Liquid crystal mobility and PDLC memory effects

Dissertation presented at Faculdade de Ciências e Tecnologia of Universidade Nova de Lisboa to obtain the Degree of Master in Chemical and Biochemical EngineeringPDLCs comprising PEGDA or PEGDMA as polymer matrix to support the liquid crystal E7 from Merck, in a ratio 30/70 (w/w) were studied. These were followed by thermal or photochemical polymerization of these mixtures by FTIR, where there was a similar rate of polymerization for both oligomers. Dielectric relaxation spectroscopy for the PDLC with E7 was used, where the polymer matrix was PEGDMA or PEGDA to study the liquid crystal mobility. The glass transition and the nematic-isotropic transition for E7 in both composites were studied, and the temperatures are consistent with those described in the literature for E7 and already observed by differential scanning calorimetry. The mobility of the liquid crystal alone and confined in the polymer matrix was compared, in a range of temperatures near the glass transition temperature (-60ºC to 0ºC). When an electric field is applied dominates the parallel alignment between all liquid crystal microdomains (the PDLC becomes transparent), after the application of an electric field, if it remains transparent, the PDLC have permanent memory effect. When temperature rise above the clear temperature, there is a phase transition, from the nematic phase to the isotropic phase. When the cell is cooled the liquid crystal molecules in the PDLC tend to align in each microdomain, however the microdomains are not aligned with each (PDLC presents opaque). The electro-optical properties of PDLC using PEGDA were studied in order to find permanent memory effects. It was found that composites have permanent memory effect by both thermal and photochemical polymerization, which was more pronounced than in the case of PEGDMA. The permanent memory effect was related with a parallel alignment of molecules of E7 and the mobility given by Dielectric Relaxation Spectroscopy

From trivium to smart education

[EN] Rethinking the classics for thinking the future. This could be the compendium of the present article, in which we propose a revision of the immediate future of education based on the classic project of the Trivium. We will analyze, first, the transformation of education in the perspective of smart education, determined by the impact of technology and by the reflection on the competences of the 21st century; secondly, we will review the strategic and methodological proposals in accordance with this transformation, based on the theory of generative learning; thirdly, from the point of view of contents, we will analyse the impor- tance of core digital skills as programming and computational thinking. On this basis, the paper offers a proposal from a dual perspective. Firstly, by rethinking the main issues of education in the light of the history of the Trivium and the epistemological principles that shaped it. Secondly, by proposing the recovery of the Trivium disciplines (Grammar, Rhetoric and Logic) having in mind the debate on the competences of the 21st century, as the best instrument to enrich the current educational systems, especially in view of the challenges of digitalization

Motivação académica: Suas relações com o autoconceito; género e desempenho académico

Segundo a teoria da autodeterminação os alunos podem estar intrinsecamente ou extrinsecamente motivados para realizar as tarefas escolares. Referem os autores que, embora originalmente motivados extrinsecamente, os alunos podem evoluir e vir a experimentar sentimentos de autonomia e melhorar a sua persistência na realização das atividades. Este processo tem sido associado, entre outros, ao autoconceito e desempenho académicos. O presente estudo pretende analisar em que medida os diferentes níveis de regulação para a aprendizagem (intrínseca, identificada, introjetada e externa) estão relacionados com o autoconceito académico, a autoestima, o ano de escolaridade, o género e o desempenho académico. Para o efeito participaram 454 alunos do distrito de Lisboa, a frequentar o 3º ciclo de escolaridade, dos quais 201 pertenciam ao género feminino. Para avaliar a regulação para a aprendizagem foi aplicada a Escala de Auto Regulação Académica “Porque é que eu faço as coisas?”, uma escala para avaliar o autoconceito académico (matemática e língua materna) e uma escala de autoestima. O desempenho académico foi avaliado atendendo à existência ou não de reprovações. Os resultados obtidos sugerem a existência de correlações positivas e significativas entre os níveis de regulação para a aprendizagem mais intrínseca, o auto conceito académico e a autoestima. Constataram-se, ainda, efeitos das variáveis género, ano de escolaridade e desempenho académico nos níveis de regulação para a aprendizagem.info:eu-repo/semantics/publishedVersio

