Hours of work and retirement behavior

Using a novel dataset from the 2006 Portuguese Labor Force Survey this paper examines the impact of a voluntary reduction in hours of work, before retirement, on the moment of exit from the labor force. If, as often suggested, flexibility in hours of work is a useful measure to postpone retirement, then a reduction in working hours should be associated with retirement at later ages. Results prove otherwise suggesting that reducing hours of work before retirement is associated with early exits from the labor force. A reduction in hours of work seems to signal the worker’s wish to retire sooner rather than to announce the desire of remaining in the labor market.aging, retirement, working hours, older workers.

Hours of Work and Retirement Behavior

Using a novel dataset from the 2006 Portuguese Labor Force Survey this paper examines the impact of a voluntary reduction in hours of work, before retirement, on the moment of exit from the labor force. If, as often suggested, flexibility in hours of work is a useful measure to postpone retirement, then a reduction in working hours should be associated with retirement at later ages. Results prove otherwise suggesting that reducing hours of work before retirement is associated with early exits from the labor force. A reduction in hours of work seems to signal the worker's wish to retire sooner rather than to announce the desire of remaining in the labor market. This result may enclose the need for some alternative policy strategies regarding working hours.aging, retirement, working hours, older workers

Age and opportunities for promotion

Using a panel of new firms and their employees, this paper studies the promotion opportunities for older workers within the same firm. Survival analysis suggests that younger employees experience shorter times to promotion than older workers and, therefore, the latter face a smaller likelihood of promotion. Although men are promoted more often than women, empirical results show that women have shorter survival times to promotion than men. Also, previous promotions are stronger determinants of subsequent ones and this finding provides support to the evidence on promotion “fast-tracks”.aging, older workers, employment relationships, promotion

Portable sensor for impedance analysis in fruit

Electrical impedance spectroscopy (EIS) is a relatively new method applied to food quality assessment. It has been demonstrated that impedance measurement is capable of reflecting rapid changes when the food has any physical damage, such as chilling and bruising. Numerous studies have been made to devise accurate food quality measuring techniques. However, some of the new techniques, such as infra-red spectroscopy, or gas chromatography have expensive equipment and strict experimental environment requirements. In contrast, EIS allows relatively (1 order of magnitude) inexpensive assessment, is fast, easy to operate and non-invasive. It has been adopted for investigation of fundamental electrical properties of fruits. However, the sensors applied are laboratory equipment without viability in an industrial context or in the field. The applications of EIS for fruit analysis have been reported previously, the analytically relationships between electrical impedance properties and metabolic properties of the fruit have not yet been fully developed and more importantly the ability to classify fruits during the ripping process was not yet fully explored. This dissertation aims to investigate the electrical impedance properties of fruits and vegetables, and explore the relationship between impedance and quality criteria. It gives a description of a prototype impedance system based on the integrate system AD5933, which operates from a PC, with a software from “Analog Devices”. In particular, the present dissertation outlines experimental research conducted the impedance changes observed during ripening process. With the correct system calibration measurements on different fruits have been performed with results which clearly demonstrate the high potential of the technique for future applications on the field. The research was also devoted on the sensor calibration as well as system reliability. Statistical processing of the results using both, analise of variance (ANOVA) and signal processing techniques using multivariate data analysis, enable the differentiating types of fruits and stages of maturation. The results demonstrate that this system is a very promising technique, with exciting viability for further development to mobile devices suited to at line monitor the fruit quality has a great potential in assessing fruit ripening.A espectroscopia de impedância elétrica (EIS) é um método cuja aplicação na área da qualidade dos alimentos tem vindo a desenvolver-se. Diversos estudos demonstram que medições de impedância elétrica refletem alterações físicas nos alimentos. Nos últimos anos tem sido crescente a procura de novas técnicas para medição da qualidade dos alimentos. Contudo, algumas destas técnicas, tal como a espectroscopia de infravermelho, ou cromatografia gasosa, necessitam de equipamentos muito caros e de condições de medições especificas (laboratórios). A EIS utiliza equipamentos mais económicos, as medições podem ser realizadas em qualquer lugar (equipamentos portáteis), e são não invasivas. Na literatura é possível encontrar trabalhos com a aplicação do EIS em frutos, no entanto, a relação entre as propriedades dielétricas dos fruitos e o seu perfil metabólico ainda não foi totalmente explorado. Esta dissertação tem como objetivo investigar as propriedades elétricas dos frutos e relacionar com critérios de qualidade. Foi utilizado um sistema integrado de EIS, EVAL-AD5933, que opera a partir de um computador com o software da Analog Devices. A presente dissertação descreve medições de impedância em frutos, realizados durante o processo de amadurecimento. Os resultados deste trabalho indicam o elevado potencial da EIS para futuras aplicações no campo. Foi realizada a calibração do sensor e estudos de fiabilidade do sistema. Procedeu-se a um pré-processamento aos espectros de impedância através do software Unscrambler, incluindo técnicas de análise multivariada, que permitiram a redução do elevado volume de dados a um conjunto de variáveis que descrevem a variabilidade das amostras. Para validar os resultados obtidos foi construído um modelo que relaciona os valores de impedância das uvas com o respetivo brixº através de um PLS (Partial Least Square). Durante os testes realizados com o sensor foi possível concluir que as propriedades electricas dos fruitos permitem a sua caracterização tanto ao nível da espécie de fruto como do seu estado de maturação. Também foi possível criar um modelo de previsão de Brixº nas uvas a partir dos espectros de impedância. Os resultados demonstram que este sistema é promissor, com viabilidade para o desenvolvimento de futuros dispositivos com grande potencial para monitorizar o relógio metabólico dos frutos

