Effect of systemic administration of essential oils and main components on honeybee survival

Controlling bee diseases with non contaminant products is a challenge in apicultural research. Essential oils and their main components have been widely studied as alternative treatments for honeybee pathologies [1, 2, 3]. However, there is little information about prolonged systemic administration. The aim of this study was to evaluate, in laboratory assays, the effect of long term consumption of essential oils and main components. Oils were obtained by hydrodistillation from Laurus nobilis, Cinnamomun zeylanicum, Origanum vulgare, Rosmarinus officinalis and Eucalyptus spp. and were analyzed by gas chromatography. The main components administered were 1,8-cineol, β-myrcene, cinnamic aldehyde, carvacrol and α-phellandrene. Substances were administered ad libitum to newly emerged bees at concentrations of 0; 333; 3,333 and 6,666 ppm, on sucrose syrup, throughout 11-18 days. Mortality and substances consumption were measured daily. Survival analysis was performed using Gehan-Breslow test and pairwise multiple comparisons between survival curves (a= 0, 05). Substances consumption was analyzed using one way ANOVA. Bees that received cinnamon oil showed a lower survival than control at concentrations higher than 333 ppm (pvalues<0.001 ). Consumption of cinnamic aldehyde, the main component of this oil (79.3%), also caused lower survival at the same concentrations (p-values<0.001). Eucalyptus oil caused a lower survival rate when it was administered at 6,666 ppm, although 1,8 cineol, its main component (63.5%), was not toxic for bees at any concentration. Carvacrol, a main component of many oregano essential oils, showed toxic effects at 3,333 and 6,666 ppm. Essential oils did not cause differences in consumption rate (p= 0.275) while main components solutions, except for carvacrol, were less consumed than control at the three concentrations. Treatments did not cause dysentery to bees. Our results contribute to understanding the effect of repeated systemic doses of these substances, which is important to design long term pharmacological studies and treatments development

Near-field correlations in the two-photon field

Quantum Matter and Optic

Observation of near-field correlations in spontaneous parametric down-conversion

Quantum Matter and Optic

Type-I spontaneous parametric down-conversion with a strongly focused pump

Quantum Matter and Optic

Pore system changes of damaged Brazilian oxisols and nitosols induced by wet-dry cycles as seen in 2-D micromorphologic image analysis

Soil pore structure characterization using 2-D image analysis constitutes a simple method to obtain essential information related to soil porosity and pore size distribution (PSD). Such information is important to infer on soil quality, which is related to soil structure and transport processes inside the soil. Most of the time soils are submitted to wetting and drying cycles (W-D), which can cause important changes in soils with damaged structures. This report uses 2-D image analysis to evaluate possible modifications induced by W-D cycles on the structure of damaged soil samples. Samples of three tropical soils (Geric Ferralsol, GF; Eutric Nitosol, EN; and Rhodic Ferralsol, RF) were submitted to three treatments: 0WD, the control treatment in which samples were not submitted to any W-D cycle; 3WD and 9WD with samples submitted to 3 and 9 consecutive W-D cycles, respectively. It was observed that W-D cycles produced significant changes in large irregular pores of the GF and RF soils, and in rounded pores of the EN soil. Nevertheless, important changes in smaller pores (35, 75, and 150 µm) were also observed for all soils. As an overall consideration, it can be said that the use of image analysis helped to explain important changes in soil pore systems (shape, number, and size distribution) as consequence of W-D cycles.A caracterização da estrutura do solo usando a análise de imagens bidimensionais (2-D) constitui um método simples na obtenção de informações essenciais relacionadas com a porosidade do solo e a distribuição do tamanho de poros. Tal informação é importante para obter dados sobre a qualidade do solo, a qual está diretamente ligada à sua estrutura e aos processos de transporte que ocorrem no seu interior. Na maior parte do tempo os solos são submetidos a vários ciclos de umedecimento (wetting) e secamento (drying) (W-D) que podem causar importantes mudanças em solos que possuem estruturas danificadas. Neste estudo foi usada a análise de imagens em 2-D na avaliação de possíveis modificações devido a vários ciclos de W-D na estrutura de amostras de solo danificadas.Três solos diferentes em textura (Latossolo vermelho-amarelo distrófico - LVAd; Nitossolo vermelho eutrófico - NVe, Latossolo vermelho distrófico - LVd) foram submetidos a três diferentes tratamentos: 0WD, amostras controle não submetidas a nenhum ciclo de W-D; 3WD e 9WD, amostras submetidas a 3 e 9 ciclos consecutivos de W-D, respectivamente. Foi observado que os ciclos de W-D produziram mudanças significativas nos poros grandes irregulares dos solos LVAd e LVd e nos poros arredondados do NVe. Importantes mudanças nos poros de 35 até 150 µm foram observadas para todos os solos estudados. A partir dos resultados obtidos pode ser dito que o uso da análise de imagens auxiliou com sucesso na explicação de variações no sistema poroso (formato, número e distribuição de tamanho dos poros) devido aos ciclos de W-D para todos os solos analisados.Fundação AraucáriaEstado do Governo do Paraná - Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Elastoplastic and fracture behaviour of semi-crystalline polymers under multiaxial stress states

The deformation behaviour and fracture mechanisms of high-density polyethylene (HDPE), polypropylene (PP) and polyamide 6 (PA 6) are investigated experimentally under different stress states and at different crosshead speeds of 1, 20 and 200 mm/min. Fracture surface morphologies were investigated in a series of specimens tested at 200 mm/min under combined tension/shear loading at three different loading angles (α&nbsp;= 0°, 30° and 90°) at room temperature (RT) and 50 °C. In addition, the effects of notch profile radii (stress triaxiality) on HDPE, PP and PA 6 fracture behaviour have been studied at RT, using flat and cylindrical notched specimens. Specimens’ geometries were carefully designed to achieve various loading conditions and allowing to explore initial stress triaxialities ranged from 0 in pure shear loading (α&nbsp;= 0°) to a maximum of 0.84 for flat notched specimens with radius of 5 mm. The yield load shows an explicit dependency on temperature and crosshead speed. The fracture surfaces analysed reveals damage mechanisms such as crazing, void and cavitation formation. Two or more mechanisms are predominant, which means that the stresses along fracture process are not uniform

Measurement of the spiral spectrum of entangled two-photon states

Quantum Matter and Optic

Direct measurement of transverse-mode entanglement in two-photon states

Quantum Matter and Optic

Bosonic, fermionic, and anyonic symmetry in two-photon random scattering

033823Quantum Matter and Optic