Science.gov

Sample records for small coupling behaviour

  1. 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

  2. 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.

  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. 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.

  5. Small quantum absorption refrigerator with reversed couplings.

    PubMed

    Silva, Ralph; Skrzypczyk, Paul; Brunner, Nicolas

    2015-07-01

    Small quantum absorption refrigerators have recently attracted renewed attention. Here we present a missing design of a two-qubit fridge, the main feature of which is that one of the two machine qubits is itself maintained at a temperature colder than the cold bath. This is achieved by "reversing" the couplings to the baths compared to previous designs, where only a transition is maintained cold. We characterize the working regime and the efficiency of the fridge. We demonstrate the soundness of the model by deriving and solving a master equation. Finally, we discuss the performance of the fridge, in particular the heat current extracted from the cold bath. We show that our model performs comparably to the standard three-level quantum fridge and thus appears appealing for possible implementations of nanoscale thermal machines. PMID:26274153

  6. Small quantum absorption refrigerator with reversed couplings

    NASA Astrophysics Data System (ADS)

    Silva, Ralph; Skrzypczyk, Paul; Brunner, Nicolas

    2015-07-01

    Small quantum absorption refrigerators have recently attracted renewed attention. Here we present a missing design of a two-qubit fridge, the main feature of which is that one of the two machine qubits is itself maintained at a temperature colder than the cold bath. This is achieved by "reversing" the couplings to the baths compared to previous designs, where only a transition is maintained cold. We characterize the working regime and the efficiency of the fridge. We demonstrate the soundness of the model by deriving and solving a master equation. Finally, we discuss the performance of the fridge, in particular the heat current extracted from the cold bath. We show that our model performs comparably to the standard three-level quantum fridge and thus appears appealing for possible implementations of nanoscale thermal machines.

  7. Small hive beetles survive in honeybee prisons by behavioural mimicry.

    PubMed

    Ellis, J D; Pirk, C W W; Hepburn, H R; Kastberger, G; Elzen, P J

    2002-07-01

    We report the results of a simple experiment to determine whether honeybees feed their small hive beetle nest parasites. Honeybees incarcerate the beetles in cells constructed of plant resins and continually guard them. The longevity of incarcerated beetles greatly exceeds their metabolic reserves. We show that survival of small hive beetles derives from behavioural mimicry by which the beetles induce the bees to feed them trophallactically. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at htpp://dx.doi.org/10.1007/s00114-002-0326-y. PMID:12216866

  8. Small hive beetles survive in honeybee prisons by behavioural mimicry

    NASA Astrophysics Data System (ADS)

    Ellis, J. D.; Pirk, C. W. W.; Hepburn, H. R.; Kastberger, G.; Elzen, P. J.

    2002-05-01

    We report the results of a simple experiment to determine whether honeybees feed their small hive beetle nest parasites. Honeybees incarcerate the beetles in cells constructed of plant resins and continually guard them. The longevity of incarcerated beetles greatly exceeds their metabolic reserves. We show that survival of small hive beetles derives from behavioural mimicry by which the beetles induce the bees to feed them trophallactically. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at htpp://dx.doi.org/10.1007/s00114-002-0326-y.

  9. Age and aggregation trigger mating behaviour in the small hive beetle, Aethina tumida (Nitidulidae)

    NASA Astrophysics Data System (ADS)

    Mustafa, Sandra G.; Spooner-Hart, Robert; Duncan, Michael; Pettis, Jeffery S.; Steidle, Johannes L. M.; Rosenkranz, Peter

    2015-10-01

    This study aimed to investigate the poorly documented reproductive behaviour of the small hive beetle, Aethina tumida (Nitidulidae), a honey bee ( Apis mellifera) parasite. We described the mating behaviour in detail and tested the hypothesis that beetle aggregation plays a vital role in mating in this species. Gender preference was examined in the context of age-dependency and possible chemical communication. Beetles started mating at a high frequency 18 days after emergence from the soil but only if they were aggregated ( p < 0.001); mating was infrequent when beetles were paired. Males in aggregation also tried to copulate with males and only copulated more frequently with females at 18 days after emergence from soil ( p < 0.001) in contrast to newly emerged, 7-day-old and 60-day-old beetles. Males and females spent more time in social contact with the opposite sex ( p < 0.01) when they were 18 days old in contrast to 7-day-old beetles. Filter papers which had been in contact with 21-day-old beetles were highly attractive to similar-aged beetles of the opposite sex ( p < 0.01). This suggests that chemical substances produced by the beetles themselves play a role in mating. Mating behaviour was characterised by a short pre-copulation courtship and female aggression towards other females and copulating couples. Both behaviours may be indicative of cryptic female choice. Delayed onset of reproductive behaviour is typical of many polygamous species, whilst the indispensability of aggregation for onset of sexual behaviour seems to be a feature unique to A. tumida. Both strategies support mass reproduction in this parasitic species, enabling A. tumida to overcome its honey bee host colony, and are probably triggered by chemotactic cues.

  10. Age and aggregation trigger mating behaviour in the small hive beetle, Aethina tumida (Nitidulidae).

    PubMed

    Mustafa, Sandra G; Spooner-Hart, Robert; Duncan, Michael; Pettis, Jeffery S; Steidle, Johannes L M; Rosenkranz, Peter

    2015-10-01

    This study aimed to investigate the poorly documented reproductive behaviour of the small hive beetle, Aethina tumida (Nitidulidae), a honey bee (Apis mellifera) parasite. We described the mating behaviour in detail and tested the hypothesis that beetle aggregation plays a vital role in mating in this species. Gender preference was examined in the context of age-dependency and possible chemical communication. Beetles started mating at a high frequency 18 days after emergence from the soil but only if they were aggregated (p < 0.001); mating was infrequent when beetles were paired. Males in aggregation also tried to copulate with males and only copulated more frequently with females at 18 days after emergence from soil (p < 0.001) in contrast to newly emerged, 7-day-old and 60-day-old beetles. Males and females spent more time in social contact with the opposite sex (p < 0.01) when they were 18 days old in contrast to 7-day-old beetles. Filter papers which had been in contact with 21-day-old beetles were highly attractive to similar-aged beetles of the opposite sex (p < 0.01). This suggests that chemical substances produced by the beetles themselves play a role in mating. Mating behaviour was characterised by a short pre-copulation courtship and female aggression towards other females and copulating couples. Both behaviours may be indicative of cryptic female choice. Delayed onset of reproductive behaviour is typical of many polygamous species, whilst the indispensability of aggregation for onset of sexual behaviour seems to be a feature unique to A. tumida. Both strategies support mass reproduction in this parasitic species, enabling A. tumida to overcome its honey bee host colony, and are probably triggered by chemotactic cues.. PMID:26286322

  11. Coherence Resonance of Small World Networks with Adaptive Coupling

    NASA Astrophysics Data System (ADS)

    Miyakawa, Kenji

    2015-06-01

    The phenomenon of coherence resonance (CR) in small world networks with adaptive coupling is investigated by modeling a real experimental situation with a photosensitive Belousov-Zhabotinsky reaction. We show that both spatial synchronization and temporal coherence of noise-induced firings can be considerably improved by adjusting control parameters, such as the degree of connectivity and the coupling strength. A small fraction of possible long-range connections is enough to obtain a great enhancement in CR.

  12. Synchronization of Coupled Oscillators on Newman Watts Small-World Networks

    NASA Astrophysics Data System (ADS)

    Guan, Jian-Yue; Xu, Xin-Jian; Wu, Zhi-Xi; Wang, Ying-Hai

    2006-06-01

    We investigate the collection behaviour of coupled phase oscillators on Newman-Watts small-world networks in one and two dimensions. Each component of the network is assumed as an oscillator and each interacts with the others following the Kuramoto model. We then study the onset of global synchronization of phases and frequencies based on dynamic simulations and finite-size scaling. Both the phase and frequency synchronization are observed to emerge in the presence of a tiny fraction of shortcuts and enhanced with the increases of nearest neighbours and lattice dimensions.

  13. 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.

  14. Experimental multistable states for small network of coupled pendula.

    PubMed

    Dudkowski, Dawid; Grabski, Juliusz; Wojewoda, Jerzy; Perlikowski, Przemyslaw; Maistrenko, Yuri; Kapitaniak, Tomasz

    2016-01-01

    Chimera states are dynamical patterns emerging in populations of coupled identical oscillators where different groups of oscillators exhibit coexisting synchronous and incoherent behaviors despite homogeneous coupling. Although these states are typically observed in the large ensembles of oscillators, recently it has been shown that so-called weak chimera states may occur in the systems with small numbers of oscillators. Here, we show that similar multistable states demonstrating partial frequency synchronization, can be observed in simple experiments with identical mechanical oscillators, namely pendula. The mathematical model of our experiment shows that the observed multistable states are controlled by elementary dynamical equations, derived from Newton's laws that are ubiquitous in many physical and engineering systems. Our finding suggests that multistable chimera-like states are observable in small networks relevant to various real-world systems. PMID:27445038

  15. Experimental multistable states for small network of coupled pendula

    PubMed Central

    Dudkowski, Dawid; Grabski, Juliusz; Wojewoda, Jerzy; Perlikowski, Przemyslaw; Maistrenko, Yuri; Kapitaniak, Tomasz

    2016-01-01

    Chimera states are dynamical patterns emerging in populations of coupled identical oscillators where different groups of oscillators exhibit coexisting synchronous and incoherent behaviors despite homogeneous coupling. Although these states are typically observed in the large ensembles of oscillators, recently it has been shown that so-called weak chimera states may occur in the systems with small numbers of oscillators. Here, we show that similar multistable states demonstrating partial frequency synchronization, can be observed in simple experiments with identical mechanical oscillators, namely pendula. The mathematical model of our experiment shows that the observed multistable states are controlled by elementary dynamical equations, derived from Newton’s laws that are ubiquitous in many physical and engineering systems. Our finding suggests that multistable chimera-like states are observable in small networks relevant to various real-world systems. PMID:27445038

  16. Experimental multistable states for small network of coupled pendula

    NASA Astrophysics Data System (ADS)

    Dudkowski, Dawid; Grabski, Juliusz; Wojewoda, Jerzy; Perlikowski, Przemyslaw; Maistrenko, Yuri; Kapitaniak, Tomasz

    2016-07-01

    Chimera states are dynamical patterns emerging in populations of coupled identical oscillators where different groups of oscillators exhibit coexisting synchronous and incoherent behaviors despite homogeneous coupling. Although these states are typically observed in the large ensembles of oscillators, recently it has been shown that so-called weak chimera states may occur in the systems with small numbers of oscillators. Here, we show that similar multistable states demonstrating partial frequency synchronization, can be observed in simple experiments with identical mechanical oscillators, namely pendula. The mathematical model of our experiment shows that the observed multistable states are controlled by elementary dynamical equations, derived from Newton’s laws that are ubiquitous in many physical and engineering systems. Our finding suggests that multistable chimera-like states are observable in small networks relevant to various real-world systems.

  17. Hidden from view: coupled dark sector physics and small scales

    NASA Astrophysics Data System (ADS)

    Elahi, Pascal J.; Lewis, Geraint F.; Power, Chris; Carlesi, Edoardo; Knebe, Alexander

    2015-09-01

    We study cluster mass dark matter (DM) haloes, their progenitors and surroundings in a coupled dark matter-dark energy (DE) model and compare it to quintessence and Λ cold dark matter (ΛCDM) models with adiabatic zoom simulations. When comparing cosmologies with different expansions histories, growth functions and power spectra, care must be taken to identify unambiguous signatures of alternative cosmologies. Shared cosmological parameters, such as σ8, need not be the same for optimal fits to observational data. We choose to set our parameters to ΛCDM z = 0 values. We find that in coupled models, where DM decays into DE, haloes appear remarkably similar to ΛCDM haloes despite DM experiencing an additional frictional force. Density profiles are not systematically different and the subhalo populations have similar mass, spin, and spatial distributions, although (sub)haloes are less concentrated on average in coupled cosmologies. However, given the scatter in related observables (V_max,R_{V_max}), this difference is unlikely to distinguish between coupled and uncoupled DM. Observations of satellites of Milky Way and M31 indicate a significant subpopulation reside in a plane. Coupled models do produce planar arrangements of satellites of higher statistical significance than ΛCDM models; however, in all models these planes are dynamically unstable. In general, the non-linear dynamics within and near large haloes masks the effects of a coupled dark sector. The sole environmental signature we find is that small haloes residing in the outskirts are more deficient in baryons than their ΛCDM counterparts. The lack of a pronounced signal for a coupled dark sector strongly suggests that such a phenomena would be effectively hidden from view.

  18. 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

  19. Changing the Environmental Behaviour of Small Business Owners: The Business Case

    ERIC Educational Resources Information Center

    Walker, Beth; Redmond, Janice

    2014-01-01

    The importance of the environment is something of a cracked record to many small business owners, as historically any calls to business to change or improve their practices or behaviours were from the "environmental" or "green" perspective, rather than from a business perspective. As a consequence, many small businesses have…

  20. 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.

  1. Small core fiber coupled 60-W laser diode

    NASA Astrophysics Data System (ADS)

    Fernie, Douglas P.; Mannonen, Ilkka; Raven, Anthony L.

    1995-05-01

    Semiconductor laser diodes are compact, efficient and reliable sources of laser light and 25 W fiber coupled systems developed by Diomed have been in clinical use for over three years. For certain applications, particularly in the treatment of benign prostatic hyperplasia and flexible endoscopy, higher powers are desirable. In these applications the use of flexible optical fibers of no more than 600 micrometers core diameter is essential for compatibility with most commercial delivery fibers and instrumentation. A high power 60 W diode laser system for driving these small core fibers has been developed. The design requirements for medical applications are analyzed and system performance and results of use in gastroenterology and urology with small core fibers will be presented.

  2. Sports teams as complex adaptive systems: manipulating player numbers shapes behaviours during football small-sided games.

    PubMed

    Silva, Pedro; Vilar, Luís; Davids, Keith; Araújo, Duarte; Garganta, Júlio

    2016-01-01

    Small-sided and conditioned games (SSCGs) in sport have been modelled as complex adaptive systems. Research has shown that the relative space per player (RSP) formulated in SSCGs can impact on emergent tactical behaviours. In this study we adopted a systems orientation to analyse how different RSP values, obtained through manipulations of player numbers, influenced four measures of interpersonal coordination observed during performance in SSCGs. For this purpose we calculated positional data (GPS 15 Hz) from ten U-15 football players performing in three SSCGs varying in player numbers (3v3, 4v4 and 5v5). Key measures of SSCG system behaviours included values of (1) players' dispersion, (2) teams' separateness, (3) coupling strength and time delays between participants' emerging movements, respectively. Results showed that values of participants' dispersion increased, but the teams' separateness remained identical across treatments. Coupling strength and time delay also showed consistent values across SSCGs. These results exemplified how complex adaptive systems, like football teams, can harness inherent degeneracy to maintain similar team spatial-temporal relations with opponents through changes in inter-individual coordination modes (i.e., players' dispersion). The results imply that different team behaviours might emerge at different ratios of field dimension/player numbers. Therefore, sport pedagogists should carefully evaluate the effects of changing RSP in SSCGs as a way of promoting increased or decreased pressure on players. PMID:27026887

  3. Experiments with a small behaviour controlled planetary rover

    NASA Technical Reports Server (NTRS)

    Miller, David P.; Desai, Rajiv S.; Gat, Erann; Ivlev, Robert; Loch, John

    1993-01-01

    A series of experiments that were performed on the Rocky 3 robot is described. Rocky 3 is a small autonomous rover capable of navigating through rough outdoor terrain to a predesignated area, searching that area for soft soil, acquiring a soil sample, and depositing the sample in a container at its home base. The robot is programmed according to a reactive behavior control paradigm using the ALFA programming language. This style of programming produces robust autonomous performance while requiring significantly less computational resources than more traditional mobile robot control systems. The code for Rocky 3 runs on an eight bit processor and uses about ten k of memory.

  4. 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

  5. Timescales for exploratory tactical behaviour in football small-sided games.

    PubMed

    Ric, Angel; Hristovski, Robert; Gonçalves, Bruno; Torres, Lorena; Sampaio, Jaime; Torrents, Carlota

    2016-09-01

    The aim of this study was to identify the dynamics of tactical behaviour emerging on different timescales in football small-sided games and to quantify short- and long-term exploratory behaviour according to the number of opponents. Two teams of four professional male footballers played small-sided games against two different teams with a variable number of opponents (3, 5 and 7). Data were collected using a combination of systematic observation and a non-differential global positioning system (15 Hz). The temporal diversity and structural flexibility of the players were determined by calculating the dynamic overlap order parameter q, entropy and trapping strength. Analysis of the exploratory dynamics revealed two different timescales, forming a different metastable landscape of action for each constraint. Fast dynamics lasted on average a few seconds and consisted of changes in tactical patterns. The long timescale corresponded to the shared tasks of offence and defence lasting tens of seconds. The players' tactical diversity decreased with an increasing number of opponents, especially in defence. Manipulating numerical imbalance is likely to promote changes in the diversity, unpredictability and flexibility of tactical solutions. The fact that the temporally nested structure of constraints shaped the emergence of tactical behaviour provides a new rationale for practice task design. The manipulation of numerical imbalance on the timescale of a few tens of seconds, on which the exploratory behaviour of players saturates, may help coaches to optimise the exploratory efficiency of the small-sided games. PMID:26758958

  6. 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

  7. 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.

  8. Small spatial and fast temporal ionosphere-magnetosphere coupling processes

    NASA Astrophysics Data System (ADS)

    Zhu, Hua

    2000-09-01

    I have developed a two-dimensional, three-fluid model (electrons, ions and neutrals) to simulate small-scale magnetosphere-ionosphere coupling processes. The code includes ionization and recombination processes, the Hall term in Ohm's law, and various heat sources in the energy equations. The electro-dynamic response and the evolution of the collision frequencies are treated self- consistently in a height resolved ionosphere. The model allows for the propagation of Alfvén waves. The simulation is particularly suited for fast temporal variations and small spatial scale ionospheric structures associated with filamentary aurora and ionospheric heating experiments (e.g. HAARP). I have investigated the evolution of field-aligned currents in the magnetosphere-ionosphere system and found several notable effects-ion heating due to plasma- neutral friction, electron heating resulting from energetic particle precipitation and ohmic dissipation by strong field-aligned currents. The simulation of plasma. heating in the ionosphere is motivated by a specific auroral event that was simultaneously observed with optical and radar instruments. The results indicate that a consistent explanation of this event requires ohmic heating of electrons in a strong field-aligned electric current layer. They suggest strongly that the observed sequence of events can be explained only if spatial structure is present in the ionosphere so that it requires at least a two-dimensional model. Electron heating in strong field-aligned currents also provides a mechanism to deposit energy in the F-region of ionosphere and thus can explain the formation of tall auroral arcs. The simulation of the formation of field-aligned currents shows a strong plasma density depletion in the region of downward field-aligned current layer. The depletion is due to the divergent flow of the plasma. Similarly, the plasma density increases in the region of upward field- aligned current because of the convergent plasma motion

  9. Pen size and parity effects on maternal behaviour of Small-Tail Han sheep.

    PubMed

    Lv, S-J; Yang, Y; Dwyer, C M; Li, F-K

    2015-07-01

    The aim of this experiment was to study the effects of pen size and parity on maternal behaviour of twin-bearing Small-Tail Han ewes. A total of 24 ewes were allocated to a 2×2 design (six per pen), with parity (primiparous or multiparous) and pen size (large: 6.0×3.0 m; small: 6.0×1.5 m) as main effects at Linyi University, Shandong Province, China. Behaviour was observed from after parturition until weaning. All ewes were observed for 6 h every 5 days from 0700 to1000 h and from 1400 to 1700 h. Continuous focal animal sampling was used to quantify the duration of maternal behaviours: sucking, grooming and following as well as the frequency of udder accepting, udder refusing and low-pitched bleating. Oestradiol and cortisol concentrations in the faeces (collected in the morning every 5 days) were detected using EIA kits. All lambs were weighed 24 h after parturition and again at weaning at 35 days of age. The small pen size significantly reduced following (P<0.005), grooming (P<0.001) and suckling durations (P<0.05), as well as the frequency of udder refusals (P<0.001). However, there was a significant interaction with ewe parity, with decreased grooming and suckling in the small pen largely seen in the multiparous ewes (P<0.001). Independent of pen size, multiparous ewes accepted more sucking attempts by their lambs (P<0.05) and made more low-pitched bleats than primiparous ewes (P<0.001). Multiparous ewes had higher faecal oestradiol concentrations than primiparous ewes (P<0.001), and ewes in small pens had higher faecal cortisol levels compared with ewes in larger pens (P<0.001). As lambs increased in age, the duration of maternal grooming, following and suckling as well as frequency of udder acceptance and low-pitched bleating all declined, and the frequency of udder refusing increased (P<0.001 for all). Ewe parity, but not pen size, affected lamb weight gain during the period of observation (P<0.001). This is the first study to show that pen size

  10. Large- and small-size advantages in sneaking behaviour in the dusky frillgoby Bathygobius fuscus

    NASA Astrophysics Data System (ADS)

    Takegaki, Takeshi; Kaneko, Takashi; Matsumoto, Yukio

    2012-04-01

    Sneaking tactic, a male alternative reproductive tactic involving sperm competition, is generally adopted by small individuals because of its inconspicuousness. However, large size has an advantage when competition occurs between sneakers for fertilization of eggs. Here, we suggest that both large- and small-size advantages of sneaker males are present within the same species. Large sneaker males of the dusky frillgoby Bathygobius fuscus showed a high success rate in intruding into spawning nests because of their advantage in competition among sneaker males in keeping a suitable position to sneak, whereas small sneakers had few chances to sneak. However, small sneaker males were able to stay in the nests longer than large sneaker males when they succeeded in sneak intrusion. This suggests the possibility of an increase in their paternity. The findings of these size-specific behavioural advantages may be important in considering the evolution of size-related reproductive traits.

  11. Ordinary and Extraordinary Movement Behaviour of Small Resident Fish within a Mediterranean Marine Protected Area

    PubMed Central

    Aspillaga, Eneko; Bartumeus, Frederic; Linares, Cristina; Starr, Richard M.; López-Sanz, Àngel; Díaz, David; Zabala, Mikel; Hereu, Bernat

    2016-01-01

    It is important to account for the movement behaviour of fishes when designing effective marine protected areas (MPAs). Fish movements occur across different spatial and temporal scales and understanding the variety of movements is essential to make correct management decisions. This study describes in detail the movement patterns of an economically and commercially important species, Diplodus sargus, within a well-enforced Mediterranean MPA. We monitored horizontal and vertical movements of 41 adult individuals using passive acoustic telemetry for up to one year. We applied novel analysis and visualization techniques to get a comprehensive view of a wide range of movements. D. sargus individuals were highly territorial, moving within small home ranges (< 1 km2), inside which they displayed repetitive diel activity patterns. Extraordinary movements beyond the ordinary home range were observed under two specific conditions. First, during stormy events D. sargus presented a sheltering behaviour, moving to more protected places to avoid the disturbance. Second, during the spawning season they made excursions to deep areas (> 50 m), where they aggregated to spawn. This study advances our understanding about the functioning of an established MPA and provides important insights into the biology and management of a small sedentary species, suggesting the relevance of rare but important fish behaviours. PMID:27437692

  12. 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.

  13. Prison construction and guarding behaviour by European honeybees is dependent on inmate small hive beetle density.

    PubMed

    Ellis, J D; Hepburn, H R; Ellis, A M; Elzen, P J

    2003-08-01

    Increasing small hive beetle (Aethina tumida Murray) density changes prison construction and guarding behaviour in European honeybees (Apis mellifera L.). These changes include more guard bees per imprisoned beetle and the construction of more beetle prisons at the higher beetle density. Despite this, the number of beetles per prison (inmate density) did not change. Beetles solicited food more actively at the higher density and at night. In response, guard bees increased their aggressive behaviour towards beetle prisoners but did not feed beetles more at the higher density. Only 5% of all beetles were found among the combs at the low density but this percentage increased five-fold at the higher one. Successful comb infiltration (and thus reproduction) by beetles is a possible explanation for the significant damage beetles cause to European honeybee colonies in the USA. PMID:12955230

  14. 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.

  15. Predictors of physical activity among rural and small town breast cancer survivors: an application of the theory of planned behaviour.

    PubMed

    Vallance, Jeff K; Lavallee, Celeste; Culos-Reed, Nicole S; Trudeau, Marc G

    2012-01-01

    The primary objective of this study was to investigate the utility of the two-component theory of planned behaviour (TPB) in understanding physical activity intentions and behaviour in rural and small town breast cancer survivors. The secondary objective was to elicit the most common behavioural, normative and control beliefs of rural and small town survivors regarding physical activity. Using a cross-sectional survey design, 524 rural and small town breast cancer survivors completed a mailed survey that assessed physical activity and TPB variables. Physical activity intention explained 12% of the variance in physical activity behaviour (p < 0.01) while the TPB constructs together explained 43% of the variance in physical activity intention (p < 0.01). Unique behavioural, normative and control beliefs were elicited from the sample. The two-component TPB framework appears to be a suitable model to initiate an understanding of physical activity determinants among rural and small town breast cancer survivors. These data can be used in the development and establishment of physical activity behaviour interventions and health promotion materials designed to facilitate physical activity behaviour among rural and small town breast cancer survivors. PMID:22409699

  16. Optimizing information flow in small genetic networks. IV. Spatial coupling

    NASA Astrophysics Data System (ADS)

    Sokolowski, Thomas R.; Tkačik, Gašper

    2015-06-01

    We typically think of cells as responding to external signals independently by regulating their gene expression levels, yet they often locally exchange information and coordinate. Can such spatial coupling be of benefit for conveying signals subject to gene regulatory noise? Here we extend our information-theoretic framework for gene regulation to spatially extended systems. As an example, we consider a lattice of nuclei responding to a concentration field of a transcriptional regulator (the input) by expressing a single diffusible target gene. When input concentrations are low, diffusive coupling markedly improves information transmission; optimal gene activation functions also systematically change. A qualitatively different regulatory strategy emerges where individual cells respond to the input in a nearly steplike fashion that is subsequently averaged out by strong diffusion. While motivated by early patterning events in the Drosophila embryo, our framework is generically applicable to spatially coupled stochastic gene expression models.

  17. Optimizing information flow in small genetic networks. IV. Spatial coupling.

    PubMed

    Sokolowski, Thomas R; Tkačik, Gašper

    2015-06-01

    We typically think of cells as responding to external signals independently by regulating their gene expression levels, yet they often locally exchange information and coordinate. Can such spatial coupling be of benefit for conveying signals subject to gene regulatory noise? Here we extend our information-theoretic framework for gene regulation to spatially extended systems. As an example, we consider a lattice of nuclei responding to a concentration field of a transcriptional regulator (the input) by expressing a single diffusible target gene. When input concentrations are low, diffusive coupling markedly improves information transmission; optimal gene activation functions also systematically change. A qualitatively different regulatory strategy emerges where individual cells respond to the input in a nearly steplike fashion that is subsequently averaged out by strong diffusion. While motivated by early patterning events in the Drosophila embryo, our framework is generically applicable to spatially coupled stochastic gene expression models. PMID:26172739

  18. 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

  19. The asymptotic behaviour of the solution to a system of differential equations with a small parameter and singular initial point

    SciTech Connect

    Il'in, Arlen M; Khachay, Oleg Yu; Leonychev, Yurii A

    2010-02-28

    The initial value problem for a system of nonlinear ordinary differential equations with a small parameter multiplying the highest derivative is investigated. In a neighbourhood of the initial point the asymptotic behaviour of the solution has quite a complicated structure. A uniform asymptotic approximation to the solution up to an arbitrary power of the small parameter is constructed and substantiated. Bibliography: 3 titles.

  20. 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

  1. 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

  2. Effects of emphasising opposition and cooperation on collective movement behaviour during football small-sided games.

    PubMed

    Gonçalves, B; Marcelino, R; Torres-Ronda, L; Torrents, C; Sampaio, J

    2016-07-01

    Optimizing collective behaviour helps to increase performance in mutual tasks. In team sports settings, the small-sided games (SSG) have been used as key context tools to stress out the players' awareness about their in-game required behaviours. Research has mostly described these behaviours when confronting teams have the same number of players, disregarding the frequent situations of low and high inequality. This study compared the players' positioning dynamics when manipulating the number of opponents and teammates during professional and amateur football SSG. The participants played 4v3, 4v5 and 4v7 games, where one team was confronted with low-superiority, low- and high-inferiority situations, and their opponents with low-, medium- and high-cooperation situations. Positional data were used to calculate effective playing space and distances from each player to team centroid, opponent team centroid and nearest opponent. Outcomes suggested that increasing the number of opponents in professional teams resulted in moderate/large decrease in approximate entropy (ApEn) values to both distance to team and opponent team centroid (i.e., the variables present higher regularity/predictability pattern). In low-cooperation game scenarios, the ApEn in amateurs' tactical variables presented a moderate/large increase. The professional teams presented an increase in the distance to nearest opponent with the increase of the cooperation level. Increasing the number of opponents was effective to overemphasise the need to use local information in the positioning decision-making process from professionals. Conversely, amateur still rely on external informational feedback. Increasing the cooperation promoted more regularity in spatial organisation in amateurs and emphasise their players' local perceptions. PMID:26928336

  3. Physiological and behavioural responses of a small heterothermic mammal to fire stimuli.

    PubMed

    Stawski, Clare; Matthews, Jaya K; Körtner, Gerhard; Geiser, Fritz

    2015-11-01

    The predicted increase of the frequency and intensity of wildfires as a result of climate change could have a devastating impact on many species and ecosystems. However, the particular physiological and behavioural adaptions of animals to survive fires are poorly understood. We aimed to provide the first quantitative data on physiological and behavioural mechanisms used by a small heterothermic marsupial mammal, the fat-tailed dunnart (Sminthopsis crassicaudata), that may be crucial for survival during and immediately after a fire. Specifically, we aimed to determine (i) whether captive torpid animals are able to respond to fire stimuli and (ii) which energy saving mechanisms are used in response to fires. The initial response of torpid dunnarts to smoke exposure was to arouse immediately and therefore express shorter and shallower torpor bouts. Dunnarts also increased activity after smoke exposure when food was provided, but not when food was withheld. A charcoal/ash substrate, imitating post-fire conditions, resulted in a decrease in torpor use and activity, but only when food was available. Our novel data suggests that heterothermic mammals are able to respond to fire stimuli, such as smoke, to arouse from torpor as an initial response to fire and adjust torpor use and activity levels according to food availability modulated by fire cues. PMID:26343772

  4. 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

  5. Energy conserving coupling through small apertures in an infinite perfect conducting screen

    NASA Astrophysics Data System (ADS)

    Petzold, J.; Tkachenko, S.; Vick, R.

    2015-11-01

    Apertures in shielding enclosures are an important issue for determining shielding efficiencies. Various mathematical procedures and theories were employed to describe the coupling between the regions connected via an aperture in a well conducting plane. Bethe's theory describes the coupling via the equivalent problem of field excited dipole moments at the location of the aperture. This approach neglects the reaction of the dipole moments on the exciting field and therefore violates energy conservation. This work emphasizes an analytical approach for coupling between half-spaces through small apertures, inspired by the so called method of small antenna, which allows an understandable generalization of Bethe's theory.

  6. 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

  7. 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

  8. Why small males have big sperm: dimorphic squid sperm linked to alternative mating behaviours

    PubMed Central

    2011-01-01

    Background Sperm cells are the target of strong sexual selection that may drive changes in sperm structure and function to maximize fertilisation success. Sperm evolution is regarded to be one of the major consequences of sperm competition in polyandrous species, however it can also be driven by adaptation to the environmental conditions at the site of fertilization. Strong stabilizing selection limits intra-specific variation, and therefore polymorphism, among fertile sperm (eusperm). Here we analyzed reproductive morphology differences among males employing characteristic alternative mating behaviours, and so potentially different conditions of sperm competition and fertilization environment, in the squid Loligo bleekeri. Results Large consort males transfer smaller (average total length = 73 μm) sperm to a female's internal sperm storage location, inside the oviduct; whereas small sneaker males transfer larger (99 μm) sperm to an external location around the seminal receptacle near the mouth. No significant difference in swimming speed was observed between consort and sneaker sperm. Furthermore, sperm precedence in the seminal receptacle was not biased toward longer sperm, suggesting no evidence for large sperm being favoured in competition for space in the sperm storage organ among sneaker males. Conclusions Here we report the first case, in the squid Loligo bleekeri, where distinctly dimorphic eusperm are produced by different sized males that employ alternative mating behaviours. Our results found no evidence that the distinct sperm dimorphism was driven by between- and within-tactic sperm competition. We propose that presence of alternative fertilization environments with distinct characteristics (i.e. internal or external), whether or not in combination with the effects of sperm competition, can drive the disruptive evolution of sperm size. PMID:21831296

  9. Small Body Size at Birth and Behavioural Symptoms of ADHD in Children Aged Five to Six Years

    ERIC Educational Resources Information Center

    Lahti, J.; Raikkonen, K.; Kajantie, E.; Heinonen, K.; Pesonen, A.-K.; Jarvenpaa, A.-L.; Strandberg, T.

    2006-01-01

    Background: Behavioural disorders with a neurodevelopmental background, such as attention deficit hyperactivity disorder (ADHD), have been associated with a non-optimal foetal environment, reflected in small body size at birth. However, the evidence stems from highly selected groups with birth outcomes biased towards the extreme low end of the…

  10. Effects of small particle numbers on long-term behaviour in discrete biochemical systems

    PubMed Central

    Ibrahim, Bashar; Dittrich, Peter

    2014-01-01

    Motivation: The functioning of many biological processes depends on the appearance of only a small number of a single molecular species. Additionally, the observation of molecular crowding leads to the insight that even a high number of copies of species do not guarantee their interaction. How single particles contribute to stabilizing biological systems is not well understood yet. Hence, we aim at determining the influence of single molecules on the long-term behaviour of biological systems, i.e. whether they can reach a steady state. Results: We provide theoretical considerations and a tool to analyse Systems Biology Markup Language models for the possibility to stabilize because of the described effects. The theory is an extension of chemical organization theory, which we called discrete chemical organization theory. Furthermore we scanned the BioModels Database for the occurrence of discrete chemical organizations. To exemplify our method, we describe an application to the Template model of the mitotic spindle assembly checkpoint mechanism. Availability and implementation: http://www.biosys.uni-jena.de/Services.html. Contact: bashar.ibrahim@uni-jena.de or dittrich@minet.uni-jena.de Supplementary information: Supplementary data are available at Bioinformatics online. PMID:25161236

  11. 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

  12. H+-coupled nutrient, micronutrient and drug transporters in the mammalian small intestine.

    PubMed

    Thwaites, David T; Anderson, Catriona M H

    2007-07-01

    The H(+)-electrochemical gradient was originally considered as a driving force for solute transport only across cellular membranes of bacteria, plants and yeast. However, in the mammalian small intestine, a H(+)-electrochemical gradient is present at the epithelial brush-border membrane in the form of an acid microclimate. Over recent years, a large number of H(+)-coupled cotransport mechanisms have been identified at the luminal membrane of the mammalian small intestine. These transporters are responsible for the initial stage in absorption of a remarkable variety of essential and non-essential nutrients and micronutrients, including protein digestion products (di/tripeptides and amino acids), vitamins, short-chain fatty acids and divalent metal ions. Proton-coupled cotransporters expressed at the mammalian small intestinal brush-border membrane include: the di/tripeptide transporter PepT1 (SLC15A1); the proton-coupled amino-acid transporter PAT1 (SLC36A1); the divalent metal transporter DMT1 (SLC11A2); the organic anion transporting polypeptide OATP2B1 (SLC02B1); the monocarboxylate transporter MCT1 (SLC16A1); the proton-coupled folate transporter PCFT (SLC46A1); the sodium-glucose linked cotransporter SGLT1 (SLC5A1); and the excitatory amino acid carrier EAAC1 (SLC1A1). Emerging research demonstrates that the optimal intestinal absorptive capacity of certain H(+)-coupled cotransporters (PepT1 and PAT1) is dependent upon function of the brush-border Na(+)-H(+) exchanger NHE3 (SLC9A3). The high oral bioavailability of a large number of pharmaceutical compounds results, in part, from absorptive transport via the same H(+)-coupled cotransporters. Drugs undergoing H(+)-coupled cotransport across the intestinal brush-border membrane include those used to treat bacterial infections, hypercholesterolaemia, hypertension, hyperglycaemia, viral infections, allergies, epilepsy, schizophrenia, rheumatoid arthritis and cancer. PMID:17468205

  13. H+-coupled nutrient, micronutrient and drug transporters in the mammalian small intestine

    PubMed Central

    Thwaites, David T.; Anderson, Catriona M.H.

    2009-01-01

    The H+-electrochemical gradient was originally considered as a driving force for solute transport only across cellular membranes of bacteria, plants and yeast. However, in the mammalian small intestine a H+electrochemical gradient is present at the epithelial brush-border membrane in the form of an acid microclimate. Over recent years a large number of H+-coupled cotransport mechanisms have been identified at the luminal membrane of the mammalian small intestine. These transporters are responsible for the initial stage in absorption of a remarkable variety of essential and non-essential nutrients and micronutrients including protein digestion products (di/tripeptides and amino acids), vitamins, short-chain fatty acids and divalent metal ions. Proton-coupled cotransporters expressed at the mammalian small intestinal brush-border membrane include: the di/tripeptide transporter PepT1 (SLC15A1); the proton-coupled amino-acid transporter PAT1 (SLC36A1); the divalent metal transporter DMT1 (SLC11A2); the organic anion transporting polypeptide OATP2B1 (SLC02B1); the monocarboxylate transporter MCT1 (SLC16A1); the proton-coupled folate transporter PCFT (SLC46A1); the sodium-glucose linked cotransporter SGLT1 (SLC5A1); and the excitatory amino acid carrier EAAC1 (SLC1A1). Emerging research demonstrates that the optimal intestinal absorptive capacity of certain H+-coupled cotransporters (PepT1 and PAT1) is dependent upon function of the brush-border Na+/H+ exchanger NHE3 (SLC9A3). The high oral bioavailability of a large number of pharmaceutical compounds is due, in part, to absorptive transport via these same H+-coupled cotransporters. Drugs undergoing H+-coupled cotransport across the intestinal brush-border membrane include those used to treat bacterial infections, hypercholesterolaemia, hypertension, hyperglycaemia, viral infections, allergies, epilepsy, schizophrenia, rheumatoid arthritis and cancer. PMID:17468205

  14. 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

  15. Coupled orbit-attitude dynamics and relative state estimation of spacecraft near small Solar System bodies

    NASA Astrophysics Data System (ADS)

    Misra, Gaurav; Izadi, Maziar; Sanyal, Amit; Scheeres, Daniel

    2016-04-01

    The effects of dynamical coupling between the rotational (attitude) and translational (orbital) motion of spacecraft near small Solar System bodies is investigated. This coupling arises due to the weak gravity of these bodies, as well as solar radiation pressure. The traditional approach assumes a point-mass spacecraft model to describe the translational motion of the spacecraft, while the attitude motion is considered to be completely decoupled from the translational motion. The model used here to describe the rigid-body spacecraft dynamics includes the non-uniform rotating gravity field of the small body up to second degree and order along with the attitude dependent terms, solar tide, and solar radiation pressure. This model shows that the second degree and order gravity terms due to the small body affect the dynamics of the spacecraft to the same extent as the orbit-attitude coupling due to the primary gravity (zeroth order) term. Variational integrators are used to simulate the dynamics of both the rigid spacecraft and the point mass. The small bodies considered here are modeled after Near-Earth Objects (NEO) 101955 Bennu, and 25143 Itokawa, and are assumed to be triaxial ellipsoids with uniform density. Differences in the numerically obtained trajectories of a rigid spacecraft and a point mass are then compared, to illustrate the impact of the orbit-attitude coupling on spacecraft dynamics in proximity of small bodies. Possible implications on the performance of model-based spacecraft control and on the station-keeping budget, if the orbit-attitude coupling is not accounted for in the model of the dynamics, are also discussed. An almost globally asymptotically stable motion estimation scheme based solely on visual/optical feedback that estimates the relative motion of the asteroid with respect to the spacecraft is also obtained. This estimation scheme does not require a model of the dynamics of the asteroid, which makes it perfectly suited for asteroids whose

  16. 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.

  17. Development of very small-diameter, inductively coupled magnetized plasma device.

    PubMed

    Kuwahara, D; Mishio, A; Nakagawa, T; Shinohara, S

    2013-10-01

    In order to miniaturize a high-density, inductively coupled magnetized plasma or helicon plasma to be applied to, e.g., an industrial application and an electric propulsion field, small helicon device has been developed. The specifications of this device along with the experimental results are described. We have succeeded in generating high-density (~10(19) m(-3)) plasmas using quartz tubes with very small diameters of 10 and 20 mm, with a radio frequency power ~1200 and 700 W, respectively, in the presence of the magnetic field less than 1 kG. PMID:24182105

  18. 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

  19. 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.

  20. Teachers' and Students' Verbal Behaviours during Cooperative and Small-Group Learning

    ERIC Educational Resources Information Center

    Gillies, Robyn M.

    2006-01-01

    Background: Teachers play a critical role in promoting interactions between students and engaging them in the learning process. This study builds on a study by Hertz-Lazarowitz and Shachar (1990) who found that during cooperative learning teachers' verbal behaviours were more helpful to and encouraging of their students' efforts while during…

  1. 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

  2. Small Worlds, Lifeworlds, and Information: The Ramifications of the Information Behaviour of Social Groups in Public Policy and the Public Sphere

    ERIC Educational Resources Information Center

    Burnett, Gary; Jaeger, Paul T.

    2008-01-01

    Introduction: This paper attempts to build bridges between two sets of theoretical concepts related to information behaviour: the macro-level concepts of Jurgen Habermas related to lifeworlds and the micro-level concepts of Elfreda Chatman related to small worlds. Argument: Habermas and Chatman explored similar issues of information behaviour at…

  3. Whole ecosystem approaches for assessing the coupling of N and P cycles in small streams

    NASA Astrophysics Data System (ADS)

    Schade, J. D.; Thomas, S. A.; Seybold, E. C.; Drake, T.; Lewis, K.; MacNeill, K.; Zimov, N.

    2010-12-01

    The most pressing environmental problems faced by society are manifestations of changes in biogeochemical cycles. The urgency of mitigating these problems has brought into sharp focus the need for a stronger mechanistic understanding of the factors that control biogeochemical cycles and how these factors affect multiple elements. Our overarching goal is to assess the strength of coupling between carbon, nitrogen, and phosphorus cycles in small headwater streams, including streams draining small watersheds in Northern California and the East Siberian Arctic. We have used a range of whole ecosystem approaches, rooted in nutrient spiraling theory, including plateau and pulsed nutrient enrichment experiments at a range of N:P ratios in heterotrophic and autotrophic streams. We use these experiments to calculate changes in nutrient spiraling metrics in response to changes in absolute and relative supply of N and P, and we use these results to infer the strength of the linkage between N and P cycles. In all California study streams, ecological processes are N limited, and we have observed significant changes in the strength of N and P coupling depending on position along the stream network. In small heterotrophic streams, addition of N caused significant increases in P uptake, while P had little influence on N. In larger autotrophic streams, N and P were only weakly coupled, which we attributed to a shift towards dominance of uptake by algae rather than heterotrophic bacteria, which is associated with differences in cellular structures. In addition, we have observed a small but consistent reduction in P uptake at high N:P of supply in autotrophic streams, which we speculate may indicate a suppression of N fixers at high N supply. In the Arctic, we have observed less consistency in the response of streams to nutrient enrichment, with some streams showing very little change in N or P uptake with changes in supply N:P, and others showing a decrease in N uptake in response

  4. Ultra-small single-negative electric metamaterials for electromagnetic coupling reduction of microstrip antenna array.

    PubMed

    Xu, He-Xiu; Wang, Guang-Ming; Qi, Mei-Qing; Zeng, Hui-Yong

    2012-09-24

    We report initially the design, fabrication and measurement of using waveguided electric metamaterials (MTM) in the design of closely-spaced microtrip antenna arrays with mutual coupling reduction. The complementary spiral ring resonators (CSRs) which exhibit single negative resonant permittivity around 3.5GHz are used as the basic electric MTM element. For verification, two CSRs with two and three concentric rings are considered, respectively. By properly arranging these well engineered waveguided MTMs between two H-plane coupled patch antennas, both numerical and measured results indicate that more than 8.4 dB mutual coupling reduction is obtained. The mechanism has been studied from a physical insight. The electric MTM element is electrically small, enabling the resultant antenna array to exhibit a small separation (λo/8 at the operating wavelength) and thus a high directivity. The proposed strategy opens an avenue to new types of antenna with super performances and can be generalized for other electric resonators. PMID:23037347

  5. Experiments on the magnetic coupling in a small scale counter rotating marine current turbine

    NASA Astrophysics Data System (ADS)

    Kim, I. C.; Lee, N. J.; Wata, J.; Hyun, B. S.; Lee, Y. H.

    2016-05-01

    Modern economies are dependent on energy consumption to ensure growth or sustainable development. Renewable energy sources provide a source of energy that can provide energy security and is renewable. Tidal energy is more predictable than other sources or renewable energy like the sun or wind. Horizontal axis marine current turbines are currently the most advanced and commercially feasible option for tidal current convertors. A dual rotor turbine is theoretically able to produce more power than a single rotor turbine at the same fluid velocity. Previous experiments for a counter rotating dual rotor horizontal axis marine current turbine used a mechanical oil seal coupling that caused mechanical losses when water entered through small gaps at the shaft. A new magnetic coupling assembly eliminates the need for a shaft to connect physically with the internal mechanisms and is water tight. This reduces mechanical losses in the system and the effect on the dual rotor performance is presented in this paper.

  6. 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

  7. 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

  8. Small cages with insect couples provide a simple method for a preliminary assessment of mating disruption.

    PubMed

    Briand, Françoise; Guerin, Patrick M; Charmillot, Pierre-Joseph; Kehrli, Patrik

    2012-01-01

    Mating disruption by sex pheromones is a sustainable, effective and widely used pest management scheme. A drawback of this technique is its challenging assessment of effectiveness in the field (e.g., spatial scale, pest density). The aim of this work was to facilitate the evaluation of field-deployed pheromone dispensers. We tested the suitability of small insect field cages for a pre-evaluation of the impact of sex pheromones on mating using the grape moths Eupoecilia ambiguella and Lobesia botrana, two major pests in vineyards. Cages consisted of a cubic metal frame of 35 cm sides, which was covered with a mosquito net of 1500 μm mesh size. Cages were installed in the centre of pheromone-treated and untreated vineyards. In several trials, 1 to 20 couples of grape moths per cage were released for one to three nights. The proportion of mated females was between 15 to 70% lower in pheromone-treated compared to untreated vineyards. Overall, the exposure of eight couples for one night was adequate for comparing different control schemes. Small cages may therefore provide a fast and cheap method to compare the effectiveness of pheromone dispensers under standardised semi-field conditions and may help predict the value of setting-up large-scale field trials. PMID:22645483

  9. Technique for Extension of Small Antenna Array Mutual-Coupling Data to Larger Antenna Arrays

    NASA Technical Reports Server (NTRS)

    Bailey, M. C.

    1996-01-01

    A technique is presented whereby the mutual interaction between a small number of elements in a planar array can be interpolated and extrapolated to accurately predict the combined interactions in a much larger array of many elements. An approximate series expression is developed, based upon knowledge of the analytical characteristic behavior of the mutual admittance between small aperture antenna elements in a conducting ground plane. This expression is utilized to analytically extend known values for a few spacings and orientations to other element configurations, thus eliminating the need to numerically integrate a large number of highly oscillating and slowly converging functions. This paper shows that the technique can predict very accurately the mutual coupling between elements in a very large planar array with a knowledge of the self-admittance of an isolated element and the coupling between only two-elements arranged in eight different pair combinations. These eight pair combinations do not necessarily have to correspond to pairs in the large array, although all of the individual elements must be identical.

  10. Small Cages with Insect Couples Provide a Simple Method for a Preliminary Assessment of Mating Disruption

    PubMed Central

    Briand, Françoise; Guerin, Patrick M.; Charmillot, Pierre-Joseph; Kehrli, Patrik

    2012-01-01

    Mating disruption by sex pheromones is a sustainable, effective and widely used pest management scheme. A drawback of this technique is its challenging assessment of effectiveness in the field (e.g., spatial scale, pest density). The aim of this work was to facilitate the evaluation of field-deployed pheromone dispensers. We tested the suitability of small insect field cages for a pre-evaluation of the impact of sex pheromones on mating using the grape moths Eupoecilia ambiguella and Lobesia botrana, two major pests in vineyards. Cages consisted of a cubic metal frame of 35 cm sides, which was covered with a mosquito net of 1500 μm mesh size. Cages were installed in the centre of pheromone-treated and untreated vineyards. In several trials, 1 to 20 couples of grape moths per cage were released for one to three nights. The proportion of mated females was between 15 to 70% lower in pheromone-treated compared to untreated vineyards. Overall, the exposure of eight couples for one night was adequate for comparing different control schemes. Small cages may therefore provide a fast and cheap method to compare the effectiveness of pheromone dispensers under standardised semi-field conditions and may help predict the value of setting-up large-scale field trials. PMID:22645483

  11. Molecular Evidence for Gender Differences in the Migratory Behaviour of a Small Seabird

    PubMed Central

    Medeiros, Renata J.; King, R. Andrew; Symondson, William O. C.; Cadiou, Bernard; Zonfrillo, Bernard; Bolton, Mark; Morton, Rab; Howell, Stephen; Clinton, Anthony; Felgueiras, Marcial; Thomas, Robert J.

