3,190 research outputs found
Social learning mechanisms compared in a simple environment
Social learning can be adaptive, but little is known about the underlying mechanisms. Many researchers have focused on imitation but this may have led to simpler mechanisms being underestimated. We demonstrate in simulation that imitative learning is not always the best strategy for a group-living animal, and that the effectiveness of any such strategy will depend on details of the environment and the animal's lifestyle. We show that observations of behavioural convergence or "traditions" might suggest effective social learning, but are meaningless considered alone
Effects of the topology of social networks on information transmission
Social behaviours cannot be fully understood without considering the network structures that underlie them. Developments in network theory provide us with relevant modelling tools. The topology of social networks may be due to selection for information transmission. To investigate this, we generated network topologies with varying proportions of random connections and degrees of preferential attachment. We simulated two social tasks on these networks: a spreading innovation model and a simple market. Results indicated that non-zero levels of random connections and low levels of preferential attachment led to more efficient information transmission. Theoretical and practical implications are discussed
The impact of space and space-related activities on a local economy. a case study of boulder, colorado. part ii- the income-product accounts
Total impact of space and space related activities on local economy of Boulder, Colorado - income-product account
Spatial and temporal patterns of land surface fluxes from remotely sensed surface temperatures within an
International audienceCharacterising the development of evapotranspiration through time is a difficult task, particularly when utilising remote sensing data, because retrieved information is often spatially dense, but temporally sparse. Techniques to expand these essentially instantaneous measures are not only limited, they are restricted by the general paucity of information describing the spatial distribution and temporal evolution of evaporative patterns. In a novel approach, temporal changes in land surface temperatures, derived from NOAA-AVHRR imagery and a generalised split-window algorithm, are used as a calibration variable in a simple land surface scheme (TOPUP) and combined within the Generalised Likelihood Uncertainty Estimation (GLUE) methodology, to provide estimates of areal evapotranspiration at the pixel scale. Such an approach offers an innovative means of transcending the patch or landscape scale of SVAT type models, to spatially distributed estimates of model output. The resulting spatial and temporal patterns of land surface fluxes and surface resistance are used to more fully understand the hydro-ecological trends observed across a study catchment in eastern Australia. The modelling approach is assessed by comparing predicted cumulative evapotranspiration values with surface fluxes determined from Bowen ratio systems and using auxiliary information such as in-situ soil moisture measurements and depth to groundwater to corroborate observed responses
Spatial and temporal patterns of land surface fluxes from remotely sensed surface temperatures within an uncertainty modelling framework
Characterising the development of evapotranspiration through time is a difficult task, particularly when utilising remote sensing data, because retrieved information is often spatially dense, but temporally sparse. Techniques to expand these essentially instantaneous measures are not only limited, they are restricted by the general paucity of information describing the spatial distribution and temporal evolution of evaporative patterns. In a novel approach, temporal changes in land surface temperatures, derived from NOAA-AVHRR imagery and a generalised split-window algorithm, are used as a calibration variable in a simple land surface scheme (TOPUP) and combined within the Generalised Likelihood Uncertainty Estimation (GLUE) methodology to provide estimates of areal evapotranspiration at the pixel scale. Such an approach offers an innovative means of transcending the patch or landscape scale of SVAT type models, to spatially distributed estimates of model output. The resulting spatial and temporal patterns of land surface fluxes and surface resistance are used to more fully understand the hydro-ecological trends observed across a study catchment in eastern Australia. The modelling approach is assessed by comparing predicted cumulative evapotranspiration values with surface fluxes determined from Bowen ratio systems and using auxiliary information such as in-situ soil moisture measurements and depth to groundwater to corroborate observed responses
Thermodynamic behaviour and structural properties of an aqueous sodium chloride solution upon supercooling
We present the results of a molecular dynamics simulation study of
thermodynamic and structural properties upon supercooling of a low
concentration sodium chloride solution in TIP4P water and the comparison with
the corresponding bulk quantities. We study the isotherms and the isochores for
both the aqueous solution and bulk water. The comparison of the phase diagrams
shows that thermodynamic properties of the solution are not merely shifted with
respect to the bulk. Moreover, from the analysis of the thermodynamic curves,
both the spinodal line and the temperatures of maximum density curve can be
calculated. The spinodal line appears not to be influenced by the presence of
ions at the chosen concentration, while the temperatures of maximum density
curve displays both a mild shift in temperature and a shape modification with
respect to bulk. Signatures of the presence of a liquid-liquid critical point
are found in the aqueous solution. By analysing the water-ion radial
distribution functions of the aqueous solution we observe that upon changing
density, structural modifications appear close to the spinodal. For low
temperatures additional modifications appear also for densities close to that
corresponding to a low density configurational energy minimum.Comment: 10 pages, 13 figures, 2 tables. To be published in J. Chem. Phy
Spectral Signatures of the Diffusional Anomaly in Water
Analysis of power spectrum profiles for various tagged particle quantities in
bulk SPC/E water is used to demonstrate that variations in mobility associated
with the diffusional anomaly are mirrored in the exponent of the \onebyf\
region. Monitoring of \onebyf behaviour is shown to be a simple and direct
method for linking phenomena on three distinctive length and time scales: the
local molecular environment, hydrogen bond network reorganisations and the
diffusivity. The results indicate that experimental studies of supercooled
water to probe the density dependence of spectral features, or
equivalent stretched exponential behaviour in time-correlation functions, will
be of interest.Comment: 5 Pages, 4 Figure
Community psychology as a process of citizen participation in health policy: Comment on “the rise of post-truth populism in pluralist liberal democracies: Challenges for health policy”
This brief commentary discusses a recent paper by Speed and Mannion that explores “The Rise of post truth populism in liberal democracies: challenges for health policy.” It considers their assertion that through meaningful democratic engagement in health policy, some of the risks brought about by an exclusionary populist politics can be mediated. With an overview of what participation means in modern healthcare policy and implementation, the field of community psychology is presented as one way to engage marginalized groups at risk of exploitation or exclusion by nativist populist policy
Multiphase modelling of tumour growth and extracellular matrix interaction: mathematical tools and applications
Resorting to a multiphase modelling framework, tumours are described here as a mixture of tumour and host cells within a porous structure constituted by a remodelling extracellular matrix (ECM), which is wet by a physiological extracellular fluid. The model presented in this article focuses mainly on the description of mechanical interactions of the growing tumour with the host tissue, their influence on tumour growth, and the attachment/detachment mechanisms between cells and ECM. Starting from some recent experimental evidences, we propose to describe the interaction forces involving the extracellular matrix via some concepts coming from viscoplasticity. We then apply the model to the description of the growth of tumour cords and the formation of fibrosis
- …