A relação entre a aceitação/ rejeição parental, o ajustamento psicológico, o autoconceito académicos, a motivação para a aprendizagem e o desempenho académico do adolescente

Tese apresentada para cumprimento dos requisitos necessários à obtenção do grau de Doutor em Psicologia na área de especialização de Psicologia da Educação apresentada no ISPA - Instituto Universitário no ano de 2019.A presente pesquisa fundamenta se maioritariamente na teoria da aceitação/rejeição (IPARTheory) de Rohner (1986, 2004). Esta teoria defende que a dimensão do afeto parental varia segundo um continuum cujos extremos são a aceitação e a rejeição parental (Rohner, 2004). O afeto físico e psicológico é uma característica da aceitação parental. Por outro lado, a ausência de afeto pode assumir a forma de hostilidade e agressão, indiferença e negligência e, ainda, de rejeição indiferenciada. Estas assumem se como características da rejeição parental. A rejeição parental tem sido associada na literatura a várias consequências negativas como a possibilidade de desenvolvimento de perturbações emocionais e/ou comportamentais e o insucesso académico (Ali, 2011; Khaleque & Ali, 2017; Rohner, 2004, 2016; Tulviste & Rohner, 2010). Pretende se assim explorar em que medida a perceção de aceitação/rejeição parental contribui para o desempenho académico de sujeitos escolares a frequentar o 3º ciclo de escolaridade e testar o papel de certas variáveis individuais nomeadamente do ajustamento psicológico, autoconceito académico e motivação para a aprendizagem, no contexto desta relação. Para tal procedemos ao estudo das propriedades psicométricos dos instrumentos que utilizámos, tendo o mesmo revelado bons valores. Analisámos um modelo hipotético de variáveis, com base nas relações que haviam sido encontradas na literatura. Em termos globais, os resultados por nós obtidos apontam para o efeito direto da perceção de aceitação parental no desempenho académico dos alunos, e para o efeito indireto da perceção de aceitação materna e do ajustamento psicológico dos alunos no seu desempenho académico. Os resultados sustentam, ainda, o efeito das perceções de aceitação/rejeição parental, pai e mãe, no ajustamento psicológico dos filhos e para um efeito do ajustamento psicológico no autoconceito académico. Por sua vez, o autoconceito académico revelou efeito na motivação para a aprendizagem e, especialmente, no desempenho académico. Procedemos, ainda, a análises diferenciais em função do género e do ano de escolaridade. Os alunos revelaram, a nível geral, níveis adequados quanto à aceitação parental, pai e mãe e relativamente ao ajustamento psicológico. As raparigas e os rapazes não revelaram diferenças significativas, quanto às perceções de aceitação/rejeição materna e paterna, nem concernentes ao ajustamento psicológico. Apesar disso, os rapazes demonstraram percecionar mais agressão por parte do pai do que as raparigas. As raparigas revelaram níveis mais elevados de instabilidade emocional que os rapazes. Os alunos do 9º refletiram percecionar maiores níveis de rejeição parental, paterna e materna, que os alunos dos restantes anos. Foram também aqueles que evidenciaram uma visão mais negativa do mundo.The present research is based mainly on Rohner´s Interpersonal Acceptance/Rejection Theory (IPARTheory) (Rohner, 1986, 2004), which argues that the dimension of parental affection varies according to a continuum whose extremes are parental acceptance and rejection (Rohner, 2004). Physical and psychological affection is a characteristic of parental acceptance. On the other hand, the absence of affection may take the form of hostility and aggression, indifference and neglect, and even undifferentiated rejection. These are assumed to be characteristics of parental rejection. Parental rejection has been associated, in the literature, with a number of negative consequences, such as the possibility of developing emotional and/or behavioral disturbances and academic failure (Ali, 2011; Khaleque & Ali, 2017; Rohner, 2004, 2016; Tulviste & Rohner, 2010). The aim here is to explore the extent to which the perception of parental acceptance/rejection contributes to the academic performance of students attending 3rd cycle of schooling, and to test the role of certain individual variables, namely psychological adjustment, academic self-concept and motivation for learning , in the context of this relationship. We studied the psychometric properties of the instruments used. The same revealed good values. We analyzed a hypothetical model of variables, based on the relationships that had been found in the literature. Overall, our results point to the direct effect of parental acceptance perception on students' academic performance, and to the indirect effect of perceived maternal acceptance and psychological adjustment of students on their academic performance. The results also support the effect of parental acceptance/rejection perceptions, father and mother, on the psychological adjustment of the children and for an effect of psychological adjustment on academic self-concept. In turn, academic self-concept revealed an effect on motivation for learning and especially on academic performance. We also carried out differential analyzes according to gender and year of schooling. Students generally revealed adequate levels of parental acceptance, and psychological adjustment. Girls and boys did not reveal significant differences in perceptions of maternal and paternal acceptance/rejection, nor concerning psychological adjustment. Despite this, the boys showed more perceived paternal aggression than girls. Girls showed higher levels of emotional instability than boys. The students of the 9th year of schooling reflected higher levels of parental, paternal and maternal, rejection than students from the remaining years. They were also those who showed a more negative worldview

