On the methods of determining size/weight characteristics of food organisms of fish. (Determination of the length of Copepoda in larval stages by egg-laying females of the free living freshwater Copepoda). [Translation from: Voprosy Ikhtiologii 14, 182-194, 1960. ]

As is known, copepods play an important role in the nutrition of fish. Therefore with a view to facilitating research on the study of the quantitative side of feeding, there have recently appeared a considerable number of papers devoted to the development of methods for determining the wet. weight of these crustaceans. For the further facilitating of research in the nutrition of fish it would be of great interest to clarify the problem, is there not some kind of rule in the growth of the crustaceans during metamorphosis, and if there is such a rule is it not possible, to determine the length of the larvae at each stage, not by measuring them, but by using the formulae derived on the basis of these rules. This article examines the growth curves of different species of freshwater Copepoda, obtained on the basis of experimental observations in cultures or by way of measurement of mass material at all stages of development in samples from water-bodies. The authors study in particular the ratio of the mean diameter of the eggs to the mean length of the egg-bearing females.

Studies on the mouth size of fish larvae. Method and conclusions only [Translation from: Bulletin of the Japanese Society of Scientific Fisheries 36, 353-368, 1970]

This study was conducted to look into the relationship between mouth size and the total length of larval fish, and the growth in total length of larval fish in one or within a one-year period. Study material was gathered in the South China Sea, the Bay of Bangkok and the Vietnamese coast. This translation focuses on methods and conclusions of the original (longer) paper.

Ecological significance of seasonal variation in clutch-size of Arctodiaptomus bacillifer in alpine lakes of high altitudes (Val Bognanco) [Translation from: Bollettino di Zoologia 37 491-492, 1970]

This brief paper describes the significance of seasonal variation in clutch-size of the copepod Arctodiaptomus bacillifer in alpine lakes of high altitudes (Val Bognanco). Seasonal dynamics of the zooplankton of these lakes was studied during summer and autumn of 1968 and 1969and results are summarised.

The relationship between boat size and fish catches in the gillnet fishery of Lake Victoria, Uganda

The number and size composition of gillnets, fishing grounds, and the quantity and composition of fish catches were related to the size of fishing boat. The overall number of gillnets per boat increased from 20.9 + or - 2.3 nets in 5-6 m long boats to 88.6 + or - 11.8 nets in 11-12 m long boats. The proportion of large mesh sizes, + or more than 127 mm, also increased from 40% in 5-6 m long boats to 100% in boats longer than 10 m. Fish catches are related to the size of boat and this should be considered when formulating management guidelines of the lake's fishery. Promotion of large fishing boats 8 m or longer and restriction on the number and/or mesh size of gillnets of smaller boats could increase ecological and socio-economic benefits.

On the set of eigenvalues of a class of equimodular matrices

The structure of the set ϐ(A) of all eigenvalues of all complex matrices (elementwise) equimodular with a given n x n non-negative matrix A is studied. The problem was suggested by O. Taussky and some aspects have been studied by R. S. Varga and B.W. Levinger.

If every matrix equimodular with A is non-singular, then A is called regular. A new proof of the P. Camion-A.J. Hoffman characterization of regular matrices is given.

The set ϐ(A) consists of m ≤ n closed annuli centered at the origin. Each gap, ɤ, in this set can be associated with a class of regular matrices with a (unique) permutation, π(ɤ). The association depends on both the combinatorial structure of A and the size of the a_ii. Let A be associated with the set of r permutations, π₁, π₂,…, π_r, where each gap in ϐ(A) is associated with one of the π_k. Then r ≤ n, even when the complement of ϐ(A) has n+1 components. Further, if π(ɤ) is the identity, the real boundary points of ɤ are eigenvalues of real matrices equimodular with A. In particular, if A is essentially diagonally dominant, every real boundary point of ϐ(A) is an eigenvalues of a real matrix equimodular with A.

Several conjectures based on these results are made which if verified would constitute an extension of the Perron-Frobenius Theorem, and an algebraic method is introduced which unites the study of regular matrices with that of ϐ(A).

