Payroll taxes and their effects on wages and employment stability

Mestrado em Economia Monetária e FinanceiraEsta dissertação explora a importância da taxa social única (TSU) e analisa a seguinte questão: Qual é o efeito nos salários e na estabilidade do emprego de uma redução da taxa social única? Desde 2009 que o Governo Português tem vindo a implementar cortes na TSU para alguns grupos específicos, no mercado de trabalho, com o objetivo de fomentar o emprego e os salários. Foram utilizados dados anuais entre 2009 e 2013 dos Quadros de Pessoal e dos registos da Segurança Social, este último com uma frequência mensal. Utilizando a metodologia das diferenças-nas-diferenças (DID), foram analisadas as recentes mudanças no mercado de trabalho Português e estimados efeitos positivos e significativos em termos de emprego. Contudo, existem pequenos impactos negativos nos salários, especialmente em trabalhadores com menos de 45 anos, mas também efeitos negativos na estabilidade do emprego com o uso deste tido de medidas.This dissertation explores the importance of the payroll tax (TSU) and tries to analyze que following question: What is the effect on wages and employment stability of a reduction in the payroll tax? Since 2009, Portuguese Government have been implementing cuts in the payroll tax for some specific groups, in the labor market, with the aim of boosting employment and wages. I used annual data between 2009 and 2013 from Quadros de Pessoal and Social Security records, the latter on a monthly basis. Using the difference-in-differences (DID) methodology, I analyzed these recent changes in the Portuguese labor market and I estimate positive and significant effects on employment. However, I found not only small negative impact on wages, especially in workers with less than 45 years old, but also negative effects on employment stability with the use of these kinds of measures

The optimum size of the portuguese public hospital

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 EconomicsIn a context of intensive structural reform, this paper estimates optimum bed-sizes for the Portuguese public hospitals. Considering costs and production data for the period 2003-2006, we estimate a production-theoretic quadratic cost-function, adjusted to better describe the underlying technology. Room for short-run scale-economies exploitation is found, but long-run scale-diseconomies are unambiguous. In light of these predictions and of an optimum around 233 fully-occupied beds, there is mixed evidence of potential gains from two hospital mergers and from one of the forthcoming constructions of public hospitals. The results are expected to contribute to shape the hospital network in a cost-efficient manner

Analysis of the efficiency of wind turbine gearboxes using the temperature variable

The aim of this paper is to evaluate how lubricant selection affects gearbox efficiency and overall energy production by analysing real data from wind farms, monitored and controlled by a Supervisory Control and Data Acquisition (SCADA system). The turbines analysed worked with two or more oil types for the same amount of hours, which allowed to establish relations between the active power curves and wind velocity; oil temperature inside gearboxes and wind velocity; and oil temperature inside gearboxes and active power production. The results of this study evidenced a direct relation between oil characteristics and energy efficiency i.e. gearboxes working with mineral oil perform better then gearboxes working with synthetic oils. Those differences can be significant in terms of active power production. Also, it was observed oil degradation as function of temperature increase, with changes on viscosity, which reveals that temperature behaviour along the active power curve is strongly related to oil' characteristics. (C) 2018 Elsevier Ltd. All rights reserved.Agência financiadora Portuguese Foundation for Science and Technology (FCT) PTDC/AAG-TEC/1710/2014 MONITOR project - Atlantic Area EAPA_333/2016 Portuguese Foundation for Science and Technology under the Portuguese Researchers' Programme 2014 IF/00286/2014/CP1234 Marie Sklodowska-Curie Actions of the European Union's H2020-MSCA-IF-EF-RI-2016/under REA - 748747info:eu-repo/semantics/publishedVersionhttp://creativecommons.org/licenses/by/4.0

Web usage mining for click fraud detection

Estágio realizado na AuditMark e orientado pelo Eng.º Pedro FortunaTese de mestrado integrado. Engenharia Informática e Computação. Faculdade de Engenharia. Universidade do Porto. 201

An empirical study over the industry differences in the profitability of the Azorean enterprises

Dissertação de Mestrado, Ciências Económicas e Empresariais (Finanças e Contabilidade), 19 de setembro de 2022, Universidade dos Açores.Nesta dissertação analisamos que fatores, específicos à empresa e macroeconómicos, explicam a rendibilidade das empresas nos Açores. Procura-se também examinar que fatores têm mais impacto em cada sector de atividade e se a rendibilidade média varia entre sectores. Desenvolve-se um modelo da rendibilidade baseado numa amostra de 516 empresas individuais, contendo 4160 observações, desde 1984 a 2019. As variáveis explicativas específicas à empresa neste modelo são o rácio de dívida, a dimensão, as oportunidades de crescimento, o risco, a rotação de ativos e a quota de mercado. Os fatores macroeconómicos são a taxa de crescimento do Produto Interno Bruto (PIB) e a taxa de inflação. Procede-se à estimação de regressões para as diferentes indústrias na amostra. Também estão incorporadas no modelo variáveis binárias associadas ao sector de atividade para estabelecer se a rendibilidade média varia entre sectores. Ao considerar a amostra completa, os resultados da regressão estimada indicam que existe um efeito negativo do rácio de dívida e da dimensão da empresa na rendibilidade. Por outro lado, os resultados sugerem que as oportunidades de crescimento, o risco, a rotação de ativos e a quota de mercado têm um efeito positivo na rendibilidade. Em relação às variáveis macroeconómicas, a taxa de inflação tem um efeito negativo, enquanto a taxa de crescimento do PIB tem um efeito positivo na rendibilidade. Os resultados sugerem que a rendibilidade de alguns sectores de atividade é afetada de forma diferente pelas variáveis explicativas incorporadas no modelo. No entanto, não se obteve resultados com significância estatística para todos os sectores. Além disso, os resultados indicam que a rendibilidade média é distinta entre diferentes sectores.ABSTRACT: This dissertation seeks to analyze what factors, firm specific and macroeconomic, explain the profitability of Azorean enterprises. Furthermore, it examines what factors are more impactful for each industry and if the profitability differs across industries. A model of firms’ profitability is developed based on a sample of 516 individual firms and 4160 observations, from 1984 to 2019. The firm specific explanatory variables for this model are leverage, size, growth opportunities, risk, asset turnover and market share. The macroeconomic variables are Gross Domestic Product (GDP) and the inflation rate. Additionally, regressions are estimated for the different industries contained in the sample. Moreover, the model incorporates a dummy variable associated with each industry to establish if the average profitability differs across industries. When considering the full sample, the estimated regression results implies that there is a negative effect of leverage and size on profitability. On the contrary, the results suggest that growth opportunities, risk, asset turnover and market share have a positive influence on profitability. As for the macroeconomic variables, the inflation rate has a negative effect, whereas GDP has a positive effect on profitability. The results suggest that some industries’ profitability is differently impacted by the explanatory variables incorporated in the model. However, the results did not have statistical significance for all the industries. Moreover, the results indicate that the average profitability is distinct across different industries