Usabilidad Web

[ES]La usabilidad es el grado en que un producto puede ser utilizado por los usuarios para lograr sus propósitos con efectividad, eficiencia y satisfacción en un determinado contexto de uso (ISO 9241-11). Se trata de conseguir productos que sean más fáciles de usar y que satisfagan mejor las necesidades reales de los clientes. Un diseño no es en sí mismo usable, lo es para usuarios específicos en contextos de uso específicos. Son varias las razones que nos llevan a realizar esfuerzos encaminados a cuidar los aspectos de usabilidad. No cabe duda de que un sitio Web con una buena usabilidad mejora su posición frente a sus competidores. En cualquier tipo de producto es deseable la facilidad de uso pero esto es especialmente importante en la Web, en la que un usuario que no se sienta cómodo o que encuentre dificultades para desenvolverse tiene una gran facilidad para buscar otro sitio que responda mejor a sus expectativas (recuérdese el tópico: “en la Web la competencia está a un clic de distancia”). En este capítulo se presentan bases sobre las que se asienta esta tecnología.[EN]Usability is the degree to which a product can be used by users to achieve their purposes with effectiveness, efficiency and satisfaction in a given context of use (ISO 9241-11). The aim is to achieve products that are easier to use and that better meet the real needs of customers. A design is not in itself usable, it is usable for specific users in specific contexts of use. There are several reasons that lead us to make efforts to take care of usability aspects. There is no doubt that a website with good usability improves its position in front of its competitors. Ease of use is desirable in any type of product, but this is especially important in the Web, where a user who does not feel comfortable or who finds it difficult to navigate has a great facility to find another site that better meets their expectations (remem-ber the topic: "on the Web the competition is a click away"). In this chapter we present the bases on which this technology is based

Técnicas de generación de contenido

[ES]HTML es una aplicación muy sencilla de las recomendaciones contenidas en el metalen-guaje SGML. A lo largo de este capítulo se presentará cómo surge en la evolución de los lenguajes de marcado el HTML y estudiaremos su sintaxis para realizar sencillas páginas web. Además se mostrarán los diferentes formatos con los que se trabaja y con los que se gestionan las hojas de estilo o CSS. HTML, XHTML y las hojas de estilo en cascada (CSS). Estos elementos son muy importantes para la creación de cualquier página web.[EN]HTML is a very simple application of the recommendations contained in the SGML meta-language. Throughout this chapter it will be presented how HTML emerges in the evolution of markup languages and we will study its syntax to make simple web pages. It will also show the different formats with which you work and with which you manage style sheets or CSS. HTML, XHTML and Cascading Style Sheets (CSS). These elements are very important for the creation of any web page