Current dependence of the energy gap in superconductors : a direct measurement

From the tunneling characteristics of a tin-tin oxide-lead junction, a direct measurement has been made of the energy-gap variation for a superconductor carrying a current in a compensated geometry. Throughout the region investigated – several temperatures near T_c and down to a reduced temperature t = 0.8 –the observed current dependence agrees quite well with predictions based on the Ginzburg-Landau-Gor’kov theory. Near T_c the predicted temperature dependence is also well verified, though deviations are observed at lower temperatures; even for the latter, the data are internally consistent with the temperature dependence of the experimental critical current. At the lowest temperature investigated, t = 0.8, a small “Josephson” tunneling current allowed further a direct measurement of the electron drift velocity at low current densities. From this, a preliminary experimental value of the critical velocity, believed to be the first reported, can be inferred in the basis of Ginzburg-Landau theory. For tin at t = 0.8, we find v_c = 87 m/sec. This value does not appear fully consistent with those predicted by recent theories for superconductors with short electronic mean-free-paths.

I. Stokes flow past a thin screen. II. Viscous flows past porous bodies of finite size

Part I

The slow, viscous flow past a thin screen is analyzed based on Stokes equations. The problem is reduced to an associated electric potential problem as introduced by Roscoe. Alternatively, the problem is formulated in terms of a Stokeslet distribution, which turns out to be equivalent to the first approach.

Special interest is directed towards the solution of the Stokes flow past a circular annulus. A "Stokeslet" formulation is used in this analysis. The problem is finally reduced to solving a Fredholm integral equation of the second kind. Numerical data for the drag coefficient and the mean velocity through the hole of the annulus are obtained.

Stokes flow past a circular screen with numerous holes is also attempted by assuming a set of approximate boundary conditions. An "electric potential" formulation is used, and the problem is also reduced to solving a Fredholm integral equation of the second kind. Drag coefficient and mean velocity through the screen are computed.

Part II

The purpose of this investigation is to formulate correctly a set of boundary conditions to be prescribed at the interface between a viscous flow region and a porous medium so that the problem of a viscous flow past a porous body can be solved.

General macroscopic equations of motion for flow through porous media are first derived by averaging Stokes equations over a volume element of the medium. These equations, including viscous stresses for the description, are more general than Darcy's law. They reduce to Darcy's law when the Darcy number becomes extremely small.

The interface boundary conditions of the first kind are then formulated with respect to the general macroscopic equations applied within the porous region. An application of such equations and boundary conditions to a Poiseuille shear flow problem demonstrates that there usually exists a thin interface layer immediately inside the porous medium in which the tangential velocity varies exponentially and Darcy's law does not apply.

With Darcy's law assumed within the porous region, interface boundary conditions of the second kind are established which relate the flow variables across the interface layer. The primary feature is a jump condition on the tangential velocity, which is found to be directly proportional to the normal gradient of the tangential velocity immediately outside the porous medium. This is in agreement with the experimental results of Beavers, et al.

The derived boundary conditions are applied in the solutions of two other problems: (1) Viscous flow between a rotating solid cylinder and a stationary porous cylinder, and (2) Stokes flow past a porous sphere.

O Município na federação brasileira: limites e possibilidades de uma organização assimétrica

A federação é uma forma de Estado adotada modernamente por mais de trinta Países, e consiste numa divisão territorial do poder entre um governo central e governos locais. No Brasil, esta divisão contempla um poder local-estadual e um poder local-municipal. A federação é assimétrica quando aos entes de mesmo nível (local-estadual ou local-municipal) são atribuídos diferentes regimes jurídicos, para compensar ou equilibrar suas diversidades. O chamado federalismo fiscal estuda as receitas e despesas dos entes que integram um Estado federal. No Brasil, sempre se adotou a simetria entre os municípios. Após a análise da posição do município brasileiro na questão fiscal (receitas, encargos e formas de redistribuição de recursos), identificam-se quatro pontos passíveis de mudança normativa, para seu aperfeiçoamento: brecha vertical, guerra fiscal, critérios para criação de municípios e regiões metropolitanas. As propostas formuladas na tese são: a mudança do paradigma da simetria, instituindo-se um regime especial para os municípios com população inferior a dez mil habitantes; a proibição de que sejam criados novos municípios com este porte; novos critérios e procedimentos para criação de municípios; instituição de um conselho de municípios, junto ao Senado Federal; nova forma de rateio do fundo de participação dos municípios, com a criação do fundo de participação das regiões metropolitanas; a serem criadas pela União e geridas através de conselhos formados pelos municípios e Estados-membros participantes, na proporção de sua população, área e economia.

