Conchostráceos com linhas de crescimento recurvadas junto à margem dorsal (Famílias Palaeolimnadiopseidae e Perilimnadiidae) da Formação Rio do Rasto, permiano superior, Bacia do Paraná, Brasil

Some Upper Permian conchostracans from the Rio do Rasto Formation (Paraná Basin, South Brazil) have very characteristic recurved growth lines at the dorsal margin. All previously described specimens were classified as Palaeolimnadiopsis subalata (Reed) Raymond. However, a re-analysis of these fossils and of additional recently- collected specimens demonstrated that not all can be included in a single species, nor only in the Family Palaeolimnadiopseidae. According to their shape and the size of the umbo, they are classified into three species. The sub-elliptic carapaces with small anterior umbo are maintained in Palaeolimnadiopsis subalata (Reed, 1929) Raymond, 1946. The sub-circular carapaces with small sub-central umbo correspond to the new species Palaeolimnadiopsis riorastensis. The small size of the umbo is a character of the Family Palaeolimnadiopseidae. The small elliptic valves with large anterior umbo are assigned to the new species Falsisca brasiliensis of the Family Perilimnadiidae, which is characterized by large umbos. Palaeolimnadiopsis has a wide chronostratigraphic distribution, but Falsisca is restricted to the Upper Permian-Lower Triassic of Europe and Asia. This interval is in agreement with the probable Late Permian age of the respective strata of the Rio do Rasto Formation. Falsisca was not previously recorded in Gondwana.

Ultra-high energy extragalactic neutrinos interacting with ultra-light dark matter

We show the results and discussions of the study of a possible suppression of the extragalactic neutrino flux during its propagation due to a nonstandard interaction with a candidate field to dark matter. In particular, we show the study of neutrino interaction with an ultra-light scalar field. It is shown that the extragalactic neutrino flux may be suppressed by such an interaction, leading to a mechanism to reduce the ultra-high energy neutrino flux. We calculate both the cases of non-self-conjugate as well as self-conjugate ultra-light dark matter. In the first case, the suppression is independent of the neutrino and dark matter masses. We conclude that care must be taken when explaining limits on the neutrino flux through source acceleration mechanisms only, since there could be other mechanisms, as absorption during propagation, for the reduction of the neutrino flux [1], © Published under licence by IOP Publishing Ltd.

Optimal low-cost transfer to L4 and L5 lagrangian points based on G-family of periodic orbits

An alternative transfer strategy to send spacecrafts to stable orbits around the Lagrangian equilibrium points L4 and L5 based in trajectories derived from the periodic orbits around LI is presented in this work. The trajectories derived, called Trajectories G, are described and studied in terms of the initial generation requirements and their energy variations relative to the Earth through the passage by the lunar sphere of influence. Missions for insertion of spacecrafts in elliptic orbits around L4 and L5 are analysed considering the Restricted Three-Body Problem Earth- Moon-particle and the results are discussed starting from the thrust, time of flight and energy variation relative to the Earth. Copyright© (2012) by the International Astronautical Federation.

Scaling invariance of the diffusion coefficient in a family of two-dimensional Hamiltonian mappings

We consider a family of two-dimensional nonlinear area-preserving mappings that generalize the Chirikov standard map and model a variety of periodically forced systems. The action variable diffuses in increments whose phase is controlled by a negative power of the action and hence effectively uncorrelated for small actions, leading to a chaotic sea in phase space. For larger values of the action the phase space is mixed and contains a family of elliptic islands centered on periodic orbits and invariant Kolmogorov-Arnold-Moser (KAM) curves. The transport of particles along the phase space is considered by starting an ensemble of particles with a very low action and letting them evolve in the phase until they reach a certain height h. For chaotic orbits below the periodic islands, the survival probability for the particles to reach h is characterized by an exponential function, well modeled by the solution of the diffusion equation. On the other hand, when h reaches the position of periodic islands, the diffusion slows markedly. We show that the diffusion coefficient is scaling invariant with respect to the control parameter of the mapping when h reaches the position of the lowest KAM island. © 2013 American Physical Society.

Satelites estabilizados por rotação e torque magnético residual

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise de métodos numéricos de diferenças finitas para solução da equação de Poisson em domínios irregulares

Pós-graduação em Matematica Aplicada e Computacional - FCT

Criptografia e curvas elípticas

Pós-graduação em Matemática Universitária - IGCE

Transformações de Möbius e inversões

Pós-graduação em Matemática Universitária - IGCE

Simulação numérica de escoamentos de fluídos pelo método de elementos finitos baseado em volumes de controle com a técnica de passo fracionado

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Proposta e modelagem de comunicação segura para redes veiculares (VANETS)

Pós-graduação em Ciência da Computação - IBILCE

Morfoanatomia do pericarpo, semente, folha de Psychotria hoffmannseggiana (Willd. ex Roem. & Schult.) Müll. Arg. e Psychotria trichophora Müll. Arg., e desenvolvimento morfológico da plântula de Psychotria hoffmannseggiana (Willd. ex Roem. & Schult.) Müll. Arg. (Rubiaceae, Rubioideae, Psychotrieae)

Pós-graduação em Ciências Biológicas (Biologia Vegetal) - IBRC

Anatomia e desenvolvimento pós-seminal de espécies de Bromeliaceae (Poales) da Amazônia - MT

Pós-graduação em Ciências Biológicas (Biologia Vegetal) - IBRC

Evolução do magmatismodo domínio cachoeirinha: suítes intrusivas Santa Cruz, Alvorada, Rio Branco e Salto do Céu-SW do cráton amazônico - MT

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Morfo-anatomia e desenvolvimento pós-seminal de cinco espécies de Bromeliaceae

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Problemas elípticos com potencial que pode tender a zero no in?nito

Pós-graduação em Matemática - IBILCE