Kinetic parameters estimation using the Paired Equivalent Isothermal Exposures (PEIE) Method under non-isothermal heating conditions

With the purpose of testing the recently developed Paired Equivalent Isothermal Exposures (PETE) method, to determine reaction kinetic parameters under nonisothermal conditions, continuous pasteurizations were carried out with a nectar of a tropical fruit [25% of Cupuacu (Theobroma grandiflorum) pulp and 15% of sugar] in order to estimate the ascorbic acid thermal degradation kinetic parameters. The experimental ascorbic acid thermal degradation activation energy (96±13kJ/mol) estimated by the PETE, compared well with the previously determined value (74±5kJ/mol) for the same product under isothermal conditions. The PETE method is a reliable, easy and faster method to estimate first order reactions activation energy

Test of Emotion Comprehension: Exploring the underlying structure through Confirmatory Factor Analysis and Similarity Structure Analysis

Some decades of research on emotional development have underlined the contribution of several domains to emotional understanding in childhood. Based on this research, Pons and colleagues (Pons & Harris, 2002; Pons, Harris & Rosnay, 2004) have proposed the Test of Emotion Comprehension (TEC) which assesses nine domains of emotional understanding, namely the recognition of emotions, based on facial expressions; the comprehension of external emotional causes; impact of desire on emotions; emotions based on beliefs; memory influence on emotions; possibility of emotional regulation; possibility of hiding an emotional state; having mixed emotions; contribution of morality to emotional experiences. This instrument was administered individually to 182 Portuguese children aged between 8 and 11 years, of 3rd and 4th grades, in public schools. Additionally, we used the Socially in Action-Peers (SAp) (Rocha, Candeias & Lopes da Silva, 2012) to assess TEC’s criterion-related validity. Mean differences results in TEC by gender and by socio-economic status (SES) were analyzed. The results of the TEC’s psychometric analysis were performed in terms of items’ sensitivity and reliability (stability, test-retest). Finally, in order to explore the theoretical structure underlying TEC a Confirmatory Factor Analysis and a Similarity Structure Analysis were computed. Implications of these findings for emotional understanding assessment and intervention in childhood are discussed

Efecto de extractos de hojas y frutos de Schinus molle sobre la estabilidad oxidativa de aceites mediante oxidación acelerada

The most highly recommended oils for the diet are those which are rich in unsaturated fatty acids. However, the presence of these components in the oils is related to oxidation, which can be determined by the induction period. Further safety and the prolongation of the storage period for such oils can be achieved by the addition of efficient antioxidants, which today are preferably from natural sources. In order to contribute to the related research, the main objective of this study was to evaluate the efficacy of Schinus molle extracts compared to synthetic antioxidants (BHT) in delaying the oxidation of some vegetable oils. The results of the present study showed that the fruit and leaf extracts of Schinus molle presented activities and potential for being used as antioxidants in vegetable oils based on the tested methods (DPPH and ABTS). The extracts were also characterized as containing phenolic compounds by the Folin Ciocalteau method and by high performance liquid chromatography (HPLC). The action of the extracts as natural antioxidants was proven in the vegetal oils of chia (Salvia hispanica) and peanut (Arachis hypogaea) by the Rancimat method. It was observed that the oils increased their resistance to oxidation when incorporated with the extracts of Schinus molle, and the extract from the leaves increased the induction period of peanut oil by more than three hours (from 19.5 to 22.9 hours) with an extract concentration of 2.5%. The fruit extract was more efficient in delaying the oxidation of chia oil, prolonging its induction period by more than one hour with a concentration of 2.5% (from 3.1 to 4.3 hours). According to the results, the extracts of Schinus molle have favorable properties for possible use as an additive which inhibits the oxidation process of the tested vegetables oils.Los aceites más recomendados para la dieta son los ricos en ácidos grasos insa­turados. Sin embargo, la presencia de estos componentes está relacionada con la oxidación del aceite, que puede determinarse por el período de inducción. La seguridad adicional de tales aceites y la prolongación del almacenamiento se pueden lograr mediante la adición de antioxidantes eficientes, que hoy en día se prefieren los provenientes de fuentes naturales. Para contribuir con estas investigaciones, el objetivo principal de este estudio fue evaluar la eficacia de los extractos de Schinus molle en comparación con el antioxidante sintético BHT, para retrasar la oxidación de algunos aceites vegetales. Los resultados del presente estudio mostraron que los extractos de frutas y hojas de Schinus molle presentan potencial para ser utilizados como antioxidan­tes en aceites vegetales, presentando actividades basadas en métodos probados, DPPH y ABTS. Los extrac­tos también se caracterizaron por la presencia de compuestos fenólicos determinados mediante el método de Folin Ciocalteau y por cromatografía líquida de alta resolución (HPLC). La acción de los extractos como antioxidantes naturales se evidenció en aceites vegetales de chía (Salvia hispanica) y maní (Arachis hypogaea) por el método Rancimat. Se observó que los aceites aumentan la resistencia a la oxidación cuando se le incor­poran extractos de Schinus molle, aumentando el periodo de inducción en más de tres horas (de 19,5 a 22,9 horas) del aceite de cacahuete con una concentración de extracto del 2,5%. El extracto de fruta fue más efi­ciente en retrasar la oxidación del aceite de chia, prolongando el período de inducción de este aceite en más de una hora con una concentración del 2,5% (de 3,1 a 4,3 horas). De acuerdo con los resultados, los extractos de Schinus molle tienen propiedades favorables para un posible uso como un aditivo inhibidor del proceso de oxidación de los aceites vegetales ensayados

