Near-field interaction between domain walls in adjacent Permalloy nanowires

The magnetostatic interaction between two oppositely charged transverse domain walls (DWs)in adjacent Permalloy nanowires is experimentally demonstrated. The dependence of the pinning strength on wire separation is investigated for distances between 13 and 125 nm, and depinning fields up to 93 Oe are measured. The results can be described fully by considering the interaction between the full complex distribution of magnetic charge within rigid, isolated DWs. This suggests the DW internal structure is not appreciably disturbed by the pinning potential, and that they remain rigid although the pinning strength is significant. This work demonstrates the possibility of non-contact DW trapping without DW perturbation and full continuous flexibility of the pinning potential type and strength. The consequence of the interaction on DW based data storage schemes is evaluated.Comment: 4 pages, 4 figures, 1 page supplimentary material (supporting.ps

Satellite quenching and morphological transformation of galaxies in groups and clusters

We investigate the role that dense environments have on the quenching of star formation and the transformation of morphology for a sample of galaxies selected from the Sloan Digital Sky Survey. We make a distinction between galaxies falling into groups $(13 \leq \log{(M_{\text{halo}}/M_{\odot})} < 14)$ and clusters $(\log{(M_{\text{halo}}/M_{\odot})} \geq 14)$, and compare to a large sample of field galaxies. Using galaxy position in projected phase space as a proxy for time since infall, we study how galaxy specific star formation rate (sSFR) and morphology, parameterized by the bulge-to-total light ratio (B/T), change over time. After controlling for stellar mass, we find clear trends of increasing quenched and elliptical fractions as functions of infall time for galaxies falling into both groups and clusters. The trends are strongest for low mass galaxies falling into clusters. By computing quenching and morphological transformation timescales, we find evidence that star formation quenching occurs faster than morphological transformation in both environments. Comparing field galaxies to recently infalling galaxies, we determine there is pre-processing of both star formation and morphology, with pre-processing affecting star formation rates more strongly. Our analysis favours quenching mechanisms that act quickly to suppress star formation, while other mechanisms that act on longer timescales transform morphology through bulge growth and disc fading.Comment: 14 pages, 12 figures, accepted by MNRA

Development of microsatellite markers for Carapa guianensis (Aublet), a tree species from the Amazon forest.

Made available in DSpace on 2018-06-06T00:57:59Z (GMT). No. of bitstreams: 1 ID278071.pdf: 78621 bytes, checksum: 909dae31029c5902d64fbdf96ca46612 (MD5) Previous issue date: 2007-01-0

Casimir effect in a wormhole spacetime

We consider the Casimir effect for quantized massive scalar field with non-conformal coupling $\xi$ in a spacetime of wormhole whose throat is rounded by a spherical shell. In the framework of zeta-regularization approach we calculate a zero point energy of scalar field. We found that depending on values of coupling $\xi$, a mass of field $m$, and/or the throat's radius $a$ the Casimir force may be both attractive and repulsive, and even equals to zero.Comment: 2 figures, 10 pages, added 2 reference

The co-evolution of strong AGN and central galaxies in different environments

We exploit a sample of 80,000 SDSS central galaxies to investigate the effect of AGN feedback on their evolution. We trace the demographics of optically-selected AGN (Seyferts) as a function of their internal properties and environment. We find that the preeminence of AGN as the dominant ionising mechanism increases with stellar mass, overtaking star-formation for galaxies with $M_\text{stellar} \geq 10^{11}M_\odot$. The AGN fraction changes systematically with the galaxies' star-formation activity. Within the blue cloud, this fraction increases as star-formation activity declines, reaching a maximum near the green valley ($\sim 17 \pm 4\%$), followed by a decrease as the galaxies transition into the red sequence. This systematic trend provides evidence that AGN feedback plays a key role in regulating and suppressing star formation. In general, Seyfert central galaxies achieve an early-type morphology while they still host residual star formation. This suggests that, in all environments, the morphology of Seyfert galaxies evolves from late- to early-type before their star formation is fully quenched. Stellar mass plays an important role in this morphological transformation: while low mass systems tend to emerge from the green valley with an elliptical morphology (T-Type $\sim -2.5 \pm 0.7$), their high-mass counterparts maintain a spiral morphology deeper into the red sequence. In high-stellar-mass centrals, the fraction of Seyferts increases from early- to late-type galaxies, indicating that AGN feedback may be linked with the morphology and its transformation. Our analysis further suggests that AGN are fuelled by their own host halo gas reservoir, but when in group centrals can also increase their gas reservoir via interactions with satellite galaxies.Comment: 13 pages, 11 figures, accepted for publication in the MNRA

