ESTiG - Working Papers
Permanent URI for this collection
Browse
Recent Submissions
- Shareholders loans: a simple method of money launderingPublication . Alves, Jorge; Moreira, JoséThis study aims to discuss money laundering from a new perspective. For Mitchell et al. (1998) and Bingham (1992), among others, underlying money laundering there are complex webs of transactions with the purpose of “cleaning” illicit funds, transmitting them “through the banking system in such a way as to disguise the origin or ownership of the funds”. One reads this description and thinks of dark environments, gangsters and drug dealers. However, money can be laundered in simple ways that the literature does not discuss, and are familiar for many people. It is the case of shareholders loans that can be used as a solution for cleaning the proceedings of invoiceless sales firms make. For the Portuguese case, we gather empirical evidence and test the hypothesis that such loans are used as a laundry solution for those proceedings. We use a methodology based on two main steps. First, it classifies firms according to their tax fraud behavior by invoiceless sales; second, it relates shareholders loans to such proceedings. We found a positive relationship between these two variables. This result will be a contribution to the literature bringing into the discussion another money laundry tool.
- Near surface mounted CFRP-based technique for the strengthening of concrete structuresPublication . Barros, Joaquim; Cruz, Sena; Dias, Salvador; Ferreira, Débora; Fortes, Adriano S.To assess the effectiveness of the Near Surface Mounted (NSM) strengthening technique, an experimental program was carried out involving reinforced concrete (RC) columns and beams. In columns failing in bending the present work shows that the failure strain of the Carbon Fiber Reinforced Polymer (CFRP) laminates can be attained using the NSM technique. Beams failing in bending were also strengthened with CFRP laminates in order to double their load carrying capacity. This goal was attained and maximum strain levels of about 90% of the CFRP failure strain were recorded. Performance of externally bonded reinforcing (EBR) and NMS techniques was compared for strengthening RC beams failing in shear. NMS was much more effective, not only in terms of the increase of the load carrying capacity and deformability at beam failure, but also with respect to the time consuming nature of the corresponding strengthening procedures. To assess the bond behavior of CFRP to concrete, pulloutbending tests were carried out. The influences of bond length and concrete strength on the bond behavior were analyzed
- Criação de empresas em Portugal e Espanha: análise comparativa com base nos dados do Banco MundialPublication . Sarmento, Elsa; Nunes, AlcinaDo Inquérito ao Empreendedorismo do Banco Mundial (WBGES 2008) resultou uma extensa base de dados de cerca de uma centena de países, baseada em dados dos registos notariais. Com base nesta fonte de informação, exploram-se as trajectórias de evolução da criação de empresas entre 2000 e 2007 entre dois países geográfica e economicamente próximos, Portugal e Espanha, e destes países relativamente à União Europeia e à OCDE, bem como a outros países e fontes de informação. Análises anteriores, com base noutras fontes de informação, apontam para taxas de criação de empresas em Portugal superiores às de Espanha. Os dados do WBGES permitem validar essas conclusões. Porém, Portugal evidencia uma volatilidade superior no registo de empresas. Em 2001, o elevado acréscimo no registo de novas empresas representa um fenómeno isolado e específico para Portugal, não havendo paralelo nem nos países europeus da coesão, nem ao nível da média da União Europeia. O projecto Empresa na Hora não teve um impacto visível a nível do registo de empresas, considerando a evolução ao longo deste período. Por outro lado, Espanha detém uma densidade empresarial considerável, não só do total de empresas registadas, mas também do registo de novas empresas, apesar de Portugal apresentar taxas de crescimento médias superiores do registo de novas empresas, indiciando maiores taxas de sobrevivência empresarial que as existentes em Portugal. No entanto, de acordo com os dados dos registos de criação de empresas, apesar de Portugal e Espanha apresentarem densidades empresariais superiores à média da União Europeia e da OCDE, possuem taxas de registo de novas empresas relativamente mais baixas, o que leva a concluir por uma relativa menor dinâmica empresarial na criação de novas empresas. Finalmente, constata-se que as taxas de criação de empresas baseadas no WBGES 2008 são menos elevadas do que as obtidas quando se considera o universo de empresas economicamente activas. Este facto indica que análises comparativas de empreendedorismo não devem considerar isoladamente os dados oficiais de registo de empresas, devendo ser complementadas com outras fontes de informação, onde esteja representado o universo relevante de empresas que se encontrem efectivamente em actividade.
- Business survival in portuguese regionsPublication . Nunes, Alcina; Sarmento, ElsaThis work addresses the post-entry performance of employer enterprises for seven regions in Portugal, at the NUT II level, by investigating the structural characteristics of survival, using non-parametric and semi-parametric methods, during the period 1985 to 2007. The last decades of the 20th century were characterized by a period of creative destruction in Portugal. In particular, regions such as Norte, Algarve and Madeira show the highest growth rates in enterprise births, deaths and firm churn. After 2000, firms´ births and deaths get relatively less turbulent. In the non-parametric analysis, we identify statistically significant disparities among regions. Norte has the lowest survival rate and Centro holds the longest surviving firms and the survival gap between the former two regions gets amplified over time. Concerning the semiparametric analysis, firm’s current size dimension is a strong determinant for the probability of survival, particularly in the Norte and Açores. In industries characterized by high entry rates at the moment of a firm’s birth, post-entry survival becomes harder, especially in the south and in the Portuguese archipelagos, the regions with the lowest number of active employer enterprises. A higher entry rate combined with fast growth rates for any given industry also generates a shorter duration of firms. Manufacturing is the sector where more firms are more likely to abandon the market, particularly in Madeira and Norte. But it is turbulence, given by the sum of firms´ entry and exit rates that exhibits the most significant effect on survival. For every region, except for the Açores, where there is no statistical significance, those that have the highest record of firm turbulence, also display the lowest business survival probabilities. Turbulence decreases severely the survival probabilities of firms located in Madeira and Norte and to a lesser extent in the Algarve.
