Hasse--Schmidt derivations versus classical derivations

In this paper we survey the notion and basic results on multivariate Hasse--Schmidt derivations over arbitrary commutative algebras and we associate to such an object a family of classical derivations. We study the behavior of these derivations under the action of substitution maps and we prove that, in characteristic $0$, the original multivariate Hasse--Schmidt derivation can be recovered from the associated family of classical derivations. Our constructions generalize a previous one by M. Mirzavaziri in the case of a base field of characteristic $0$.Comment: Dedicated to L\^e D\~ung Tr\'ang; final version; 2 references added; minor corrections. arXiv admin note: text overlap with arXiv:1807.10193, arXiv:1903.0898

Hasse--Schmidt modules versus integrable connections

We prove that, in characteristic 0, any Hasse-Schmidt module structure can be recovered from its underlying integrable connection, and consequently Hasse--Schmidt modules and modules endowed with an integrable connection coincide.Comment: 20 pages; comments are welcome. arXiv admin note: text overlap with arXiv:1810.08075, arXiv:1807.1019

Reinvigorating Old Ties: China and Latin America in the Tweny-First Century

Latin American Studie

First record of the starfish Luidia atlantidea in the Canary Islands

We document the first observations of Luidia atlantidea Madsen, 1950 (Luidiidae; Paxillosida, Asteroidea) along the coasts of the Canary Islands, which represents a new westward occurrence of its known range. Individuals were observed during a visual scuba diving census in the islands of Gran Canaria (northwestern and eastern coasts) and Tenerife (eastern coast). These occurrences highlight the importance of the systematic biodiversity monitoring and surveillance of the dynamic changes in the environment, whereas future research is required to reveal the underpinnings for its presence.info:eu-repo/semantics/publishedVersio

Evaluation of pressure boundary conditions for permeability calculations using the lattice-Boltzmann method

Lattice-Boltzmann (LB) simulations are a common tool to numerically estimate the permeability of porous media. For valuable results, the porous structure has to be well resolved resulting in a large computational effort as well as high memory demands. In order to estimate the permeability of realistic samples, it is of importance to not only implement very efficient codes, but also to choose the most appropriate simulation setup to achieve accurate results. With the focus on accuracy and computational effort, we present a comparison between different methods to apply an effective pressure gradient, efficient boundary conditions, as well as two LB implementations based on pore-matrix and pore-list data structures.Comment: 16 pages, 6 figure

Tautological systems and free divisors

We introduce tautological system defined by prehomogenous actions of reductive algebraic groups. If the complement of the open orbit is a linear free divisor satisfying a certain finiteness condition, we show that these systems underly mixed Hodge modules. A dimensional reduction is considered and gives rise to one-dimensional differential systems generalizing the quantum differential equation of projective spaces

Effects of galanin n-terminal fragment (1-15) in the light/dark and tail suspension tests

Galanin N-terminal fragment (1-15) [Gal(1-15)] is involved in mood regulation. The intracerebroventricular (icv) administration of Gal(1-15) produces a depressive-like behaviour in the forced swim test (FST) and an anxiety-like behaviour in the open field test (OF) in rats. In this work we analyze the effect of Gal(1-15) in two more behavioural tests, the tail suspension test (TLT) and the light/dark test. Gal(1-15) (3nmol), effective dose in FST and OF, or artificial cerebrospinal were injected in animals (n=5-8) 15 minutes before the test. Behavioural assessment were conducted with at least one week between tests. Student’s t-test was used for comparision between experimental groups. In the light/dark test we analyzed during 5 min three parametres as indicators of anxiety-like behaviour. Gal(1-15) significantly reduced the time spent in the light compartiment by 52% (p<0.05) and the latency time for entering the dark box by 65% (p<0.05). An increased in the latency time for re-entering the light box was also observed (p<0.05). In the TST, total immobility time was analyzed during 6 min test as parameter indicator of depressive-like behaviour. Gal(1-15) significantly increased rat immobility by 16% (p<0.05). Our results describe that Gal(1-15) exerts strong depressive- and anxiety-like effects in these tests, indicating a potential role of Gal(1-15) in mood disorders. These results may give the basis for the development of novel therapeutic drugs targeting Gal(1-15) for depression and anxiety.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Junta de Andalucia CVI6476 // Spanish Ministry of Economy and Competitiveness (PSI2013-44901-P to L.J.S). Author A.F-B. holds a ‘FPI’ grant from the Spanish Ministry of Economy and Competitiviness (grant number: BES-2014-068426)