28,975 research outputs found
Zero-temperature TAP equations for the Ghatak-Sherrington model
The zero-temperature TAP equations for the spin-1 Ghatak-Sherrington model
are investigated. The spin-glass energy density (ground state) is determined as
a function of the anisotropy crystal field for a large number of spins.
This allows us to locate a first-order transition between the spin-glass and
paramagnetic phases within a good accuracy. The total number of solutions is
also determined as a function of .Comment: 11 pages, 2 ps figures include
Effects of Random Biquadratic Couplings in a Spin-1 Spin-Glass Model
A spin-1 model, appropriated to study the competition between bilinear
(J_{ij}S_{i}S_{j}) and biquadratic (K_{ij}S_{i}^{2}S_{j}^{2}) random
interactions, both of them with zero mean, is investigated. The interactions
are infinite-ranged and the replica method is employed. Within the
replica-symmetric assumption, the system presents two phases, namely,
paramagnetic and spin-glass, separated by a continuous transition line. The
stability analysis of the replica-symmetric solution yields, besides the usual
instability associated with the spin-glass ordering, a new phase due to the
random biquadratic couplings between the spins.Comment: 16 pages plus 2 ps figure
Optics and children
Light and Optics are subjects that “naturally” attracts the interest and sympathy of
children even from very early ages. In this communication, we present a serie of experiments
and support material designed in this hands-on perspective, to be used to introduce the study of
light and optics to kindergarten and early basic school students. Our hands-on investigative
approach leads the students, aged 4 to 10 years, to observe the experiment and discover
themselves, in a critical and active way, different aspects of light and optics. Preparing funny
eye catching situations and experiments predispose the children to work, effectively, enjoying
themselves while building up their self-confidence.(undefined
Características das principais variedades de café cultivadas em Rondônia.
O presente trabalho tem como objetivo relacionar e descrever, sucintamente, as principais variedades de café indicadas para cultivo comercial no Estado de Rondônia.bitstream/item/54346/1/Doc93-cafe.pd
Doenças da bananicultura: mal-do-panamá.
No Brasil, esta doença foi oficialmente constatada no ano de 1930, no Município de Piracicaba, São Paulo, atacando principalmente a cultivar Maçã. Atualmente, a doença pode ser encontrada em praticamente quase todo o território nacional, atacando, na maioria das vezes, a cultivar Maçã. Dada sua ampla distribuição, esta doença merece especial atenção e vêm ganhando importância, tanto em nível nacional como no exterior, visto que relatos assinalam sua ocorrência em praticamente todas as áreas produtoras de banana, atingindo, inclusive, bananas do subgrupo Cavendish.bitstream/item/24671/1/ct86-maldopanama.pd
Doenças da bananicultura: sigatoca-amarela.
No Brasil, a sigatoca-amarela foi inicialmente detectada em 1935, na cidade de São Sebastião-SP, porém ganhou importância em 1944, no Amazonas. Atualmente, encontra-se disseminada por praticamente todo o país. Entretanto, a doença apresenta maior relevância nas regiões ou microregiões de clima úmido, com alta pluviosidade e temperaturas por volta dos 25 °C.bitstream/item/24670/1/ct85-sigatoca-amarela.pd
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