and primates. In humans, dysregulation of this 'survival circuit' has been implicated in anxiety-related disorders. PMID:27279213

  16. 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

  17. 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. PMID:24375977

  18. 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.

  19. The behavioural final common path.

    PubMed

    McFarland, D J; Sibly, R M

    1975-05-15

    In this paper it is argued that any model of the motivational (i.e. reversible) processes governing the behaviour of an animal can be represented by means of isoclines in a multidimensional 'causal-factor space'. The argument is axiomatic, based upon the two prime assumptions: that (1) it is always possible to classify the behavioural repertoire of a species in such a way that the classes are mutually exclusive in the sense that the members of different classes cannot occur simultaneously, and (2) these incompatible actions are uniquely determined by a particular set of causal factors. The isoclines join all points in the space which present a given 'degree of competitiveness' of a particular 'candidate' for overt behavioural expression. The competition between candidates is an inevitable consequence of the fact that animals cannot 'do more than one thing at a time', and is envisaged as taking place in the behavioural final common path. An empirical method of determining the motivational state (i.e. point in causal-factor space) is outlined. This is a 'relative' method, independent of the arbitrary calibration of the axes of the causal-factor space. It is shown that an arbitrary scale of measurement along any two axes of the causal-factor space is all that is necessary for empirical determination of the shape of a motivational isocline. Experiments in which this method has been applied to the measurement of hunger and thirst in doves are outlined, and the results are discussed in terms of their implications for motivation theory in general. PMID:239416

  20. [Genes for extreme violent behaviour?].

    PubMed

    Jordan, Bertrand

    2015-01-01

    A new genetic study focussing on the degree of violence in criminals and using both candidate gene and GWAS approaches finds statistically significant associations of extreme violent behaviour with low activity alleles of monoamine oxydase A (MAOA) and with the CD13 gene. However, the alleles implicated are common in the general population, thus they cannot be causal, and only represent potential indicators of increased risk. PMID:25658738

  1. 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. PMID:23756285

  2. Thermal quench at finite 't Hooft coupling

    NASA Astrophysics Data System (ADS)

    Ebrahim, H.; Ali-Akbari, M.; Heshmatian, S.

    2016-03-01

    Using holography we have studied thermal electric field quench for infinite and finite 't Hooft coupling constant. The set-up we consider here is D7-brane embedded in (α‧ corrected) AdS-black hole background. It is well-known that due to a time-dependent electric field on the probe brane, a time-dependent current will be produced and it will finally relax to its equilibrium value. We have studied the effect of different parameters of the system on equilibration time. As the most important results, for massless fundamental matter, we have observed a universal behaviour in the rescaled equilibration time in the very fast quench regime for different values of the temperature and α‧ correction parameter. It seems that in the slow quench regime the system behaves adiabatically. We have also observed that the equilibration time decreases in finite 't Hooft coupling limit.

  3. Goal desires moderate intention-behaviour relations.

    PubMed

    Prestwich, Andrew; Perugini, Marco; Hurling, Robert

    2008-03-01

    Models such as the Extended Model of Goal-Directed Behaviour and the Theory of Planned Behaviour imply that the impact of one's goals on behaviour is mediated by more proximal determinants. We hypothesize that goals can have a broader and more dynamic impact on behaviour and, specifically, that goal desires can moderate the effect of intentions on behaviour. Four studies addressed this issue by examining the direct and moderated effects of goal desires on behaviour. All of the studies required participants to complete baseline measures and then a follow-up indicator of behaviour. In Study 1 (N=119) that focused on fruit intake, Study 2 (N=123) and Study 3 (N=96) concerned with drinking alcohol and Study 4 (N=109) regarding snack consumption, behavioural intentions were more reliably related to behaviour when goal desires were strong. The results of Study 3 suggested that goal desire stability increases the likelihood of this moderator effect emerging and Study 4 revealed that this effect was not suppressed by intention stability. The findings suggest that goals and behavioural intentions can operate simultaneously and jointly influence action, a view that contradicts predictions that the effects of goals are fully mediated by more proximal behavioural determinants. PMID:17594757

