Search results for "models"
showing 10 items of 8211 documents
GPU accelerated Monte Carlo simulations of lattice spin models
2011
We consider Monte Carlo simulations of classical spin models of statistical mechanics using the massively parallel architecture provided by graphics processing units (GPUs). We discuss simulations of models with discrete and continuous variables, and using an array of algorithms ranging from single-spin flip Metropolis updates over cluster algorithms to multicanonical and Wang-Landau techniques to judge the scope and limitations of GPU accelerated computation in this field. For most simulations discussed, we find significant speed-ups by two to three orders of magnitude as compared to single-threaded CPU implementations.
Neutron halos in the excited states of 12B
2018
The differential cross sections of the 11B(d,p) 12B reaction leading to formation of the 1+ ground state and the 0.95-MeV 2+, 1.67-MeV 2−, 2.62-MeV 1−, 2.72-MeV 0+, and 3.39-MeV 3− excited states of 12B are measured at Ed = 21.5 MeV. The analysis of the data is carried out within the coupled-reaction-channels method for the direct neutron transfer and the Hauser-Feshbach formalism of the statistical compound-nucleus model. The spectroscopic factors, asymptotic normalization coefficients, and rms radii of the last neutron in all states studied are deduced. The existence of the neutron halos in the 1.67-MeV 2− and 2.62-MeV 1− states is found, consistent with the earlier published data. New in…
Modelling the evolution of cognitive styles.
2019
Abstract Individuals consistently differ in behaviour, exhibiting so-called personalities. In many species, individuals differ also in their cognitive abilities. When personalities and cognitive abilities occur in distinct combinations, they can be described as ‘cognitive styles’. Both empirical and theoretical investigations produced contradicting or mixed results regarding the complex interplay between cognitive styles and environmental conditions. Here we use individual-based simulations to show that, under just slightly different environmental conditions, different cognitive styles exist and under a variety of conditions, can also co-exist. Co-existences are based on individual speciali…
CHANGING PERSPECTIVE ON PERCEPTION PHYSIOLOGY: CAN YOU REALLY SEE WHAT IS HAPPENING?
2018
Perception is a complex, neural mechanism that requires organization and interpretation of input meaning and it has been a key topic in medicine, neuroscience and philosophy for centuries. Gestalt psychology proposed that the underlying mechanism is a constructive process that depends on both input of stimuli and the sensory-motor state of the agent. The Bayesian Brain hypothesis reframed it as probabilistic inference of previous beliefs, which are revised to accommodate new information. The Predictive Coding Theory proposes that this process is implemented through a top-down cascade of cortical predictions of lower level input and the concurrent propagation of a bottom-up prediction error …
Truth Demystified
2015
For further development, see Karlis Podnieks in ResearchGate. How could we recognize truth, if we only have models, means of model-building, and the history of their evolution? Where is the truth in the cloud of models – with so many of them already gone with the wind? We can define truths as more or less persistent invariants of successful evolution of models and means of model-building. What is true, will not change in the future (for some time, at least). This approach to truth could be named demystified realism (or, demystified theory of truth) – the kind of realism based on a minimum of metaphysical assumptions. (“Robotic realism” also would be appropriate, but the term is occupied alr…
Gestalt Theory, Data Decomposition and Functional Architecture in Visual Neuroscience
2013
Classical and recent result about neuronal properties, and their functions and architectural design prompted claims to bring gestalt theory to bear on neurosciences reserach. It is deemed to contribute to understand brain mechanism through descriptions of visual functions expected to be wired in the brain. The standard models of data decomposition and functional architecture in visual neuroscience are discussed. Such issues as visual primitives identification and neuronal activity integration in gestaltist terms are introduced.
Northward range expansion requires synchronization of both overwintering behaviour and physiology with photoperiod in the invasive Colorado potato be…
2014
Abstract. Photoperiodic phenological adaptations are prevalent in many organisms living in seasonal environments. As both photoperiod and growth season length change with latitude, species undergoing latitudinal range expansion often need to synchronize their life cycle with a changing photoperiod and growth season length. Since adaptive synchronization often involves a large number of time-consuming genetic changes, behavioural plasticity might be a faster way to adjust to novel conditions. We compared behavioural and physiological traits in overwintering (diapause) preparation in three latitudinally different European Colorado potato beetle (Leptinotarsa decemlineata) populations reared u…
Zebrafish Fins as a Model System for Skeletal Human Studies
2007
Recent studies on the morphogenesis of the fins ofDanio rerio(zebrafish) during development and regeneration suggest that a number of inductive signals involved in the process are similar to some of those that affect bone and cartilage differentiation in mammals and humans. Akimenko et al. (2002) has shown that bone morphogenetic protein-2b (BMP2b) is involved in the induction of dermal bone differentiation during fin regeneration. Many other groups have also shown that molecules from the transforming growth factor-beta superfamily (TGFβ), including BMP2, are effective in promoting chondrogenesis and osteogenesisin vivoin higher vertebrates, including humans. In the present study, we review…
Temperature dependence of η / s of strongly interacting matter: Effects of the equation of state and the parametric form of ( η / s ) ( T )
2020
We investigate the temperature dependence of the shear viscosity to entropy density ratio η/s using a piecewise linear parametrization. To determine the optimal values of the parameters and the associated uncertainties, we perform a global Bayesian model-to-data comparison on Au+Au collisions at √sNN=200 GeV and Pb+Pb collisions at 2.76 TeV and 5.02 TeV, using a 2+1D hydrodynamical model with the Eskola-Kajantie-Ruuskanen-Tuominen (EKRT) initial state. We provide three new parametrizations of the equation of state (EoS) based on contemporary lattice results and hadron resonance gas, and use them and the widely used s95p parametrization to explore the uncertainty in the analysis due to the c…
Les modèles de communication des sciences et techniques, révélateurs de postures publiques
2012
In addition to the famous deficit and contextual models scientific literature on science communication offers a wide variety of models, seen as mental, textual or pictural representations, helpful to describe, to explain, to analyze, to act. The models I found can be listed by themes: institutional questions, cultural visions, mediation, mass media, epistemology, teaching tools, advertising... Then, the pervasiveness of deficit and contextual models in the meetings dealing with scientific culture can be analyzed as a focus on institutional concerns, based on the need of effective communication ways. But exploring the models utilized by science communication scholarships, in all their multif…