Estado em crise: breve análise, vista sob a perspectiva

O Estado está em constante mutação. No futuro,tanto poderá ser mantido, ainda que reformulado, em face daflexibilização do conceito de soberania, como desaparecer,absorvido por entes de caráter supranacional. Aglobalização, insere-se nesse contexto. Com o Brasil nãopoderá ser diferente, devendo avançar a integração sócioeconômica no Mercosul, ou ceder espaço à formação da Alca.De qualquer sorte, pelo exaurimento do Neoliberalismo,impõe-se a formação de um novo Estado, de resgate dadimensão humana: o Estado Neosocial

Resultados da primeira campanha de escavação na Anta dos Currais do Galhordas (Castelo de Vide - Centro Leste de Portugal) : breve síntese

A Anta dos Currais do Galhordas é um monumento megalítico composto por câmara poligonal, corredore mamoa. A primeira campanha de escavação permitiu identificar vários aspectos relacionados com a sua arquitectura; permitiu igualmente a recolha de diversos artefactos, nomeadamente em pedra lascada (raros) e em pedra polida, placas de xisto (uma lisa e uma gravada) e vasos cerâmicos. No âmbito do estudo destes últimos procedeu-se à análise do conteúdo de três recipientes através de cromatografia gasosa com detecção por massa.Alguns dos recipientes cerâmicos exumados relacionam a anta com uma cronologia que deverá estar próxima da transição do IV para o III milénio cal. BC. Não se exclui, no entanto, a possibilidade da sua construção ser anterior a esta fase, o que terá de ser verificado através de datações absolutas pelo radiocarbono. Outros recipientes sugerem reutilizações mais tardias (Idade do Bronze).Anta dos Currais do Galhordas is a megalithic passage tomb complete with mound and a chamber of polygonal plan. The first season of excavation has identified several of the building techniques that were employed in its construction; and recovered associated artefacts such as flaked (rare) and polished stone-tools, engraved and non-engraved slate plaques, and pottery. Three vessels have been sent for content analysis by gas chromatography coupled to mass spectrometry. Absolute dating is not yet available, but some of the pottery suggests that the monument was built between the end of the 4th millennium cal. BC and the beginning of the 3rd millennium cal. BC. However, an earlier chronology is also accepted. Other vases document more recent burials (Bronze age)

Robot formations: robots allocation and leader-follower pairs

In this paper we focus on the problem of assigning robots to places in a desired formation, considering random initial locations of the robots. Since we use a leader-follower strategy, we also address the task of choosing the leader to each follower. The result is a formation matrix that describes the relation between the robots and the desired formation shape. Simple algorithms are defined, that are based on the minimization of the distances of robots to places in the formation. All these algorithms are implemented in a decentralized way. We assume that communication is possible, but the requirements are of very-low bandwidth.Fundação para a Ciência e a Tecnologia (FCT

Attractor dynamics approach to formation control : theory and application

In this paper we show how non-linear attractor dynamics can be used as a framework to control teams of autonomous mobile robots that should navigate according to a predefined geometric formation. The environment does not need to be known a priori and may change over time. Implicit to the control architecture are some important features such as establishing and moving the formation, split and join of formations (when necessary to avoid obstacles). Formations are defined by a formation matrix. By manipulating this formation matrix it is also possible to switch formations at run time. Examples of simulation results and implementations with real robots (teams of Khepera robots and medium size mobile robots), demonstrate formation switch, static and dynamic obstacle avoidance and split and join formations without the need for any explicit coordination scheme. Robustness against environmental perturbations is intrinsically achieved because the behaviour of each robot is generated as a time series of asymptotically stable states, which contribute to the asymptotic stability of the overall control system.This work was supported through COOP-DYN (POSI/SRI/38051/2001), financed by the Portuguese Foundation for Science and Technology (FCT) and project fp6-IST2 EU-project JAST-Joint Action Science and Technology (project number 003747). We thank Miguel Vaz and Nzoji Hipolito for their help in the implementations with real robots. We would like also to thank the anonymous reviewers for their insightful comments which helped improving the paper

