544 research outputs found
The laffer curve: an empirical estimation for eurozone member countries
Códigos do JEL: C23, E62, H21./The current economic and sovereign crisis in the Eurozone led some European governments, due mainly to outside impositions (of the IMF, European Commission, and the ECB, the troika), to increases the tax rates, with the goal of boosting tax revenues, and in that way to decrease excessive deficits, and to fight high public debt, which most countries of the Eurozone, in particular Southern Countries, face. Were these decisions the most correct? What is the relationship between tax rates and tax revenues? What is the tax rate that maximizes the revenue? In the economic literature we find in the concept of the Laffer Curve the answer for the previous questions. Using panel-data, observed between 1995 and 2011 (for direct taxes) and 2000 and 2011 (for indirect taxes), we will estimate Laffer Curves for the Eurozone countries, either for the Eurozone as a whole and also for each individual Eurozone member country. We chose the three taxes that contribute the most to the state revenue, and they are the value added tax (VAT), as an indirect tax; the corporate income tax, and the household income tax. We can conclude for the existence of a Laffer Curve in the Eurozone for VAT and for the individual income tax, but in case of the corporate income tax, we come to the opposite conclusion. In the case of Portugal the optimal tax rate for the individual income tax is 49% and for the corporate income tax is 30%.A grave crise económica e orçamental que tem vindo a assolar os países da Zona Euro levou
alguns governos, maioritariamente devido a imposições externas (FMI, Comissão Europeia e
BCE, a troika), a aumentar as taxas de imposto, com o objetivo de aumentar a receita fiscal
para evitar a ocorrência de défices excessivos, que se têm verificado continuadamente, e dessa
forma combater a elevada divida pública que caracteriza uma parte dos países da Zona Euro
(principalmente os Países do Sul). Terá sido esta a decisão mais correta? Qual a relação entre a
taxa de um dado imposto e a sua receita? Qual é a taxa de imposto que maximiza a receita desse
imposto? A teoria económica encontra na Curva de Laffer a resposta a estas perguntas. Através
de estimação econométrica com dados em painel, compreendidos entre 1995-2011 (impostos
diretos) e 2000-2011 (imposto indireto), iremos estimar a Curva de Laffer para a Zona Euro,
evidenciando possíveis diferenças entre países. Para tal escolhemos os três impostos que mais
contribuem para as receitas do estado - o Imposto sobre o Valor Acrescentado (IVA); o Imposto
sobre o Rendimento das Pessoas Coletivas (IRC) e, por último, o Imposto sobre o Rendimento
das Pessoas Singulares (IRS). Através das nossas estimações concluímos que existe evidência
da Curva de Laffer para a Zona Euro para o IVA e para o IRS, enquanto que para o IRC,
chegamos à conclusão inversa. Para Portugal a taxa ótima para o IRC é de 30% e para o IRS é
de 49%
The influence of gut microbiota in cardiovascular diseases - a brief review
Lately, the gut microbiota has emerged as an important mediator of the development and the outcomes of certain diseases. It's well known that the gut microbiota plays an important role in maintaining human health. Still far from being completely understood and analyzed is the complexity of this ecosystem, although a close relationship between the gut microbiota and cardiovascular diseases (CVD) has been established. A loss of diversity in the microbiota will lead to physiological changes, which can improve inflammatory or infection states like atherosclerosis and hypertension, the basic pathological process of CVD. Targeting the gut microbiota and its metabolites are new and promising strategies for the treatment and prognosis of CVD.info:eu-repo/semantics/publishedVersio
Commentary: Theileria Parasites Secrete a Prolyl Isomerase to Maintain Host Leukocyte Transformation
Free PMC Article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5934426/pdf/fmed-05-00120.pdfA commentary on: Theileria Parasites Secrete a Prolyl Isomerase to Maintain Host Leukocyte Transformation