Characterisation of a new Laser Guide Star Wavefront Sensor

openAdaptive Optics (AO) is a technology that improves the resolution of large telescopes by correcting aberrations introduced by the Earth’s atmosphere, enabling them to capture sharper astronomical images. Traditional AO relies on bright natural stars close to the science target for reference, limiting its use to specific areas of the sky. To overcome this limitation, scientists introduced the concept of Laser Guide Stars (LGS), such as sodium LGS. These artificial stars are created using lasers fired from the telescope position to excite the atomic sodium atmospheric layer, creating an elongated source in the sky. This unique nature of sodium LGS presented challenges for existing wavefront sensors used in AO systems. This thesis focuses on the Ingot Wavefront Sensor (I-WFS), a novel concept initially proposed by Ragazzoni and refined by the Adaptive Optics Group at the INAF-Osservatorio Astronomico di Padova. The I-WFS is designed to address the challenges posed by Sodium LGS and other LGS. It leverages the Scheimpflug principle to sense the full 3D volume of the elongated LGS. This innovative sensor is suitable for use in large telescopes. Currently it is designed to match the specifications of the European Extremely Large Telescope (E-ELT). My work has included the development of advanced algorithms for manipulating the LGS source on a screen, improving alignment procedures, and correcting systematic errors. I have also implemented a quasi closed-loop algorithm for autonomous monitoring and realignment. Ongoing research includes the development of a search algorithm and the integration of real sodium profiles using a new OLED screen. Our ultimate goal is to gain a comprehensive understanding of the I-WFS’s performance and its potential implementation in future Extremely Large Telescopes (ELTs) equipped with AO.Adaptive Optics (AO) is a technology that improves the resolution of large telescopes by correcting aberrations introduced by the Earth’s atmosphere, enabling them to capture sharper astronomical images. Traditional AO relies on bright natural stars close to the science target for reference, limiting its use to specific areas of the sky. To overcome this limitation, scientists introduced the concept of Laser Guide Stars (LGS), such as sodium LGS. These artificial stars are created using lasers fired from the telescope position to excite the atomic sodium atmospheric layer, creating an elongated source in the sky. This unique nature of sodium LGS presented challenges for existing wavefront sensors used in AO systems. This thesis focuses on the Ingot Wavefront Sensor (I-WFS), a novel concept initially proposed by Ragazzoni and refined by the Adaptive Optics Group at the INAF-Osservatorio Astronomico di Padova. The I-WFS is designed to address the challenges posed by Sodium LGS and other LGS. It leverages the Scheimpflug principle to sense the full 3D volume of the elongated LGS. This innovative sensor is suitable for use in large telescopes. Currently it is designed to match the specifications of the European Extremely Large Telescope (E-ELT). My work has included the development of advanced algorithms for manipulating the LGS source on a screen, improving alignment procedures, and correcting systematic errors. I have also implemented a quasi closed-loop algorithm for autonomous monitoring and realignment. Ongoing research includes the development of a search algorithm and the integration of real sodium profiles using a new OLED screen. Our ultimate goal is to gain a comprehensive understanding of the I-WFS’s performance and its potential implementation in future Extremely Large Telescopes (ELTs) equipped with AO

