8,029 research outputs found
Collapse transition in polymer models with multiple monomers per site and multiple bonds per edge
We present results from extensive Monte Carlo simulations of polymer models
where each lattice site can be visited by up to monomers and no restriction
is imposed on the number of bonds on each lattice edge. These \textit{multiple
monomer per site} (MMS) models are investigated on the square and cubic
lattices, for and , by associating Boltzmann weights ,
and to sites visited by 1, 2 and
3 monomers, respectively. Two versions of the MMS models are considered for
which immediate reversals of the walks are allowed (RA) or forbidden (RF). In
contrast to previous simulations of these models, we find the same
thermodynamic behavior for both RA and RF versions. In three-dimensions, the
phase diagrams - in space - are featured by coil and
globule phases separated by a line of points, as thoroughly
demonstrated by the metric , crossover and entropic
exponents. The existence of the -lines is also confirmed by the second
virial coefficient. This shows that no discontinuous collapse transition exists
in these models, in contrast to previous claims based on a weak bimodality
observed in some distributions, which indeed exists in a narrow region very
close to the -line when . Interestingly, in
two-dimensions, only a crossover is found between the coil and globule phases
Universality class of the special adsorption point of two-dimensional lattice polymers.
In recent work [Rodrigues et al., Phys. Rev. E 100, 022121 (2019)10.1103/PhysRevE.100.022121], evidence was found that the surface adsorption transition of interacting self-avoiding trails (ISATs) placed on the square lattice displays a nonuniversal behavior at the special adsorption point (SAP) where the collapsing polymers adsorb. In fact, different surface exponents ϕ^{(s)} and 1/δ^{(s)} were found at the SAP depending on whether the surface orientation is horizontal (HS) or diagonal (DS). Here, we revisit these systems and study other ones, through extensive Monte Carlo simulations, considering much longer trails than previous works. Importantly, we demonstrate that the different exponents observed in the reference above are due to the presence of a surface-attached-globule (SAG) phase in the DS system, which changes the multicritical nature of the SAP and is absent in the HS case. By considering a modified horizontal surface (mHS), on which the trails are forbidden from having two consecutive steps, resembling the DS situation, a stable SAG phase is found in the phase diagram, and both DS and mHS systems present similar 1/δ^{(s)} exponents at the SAP, namely, 1/δ^{(s)}≈0.44, whereas 1/δ^{(s)}≈0.34 in the HS case. Intriguingly, while ϕ^{(s)}≈1/δ^{(s)} is found for the DS and HS scenarios, as expected, in the mHS case ϕ^{(s)} is about 10% smaller than 1/δ^{(s)}. These results strongly indicate that at least two universality classes exist for the SAPs of adsorbing ISATs on the square lattice
Beyond onboard sensors in robotic swarms: Local collective sensing through situated communication
The constituent robots in swarm robotics systems are typically equipped with relatively simple, onboard sensors of limited quality and range. When robots have the capacity to communicate with one another, communication has so far been exclusively used for coordination. In this paper, we present a novel approach in which
local, situated communication is leveraged to overcome the sensory limitations of the individual robots. In
our approach, robots share sensory inputs with neighboring robots, thereby effectively extending each other’s
sensory capabilities. We evaluate our approach in a series of experiments in which we evolve controllers for
robots to capture mobile preys. We compare the performance of (i) swarms that use our approach, (ii) swarms
in which robots use only their limited onboard sensors, and (iii) swarms in which robots are equipped with
ideal sensors that provide extended sensory capabilities without the need for communication. Our results show
that swarms in which local communication is used to extend the sensory capabilities of the individual robots
outperform swarms in which only onboard sensors are used. Our results also show that in certain experimental
configurations, the performance of swarms using our approach is close to the performance of swarms with
ideal sensors.info:eu-repo/semantics/acceptedVersio
“O homem veio do macaco?” o que pensam os alunos da 3ª série do ensino médio sobre a evolução humana
Com o intuito de subsidiar desenvolvimento de estratégias de ensino, capazes de favorecer uma aprendizagem que auxilie o aluno a compreender os conceitos referentes à Evolução Biológica, bem como proporcionar meios para que os alunos compreendam a Evolução Biológica como um processo dinâmico e como elemento unificador dos conhecimentos biológicos, foi feito uma pesquisa dos conhecimentos prévios que alunos da 3ª série do ensino médio possuíam sobre evolução humana. Os achados indicam que mesmo aceitando o evolucionismo como teoria, os estudantes confundem as teorias evolutivas como o lamarckismo e o darwinismo. 21% das respostas expressas pelos sujeitos apresentam uma conciliação entre a visão evolutiva cientifica e a visão judaico-cristã da Criação, na qual os alunos apresentam uma tendência à visão criacionista
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