    2012-01-01

    Molecular sexing revealed an unexpectedly strong female bias in the sex ratio of pre-breeding European Storm Petrels (Hydrobates pelagicus), attracted to playback of conspecific calls during their northwards migration past SW Europe. This bias was consistent across seven years, ranging from 80.8% to 89.7% female (mean annual sex ratio ± SD = 85.5% female ±4.1%). The sex ratio did not differ significantly from unity (i.e., 50% female) among (i) Storm Petrel chicks at a breeding colony in NW France, (ii) adults found dead on beaches in Southern Portugal, (iii) breeding birds attending nest burrows in the UK, captured by hand, and (iv) adults captured near a breeding colony in the UK using copies of the same sound recordings as used in Southern Europe, indicating that females are not inherently more strongly attracted to playback calls than males. A morphological discriminant function analysis failed to provide a good separation of the sexes, showing the importance of molecular sexing for this species. We found no sex difference in the seasonal or nocturnal timing of migration past Southern Europe, but there was a significant tendency for birds to be caught in sex-specific aggregations. The preponderance of females captured in Southern Europe suggests that the sexes may differ in migration route or in their colony-prospecting behaviour during migration, at sites far away from their natal colonies. Such differences in migration behaviour between males and females are poorly understood but have implications for the vulnerability of seabirds to pollution and environmental change at sea during the non-breeding season. PMID:23029481

  12. Molecular evidence for gender differences in the migratory behaviour of a small seabird.

    PubMed

    Medeiros, Renata J; King, R Andrew; Symondson, William O C; Cadiou, Bernard; Zonfrillo, Bernard; Bolton, Mark; Morton, Rab; Howell, Stephen; Clinton, Anthony; Felgueiras, Marcial; Thomas, Robert J

    2012-01-01

    Molecular sexing revealed an unexpectedly strong female bias in the sex ratio of pre-breeding European Storm Petrels (Hydrobates pelagicus), attracted to playback of conspecific calls during their northwards migration past SW Europe. This bias was consistent across seven years, ranging from 80.8% to 89.7% female (mean annual sex ratio ± SD = 85.5% female ±4.1%). The sex ratio did not differ significantly from unity (i.e., 50% female) among (i) Storm Petrel chicks at a breeding colony in NW France, (ii) adults found dead on beaches in Southern Portugal, (iii) breeding birds attending nest burrows in the UK, captured by hand, and (iv) adults captured near a breeding colony in the UK using copies of the same sound recordings as used in Southern Europe, indicating that females are not inherently more strongly attracted to playback calls than males. A morphological discriminant function analysis failed to provide a good separation of the sexes, showing the importance of molecular sexing for this species. We found no sex difference in the seasonal or nocturnal timing of migration past Southern Europe, but there was a significant tendency for birds to be caught in sex-specific aggregations. The preponderance of females captured in Southern Europe suggests that the sexes may differ in migration route or in their colony-prospecting behaviour during migration, at sites far away from their natal colonies. Such differences in migration behaviour between males and females are poorly understood but have implications for the vulnerability of seabirds to pollution and environmental change at sea during the non-breeding season. PMID:23029481

  13. Small-area fiber-coupled scintillation camera for imaging beta-ray distributions intraoperatively

    NASA Astrophysics Data System (ADS)

    MacDonald, L. R.; Tornai, Martin P.; Levin, C. S.; Park, J.; Atac, Muzaffer; Cline, David B.; Hoffman, Eric G.

    1995-09-01

    A small area, imaging, scintillation probe is being developed for locating small amounts of radio-labeled malignant tissue during surgery. Preliminary in brain surgery, avoiding the removal of excess tissue is a priority. It is possible to locate the main body of a brain tumor both before and during surgery, but once the bulk of the tumor is excised the identification of residual malignant tissue is difficult. A probe that covers an area of 1-2 cm(superscript 2) with an intrinsic resolution of 1-2 mm could locate small tumor masses that pose a threat of recurrence of the disease, and prevent removal of healthy tissue. A pre-operative injection of tumor seeking, beta emitting radiopharmaceutical (e.g. (superscript 18)fluorodeoxyuridine-FDUR-) will label the tumor. The limited range of beta-rays ensures proximity upon successful detection. Plastic scintillators are used for beta detection, and visible light photon counters (VLPCs) detect the scintillation light. For maneuverability in and around the surgical cavity, the scintillators are coupled to the VLPCs via 2 m of optical fiber. An imaging device can cover the tissue bed in a time compatible with surgery, as opposed to a single element detector on the order of 1-2 mm in size with comparable resolution. An imager also distinguishes high background rates (such as from annihilation gammas in FDUR) and concentrations of activity.

  14. Time dependent quantum thermodynamics of a coupled quantum oscillator system in a small thermal environment

    SciTech Connect

    Barnes, George L.; Kellman, Michael E.

    2013-12-07

    Simulations are performed of a small quantum system interacting with a quantum environment. The system consists of various initial states of two harmonic oscillators coupled to give normal modes. The environment is “designed” by its level pattern to have a thermodynamic temperature. A random coupling causes the system and environment to become entangled in the course of time evolution. The approach to a Boltzmann distribution is observed, and effective fitted temperatures close to the designed temperature are obtained. All initial pure states of the system are driven to equilibrium at very similar rates, with quick loss of memory of the initial state. The time evolution of the von Neumann entropy is calculated as a measure of equilibration and of quantum coherence. It is pointed out using spatial density distribution plots that quantum interference is eliminated only with maximal entropy, which corresponds thermally to infinite temperature. Implications of our results for the notion of “classicalizing” behavior in the approach to thermal equilibrium are briefly considered.

  15. Time dependent quantum thermodynamics of a coupled quantum oscillator system in a small thermal environment.

    PubMed

    Barnes, George L; Kellman, Michael E

    2013-12-01

    Simulations are performed of a small quantum system interacting with a quantum environment. The system consists of various initial states of two harmonic oscillators coupled to give normal modes. The environment is "designed" by its level pattern to have a thermodynamic temperature. A random coupling causes the system and environment to become entangled in the course of time evolution. The approach to a Boltzmann distribution is observed, and effective fitted temperatures close to the designed temperature are obtained. All initial pure states of the system are driven to equilibrium at very similar rates, with quick loss of memory of the initial state. The time evolution of the von Neumann entropy is calculated as a measure of equilibration and of quantum coherence. It is pointed out using spatial density distribution plots that quantum interference is eliminated only with maximal entropy, which corresponds thermally to infinite temperature. Implications of our results for the notion of "classicalizing" behavior in the approach to thermal equilibrium are briefly considered. PMID:24320365

  16. Closed set of the uniqueness conditions and bifurcation criteria in generalized coupled thermoplasticity for small deformations

    NASA Astrophysics Data System (ADS)

    Śloderbach, Zdzisław

    2016-04-01

    This paper reports the results of a study into global and local conditions of uniqueness and the criteria excluding the possibility of bifurcation of the equilibrium state for small strains. The conditions and criteria are derived on the basis of an analysis of the problem of uniqueness of a solution involving the basic incremental boundary problem of coupled generalized thermo-elasto-plasticity. This work forms a follow-up of previous research (Śloderbach in Bifurcations criteria for equilibrium states in generalized thermoplasticity, IFTR Reports, 1980, Arch Mech 3(35):337-349, 351-367, 1983), but contains a new derivation of global and local criteria excluding a possibility of bifurcation of an equilibrium state regarding a comparison body dependent on the admissible fields of stress rate. The thermal elasto-plastic coupling effects, non-associated laws of plastic flow and influence of plastic strains on thermoplastic properties of a body were taken into account in this work. Thus, the mathematical problem considered here is not a self-conjugated problem.

  17. Aerodynamic Modeling of Transonic Aircraft Using Vortex Lattice Coupled with Transonic Small Disturbance for Conceptual Design

    NASA Technical Reports Server (NTRS)

    Chaparro, Daniel; Fujiwara, Gustavo E. C.; Ting, Eric; Nguyen, Nhan

    2016-01-01

    The need to rapidly scan large design spaces during conceptual design calls for computationally inexpensive tools such as the vortex lattice method (VLM). Although some VLM tools, such as Vorview have been extended to model fully-supersonic flow, VLM solutions are typically limited to inviscid, subcritical flow regimes. Many transport aircraft operate at transonic speeds, which limits the applicability of VLM for such applications. This paper presents a novel approach to correct three-dimensional VLM through coupling of two-dimensional transonic small disturbance (TSD) solutions along the span of an aircraft wing in order to accurately predict transonic aerodynamic loading and wave drag for transport aircraft. The approach is extended to predict flow separation and capture the attenuation of aerodynamic forces due to boundary layer viscosity by coupling the TSD solver with an integral boundary layer (IBL) model. The modeling framework is applied to the NASA General Transport Model (GTM) integrated with a novel control surface known as the Variable Camber Continuous Trailing Edge Flap (VCCTEF).

  18. Closed set of the uniqueness conditions and bifurcation criteria in generalized coupled thermoplasticity for small deformations

    NASA Astrophysics Data System (ADS)

    Śloderbach, Zdzisław

    2016-05-01

    This paper reports the results of a study into global and local conditions of uniqueness and the criteria excluding the possibility of bifurcation of the equilibrium state for small strains. The conditions and criteria are derived on the basis of an analysis of the problem of uniqueness of a solution involving the basic incremental boundary problem of coupled generalized thermo-elasto-plasticity. This work forms a follow-up of previous research (Śloderbach in Bifurcations criteria for equilibrium states in generalized thermoplasticity, IFTR Reports, 1980, Arch Mech 3(35):337-349, 351-367, 1983), but contains a new derivation of global and local criteria excluding a possibility of bifurcation of an equilibrium state regarding a comparison body dependent on the admissible fields of stress rate. The thermal elasto-plastic coupling effects, non-associated laws of plastic flow and influence of plastic strains on thermoplastic properties of a body were taken into account in this work. Thus, the mathematical problem considered here is not a self-conjugated problem.

  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. Optimal Gradient Estimates and Asymptotic Behaviour for the Vlasov-Poisson System with Small Initial Data

    NASA Astrophysics Data System (ADS)

    Hwang, Hyung Ju; Rendall, Alan D.; Velázquez, Juan J. L.

    2011-04-01

    The Vlasov-Poisson system describes interacting systems of collisionless particles. For solutions with small initial data in three dimensions it is known that the spatial density of particles decays as t -3 at late times. In this paper this statement is refined to show that each derivative of the density which is taken leads to an extra power of decay, so that in N dimensions for {N ≥q 3} the derivative of the density of order k decays as t - N- k . An asymptotic formula for the solution at late times is also obtained.

  1. Heterogeneity and nearest-neighbor coupling can explain small-worldness and wave properties in pancreatic islets

    NASA Astrophysics Data System (ADS)

    Cappon, Giacomo; Pedersen, Morten Gram

    2016-05-01

    Many multicellular systems consist of coupled cells that work as a syncytium. The pancreatic islet of Langerhans is a well-studied example of such a microorgan. The islets are responsible for secretion of glucose-regulating hormones, mainly glucagon and insulin, which are released in distinct pulses. In order to observe pulsatile insulin secretion from the β-cells within the islets, the cellular responses must be synchronized. It is now well established that gap junctions provide the electrical nearest-neighbor coupling that allows excitation waves to spread across islets to synchronize the β-cell population. Surprisingly, functional coupling analysis of calcium responses in β-cells shows small-world properties, i.e., a high degree of local coupling with a few long-range "short-cut" connections that reduce the average path-length greatly. Here, we investigate how such long-range functional coupling can appear as a result of heterogeneity, nearest-neighbor coupling, and wave propagation. Heterogeneity is also able to explain a set of experimentally observed synchronization and wave properties without introducing all-or-none cell coupling and percolation theory. Our theoretical results highlight how local biological coupling can give rise to functional small-world properties via heterogeneity and wave propagation.

  2. Heterogeneity and nearest-neighbor coupling can explain small-worldness and wave properties in pancreatic islets.

    PubMed

    Cappon, Giacomo; Pedersen, Morten Gram

    2016-05-01

    Many multicellular systems consist of coupled cells that work as a syncytium. The pancreatic islet of Langerhans is a well-studied example of such a microorgan. The islets are responsible for secretion of glucose-regulating hormones, mainly glucagon and insulin, which are released in distinct pulses. In order to observe pulsatile insulin secretion from the β-cells within the islets, the cellular responses must be synchronized. It is now well established that gap junctions provide the electrical nearest-neighbor coupling that allows excitation waves to spread across islets to synchronize the β-cell population. Surprisingly, functional coupling analysis of calcium responses in β-cells shows small-world properties, i.e., a high degree of local coupling with a few long-range "short-cut" connections that reduce the average path-length greatly. Here, we investigate how such long-range functional coupling can appear as a result of heterogeneity, nearest-neighbor coupling, and wave propagation. Heterogeneity is also able to explain a set of experimentally observed synchronization and wave properties without introducing all-or-none cell coupling and percolation theory. Our theoretical results highlight how local biological coupling can give rise to functional small-world properties via heterogeneity and wave propagation. PMID:27249943

  3. Breakdown of Bragg-Gray behaviour for low-density detectors under electronic disequilibrium conditions in small megavoltage photon fields.

    PubMed

    Kumar, Sudhir; Fenwick, John D; Underwood, Tracy S A; Deshpande, Deepak D; Scott, Alison J D; Nahum, Alan E

    2015-10-21

    In small photon fields ionisation chambers can exhibit large deviations from Bragg-Gray behaviour; the EGSnrc Monte Carlo (MC) code system has been employed to investigate this 'Bragg-Gray breakdown'. The total electron (+positron) fluence in small water and air cavities in a water phantom has been computed for a full linac beam model as well as for a point source spectrum for 6 MV and 15 MV qualities for field sizes from 0.25  ×  0.25 cm(2) to 10  ×  10 cm(2). A water-to-air perturbation factor has been derived as the ratio of total electron (+positron) fluence, integrated over all energies, in a tiny water volume to that in a 'PinPoint 3D-chamber-like' air cavity; for the 0.25  ×  0.25 cm(2) field size the perturbation factors are 1.323 and 2.139 for 6 MV and 15 MV full linac geometries respectively. For the 15 MV full linac geometry for field sizes of 1  ×  1 cm(2) and smaller not only the absolute magnitude but also the 'shape' of the total electron fluence spectrum in the air cavity is significantly different to that in the water 'cavity'. The physics of this 'Bragg-Gray breakdown' is fully explained, making reference to the Fano theorem. For the 15 MV full linac geometry in the 0.25  ×  0.25 cm(2) field the directly computed MC dose ratio, water-to-air, differs by 5% from the product of the Spencer-Attix stopping-power ratio (SPR) and the perturbation factor; this 'difference' is explained by the difference in the shapes of the fluence spectra and is also formulated theoretically. We show that the dimensions of an air-cavity with a perturbation factor within 5% of unity would have to be impractically small in these highly non-equilibrium photon fields. In contrast the dose to water in a 0.25  ×  0.25 cm(2) field derived by multiplying the dose in the single-crystal diamond dosimeter (SCDDo) by the Spencer-Attix ratio is within 2.9% of the dose computed directly in the water voxel for full linac

  4. Study on small-strain behaviours of methane hydrate sandy sediments using discrete element method

    SciTech Connect

    Yu Yanxin; Cheng Yipik; Xu Xiaomin; Soga, Kenichi

    2013-06-18

    Methane hydrate bearing soil has attracted increasing interest as a potential energy resource where methane gas can be extracted from dissociating hydrate-bearing sediments. Seismic testing techniques have been applied extensively and in various ways, to detect the presence of hydrates, due to the fact that hydrates increase the stiffness of hydrate-bearing sediments. With the recognition of the limitations of laboratory and field tests, wave propagation modelling using Discrete Element Method (DEM) was conducted in this study in order to provide some particle-scale insights on the hydrate-bearing sandy sediment models with pore-filling and cementation hydrate distributions. The relationship between shear wave velocity and hydrate saturation was established by both DEM simulations and analytical solutions. Obvious differences were observed in the dependence of wave velocity on hydrate saturation for these two cases. From the shear wave velocity measurement and particle-scale analysis, it was found that the small-strain mechanical properties of hydrate-bearing sandy sediments are governed by both the hydrate distribution patterns and hydrate saturation.

  5. The asymptotic behaviour of parton distributions at small and large x

    NASA Astrophysics Data System (ADS)

    Ball, Richard D.; Nocera, Emanuele R.; Rojo, Juan

    2016-07-01

    It has been argued from the earliest days of quantum chromodynamics that at asymptotically small values of x the parton distribution functions (PDFs) of the proton behave as x^α , where the values of α can be deduced from Regge theory, while at asymptotically large values of x the PDFs behave as (1-x)^β , where the values of β can be deduced from the Brodsky-Farrar quark counting rules. We critically examine these claims by extracting the exponents α and β from various global fits of parton distributions, analysing their scale dependence, and comparing their values to the naive expectations. We find that for valence distributions both Regge theory and counting rules are confirmed, at least within uncertainties, while for sea quarks and gluons the results are less conclusive. We also compare results from various PDF fits for the structure function ratio F_2^n/F_2^p at large x, and caution against unrealistic uncertainty estimates due to overconstrained parametrisations.

  6. Hydrological behaviour of a small catchment in the dehesa landuse system (Extremadura, SW Spain)

    NASA Astrophysics Data System (ADS)

    Ceballos, Antonio; Schnabel, Susanne

    1998-09-01

    Investigations of the hydrological processes operating in a small experimental catchment representative of the dehesa ecosystem were carried out. The dehesa constitutes a system of agro-silvo-pastoral landuse, which is characterized by a Mediterranean, semi-arid climate. The study includes an analysis of the relationships between rainfall, soil water content and discharge, as well as the establishment of the annual water budget. The results demonstrate a complex hydrological response. The relationships between the factors involved and the operating processes are difficult to explain because of the decisive role played by the valley bottoms. These areas typically possess a sediment fill, and contrast with the shallow soils developed on the hillslopes. Genesis and quantity of runoff (Hortonian or saturation) measured at the outlet depend on the antecedent moisture conditions of the valley bottoms because of their water-retention capacity. Annual runoff coefficients are similar to those reported from other semi-arid areas. The analysis of the annual water budget shows that rainfall is positively related with both actual evapotranspiration and discharge.

  7. Ensemble Activation of G-Protein -Coupled Receptors Revealed by Small-Angle Neutron Scattering

    NASA Astrophysics Data System (ADS)

    Chu, Xiang-Qiang; Perera, Suchithranga; Shrestha, Utsab; Chawla, Udeep; Struts, Andrey; Qian, Shuo; Brown, Michael

    2014-03-01

    Rhodopsin is a G-protein -coupled receptor (GPCR) involved in visual light perception and occurs naturally in a membrane lipid environment. Rhodopsin photoactivation yields cis-trans isomerization of retinal giving equilibrium between inactive Meta-I and active Meta-II states. Does photoactivation lead to a single Meta-II conformation, or do substates exist as described by an ensemble-activation mechanism (EAM)? We use small-angle neutron scattering (SANS) to investigate conformational changes in rhodopsin-detergent and rhodopsin-lipid complexes upon photoactivation. Meta-I state is stabilized in CHAPS-solubilized rhodopsin, while Meta-II is trapped in DDM-solubilized rhodopsin. SANS data are acquired from 80% D2O solutions and at contrast-matching points for both DDM and CHAPS samples. Our experiments demonstrate that for detergent-solubilized rhodopsin, SANS with contrast variation can detect structural differences between the rhodopsin dark-state, Meta-I, Meta-II, and ligand-free opsin states. Dark-state rhodopsin has more conformational flexibility in DDM micelles compared to CHAPS, which is consistent with an ensemble of activated Meta-II states. Furthermore, time-resolved SANS enables study of the time-dependent structural transitions between Meta-I and Meta-II, which is crucial to understanding the ensemble-based activation.

  8. Enhancing Social Integration of Immigrant Pupils at Risk for Social, Emotional and/or Behavioural Difficulties: The Outcomes of a Small-Scale Social-Emotional Learning Programme

    ERIC Educational Resources Information Center

    Doikou-Avlidou, Maro; Dadatsi, Katerina

    2013-01-01

    The present study aimed to explore the outcomes of a small-scale social and emotional learning (SEL) intervention programme regarding the social behaviour and the social position of pupils from culturally diverse backgrounds. Seven primary and secondary education teachers participated in the study along with the pupils attending their classes;…

  9. 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)

  10. Dihydromunduletone Is a Small-Molecule Selective Adhesion G Protein-Coupled Receptor Antagonist.

    PubMed

    Stoveken, Hannah M; Bahr, Laura L; Anders, M W; Wojtovich, Andrew P; Smrcka, Alan V; Tall, Gregory G

    2016-09-01

    Adhesion G protein-coupled receptors (aGPCRs) have emerging roles in development and tissue maintenance and is the most prevalent GPCR subclass mutated in human cancers, but to date, no drugs have been developed to target them in any disease. aGPCR extracellular domains contain a conserved subdomain that mediates self-cleavage proximal to the start of the 7-transmembrane domain (7TM). The two receptor protomers, extracellular domain and amino terminal fragment (NTF), and the 7TM or C-terminal fragment remain noncovalently bound at the plasma membrane in a low-activity state. We recently demonstrated that NTF dissociation liberates the 7TM N-terminal stalk, which acts as a tethered-peptide agonist permitting receptor-dependent heterotrimeric G protein activation. In many cases, natural aGPCR ligands are extracellular matrix proteins that dissociate the NTF to reveal the tethered agonist. Given the perceived difficulty in modifying extracellular matrix proteins to create aGPCR probes, we developed a serum response element (SRE)-luciferase-based screening approach to identify GPR56/ADGRG1 small-molecule inhibitors. A 2000-compound library comprising known drugs and natural products was screened for GPR56-dependent SRE activation inhibitors that did not inhibit constitutively active Gα13-dependent SRE activation. Dihydromunduletone (DHM), a rotenoid derivative, was validated using cell-free aGPCR/heterotrimeric G protein guanosine 5'-3-O-(thio)triphosphate binding reconstitution assays. DHM inhibited GPR56 and GPR114/ADGRG5, which have similar tethered agonists, but not the aGPCR GPR110/ADGRF1, M3 muscarinic acetylcholine, or β2 adrenergic GPCRs. DHM inhibited tethered peptide agonist-stimulated and synthetic peptide agonist-stimulated GPR56 but did not inhibit basal activity, demonstrating that it antagonizes the peptide agonist. DHM is a novel aGPCR antagonist and potentially useful chemical probe that may be developed as a future aGPCR therapeutic. PMID:27338081

  11. Breakdown of Bragg-Gray behaviour for low-density detectors under electronic disequilibrium conditions in small megavoltage photon fields

    NASA Astrophysics Data System (ADS)

    Kumar, Sudhir; Fenwick, John D.; Underwood, Tracy S. A.; Deshpande, Deepak D.; Scott, Alison J. D.; Nahum, Alan E.

    2015-10-01

    In small photon fields ionisation chambers can exhibit large deviations from Bragg-Gray behaviour; the EGSnrc Monte Carlo (MC) code system has been employed to investigate this ‘Bragg-Gray breakdown’. The total electron (+positron) fluence in small water and air cavities in a water phantom has been computed for a full linac beam model as well as for a point source spectrum for 6 MV and 15 MV qualities for field sizes from 0.25  ×  0.25 cm2 to 10  ×  10 cm2. A water-to-air perturbation factor has been derived as the ratio of total electron (+positron) fluence, integrated over all energies, in a tiny water volume to that in a ‘PinPoint 3D-chamber-like’ air cavity; for the 0.25  ×  0.25 cm2 field size the perturbation factors are 1.323 and 2.139 for 6 MV and 15 MV full linac geometries respectively. For the 15 MV full linac geometry for field sizes of 1  ×  1 cm2 and smaller not only the absolute magnitude but also the ‘shape’ of the total electron fluence spectrum in the air cavity is significantly different to that in the water ‘cavity’. The physics of this ‘Bragg-Gray breakdown’ is fully explained, making reference to the Fano theorem. For the 15 MV full linac geometry in the 0.25  ×  0.25 cm2 field the directly computed MC dose ratio, water-to-air, differs by 5% from the product of the Spencer-Attix stopping-power ratio (SPR) and the perturbation factor; this ‘difference’ is explained by the difference in the shapes of the fluence spectra and is also formulated theoretically. We show that the dimensions of an air-cavity with a perturbation factor within 5% of unity would have to be impractically small in these highly non-equilibrium photon fields. In contrast the dose to water in a 0.25  ×  0.25 cm2 field derived by multiplying the dose in the single-crystal diamond dosimeter (SCDDo) by the Spencer-Attix ratio is within 2.9% of the dose computed directly in the water voxel

  12. 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

  13. SOPPA and CCSD vibrational corrections to NMR indirect spin-spin coupling constants of small hydrocarbons

    SciTech Connect

    Faber, Rasmus; Sauer, Stephan P. A.

    2015-12-31

    We present zero-point vibrational corrections to the indirect nuclear spin-spin coupling constants in ethyne, ethene, cyclopropene and allene. The calculations have been carried out both at the level of the second order polarization propagator approximation (SOPPA) employing a new implementation in the DALTON program, at the density functional theory level with the B3LYP functional employing also the Dalton program and at the level of coupled cluster singles and doubles (CCSD) theory employing the implementation in the CFOUR program. Specialized coupling constant basis sets, aug-cc-pVTZ-J, have been employed in the calculations. We find that on average the SOPPA results for both the equilibrium geometry values and the zero-point vibrational corrections are in better agreement with the CCSD results than the corresponding B3LYP results. Furthermore we observed that the vibrational corrections are in the order of 5 Hz for the one-bond carbon-hydrogen couplings and about 1 Hz or smaller for the other couplings apart from the one-bond carbon-carbon coupling (11 Hz) and the two-bond carbon-hydrogen coupling (4 Hz) in ethyne. However, not for all couplings lead the inclusion of zero-point vibrational corrections to better agreement with experiment.

  14. SOPPA and CCSD vibrational corrections to NMR indirect spin-spin coupling constants of small hydrocarbons

    NASA Astrophysics Data System (ADS)

    Faber, Rasmus; Sauer, Stephan P. A.

    2015-12-01

    We present zero-point vibrational corrections to the indirect nuclear spin-spin coupling constants in ethyne, ethene, cyclopropene and allene. The calculations have been carried out both at the level of the second order polarization propagator approximation (SOPPA) employing a new implementation in the DALTON program, at the density functional theory level with the B3LYP functional employing also the Dalton program and at the level of coupled cluster singles and doubles (CCSD) theory employing the implementation in the CFOUR program. Specialized coupling constant basis sets, aug-cc-pVTZ-J, have been employed in the calculations. We find that on average the SOPPA results for both the equilibrium geometry values and the zero-point vibrational corrections are in better agreement with the CCSD results than the corresponding B3LYP results. Furthermore we observed that the vibrational corrections are in the order of 5 Hz for the one-bond carbon-hydrogen couplings and about 1 Hz or smaller for the other couplings apart from the one-bond carbon-carbon coupling (11 Hz) and the two-bond carbon-hydrogen coupling (4 Hz) in ethyne. However, not for all couplings lead the inclusion of zero-point vibrational corrections to better agreement with experiment.

  15. Behavioural variation in 172 small-scale societies indicates that social learning is the main mode of human adaptation

    PubMed Central

    Mathew, Sarah; Perreault, Charles

    2015-01-01

    The behavioural variation among human societies is vast and unmatched in the animal world. It is unclear whether this variation is due to variation in the ecological environment or to differences in cultural traditions. Underlying this debate is a more fundamental question: is the richness of humans’ behavioural repertoire due to non-cultural mechanisms, such as causal reasoning, inventiveness, reaction norms, trial-and-error learning and evoked culture, or is it due to the population-level dynamics of cultural transmission? Here, we measure the relative contribution of environment and cultural history in explaining the behavioural variation of 172 Native American tribes at the time of European contact. We find that the effect of cultural history is typically larger than that of environment. Behaviours also persist over millennia within cultural lineages. This indicates that human behaviour is not predominantly determined by single-generation adaptive responses, contra theories that emphasize non-cultural mechanisms as determinants of human behaviour. Rather, the main mode of human adaptation is social learning mechanisms that operate over multiple generations. PMID:26085589

  16. Behavioural variation in 172 small-scale societies indicates that social learning is the main mode of human adaptation.

    PubMed

    Mathew, Sarah; Perreault, Charles

    2015-07-01

    The behavioural variation among human societies is vast and unmatched in the animal world. It is unclear whether this variation is due to variation in the ecological environment or to differences in cultural traditions. Underlying this debate is a more fundamental question: is the richness of humans' behavioural repertoire due to non-cultural mechanisms, such as causal reasoning, inventiveness, reaction norms, trial-and-error learning and evoked culture, or is it due to the population-level dynamics of cultural transmission? Here, we measure the relative contribution of environment and cultural history in explaining the behavioural variation of 172 Native American tribes at the time of European contact. We find that the effect of cultural history is typically larger than that of environment. Behaviours also persist over millennia within cultural lineages. This indicates that human behaviour is not predominantly determined by single-generation adaptive responses, contra theories that emphasize non-cultural mechanisms as determinants of human behaviour. Rather, the main mode of human adaptation is social learning mechanisms that operate over multiple generations. PMID:26085589

  17. Small Variations in Early-Life Environment Can Affect Coping Behaviour in Response to Foraging Challenge in the Three-Spined Stickleback

    PubMed Central

    2016-01-01

    Context An increasing concern in the face of human expansion throughout natural habitats is whether animal populations can respond adaptively when confronted with challenges like environmental change and novelty. Behavioural flexibility is an important factor in estimating the adaptive potential of both individuals and populations, and predicting the degree to which they can cope with change. Study Design This study on the three-spined stickleback (Gasterosteus aculeatus) is an empiric illustration of the degree of behavioural variation that can emerge between semi-natural systems within only a single generation. Wild-caught adult sticklebacks (P, N = 400) were randomly distributed in equal densities over 20 standardized semi-natural environments (ponds), and one year later offspring (F1, N = 652) were presented with repeated behavioural assays. Individuals were challenged to reach a food source through a novel transparent obstacle, during which exploration, activity, foraging, sociability and wall-biting behaviours were recorded through video observation. We found that coping responses of individuals from the first generation to this unfamiliar foraging challenge were related to even relatively small, naturally diversified variation in developmental environment. All measured behaviours were correlated with each other. Especially exploration, sociability and wall-biting were found to differ significantly between ponds. These differences could not be explained by stickleback density or the turbidity of the water. Findings Our findings show that a) differences in early-life environment appear to affect stickleback feeding behaviour later in life; b) this is the case even when the environmental differences are only small, within natural parameters and diversified gradually; and c) effects are present despite semi-natural conditions that fluctuate during the year. Therefore, in behaviourally plastic animals like the stickleback, the adaptive response to human

  18. Transmon-based simulator of nonlocal electron-phonon coupling: A platform for observing sharp small-polaron transitions

    NASA Astrophysics Data System (ADS)

    Stojanović, Vladimir M.; Vanević, Mihajlo; Demler, Eugene; Tian, Lin

    2014-04-01

    We propose an analog superconducting quantum simulator for a one-dimensional model featuring momentum-dependent (nonlocal) electron-phonon couplings of Su-Schrieffer-Heeger and "breathing-mode" types. Because its corresponding coupling vertex function depends on both the electron and phonon quasimomenta, this model does not belong to the realm of validity of the Gerlach-Löwen theorem that rules out any nonanalyticities in single-particle properties. The superconducting circuit behind the proposed simulator entails an array of transmon qubits and microwave resonators. By applying microwave driving fields to the qubits, a small-polaron Bloch state with an arbitrary quasimomentum can be prepared in this system within times several orders of magnitude shorter than the typical qubit decoherence times. We demonstrate that—by varying the externally tunable parameters—one can readily reach the critical coupling strength required for observing the sharp transition from a nondegenerate (single-particle) ground state corresponding to zero quasimomentum (Kgs=0) to a twofold-degenerate small-polaron ground state at nonzero quasimomenta Kgs and -Kgs. Through exact numerical diagonalization of our effective Hamiltonian, we show how this nonanalyticity is reflected in the relevant single-particle properties (ground-state energy, quasiparticle residue, average number of phonons). We also show that the proposed setup provides an ideal testbed for studying the nonequilibrium dynamics of small-polaron formation in the presence of strongly momentum-dependent electron-phonon interactions.

  19. Ligand coupling symmetry correlates with thermopower enhancement in small-molecule/nanocrystal hybrid materials.

    PubMed

    Lynch, Jared; Kotiuga, Michele; Doan-Nguyen, Vicky V T; Queen, Wendy L; Forster, Jason D; Schlitz, Ruth A; Murray, Christopher B; Neaton, Jeffrey B; Chabinyc, Michael L; Urban, Jeffrey J

    2014-10-28

    We investigate the impact of the coupling symmetry and chemical nature of organic-inorganic interfaces on thermoelectric transport in Cu2-xSe nanocrystal thin films. By coupling ligand-exchange techniques with layer-by-layer assembly methods, we are able to systematically vary nanocrystal-organic linker interfaces, demonstrating how the functionality of the polar headgroup and the coupling symmetry of the organic linkers can change the power factor (S(2)σ) by nearly 2 orders of magnitude. Remarkably, we observe that ligand-coupling symmetry has a profound effect on thermoelectric transport in these hybrid materials. We shed light on these results using intuition from a simplified model for interparticle charge transport via tunneling through the frontier orbital of a bound ligand. Our analysis indicates that ligand-coupling symmetry and binding mechanisms correlate with enhanced conductivity approaching 2000 S/cm, and we employ this concept to demonstrate among the highest power factors measured for quantum-dot based thermoelectric inorganic-organic composite materials of ∼ 30 μW/m · K(2). PMID:25211028

  20. 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.

  1. Network topology and Turing instabilities in small arrays of diffusively coupled reactors

    NASA Astrophysics Data System (ADS)

    Horsthemke, Werner; Lam, Kwan; Moore, Peter K.

    2004-08-01

    We study the effect of the network structure on the diffusion-induced instability to nonuniform steady states in arrays of diffusively coupled reactors. The kinetics is given by the Lengyel-Epstein model, and we derive the conditions for Turing instabilities in all arrays of two, three, and four reactors.

  2. Design and baseline characteristics of the 10 Small Steps Study: a randomised controlled trial of an intervention to promote healthy behaviour using a lifestyle score and personalised feedback

    PubMed Central

    2012-01-01

    Background Non-communicable diseases (NCDs) are the leading causes of death globally and are associated with a limited set of common, modifiable health behaviours: tobacco use, physical inactivity, harmful use of alcohol and unhealthy diet. General practice offers an ideal avenue for addressing such health behaviours on a population-wide basis. This paper describes the protocol of a multiple health behaviour change intervention designed for implementation in general practice and summarises the baseline characteristics of its participants. Method/Design The 10 Small Steps (10SS) study, a randomised controlled trial, involved 4,678 adult general practice patients in Queensland, Australia. Self-reported data were collected to establish the proportion of participants meeting recommended guidelines for ten health behaviours: physical activity, body mass index, alcohol, smoking and six dietary behaviours. Participants were randomised to four groups: contact at baseline only ('single intervention' and corresponding control group) and contact at baseline and 3 months ('dual intervention' and corresponding control group). At each contact the participants received a computer-tailored feedback and one page information sheet according to their allocation to intervention or control groups. Change in the intervention group compared to the control group was assessed at 3 and12 months after baseline data collection. Responses were summed to calculate an individual lifestyle score (the Prudence Score), which ranged from 0 to 10. The baseline response was 56.5% (4678 of 8343 invited participants) and the study sample was primarily female (68.7%) with an average age of 47 years. The mean Prudence Score was 5.8 (95%CI 5.75-5.85). Discussion Baseline data from the 10SS study show that nearly all participants engage in some health behaviours but relatively few adhere simultaneously to a core set of dietary and lifestyle behaviours associated with risk of NCDs. Ample scope exists to

  3. Communication: Relativistic Fock-space coupled cluster study of small building blocks of larger uranium complexes

    SciTech Connect

    Tecmer, Paweł Visscher, Lucas; Severo Pereira Gomes, André; Knecht, Stefan

    2014-07-28

    We present a study of the electronic structure of the [UO{sub 2}]{sup +}, [UO{sub 2}]{sup 2} {sup +}, [UO{sub 2}]{sup 3} {sup +}, NUO, [NUO]{sup +}, [NUO]{sup 2} {sup +}, [NUN]{sup −}, NUN, and [NUN]{sup +} molecules with the intermediate Hamiltonian Fock-space coupled cluster method. The accuracy of mean-field approaches based on the eXact-2-Component Hamiltonian to incorporate spin–orbit coupling and Gaunt interactions are compared to results obtained with the Dirac–Coulomb Hamiltonian. Furthermore, we assess the reliability of calculations employing approximate density functionals in describing electronic spectra and quantities useful in rationalizing Uranium (VI) species reactivity (hardness, electronegativity, and electrophilicity)

  4. Title: Chimeras in small, globally coupled networks: Experiments and stability analysis

    NASA Astrophysics Data System (ADS)

    Hart, Joseph D.; Bansal, Kanika; Murphy, Thomas E.; Roy, Rajarshi

    Since the initial observation of chimera states, there has been much discussion of the conditions under which these states emerge. The emphasis thus far has mainly been to analyze large networks of coupled oscillators; however, recent studies have begun to focus on the opposite limit: what is the smallest system of coupled oscillators in which chimeras can exist? We experimentally observe chimeras and other partially synchronous patterns in a network of four globally-coupled chaotic opto-electronic oscillators. By examining the equations of motion, we demonstrate that symmetries in the network topology allow a variety of synchronous states to exist, including cluster synchronous states and a chimera state. Using the group theoretical approach recently developed for analyzing cluster synchronization, we show how to derive the variational equations for these synchronous patterns and calculate their linear stability. The stability analysis gives good agreement with our experimental results. Both experiments and simulations suggest that these chimera states often appear in regions of multistability between global, cluster, and desynchronized states.

  5. Performance analysis of small capacity liquid nitrogen generator based on Joule-Thomson refrigerator coupled with air separation membrane

    NASA Astrophysics Data System (ADS)

    Piotrowska-Hajnus, Agnieszka; Chorowski, Maciej

    2012-06-01

    Joule - Thomson small capacity refrigerators supplied with gas mixture are studied theoretically and experimentally for a variety of applications. They can be especially promising when coupled with membrane air separators. We present liquid nitrogen generation system based on Joule - Thomson cooler joined with air separation membrane. Hollow fiber membrane is used for nitrogen separation from compressed and purified atmospheric air. Joule-Thomson refrigerator operates with a dedicated nitrogen - hydrocarbons mixture and provides a cooling power used for the separated nitrogen liquefaction. Special attention has been paid to a heat exchanger coupling the Joule- Thomson refrigerator with the membrane air separator. This paper describes the system design, the procedure of its working parameters optimization and tests results.

  6. Effects of acoustic alarms, designed to reduce small cetacean bycatch in gillnet fisheries, on the behaviour of North Sea fish species in a large tank.

    PubMed

    Kastelein, Ronald A; van der Heul, Sander; van der Veen, Jan; Verboom, Willem C; Jennings, Nancy; de Haan, Dick; Reijnders, Peter J H

    2007-08-01

    World-wide many cetaceans drown incidentally in fishing nets. To reduce the unwanted bycatch in gillnets, pingers (acoustic alarms) have been developed that are attached to the nets. In the European Union, pingers will be made compulsory in some areas in 2005 and in others in 2007. However, pingers may effect non-target marine fauna such as fish. Therefore in this study, the effects of seven commercially-available pingers on the behaviour of five North Sea fish species in a large tank were quantified. The species tested were: sea bass (Dicentrarchus labrax), pout (Trisopterus luscus), thicklip mullet (Chelon labrosus), herring (Clupea harengus), and cod (Gadus morhua). The fish were housed as single-species schools of 9-13 individuals in a tank. The behaviour of fish in quiet periods was compared with their behaviour during periods with active pingers. The results varied both between pingers and between fish species. Sea bass decreased their speed in response to one pinger and swam closer to the surface in response to another. Thicklip mullet swam closer to the bottom in response to two pingers and increased their swimming speed in response to one pinger. Herring swam faster in response to one pinger, and pout and cod (close relatives) showed no behavioural responses to any of the pingers. Of the seven pingers tested, four elicited responses in at least one fish species, and three elicited no responses. Whether similar responses would be elicited in these fish species in the wild, and if so, whether such responses would influence the catch rate of fisheries, cannot be derived from the results of this study. However, the results indicate the need for field studies with pingers and fish. Based on the small number of fish species tested, the present study suggests that the higher the frequency of a pinger, the less likely it is to affect the behaviour of marine fish. PMID:17316783

  7. Effects of gap junction inhibition on contraction waves in the murine small intestine in relation to coupled oscillator theory

    PubMed Central

    Huizinga, Jan D.

    2014-01-01

    Waves of contraction in the small intestine correlate with slow waves generated by the myenteric network of interstitial cells of Cajal. Coupled oscillator theory has been used to explain steplike gradients in the frequency (frequency plateaux) of contraction waves along the length of the small intestine. Inhibition of gap junction coupling between oscillators should lead to predictable effects on these plateaux and the wave dislocation (wave drop) phenomena associated with their boundaries. It is these predictions that we wished to test. We used a novel multicamera diameter-mapping system to measure contraction along 25- to 30-cm lengths of murine small intestine. There were typically two to three plateaux per length of intestine. Dislocations could be limited to the wavefronts immediately about the terminated wave, giving the appearance of a three-pronged fork, i.e., a fork dislocation; additionally, localized decreases in velocity developed across a number of wavefronts, ending with the terminated wave, which could appear as a fork, i.e., slip dislocations. The gap junction inhibitor carbenoxolone increased the number of plateaux and dislocations and decreased contraction wave velocity. In some cases, the usual frequency gradient was reversed, with a plateau at a higher frequency than its proximal neighbor; thus fork dislocations were inverted, and the direction of propagation was reversed. Heptanol had no effect on the frequency or velocity of contractions but did reduce their amplitude. To understand intestinal motor patterns, the pacemaker network of the interstitial cells of Cajal is best evaluated as a system of coupled oscillators. PMID:25501550

  8. Small coupling limit and multiple solutions to the Dirichlet problem for Yang-Mills connections in four dimensions. I

    NASA Astrophysics Data System (ADS)

    Isobe, Takeshi; Marini, Antonella

    2012-06-01

    In this paper and its sequel (Part II), we analyze the space of solutions to the ɛ-Dirichlet problem for the Yang-Mills equations on the four-dimensional disk, for small values of the coupling constant ɛ. These are in 1-1 correspondence with solutions to the Dirichlet problem for Yang-Mills, for small boundary data ɛA0. We establish a Morse theory for this non-compact variational problem and prove the existence of multiple solutions, and, also, non minimal ones. Here, we describe the problem, state the main theorems and do the first part of the proof. This consists in making the problem finite dimensional, by seeking solutions approximated by the connected sum of a minimal solution with an instanton, plus a correction term due to the boundary. By introducing an auxiliary equation, we solve the problem orthogonally to the space of the approximate solutions.

  9. Age-related effects of practice experience on collective behaviours of football players in small-sided games.

    PubMed

    Barnabé, Luís; Volossovitch, Anna; Duarte, Ricardo; Ferreira, António Paulo; Davids, Keith

    2016-08-01

    The purpose of this study was to examine whether offensive and defensive collective behaviours emerging in six-a-side football games (GK+5 vs. 5+GK) varied according to age-related practice experience of young, male players (U16, U17 and U19yrs). Players' were not instructed to implement specific tactical plans and their movement trajectories (2D analyses) were recorded using 10 GPS units. Four common measures of team dispersion investigated in previous research (surface area, stretch index, length and width of a team) were used to analyse team performance behaviours. After recording these collective variables, we used sample entropy (SampEn) and cross-sample entropy (Cross-SampEn) measures to assess the regularity and synchronization of participant actions in teams. Results demonstrated clear age-related variations in effects on the collective performance measures analysed. In attacking phases, older and more experienced players occupied a greater surface area and displayed higher values of team width and stretch index. In defensive phases, significant differences were observed in team length and stretch index. Cross-SampEn analysis demonstrated a greater synchronization between offensive and defensive surface areas and team width in older age groups (U17 and U19yrs). Data suggest how coaches can manipulate practice task constraints to enhance development of team tactical performance behaviours in developing footballers between 16 and 19yrs of age. PMID:27132155

  10. Guidelines for the Synthesis of Small-Molecule Irreversible Probes Targeting G Protein-Coupled Receptors.

    PubMed

    Jörg, Manuela; Scammells, Peter J

    2016-07-19

    Irreversible probes have been proven to be useful pharmacological tools in the study of structural and functional features in drug receptor pharmacology. They have been demonstrated to be particularly valuable for the isolation and purification of receptors. Furthermore, irreversible probes are helpful tools for the identification and characterization of binding sites, thereby supporting the advancement of rational drug design. In this Minireview, we provide insight into universal strategies and guidelines to successfully synthesize irreversible probes that target G protein-coupled receptors (GPCRs). We provide an overview of commonly used chemoreactive and photoreactive groups, and make a comparison of their properties and potential applications. Furthermore, there is a particular focus on synthetic approaches to introduce these reactive groups based on commercially available reagents. PMID:27347648

  11. Transmon-based simulator of nonlocal electron-phonon coupling: a platform for observing sharp small-polaron transitions

    NASA Astrophysics Data System (ADS)

    Stojanovic, Vladimir; Demler, Eugene; Vanevic, Mihajlo; Tian, Lin

    2014-03-01

    We propose an analog simulator for a one-dimensional model with momentum-dependent (nonlocal) electron-phonon couplings of Su-Schrieffer-Heeger and ``breathing-mode'' types. The superconducting circuit behind this simulator entails an array of transmon qubits and microwave resonators. Using a microwave-driving based protocol, small-polaron Bloch states with arbitrary quasimomentum can be prepared in this system within times several orders of magnitude shorter than the qubit decoherence time. We show that - by varying the circuit parameters - one can readily reach the critical coupling strength for observing the sharp transition from a nondegenerate single-particle ground state at zero quasimomentum (Kgs = 0) to a twofold degenerate small-polaron ground state corresponding to equal and opposite (nonzero) quasimomenta Kgs and -Kgs . Through exact diagonalization of our effective model, we show how this nonanalyticity is reflected in the relevant single-particle properties (ground-state energy, quasiparticle residue, average number of phonons). Our work paves the way for understanding the physical implications of strongly momentum-dependent electron-phonon interactions. Supported by the SNSF.

  12. 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

  13. Influence of gate metal engineering on small-signal and noise behaviour of silicon nanowire MOSFET for low-noise amplifiers

    NASA Astrophysics Data System (ADS)

    Gupta, Neha; Chaujar, Rishu

    2016-08-01

    In this paper, we have investigated the small-signal behaviour and RF noise performance of gate electrode workfunction engineered (GEWE) silicon nanowire (SiNW) MOSFET, and the results so obtained are simultaneously compared with SiNW and conventional MOSFET at THz frequency range. This work examines reflection and transmission coefficients, noise conductance, minimum noise figure and cross-correlation factor. Results reveal significant reduction in input/output reflection coefficient and an increase in forward/reverse transmission coefficient owing to improved transconductance in GEWE-SiNW in comparison with conventional counterparts. It is also observed that minimum noise figure and noise conductance of GEWE-SiNW is reduced by 17.4 and 31.2 %, respectively, in comparison with SiNW, thus fortifying its potential application for low-noise amplifiers (LNAs) at radio frequencies. Moreover, the efficacy of gate metal workfunction engineering is also studied and the results validate that tuning of workfunction difference results further improvement in device small-signal behaviour and noise performance.