LocoMouse: a novel system for studying the role of cerebellum in gait coordination

Smooth and efficient walking requires the coordination of movement across different parts of the body. The cerebellum plays an important role in this process, yet the specific neural circuit mechanisms of whole-body coordination are poorly understood. Although sophisticated genetic tools exist to manipulate the cerebellar circuit in mice, analyses of mouse gait have typically been limited to gross performance measures and lack detail about precision and timing of limb movements. In this project, I developed an automated, high-throughput, markerless 3D tracking system (LocoMouse) for quantifying locomotion in freely walking mice. Using LocoMouse, I showed that locomotor parameters for individual limbs vary systematically with mouse walking speed and body size. In visibly ataxic Purkinje cell degeneration (pcd) and reeler mice, I found that 3D limb trajectories and, especially, interlimb and whole-body coordination are specifically impaired. Our findings suggest a failure to predict the consequences of movement across joints, limbs, and body. These experiments were essential to establish a quantitative framework for whole-body locomotor coordination in mice (Machado, Darmohray et al. eLife 2015). The LocoMouse system was then combined with optogenetic tools to ask how different output regions of the cerebellum differentially contribute to locomotor coordination. I expressed ChR2 in Purkinje cells and stimulated their terminals in the medial, interposed, and lateral cerebellar nuclei of freely walking mice. Here, I identified locomotor parameters that were specifically related to the manipulation of each nucleus. Acute disruption of neural activity in medial and interposed nuclei immediately perturbed ongoing locomotion. In contrast, similar manipulation of Purkinje cell inputs to the lateral nucleus had no observable effect on ongoing locomotor behavior. These results are broadly consistent with previous anatomical and lesion studies suggesting a medial-to-lateral functional organization of cerebellar outputs. Taken together, these experiments isolated impairments in interlimb and whole-body coordination in mice with cerebellar manipulations. In contrast, spinal cord mutant mice revealed impairments at the intralimb level with no alteration in the interlimb coordination. I characterized distinct motor deficits associated with manipulations in different brain regions and identified and quantified core features of cerebellar ataxia in mice. These experiments establish the LocoMouse system, combined with genetic manipulations, as a powerful system to dissect cerebellar circuit mechanisms of coordinated locomotion

