Resumo Em todo o mundo, a agricultura convencional faz uso extensivo de pesticidas. Embora os efeitos dos herbicidas sejam relativamente bem conhecidos em termos de impactos ambientais em organismos não-alvo, há pouca evidência científica sobre os impactos de resíduos de herbicidas em artrópodes aquáticos de áreas de conservação tropicais. Este estudo avalia pela primeira vez a toxicidade dos herbicidas ametryn, atrazine e clomazone sobre o inseto aquático Limnocoris submontandoni (Hemiptera: Naucoridae). A concentração letal (LC50) de herbicidas foi avaliada para esses insetos, bem como o efeito dos herbicidas nos tecidos e testículos dos insetos. A LC50 estimada foi de 1012,41, 192,42 e 46,09 mg/L para clomazone, atrazine e ametryn, respectivamente. Alterações nos espermatócitos e espermátides foram observadas sob o efeito de atrazine, e efeitos na espermatogênese foram observados para algumas concentrações de clomazone, com aparente recuperação após um curto período de tempo. Nossos resultados fornecem informações úteis sobre os efeitos de resíduos de herbicidas em sistemas aquáticos. Essas informações podem ajudar a minimizar o risco de efeitos reprodutivos de longo prazo em espécies não-alvo que foram negligenciadas anteriormente em estudos de ecotoxicologia.

Abstract Worldwide, conventional agriculture makes extensive use of pesticides. Although the effects of herbicides are relatively well known in terms of environmental impacts on non-target organisms, there is very little scientific evidence regarding the impacts of herbicide residues on aquatic arthropods from tropical conservation areas. This study evaluates for the first time the toxicity of the herbicides ametryn, atrazine, and clomazone on the aquatic insect Limnocoris submontandoni (Hemiptera: Naucoridae). The lethal concentration (LC50) of herbicides was evaluated for these insects, as well as the effect of the herbicides on the insects’ tissues and testicles. The estimated LC50 was 1012.41, 192.42, and 46.09 mg/L for clomazone, atrazine, and ametryn, respectively. Spermatocyte and spermatid changes were observed under the effect of atrazine, and effects on spermatogenesis were observed for some concentrations of clomazone, with apparent recovery after a short time. Our results provide useful information on the effects of herbicide residues in aquatic systems. This information can help minimize the risk of long-term reproductive effects in non-target species that have been previously overlooked in ecotoxicology studies.

The Planck's radiation law for the black body radiation spectrum was capable to explain the experimentally-measured black body spectrum. In order to get this result, Planck proposed his radiation law in a two-fold way: 1) by an ad hoc modification of the assumed connection between energy and entropy for thermal radiation; 2) by assuming that the calculation of the entropy of an oscillator in thermal equilibrium with radiation is carried out by discrete units of energy. As a consequence, the energy quantization, linear in frequency, was thus introduced into physics. However, the energy quantization of the simple harmonic oscillator was originally postulated by Planck in an incomplete way, i.e., the ground state energy was assumed to be null. Of course, this issue has been solved in different ways over time, even by him. Despite this, we propose an alternative way to restore the non-null ground state energy of the harmonic oscillators at noncommutative(NC) framework, where, how will be shown, the non-null ground state energy naturally arises as a NC contribution. With this approach, the Planck's quantum theory is updated and, consequently, becomes compatible with the Quantum Mechanics inaugurated in 1925.

As long we known, the non-relativistic Lagrangian definition, L = T − U with T and U as being, respectively, kinetic and potential energy, it is not valid at the relativistic level. This issue partially obstructs the college student’s comprehension of special theory of relativity from the Lagrangian formalism. Further, it is well known that the space-time world demands essentials principles of special theory of relativity: four-vectors and Lorentz invariance. In this work, we departure from these basics concepts of space-time world in order to get a relativistic Lagrangian definition parallel to the non-relativistic one and, as a consequence, this can help the college student to better understand special theory of relativity [1].

It is well known that hypothetical tunnels net within the Earth is usually considered as an illustration in a gravitation course for undergraduate students. In this context, an uniform mass distribution is usually considered and, consequently, a vehicle inside the tunnel oscillates in a simple harmonic motion (SHM). In this work, we investigate this problem and we argue that, instead to illustrate this problem using Earth, it is better to consider the Moon. In order to support this proposition, we present a twofold argumentation: first, we show that there is a quite discrepancy between the results obtained from Earth uniform mass distribution model with those obtained considering realistic Earth models (PREM model), whose mass is nonuniformly distributed; second, when the Moon is considered, we show that there is not a discrepancy between the results computed from uniform mass distribution model with those computed from nonuniform mass distribution. Indeed, we revealed that a vehicle inside the tunnel within Moon oscillates approximately in a SHM.

