The Surfaces of the Ceratonia siliqua L. (Carob) Leaflet: Insights from Physics and Chemistry.

The production of superhydrophobic coatings inspired by the surface of plant leaves is a challenging goal. Such coatings hold a bright technological future in niche markets of the aeronautical, space, naval, building, automobile, and biomedical sectors. This work is focused on the adaxial (top) and abaxial (bottom) surfaces of the leaflet of the Ceratonia silique L. (carob), a high-commercial-value Mediterranean tree cultivated in many regions of the world. The adaxial and abaxial surfaces feature hydrophobic and superhydrophobic behaviors, respectively. Their chemical composition is very simple: monopalmitin ester and palmitic acid are protuberant in the epicuticular and intracuticular wax layers of the adaxial surface, respectively, whereas 1-octacosanol dominates in the abaxial wax layers. In both surfaces, epicuticular wax is organized along a randomly oriented and intricate network of nanometer-thick and micrometer-long plates, whose density and degree of interconnection are significantly higher in the abaxial surface. The measured tilting angles for the abaxial surface (12-70°) reveal unusual variable density and water adhesion of the nanostructured plate-based texture. Optical measurements demonstrate that light reflectance/absorbance of the glaucous abaxial surface is significantly higher/lower than that of the nonglaucous adaxial surface. In both surfaces, diffuse reflectance is dominant, and the absorbance is weakly dependent on the light incidence angle. We show that the highly dense nanostructured platelike texture of the epicuticular abaxial layer of the C. siliqua leaflet works as a sophisticated light and water management system: it reflects solar radiation diffusely to lower the surface temperature, and it has superhydrophobic character to keep the surface dry. Such attributes enable efficient gas exchange (photosynthesis and respiration), transpiration, and evaporation. To mimic for the first time the abaxial surface, a templation approach was adopted using poly(dimethylsiloxane) (PDMS)/poly(methylphenylsiloxane) (PMPS) positive/negative replicas and a soft polymer/siloxane negative replica produced by the sol-gel process. Because high topographical variations of the biotemplate and wax adhesion to the biohybrid film affected the replication quality, the reproduction of the wax texture via the synthesis of 1-octacosanol-grafted siloxane-based hybrid materials is proposed as a suitable route to duplicate the abaxial surface with high fidelity. The natural chemical/physical strategy adopted by the C. siliqua leaflet to face the harsh Mediterranean climate is a powerful source of bioinspiration for the development of diffuse reflecting and superhydrophobic material systems with foreseen applications as dual-functional antiglare and water-repelling coatings.

Uma tipologia de modos de vida na aposentadoria em Portugal / A typology of retirement lifestyles in Portugal

O objetivo deste estudo é formular uma tipologia de modos de vida na aposentadoria, atendendo ao conjunto de recursos acumulados ao longo da trajetória de vida, sob a forma de bens (saúde, ambiente social, rendimento) e potencialidades (situação no trabalho, atividades fora do trabalho no passado, escolaridade, formação profissional). Foi usada a regressão logística para uma amostra de aposentados portugueses de ambos os sexos (N=499), com vista a clarificar o peso dessas variáveis em cada prática de aposentadoria. O resultado do modelo apresenta explicações plausíveis para quatro principais práticas de aposentadoria: retraimento, terceira idade, família, lazer, evidenciando os fatores que melhor explicam cada uma delas.(AU)

The aim of this study is to formulate a typology of retirement lifestyles considering a set of accumulated resources along the life course, in the form of goods (health, social environment, income) and potential (employment status, outside work activities in the past, education, vocational training). Logistic regression was used to a sample of Portuguese retirees of both sexes (N=499) in order to clarify the impact of these variables on each retirement practice. The result of the model presents plausible explanations for four main retirement practices: withdrawal, third age, family, leisure, highlighting the factors that best explain each one of them.(AU)

Uma tipologia de modos de vida na aposentadoria em Portugal / A typology of retirement lifestyles in Portugal

O objetivo deste estudo é formular uma tipologia de modos de vida na aposentadoria, atendendo ao conjunto de recursos acumulados ao longo da trajetória de vida, sob a forma de bens (saúde, ambiente social, rendimento) e potencialidades (situação no trabalho, atividades fora do trabalho no passado, escolaridade, formação profissional). Foi usada a regressão logística para uma amostra de aposentados portugueses de ambos os sexos (N=499), com vista a clarificar o peso dessas variáveis em cada prática de aposentadoria. O resultado do modelo apresenta explicações plausíveis para quatro principais práticas de aposentadoria: retraimento, terceira idade, família, lazer, evidenciando os fatores que melhor explicam cada uma delas.

The aim of this study is to formulate a typology of retirement lifestyles considering a set of accumulated resources along the life course, in the form of goods (health, social environment, income) and potential (employment status, outside work activities in the past, education, vocational training). Logistic regression was used to a sample of Portuguese retirees of both sexes (N=499) in order to clarify the impact of these variables on each retirement practice. The result of the model presents plausible explanations for four main retirement practices: withdrawal, third age, family, leisure, highlighting the factors that best explain each one of them.