Positivity and variational methods in second and fourth order boundary value problems

Tese de doutoramento, Matemática (Análise Matemática), Universidade de Lisboa, Faculdade de Ciências, 2010We study the existence of solutions for a nonlocal singular second order ordinary differential equation. We obtain results through Krasnoselskii’s fixed point Theorem and using some properties of the eigenvalues of the underlying singular linear problem and, on a different approach, through the monotone method associated with well-ordered lower and upper solutions. We deal with second and fourth order problems in infinite intervals, where we prove the existence of an homoclinic or an heteroclinic solution. For the second order we consider both superlinear and bounded nonlinearities, and prove existence results through variational methods. A non-variational approach was made for a second order problem with a dissipative term and a p-laplacian problem was also adressed. Simpler fourth order bvp’s were also tackled from a variational point of view. We also analyse fourth order boundary value problems related to beam deflection theory, generalizing some well known results for the second order. We analysed two types of problems: the case where the correspondent fourth order operator can be decomposed in two positive second order operators and the case where that cannot be done. The results are obtained through topological arguments in association with lower and upper solutions.Centro de Matemática e Aplicações Fundamentais (CMAF); PhD fellowship by Fundação para a Ciência e a Tecnologia (FCT)- ; FCT project POCI/MAT/57258/2004; ISE

Impact of heat stress on bovine sperm quality and competence

Áreas de pesquisa: Agriculture ; Veterinary Sciences ; Zoology - REVIEWGlobal warming has negatively influenced animal production performance, in addition to animal well-being and welfare, consequently impairing the economic sustainability of the livestock industry. Heat stress impact on male fertility is complex and multifactorial, with the fertilizing ability of spermatozoa affected by several pathways. Among the most significative changes are the increase in and accumulation of reactive oxygen species (ROS) causing lipid peroxidation and motility impairment. The exposure of DNA during the cell division of spermatogenesis makes it vulnerable to both ROS and apoptotic enzymes, while the subsequent post-meiotic DNA condensation makes restoration impossible, harming later embryonic development. Mitochondria are also susceptible to the loss of membrane potential and electron leakage during oxidative phosphorylation, lowering their energy production capacity under heat stress. Although cells are equipped with defense mechanisms against heat stress, heat insults that are too intense lead to cell death. Heat shock proteins (HSP) belong to a thermostable and stress-induced protein family, which eliminate protein clusters and are essential to proteostasis under heat stress. This review focuses on effects of heat stress on sperm quality and on the mechanisms leading to defective sperm under heat stress.info:eu-repo/semantics/publishedVersio

Matemática acessível: palestras que promovem a contextualização como ferramenta motivadora