- Business creation in Portugal: comparison between the world bank data and quadros de pessoalPublication . Sarmento, Elsa; Nunes, AlcinaPortugal has some of the highest business entry rates when compared to other countries, according to Eurostat, Statistics Portugal and the OECD Entrepreneurship Indicators Programme. We look at business creation in Portugal, from 2000 to 2007, by approaching two other complementary data sources, the World Bank Group Entrepreneurship Survey, based on official Portuguese business register’s and the universe of active employer enterprises, obtained by applying to the dataset Quadros de Pessoal, the methodology and definitions of the Eurostat/OECD´s “Manual on Business Demography Statistics”. This allows us to address entrepreneurship indicators comparability issues and exploit complementarities to support entrepreneurship patterns and trends previously identified by other national and international sources. We highlight the importance of considering information other than business registries, in particular when calculating business entry rates. Datasets where economically active units can be identified provide a better proxy for the true level of business creation and activity in Portugal.
- Análise comparativa de sobrevivência empresarial: o caso da região Norte de PortugalPublication . Sarmento, Elsa; Nunes, AlcinaEste estudo aborda a capacidade de sobrevivência de empresas na região Norte de Portugal, de 1985 a 2007, fornecendo comparações regionais e nacionais, com recurso a funções de risco e sobrevivência e a métodos não paramétricos e semi-paramétricos. A análise assenta na criação de uma base de dados de empreendedorismo baseada na informação dos Quadros de Pessoal, ao qual foi aplicada a metodologia da OCDE e do Eurostat patente no “Manual Estatístico da Demografia das Empresas”. Os resultados apontam para um encerramento precoce da actividade empresarial no Norte, sendo a duração mediana da vida das empresas inferior à das restantes regiões. A elevada taxa de turbulência de entrada e saída de empresas no mercado é apontada como a variável com o efeito mais significativo nas probabilidades de sobrevivência.
- The portuguese active labour market policy during the period 1998-2003 - a comprehensive conditional difference-in-difference applicationPublication . Nunes, Alcina; Teixeira, PaulinoIn most studies in the literature only the participation in a single programme versus non-participation is evaluated. This approach, however, does not address the needs of a comprehensive evaluation of an active public intervention in the labour market. Active labour market programmes, like the Portuguese, are not restricted to a particular measure. Rather, in most cases, the public employment service offers a wide variety of programmes to the universe of potential participants. In this context, the issue is participation in one programme versus participation in an alternative programme. In particular, it is appropriate to investigate which programme presents a higher causal effect. Imbens (2000) and Lechner (2001) extended the traditional matching methodology to a context of multiple programme participation. The approach followed in this paper intends to go even further. Indeed, since the traditional matching methodology, which considers the conditional independence assumption, is not appropriate in the context of the Portuguese labour market analysis, we will adopt the assumption of the bias stability. Taking into consideration the selection on unobservables, the matching methodology, combined with the difference-in-differences methodology, will be then our selected evaluation approach. The paper presents the estimation of the average treatment effects on the treated in six distinct states (the non-participation state, plus five “active” programmes). The results, in terms of employability, are not identical across the different states in the short-run (i.e. in the first six to twelve months after participation), but they do seem to converge in the long-run (i.e. after two and a half years).
- Entrepreneurship performance indicators for employer enterprises in PortugalPublication . Sarmento, Elsa; Nunes, AlcinaThis work describes the dynamics of active and new employer enterprises in Portugal, using an entrepreneurship dataset conceived from Quadros de Pessoal, for a period of around 20 years.
- Automatic computation of conservation laws in the calculus of variations and optimal controlPublication . Gouveia, Paulo D.F.; Torres, Delfim F.M.We present analytic computational tools that permit us to identify, in an automatic way, conservation laws in optimal control. The central result we use is the famous Noether's theorem, a classical theory developed by Emmy Noether in 1918, in the context of the calculus of variations and mathematical physics, and which was extended recently to the more general context of optimal control. We show how a Computer Algebra System can be very helpful in finding the symmetries and corresponding conservation laws in optimal control theory, thus making useful in practice the theoretical results recently obtained in the literature. A Maple implementation is provided and several illustrative examples given.
- Computing ODE symmetries as abnormal variational symmetriesPublication . Gouveia, Paulo D.F.; Torres, Delfim F.M.We give a new computational method to obtain symmetries of ordinary differential equations. The proposed approach appears as an extension of a recent algorithm to compute variational symmetries of optimal control problems [P.D.F. Gouveia, D.F.M. Torres, Automatic computation of conservation laws in the calculus of variations and optimal control, Comput. Methods Appl. Math. 5 (4) (2005) 387-409], and is based on the resolution of a first order linear PDE that arises as a necessary and sufficient condition of invariance for abnormal optimal control problems. A computer algebra procedure is developed, which permits one to obtain ODE symmetries by the proposed method. Examples are given, and results compared with those obtained by previous available methods.