Point-source scalar turbulence

The statistics of a passive scalar randomly emitted from a point source is investigated analytically. Our attention has been focused on the two-point equal-time scalar correlation function. The latter is indeed easily related to the spectrum, a statistical indicator widely used both in experiments and in numerical simulations. The only source of inhomogeneity/anisotropy is in the injection mechanism, the advecting velocity here being statistically homogeneous and isotropic. Our main results can be summarized as follows. 1) For a very large velocity integral scale, a pure scaling behaviour in the distance between the two points emerges only if their separation is much smaller than their distance from the point source. 2) The value we have found for the scaling exponent suggests the existence of a direct cascade, in spite of the fact that here the forcing integral scale is formally set to zero. 3) The combined effect of a finite inertial-range extension and of inhomogeneities causes the emergence of subleading anisotropic corrections to the leading isotropic term, that we have quantified and discussed.Comment: 10 pages, 1 figure, submitted to Journal of Fluid Mechanic

A stochastic spreadsheet model analysing investment options for the development of pasture on beef cattle farms : a dissertation submitted in partial fulfilment of the requirements for the degree of Master in Applied Science at Massey University

The decision to proceed with farm development to increase animal production is complex. Standalone personal computer software to study either the financial or physical aspects of farm development is available, but models which integrate these components and account for the risks associated with the investment are not. A stochastic spreadsheet (Microsoft Excel®) model was therefore developed to predict the profitability, feasibility and risk of pasture development for two case farms: one in southern Brazil and the other near Wanganui in New Zealand. Pasture was developed at different rates for each farm and the model was used to predict the associated physical and financial changes over-time and a probability distribution of the net present values (NPV) of the net operating profit after tax and before interest (NOPAT) relative to the status quo situation. The extra pasture was used solely for increasing beef cattle production. On the Brazilian case farm the development of 2,263 ha at two rates was studied. The continuation of the status quo had first degree stochastic dominance in terms of the NPV over both development rates; it was superior by about NZ$46.000 for the 200 ha/y option and ca. NZ$ 110.000 for the 500 ha/y option at a 16% discount rate. However, at a 6% discount rate the 500 ha/y development rate had first degree stochastic dominance in terms of the NPV over both the continuation of the status quo (by about NZ$960.000) and the 200 ha/y option (ca. NZ$ 120.000). This indicates that pasture development could proceed profitability if interest rates continue to fall in Brazil as predicted. For the New Zealand case farm the development of 247 ha at 50 ha/y had first degree stochastic dominance over the 25 ha/y (ca. NZ$24,000) and continuation of the status quo (ca. NZ$ 208.000) at a 6% discount rate. Pasture development should therefore continue. Stochastic analysis of the pasture development investment options gave a better insight into the likely outcomes for a project, and provides the farmer with more information for making a decision on whether, and how. to proceed with farm development. The model could easily be adapted for studying farm development with respect to other types of livestock enterprises Keywords: pastures, development, risk, feasibility, profitability, model

Singularidades na sintaxe do português brasileiro escrito na região nordeste nos séculos XIX e XX

In the disciplinary field of diachronic syntax, I present in this article a diatopic-diachronic mapping of the results of different studies of three morphosyntactic phenomena of Portuguese written in Brazil in the 19th and 20th centuries: the implementation of the pronoun você as a subject; the expression of the dative complement with reference to the second person singular; and the syntax of placement and position of clitic personal pronouns in simple sentences and in complex predicates. This diatopic-diachronic mapping allows me to bring up arguments in favor of the hypothesis that in the vast Brazilian territory of the 19th and 20th centuries the innovative forms of Brazilian Portuguese grammar are implemented with more expressiveness, already in late 19th century writing, first in the Northeast when compared to the Southeast and South regions. In writing in the Brazilian Northeast of the 19th century there are reflections of a system already implemented with the pronoun você in the function of subject, with the pronoun lhe as a dative complement of the second person singular, with an expressive increase of the prepositional forms (a/para + te/tu/you), and with a system of clitics with few cases of interpolation and contraction of clitics pronouns and innovative forms with proclisis in initial position of the period.No campo disciplinar da sintaxe diacrônica, apresento neste artigo um mapeamento diatópico-diacrônico de resultados de diferentes estudos de três fenômenos morfossintáticos do português escrito no Brasil dos séculos XIX e XX: a implementação do pronome você na função de sujeito; a expressão do complemento dativo com referência à segunda pessoa do singular; e a sintaxe de colocação e posição dos pronomes pessoais clíticos em sentenças finitas simples e em predicados complexos. Esse mapeamento diatópico-diacrônico me permite trazer à tona argumentos a favor da hipótese de que, no vasto território brasileiro oitocentista e novecentista, as formas inovadoras da gramática do Português Brasileiro são implementadas com mais expressividade, já na escrita do final do século XIX, primeiro na região Nordeste quando comparada às regiões Sudeste e Sul. Na escrita do século XIX, no Nordeste brasileiro, há reflexos de um sistema já implementado (1) com o pronome você na função de sujeito, (2) com o pronome lhe como forma de complemento dativo com referência à segunda pessoa do singular, com um aumento expressivo das formas preposicionadas (a/para + te/tu/você), e (3) com um sistema de clíticos com poucos casos de interpolação e contração de pronomes e formas inovadoras sem alçamento em complexos verbais e com próclise em posição inicial do período