  14. Metabolic coupling of two small-molecule thiols programs the biosynthesis of lincomycin A.

    PubMed

    Zhao, Qunfei; Wang, Min; Xu, Dongxiao; Zhang, Qinglin; Liu, Wen

    2015-02-01

    Low-molecular-mass thiols in organisms are well known for their redox-relevant role in protection against various endogenous and exogenous stresses. In eukaryotes and Gram-negative bacteria, the primary thiol is glutathione (GSH), a cysteinyl-containing tripeptide. In contrast, mycothiol (MSH), a cysteinyl pseudo-disaccharide, is dominant in Gram-positive actinobacteria, including antibiotic-producing actinomycetes and pathogenic mycobacteria. MSH is equivalent to GSH, either as a cofactor or as a substrate, in numerous biochemical processes, most of which have not been characterized, largely due to the dearth of information concerning MSH-dependent proteins. Actinomycetes are able to produce another thiol, ergothioneine (EGT), a histidine betaine derivative that is widely assimilated by plants and animals for variable physiological activities. The involvement of EGT in enzymatic reactions, however, lacks any precedent. Here we report that the unprecedented coupling of two bacterial thiols, MSH and EGT, has a constructive role in the biosynthesis of lincomycin A, a sulfur-containing lincosamide (C8 sugar) antibiotic that has been widely used for half a century to treat Gram-positive bacterial infections. EGT acts as a carrier to template the molecular assembly, and MSH is the sulfur donor for lincomycin maturation after thiol exchange. These thiols function through two unusual S-glycosylations that program lincosamide transfer, activation and modification, providing the first paradigm for EGT-associated biochemical processes and for the poorly understood MSH-dependent biotransformations, a newly described model that is potentially common in the incorporation of sulfur, an element essential for life and ubiquitous in living systems. PMID:25607359

  15. An interface for the direct coupling of small liquid samples to AMS

    NASA Astrophysics Data System (ADS)

    Ognibene, T. J.; Thomas, A. T.; Daley, P. F.; Bench, G.; Turteltaub, K. W.

    2015-10-01

    We describe the moving wire interface attached to the 1-MV AMS system at LLNL's Center for Accelerator Mass Spectrometry for the analysis of nonvolatile liquid samples as either discrete drops or from the direct output of biochemical separatory instrumentation, such as high-performance liquid chromatography (HPLC). Discrete samples containing at least a few 10 s of nanograms of carbon and as little as 50 zmol 14C can be measured with a 3-5% precision in a few minutes. The dynamic range of our system spans approximately 3 orders in magnitude. Sample to sample memory is minimized by the use of fresh targets for each discrete sample or by minimizing the amount of carbon present in a peak generated by an HPLC containing a significant amount of 14C. Liquid sample AMS provides a new technology to expand our biomedical AMS program by enabling the capability to measure low-level biochemicals in extremely small samples that would otherwise be inaccessible.

  16. Understanding Small-Molecule Interactions in Metal-Organic Frameworks: Coupling Experiment with Theory.

    PubMed

    Lee, Jason S; Vlaisavljevich, Bess; Britt, David K; Brown, Craig M; Haranczyk, Maciej; Neaton, Jeffrey B; Smit, Berend; Long, Jeffrey R; Queen, Wendy L

    2015-10-14

    Metal-organic frameworks (MOFs) have gained much attention as next-generation porous media for various applications, especially gas separation/storage, and catalysis. New MOFs are regularly reported; however, to develop better materials in a timely manner for specific applications, the interactions between guest molecules and the internal surface of the framework must first be understood. A combined experimental and theoretical approach is presented, which proves essential for the elucidation of small-molecule interactions in a model MOF system known as M2 (dobdc) (dobdc(4-) = 2,5-dioxido-1,4-benzenedicarboxylate; M = Mg, Mn, Fe, Co, Ni, Cu, or Zn), a material whose adsorption properties can be readily tuned via chemical substitution. It is additionally shown that the study of extensive families like this one can provide a platform to test the efficacy and accuracy of developing computational methodologies in slightly varying chemical environments, a task that is necessary for their evolution into viable, robust tools for screening large numbers of materials. PMID:26033176

  17. An interface for the direct coupling of small liquid samples to AMS

    DOE PAGESBeta

    Ognibene, T. J.; Thomas, A. T.; Daley, P. F.; Bench, G.; Turteltaub, K. W.

    2015-05-28

    We describe the moving wire interface attached to the 1-MV AMS system at LLNL’s Center for Accelerator Mass Spectrometry for the analysis of nonvolatile liquid samples as either discrete drops or from the direct output of biochemical separatory instrumentation, such as high-performance liquid chromatography (HPLC). Discrete samples containing at least a few 10 s of nanograms of carbon and as little as 50 zmol 14C can be measured with a 3–5% precision in a few minutes. The dynamic range of our system spans approximately 3 orders in magnitude. Sample to sample memory is minimized by the use of fresh targetsmore » for each discrete sample or by minimizing the amount of carbon present in a peak generated by an HPLC containing a significant amount of 14C. As a result, liquid sample AMS provides a new technology to expand our biomedical AMS program by enabling the capability to measure low-level biochemicals in extremely small samples that would otherwise be inaccessible.« less

  18. An interface for the direct coupling of small liquid samples to AMS

    SciTech Connect

    Ognibene, T. J.; Thomas, A. T.; Daley, P. F.; Bench, G.; Turteltaub, K. W.

    2015-05-28

    We describe the moving wire interface attached to the 1-MV AMS system at LLNL’s Center for Accelerator Mass Spectrometry for the analysis of nonvolatile liquid samples as either discrete drops or from the direct output of biochemical separatory instrumentation, such as high-performance liquid chromatography (HPLC). Discrete samples containing at least a few 10 s of nanograms of carbon and as little as 50 zmol 14C can be measured with a 3–5% precision in a few minutes. The dynamic range of our system spans approximately 3 orders in magnitude. Sample to sample memory is minimized by the use of fresh targets for each discrete sample or by minimizing the amount of carbon present in a peak generated by an HPLC containing a significant amount of 14C. As a result, liquid sample AMS provides a new technology to expand our biomedical AMS program by enabling the capability to measure low-level biochemicals in extremely small samples that would otherwise be inaccessible.

  19. Target delivery of small interfering RNAs with vitamin E-coupled nanoparticles for treating hepatitis C.

    PubMed

    Duan, Liang; Yan, Yan; Liu, Jingyi; Wang, Bo; Li, Pu; Hu, Qin; Chen, Weixian

    2016-01-01

    RNA interference (RNAi) represents a promising strategy for the treatment of HCV infection. However, the development of an effective system for in vivo delivery of small interfering RNA (siRNA) to target organ remains a formidable challenge. Here, we develop a unique nanoparticle platform (VE-DC) composed of α-tocopherol (vitamin E) and cholesterol-based cationic liposomes (DOTAP-Chol) for systemic delivery of siRNAs to the liver. A HCV-replicable cell line, Huh7.5.1-HCV, and a transient HCV core expressing cell line, Huh7.5.1-Core, were constructed and used to assess the in vitro anti-HCV activity of VE-DC/siRNAs. A transient in vivo HCV model was also constructed by hydrodynamic injection of pCDNA3.1(+)-3FLAG-Core (pCore-3FLAG) plasmid expressing core protein or pGL3-5'UTR-luciferase (pGL3-5'UTR-luc) plasmid expressing luciferase driven by HCV 5'UTR. Nanoscale VE-DC/siRNA was intravenously injected to assess the liver-targeting property as well as antiviral activity. The nanoscale VE-DC effectively exerted an anti-HCV activity in the in vitro cell models. Post-administration of VE-DC/siRNAs also effectively delivered siRNAs to the liver, suppressing core protein production and firefly luciferase activity, without inducing an innate immunity response or off-target and toxicity effects. The VE-DC platform has high potential as a vehicle for delivery of siRNAs to the liver for gene therapy for targeting hepatitis C. PMID:27113197

  20. Target delivery of small interfering RNAs with vitamin E-coupled nanoparticles for treating hepatitis C

    PubMed Central

    Duan, Liang; Yan, Yan; Liu, Jingyi; Wang, Bo; Li, Pu; Hu, Qin; Chen, Weixian

    2016-01-01

    RNA interference (RNAi) represents a promising strategy for the treatment of HCV infection. However, the development of an effective system for in vivo delivery of small interfering RNA (siRNA) to target organ remains a formidable challenge. Here, we develop a unique nanoparticle platform (VE-DC) composed of α-tocopherol (vitamin E) and cholesterol-based cationic liposomes (DOTAP-Chol) for systemic delivery of siRNAs to the liver. A HCV-replicable cell line, Huh7.5.1-HCV, and a transient HCV core expressing cell line, Huh7.5.1-Core, were constructed and used to assess the in vitro anti-HCV activity of VE-DC/siRNAs. A transient in vivo HCV model was also constructed by hydrodynamic injection of pCDNA3.1(+)-3FLAG-Core (pCore-3FLAG) plasmid expressing core protein or pGL3-5′UTR-luciferase (pGL3-5′UTR-luc) plasmid expressing luciferase driven by HCV 5′UTR. Nanoscale VE-DC/siRNA was intravenously injected to assess the liver-targeting property as well as antiviral activity. The nanoscale VE-DC effectively exerted an anti-HCV activity in the in vitro cell models. Post-administration of VE-DC/siRNAs also effectively delivered siRNAs to the liver, suppressing core protein production and firefly luciferase activity, without inducing an innate immunity response or off-target and toxicity effects. The VE-DC platform has high potential as a vehicle for delivery of siRNAs to the liver for gene therapy for targeting hepatitis C. PMID:27113197

  1. Irregular macroscopic dynamics due to chimera states in small-world networks of pulse-coupled oscillators

    NASA Astrophysics Data System (ADS)

    Rothkegel, A.; Lehnertz, K.

    2014-05-01

    We study the collective dynamics of excitatory integrate-and-fire-like oscillators interacting via δ-pulses on a small-world network. The oscillators are endowed with refractory periods and time delays. For weak coupling strengths, the network self-organizes into synchronous and asynchronous regions. Such chimera states allow for two separate routes to synchrony/asynchrony. In addition to the loss of stability of either synchronous or asynchronous regions mediated by long-ranged connections, regions may grow or shrink mediated by the lattice structure. The interplay between these behaviors leads to controlled total sizes of asynchronous regions or to an alternation of synchronization and desynchronization phenomena with irregular macroscopic observables.

  2. 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.

  3. Four-way coupled simulations of small particles in turbulent channel flow: The effects of particle shape and Stokes number

    SciTech Connect

    Zhao, F.; Wachem, B. G. M. van; George, W. K.

    2015-08-15

    This paper investigates the effects of particle shape and Stokes number on the behaviour of non-spherical particles in turbulent channel flow. Although there are a number of studies concerning spherical particles in turbulent flows, most important applications occurring in process, energy, and pharmaceutical industries deal with non-spherical particles. The computation employs a unique and novel four-way coupling with the Lagrangian point-particle approach. The fluid phase at low Reynolds number (Re{sub τ} = 150) is modelled by direct numerical simulation, while particles are tracked individually. Inter-particle and particle-wall collisions are also taken into account. To explore the effects of particles on the flow turbulence, the statistics of the fluid flow such as the fluid velocity, the terms in the turbulence kinetic energy equation, the slip velocity between the two phases and velocity correlations are analysed considering ellipsoidal particles with different inertia and aspect ratio. The results of the simulations show that the turbulence is considerably attenuated, even in the very dilute regime. The reduction of the turbulence intensity is predominant near the turbulence kinetic energy peak in the near wall region, where particles preferentially accumulate. Moreover, the elongated shape of ellipsoids strengthens the turbulence attenuation. In simulations with ellipsoidal particles, the fluid-particle interactions strongly depend on the orientation of the ellipsoids. In the near wall region, ellipsoids tend to align predominantly within the streamwise (x) and wall-normal (y) planes and perpendicular to the span-wise direction, whereas no preferential orientation in the central region of the channel is observed. Important conclusions from this work include the effective viscosity of the flow is not affected, the direct dissipation by the particles is negligible, and the primary mechanism by which the particles affect the flow is by altering the turbulence

  4. Four-way coupled simulations of small particles in turbulent channel flow: The effects of particle shape and Stokes number

    NASA Astrophysics Data System (ADS)

    Zhao, F.; George, W. K.; van Wachem, B. G. M.

    2015-08-01

    This paper investigates the effects of particle shape and Stokes number on the behaviour of non-spherical particles in turbulent channel flow. Although there are a number of studies concerning spherical particles in turbulent flows, most important applications occurring in process, energy, and pharmaceutical industries deal with non-spherical particles. The computation employs a unique and novel four-way coupling with the Lagrangian point-particle approach. The fluid phase at low Reynolds number (Reτ = 150) is modelled by direct numerical simulation, while particles are tracked individually. Inter-particle and particle-wall collisions are also taken into account. To explore the effects of particles on the flow turbulence, the statistics of the fluid flow such as the fluid velocity, the terms in the turbulence kinetic energy equation, the slip velocity between the two phases and velocity correlations are analysed considering ellipsoidal particles with different inertia and aspect ratio. The results of the simulations show that the turbulence is considerably attenuated, even in the very dilute regime. The reduction of the turbulence intensity is predominant near the turbulence kinetic energy peak in the near wall region, where particles preferentially accumulate. Moreover, the elongated shape of ellipsoids strengthens the turbulence attenuation. In simulations with ellipsoidal particles, the fluid-particle interactions strongly depend on the orientation of the ellipsoids. In the near wall region, ellipsoids tend to align predominantly within the streamwise (x) and wall-normal (y) planes and perpendicular to the span-wise direction, whereas no preferential orientation in the central region of the channel is observed. Important conclusions from this work include the effective viscosity of the flow is not affected, the direct dissipation by the particles is negligible, and the primary mechanism by which the particles affect the flow is by altering the turbulence

  5. Small coupling limit and multiple solutions to the Dirichlet problem for Yang-Mills connections in four dimensions. II

    NASA Astrophysics Data System (ADS)

    Isobe, Takeshi; Marini, Antonella

    2012-06-01

    In this paper, we complete the proof of the existence of multiple solutions (and, in particular, non minimal ones), to the ɛ-Dirichlet problem obtained as a variational problem for the SU(2)ɛ-Yang-Mills functional. This is equivalent to proving the existence of multiple solutions to the Dirichlet problem for the SU(2)-Yang-Mills functional with small boundary data. In the first paper of this series this non-compact variational problem is transformed into the finite-dimensional problem of finding the critical points of the function J_{ɛ }({q}), which is essentially the Yang-Mills functional evaluated on the approximate solutions, constructed via a gluing technique. In the present paper, we establish a Morse theory for J_{ɛ }({q}), by means of Ljusternik-Schnirelmann theory, thus complete the proofs of Theorems 1-3 given by Isobe and Marini ["Small coupling limit and multiple solutions to the Dirichlet Problem for Yang-Mills connections in 4 dimensions - Part I," J. Math. Phys. 53, 063706 (2012)], 10.1063/1.4728211.

  6. Direct coupling of annexin A5 to VSOP yields small, protein-covered nanoprobes for MR imaging of apoptosis.

    PubMed

    Figge, Lena; Appler, Franziska; Chen, Howard H; Sosnovik, David E; Schnorr, Jörg; Seitz, Oliver; Taupitz, Matthias; Hamm, Bernd; Schellenberger, Eyk

    2014-01-01

    Annexin A5 (Anx) has been extensively used for imaging apoptosis by single-photon emission computed tomography, positron emission tomography, optical imaging and MRI. Recently we introduced ultrasmall Anx-VSOP (very small iron oxide particles)--the smallest high-relaxivity probe for MRI of apoptosis. Here we present a simplified method for the direct coupling of Anx to VSOP, which resulted in nanoparticles that are nearly completely covered with human Anx. These superparamagnetic nanoparticles are only 14.4 ± 2.3 nm in diameter and have higher T2* relaxivity. Compared with existing probes, the small size and the Anx shielding provide prerequisites for good biocompatibility and bioavailability in target tissues. In vitro characterization showed specific binding of Anx-VSOP to apoptotic cells, which led to a signal loss in T2*-weighted MR measurements, while control probe M1324-VSOP produced no such change. Exploratory MRI was done in vivo in a cardiac model of ischemia-reperfusion damage illustrating the potential of the probe for future studies. PMID:24706613

  7. In vivo gene silencing of CD81 by lentiviral expression of small interference RNAs suppresses cocaine-induced behaviour.

    PubMed

    Bahi, Amine; Boyer, Frederic; Kolira, Manoj; Dreyer, Jean-Luc

    2005-03-01

    The tetraspanin CD81 is induced in the mesolimbic dopaminergic pathway after cocaine administration. To further investigate its role, a regulatable lentivirus (Lenti-CD81) bearing the CD81 gene under the control of a tetracycline-inducible promoter and lentiviruses expressing short hairpin RNA (shRNA) targeted against CD81 (Lenti-CD81-shRNAs) have been prepared. Infection of HEK293T cells in vitro with Lenti-CD81-shRNAs resulted in 96.5% gene silencing (from quantitative real-time PCR(qRT-PCR) and immunocytochemistry). In vivo delivery of Lenti-CD81-shRNA into the nucleus accumbens or ventral tegmental area resulted in 91.3 and 94% silencing of endogenous CD81, respectively. Stereotaxic injection of Lenti-CD81 into these regions, resulting in CD81 overexpression, induced a four- to fivefold increase in locomotor activity after chronic cocaine administration, which returned to basal levels when Lenti-CD81-shRNA had been coinjected or when CD81 expression was blocked by doxycycline. Furthermore, silencing endogenous CD81 in vivo resulted in a significant decrease in locomotor activity over controls, again suppressing cocaine-induced behaviour. PMID:15715673

  8. The footprints of typhoons on seismic records and their implications on small-scale coupling mechanisms in South China Sea

    NASA Astrophysics Data System (ADS)

    Xiao, H.; Xue, M.; Yang, T.; Liu, C.; Hua, Q.; Xia, S.; Huang, H.; Le, B. M.; Huo, D.; Pan, M.; Li, L.

    2015-12-01

    By investigating the footprints of typhoons on seismic records, we can understand their contributions to seismic noises as well as to small-scale coupling mechanisms of typhoon-land and typhoon-ocean-land. We analyze the signatures of typhoon KAI-TAK and BOPHA using seismic data from the ocean-bottom seismometers (OBSs) deployed in the central basin of South China Sea by Tongji University in 2012 as well as seismic stations (IC.QIZ,HK.HKPS and RM.SZP) on lands.Our preliminary results show that typhoons mainly enhance microseisms at the frequency band of ~0.1-0.5 Hz, including both long period double frequency (LPDF) and short period double frequency (SPDF) microseisms. A positive correlation observed between the amplitude of microseisms and the height of local ocean waves. Because OBSs are deployed at the bottom of ocean, single frequency (SF) microseisms are not prominent on them due to their fast attenuation with depth. During the typhoon KAI-TAK, the increase of LPDF energy is very small in OBSs while that is very high on land stations, indicating that LPDF microseisms are generated at nearby shorelines and can propagate towards the sea through the solid earth. However, the increase of SPDF energy is almost the same level for both OBSs and land stations indicating that the generation of SPDF is probably local.However, we also observe a small amount of energy arrives before the increases of the wave heights at the land station HK.HKPS. We derive that this energy may from a source that is not local: while LPDF can be generated at nearby shorelines and SPDF can be generated everywhere locally, they can both transmit through the solid part of the Earth to a station some distance away, i.e. HK.HKPS. In addition, we find that typhoons enhance not only the microseisms as expected but also the seismic energy from higher frequency bands. The spectrum amplitude during Typhoon periods, normalized by that of no-storm periods, shows that land stations produce stronger higher

  9. Coupled Spin and Shape Evolution of Small Rubble-pile Asteroids: Self-limitation of the YORP Effect

    NASA Astrophysics Data System (ADS)

    Cotto-Figueroa, Desireé; Statler, Thomas S.; Richardson, Derek C.; Tanga, Paolo

    2015-04-01

    We present the first self-consistent simulations of the coupled spin-shape evolution of small gravitational aggregates under the influence of the YORP effect. Because of YORP’s sensitivity to surface topography, even small centrifugally driven reconfigurations of aggregates can alter the YORP torque dramatically, resulting in spin evolution that can differ qualitatively from the rigid-body prediction. One-third of our simulations follow a simple evolution described as a modified YORP cycle. Two-thirds exhibit one or more of three distinct behaviors—stochastic YORP, self-governed YORP, and stagnating YORP—which together result in YORP self-limitation. Self-limitation confines rotation rates of evolving aggregates to far narrower ranges than those expected in the classical YORP cycle, greatly prolonging the times over which objects can preserve their sense of rotation. Simulated objects are initially randomly packed, disordered aggregates of identical spheres in rotating equilibrium, with low internal angles of friction. Their shape evolution is characterized by rearrangement of the entire body, including the deep interior. They do not evolve to axisymmetric top shapes with equatorial ridges. Mass loss occurs in one-third of the simulations, typically in small amounts from the ends of a prolate-triaxial body. We conjecture that YORP self-limitation may inhibit formation of top-shapes, binaries, or both, by restricting the amount of angular momentum that can be imparted to a deformable body. Stochastic YORP, in particular, will affect the evolution of collisional families whose orbits drift apart under the influence of Yarkovsky forces, in observable ways.

  10. LRRTM1-deficient mice show a rare phenotype of avoiding small enclosures—A tentative mouse model for claustrophobia-like behaviour

    PubMed Central

    Laakso, T.; Lauren, J.; Strittmatter, S.M.; Airaksinen, M.S.

    2013-01-01

    The LRRTM family proteins have been shown to act as synaptogenic cell adhesion molecules via interaction with presynaptic neurexins and are associated with neuropsychiatric disorders. LRRTM1-knockout mice have subtle morphological deficits in excitatory hippocampal synapses and were suggested to have impaired cognitive function. Here we report that LRRTM1-knockout mice exhibit an extraordinary phenotype of avoiding small enclosures. In the light–dark box, the knockout mice escape to dark through a standard opening as quickly as wild-type littermates but avoid escaping through a small doorway. While all wild-type mice spontaneously enter a small tube, most knockout mice do not. This apparent aversion to enter narrow space may explain other abnormalities such as increased time in open arms in the elevated plus maze and less visits through a tunnel in the IntelliCage. Moreover, LRRTM1-knockout mice show increased social interaction, reduced nest building and MK801-induced locomotion, and slower swim speed but normal water maze learning. Since LRRTM1 is predominantly expressed in thalamus, hippocampus and limbic cortex, specific synaptic defects in those areas presumably cause these behavioural abnormalities. PMID:23089646

  11. Prion Protein—Antibody Complexes Characterized by Chromatography-Coupled Small-Angle X-Ray Scattering

    PubMed Central

    Carter, Lester; Kim, Seung Joong; Schneidman-Duhovny, Dina; Stöhr, Jan; Poncet-Montange, Guillaume; Weiss, Thomas M.; Tsuruta, Hiro; Prusiner, Stanley B.; Sali, Andrej

    2015-01-01

    Aberrant self-assembly, induced by structural misfolding of the prion proteins, leads to a number of neurodegenerative disorders. In particular, misfolding of the mostly α-helical cellular prion protein (PrPC) into a β-sheet-rich disease-causing isoform (PrPSc) is the key molecular event in the formation of PrPSc aggregates. The molecular mechanisms underlying the PrPC-to-PrPSc conversion and subsequent aggregation remain to be elucidated. However, in persistently prion-infected cell-culture models, it was shown that treatment with monoclonal antibodies against defined regions of the prion protein (PrP) led to the clearing of PrPSc in cultured cells. To gain more insight into this process, we characterized PrP-antibody complexes in solution using a fast protein liquid chromatography coupled with small-angle x-ray scattering (FPLC-SAXS) procedure. High-quality SAXS data were collected for full-length recombinant mouse PrP [denoted recPrP(23–230)] and N-terminally truncated recPrP(89–230), as well as their complexes with each of two Fab fragments (HuM-P and HuM-R1), which recognize N- and C-terminal epitopes of PrP, respectively. In-line measurements by fast protein liquid chromatography coupled with SAXS minimized data artifacts caused by a non-monodispersed sample, allowing structural analysis of PrP alone and in complex with Fab antibodies. The resulting structural models suggest two mechanisms for how these Fabs may prevent the conversion of PrPC into PrPSc. PMID:26287631

  12. Application of a convergent, composite coupled cluster approach to bound state, adiabatic electron affinities in atoms and small molecules.

    PubMed

    Feller, David

    2016-01-01

    Benchmark quality adiabatic electron affinities for a collection of atoms and small molecules were obtained with the Feller-Peterson-Dixon composite coupled cluster theory method. Prior applications of this method demonstrated its ability to accurately predict atomization energies/heats of formation for more than 170 molecules. In the current work, the 1-particle expansion involved very large correlation consistent basis sets, ranging up to aug-cc-pV9Z (aug-cc-pV10Z for H and H2), with the goal of minimizing the residual basis set truncation error that must otherwise be approximated with extrapolation formulas. The n-particle expansion begins with coupled cluster calculations through iterative single and double excitations plus a quasiperturbative treatment of "connected" triple excitations (CCSD(T)) pushed to the complete basis set limit followed by CCSDT, CCSDTQ, or CCSDTQ5 corrections. Due to the small size of the systems examined here, it was possible in many cases to extend the n-particle expansion to the full configuration interaction wave function limit. Additional, smaller corrections associated with core/valence correlation, scalar relativity, anharmonic zero point vibrational energies, and non-adiabatic effects were also included. The overall root mean square (RMS) deviation was 0.005 eV (0.12 kcal/mol). This level of agreement was comparable to what was found with molecular heats of formation. A 95% confidence level corresponds to roughly twice the RMS value or 0.01 eV. While the atomic electron affinities are known experimentally to high accuracy, the molecular values are less certain. This contributes to the difficulty of gauging the accuracy of the theoretical results. A limited number of electron affinities were determined with the explicitly correlated CCSD(T)-F12b method. After extending the VnZ-F12 orbital basis sets with additional diffuse functions, the F12b method was found to accurately reproduce the best F/F(-) value obtained with standard

  13. Application of a convergent, composite coupled cluster approach to bound state, adiabatic electron affinities in atoms and small molecules

    NASA Astrophysics Data System (ADS)

    Feller, David

    2016-01-01

    Benchmark quality adiabatic electron affinities for a collection of atoms and small molecules were obtained with the Feller-Peterson-Dixon composite coupled cluster theory method. Prior applications of this method demonstrated its ability to accurately predict atomization energies/heats of formation for more than 170 molecules. In the current work, the 1-particle expansion involved very large correlation consistent basis sets, ranging up to aug-cc-pV9Z (aug-cc-pV10Z for H and H2), with the goal of minimizing the residual basis set truncation error that must otherwise be approximated with extrapolation formulas. The n-particle expansion begins with coupled cluster calculations through iterative single and double excitations plus a quasiperturbative treatment of "connected" triple excitations (CCSD(T)) pushed to the complete basis set limit followed by CCSDT, CCSDTQ, or CCSDTQ5 corrections. Due to the small size of the systems examined here, it was possible in many cases to extend the n-particle expansion to the full configuration interaction wave function limit. Additional, smaller corrections associated with core/valence correlation, scalar relativity, anharmonic zero point vibrational energies, and non-adiabatic effects were also included. The overall root mean square (RMS) deviation was 0.005 eV (0.12 kcal/mol). This level of agreement was comparable to what was found with molecular heats of formation. A 95% confidence level corresponds to roughly twice the RMS value or 0.01 eV. While the atomic electron affinities are known experimentally to high accuracy, the molecular values are less certain. This contributes to the difficulty of gauging the accuracy of the theoretical results. A limited number of electron affinities were determined with the explicitly correlated CCSD(T)-F12b method. After extending the VnZ-F12 orbital basis sets with additional diffuse functions, the F12b method was found to accurately reproduce the best F/F- value obtained with standard

  14. Monitoring of coupling distribution and small Short-term SSEs in southwest Japan based on GEONET data

    NASA Astrophysics Data System (ADS)

    Fujita, A.; Ikuta, R.; Satomura, M.; Shimada, S.; Kato, T.

    2011-12-01

    In the south-western part of Japan, there occur episodic tremor and slip beneath Nankai trough. These short-term slow slip events (S-SSEs) especially in Tokai region are known to be very small and hard to detect by GPS. Our study is a trial for monitoring these S-SSEs by GPS data. We applied geodetic inversion to three dimensional daily GPS positioning data for 15 years from 1996 to 2010 which were provided by Geospatial Information Authority (GSI) to detect inter-plate slip as follows: 1. Correction of offsets in the GPS time series by antennae maintenance and earthquakes. 2. Principal component analysis (PCA) of the time series to remove common mode error between all the sites. 3. Taking difference between a couple of every 10 days-long averages with a gap of 1 week. 4. Adopted Bayesian inversion method proposed by Yabuki and Matsuura [1992] to the above data. Solving this inverse problem, we adopted a priori information which suppressed the slips on the fault surface without enough solvability. The slip axis was limited in the direction of the plate convergence of N45W but both polarities were arrowed. Estimated zero-slip means a stable slip of the plate boundary by rigid plate convergent rate. Positive slip means drug of hanging plate by the subducting plate and negative slip means that the velocity of the reverse faulting exceeds that of the plate convergence. After-slip and slow slips are two examples of negative slip. The results of the analysis showed following facts. S-SSEs should have occurred without tremors in the region beneath Kii-channel where no tremor or long-term SSE has been reported. S-SSEs seem to have occurred on the down-dip extension of the tremor in east side of Kii-channel. The region of strong inter-plate coupling has activity of deep low-frequency tremors on the down dip extension. The temporal as well as the spatial relations between S-SSEs and tremors should be analyzed to understand the mechanism of their occurrence. Moreover, the

  15. LDV measurement of small nonlinearities in flat and curved membranes. A model for eardrum nonlinear acoustic behaviour

    NASA Astrophysics Data System (ADS)

    Kilian, Gladiné; Pieter, Muyshondt; Joris, Dirckx

    2016-06-01

    Laser Doppler Vibrometry is an intrinsic highly linear measurement technique which makes it a great tool to measure extremely small nonlinearities in the vibration response of a system. Although the measurement technique is highly linear, other components in the experimental setup may introduce nonlinearities. An important source of artificially introduced nonlinearities is the speaker, which generates the stimulus. In this work, two correction methods to remove the effects of stimulus nonlinearity are investigated. Both correction methods were found to give similar results but have different pros and cons. The aim of this work is to investigate the importance of the conical shape of the eardrum as a source of nonlinearity in hearing. We present measurements on flat and indented membranes. The data shows that the curved membrane exhibit slightly higher levels of nonlinearity compared to the flat membrane.

  16. Spin-orbit coupling calculations with the two-component normalized elimination of the small component method

    NASA Astrophysics Data System (ADS)

    Filatov, Michael; Zou, Wenli; Cremer, Dieter

    2013-07-01

    A new algorithm for the two-component Normalized Elimination of the Small Component (2cNESC) method is presented and tested in the calculation of spin-orbit (SO) splittings for a series of heavy atoms and their molecules. The 2cNESC is a Dirac-exact method that employs the exact two-component one-electron Hamiltonian and thus leads to exact Dirac SO splittings for one-electron atoms. For many-electron atoms and molecules, the effect of the two-electron SO interaction is modeled by a screened nucleus potential using effective nuclear charges as proposed by Boettger [Phys. Rev. B 62, 7809 (2000), 10.1103/PhysRevB.62.7809]. The use of the screened nucleus potential for the two-electron SO interaction leads to accurate spinor energy splittings, for which the deviations from the accurate Dirac Fock-Coulomb values are on the average far below the deviations observed for other effective one-electron SO operators. For hydrogen halides HX (X = F, Cl, Br, I, At, and Uus) and mercury dihalides HgX2 (X = F, Cl, Br, I) trends in spinor energies and SO splittings as obtained with the 2cNESC method are analyzed and discussed on the basis of coupling schemes and the electronegativity of X.

  17. Analysis of hyperbolic signatures from small discontinuities using an UWB ground-coupled radar: FDTD simulations and field experiments

    NASA Astrophysics Data System (ADS)

    Sagnard, Florence; Tebchrany, Elias; Baltazart, Vincent

    2013-04-01

    Ground penetrating radar (GPR) is a well-known non-destructive technique based on electromagnetic wave propagation that is able to detect by reflection or scattering of waves dielectric discontinuities in the underground. Our application is mainly concerned with civil engineering to perform supervision, inventory, and soil characterization. Because the air-coupled radar suffers from a significant reflection at the ground interface that reduces energy transfer of electromagnetic radiation in the sub-surface and penetration depth, we have developed an ultra-wide band (UWB) ground-coupled radar made of a pair of partially shielded compact planar bowtie slot antennas. As the antenna dimension (36*23 cm2) is close to the A4 sheet size, the maturity of the microstrip technology has allowed to design a particular geometry on the FR4 substrate (h=1.5 mm) which is able to operate at frequencies from 460 MHz to beyond 4 GHz in air. Contrary to a commercial GPR where details on antenna design are not available, it appears here possible to know and control the radiation characteristics and develop full-wave FDTD modeling that can represent field experiments for comparisons and analyses. The objective of this work is to improve, by means of a parametric study, the knowledge of physical phenomena involved in dielectric polarization when waves interact with buried discontinuities and particularly cracks, pipes, delaminations that can be distinguished by their shape, size, dielectric contrast with the surrounding medium, orientation relative to the electric field… Thus, we have first characterized by FDTD modeling and field measurements in a wet sand the radar link in two perpendicular polarizations (parallel and mirror) in the presence of a common soil (epsilon'=5.5, sigma=0.01 S/m) considering variable offsets. Afterwards, we have studied and analyzed the hyperbola signatures generated by the presence of buried canonical objects (pipes, strips) with several dielectric

  18. Working With What We’ve Got: Perceptions of Barriers and Supports Among Small-Metropolitan Same-Sex Adopting Couples

    PubMed Central

    Kinkler, Lori A.; Goldberg, Abbie E.

    2011-01-01

    In seeking to adopt, lesbians and gay men may confront various barriers and obstacles. Ideally they have access to a variety of support resources that can help to buffer the negative effects of these barriers. However, lesbians and gay men living in small-metropolitan communities may have limited access to support resources. The current qualitative study examined the perceptions of 37 same-sex couples who were pursuing adoption while living outside of large metropolitan cities, with attention to the barriers these couples encountered during the adoption process, and the resources they drew upon to cope with such challenges. Findings indicated that same sex couples living in small-metropolitan areas confronted several major barriers in the adoption process, such as a lack of geographically accessible gay-friendly adoption agencies. Despite limited access to support, participants showed evidence of notable resourcefulness. For example, participants with limited access to formal support groups sought out informal supports instead. PMID:21949461

  19. Working With What We've Got: Perceptions of Barriers and Supports Among Small-Metropolitan Same-Sex Adopting Couples.

    PubMed

    Kinkler, Lori A; Goldberg, Abbie E

    2011-10-01

    In seeking to adopt, lesbians and gay men may confront various barriers and obstacles. Ideally they have access to a variety of support resources that can help to buffer the negative effects of these barriers. However, lesbians and gay men living in small-metropolitan communities may have limited access to support resources. The current qualitative study examined the perceptions of 37 same-sex couples who were pursuing adoption while living outside of large metropolitan cities, with attention to the barriers these couples encountered during the adoption process, and the resources they drew upon to cope with such challenges. Findings indicated that same sex couples living in small-metropolitan areas confronted several major barriers in the adoption process, such as a lack of geographically accessible gay-friendly adoption agencies. Despite limited access to support, participants showed evidence of notable resourcefulness. For example, participants with limited access to formal support groups sought out informal supports instead. PMID:21949461

  20. Current-voltage relations of sodium-coupled sugar transport across the apical membrane of Necturus small intestine.

    PubMed

    Lapointe, J Y; Hudson, R L; Schultz, S G

    1986-01-01

    The current-voltage (I-V) relations of the rheogenic Na-sugar cotransport mechanism at the apical membrane of Necturus small intestine were determined from the relations between the electrical potential difference across the apical membrane, psi mc, and that across the entire epithelium, psi ms, when the latter was varied over the range +/- 200 mV, under steady conditions in the presence of galactose and after the current across the apical membrane carried by the cotransporter, ImSNa, is blocked by the addition of phloridzin to the mucosal solution. ImSNa was found to be strongly dependent upon psi mc over the range -50 mV less than psi mc less than EmSNa where EmSNa is the "zero current" or "reversal" potential. Over the range of values of psi mc encountered under physiological conditions the cotransporter may be modeled as a conductance in series with an electromotive force so that ImSNa = gmSNa (EmSNa - psi mc) where gmSNa is the contribution of this mechanism to the conductance of the apical membrane and is "near constant." In several instances ImSNa "saturated" at large hyperpolarizing or depolarizing values of psi mc. The values of EmSNa determined in the presence of 1, 5, and 15 mM galactose strongly suggest that if the Na-galactose cotransporters are kinetically homogeneous, the stoichiometry of this coupled process is unity. Finally, the shapes of the observed I-V relations are consistent with the predictions of a simple kinetic model which conforms with current notions regarding the mechanico-kinetic properties of this cotransport process. PMID:3820278

  1. Comparison of light out-coupling enhancements in single-layer blue-phosphorescent organic light emitting diodes using small-molecule or polymer hosts

    SciTech Connect

    Chang, Yung-Ting; Liu, Shun-Wei; Yuan, Chih-Hsien; Lee, Chih-Chien; Ho, Yu-Hsuan; Wei, Pei-Kuen; Chen, Kuan-Yu; Lee, Yi-Ting; Wu, Min-Fei; Chen, Chin-Ti E-mail: chihiwu@cc.ee.ntu.edu.tw; Wu, Chih-I E-mail: chihiwu@cc.ee.ntu.edu.tw

    2013-11-07

    Single-layer blue phosphorescence organic light emitting diodes (OLEDs) with either small-molecule or polymer hosts are fabricated using solution process and the performances of devices with different hosts are investigated. The small-molecule device exhibits luminous efficiency of 14.7 cd/A and maximum power efficiency of 8.39 lm/W, which is the highest among blue phosphorescence OLEDs with single-layer solution process and small molecular hosts. Using the same solution process for all devices, comparison of light out-coupling enhancement, with brightness enhancement film (BEF), between small-molecule and polymer based OLEDs is realized. Due to different dipole orientation and anisotropic refractive index, polymer-based OLEDs would trap less light than small molecule-based OLEDs internally, about 37% better based simulation results. In spite of better electrical and spectroscopic characteristics, including ambipolar characteristics, higher carrier mobility, higher photoluminescence quantum yield, and larger triplet state energy, the overall light out-coupling efficiency of small molecule-based devices is worse than that of polymer-based devices without BEF. However, with BEF for light out-coupling enhancement, the improved ratio in luminous flux and luminous efficiency for small molecule based device is 1.64 and 1.57, respectively, which are significantly better than those of PVK (poly-9-vinylcarbazole) devices. In addition to the theoretical optical simulation, the experimental data also confirm the origins of differential light-outcoupling enhancement. The maximum luminous efficiency and power efficiency are enhanced from 14.7 cd/A and 8.39 lm/W to 23 cd/A and 13.2 lm/W, respectively, with laminated BEF, which are both the highest so far for single-layer solution-process blue phosphorescence OLEDs with small molecule hosts.

  2. Combining density functional theory (DFT) and collision cross-section (CCS) calculations to analyze the gas-phase behaviour of small molecules and their protonation site isomers.

    PubMed

    Boschmans, Jasper; Jacobs, Sam; Williams, Jonathan P; Palmer, Martin; Richardson, Keith; Giles, Kevin; Lapthorn, Cris; Herrebout, Wouter A; Lemière, Filip; Sobott, Frank

    2016-06-20

    Electrospray ion mobility-mass spectrometry (IM-MS) data show that for some small molecules, two (or even more) ions with identical sum formula and mass, but distinct drift times are observed. In spite of showing their own unique and characteristic fragmentation spectra in MS/MS, no configurational or constitutional isomers are found to be present in solution. Instead the observation and separation of such ions appears to be inherent to their gas-phase behaviour during ion mobility experiments. The origin of multiple drift times is thought to be the result of protonation site isomers ('protomers'). Although some important properties of protomers have been highlighted by other studies, correlating the experimental collision cross-sections (CCSs) with calculated values has proven to be a major difficulty. As a model, this study uses the pharmaceutical compound melphalan and a number of related molecules with alternative (gas-phase) protonation sites. Our study combines density functional theory (DFT) calculations with modified MobCal methods (e.g. nitrogen-based Trajectory Method algorithm) for the calculation of theoretical CCS values. Calculated structures can be linked to experimentally observed signals, and a strong correlation is found between the difference of the calculated dipole moments of the protomer pairs and their experimental CCS separation. PMID:27264846

  3. Use of novel fibre-coupled radioluminescence and RADPOS dosimetry systems for total scatter factor measurements in small fields

    NASA Astrophysics Data System (ADS)

    Ploquin, N.; Kertzscher, G.; Vandervoort, E.; Cygler, J. E.; Andersen, C. E.; Francescon, P.

    2015-01-01

    A dosimetry system based on Al2O3:C radioluminescence (RL), and RADPOS, a novel 4D dosimetry system using microMOSFETs, were used to measure total scatter factors, ≤ft({{S}c,p}\\right)\\text{det}{{f\\text{clin}}}, for the CyberKnife robotic radiosugery system. New Monte Carlo calculated correction factors are presented and applied for the RL detector response for the 5, 7.5 and 10 mm collimators in order to correct for the detector geometry and increased photoelectric cross section of Al2O3:C relative to water. For comparison, measurements were also carried out using a micro MOSFET, PTW60012 diode and GAFCHROMIC® film (EBT and EBT2). Uncorrected ≤ft({{S}c,p}\\right)\\text{det}{{f\\text{clin}}}, were obtained by taking the ratio of the detector response for each collimator to that for the 60 mm diameter reference field. Published Monte Carlo calculated correction factors were applied to the RADPOS, microMOSFET and diode detector measurements to yield corrected field factors, Ω {{Q\\text{clin}},{{Q}\\text{msr}}}{{f\\text{clin}},{{f}\\text{msr}}}, following the terminology of a recent formalism introduced for small and composite field relative dosimetry. With corrections, the RL measured Ω {{Q\\text{clin}},{{Q}\\text{msr}}}{{f\\text{clin}},{{f}\\text{msr}}}, were 0.656  ±  0.002, 0.815  ±  0.002 and 0.865  ±  0.003 for the 5, 7.5 and 10 mm collimators, respectively. This was in good agreement with RADPOS corrected field factors of 0.650  ±  0.010, 0.816  ±  0.024 and 0.867  ±  0.010 for the 5, 7.5 and 10 mm collimators, respectively. Both RL and RADPOS total scatter factors agreed within approximately two standard deviations of the GAFCHROMIC film values (average of EBT and EBT2) of 0.640  ±  0.006, 0.806  ±  0.007 and 0.859  ±  0.09. Corrected total scatter factors for all dosimetry systems agreed within one standard deviation for collimator sizes 10-60 mm. Our study suggests that the micro

  4. How does Australia's largest dolphin-watching industry affect the behaviour of a small and resident population of Indo-Pacific bottlenose dolphins?

    PubMed

    Steckenreuter, Andre; Möller, Luciana; Harcourt, Robert

    2012-04-30

    The small, genetically distinct population of Indo-Pacific bottlenose dolphins (Tursiops aduncus) in Port Stephens, New South Wales (NSW), is the target of the largest dolphin-watching industry in Australia and is located within the Port Stephens - Great Lakes Marine Park that was created in 2005. The effects of this industry have been identified as of significant management importance by the Marine Parks Authority NSW. Accordingly, the impact of commercial dolphin-watching boats was investigated from boat-based surveys from August 2008 to August 2009. Presence of dolphin-watching boats altered both the dolphins' behavioural states and activity budgets. Dolphins spent 66.5% less time feeding and 44.2% less time socialising, spent four times more milling, and were never observed to rest in the presence of dolphin-watching boats. Moreover, dolphin groups were more cohesive during dolphin-watching boat encounters and dolphins tended to avoid tour boats. These effects were exacerbated as the number of boats increased and the distance from boats decreased. The rate of approach was high with boats approaching each dolphin group three times per day in winter and six times in summer. Moreover, groups of dolphins with newborns were approached closer than state regulated minimum approach distances in nine out of ten encounters. Globally, dolphin-watching industries frequent small resident groups of coastal dolphins and effects are likely to be similar. We suggest that existing controls are inadequate and that these together with additional regulations be enforced by a regular presence of authorities. We suggest no more than one dolphin-watching boat within 50 m of a group of dolphins, or 100 m if calves are present. Operating times of dolphin-watching boats should be restricted in numbers after 1 pm, i.e., during preferred foraging times for dolphins. Additionally, exclusion zones should be considered to reduce pressure on dolphins undertaking critical activities such as

  5. Fano-like resonance emerging from magnetic and electric plasmon mode coupling in small arrays of gold particles.

    PubMed

    Bakhti, Saïd; Tishchenko, Alexandre V; Zambrana-Puyalto, Xavier; Bonod, Nicolas; Dhuey, Scott D; Schuck, P James; Cabrini, Stefano; Alayoglu, Selim; Destouches, Nathalie

    2016-01-01

    In this work we theoretically and experimentally analyze the resonant behavior of individual 3 × 3 gold particle oligomers illuminated under normal and oblique incidence. While this structure hosts both dipolar and quadrupolar electric and magnetic delocalized modes, only dipolar electric and quadrupolar magnetic modes remain at normal incidence. These modes couple into a strongly asymmetric spectral response typical of a Fano-like resonance. In the basis of the coupled mode theory, an analytical representation of the optical extinction in terms of singular functions is used to identify the hybrid modes emerging from the electric and magnetic mode coupling and to interpret the asymmetric line profiles. Especially, we demonstrate that the characteristic Fano line shape results from the spectral interference of a broad hybrid mode with a sharp one. This structure presents a special feature in which the electric field intensity is confined on different lines of the oligomer depending on the illumination wavelength relative to the Fano dip. This Fano-type resonance is experimentally observed performing extinction cross section measurements on arrays of gold nano-disks. The vanishing of the Fano dip when increasing the incidence angle is also experimentally observed in accordance with numerical simulations. PMID:27580515

  6. Fano-like resonance emerging from magnetic and electric plasmon mode coupling in small arrays of gold particles

    PubMed Central

    Bakhti, Saïd; Tishchenko, Alexandre V.; Zambrana-Puyalto, Xavier; Bonod, Nicolas; Dhuey, Scott D.; Schuck, P. James; Cabrini, Stefano; Alayoglu, Selim; Destouches, Nathalie

    2016-01-01

    In this work we theoretically and experimentally analyze the resonant behavior of individual 3 × 3 gold particle oligomers illuminated under normal and oblique incidence. While this structure hosts both dipolar and quadrupolar electric and magnetic delocalized modes, only dipolar electric and quadrupolar magnetic modes remain at normal incidence. These modes couple into a strongly asymmetric spectral response typical of a Fano-like resonance. In the basis of the coupled mode theory, an analytical representation of the optical extinction in terms of singular functions is used to identify the hybrid modes emerging from the electric and magnetic mode coupling and to interpret the asymmetric line profiles. Especially, we demonstrate that the characteristic Fano line shape results from the spectral interference of a broad hybrid mode with a sharp one. This structure presents a special feature in which the electric field intensity is confined on different lines of the oligomer depending on the illumination wavelength relative to the Fano dip. This Fano-type resonance is experimentally observed performing extinction cross section measurements on arrays of gold nano-disks. The vanishing of the Fano dip when increasing the incidence angle is also experimentally observed in accordance with numerical simulations. PMID:27580515

  7. Effect of adding small amount of inductive fields to O2, Ar/O2 capacitively coupled plasmas

    NASA Astrophysics Data System (ADS)

    Lee, Min-Hyong; Lee, Hyo-Chang; Chung, Chin-Wook

    2012-05-01

    Electron energy distribution functions (EEDFs) of low pressure O2 plasma were measured by adding small amount of coil power in a capacitive discharge. When the plasma was generated by bias power only, the measured EEDF showed a bi-Maxwellian distribution. However, when a very small coil power (a few Watts) was added, the EEDF evolved abruptly into a Maxwellian distribution, while the electron density was decreased. In an Ar/O2 mixture discharge, this EEDF evolution to the Maxwellian was also observed at a relatively higher coil power. This abrupt change in EEDFs with a very small coil power appears to be attributed to a combined effect of collisionless heating by capacitive and induced electric fields.

  8. First-principles investigation of the dissociation and coupling of methane on small copper clusters: Interplay of collision dynamics and geometric and electronic effects

    NASA Astrophysics Data System (ADS)

    Varghese, Jithin J.; Mushrif, Samir H.

    2015-05-01

    Small metal clusters exhibit unique size and morphology dependent catalytic activity. The search for alternate minimum energy pathways and catalysts to transform methane to more useful chemicals and carbon nanomaterials led us to investigate collision induced dissociation of methane on small Cu clusters. We report here for the first time, the free energy barriers for the collision induced activation, dissociation, and coupling of methane on small Cu clusters (Cun where n = 2-12) using ab initio molecular dynamics and metadynamics simulations. The collision induced activation of the stretching and bending vibrations of methane significantly reduces the free energy barrier for its dissociation. Increase in the cluster size reduces the barrier for dissociation of methane due to the corresponding increase in delocalisation of electron density within the cluster, as demonstrated using the electron localisation function topology analysis. This enables higher probability of favourable alignment of the C-H stretching vibration of methane towards regions of high electron density within the cluster and makes higher number of sites available for the chemisorption of CH3 and H upon dissociation. These characteristics contribute in lowering the barrier for dissociation of methane. Distortion and reorganisation of cluster geometry due to high temperature collision dynamics disturb electron delocalisation within them and increase the barrier for dissociation. Coupling reactions of CHx (x = 1-3) species and recombination of H with CHx have free energy barriers significantly lower than complete dehydrogenation of methane to carbon. Thus, competition favours the former reactions at high hydrogen saturation on the clusters.

