EMBL-EBI: moving, sharing and controlling large datasets

Supporting presentation slides as part of the Janet network end to end performance initiative

Two-magnon bound state causes ultrafast thermally induced magnetisation switching

There has been much interest recently in the discovery of thermally induced magnetisation switching using femtosecond laser excitation, where a ferrimagnetic system can be switched deterministically without an applied magnetic field. Experimental results suggest that the reversal occurs due to intrinsic material properties, but so far the microscopic mechanism responsible for reversal has not been identified. Using computational and analytic methods we show that the switching is caused by the excitation of two-magnon bound states, the properties of which are dependent on material factors. This discovery allows us to accurately predict the onset of switching and the identification of this mechanism will allow new classes of materials to be identified or designed for memory devices in the THz regime.

Induced spawning of African cat fish Clarias lazera (C. and V.) using acetone dried carp pituitary extract, deoxy-corticosterone acetate and human chorionic gonadotropin

A study was conducted to determine the efficacy of carp pituitary extract, deoxycorticosterone acetate, and human chorionic gonadotropin in inducing spawning in Clarias lazera . Results indicate deoxycorticosterone acetate to be more potent than pituitary extract, although the difference is not significant

Investment opportunities in fish seed technology

An examination is made of the requirements for the commercial propagation of carp and tilapia in Nigeria. It is concluded that the operation of a successful Fish Hatchery and fry production system will depend on the following factors: 1) Correct initial planning for intended production (both species and intended numbers); 2) Design of the appropriate facilities to enable required production; 3) Selection of top calibre, dedicated and experienced hatchery staff; and, 4) The ethical responsibility taken by the hatchery management to produce only the highest quality seed under the best possible conditions. Purchasing farmers are dependent on this

Studies in vortex motion

This thesis covers four different problems in the understanding of vortex sheets, and these are presented in four chapters.

In Chapter 1, free streamline theory is used to determine the steady solutions of an array of identical, hollow or stagnant core vortices in an inviscid, incompressible fluid. Assuming the array is symmetric to rotation through π radians about an axis through any vortex centre, there are two solutions or no solutions depending on whether A^(1/2)/L is less than or greater than 0.38 where A is the area of the vortex and L is the separation distance. Stability analysis shows that the more deformed shape is unstable to infinitesimal symmetric disturbances which leave the centres of the vortices undisplaced.

Chapter 2 is concerned with the roll-up of vortex sheets in homogeneous fluid. The flow over conventional and ring wings is used to test the method of Fink and Soh (1974). Despite modifications which improve the accuracy of the method, unphysical results occur. A possible explanation for this is that small scales are important and an alternate method based on "Cloud-in-Cell" techniques is introduced. The results show small scale growth and amalgamation into larger structures.

The motion of a buoyant pair of line vortices of opposite circulation is considered in Chapter 3. The density difference between the fluid carried by the vortices and the fluid outside is considered small, so that the Boussinesq approximation may be used. A macroscopic model is developed which shows the formation of a detrainment filament and this is included as a modification to the model. The results agree well with the numerical solution as developed by Hill (1975b) and show that after an initial slowdown, the vortices begin to accelerate downwards.

Chapter 4 reproduces completely a paper that has already been published (Baker, Barker, Bofah and Saffman (1974)) on the effect of "vortex wandering" on the measurement of velocity profiles of the trailing vortices behind a wing.

Desaprendendo o silêncio : uma experiência de trabalho com grupos de homens autores de violência contra a mulher

A presente dissertação problematiza as discussões sobre homens, masculinidades e violência contra a mulher, a partir de projetos de intervenção social os Grupos de Homens. Ao longo da história, homens e masculinidades ficaram invisíveis em relação a problemática de gênero e suas correlações com o campo da saúde. Essa invisibilidade produziu um silêncio acerca da condição masculina trazendo consequências para a construção de narrativas de homens e mulheres. A questão da violência intrafamiliar, sobretudo da violência contra a mulher vem se constituindo em um grave problema de saúde pública no Brasil e demais países. Este tipo de violência cometida por homens está conectado a forma pela qual os homens exercem sua masculinidade. Partindo de estudos do construcionismo social sobre gênero, masculinidades e violência, o autor aponta os Grupos de Homens espaços masculinos de reflexão como um dispositivo de intervenção social que caminha na direção de relações de gênero mais justas e equitativas entre homens e mulheres.

