Variações no teor e na composição volátil de Hyptis marrubioides EPL: cultivada no campo e em casa de vegetação

This work describes the chemical composition of the volatile oil of Hyptis marrubioides cultivated in field and greenhouse. The experimental design was completely randomized, with ten replications for each type of cultivation. The volatile oil was extracted by hydrodistillation and analyzed by GC-MS. The highest content of volatile oil was found for plants grown in field. The highest percentage of the compounds present in oils was observed in samples grown in the field, such as germacra-4(15),5,10(14)-trien-1-α-ol (16.34%), β-caryophyllene (10.42%), γ-muurolene (12.83%) and trans-thujone (9.98%). However, some compounds were found only in plants grown in a greenhouse, such as cis-muurol-5-en-4α-ol (10.84%), α-cadinol (3.06%) and eudesma-4(15),7-dien-1β-ol (6.82%).

Um "novo" velho arranjo institucional: o papel da empresa de planejamento e logística (EPL) no licenciamento ambiental das obras rodoviárias do DNIT

Pode-se afirmar que, na gestão publica brasileira, "nada se cria, tudo se transforma". Este trabalho aborda como o Ministério dos Transportes lança mão de formas de integração de organizações públicas da administração indireta de diferentes naturezas, como autarquias e empresas públicas, para o processo de licenciamento ambiental de obras rodoviárias prioritárias. Ao adotar esse "novo" arranjo o DNIT reduz os efeitos do “fator projeto” relacionados ao licenciamento ambiental. O "novo" pode ser observado no uso intensivo do Regime Diferenciado de Contratação (RDC) em processo de contratação de um ente privado por um ente privado estatal para subsidiar uma licitação de uma autarquia pública que será executada por um terceiro ente privado. Traduzindo essa relação para os atores envolvidos, a consultoria que realizará o EIA/RIMA é contratada pela EPL para subsidiar a licitação do DNIT que será executada por um concessionário.

Pitfalls driven by the sole use of local updates in dynamical

The recent claim that the exit probability (EP) of a slightly modified version of the Sznadj model is a continuous function of the initial magnetization is questioned. This result has been obtained analytically and confirmed by Monte Carlo simulations, simultaneously and independently by two different groups (EPL, 82 (2008) 18006; 18007). It stands at odds with an earlier result which yielded a step function for the EP (Europhys. Lett., 70 (2005) 705). The dispute is investigated by proving that the continuous shape of the EP is a direct outcome of a mean-field treatment for the analytical result. As such, it is most likely to be caused by finite-size effects in the simulations. The improbable alternative would be a signature of the irrelevance of fluctuations in this system. Indeed, evidence is provided in support of the stepwise shape as going beyond the mean-field level. These findings yield new insight in the physics of one-dimensional systems with respect to the validity of a true equilibrium state when using solely local update rules. The suitability and the significance to perform numerical simulations in those cases is discussed. To conclude, a great deal of caution is required when applying updates rules to describe any system especially social systems. Copyright (C) EPLA, 2011

O ensino e a investigação em Zoologia e em Botânica na Escola Politécnica de Lisboa (1837-1911)

A presente dissertação tem por objectivo o estudo do estabelecimento e da evolução das cadeiras de zoologia e de botânica da Escola Politécnica de Lisboa (EPL), desde a sua fundação, em 1837, até à reforma republicana do ensino de 1911, situando-a no meio científico da época e no contexto sociopolítico do Liberalismo português. Através de uma análise contextualista, explora-se o modo como a definição de um espaço físico próprio foi condição essencial à legitimação e à afirmação do ensino e da investigação em cada uma das áreas científicas em estudo. A criação de uma instituição de estatuto nacional, o Museu de Lisboa, foi fundamental para que a investigação científica em zoologia e em botânica encontrasse um lugar próprio na EPL e se projectasse internacionalmente, o que constituiu um passo importante para a sua consolidação no meio científico nacional. O ensino também desempenhou um papel neste processo, ao permitir a circulação de novas teorias científicas, incluindo o evolucionismo de Darwin e Haeckel e o neolamarckismo de diversos naturalistas franceses, por sucessivas gerações de alunos. A criação das cadeiras de zoologia e de botânica teve, ainda, um impacte a nível político, ao permitir que alguns dos seus professores alcançassem, através da autoridade científica adquirida nas suas áreas de especialidade, um lugar de destaque na definição de políticas dos governos liberais, quer ao nível da organização do território agrícola nacional e da modernização das práticas agrícolas existentes, quer na mobilização de esforços para a defesa de pretensões colonialistas em África. A presente dissertação mostra que a análise da institucionalização da zoologia e da botânica na EPL é fundamental para compreender a evolução do meio científico português, bem como a implementação de reformas pelos governos liberais, ao longo do século XIX.

Colossal thermoelectric power in Gd-Sr manganites

Manganites belonging to the series Gd1−xSrxMnO3 (x=0.3, 0.4 and 0.5) were prepared by wet solid-state reaction and their thermoelectric power was evaluated. Thermoelectric power measurements revealed a peak value at ∼40 K. All the samples exhibited a colossal thermopower at ∼40K and in that Gd0.5Sr0.5MnO3 exhibited a maximum value of ∼35mV/K, which is the largest reported for these class of materials at this temperature. Temperaturedependent magnetisation measurements showed that the samples exhibit a phase transition from paramagnetic to spin-glass–like state at these temperatures. Plausible mechanisms responsible for the observed colossal thermoelectric power in Gd-Sr manganites are discussed

Los efectos de la presencia paramilitar en Córdoba en las elecciones legislativas 2002-2006

El presente estudio de caso analiza el impacto de la influencia paramilitar en los resultados de las elecciones legislativas 2002 y 2006 en el Departamento de Córdoba. Busca principalmente establecer distinciones entre los diferentes casos agrupados en la noción de ‘parapolítica’. Para ello reseña el desarrollo del paramilitarismo en el Departamento y su relación con las élites políticas, posteriormente se construyó un índice de Hegemonía que indica el predominio de determinado candidato en más de la mitad de los votos de un municipio, y se analizan diversos mapas elaborados a partir de los coeficientes de Pearson y Moran. Finalmente, a partir del contraste entre el análisis estadístico y la información documental se presenta una tipología que recoge los diversos matices del apoyo paramilitar según los distintos candidatos.