  9. The coupling of runoff and dissolved organic matter transport: Insights from in situ fluorescence measurements in small streams and large rivers

    NASA Astrophysics Data System (ADS)

    Pellerin, B. A.; Bergamaschi, B. A.; Downing, B. D.; Saraceno, J.; Shanley, J. B.; Aiken, G.; Murdoch, P. S.

    2011-12-01

    Understanding dissolved organic matter (DOM) dynamics in streams and rivers can help characterize mercury transport, assess causes of drinking water issues, and lead to improved understanding of watershed source areas and carbon loads to downstream ecosystems. However, traditional sampling approaches that collect discrete concentration data at weekly to monthly intervals often fail to adequately capture hydrological pulses ranging from early snowmelt periods to short-duration rainfall events. Continuous measurements of chromophoric dissolved organic matter fluorescence (FDOM) in rivers and streams now provide an opportunity to more accurately quantify DOM loads and processes in aquatic ecosystems at a range of scales. In this study, we used continuous FDOM data from in situ sensors along with discharge data to assess the coupling of FDOM transport and runoff in small streams and large rivers. Results from headwater catchments in New England and California show that FDOM is tightly coupled with runoff, supporting strong linkages between watershed flow paths and DOM concentrations in streams. Results also show that the magnitude of FDOM response relative to runoff varies seasonally, with highest concentrations during autumn rainfall events (after leaf fall) and lower concentrations during peak snowmelt for equivalent runoff. In large river basins, FDOM dynamics are also coupled with runoff and exhibit the same seasonal variability in the magnitude of FDOM response relative to discharge. However, the peaks in FDOM typically lag runoff by several days, reflecting the influence of a variety of factors such as water residence times, reservoir releases, and connectivity to organic matter-rich riparian floodplains and wetlands. Our results show that in situ FDOM data will be important for understanding the coupling of runoff and DOM across multiple scales and could serve a critical role in monitoring, assessment and decision-making in both small and large watersheds.

  10. Modal analysis and efficient coupling of TE₀₁ mode in small-core THz Bragg fibers.

    PubMed

    Yao, H Y; Jiang, J Y; Cheng, Y S; Chen, Z Y; Her, T H; Chang, T H

    2015-10-19

    We report a design of low-loss THz Bragg fibers with a core size on the order of wavelength that operates near the cutoff frequency of its TE01 mode. We also propose a broadband Y-type mode converter based on branched rectangular metallic waveguides to facilitate coupling between the TE01 mode of the Bragg fiber and the TEM mode in free space with 60% efficiency. Our fiber holds strong promise to facilitate beam-wave interaction in gyrotron for high-efficiency THz generation. PMID:26480387

  11. Alcohol, cannabis, and methamphetamine use and other risk behaviours among Black and Coloured South African women: A small randomized trial in the Western Cape

    PubMed Central

    Wechsberg, Wendee M.; Luseno, Winnie K.; Karg, Rhonda S.; Young, Siobhan; Rodman, Nat; Myers, Bronwyn; Parry, Charles D. H.

    2008-01-01

    Background There is a pressing need for brief behavioural interventions to address the intersection of high HIV prevalence, increasing substance use, and high-risk sex practices among South African women. The primary aim of this pilot, randomized trial was to examine whether an adapted evidence-based intervention would be equally, more, or less effective at reducing HIV risk behaviours when delivered using an individual or group format. The secondary aim was to examine differences between Black and Coloured South African women across pre- and post-intervention measures of alcohol and illicit drug use and sex risk behaviours. Methods The Cape Town Women’s Health CoOp was adapted from an evidence-based intervention known as the Women’s CoOp._Study participants included Black (n=60) and Coloured (n=52) women living in the township communities of Cape Town, South Africa, who reported using illicit drugs and alcohol. Results Coloured women reported greater methamphetamine use (13 days in the past 30 days) and Black women reported mostly cannabis use (27days in the past 30 days). Although both groups reported having unprotected sex under the influence of alcohol and/or other drugs, Black women reported greater condom use and having one partner; Coloured women reported having more than one sex partner. One-month post-intervention assessments indicated significant reductions in substance use and sex risk behaviours. After controlling for baseline measures, there were no significant differences between the two intervention conditions. Conclusion Significant differences in risk behaviours were observed between Black and Coloured South African women. However, both ethnic groups were responsive to the adapted intervention and no differences were found by intervention assignment. These findings support the assertion that group interventions may be more cost-effective in reaching at-risk women in resource-scarce environments. Larger studies are needed to show efficacy and

  12. In situ response of bay productivity to nutrient loading from a small tributary: The Delaware Bay-Murderkill Estuary tidally-coupled biogeochemical reactor

    NASA Astrophysics Data System (ADS)

    Voynova, Yoana G.; Lebaron, Karine C.; Barnes, Rebecca T.; Ullman, William J.

    2015-07-01

    A small, turbid and nutrient-rich tributary, the Murderkill Estuary, and a large estuarine ecosystem, the Delaware Bay, are tightly linked and form an efficient, tidally-coupled biogeochemical reactor during the summer. Nitrate loading from the Murderkill Estuary generates an instantaneous increase in biological oxygen production in the adjacent Delaware Bay. We are able to capture this primary production response with continuous hourly measurements of dissolved oxygen, chlorophyll, and nitrate. The nitrate influxes from the Murderkill support primary production rates in the Delaware Bay margins that are twice as high as the average production rates measured in the central Bay regions. This elevates chlorophyll in the Bay margins in the summer and fuels metabolism. Tidal transport of the newly produced autochthonous chlorophyll particles from the Bay into the Estuary could also provide a source of labile material to the marshes surrounding the Murderkill, thus perhaps fueling marsh respiration. As a consequence of the tidal coupling between Delaware Bay and the Murderkill Estuary, ecosystem productivity and metabolism in the Bay and Estuary are linked, generating an ecosystem feedback mechanism. Storms modulate this tidally-coupled biogeochemical reactor, by generating significant nitrate and salinity changes. Depending on their magnitude and duration, storms induce large phytoplankton blooms in the Delaware Bay. Such large phytoplankton blooms may occur more often with climate change, since century-long discharge records document an increase in storm frequency.

  13. 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

  14. Small wind turbine performance evaluation using field test data and a coupled aero-electro-mechanical model

    NASA Astrophysics Data System (ADS)

    Wallace, Brian D.

    A series of field tests and theoretical analyses were performed on various wind turbine rotor designs at two Penn State residential-scale wind-electric facilities. This work involved the prediction and experimental measurement of the electrical and aerodynamic performance of three wind turbines; a 3 kW rated Whisper 175, 2.4 kW rated Skystream 3.7, and the Penn State designed Carolus wind turbine. Both the Skystream and Whisper 175 wind turbines are OEM blades which were originally installed at the facilities. The Carolus rotor is a carbon-fiber composite 2-bladed machine, designed and assembled at Penn State, with the intent of replacing the Whisper 175 rotor at the off-grid system. Rotor aerodynamic performance is modeled using WT_Perf, a National Renewable Energy Laboratory developed Blade Element Momentum theory based performance prediction code. Steady-state power curves are predicted by coupling experimentally determined electrical characteristics with the aerodynamic performance of the rotor simulated with WT_Perf. A dynamometer test stand is used to establish the electromechanical efficiencies of the wind-electric system generator. Through the coupling of WT_Perf and dynamometer test results, an aero-electro-mechanical analysis procedure is developed and provides accurate predictions of wind system performance. The analysis of three different wind turbines gives a comprehensive assessment of the capability of the field test facilities and the accuracy of aero-electro-mechanical analysis procedures. Results from this study show that the Carolus and Whisper 175 rotors are running at higher tip-speed ratios than are optimum for power production. The aero-electro-mechanical analysis predicted the high operating tip-speed ratios of the rotors and was accurate at predicting output power for the systems. It is shown that the wind turbines operate at high tip-speeds because of a miss-match between the aerodynamic drive torque and the operating torque of the wind

  15. Small RNAs prevent transcription-coupled loss of histone H3 lysine 9 methylation in Arabidopsis thaliana.

    PubMed

    Enke, Raymond A; Dong, Zhicheng; Bender, Judith

    2011-10-01

    In eukaryotes, histone H3 lysine 9 methylation (H3K9me) mediates silencing of invasive sequences to prevent deleterious consequences including the expression of aberrant gene products and mobilization of transposons. In Arabidopsis thaliana, H3K9me maintained by SUVH histone methyltransferases (MTases) is associated with cytosine methylation (5meC) maintained by the CMT3 cytosine MTase. The SUVHs contain a 5meC binding domain and CMT3 contains an H3K9me binding domain, suggesting that the SUVH/CMT3 pathway involves an amplification loop between H3K9me and 5meC. However, at loci subject to read-through transcription, the stability of the H3K9me/5meC loop requires a mechanism to counteract transcription-coupled loss of H3K9me. Here we use the duplicated PAI genes, which stably maintain SUVH-dependent H3K9me and CMT3-dependent 5meC despite read-through transcription, to show that when PAI sRNAs are depleted by dicer ribonuclease mutations, PAI H3K9me and 5meC levels are reduced and remaining PAI 5meC is destabilized upon inbreeding. The dicer mutations confer weaker reductions in PAI 5meC levels but similar or stronger reductions in PAI H3K9me levels compared to a cmt3 mutation. This comparison indicates a connection between sRNAs and maintenance of H3K9me independent of CMT3 function. The dicer mutations reduce PAI H3K9me and 5meC levels through a distinct mechanism from the known role of dicer-dependent sRNAs in guiding the DRM2 cytosine MTase because the PAI genes maintain H3K9me and 5meC at levels similar to wild type in a drm2 mutant. Our results support a new role for sRNAs in plants to prevent transcription-coupled loss of H3K9me. PMID:22046144

  16. First-principles investigation of the dissociation and coupling of methane on small copper clusters: Interplay of collision dynamics and geometric and electronic effects

    SciTech Connect

    Varghese, Jithin J.; Mushrif, Samir H.

    2015-05-14

    Small metal clusters exhibit unique size and morphology dependent catalytic activity. The search for alternate minimum energy pathways and catalysts to transform methane to more useful chemicals and carbon nanomaterials led us to investigate collision induced dissociation of methane on small Cu clusters. We report here for the first time, the free energy barriers for the collision induced activation, dissociation, and coupling of methane on small Cu clusters (Cu{sub n} where n = 2–12) using ab initio molecular dynamics and metadynamics simulations. The collision induced activation of the stretching and bending vibrations of methane significantly reduces the free energy barrier for its dissociation. Increase in the cluster size reduces the barrier for dissociation of methane due to the corresponding increase in delocalisation of electron density within the cluster, as demonstrated using the electron localisation function topology analysis. This enables higher probability of favourable alignment of the C–H stretching vibration of methane towards regions of high electron density within the cluster and makes higher number of sites available for the chemisorption of CH{sub 3} and H upon dissociation. These characteristics contribute in lowering the barrier for dissociation of methane. Distortion and reorganisation of cluster geometry due to high temperature collision dynamics disturb electron delocalisation within them and increase the barrier for dissociation. Coupling reactions of CH{sub x} (x = 1–3) species and recombination of H with CH{sub x} have free energy barriers significantly lower than complete dehydrogenation of methane to carbon. Thus, competition favours the former reactions at high hydrogen saturation on the clusters.

  17. Challenging Student Behaviour

    ERIC Educational Resources Information Center

    Jones, Glyn; Philp, Clare

    2011-01-01

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

  18. Stretched poly(methyl methacrylate) gel aligns small organic molecules in chloroform. stereochemical analysis and diastereotopic proton NMR assignment in ludartin using residual dipolar couplings and 3J coupling constant analysis.

    PubMed

    Gil, Roberto R; Gayathri, Chakicherla; Tsarevsky, Nicolay V; Matyjaszewski, Krzysztof

    2008-02-01

    Poly(methyl methacrylate) (PMMA) gels prepared by copolymerizing methyl methacrylate (MMA) and various amounts of ethylene glycol dimethacrylate (EGDMA) in the presence of the radical initiator V-70 (2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile)) can orient small organic molecules when swollen in NMR tubes with CDCl(3). The aligning properties of the stretched PMMA gels were evaluated by monitoring the quadrupolar splitting of the (2)H NMR signal of CDCl(3), and the aligning degree is proportional to the cross-linking density. Natural abundance one-bond (1)H-(13)C residual dipolar couplings (RDCs) for menthol measured in the gels depended on the cross-link density. The stereochemistry and assignment of the diastereotopic protons of the gastroprotective and nonsteroidal aromatase inhibitor sesquiterpene lactone ludartin, isolated from Stevia yaconensis var. subeglandulosa, were unambiguously determined using a combination of natural abundance one-bond (1)H-(13)C RDCs measured in a PMMA gel and a (3)J coupling constant analysis. PMID:18177050

  19. Coupling spindle position with mitotic exit in budding yeast: The multifaceted role of the small GTPase Tem1

    PubMed Central

    Scarfone, Ilaria; Piatti, Simonetta

    2015-01-01

    The budding yeast S. cerevisiae divides asymmetrically and is an excellent model system for asymmetric cell division. As for other asymmetrically dividing cells, proper spindle positioning along the mother-daughter polarity axis is crucial for balanced chromosome segregation. Thus, a surveillance mechanism named Spindle Position Checkpoint (SPOC) inhibits mitotic exit and cytokinesis until the mitotic spindle is properly oriented, thereby preventing the generation of cells with aberrant ploidies. The small GTPase Tem1 is required to trigger a Hippo-like protein kinase cascade, named Mitotic Exit Network (MEN), that is essential for mitotic exit and cytokinesis but also contributes to correct spindle alignment in metaphase. Importantly, Tem1 is the target of the SPOC, which relies on the activity of the GTPase-activating complex (GAP) Bub2-Bfa1 to keep Tem1 in the GDP-bound inactive form. Tem1 forms a hetero-trimeric complex with Bub2-Bfa1 at spindle poles (SPBs) that accumulates asymmetrically on the bud-directed spindle pole during mitosis when the spindle is properly positioned. In contrast, the complex remains symmetrically localized on both poles of misaligned spindles. We have recently shown that Tem1 residence at SPBs depends on its nucleotide state and, importantly, asymmetry of the Bub2-Bfa1-Tem1 complex does not promote mitotic exit but rather controls spindle positioning. PMID:26507466

  20. Power-law spectrum and small-world structure emerge from coupled evolution of neuronal activity and synaptic dynamics

    NASA Astrophysics Data System (ADS)

    Zeng, Hong-Li; Zhu, Chen-Ping; Guo, Yan-Dong; Teng, Ao; Jia, Jing; Kong, Hui; Zhou, Rui; Yang, Juan-Ping; Li, Su-Quan

    2015-04-01

    A co-evolutionary neuronal network model based on previous ones is proposed, and both functional and structural properties are numerically calculated. Recent experiments have revealed power-law behavior in electrocorticogram (ECoG) spectrum related with synaptic plasticity and reorganization. In the present neuronal network model, the network starts its evolution from the initial configuration of random network which is the least biased and without special structure, and the interaction rules among neurons are modified from both models by Bornholdt's and Arcangelis' groups to simulate the process of synaptic development and maturation. The system exhibits dynamic small-world structure which is the result of evolution instead of the assumption beforehand. Meanwhile, the power spectrum of electrical signals reproduces the power-law behavior with the exponent 2.0 just as what is experimentally measured in ECoG spectrum. Moreover, the power spectrum of the average degree per neuron over time also exhibits power-law behavior, with the exponent 2.0 again over more than 5 orders of magnitude. Different from previous results, our network exhibits assortative degree-degree correlation which is expected to be checked by experiments.

  1. Creep deformation behavior of Sn-3.5Ag solder/Cu couple at small length scales

    SciTech Connect

    Kerr, M.; Chawla, N

    2004-09-06

    In order to adequately characterize the behavior of solder balls in electronic devices, the mechanical behavior of solder joints needs to be studied at small length scales. The creep behavior of single solder ball Sn-Ag/Cu solder joints was studied in shear, at 25, 60, 95, and 130 deg. C, using a microforce testing system. A change in the creep stress exponent with increasing stress was observed and explained in terms of a threshold stress for bypass of Ag{sub 3}Sn particles by dislocations. The stress exponent was also temperature dependent, exhibiting an increase in exponent of two from lower to higher temperature. The activation energy for creep was found to be temperature dependant, correlating with self-diffusion of pure Sn at high temperatures, and dislocation core diffusion of pure Sn at lower temperatures. Normalizing the creep rate for activation energy and the temperature-dependence of shear modulus allowed for unification of the creep data. Microstructure characterization, including preliminary TEM analysis, and fractographic analysis were conducted in order to fully describe the creep behavior of the material.

  2. Small angle X-ray scattering coupled with in situ electromechanical probing of nanoparticle-based resistive strain gauges.

    PubMed

    Decorde, Nicolas; Sangeetha, Neralagatta M; Viallet, Benoit; Viau, Guillaume; Grisolia, Jérémie; Coati, Alessandro; Vlad, Alina; Garreau, Yves; Ressier, Laurence

    2014-12-21

    A comprehensive study on the electromechanical behavior of nanoparticle-based resistive strain gauges in action through normal and grazing incidence small angle X-ray scattering (SAXS/GISAXS) investigations is presented. The strain gauges were fabricated from arrays of colloidal gold nanoparticle (NP) wires assembled on flexible polyethylene terephthalate and polyimide substrates by convective self-assembly. Microstructural changes (mean interparticle distance variations) within these NP wires under uniaxial stretching estimated by SAXS/GISAXS are correlated to their macroscopic electrical resistance variations. SAXS measurements suggest a linear longitudinal extension and transversal contraction of the NP wires with applied strain (0 to ∼ 13%). The slope of this longitudinal variation is less than unity, implying a partial strain transfer from the substrate to the NP wires. The simultaneously measured electrical resistance of the strain gauges shows an exponential variation within the elastic domain of the substrate deformation, consistent with electron tunnelling through the interparticle gaps. A slower variation observed within the plastic domain suggests the formation of new electronic conduction pathways. Implications of transversal contraction of the NP wires on the directional sensitivities of strain gauges are evaluated by simulating electronic conduction in models mimicking a realistic NP arrangement. A loss of directionality of the NP-based strain gauges due to transversal current flow within the NP wires is deduced. PMID:25371292

  3. Small angle X-ray scattering coupled with in situ electromechanical probing of nanoparticle-based resistive strain gauges

    NASA Astrophysics Data System (ADS)

    Decorde, Nicolas; Sangeetha, Neralagatta M.; Viallet, Benoit; Viau, Guillaume; Grisolia, Jérémie; Coati, Alessandro; Vlad, Alina; Garreau, Yves; Ressier, Laurence

    2014-11-01

    A comprehensive study on the electromechanical behavior of nanoparticle-based resistive strain gauges in action through normal and grazing incidence small angle X-ray scattering (SAXS/GISAXS) investigations is presented. The strain gauges were fabricated from arrays of colloidal gold nanoparticle (NP) wires assembled on flexible polyethylene terephthalate and polyimide substrates by convective self-assembly. Microstructural changes (mean interparticle distance variations) within these NP wires under uniaxial stretching estimated by SAXS/GISAXS are correlated to their macroscopic electrical resistance variations. SAXS measurements suggest a linear longitudinal extension and transversal contraction of the NP wires with applied strain (0 to ~13%). The slope of this longitudinal variation is less than unity, implying a partial strain transfer from the substrate to the NP wires. The simultaneously measured electrical resistance of the strain gauges shows an exponential variation within the elastic domain of the substrate deformation, consistent with electron tunnelling through the interparticle gaps. A slower variation observed within the plastic domain suggests the formation of new electronic conduction pathways. Implications of transversal contraction of the NP wires on the directional sensitivities of strain gauges are evaluated by simulating electronic conduction in models mimicking a realistic NP arrangement. A loss of directionality of the NP-based strain gauges due to transversal current flow within the NP wires is deduced.A comprehensive study on the electromechanical behavior of nanoparticle-based resistive strain gauges in action through normal and grazing incidence small angle X-ray scattering (SAXS/GISAXS) investigations is presented. The strain gauges were fabricated from arrays of colloidal gold nanoparticle (NP) wires assembled on flexible polyethylene terephthalate and polyimide substrates by convective self-assembly. Microstructural changes (mean

  4. 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

  5. In situ location and U-Pb dating of small zircon grains in igneous rocks using laser ablation-inductively coupled plasma-quadrupole mass spectrometry

    NASA Astrophysics Data System (ADS)

    Sack, Patrick J.; Berry, Ron F.; Meffre, Sebastien; Falloon, Trevor J.; Gemmell, J. Bruce; Friedman, Richard M.

    2011-05-01

    A new U-Pb zircon dating protocol for small (10-50 μm) zircons has been developed using an automated searching method to locate zircon grains in a polished rock mount. The scanning electron microscope-energy-dispersive X ray spectrum-based automated searching method can routinely find in situ zircon grains larger than 5 μm across. A selection of these grains was ablated using a 10 μm laser spot and analyzed in an inductively coupled plasma-quadrupole mass spectrometer (ICP-QMS). The technique has lower precision (˜6% uncertainty at 95% confidence on individual spot analyses) than typical laser ablation ICP-MS (˜2%), secondary ion mass spectrometry (<1%), and isotope dilution-thermal ionization mass spectrometry (˜0.4%) methods. However, it is accurate and has been used successfully on fine-grained lithologies, including mafic rocks from island arcs, ocean basins, and ophiolites, which have traditionally been considered devoid of dateable zircons. This technique is particularly well suited for medium- to fine-grained mafic volcanic rocks where zircon separation is challenging and can also be used to date rocks where only small amounts of sample are available (clasts, xenoliths, dredge rocks). The most significant problem with dating small in situ zircon grains is Pb loss. In our study, many of the small zircons analyzed have high U contents, and the isotopic compositions of these grains are consistent with Pb loss resulting from internal α radiation damage. This problem is not significant in very young rocks and can be minimized in older rocks by avoiding high-U zircon grains.

  6. Communication: dynamical embedding: correct quantum response from coupling TDDFT for a small cluster with classical near-field electrodynamics for an extended region.

    PubMed

    Gao, Yi; Neuhauser, Daniel

    2013-05-14

    We show how to obtain the correct electronic response of a large system by embedding; a small region is propagated by TDDFT (time-dependent density functional theory) simultaneously with a classical electrodynamics evolution using the Near-Field method over a larger external region. The propagations are coupled through a combined time-dependent density yielding a common Coulomb potential. We show that the embedding correctly describes the plasmonic response of a Mg(0001) slab and its influence on the dynamical charge transfer between an adsorbed H2O molecule and the substrate, giving the same spectral shape as full TDDFT (similar plasmon peak and molecular-dependent differential spectra) with much less computational effort. The results demonstrate that atomistic embedding electrodynamics is promising for nanoplasmonics and nanopolaritonics. PMID:23676021

  7. Communication: Dynamical embedding: Correct quantum response from coupling TDDFT for a small cluster with classical near-field electrodynamics for an extended region

    SciTech Connect

    Gao Yi; Neuhauser, Daniel

    2013-05-14

    We show how to obtain the correct electronic response of a large system by embedding; a small region is propagated by TDDFT (time-dependent density functional theory) simultaneously with a classical electrodynamics evolution using the Near-Field method over a larger external region. The propagations are coupled through a combined time-dependent density yielding a common Coulomb potential. We show that the embedding correctly describes the plasmonic response of a Mg(0001) slab and its influence on the dynamical charge transfer between an adsorbed H{sub 2}O molecule and the substrate, giving the same spectral shape as full TDDFT (similar plasmon peak and molecular-dependent differential spectra) with much less computational effort. The results demonstrate that atomistic embedding electrodynamics is promising for nanoplasmonics and nanopolaritonics.

  8. Coupling Specificity of NOP Opioid Receptors to Pertussis-Toxin-Sensitive Gα Proteins in Adult Rat Stellate Ganglion Neurons Using Small Interference RNA

    PubMed Central

    Margas, Wojciech; Sedeek, Khaled; Ruiz-Velasco, Victor

    2008-01-01

    The opioid receptor-like 1 (NOP or ORL1) receptor is a G-protein-coupled receptor the endogenous ligand of which is the heptadecapeptide, nociceptin (Noc). NOP receptors are known to modulate pain processing at spinal, supraspinal, and peripheral levels. Previous work has demonstrated that NOP receptors inhibit N-type Ca2+ channel currents in rat sympathetic stellate ganglion (SG) neurons via pertussis toxin (PTX)-sensitive Gαi/o subunits. However, the identification of the specific Gα subunit that mediates the Ca2+ current modulation is unknown. The purpose of the present study was to examine coupling specificity of Noc-activated NOP receptors to N-type Ca2+ channels in SG neurons. Small interference RNA (siRNA) transfection was employed to block the expression of PTX-sensitive Gα subunits. RT-PCR results showed that siRNA specifically decreased the expression of the intended Gα subunit. Evaluation of cell surface protein expression and Ca2+ channel modulation were assessed by immunofluorescence staining and electrophysiological recordings, respectively. Furthermore, the presence of mRNA of the intended siRNA target Gα protein was examined by RT-PCR experiments. Fluorescence imaging showed that Gαi1, Gαi3, and Gαo were expressed in SG neurons. The transfection of Gαi1-specific siRNA resulted in a significant decrease in Noc-mediated Ca2+ current inhibition, while silencing of either Gαi3 or Gαo was without effect. Taken together, these results suggest that in SG neurons Gαi1 subunits selectively couple NOP receptors to N-type Ca2+ channels. PMID:18562551

  9. Expression of G protein-coupled receptor 56 is associated with tumor progression in non-small-cell lung carcinoma patients

    PubMed Central

    Song, Yanjie; Li, Aiqin; Zhang, Li; Duan, Lingling

    2016-01-01

    Background G protein-coupled receptor 56 (GPR56) is an adhesion G protein-coupled receptor with essential functions for cell physiology and survival, and its expression correlates with prognosis in a number of malignancies. The aim of this study is to determine the relationship of GPR56 expression with clinicopathological parameters and prognosis in non-small-cell lung carcinoma (NSCLC). Methods The levels of GPR56 were evaluated by immunohistochemistry in 157 NSCLC tissue samples. The association between GPR56 and clinicopathological parameters was evaluated by χ2 test. Univariate and multivariate analyses were performed to demonstrate the prognosis role of GPR56. The function of GPR56 in NSCLC cell lines was also explored through overexpression and knockdown studies. Results The expression level of GPR56 in tumor tissues was significantly correlated with the TNM stage of NSCLC (P=0.005). Univariate and multivariate analyses revealed that GPR56 can act as an independent prognostic factor for overall survival. Furthermore, through overexpression and knockdown experiments, we confirmed that GPR56 can promote the proliferation and invasion of NSCLC cells. Conclusion GPR56 plays an important role in tumor development and may serve as a promising target for prognostic prediction in NSCLC. PMID:27462165

  10. Theoretical Investigation of Small Polyatomic Ions Observed in Inductively Coupled Plasma Mass Spectrometry: HxCO+ and HxN2+ (x = 1, 2, 3)

    SciTech Connect

    Sears, K.; Ferguson, J.; Dudley, T.; Houk, R.; Gordon, M.

    2008-03-01

    Two series of small polyatomic ions, H{sub x}CO{sup +} and H{sub x}N{sub 2}{sup +} (x = 1, 2, 3), were systematically characterized using three correlated theoretical techniques: density functional theory using the B3LYP functional, spin-restricted second-order perturbation theory, and singles + doubles coupled cluster theory with perturbative triples. On the basis of thermodynamic data, the existence of these ions in inductively coupled plasma mass spectrometry (ICP-MS) experiments is not surprising since the ions are predicted to be considerably more stable than their corresponding dissociation products (by 30-170 kcal/mol). While each pair of isoelectronic ions exhibit very similar thermodynamic and kinetic characteristics, there are significant differences within each series. While the mechanism for dissociation of the larger ions occurs through hydrogen abstraction, the triatomic ions (HCO{sup +} and HN{sub 2}{sup +}) appear to dissociate by proton abstraction. These differing mechanisms help to explain large differences in the abundances of HN{sub 2}{sup +} and HCO{sup +} observed in ICP-MS experiments.

  11. Structure-Function Analyses of the Interactions between Rab11 and Rab14 Small GTPases with Their Shared Effector Rab Coupling Protein (RCP)*

    PubMed Central

    Lall, Patrick; Lindsay, Andrew J.; Hanscom, Sara; Kecman, Tea; Taglauer, Elizabeth S.; McVeigh, Una M.; Franklin, Edward; McCaffrey, Mary W.; Khan, Amir R.

    2015-01-01

    Rab GTPases recruit effector proteins, via their GTP-dependent switch regions, to distinct subcellular compartments. Rab11 and Rab25 are closely related small GTPases that bind to common effectors termed the Rab11 family of interacting proteins (FIPs). The FIPs are organized into two subclasses (class I and class II) based on sequence and domain organization, and both subclasses contain a highly conserved Rab-binding domain at their C termini. Yeast two-hybrid and biochemical studies have revealed that the more distantly related Rab14 also interacts with class I FIPs. Here, we perform detailed structural, thermodynamic, and cellular analyses of the interactions between Rab14 and one of the class I FIPs, the Rab-coupling protein (RCP), to clarify the molecular aspects of the interaction. We find that Rab14 indeed binds to RCP, albeit with reduced affinity relative to conventional Rab11-FIP and Rab25-FIP complexes. However, in vivo, Rab11 recruits RCP onto biological membranes. Furthermore, biophysical analyses reveal a noncanonical 1:2 stoichiometry between Rab14-RCP in dilute solutions, in contrast to Rab11/25 complexes. The structure of Rab14-RCP reveals that Rab14 interacts with the canonical Rab-binding domain and also provides insight into the unusual properties of the complex. Finally, we show that both the Rab coupling protein and Rab14 function in neuritogenesis. PMID:26032412

  12. Structure-Function Analyses of the Interactions between Rab11 and Rab14 Small GTPases with Their Shared Effector Rab Coupling Protein (RCP).

    PubMed

    Lall, Patrick; Lindsay, Andrew J; Hanscom, Sara; Kecman, Tea; Taglauer, Elizabeth S; McVeigh, Una M; Franklin, Edward; McCaffrey, Mary W; Khan, Amir R

    2015-07-24

    Rab GTPases recruit effector proteins, via their GTP-dependent switch regions, to distinct subcellular compartments. Rab11 and Rab25 are closely related small GTPases that bind to common effectors termed the Rab11 family of interacting proteins (FIPs). The FIPs are organized into two subclasses (class I and class II) based on sequence and domain organization, and both subclasses contain a highly conserved Rab-binding domain at their C termini. Yeast two-hybrid and biochemical studies have revealed that the more distantly related Rab14 also interacts with class I FIPs. Here, we perform detailed structural, thermodynamic, and cellular analyses of the interactions between Rab14 and one of the class I FIPs, the Rab-coupling protein (RCP), to clarify the molecular aspects of the interaction. We find that Rab14 indeed binds to RCP, albeit with reduced affinity relative to conventional Rab11-FIP and Rab25-FIP complexes. However, in vivo, Rab11 recruits RCP onto biological membranes. Furthermore, biophysical analyses reveal a noncanonical 1:2 stoichiometry between Rab14-RCP in dilute solutions, in contrast to Rab11/25 complexes. The structure of Rab14-RCP reveals that Rab14 interacts with the canonical Rab-binding domain and also provides insight into the unusual properties of the complex. Finally, we show that both the Rab coupling protein and Rab14 function in neuritogenesis. PMID:26032412

  13. Applicability of the Joule-Thomson Cryocooler Coupled with Membrane-Based Purification System for Liquefaction of Natural Gas in Small Quantities

    NASA Astrophysics Data System (ADS)

    Piotrowska, A.; Chorowski, M.

    2008-03-01

    Joule-Thomson (J-T) cryocoolers using gas mixture have been studied theoretically and experimentally for a variety of applications. Gas separation technology using polymer membrane is emerging. In this paper the concept of coupling the J-T cooler with a hollow fiber membranes is presented. The apparatus can be used in many applications, like compressed natural gas (CNG) purification and condensation into LNG or separation and liquefaction of nitrogen from air. The paper describes the system and experimental dependence of the separated nitrogen purity on the membrane inlet air pressure. The Second Law of Thermodynamics is used to optimize the composition of the mixture for natural gas cooling and liquefaction. Possible applications of the system depend on membrane material. Membranes used in separation of N2/air or CO2/CH4 are now commercially available [2,6]. The combination of the J-T cooler with N2/air membrane enables the construction of the liquid nitrogen production system aimed at cryosurgical applications. Similarly, J-T cooler coupled with CO2/CH4 membrane can be used for purification and liquefaction of natural gas in small quantities e.g. satisfying future car refueling system needs.

  14. 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.

  15. Predicting electrical and thermal abuse behaviours of practical lithium-ion cells from accelerating rate calorimeter studies on small samples in electrolyte

    NASA Astrophysics Data System (ADS)

    Richard, M. N.; Dahn, J. R.

    An accelerating rate calorimeter (ARC) is used to measure the thermal stability of de-intercalated Li 1+ xMn 2- xO 4 in LiPF 6 EC:DEC (33:67) electrolyte. Self-heating is detected well after the 80°C onset of self-heating measured for lithium intercalated mesocarbon microbead (MCMB) electrodes in LiPF 6 EC:DEC (33:67) electrolyte. As a result, the initial self-heating measured in a practical carbon/Li 1+ xMn 2- xO 4 lithium-ion cell is caused by reactions at the anode. In previous work, we have proposed a model for the reactions that cause self-heating in MCMB electrodes in electrolyte. By assuming that a cell self-heats only because reactions occur at the anode, the model can be used to predict the power generated by the amount of MCMB in practical cells with an inert cathode. The calculated chemically generated power can be combined with power loss measurements, due to the transfer of heat to the environment, to predict the short-circuit behaviour and the oven exposure behaviour for a cell containing an MCMB anode and an inert cathode. The results agree qualitatively with short-circuit and oven exposure results measured on NEC Moli energy 18650 cells containing an Li 1+ xMn 2- xO 4 cathode.

  16. Weight loss is coupled with improvements to affective state in obese participants engaged in behavior change therapy based on incremental, self-selected "small changes".

    PubMed

    Paxman, Jenny R; Hall, Anna C; Harden, Charlotte J; O'Keeffe, Jean; Simper, Trevor N

    2011-05-01

    The aim of this study was to investigate the effects of a group behavior change intervention involving self-selected, contextualized, and mediated goal setting on anthropometric, affective, and dietary markers of health. It was hypothesized that the intervention would elicit changes consistent with accepted health recommendations for obese individuals. A rolling program of 12-week "Small Changes" interventions during 24 months recruited 71 participants; each program accommodated 10 to 13 adults (body mass index [BMI] ≥ 30 kg/m²). Fifty-eight participants completed Small Changes. Repeated measures were made at baseline, 6 and 12 weeks. Anthropometric measures included height and weight (to calculate BMI), body composition, waist circumference, and blood pressure. Affective state was monitored using relevant validated questionnaires. Dietary assessment used 3-day household measures food diaries with Schofield equations to monitor underreporting. Relevant blood measures were recorded throughout. Across the measurement period, Small Changes elicited a significant reduction in body weight (baseline, 102.95 ± 15.47 vs 12 weeks 100.09 ± 16.01 kg, P < .0005), coupled with associated significant improvements in BMI, body fat percentage, and waist circumference measures. There were additional significant positive changes in measures of affective state including general well-being (baseline, 58.92 ± 21.22 vs 12 weeks 78.04 ± 14.60, P < .0005) and total mood disturbance (baseline, 31.19 ± 34.03 vs 12 weeks 2.67 ± 24.96, P < .0005). Dietary changes that occurred were largely consistent with evidenced-based recommendations for weight management and included significant reductions in total energy intake and in fat and saturated fat as a proportion of energy. The Small Changes approach can elicit a range of health-orientated benefits for obese participants, and although further work is needed to ascertain the longevity of such effects, the outcomes from Small Changes are

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

    NASA Astrophysics Data System (ADS)

    Small, Michael

    2015-12-01

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

  18. Small protein biomarkers of culture in Bacillus spores detected using capillary liquid chromatography coupled with matrix assisted laser desorption/ionization mass spectrometry.

    PubMed

    Wunschel, David; Wahl, Jon; Willse, Alan; Valentine, Nancy; Wahl, Karen

    2006-10-20

    Capillary liquid chromatography (cLC) coupled with matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry (TOF-MS) was used to compare small proteins and peptides extracted from Bacillus subtilis spores grown on four different media. A single, efficient protein separation, compatible with MALDI-MS analysis, was employed to reduce competitive ionization between proteins, and thus interrogate more proteins than possible using direct MALDI-MS. The MALDI-MS data files for each fraction are assembled as two-dimensional data sets of retention time and mass information. This method of visualizing small protein data required careful attention to background correction as well as mass and retention time variability. The resulting data sets were used to create comparative displays of differences in protein profiles between different spore preparations. Protein differences were found between two different solid media in both phase bright and phase dark spore phenotype. The protein differences between two different liquid media were also examined. As an extension of this method, we have demonstrated that candidate protein biomarkers can be trypsin digested to provide identifying peptide fragment information following the cLC-MALDI experiment. We have demonstrated this method on two markers and utilized acid breakdown information to identify one additional marker for this organism. The resulting method can be used to identify discriminating proteins as potential biomarkers of growth media, which might ultimately be used for source attribution. PMID:16798120

  19. Multisource Synergistic Electrocatalytic Oxidation Effect of Strongly Coupled PdM (M = Sn, Pb)/N-doped Graphene Nanocomposite on Small Organic Molecules

    PubMed Central

    Wu, Peng; Huang, Yiyin; Kang, Longtian; Wu, Maoxiang; Wang, Yaobing

    2015-01-01

    A series of palladium-based catalysts of metal alloying (Sn, Pb) and/or (N-doped) graphene support with regular enhanced electrocatalytic activity were investigated. The peak current density (118.05 mA cm−2) of PdSn/NG is higher than the sum current density (45.63 + 47.59 mA cm−2) of Pd/NG and PdSn/G. It reveals a synergistic electrocatalytic oxidation effect in PdSn/N-doped graphene Nanocomposite. Extend experiments show this multisource synergetic catalytic effect of metal alloying and N-doped graphene support in one catalyst on small organic molecule (methanol, ethanol and Ethylene glycol) oxidation is universal in PdM(M = Sn, Pb)/NG catalysts. Further, The high dispersion of small nanoparticles, the altered electron structure and Pd(0)/Pd(II) ratio of Pd in catalysts induced by strong coupled the metal alloying and N-doped graphene are responsible for the multisource synergistic catalytic effect in PdM(M = Sn, Pb) /NG catalysts. Finally, the catalytic durability and stability are also greatly improved. PMID:26434949

  20. Coupling of background reduction with rolling circle amplification for highly sensitive protein detection via terminal protection of small molecule-linked DNA.

    PubMed

    Wang, Qiong; Jiang, Bingying; Xie, Jiaqing; Xiang, Yun; Yuan, Ruo; Chai, Yaqin

    2013-10-01

    In this work, by coupling background current reduction with rolling circle amplification (RCA), we describe the development of an ultrasensitive electrochemical sensing method for protein detection based on a small molecule-linked DNA terminal protection strategy. Our detection platform employs a typical streptavidin (STV)-biotin interaction system. Biotin-linked single-stranded DNA (SH-ssDNA-biotin) is self-assembled on a gold electrode to capture the target protein, STV. The binding of STV with the biotin small molecule recognition element protects the SH-ssDNA-biotin against hydrolysis by exonuclease I (Exo I), while the unbound SH-ssDNA-biotin is effectively hydrolyzed and removed from the electrode surface. The bound STV further interacts with long, RCA-amplified biotin DNAs to facilitate the adsorption of numerous electroactive reporters, hexaammineruthenium(III) chloride (RuHex) via electrostatic interactions, which results in significantly amplified signals for the quantitative determination of STV. Moreover, the removal of the unbound SH-ssDNA-biotin probes from the sensing electrode obviates the accumulation of RuHex and leads to a highly minimized background current. The simultaneous RCA signal amplification and background current reduction is expected to significantly enhance the signal-to-noise ratio and to achieve ultrahigh sensitivity. The results reveal that the developed strategy provides a low detection limit of 0.4 pM with high selectivity. PMID:23907287

  1. Multisource Synergistic Electrocatalytic Oxidation Effect of Strongly Coupled PdM (M = Sn, Pb)/N-doped Graphene Nanocomposite on Small Organic Molecules

    NASA Astrophysics Data System (ADS)

    Wu, Peng; Huang, Yiyin; Kang, Longtian; Wu, Maoxiang; Wang, Yaobing

    2015-10-01

    A series of palladium-based catalysts of metal alloying (Sn, Pb) and/or (N-doped) graphene support with regular enhanced electrocatalytic activity were investigated. The peak current density (118.05 mA cm-2) of PdSn/NG is higher than the sum current density (45.63 + 47.59 mA cm-2) of Pd/NG and PdSn/G. It reveals a synergistic electrocatalytic oxidation effect in PdSn/N-doped graphene Nanocomposite. Extend experiments show this multisource synergetic catalytic effect of metal alloying and N-doped graphene support in one catalyst on small organic molecule (methanol, ethanol and Ethylene glycol) oxidation is universal in PdM(M = Sn, Pb)/NG catalysts. Further, The high dispersion of small nanoparticles, the altered electron structure and Pd(0)/Pd(II) ratio of Pd in catalysts induced by strong coupled the metal alloying and N-doped graphene are responsible for the multisource synergistic catalytic effect in PdM(M = Sn, Pb) /NG catalysts. Finally, the catalytic durability and stability are also greatly improved.

  2. Small protein biomarkers of culture in Bacillus spores detected using capillary liquid chromatography coupled with matrix assisted laser desorption/ionization mass spectrometry

    SciTech Connect

    Wunschel, David S.; Wahl, Jon H.; Willse, Alan R.; Valentine, Nancy B.; Wahl, Karen L.

    2006-10-20

    Capillary liquid chromatography (cLC) coupled with matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry (TOF-MS) was used to compare small proteins and peptides extracted from Bacillus subtilis spores grown on four different media. A single, efficient protein separation, compatible with MALDI-MS analysis, was employed to reduce competitive ionization between proteins, and thus interrogate more proteins than possible using direct MALDI-MS. The MALDI-MS data files for each fraction are assembled as two dimensional data sets of retention time and mass information. This method of visualizing small protein data required careful attention to background correction as well as mass and retention time variability. The resulting data sets were used to create comparative displays of differences in protein profiles between different spore preparations. Protein differences were found between two different solid media in both phase bright and phase dark conditions. The protein differences between two different liquid media were also examined. As an extension of this method, we have demonstrated that candidate protein biomarkers can be trypsin digested to provide identifying peptide fragment information following the cLC-MALDI experiment. We have demonstrated this method on two markers and utilized acid breakdown information to identify one additional marker for this organism. The resulting method can be used to identify discriminating proteins as potential biomarkers of growth media, which might ultimately be used for source attribution.

  3. Coupling the 3D hydro-morphodynamic model Telemac-3D-sisyphe and seismic measurements to estimate bedload transport rates in a small gravel-bed river.

    NASA Astrophysics Data System (ADS)

    Hostache, Renaud; Krein, Andreas; Barrière, Julien

    2014-05-01

    Coupling the 3D hydro-morphodynamic model Telemac-3D-sisyphe and seismic measurements to estimate bedload transport rates in a small gravel-bed river. Renaud Hostache, Andreas Krein, Julien Barrière During flood events, amounts of river bed material are transported via bedload. This causes problems, like the silting of reservoirs or the disturbance of biological habitats. Some current bedload measuring techniques have limited possibilities for studies in high temporal resolutions. Optical systems are usually not applicable because of high turbidity due to concentrated suspended sediment transported. Sediment traps or bedload samplers yield only summative information on bedload transport with low temporal resolution. An alternative bedload measuring technique is the use of seismological systems installed next to the rivers. The potential advantages are observations in real time and under undisturbed conditions. The study area is a 120 m long reach of River Colpach (21.5 km2), a small gravel bed river in Northern Luxembourg. A combined approach of hydro-climatological observations, hydraulic measurements, sediment sampling, and seismological measurements is used in order to investigate bedload transport phenomena. Information derived from seismic measurements and results from a 3-dimensional hydro-morphodynamic model are exemplarily discussed for a November 2013 flood event. The 3-dimensional hydro-morphodynamic model is based on the Telemac hydroinformatic system. This allows for dynamically coupling a 3D hydrodynamic model (Telemac-3D) and a morphodynamic model (Sisyphe). The coupling is dynamic as these models exchange their information during simulations. This is a main advantage as it allows for taking into account the effects of the morphologic changes of the riverbed on the water hydrodynamic and the bedload processes. The coupled model has been calibrated using time series of gauged water depths and time series of bed material collected sequentially (after

  4. 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

  5. Overexpression of G protein-coupled receptor 87 correlates with poorer tumor differentiation and higher tumor proliferation in non-small-cell lung cancer

    PubMed Central

    NII, KAZUHITO; TOKUNAGA, YOSHIMASA; LIU, DAGE; ZHANG, XIA; NAKANO, JUN; ISHIKAWA, SHINYA; KAKEHI, YOSHIYUKI; HABA, REIJI; YOKOMISE, HIROYASU

    2014-01-01

    G protein-coupled receptor 87 (GPR87) is a newly deorphanized member of the transmembrane G protein-coupled receptor family. Recently, GPR87 was suggested to contribute to the viability of human tumor cells and overexpression of GPR87 mRNA was detected in a number of malignant tumors, including lung cancer. We performed a retrospective study of GPR87 expression in association with clinical characteristics and biological markers in non-small-cell lung cancer (NSCLC). We investigated a total of 123 patients with NSCLC who underwent surgery between 1999 and 2004 (58 adenocarcinomas, 53 squamous cell carcinomas and 12 others). Immunohistochemistry was used to evaluate the intratumoral expression of GPR87 and the Ki-67 proliferation index. The TUNEL method was also used to investigate tumor apoptosis. A total of 63 tumors (51.2%) were found to be GPR87-positive. These tumors were more frequently encountered among squamous cell carcinomas rather than among adenocarcinomas (62.3 vs. 43.1%, respectively; P=0.044) and were significantly more frequently poorly and moderately differentiated rather than well differentiated (P=0.029). Moreover, the Ki-67 index was significantly higher in GPR87-positive compared to GPR87-negative tumors (57.0 vs. 40.0%, respectively; P=0.002). The overall survival was significantly worse for patients with GPR87-positive compared to those with GPR87-negative tumors (P=0.029). The Cox regression analyses also demonstrated that the GPR87 status was a significant prognostic factor for NSCLC patients [hazard ratio=2.053; P=0.018). The present study demonstrated that in NSCLC, the overexpression of GPR87 is significantly associated with poorer differentiation and higher proliferation. During the progression of NSCLC, GPR87 overexpression may be associated with the acquisition of a more aggressive phenotype and, therefore, is a potentially useful target for prognostication and treatment. PMID:24940491

  6. Flight destinations and foraging behaviour of northern gannets ( Sula bassana) preying on a small forage fish in a low-Arctic ecosystem

    NASA Astrophysics Data System (ADS)

    Garthe, Stefan; Montevecchi, William A.; Davoren, Gail K.

    2007-02-01

    We applied data loggers (temperature-depth and GPS-temperature-depth) on individual birds in combination with dietary sampling and a vessel survey of prey availability to assess the foraging behaviour of northern gannets ( Sula bassana, Linnaeus 1758) in a low-Arctic ecosystem in the NW Atlantic. We demonstrate that the gannets foraged almost exclusively on inshore and coastal aggregations of capelin. There was a strong correspondence between the distributions of capelin and foraging gannets, and gannets exhibited persistence in successive foraging trips to the same foraging areas. The diving activity of gannets was highest during the early morning and evening, when capelin are known to be primarily available in the upper water column. Most of the gannets dive depths were less than 5 m. Flight speeds recorded by GPS were 9% higher than those estimated by previous methods and were shown to benefit from tail wind. This study shows how a combination of ship-based surveys and individually tagged birds can help understanding predator-prey intersection in a three-dimensional space in the marine environment.

  7. Behavioural and Cognitive-Behavioural Treatments of Parasomnias

    PubMed Central

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

    2015-01-01

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

  8. Domain Movements upon Activation of Phenylalanine Hydroxylase Characterized by Crystallography and Chromatography-Coupled Small-Angle X-ray Scattering.