Abstract In this paper the magnetic geared machines electromagnetic concepts are introduced. The magnetic gear modulation mechanism which becomes possible rotors of different polarities produce torque is explained, through the use analytical expressions and plots obtained by finite elements method. This pedagogical approach is a way to teach the subject in a more understandable way and, at the same time, it reinforces the application of electromagnetic concepts. Further, a magnetic geared generator is simulated and no-load EMFs and torques are analyzed.

A Bacia Hidrográfica da Lagoa das Sete Cidades localiza-se no maciço com o mesmo nome, na região Nordeste da Ilha de São Miguel. Possui uma área de 445,5 ha e é constituída por duas sub-unidades, a Lagoa Azul (357,3 ha) e a Lagoa Verde (88,2 ha). A maior parte da bacia hidrográfica é ocupada principalmente por pasta-gens permanentes. Devido a problemas ligados ao uso agrícola desta bacia (carga animal e uso excessivo de adubo) a sua situação trófica tem vindo gradualmente a deteriorar-se. O índice de P (Lemunyon & Gilbert, 1993) foi criado para identificar especificamente as áreas onde é maior o risco de perda de fósforo do solo para as águas superficiais numa bacia hidrográfica. A sua aplicação permite referenciar no terreno as fontes difusas de poluição, uma vez que se baseia na avaliação por parcela dos factores (de origem e de transporte) considerados relevantes para a mobilização de nutrientes para a massa de água. Neste trabalho foram considerados como factores de origem os valores de P Olsen e as quantidades de adubo aplicadas (kg P2O5 ha-1 ano-1) e como factores de transporte o potencial de escoamento (estimado a partir do declive), distância da parcela à linha de água e distância da parcela à massa de água (m). Com a adopção desta metodologia pretendeu-se identificar possíveis áreas de risco de perda de P e assim contribuir para o desenvolvimento de programas e/ou de planos de gestão adequados à bacia hidrográfica das Sete Cidades.

The Sete Cidades catchment is located in the geological site with the same name, in the Northeast of the São Miguel Island. It has an 444,5 ha area and is formed by two sub units, the Blue Lagoon (357,3 ha) and the Green Lagoon (88,2 ha). The most part of the watershed is occupied by permanent pastures. Due to agriculture land use (animal pressure and excessive fertilization), its trophic condition is increasingly deteriorating. The P index was created by Lemunyon & Gilbert (1993) to identify the areas which most contributes to phosphorus losses from soil to the water bodies. Its application helps locating diffuse polluting sources, since it is based on the evaluation on a parcel basis of source and transports factors considered as relevant to the nutrient mobilization to the water mass. In this study are considered as source factors the P Olsen and applied fertilizer (kg P2O5 ha-1 year-1), and as transport factors the leaching potential (as estimated from slope), distance from field to the water line and from field to the water body (m). With this methodology we intended to identify the risk of P loss areas and thus contribute to the development of programs and/or management plans addressed to the Sete Cidades watershed.

Estudos sobre monitoramento, regeneração florestal e manejo de fauna devem usar a história ambiental como referência para compreender o passado da área de estudo e para monitorar os resultados desses estudos. Para criar a base da história ambiental para o Parque Nacional da Tijuca, relatamos duas iniciativas clássicas de restauração e a lista das espécies de mamíferos que ocorrem atualmente neste parque urbano, que depende dessas iniciativas. O Parque Nacional da Tijuca (PNT) é um parque urbano de 3.200 ha coberto por floresta tropical secundária e cercado pela cidade do Rio de Janeiro, no Sudeste do Brasil. No PNT, ocorreram duas iniciativas clássicas de restauração: a pioneira restauração da floresta tropical no século XIX e o projeto de manejo da fauna nos anos 70. A lista de mamíferos foi baseada em publicações e nos espécimens depositados no Museu Nacional do Rio de Janeiro. A comunidade de mamíferos do PNT é composta por 49 espécies, sendo 11 incluídas nas listas vermelhas regionais e quatro espécies na Lista Vermelha de Espécies Ameaçadas da IUCN de 2003. A ocorrência dessas espécies ameaçadas e a história do parque tornaram o Parque Nacional da Tijuca uma área de estudo prioritária para monitoramento, conservação e manejo. Além do PNT ser um parque urbano importante para a manutenção da diversidade da fauna e da flora, incluindo as espécies ameaçadas, também melhora a qualidade de vida da população da cidade do Rio de Janeiro, fornecendo áreas verdes, recreação, turismo e abastecimento de água. Concluindo, enfatizamos a grande importância da história ambiental no Parque Nacional da Tijuca para a composição atual da comunidade de mamíferos.

