Tax policy stance over the business cycle: evidence from Europe

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and EconomicsWe contribute to the literature addressing the cyclical behavior of tax policy. Most recent studies have relied on tax revenues and adjusted measures of tax collections to analyze this issue. We argue that such methodology is insufficient to characterize tax policy cyclicality, as tax revenues move endogenously with the business cycle. Consequently, this topic is revisited by making use of the policy instrument, tax rate, as opposed to the policy outcome, tax revenues. Using data for 13 European countries, we find that tax policy has mostly been a-cyclical over the last 30 years

Optimization of wireless power transmission systems

Mestrado em Engenharia Electrónica e TelecomunicaçõesNa área de transmissão de energia sem fios por radiofrequência, grande esforço tem sido dedicado ao desenvolvimento e estudo de formas de onda apropriadas para aumento da eficiência de conversão de energia de radiofrequência em energia DC, usada para alimentar os nossos dispositivos eletrónicos. Tal aumento de eficiência é obtido usando formas de onda que possuem uma elevada relação entre a potência de pico e a sua média. Os recetores destes sistemas são normalmente circuitos detetores de pico pelo que sinais de natureza multi-portadora são frequentemente usados para obter elevado Peak-to-Average Power Ratio (PAPR) permitindo ultrapassar a barreira de potencial dos díodos retificadores para potências inferiores, resultando num aumento de eficiência quando comparados com o cenário tradicional de uma única portadora. O aumento de eficiência de conversão traduz-se, por exemplo, num aumento da distância de comunicação de um sensor passivo. Com esta dissertação pretende-se efetuar um estudo ao nível de possíveis formas de onda a utilizar num transmissor de um sistema de transferência de energia sem fios por forma a aumentar a eficiência de conversão. Sinais inovadores como sendo multisenos harmonicamente espaçados e sinais de radar são pela primeira vez explorados nesta área e as suas vantagens/ desvantagens são reportadas. Verifica-se que aplicando a técnica de compressão de pulsos, tipicamente usada em sistemas de radares, a um sinal do tipo chirp resulta num sinal cujo PAPR pode ser controlado através de parâmetros inerentes ao sinal chirp utilizado e pode assumir um valor arbitrário. Por forma a testar sinais multiseno harmonicamente espaçados, o projeto de um conversor RF-DC de banda dupla é apresentado.Recently, in wireless power transmission field, many efforts were made in order to study and develop new waveforms that can boost the efficiency conversion of radio frequency energie into DC energie, which can be used to power up our electronics without cables. This efficiency boost is typically achieved by using waveforms that assumes a high peak power when compared with its average. The receivers are usualy simple peak detectors and then, signals with multicarrier nature are widely used to achieve high Peak-to-Average Power Ratio (PAPR) that enables us to activate a rectifying diode with less average power, when compared with the traditional single carrier case. This power conversion efficiency boost leads, for example, to an increase in the distance that a passive sensor can effectively communicate. This dissertation provides a study of several waveforms that can be used on a wireless power transmission system's transmitter that can actually further increase the power conversion efficiency of most RF to DC converters. Innovating signals such as harmonically spaced multisines and radar signals are exploited, for the first time, on wireless power transmission field and its advantages/disadvantages are reported. Moreover, if pulse compression technique is applied to a chirp signal, typically used on radar systems, we end up with a time domain waveform with a very high PAPR and it is possible to control its value adjusting some of the basic chirp signal parameters. In order to test harmonically spaced multisines, a dual band RF to DC converter is proposed and designed

Increase of protein content and production of lignocellulolytic enzymes by simultaneous solid-state fermentations of brewery, olive mill and winery wastes

Frequently, the agro-industrial wastes are used as animal feed, however many times these wastes have a poor nutritional quality, mainly they have a low protein content and their digestibility is hard. These disadvantages can be avoided by solid-state fermentation (SSF) of the wastes by filamentous fungi. Winery, brewery and olive mill wastes were used as solid substrates for the production of lignocellulolytic enzymes and to increase the crude protein content of agro-industrial wastes. After selection of the fungus in previously study, it was performed an experimental design to evaluate the benefits of using mixtures of wastes in different proportions as solid substrate in SSF by A. ibericus. The optimum substrate was a mixture of brewery spent grain and vine-shoot trimmings which achieved and increase the protein content (16.3 %), xylanase (89.33 U/g), cellulose (3.46 U/g) and -glucosidase (21.91 U/g) activities. Through this study, it was possible to conclude that the SSF by A. ibericus is a suitable biotechnology process to increase the nutritional quality of agro-industrial wastes and to produce value-added products as enzymes in the same low-cost process.info:eu-repo/semantics/publishedVersio