    PubMed

    Meisburger, Steve P; Taylor, Alexander B; Khan, Crystal A; Zhang, Shengnan; Fitzpatrick, Paul F; Ando, Nozomi

    2016-05-25

    Mammalian phenylalanine hydroxylase (PheH) is an allosteric enzyme that catalyzes the first step in the catabolism of the amino acid phenylalanine. Following allosteric activation by high phenylalanine levels, the enzyme catalyzes the pterin-dependent conversion of phenylalanine to tyrosine. Inability to control elevated phenylalanine levels in the blood leads to increased risk of mental disabilities commonly associated with the inherited metabolic disorder, phenylketonuria. Although extensively studied, structural changes associated with allosteric activation in mammalian PheH have been elusive. Here, we examine the complex allosteric mechanisms of rat PheH using X-ray crystallography, isothermal titration calorimetry (ITC), and small-angle X-ray scattering (SAXS). We describe crystal structures of the preactivated state of the PheH tetramer depicting the regulatory domains docked against the catalytic domains and preventing substrate binding. Using SAXS, we further describe the domain movements involved in allosteric activation of PheH in solution and present the first demonstration of chromatography-coupled SAXS with Evolving Factor Analysis (EFA), a powerful method for separating scattering components in a model-independent way. Together, these results support a model for allostery in PheH in which phenylalanine stabilizes the dimerization of the regulatory domains and exposes the active site for substrate binding and other structural changes needed for activity. PMID:27145334

  9. Development of double-layer coupled coil for improving S/N in 7 T small-animal MRI.

    PubMed

    Kim, Kyoung-Nam; Seo, Jeung-Hoon; Han, Sang-Doc; Heo, Phil; Im, Geun Ho; Lee, Jung Hee

    2015-01-01

    The purpose of this study was to develop a new double-layer coupled (DLC) surface radiofrequency (RF) coil using a combination of single-layer planar (SLP) and single-layer circular (SLC) coils, for enhancement of magnetic flux (B1 ) sensitivity and RF penetration in 7 T rat-body magnetic resonance imaging (MRI). The proposed DLC surface coil was fabricated according to an electromagnetic (EM) simulation and validated based on the B1 distribution and bench measurements. The DLC coil performance was quantitatively evaluated based on the signal-to-noise ratio (S/N) and coil-response signal intensity curves in phantom and in vivo rat-body images. In the computational EM calculation and 7 T in vivo experimental results, the DLC surface coil clearly showed an increased S/N and higher RF transmit (B1 (+) ) profiles, compared to those of the SLP and SLC coils. While all surface coils displayed a rapid decrease in the MR signal from the near-coil region to the subject, the results reveal that the DLC coil concept may be used to provide sufficient RF penetration and high S/N and degrees of freedom for use in partial body imaging for 7 T ultra-high-field small-animal MRI. PMID:25914270

  10. Discovery and Characterization of a Novel Small-Molecule Agonist for Medium-Chain Free Fatty Acid Receptor G Protein-Coupled Receptor 84.

    PubMed

    Zhang, Qing; Yang, Hui; Li, Jing; Xie, Xin

    2016-05-01

    G protein-coupled receptor 84 (GPR84) is a free fatty acid receptor activated by medium-chain free fatty acids with 9-14 carbons. It is expressed mainly in the immune-related tissues, such as spleen, bone marrow, and peripheral blood leukocytes. GPR84 plays significant roles in inflammatory processes and may represent a novel drug target for the treatment of immune-mediated diseases. However, the lack of potent and specific ligands for GPR84 hindered the study of its functions and the development of potential clinical applications. Here, we report the screen of 160,000 small-molecule compounds with a calcium mobilization assay using a human embryonic kidney 293 cell line stably expressing GPR84 and Gα16, and the identification of 2-(hexylthio)pyrimidine-4,6-diol (ZQ-16) as a potent and selective agonist of GPR84 with a novel structure. ZQ-16 activates several GPR84-mediated signaling pathways, including calcium mobilization, inhibition of cAMP accumulation, phosphorylation of extracellular signal-regulated protein kinase 1/2, receptor desensitization and internalization, and receptor-β-arrestin interaction. This compound may be a useful tool to study the functions of GPR84 and a potential candidate for further structural optimization. PMID:26962172

  11. Gold Nanoparticle Internal Structure and Symmetry Probed by Unified Small-Angle X-ray Scattering and X-ray Diffraction Coupled with Molecular Dynamics Analysis.

    PubMed

    Fleury, Blaise; Cortes-Huerto, Robinson; Taché, Olivier; Testard, Fabienne; Menguy, Nicolas; Spalla, Olivier

    2015-09-01

    Shape and size are known to determine a nanoparticle's properties. Hardly ever studied in synthesis, the internal crystal structure (i.e., particle defects, crystallinity, and symmetry) is just as critical as shape and size since it directly impacts catalytic efficiency, plasmon resonance, and orients anisotropic growth of metallic nanoparticles. Hence, its control cannot be ignored any longer in today's research and applications in nanotechnology. This study implemented an unprecedented reliable measurement combining these three structural aspects. The unified small-angle X-ray scattering and diffraction measurement (SAXS/XRD) was coupled with molecular dynamics to allow simultaneous determination of nanoparticles' shape, size, and crystallinity at the atomic scale. Symmetry distribution (icosahedra-Ih, decahedra-Dh, and truncated octahedra-TOh) of 2-6 nm colloidal gold nanoparticles synthesized in organic solvents was quantified. Nanoparticle number density showed the predominance of Ih, followed by Dh, and little, if any, TOh. This result contradicts some theoretical predictions and highlights the strong effect of the synthesis environment on structure stability. We foresee that this unified SAXS/XRD analysis, yielding both statistical and quantitative counts of nanoparticles' symmetry distribution, will provide new insights into nanoparticle formation, growth, and assembly. PMID:26263393

  12. Development and implementation of a finite element solution of the coupled neutron transport and thermoelastic equations governing the behavior of small nuclear assemblies

    NASA Astrophysics Data System (ADS)

    Wilson, Stephen Christian

    Small, highly enriched reactors designed for weapons effects simulations undergo extreme thermal transients during pulsed operations. The primary shutdown mechanism of these reactors---thermal expansion of fuel material---experiences an inertial delay resulting in a different value for the fuel temperature coefficient of reactivity during pulse operation as compared to the value appropriate for steady-state operation. The value appropriate for pulsed operation may further vary as a function of initial reactivity addition. Here we design and implement a finite element numerical method to predict the pulse operation behavior of Sandia Pulsed Reactor (SPR) II, SPR III, and a hypothetical spherical assembly with identical fuel properties without using operationally observed data in our model. These numerical results are compared to available SPR II and SPR III operational data. The numerical methods employed herein may be modified and expanded in functionality to provide both accurate characterization of the behavior of fast burst reactors of any common geometry or isotropic fuel material in the design phase, as well as a computational tool for general coupled thermomechanical-neutronics behavior in the solid state for any reactor type.

  13. Behaviour and stability of Trivelpiece-Gould modes in non-neutral plasma containing small density fraction of background gas ions

    SciTech Connect

    Yeliseyev, Y. N.

    2013-03-19

    It is shown that the frequencies of Trivelpiece-Gould (TG) modes in non-neutral plasma can get into the low-frequency range due to the Doppler shift caused by plasma rotation in crossed fields. TG modes interact with the ion modes that leads to plasma instability. In paper the frequency spectrum of 'cold' electron plasma completely filling a waveguide and containing small density fraction of ions of background gas is determined numerically. For ions the kinetic description is used. Oscillations having azimuthal number m= 2 are considered. In this case both low- and upper-hybrid TG modes get into the low-frequency range. The spectrum consists of families of 'modified' ion cyclotron (MIC) modes and electron TG modes with the frequencies equal to hybrid frequencies with the Doppler shift. The growth rates of upper-hybrid modes are much faster than the growth rates of low-hybrid and MIC modes.

  14. Small molecular probes for G-protein-coupled C5a receptors: conformationally constrained antagonists derived from the C terminus of the human plasma protein C5a.

    PubMed

    Wong, A K; Finch, A M; Pierens, G K; Craik, D J; Taylor, S M; Fairlie, D P

    1998-08-27

    Activation of the human complement system of plasma proteins in response to infection or injury produces a 4-helix bundle glycoprotein (74 amino acids) known as C5a. C5a binds to G-protein-coupled receptors on cell surfaces triggering receptor-ligand internalization, signal transduction, and powerful inflammatory responses. Since excessive levels of C5a are associated with autoimmune and chronic inflammatory disorders, inhibitors of receptor activation may have therapeutic potential. We now report solution structures and receptor-binding and antagonist activities for some of the first small molecule antagonists of C5a derived from its hexapeptide C terminus. The antagonist NMe-Phe-Lys-Pro-D-Cha-Trp-D-Arg-CO2H (1) surprisingly shows an unusually well-defined solution structure as determined by 1H NMR spectroscopy. This is one of the smallest acyclic peptides found to possess a defined solution conformation, which can be explained by the constraining role of intramolecular hydrogen bonding. NOE and coupling constant data, slow deuterium exchange, and a low dependence on temperature for the chemical shift of the D-Cha-NH strongly indicate an inverse gamma turn stabilized by a D-Cha-NH. OC-Lys hydrogen bond. Smaller conformational populations are associated with a hydrogen bond between Trp-NH.OC-Lys, defining a type II beta turn distorted by the inverse gamma turn incorporated within it. An excellent correlation between receptor-affinity and antagonist activity is indicated for a limited set of synthetic peptides. Conversion of the C-terminal carboxylate of 1 to an amide decreases antagonist potency 5-fold, but potency is increased up to 10-fold over 1 if the amide bond is made between the C-terminal carboxylate and a Lys/Orn side chain to form a cyclic analogue. The solution structure of cycle 6 also shows gamma and beta turns; however, the latter occurs in a different position, and there are clear conformational changes in 6 vs 1 that result in enhanced activity

  15. Behaviour of radiocaesium in coastal rivers of the Fukushima Prefecture (Japan) during conditions of low flow and low turbidity--Insight on the possible role of small particles and detrital organic compounds.

    PubMed

    Eyrolle-Boyer, Frédérique; Boyer, Patrick; Garcia-Sanchez, Laurent; Métivier, Jean-Michel; Onda, Yuichi; De Vismes, Anne; Cagnat, Xavier; Boulet, Béatrice; Cossonnet, Catherine

    2016-01-01

    To investigate riverine transfers from contaminated soils of the Fukushima Prefecture in Japan to the marine environment, suspended sediments, filtered water, sediments and detrital organic macro debris deposited onto river beds were collected in November 2013 within small coastal rivers during conditions of low flow rates and low turbidity. River waters were directly filtered on the field and high efficiency well-type Ge detectors were used to analyse radiocaesium concentrations in very small quantities of suspended particles and filtered water (a few mg to a few g). For such base-flow conditions, our results show that the watersheds studied present similar hydro-sedimentary behaviours at their outlets and that the exports of dissolved and particulate radiocaesium are comparable. Moreover, the contribution of these rivers to the instantaneous export of radiocaesium to the ocean is similar to that of the Abukuma River. Our preliminary results indicate that, in the estuaries, radiocaesium concentrations in suspended sediments would be reduced by more than 80%, while radiocaesium concentration in filtered waters would be maintained. Significant correlations between radiocaesium concentrations and radiocaesium inventories in the soils of the catchments indicate that there was at that time little intra and inter-watershed variability in the transfer processes of radiocaesium from lands to rivers at this regional scale. The apparent liquid-solid partition coefficient (KD) values acquired for the lowest loads/finest particles complement the values acquired by using sediment traps and highlight the strong capacity of the smallest particles to transfer radiocaesium. Finally, but not least, our observations suggest that there could be a significant transfer of highly contaminated detrital biomass from forest litter to the downstream rivers in a rather conservative way. PMID:26588202

  16. Magnetoelectric coupling study in multiferroic Pb(Fe{sub 0.5}Nb{sub 0.5})O{sub 3} ceramics through small and large electric signal standard measurements

    SciTech Connect

    Raymond, Oscar; Siqueiros, Jesus M.; Font, Reynaldo; Portelles, Jorge

    2011-05-01

    Multifunctional multiferroic materials such as the single phase compound Pb(Fe{sub 0.5}Nb{sub 0.5})O{sub 3} (PFN), where ferroelectric and antiferromagnetic order coexist, are very promising and have great interest from the academic and technological points of view. In this work, coupling of the ferroelectric and magnetic moments is reported. For this study, a combination of the small signal response using the impedance spectroscopy technique and the electromechanical resonance method with the large signal response through standard ferroelectric hysteresis measurement, has been used with and without an applied magnetic field. The measurements to determine the electrical properties of the ceramic were performed as functions of the bias and poling electric fields. A simultaneous analysis of the complex dielectric constant {epsilon}-tilde, impedance Z-tilde, electric modulus M-tilde, admittance Y-tilde, and the electromechanical parameters and coupling factors is presented. The results are correlated with a previous study of structural, morphological, small signal dielectric frequency-temperature response, and the ferroelectric hysteretic, magnetic and magnetodielectric behaviors. The observed shifts of the resonance and antiresonance frequency values can be associated with change of the ferroelectric domain size favored by the readjustment of the oxygen octahedron when the magnetic field is applied. From P-E hysteresis loops obtained without and with an external applied magnetic field, a dc magnetoelectric coupling effect with maximum value of 4 kV/cm T (400 mV/cm Oe) was obtained.

  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. Small-dilution correction to the spin-wave dispersion in the Heisenberg ferromagnet with first-, second-, and third-neighbor exchange coupling

    NASA Astrophysics Data System (ADS)

    Tahir-Kheli, R. A.

    1984-02-01

    An exact expression for the small-dilution correction to the long-wavelength spin-wave dispersion in Heisenberg ferromagnets at low temperatures is derived by the transcription of the analysis of the preceding paper. Numerical results to six decimal places are presented for a variety of exchange integrals extending up to the third-neighbor shell.

  19. Working with What We've Got: Perceptions of Barriers and Supports among Small-Metropolitan-Area Same-Sex Adopting Couples

    ERIC Educational Resources Information Center

    Kinkler, Lori A.; Goldberg, Abbie E.

    2011-01-01

    In seeking to adopt, lesbians and gay men may confront various barriers and obstacles. Ideally, they have access to a variety of support resources that can help to buffer the negative effects of these barriers. Lesbians and gay men living in small metropolitan communities may have limited access to support resources, however. The current…

  20. Amplitudes of protein backbone dynamics and correlated motions in a small alpha/beta protein: correspondence of dipolar coupling and heteronuclear relaxation measurements.

    PubMed

    Clore, G Marius; Schwieters, Charles D

    2004-08-24

    Backbone residual dipolar coupling (N-H, Calpha-Halpha, N-C', and Calpha-C') data collected in five different media on the B3 IgG binding domain of streptococcal protein G (GB3) have been analyzed by simultaneous refinement of the coordinates and optimization of the magnitudes and orientations of the alignment tensors using single and multiple structure representations. We show, using appropriate error analysis, that agreement between observed and calculated dipolar couplings at the level of experimental uncertainty is obtained with a two-structure (N(e) = 2) ensemble representation which represents the simplest equilibrium description of anisotropic motions. The data permit one to determine the magnitude of the anisotropic motions along the four different backbone bond vectors in terms of order parameters. The order parameters, , for the N-H bond vectors are in qualitative agreement with the generalized order parameters, S(2)NH(relaxation), derived from (15)N relaxation measurements, with a correlation coefficient of 0.84. S(2)NH(relaxation) can be regarded as the product of an anisotropic order parameter, corresponding to derived from the residual dipolar couplings, and an axially symmetric order parameter, S(2)NH(axial), corresponding to bond librations which are expected to be essentially uniform along the polypeptide chain. The current data indicate that the average value of S(2)NH(axial) is approximately 0.9. The close correspondence of and S(2)NH(relaxation) indicates that any large-scale displacements from the mean coordinate positions on time scales longer than the rotational correlation time are rare and hence do not perturb the observed dipolar couplings. Analysis of a set of 100 N(e) = 2 ensembles reveals the presence of some long-range correlated motions of N-H and Calpha-Halpha vectors involving residues far apart in the sequence but close together in space. In addition, direct evidence is

  1. Spin-orbit coupling and chaotic rotation for circumbinary bodies. Application to the small satellites of the Pluto-Charon system

    NASA Astrophysics Data System (ADS)

    Correia, Alexandre C. M.; Leleu, Adrien; Rambaux, Nicolas; Robutel, Philippe

    2015-08-01

    We investigate the resonant rotation of circumbinary bodies in planar quasi-circular orbits. Denoting nb and n the orbital mean motion of the inner binary and of the circumbinary body, respectively, we show that spin-orbit resonances exist at the frequencies n ± kν/2, where ν = nb - n, and k is an integer. Moreover, when the libration at natural frequency has the same magnitude as ν, the resonances overlap and the rotation becomes chaotic. We apply these results to the small satellites in the Pluto-Charon system, and conclude that their rotations are likely chaotic. However, the rotation can also be stable and not synchronous for small axial asymmetries. Figure 4 and Appendices are available in electronic form at http://www.aanda.org

  2. Demonstration of a fully-coupled end-to-end model for small pelagic fish using sardine and anchovy in the California Current

    NASA Astrophysics Data System (ADS)

    Rose, Kenneth A.; Fiechter, Jerome; Curchitser, Enrique N.; Hedstrom, Kate; Bernal, Miguel; Creekmore, Sean; Haynie, Alan; Ito, Shin-ichi; Lluch-Cota, Salvador; Megrey, Bernard A.; Edwards, Chris A.; Checkley, Dave; Koslow, Tony; McClatchie, Sam; Werner, Francisco; MacCall, Alec; Agostini, Vera

    2015-11-01

    We describe and document an end-to-end model of anchovy and sardine population dynamics in the California Current as a proof of principle that such coupled models can be developed and implemented. The end-to-end model is 3-dimensional, time-varying, and multispecies, and consists of four coupled submodels: hydrodynamics, Eulerian nutrient-phytoplankton-zooplankton (NPZ), an individual-based full life cycle anchovy and sardine submodel, and an agent-based fishing fleet submodel. A predator roughly mimicking albacore was included as individuals that consumed anchovy and sardine. All submodels were coded within the ROMS open-source community model, and used the same resolution spatial grid and were all solved simultaneously to allow for possible feedbacks among the submodels. We used a super-individual approach and solved the coupled models on a distributed memory parallel computer, both of which created challenging but resolvable bookkeeping challenges. The anchovy and sardine growth, mortality, reproduction, and movement, and the fishing fleet submodel, were each calibrated using simplified grids before being inserted into the full end-to-end model. An historical simulation of 1959-2008 was performed, and the latter 45 years analyzed. Sea surface height (SSH) and sea surface temperature (SST) for the historical simulation showed strong horizontal gradients and multi-year scale temporal oscillations related to various climate indices (PDO, NPGO), and both showed responses to ENSO variability. Simulated total phytoplankton was lower during strong El Nino events and higher for the strong 1999 La Nina event. The three zooplankton groups generally corresponded to the spatial and temporal variation in simulated total phytoplankton. Simulated biomasses of anchovy and sardine were within the historical range of observed biomasses but predicted biomasses showed much less inter-annual variation. Anomalies of annual biomasses of anchovy and sardine showed a switch in the mid

  3. 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.

  4. Parasitic small-moment antiferromagnetism and nonlinear coupling of hidden order and antiferromagnetism in URu2Si2 observed by Larmor diffraction.

    PubMed

    Niklowitz, P G; Pfleiderer, C; Keller, T; Vojta, M; Huang, Y-K; Mydosh, J A

    2010-03-12

    We report for the first time simultaneous microscopic measurements of the lattice constants, the distribution of the lattice constants, and the antiferromagnetic moment in high-purity URu(2)Si(2), combining Larmor and conventional neutron diffraction at low temperatures and pressures up to 18 kbar. Our data demonstrate quantitatively that the small moment in the hidden order (HO) of URu(2)Si(2) is purely parasitic. The excellent experimental conditions we achieve allow us to resolve that the transition line between HO and large-moment antiferromagnetism (LMAF), which stabilizes under pressure, is intrinsically first order and ends in a bicritical point. Therefore, the HO and LMAF must have different symmetry, which supports exotic scenarios of the HO such as orbital currents, helicity order, or multipolar order. PMID:20366444

  5. Activation of EGFR by small compounds through coupling the generation of hydrogen peroxide to stable dimerization of Cu/Zn SOD1

    PubMed Central

    Sakanyan, Vehary; Hulin, Philippe; Alves de Sousa, Rodolphe; Silva, Viviane A. O.; Hambardzumyan, Artur; Nedellec, Steven; Tomasoni, Christophe; Logé, Cédric; Pineau, Charles; Roussakis, Christos; Fleury, Fabrice; Artaud, Isabelle

    2016-01-01

    Activation of cell signaling by reactive chemicals and pollutants is an important issue for human health. It has been shown that lipophilic nitro-benzoxadiazole (NBD) compounds rapidly move across the plasma membrane and enhance Epidermal Growth Factor Receptor (EGFR) tyrosine phosphorylation in cancer cells. Unlike ligand-dependent activation, the mechanism of this induction relies on the generation of hydrogen peroxide, which is involved in the activation of the catalytic site of the receptor and the inactivation of protein tyrosine phosphatase PTP-1B. Production of H2O2 during redox transformation of NBD compounds is associated with the transition of a monomeric form of Cu/Zn superoxide dismutase 1 (SOD1) to stable dimers. The highly stable and functionally active SOD1 dimer, in the absence of adequate activities in downstream reactions, promotes the disproportionate production and accumulation of intracellular hydrogen peroxide shortly after exposure to NBD compounds. The intrinsic fluorescence of small compounds was used to demonstrate their binding to SOD1. Our data indicate that H2O2 and concomitantly generated electrophilic intermediates behave as independent entities, but all contribute to the biological reactivity of NBD compounds. This study opens a promising path to identify new biomarkers of oxidative/electrophilic stress in the progression of cancer and other diseases. PMID:26883293

  6. Distinctive profiles of small RNA couple inverted repeat-induced post-transcriptional gene silencing with endogenous RNA silencing pathways in Arabidopsis

    PubMed Central

    Matvienko, Marta; Piskurewicz, Urszula; Xu, Huaqin; Martineau, Belinda; Wong, Joan; Govindarajulu, Manjula; Kozik, Alexander; Michelmore, Richard W.

    2014-01-01

    The experimental induction of RNA silencing in plants often involves expression of transgenes encoding inverted repeat (IR) sequences to produce abundant dsRNAs that are processed into small RNAs (sRNAs). These sRNAs are key mediators of post-transcriptional gene silencing (PTGS) and determine its specificity. Despite its application in agriculture and broad utility in plant research, the mechanism of IR-PTGS is incompletely understood. We generated four sets of 60 Arabidopsis plants, each containing IR transgenes expressing different configurations of uidA and CHALCONE SYNTHASE (At-CHS) gene fragments. Levels of PTGS were found to depend on the orientation and position of the fragment in the IR construct. Deep sequencing and mapping of sRNAs to corresponding transgene-derived and endogenous transcripts identified distinctive patterns of differential sRNA accumulation that revealed similarities among sRNAs associated with IR-PTGS and endogenous sRNAs linked to uncapped mRNA decay. Detailed analyses of poly-A cleavage products from At-CHS mRNA confirmed this hypothesis. We also found unexpected associations between sRNA accumulation and the presence of predicted open reading frames in the trigger sequence. In addition, strong IR-PTGS affected the prevalence of endogenous sRNAs, which has implications for the use of PTGS for experimental or applied purposes. PMID:25344399

  7. A rapid procedure for the determination of thorium, uranium, cadmium and molybdenum in small sediment samples by inductively coupled plasma-mass spectrometry: Application in Chesapeake Bay

    USGS Publications Warehouse

    Zheng, Yen; Weinman, B.; Cronin, T.; Fleisher, M.Q.; Anderson, Robert F.

    2003-01-01

    This paper describes a rapid procedure that allows precise analysis of Mo, Cd, U and Th in sediment samples as small as 10 mg by using a novel approach that utilizes a "pseudo" isotope dilution for Th and conventional isotope dilution for Mo, Cd and U by ICP-MS. Long-term reproducibility of the method is between 2.5 and 5% with an advantage of rapid analysis on a single digestion of sediment sample and the potential of adding other elements of interest if so desired. Application of this method to two piston cores collected near the mouth of the Patuxent River in Chesapeake Bay showed that the accumulation of authigenic Mo and Cd varied in response to the changing bottom water redox conditions, with anoxia showing consistent oscillations throughout both pre-industrial and industrial times. Accumulation of authigenic U shows consistent oscillations as well, without any apparent increase in productivity related to anoxic trends. Degrees of Mo and Cd enrichment also inversely correlate to halophilic microfaunal assemblages already established as paleoclimate proxies within the bay indicating that bottom water anoxia is driven in part by the amount of freshwater discharge that the area receives. ?? 2002 Elsevier Science Ltd. All rights reserved.

  8. Distinctive profiles of small RNA couple inverted repeat-induced post-transcriptional gene silencing with endogenous RNA silencing pathways in Arabidopsis.

    PubMed

    Wroblewski, Tadeusz; Matvienko, Marta; Piskurewicz, Urszula; Xu, Huaqin; Martineau, Belinda; Wong, Joan; Govindarajulu, Manjula; Kozik, Alexander; Michelmore, Richard W

    2014-12-01

    The experimental induction of RNA silencing in plants often involves expression of transgenes encoding inverted repeat (IR) sequences to produce abundant dsRNAs that are processed into small RNAs (sRNAs). These sRNAs are key mediators of post-transcriptional gene silencing (PTGS) and determine its specificity. Despite its application in agriculture and broad utility in plant research, the mechanism of IR-PTGS is incompletely understood. We generated four sets of 60 Arabidopsis plants, each containing IR transgenes expressing different configurations of uidA and CHALCONE Synthase (At-CHS) gene fragments. Levels of PTGS were found to depend on the orientation and position of the fragment in the IR construct. Deep sequencing and mapping of sRNAs to corresponding transgene-derived and endogenous transcripts identified distinctive patterns of differential sRNA accumulation that revealed similarities among sRNAs associated with IR-PTGS and endogenous sRNAs linked to uncapped mRNA decay. Detailed analyses of poly-A cleavage products from At-CHS mRNA confirmed this hypothesis. We also found unexpected associations between sRNA accumulation and the presence of predicted open reading frames in the trigger sequence. In addition, strong IR-PTGS affected the prevalence of endogenous sRNAs, which has implications for the use of PTGS for experimental or applied purposes. PMID:25344399

  9. The detection method for small molecules coupled with a molecularly imprinted polymer/quantum dot chip using a home-built optical system.

    PubMed

    Liu, Yixi; Wang, Yong; Liu, Le; He, Yonghong; He, Qinghua; Ji, Yanhong

    2016-07-01

    A method to detect small molecules with a molecularly imprinted polymer/quantum dot (MIP-QD) chip using a home-built optical fluidic system was first proposed in this study. Ractopamine (RAC) was used as the model molecule to demonstrate its feasibility. The sensing of the target molecule is based on the quenching amount of the quantum dots. The method is facile, cost-saving, easy for miniaturization and avoids the cumbersome steps that are needed to get the fluorescent quenching curve using a spectrofluorometer. Most importantly, more details and accurate response time can be obtained by use of this method. The experimental results show that the prepared chips with low cost are highly selective and the home-built detection system allows the fast binding kinetics. The recorded quenching process was used to study the kinetic uptake of RAC onto the MIP-QD chip and the specificity towards RAC. The system can further be utilized to study the effect of the solvent, pH and temperature on the selectivity of the prepared MIP. The methodology could be extended to other similar studies with different molecules. Graphical abstract Schematic illustration of the molecularly imprinted polymer/quantum dot chip capturing the target molecule. PMID:27235159

  10. Activation of EGFR by small compounds through coupling the generation of hydrogen peroxide to stable dimerization of Cu/Zn SOD1.

    PubMed

    Sakanyan, Vehary; Hulin, Philippe; Alves de Sousa, Rodolphe; Silva, Viviane A O; Hambardzumyan, Artur; Nedellec, Steven; Tomasoni, Christophe; Logé, Cédric; Pineau, Charles; Roussakis, Christos; Fleury, Fabrice; Artaud, Isabelle

    2016-01-01

    Activation of cell signaling by reactive chemicals and pollutants is an important issue for human health. It has been shown that lipophilic nitro-benzoxadiazole (NBD) compounds rapidly move across the plasma membrane and enhance Epidermal Growth Factor Receptor (EGFR) tyrosine phosphorylation in cancer cells. Unlike ligand-dependent activation, the mechanism of this induction relies on the generation of hydrogen peroxide, which is involved in the activation of the catalytic site of the receptor and the inactivation of protein tyrosine phosphatase PTP-1B. Production of H2O2 during redox transformation of NBD compounds is associated with the transition of a monomeric form of Cu/Zn superoxide dismutase 1 (SOD1) to stable dimers. The highly stable and functionally active SOD1 dimer, in the absence of adequate activities in downstream reactions, promotes the disproportionate production and accumulation of intracellular hydrogen peroxide shortly after exposure to NBD compounds. The intrinsic fluorescence of small compounds was used to demonstrate their binding to SOD1. Our data indicate that H2O2 and concomitantly generated electrophilic intermediates behave as independent entities, but all contribute to the biological reactivity of NBD compounds. This study opens a promising path to identify new biomarkers of oxidative/electrophilic stress in the progression of cancer and other diseases. PMID:26883293

  11. Ray Tracing to Predict Optical Behaviour of Shock Compressed Dielectrics

    NASA Astrophysics Data System (ADS)

    Tear, Gareth R.; Proud, William G.

    2015-06-01

    In order to investigate the optical response of dielectric materials under shock compression, a characteristics model has been combined with a three dimensional optical ray tracing model. A general biaxial optical model is used along with a first order photoelastic model which couples the characteristics component to the optical component. This optical model is three dimensional and as such can be used to investigate small deviations from the perfect one dimensional shock wave which is typically assumed in plate impact experiments. A detailed description of the model will be presented, and comparison to available literature as well as recent experiments on the optical behaviour of shock compressed a-cut calcite and a-cut sapphire. The authors would like to thank Dr D E Eakins and Dr D J Chapman for fruitful discussions. The Institute of Shock Physics acknowledges the continued support of AWE and Imperial College London.

  12. Principal Component Analysis Coupled with Artificial Neural Networks—A Combined Technique Classifying Small Molecular Structures Using a Concatenated Spectral Database

    PubMed Central

    Gosav, Steluţa; Praisler, Mirela; Birsa, Mihail Lucian

    2011-01-01

    In this paper we present several expert systems that predict the class identity of the modeled compounds, based on a preprocessed spectral database. The expert systems were built using Artificial Neural Networks (ANN) and are designed to predict if an unknown compound has the toxicological activity of amphetamines (stimulant and hallucinogen), or whether it is a nonamphetamine. In attempts to circumvent the laws controlling drugs of abuse, new chemical structures are very frequently introduced on the black market. They are obtained by slightly modifying the controlled molecular structures by adding or changing substituents at various positions on the banned molecules. As a result, no substance similar to those forming a prohibited class may be used nowadays, even if it has not been specifically listed. Therefore, reliable, fast and accessible systems capable of modeling and then identifying similarities at molecular level, are highly needed for epidemiological, clinical, and forensic purposes. In order to obtain the expert systems, we have preprocessed a concatenated spectral database, representing the GC-FTIR (gas chromatography-Fourier transform infrared spectrometry) and GC-MS (gas chromatography-mass spectrometry) spectra of 103 forensic compounds. The database was used as input for a Principal Component Analysis (PCA). The scores of the forensic compounds on the main principal components (PCs) were then used as inputs for the ANN systems. We have built eight PC-ANN systems (principal component analysis coupled with artificial neural network) with a different number of input variables: 15 PCs, 16 PCs, 17 PCs, 18 PCs, 19 PCs, 20 PCs, 21 PCs and 22 PCs. The best expert system was found to be the ANN network built with 18 PCs, which accounts for an explained variance of 77%. This expert system has the best sensitivity (a rate of classification C = 100% and a rate of true positives TP = 100%), as well as a good selectivity (a rate of true negatives TN = 92.77%). A

  13. Ultra-trace plutonium determination in small volume seawater by sector field inductively coupled plasma mass spectrometry with application to Fukushima seawater samples.

    PubMed

    Bu, Wenting; Zheng, Jian; Guo, Qiuju; Aono, Tatsuo; Tagami, Keiko; Uchida, Shigeo; Tazoe, Hirofumi; Yamada, Masatoshi

    2014-04-11

    Long-term monitoring of Pu isotopes in seawater is required for assessing Pu contamination in the marine environment from the Fukushima Dai-ichi Nuclear Power Plant accident. In this study, we established an accurate and precise analytical method based on anion-exchange chromatography and SF-ICP-MS. This method was able to determine Pu isotopes in seawater samples with small volumes (20-60L). The U decontamination factor was 3×10(7)-1×10(8), which provided sufficient removal of interfering U from the seawater samples. The estimated limits of detection for (239)Pu and (240)Pu were 0.11fgmL(-1) and 0.08fgmL(-1), respectively, which corresponded to 0.01mBqm(-3) for (239)Pu and 0.03mBqm(-3) for (240)Pu when a 20L volume of seawater was measured. We achieved good precision (2.9%) and accuracy (0.8%) for measurement of the (240)Pu/(239)Pu atom ratio in the standard Pu solution with a (239)Pu concentration of 11fgmL(-1) and (240)Pu concentration of 2.7fgmL(-1). Seawater reference materials were used for the method validation and both the (239+240)Pu activities and (240)Pu/(239)Pu atom ratios agreed well with the expected values. Surface and bottom seawater samples collected off Fukushima in the western North Pacific since March 2011 were analyzed. Our results suggested that there was no significant variation of the Pu distribution in seawater in the investigated areas compared to the distribution before the accident. PMID:24636561

  14. Dynamics of climate and ecosystem coupling: abrupt changes and multiple equilibria.

    PubMed Central

    Higgins, Paul A T; Mastrandrea, Michael D; Schneider, Stephen H

    2002-01-01

    Interactions between subunits of the global climate-biosphere system (e.g. atmosphere, ocean, biosphere and cryosphere) often lead to behaviour that is not evident when each subunit is viewed in isolation. This newly evident behaviour is an emergent property of the coupled subsystems. Interactions between thermohaline circulation and climate illustrate one emergent property of coupling ocean and atmospheric circulation. The multiple thermohaline circulation equilibria that result caused abrupt climate changes in the past and may cause abrupt climate changes in the future. Similarly, coupling between the climate system and ecosystem structure and function produces complex behaviour in certain regions. For example, atmosphere-biosphere interactions in the Sahel region of West Africa lead to multiple stable equilibria. Either wet or dry climate equilibria can occur under otherwise identical forcing conditions. The equilibrium reached is dependent on past history (i.e. initial conditions), and relatively small perturbations to either climate or vegetation can cause switching between the two equilibria. Both thermohaline circulation and the climate-vegetation system in the Sahel are prone to abrupt changes that may be irreversible. This complicates the relatively linear view of global changes held in many scientific and policy communities. Emergent properties of coupled socio-natural systems add yet another layer of complexity to the policy debate. As a result, the social and economic consequences of possible global changes are likely to be underestimated in most conventional analyses because these nonlinear, abrupt and irreversible responses are insufficiently considered. PMID:12079526

  15. Dynamics of climate and ecosystem coupling: abrupt changes and multiple equilibria.

    PubMed

    Higgins, Paul A T; Mastrandrea, Michael D; Schneider, Stephen H

    2002-05-29

    Interactions between subunits of the global climate-biosphere system (e.g. atmosphere, ocean, biosphere and cryosphere) often lead to behaviour that is not evident when each subunit is viewed in isolation. This newly evident behaviour is an emergent property of the coupled subsystems. Interactions between thermohaline circulation and climate illustrate one emergent property of coupling ocean and atmospheric circulation. The multiple thermohaline circulation equilibria that result caused abrupt climate changes in the past and may cause abrupt climate changes in the future. Similarly, coupling between the climate system and ecosystem structure and function produces complex behaviour in certain regions. For example, atmosphere-biosphere interactions in the Sahel region of West Africa lead to multiple stable equilibria. Either wet or dry climate equilibria can occur under otherwise identical forcing conditions. The equilibrium reached is dependent on past history (i.e. initial conditions), and relatively small perturbations to either climate or vegetation can cause switching between the two equilibria. Both thermohaline circulation and the climate-vegetation system in the Sahel are prone to abrupt changes that may be irreversible. This complicates the relatively linear view of global changes held in many scientific and policy communities. Emergent properties of coupled socio-natural systems add yet another layer of complexity to the policy debate. As a result, the social and economic consequences of possible global changes are likely to be underestimated in most conventional analyses because these nonlinear, abrupt and irreversible responses are insufficiently considered. PMID:12079526

  16. A meta-analysis of the effects of measuring theory of planned behaviour constructs on behaviour within prospective studies.

    PubMed

    Mankarious, Evon; Kothe, Emily

    2015-01-01

    Measurement reactivity effects, such as the mere measurement effect, have been proposed as a reason for behavioural changes in a number of theory of planned behaviour intervention studies. However, it is unclear whether such changes are the result of the mere measurement effect or of other artefacts of intervention study design. The aim of this study is to determine the size and direction of changes in health behaviours from baseline to follow-up in prospective studies using the theory of planned behaviour. Electronic databases were searched for the theory of planned behaviour studies which measured health behaviours at two or more time points. Change in behaviour was calculated for all studies. Sixty-six studies were included. Mean effect sizes across all studies were small and negative (d = -.03). Effect size was moderated by behaviour, behaviour type and follow-up length. Subgroup analyses showed significant decreases in socially undesirable behaviour (d = -.28), binge drinking (d = -.17), risk driving (d = -.20), sugar snack consumption (d = -.43) and sun-protective behaviour (d = -.18). Measurement of intention at baseline resulted in significant decreases in undesirable behaviour. Changes in undesirable behaviours reported in other studies may be the result of the mere measurement effect. PMID:26209208

  17. The influence of social norms on the dynamics of vaccinating behaviour for paediatric infectious diseases.

    PubMed

    Oraby, Tamer; Thampi, Vivek; Bauch, Chris T

    2014-04-01

    Mathematical models that couple disease dynamics and vaccinating behaviour often assume that the incentive to vaccinate disappears if disease prevalence is zero. Hence, they predict that vaccine refusal should be the rule, and elimination should be difficult or impossible. In reality, countries with non-mandatory vaccination policies have usually been able to maintain elimination or very low incidence of paediatric infectious diseases for long periods of time. Here, we show that including injunctive social norms can reconcile such behaviour-incidence models to observations. Adding social norms to a coupled behaviour-incidence model enables the model to better explain pertussis vaccine uptake and disease dynamics in the UK from 1967 to 2010, in both the vaccine-scare years and the years of high vaccine coverage. The model also illustrates how a vaccine scare can perpetuate suboptimal vaccine coverage long after perceived risk has returned to baseline, pre-vaccine-scare levels. However, at other model parameter values, social norms can perpetuate depressed vaccine coverage during a vaccine scare well beyond the time when the population's baseline vaccine risk perception returns to pre-scare levels. Social norms can strongly suppress vaccine uptake despite frequent outbreaks, as observed in some small communities. Significant portions of the parameter space also exhibit bistability, meaning long-term outcomes depend on the initial conditions. Depending on the context, social norms can either support or hinder immunization goals. PMID:24523276

  18. The influence of social norms on the dynamics of vaccinating behaviour for paediatric infectious diseases

    PubMed Central

    Oraby, Tamer; Thampi, Vivek; Bauch, Chris T.

    2014-01-01

    Mathematical models that couple disease dynamics and vaccinating behaviour often assume that the incentive to vaccinate disappears if disease prevalence is zero. Hence, they predict that vaccine refusal should be the rule, and elimination should be difficult or impossible. In reality, countries with non-mandatory vaccination policies have usually been able to maintain elimination or very low incidence of paediatric infectious diseases for long periods of time. Here, we show that including injunctive social norms can reconcile such behaviour-incidence models to observations. Adding social norms to a coupled behaviour-incidence model enables the model to better explain pertussis vaccine uptake and disease dynamics in the UK from 1967 to 2010, in both the vaccine-scare years and the years of high vaccine coverage. The model also illustrates how a vaccine scare can perpetuate suboptimal vaccine coverage long after perceived risk has returned to baseline, pre-vaccine-scare levels. However, at other model parameter values, social norms can perpetuate depressed vaccine coverage during a vaccine scare well beyond the time when the population's baseline vaccine risk perception returns to pre-scare levels. Social norms can strongly suppress vaccine uptake despite frequent outbreaks, as observed in some small communities. Significant portions of the parameter space also exhibit bistability, meaning long-term outcomes depend on the initial conditions. Depending on the context, social norms can either support or hinder immunization goals. PMID:24523276

  19. Coupled transverse motion

    SciTech Connect

    Teng, L.C.

    1989-01-01

    The magnetic field in an accelerator or a storage ring is usually so designed that the horizontal (x) and the vertical (y) motions of an ion are uncoupled. However, because of imperfections in construction and alignment, some small coupling is unavoidable. In this lecture, we discuss in a general way what is known about the behaviors of coupled motions in two degrees-of-freedom. 11 refs., 6 figs.

  20. Evolution of central pattern generators and rhythmic behaviours.

    PubMed

    Katz, Paul S

    2016-01-01

    Comparisons of rhythmic movements and the central pattern generators (CPGs) that control them uncover principles about the evolution of behaviour and neural circuits. Over the course of evolutionary history, gradual evolution of behaviours and their neural circuitry within any lineage of animals has been a predominant occurrence. Small changes in gene regulation can lead to divergence of circuit organization and corresponding changes in behaviour. However, some behavioural divergence has resulted from large-scale rewiring of the neural network. Divergence of CPG circuits has also occurred without a corresponding change in behaviour. When analogous rhythmic behaviours have evolved independently, it has generally been with different neural mechanisms. Repeated evolution of particular rhythmic behaviours has occurred within some lineages due to parallel evolution or latent CPGs. Particular motor pattern generating mechanisms have also evolved independently in separate lineages. The evolution of CPGs and rhythmic behaviours shows that although most behaviours and neural circuits are highly conserved, the nature of the behaviour does not dictate the neural mechanism and that the presence of homologous neural components does not determine the behaviour. This suggests that although behaviour is generated by neural circuits, natural selection can act separately on these two levels of biological organization. PMID:26598733

  1. 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

  2. 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.

  3. 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

  4. Behaviour Profile of Hungarian Adolescent Outpatients with a Dual Diagnosis

    ERIC Educational Resources Information Center

    Dinya, Elek; Csorba, Janos; Suli, Agota; Grosz, Zsofia

    2012-01-01

    The behaviour dimensions of 244 Hungarian adolescent psychiatric outpatients with a dual diagnosis (intellectual disability and psychiatric diagnosis) were examined by means of the adapted version of the Behaviour Problem Inventory (BPI, Rojahn, Matson, Lott, Esbensen, & Smalls, 2001). Four IQ subgroups were created: borderline, mild, moderate and…

  5. Time, Space and Gender: Understanding "Problem" Behaviour in Young Children

    ERIC Educational Resources Information Center

    Brown, Jane

    2007-01-01

    The following article reports on a small-scale, exploratory study of aggressive and "problem" behaviour in pre-school children. This project was conceived in the wider context of anxieties about childhood and New Labour's policy focus on "anti-social" behaviour in children. Based on interviews with nursery staff and parents in addition to…

  6. 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

  7. Coexisting Problem Behaviour in Severe Dyslexia

    ERIC Educational Resources Information Center

    Dahle, Anne Elisabeth; Knivsberg, Ann-Mari; Andreassen, Anne Brit

    2011-01-01

    A small group of children and young adolescent with dyslexia has severely impaired reading skills despite prolonged special education. These are the students in focus. In dyslexia, problem behaviour, internalised as well as externalised, has previously been reported, so also for the participants with dyslexia in this study. The aim of the present…

  8. 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

  9. Solution Structure of the 128 kDa Enzyme I Dimer from Escherichia coli and its 146 kDa Complex With HPr Using Residual Dipolar Couplings and Small and Wide Angle X-Ray Scattering

    PubMed Central

    Schwieters, Charles D.; Suh, Jeong-Yong; Grishaev, Alexander; Ghirlando, Rodolfo; Takayama, Yuki; Clore, G. Marius

    2010-01-01

    The solution structures of free Enzyme I (EI, ∼128 kDa, 575×2 residues), the first enzyme in the bacterial phosphotransferse system and its complex with HPr (∼146 kDa) have been solved using novel methodology that makes use of prior structural knowledge (namely, the structures of the dimeric EIC domain and the isolated EIN domain both free and complexed to HPr), combined with residual dipolar coupling (RDC), small (SAXS) and wide (WAXS) angle X-ray scattering and small angle neutron scattering (SANS) data. The calculational strategy employs conjoined rigid body/torsion/Cartesian simulated annealing, and incorporates improvements in calculating and refining against SAXS/WAXS data that take into account complex molecular shapes in the description of the solvent layer resulting in a better representation of the SAXS/WAXS data. The RDC data orient the symmetrically related EIN domains relative to the C2 symmetry axis of the EIC dimer, while translational, shape and size information is provided by SAXS/WAXS. The resulting structures are independently validated by SANS. Comparison of the structures of the free EI and the EI-HPr complex with that of the crystal structure of a trapped phosphorylated EI intermediate reveals large (∼70-90°) hinge body rotations of the two subdomains comprising the EIN domain, as well as of the EIN domain relative to the dimeric EIC domain. These large-scale interdomain motions shed light on the structural transitions that accompany the catalytic cycle of EI. PMID:20731394

  10. Towards an integrated approach of pedestrian behaviour and exposure.

    PubMed

    Papadimitriou, Eleonora

    2016-07-01

    In this paper, an integrated methodology for the analysis of pedestrian behaviour and exposure is proposed, allowing to identify and quantify the effect of pedestrian behaviour, road and traffic characteristics on pedestrian risk exposure, for each pedestrian and for populations of pedestrians. The paper builds on existing research on pedestrian exposure, namely the Routledge microscopic indicator, proposes adjustments to take into account road, traffic and human factors and extends the use of this indicator on area-wide level. Moreover, this paper uses integrated choice and latent variables (ICLV) models of pedestrian behaviour, taking into account road, traffic and human factors. Finally, a methodology is proposed for the integrated estimation of pedestrian behaviour and exposure on the basis of road, traffic and human factors. The method is tested with data from a field survey in Athens, Greece, which used pedestrian behaviour observations as well as a questionnaire on human factors of pedestrian behaviour. The data were used (i) to develop ICLV models of pedestrian behaviour and (ii) to estimate the behaviour and exposure of pedestrians for different road, traffic and behavioural scenarios. The results suggest that both pedestrian behaviour and exposure are largely defined by a small number of factors: road type, traffic volume and pedestrian risk-taking. The probability for risk-taking behaviour and the related exposure decrease in less demanding road and traffic environments. A synthesis of the results allows to enhance the understanding of the interactions between behaviour and exposure of pedestrians and to identify conditions of increased risk exposure. These conditions include principal urban arterials (where risk-taking behaviour is low but the related exposure is very high) and minor arterials (where risk-taking behaviour is more frequent, and the related exposure is still high). A "paradox" of increased risk-taking behaviour of pedestrians with low

  11. 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.

  12. 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.

  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. 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

  15. 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

  16. Polyalkynylanthracenes--syntheses, structures and their behaviour towards UV irradiation.

    PubMed

    Lamm, Jan-Hendrik; Glatthor, Johanna; Weddeling, Jan-Henrik; Mix, Andreas; Chmiel, Jasmin; Neumann, Beate; Stammler, Hans-Georg; Mitzel, Norbert W

    2014-10-01

    A series of bis- and tris[(trimethylsilyl)ethynyl]anthracenes (1,5-, 1,8-, 9,10- and 1,8,10-) has been synthesised by multistep (cross coupling) reactions and the behaviour of the SiMe3-functionalised alkynylanthracene derivatives towards UV irradiation was qualitatively studied by NMR spectroscopy. In the case of 9,10-bis[(trimethylsilyl)ethynyl]anthracene we observed a photodimerisation upon UV irradiation; the third example was reported for a symmetrically 9,10-difunctionalised anthracene derivative, besides those with small fluorine- and methyl-substituents. The anthracene dimerisation is completely thermally reversible and the temperature dependence of the cycloelimination reaction was studied by (1)H VT-NMR experiments. The (deprotected) 1,5- and 1,8-diethynylanthracenes were converted with (dimethylamino)trimethylstannane to obtain the corresponding SnMe3-functionalised alkynes, potentially useful as highly conjugated building blocks in Stille cross coupling reactions. The new anthracene compounds were completely characterised by multinuclear NMR spectroscopy, (high resolution) mass spectrometry and - in most cases - by X-ray diffraction experiments. PMID:25162922

  17. Strong coupling in the sub-wavelength limit using metamaterial nanocavities

    PubMed Central

    Benz, A.; Campione, S.; Liu, S.; Montaño, I.; Klem, J.F.; Allerman, A; Wendt, J.R.; Sinclair, M.B.; Capolino, F.; Brener, I.

