15 research outputs found

    Complexidade dos mercados financeiros - impacto social do resgate financeiro português

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    Não há memória, desde o 25 de Abril de 1974, de uma tão grave crise económica e financeira em Portugal. Antes da crise do subprime nos EUA em 2007, a economia portuguesa aparentava ser sustentavel . De forma inesperada, os cidadãos portugueses tiveram conhecimento que a dívida pública portuguesa era insustentável e apenas existia uma caminho a seguir, para evitar a colapso financeiro e económico. Solicitar um resgate financeiro externo àTroika. É neste sentido, que o presente estudo, vai incidir na relação de causalidade do contágio dos mercados financeiros internacionais com a crise em Portugal e analisar o impacto social das medidas de austeridade implementadas entre 2011 e 2014, na sequência do pedido de resgate financeiro

    A note on topological brane theories

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    We consider the theory of closed pp-branes propagating on (p+1)(p+1)-dimensional space-time manifolds. This theory has no local degrees of freedom. Here we study its canonical and BRST structures of the theory. In the case of locally flat backgrounds one can show that the pp-brane theory is related to another known topological field theory. In the general situation some equivalent actions can also be written for the topological pp-brane theory.Comment: 14 pages, latex, no figure

    From topological to parametrized field theory

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    It has been proposed to study the theory resulting from setting the gravitational constant to zero in the first order formalism for general relativity. In this letter we investigate this theory in the presence of matter fields, establish its equivalence with parametrized field theory on a flat background, and relate it to previous results in topological field theory (BF theory).Comment: 8 pages, latex, no figure

    Decomposition of Hilbert space in sets of coherent states

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    Within the generalized definition of coherent states as group orbits we study the orbit spaces and the orbit manifolds in the projective spaces constructed from linear representations. Invariant functions are suggested for arbitrary groups. The group SU(2) is studied in particular and the orbit spaces of its j=1/2 and j=1 representations completely determined. The orbits of SU(2) in CP^N can be either 2 or 3 dimensional, the first of them being either isomorphic to S^2 or to RP^2 and the latter being isomorphic to quotient spaces of RP^3. We end with a look from the same perspective to the quantum mechanical space of states in particle mechanics.Comment: revtex, 13 pages, 12 figure

    MAMMALS IN PORTUGAL : A data set of terrestrial, volant, and marine mammal occurrences in P ortugal

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    Mammals are threatened worldwide, with 26% of all species being includedin the IUCN threatened categories. This overall pattern is primarily associatedwith habitat loss or degradation, and human persecution for terrestrial mam-mals, and pollution, open net fishing, climate change, and prey depletion formarine mammals. Mammals play a key role in maintaining ecosystems func-tionality and resilience, and therefore information on their distribution is cru-cial to delineate and support conservation actions. MAMMALS INPORTUGAL is a publicly available data set compiling unpublishedgeoreferenced occurrence records of 92 terrestrial, volant, and marine mam-mals in mainland Portugal and archipelagos of the Azores and Madeira thatincludes 105,026 data entries between 1873 and 2021 (72% of the data occur-ring in 2000 and 2021). The methods used to collect the data were: live obser-vations/captures (43%), sign surveys (35%), camera trapping (16%),bioacoustics surveys (4%) and radiotracking, and inquiries that represent lessthan 1% of the records. The data set includes 13 types of records: (1) burrowsjsoil moundsjtunnel, (2) capture, (3) colony, (4) dead animaljhairjskullsjjaws, (5) genetic confirmation, (6) inquiries, (7) observation of live animal (8),observation in shelters, (9) photo trappingjvideo, (10) predators dietjpelletsjpine cones/nuts, (11) scatjtrackjditch, (12) telemetry and (13) vocalizationjecholocation. The spatial uncertainty of most records ranges between 0 and100 m (76%). Rodentia (n=31,573) has the highest number of records followedby Chiroptera (n=18,857), Carnivora (n=18,594), Lagomorpha (n=17,496),Cetartiodactyla (n=11,568) and Eulipotyphla (n=7008). The data setincludes records of species classified by the IUCN as threatened(e.g.,Oryctolagus cuniculus[n=12,159],Monachus monachus[n=1,512],andLynx pardinus[n=197]). We believe that this data set may stimulate thepublication of other European countries data sets that would certainly contrib-ute to ecology and conservation-related research, and therefore assisting onthe development of more accurate and tailored conservation managementstrategies for each species. There are no copyright restrictions; please cite thisdata paper when the data are used in publications.info:eu-repo/semantics/publishedVersio

    Entre consumos suntuários e comuns: a posse de objetos exóticos entre alguns habitantes do Porto (séculos XVI – XVII)

