36,814 research outputs found
Lovelock-Lifshitz Black Holes
In this paper, we investigate the existence of Lifshitz solutions in Lovelock
gravity, both in vacuum and in the presence of a massive vector field. We show
that the Lovelock terms can support the Lifshitz solution provided the
constants of the theory are suitably chosen. We obtain an exact black hole
solution with Lifshitz asymptotics of any scaling parameter in both
Gauss-Bonnet and in pure 3rd order Lovelock gravity. If matter is added in the
form of a massive vector field, we also show that Lifshitz solutions in
Lovelock gravity exist; these can be regarded as corrections to Einstein
gravity coupled to this form of matter. For this form of matter we numerically
obtain a broad range of charged black hole solutions with Lifshitz asymptotics,
for either sign of the cosmological constant. We find that these asymptotic
Lifshitz solutions are more sensitive to corrections induced by Lovelock
gravity than are their asymptotic AdS counterparts. We also consider the
thermodynamics of the black hole solutions and show that the temperature of
large black holes with curved horizons is proportional to where is
the critical exponent; this relationship holds for black branes of any size. As
is the case for asymptotic AdS black holes, we find that an extreme black hole
exists only for the case of horizons with negative curvature. We also find that
these Lovelock-Lifshitz black holes have no unstable phase, in contrast to the
Lovelock-AdS case. We also present a class of rotating Lovelock-Lifshitz black
holes with Ricci-flat horizons.Comment: 26 pages, 10 figures, a few references added, typo fixed and some
comments have been adde
Eficiencia comparativa dos tratamentos intra-uterinos para endometrite bovina.
bitstream/item/143037/1/2057.pd
Mosca-negra-dos-citros Aleurocanthus woglumi Ashby (Hemiptera: Aleyrodidae) em culturas de citros e de mangueira no estado de São Paulo e observações de sua biologia e controle.
Resumo: O principal objetivo deste trabalho foi avaliar a infestação da mosca-negra-dos-citros, A. woglumi, observada em janeiro de 2008, em pomar comercial de laranja PĂŞra-Rio porta enxerto de LimĂŁo-Cravo, de nove anos de idade, e em árvo- res isoladas de mangueira variedades Haden e Palmer, de sete a oito anos de idade, no municĂpio de Artur Nogueira, estado de SĂŁo Paulo. Outros objetivos foram relatar a sua biologia, os nĂveis de danos e o controle biolĂłgico dessa praga.bitstream/CNPMA/7710/1/comunicado_46.pd
Capacidade de infestação da cochonilha-do-carmim, Dactylopius ceylonicus, nas plantas hospedeiras Opuntia ficus-indica e Opuntia monacantha em condições de laboratório.
Os insetos da espĂ©cie Dactylopius ceylonicus (Green, 1896) (Hemiptera, Dactylopiidae), conhecidos mundialmente como cochonilhas-do-carmim, sĂŁo pequenos fitĂłfagos encontrados exclusivamente em cactáceas hospedeiras do gĂŞnero Opuntia. Esses insetos despertaram interesses econĂ´micos por produzirem o corante carmim que pode ser utilizado pelas indĂşstrias alimentĂcias, tĂŞxteis e de cosmĂ©ticos. Devido ao manejo incorreto de suas criações foram se tornando pragas nas plantações de cactos em todo paĂs. D. ceylonicus, se hospeda, geralmente, em cactáceas da espĂ©cie Opuntia monacantha, que sĂŁo encontradas em regiões de clima subtropical e tropical Ăşmido (várzeas de florestas e praias arenosas). O inseto Ă© utilizado, em muitos paĂses, como agente de controle biolĂłgico destas espĂ©cies de cactos. Para observar se realmente a espĂ©cie de cochonilha-do-carmim, D. ceylonicus, tem preferĂŞncia pela espĂ©cie O. monacantha, o presente trabalho comparou a capacidade de infestação da praga nesta espĂ©cie de cacto com a observada em Opuntia ficus-indica, conhecida como palma forrageira e cultivada no nordeste brasileiro como alimento para o gado nas Ă©pocas de seca. O experimento foi conduzido em condições de laboratĂłrio e consistiu em infestar simultaneamente oito plantas de cada espĂ©cie com 50 colĂ´nias de D. ceylonicus. ApĂłs 60 dias de infestação o crescimento de novas colĂ´nias mostrou a preferĂŞncia de D. ceylonicus pelos cactos da espĂ©cie O. monacantha. Análises de regressĂŁo e testes de inferĂŞncia estatĂstica foram realizadas
Pairbreaking Without Magnetic Impurities in Disordered Superconductors
We study analytically the effects of inhomogeneous pairing interactions in
short coherence length superconductors, using a spatially varying
Bogoliubov-deGennes model. Within the Born approximation, it reproduces all of
the standard Abrikosov-Gor'kov pairbreaking and gaplessness effects, even in
the absence of actual magnetic impurities. For pairing disorder on a single
site, the T-matrix gives rise to bound states within the
BCS gap. Our results are compared with recent scanning tunneling microscopy
measurements on BiSrCaCuO with Zn or Ni impurities.Comment: 4 pages, 2 figures, submitted to PR
Application of nuclear volume measurements to comprehend the cell cycle in root-knot nematode-induced giant cells.
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Previous issue date: 2017-08-1
Analytical study on holographic superconductors in external magnetic field
We investigate the holographic superconductors immersed in an external
magnetic field by using the analytical approach. We obtain the spatially
dependent condensate solutions in the presence of the magnetism and find
analytically that the upper critical magnetic field satisfies the relation
given in the Ginzburg-Landau theory. We observe analytically the reminiscent of
the Meissner effect where the magnetic field expels the condensate. Extending
to the D-dimensional Gauss-Bonnet AdS black holes, we examine the influence
given by the Gauss-Bonnet coupling on the condensation. Different from the
positive coupling, we find that the negative Gauss-Bonnet coupling enhances the
condensation when the external magnetism is not strong enough.Comment: revised version, to appear in JHE
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