Landing on the Beaches: the Functioning of the Brazilian Slave Trade After 1831

Depois de 1831, o tráfico mudou-se para os portos naturais do litoral, passando a empregar muita gente em diversas atividades. Barcos menores apoiavam os navios negreiros a alcançar a costa. A população local passou a ter novas oportunidades de emprego e negócios. Os traficantes tiveram que comprar ou arrendar os portos naturais ou se associarem a seus proprietários. O tráfico mudaria a economia e a política local.After 1831, the slave trade moved to natural harbors on the littoral, where it employed scores of people catering, healing, guarding the survivors, burying the dead. Smaller boats also helped the slave ships to reach the coast. The local population found new opportunities of employment and trade. Slave dealers had to buy or rent those lands, or associate themselves with their owners. The illegal slave trade would change the local economy and politics

Trabalho, cotidiano, administração e negociação numa feitoria do tráfico no rio Benim em 1837

Em 1837, dois navios negreiros foram capturados no rio Benim (Nigéria) com documentos de uma feitoria do tráfico constituída para enviar cativos para Pernambuco. Os papéis encontrados descrevem as negociações da feitoria na bacia do rio Benim. Várias cartas dos empregados também foram encontradas, entre elas a correspondência do funcionário que tomava conta, alimentava e vigiava os cativos que seriam mandados para Pernambuco nos navios negreiros da empresa. Esses documentos revelam as rotinas cotidianas, as dificuldades, as práticas locais de negociação e outros detalhes das operações da feitoria no rio Benim, em que os empregados estavam em contato com a nobreza africana e com o Obá do poderoso reino do Benim.Palavras-chave: feitoria do tráfico - Osemwede - rio Benim - Azevedinho - Pernambuco

The osmotic pressure of charged colloidal suspensions: A unified approach to linearized Poisson-Boltzmann theory

We study theoretically the osmotic pressure of a suspension of charged objects (e.g., colloids, polyelectrolytes, clay platelets, etc.) dialyzed against an electrolyte solution using the cell model and linear Poisson-Boltzmann (PB) theory. From the volume derivative of the grand potential functional of linear theory we obtain two novel expressions for the osmotic pressure in terms of the potential- or ion-profiles, neither of which coincides with the expression known from nonlinear PB theory, namely, the density of microions at the cell boundary. We show that the range of validity of linearization depends strongly on the linearization point and proof that expansion about the selfconsistently determined average potential is optimal in several respects. For instance, screening inside the suspension is automatically described by the actual ionic strength, resulting in the correct asymptotics at high colloid concentration. Together with the analytical solution of the linear PB equation for cell models of arbitrary dimension and electrolyte composition explicit and very general formulas for the osmotic pressure ensue. A comparison with nonlinear PB theory is provided. Our analysis also shows that whether or not linear theory predicts a phase separation depends crucially on the precise definition of the pressure, showing that an improper choice could predict an artificial phase separation in systems as important as DNA in physiological salt solution.Comment: 16 pages, 5 figures, REVTeX4 styl

Phenotyping pipeline reveals major seedling root growth QTL in hexaploid wheat

Seedling root traits of wheat (Triticum aestivum L.) have been shown to be important for efficient establishment and linked to mature plant traits such as height and yield. A root phenotyping pipeline, consisting of a germination paper-based screen combined with image segmentation and analysis software, was developed and used to characterize seedling traits in 94 doubled haploid progeny derived from a cross between the winter wheat cultivars Rialto and Savannah. Field experiments were conducted to measure mature plant height, grain yield, and nitrogen (N) uptake in three sites over 2 years. In total, 29 quantitative trait loci (QTLs) for seedling root traits were identified. Two QTLs for grain yield and N uptake co-localize with root QTLs on chromosomes 2B and 7D, respectively. Of the 29 root QTLs identified, 11 were found to co-localize on 6D, with four of these achieving highly significant logarithm of odds scores (>20). These results suggest the presence of a major-effect gene regulating seedling root vigour/growth on chromosome 6D