Hamming distance and mobility behavior in generalized rock-paper-scissors models

This work reports on two related investigations of stochastic simulations which are widely used to study biodiversity and other related issues. We first deal with the behavior of the Hamming distance under the increase of the number of species and the size of the lattice, and then investigate how the mobility of the species contributes to jeopardize biodiversity. The investigations are based on the standard rules of reproduction, mobility and predation or competition, which are described by specific rules, guided by generalization of the rock-paper-scissors game, valid in the case of three species. The results on the Hamming distance indicate that it engenders universal behavior, independently of the number of species and the size of the square lattice. The results on the mobility confirm the prediction that it may destroy diversity, if it is increased to higher and higher values.Comment: 7 pages, 9 figures. To appear in EP

A theoretical description of energy spectra and two-neutron separation energies for neutron-rich zirconium isotopes

Very recently the atomic masses of neutron-rich Zr isotopes, from $^{96}$Zr to $^{104}$Zr, have been measured with high precision. Using a schematic Interacting Boson Model (IBM) Hamiltonian, the evolution from spherical to deformed shapes along the chain of Zr isotopes, describing at the same time the excitation energies as well as the two-neutron separation energies, can be rather well reproduced. The interplay between phase transitions and configuration mixing of intruder excitations in this mass region is succinctly addressed.Comment: Accepted in European Journal of Physics

Shear-melting of a hexagonal columnar crystal by proliferation of dislocations

A hexagonal columnar crystal undergoes a shear-melting transition above a critical shear rate or stress. We combine the analysis of the shear-thinning regime below the melting with that of synchrotron X-ray scattering data under shear and propose the melting to be due to a proliferation of dislocations, whose density is determined by both techniques to vary as a power law of the shear rate with a 2/3 exponent, as expected for a creep model of crystalline solids. Moreover, our data suggest the existence under shear of a line hexatic phase, between the columnar crystal and the liquid phase

Alterações morfológicas e crescimento de duas espécies gramíneas sob alagamento.

Este trabalho objetivou investigar as respostas morfológicas e o crescimento de Brachiaria brizantha e Paspalum fasciculatum cultivadas durante 21 dias sob condições de alagamento. A baixa disponibilidade de oxigênio devido ao alagamento reduziu significativamente as taxas de crescimento relativo e assimilatória líquida de B. brizantha, assim como a alocação de biomassa para raízes, aos 14 dias de alagamento. Em P. fasciculatum, as reduções das taxas e da alocação de biomassa foram significativas somente aos 21 dias de alagamento. Nas espécies estudadas, as adaptações morfológicas foram claramente evidenciadas com a formação de grande quantidade de raízes adventícias, que provavelmente contribuíram para a sobrevivência das mesmas à hipóxia. Estes resultados indicam que a espécie P. fasciculatum é mais tolerante ao alagamento quando comparada com B. brizantha

Divergence-type 2+1 dissipative hydrodynamics applied to heavy-ion collisions

We apply divergence-type theory (DTT) dissipative hydrodynamics to study the 2+1 space-time evolution of the fireball created in Au+Au relativistic heavy-ion collisions at $\sqrt{s_{NN}}=$200 GeV. DTTs are exact hydrodynamic theories that do no rely on velocity gradient expansions and therefore go beyond second-order theories. We numerically solve the equations of motion of the DTT for Glauber initial conditions and compare the results with those of second-order theory based on conformal invariants (BRSS) and with data. We find that the charged-hadron minumum-bias elliptic flow reaches its maximum value at lower $p_T$ in the DTT, and that the DTT allows for a value of $\eta/s$ slightly larger than that of the BRSS. Our results show that the differences between viscous hydrodynamic formalisms are a significant source of uncertainty in the precise extraction of $\eta/s$ from experiments.Comment: v4: 29 pages, 12 figures, minor changes. Final version as published in Phys. Rev.

Internet use by middle-aged and older adults: Longitudinal relationships with functional ability, social support, and self-perceptions of aging

In an increasingly digital world, those who remain offline may face greater challenges across multiple contexts of everyday life. Besides being less likely to be internet users, older age groups go online less frequently and for fewer activities. Understanding which factors facilitate or prevent internet use in later life is therefore essential to minimize existing age-based digital inequalities. Based on the 2014 and 2017 waves of the German Ageing Survey, comprising 3,479 respondents aged 40 years and older, this study examined the longitudinal relationships of a wide range of often overlooked, yet potentially relevant factors related to functional ability, social support, and self-perceptions of aging with general internet use and seven specific online behaviors. As the only factors relating to general use and a considerable number of specific uses, cognitive functioning and competence-related self-perceptions of aging emerged as the most important correlates of internet use in middle and late adulthood. Better cognitive functioning preceded contacting friends, acquaintances, and relatives, searching for information, banking, and shopping more frequently 3 years later. In turn, competence self-perceptions of aging preceded contacting others, searching for new social contacts, seeking information, banking, engaging in online entertainment, and creating contents more frequently 3 years later. Reciprocal relationships were also found between each factor and general use, suggesting mutual influences. Additionally, physical functioning and received informational support preceded greater use for specific activities. These findings elucidate which factors to consider when developing effective strategies to promote general and specific internet use among middle-aged and older adults.info:eu-repo/semantics/acceptedVersio

Avaliação de caracteres do fruto do híbrido de coqueiro Anão Verde do Brasil de Una X Gigante do oeste africano.

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Estoque de carbono na serapilheira de cultivos de palma de óleo em sistemas agroflorestais na Amazônia Oriental.

O objetivo do trabalho foi avaliar o estoque de carbono na serapilheira em cultivo de palma de óleo em sistemas agroflorestais. O estudo foi realizado no município de Tomé-Açu (PA), em área de agricultor familiar. Dois sistemas de cultivo de palma de óleo foram avaliados, sendo um mais diversificado (Biodiverso) e outro menos (Adubadeiras); estes sistemas foram comparados com uma área de referência representada por uma floresta secundária de aproximadamente 16 anos de idade. As amostras foram coletadas usando-se uma grade metálica cortante com área interna de 0,25 m² em 10 pontos em cada parcela, representados por área de influencia do dendê (D), na entre linhas do dendê ou carreador (C), no enleiramento de resíduos da cultura (E), nas linhas e entrelinhas das outras espécies do SAF (S). As amostras foram processadas e separadas nas seguintes frações: folhas, lenhoso &#8805; 2 mm, lenhoso < 2 mm, miscelânea. Comparando os sistemas o estoque de carbono foi máximo na fração folha com maior média total (1,8625 Mg C ha-1) para floresta sucessional; as frações lenhosa &#8805; 2 mm e miscelânea foram as que apresentaram maior estoque de carbono nos três tratamento