1,275 research outputs found
Brief on Discounting in the Context of Climate Change Economics
human development, climate change
Constraints on Dematerialisation and Allocation of Natural Capital along a Sustainable Growth Path
This paper extends the neoclassical growth model with natural capital by introducing two new concepts: allocation of natural capital and materialization. We consider that anthropogenic environmental impact is correlated with the throughput of the economy (materialisation). Materialisation is the material throughput per unit of economic activity. We capture the effect of the reduction of this throughput dematerialisation in the elasticities of materialisation and aggregate environmental impact. In our framework the fraction of natural capital devoted to production does not provide direct environmental services nor does it contribute to ecosystem functioning namely affecting the carrying capacity of natural capital.We analyse an optimal sustainable growth path, in the context of exogenous technological change. Our main conclusion is that the ratio of dematerialisation elasticities must equal the inverse of the share of natural capital in order to assure unbounded economic growth with constant natural capital
Public Employment systems in XXI century: what means? An systematization
O presente artigo intenta sistematizar as formas ou regimes do emprego público em países da União Europeia e da OCDE. A metodologia compreende a análise dos tradicionais sistemas de carreira (career-based system) e sistema de emprego (position-based system) no emprego público. Desenvolvem-se, ainda, breves reflexões nas mudanças operadas naqueles dois regimes que migraram para um terceiro modelo, vulgarmente designado por modelo híbrido de emprego público, mais flexível e mais correlativo às circunstâncias do século XXI.This article intends to systematize the forms or systems of public employment in EU countries and the OECD. The methodology includes the analysis of traditional career systems (career-based system) and the employment system (position-based system) on public employment. We Develop, yet, concise reflections on the changes occurred in those two schemes that have migrated to a third model, commonly called a hybrid model of public employment. This model reveals more flexible and correlative to the circumstances of the twenty-first century
La ausencia de una política fiscal keynesiana:¿ consolidación fiscal expansiva o contractiva? Estudio de caso: Portugal
No presente artigo faz-se uma revisão da literatura teórica e empírica dos efeitos
não-keynesianos da política orçamental e o estudo do caso português no período1980-2005.
Discutem-se as perspectivas keynesiana, ricardiana e neoclássica
dos efeitos dos défices na actividade económica, descrevem-se os efeitos não-keynesianos
da política orçamental numa perspectiva teórica e empírica; igualmente
identificam-se os episódios de consolidação orçamental na economia portuguesa
e avalia-se o sucesso destas consolidações; e, por último, apresentam-se as conclusões.En el presente artículo se entrega una revisión de la literatura teórica y empírica
de los efectos de ausencia de la política fiscal keynesiana en el caso de Portugal
para el periodo 1980-2005. Se analizan las perspectivas Keynesianas, ricardianas
y neoclasicas de los efectos de los déficit en la actividad económica; del mismo
modo, se describe los efectos no keynesianos de la política fiscal una perspectiva
teórica y empírica, y se identifican episodios de consolidación fiscal en la economía
portuguesa, para finalizar se evalúa el éxito de estas consolidaciones
El impacto de la introducción de impuestos proporcional en los ingresos fiscales y el desempeño económico: las experiencias de los nuevos estados miembros de la UE-27
Nos últimos anos tem-se debatido o regresso a sistemas de impostos
proporcionais em muitas economias europeias. Apesar do sistema de
impostos proporcionais puro nunca ter sido introduzido em nenhuma
economia, alguns aspectos deste sistema foram postos em prática em cerca
de trinta países. Neste artigo analisam-se algumas das experiências dos
Novos Estados Membros da União Europeia que implementaram impostos
proporcionais, averiguando o seu impacto sobre as receitas fiscais, saldo
orçamental, crescimento económico e desemprego. A análise estatística
permite concluir que as receitas fiscais aumentaram na maior parte
daquelas economias e que observaram taxas de crescimento económico
muito mais elevadas do que os restantes Novos Estados Membros com
sistemas de impostos progressivos.En los últimos años se ha debatido sobre el retorno a los sistemas de
impuesto proporcional en muchas economías europeas. A pesar de que
el sistema fiscal proporcional puro nunca fue introducido en ninguna
economía, aspectos de este sistema se llevaron a cabo en unos treinta países,
algunos de los que forman la Unión Europea. En este artículo se analizan
algunas de las experiencias de los nuevos estados miembros de la Unión
Europea que han implementado impuestos proporcionales mediante el
examen de su impacto en los ingresos fiscales, equilibrio presupuestario,
el crecimiento económico y el desempleo. El análisis estadístico muestra
que los ingresos tributarios aumentaron en la mayoría de las economías y
las tasas observadas de crecimiento son mucho mayores que en los otros
nuevos estados miembros que utilizan sistemas de tributación progresiva
¿La corrupción inhibe la inversión extranjera directa?