by Marsolier J, Perichon M, DeBarry JD, Villoutreix BO, Chluba J, Lopez T, et al. Nature (2015) 520:378–82. doi: 10.1038/nature14044The genus Theileria comprises apicomplexan parasites that are tick-transmitted and infect ruminants with important trade and industry impact in endemic countries. Infectious agents build up elaborate machinery to work together by means of host cell pathways and takeover their genetic and epigenetic mechanisms to modify phenotypic status of host cells. Among the Apicomplexa phylum encompassing obligate intracellular parasites, the only genus that introduces its DNA into mammalian host cells is Theileria, which is known to cause veterinary and human diseases. Various species, including Theileria parva and Theileria annulata, infect leukocytes causing alterations in their phenotypes that are common with several cancers, remarkably immortalization, hyperproliferation, and spreading. (...)info:eu-repo/semantics/publishedVersio
Resistance to β-lactams in Bacteria Isolated from Different Types of Portuguese Cheese
The purpose of this study was to investigate the presence of β-lactam-resistant bacteria in six different types of Portuguese cheese. The numbers of ampicillin resistant (AMPr) bacteria varied from 4.7 × 102 to 1.5 × 107 CFU/g. Within 172 randomly selected β-lactam-resistant bacteria, 44 resistant phenotypes were found and 31.4% were multidrug resistant. The majority (85%) of the isolates identified belonged to the Enterobacteriaceae family. The presence of the blaTEM gene was detected in 80.9% of the tested isolates. The results suggest that without thermal processing of the milk and good hygienic practices, cheese may act as a vehicle of transfer of β-lactam-resistant bacteria to the gastrointestinal tract of consumers
Análise de sensibilidade e risco no resgate da concessão e gestão da rede de distribuição de energia numa autarquia
Tese de Mestrado Integrado. Engenharia Electrotécnica e de Computadores. Área de Especialização de Energia. Faculdade de Engenharia. Universidade do Porto. 201
Gas-phase conversion of glycerol to allyl alcohol over vanadium-supported zeolite beta
Vanadium oxide supported beta zeolite (Si/Al=25, 4% V) was used as catalyst for the one-pass gas-phase conversion of glycerol to allyl alcohol without any external reductant. The catalytic data strongly suggest a consecutive reactions path involving the dehydration to acrolein over the zeolite acid sites followed by a selective reduction through a hydrogen-transfer reaction. Acidity is expected to play a major role in what concerns the selectivity, as demonstrated by the catalytic results obtained by the impregnation of vanadium on a previously Cs-exchanged sample that achieved ca. 30% selectivity to allyl alcohol at ca. 20% glycerol conversion.info:eu-repo/semantics/publishedVersio
Desenvolvimento de um sistema de controlo e monitorização residencial através de tecnologias associadas à Internet das Coisas
Dissertação de mestrado integrado em Engenharia Eletrónica Industrial e ComputadoresA presente dissertação visa o desenvolvimento de um sistema de controlo e monitorização
residencial baseado numa plataforma IoT (Internet of Things). O sistema assenta numa arquitetura de
redes sem fios híbrida que integra vários dispositivos Bluetooth Low Energy (BLE) e/ou Wi-Fi com
diferentes funções, como nós sensores, nós atuadores e um hub/gateway. A comunicação entre
entidades da plataforma é assegurada pelo protocolo MQTT (Message Queuing Telemetry Transport)
através do modelo publish/subscribe.
A realização deste projeto assenta em vários aspetos essenciais, dos quais se destacam:
especificação da arquitetura enquadrada com as necessidades e funcionalidades desejadas; seleção e
programação de dispositivos para controlo e monitorização de equipamentos da smart home;
implementação de base de dados local para o armazenamento de dados relevantes; implementação de
gateway (BLE-Wi-Fi) de forma a permitir a comunicação entres dispositivos com diferentes protocolos;
desenvolvimento de aplicação Android para controlar e monitorizar em tempo real os equipamentos
através de uma interface gráfica.