  4. 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

  5. Symbiont infection affects aphid defensive behaviours.

    PubMed

    Dion, Emilie; Polin, Sarah Erika; Simon, Jean-Christophe; Outreman, Yannick

    2011-10-23

    Aphids harbour both an obligate bacterial symbiont, Buchnera aphidicola, and a wide range of facultative ones. Facultative symbionts can modify morphological, developmental and physiological host traits that favour their spread within aphid populations. We experimentally investigated the idea that symbionts may also modify aphid behavioural traits to enhance their transmission. Aphids exhibit many behavioural defences against enemies. Despite their benefits, these behaviours have some associated costs leading to reduction in aphid reproduction. Some aphid individuals harbour a facultative symbiont Hamiltonella defensa that provides protection against parasitoids. By analysing aphid behaviours in the presence of parasitoids, we showed that aphids infected with H. defensa exhibited reduced aggressiveness and escape reactions compared with uninfected aphids. The aphid and the symbiont have both benefited from these behavioural changes: both partners reduced the fitness decrements associated with the behavioural defences. Such symbiont-induced changes of behavioural defences may have consequences for coevolutionary processes between host organisms and their enemies. PMID:21490007

  6. Three tooth kinematic coupling

    DOEpatents

    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.

  7. 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.

  8. 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

  9. Behavioural perspectives on piglet survival.

    PubMed

    Fraser, D

    1990-01-01

    Litters of domestic piglets show strong sibling competition, large differences among litter-mates in birth weight and rate of growth, and, in the absence of human intervention, a high mortality rate. This combination of traits suggests that pigs are using a reproductive strategy similar to that of certain bird species which produce one or more small 'spare' young whose death or survival is determined by sibling competition. Death through competition is natural in such species. Prevention of death requires the early identification and separate rearing of unsuccessful competitors. The major behavioural pathways leading to piglet deaths are considered to be malnutrition through unsuccessful suckling behaviour, and crushing of piglets by the sow. Crushing involves two distinct behavioural sequences: posterior crushing (beneath the sow's hind quarters) and ventral crushing (beneath the udder and rib cage). Farrowing crates are designed to prevent posterior but not ventral crushing. Malnourished piglets appear to be more vulnerable to crushing, perhaps because persistent suckling attempts cause them to spend more time near the sow. Prevention of crushing thus requires a reduction in malnutrition, not merely restriction of the sow's movements. Under certain conditions, dehydration may be an important but neglected aspect of malnutrition. Some litters of piglets have much higher death losses than others, presumably because of risk factors that apply to the litter as a whole. Early malnutrition, resulting from hypogalactia in the sow in the first days after farrowing, appears to be an important risk factor. Farrowing difficulties leading to piglet hypoxia during the birth process may be another. Risk factors that affect whole litters deserve greater emphasis in future research. PMID:2192051

  10. Vibroacoustic Behaviour of a Simplified Musical Wind Instrument

    NASA Astrophysics Data System (ADS)

    Gautier, F.; Tahani, N.

    1998-05-01

    The influence of the wall vibrations of a musical wind instrument on tone quality remains an open question. In order to quantify the effects of these vibrations, a model of the vibroacoustic behaviour of a simplified instrument (clarinet-like instrument) is proposed. The reed, which is represented by mechanical and acoustical harmonic sources, excites a thin cylindrical shell, filled and surrounded with air. The sound radiation due to wall vibrations has two origins, which are decoupled in the model making use of artificial baffles. The first one corresponds to the direct radiation of the shell in the external fluid. The second one is created by the internal radiation of the shell, which is then radiated outside the tube, through its open end. Three kinds of vibroacoustic couplings are involved in this situation: structure/internal fluid, structure/external fluid and inter-modal acoustic coupling due to sound radiation at the open end of the duct. A modal formulation of the problem is proposed which takes into account these three couplings. Impedances describing the shifts of the internal acoustic resonance frequencies due to the effects of the three kinds of couplings are given and permit one to quantify the wall vibrations effect.

  11. 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

  12. 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.

  13. 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

  14. 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.

  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. 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.