Globalization creates new opportunities for firms to invest abroad and many
economies are making active efforts to attract Foreign Direct Investment (FDI)
in order to promote economic growth. Decisions to invest abroad depend on a
complex set of factors, but the least corrupt countries may attract more foreign
direct investment because they provide a more favorable climate for investors.
In this paper we investigate the impact of corruption on FDI inflows in 73
countries, over the period 1998-2008. Our results suggest that countries where
corruption is lower, the FDI inflows are greater, and so controlling corruption
may be an important strategy for increase FDI inflows.La globalización ha creado nuevas oportunidades para invertir en el extranjero
y muchas economías están haciendo esfuerzos para atraer inversión extranjera
directa (IED) con el fin de promover el crecimiento económico. La decisión
de invertir en el extranjero depende de un complejo conjunto de factores. No
obstante, los países menos corruptos pueden atraer más inversión extranjera
directa, ya que proporcionan un clima más favorable para los inversionistas. En
este trabajo se investiga el impacto de la corrupción sobre los flujos de IED
en 73 países, en el período 1998-2008. Los resultados sugieren que los países
donde la corrupción es menor, las entradas de IED son mayores, por lo que el
control de la corrupción puede ser una estrategia importante para aumentar
los flujos de IED
Mapear o estudar no ensino superior : abordagens dos alunos ao estudo numa E.S.E.
Integrado na linha de investigação SAL (Students Approaches to Learning),
este trabalho centra-se no estudo da perspectiva dos alunos sobre a sua experiência de
aprendizagem. Assim, o objectivo da presente investigação centrou-se na avaliação das
abordagens à aprendizagem dos alunos do ensino superior, mais precisamente numa
Escola Superior de Educação do ensino particular, situada no Porto. Os resultados obtidos
sugerem que os alunos optam preferencialmente por uma abordagem profunda à
aprendizagem. Esperamos que este estudo possa contribuir para uma melhor compreensão
da aprendizagem dos alunos no ensino superior, sobretudo no momento actual do sistema
de ensino universitário em reformulação de currículos e metodologias para dar cumprimento
às sugestões de “Bolonha”, promovendo alunos cada vez mais autónomos na sua
aprendizagem e, consequentemente, responsáveis pela construção do seu próprio saber.Integrating the research on Students Approaches to Learning (SAL) this article
focuses on students’ perceptions of their own learning experience.
Evaluating students’ approaches to learning was the main goal of the empirical study presented
here. The sample integrated students from a private School of Education in
Oporto. Data suggest that students opt for the use of a deep approach to learning. We
hope this study highlights a better understanding of students’ approaches to learning.
