Browsing by Issue Date, starting with "2012-01"
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- Migration in CIS in the context of European integration and changing socio-political bordersPublication . Uzagalieva, Ainura; Chojnicki, Xavier; Filer, Randall K.; Menezes, António Gomes deLabor migration from Eastern Europe and Commonwealth of Independent States (CIS) to Western countries became an important socio-economic issue due to the large number of migrants. Since political systems and the nature of border management in these regions change, migration flows turned out to be a very complex and unpredictable issue. The purpose of this study is to analyze possible scenarios and demographic consequences of migration flows, paying particular attention to region specific factors and migration policies implemented in recent years. The paper attempts to bridge a gap in literature on this important topic, linking traditional labor market factors with uncertainty issues and policies implemented in migrant receiving countries within the CIS. Our findings suggest that economic and migration situation in the destination CIS members became a very important determinant of migration flows. In this respect, we employ a gravity model on the sample of 12 CIS members and estimate the potential size of migration flows under three migratory scenarios. Based on these scenarios, we further evaluate the demographic consequences of migration in the largest members, including Russian Federation, Ukraine and Uzbekistan which differ largely in terms demographic as well as economic and geographic conditions. The study reveals that further demographic ageing is inevitable over the next decades even if these three countries are not similarly affected. Indeed, the dependency ratio, or the ratio of retirees to the working population, should double. We conclude that reasonable migratory flows - economically motivated - will have no significant impact on these trends unless if they become substantial.
- A Matemática num contexto de Projeto Educativo: evolução, estruturação, criatividade, ensino e objectividadesPublication . Melo, Helena SousaSe partirmos dos princípios que fundamentam um Projeto Educativo, estruturados em valores, metas e estratégias, podemos também obter as linhas orientadoras de um ensino/aprendizagem da Matemática. Do mesmo modo que a escola concebe um conjunto de objetivos na sua atuação, que lhe permite cumprir a sua função educativa, o ensino/aprendizagem da Matemática possui um conjunto de estratagemas aplicáveis que possibilitam uma melhor eficácia na divulgação do seu conhecimento e no seu desenvolvimento. Com o propósito de criar um ambiente cada vez mais propício à aprendizagem, o Projeto Educativo é um guia de trabalho que assegura coerência e coesão na atividade educativa. É um promovedor de sucesso, de realização, desenvolvendo competências e consolidando valores como a interajuda, a responsabilidade e a cidadania. O ensino da Matemática possui um papel semelhante, através da sua ligação, cada vez maior, com o quotidiano.
- Island biogeography is not a single-variable discipline: the small island effect debatePublication . Triantis, Kostas A.; Sfenthourakis, SpyrosIn some island systems, an ‘anomalous’ feature of species richness on smaller islands, in comparison with larger ones, has been observed. This has been described as the small island effect (SIE). The precise meaning of the term remains unresolved, as does the explanation for the phenomenon and even whether it exists. Dengler (2010; Diversity Distrib, 16, 256–266.) addresses a number of conceptual and methodological issues concerning the nature and the detection of the SIE but fails to settle conclusively most of the issues he raises. We contend that his approach is theoretically flawed, especially in its treatment of habitat diversity. We offer a few suggestions of what is needed to advance understanding of the SIE.
- Welfare implications of pension reforms in Portugal using an overlapping generations modelPublication . Rege, Sameer; Menezes, António Gomes deNeste artigo é proposto e desenvolvido um modelo de gerações sobrepostas (OLG) de 60 períodos, com vista a análise dos efeitos de bem-estar da redução de pensões associadas a diferentes alterações de impostos. O modelo é calibrado à economia portuguesa em 2005. Os resultados indicam que a redução das pensões sem alterações em impostos resulta num aumento da utilidade, de modo sensível à elasticidade de substituição na função de produção. O corte de pensões associado a um aumento da idade da reforma tem um impacto residual na utilidade, dada a suavização do perfil do consumo ao longo da vida. O corte de pensões com alterações (aumentos/reduções) em diferentes impostos como IVA tem maiores impactos no bem estar (aumentos/perdas) do por oposição a alterações em impostos sobre o capital. São discutidas implicações de política económica à luz da temática da sustentabilidade da segurança social em Portugal.
- Diversity and community assembly patterns of epigean vs. troglobiont spiders in the Iberian PeninsulaPublication . Cardoso, PedroCave-obligate organisms usually have smaller ranges and their assemblages have higher beta diversity than their epigean counterparts. Phylogenetic and functional diversity is usually low in cave communities, leading to taxonomic and functional disharmony, with entire groups missing from the subterranean realm. The objective of this work is to compare range, beta diversity, phylogenetic and functional diversity, taxonomic and functional disharmony of epigean versus troglobiont spiders in the Iberian Peninsula. The median extent of occurrence was found to be 33 times higher for epigean than for cave species. Beta diversity was significantly higher for troglobiont assemblages. Cave assemblages present lower phylogenetic and functional diversities than expected by chance. Taxonomic disharmony was noticeable, with many speciose families, namely Gnaphosidae, Salticidae and Lycosidae, absent in caves. Functional disharmony was equally high, with ambush hunters and sensing web weavers being absent in caves. The small range and high beta diversity of troglobiont spiders in the Iberian Peninsula is typical of many cave-obligate organisms, caused by the fragmentation and isolation of cave systems and the low vagility and high habitat specialization of species. Caves were colonized mainly by pre-adapted lineages, with high proportions of eutroglophile species. Some families no longer occur in surface habitats, possibly since the last glaciations, and currently are restricted to caves in the region. Few hunting strategies and web types are efficient in caves and these dominate among the troglobiont species. As troglobiont communities are of low alpha diversity, with low functional redundancy, have narrow ranges, present high levels of population fragmentation and are taxonomically unique, they should present higher proportions of imperilled species than epigean spiders in the Iberian Peninsula. Some species are probably endangered and require urgent conservation measures.
