107 research outputs found
Területfejlesztés vagy iparpolitika?: A francia versenyképességi pólus program tapasztalatai
A tanulmány felvázolja a területfejlesztési és a verseny-, illetve iparpolitikának a metszetében elhelyezkedő francia versenyképességi pólusok kialakulásának előzményeit, elméleti hátterét, és az alig egy évtizedes
múltra visszatekintő gyakorlati tapasztalatok összegzésére vállalkozik. A versenyképességi pólusok az innovációs szereplők hálózatos kapcsolataira épülnek, fejlődésüket a szereplők közti együttműködés minősége alakítja. Miközben a teljesítmény-szemléletű politikák a legdinamikusabban fejlődő régiókra összpontosítanak az ország európai és globális pozícióját szem előtt tartva, és a pólusok esetében is a legígéretesebb csúcsipari ágazatok támogatását szorgalmazzák, a közel fél évszázados múltú egyenlősítő célzatú területfejlesztési politikák céljai a pólusok nagy számával és a hagyományos, érettebb ágazatok támogatásával realizálódnak. A kettős célkitűzés egyidejűleg a pólusprogram esetében is nehezen teljesíthető, de mindmáig jelen van az ország jövőjét meghatározó területpolitikai vitákban
Expansão para oeste do peixe-gato-europeu Silurus glanis no rio Douro (Portugal)
The current study reports the first occurrence and the spread of the European catfish Silurus glanis (Family: Siluridae) in the
Portuguese section of the Douro River, suggesting a potential expansion of its distribution in Portugal either via westward dispersal across international rivers and/or human-assisted introductions into new reservoirs and drainages. The European catfish
has unique features (e.g., opportunistic predator, hunting, and aggregation behaviour) that make it highly suitable for establishing self-sustaining populations in new areas and likely contribute to its invasion success. The species may severely affect native
prey communities and modify food web structure and ecosystem functioning. Efficient and sustainable management actions are
needed to prevent further introductions in the future.O presente estudo relata a primeira ocorrência do peixe-gato-europeu Silurus glanis (Família: Siluridae) no troço português
do rio Douro, sugerindo uma potencial expansão da sua distribuição em Portugal através da dispersão natural da espécie para
oeste através deste rio internacional e/ou através de introduções realizadas pelo homem em novas albufeiras. As características particulares do peixe-gato europeu (por exemplo, predador oportunista e comportamento de caça em grupo) aumentam
quer o sucesso da sua dispersão quer o estabelecimento de populações auto-sustentáveis em novas massas de água. Esta
espécie pode afetar severamente as comunidades de presas nativas e pode modificar a estrutura da teia alimentar, assim como
mudar o funcionamento dos ecossistemas. Desta forma são necessárias ações de gestão eficazes para evitar novas introduções
desta espécie.FCTinfo:eu-repo/semantics/publishedVersio
Intracardiac Mass Due to Fibrosing Mediastinitis: The First Reported Case
We report a case of a woman, aged 53 years, presenting with a right atrial mass due to idiopathic fibrosing mediastinitis with periaortic involvement. This challenging diagnosis was confirmed by different imaging modalities and histopathologic analysis. The diagnosis of cardiac tumours is often difficult. To our knowledge, this is the first reported case of an intracavitary cardiac mass due to fibrosing mediastinitis. This rare disorder, which is characterized by invasive proliferation of fibrous tissue within the mediastinum, should be included in the differential diagnosis of intracardiac tumours
Historical food-web changes in invaded fish communities in the lower Guadiana basin
Freshwater ecosystems are increasingly being reshaped by biological invasions, leading to
biotic homogenization and biodiversity loss. However, the extent to which novel species may drive
changes in food-web structure over time remains poorly understood. Clarifying changes in historical
ecological processes is critical to inform conservation and restoration efforts in recipient ecosystems.
Here, we address food-web changes associated with fish invasions in the Lower Guadiana Basin
(LGB) over the past 40 years, by contrasting feeding relationships between museum-archived and
contemporary specimens, using stable carbon (δ13C) and nitrogen (δ15N) ratios. Specifically, trophic
niches of museum-archived fishes sampled throughout 1978–1987 and 1999–2004 corresponding to
the initial establishment and spread of non-native fishes, respectively, were compared with those of
fishes sampled in 2019, characterizing the integration of non-native species in the recipient ecosystem.
We focused on five native species (Anaecypris hispanica, Cobitis paludica, Iberochondrostoma lemmingii,
Squalius pyrenaicus and Squalius alburnoides) and four non-native species (Lepomis gibbosus, Australo heros facetus, Micropterus salmoides and Gambusia holbrooki) with potential to cover multiple trophic
positions in the food-webs. We approached historical baseline resources using prey items in gut con tents of the museum-archived fishes and characterized primary producers and macroinvertebrates in
2019. Prior to analysis, samples were normalized for high lipid content and corrected for preservation.
We found considerable asymmetries in niche partitioning among species as invasion progressed.
