Heavy metals effects on life traits of juveniles of Procambarus clarkii

An incubation experiment of juvenile crayfish (Procambarus clarkii) following a three- level treatment design approach was performed to assess the effect of different heavy metal concentrations on their life history traits (lifespan, growth, moult and feeding activity). The aims were to: (1) address the response of the life traits; (2) check for the correlation between heavy metal concentrations in crayfish whole bodies with the ones of the experimental solutions; (3) analyse the variation of crayfish carbon and nitrogen stable isotopes signatures grown under these treatments. Treatments were: control or absence of pollutants (C); low level contamination (L) similar to those found in the water of the Guadiamar River (SW, Spain) one year after the Aznalcóllar mine accident, and high level contamination (H) maximum concentrations of metals measured in the water of the river after the spill. The study concludes that the H treatment produced lethal effects on juveniles of crayfish, whereas those undergoing the L treatment showed less marked effects. Crayfish’s juveniles grown in L treatment seemed able to regulate and manage this range of pollution while maintaining their biological traits. Juvenile’s capacity to bioaccumulate toxic substances also changes with the nature of the particular metals. The reduction in lifespan was mainly influenced by Cu, Zn and As. 13C of C and juveniles from L treatment had similar values but different from those individuals of H treatment, reflecting the isotopic signature of the food source used (liver), and were also influenced by the concentration of Cu and AsThis work was part of the PICOVER program financed by the “Consejería de Medio Ambiente, Junta de Andalucía“ – Project title: Uso del cangrejo rojo americano (Procambarus clarkii) como especie centinela en el Corredor Verde del Guadiamar – Implicaciones de la especie en las redes tróficas – in 2002–200

Chiral Majorana Interference as a Source of Quantum Entanglement

Interferometry is a powerful tool for entanglement production and detection in multiterminal mesoscopic systems. Here we propose a setup to produce, manipulate and detect entanglement in the electron-hole degree of freedom by exploiting Andreev reflection on chiral one-dimensional channels via interferometry. We study the best possible case in which two-particle interferometry produces superpositions of maximally entangled states. This is achieved by mixing chiral Dirac channels through chiral Majorana modes. We show that it is possible to extract entanglement witnesses through current cross-correlation measurements.Comment: 5 pages, 1 figur

La historia como proyecto

En el contexto que nos ocupa, uno de los retos más apasionantes que se dibuja en los comienzos del siglo XXI constituye, sin duda, pensar i construir hipótesis plausibles que esclarezcan el presente del diseño y constituyan promesas para el futuro más inmediato. Junto a esta decidida mirada, atenta y escrutadora, dirigida siempre hacia delante, que se significa en la ingente y heterogénea producción de propuestas formales, la mirada restrospectiva, la permanente lección de la historia, clarifica y mide, relaciona y disocia, intrduce criterios de legibilidad en los producido al tiempo que propone modelos experimentados de intervención

Folk-lore, política y literatura popular en el siglo XIX (cartas inéditas de A. Machado y Álvarez a Teófilo Braga)

Neste artigo publicam-se, editam-se e comentam-se pela primeira vez as cartas enviadas pelo fundador da sociedade El Folk-Lore Español, Antonio Machado y Álvarez, ao ilustre polígrafo e líder português Teófilo Braga, conservadas actualmente na Biblioteca Pública e Arquivo de Ponta Delgada (Açores). Através destas treze cartas podemos conhecer mais em detalhe as estreitas relações entre os folcloristas portugueses e espanhóis no século XIX, assim como aprofundar as implicações ideológicas e políticas do inovador conceito de Folclore que ambos partilhavam. No final do artigo inclui-se um Apêndice bibliográfico de temas e autores portugueses nas publicações da sociedade de El Folk-Lore Español