The silicon stable isotope distribution along the GEOVIDE section (GEOTRACES GA-01) of the North Atlantic Ocean

The stable isotope composition of dissolved silicon in seawater (δ30SiDSi) was examined at 10 stations along the GEOVIDE section (GEOTRACES GA-01), spanning the North Atlantic Ocean (40–60∘ N) and Labrador Sea. Variations in δ30SiDSi below 500 m were closely tied to the distribution of water masses. Higher δ30SiDSi values are associated with intermediate and deep water masses of northern Atlantic or Arctic Ocean origin, whilst lower δ30SiDSi values are associated with DSi-rich waters sourced ultimately from the Southern Ocean. Correspondingly, the lowest δ30SiDSi values were observed in the deep and abyssal eastern North Atlantic, where dense southern-sourced waters dominate. The extent to which the spreading of water masses influences the δ30SiDSi distribution is marked clearly by Labrador Sea Water (LSW), whose high δ30SiDSi signature is visible not only within its region of formation within the Labrador and Irminger seas, but also throughout the mid-depth western and eastern North Atlantic Ocean. Both δ30SiDSi and hydrographic parameters document the circulation of LSW into the eastern North Atlantic, where it overlies southern-sourced Lower Deep Water. The GEOVIDE δ30SiDSi distribution thus provides a clear view of the direct interaction between subpolar/polar water masses of northern and southern origin, and allow examination of the extent to which these far-field signals influence the local δ30SiDSi distribution

Signature of the interaction between dark energy and dark matter in observations

We investigate the effect of an interaction between dark energy and dark matter upon the dynamics of galaxy clusters. This effect is computed through the Layser-Irvine equation, which describes how an astrophysical system reaches virial equilibrium and was modified to include the dark interactions. Using observational data from almost 100 purportedly relaxed galaxy clusters we put constraints on the strength of the couplings in the dark sector. We compare our results with those from other observations and find that a positive (in the sense of energy flow from dark energy to dark matter) non vanishing interaction is consistent with the data within several standard deviations.Comment: 13 pages, 3 figures; matches PRD published versio

Tolerância de variedades de mamão (Carica papaya L.) à salinidade.

Nos Estados da Bahia e do Espírito Santo, principais regiões produtoras de mamão do Brasil, essa cultura está concentrada no ecossistema dos Tabuleiros Costeiros, onde são registradas, em alguns meses, precipitações inferiores à demanda. Assim, para que o mamoeiro alcance altas produtividades, o emprego de irrigações suplementares constitui-se em uma prática importante e imprescindível. Porém, um problema que se tem verificado nessas regiões é a qualidade da água dos poços, açudes e rios, que nem sempre é adequada ao crescimento normal das plantas, em razão, principalmente, da relativa alta concentração de sais. Em geral, a inibição do crescimento das plantas sob condições salinas é conseqüência de seus efeitos osmóticos, que pode induzir condições de estresse hídrico à planta e, ou, de efeitos dos íons Na+ e Cl-, que podem acarretar toxidez direta e desordens nutricionais. Apesar da importância desse problema, aspectos relacionados à sensibilidade do mamoeiro ao estresse salino não tem sido merecedores de estudos. Assim, o presente trabalho objetiva avaliar a resposta diferencial de variedades de mamoeiro à salinidade.PDF. 015

Chitosan and poly(Methyl methacrylate-co-butyl methacrylate) bioclends: a compatibility study.

Made available in DSpace on 2015-04-15T05:43:44Z (GMT). No. of bitstreams: 1 souza2014.pdf: 1629099 bytes, checksum: 2211f33daee6bb1d462adff4937e5ac3 (MD5) Previous issue date: 2015-04-14201

Métodos de extração de hidrocarbonetos policíclicos aromáticos em amostra de solo, sedimento e lodo.

bitstream/item/12265/1/documentos_79.pd

Calogênese in vitro de tecidos florais de cupuaçuzeiro.

Este trabalho teve como objetivo avaliar o processo inicial da morfogênese in vitro (calogênese) em tecidos florais do cupuaçuzeiro

Different hydrogen-bonded chains in the crystal structures of three alkyl N-[(E )-1-(2-benzylidene-1-methylhydrazinyl)-3- hydroxy-1-oxopropan-2-yl]carbamates

Peer reviewedPublisher PD