    2013-01-01

    The interaction between cavity modes and optical transitions leads to new coupled light-matter states in which the energy is periodically exchanged between the matter states and the optical mode. Here we present experimental evidence of optical strong coupling between modes of individual sub-wavelength metamaterial nanocavities and engineered optical transitions in semiconductor heterostructures. We show that this behaviour is generic by extending the results from the mid-infrared (~10 μm) to the near-infrared (~1.5 μm). Using mid-infrared structures, we demonstrate that the light-matter coupling occurs at the single resonator level and with extremely small interaction volumes. We calculate a mode volume of 4.9 × 10−4 (λ/n)3 from which we infer that only ~2,400 electrons per resonator participate in this energy exchange process. PMID:24287692

  18. Optical Activity Enhanced by Strong Inter-molecular Coupling in Planar Chiral Metamaterials

    PubMed Central

    Kim, Teun-Teun; Oh, Sang Soon; Park, Hyun-Sung; Zhao, Rongkuo; Kim, Seong-Han; Choi, Wonjune; Min, Bumki; Hess, Ortwin

    2014-01-01

    The polarization of light can be rotated in materials with an absence of molecular or structural mirror symmetry. While this rotating ability is normally rather weak in naturally occurring chiral materials, artificial chiral metamaterials have demonstrated extraordinary rotational ability by engineering intra-molecular couplings. However, while in general, chiral metamaterials can exhibit strong rotatory power at or around resonances, they convert linearly polarized waves into elliptically polarized ones. Here, we demonstrate that strong inter-molecular coupling through a small gap between adjacent chiral metamolecules can lead to a broadband enhanced rotating ability with pure rotation of linearly polarized electromagnetic waves. Strong inter-molecular coupling leads to nearly identical behaviour in magnitude, but engenders substantial difference in phase between transmitted left and right-handed waves. PMID:25209452

  19. Emergent patterns in space and time from daisyworld: a simple evolving coupled biosphere-climate model.

    PubMed

    Ackland, Graeme J; Wood, A Jamie

    2010-01-13

    We present a simplified model of a coupled planetary geosphere-biosphere, with two evolving species coupled through a single enviromental variable. The species do not compete directly, but instead compete through, and can evolve their effect on, this environmental parameter. The model produces an evolutionary arms race, with each species evolving extreme behaviour to counteract the other. The result is an apparently stable balance, with the planet supporting a maximum amount of life, in unusually patterned configurations. However, this balance is achieved by two countering effects and is susceptible to very large correlated fluctuations and extinction events if the balance is disturbed. This arms-race evolution is observed even for very small differences between the species: for a coupled evolving system, the 'neutral' theory of identical species is not the limiting case. PMID:19948549

  20. Oxidative stress, activity behaviour and body mass in captive parrots.

    PubMed

    Larcombe, S D; Tregaskes, C A; Coffey, J; Stevenson, A E; Alexander, L G; Arnold, K E

    2015-01-01

    Many parrot species are kept in captivity for conservation, but often show poor reproduction, health and survival. These traits are known to be influenced by oxidative stress, the imbalance between the production of reactive oxygen species (ROS) and ability of antioxidant defences to ameliorate ROS damage. In humans, oxidative stress is linked with obesity, lack of exercise and poor nutrition, all of which are common in captive animals. Here, we tested whether small parrots (budgerigars, Melopsittacus undulatus) maintained in typical pet cages and on ad libitum food varied in oxidative profile, behaviour and body mass. Importantly, as with many birds held in captivity, they did not have enough space to engage in extensive free flight. Four types of oxidative damage, single-stranded DNA breaks (low-pH comet assay), alkali-labile sites in DNA (high-pH comet assay), sensitivity of DNA to ROS (H2O2-treated comet assay) and malondialdehyde (a byproduct of lipid peroxidation), were uncorrelated with each other and with plasma concentrations of dietary antioxidants. Without strenuous exercise over 28 days in a relatively small cage, more naturally 'active' individuals had more single-stranded DNA breaks than sedentary birds. High body mass at the start or end of the experiment, coupled with substantial mass gain, were all associated with raised sensitivity of DNA to ROS. Thus, high body mass in these captive birds was associated with oxidative damage. These birds were not lacking dietary antioxidants, because final body mass was positively related to plasma levels of retinol, zeaxanthin and α-tocopherol. Individuals varied widely in activity levels, feeding behaviour, mass gain and oxidative profile despite standardized living conditions. DNA damage is often associated with poor immunocompetence, low fertility and faster ageing. Thus, we have candidate mechanisms for the limited lifespan and fecundity common to many birds kept for conservation purposes. PMID:27293729

  1. Oxidative stress, activity behaviour and body mass in captive parrots

    PubMed Central

    Larcombe, S. D.; Tregaskes, C. A.; Coffey, J.; Stevenson, A. E.; Alexander, L. G.; Arnold, K. E.

    2015-01-01

    Many parrot species are kept in captivity for conservation, but often show poor reproduction, health and survival. These traits are known to be influenced by oxidative stress, the imbalance between the production of reactive oxygen species (ROS) and ability of antioxidant defences to ameliorate ROS damage. In humans, oxidative stress is linked with obesity, lack of exercise and poor nutrition, all of which are common in captive animals. Here, we tested whether small parrots (budgerigars, Melopsittacus undulatus) maintained in typical pet cages and on ad libitum food varied in oxidative profile, behaviour and body mass. Importantly, as with many birds held in captivity, they did not have enough space to engage in extensive free flight. Four types of oxidative damage, single-stranded DNA breaks (low-pH comet assay), alkali-labile sites in DNA (high-pH comet assay), sensitivity of DNA to ROS (H2O2-treated comet assay) and malondialdehyde (a byproduct of lipid peroxidation), were uncorrelated with each other and with plasma concentrations of dietary antioxidants. Without strenuous exercise over 28 days in a relatively small cage, more naturally ‘active’ individuals had more single-stranded DNA breaks than sedentary birds. High body mass at the start or end of the experiment, coupled with substantial mass gain, were all associated with raised sensitivity of DNA to ROS. Thus, high body mass in these captive birds was associated with oxidative damage. These birds were not lacking dietary antioxidants, because final body mass was positively related to plasma levels of retinol, zeaxanthin and α-tocopherol. Individuals varied widely in activity levels, feeding behaviour, mass gain and oxidative profile despite standardized living conditions. DNA damage is often associated with poor immunocompetence, low fertility and faster ageing. Thus, we have candidate mechanisms for the limited lifespan and fecundity common to many birds kept for conservation purposes. PMID

  2. 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

  3. 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

  4. 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

  5. Measuring the Shear-Tension Coupling of Engineering Fabrics

    SciTech Connect

    Abdiwi, F.; Harrison, P.; Guo, Z.; Yu, W. R.; Potluri, P.

    2011-05-04

    Modelling the forming process of engineering fabrics and textile composites using a mechanical approach, such as FEM, requires characterisation of material behaviour. Using Picture Frame (PF) tests, several previous studies have reported a coupling between in-plane tension and fabric shear compliance. However, characterising this behaviour accurately has proven problematic due to the sensitivity of the PF test to small fabric misalignments in the test rig, prompting innovative solutions such as the use of load-cells mounted on the side bars of the PF rig to measure in-plane tension during testing. This paper focuses on an alternative testing technique, the Biaxial Bias Extension test, as a means to investigate this coupling. The approach has several benefits including simple equipment requirements, the ability to vary sample dimensions and boundary conditions. The main difficulty lies in extracting the material contribution to the recorded signal. To do this, an experimental method is demonstrated using two very different textiles; glass fabric and self-reinforced polypropylene both plain weaves. The latter is challenging to characterise and was chosen due to its high propensity to wrinkle at room temperature.

  6. Measuring the Shear-Tension Coupling of Engineering Fabrics

    NASA Astrophysics Data System (ADS)

    Abdiwi, F.; Harrison, P.; Guo, Z.; Potluri, P.; Yu, W. R.

    2011-05-01

    Modelling the forming process of engineering fabrics and textile composites using a mechanical approach, such as FEM, requires characterisation of material behaviour. Using Picture Frame (PF) tests, several previous studies have reported a coupling between in-plane tension and fabric shear compliance. However, characterising this behaviour accurately has proven problematic due to the sensitivity of the PF test to small fabric misalignments in the test rig, prompting innovative solutions such as the use of load-cells mounted on the side bars of the PF rig to measure in-plane tension during testing. This paper focuses on an alternative testing technique, the Biaxial Bias Extension test, as a means to investigate this coupling. The approach has several benefits including simple equipment requirements, the ability to vary sample dimensions and boundary conditions. The main difficulty lies in extracting the material contribution to the recorded signal. To do this, an experimental method is demonstrated using two very different textiles; glass fabric and self-reinforced polypropylene both plain weaves. The latter is challenging to characterise and was chosen due to its high propensity to wrinkle at room temperature.

  7. 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.

  8. Evanescent coupling between surface and linear-defect guided modes in phononic crystals

    NASA Astrophysics Data System (ADS)

    Cicek, Ahmet; Salman, Aysevil; Adem Kaya, Olgun; Ulug, Bulent

    2016-01-01

    Evanescent coupling between surface and linear-defect waveguide modes in a two-dimensional phononic crystal of steel cylinders in air is numerically demonstrated. When the ratio of scatterer radii to the lattice constant is set to 0.47 in the square phononic crystal, the two types of modes start interacting if there is one-row separation between the surface and waveguide. Supercell band structure computations through the Finite Element Method suggest that the waveguide band is displaced significantly, whereas the surface band remains almost intact when the waveguide and surface are in close proximity. The two resultant hybrid bands are such that the coupling length, which varies between 8 and 22 periods, initially changes linearly with frequency, while a much sharper variation is observed towards the top of the lower hybrid band. Such small values facilitate the design of compact devices based on heterogeneous coupling. Finite-element simulations demonstrate bilateral coupling behaviour, where waves incident from either the surface or waveguide can efficiently couple to the other side. The coupling lengths calculated from simulation results are in agreement with the values predicted from the supercell band structure. The possible utilisation of the coupling scheme in sensing applications, especially in acoustic Doppler velocimetry, is discussed.

  9. Auto-Graph: Considering the Utility of Student Behaviour Self-Monitoring for Inclusive Schools

    ERIC Educational Resources Information Center

    Jull, Stephen K.

    2006-01-01

    This paper reports the outcomes of a small-scale exploratory study that examined the utility of a novel computer-supported student behaviour self-monitoring procedure called Auto-Graph. The Auto-Graph procedure is a universal classroom behaviour management strategy for responding to disruptive antisocial behaviours. It was designed to provide…

  10. 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

  11. 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.

  12. 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.'

  13. Coupled translation-rotation eigenstates of H2, HD, and D2 in the large cage of structure II clathrate hydrate: comparison with the small cage and rotational Raman spectroscopy.

    PubMed

    Xu, Minzhong; Sebastianelli, Francesco; Bacić, Zlatko

    2009-07-01

    We report fully coupled quantum five-dimensional calculations of the translation-rotation (T-R) energy levels of one H(2), HD, and D(2) molecule confined inside the large hexakaidecahedral (5(12)6(4)) cage of the structure II clathrate hydrate. Highly converged T-R eigenstates have been obtained for excitation energies beyond the j = 2 rotational levels of the guest molecules, in order to allow comparison with the recent Raman spectroscopic measurements. The translationally excited T-R states are assigned with the quantum numbers n and l of the 3D isotropic harmonic oscillator. However, the translational excitations are not harmonic, since the level energies depend not only on n but also on l. For l > 1, the T-R levels having the same n,l values are split into groups of almost degenerate levels. The splitting patterns follow the predictions of group theory for the environment of T(d) symmetry, which is created by the configuration of the oxygen atoms of the large cage. The 2j + 1 degeneracy of the j = 1 and 2 rotational levels of the encapsulated hydrogen molecule is lifted entirely by the angular anisotropy of the H(2)-cage interaction potential. The patterns and magnitudes of the j = 1, 2 rotational level splittings, and the energies of the sublevels, in the large cage are virtually identical with those calculated for the small cage. This is in agreement with, and sheds light on, the observation that the S(0)(0) (j = 0-->2) bands in the rotational Raman spectra measured for simple H(2) hydrate and the binary hydrate of H(2) with tetrahydrofuran are remarkably similar with respect to their frequencies, widths, shapes, and internal structure, when the H(2) occupancy of the large cage of simple H(2) hydrate is low. PMID:19552479

  14. 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

  15. 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

  16. Running coupling corrections to inclusive gluon production

    NASA Astrophysics Data System (ADS)

    Horowitz, W. A.; Kovchegov, Y. V.

    2011-12-01

    We calculate running coupling corrections for the lowest-order gluon production cross section in high energy hadronic and nuclear scattering using the BLM scale-setting prescription. At leading order, there are three powers of fixed coupling; in our final answer, these three couplings are replaced by seven factors of running coupling: five in the numerator and two in the denominator, forming a 'septumvirate' of running couplings, analogous to the 'triumvirate' of running couplings found earlier for the small-x BFKL/BK/JIMWLK evolution equations. It is interesting to note that the two running couplings in the denominator of the 'septumvirate' run with complex-valued momentum scales, which are complex conjugates of each other, such that the production cross section is indeed real. We use our lowest-order result to conjecture how running coupling corrections may enter the full fixed-coupling kT-factorization formula for gluon production which includes nonlinear small-x evolution.

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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.

  2. 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)

  3. A Few Bad Apples: A Model of Disease Influenced Agent Behaviour in a Heterogeneous Contact Environment

    PubMed Central

    Enright, Jessica; Kao, Rowland R.

    2015-01-01

    For diseases that infect humans or livestock, transmission dynamics are at least partially dependent on human activity and therefore human behaviour. However, the impact of human behaviour on disease transmission is relatively understudied, especially in the context of heterogeneous contact structures such as described by a social network. Here, we use a strategic game, coupled with a simple disease model, to investigate how strategic agent choices impact the spread of disease over a contact network. Using beliefs that are based on disease status and that build up over time, agents choose actions that stochastically determine disease spread on the network. An agent’s disease status is therefore a function of both his own and his neighbours actions. The effect of disease on agents is modelled by a heterogeneous payoff structure. We find that the combination of network shape and distribution of payoffs has a non-trivial impact on disease prevalence, even if the mean payoff remains the same. An important scenario occurs when a small percentage (called noncooperators) have little incentive to avoid disease. For diseases that are easily acquired when taking a risk, then even when good behavior can lead to disease eradication, a small increase in the percentage of noncooperators (less than 5%) can yield a large (up to 25%) increase in prevalence. PMID:25734661

  4. A few bad apples: a model of disease influenced agent behaviour in a heterogeneous contact environment.

    PubMed

    Enright, Jessica; Kao, Rowland R

    2015-01-01

    For diseases that infect humans or livestock, transmission dynamics are at least partially dependent on human activity and therefore human behaviour. However, the impact of human behaviour on disease transmission is relatively understudied, especially in the context of heterogeneous contact structures such as described by a social network. Here, we use a strategic game, coupled with a simple disease model, to investigate how strategic agent choices impact the spread of disease over a contact network. Using beliefs that are based on disease status and that build up over time, agents choose actions that stochastically determine disease spread on the network. An agent's disease status is therefore a function of both his own and his neighbours actions. The effect of disease on agents is modelled by a heterogeneous payoff structure. We find that the combination of network shape and distribution of payoffs has a non-trivial impact on disease prevalence, even if the mean payoff remains the same. An important scenario occurs when a small percentage (called noncooperators) have little incentive to avoid disease. For diseases that are easily acquired when taking a risk, then even when good behavior can lead to disease eradication, a small increase in the percentage of noncooperators (less than 5%) can yield a large (up to 25%) increase in prevalence. PMID:25734661

  5. 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.

  6. 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…

  7. 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

  8. 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.

  9. 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

  10. Mapping the stereotyped behaviour of freely moving fruit flies

    PubMed Central

    Berman, Gordon J.; Choi, Daniel M.; Bialek, William; Shaevitz, Joshua W.

    2014-01-01

    A frequent assumption in behavioural science is that most of an animal's activities can be described in terms of a small set of stereotyped motifs. Here, we introduce a method for mapping an animal's actions, relying only upon the underlying structure of postural movement data to organize and classify behaviours. Applying this method to the ground-based behaviour of the fruit fly, Drosophila melanogaster, we find that flies perform stereotyped actions roughly 50% of the time, discovering over 100 distinguishable, stereotyped behavioural states. These include multiple modes of locomotion and grooming. We use the resulting measurements as the basis for identifying subtle sex-specific behavioural differences and revealing the low-dimensional nature of animal motions. PMID:25142523

  11. Mapping the stereotyped behaviour of freely moving fruit flies.

    PubMed

    Berman, Gordon J; Choi, Daniel M; Bialek, William; Shaevitz, Joshua W

    2014-10-01

    A frequent assumption in behavioural science is that most of an animal's activities can be described in terms of a small set of stereotyped motifs. Here, we introduce a method for mapping an animal's actions, relying only upon the underlying structure of postural movement data to organize and classify behaviours. Applying this method to the ground-based behaviour of the fruit fly, Drosophila melanogaster, we find that flies perform stereotyped actions roughly 50% of the time, discovering over 100 distinguishable, stereotyped behavioural states. These include multiple modes of locomotion and grooming. We use the resulting measurements as the basis for identifying subtle sex-specific behavioural differences and revealing the low-dimensional nature of animal motions. PMID:25142523

  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. 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

  1. 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

  2. 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.

  3. Microwave interconnects via electromagnetic coupling

    NASA Astrophysics Data System (ADS)

    Burke, John J.; Jackson, Robert W.

    1988-01-01

    Two transitions are described which couple coplanar waveguide on one substrate surface (a motherboard) to either coplanar waveguide or microstrip on another substrate surface (a chip). No wire bonds are necessary. A coupled transmission line model, along with a full wave analysis, is used to predict the behavior of these transitions. Experimental results show good agreement with predictions in cases where the coupler length to width ratio is not too small.

  4. The transitional behaviour of avalanches in cohesive granular materials

    NASA Astrophysics Data System (ADS)

    Quintanilla, M. A. S.; Valverde, J. M.; Castellanos, A.

    2006-07-01

    We present a statistical analysis of avalanches of granular materials that partially fill a slowly rotated horizontal drum. For large sized noncohesive grains the classical coherent oscillation is reproduced, consisting of a quasi-periodic succession of regularly sized avalanches. As the powder cohesiveness is increased by decreasing the particle size, we observe a gradual crossover to a complex dynamics that resembles the transitional behaviour observed in fusion plasmas. For particle size below ~50 µm, avalanches lose a characteristic size, retain a short term memory and turn gradually decorrelated in the long term as described by a Markov process. In contrast, large grains made cohesive by coating them with adhesive microparticles display a distinct phenomenology, characterized by a quasi-regular succession of well defined small precursors and large relaxation events. The transition from a one-peaked distribution (noncohesive large beads) to a flattened distribution (fine cohesive beads) passing through the two-peaked distribution of cohesive large beads had already been predicted using a coupled-map lattice model, as the relaxation mechanism of grain reorganization becomes dominant to the detriment of inertia.

  5. 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.

  6. 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

  7. The attitudes of nurse tutor students to behavioural objectives: results and discussion.

    PubMed

    Martin, H; Sheehan, J

    1985-05-01

    This small-scale empirical study provides evidence of the attitudes of a group of nurse tutor students to behavioural objectives. The questionnaire items used ranged from questions about behaviourism and the use of behavioural objectives in teaching, to a question on whether the participants would use behavioural objectives in their teaching once they had finished their course. It emerged that while there was not an uncritical acceptance of behavioural objectives, they were seen as having a place in the process of teaching and learning nursing. PMID:3848452

  8. Universal J-coupling prediction.

    PubMed

    Lehtivarjo, Juuso; Niemitz, Matthias; Korhonen, Samuli-Petrus

    2014-03-24

    A data driven approach for small molecule J-coupling prediction is presented. The method is targeted for use as part of an automatic spectrum analysis, therefore emphasizing prediction coverage, maintainability, and speed in the design. The database search involves encoding the coupling path atom types into hash codes, which are used to retrieve the matching coupling constant entries from the database. The fast hash dictionary search is followed by a k Nearest Neighbors regression to resolve the substituent and conformational dependencies, parametrized with atomic charges, torsion angles, and steric bulk. PMID:24593659

  9. 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,…

  10. 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.

  11. Rheological (visco-elastic behaviour) analysis of cyclic olefin copolymers with application to hot embossing for microfabrication

    NASA Astrophysics Data System (ADS)

    Jena, R. K.; Chen, X.; Yue, C. Y.; Lam, Y. C.

    2011-08-01

    Transparent, amorphous cyclic olefin copolymers (COCs) have been frequently used for the fabrication of microfluidic devices using a hot embossing technique for numerous applications. In hot embossing, the polymer is deformed near its glass transition temperature (Tg), i.e. between Tg and Tg + 60 °C where the viscoelastic properties of the material are dominant. The proper characterization of the viscoelastic properties is of interest as this can lead to a better understanding of polymer flow behaviour during microfabrication. Furthermore, the ability to model its rheological behaviour will enable the prediction of the optimal hot embossing processing parameters. We performed small amplitude oscillatory shear experiments on four grades of COCs, TOPAS-8007, TOPAS-5013, TOPAS-6015 and TOPAS-6017, in order to characterize their flow behaviour. The experiments were conducted within the frequency range from 0.01 to 500 Hz at between Tg + 20 and Tg + 60 °C. The flow properties could be represented using a generalized Maxwell viscoelastic constitutive model with Williams-Landel-Ferry-type temperature dependence. Good fit of the experimental data was obtained over a wide range of temperatures. The model could be coupled with ABAQUS finite element software to predict the optimal conditions for fabricating a capillary electrophoresis micro-chip on a TOPAS-5013 substrate by hot embossing.

  12. 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.

  13. 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

  14. Three-spined sticklebacks Gasterosteus aculeatus as a model for exploring behavioural biology.

    PubMed

    Huntingford, F A; Ruiz-Gomez, M L

    2009-11-01

    Niko Tinbergen chose the three-spined stickleback Gasterosteus aculeatus for his classic behavioural studies because they are small, robust, common and easy to house in the laboratory under reasonably natural conditions and also because their behaviour, while sufficiently simple to be tractable, is still sufficiently complex to be interesting. An analysis of citation records shows that this was an inspired choice. Research on these small fish has addressed all four of Tinbergen's famous questions (causation, development, functions and evolution) and has contributed to the understanding of many different behavioural systems. The G. aculeatus literature is used here to explore several themes in fundamental behavioural biology (diet choice, shoaling, behavioural syndromes and sexual signalling) and the extent to which research using G. aculeatus has informed both fundamental and applied behavioural biology, the latter in the context of aquaculture research. PMID:20738667

  15. Spin-orbit-coupled quantum gases

    NASA Astrophysics Data System (ADS)

    Radic, Juraj

    The dissertation explores the effects of synthetic spin-orbit coupling on the behaviour of quantum gases in several different contexts. We first study realistic methods to create vortices in spin-orbit-coupled (SOC) Bose-Einstein condensates (BEC). We propose two different methods to induce thermodynamically stable static vortex configurations: (1) to rotate both the Raman lasers and the anisotropic trap; and (2) to impose a synthetic Abelian field on top of synthetic spin-orbit interactions. We solve the Gross-Pitaevskii equation for several experimentally relevant regimes and find new interesting effects such as spatial separation of left- and right-moving spin-orbit-coupled condensates, and the appearance of unusual vortex arrangements. Next we consider cold atoms in an optical lattice with synthetic SOC in the Mott-insulator regime. We calculate the parameters of the corresponding tight-binding model and derive the low-energy spin Hamiltonian which is a combination of Heisenberg model, quantum compass model and Dzyaloshinskii-Moriya interaction. We find that the Hamiltonian supports a rich classical phase diagram with collinear, spiral and vortex phases. Next we study the time evolution of the magnetization in a Rashba spin-orbit-coupled Fermi gas, starting from a fully-polarized initial state. We model the dynamics using a Boltzmann equation, which we solve in the Hartree-Fock approximation. The resulting non-linear system of equations gives rise to three distinct dynamical regimes controlled by the ratio of interaction and spin-orbit-coupling strength lambda: for small lambda, the magnetization decays to zero. For intermediate lambda, it displays undamped oscillations about zero and for large lambda, a partially magnetized state is dynamically stabilized. Motivated by an interesting stripe phase which appears in BEC with SOC [Li et al., Phys. Rev. Lett. 108, 225301 (2011)], we study the finite-temperature phase diagram of a pseudospin-1/2 Bose gas with

  16. Controlling interneuron activity in Caenorhabditis elegans to evoke chemotactic behaviour.

    PubMed

    Kocabas, Askin; Shen, Ching-Han; Guo, Zengcai V; Ramanathan, Sharad

    2012-10-11

    Animals locate and track chemoattractive gradients in the environment to find food. With its small nervous system, Caenorhabditis elegans is a good model system in which to understand how the dynamics of neural activity control this search behaviour. Extensive work on the nematode has identified the neurons that are necessary for the different locomotory behaviours underlying chemotaxis through the use of laser ablation, activity recording in immobilized animals and the study of mutants. However, we do not know the neural activity patterns in C. elegans that are sufficient to control its complex chemotactic behaviour. To understand how the activity in its interneurons coordinate different motor programs to lead the animal to food, here we used optogenetics and new optical tools to manipulate neural activity directly in freely moving animals to evoke chemotactic behaviour. By deducing the classes of activity patterns triggered during chemotaxis and exciting individual neurons with these patterns, we identified interneurons that control the essential locomotory programs for this behaviour. Notably, we discovered that controlling the dynamics of activity in just one interneuron pair (AIY) was sufficient to force the animal to locate, turn towards and track virtual light gradients. Two distinct activity patterns triggered in AIY as the animal moved through the gradient controlled reversals and gradual turns to drive chemotactic behaviour. Because AIY neurons are post-synaptic to most chemosensory and thermosensory neurons, it is probable that these activity patterns in AIY have an important role in controlling and coordinating different taxis behaviours of the animal. PMID:23000898

  17. 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

  18. Driver behaviour at roadworks.

    PubMed

    Walker, Guy; Calvert, Malcolm

    2015-11-01

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

  19. 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

  20. Small Wins.

    ERIC Educational Resources Information Center

    Rhatigan, James J.; Schuh, John H.

    2003-01-01

    Examines how it easy for people to overlook small successes when they are overwhelmed by and preoccupied with large projects and goals. Explores the concept of "small wins" in organizational theory, which have the potential to become a prominent part of institutional culture and impact organizational behavior and change. (GCP)

  1. 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

  2. High-brightness organic light-emitting diodes for optogenetic control of Drosophila locomotor behaviour

    PubMed Central

    Morton, Andrew; Murawski, Caroline; Pulver, Stefan R.; Gather, Malte C.

    2016-01-01

    Organic light emitting diodes (OLEDs) are in widespread use in today’s mobile phones and are likely to drive the next generation of large area displays and solid-state lighting. Here we show steps towards their utility as a platform technology for biophotonics, by demonstrating devices capable of optically controlling behaviour in live animals. Using devices with a pin OLED architecture, sufficient illumination intensity (0.3 mW.mm−2) to activate channelrhodopsins (ChRs) in vivo was reliably achieved at low operating voltages (5 V). In Drosophila melanogaster third instar larvae expressing ChR2(H134R) in motor neurons, we found that pulsed illumination from blue and green OLEDs triggered robust and reversible contractions in animals. This response was temporally coupled to the timing of OLED illumination. With blue OLED illumination, the initial rate and overall size of the behavioural response was strongest. Green OLEDs achieved roughly 70% of the response observed with blue OLEDs. Orange OLEDs did not produce contractions in larvae, in agreement with the spectral response of ChR2(H134R). The device configuration presented here could be modified to accommodate other small model organisms, cell cultures or tissue slices and the ability of OLEDs to provide patterned illumination and spectral tuning can further broaden their utility in optogenetics experiments. PMID:27484401

  3. High-brightness organic light-emitting diodes for optogenetic control of Drosophila locomotor behaviour

    NASA Astrophysics Data System (ADS)

    Morton, Andrew; Murawski, Caroline; Pulver, Stefan R.; Gather, Malte C.

    2016-08-01

    Organic light emitting diodes (OLEDs) are in widespread use in today’s mobile phones and are likely to drive the next generation of large area displays and solid-state lighting. Here we show steps towards their utility as a platform technology for biophotonics, by demonstrating devices capable of optically controlling behaviour in live animals. Using devices with a pin OLED architecture, sufficient illumination intensity (0.3 mW.mm‑2) to activate channelrhodopsins (ChRs) in vivo was reliably achieved at low operating voltages (5 V). In Drosophila melanogaster third instar larvae expressing ChR2(H134R) in motor neurons, we found that pulsed illumination from blue and green OLEDs triggered robust and reversible contractions in animals. This response was temporally coupled to the timing of OLED illumination. With blue OLED illumination, the initial rate and overall size of the behavioural response was strongest. Green OLEDs achieved roughly 70% of the response observed with blue OLEDs. Orange OLEDs did not produce contractions in larvae, in agreement with the spectral response of ChR2(H134R). The device configuration presented here could be modified to accommodate other small model organisms, cell cultures or tissue slices and the ability of OLEDs to provide patterned illumination and spectral tuning can further broaden their utility in optogenetics experiments.

  4. High-brightness organic light-emitting diodes for optogenetic control of Drosophila locomotor behaviour.

    PubMed

    Morton, Andrew; Murawski, Caroline; Pulver, Stefan R; Gather, Malte C

    2016-01-01

    Organic light emitting diodes (OLEDs) are in widespread use in today's mobile phones and are likely to drive the next generation of large area displays and solid-state lighting. Here we show steps towards their utility as a platform technology for biophotonics, by demonstrating devices capable of optically controlling behaviour in live animals. Using devices with a pin OLED architecture, sufficient illumination intensity (0.3 mW.mm(-2)) to activate channelrhodopsins (ChRs) in vivo was reliably achieved at low operating voltages (5 V). In Drosophila melanogaster third instar larvae expressing ChR2(H134R) in motor neurons, we found that pulsed illumination from blue and green OLEDs triggered robust and reversible contractions in animals. This response was temporally coupled to the timing of OLED illumination. With blue OLED illumination, the initial rate and overall size of the behavioural response was strongest. Green OLEDs achieved roughly 70% of the response observed with blue OLEDs. Orange OLEDs did not produce contractions in larvae, in agreement with the spectral response of ChR2(H134R). The device configuration presented here could be modified to accommodate other small model organisms, cell cultures or tissue slices and the ability of OLEDs to provide patterned illumination and spectral tuning can further broaden their utility in optogenetics experiments. PMID:27484401

  5. Small Animal Retinal Imaging

    NASA Astrophysics Data System (ADS)

    Choi, WooJhon; Drexler, Wolfgang; Fujimoto, James G.

    Developing and validating new techniques and methods for small animal imaging is an important research area because there are many small animal models of retinal diseases such as diabetic retinopathy, age-related macular degeneration, and glaucoma [1-6]. Because the retina is a multilayered structure with distinct abnormalities occurring in different intraretinal layers at different stages of disease progression, there is a need for imaging techniques that enable visualization of these layers individually at different time points. Although postmortem histology and ultrastructural analysis can be performed for investigating microscopic changes in the retina in small animal models, this requires sacrificing animals, which makes repeated assessment of the same animal at different time points impossible and increases the number of animals required. Furthermore, some retinal processes such as neurovascular coupling cannot be fully characterized postmortem.

  6. 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,…

  7. Overdamping by weakly coupled environments

    NASA Astrophysics Data System (ADS)

    Esposito, Massimiliano; Haake, Fritz

    2005-12-01

    A quantum system weakly interacting with a fast environment usually undergoes a relaxation with complex frequencies whose imaginary parts are damping rates quadratic in the coupling to the environment in accord with Fermi’s “golden rule.” We show for various models (spin damped by harmonic-oscillator or random-matrix baths, quantum diffusion, and quantum Brownian motion) that upon increasing the coupling up to a critical value still small enough to allow for weak-coupling Markovian master equations, a different relaxation regime can occur. In that regime, complex frequencies lose their real parts such that the process becomes overdamped. Our results call into question the standard belief that overdamping is exclusively a strong coupling feature.

  8. Overdamping by weakly coupled environments

    SciTech Connect

    Esposito, Massimiliano; Haake, Fritz

    2005-12-15

    A quantum system weakly interacting with a fast environment usually undergoes a relaxation with complex frequencies whose imaginary parts are damping rates quadratic in the coupling to the environment in accord with Fermi's 'golden rule'. We show for various models (spin damped by harmonic-oscillator or random-matrix baths, quantum diffusion, and quantum Brownian motion) that upon increasing the coupling up to a critical value still small enough to allow for weak-coupling Markovian master equations, a different relaxation regime can occur. In that regime, complex frequencies lose their real parts such that the process becomes overdamped. Our results call into question the standard belief that overdamping is exclusively a strong coupling feature.

  9. 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

  10. GENERAL: Complete and phase synchronization in a heterogeneous small-world neuronal network

    NASA Astrophysics Data System (ADS)

    Han, Fang; Lu, Qi-Shao; Wiercigroch, Marian; Ji, Quan-Bao

    2009-02-01

    Synchronous firing of neurons is thought to be important for information communication in neuronal networks. This paper investigates the complete and phase synchronization in a heterogeneous small-world chaotic Hindmarsh-Rose neuronal network. The effects of various network parameters on synchronization behaviour are discussed with some biological explanations. Complete synchronization of small-world neuronal networks is studied theoretically by the master stability function method. It is shown that the coupling strength necessary for complete or phase synchronization decreases with the neuron number, the node degree and the connection density are increased. The effect of heterogeneity of neuronal networks is also considered and it is found that the network heterogeneity has an adverse effect on synchrony.

  11. Saying Goodbye: An Investigation into Parent-Infant Separation Behaviours on Arrival in Childcare

    ERIC Educational Resources Information Center

    Jovanovic, Jessie

    2011-01-01

    The goal of this small-scale study was to investigate how parental separation behaviours affect the transitional behaviour of infants aged 6-18 months. Thirty parent-infant pairs were observed during the separation process across three metropolitan childcare centres in Adelaide, South Australia. Observed interactions with both their infants and…

  12. Effects of an Emotional Literacy Intervention for Students Identified with Bullying Behaviour

    ERIC Educational Resources Information Center

    Knowler, Claire; Frederickson, Norah

    2013-01-01

    The effectiveness of a 12-week, small group emotional literacy (EL) intervention in reducing bullying behaviour in school was evaluated. Participants were 50 primary school pupils identified through peer nomination as engaging in bullying behaviours. The intervention was implemented in schools already engaged with a universal social and emotional…

  13. Supporting Positive Behaviour in Alberta Schools: An Intensive Individualized Approach

    ERIC Educational Resources Information Center

    Souveny, Dwaine

    2008-01-01

    Drawing on current research and best practices, this third part of the three-part resource, "Supporting Positive Behaviour in Alberta Schools," provides information and strategies for providing intensive, individualized support and instruction for the small percentage of students requiring a high degree of intervention. This system of individual…

  14. Harmonic and Anharmonic Behaviour of a Simple Oscillator

    ERIC Educational Resources Information Center

    O'Shea, Michael J.

    2009-01-01

    We consider a simple oscillator that exhibits harmonic and anharmonic regimes and analyse its behaviour over the complete range of possible amplitudes. The oscillator consists of a mass "m" fixed at the midpoint of a horizontal rope. For zero initial rope tension and small amplitude the period of oscillation, tau, varies as tau is approximately…

  15. Characterization of the phase behaviour of a novel polymerizable lyotropic ionic liquid crystal.

    PubMed

    Goujon, Nicolas; Forsyth, Maria; Dumée, Ludovic F; Bryant, Gary; Byrne, Nolene

    2015-09-21

    The development of new polymerizable lyotropic liquid crystals (LLCs) utilizing charged amphiphilic molecules such as those based on long chain imidazolium compounds, is a relatively new design direction for producing robust membranes with controllable nano-structures. Here we have developed a novel polymerizable ionic liquid based LLC, 1-hexadecyl-3-methylimidazolium acrylate (C16mimAcr), where the acrylate anion acts as the polymerizable moiety. The phase behaviour of the C16mimAcr upon the addition of water was characterized using small and wide angle X-ray scatterings, differential scanning calorimetry and polarized optical microscopy. We compare the phase behaviour of this new polymerizable LLC to that of the well known LLC chloride analogue, 1-hexadecyl-3-methylimidazolium chloride (C16mimCl). We find that the C16mimAcr system has a more complex phase behaviour compared to the C16mimCl system. Additional lyotropic liquid crystalline mesophases such as hexagonal phase (H1) and discontinuous cubic phase (I1) are observed at 20 °C for the acrylate system at 50 and 65 wt% water respectively. The appearance of the hexagonal phase (H1) and discontinuous cubic phase (I1) for the acrylate system is likely due to the strong hydrating nature of the acrylate anion, which increases the head group area. The formation of these additional mesophases seen for the acrylate system, especially the hexagonal phase (H1), coupled with the polymerization functionality offers great potential in the design of advanced membrane materials with selective and anisotropic transport properties. PMID:26271610

  16. Contactless Coupling For Power And Data

    NASA Technical Reports Server (NTRS)

    Moody, John C.; Foley, Joseph W.

    1988-01-01

    Experimental flat-plate coupling transmits digital data signals and electrical power across small gap between two modules. Split transformer and optoelectronic components transmit electrical power and digital signals across small gap. Coupling concept useful substitute for electrical connectors in equipment assembled by robots, remote manipulators, or humans working in protective clothing or otherwise restricted in dexterity. Offers higher reliability due to one overall alignment mechanism as opposed to multiple pin/socket alignment requirements.

  17. 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…

  18. 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

  19. An exploration of coupled surface-subsurface solute transport in a fully integrated catchment model

    NASA Astrophysics Data System (ADS)

    Liggett, Jessica E.; Partington, Daniel; Frei, Sven; Werner, Adrian D.; Simmons, Craig T.; Fleckenstein, Jan H.

    2015-10-01

    Coupling surface and subsurface water flow in fully integrated hydrological codes is becoming common in hydrological research; however, the coupling of surface-subsurface solute transport has received much less attention. Previous studies on fully integrated solute transport focus on small scales, simple geometric domains, and have not utilised many different field data sources. The objective of this study is to demonstrate the inclusion of both flow and solute transport in a 3D, fully integrated catchment model, utilising high resolution observations of dissolved organic carbon (DOC) export from a wetland complex during a rainfall event. A sensitivity analysis is performed to span a range of transport conditions for the surface-subsurface boundary (e.g. advective exchange only, advection plus diffusion, advection plus full mechanical dispersion) and subsurface dispersivities. The catchment model captures some aspects of observed catchment behaviour (e.g. solute discharge at the catchment outlet, increasing discharge from wetlands with increased stream discharge, and counter-clockwise concentration-discharge relationships), although other known behaviours are not well represented in the model (e.g. slope of concentration-discharge plots). Including surface-subsurface solute transport aids in evaluating internal model processes, however there are challenges related to the influence of dispersion across the surface-subsurface interface, and non-uniqueness of the solute transport solution. This highlights that obtaining solute field data is especially important for constraining integrated models of solute transport.

  20. 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.

  1. Centropages behaviour: Swimming and vertical migration

    NASA Astrophysics Data System (ADS)

    Alcaraz, Miguel; Saiz, Enric; Calbet, Albert

    2007-02-01

    The evolutionary success of any species living in a variable environment depends on its capacity to enhance the probability of finding food and mates, and escaping predators. In the case of copepods of the genus Centropages, as in all planktonic copepods, their swimming behaviour is closely tied to these vital aspects, and shows a high degree of plasticity and adaptive capacity. Swimming mechanisms of Centropages change radically during development, mainly in the transition between naupliar stages to the 1st copepodite; nauplii do not produce feeding currents, whereas copepodites do. Adults and late developmental stages of C. typicus, C. hamatus and C. velificatus spend most of the time in slow swimming and resting breaks, with occasional and brief fast swimming (escape reactions) and grooming events. Slow swimming is closely related to the creation of feeding currents, and results from the beating of the cephalic appendages in a “fling and clap” manner. The proportion of time allocated to the different swimming activities depends on sensory cues like type and concentration of food, presence of potential mates, light intensity, hydrodynamic flow, etc. The responses of Centropages to changes in flow velocity fluctuations (small-scale turbulence) are similar to the escape responses (fast swimming) triggered by the presence of potential predators. Centropages generally have standard nocturnal vertical migration patterns involving considerable vertical displacements. This behaviour is closely related to the narrow spectral sensitivity and the low intensity threshold of the genus, and has important consequences for the active vertical transport of matter and energy. The variety of responses of Centropages to environmental changes, and in general all the aspects related to its swimming behaviour seem to be controlled by the trade-off between energetic gains (food intake), losses (swimming energy expenditure), and predation risk. Behavioural plasticity and adaptation

  2. 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

  3. 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

  4. 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

  5. Behaviour of magnetic Janus-like colloids

    NASA Astrophysics Data System (ADS)

    Novak, Ekaterina V.; Pyanzina, Elena S.; Kantorovich, Sofia S.

    2015-06-01

    We present a theoretical study of Janus-like magnetic particles at low temperature. To describe the basic features of the Janus-type magnetic colloids, we put forward a simple model of a spherical particle with a dipole moment shifted outwards from the centre and oriented perpendicular to the particle radius. Using direct calculations and molecular dynamics computer simulations, we investigate the ground states of small clusters and the behaviour of bigger systems at low temperature. In both cases the important parameter is the dipolar shift, which leads to different ground states and, as a consequence, to a different microscopic behaviour in the situation when the thermal fluctuations are finite. We show that the head-to-tail orientation of dipoles provides a two-particle energy minima only if the dipoles are not shifted from the particle centres. This is one of the key differences from the system of shifted dipolar particles (sd-particles), in which the dipole was shifted outwards radially, studied earlier (Kantorovich et al 2011 Soft Matter 7 5217-27). For sd-particles the dipole could be shifted out of the centre for almost 40% before the head-to-tail orientation was losing its energetic advantage. This peculiarity manifests itself in the topology of the small clusters in the ground state and in the response of the Janus-like particle systems to an external magnetic field at finite temperatures.

  6. Circuit electromechanics with single photon strong coupling

    SciTech Connect

    Xue, Zheng-Yuan Yang, Li-Na; Zhou, Jian

    2015-07-13

    In circuit electromechanics, the coupling strength is usually very small. Here, replacing the capacitor in circuit electromechanics by a superconducting flux qubit, we show that the coupling among the qubit and the two resonators can induce effective electromechanical coupling which can attain the strong coupling regime at the single photon level with feasible experimental parameters. We use dispersive couplings among two resonators and the qubit while the qubit is also driven by an external classical field. These couplings form a three-wave mixing configuration among the three elements where the qubit degree of freedom can be adiabatically eliminated, and thus results in the enhanced coupling between the two resonators. Therefore, our work constitutes the first step towards studying quantum nonlinear effect in circuit electromechanics.

  7. Small ethics.

    PubMed

    Chambers, David W

    2007-01-01

    Traditionally, ethics in the professions has focused on big problems that could be found on other peoples' back porches. Small, habitual, frequent, and personal lapses get little attention. In this essay, the literature on opportunism is applied to dentistry with a view toward bringing matters of "near ethics" within reach. Examples of small lapses are discussed under the headings of shirking, free riding, shrinkage, pressing, adverse selection, moral hazard, and risk shifting. The conditions that support opportunism include relationships with small numbers of transactions and uneven access to information. Practical limits on understanding all the consequences of agreements and the costs of supervising others and enforcing corrections of breaches are inescapable aspects of opportunism. Opportunism may not be accepted by all as the subject matter of ethical, but curbing it is a worthy goal and understanding the causes and management of opportunism casts some light on the ethical enterprise. Four suggestions are offered for addressing issue of opportunism. PMID:17691498

  8. Lightweight Restraint For Coupling Flanges

    NASA Technical Reports Server (NTRS)

    Whitaker, Willie D.

    1989-01-01

    End flanges of flexible coupling system restrained against excessive rotation or axial separation by inexpensive, lightweight mechanism based on cables and pulleys. Restraining mechanism adapted to cable, duct, hose, or passageway couplings between vehicles, or to other applications in which angular and positional misalignments must be restricted to moderate specified values. Total misalignment of two end flanges limited to amount of slack available in cable-and-pulley mechanism. When cable taut, further axial separation of flange centers restrained, but small tilts accommodated by running of cable through pulleys.

  9. Behavioural treatments for Tourette syndrome: an evidence-based review.

    PubMed

    Frank, Madeleine; Cavanna, Andrea Eugenio

    2013-01-01

    Tourette syndrome (TS) is a disorder characterised by multiple motor and vocal tics and is frequently associated with behavioural problems. Tics are known to be affected by internal factors such as inner tension and external factors such as the surrounding environment. A number of behavioural treatments have been suggested to treat the symptoms of TS, in addition to pharmacotherapy and surgery for the most severe cases. This review compiled all the studies investigating behavioural therapies for TS, briefly describing each technique and assessing the evidence in order to determine which of these appear to be effective. Different behavioural therapies that were used included habit reversal training (HRT), massed negative practice, supportive psychotherapy, exposure with response prevention, self-monitoring, cognitive-behavioural therapy, relaxation therapy, assertiveness training, contingency management, a tension-reduction technique and biofeedback training. Overall, HRT is the best-studied and most widely-used technique and there is sufficient experimental evidence to suggest that it is an effective treatment. Most of the other treatments, however, require further investigation to evaluate their efficacy. Specifically, evidence suggests that exposure with response prevention and self-monitoring are effective, and more research is needed to determine the therapeutic value of the other treatments. As most of the studies investigating behavioural treatments for TS are small-sample or single-case studies, larger randomised controlled trials are advocated. PMID:23187152

  10. 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

  11. Sexual Agreements among Gay Male Couples

    PubMed Central

    Hoff, Colleen H.; Beougher, Sean C.

    2009-01-01

    Many gay male couples make agreements about whether or not to permit sex with outside partners, yet little is known about the development and maintenance of these agreements, their impact on relationships, and whether they are an effective HIV prevention strategy. Using semi-structured, qualitative interviews, 39 gay male couples were asked about their sexual agreements and about other relationship dynamics that might affect their agreements. Analysis revealed a wide range of agreement types, all of which are presented along a continuum rather than as discrete categories. For couples with open agreements, most placed rules or conditions limiting when, where, how often, and with whom outside sex was permitted. Although motivations for having agreements varied, HIV prevention did not rank as a primary factor for any couple. Most couples had congruous agreements; however, a small number reported discrepancies which may increase HIV transmission risk. How couples handled breaks in their agreements also varied, depending on what condition was broken, whether it was disclosed, and the partner's reaction. Additional results include differences in agreement type and motivations for having an agreement based on couple serostatus. Overall, agreements benefited couples by providing boundaries for the relationship, supporting a non-heteronormative identity, and fulfilling the sexual needs of the couple. Future prevention efforts involving gay couples must address the range of agreement types and the meanings couples ascribe to them, in addition to tempering safety messages with the relationship issues that are important to and faced by gay couples. PMID:18686027

  12. 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

  13. 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

  14. 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

  15. The QCD running coupling

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

  16. Small obstacle avoidance sensor.

    PubMed

    Vollmerhausen, Richard H

    2013-01-01

    This paper describes a laser ranging sensor that is suitable for applications like small unmanned aerial vehicles. The hardware consists of a diode emitter array and line-scan charge coupled devices. A structured-light technique measures ranges up to 30 meters for 64 field angles in a 90 degree field of view. Operation is eye safe, and the laser wavelength is not visible to night vision goggles. This paper describes a specific sensor design in order to illustrate performance for a given package size. PMID:23878527

  17. 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

  18. Small Magnetometer

    NASA Technical Reports Server (NTRS)

    Kuhnke, Falko; Musmann, Gunter; Glassmeier, K. H.; Tsurutani, Bruce

    1995-01-01

    Small, lightweight, low-power magnetometer measures three-dimensional magnetic field. Includes three toroidal cores - one for each dimension. Exhibits high sensitivity, low zero-point drift, and low noise. Magnetometer circuit includes driver circuit and three analog signal-processing circuits. Output of analog signal-processing circuit proportional to one of components of external magnetic field.

  19. Nonequilibrium thermodynamics in the strong coupling and non-Markovian regime based on a reaction coordinate mapping

    NASA Astrophysics Data System (ADS)

    Strasberg, Philipp; Schaller, Gernot; Lambert, Neill; Brandes, Tobias

    2016-07-01

    We propose a method to study the thermodynamic behaviour of small systems beyond the weak coupling and Markovian approximation, which is different in spirit from conventional approaches. The idea is to redefine the system and environment such that the effective, redefined system is again coupled weakly to Markovian residual baths and thus, allows to derive a consistent thermodynamic framework for this new system–environment partition. To achieve this goal we make use of the reaction coordinate (RC) mapping, which is a general method in the sense that it can be applied to an arbitrary (quantum or classical and even time-dependent) system coupled linearly to an arbitrary number of harmonic oscillator reservoirs. The core of the method relies on an appropriate identification of a part of the environment (the RC), which is subsequently included as a part of the system. We demonstrate the power of this concept by showing that non-Markovian effects can significantly enhance the steady state efficiency of a three-level-maser heat engine, even in the regime of weak system–bath coupling. Furthermore, we show for a single electron transistor coupled to vibrations that our method allows one to justify master equations derived in a polaron transformed reference frame.