El territorio la dimensión oculta en el fenómeno de desplazamiento forzado de población. Estudio de Caso en el Alto Sinú (Córdoba) 1998-2002

El desplazamiento forzado de población en la zona del Alto Sinú durante los años 1998 – 2002 responde al interés de los grupos armados ilegales por dominar el territorio y reconfigurar el orden socioeconómico en el mismo.

Desarme en procesos de paz: análisis preliminar del caso colombiano

En el presente documento se recopilan las mejores prácticas internacionales, en relación con el desarme en contextos de conflicto armado, antes de dar paso a un análisis preliminar de la experiencia de Colombia en estos procesos.

Experimental model of the interfacial instability in aluminium reduction cells

A solution has been found to the long-standing problem of experimental modelling of the interfacial instability in aluminium reduction cells. The idea is to replace the electrolyte overlaying molten aluminium with a mesh of thin rods supplying current down directly into the liquid metal layer. This eliminates electrolysis altogether and all the problems associated with it, such as high temperature, chemical aggressiveness of media, products of electrolysis, the necessity for electrolyte renewal, high power demands, etc. The result is a room temperature, versatile laboratory model which simulates Sele-type, rolling pad interfacial instability. Our new, safe laboratory model enables detailed experimental investigations to test the existing theoretical models for the first time.

Orientational behaviour of thermotropic and lyotropic liquid crystal polymer systems under shear flow

A comparison is made of the development of global orientation during shearing of lyotropic solutions of hydroxypropylcellulose with that observed for the thermotropic phase of hydroxypropylcellulose. At shear rates the behaviour of the two systems is similar, both during steady-state shear, and in terms of relaxation following cessation of shear flow. At low shear rates, the levels of orientation observed for the thermotropic system are substantially greater than observed for the lyotropic solutions. The relationship of these differences to variations in molecular parameters, viscous stress and to director tumbling is discussed.

All-or-none (or something in between) transition of DNA

DNA compaction can be caused by multivalent ions as condensing agents. Both discontinuous (all-or-none) and continuous (pearl-necklace structure) transitions have been observed in experiments as the concentration of the condensing agent was increased. We have investigated the DNA transition by analytical calculations in the infinite-chain limit. A mechanism for pearl-necklace structures could be a combinatorial entropy term, which favours a mixture of globules and coils in a single chain. However, when a surface term is taken into account, it gives rise to a discontinuous transition. We also consider the role of surface charges on the globule.

The effect of the tensor force on the predicted stability of superheavy nuclei

The effect of the tensor component of the Skyrme effective nucleon-nucleon interaction on the single-particle structure in superheavy elements is studied. A selection of the available Skyrme forces has been chosen and their predictions for the proton and neutron shell closures investigated. The inclusion of the tensor term with realistic coupling strength parameters leads to a small increase in the spin-orbit splitting between the proton 2f7/2 and 2f5/2 partners, opening the Z=114 shell gap over a wide range of nuclei. The Z=126 shell gap, predicted by these models in the absence of the tensor term, is found to be stongly dependent on neutron number with a Z=138 gap opening for large neutron numbers, having a consequent implication for the synthesis of neutron-rich superheavy elements. The predicted neutron shell structures remain largely unchanged by inclusion of the tensor component.

CMB and LSS constraints on a single-field model of inflation

A new inflationary scenario whose exponential potential V (Phi) has a quadratic dependence on the field Phi in addition to the standard linear term is confronted with the five-year observations of the Wilkinson-Microwave Anisotropy Probe and the Sloan Digital Sky Survey data. The number of e-folds (N), the ratio of tensor-to-scalar perturbations (r), the spectral scalar index of the primordial power spectrum (n(s)) and its running (dn(s)/d ln k) depend on the dimensionless parameter a multiplying the quadratic term in the potential. In the limit a. 0 all the results of the exponential potential are fully recovered. For values of alpha not equal 0, we find that the model predictions are in good agreement with the current observations of the Cosmic Microwave Background (CMB) anisotropies and Large-Scale Structure (LSS) in the Universe. Copyright (C) EPLA, 2008.

Confinement-induced phase transition in a DNA-lipid hydrated complex

We study the effect of the soft confinement by fluid lipid bilayers on the spatial organisation of DNA molecules in a DNA-zwitterionic lipid hydrated lamellar complex. The confinement is increased by dehydrating the complex in a controlled way, which leads to a decrease of the water channel thickness separating the periodically stacked bilayers. Using grazing-incidence small-angle X-ray scattering on an oriented thin film, we probe in situ as dehydration proceeds the structure of the DNA-lipid complex. A structural phase transition is evidenced, where an apparently disordered phase of DNA rods embedded within the one-dimensionally ordered lipid lamellar phase observed at high hydration is replaced by a 2D hexagonal structure of DNA molecules intercalated between the lipid bilayers. Copyright (C) EPLA, 2010