 The importance of mathematics in the development of logical thinking and essential skills is undeniable. However, in Brazil, including in the State of São Paulo, indicators of the quality of mathematics learning, obtained in evaluations conducted at the state and national level, remain alarming. Resolving this situation is a key point in promoting the sustainable development of the country. In order to contribute to progress in this regard, at the local level, mathematics lecturers at the Chemistry Institute of UNESP in Araraquara developed an extension project called “Accessible Mathematics for Everyone”. The aim was to give talks in public schools in Araraquara and the wider region, focusing on the teaching of mathematics by means of contextualization, modeling, and problem solving. The intention was to motivate students to study and understand the subject, and to provide the teachers with new approaches to teaching the contents of the discipline, giving greater meaning to them. This article reports on the experience of this project and its first results, which have already been highly positive, especially in terms of encouraging the high school students to deepen their study of mathematics through scientific initiation projects supported by the PIBIC Jr - UNESP/CNPq  program. The partnership established between the lecturers involved in the project and the public schools has contributed to the development of these goals and has helped the high school students to pass the exams for entry to highly regarded public universities.La importancia de la matemática en el desarrollo del pensamiento lógico y las habilidades esenciales en la formación de un ciudadano es incuestionable, en Brasil, especialmente en Sao Paulo, los indicadores de competencia en la disciplina, obtenidos en las evaluaciones llevadas a cabo a nivel estatal, nacional y en todo el mundo, se mantiene en niveles alarmantes. Revertir esta situación es fundamental para promover el desarrollo sostenible del país y con el fin de dar una contribución a este respecto, aunque sólo sea a nivel local, los profesores de matemática del Instituto de Química de la UNESP, Araraquara, desarrollan un proyecto de extensión llamado "matemáticas accesible para todos", que tiene por objeto realizar conferencias en las escuelas públicas de Araraquara y la región, con la propuesta de enseñar matemáticas por medio de la contextualización, la modelación y resolución de problemas. Se espera motivar a los estudiantes para estudiar y comprender la disciplina, y también presentar a los profesores nuevas posibilidades para abordar el contenido, dando significado a los mismos. Este artículo cuenta la experiencia de este proyecto y sus primeros resultados, que ya han demonstrado ser muy positivos, sobre todo al despertar el interés delos estudiantes de secundaria en la promoción de sus estudios en matemáticas por medio de la investigación científica promovidas por el programa PIBIC Jr - UNESP / CNPq. La asociación establecida entre los profesores del proyecto y las escuelas públicas permitió la aplicación de estas directrices y el acceso de los estudiantes a las universidades públicas, por medio de pruebas.A importância da Matemática no desenvolvimento do raciocínio lógico e de habilidades essenciais na formação de um cidadão é inquestionável, porém no Brasil e, em particular no Estado de São Paulo, os indicadores de competência na matéria, obtidos nas avaliações realizadas no âmbito estadual, nacional e mundial, permanecem em níveis alarmantes. Reverter esta situação é fundamental para promover o desenvolvimento sustentável do país e, no intuito de dar alguma contribuição neste sentido, mesmo que somente em nível local, os docentes da área de Matemática do Instituto de Química da UNESP, Câmpus de Araraquara, desenvolvem um Projeto de Extensão denominado “Matemática acessível para todos” que tem por objetivo levar Palestras às escolas públicas de Araraquara e região, focadas na proposta de ensinar Matemática por meio da contextualização, modelagem e resolução de problemas. Espera-se com isso motivar os alunos a estudar e compreender a matéria, assim como apresentar aos docentes, novas possibilidades para abordar os conteúdos, dando significado aos mesmos. O presente artigo relata a experiência deste Projeto e seus primeiros resultados, que já vêm se mostrando bastante positivos, principalmente ao despertar nos alunos do Ensino Médio o interesse em aprofundar seus estudos em Matemática por meio da iniciação científica promovida pelo programa PIBIC Jr – UNESP/CNPq. A parceria estabelecida entre os docentes envolvidos no Projeto e as escolas públicas tem possibilitado a realização destas orientações e auxiliado no acesso destes alunos em excelentes universidades públicas, via vestibular

The Influence of (Poly)phenol Intake in Saliva Proteome: Short- and Medium-Term Effects of Apple

The relationship between salivary proteome and dietary habits was studied in previous works, where a relationship between salivary proteins like cystatins and polyphenol/tannin levels in diet was observed. However, it remains to be elucidated if this association results from an effect of polyphenol-rich food ingestion on saliva composition. The aim of this work was to test the effects of apple intake on the saliva proteome, both in the short and medium term (after 4 days of continuous intake). By incubating saliva samples with apple phenolic-rich extract, protein bands containing -amylase, S-type cystatins, and proline-rich proteins (PRPs) appeared in the fraction that precipitated, showing the potential of these (poly)phenols to precipitate salivary proteins. Among these, it was salivary cystatins that presented changes in their levels both in the saliva samples collected immediately after apple intake and in the ones collected after 4 days of intake of an extra amount of apple. These results support the thought that intake is reflected in the salivary proteome. The effect of a polyphenol-rich food, like the apple, on salivary cystatin levels is in line with results observed in animal models and, due to the involvement of these proteins in oral food perception, it would be interesting to explore in future studies the effect of these changes on sensory perception and acceptance of polyphenol-rich food.</jats:p

Matemática acessível: palestras que promovem a contextualização como ferramenta motivadora