SYPEC: Desenvolvimento de uma aplicação Android para controlo e avaliação postural

Dissertação para obtenção do Grau de Mestre em Engenharia BiomédicaA evolução a que se assistiu desde a segunda metade do século XX até aos dias de hoje trouxe profundas alterações ao nosso cotidiano. As tarefas que outrora foram desempenhadas pelo Homem são hoje realizadas por máquinas e o estilo de vida tornou-se cada vez mais sedentário. Nesta sequência a posição de sentado tornou-se na posição mais adoptada pela população mundial, tanto num contexto profissional como de lazer. Associado a isso, estudos indicam que os factores como posturas inadequadas, fadiga muscular, e sobrecarga nas estruturas osteomioarticulares causadas pela adopção prolongada desta posição têm sido referenciados como de risco para o aparecimento de dor e lesão ao nível a região lombar. É neste contexto que se insere o projecto SYPEC (System for Posture Evaluation and Correction). O SYPEC é um projecto inovador nas áreas de ergonomia e biomecânica e, actualmente, utiliza uma cadeira de escritório convencional equipada com 8 almofadas de ar, cada uma delas ligadas a um compressor, uma electroválvula e um transdutor de pressão, que permitem medir e regular a pressão no interior das almofadas possibilitando a alteração de conformação das suas superfícies, para avaliação e correcção postural na posição de sentado. Nesta dissertação deu-se continuidade ao trabalho já desenvolvido implementando-se uma aplicação para controlo do protótipo, aquisição de dados e avaliação postural, através de um dispositivo móvel. Esta apresenta-se com uma solução integrada para avaliação postural e servirá de base aos actuais e futuros estudos no âmbito deste projecto. Conjuntamente foi desenvolvido um módulo de electrónica que permitiu dotar o SYPEC do protocolo de comunicação Bluetooth. Os resultados alcançados com a utilização desta aplicação são bastante promissores e possibilitaram a sua utilização noutros trabalhos do SYPEC em curso, tanto para aquisição de novos dados como para o estudo dos algoritmos de avaliação postural, em contexto real

Isolamento de Helicobacter pullorum de carne de frango: características de um patogénio emergente de origem alimentar

Objetivo: Este estudo apresenta a primeira descrição do isolamento de H. pullorum em amostras de carne de frango crua, revelando o importante papel da metodologia de Sequenciação Total do Genoma para a correta identificação e caracterização das estirpes isolada

The Anterior-Posterior Axis Emerges Respecting the Morphology of the Mouse Embryo that Changes and Aligns with the Uterus before Gastrulation

Background: When the anterior-posterior axis of the mouse embryo becomes explicit at gastrulation, it is almost perpendicular to the long uterine axis. This led to the belief that the uterus could play a key role in positioning this future body axis. Results: Here, we demonstrate that when the anterior-posterior axis first emerges it does not respect the axes of the uterus but, rather, the morphology of the embryo. Unexpectedly, the emerging anterior-posterior axis is initially aligned not with the long, but the short axis of the embryo. Then whether the embryo develops in vitro or in utero, the anterior-posterior axis becomes aligned with the long axis of embryo just prior to gastrulation. Of three mechanisms that could account for this apparent shift in anterior-posterior axis orientation–cell migration, spatial change of gene expression, or change in embryo shape–lineage tracing studies favor a shape change accompanied by restriction of the expression domain of anterior markers. This property of the embryo must be modulated by interactions with the uterus as ultimately the anterior-posterior and long axes of the embryo align with the left-right uterine axis. Conclusions: The emerging anterior-posterior axis relates to embryo morphology rather than that of the uterus. The apparent shift in its orientation to align with the long embryonic axis and with the uterus is associated with a change in embryo shape and a refinement of anterior gene expression pattern. This suggests an interdependence between anterior-posterior gene expression, the shape of the embryo, and the uterus

Potential of solid-state fermentation to enhance the nutritional value of oilseed cakes for poultry