Green synthesis of bioactive nanoparticles in algae from North Portugal

Dissertação de mestrado em Biologia Molecular, Biotecnologia e Bioempreendedorismo em PlantasIn recent years, the development of efficient green methods for synthesis of metal nanoparticles has emerged as an eco-friendly alternative for production of well-characterized nanoparticles instead of chemical processes which are more expensive and pollutant. Among the diverse techniques, plants, bacteria and fungi can be used in the synthesis. In a project focused on the green synthesis of new nanomaterials with biomedical application, the brown marine algae Cystoseira baccata was chosen as target specie for obtaining gold nanoparticles with antitumor activity. An efficient method for the biosynthesis of gold nanoparticles using C. baccata extract was developed by the research group led by Professor Maria C. Rodríguez-Argüelles (Vigo University, Spain) however further studies were necessary to clarify effects of the green synthesized gold nanoparticles in advanced in vitro and in vivo models to confirm them as effective, but non-toxic tools, for cancer therapies. Interestingly, a different species of Cystoseira is found in specific areas of coastal Northern Portugal, the Cystoseira tamariscifolia. Gold nanoparticles were produced using this specie, guided by the same protocol used with C. baccata and, similar toxicity and bioactivity studies were performed in order to understand if different members of the genus are capable of producing similar nanoparticles through green biosynthesis and evaluate its biocompability. To assess cell viability, MTT assay was performed, for cell proliferation the wound-healing assay was carried out and lastly, for in vivo evaluation, ZET assay was executed. The use of zebrafish embryos allowed to obtain toxicology data in complex organisms quickly and efficiently, permitting to conclude on multiple parameters at once. Finally, the results from the two algae extracts and derived nanoparticles were compared.Nos últimos anos, o desenvolvimento de métodos eficientes de “síntese verde” para a síntese de nanopartículas metálicas emergiu como uma alternativa ambientalista para a produção de nanopartículas bem caracterizadas, em vez dos processos químicos atuais que são mais caros e poluentes. Dentro das várias técnicas, plantas, bactérias e fungos podem ser usados na síntese. Num projeto focado na biossíntese de novos nanomateriais com aplicação biomédica, a alga marinha castanha Cystoseira baccata foi escolhida como espécie-alvo para obtenção de nanopartículas de ouro com atividade anti tumoral. Um método eficiente para a biossíntese de nanopartículas de ouro usando o extrato de C. baccatta foi desenvolvido pelo grupo de pesquisa liderado pela professora Maria C. Rodríguez-Argüelles (Universidade de Vigo, Espanha), contudo estudos adicionais são necessários para esclarecer os efeitos das nanopartículas de ouro produzidas por síntese verde podem ter em modelos in vitro e in vivo como alternativas eficazes mas não tóxicas para terapias contra o cancro. Curiosamente, uma espécie diferente de Cystoseira é encontrada em áreas específicas da costa norte de Portugal, a Cystoseira tamariscifolia. Nanopartículas de ouro foram produzidas nesta espécie, utilizando o mesmo protocolo usado com a C. baccata e, estudos semelhantes de toxicidade e bioatividade foram realizados para entender se todos os membros do género são capazes de produzir nanopartículas semelhantes com a biossíntese verde e avaliar a sua biocompatibilidade. Para avaliar a viabilidade celular, foi realizado o ensaio MTT, para a proliferação celular, foi realizado o ensaio “wound-healing” e, por fim, para avaliação in vivo, foi realizado o ensaio ZET. O uso de embriões de peixe-zebra permitiu obter dados toxicológicos em organismos complexos de maneira rápida e eficiente, permitindo concluir vários parâmetros ao mesmo tempo. Finalmente, foram comparados os resultados dos dois extratos de algas e as suas respetivas nanopartículas

Atitudes face à Violência entre Parceiros Íntimos e Aceitação-Rejeição pelo Par Amoroso em Estudantes Cabo-verdianos residentes em Portugal

This research sought to determine the prevalence of intimate partner violence, characterize attitudes toward violence, analyse relations between perceptions of intimate partner acceptance-rejection and practices of violence and examine relations between intimate partner acceptance-rejection and beliefs and attitudes toward intimate partner violence among Cape Verdean students that lives in Portugal. One hundred and sixteen participants, aged 15 to 25 years, from three professional schools, four secondary schools and one university, completed the Scale of Beliefs about Marital Violence, Marital Violence Inventory, Dating Violence Scales and Intimate Partner Acceptance-Rejection Questionnaire. Significant positive correlations were found between beliefs about marital violence, dating violence attitudes and intimate partner rejection. Regressions showed intimate partner rejection predicted marital violence beliefs and dating violence attitudes.O estudo procurou determinar a prevalência da violência na intimidade, caracterizar atitudes face à violência, analisar relações entre as percepções de aceitação pelo parceiro íntimo e a violência, averiguando relações entre a percepção de aceitação com as atitudes e crenças relativas à violência em alunos Cabo-verdianos residentes em Portugal. Cento e 16 participantes, entre os 15 e os 25 anos, oriundos de três escolas profissionais, quatro escolas secundárias e uma universidade, preencheram a Escala de Crenças sobre Violência Conjugal, Inventário de Violência Conjugal, Escalas de Violência no Namoro e Questionário de Aceitação-Rejeição pelo Par Amoroso. Encontraram-se correlações positivas significativas entre crenças, atitudes e rejeição pelo par amoroso. Regressões evidenciaram que a rejeição prediz crenças e atitudes relativas à violência