  20. 2012 Philip S. Portoghese Medicinal Chemistry Lectureship: Structure-Based Approaches to Ligands for G Protein-Coupled Adenosine and P2Y Receptors, From Small Molecules to Nanoconjugates +

    PubMed Central

    Jacobson, Kenneth A.

    Adenosine receptor (ARs) and P2Y receptors (P2YRs) that respond to extracellular nucleosides/tides are associated with new directions for therapeutics. The X-ray structures of the A 2A AR complexes with agonists and antagonists are examined in relationship to the G protein-coupled receptor (GPCR) superfamily and applied to drug discovery. Much of the data on AR ligand structure from early SAR studies, now is explainable from the A 2A AR X-ray crystallography. The ligand-receptor interactions in related GPCR complexes can be identified by means of modeling approaches, e.g. molecular docking. Thus, molecular recognition in binding and activation processes has been studied effectively using homology modeling and applied to ligand design. Virtual screening has yielded new nonnucleoside AR antagonists, and existing ligands have been improved with knowledge of the receptor interactions. New agonists are being explored for CNS and peripheral therapeutics based on in vivo activity, such as chronic neuropathic pain. Ligands for receptors more distantly related to the X-ray template, i.e. P2YRs, have been introduced and are mainly used as pharmacological tools for elucidating the physiological role of extracellular nucleotides. Other ligand tools for drug discovery include fluorescent probes, radioactive probes, multivalent probes, and functionalized nanoparticles. PMID:23597047

  1. Zebrafish (Danio rerio) behavioural response to bioinspired robotic fish and mosquitofish (Gambusia affinis).

    PubMed

    Polverino, Giovanni; Porfiri, Maurizio

    2013-12-01

    The field of ethorobotics holds promise in aiding fundamental research in animal behaviour, whereby it affords fully controllable and easily reproducible experimental tools. Most of the current ethorobotics studies are focused on the behavioural response of a selected target species as it interacts with a biologically-inspired robot in controlled laboratory conditions. In this work, we first explore the interactions between two social fish species and a robotic fish, whose design is inspired by salient visual features of one of the species. Specifically, this study investigates the behavioural response of small shoals of zebrafish interacting with a zebrafish-inspired robotic fish and small shoals of mosquitofish in a basic ecological context. Our results demonstrate that the robotic fish differentially influences the behaviour of the two species by consistently attracting zebrafish, while repelling mosquitofish. This selective behavioural control is successful in spatially isolating the two species, which would otherwise exhibit prey-predator interactions, with mosquitofish attacking zebrafish. PMID:23999758

  2. Simultaneous determination of N7-alkylguanines in DNA by isotope-dilution LC-tandem MS coupled with automated solid-phase extraction and its application to a small fish model

    PubMed Central

    Chao, Mu-Rong; Wang, Chien-Jen; Yen, Cheng-Chieh; Yang, Hsi-Hsien; Lu, Yao-Cheng; Chang, Louis W.; Hu, Chiung-Wen

    2006-01-01

    In the present study, we report the development of a sensitive and selective assay based on LC (liquid chromatography)–MS/MS (tandem MS) to simultaneously measure N7-MeG (N7-methylguanine) and N7-EtG (N7-ethylguanine) in DNA hydrolysates. With the use of isotope internal standards (15N5-N7-MeG and 15N5-N7-EtG) and on-line SPE (solid-phase extraction), the detection limit of this method was estimated as 0.42 fmol and 0.17 fmol for N7-MeG and N7-EtG respectively. The high sensitivity achieved here makes this method applicable to small experimental animals. This method was applied to measure N7-alkylguanines in liver DNA from mosquito fish (Gambusia affinis) that were exposed to NDMA (N-nitrosodimethylamine) and NDEA (N-nitrosodiethylamine) alone or their combination over a wide range of concentrations (1–100 mg/l). Results showed that the background level of N7-MeG in liver of control fish was 7.89±1.38 μmol/mol of guanine, while N7-EtG was detectable in most of the control fish with a range of 0.05–0.19 μmol/mol of guanine. N7-MeG and N7-EtG were significantly induced by NDMA and NDEA respectively, at a concentration as low as 1 mg/l and increased in a dose-dependent manner. Taken together, this LC-MS/MS assay provides the sensitivity and high throughput required to evaluate the extent of alkylated DNA lesions in small animal models of cancer induced by alkylating agents. PMID:17134374

  3. Multiphysics Application Coupling Toolkit

    SciTech Connect

    Campbell, Michael T.

    2013-12-02

    This particular consortium implementation of the software integration infrastructure will, in large part, refactor portions of the Rocstar multiphysics infrastructure. Development of this infrastructure originated at the University of Illinois DOE ASCI Center for Simulation of Advanced Rockets (CSAR) to support the center's massively parallel multiphysics simulation application, Rocstar, and has continued at IllinoisRocstar, a small company formed near the end of the University-based program. IllinoisRocstar is now licensing these new developments as free, open source, in hopes to help improve their own and others' access to infrastructure which can be readily utilized in developing coupled or composite software systems; with particular attention to more rapid production and utilization of multiphysics applications in the HPC environment. There are two major pieces to the consortium implementation, the Application Component Toolkit (ACT), and the Multiphysics Application Coupling Toolkit (MPACT). The current development focus is the ACT, which is (will be) the substrate for MPACT. The ACT itself is built up from the components described in the technical approach. In particular, the ACT has the following major components: 1.The Component Object Manager (COM): The COM package provides encapsulation of user applications, and their data. COM also provides the inter-component function call mechanism. 2.The System Integration Manager (SIM): The SIM package provides constructs and mechanisms for orchestrating composite systems of multiply integrated pieces.

  4. Multiphysics Application Coupling Toolkit

    Energy Science and Technology Software Center (ESTSC)

    2013-12-02

    This particular consortium implementation of the software integration infrastructure will, in large part, refactor portions of the Rocstar multiphysics infrastructure. Development of this infrastructure originated at the University of Illinois DOE ASCI Center for Simulation of Advanced Rockets (CSAR) to support the center's massively parallel multiphysics simulation application, Rocstar, and has continued at IllinoisRocstar, a small company formed near the end of the University-based program. IllinoisRocstar is now licensing these new developments as free, openmore » source, in hopes to help improve their own and others' access to infrastructure which can be readily utilized in developing coupled or composite software systems; with particular attention to more rapid production and utilization of multiphysics applications in the HPC environment. There are two major pieces to the consortium implementation, the Application Component Toolkit (ACT), and the Multiphysics Application Coupling Toolkit (MPACT). The current development focus is the ACT, which is (will be) the substrate for MPACT. The ACT itself is built up from the components described in the technical approach. In particular, the ACT has the following major components: 1.The Component Object Manager (COM): The COM package provides encapsulation of user applications, and their data. COM also provides the inter-component function call mechanism. 2.The System Integration Manager (SIM): The SIM package provides constructs and mechanisms for orchestrating composite systems of multiply integrated pieces.« less

  5. 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.

  6. Heterogeneous, weakly coupled map lattices

    NASA Astrophysics Data System (ADS)

    Sotelo Herrera, M.a. Dolores; San Martín, Jesús; Porter, Mason A.

    2016-07-01

    Coupled map lattices (CMLs) are often used to study emergent phenomena in nature. It is typically assumed (unrealistically) that each component is described by the same map, and it is important to relax this assumption. In this paper, we characterize periodic orbits and the laminar regime of type-I intermittency in heterogeneous weakly coupled map lattices (HWCMLs). We show that the period of a cycle in an HWCML is preserved for arbitrarily small coupling strengths even when an associated uncoupled oscillator would experience a period-doubling cascade. Our results characterize periodic orbits both near and far from saddle-node bifurcations, and we thereby provide a key step for examining the bifurcation structure of heterogeneous CMLs.

  7. 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.

  8. Small satellites

    NASA Technical Reports Server (NTRS)

    Thomas, P.; Veverka, J.; Dermott, S.

    1986-01-01

    Satellites smaller than Mimas (r = 195 km) are distinguished by irregular overall shapes and by rough limb topography. Material properties and impact cratering dominate the shaping of these objects. Long fragmentation histories can produce a variety of internal structures, but so far there is no direct evidence that any small satellite is an equilibrium ellipsoid made up of noncohesive gravitationally bound rubble. One many bodies that orbit close to their primary the tidal and rotational components of surface gravity strongly affect the directions of local g and thereby affect the redistribution of regolith by mass wasting. Downslope movement of regolith is extensive on Deimos, and is probably effective on many other small satellites. It is shown that in some cases observed patterns of downslope mass wasting cold produce useful constraints on the satellite's mean density. The diversity of features seen in the few high-resolution images of small satellites currently available suggests that these objects have undergone complex histories of cratering, fragmentation, and regolith evolution.

  9. 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

  10. 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

  11. Small-world networks

    NASA Astrophysics Data System (ADS)

    Strogatz, Steven

    Everyone is familiar with the small-world phenomenon: soon after meeting a stranger, we are often suprised to discover that we have a mutual friend, or that we are somehow linked by a short chain of friends. In this talk, I'll present evidence that the small-world phenomenon is more than a curiosity of social networks — it is actually a general property of large, sparse networks whose topology is neither completely regular nor completely random. To check this idea, Duncan Watts and I have analyzed three networks of scientific interest: the neural network of the nematode worm C. elegans, the electrical power grid of the western United States, and the collaboration graph of actors in feature films. All three are small worlds, in the sense that the average number of "handshakes" separating any two members is extremely small (close to the theoretical lower limit set by a random graph). Yet at the same time, all three networks exhibit much more local clustering than a random net, demonstrating that they are not random. I'll also discuss a class of model networks that interpolate between regular lattices and random graphs. Previous theoretical research on complex systems in a wide range of disciplines has focused almost exclusively on networks that are either regular or random. Real networks often lie somewhere in between. Our mathematical model shows that networks in this middle ground tend to exhibit the small-world phenomenon, thanks to the presence of a few long-range edges that link parts of the graph that would otherwise be far apart. Furthermore, we find that when various dynamical systems are coupled in a small-world fashion, they exhibit much greater propagation speed, computational power, and synchronizability than their locally connected, regular counterparts. We explore the implications of these results for simple models of disease spreading, global computation in cellular automata, and collective locking of biological oscillators.

  12. Elemental analysis of soils using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and laser-induced breakdown spectroscopy (LIBS) with multivariate discrimination: tape mounting as an alternative to pellets for small forensic transfer specimens.

    PubMed

    Jantzi, Sarah C; Almirall, José R

    2014-01-01

    Elemental analysis of soil is a useful application of both laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and laser-induced breakdown spectroscopy (LIBS) in geological, agricultural, environmental, archeological, planetary, and forensic sciences. In forensic science, the question to be answered is often whether soil specimens found on objects (e.g., shoes, tires, or tools) originated from the crime scene or other location of interest. Elemental analysis of the soil from the object and the locations of interest results in a characteristic elemental profile of each specimen, consisting of the amount of each element present. Because multiple elements are measured, multivariate statistics can be used to compare the elemental profiles in order to determine whether the specimen from the object is similar to one of the locations of interest. Previous work involved milling and pressing 0.5 g of soil into pellets before analysis using LA-ICP-MS and LIBS. However, forensic examiners prefer techniques that require smaller samples, are less time consuming, and are less destructive, allowing for future analysis by other techniques. An alternative sample introduction method was developed to meet these needs while still providing quantitative results suitable for multivariate comparisons. The tape-mounting method involved deposition of a thin layer of soil onto double-sided adhesive tape. A comparison of tape-mounting and pellet method performance is reported for both LA-ICP-MS and LIBS. Calibration standards and reference materials, prepared using the tape method, were analyzed by LA-ICP-MS and LIBS. As with the pellet method, linear calibration curves were achieved with the tape method, as well as good precision and low bias. Soil specimens from Miami-Dade County were prepared by both the pellet and tape methods and analyzed by LA-ICP-MS and LIBS. Principal components analysis and linear discriminant analysis were applied to the multivariate data

  13. Positive behavioural support in schools for children and adolescents with intellectual disabilities whose behaviour challenges: An exploration of the economic case.

    PubMed

    Iemmi, Valentina; Knapp, Martin; Brown, Freddy Jackson

    2016-09-01

    Decision-makers with limited budgets want to know the economic consequences of their decisions. Is there an economic case for positive behavioural support (PBS)? A small before-after study assessing the impact of PBS on challenging behaviours and positive social and communication skills in children and adolescents with intellectual disabilities and behaviours that challenge was followed by an evaluation of costs. Results were compared with the costs of alternative packages of care currently available in England obtained from a Delphi exercise conducted alongside the study. Children and adolescents supported with PBS showed improvement in challenging behaviours and social and communication skills, at a total weekly cost of GBP 1909 (and GBP 1951 including carer-related costs). PBS in schools for children and adolescents with intellectual disabilities and behaviours that challenge may help to support them in the community with potential improvements in outcomes and also cost advantages. PMID:26912505

  14. Digital Fluoroscopy with AN Optically Coupled Charge-Coupled Device

    NASA Astrophysics Data System (ADS)

    Liu, Hong

    1992-01-01

    This research was aimed at investigating the potential of developing an optically coupled charge-coupled device (CCD) imaging system for some digital fluoroscopic applications. The viability of this concept for fluoroscopic imaging was studied with respect to image intensifier-television (II -TV) techniques. The anticipated advantages of the optically coupled CCD, compared with II-TV, include higher contrast sensitivity, larger dynamic range, moderate spatial resolution and clinically acceptable dose. Following an investigation of some theoretical and practical issues concerning the optical coupling efficiency between the intensifying screen and the CCD imager, mathematical methods were developed to relate the signal, signal-to -noise ratio, and x-ray quantum efficiency of the optically coupled CCD imaging chain. The spatial resolution of the system was also analyzed. Using an ultra-sensitive CCD, as well as improved scintillating and optical coupling techniques, we built a laboratory system for experiments. We conducted measurements of the modulation transfer function (MTF), contrast sensitivity, contrast-detail detectability and detector contrast. The results suggest that the lesion detectability of our sub-optimal system was comparable to that of a screen-film technique under the same radiation dose, and was significantly better than II-TV fluoroscopy. Potential clinical applications of our system include mammography, pre-operational localization, pediatric chest radiography, and single tracer autoradiography. Images of selected phantoms, pathological specimens and small animals were acquired to demonstrate the radiologic quality attainable for such procedures. We conclude that developing an x-ray quantum limited, pseudo-real time, digital fluoroscopic imaging system (for some applications) without an II appears to be theoretically and technically feasible. The successful development of optically coupled CCD fluoroscopy has the potential for improving the

  15. Digital fluoroscopy with an optically coupled charge-coupled device

    NASA Astrophysics Data System (ADS)

    Liu, Hong

    1992-07-01

    This research was aimed at investigating the potential of developing an optically coupled charge-coupled device (CCD) imaging system for some digital fluoroscopic applications. The viability of this concept for fluoroscopic imaging was studied with respect to image intensifier-television (II-TV) techniques. The anticipated advantages of the optically coupled CCD, compared with II-TV, include higher contrast sensitivity, larger dynamic range, moderate spatial resolution and clinically acceptable dose. Following an investigation of some theoretical and practical issues concerning the optical coupling efficiency between the intensifying screen and the CCD imager, mathematical methods were developed to relate the signal, signal-to-noise ratio, and x-ray quantum efficiency of the optically coupled CCD imaging chain. The spatial resolution of the system was also analyzed. Using an ultra-sensitive CCD, as well as improved scintillating and optical coupling techniques, we built a laboratory system for experiments. We conducted measurements of the modulation transfer function (MTF), contrast sensitivity, contrast-detail detectability and detector contrast. The results suggest that the lesion detectability of our sub-optimal system was comparable to that of a screen-film technique under the same radiation dose, and was significantly better than II-TV fluoroscopy. Potential clinical applications of our system include mammography, pre-operational localization, pediatric chest radiography, and single tracer autoradiography. Images of selected phantoms, pathological specimens and small animals were acquired to demonstrate the radiologic quality attainable for such procedures. We conclude that developing an x-ray quantum limited, pseudo-real time, digital fluoroscopic imaging system (for some applications) without an II appears to be theoretically and technically feasible. The successful development of optically coupled CCD fluoroscopy has the potential for improving the quality

  16. Automated monitoring and quantitative analysis of feeding behaviour in Drosophila

    PubMed Central

    Itskov, Pavel M.; Moreira, José-Maria; Vinnik, Ekaterina; Lopes, Gonçalo; Safarik, Steve; Dickinson, Michael H.; Ribeiro, Carlos

    2014-01-01

    Food ingestion is one of the defining behaviours of all animals, but its quantification and analysis remain challenging. This is especially the case for feeding behaviour in small, genetically tractable animals such as Drosophila melanogaster. Here, we present a method based on capacitive measurements, which allows the detailed, automated and high-throughput quantification of feeding behaviour. Using this method, we were able to measure the volume ingested in single sips of an individual, and monitor the absorption of food with high temporal resolution. We demonstrate that flies ingest food by rhythmically extending their proboscis with a frequency that is not modulated by the internal state of the animal. Instead, hunger and satiety homeostatically modulate the microstructure of feeding. These results highlight similarities of food intake regulation between insects, rodents, and humans, pointing to a common strategy in how the nervous systems of different animals control food intake. PMID:25087594

  17. Singularities of the Partition Function for the Ising Model Coupled to 2D Quantum Gravity

    NASA Astrophysics Data System (ADS)

    Ambjørn, J.; Anagnostopoulos, K. N.; Magnea, U.

    We study the zeros in the complex plane of the partition function for the Ising model coupled to 2D quantum gravity for complex magnetic field and real temperature, and for complex temperature and real magnetic field, respectively. We compute the zeros by using the exact solution coming from a two-matrix model and by Monte-Carlo simulations of Ising spins on dynamical triangulations. We present evidence that the zeros form simple one-dimensional curves in the complex plane, and that the critical behaviour of the system is governed by the scaling of the distribution of the singularities near the critical point. Despite the small size of the systems studied, we can obtain a reasonable estimate of the (known) critical exponents.

  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. A multilevel perspective to explain recycling behaviour in communities.

    PubMed

    Tabernero, Carmen; Hernández, Bernardo; Cuadrado, Esther; Luque, Bárbara; Pereira, Cícero R

    2015-08-15

    Previous research on the motivation for environmentally responsible behaviour has focused mainly on individual variables, rather than organizational or collective variables. Therefore, the results of those studies are hardly applicable to environmental management. This study considers individual, collective, and organizational variables together that contribute to the management of environmental waste. The main aim is to identify, through the development of a multilevel model, those predictive variables of recycling behaviour that help organizations to increase the recycling rates in their communities. Individual (age, gender, educational level, self-efficacy with respect to residential recycling, individual recycling behaviour), organizational (satisfaction with the quality of the service provided by a recycling company), and collective (community recycling rates, number of inhabitants, community efficacy beliefs) motivational factors relevant to recycling behaviour were analysed. A sample of 1501 residents from 55 localities was surveyed. The results of multilevel analyses indicated that there was significant variability within and between localities. Interactions between variables at the level of the individual (e.g. satisfaction with service quality) and variables at the level of the collective (e.g. community efficacy) predicted recycling behaviour in localities with low and high community recycling rates and large and small populations. The interactions showed that the relationship between self-efficacy and recycling is stronger in localities with weak community efficacy beliefs than in communities with strong beliefs. The findings show that the relationship between satisfaction with service quality and recycling behaviour is stronger in localities with strong community efficacy beliefs than in communities with weaker beliefs and a smaller population. The results are discussed accordingly in relation to theory and possible contribution to waste management

  1. Gene variants associated with antisocial behaviour: A latent variable approach

    PubMed Central

    Bentley, Mary Jane; Lin, Haiqun; Fernandez, Thomas V.; Lee, Maria; Yrigollen, Carolyn M.; Pakstis, Andrew J.; Katsovich, Liliya; Olds, David L.; Grigorenko, Elena L.; Leckman, James F.

    2013-01-01

    Objective The aim of this study was to determine if a latent variable approach might be useful in identifying shared variance across genetic risk alleles that is associated with antisocial behaviour at age 15 years. Methods Using a conventional latent variable approach, we derived an antisocial phenotype in 328 adolescents utilizing data from a 15-year follow-up of a randomized trial of a prenatal and infancy nurse-home visitation program in Elmira, New York. We then investigated, via a novel latent variable approach, 450 informative genetic polymorphisms in 71 genes previously associated with antisocial behaviour, drug use, affiliative behaviours, and stress response in 241 consenting individuals for whom DNA was available. Haplotype and Pathway analyses were also performed. Results Eight single-nucleotide polymorphisms (SNPs) from 8 genes contributed to the latent genetic variable that in turn accounted for 16.0% of the variance within the latent antisocial phenotype. The number of risk alleles was linearly related to the latent antisocial variable scores. Haplotypes that included the putative risk alleles for all 8 genes were also associated with higher latent antisocial variable scores. In addition, 33 SNPs from 63 of the remaining genes were also significant when added to the final model. Many of these genes interact on a molecular level, forming molecular networks. The results support a role for genes related to dopamine, norepinephrine, serotonin, glutamate, opioid, and cholinergic signaling as well as stress response pathways in mediating susceptibility to antisocial behaviour. Conclusions This preliminary study supports use of relevant behavioural indicators and latent variable approaches to study the potential “co-action” of gene variants associated with antisocial behaviour. It also underscores the cumulative relevance of common genetic variants for understanding the etiology of complex behaviour. If replicated in future studies, this approach may

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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

  7. The behavioural/dysexecutive variant of Alzheimer's disease: clinical, neuroimaging and pathological features.

    PubMed

    Ossenkoppele, Rik; Pijnenburg, Yolande A L; Perry, David C; Cohn-Sheehy, Brendan I; Scheltens, Nienke M E; Vogel, Jacob W; Kramer, Joel H; van der Vlies, Annelies E; La Joie, Renaud; Rosen, Howard J; van der Flier, Wiesje M; Grinberg, Lea T; Rozemuller, Annemieke J; Huang, Eric J; van Berckel, Bart N M; Miller, Bruce L; Barkhof, Frederik; Jagust, William J; Scheltens, Philip; Seeley, William W; Rabinovici, Gil D

    2015-09-01

    A 'frontal variant of Alzheimer's disease' has been described in patients with predominant behavioural or dysexecutive deficits caused by Alzheimer's disease pathology. The description of this rare Alzheimer's disease phenotype has been limited to case reports and small series, and many clinical, neuroimaging and neuropathological characteristics are not well understood. In this retrospective study, we included 55 patients with Alzheimer's disease with a behavioural-predominant presentation (behavioural Alzheimer's disease) and a neuropathological diagnosis of high-likelihood Alzheimer's disease (n = 17) and/or biomarker evidence of Alzheimer's disease pathology (n = 44). In addition, we included 29 patients with autopsy/biomarker-defined Alzheimer's disease with a dysexecutive-predominant syndrome (dysexecutive Alzheimer's disease). We performed structured chart reviews to ascertain clinical features. First symptoms were more often cognitive (behavioural Alzheimer's disease: 53%; dysexecutive Alzheimer's disease: 83%) than behavioural (behavioural Alzheimer's disease: 25%; dysexecutive Alzheimer's disease: 3%). Apathy was the most common behavioural feature, while hyperorality and perseverative/compulsive behaviours were less prevalent. Fifty-two per cent of patients with behavioural Alzheimer's disease met diagnostic criteria for possible behavioural-variant frontotemporal dementia. Overlap between behavioural and dysexecutive Alzheimer's disease was modest (9/75 patients). Sixty per cent of patients with behavioural Alzheimer's disease and 40% of those with the dysexecutive syndrome carried at least one APOE ε4 allele. We also compared neuropsychological test performance and brain atrophy (applying voxel-based morphometry) with matched autopsy/biomarker-defined typical (amnestic-predominant) Alzheimer's disease (typical Alzheimer's disease, n = 58), autopsy-confirmed/Alzheimer's disease biomarker-negative behavioural variant frontotemporal dementia (n = 59

  8. A dielectric elastomer actuator coupled with water: snap-through instability and giant deformation

    NASA Astrophysics Data System (ADS)

    Godaba, Hareesh; Foo, Choon Chiang; Zhang, Zhi Qian; Khoo, Boo Cheong; Zhu, Jian

    2015-04-01

    A dielectric elastomer actuator is one class of soft actuators which can deform in response to voltage. Dielectric elastomer actuators coupled with liquid have recently been developed as soft pumps, soft lenses, Braille displays, etc. In this paper, we conduct experiments to investigate the performance of a dielectric elastomer actuator which is coupled with water. The membrane is subject to a constant water pressure, which is found to significantly affect the electromechanical behaviour of the membrane. When the pressure is small, the membrane suffers electrical breakdown before snap-through instability, and achieves a small voltage-induced deformation. When the pressure is higher to make the membrane near the verge of the instability, the membrane can achieve a giant voltage-induced deformation, with an area strain of 1165%. When the pressure is large, the membrane suffers pressure-induced snap-through instability and may collapse due to a large amount of liquid enclosed by the membrane. Theoretical analyses are conducted to interpret these experimental observations.

  9. 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

  10. 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.

  11. Herd behaviour experimental testing in laboratory artificial stock market settings. Behavioural foundations of stylised facts of financial returns

    NASA Astrophysics Data System (ADS)

    Manahov, Viktor; Hudson, Robert

    2013-10-01

    Many scholars express concerns that herding behaviour causes excess volatility, destabilises financial markets, and increases the likelihood of systemic risk. We use a special form of the Strongly Typed Genetic Programming (STGP) technique to evolve a stock market divided into two groups-a small subset of artificial agents called ‘Best Agents’ and a main cohort of agents named ‘All Agents’. The ‘Best Agents’ perform best in term of the trailing return of a wealth moving average. We then investigate whether herding behaviour can arise when agents trade Dow Jones, General Electric, and IBM financial instruments in four different artificial stock markets. This paper uses real historical quotes of the three financial instruments to analyse the behavioural foundations of stylised facts such as leptokurtosis, non-IIDness, and volatility clustering. We found evidence of more herding in a group of stocks than in individual stocks, but the magnitude of herding does not contribute to the mispricing of assets in the long run. Our findings suggest that the price formation process caused by the collective behaviour of the entire market exhibit less herding and is more efficient than the segmented market populated by a small subset of agents. Hence, greater genetic diversity leads to greater consistency with fundamental values and market efficiency.

  12. 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

  13. 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

  14. 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

  15. 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

  16. 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…

  17. 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.

  18. The QCD running coupling

    DOE PAGESBeta

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

    2016-05-09

    Here, we review present knowledge onmore » $$\\alpha_{s}$$, the Quantum Chromodynamics (QCD) running coupling. The dependence of $$\\alpha_s(Q^2)$$ on momentum transfer $Q$ encodes the underlying dynamics of hadron physics --from color confinement in the infrared domain to asymptotic freedom at short distances. We will survey our present theoretical and empirical knowledge of $$\\alpha_s(Q^2)$$, including constraints at high $Q^2$ predicted by perturbative QCD, and constraints at small $Q^2$ based on models of nonperturbative dynamics. In the first, introductory, part of this review, we explain the phenomenological meaning of the coupling, the reason for its running, and the challenges facing a complete understanding of its analytic behavior in the infrared domain. In the second, more technical, part of the review, we discuss $$\\alpha_s(Q^2)$$ in the high momentum transfer domain of QCD. We review how $$\\alpha_s$$ is defined, including its renormalization scheme dependence, the definition of its renormalization scale, the utility of effective charges, as well as `` Commensurate Scale Relations" which connect the various definitions of the QCD coupling without renormalization scale ambiguity. We also report recent important experimental measurements and advanced theoretical analyses which have led to precise QCD predictions at high energy. As an example of an important optimization procedure, we discuss the ``Principle of Maximum Conformality" which enhances QCD's predictive power by removing the dependence of the predictions for physical observables on the choice of the gauge and renormalization scheme. In last part of the review, we discuss $$\\alpha_s(Q^2)$$ in the low momentum transfer domain, where there has been no consensus on how to define $$\\alpha_s(Q^2)$$ or its analytic behavior. We will discuss the various approaches used for low energy calculations. Among them, we will discuss the light-front holographic approach to QCD in the strongly coupled

  19. Exploring Group Forming Strategies by Examining Participation Behaviours during Whole Class Discussions

    ERIC Educational Resources Information Center

    Jahng, Namsook; Bullen, Mark

    2012-01-01

    The purpose of this study was to explore group forming strategies by examining participation behaviours during whole class discussions associated with active participation in a following small group activity. Written communication data, posted in class discussion forums (843 messages/70,432 words) and small group forums (732 messages/59,394…

  20. Chimera states in coupled Kuramoto oscillators with inertia.

    PubMed

    Olmi, Simona

    2015-12-01

    The dynamics of two symmetrically coupled populations of rotators is studied for different values of the inertia. The system is characterized by different types of solutions, which all coexist with the fully synchronized state. At small inertia, the system is no more chaotic and one observes mainly quasi-periodic chimeras, while the usual (stationary) chimera state is not anymore observable. At large inertia, one observes two different kind of chaotic solutions with broken symmetry: the intermittent chaotic chimera, characterized by a synchronized population and a population displaying a turbulent behaviour, and a second state where the two populations are both chaotic but whose dynamics adhere to two different macroscopic attractors. The intermittent chaotic chimeras are characterized by a finite life-time, whose duration increases as a power-law with the system size and the inertia value. Moreover, the chaotic population exhibits clear intermittent behavior, displaying a laminar phase where the two populations tend to synchronize, and a turbulent phase where the macroscopic motion of one population is definitely erratic. In the thermodynamic limit, these states survive for infinite time and the laminar regimes tends to disappear, thus giving rise to stationary chaotic solutions with broken symmetry contrary to what observed for chaotic chimeras on a ring geometry. PMID:26723164

  1. Chimera states in coupled Kuramoto oscillators with inertia

    NASA Astrophysics Data System (ADS)

    Olmi, Simona

    2015-12-01

    The dynamics of two symmetrically coupled populations of rotators is studied for different values of the inertia. The system is characterized by different types of solutions, which all coexist with the fully synchronized state. At small inertia, the system is no more chaotic and one observes mainly quasi-periodic chimeras, while the usual (stationary) chimera state is not anymore observable. At large inertia, one observes two different kind of chaotic solutions with broken symmetry: the intermittent chaotic chimera, characterized by a synchronized population and a population displaying a turbulent behaviour, and a second state where the two populations are both chaotic but whose dynamics adhere to two different macroscopic attractors. The intermittent chaotic chimeras are characterized by a finite life-time, whose duration increases as a power-law with the system size and the inertia value. Moreover, the chaotic population exhibits clear intermittent behavior, displaying a laminar phase where the two populations tend to synchronize, and a turbulent phase where the macroscopic motion of one population is definitely erratic. In the thermodynamic limit, these states survive for infinite time and the laminar regimes tends to disappear, thus giving rise to stationary chaotic solutions with broken symmetry contrary to what observed for chaotic chimeras on a ring geometry.

  2. Chimera states in coupled Kuramoto oscillators with inertia

    SciTech Connect

    Olmi, Simona

    2015-12-15

    The dynamics of two symmetrically coupled populations of rotators is studied for different values of the inertia. The system is characterized by different types of solutions, which all coexist with the fully synchronized state. At small inertia, the system is no more chaotic and one observes mainly quasi-periodic chimeras, while the usual (stationary) chimera state is not anymore observable. At large inertia, one observes two different kind of chaotic solutions with broken symmetry: the intermittent chaotic chimera, characterized by a synchronized population and a population displaying a turbulent behaviour, and a second state where the two populations are both chaotic but whose dynamics adhere to two different macroscopic attractors. The intermittent chaotic chimeras are characterized by a finite life-time, whose duration increases as a power-law with the system size and the inertia value. Moreover, the chaotic population exhibits clear intermittent behavior, displaying a laminar phase where the two populations tend to synchronize, and a turbulent phase where the macroscopic motion of one population is definitely erratic. In the thermodynamic limit, these states survive for infinite time and the laminar regimes tends to disappear, thus giving rise to stationary chaotic solutions with broken symmetry contrary to what observed for chaotic chimeras on a ring geometry.

  3. Preschool Children with Intellectual Disability: Syndrome Specificity, Behaviour Problems, and Maternal Well-Being

    PubMed Central

    Eisenhower, A. S.; Baker, Bruce L.; Blacher, J.

    2011-01-01

    Background Children with intellectual disability (ID) are at heightened risk for behaviour problems and diagnosed mental disorder. Likewise, mothers of children with ID are more stressed than mothers of typically-developing children. Research on behavioural phenotypes suggests that different syndromes of ID may be associated with distinct child behavioural risks and maternal well-being risks. In the present study, maternal reports of child behaviour problems and maternal well-being were examined for syndrome-specific differences. Methods The present authors studied the early manifestation and continuity of syndrome-specific behaviour problems in 215 preschool children belonging to 5 groups (typically-developing, undifferentiated developmental delays, Down syndrome, autism, cerebral palsy), as well as the relation of syndrome group to maternal well-being. Results At age 3, children with autism and cerebral palsy showed the highest levels of behaviour problems, and children with Down syndrome and typically-developing children showed the lowest levels. Mothers of children with autism reported more parenting stress than all other groups. These syndrome-specific patterns of behaviour and maternal stress were stable across ages 3, 4 and 5 years, except for relative increases in behaviour problems and maternal stress in the Down syndrome and cerebral palsy groups. Child syndrome contributed to maternal stress even after accounting for differences in behaviour problems and cognitive level. Conclusions These results, although based on small syndrome groups, suggest that phenotypic expressions of behaviour problems are manifested as early as age 3. These behavioural differences were paralleled by differences in maternal stress, such that mothers of children with autism are at elevated risk for high stress. In addition, there appear to be other unexamined characteristics of these syndromes, beyond behaviour problems, which also contribute to maternal stress. PMID:16108983

  4. Effects of a Short Teacher Training Programme on the Management of Children's Sexual Behaviours: A Pilot Study

    ERIC Educational Resources Information Center

    Charnaud, Jean-Paul; Turner, William

    2015-01-01

    This small-scale quasi-experimental study set out to examine the effects of a brief training programme aiming to develop primary school teachers' knowledge, attitudes and confidence in recognising and responding to children who display sexual behaviours. Data on prevalence of sexual behaviours observed by teachers in the study, their level of…

  5. Neurovascular coupling: a parallel implementation

    PubMed Central

    Dormanns, Katharina; Brown, Richard G.; David, Tim

    2015-01-01

    A numerical model of neurovascular coupling (NVC) is presented based on neuronal activity coupled to vasodilation/contraction models via the astrocytic mediated perivascular K+ and the smooth muscle cell (SMC) Ca2+ pathway termed a neurovascular unit (NVU). Luminal agonists acting on P2Y receptors on the endothelial cell (EC) surface provide a flux of inositol trisphosphate (IP3) into the endothelial cytosol. This concentration of IP3 is transported via gap junctions between EC and SMC providing a source of sarcoplasmic derived Ca2+ in the SMC. The model is able to relate a neuronal input signal to the corresponding vessel reaction (contraction or dilation). A tissue slice consisting of blocks, each of which contain an NVU is connected to a space filling H-tree, simulating a perfusing arterial tree (vasculature) The model couples the NVUs to the vascular tree via a stretch mediated Ca2+ channel on both the EC and SMC. The SMC is induced to oscillate by increasing an agonist flux in the EC and hence increased IP3 induced Ca2+ from the SMC stores with the resulting calcium-induced calcium release (CICR) oscillation inhibiting NVC thereby relating blood flow to vessel contraction and dilation following neuronal activation. The coupling between the vasculature and the set of NVUs is relatively weak for the case with agonist induced where only the Ca2+ in cells inside the activated area becomes oscillatory however, the radii of vessels both inside and outside the activated area oscillate (albeit small for those outside). In addition the oscillation profile differs between coupled and decoupled states with the time required to refill the cytosol with decreasing Ca2+ and increasing frequency with coupling. The solution algorithm is shown to have excellent weak and strong scaling. Results have been generated for tissue slices containing up to 4096 blocks. PMID:26441619

  6. Neurovascular coupling: a parallel implementation.

    PubMed

    Dormanns, Katharina; Brown, Richard G; David, Tim

    2015-01-01

    A numerical model of neurovascular coupling (NVC) is presented based on neuronal activity coupled to vasodilation/contraction models via the astrocytic mediated perivascular K(+) and the smooth muscle cell (SMC) Ca(2+) pathway termed a neurovascular unit (NVU). Luminal agonists acting on P2Y receptors on the endothelial cell (EC) surface provide a flux of inositol trisphosphate (IP3) into the endothelial cytosol. This concentration of IP3 is transported via gap junctions between EC and SMC providing a source of sarcoplasmic derived Ca(2+) in the SMC. The model is able to relate a neuronal input signal to the corresponding vessel reaction (contraction or dilation). A tissue slice consisting of blocks, each of which contain an NVU is connected to a space filling H-tree, simulating a perfusing arterial tree (vasculature) The model couples the NVUs to the vascular tree via a stretch mediated Ca(2+) channel on both the EC and SMC. The SMC is induced to oscillate by increasing an agonist flux in the EC and hence increased IP3 induced Ca(2+) from the SMC stores with the resulting calcium-induced calcium release (CICR) oscillation inhibiting NVC thereby relating blood flow to vessel contraction and dilation following neuronal activation. The coupling between the vasculature and the set of NVUs is relatively weak for the case with agonist induced where only the Ca(2+) in cells inside the activated area becomes oscillatory however, the radii of vessels both inside and outside the activated area oscillate (albeit small for those outside). In addition the oscillation profile differs between coupled and decoupled states with the time required to refill the cytosol with decreasing Ca(2+) and increasing frequency with coupling. The solution algorithm is shown to have excellent weak and strong scaling. Results have been generated for tissue slices containing up to 4096 blocks. PMID:26441619

  7. Mapping HIV/STI behavioural surveillance in Europe

    PubMed Central

    2010-01-01

    Background Used in conjunction with biological surveillance, behavioural surveillance provides data allowing for a more precise definition of HIV/STI prevention strategies. In 2008, mapping of behavioural surveillance in EU/EFTA countries was performed on behalf of the European Centre for Disease prevention and Control. Method Nine questionnaires were sent to all 31 member States and EEE/EFTA countries requesting data on the overall behavioural and second generation surveillance system and on surveillance in the general population, youth, men having sex with men (MSM), injecting drug users (IDU), sex workers (SW), migrants, people living with HIV/AIDS (PLWHA), and sexually transmitted infection (STI) clinics patients. Requested data included information on system organisation (e.g. sustainability, funding, institutionalisation), topics covered in surveys and main indicators. Results Twenty-eight of the 31 countries contacted supplied data. Sixteen countries reported an established behavioural surveillance system, and 13 a second generation surveillance system (combination of biological surveillance of HIV/AIDS and STI with behavioural surveillance). There were wide differences as regards the year of survey initiation, number of populations surveyed, data collection methods used, organisation of surveillance and coordination with biological surveillance. The populations most regularly surveyed are the general population, youth, MSM and IDU. SW, patients of STI clinics and PLWHA are surveyed less regularly and in only a small number of countries, and few countries have undertaken behavioural surveys among migrant or ethnic minorities populations. In many cases, the identification of populations with risk behaviour and the selection of populations to be included in a BS system have not been formally conducted, or are incomplete. Topics most frequently covered are similar across countries, although many different indicators are used. In most countries, sustainability

  8. Tweezers for Chimeras in Small Networks

    NASA Astrophysics Data System (ADS)

    Omelchenko, Iryna; Omel'chenko, Oleh E.; Zakharova, Anna; Wolfrum, Matthias; Schöll, Eckehard

    2016-03-01

    We propose a control scheme which can stabilize and fix the position of chimera states in small networks. Chimeras consist of coexisting domains of spatially coherent and incoherent dynamics in systems of nonlocally coupled identical oscillators. Chimera states are generally difficult to observe in small networks due to their short lifetime and erratic drifting of the spatial position of the incoherent domain. The control scheme, like a tweezer, might be useful in experiments, where usually only small networks can be realized.

  9. Rupture and creep behaviours of subduction interface controlled by fault zone heterogeneity

    NASA Astrophysics Data System (ADS)

    Wang, Kelin; Brown, Lonn; Gao, Xiang; Bilek, Susan

    2015-04-01

    The behaviour of fault slip varies tremendously, ranging from seismic rupture to aseismic creep. We explore the role of fault zone heterogeneity in controlling large-scale (> 100 km in strike dimension) rupture and creep behaviours of subduction faults. Geometrically smooth subduction faults can (although not always) provide relatively homogeneous structural and stress conditions to allow large fault patches to be locked over prolonged periods and then rupture in great earthquakes. During the rupture, however, frictional heterogeneities arising from lithological changes, pore-fluid pressure variations, and low-amplitude geometrical irregularities always cause a very heterogeneous distribution of stress drop. Although some parts of the fault may undergo high or complete stress drop (local weakening), many other parts undergo very low stress drop or stress increase (local strengthening). The mixing of stress drop and increase in different parts of the rupture zone makes the average stress drop in each great earthquake very small, of the order of a couple of MPa, as widely observed in seismological studies. We use the 2011 Mw=9 Tohoku-oki earthquake to demonstrate this averaging effect. Geometrically extremely rough subduction faults, such as those featuring multiple subducting seamounts, provide very heterogeneous structural and stress conditions that promote creep and numerous small earthquakes. A global inspection of geodetically constrained locking and creeping states of subduction zones indicates that these extremely rough faults all tend to creep (Wang and Bilek, 2014). Depending on the degree of roughness and other geological conditions (e.g., sediment and fluid), some of the rough faults may host a mixture of seismic and aseismic patches and may exhibit a variety of creep behaviour ranging from steady creep to transient creep pulses (i.e., slow slip events) of different time scales. It can be envisioned that the heterogeneity in these rough faults is generally

  10. 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.

  11. 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…

  12. 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.

  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. 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

  16. Micro-fluid exchange coupling apparatus

    NASA Technical Reports Server (NTRS)

    Johnson, J. E., Jr.; Swartz, P. F. (Inventor)

    1980-01-01

    In a macro-fluid exchange, a hollow needle, such as a syringe needle, is provided for penetrating the fluid conduit of the animal. The syringe needle is coupled to a plenum chamber having an inlet and outlet port. The plenum chamber is coupled to the syringe needle via the intermediary of a standard quick disconnect coupling fitting. The plenum chamber is carried at the end of a drive rod which is coupled to a micrometer drive head. The micrometer drive head is slidably and pivotably coupled to a pedestal for adjusting the height and angle of inclination of the needle relative to a reference base support. The needle is positioned adjacent to the incised trachea or a blood vessel of a small animal and the micrometer drive head is operated for penetrating the fluid conduit of the animal.

  17. Relaxation properties of weakly coupled classical systems

    SciTech Connect

    Romero-Rochin, V.; Oppenheim, I.

    1988-10-01

    The relaxation properties of a small classical system weakly coupled to a large classical system which acts as a heat bath are described using a generalized Fokker-Planck equation. The Fokker-Planck equation is derived in general using a modification of the elimination of fast variables techniques previously described. The specific example in which the small system is a harmonic oscillator linearly coupled to the heat bath is treated in detail and it is demonstrated that there is a dynamic frequency shift as well as a statistical shift of the oscillator frequency.

  18. 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)

  19. The role of vegetation on freshwater lens sustainability in small coral islands facing climate change

    NASA Astrophysics Data System (ADS)

    Comte, Jean-Christophe; Join, Jean-Lambert; Banton, Olivier; Nicolini, Eric

    2015-04-01

    Small islands are commonly densely vegetated despite a near absence of surface water and a limited fresh groundwater resource (freshwater lenses) subjected to widespread seawater intrusion. Due to both the shallow depth of the water table, and the low water storage capacity of the soils, vegetation roots abstract water directly from groundwater. Where groundwater contains dissolved salt, roots selectively uptake freshwater which results in salt concentration in groundwater. Groundwater dynamics and salt transport are therefore coupled with vegetation activity and dynamics. However, roots cannot tolerate high levels of dissolved salt due to its phytotoxicity. This results in a buffer mechanism where vegetation regresses, and therefore groundwater uptake decreases, with increased salinization. A numerical groundwater model is applied to a monitored small coral island in the western Indian Ocean to simulate the freshwater lens behaviour and its response to climate changes. A phytotoxicity model is coupled with the groundwater model. Simulations assessed against field observations show the major control currently exerted by the vegetation with regards to the freshwater lens morphology. In particular, thinnest lenses and seawater intrusions observed in the island depressions can be explained by high vegetation activity due to the shallowest water table. Simulation of the response to predicted long-term changes in both groundwater recharge and sea level shows general lens regression by salinization associated with a simultaneous decrease in vegetation activity. Interestingly, the salinization is far less important than when omitting phytotoxicity processes. This demonstrates the need to couple groundwater and ecohydrological models when modelling the impact of climate changes on groundwater resources in small islands.

  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. Young park users' attitudes and behaviour to sun protection.

    PubMed

    Hedges, Trudy; Scriven, Angela

    2010-12-01

    The increase in skin cancer prevalence globally has prompted a range of health promotion sun safety initiatives. An area where evidence has been lacking is on the long-term impact of some of these initiatives on the attitudes and sun protection behaviour of young adults and of the sun protection measures used by people using city parks. This article disseminates a study that examined the knowledge, attitude and behaviour of 18- to 28-year-old Caucasian park users. An interview questionnaire was used with behaviour validation incorporated to corroborate the results and reduce recall bias. A cross comparison of answers and placement into pre-coded responses were made at regular intervals to ensure consistency of data collection. Knowledge of risks associated with sun exposure and knowledge of sun protection methods was high. The most common sources of knowledge on skin cancer prevention were parents and family, followed by television, then magazines and newspapers. Surprisingly, the citing of school sun safety health promotion initiatives as a source of knowledge was low. The vast majority of females and males felt that a suntan had aesthetic qualities and made them look more attractive and healthy. Only a small number of the participants' sun protection behaviour in the park corresponded with their reported normal sun protection behaviour. Males in this study use sunscreen less than females. Females also used sunscreen with a higher sun protection factor. Seeking a tan is intentional behaviour undertaken by the majority of the participants, although females were more likely to seek a tan in comparison to males. The majority of participants had experienced sunburn in the summer period with some reporting severe sunburn. Recommendations are made for a gender specific health promotion approach, which targets familial education with a supportive environment in the school or public domain. PMID:21510096

  2. A closed loop experiment of collective bounce aeroelastic Rotorcraft-Pilot Coupling

    NASA Astrophysics Data System (ADS)

    Masarati, Pierangelo; Quaranta, Giuseppe; Lu, Linghai; Jump, Michael

    2014-01-01

    This work presents an experimental study that investigated the possibility of destabilising a rotorcraft by coupling the biomechanical behaviour of human subjects with the dynamics of the vehicle. The results of a study focused on the behaviour of pilots holding the collective control inceptor in a flight simulator are discussed. The motion of the flight simulation model was restricted to the heave axis, and augmented to include an elastic mode of vibration in addition to the rigid heave degree of freedom. Four different pilots flew several alternative model configurations with different elastic mode frequency and different collective pitch gearing ratios. This resulted in several observable unstable pilot-vehicle interactions at frequencies that cannot be traced back to the rotorcraft dynamics. Unstable oscillatory events evolving into limit cycle oscillations occurred most often at frequencies related to the biomechanics of the flight simulator occupant. They appeared to be task dependent and, in some cases, the trigger could be attributed to specific events. Additionally, it was found that the presence of collective friction alleviates but does not completely eliminate the unstable interactions between the pilot and the rotorcraft. Although not statistically meaningful because of the small set of human subjects available for the study, the results confirmed that the biomechanics transfer function of the pilot is the most influential aspect of the pilot-vehicle system that gives rise to the adverse vertical bounce phenomenon. Additionally, this study gave useful insight into the vehicle parameters that can adversely influence the involuntary interaction of pilots with rotorcraft.

  3. Diagrammatic Vibrational Coupled-Cluster

    NASA Astrophysics Data System (ADS)

    Faucheaux, Jacob A.; Hirata, So

    2015-06-01

    A diagrammatic vibrational coupled-cluster method for calculation of zero-point energies and an equation-of-motion coupled-cluster method for calculation of anharmonic vibrational frequencies are developed. The methods, which we refer to as XVCC and EOM-XVCC respectively, rely on the size-extensive vibrational self-consistient field (XVSCF) method for reference wave functions. The methods retain the efficiency advantages of XVSCF making them suitable for applications to large molecules and solids, while they are numerically shown to accurately predict zero-point energies and frequencies of small molecules as well. In particular, EOM-XVCC is shown to perform well for modes which undergo Fermi resonance where traditional perturbative methods fail. Rules for the systematic generation and interpretation of the XVCC and EOM-XVCC diagrams to any order are presented.

  4. 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.

  5. 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…

  6. 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.

