No abstract

Plasmonic nanofluids, based on metal nanoparticles (NPs), has received tremendous attention for its potential to increase the efficiency of solar energy harvesting and harnessing systems. The ability to manage their optical absorption by tuning localized surface plasmon (LSP) bands is the reason why metal NPs are considered excellent nanoheaters with unique thermo-optic properties. In this work, we demostrate the influence of the tuning of plasmonic nanofluid absorption bands in different spectral regions, by modifying the morphology and size of the core–shell NPs, on the efficiency of plasmonic nanoheaters to heat fluids and generate steam. Five plasmonic nanofluids containing spherical Au@SiO2, rodlike Au@SiO2, with three different aspect ratios, and spherical SiO2@Au nanoshells were fabricated and characterized to study the local heating induced by plasmon-enhanced light absorption. Gains of up to 28.3 times in the nanofluid temperature increase in direct absorption solar collectors (DASCs) and 7.5 times in the amount of steam generated in the solar ethanol distillation were measured from control over LSP resonances of spherical and rodlike core–shell NPs. Energy distribution analysis shows that plasmonic nanofluids present an efficient energy transfer management, dedicating ∼72% of the absorbed energy to heating liquids at low levels of solar irradiance. However, at high solar irradiances, the good spectral matching between the plasmonic nanofluid LSP bands and the solar irradiance spectrum promotes strong local heating around the core–shell NPs, allowing local temperatures above the boiling point to be reached. Under these conditions, plasmonic nanofluids spend a small amount of energy to heat liquids and they transfer ∼83% of the absorbed energy to generate steam. Thus, a 7.7-fold increase in solar ethanol vaporization rate was achieved. The experimental results, understood from the optical properties of core–shell plasmonic NPs by using the Maxwell–Garnett theoretical model, corroborate the importance of fabricating nanoheaters with projected geometries to maximize the efficiency of solar collectors and stills.

We present a new experimental procedure, based on the use of disordered light patterns, to improve the efficiency of random lasing and stimulated Raman scattering (SRS), which appear to be simultaneous and coupled at high intensities. A dual-regime random laser (RL) was achieved by using silver nanowires as scattering elements to induce an optical feedback in cavity-free lasers that use a Raman dye as the gain medium. It is shown that in the SRS-RL coupling regime, the random modulation of the pump intensity profile promotes efficient amplification of coherent Stokes photons in small randomly distributed regions, which simulate the formation of transverse laser modes. As a consequence, the spatial coherence of radiation emitted by the SRS-RL source can be tuned by managing the speckle contrast and the random wavevector distribution, corresponding to the parameters that define the degree of disorder introduced in the light pulses that pump the random lasing medium. Measurements of the 2D spatial intensitycorrelation function of the emitted fields were performed to evaluate the efficiency of disordered light to control the spatial coherence of SRS-RL.

O objetivo do presente relato de caso clínico foi descrever a reabilitação estética e funcional dos incisivos anteriores superiores de um paciente com bruxismo. Paciente do gênero masculino, 23 anos de idade, bruxoma, procurou tratamento para os dentes anteriores superiores devido aos diastemas dentários e também por causa dos comprimentos reduzidos dos incisivos centrais superiores. Para isso, foi realizada a gengivoplastia e osteotomia na região dos incisivos centrais superiores com o objetivo de melhorar as posições dos contornos gengivais e aumentar o comprimento desses dentes. Após 90 dias, o clareamento dentário foi realizado. Depois de 1 mês as facetas de resina composta foram confeccionadas nos incisivos centrais superiores. Durante o tratamento as necessidades e perspectivas do paciente foram levadas em consideração para alcançar o sucesso clínico. Após a conclusão dos procedimentos, o resultado fi nal foi satisfatório. Portanto, um plano de tratamento integrado se mostrou de extrema valia, principalmente quando o paciente é devidamente esclarecido das opções disponíveis de tratamento e colabora com o mesmo.

As florestas secundárias vêm substituindo as primárias que são suprimidas pela ação antrópica. Florestas tropicais secas são ecossistemas fortemente afetados por ações antrópicas. A serapilheira representa um importante estrato florestal, composta principalmente por material vegetal, que se decompõem, retorna a matéria orgânica para o ambiente e abriga uma rica teia trófica. Artrópodes atuam na quebra do material vegetal, aeração do solo e enriquecimento do solo com matéria orgânica, auxiliando na manutenção da decomposição da serapilheira. O objetivo deste estudo foi analisar a diversidade de artrópodes em fragmentos de floresta tropical seca em diferentes estádios de regeneração na estação seca e chuvosa. A diversidade de artrópodes nas estações seca e chuvosa foi analisada através de Perfis de diversidade de Hill; a diversidade beta foi calculada para verificar os padrões de substituição de espécies entre as áreas em diferentes estádios succesionais. As características funcionais foram comparadas através da distância de Gower e CWM. O estádio de regeneração intermediário foi mais rico e mais diversificado que os estádios iniciais e tardios. A beta diversidade foi relativamente baixa, sendo 0,195 o índice de Jaccard entre os três estádios na estação chuvosa e 0,294 para a estação seca. A guilda alimentar mais representativa foi dos herbívoros e o aparelho bucal mais comum o mastigador, não havendo diferenças significativas na distribuição das características funcionais. O estudo confirmou a importância da regeneração florestal sobre a estrutura da comunidade de artrópodes de serapilheira, que tem suas taxas de riqueza, padrões de dominância e diversidade variando de acordo com os estádios sucessionais. Effect of forest regeneration on the diversity of litter arthropods A B S T R A C TSecondary forests have been replacing primary forests that are suppressed by anthropic action. Dry tropical forests are ecosystems strongly affected by human actions. The litter represents an important forest layer, composed mainly of plant material, which decomposes, returns organic matter to the environment and has a rich trophic web. Arthropods act in the breakdown of plant material, aeration of the soil and enrichment of the soil with organic matter, helping to maintain the decomposition of litter. The aim of this study was to analyze the diversity of arthropods in fragments of dry tropical forest at different stages of regeneration in the dry and rainy season. The diversity of arthropods in the dry and rainy seasons was analyzed using Hill's diversity profiles; beta diversity was calculated to verify species substitution patterns between areas at different successional stages. Functional characteristics were compared using Gower and CWM distance. The intermediate regeneration stage was richer and more diverse than the early and late stages. Beta diversity was relatively low, with 0.195 the Jaccard index between the three stages in the rainy season and 0.294 for the dry season. The most representative food guild was the herbivore and the most common mouthpiece was the chewer, with no significant differences in the distribution of functional characteristics. The study confirmed the importance of forest regeneration on the structure of the litter arthropod community, which has its rates of wealth, patterns of dominance and diversity varying according to successional stages.Keywords: Caatinga; chronosequence; edaphic fauna; ecological succession