Given a family of Abelian varieties over a positive-dimensional base, we prove that for a sufficiently general curve in the base, every rational section of the family over the curve is contained in a unique rational section over the entire base. 1. Main results sec-intro The starting point for this article is the following theorem. Theorem 1.1. [GHMS05, Theorem 6.2] Let B be a smooth, quasi-pro...

Historical data are widely used in river ecology to define reference conditions or to investigate the evolution of aquatic systems. Most studies rely on printed documents from the 19th century, thus missing pre-industrial states and human impacts. This article discusses historical sources that can be used to reconstruct the development of riverine fish communities from the Late Middle Ages unti...

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Let X/K be an absolutely simple abelian variety over a number field; we study whether the reductions Xp tend to be simple, too. We show that if End(X) is a definite quaternion algebra, then the reduction Xp is geometrically isogenous to the self-product of an absolutely simple abelian variety for p in a set of positive density, while if X is of Mumford type, then Xp is simple for almost all p. ...

Focusing on two determinant aspects of retail competition, prices and catchment area, this paper aims to specifically investigate the importance of the relative price density function. We answer such questions as whether it pays for a store to offer more low-priced items in a given category than its close competitors and whether a retailer should have a consistent assortment in terms of price t...

PURPOSE To investigate the association between home environment resources and the school performance of children from a public school in Belo Horizonte, Brazil, enrolled in the fourth year of the second cycle of Elementary School. METHODS This is a cross-sectional descriptive study in which 48 children aged between 8 and 12 years old participated. It included 28 boys, 20 girls, and their resp...