  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. Bibliographic Coupling: A Review

    ERIC Educational Resources Information Center

    Weinberg, Bella Hass

    1974-01-01

    The theory and practical applications of bibliographic coupling are reviewed. The reviewer takes issue with the use of bibliographic coupling for information retrieval and automatic classification on logical grounds, and for reasons relating to uncontrolled citation practices. The usefulness of the procedure for the study of the science of science…

  19. Gear Spline Coupling Program

    Energy Science and Technology Software Center (ESTSC)

    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. Exponentially modified QCD coupling

    SciTech Connect

    Cvetic, Gorazd; Valenzuela, Cristian

    2008-04-01

    We present a specific class of models for an infrared-finite analytic QCD coupling, such that at large spacelike energy scales the coupling differs from the perturbative one by less than any inverse power of the energy scale. This condition is motivated by the Institute for Theoretical and Experimental Physics operator product expansion philosophy. Allowed by the ambiguity in the analytization of the perturbative coupling, the proposed class of couplings has three parameters. In the intermediate energy region, the proposed coupling has low loop-level and renormalization scheme dependence. The present modification of perturbative QCD must be considered as a phenomenological attempt, with the aim of enlarging the applicability range of the theory of the strong interactions at low energies.

  1. Ground energy coupling

    NASA Astrophysics Data System (ADS)

    Metz, P. D.

    The feasibility of ground coupling for various heat pump systems was investigated. Analytical heat flow models were developed to approximate design ground coupling devices for use in solar heat pump space conditioning systems. A digital computer program called GROCS (GRound Coupled Systems) was written to model 3-dimensional underground heat flow in order to simulate the behavior of ground coupling experiments and to provide performance predictions which have been compared to experimental results. GROCS also has been integrated with TRNSYS. Soil thermal property and ground coupling device experiments are described. Buried tanks, serpentine earth coils in various configurations, lengths and depths, and sealed vertical wells are being investigated. An earth coil used to heat a house without use of resistance heating is described.

  2. 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.

  3. Cooperative behaviour in complex systems

    NASA Astrophysics Data System (ADS)

    Karsai, Márton

    2009-07-01

    In my PhD thesis I studied cooperative phenomena arise in complex systems using the methods of statistical and computational physics. The aim of my work was also to study the critical behaviour of interacting many-body systems during their phase transitions and describe their universal features analytically and by means of numerical calculations. In order to do so I completed studies in four different subjects. My first investigated subject was a study of non-equilibrium phase transitions in weighted scale-free networks. The second problem I examined was the ferromagnetic random bond Potts model with large values of q on evolving scale-free networks which problem is equivalent to an optimal cooperation problem. The third examined problem was related to the large-q sate random bond Potts model also and I examined the critical density of clusters which touched a certain border of a perpendicular strip like geometry and expected to hold analytical forms deduced from conformal invariance. The last investigated problem was a study of the non-equilibrium dynamical behaviour of the antiferromagnetic Ising model on two-dimensional triangular lattice at zero temperature in the absence of external field and at the Kosterlitz-Thouless phase transition point.

  4. 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.

  5. Measuring tactical behaviour in football.

    PubMed

    Sampaio, J; Maçãs, V

    2012-05-01

    The present study explored how football players' dynamic positional data can be used to assess tactical behaviour by measuring movement patterns and inter-player coordination. A pre post-test design was used to assess the effects of a 13-week constructivist and cognitivist training program by measuring behaviour in a 5 × 5 football small-sided game, played on a 60 × 40 m outdoor natural turf pitch. Data was captured at 5 Hz by GPS devices (SPI Pro, GPSports, Canberra, Australia) and analysed with non-linear signal processing methods. Approximate entropy values were lower in post-test situations suggesting that these time series became more regular with increasing expertise in football. Relative phase post-test values showed frequent periods with a clear trend to moving in anti-phase, as measured by players' distance to the centre of the team. These advances may open new research topics under the tactical scope and allow narrowing the gap between sports sciences and sports coaching. PMID:22377947

  6. The epitheliome: agent-based modelling of the social behaviour of cells.

    PubMed

    Walker, D C; Southgate, J; Hill, G; Holcombe, M; Hose, D R; Wood, S M; Mac Neil, S; Smallwood, R H

    2004-01-01

    We have developed a new computational modelling paradigm for predicting the emergent behaviour resulting from the interaction of cells in epithelial tissue. As proof-of-concept, an agent-based model, in which there is a one-to-one correspondence between biological cells and software agents, has been coupled to a simple physical model. Behaviour of the computational model is compared with the growth characteristics of epithelial cells in monolayer culture, using growth media with low and physiological calcium concentrations. Results show a qualitative fit between the growth characteristics produced by the simulation and the in vitro cell models. PMID:15351133

  7. 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

  8. 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

  9. 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

  10. 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

  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. 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

  13. 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. PMID:23008918

  14. NEUROSIS AND SEXUAL BEHAVIOUR IN MEN

    PubMed Central

    Kumar, Sudhir; Agarwal, A.K.; Trivedi, J.K.

