Double dynamical regime of confined water

The Van Hove self correlation function of water confined in a silica pore is calculated from Molecular Dynamics trajectories upon supercooling. At long time in the $\alpha$ relaxation region we found that the behaviour of the real space time dependent correlators can be decomposed in a very slow, almost frozen, dynamics due to the bound water close to the substrate and a faster dynamics of the free water which resides far from the confining surface. For free water we confirm the evidences of an approach to a crossover mode coupling transition, previously found in Q space. In the short time region we found that the two dynamical regimes are overimposed and cannot be distinguished. This shows that the interplay between the slower and the faster dynamics emerges in going from early times to the $\alpha$ relaxation region, where a layer analysis of the dynamical properties can be performed.Comment: 6 pages with 9 figures. RevTeX. Accepted for pulbication in J. Phys. Cond. Mat

Anomalous relaxation kinetics and charge density wave correlations in underdoped BaPb1-xBixO3

Superconductivity often emerges in proximity of other symmetry-breaking ground states, such as antiferromagnetism or charge-density-wave (CDW) order. However, the subtle inter-relation of these phases remains poorly understood, and in some cases even the existence of short-range correlations for superconducting compositions is uncertain. In such circumstances, ultrafast experiments can provide new insights, by tracking the relaxation kinetics following excitation at frequencies related to the broken symmetry state. Here, we investigate the transient terahertz conductivity of BaPb1-xBixO3 - a material for which superconductivity is adjacent to a competing CDW phase - after optical excitation tuned to the CDW absorption band. In insulating BaBiO3 we observed an increase in conductivity and a subsequent relaxation, which are consistent with quasiparticles injection across a rigid semiconducting gap. In the doped compound BaPb0.72Bi0.28O3 (superconducting below Tc=7K), a similar response was also found immediately above Tc. This observation evidences the presence of a robust gap up to T=40 K, which is presumably associated with short-range CDW correlations. A qualitatively different behaviour was observed in the same material fo T>40 K. Here, the photo-conductivity was dominated by an enhancement in carrier mobility at constant density, suggestive of melting of the CDW correlations rather than excitation across an optical gap. The relaxation displayed a temperature dependent, Arrhenius-like kinetics, suggestive of the crossing of a free-energy barrier between two phases. These results support the existence of short-range CDW correlations above Tc in underdoped BaPb1-xBixO3, and provide new information on the dynamical interplay between superconductivity and charge order.Comment: 19 pages, 4 figure

Quantificação da arborização urbana viária de Campinas, SP.

A arborização urbana compreende parques, praças, jardins, bosques, fragmentos florestais, arborização particular e arborização viária, e é responsável por oferecer grandes benefícios à qualidade de vida da população das cidades. A arborização viária, em especial aquela que é disposta em calçadas, canteiros centrais e rotatórias, pode ser um grande entrave para o desenvolvimento sustentável das cidades caso não seja bem manejada. À medida que o adensamento urbano aumenta, o comércio se expande e a frota de automóveis atinge números astronômicos, calçadas são rebaixadas e as vias têm que ser ampliadas: reduz-se o espaço necessário à presença de árvores. Portanto, a gestão qualificada das árvores é primordial para a sustentabilidade das cidades.bitstream/item/82260/1/029-12.pd

Field induced evolution of regular and random 2D domain structures and shape of isolated domains in LiNbO₃ and LiTaO₃

The shapes of isolated domains produced by application of the uniform external electric field in different experimental conditions were investigated experimentally in single crystalline lithium niobate LiNbO3 and lithium tantalate LiTaO3. The study of the domain kinetics by computer simulation and experimentally by polarization reversal of the model structure using two-dimensional regular electrode pattern confirms applicability of the kinetic approach to explanation of the experimentally observed evolution of the domain shape and geometry of the domain structure. It has been shown that the fast domain walls strictly oriented along X directions appear after domain merging

Inventário quantitativo da arborização urbana viária de Campinas.

Pesquisas sobre arborização urbana têm se concentrado no inventário de árvores como forma de subsídio para os planos do governo. No entanto, um inventário total é extremamente trabalhoso de ser feito no campo. Para facilitar a observação das árvores, suas características e reduzir o tempo de busca, ferramentas de geoprocessamento estão permitindo obter resultados mais rápidos e confiáveis, criando possibilidades de exploração e conhecimento científico na análise ambiental e social. O objetivo desse trabalho foi o de propor uma nova metodologia para contar árvores nas cidades. Técnicas de geoprocessamento com imagens de alta resolução espacial foram utilizados para obter o número total de árvores do sistema viário da cidade de Campinas. O número de árvores, arbustos, palmeiras e mudas obtido foi validado em campo por meio de amostragem a partir de classes de densidade e frequência. O erro foi calculado e utilizado para estimar o número final. O total da arborização urbana do sistema viário em Campinas foi de 120.730 indivíduos, excluindo mudas. O erro encontrado foi de 16%, o que mostrou que a metodologia utilizada foi adequada para estimar a arborização total

Monitoring of arthropod infestations on high quality hard wheat in southern Italy

The results of a survey in 2006-2009 on high quality hard wheat, coming from 31 different storage centers located in Southern Italy, are reported. About 300 samples were analyzed by visual test, while 891 by both sieving and biological test. For the three different kinds of test the infesting species are listed and their relative incidence on the samples is reported. The most widespread species in the samples belonged to the order Coleoptera, i.e. Sitophilus granarius, Rhyzopertha dominica and Oryzaephilus spp., while Lepidoptera were less abundant. The results are discussed with the aim of providing the storage centre operators with helpful information on the correct monitoring strategies to adopt in case of arthropod infestations in high-quality hard-wheat warehouses.Keywords: Stored grain, Insects, Sampling, Coleoptera, Ital