An approach to the Contextual Design methodology in the context of Information

Based on an operative definition of Information Science (IS) as a study of the mediation aspects of the phenomena: data, information, knowledge and message, and their implementation in the cultural domain, the potential of Contextual Design (CD) as a methodology for the development of optimized interfaces between information resources and users is analyzed. The goals are (i) to identify papers that address or make use of the CD methodology in databases related to IS; (ii) to describe the approaches to the concept of CD in those papers; (iii) to point out the potentials and limitations of this methodology. We draw an exploratory / descriptive study based on a systematic review and categorical analysis. Eight papers were retrieved, being a possible indicator of the reduced use of the methodology, in the IS area, the same is essentially practical. Although the limitation of non-involvement of users throughout the design process is pointed out, the methodology shows the ability to collect implicit information through user activities and the possibility of shared systematization of complex data. These characteristics make CD a potential value for the development of appropriate interfaces between information resources and their users

Marine energy prototype testing at Ria Formosa

Economic growth and increasing human demands are among the most important factors for growing world energy consumption. Energy is present in everything around us: it is a property of all objects and is essential to life. We find various forms of energy in the world around us. When plants grow, for example, they are converting sunlight energy into chemical energy in the form of carbohydrates and other compounds stored in your body (e.g. sugars). The form of energy that man uses most today is the chemical energy contained in fossil fuels, such as oil, coal and natural gas. About 80% of the energy we use comes from these sources. However, these sources are very polluting, since their use releases substances harmful to the environment and to public health. An example of this is the increased concentration of greenhouse gases such as carbon dioxide (CO2) in the atmosphere, which is a cause of climate change. In addition to pollutants, these sources of energy are non-renewable, which means that they are being consumed at a faster rate than is necessary for their production, so their availability is decreasing. Due to the increasing oil and natural gas prices, reduced fuel reserves and the requirement for reduced CO2 emissions to avert climate change, the use of alternative energy sources is both financially unavoidable and environmentally preferable (UN, 2015). Hence, generating renewable energy is nowadays one of the most relevant endeavours for research. Countries worldwide now recognise the need to incorporate renewable energy resources in their energy policy as an alternative to finite fossil fuel resources in order to achieve future energy security and to mitigate the effects of climate change induced by human activities. Today, renewable energy is now firmly entrenched as the world's fastest growing energy sector (IEA, 2017).info:eu-repo/semantics/publishedVersio

Single-Droplet Combustion of Jet A-1, Hydroprocessed Vegetable Oil, and Their Blends in a Drop-Tube Furnace

The environmental impact and the dependence upon fossil fuels in the aeronautical sector have promoted the demand for alternative and greener fuels. The implementation of alternative fuels is one of the main challenges for this sector in the near future. A possible short-term solution might be the blending of biofuels with jet fuel, which would allow for the use of greener fuels and a reduction in the greenhouse gases and pollutant emissions without significant changes in the existing fleets of the companies, with the purpose to develop a “drop-in” fuel. In this context, this work examines the combustion characteristics of single droplets of Jet A-1 (JF), hydroprocessed vegetable oil (NExBTL), and their mixtures in a drop-tube furnace (DTF). The objective of this work is to evaluate the influence of the mixture composition on the fuel characteristics. Droplets with diameters of 155 ± 5 μm, produced by a commercial droplet generator, were injected into the DTF, whose wall temperature and oxygen concentration were controlled. Experiments were conducted for three temperatures (900, 1000, and 1100 °C). The combustion of droplets was evaluated through the images obtained with a high-speed camera coupled with a high magnification lens and an edge detection algorithm. From the images allowed for the analysis of droplet combustion, data are reported for the temporal evolution of droplet sizes and burning rates. The results revealed that the mixtures followed the D2 law, except the mixture with 75% JF for a DTF wall temperature of 1100 °C. The 75% JF mixture did not follow the D2 law as a result of the occurrence of puffing and microexplosions, which enhanced the burning rates. Additionally, it was observed that the mixtures with a higher content of JF present brighter flames and higher burning rates.Fundação para a Ciência e a Tecnologiainfo:eu-repo/semantics/publishedVersio