    1983-01-01

    SUMMARY Relationship of neurosis and sexual behaviour has been a matter of dispute till date. In the present study sexual behaviour of 40 married neurotics and 22 matched healthy control males was studied. Sexual behaviour of neurotics was similar to control subjects before the commencement of neurotic illness. But after the onset of the neurotic illness subjects showed significant decrease in frequency of coitus, sexual satisfaction and sexual adequacy in comparison to their pre illness behaviour as well as from healthy controls. PMID:21847285

  15. Methods of Measurement in epidemiology: Sedentary Behaviour

    PubMed Central

    Atkin, Andrew J; Gorely, Trish; Clemes, Stacy A; Yates, Thomas; Edwardson, Charlotte; Brage, Soren; Salmon, Jo; Marshall, Simon J; Biddle, Stuart JH

    2012-01-01

    Background Research examining sedentary behaviour as a potentially independent risk factor for chronic disease morbidity and mortality has expanded rapidly in recent years. Methods We present a narrative overview of the sedentary behaviour measurement literature. Subjective and objective methods of measuring sedentary behaviour suitable for use in population-based research with children and adults are examined. The validity and reliability of each method is considered, gaps in the literature specific to each method identified and potential future directions discussed. Results To date, subjective approaches to sedentary behaviour measurement, e.g. questionnaires, have focused predominantly on TV viewing or other screen-based behaviours. Typically, such measures demonstrate moderate reliability but slight to moderate validity. Accelerometry is increasingly being used for sedentary behaviour assessments; this approach overcomes some of the limitations of subjective methods, but detection of specific postures and postural changes by this method is somewhat limited. Instruments developed specifically for the assessment of body posture have demonstrated good reliability and validity in the limited research conducted to date. Miniaturization of monitoring devices, interoperability between measurement and communication technologies and advanced analytical approaches are potential avenues for future developments in this field. Conclusions High-quality measurement is essential in all elements of sedentary behaviour epidemiology, from determining associations with health outcomes to the development and evaluation of behaviour change interventions. Sedentary behaviour measurement remains relatively under-developed, although new instruments, both objective and subjective, show considerable promise and warrant further testing. PMID:23045206

  16. [Recognizing and assessing aggressive behaviour in dogs].

    PubMed

    Schalke, E; Hackbarth, H

    2006-03-01

    Within the population the sensitivity to aggressive behaviour in dogs has increased. The authorities are confronted with a problem: if any incident occurs it is their task to decide whether the dogs involved constitute a threat to other people or whether the charge is only the result of a quarrel between neighbours. For this reason, an examination of the dogs with regard to their aggressive behaviour is necessary. Seen from the biological point of view, aggressive behaviour is one of four possibilities a dog can chose from to solve a conflict. The dog's intention in showing aggressive behaviour is to eliminate disturbances and to maintain a distance in space and time. Aggressive behaviour might also be necessary to acquire or defend resources essential to the dog's life. This is to secure its survival and its success in reproduction. One can see from this that aggressive behaviour is a very important and biologically necessary adjustment factor. However, when living together with man aggressive behaviour might become a problem. For the assessment and the therapy of the problem it is necessary to exa-mine the behaviour shown by the dog with regard to its cause. To be able to do this an exact anamnesis, a medical check, and an examination of the dog on the basis of its display in special situations are necessary. For this reason, exclusively veterinarians with a special further education in the field of behaviour should carry out the examination of dogs. PMID:16669189

  17. 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. PMID:23744062

  18. 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…

  19. 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.

  20. 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

  1. 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…

  2. Person Focused Training: A Model for Delivering Positive Behavioural Supports to People with Challenging Behaviours

    ERIC Educational Resources Information Center

    McClean, B.; Dench, C.; Grey, I.; Shanahan, S.; Fitzsimons, E.; Hendler, J.; Corrigan, M.