Avaliação bioeconômica da terminação de bovinos Canchim, machos e fêmeas, em confinamento.

O objetivo desse experimento, desenvolvido na Faculdade de Ciências Agrárias e Veterinárias/Unesp, em Jaboticabal, SP, foi avaliar os efeitos de dietas com silagem de milho ou com cana-de-açúcar e grãos de girassol e de diferentes condições sexuais de bovinos jovens sobre os resultados econômicos da terminação em confinamento. Foram utilizados 30 animais da raça Canchim, sendo 10 machos não castrados, 10 machos castrados e 10 novilhas, com 15 meses de idade e 289±16 kg de peso corporal. Os animais permaneceram alojados em baias individuais, durante 105 dias, tendo sido efetuadas pesagens no início do experimento e a cada 35 dias. Ao final do confinamento, todos os animais foram abatidos em frigorífico comercial. As remunerações obtidas com os animais que receberam dieta com silagem de milho, representadas pela taxa de remuneração mensal, foram superiores às principais aplicações disponíveis no mercado financeiro. Embora inferiores, os valores observados para os animais que receberam dietas à base de cana-de-açúcar foram também positivos. A utilização de machos castrados apresentou pior resultado, sendo a taxa de remuneração mensal obtida, inferior à poupança (0,63 % a.m.), que representa a aplicação financeira mais popular. Este resultado é reflexo do maior custo da dieta, valor de aquisição do animal e desempenho apresentado

Assembly of lightweight sandwich panels through joining by forming

This paper is focused on the assembly of lightweight sandwich panels built upon the patented ‘Opencell’ structure concept. The objective is to investigate the possibility of joining the connection members of the core to the adjoining skin sheet by plastic deformation at ambient temperature, instead of welding or adhesive bonding. The methodology draws from earlier developments of the authors in joining by forming using the mortise-and-tenon concept to experimentation and finite element modelling of the assembly process in unit cells that are representative of the sandwich panels. It is shown that replacing welding by joining by forming allows fabricating sandwich panels from sheet materials that are difficult or impossible to weld while preventing thermal cycles that are responsible for causing metallurgical changes, distortions, and residual stresses. Replacing adhesive bonding by joining by forming circumvents the need of surface preparation, time for the adhesive to cure and environmental compliance, among other requirementsinfo:eu-repo/semantics/publishedVersio

Avaliação de linhagens de feijão-caupi em Igarapé Açu-PA.

O estudo visou avaliar de forma preliminar os dados dos ensaios no município de Igarapé Açu-PA, incluindo a variabilidade genética, relação entre os componentes de produção e potencial produtivo. Foram testadas 40 linhagens de feijão-caupi, em dois ensaios: porte semi-ereto e ereto, em blocos inteiramente casualizados, com quatro repetições, em 2004 e 2005. Houve diferenças significativas entre as linhagens e anos, e interação linhagem ano para maioria dos caracteres agronômicos. A produtividade média das linhagens foi de 1.289,6kg/ha. O ano de 2004 apresentou maior precipitação e irradiação, resultando nas maiores produtividades médias. As linhagens do tipo semi-eretas mantiveram a produtividade média alta na mesma magnitude independente do ano. As linhagens apresentam variabilidade genética acima de 5%. O comprimento da haste principal apresentou a menor influencia ambiental e a maior correlação com a produtividade podendo ser indicada na seleção materiais promissores, assim como os componentes de produção como o número de semente por vagem e peso de 100 sementes