A importância da Matemática no desenvolvimento do raciocínio lógico e de habilidades essenciais na formação de um cidadão é inquestionável, porém no Brasil e, em particular no Estado de São Paulo, os indicadores de competência na matéria, obtidos nas avaliações realizadas no âmbito estadual, nacional e mundial, permanecem em níveis alarmantes. Reverter esta situação é fundamental para promover o desenvolvimento sustentável do país e, no intuito de dar alguma contribuição neste sentido, mesmo que somente em nível local, os docentes da área de Matemática do Instituto de Química da UNESP, Câmpus de Araraquara, desenvolvem um Projeto de Extensão denominado “Matemática acessível para todos” que tem por objetivo levar Palestras às escolas públicas de Araraquara e região, focadas na proposta de ensinar Matemática por meio da contextualização, modelagem e resolução de problemas. Espera-se com isso motivar os alunos a estudar e compreender a matéria, assim como apresentar aos docentes, novas possibilidades para abordar os conteúdos, dando significado aos mesmos. O presente artigo relata a experiência deste Projeto e seus primeiros resultados, que já vêm se mostrando bastante positivos, principalmente ao despertar nos alunos do Ensino Médio o interesse em aprofundar seus estudos em Matemática por meio da iniciação científica promovida pelo programa PIBIC Jr – UNESP/CNPq. A parceria estabelecida entre os docentes envolvidos no Projeto e as escolas públicas tem possibilitado a realização destas orientações e auxiliado no acesso destes alunos em excelentes universidades públicas, via vestibular

Mechanical joining methods for additive manufactured assembly tools

The use of additive manufacturing (AM) processes is growing in the manufacturing industry. One application with great potential for using these processes is the manufacture of assembly tools for a high-ly competitive markets, such as the automotive industry. A critical aspect of the assembly tool design is its capability to incorporate modifications even at a late stage of its development in very short time. In many cases, these modifications are achieved using metal inserts in the polymeric tool, which allow to add new geometric features. This capability increases the usefulness and versatility of components produced by AM and compensate for potential shortcomings of using additive mate-rials. The purpose of this paper is to evaluate the potential use of accessories in additive manufactured com-ponents. In addition, the effect of different percentages of infill tool material on the joining quality of accesso-ries is evaluated. This is done by performing a screw pull-out test on a ABS ESD-7 part, produced by fused deposition modelling. The following different joining solutions were compared and studied in this work: em-bedded inserts, glue, heating processes, pressure (Tap-in) and creation of threads, such as, printing the thread directly and machining the thread onto the material.Programa Operacional Competitividade e Internacionalização - COMPETE 2020, Projeto nº 002814, Ref. POCI-01-0247-FEDER-002814 entre a Univ. do Minho e a Bosc

Presentation and validation of a new optical sensing concept based in a 3d-printing solution

In high competitive markets, such as the automotive industry, the better quality of products, reduction of manufacturing costs and the fulfilment of all delivery deadlines can only be achieved through continuous improvement of production capabilities. One current strategy is to develop and create smarter and adaptive assembly tools. Automation is a relevant area of development in the current industrial world and the baseline of the fourth industrial revolution (Industry 4.0). Namely, it is very important to use sensing components on jigs for assembly parts in the production line. The arrangement of sensing components on the assembly tools is very dependent of the product, making the project more complex and less flexible. This issue can penalise the productivity heavily, especially if a wide range of products and changeover operations are usual. The use of Additive Manufacturing (AM) is growing in the industry and offers a high potential for research and development in the present stage. The AM is advantageous in many areas, especially in the rapid construction of complex tools (RP). This paper presents a new optical sensing concept based on the 3D printing of internal circuits in the assembly tools. This solution can bring many advantages and increase tools flexibility.Programa Operacional de Competividade e Internacionalização - COMPETE 2020, Projeto nº 002814; Ref. POCI-01-0247-FEDER-002814, entre a Univ. Minho e a Bosc

Linking chemical exposure to lipid homeostasis: A municipal waste water treatment plant influent is obesogenic for zebrafish larvae