Core size scaling of helical-core optical fibres

The mode-area, scaling properties of helical-core optical fibres are numerically studied and the limit of core size for achievable single-mode operation is explored. By appropriate design, helical-core fibres can operate in a single mode with possible scaling up to 300 mu m in core diameter with numerical aperture 0.1.

O que faz do conselheiro Aires um cético?

Há um consenso nos meios crítico e acadêmico de que Joaquim Maria Machado de Assis é o maior ficcionista brasileiro. Além da qualidade inegável, sua ficção é notável por sua dimensão, atingindo uma dezena de romances e mais de duzentos contos. Com esta união singular entre extensão e qualidade, a obra machadiana acumulou a maior fortuna crítica no Brasil e uma das maiores da literatura universal. Ainda assim, sua fortuna é a que mais cresce no Brasil. Diante de tamanha dedicação dos estudiosos, em que seria relevante a apresentação de mais uma dissertação sobre o Bruxo do Cosme Velho? Acreditando que, apesar do tamanho da investigação que já se fez sobre Machado, alguns dos aspectos cruciais da vida e da obra do escritor ainda não foram devidamente elucidados, este trabalho nasce com a intenção de contribuir para a diminuição dessa lacuna. Um desses aspectos é o conteúdo filosófico da ficção machadiana. Durante muitas décadas, a ideia de que Machado de Assis se alinhara filosoficamente ao pessimismo foi hegemônica. Entretanto, muitas características da ficção machadiana, tais como o humour e a ironia, podem ser sinais de outra orientação filosófica: o ceticismo. A identificação entre Machado e ceticismo não é, entretanto, algo novo, mas durante a maior parte do tempo, a crítica identificou o ceticismo de Machado com a acepção popular do termo: descrença no campo metafísico e desengano no campo político-social. Este modo de ver o ceticismo acaba por aproximar o termo, e reaproximar Machado de Assis, ao pessimismo. Por outro lado, há algumas décadas, alguns estudiosos brasileiros começaram a verificar que a filosofia da ficção machadiana estaria de fato associada ao ceticismo, mas a outro tipo de ceticismo, o ceticismo pirrônico ou filosófico, iniciado com Pirro de Elis, filósofo grego que viveu entre 360 e 270 a.C., e estabelecido pelos escritos de Sexto Empírico, filósofo e médico do século 2. Fazendo jus à origem grega do termo skepticós, aquele que investiga, o ceticismo pirrônico prima não pela descrença, mas pela busca contínua da verdade. Esta busca se mantém indeterminada em virtude da limitação dos sentidos e do pensamento humanos. Não podemos alcançar a verdade das coisas, mas apenas descrever como elas aparentam. Esta impossibilidade não conduz o pirrônico ao pessimismo, o conduz, ao contrário, à tranquilidade, pois ele aceita a sua limitação, não fica se debatendo contra ela. Na ficção machadiana, o conselheiro Aires é o personagem cético por excelência, a começar pelo tão famoso tédio à controvérsia. Entretanto, apesar da semelhança entre a ficção de Machado de Assis e a filosofia cética, há um problema a ser enfrentado: como o escritor poderia ter criado um personagem tão próximo do pirronismo se Machado nunca chegou a ler uma página de Sexto Empírico?

Effect of the A cation size disorder and synthesis conditions on the properties of an iron perovskite series

Póster presentado en The Energy and Materials Research Conference - EMR2015 celebrado en Madrid (España) entre el 25-27 de febrero de 2015