According to present demands of Bologna rules, deep changes in university curricula and
teaching methodologies are urgent so that students’ autonomy and responsibility for their
own building of knowledge can be promoted
The Terceira Rift, Azores: a melt inclusion study of submarine lavas
The Azores plateau, a bathymetric high, is seated on an anomalous mantle domain located in the Azores Triple Junction where the American, EUR and AFR lithospheric plates meet. The cause for these anomalies is controversial but many authors consider the presence of an anomalously hot/wet enriched mantle probably supplied by a plume [3]. The origin, size and present location of the plume is under debate but an area near Terceira is the favoured plume centre [2]. The Terceira Rift (TR) defines the EUR/AFR plate boundary of the Azores triple junction. The TR is a 550 km long, generally ESE trending line of volcanic massifs along the axis (e.g. São Miguel, D. João de Castro, Terceira and Graciosa) alternating with deep basins (e.g. Hirondelle basin) interpreted as volcanically unfilled rift valley segments [3]. Vesicular, porphyritic basalts were sampled along the Terceira Rift during Portuguese scientific cruises (EMEPC 2007-2009). Initial studies focused on the adjacent areas Don João de Castro - DJC (submarine volcano) and Hirondelle - Hir (basin). Major and trace element data of phenocrysts (olivine, clinopyroxene, plagioclase), groundmass and exposed melt inclusions found in these vesicular lavas depict only slight differences between the two sites. DJC samples depict higher Fo and Mg# in olivine and clinopyroxene, respectively. Chondrite-normalized REE data indicate that groundmass material is LREE-enriched in both Hir and DJC lavas. Exposed melt inclusions (MI) show similar REE patterns compared to their hosts. Clinopyroxene in both sites display L-MREE enriched, HREE depleted sinusoidal patterns. MI were found in olivine, clinopyroxene and plagioclase phenocrysts. MI are glassy to completely opaque and devitrified, with one or more bubbles, and sulfide globules (SG). SG are spherical, depict two-phase lamellar intergrowths of Fe-Ni and Cu-Fe phases, and are ubiquitous in DJC and Hir lava samples. Some lavas display SG within clinopyroxene-hosted MI and dispersed in the groundmass. Preliminary data suggest that lavas found in these areas of the Terceira Rift were sulfur-saturated in different stages of their evolution; during early fractionation and prior to eruption. The geochemistry of melt inclusion will contribute to the understanding of mantle source, melting and mixing processes in the Terceira Rift, Azores
Numerical simulation of two-degree-of-freedom vortex induced vibration in a circular cylinder with OpenFOAM
Computational fluid dynamics tools are capable to simulate the influence of a fluid flow
passing around an object. The ability to predict the impact of such flows on a specific
product performance is time consuming and costly without some form of simulation
tool. In fact, across a wide range of engineering areas, virtual development allows the
reduction of the number of prototypes and less testing until a product is ready to the
market. Therefore, it is important to provide computational fluid dynamics users with
easy-to-use, robust, time-efficient and validated processes. Bearing this in mind, the
current thesis studies the phenomenon of vortex induced vibrations simulating a flow
around an oscillatory cylinder.
A flow passing around a rhombic body originates dynamic forces which, consequently,
induce a set of body movements that are well characterized in the literature. To perform
the numerical investigation of this phenomenon was used the OpenFOAM, an opensource software which is numerically able to perform a detailed and accurate analysis of this complex phenomena. Given the few scientific studies about the vortex induced vibration phenomenon with two degrees of freedom, this thesis aims to validate the Open-FOAM software for this case study, providing the scientific community the validation of a new numerical tool for studies of this kind. With this goal, it was firstly performed a mesh independence study for a flow around a fixed cylinder where it was studied the influence of the mesh on the fundamental quantities, that is, the Strouhal number, St, the mean drag coefficient, CD,mean, and the root mean square of the drag, CD,rms, and lift, CL,rms, coefficients.
Then, it was carried out the study of the flow around a cylinder with one degree of
freedom. It was studied the response of the cylinder for two types of systems, mass-spring system and mass-spring-damper system for a mesh with a 2500D domain length. The obtained results where then compared with the data described in the literature for a 50D length mesh, allowing to infer which is the impact of the mesh size into the obtained results.
Finally, it was studied the phenomena generated by a flow around a cylinder with two
degrees of freedom. In order to validate this analysis, the obtained results for a 8D mesh were compared with the data described in the literature for a similar numeric study. The main difference obtained between both studies was the symmetry of the geometry of the cylinder’s oscillatory movement which was obtained by the current study whereas the comparative study showed an asymmetric movement of the cylinder. Given this data, it was hypothesised and proven that this fact was associated with the non-symmetry of the mesh used by the literature paper.
Subsequently, it was studied the influence of the mesh refinement level in the response
given by the cylinder with two degrees of freedom. It was also analysed how the size of
the mesh domain influences the response given by the cylinder with two degrees of
freedom. Particularly, it was compared the geometry of the oscillatory motion and the
temporal evolution of the respective lift coefficient between meshes with 8D, 20D, 500D
and 2500D size
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