An ecological study

Funding Information: Tiago Jesus completed this work under an Advanced Rehabilitation Research Training grant from the National Institute on Disability, Independent Living, and Rehabilitation Research (NIDILRR) (grant number: 90ARHF0003). NIDILRR is a Center within the Administration for Community Living (ACL), Department of Health and Human Services (HHS). The contents of this publication do not necessarily represent the policy of NIDILRR, ACL, or HHS, and endorsement by the US Federal Government should not be assumed. Publisher Copyright: © 2023 John Wiley & Sons Ltd.Purpose: Towards informing health research policy and planning, this article evaluates the relationship of the research publications in cardiac rehabilitation (CR) and pulmonary rehabilitation (PR) with the rehabilitation needs arising from cardiovascular diseases (except stroke) and chronic respiratory diseases, over time (1990–2017).  Methods: Ecological study using a secondary analysis and linear regressions of public domain data to associate two datasets of population-level data: (1) research publications for CR and PR (data from the PubMed database); and (2) global need for CR and PR (data from the Global Burden of Disease study).  Results: The percentage of both CR and PR publications (among total rehabilitation research) significantly decreased from 1990 to 2017 (both: p < 0.01). PR needs and research publications were aligned: around 5% of total rehabilitation needs and rehabilitation research. For CR needs (around 2%, but significantly increasing since 1990), we found a greater portion of CR research publications (6.5% or over). Finally, we found an inverse association among the percentage of CR research publications and CR needs (b = −6.08; r2 = 0.37, p = 0.001).  Conclusion: The portion of CR and PR research (among total rehabilitation research) is declining over time. Yearly percentage of CR publications were greater than those of PR but for lower level of rehabilitation need, but the disparate trend was significantly decreasing over time. Population rehabilitation needs and their alignment with research volume must be one factor in the design of population-centred, equitable health research priorities.publishersversioninpres

Plataforma social para el fomento de la empleabilidad y el emprendimiento en la Facultad de Ciencias

Memoria ID-0016. Ayudas de la Universidad de Salamanca para la innovación docente, curso 2017-2018

Oral administration of zein-based nanoparticles reduces glycemia and improves glucose tolerance in rats

The aim was to evaluate the effect of zein-based nanoparticles on the glucose homeostasis, following oral administration to Wistar rats. For this purpose, bare nanoparticles (NP, with tropism for the upper intestinal regions) and poly(ethylene glycol)-coated nanoparticles (NP-PEG), with the capability to reach the ileum and cecum of animals, were evaluated. Both formulations were spherical in shape, displaying sizes around 200 nm and a negative surface zeta potential. The oral administration of a single dose of these nanoparticles to animals (50 mg/kg) induced a significant decrease of the glycemia, compared control rats and in animals treated with the free protein (p < 0.001). Moreover, these nanoparticles improved the glycemic control against an intraperitoneal glucose tolerance test; particularly NP-PEG. These findings would be due to an increased release of glucagon-like peptide-1 (GLP-1) by L-cells, which are more abundant in distal regions of the intestine. In fact, the GLP-1 blood levels of animals treated with nanoparticles were significantly higher than controls (about 40 % and 60 % for NP and NP-PEG groups, respectively). This higher capability of NP-PEG, with respect to NP, to increase the release of GLP-1 and control glycemia would be related to its ability to reach the distal areas of the small intestine

Development of a functional dark chocolate with baobab pulp

In recent years, cocoa and dark chocolate have attracted the interest of consumers not only for their sensory characteristics but also for their nutritional properties and positive impact on health. The baobab is a fruit of African origin with a sour and slightly sweet flavour, widely consumed by local communities due to its unique nutritional features. The aim of this work was to evaluate the impact of the concentration of baobab flour in the development of functional dark chocolate, including physical, chemical, nutritional and sensory evaluations. The results presented a positive correlation between the incorporation of baobab flour and the antioxidant activity (up to 2297 mmol TE/100 g), vitamin C content (up to 49.7 mg/100 g), calcium (up to 1052 mg/kg), potassium (up to 10,175 mg/kg), phosphorus (up to 795.9 mg/kg), chlorine (up to 235.4 mg/kg) and sulphur (up to 1158 mg/kg). The sensory evaluation of dark chocolate with 3% baobab presented the highest evaluation on the parameters “texture” and “overall flavour”, while the parameter “overall flavour” presented the lowest evaluation on chocolate with 9% baobab. No influence was observed on fatty acid profile, protein, fat and hardness