Over time, native species tended to be displaced to lower trophic levels, while non-native species
showed significantly higher trophic niches, driven mainly by increases in trophic (δ15N) range. Our
study highlights that stable isotopes may provide important insights on historical food-web structure
and particularly on processes underpinning ecological changes associated with anthropogenetic
pressures on freshwater ecosystems.info:eu-repo/semantics/publishedVersio
Pulmonary Metastasis in a Cardiac Angiosarcoma. Case Report and Discussion
Apresenta-se um caso clínico referente a doente de 35 anos, do sexo masculino sem antecedentes pessoais relevantes, admitido no serviço de urgência por quadro de toracalgia e tosse produtiva com alterações
electrocardiográficas sugestivas de pericardite. Inicialmente admitido pelo Serviço de Cardiologia, com melhoria do quadro clínico após terapêutica anti-
-inflamatória; contudo, no internamento houve como intercorrência pneumonia de provável etiologia bacteriana, complicada por derrame pleural. Após a alta,foi referenciado à consulta de pneumologia, onde se manteve o estudo etiológico do derrame persistente, tendo vindo a complicar-se o seu quadro com alterações das cavidades cardíacas e múltiplos nódulos pulmonares,
sugestivos de endocardite subaguda com
embolização séptica pulmonar. Internado no serviço de Pneumologia e submetido a videotoracoscopia, foi-lhe diagnosticado angiossarcoma cardíaco com metastização pulmonar. Assistiu-se a uma rápida evolução
do quadro clínico, quase fulminante, com falência cardíaca e óbito do doente sem ter iniciado radioterapia ou quimioterapia adjuvante
Fish communities in the lower Tagus inland wetlands: from anthropogenic pressures to conservation management
Inland wetlands are important biodiversity hotspots and amongst the most impacted ecosystems worldwide. Conservation management and restauration actions in wetlands are thus urgently needed to reverse trends in species loss and habitat degradation, particularly in regions harbouring already endangered endemic species. Inland wetlands may play an important role in supporting endemic endangered fishes in the Lower Tagus basin, where anthropogenic pressures have been increasing, but there is a lack of studies on fish communities, and few areas are identified as inland wetlands. Here, we aim to identify small inland wetlands in the Lower Tagus River and their potential role in supporting fish species, constituting the first study to identify and evaluate the most important fish communities. Inland wetlands were identified through the usage of remote sensing techniques and the calculation of a Normalized Difference Water Index (NDWI) with Sentinel-2 imagery for the Lower Tagus region. From a total of 486 locations identified, 31 were recognized as wetlands as having potential to host fish communities, with 11 being selected for sampling after in loco assessment. Fish sampling was conducted between 6 May and 11 June 2021. Furthermore, for each wetland, we evaluated anthropogenic stressors and land use changes between 2007 and 2018, using national land use data (i.e., Carta de Uso e Ocupação do Solo). A total of 7727 fishes from eight non-native and five native species were captured. Overall, fish communities were dominated by non-native species (97% catches), but both European eel (Anguilla anguilla) and Lisbon arched-mouth nase (Iberochondrostoma olisiponense), which are globally classified as critically endangered (CR), were found in at least two wetlands. Our results suggest that, over the last 10 years, intensive agriculture decreased (on average ≈ 3%) in the areas surrounding these wetlands, being replaced by extensive agriculture or natural uses. Despite non-native fish prevalence, some wetlands may act as refuge habitats for CR fish species. These results are important for guiding the restoration of inland wetlands and promoting conservation management actions to help reverse fish diversity loss.info:eu-repo/semantics/publishedVersio
Magnetic Properties of Weakly Doped Antiferromagnets
We study the spin excitations and the transverse susceptibility of a
two-dimensional antiferromagnet doped with a small concentration of holes in
the t-J model. The motion of holes generates a renormalization of the magnetic
properties. The Green's functions are calculated in the self-consistent Born
approximation. It is shown that the long-wavelength spin waves are
significantly softened and the shorter-wavelength spin waves become strongly
damped as the doping increases. The spin wave velocity is reduced by the
coherent motion of holes, and not increased as has been claimed elsewhere. The
transverse susceptibility is found to increase considerably with doping, also
as a result of coherent hole motion. Our results are in agreement with
experimental data for the doped copper oxide superconductors.Comment: 20 page
Avaliação da homogeneidade da mistura de dietas de bovinos confinados com diferentes ingredientes.
Objetivou-se avaliar a qualidade da mistura de duas dietas, homogeneizadas em vagão misturador (Tratomix 600, IPACOL), por meio da análise de MS
Efeito de diferentes instalações no desempenho de novilhos Nelore confinados.
O objetivo deste trabalho é verificar se as diferentes instalações podem interferir no desempenho de novilhos Nelore confinados
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