    2005-01-01

    Person Focused Training is introduced as a model of service delivery for people with severe challenging behaviours. It is defined as training and supporting staff to conduct functional assessments and to design and implement positive behavioural support for specific individuals with challenging behaviours. Longitudinal outcome data are presented…

  3. 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…

  4. Testing the bi-dimensional effects of attitudes on behavioural intentions and subsequent behaviour.

    PubMed

    Elliott, Mark A; Brewster, Sarah E; Thomson, James A; Malcolm, Carly; Rasmussen, Susan

    2015-11-01

    Attitudes are typically treated as unidimensional predictors of both behavioural intentions and subsequent behaviour. On the basis of previous research showing that attitudes comprise two independent, positive and negative dimensions, we hypothesized that attitudes would be bi-dimensional predictors of both behavioural intentions and subsequent behaviour. We focused on health-risk behaviours. We therefore also hypothesized that the positive dimension of attitude (evaluations of positive behavioural outcomes) would better predict both behavioural intentions and subsequent behaviour than would the negative dimension, consistent with the positivity bias/offset principle. In Study 1 (cross sectional design), N = 109 university students completed questionnaire measures of their intentions to binge-drink and the positive and negative dimensions of attitude. Consistent with the hypotheses, both attitude dimensions independently predicted behavioural intentions and the positive dimension was a significantly better predictor than was the negative dimension. The same pattern of findings emerged in Study 2 (cross sectional design; N = 186 university students) when we predicted intentions to binge-drink, smoke and consume a high-fat diet. Similarly, in Study 3 (prospective design; N = 1,232 speed limit offenders), both the positive and negative dimensions of attitude predicted subsequent (6-month post-baseline) speeding behaviour on two different road types and the positive dimension was the better predictor. The implications for understanding the motivation of behaviour and the development of behaviour-change interventions are discussed. PMID:25440892

  5. Interlayer exchange coupling effect of L1(0) CoPt based exchange coupled composite media.

    PubMed

    Yang, Yang; Pandey, K K M; Chen, J S; Chow, G M; Hu, J F

    2011-03-01

    In this work, effects of exchange coupling of soft magnetic layer on switching field and magnetization reversal behaviour of CoPt-SiO2(soft)/CoPt-SiO2(hard) exchange coupled media were investigated. With increasing the thickness of the soft layer, both the coercivity and magnetization squareness of composite media decreased. Soft layer thickness 4 nm and below was more effective to significantly reduce the switching field than that above 4 nm. More incoherent switching behavior was observed with increasing soft layer thickness. PMID:21449436

  6. On contextuality in behavioural data.

    PubMed

    Dzhafarov, Ehtibar N; Kujala, Janne V; Cervantes, Víctor H; Zhang, Ru; Jones, Matt

    2016-05-28

    Dzhafarovet al.(Dzhafarovet al.2016Phil. Trans. R. Soc. A374, 20150099. (doi:10.1098/rsta.2015.0099)) reviewed several behavioural datasets imitating the formal design of the quantum-mechanical contextuality experiments. The conclusion was that none of these datasets exhibited contextuality if understood in the generalized sense proposed by Dzhafarovet al.(2015Found. Phys.7, 762-782. (doi:10.1007/s10701-015-9882-9)), while the traditional definition of contextuality does not apply to these data because they violate the condition of consistent connectedness (also known as marginal selectivity, no-signalling condition, no-disturbance principle, etc.). In this paper, we clarify the relationship between (in)consistent connectedness and (non)contextuality, as well as between the traditional and extended definitions of (non)contextuality, using as an example the Clauser-Horn-Shimony-Holt inequalities originally designed for detecting contextuality in entangled particles. PMID:27091164

  7. Tribological Behaviour of Kfre Composite

    NASA Astrophysics Data System (ADS)

    Chin, C. W.; Yousif, B. F.

    This paper presents an attempt to use kenaf fibres as reinforcement for tribo-polymeric composite. Kenaf fibres reinforced epoxy (KFRE) composite was fabricated using a closed mould technique associated with vacuum system. Adhesive wear and frictional behaviour of the composite and neat epoxy (NE) were studied against polished stainless steel counterface using a newly developed block-on-disc (BOD) machine at 50N applied load, sliding distances (0-4.2 km) and sliding velocities of 2.8 m/s. The morphology of the worn surfaces of the composite and NE was studied using a scanning electron microscope (SEM). The result revealed that the longer the sliding distance is, the higher the weight loss. Up to 70% reduction in the weight loss was achieved when the epoxy was reinforced with the kenaf fibres. The wear mechanism was predominated by plastic deformation, in the resinous regions and debonding of fibres.

  8. 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

  9. 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

  10. 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