Obesity, a risk factor for the development of type-2 diabetes, hypertension, cardiovascular disease, hepatic steatosis and some cancers, has been ranked in the top 10 health risk in the world by the World Health Organization. Despite the growing body of literature evidencing an association between the obesity epidemic and specific chemical exposure across a wide range of animal taxa, very few studies assessed the effects of chemical mixtures and environmental samples on lipid homeostasis. Additionally, the mode of action of several chemicals reported to alter lipid homeostasis is still poorly understood. Aiming to fill some of these gaps, we combined an in vivo assay with the model species zebrafish (Danio rerio) to screen lipid accumulation and evaluate expression changes of key genes involved in lipid homeostasis, alongside with an in vitro transactivation assay using human and zebrafish nuclear receptors, retinoid X receptor α and peroxisome proliferator-activated receptor γ. Zebrafish larvae were exposed from 4 th day post-fertilization until the end of the experiment (day 18), to six different treatments: experimental control, solvent control, tributyltin at 100 ng/L Sn and 200 ng/L Sn (positive control), and wastewater treatment plant influent at 1.25% and 2.5%. Exposure to tributyltin and to 2.5% influent led to a significant accumulation of lipids, with white adipose tissue deposits concentrating in the perivisceral area. The highest in vitro tested influent concentration (10%) was able to significantly transactivate the human heterodimer PPARγ/RXRα, thus suggesting the presence in the influent of HsPPARγ/RXRα agonists. Our results demonstrate, for the first time, the ability of complex environmental samples from a municipal waste water treatment plant influent to induce lipid accumulation in zebrafish larvae.This work was supported by the Norte2020 and FEDER (Coral—Sustainable Ocean Exploitation—Norte-01-0145-FEDER-000036), by the Spanish Agencia Estatal de Investigación (CTM2017-84763-C3-2-R), the Galician Council of Culture, Education and Universities (ED431C2017/36) and FEDER/ERDF, and by the project NOR-WATER (0725), financed by “Programa de Cooperação Interreg Portugal/Espanha, (POCTEP) 2014-2020. Ricardo Capela was supported by grant SFRH/BD/112483/2015S

Use of illicit drugs, alcohol and tobacco in Spain and Portugal during the COVID-19 crisis in 2020 as measured by wastewater-based epidemiology

The COVID-19 pandemic spread rapidly worldwide in the year 2020, which was initially restrained by drastic mobility restrictions. In this work, we investigated the use of illicit drugs (amphetamine, methamphetamine, ecstasy, cocaine and cannabis), and licit substances of abuse (alcohol and tobacco) during the earlier months (March–July 2020) of the pandemic restrictions in four Spanish (Bilbao and its metropolitan area, Vitoria-Gasteiz, Castellón and Santiago de Compostela) and two Portuguese (Porto and Vila do Conde) locations by wastewater-based epidemiology (WBE). The results show that no methamphetamine was detected in any of the locations monitored, while amphetamine use was only detectable in the two locations from the Basque Country (Bilbao and its metropolitan area and Vitoria-Gasteiz), with high estimated average usage rates (700–930 mg day−1 1000 inhabitant−1). The remaining substances were detected in all the investigated catchment areas. In general, no remarkable changes were found in population normalized loads compared to former years, except for cocaine (i.e. its main metabolite, benzoylecgonine). For this drug, a notable decrease in use was discernible in Castellón, while its usage in Porto and Santiago de Compostela seemed to continue in a rising trend, already initiated in former years. Furthermore, two events of ecstasy (3,4-methylenedioxymethamphetamine, MDMA) dumping in the sewage network were confirmed by enantiomeric analysis, one in Santiago de Compostela just prior the lockdown and the second one in the Bilbao and its metropolitan area in July after relieving the more stringent measures. The latter could also be associated with a police intervention. The comparison of WBE with (web) survey data, which do not provide information at a local level, points towards contradictory conclusions for some of the substances, thereby highlighting the need for stable WBE networks capable of near real-time monitoring drug useThis research was funded by the Spanish Agencia Estatal de Investigación – MCIN/AEI/10.13039/501100011033 (CTM2016-81935-REDT, PID2020-117686RB-C32 and PID2020-117686RB-C31), Consellería de Cultura de Galicia, Educación e Universidades (ED481A-2020/258 and ED431C 2021/06), Delegación del Gobierno para el Plan Nacional Sobre Drogas (2020I009), Instituto de Salud Carlos III-Next Generation EU (RD21/0009/0012 – RIAPAd Network), Generalitat Valenciana (Research Group of Excellence Prometeo 2019/040), Fundación Vital (Vitoria-Gasteiz) and Ayuntamiento de Vitoria-GasteizS