Para a validação experimental foram realizados diversos testes para verificar o atraso e a fiabilidade
das comunicações num ambiente habitacional. Foi possível verificar que não ocorreram perdas de
pacotes e que o atraso máximo em todos os casos foi inferior a 1 segundo, permitindo que o sistema
reaja rapidamente a alterações do valor de corrente, evitando que o disjuntor na habitação atue e
possibilitando que o utilizador receba/envie dados de forma quase instantânea. A aplicação Android
desenvolvida funcionou como pretendido, enviando e recebendo dados através da rede com o protocolo
MQTT, e os sensores utilizados funcionaram com a precisão adequada. Um sistema de carregamento
de veículos elétricos já existente foi integrado com sucesso no sistema e foi desenvolvido um protótipo
de uma tomada elétrica inteligente que calcula os valores eficazes de tensão e corrente e controla o
estado de operação do equipamento que a ela estiver ligado. O desenvolvimento do sistema teve em
conta a utilização de software/firmware de utilização livre e hardware de baixo custo. Conforme validado
com os resultados experimentais, os objetivos estabelecidos inicialmente foram cumpridos.This dissertation aims the development of a home control and monitoring system based on an IoT
(Internet of Things) platform. The system is based on a hybrid wireless architecture that integrates
multiple Bluetooth Low Energy (BLE) and/or Wi-Fi devices with different functions such as sensor nodes,
actuator nodes and a hub/gateway. Communication between platform entities is ensured by the MQTT
(Message Queuing Telemetry Transport) protocol through the publish/subscribe model.
For the realization of this project it was essential: to specify an architecture that met the needs and
desired functionality; select and program devices to efficiently control and monitor smart home
equipment; implement a local database for storing relevant data; implement a gateway (BLE-Wi-Fi) to
allow communication between devices with different protocols; and develop an Android application to
control and monitor equipment in real time through a graphical interface.
Experimental tests were performed to verify the delay and reliability of communications in a
residential environment. No packet loss occurred and the maximum delay in all cases was less than 1
second, allowing the system to react quickly to changes in current value, preventing the circuit breaker in
the home from tripping and allowing the user to receive/send data in a timely manner. The Android
application worked as intended by sending and receiving data over the network using the MQTT protocol
and the sensors worked with the proper accuracy. An existing electric vehicle charging system has been
successfully integrated into the system and a prototype smart electrical socket has been developed to
measure the current and voltage and control the operating state of the connected equipment (ON/OFF).
The development of the system considered the use of free software/firmware and low-cost hardware. As
validated with the experimental results, the initially established objectives were met, allowing even new
approaches
Segurança nacional e estratégias energéticas de Portugal e de Espanha
A “Segurança Nacional e as Estratégias Energéticas de Portugal e Espanha” lida
com um dos temas de maior relevância para a Segurança de ambos os países ibéricos:
a questão da energia.
O primeiro capítulo leva o leitor para o quadro internacional da energia e os riscos e
as ameaças que afectam a segurança energética em termos globais e europeus. O segundo
capítulo lida com as vulnerabilidades e potencialidades da Península Ibérica e com as
vantagens que uma relação mais íntima e uma cooperação mais activa com o Magreb
podem dar à segurança energética de Portugal e de Espanha. O terceiro capítulo trata
do papel das energias alternativas, em especial da energia nuclear, como resposta às
questões dos delimitados recursos energéticos e da carbonização do planeta. O último
capítulo analisa a relação entre as novas ameaças à segurança e a questão energética,
principalmente pela possibilidade de grupos terroristas utilizarem armas de teor químico,
biológico ou radioactivo‑nuclear
Impact Analysis of Managerial Decisions on the Overall Performance of a Public Transport Operator: The Case of STCP
AbstractThis paper presents a case study from Porto-based public transport operator Sociedade de Transportes Colectivos do Porto (STCP) to closer investigate the relation between managerial decisions and economic indicators in public transport, such as efficiency and effectiveness. By means of Data Envelopment Analysis (DEA) the company's performance results between 1946 and 2004 are analyzed. The second part of the analysis serves to explore the managerial history of STCP and to point out main decisions, policies or other decisive factors in the framework of the company's performance. Our approach aims at identifying the magnitude of these decisions within the operational framework and their time-lags. The analysis has shown that certain managerial decisions directly influence the operational activity in the following years and considerably affect the overall performance of the services provided. The decisions are mostly linked to an increase of social benefits and privileges, political and social environment, the implementation of the single agent policy and operational leasing. Another essential conclusion is the identification of a certain time-frame of such influence. Results show the existence of time-lags between decisions and performance, usually representing medium term periods from 2 to 4 years. The results might be translated into policy recommendations, e.g. for setting up the regulatory framework that achieves a systems best performance
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