[EN] The objective of this study was to evaluate the potential of solid-state fermentation (SSF) to enhance the nutritional value of oilseed cakes (OC) for poultry. To this end, firstly, we characterized the main nutrients and antinutritional factors in non-fermented OC and fermented OC, as well as in fermented and extracted OC, from where enzymatic extracts were recovered. The fermented and extracted OC represented the fermented residue obtained after SSF and extracted with distilled water. Secondly, we assessed the in vitro digestibility of dry matter (DM), organic matter (OM) and crude protein (CP) from these products using a poultry in vitro digestion model. The in vitro procedure used a two-stage sequential protocol simulating gastric digestion (proventriculus and gizzard - using pepsin in hydrochloric acid) and small intestinal digestion with pancreatin solution. Additionally, raw OC were supplemented with enzymatic concentrated extracts generated during SSF and their effect on nutrient digestibility was also evaluated. Solidstate fermentation exhibited a potential to reduce fiber fractions (except for lignin), decrease certain antinutritional factors, and enhance CP and mineral content in OC mixtures. However, this process concurrently diminished protein availability, through lower amino acid content, lower soluble protein, higher protein dispersibility and lower available lysine in the fermented product. The aqueous extractions led to the obtainment of a concentrated protein fraction with highly undigestible fibre. The likely effect of SSF on tannins and erucic acid content in OC should be further investigated, as SSF may not effectively reduce these antinutritional factors in the substrate, negatively affecting the overall nutritional quality of the final product. Solid-state fermented mixtures significantly increased the DM (by 12 %), OM (by 8 %), and CP (by 11 %) in vitro digestibility coefficients compared with non-fermented. Enzymatic supplementation did not statistically modify digestibility parameters. This study demonstrated that SSF is an effectiveProject funding was provided by the Portuguese Foundation for Science and Technology (FCT) , Portugal under the scope of the strategic funding of UIDB/BIO/04469/2020 (Braga, Portugal) and UIDB/04033/2020 (Vila Real, Portugal) units, and by national funds through FCT (PD/BD/135328/2017) , under the Doctoral Program "Agricultural Production Chains - from fork to farm" (PD/00122/2012) and from the European Social Funds and the Regional Operational Programme Norte 2020.Sousa, D.; Moset, V.; López-Luján, MDC.; Salgado, JM.; Dias, A.; Belo, I.; Pascual Amorós, JJ.... (2024). Potential of solid-state fermentation to enhance the nutritional value of oilseed cakes for poultry. Animal Feed Science and Technology. 316. https://doi.org/10.1016/j.anifeedsci.2024.11605631

Evaluation of biotechnological processing through solid-state fermentation of oilseed cakes on extracts bioactive potential

Oilseed cakes (OC) are natural sources of lignocellulosic biomass, produced every year in large amounts. In addition to their main applications as animal feed, plant or soil fertilizer, and compost, they present enormous potential for being used in biotechnological processes for the obtainment and extraction of valuable bioactive compounds. This work evaluated the effect of solid-state fermentation on the bioactive properties of extracts obtained from the bioprocessing of OC and evaluated the effect of solvents on the recovery of compounds with higher bioactive potential. A general decrease of EC50 values was observed for fermented extracts obtained using a mixture of water/methanol (1:1) as extraction solvent. A decrease in the minimum inhibitory concentration was observed for fermented water extracts compared to non-fermented. Additionally, growth inhibition of Listeria monocytogenes was observed when using aqueous methanolic fermented extracts. These extracts also exhibited a higher percentage of growth reduction against phytopathogenic fungi, and some extracts exhibited increased protection against genotoxic agents such as camptothecin and bisphenol A. It was demonstrated that bioprocessing of OC through SSF is an effective approach to obtaining valuable compounds with bioactive properties for use in the food, pharmaceutical or cosmetic industries.Open access funding provided by FCT|FCCN (b-on). The authors thank the Portuguese Foundation for Sci ence and Technology (FCT) under the scope of the strategic funding of UIDB/BIO/04469/2020 and UIDB/04033/2020 units. Daniel Sousa acknowledges the fnancial support pro vided by national funds through FCT(PD/BD/135328/2017), under the Doctoral Program “Agricultural Production Chains – from fork to farm” (PD/00122/2012) and from the European Social Funds and the Regional Operational Programme Norte 2020.info:eu-repo/semantics/publishedVersio