As a contribution to the environmental history of the Tijuca National Park, we report on two pioneering restorationist initiatives and list its the mammal species now found in this urban park. The Tijuca National Park (TNP), a 3,200 ha urban park covered by secondary tropical forest, is located within Rio de Janeiro, in southeastern Brazil. The two restorationist initiatives were a pioneer tropical forest restoration project in the nineteenth century and a fauna management project in the 70' s. The mammal list presented here was based on specimens in the Museu Nacional do Rio de Janeiro and on publications. The mammal community of TNP is composed of 49 species, of which 11 are on regional red lists, and four are on the 2003 IUCN Red List of Threatened Species. Occurrence of these threatened species and the park history itself made the TNP a priority site for studying conservation, management, and monitoring. Besides maintaining fauna and flora (including threatened species) diversity, the park benefits the population of Rio de Janeiro by providing water, green areas, and recreational and touristic opportunities.

Neste estudo descrevemos a ultra-estrutura das células enteroendócrinas observadas no intestino médio de M. quadrifasciata anthidioides, abelha na qual ocorrem dois tipos de células enteroendócrinas, concentradas na região posterior do intestino médio. As células do tipo fechado são menores e possuem grânulos de secreção menos eletrodensos e menos regulares do que as células do tipo aberto. As células do tipo aberto possuem ainda longas mitocôndrias concentradas principalmente na região basal, onde também se concentra a maior parte dos grânulos de secreção. Além dos grânulos de secreção e das mitocôndrias, as células endócrinas nessa espécie possuem grandes vacúolos autofágicos e elementos do complexo de Golgi bem desenvolvidos.

In this study we describe the ultrastructure of the endocrine cells observed in the midgut of M. quadrifasciata anthidioides. This bee has two types of endocrine cells, which are numerous on the posterior midgut region. Cells of the closed type are smaller and have irregular secretory granules with lower electrondensity than those of the open cell type. The open cell type has elongated mitochondria mainly on the basal area, where most of the secretory granules are also found. Besides the secretion granules and mitochondria, endocrine cells in this species have well-developed autophagic vacuoles and Golgi complex elements.

In this paper, the analog of Maxwell electromagnetism for hydrodynamic turbulence, the metafluid dynamics, is extended in order to reformulate the metafluid dynamics as a gauge field theory. That analogy opens up the possibility to investigate this theory as a constrained system. Having this possibility in mind, we propose a Lagrangian to describe this new theory of turbulence and, subsequently, analyze it from the symplectic point of view. From this analysis, a hidden gauge symmetry is revealed, providing a clear interpretation and meaning of the physics behind the metafluid theory. Also, the geometrical interpretation to the gauge symmetries is discussed.

For several years it was believed that angiotensin II (Ang II) alone mediated the effects of the renin-angiotensin system. However, it has been observed that other peptides of this system, such as angiotensin-(1-7) (Ang-(1-7)), present biological activity. The effect of Ang II and Ang-(1-7) on renal sodium excretion has been associated, at least in part, with modulation of proximal tubule sodium reabsorption. In the present review, we discuss the evidence for the involvement of Na+-ATPase, called the second sodium pump, as a target for the actions of these compounds in the regulation of proximal tubule sodium reabsorption.

Uma nova abordagem para adoção do método do Perfil Cultural em condições de solos tropicais é aqui tratada. Analisou-se a evolução desse método desde seu início na França, na década de 1960, até a proposta de sua utilização no estudo de manejo de solos tropicais. Tal método mostra-se eficiente no diagnóstico qualitativo do estado físico dos solos no campo, na orientação de amostragem de solos, no estudo dos efeitos da antropização, na visualização das interações físicas, químicas e biológicas dos solos, nos estudos de mecânica do solo no campo e no estudo da organização estrutural de solos agrícolas, além de auxiliar na análise do sistema radicular.

A new approach is discussed for adoption of criteria in the application of the cultural profile methodology for tropical soil conditions. The evolution of this methodology has been analyzed since its beginning in France in the 1960s, until its proposal for tropical soil management studies. The cultural profile approach can be used to make qualitative diagnosis of the physical state of soil in the field, as well as to help with soil sampling, to study the effect of agricultural machinery, to visualize the physical, chemical and biological soil interactions, and to help with the studies of contraction, expansion, and shearing in the field and in the structural organization of soils and root system analyses.