The Periodic Standing-Wave Approximation: Overview and Three Dimensional Scalar Models

The periodic standing-wave method for binary inspiral computes the exact numerical solution for periodic binary motion with standing gravitational waves, and uses it as an approximation to slow binary inspiral with outgoing waves. Important features of this method presented here are: (i) the mathematical nature of the ``mixed'' partial differential equations to be solved, (ii) the meaning of standing waves in the method, (iii) computational difficulties, and (iv) the ``effective linearity'' that ultimately justifies the approximation. The method is applied to three dimensional nonlinear scalar model problems, and the numerical results are used to demonstrate extraction of the outgoing solution from the standing-wave solution, and the role of effective linearity.Comment: 13 pages RevTeX, 5 figures. New version. A revised form of the nonlinearity produces better result

Transição agroecológica em sistema de produção familiar: a experiência da Família Zeferino em Brasil Novo, Pará.

Este trabalho tem como objetivo relatar a experiência de transição agroecológica vivenciada pela família Zeferino no município do Brasil Novo no Estado do Pará, caracterizando os princípios agroecológicos utilizados nos sistemas de produção e a história de vida da família. A família Zeferino composta pela Sra. Dercília e o Sr. José, conhecido como ?Cido?, e dois filhos foram pioneiros e inovadores no desenvolvimento de experiências agroecológica na região da Transamazônica, no entanto faleceram precocemente em 2014 e 2016 respectivamente. As atividades desenvolvidas pela família tinha como base a produção orgânica em sistema agroflorestais. Além de desenvolver experiências de produção sustentáveis, a família compartilhava o seu ?saber agroecológico?, com todos os segmentos da sociedade, sendo considerados como Referência no respeito no uso dos recursos naturais de nossa região.Edição dos anais do VI Congresso Latino-Americano (CLAA), X Congresso Brasileiro (CBA), V Seminário do DF e Entorno (SEMDF), 12-15 setembro de 2017, a Brasília, DF, Brasil

Shell sources as a probe of relativistic effects in neutron star models

A perturbing shell is introduced as a device for studying the excitation of fluid motions in relativistic stellar models. We show that this approach allows a reasonably clean separation of radiation from the shell and from fluid motions in the star, and provides broad flexibility in the location and timescale of perturbations driving the fluid motions. With this model we compare the relativistic and Newtonian results for the generation of even parity gravitational waves from constant density models. Our results suggest that relativistic effects will not be important in computations of the gravitational emission except possibly in the case of excitation of the neutron star on very short time scales.Comment: 16 pages LaTeX with 6 eps figures; submitted to Phys. Rev.

Head-on collision of unequal mass black holes: close-limit predictions

The close-limit method has given approximations in excellent agreement with those of numerical relativity for collisions of equal mass black holes. We consider here colliding holes with unequal mass, for which numerical relativity results are not available. We try to ask two questions: (i) Can we get approximate answers to astrophysical questions (ideal mass ratio for energy production, maximum recoil velocity, etc.), and (ii) can we better understand the limitations of approximation methods. There is some success in answering the first type of question, but more with the second, especially in connection with the issue of measures of the intrinsic mass of the colliding holes, and of the range of validity of the method.Comment: 19 pages, RevTeX + 9 postscript figure

Trapped and excited w modes of stars with a phase transition and R>=5M

The trapped $w$-modes of stars with a first order phase transition (a density discontinuity) are computed and the excitation of some of the modes of these stars by a perturbing shell is investigated. Attention is restricted to odd parity (``axial'') $w$-modes. With $R$ the radius of the star, $M$ its mass, $R_{i}$ the radius of the inner core and $M_{i}$ the mass of such core, it is shown that stars with $R/M\geq 5$ can have several trapped $w$-modes, as long as $R_{i}/M_{i}<2.6$. Excitation of the least damped $w$-mode is confirmed for a few models. All of these stars can only exist however, for values of the ratio between the densities of the two phases, greater than $\sim 46$. We also show that stars with a phase transition and a given value of $R/M$ can have far more trapped modes than a homogeneous single density star with the same value of $R/M$, provided both $R/M$ and $R_{i}/M_{i}$ are smaller than 3. If the phase transition is very fast, most of the stars with trapped modes are unstable to radial oscillations. We compute the time of instability, and find it to be comparable to the damping of the $w$-mode excited in most cases where $w$-mode excitation is likely. If on the other hand the phase transition is slow, all the stars are stable to radial oscillations.Comment: To appear in Physical Review

Levantamento da ocorrência de populações do nematoide-das-galhas-do-cafeeiro (Meloidogyne sp.) em Rondônia: primeira atualização.

Objetivou-se neste trabalho determinar a ocorrência das principais espécies Meloidogyne em lavouras de café rondonienses por meio da caracterização das mesmas, a partir de análises morfológicas e isoenzimáticas de fêmeas do nematoide, coletadas de raízes e solo.bitstream/item/141377/1/COT-397-Levantamento-da-ocorrencia-de-populacoes-do-nematoides-das-galhas-do-cafeeiro-Meloidogyne-sp.-em-Rondonia-primeira-atualizacao.pd

Rhizoctoniose x fusariose x roseliniose do cafeeiro: saiba diferenciar para melhor manejar.

Neste trabalho, pretende-se demonstrar de forma prática maneiras de diferenciar a ocorrência desses patógenos e, consequentemente, auxiliar produtores e extensionistas a manejar adequadamente as lavouras para evitar ou minimizar os danos provocados por estes patógenos.bitstream/item/216349/1/cpafro-18444-cot-402.pd

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]