Sustainable Approach to Weed Management: The Role of Precision Weed Management

In the last few decades, the increase in the world’s population has created a need to produce more food, generating, consequently, greater pressure on agricultural production. In addition, problems related to climate change, water scarcity or decreasing amounts of arable land have serious implications for farming sustainability. Weeds can affect food production in agricultural systems, decreasing the product quality and productivity due to the competition for natural resources. On the other hand, weeds can also be considered to be valuable indicators of biodiversity because of their role in providing ecosystem services. In this sense, there is a need to carry out an effective and sustainable weed management process, integrating the various control methods (i.e., cultural, mechanical and chemical) in a harmonious way, without harming the entire agrarian ecosystem. Thus, intensive mechanization and herbicide use should be avoided. Herbicide resistance in some weed biotypes is a major concern today and must be tackled. On the other hand, the recent development of weed control technologies can promote higher levels of food production, lower the amount of inputs needed and reduce environmental damage, invariably bringing us closer to more sustainable agricultural systems. In this paper, we review the most common conventional and non-conventional weed control strategies from a sustainability perspective, highlighting the application of the precision and automated weed control technologies associated with precision weed management (PWM).info:eu-repo/semantics/publishedVersio

Sustainable Approach to Weed Management: The Role of Precision Weed Management

In the last few decades, the increase in the world’s population has created a need to produce more food, generating, consequently, greater pressure on agricultural production. In addition, problems related to climate change, water scarcity or decreasing amounts of arable land have serious implications for farming sustainability. Weeds can affect food production in agricultural systems, decreasing the product quality and productivity due to the competition for natural resources. On the other hand, weeds can also be considered to be valuable indicators of biodiversity because of their role in providing ecosystem services. In this sense, there is a need to carry out an effective and sustainable weed management process, integrating the various control methods (i.e., cultural, mechanical and chemical) in a harmonious way, without harming the entire agrarian ecosystem. Thus, intensive mechanization and herbicide use should be avoided. Herbicide resistance in some weed biotypes is a major concern today and must be tackled. On the other hand, the recent development of weed control technologies can promote higher levels of food production, lower the amount of inputs needed and reduce environmental damage, invariably bringing us closer to more sustainable agricultural systems. In this paper, we review the most common conventional and non-conventional weed control strategies from a sustainability perspective, highlighting the application of the precision and automated weed control technologies associated with precision weed management (PWM).info:eu-repo/semantics/publishedVersio

New data on the stratigraphy and chronology of the prehistoric site of Prazo (Freixo de Numão)

O sítio arqueológico do Prazo situa-se na freguesia de Freixo de Numão (Vila Nova deFoz Côa, Nordeste de Portugal). Após a sua descoberta, no início dos anos 80, o Prazo foialvo de várias campanhas de escavação orientadas para o estudo da villa romana e dos vestígiosmedievais existentes no local. Em 1996, os trabalhos de campo puseram a descobertoníveis datados do Neolítico Antigo. Entre 1997 e 2001, as escavações realizadas centraramsena análise destes níveis pré-históricos, revelando a existência de uma espessa sequênciaestratigráfica que, para além de conservar depósitos residuais plistocénicos, incluía igualmentesedimentos atribuíveis a grande parte do Holocénico antigo e médio. Este artigo pretendeapresentar a geoarqueologia e a cronologia da sequência pré-histórica do Prazo, quese organiza essencialmente em três conjuntos: um conjunto do Plistocénico superior (conjuntoPS), constituído por depósitos de vertente, e contendo um registo arqueológico (artefactoslíticos e estruturas antrópicas) datado provisoriamente do Paleolítico superior; umconjunto atribuído ao Holocénico antigo e médio (conjunto HA), igualmente composto por sedimentos de vertente e que forneceu elementos arqueológicos do Epipaleolítico/Mesolí-tico e do Neolítico Antigo; um conjunto do Holocénico recente (conjunto HR), correspondenteàs ocupações romanas e medievais do local. Neste texto discutem-se igualmente asdatações radiométricas disponíveis. Estes dados, embora preliminares, visam esclarecer questõesrelacionadas com a evolução ambiental do local e com as estratégias da sua ocupaçãodurante a Pré-história.The Prazo archaeological site is located near Freixo de Numão (Vila Nova deFoz Côa, north-eastern Portugal). The site, discovered in the early 80s, initially revealed asignificant historical record, having been a Roman villawhose occupation continued throughpart of the Middle Ages. In 1996, fieldwork there uncovered Neolithic layers. They were excavatedfrom 1997 to 2001, revealing also the existence of a pre-Neolithic occupation. Thispaper presents the geoarchaeology and chronology of the prehistoric succession of Prazo,which is arranged as follows: an upper Pleistocene complex formed of slope waste sediments,featuring upper Palaeolithic finds and structures; an early to mid Holocene succession, alsocomposed from slope waste deposits, containing Epipalaeolithic/Mesolithic and EarlyNeolithic archaeological assemblages and features; and an upper Holocene complex, correspondingto occupations in the Roman and Middle Ages. The available data deriving fromthe geoarchaeological survey at the site and from an extensive range of radiocarbon dates are presented as part of a preliminary discussion of the environmental evolution and thesettlement strategies at the site

