On Higher Derivatives as Constraints in Field Theory: a Geometric Perspective

We formalize geometrically the idea that the (de Donder) Hamiltonian formulation of a higher derivative Lagrangian field theory can be constructed understanding the latter as a first derivative theory subjected to constraints.Comment: 7 page

Efeito do 1,8-cineol, citral, eugenol e óleo de mamona (Ricinus communis) na reprodução de Rhipicephalus (Boophilus) microplus(Canestrini, 1888) (Acari: Ixodidae)

O desenvolvimento de resistência de Rhipicephalus (Boophilus) microplus a acaricidas comerciais vem sendo relatado desde a década de 40. Sendo assim, trabalhos de pesquisas com óleos essenciais e fixos têm sido desenvolvidos visando encontrar alternativas ao controle químico desta espécie de carrapato. O objetivo do trabalho foi avaliar o efeito de formulações contendo 1,8-cineol, citral, eugenol e óleo de mamona (Ricinus communis) sobre a reprodução de R. (B.) microplus. Grupos contendo 10 parasitas foram tratados com emulsões desses óleos em DMSO associado a Tween 80® ou éter lauril sulfato. A eficácia carrapaticida foi avaliada pelo teste de imersão de fêmeas. Para a análise dos efeitos teciduais, as fêmeas tiveram os ovários dissecados, fixados e submetidos à rotina histológica. O 1,8-cineol, citral e eugenol 1% (m/v) e óleo de mamona em 0,3% (m/v) apresentaram valores de eficácia de 29%; 11,6% e 9,8%, respectivamente. O efeito dos solubilizantes (DMSO associado com Tween 80® ou éter lauril sulfato) foi avaliado para o 1,8-cineol (10% (m/v)) e óleo de mamona em 0,3% (m/v), de forma isolada e associada. Os valores de eficácia observados para o 1,8-cineol isolado (92,8%) e associado ao óleo de mamona (94,1%) foram superiores quando as emulsões foram preparadas utilizando o éter lauril sulfato como solubilizante. Alterações morfológicas nos ovócitos em diferentes estágios de desenvolvimento (I-V), bem como nas células do pedicelo, foram observadas tanto nas fêmeas tratadas com óleo de mamona (0,3% (m/v)) como naquelas com 1,8-cineol (10% (m/v)), sendo verificados efeitos mais intensos quando ambos estavam em associação. A formulação de 1,8-cineol (10% (m/v)) associada ao óleo de mamona (0,3% (m/v)) em éter lauril sulfato (2% (m/v)) demonstrou-se promissora no controle reprodutivo de R. (B.) microplus. Espera-se que os resultados obtidos possam nortear projetos futuros, em consonância com o bem-estar animal, visando o desenvolvimento de alternativas ao controle de carrapatos com produtos comerciais

Finding critical points using improved scaling Ansaetze

Analyzing in detail the first corrections to the scaling hypothesis, we develop accelerated methods for the determination of critical points from finite size data. The output of these procedures are sequences of pseudo-critical points which rapidly converge towards the true critical points. In fact more rapidly than previously existing methods like the Phenomenological Renormalization Group approach. Our methods are valid in any spatial dimensionality and both for quantum or classical statistical systems. Having at disposal fast converging sequences, allows to draw conclusions on the basis of shorter system sizes, and can be extremely important in particularly hard cases like two-dimensional quantum systems with frustrations or when the sign problem occurs. We test the effectiveness of our methods both analytically on the basis of the one-dimensional XY model, and numerically at phase transitions occurring in non integrable spin models. In particular, we show how a new Homogeneity Condition Method is able to locate the onset of the Berezinskii-Kosterlitz-Thouless transition making only use of ground-state quantities on relatively small systems.Comment: 16 pages, 4 figures. New version including more general Ansaetze basically applicable to all case

Irrigação por bacias em nível na cultura da bananeira.

Descrição do sistema de irrigação; Vantagens, desvantagens e adaptabilidade; Bases para o dimensionamento; Operação e manejo do sistema de irrigação; Considerações sobre a exploração comercial da bananeira irrigada por bacias em nível.bitstream/item/71927/1/CPAMN-CIR.-TEC.-04-92.pd

Core and Periphery in the European Monetary Union: Bayoumi and Eichengreen 25 Years Later

Bayoumi-Eichengreen (1993) establish a EMU core-periphery pattern using 1963-1988 data. We use same methodology, sample, window length (1989-2015), and a novel over-identifying restriction test to ask whether the EMU strengthened or weakened the core-periphery pattern. Our results suggest the latter

The United Kingdom and the Stability of the Euro Area: From Maastricht to Brexit

© 2020 The Authors. The two key events expected to mark the year 2019 were the 20th anniversary of the euro and Brexit. This paper examines the role of the United Kingdom on the stability of the euro area. We study stability from the perspective of synchronisation of economic activity in a core and periphery framework. We show the UK, since 1990, has become significantly more integrated with the EU economy. The UK moved from the periphery before 1990 to the core afterwards. We also find that the level of synchronisation of the UK economy has had the highest variability over time among all countries

Symmetry and Convergence in Monetary Unions

This paper has three main objectives, namely to (a) propose a new framework that can support placing countries along a core-periphery continuum (beyond the more common binary treatment as either core or periphery), (b) to construct a continuous dynamic theory-based measure (the first, to the best of our knowledge) illustrating the use of this framework for a set of European countries using yearly data from 1960 to 2015, and (c) provide a first preliminary assessment, based on endogenous Optimal Currency Area (OCA) theory, of the main potential explanatory factors of the dynamics of this measure over time and across countries. Our main finding is that this new measure allows us to identify sets of countries on the basis of not only its level but also in terms of its dynamic behaviour. Using the Phillips-Sul procedure, we show the emergence a newer set of core countries (composed by Austria, Belgium, Germany, France, Italy and Netherlands), a mixed set of countries (namely Denmark, Sweden, Greece, Spain and the UK), and a set of deep-rooted periphery countries (Finland, Ireland, Norway, Portugal, and Switzerland). There are valuable lessons from the dynamics of this measure. It increases for core countries (which confirms endogenous OCA predictions), remains worrisomely constant for a periphery, and varies substantially for the intermediate set of countries. Spain (Sweden and Greece) becomes consistently more (less) core over time, Denmark’s remains constant and the UK moves in and out of the core over time. Our panel estimates on a specification suggested by endogenous OCA theory imply that euro membership and more flexible product market regulations (or trade openness) make countries more likely to be in the core