14,639 research outputs found
Magnetoresistive Effects in Ferromagnet-Superconductor Multilayers
We consider a nanoscale system consisting of Manganite-ferromagnet and
Cuprate-superconductor multilayers in a spin valve configuration. The
magnetization of the bottom Manganite-ferromagnet is pinned by a
Manganite-antiferromagnet. The magnetization of the top Manganite-ferromagnet
is coupled to the bottom one via indirect exchange through the superconducting
layers. We study the behavior of the critical temperature and the
magnetoresistance as a function of an externally applied parallel magnetic
field, when the number of Cuprate-superconductor layers are changed. There are
two typical behaviors in the case of a few monolayers of the Cuprates: a) For
small magnetic fields, the critical temperature and the magnetoresistance
change abruptly when the flipping field of the top Manganite-ferromagnet is
reached. b) For large magnetic fields, the multilayered system re-enters the
zero-resistance (superconducting) state after having become resistive (normal).Comment: 3 pages, 3 figures. 2004 Magnetism and Magnetic Materials Conferenc
Gestão ambiental do agronegócio hortifrutÃcola.
O conceito de sustentabilidade resgata a necessidade de um balanço entre fatores sociais, ambientais e econômicos.1 CD-ROM. Palestra
Immature embryo rescue and in vitro development evaluation of intraspecific hybrids from Brazilian seedless grapevine Superior × Thompson clones.
The fruit production for export is an economically significant activity in the Valley of São Francisco River, especially in the irrigated lands of Petrolina-PE/Juazeiro-BA, Brazil. The development of new genetic material most suitable to the tropical climate and the demands of the consumer market have led to the selection of new seedless grapes cultivars. In this case, the use of the embryo rescue technique has produced satisfactory results for obtaining such materials, especially in the semiarid region. This study aimed to evaluate the in vitro development of intraspecific hybrids of grapevine (Vitis vinifera L.), derived from the rescue of immature embryos resultant from the crossing of Superior Seedless and Thompson Seedless Brazilian clones. To establish and develop the cultivation, the culture media was supplemented with 30 g/L sucrose, 0.1 g/L myo-inositol, 0.002 g/L glycine, 0.1 mg/L indoleacetic acid (IAA), 6.5 g/L of agar, adjusted pH to 5.7. The experiment was evaluated after 90 days. The variables measured were: number of nodes, number of leaves, plant height (cm), number of roots and length (cm) of the root system and internodes. The period of 60 days of in vitro culture of ovules resulted in the highest values of embryos (about 50%), as well as better characterized developmental stages with higher germination (47.3%). The three types of hybrid grapes evaluated in micropropagation showed very similar values of the measured parameters, even having originated from embryos of different developmental stages
Two-species fermion mixtures with population imbalance
We analyze the phase diagram of uniform superfluidity for two-species fermion
mixtures from the Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensation
(BEC) limit as a function of the scattering parameter and population imbalance.
We find at zero temperature that the phase diagram of population imbalance
versus scattering parameter is asymmetric for unequal masses, having a larger
stability region for uniform superfluidity when the lighter fermions are in
excess. In addition, we find topological quantum phase transitions associated
with the disappearance or appearance of momentum space regions of zero
quasiparticle energies. Lastly, near the critical temperature, we derive the
Ginzburg-Landau equation, and show that it describes a dilute mixture of
composite bosons and unpaired fermions in the BEC limit.Comment: 4 pages with 3 figures, accepted version to PR
Insights into the quark-gluon vertex from lattice QCD and meson spectroscopy
By comparing successful quark-gluon vertex interaction models with the
corresponding interaction extracted from lattice-QCD data on the quark's
propagator, we identify common qualitative features which could be important to
tune future interaction models beyond the rainbow ladder approximation.
Clearly, a quantitative comparison is conceptually not simple, but
qualitatively the results suggest that a realistic interaction should be
relatively broad with a strong support at about ~GeV and
infrared-finite
Topological phase transitions in ultra-cold Fermi superfluids: the evolution from BCS to BEC under artificial spin-orbit fields
We discuss topological phase transitions in ultra-cold Fermi superfluids
induced by interactions and artificial spin orbit fields. We construct the
phase diagram for population imbalanced systems at zero and finite
temperatures, and analyze spectroscopic and thermodynamic properties to
characterize various phase transitions. For balanced systems, the evolution
from BCS to BEC superfluids in the presence of spin-orbit effects is only a
crossover as the system remains fully gapped, even though a triplet component
of the order parameter emerges. However, for imbalanced populations, spin-orbit
fields induce a triplet component in the order parameter that produces nodes in
the quasiparticle excitation spectrum leading to bulk topological phase
transitions of the Lifshitz type. Additionally a fully gapped phase exists,
where a crossover from indirect to direct gap occurs, but a topological
transition to a gapped phase possessing Majorana fermions edge states does not
occur.Comment: With no change in text, the labels in the figures are modifie
Instruções para o cultivo do maracujá em Sergipe.
Botânica, clima e solo, produção de mudas, preparo do solo e plantio, condução e poda , adubação e tratos culturais, polinização artificial, pragas, doençaas, colheita e rendimento.bitstream/item/44457/1/CPATC-DOCUMENTOS-5-INSTRUCOES-PARA-O-CULTIVO-DO-MARACUJA-EM-SERGIPE-FL-13123A.pd
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