1,585 research outputs found
Torsion-Adding and Asymptotic Winding Number for Periodic Window Sequences
In parameter space of nonlinear dynamical systems, windows of periodic states
are aligned following routes of period-adding configuring periodic window
sequences. In state space of driven nonlinear oscillators, we determine the
torsion associated with the periodic states and identify regions of uniform
torsion in the window sequences. Moreover, we find that the measured of torsion
differs by a constant between successive windows in periodic window sequences.
We call this phenomenon as torsion-adding. Finally, combining the torsion and
the period adding rules, we deduce a general rule to obtain the asymptotic
winding number in the accumulation limit of such periodic window sequences
Caracterização de genótipos de pinhão manso do banco ativo de germoplasma da embrapa algodão.
Efeitos da desidratação e do armazenamento em sementes de Taluma ovata St. Hill. - magnoliaceae.
Resumo
Aspects of U-duality in BLG models with Lorentzian metric 3-algebras
In our previous paper, it was shown that BLG model based on a Lorentzian
metric 3-algebra gives Dp-brane action whose worldvolume is compactified on
torus T^d (d=p-2). Here the 3-algebra was a generalized one with d+1 pairs of
Lorentzian metric generators and expressed in terms of a loop algebra with
central extensions. In this paper, we derive the precise relation between the
coupling constant of the super Yang-Mills, the moduli of T^d and some R-R flux
with VEV's of ghost fields associated with Lorentzian metric generators. In
particular, for d=1, we derive the Yang-Mills action with theta term and show
that SL(2,Z) Montonen-Olive duality is realized as the rotation of two VEV's.
Furthermore, some moduli parameters such as NS-NS 2-form flux are identified as
the deformation parameters of the 3-algebras. By combining them, we recover
most of the moduli parameters which are required by U-duality symmetry.Comment: 27 pages, v2: minor correction
Fitting Brazilian livestock production to changes in natural and political environments.
Cattle production is the human activity with largest land use. Rises in demand for cattle products and steady or lower grasslands availability are projected, impelling high rates of productivity gain. However, greater pasture production seasonality in the main producing regions will challenge exclusive pasture-fed production in Brazil. Recovery of degraded pastureland, increasing feed supplementation and feedlots, and integration of livestock production with annual crops, forestry and ethanol agroindustry are promising strategies sustainable intensification under climate change. Digital transformation empowers society to influence public policies and products chains, rapidly changing production constraints and increasing demand for information from production systems. In this context, reducing vulnerability in the international market will demand national institutions and research teams to take part on international initiatives to produce new metrics, models, methods and analysis, which have the potential to affect the cattle industry. Lack of digital literacy of smallholder farmers in remote areas is also seen as an vulnerability, because of their reduced capacity to respond to this new connected environment
Half-BPS quotients in M-theory: ADE with a twist
We classify Freund-Rubin backgrounds of eleven-dimensional supergravity of
the form AdS_4 x X^7 which are at least half BPS; equivalently, smooth
quotients of the round 7-sphere by finite subgroups of SO(8) which admit an
(N>3)-dimensional subspace of Killing spinors. The classification is given in
terms of pairs consisting of an ADE subgroup of SU(2) and an automorphism
defining its embedding in SO(8). In particular we find novel half-BPS quotients
associated with the subgroups of type D_n (for n>5), E_7 and E_8 and their
outer automorphisms.Comment: 16 pages; V2: notational inconsistencies addressed, final version to
be published in JHE
Extração, secagem e beneficiamento de sementes de espécies florestais nativas.
Organizado por Patricia Póvoa de Mattos, Celso Garcia Auer, Rejane Stumpf Sberze, Katia Regina Pichelli e Paulo César Botosso
Estrutura da comunidade vegetal arbóreo-arbustiva de um sistema agrossilvipastoril, em Sobral, CE.
A Caatinga, vegetação dominante no semiárido brasileiro, vem sofrendo intenso processo de degradação, provocado, entre outras causas, pelas atividades tradicionais agropecuárias e extrativistas. A necessidade de conservar o meio ambiente e seus recursos naturais ocasionou a busca por alternativas aos sistemas convencionais de produção. Neste contexto, os sistemas agroflorestais, que integram árvores com culturas agrícolas e produção animal, surgem como alternativa de exploração com sustentabilidade. Com o objetivo de estudar o potencial de preservação de espécies da flora da Caatinga em um sistema agrossilvipastoril implantado no semiárido, em Sobral - CE, foi avaliada a densidade, a frequência e a dominância relativas, o índice do valor de importância e o índice de Shannon & Wiener, no componente arbóreo-arbustivo deste sistema. Verificou-se que as práticas de manejo utilizadas no sistema diminuíram a densidade, e interferiram na altura e distribuição diamétrica dos indivíduos em relação à vegetação da Caatinga original. Entretanto, essas práticas foram efetivas em preservar a riqueza de espécies da flora arbóreo-arbustiva, semelhantes à área de reserva vegetal nativa. Cordia oncocalyx foi a espécie com maior número de indivíduos no sistema, apresentando também maior índice de valor de importância, seguido por Mimosa caesalpiniifolia. A família Leguminosae foi a mais representativa. O índice de Shannon encontrado demonstra que o sistema agrossilvipastoril possui potencial para promover um nível intermediário de conservação, entre remanescentes de vegetação da Caatinga e áreas antropizadas neste bioma
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