  7. 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

  8. Mobile phone SMS messages can enhance healthy behaviour: a meta-analysis of randomised controlled trials.

    PubMed

    Orr, Jayne A; King, Robert J

    2015-01-01

    Healthy behaviour, such as smoking cessation and adherence to prescribed medications, mitigates illness risk factors but health behaviour change can be challenging. Mobile phone short-message service (SMS) messages are increasingly used to deliver interventions designed to enhance healthy behaviour. This meta-analysis used a random-effects model to synthesise 38 randomised controlled trials that investigated the efficacy of SMS messages to enhance healthy behaviour. Participants (N = 19,641) lived in developed and developing countries and were diverse with respect to age, ethnicity, socioeconomic background and health behaviours targeted for change. SMS messages had a small, positive, significant effect (g = 0.291) on a broad range of healthy behaviour. This effect was maximised when multiple SMS messages per day were used (g = 0.395) compared to using lower frequencies (daily, multiple per week and once-off) (g = 0.244). The low heterogeneity in this meta-analysis (I (2) = 38.619) supports reporting a summary effect size and implies that the effect of SMS messaging is robust, regardless of population characteristics or healthy behaviour targeted. SMS messaging is a simple, cost-effective intervention that can be automated and can reach any mobile phone owner. While the effect size is small, potential health benefits are well worth achieving. PMID:25739668

  9. Behaviour of fish by-catch in the mouth of a crustacean trawl.

    PubMed

    Queirolo, D; Gaete, E; Montenegro, I; Soriguer, M C; Erzini, K

    2012-06-01

    The behaviour of fish by-catch was recorded and characterized by in situ observations in the mouth of a crustacean trawl using an underwater camera system with artificial light, at depths between 106 and 461 m, along the central coast of Chile. The groups or species studied were rattails (family Macrouridae), Chilean hake Merluccius gayi gayi, sharks (orders Carcharhiniformes and Squaliformes), skates (family Rajidae), flatfishes (genus Hippoglossina) and small benthopelagic and demersal fishes (orders Osmeriformes, Stomiiformes, Gadiformes, Ophidiiformes and Perciformes). The fish behaviour was categorized in terms of (1) position in the water column, (2) initial orientation with respect to the trawl, (3) locomotion and (4) swimming speed with respect to the trawl. Rattails, sharks, skates and flatfishes were passive in response to the trawl and showed similar behavioural patterns, with most fishes observed sitting or touching the bottom with no swimming or other activity. Merluccius gayi gayi was the most active species, displaying a wide combination of behavioural responses when the trawl approached. This species showed several behavioural patterns, mainly characterized by swimming forward at variable speed. A fraction of small bentho-pelagic and demersal fishes also showed an active behaviour but always at lower speed than the trawl. The species-specific differences in behaviour in the mouth of the trawl suggest that improvements at the level of the footrope can be made to reduce by-catch, especially of passive species. PMID:22650431

  10. How Small are Small Stars Really?

    NASA Astrophysics Data System (ADS)

    2002-11-01

    VLT Interferometer Measures the Size of Proxima Centauri and Other Nearby Stars [1] Summary At a distance of only 4.2 light-years, Proxima Centauri is the nearest star to the Sun currently known [2]. It is visible as an 11-magnitude object in the southern constellation of Centaurus and is the faintest member of a triple system, together with Alpha Centauri , the brightest (double) star in this constellation. Proxima Centauri is a very-low-mass star, in fact barely massive enough to burn hydrogen to helium in its interior. It is about seven times smaller than the Sun, and the surface temperature is "only" about 3000 degrees, about half of that of our own star. Consequently, it is also much fainter - the intrinsic brightness is only 1/150th of that of our Sun. Low-mass stars are very interesting objects , also because the physical conditions in their interiors have much in common with those of giant planets, like Jupiter in our solar system. A determination of the sizes of the smallest stars has been impossible until now because of their general faintness and lack of adequate instrumentation. However, astronomers have long been keen to move forward in this direction, since such measurements would provide indirect, crucial information about the behaviour of matter under extreme conditions. When the first observations with the VLT Interferometer (VLTI), combining the light from two of the 8.2-m VLT Unit Telescopes (ANTU and MELIPAL), were made one year ago ( ESO PR 23/01 ), interferometric measurements were also obtained of Proxima Centauri . They formed part of the VLTI commissioning and the data were soon released to the ESO community, cf. the special website. Now, an international team of astronomers from Switzerland, France and ESO/Chile has successfully analysed these observations by means of newly developed, advanced software. For the first time ever, they obtained a highly accurate measurement of the size of such a small star . Three other small stars were also

  11. 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.

  12. A Meta-Analytic Study of Couple Interventions during the Transition to Parenthood

    ERIC Educational Resources Information Center

    Pinquart, Martin; Teubert, Daniela

    2010-01-01

    The present meta-analysis integrates results of 21 controlled couple-focused interventions with expectant and new parents. The interventions had, on average, small effects on couple communication (d = 0.28 standard deviation units) and psychological well-being (d = 0.21), as well as very small effects on couple adjustment (d = 0.09). Stronger…

  13. 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…

  14. Flipping of the coordinated triazine moiety in Cu(I)-L2 and the small electronic factor, κel, for direct outer-sphere cross reactions: syntheses, crystal structures and redox behaviour of copper(II)/(I)-L2 complexes (L = 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine).

    PubMed

    Yamada, Atsutoshi; Mabe, Takuya; Yamane, Ryohei; Noda, Kyoko; Wasada, Yuko; Inamo, Masahiko; Ishihara, Koji; Suzuki, Takayoshi; Takagi, Hideo D

    2015-08-21

    -adiabaticity (electronic) factors, κel, for the direct electron transfer processes between [Cu(pdt)2](+/2+) and non-copper metal (Fe(2+) and Co(3+)) complexes were estimated as ca. 10(-7), indicating that the electronic coupling between the d orbitals of copper and of non-copper metals is very small. PMID:26158539

  15. 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…

  16. 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.…

  17. 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…

  18. 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

  19. 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…

  20. Endless forms: human behavioural diversity and evolved universals

    PubMed Central

    Smith, Eric Alden

    2011-01-01

    Human populations have extraordinary capabilities for generating behavioural diversity without corresponding genetic diversity or change. These capabilities and their consequences can be grouped into three categories: strategic (or cognitive), ecological and cultural-evolutionary. Strategic aspects include: (i) a propensity to employ complex conditional strategies, some certainly genetically evolved but others owing to directed invention or to cultural evolution; (ii) situations in which fitness payoffs (or utilities) are frequency-dependent, so that there is no one best strategy; and (iii) the prevalence of multiple equilibria, with history or minor variations in starting conditions (path dependence) playing a crucial role. Ecological aspects refer to the fact that social behaviour and cultural institutions evolve in diverse niches, producing various adaptive radiations and local adaptations. Although environmental change can drive behavioural change, in humans, it is common for behavioural change (especially technological innovation) to drive environmental change (i.e. niche construction). Evolutionary aspects refer to the fact that human capacities for innovation and cultural transmission lead to diversification and cumulative cultural evolution; critical here is institutional design, in which relatively small shifts in incentive structure can produce very different aggregate outcomes. In effect, institutional design can reshape strategic games, bringing us full circle. PMID:21199837

  1. Social behaviour and collective motion in plant-animal worms.

    PubMed

    Franks, Nigel R; Worley, Alan; Grant, Katherine A J; Gorman, Alice R; Vizard, Victoria; Plackett, Harriet; Doran, Carolina; Gamble, Margaret L; Stumpe, Martin C; Sendova-Franks, Ana B

    2016-02-24

    Social behaviour may enable organisms to occupy ecological niches that would otherwise be unavailable to them. Here, we test this major evolutionary principle by demonstrating self-organizing social behaviour in the plant-animal, Symsagittifera roscoffensis. These marine aceol flat worms rely for all of their nutrition on the algae within their bodies: hence their common name. We show that individual worms interact with one another to coordinate their movements so that even at low densities they begin to swim in small polarized groups and at increasing densities such flotillas turn into circular mills. We use computer simulations to: (i) determine if real worms interact socially by comparing them with virtual worms that do not interact and (ii) show that the social phase transitions of the real worms can occur based only on local interactions between and among them. We hypothesize that such social behaviour helps the worms to form the dense biofilms or mats observed on certain sun-exposed sandy beaches in the upper intertidal of the East Atlantic and to become in effect a super-organismic seaweed in a habitat where macro-algal seaweeds cannot anchor themselves. Symsagittifera roscoffensis, a model organism in many other areas in biology (including stem cell regeneration), also seems to be an ideal model for understanding how individual behaviours can lead, through collective movement, to social assemblages. PMID:26911961

  2. Rumination and behavioural factors in Parkinson's disease depression

    PubMed Central

    Julien, Camille L.; Rimes, Katharine A.; Brown, Richard G.

    2016-01-01

    Objective Parkinson's disease is associated with high rates of depression. There is growing interest in non-pharmacological management including psychological approaches such as Cognitive Behaviour Therapy. To date, little research has investigated whether processes that underpin cognitive models of depression, on which such treatment is based, apply in patients with Parkinson's disease. The study aimed to investigate the contribution of core psychological factors to the presence and degree of depressive symptoms. Methods 104 participants completed questionnaires measuring mood, motor disability and core psychological variables, including maladaptive assumptions, rumination, cognitive-behavioural avoidance, illness representations and cognitive-behavioural responses to symptoms. Results Regression analyses revealed that a small number of psychological factors accounted for the majority of depression variance, over and above that explained by overall disability. Participants reporting high levels of rumination, avoidance and symptom focusing experienced more severe depressive symptoms. In contrast, pervasive negative dysfunctional beliefs did not independently contribute to depression variance. Conclusion Specific cognitive (rumination and symptom focusing) and behavioural (avoidance) processes may be key psychological markers of depression in Parkinson's disease and therefore offer important targets for tailored psychological interventions. PMID:26944399

  3. Sexual risk behaviour and donor deferral in Europe.

    PubMed

    Offergeld, R; Kamp, C; Heiden, M; Norda, R; Behr-Gross, M-E

    2014-11-01

    One of the most controversial policies in blood transfusion worldwide is the permanent deferral from donating blood of men with sexual contacts to other men (MSM). This policy was implemented for safety reasons as sex between men is known to be a high risk factor for acquiring severe infectious diseases transmissible by blood transfusion. Sexual contacts among heterosexual persons may hold similar risks but a clear-cut discrimination between different individual risks is impossible. Nevertheless, the current blood donor deferral periods defined by European Union (EU) legislation depend on a distinction of different grades of risk with respect to sexual behaviour. Under the aegis of the Steering Committee on Blood Transfusion (CD-P-TS) of the Council of Europe (CoE), an international working group evaluated epidemiological and behavioural data, modelling studies on residual risk and spread of infections, and studies on adherence to donor selection criteria. The aim was to distinguish sexual behaviour of different risk categories. It was concluded, that existing data confirm that MSM and commercial sex workers (CSW) are groups at high risk. Any further grading lacks a scientific data base. Modelling studies indicate that adherence to deferral policies is of major relevance suggesting that good donor adherence may outweigh the small negative effects on blood safety postulated for changing from permanent to temporary deferral periods for high risk sexual behaviours. The fact that a considerable percentage of donors are MSM - despite the permanent deferral policy - demonstrates the need to increase donor understanding and adherence. PMID:25040600

  4. [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

  5. Mechanics of the trachea and behaviour of its slowly adapting stretch receptors.

    PubMed Central

    Mortola, J P; Sant'Ambrogio, G

    1979-01-01

    1. The trachea is constructed by a series of U-shaped cartilaginous rings supporting a membranous posterior wall. We have studied separately the pressure-volume relationships of the two components. 2. The motion of the membranous posterior wall contributes most to the tracheal volume change caused by any given transmural pressure change; the cartilaginous rings provide a semi-rigid support to the posterior wall and have a far greater compliance with negative than positive transmural pressure. 3. The response of tracheal stretch receptors to transmural pressure can be explained by the mechanical coupling between cartilages and posterior wall. They respond both to positive and negative transmural pressure, they are active at zero transmural pressure and have a point of least activity with small negative transmural pressures. 4. The stress-strain relationship of the posterior wall has been studied in static and dynamic conditions in control situations and after removal of either the tunica fibrosa or the trachealis muscle. Each of these two components contributes to the stiffness of the posterior wall, with the trachealis muscle providing most of its viscosity. 5. The response of tracheal stretch receptors to transverse traction of the posterior membranous wall has been studied in both static and dynamic conditions before and after removal of the tunica fibrosa. The behaviour of these receptors reflects the visco-elastic properties of the trachealis muscle in which they have been localized. PMID:439039

  6. Scaling Limits and Critical Behaviour of the 4 -Dimensional n -Component |\\varphi |^4 Spin Model

    NASA Astrophysics Data System (ADS)

    Bauerschmidt, Roland; Brydges, David C.; Slade, Gordon

    2014-08-01

    We consider the n -component |\\varphi |^4 spin model on {mathbb {Z}}^4 , for all n ge 1 , with small coupling constant. We prove that the susceptibility has a logarithmic correction to mean field scaling, with exponent n+2/n+8 for the logarithm. We also analyse the asymptotic behaviour of the pressure as the critical point is approached, and prove that the specific heat has fractional logarithmic scaling for n =1,2,3 ; double logarithmic scaling for n=4 ; and is bounded when n>4 . In addition, for the model defined on the 4 -dimensional discrete torus, we prove that the scaling limit as the critical point is approached is a multiple of a Gaussian free field on the continuum torus, whereas, in the subcritical regime, the scaling limit is Gaussian white noise with intensity given by the susceptibility. The proofs are based on a rigorous renormalisation group method in the spirit of Wilson, developed in a companion series of papers to study the 4-dimensional weakly self-avoiding walk, and adapted here to the |\\varphi |^4 model.

  7. Ghrelin and feeding behaviour in preterm infants.

    PubMed

    Savino, Francesco; Lupica, Maria Maddalena; Liguori, Stefania Alfonsina; Fissore, Maria Francesca; Silvestro, Leandra

    2012-03-01

    The importance of early life events in the development of metabolic diseases is well recognized. Early postnatal environment, including nutrition, is key to future health, and this is particularly true for preterm infants. It is important that these infants receive sufficient nutrients to prevent growth restriction and promote neurodevelopment, while minimizing predisposition to metabolic diseases later in life. Feeding habits are the fundamental elements of nutrition and are influenced by many factors, including personal and familial habits, socioeconomic status, and cultural environment. In the last decades, there has been an important scientific interest toward the comprehension of the molecular and neural mechanisms regulating appetite. In these networks, act many peptide hormones produced in brain or gut, among which ghrelin is important because of its action in the short-term regulation of food intake and the long-term regulation of body weight. Ghrelin stimulates appetite and plays a role in regulating feeding behaviour. Ghrelin levels vary from fetal life through to early adulthood, with the highest levels observed in the very early years. Cord ghrelin levels have been evaluated in term and preterm newborns and high ghrelin levels have been observed in small-for-gestational age newborns and in newborns with intrauterine growth restriction. Moreover, ghrelin has been detected in term and preterm human breast milk, suggesting that it may play a role in the development of neuroendocrine pathways regulating appetite and energy homeostasis in early life. However, more research is required to better define ghrelin's role in breast milk and on feeding behaviour. PMID:22285781

  8. 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.

  9. 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

  10. 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.

  11. 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

  12. 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.

  13. 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

  14. 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

  15. [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

  16. 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

  17. 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.

  18. Dual Lattice Boltzmann method for electrokinetic coupling : behavior at high and low salinities in rough channels.

    NASA Astrophysics Data System (ADS)

    Fiorentino, Eve-Agnès; Toussaint, Renaud; Jouniaux, Laurence

    2014-05-01

    We study the coupling between hydraulic and electric flows in a porous medium at small scale using the Lattice Boltzmann method. This method is a computational fluid dynamics technique that is used for advection and diffusion modeling. We implement a coupled Lattice Boltzmann algorithm that solves both the mass transport and the electric field arising from charges displacements. The streaming potential and electroosmosis phenomena occur in a variety of situations and derive from this coupling. We focus on the streaming potential which is described using the ratio between the created potential difference and the applied pressure gradient. The streaming potential is assumed to be a linear function of the fluid conductivity, but experimental results highlight anomalous behaviors at low and high salinity. We try to account for them by setting extreme conditions that are likely to generate non-linearities. Several pore radii are tested so as to determine what is the effect of a radius that is comparable to the Debye length, the screening length of the electric potential, due to the ions in the electrolyte. The volumetric integral of the electrical current is calculated for comparison with the 2D simulations. High values of zeta potential are tested to verify if the discrepancy regarding the theoretical result is concentration-dependent. We try to include a surface conductivity term in the coefficient formulation. Some tests including a rugosity on the channel walls are performed. All of these attempts show a normal behaviour of the streaming potential at high salinity. We observe a decrease of the ratio at low conductivity, showing that this ratio is modified when the pore radius becomes negligible compared with the Debye length, which is physically meaningful in little pores at low concentrations. References : S. Pride. Governing equations for the coupled electromagnetics and acoustics of porous media. Physical Review B, 50 : 15678-15696, 1994. D. A. Wolf

  19. Coupled transport processes in semipermeable media

    SciTech Connect

    Jacobsen, J.S.; Carnahan, C.L.

    1990-03-01

    The thermodynamics of irreversible processes leads to nonlinear governing equations for direct and coupled mass transport processes. Analytical solutions of linearized versions of these equations can be used to verify numerical solutions of the nonlinear equations under conditions such that nonlinear terms are relatively small. This report presents derivations of the analytical solutions for one-dimensional and axisymmetric geometries. 7 refs.

  20. Engaged Couples' Reactions to a Marriage Contract.

    ERIC Educational Resources Information Center

    Fisher, C. Daniel

    This article describes the reactions of a small sample of college students from a Northeastern, private nonsectarian university to a marriage contract that was designed by a couple on this campus. The major reasons for writing the contract included apprehension about the pre-marital socialization system in our society, concerns regarding marital…

  1. Capacitance-coupled wiper increases potentiometer life

    NASA Technical Reports Server (NTRS)

    Dimeff, J.

    1968-01-01

    Capacitively-coupled wiper reduces the friction between the sliding contact and the potentiometer element in conventional potentiometers. A small preamplifier employed close to the wiper reduces errors caused by output cable capacitance. The device is friction free with resultant low wear and has high speed and high resolution.

  2. 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

  3. 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

  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. Phase dynamics of coupled oscillators reconstructed from data

    NASA Astrophysics Data System (ADS)

    Rosenblum, Michael; Kralemann, Bjoern; Pikovsky, Arkady

    2013-03-01

    We present a technique for invariant reconstruction of the phase dynamics equations for coupled oscillators from data. The invariant description is achieved by means of a transformation of phase estimates (protophases) obtained from general scalar observables to genuine phases. Staring from the bivariate data, we obtain the coupling functions in terms of these phases. We discuss the importance of the protophase-to-phase transformation for characterization of strength and directionality of interaction. To illustrate the technique we analyse the cardio-respiratory interaction on healthy humans. Our invariant approach is confirmed by high similarity of the coupling functions obtained from different observables of the cardiac system. Next, we generalize the technique to cover the case of small networks of coupled periodic units. We use the partial norms of the reconstructed coupling functions to quantify directed coupling between the oscillators. We illustrate the method by different network motifs for three coupled oscillators. We also discuss nonlinear effects in coupling.

  6. Predictors of physical activity, healthy eating and being smoke-free in teens: a theory of planned behaviour approach.

    PubMed

    Murnaghan, Donna A; Blanchard, Chris M; Rodgers, Wendy M; LaRosa, Jennifer N; MacQuarrie, Colleen R; MacLellan, Debbie L; Gray, Bob J

    2010-10-01

    This paper elicited context specific underlying beliefs for physical activity, fruit and vegetable consumption and smoke-free behaviour from the Theory of Planned Behaviour (TPB), and then determined whether the TPB explained significant variation in intentions and behaviour over a 1 month period in a sample of grade 7-9 (age 12-16 years) adolescents. Eighteen individual interviews and one focus group were used to elicit student beliefs. Analyses of this data produced behavioural, normative and control beliefs which were put into a TPB questionnaire completed by 183 students at time 1 and time 2. The Path analyses from the main study showed that the attitude/intention relationship was moderately large for fruit and vegetable consumption and small to moderate for being smoke free. Perceived behavioural control had a large effect on being smoke free and a moderately large effect for fruit and vegetable consumption and physical activity. Intention had a large direct effect on all three behaviours. Common (e.g. feel better, more energy) and behaviour-specific (e.g., prevent yellow fingers, control my weight) beliefs emerged across the three health behaviours. These novel findings, to the adolescent population, support the importance of specific attention being given to each of the behaviours in future multi-behavioural interventions. PMID:20204952

  7. 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.

  8. 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.

  9. Conformal inflation coupled to matter

    SciTech Connect

    Brax, Philippe

    2014-05-01

    We formulate new conformal models of inflation and dark energy which generalise the Higgs-Dilaton scenario. We embed these models in unimodular gravity whose effect is to break scale invariance in the late time Universe. In the early Universe, inflation occurs close to a maximum of both the scalar potential and the scalar coupling to the Ricci scalar in the Jordan frame. At late times, the dilaton, which decouples from the dynamics during inflation, receives a potential term from unimodular gravity and leads to the acceleration of the Universe. We address two central issues in this scenario. First we show that the Damour-Polyalov mechanism, when non-relativistic matter is present prior to the start of inflation, sets the initial conditions for inflation at the maximum of the scalar potential. We then show that conformal invariance implies that matter particles are not coupled to the dilaton in the late Universe at the classical level. When fermions acquire masses at low energy, scale invariance is broken and quantum corrections induce a coupling between the dilaton and matter which is still small enough to evade the gravitational constraints in the solar system.

  10. Conduction-coupled Tesla transformer

    NASA Astrophysics Data System (ADS)

    Reed, J. L.

    2015-03-01

    A proof-of-principle Tesla transformer circuit is introduced. The new transformer exhibits the high voltage-high power output signal of shock-excited transformers. The circuit, with specification of proper circuit element values, is capable of obtaining extreme oscillatory voltages. The primary and secondary portions of the circuit communicate solely by conduction. The destructive arcing between the primary and secondary inductors in electromagnetically coupled transformers is ubiquitous. Flashover is eliminated in the new transformer as the high-voltage inductors do not interpenetrate and so do not possess an annular volume of electric field. The inductors are remote from one another. The high voltage secondary inductor is isolated in space, except for a base feed conductor, and obtains earth by its self-capacitance to the surroundings. Governing equations, for the ideal case of no damping, are developed from first principles. Experimental, theoretical, and circuit simulator data are presented for the new transformer. Commercial high-temperature superconductors are discussed as a means to eliminate the counter-intuitive damping due to small primary inductances in both the electromagnetic-coupled and new conduction-coupled transformers.

  11. Conduction-coupled Tesla transformer.

    PubMed

    Reed, J L

    2015-03-01

    A proof-of-principle Tesla transformer circuit is introduced. The new transformer exhibits the high voltage-high power output signal of shock-excited transformers. The circuit, with specification of proper circuit element values, is capable of obtaining extreme oscillatory voltages. The primary and secondary portions of the circuit communicate solely by conduction. The destructive arcing between the primary and secondary inductors in electromagnetically coupled transformers is ubiquitous. Flashover is eliminated in the new transformer as the high-voltage inductors do not interpenetrate and so do not possess an annular volume of electric field. The inductors are remote from one another. The high voltage secondary inductor is isolated in space, except for a base feed conductor, and obtains earth by its self-capacitance to the surroundings. Governing equations, for the ideal case of no damping, are developed from first principles. Experimental, theoretical, and circuit simulator data are presented for the new transformer. Commercial high-temperature superconductors are discussed as a means to eliminate the counter-intuitive damping due to small primary inductances in both the electromagnetic-coupled and new conduction-coupled transformers. PMID:25832281

  12. Light, heat, action: neural control of fruit fly behaviour

    PubMed Central

    Owald, David; Lin, Suewei; Waddell, Scott

    2015-01-01

    The fruit fly Drosophila melanogaster has emerged as a popular model to investigate fundamental principles of neural circuit operation. The sophisticated genetics and small brain permit a cellular resolution understanding of innate and learned behavioural processes. Relatively recent genetic and technical advances provide the means to specifically and reproducibly manipulate the function of many fly neurons with temporal resolution. The same cellular precision can also be exploited to express genetically encoded reporters of neural activity and cell-signalling pathways. Combining these approaches in living behaving animals has great potential to generate a holistic view of behavioural control that transcends the usual molecular, cellular and systems boundaries. In this review, we discuss these approaches with particular emphasis on the pioneering studies and those involving learning and memory. PMID:26240426

  13. Integral dependent spin couplings in CI calculations

    NASA Astrophysics Data System (ADS)

    Iberle, K.; Davidson, E. R.

    1982-06-01

    Although the number of ways to combine Slater determinants to form spin eigenfunctions increases rapidly with the number of open shells, most of these spin couplings will make only a small contribution to a given state, provided the spin coupling is chosen judiciously. The technique of limiting calculations to the interacting subspace pioneered by Bunge (1970) was employed by Munch and Davidson (1975) to the vanadium atom. The use of an interacting space looses its advantage in more complex cases. However, the problem can always be reduced to only one interacting spin coupling by making the coefficients integral dependent. The present investigation is concerned with the performance of integral dependent interacting couplings, taking into account the results of three test calculations.

  14. Integral dependent spin couplings in CI calculations

    NASA Technical Reports Server (NTRS)

    Iberle, K.; Davidson, E. R.

    1982-01-01

    Although the number of ways to combine Slater determinants to form spin eigenfunctions increases rapidly with the number of open shells, most of these spin couplings will make only a small contribution to a given state, provided the spin coupling is chosen judiciously. The technique of limiting calculations to the interacting subspace pioneered by Bunge (1970) was employed by Munch and Davidson (1975) to the vanadium atom. The use of an interacting space looses its advantage in more complex cases. However, the problem can always be reduced to only one interacting spin coupling by making the coefficients integral dependent. The present investigation is concerned with the performance of integral dependent interacting couplings, taking into account the results of three test calculations.

  15. Coupled modelling of the effect of overpressure on water discharge in a tile drainage system

    NASA Astrophysics Data System (ADS)

    Henine, H.; Nédélec, Y.; Ribstein, P.

    2014-04-01

    The effect of subsurface drainage on agricultural catchment outflow has been debated for quite some time. Concerning downstream peak flow, it is a complex task to predict the impact of agricultural drainage because different flow media are involved: the soil, pipe drainage networks and open channel networks. In France, drain pipes are designed to operate under a free-surface flow condition. Nevertheless, during intense rainfall events, some pipe sections may flow under pressurised conditions, so that a complex interaction between pipe networks and groundwater flows appears in the vicinity of these sections. In this paper, an integrated modelling strategy is considered in order to analyse these flow interactions. A 1D Saint-Venant network model is combined with a 2D Boussinesq shallow groundwater flow model by means of special internal boundary conditions which take into account the flow interactions. This study follows field experiments conducted in a small subsurface drained catchment, where drainage discharge and pressure heads were monitored in a buried pipe collector and water table profiles were monitored in the field. The simulation results of the coupled model are in good agreement with experimental observations. Moreover, it satisfactorily simulates the behaviour of the drainage system during the pressurisation stages. The model is also applied to a scenario addressing the effect of pressurisation, as compared to non-pressurisation, at the outlet. The coupled model reveals the relation existing between pipe pressurisation and hydrograph timing. Pipe pressurisation results in temporary storage of discharging water, which is released later when pressurisation stops.

  16. Eikonal Scattering at Strong Coupling

    NASA Astrophysics Data System (ADS)

    Irizarry-Gelpi, Melvin Eloy

    The scattering of subatomic particles is a source of important physical phenomena. Decades of work have yielded many techniques for the computation of scattering amplitudes. Most of these techniques involve perturbative quantum field theory and thus apply only at weak coupling. Complementary to scattering is the formation of bound states, which are intrinsically nonperturbative. Regge theory arose in the late 1950s as an attempt to describe, with a single framework, both scattering and the formation of bound states. In Regge theory one obtains an amplitude with bound state poles after analytic continuation of a nonperturbative scattering amplitude, corresponding to a sum of an infinite number of Feynman diagrams at large energy and fixed momentum transfer (but with crossed kinematics). Thus, in order to obtain bound states at fixed energy, one computes an amplitude at large momentum transfer. In this dissertation we calculate amplitudes with bound states in the regime of fixed energy and small momentum transfer. We formulate the elastic scattering problem in terms of many-body path integrals, familiar from quantum mechanics. Then we invoke the semiclassical JWKB approximation, where the path integral is dominated by classical paths. The dynamics in the semiclassical regime are strongly coupled, as found by Halpern and Siegel. When the momentum transfer is small, the classical paths are simple straight lines and the resulting semiclassical amplitudes display a spectrum of bound states that agrees with the spectrum found by solving wave equations with potentials. In this work we study the bound states of matter particles with various types of interactions, including electromagnetic and gravitational interactions. Our work has many analogies with the work started by Alday and Maldacena, who computed scattering amplitudes of gluons at strong coupling with semiclassical quantum mechanics of strings in anti de-Sitter spacetime. We hope that in the future we can apply our

  17. Miniature wireless recording and stimulation system for rodent behavioural testing

    NASA Astrophysics Data System (ADS)

    Pinnell, R. C.; Dempster, J.; Pratt, J.

    2015-12-01

    Objective. Elucidation of neural activity underpinning rodent behaviour has traditionally been hampered by the use of tethered systems and human involvement. Furthermore the combination of deep-brain stimulation (DBS) and various neural recording modalities can lead to complex and time-consuming laboratory setups. For studies of this type, novel tools are required to drive forward this research. Approach. A miniature wireless system weighing 8.5 g (including battery) was developed for rodent use that combined multichannel DBS and local-field potential (LFP) recordings. Its performance was verified in a working memory task that involved 4-channel fronto-hippocampal LFP recording and bilateral constant-current fimbria-fornix DBS. The system was synchronised with video-tracking for extraction of LFP at discrete task phases, and DBS was activated intermittently at discrete phases of the task. Main results. In addition to having a fast set-up time, the system could reliably transmit continuous LFP at over 8 hours across 3-5 m distances. During the working memory task, LFP pertaining to discrete task phases was extracted and compared with well-known neural correlates of active exploratory behaviour in rodents. DBS could be wirelessly activated/deactivated at any part of the experiment during EEG recording and transmission, allowing for a seamless integration of this modality. Significance. The wireless system combines a small size with a level of robustness and versatility that can greatly simplify rodent behavioural experiments involving EEG recording and DBS. Designed for versatility and simplicity, the small size and low-cost of the system and its receiver allow for enhanced portability, fast experimental setup times, and pave the way for integration with more complex behaviour.

  18. Peristaltic hemodynamic flow of couple stress fluid through a porous medium under the influence of magnetic field with slip effect

    NASA Astrophysics Data System (ADS)

    Swarnalathamma, B. V.; Krishna, M. Veera

    2016-05-01

    In this paper, we discussed the theoretical and computational study of peristaltic hemodynamic flow of couple stress fluids through a porous medium under the influence of magnetic field with wall slip condition. Actually this study is motivated towards the physiological flow of the blood in the micro circulatory system by taking account of the particle size effect. We consider the Reynolds number is small enough and the wave length to diameter ratio is large enough to negate inertial effects. The governing equations for the couple stress fluid flow through porous medium based on stoke constitutive equations and Brinkman model. The exact solutions for axial velocity, pressure gradient, frictional force, stream function and mechanical efficiency are obtained analytically, its behaviour computationally discussed with reference to different physical parameters reflecting couple stress parameter, Hartmann number, permeability parameter, slip parameter as well as amplitude ratio on pumping characteristics and frictional force, stream lines pattern and trapping of peristaltic flow pattern are studied with particular emphasis making use of graphs.

  19. 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

  20. 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.

  1. Chronic perchlorate exposure impairs stickleback reproductive behaviour and swimming performance

    PubMed Central

    Bernhardt, Richard R.; von Hippel, Frank A.

    2011-01-01

    Summary We describe behavioural changes in two generations of threespine stickleback (Gasterosteus aculeatus) exposed to environmentally relevant concentrations of perchlorate. The first generation (G0,2002) was exposed as two-year-old adults to perchlorate in experimental groups ranging in concentration from less than the method detection limit (<1.1 ppb) to 18.6 ppm for up to 22 days during their courtship, spawning, egg guarding, and first five days of fry guarding. No differences were noted in the behaviour or reproductive output of these fish that were exposed as adults. However, perchlorate exposure throughout development caused widespread effects in the second generation (G1,2003), which was spawned and raised through sexual maturity in one of four nominal experimental groups (0, 30 and 100 ppm, and a ‘variable’ treatment that progressively increased from <1.1 ppb to approximately 60 ppm perchlorate). Dose-dependent effects were found during the G1,2003’s swimming and behavioural evaluations, including higher mortality rates among treated fish following stressful events. Perchlorate-exposed fish had higher failure rates during swimming trials and failed at lower flow rates than control fish. A number of treated fish exhibited seizures. Progressively fewer males completed benchmark metrics, such as nest building, spawning, nursery formation, or fry production, in a dose-dependent manner. Fewer males from higher treatments courted females, and those that did initiated courtship later and had a reduced behavioural repertoire compared to fish from lower treatments. The lowest observed adverse effect level (LOAEL) for swimming performance, reproductive behaviour, survivorship and recruitment was 30 ppm perchlorate (our lowest G1,2003 treatment), and near complete inhibition of reproductive activity was noted among males raised in 100 ppm perchlorate. A small number of treated G1,2003 females were isolated in aquaria, and some performed reproductive

  2. 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.

  3. 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.

  4. Sparse repulsive coupling enhances synchronization in complex networks.

    PubMed

    Leyva, I; Sendiña-Nadal, I; Almendral, J A; Sanjuán, M A F

    2006-11-01

    Through the last years, different strategies to enhance synchronization in complex networks have been proposed. In this work, we show that synchronization of nonidentical dynamical units that are attractively coupled in a small-world network is strongly improved by just making phase-repulsive a tiny fraction of the couplings. By a purely topological analysis that does not depend on the dynamical model, we link the emerging dynamical behavior with the structural properties of the sparsely coupled repulsive network. PMID:17279973

  5. 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…

  6. 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.

  7. 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.

  8. 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.

  9. Enhancement of Compton scattering by an effective coupling constant

    SciTech Connect

    Barbiellini, Bernardo; Nicolini, Piero

    2011-08-15

    A robust thermodynamic argument shows that a small reduction of the effective coupling constant {alpha} of QED greatly enhances the low-energy Compton-scattering cross section and that the Thomson scattering length is connected to a fundamental scale {lambda}. A discussion provides a possible quantum interpretation of this enormous sensitivity to changes in the effective coupling constant {alpha}.

  10. Quantum Optical Signature of Plasmonically Coupled Nanocrystal Quantum Dots.

    PubMed

    Wang, Feng; Karan, Niladri S; Nguyen, Hue Minh; Mangum, Benjamin D; Ghosh, Yagnaseni; Sheehan, Chris J; Hollingsworth, Jennifer A; Htoon, Han

    2015-10-01

    Small clusters of two to three silica-coated nanocrystals coupled to plasmonic gap-bar antennas can exhibit photon antibunching, a characteristic of single quantum emitters. Through a detailed analysis of their photoluminescence emissions characteristics, it is shown that the observed photon antibunching is the evidence of coupled quantum dot formation resulting from the plasmonic enhancement of dipole-dipole interaction. PMID:26140499

  11. 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.

  12. 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.

  13. An extended version of the theory of planned behaviour: the role of self-efficacy and past behaviour in predicting the physical activity of Chinese adolescents.

    PubMed

    Wang, Lijuan; Zhang, Ying

    2016-01-01

    This study aimed to use an extended theory of planned behaviour (TPB), which incorporated additional self-efficacy and past behaviour, to predict the intention to engage in moderate-to-vigorous physical activity (MVPA) and the MVPA level of Chinese adolescents. Questionnaires that focused on MVPA, attitude, subjective norm, perceived behavioural control (PBC), self-efficacy and past behaviour related to the MVPA engagement were administered to a sample of 488 young people. Multiple regression analyses provided moderate support for TPB. Three TPB constructs predicted 28.7% of the variance in intentions to engage in MVPA, and that PBC, but not intention, explained 3.4% of the variance in MVPA. Self-efficacy significantly affected intention and behaviour over and above the influence of TPB. Past behaviour had a small but significant improvement in the prediction of intention, but no improvement in the prediction of MVPA. Based on the results, interventions should target adolescent self-efficacy and PBC in physical activity participation. PMID:26148128

  14. The role of behavioural heterogeneity on infection patterns: implications for pathogen transmission

    PubMed Central

    Dizney, Laurie; Dearing, M. Denise

    2013-01-01

    Animals infected with pathogens often differ in behaviour from their uninfected counterparts, and these differences may be key to understanding zoonotic pathogen transmission. To explore behavioural heterogeneity and its role in pathogen transmission, we studied deer mice, Peromyscus maniculatus, under field conditions. Deer mice are the natural host of Sin Nombre virus (SNV), a zoonotic pathogen with high human mortality. We live-trapped mice in May, July and September of 2009 and 2010, marked captures with passive integrated transponder (PIT) tags, recorded physical characteristics and collected blood samples for SNV analysis. For 4 nights after each trapping session, we observed behaviour with a novel surveillance system of nine camera stations, each consisting of a foraging tray, infrared camera, PIT antenna and data logger. We found that deer mice infected with SNV (30.0%) engaged more frequently in behaviours that increased the probability of intraspecific encounters and SNV transmission than did uninfected deer mice. When deer mice were categorized as bold (31.7%) or shy (68.3%) based on these behaviours, bold behaviour was predictive of positive SNV status. Bold deer mice were three times more likely to be infected with SNV than were shy deer mice. These results suggest that a small percentage of bold individuals are responsible for a majority of SNV transmission events, and that behavioural phenotype is an important consideration in transmission dynamics of zoonotic diseases. PMID:24319292

  15. Canine behaviour problems: discussions between veterinarians and dog owners during annual booster consultations.

    PubMed

    Roshier, A L; McBride, E A

    2013-03-01

    The veterinary profession recently acknowledged its responsibility to provide behaviour support, following criticism for focussing on the physiological aspects of welfare and overlooking the psychological. To further understand the practising of behavioural medicine, a 'fly-on-the-wall' approach was used to investigate welfare discussions during dog booster vaccinations. Seventeen consultations involving six veterinarians in two UK small-animal practices were videoed. Qualitative methods were used to analyse themes discussed and questionnaires completed to obtain participant information and perceptions. Five main topics of discussion were identified: navigation, medical, husbandry, behaviour and cost. Veterinarians led the discussion of all topics except behaviour which was instigated approximately equally by veterinarian and client. All clients reported one or more behaviours that were a concern to them, totalling 58 across the sample. Disconcertingly, only 10 were discussed during consultations and none fully explored nor managed beyond the consultation. Behaviour discussion varies between veterinarians; this may reflect their experience, confidence or clients' requests. Owners access welfare information from a variety of sources, not always from veterinarians. Where sources are not knowledgeable, both human and animal welfare can be seriously compromised. Veterinarians need to ensure that clients are enabled to discuss behaviour issues and are provided with appropriate support, be that in-house or via referral. PMID:23457279

  16. [Time trends in sex differences in adolescents' health behaviour from 2001 to 2010].

    PubMed

    Bucksch, J; Finne, E; Glücks, S; Kolip, P

    2012-07-01

    Health behaviours are influenced by gender-specific conceptions and norms of the society. These conceptions and norms are changing over time. The aim of this analysis is to describe gender differences in health behaviour of adolescents and to interpret these gender differences in terms of theories of social construction.We used the national German data of the Health-Behaviour in School-aged Children (HBSC) studies conducted in the years 2001/02, 2005/06 und 2009/10 with respect to the following health behaviours: tobacco use, binge drinking, diet, fruit and vegetable consumption, daily breakfast and physical activity. We describe the difference in frequencies between girls and boys and used a series of logistic regressions to test the significance of the gender difference in health behaviours with survey year as the predictor.There is only a small difference -between girls and boys with respect to tobacco use and binge drinking. For binge drinking girls nearly converge with the figures of boys. Relatively stable gender differences over time are existing for diet, nutrition and physical activity.From a theoretical gender perspective it might be possible that with respect to risky behaviours like tobacco use and alcohol consumption a clear gender specific connotation has changed over time. In other words risk behaviours become less important in presenting oneself as masculine. A gender sensible development of preventive interventions should consider the changes over time of gender-related -social constructions. PMID:22836893

  17. 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.

  18. 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.

  19. 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.

  20. Degradation behaviour of a new bioceramic: Ca2P2O7 with addition of Na4P2O7.10H2O.

    PubMed

    Lin, F H; Liao, C J; Chen, K S; Sun, J S; Liu, H C

    1997-07-01

    A newly produced bioceramic, beta-Ca2P2O7 with addition of Na4P2O7.10H2O (SDCP), has been implanted into the femoral condyle of rabbits. Within 6 weeks after implantation, most of the bioceramic is replaced by new woven bone. On the contrary, block from hydroxyapatite (HA) and beta-tricalcium phosphate (beta-TCP), which are osteoconductible, do not resorb within a short period of time. We believe that the biodegradable behaviour of SDCP may occur in two steps. The first and most important step is the digestion of particles and migration of the particles by phagocytosis. The object of this study is to examine the change in morphologies, chemical compositions and crystal structure of SDCP after soaking in distilled water for a certain period of time. The SDCP ceramic was also co-cultured with leucocytes to observe how the SDCP particles were digested by the leucocytes, so that the mechanism of biodegradable behaviour of SDCP ceramic in vivo might be clarified. Four types of sintered calcium phosphate ceramics were tested in the experiment: SDCP, pure beta-Ca2P2O7 (DCP), HA and beta-TCP. They wee soaked in distilled water at 37 degrees C for up to 30 days. The microstructure and morphology of crystals deposited on the surface were observed using scanning electron microscopy. Sodium, calcium and phosphorus ion contents in the supernatant solution were detected by atomic absorption analysis and ion coupled plasma. In summary, HA and DCP showed no significant evidence of dissolution in distilled water. In static distilled water, calcium ions may be released from beta-TCP into solution during the initial 7 days and then converted into HA by reprecipitation. The results showed that the SDCP was firstly dissolved into small grains or fragments by the solution. The small fragments should be so small as to be digested by the phagocytes in a physiological environment. PMID:9199761

  1. Neural coding of basic reward terms of animal learning theory, game theory, microeconomics and behavioural ecology.

    PubMed

    Schultz, Wolfram

    2004-04-01

    Neurons in a small number of brain structures detect rewards and reward-predicting stimuli and are active during the expectation of predictable food and liquid rewards. These neurons code the reward information according to basic terms of various behavioural theories that seek to explain reward-directed learning, approach behaviour and decision-making. The involved brain structures include groups of dopamine neurons, the striatum including the nucleus accumbens, the orbitofrontal cortex and the amygdala. The reward information is fed to brain structures involved in decision-making and organisation of behaviour, such as the dorsolateral prefrontal cortex and possibly the parietal cortex. The neural coding of basic reward terms derived from formal theories puts the neurophysiological investigation of reward mechanisms on firm conceptual grounds and provides neural correlates for the function of rewards in learning, approach behaviour and decision-making. PMID:15082317

  2. Behavioural hearing tactics: a controlled trial of a short treatment programme.

    PubMed

    Andersson, G; Green, M; Melin, L

    1997-06-01

    Nineteen elderly hearing impaired subjects participated in an experimental treatment study and received either behavioural hearing tactics or served as untreated controls. Treatment was supplied in the form of a self-help treatment manual supplied with telephone contacts during 4 consecutive weeks. The treatment manual included applied relaxation, communication strategies training, advice to relatives, information, and coping skills. Assessments (pre-post) were conducted in a structured interview measuring coping behaviour. In order to evoke behavioural compensation small acoustic provocations were included in the interview. Pre-post assessments also included questionnaires, daily registered hearing problems, and hours of daily hearing aid use. Results showed significant beneficial effects in favour of the treatment in terms of self-assessed problems and behaviour change. PMID:9159976

  3. The sum of the parts: can we really reduce carbon emissions through individual behaviour change?

    PubMed

    Reynolds, Lucy

    2010-01-01

    Individuals are increasingly being urged to 'do their bit' in the fight against climate change, with governments and pro-environmentalists insisting that the collective impact of small behaviour changes will result in a meaningful reduction in global carbon emissions. The following paper considers this debate, as well as offering personal contributions from two leading environmentalists: Dr Doug McKenzie-Mohr, environmental psychologist and author of Fostering Sustainable Behavior: Community-Based Social Marketing; and Dr Tom Crompton, change strategist for WWF and co-author of Meeting Environmental Challenges: The Role of Human Identity, who argues for the role of intrinsic value systems in achieving sustainable behaviour change. As well as considering the responsibility of the individual in mitigating climate change, the paper introduces the discipline of social marketing as an effective tool for facilitating individual behaviour change, drawing on evidence from the field to recommend the key characteristics of effective behaviour change programmes. PMID:20333949

  4. Clustering Analysis of OFFICER'S Behaviours in London Police Foot Patrol Activities

    NASA Astrophysics Data System (ADS)

    Shen, J.; Cheng, T.

    2015-07-01

    In this small paper we aim at presenting a framework of conceptual representation and clustering analysis of police officers' patrol pattern obtained from mining their raw movement trajectory data. This have been achieved by a model developed to accounts for the spatio-temporal dynamics human movements by incorporating both the behaviour features of the travellers and the semantic meaning of the environment they are moving in. Hence, the similarity metric of traveller behaviours is jointly defined according to the stay time allocation in each Spatio-temporal region of interests (ST-ROI) to support clustering analysis of patrol behaviours. The proposed framework enables the analysis of behaviour and preferences on higher level based on raw moment trajectories. The model is firstly applied to police patrol data provided by the Metropolitan Police and will be tested by other type of dataset afterwards.

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. Perturbative Critical Behavior from Spacetime Dependent Couplings

    SciTech Connect

    Dong, Xi; Horn, Bart; Silverstein, Eva; Torroba, Gonzalo

    2012-08-03

    We find novel perturbative fixed points by introducing mildly spacetime-dependent couplings into otherwise marginal terms. In four-dimensional QFT, these are physical analogues of the small-{epsilon} Wilson-Fisher fixed point. Rather than considering 4-{epsilon} dimensions, we stay in four dimensions but introduce couplings whose leading spacetime dependence is of the form {lambda}x{sup {kappa}}{mu}{sup {kappa}}, with a small parameter {kappa} playing a role analogous to {epsilon}. We show, in {phi}{sup 4} theory and in QED and QCD with massless flavors, that this leads to a critical theory under perturbative control over an exponentially wide window of spacetime positions x. The exact fixed point coupling {lambda}{sub *}(x) in our theory is identical to the running coupling of the translationally invariant theory, with the scale replaced by 1/x. Similar statements hold for three-dimensional {phi}{sup 6} theories and two-dimensional sigma models with curved target spaces. We also describe strongly coupled examples using conformal perturbation theory.

  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. Computational Investigation of the Influence of Fly Ash Silica Content and Shape on the Erosion Behaviour of Indian Coal Fired Boiler Grade Steels

    NASA Astrophysics Data System (ADS)

    Kumari, Amrita; Das, Suchandan Kumar; Srivastava, Prem Kumar

    2016-07-01

    A mathematical model has been developed to characterize the erosion behaviour of fly ash on boiler grade steel surfaces incorporating various ductile erosion mechanisms. These mechanisms constitute cutting wear, repeated plastic deformation and effect of operating temperature on the mechanical properties of the substrate. Parametric analysis has been carried out to study the erosion response of some typical steel grades as a function of particle impact parameters such as particle impact velocity, angle of impingement coupled with the effect of temperature on the tensile properties. Further, effects of fly ash properties such as hardness (silica content) and shape (angularity) on the erosion response have been also investigated along with the ballistic parameters. These investigations show that a small increment in the fly ash hardness can considerably augment the erosion rate of the steel surface under a given particle impingement condition. This vindicates that hardness of fly ash is one of the most critical parameter which has a direct impact in enhancing the erosion rate of boiler grade steels. The effect of fly ash shape on the erosion behaviour is also studied in conjunction with the particle hardness. This shows that the composite action of these parameters augment the erosion rate significantly.

  13. 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

  14. 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

  15. 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

  16. 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

  17. [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

  18. 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

  19. 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…

  20. Chaotic burst synchronization in a two-small-world-layer neuronal network

    NASA Astrophysics Data System (ADS)

    Zheng, Yanhong; Wang, Haixia

    2015-09-01

    Chaotic burst synchronization in a two-small-world-layer neuronal network is studied in this paper. For a neuronal network coupled by two single-small-world-layer networks with link probability differences between layers, the two-layer network can achieve synchrony as the interlayer coupling strength increases. When chaotic layer network is coupled with chaotic-burst-synchronization layer network, the latter is dominant at small interlayer coupling strength, so it can make the layer with the irregular pattern show some regular and also exhibit the same pattern with the other layer. However, when chaotic layer is coupled with firing synchronization layer, the ordered layer is dominated by a disordered one with the interlayer coupling strength increasing. When the interlayer coupling strength is large enough, both networks are chaotic burst synchronization. Therefore, the synchronous states strongly depend on the interlayer coupling strength and the link probability. Moreover, the spatiotemporal pattern synchronization between the networks is robust to small noise.