- Biotic interactions between Eriopis connexa and Hippodamia variegata (Coleoptera: Coccinellidae), a native and an exotic species associated with alfalfa fields in ChilePublication . Grez, A. A.; Viera, B.; Soares, António O.Human-assisted introductions, including those in the context of biological control, are considered to be one of the most important factors of global environmental change. However, the mechanisms underlying environmental changes, such as a decrease in the relative abundance of native species, are poorly understood. Since the introduction of the ladybird beetle, Hippodamia variegata (Goeze) (Coleoptera: Coccinellidae), in Chile in the 1970s for biological control of aphids, a reduction in the relative abundance of the native ladybird beetle Eriopis connexa (Germar) has been noticed. To explore the role of cannibalism, intraguild predation (IGP) or competition as possible mechanisms that might increase dominance of H. variegata over E. connexa, several laboratory experiments were carried out. The native and the exotic species were very similar in their voracity and biotic interactions. Although H. variegata was able to maintain constant reproductive performance, E. connexa reproduction decreased at lower densities of aphids, Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae). The impacts of cannibalism, IGP, and competition exerted by these species were very symmetrical in both larvae and adults. We conclude that these biotic factors may not fully explain the increase in relative abundance of H. variegata. The higher sensitivity of E. connexa to prey patch size, along with other factors such as chemical-mediated negative interspecific interactions may be operating in alfalfa fields, changing the composition of associated coccinellid assemblages.
- Technological innovation in New European Union MarketsPublication . Uzagalieva, Ainura; Kočenda, Evžen; Menezes, António Gomes deWe analyze the role of innovation in the technological development of four new EU members: the Czech Republic, Hungary, Poland and Slovakia. For that purpose, we use a novel approach by modeling the empirical relationship between intra-industrial bilateral trade flows, which proxy the level of technological progress, and innovation expenditures within the context of a gravity model with a set of appropriate instrumental variables to account for the potential endogeneity of innovation to trade. We show that innovation efforts in high-tech industries exhibit a strong effect on the technological progress of the region and they are closely linked to foreign direct investment and multinationals. As foreign-owned subsidiaries become a part of the innovation systems and industrial structure of the host country they promote overall technological growth in the region.
- Preliminary study on diversity of the Laurentia Complex Rhodophita, Ceramiales in the Macaronesian region assessed by DNA barcoding and phylogenetic inferencesPublication . Machín-Sánchez, María; Le Gall, L.; Neto, Ana I.; Díaz-Larrea, Jhoana; Cassano, Valéria; Sentíes, Abel; Fujii, Mutue T.; Gil-Rodríguez, María C.
- Volcanic caves : priorities for conserving the Azorean endemic troglobiont speciesPublication . Borges, Paulo A. V.; Cardoso, Pedro; Amorim, Isabel R.; Pereira, Fernando E. A. P.; Constância, João P.; Nunes, João Carlos; Barcelos, Paulo; Costa, Paulino; Gabriel, Rosalina; Dapkevicius, Maria de Lurdes N. E.Azorean lava-tubes and volcanic pits adequately sampled for arthropod fauna were evaluated for species diversity and rarity. An iterative partial multiple regression analysis was performed to produce a multi-criteria index (Importance Value for Cave Conservation, IV-CC) incorporating arthropod species diversity indices but also including indices qualifying cave geological and management features (e.g., the diversity of geological structures, threats, accessibility). Additionally, we calculated complementarity solutions (irreplaceability and Fraction-of-Spare measures) for each cave with different targets per species, i.e., the minimum number of caves needed for each species to be represented either once or twice. Our results clearly show that to preserve all troglobiont arthropods endemic to the Azores, it is crucial to protect several caves per island. As many as 10 and 15 caves are needed to include one or two occurrences, respectively, per species.
- The demand of car rentals : a microeconometric approach with count models and survey dataPublication . Menezes, António Gomes de; Uzagalieva, AinuraThe purpose of this study is to analyze the demand side of the tourist market in a small island economy, the Autonomous Region of the Azores, a Portuguese region experienced a rapid growth in the tourism sector in the last decade. Azorean islands are, normally, a “fly-anddrive” destination given the high frequency of car rentals by the tourists. It is well known that the excessive use of cars can lead to negative externalities such as pollution and the degradation of roads. Considering the growing number of tourist in the Azores and ecological fragility that is typical for small islands, it is crucially important to investigate the extent of these negative externalities. This phenomenon is very important in terms of policy-making on the management of tourism in small island economies as well as in the global environmental context from the perspectives of effective "eco-taxes", used as instruments for internalizing negative externalities and enhancing environmental protection. To this end, the demand function of car rentals is analyzed with the use of the family of count models and the unique micro-level survey data, conducted on a large number of tourists visited the region. Based on the price elasticity of demand for care rentals, we then suggest desired tax rates for internalizing the congestion costs.
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