Resistive Random Access Memories (RRAMs) Based on Metal Nanoparticles

It is demonstrated that planar structures based on silver nanoparticleshosted in a polymer matrix show reliable and reproducible switching properties attractive for non-volatile memory applications. These systems can be programmed between a low conductance (off-state) and high conductance (on-state) with an on/off ratio of 3 orders of magnitude, large retention times and good cycle endurance. The planar structure design offers a series of advantages discussed in this contribution, which make it an ideal tool to elucidate the resistive switching phenomena

Adsortividade do herbicida "Zeta" em solos de variadas texturas

To estimate the herbicide rate which inhibits 50% (I50) of the growth of bioindicator plants in soils of different textures and organic matter levels, which could interfere on the bioactivity of the tested herbicide, a completely randomized experiment was carried out with seven treatments (0, 50, 100, 150, 200, 250 and 300 g a.i./ ha) and four replications, in five kinds of soil textures. The analyzed parameters were: total fresh biomass, dry shoot biomass and dry root biomass of the sorghum plants. According to the results, it can be concluded that in sandy soils the herbicide shows a great vertical mobility, and that high levels of AP+ in the soil can minimize the herbicide effect on plants. The experiment also has shown that the higher the level of active clays and of organic matter in the soil, the higher the rate of herbicide required for a given weed control level.Com o objetivo de estimar a dose do herbicida "Zeta" que inibe 50% I50) do crescimento de plantas bioindicadoras em solos com diferentes texturas e teores de matéria orgânica, podendo estes ter uma influência marcante sobre a bioatividade do herbicida testado, utilizou-se o delineamento experimental inteiramente casualizado com 7 tratamentos (0, 50, 100, 150, 200, 250 e 300 g i.a./ha) e 4 repetições, sendo os tratamentos dispostos em 5 tipos de texturas de solo. Os parâmetros avaliados foram: biomassa fresca total, biomassa seca da parte aérea e biomassa seca do sistema radicular das plantas de sorgo. De acordo com os resultados obtidos pode-se concluir que em solos com textura tendendo à arenosa o herbicida apresenta uma grande mobilidade vertical, e que altos teores de AP+ no solo podem mascarar, de certa forma, a atuação do herbicida na planta. Em linhas gerais, o experimento permitiu inferir que quanto maior os teores de argilas ativas e de matéria orgânica presentes no solo, maior a dose do herbicida requerida para um dado controle percentual de plantas daninhas

New electronic memory device concepts based on metal oxide-polymer nanostructures planer diodes

Nanostructure silver oxide thin films diodes can exhibit resistive switching effects. After an electroforming process the device can be programmed between a low conductance (off-state) and high conductance (on- state) with a voltage pulse and they are already being considered for non-volatile memory applications. However, the origin of programmable resistivity changes in a network of nanostructure silver oxide embedded in polymer is still a matter of debate. This work provides some results on a planer diode which may help to elucidate resistive switching phenomena in nanostructure metal oxide diodes. The XRD pattern after switching appears with different crystalline planes, plus temperature dependent studies reveal that conduction of both on and off states is weak thermal activated. Intriguing the carrier transport is the same for both on and off-states. Difference between states comes from the dramatic changes in the carrier density. The main mechanism of charge transport for on-state is tunneling. The charge transport leads to SCLC in higher voltages pulse for the off state. The mechanism will be explained based on percolation concepts

Theoretical description of phase coexistence in model C60

We have investigated the phase diagram of the Girifalco model of C60 fullerene in the framework provided by the MHNC and the SCOZA liquid state theories, and by a Perturbation Theory (PT), for the free energy of the solid phase. We present an extended assessment of such theories as set against a recent Monte Carlo study of the same model [D. Costa et al, J. Chem. Phys. 118:304 (2003)]. We have compared the theoretical predictions with the corresponding simulation results for several thermodynamic properties. Then we have determined the phase diagram of the model, by using either the SCOZA, or the MHNC, or the PT predictions for one of the coexisting phases, and the simulation data for the other phase, in order to separately ascertain the accuracy of each theory. It turns out that the overall appearance of the phase portrait is reproduced fairly well by all theories, with remarkable accuracy as for the melting line and the solid-vapor equilibrium. The MHNC and SCOZA results for the liquid-vapor coexistence, as well as for the corresponding critical points, are quite accurate. All results are discussed in terms of the basic assumptions underlying each theory. We have selected the MHNC for the fluid and the first-order PT for the solid phase, as the most accurate tools to investigate the phase behavior of the model in terms of purely theoretical approaches. The overall results appear as a robust benchmark for further theoretical investigations on higher order C(n>60) fullerenes, as well as on other fullerene-related materials, whose description can be based on a modelization similar to that adopted in this work.Comment: RevTeX4, 15 pages, 7 figures; submitted to Phys. Rev.

Constant Curvature Coefficients and Exact Solutions in Fractional Gravity and Geometric Mechanics

We study fractional configurations in gravity theories and Lagrange mechanics. The approach is based on Caputo fractional derivative which gives zero for actions on constants. We elaborate fractional geometric models of physical interactions and we formulate a method of nonholonomic deformations to other types of fractional derivatives. The main result of this paper consists in a proof that for corresponding classes of nonholonomic distributions a large class of physical theories are modelled as nonholonomic manifolds with constant matrix curvature. This allows us to encode the fractional dynamics of interactions and constraints into the geometry of curve flows and solitonic hierarchies.Comment: latex2e, 11pt, 27 pages, the variant accepted to CEJP; added and up-dated reference