The pyrolysis of n-butane

A study of the pyrolysis of n-butane was carried out using an all-gold tubular reactor. The initial rate of decomposition of the n-butane was of 1.50-order with respect to the partial pressure of the n-butane. A free radical mechanism, similar to that originally proposed by Rice, accounted satisfactorily for the distribution of products. Oxygen was rigorously excluded from the pyrolysis gases. The surfaces of the gold reactor had been acid-treated to remove oxide impurities. Some preliminary experiments were performed in the partial oxidation of n-butane.

Improváveis relações: produção de sentidos sobre o masculino no contexto de amizade entre homens homo e heterossexuais

Esta tese é um estudo acerca da produção de sentidos sobre a masculinidade e suas relações com a homofobia. Parte-se da premissa de que tanto a masculinidade quanto a homofobia são fenômenos construídos socialmente. A adoção do regime de amizade entre homens de orientações sexuais distintas permite problematizar as dinâmicas de gênero presentes nessa relação específica de homossociabilidade e suas interrelações com as diferentes concepções sobre masculinidade, homossexualidade e homofobia. A homofobia é compreendida sob duas perspectivas: (1) como um preconceito que gera discriminações e violências contra pessoas não heterossexuais; e (2) como um dispositivo regulador da relação entre homens, constituindo-se como um dos pilares da construção da masculinidade heterossexual. O trabalho de campo incluiu entrevistas individuais com homens heterossexuais de camadas médias das cidades do Rio de Janeiro e São Paulo que mantém relações de amizade com homens homossexuais. O conjunto dos participantes é heterogêneo no tocante à faixa etária (entre 25 e 47 anos), exercício profissional e experiências diversas de convívio com pessoas homossexuais. São analisadas as tensões, dilemas e ressignificações que ajudam a produzir diferentes sentidos para a masculinidade. Os resultados apontam para a coexistência de sentidos convencionais e liberais acerca do gênero e da sexualidade masculinos.

A comparison between circle hook and J hook performance in the dolphinfish, yellowfish tuna, and wahoo troll fishery off the coast of North Carolina

We compared numbers of strikes, proportions of fish that hooked up after strikes, proportions of fish that stayed on hook (retained) after hook up, and numbers of fish caught between circle and J hooks rigged with dead natural fish bait (ballyhoo)and trolled for three oceanic predator species: dolphinfish (Coryphaena hippurus), yellowfin tuna (Thunnus albacares), and wahoo (Acanthocybium solandri). Interactions were compared between circle and J hooks fished on 75 trips by two user groups (charter and recreational fishermen). Hooks were affixed to three species-specific leader types most commonly fished in this region: monofilament (dolphinfish), fluorocarbon (tuna), and wire (wahoo). Numbers of fish caught per trip and three potential mechanisms that might inf luence numbers caught (i.e., number of strikes, proportion of fish hooked, and proportion retained) were modeled with generalized linear models that considered hook type, leader type, species, user (fishing) group, and wave height as main effects. Hook type was a main effect at the catch level; generally, more fish were caught on J hooks than on circle hooks. The effect of hook type on strike rates was equivocal. However, J hooks had a greater proportion of hook-ups than did circle hooks. Finally, the proportion of fish retained once hooked was generally equal between hook types. We found similar results when data from additional species were pooled as a “tuna” group and a “mackerel” group. We conclude that J hooks are more effective than circle hooks at the hook-up level and result in greater numbers of troll-caught dolphinfish, tunas

Common carp (Cyprinus carpio) breeding in Nigeria

The development of the common carp (Cyprinus carpio) breeding programs in Nigeria is discussed.