A Estação Paleolítica do Cerro (Vila Nova de Gaia, Noroeste de Portugal): caracterização preliminar dos utensílios com configuração bifacial

A estação paleolítica do Cerro foi descoberta em 1988. Entre 1989 e 1992 realizaram-se três campanhas de escavação que permitiram recolher um importante conjunto de artefactos líticos talhados a partir de seixos rolados de quartzito, atribuíveis ao Paleolítico Inferior. Do ponto de vista geoarqueológico, estes artefactos associam-se a coluviões, que se sobrepõem a uma formação marinha implantada a cerca de 22 m n.m.a.m. O estudo das peças com configuração bifacial (em que também se incluem as parcialmente bifaciais e as unifaciais) revelou a existência de duas cadeias operatórias, globalmente expeditas, que visaram, sobretudo, a criação de utensílios com extremidade distal apontada. Estas cadeias operatórias mais do que se ligarem a opções de natureza morfológica parecem antes constituir uma resposta aos constrangimentos impostos pela volumetria dos suportes utilizados, visando a sua eventual adequação a distintas funcionalidades.The Palaeolithic site of Cerro was discovered in 1988. Between 1989 and 1992 three excavation seasons were carried out, which allowed collecting an important set of macrolithic stone tools most of them made of quartzite pebbles, possibly dating from the Lower Palaeolithic. From a geoarchaeological point of view, these stone tools were associated with colluvial deposits which overlay a marine formation c. 22 m a.s.l. The study of the bifacial shaped tools (including the parcial bifacial shaped and the unifacial tools) allowed the identification of two chaînes operatoires, basically expedite, oriented towards the production of pointed tools. These chaînes operatoires do not seem to be linked to morphological options but instead they may be a response to the constraints imposed by the volumetry of the blanks, possibly adapting them to distinct funcionalities

Study on debt maturity of portuguese smes 2009-2011

Classificação: G30, G32The purpose of this empirical work is to understand the reasoning behind debt maturity choices from Portuguese SMEs and to see if those choices are made based on the existent debt maturity theories proposed by the finance literature. We consider an important period for the Portuguese economy where the country was starting to feel the effects of the 2008 financial crisis and where companies, especially small ones, had to make smart long time decisions about their debt levels and maturities in order to survive future tough austerity policies. With a sample of 2,000 Portuguese SMEs for the time period between 2009 and 2011, using panel data methodology, we run two sample mean comparison t-tests as well as fixed effects model regression in order to study the debt maturity determinants within SMEs. An increasing trend was found on average debt maturity during the three years on analysis. Our study showed partially consistent results with Diamond´s (1991) theory where intermediate quality firms choose to issue more long term debt while high quality firms tend to issue more short term debt. Smaller firms (those more affected by asymmetric information) tend to use debt of shorter maturities. Furthermore, we find evidence supporting the clientele argument where firms affected by higher tax rates have longer debt maturities. Finally, firms with more growth opportunities are using more short term debt.O propósito deste estudo empírico é procurar entender as razões das escolhas das PME Portuguesas relativamente às maturidades das respetivas dívidas e verificar se elas encontram eco nas teorias sobre maturidade da dívida propostas pela literatura financeira. Estudámos um período da economia Portuguesa - período do início das repercussões da crise financeira de 2008 – em que as empresas, especialmente PME, foram forçadas a tomar penosas decisões de longo prazo sobre o nível e maturidade das respetivas dívidas, para conseguirem sobreviver à política de austeridade que se adivinhava. Com uma amostra de 2,000 PME – anos de 2009 a 2011, utilizámos a metodologia em dados de painel com comparações de médias baseadas em testes t e o modelo de efeitos fixos para as regressões, para verificar quais os fatores determinantes explicativos das diferentes maturidades da dívida dessas PME. Encontrámos uma tendência de crescimento na maturidade da dívida média nos anos em análise. Os resultados são parcialmente consistentes com a teoria de Diamond (1991), segundo a qual empresas de qualidade média tendem a contrair mais dívida de longo prazo, enquanto empresas de baixa e alta qualidade, tendem a contrair mais dívida de curto prazo. Empresas de menor dimensão (normalmente mais afetadas por informação assimétrica) tendem a utilizar mais dívida a curto prazo. Além disso, detetámos provas consistentes com o “clientele argument”, segundo o qual empresas afetadas por taxas de imposto mais altas, contraem dívida com prazos mais longos. Finalmente, empresas com mais oportunidades de crescimento tendem a utilizar mais dívida a curto prazo