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    O estudo da documentação referente aos doadores da Misericórdia do Porto entre os séculos XVI e XVII, através dos objetos exóticos patentes nos respectivos testamentos e inven- tários – estes últimos provenientes de uma área que se estende de Macau ao Brasil –, permite discernir uma panóplia de objetos que mudaram a cultura material dos portuenses em contato com os territórios da expansão portuguesa. Um levantamento sistemático permitiu já rastrear, até o ano de 1699, 257 doadores, dos quais se apresentarão aqui apenas alguns, referentes a benfeitores que, não obstante possuírem bens móveis nesse âmbito, não são dados como tendo estado nos territórios de expansão transoceânica. Argumentar-se-á que essa circulação de objetos não foi exclusiva das elites nobiliárquicas, nem dos grandes centros urbanos, pelo que a sua difusão atingiu maiores proporções do que aquelas que a historiografia tem admitido até agora. A cidade em observação neste estudo – o Porto dos séculos XVI e XVII – estava longe de ser das maiores da Europa nesse período, quer em dimensão territorial, quer em efetivos populacionais, embora se situasse numa região de demografia pujante, que canalizou os seus excedentes desde cedo para a emigração interna e externa – o Entre Douro e Minho. Como teremos ocasião de verificar, fidalgos e nobres possuíam bens exóticos, mas estes encontravam-se também entre mercadores e até artesãos mais desafogados. Por outro lado, nem todos os objetos provenientes dos espaços da expansão transoceânica devem ser conotados com bens de luxo.The study of the sources referring to the donors of the Misericórdia of the city of Porto during the sixteenth and seventeenth centuries has revealed the presence of numerous exotic objects in their last wills and inventories. A survey has traced 257 donors until 1699, some of them having died in an area that extends from Macao to Brazil. Only a small number of cases shall be presented here, pertaining to benefactors who, in spite of owning objects of transoceanic origin, seem to have remained in mainland Portugal. It shall be argued that the circulation of objects has not been exclusive either to the elites of the nobility or to the large urban centres, their diffusion having been on a larger scale than what has been admitted until now. The city under scrutiny in this study – Porto during the sixteenth and seventeenth centuries – was not one of the bigger cities in this period, either in what respects to size or population, although it was located in an area of flourishing demography, that channelled its surplus population early on to internal and external emigration. Fidalgos and noblemen owned exotic goods, but these were to be found among merchants and even well-to-do artisans. On the other hand, not all objects originating from the areas of transoceanic expansion should be considered as luxury goods.info:eu-repo/semantics/publishedVersio

    Mammals in Portugal: a data set of terrestrial, volant, and marine mammal occurrences in Portugal

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    Mammals are threatened worldwide, with ~26% of all species being included in the IUCN threatened categories. This overall pattern is primarily associated with habitat loss or degradation, and human persecution for terrestrial mammals, and pollution, open net fishing, climate change, and prey depletion for marine mammals. Mammals play a key role in maintaining ecosystems functionality and resilience, and therefore information on their distribution is crucial to delineate and support conservation actions. MAMMALS IN PORTUGAL is a publicly available data set compiling unpublished georeferenced occurrence records of 92 terrestrial, volant, and marine mammals in mainland Portugal and archipelagos of the Azores and Madeira that includes 105,026 data entries between 1873 and 2021 (72% of the data occurring in 2000 and 2021). The methods used to collect the data were: live observations/captures (43%), sign surveys (35%), camera trapping (16%), bioacoustics surveys (4%) and radiotracking, and inquiries that represent less than 1% of the records. The data set includes 13 types of records: (1) burrows | soil mounds | tunnel, (2) capture, (3) colony, (4) dead animal | hair | skulls | jaws, (5) genetic confirmation, (6) inquiries, (7) observation of live animal (8), observation in shelters, (9) photo trapping | video, (10) predators diet | pellets | pine cones/nuts, (11) scat | track | ditch, (12) telemetry and (13) vocalization | echolocation. The spatial uncertainty of most records ranges between 0 and 100 m (76%). Rodentia (n =31,573) has the highest number of records followed by Chiroptera (n = 18,857), Carnivora (n = 18,594), Lagomorpha (n = 17,496), Cetartiodactyla (n = 11,568) and Eulipotyphla (n = 7008). The data set includes records of species classified by the IUCN as threatened (e.g., Oryctolagus cuniculus [n = 12,159], Monachus monachus [n = 1,512], and Lynx pardinus [n = 197]). We believe that this data set may stimulate the publication of other European countries data sets that would certainly contribute to ecology and conservation-related research, and therefore assisting on the development of more accurate and tailored conservation management strategies for each species. There are no copyright restrictions; please cite this data paper when the data are used in publications

    From quantum field theory to quantum mechanics

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    The purpose of this article is to construct an explicit relation between the field operators in Quantum Field Theory and the relevant operators in Quantum Mechanics for a system of N identical particles, which are the symmetrised functions of the canonical operators of position and momentum, thus providing a clear relation between Quantum Field Theory and Quantum Mechanics. This is achieved in the context of the non-interacting Klein–Gordon field. Though this procedure may not be extendible to interacting field theories, since it relies crucially on particle number conservation, we find it nevertheless important that such an explicit relation can be found at least for free fields. It also comes out that whatever statistics the field operators obey (either commuting or anticommuting), the position and momentum operators obey commutation relations. The construction of position operators raises the issue of localizability of particles in Relativistic Quantum Mechanics, as the position operator for a single particle turns out to be the Newton–Wigner position operator. We make some clarifications on the interpretation of Newton–Wigner localized states and we consider the transformation properties of position operators under Lorentz transformations, showing that they do not transform as tensors, rather in a manner that preserves the canonical commutation relations. From a complex Klein–Gordon field, position and momentum operators can be constructed for both particles and antiparticles
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