Scoring auctions: are they the key to marketbased allocation of airport slots?

Air transport has increased almost fifteen-fold worldwide in the last half-century (1970- 2019) and is expected to return to this trend in the next few years, after falling from 4.558 billion passengers in 2019 to 1.809 billion passengers in 2020 due to the Covid-19 pandemic. Airport capacity has not kept pace with such growth and, therefore, more than two hundred major airports worldwide face capacity constraints and are “coordinated”. Efficient allocation of scarce airport capacity is critical for air traffic growth, as well as for the overall air transport dynamic efficiency. However, the allocation of airport slots in Europe and elsewhere is still ruled by administrative processes, based on the IATA Worldwide Slot Guidelines, which follow historical precedence (called “Grandfather Rights”) and time adjustments of historical slots. Several objections have been raised to the adoption of market mechanisms in slot allocation, as an alternative to administrative processes, and they are still rarely used. Despite often being suggested in the literature, the use of auctions for slot allocation has only been implemented in some local routes in China, and apparently this underemployment of auction mechanisms has been due to the reluctance of coordination authorities to face the risks that have been pointed out regarding airlines’ long-term route planning, the usage costs related to excess slots, origin-destination pairing, and competition distortions. However, scoring auctions have never been considered and our research shows that their properties combined with an appropriate auction design could overcome most of those objections and mitigate the associated risks. Furthermore, the current drop in air traffic provides an opportune window for the introduction of auctions as a mechanism for the allocation of airport slots with minimal risks of disruption to airline business models

Skeleton geometry, physical activity and proximal femur bone mass distribution in 8-12 year old children

Doutoramento em Motricidade Humana, especialidade em Actividade Física e SaúdeIn the context of bone health promotion, the aim of this Ph.D dissertation was to analyze potential explanatory factors of the effects of physical activity and of bone geometry on bone mass distribution at the proximal femur in 8-12 year old children. Four studies were undertaken to compare the bone mineral density (BMD) between: (a) the sub-regions of the proximal femur – the neck and its superolateral and inferomedial aspects, the trochanter and the intertrochanter; (b) sexes, concerning the associations/effects of non-targeted physical activity and bone geometry. Sex and regional specific effects of non-targeted physical activity on bone mass distribution at the proximal femur in children were observed. The geometry of the pelvis and the proximal femur, namely the pelvis width and the abductor lever arm, emerged as predictors of bone mass distribution at the proximal femur, therefore as explanatory factors of both the regional and the sex specific patterns. These geometric features might mediate the physical activity effects on bone mineralization at the proximal femur, as long as, when they are considered, the power of physical activity to explain the distribution of bone mass at this skeletal site seems limited.Resumo : No contexto da promoção da saúde óssea, o objetivo desta dissertação de doutoramento foi analisar potenciais fatores explicativos dos efeitos da atividade física habitual e da geometria óssea na distribuição da massa óssea do fémur proximal, em crianças de 8-12 anos de idade. Para o efeito foram realizados quatro estudos comparando a densidade mineral óssea (DMO) entre: (a) as diversas sub-regiões do fémur proximal - o colo do fémur e os seus aspetos supero-lateral e infero-medial, o grande trocanter e a sub-região intertrocantérica; (b) os sexos, relativamente às associações/efeitos da atividade física habitual e da geometria óssea. Foram observadas associações/efeitos da atividade física habitual na massa óssea do fémur proximal diferenciados quanto ao sexo e sub-região. A geometria da pélvis e do femur proximal, nomeadamente a largura da pélvis e o braço de momento de força dos abdutores, surgiram como preditores da distribuição de massa óssea no fémur proximal e consequentemente como fatores explicativos de diferenciação da distribuição de massa óssea de acordo com o sexo e sub-região. Estas caraterísticas geométricas poderão mediar os efeitos da atividade física na mineralização do femur proximal uma vez que quando consideradas parecem limitar a capacidade explicativa da atividade física na distribuição de massa óssea no fémur proximal.FCT - Fundação para a Ciência e a Tecnologi

Market-based allocation of airport slots : the PAUSE auction mechanism and extensions

During the past several months, passenger air transport has been recovering from its significant retraction during the two years Covid pandemics. If the recent significant drop in air traffic due do the Covid pandemics acted as an external mitigating factor to airport traffic congestion in several major airports around the world, with the post-pandemics air traffic recovery it is likely that airport capacity will, once again, fall short of demand and not keep pace with the growth in air traffic. That is why close to two hundred major airports worldwide, most of them in Europe, face capacity constraints and are “coordinated”. Eurocontrol predicts Europe's capacity shortage in 2050 at 500,000 flights/year in the baseline scenario, which could rise to 2.7 million in an optimistic scenario. The allocation of airport slots in Europe and elsewhere is still ruled by administrative processes, based on the IATA (International Air Transport Association) Worldwide Airport Slot Guidelines (WASG), which follow historical precedence and time adjustments of historical slots. Market mechanisms in slot allocation, as an alternative to administrative processes, are still rarely used. Several authors have highlighted the inefficiency of the current airport slot administrative allocation system, based on the IATA’s Guidelines. Several authors have suggested improvements in this administrative system, such as congestion pricing mechanisms and other market mechanisms involving auction procedures. Among the various auction mechanisms, scoring auctions and the PAUSE methodology have been suggested in the literature. In this paper, and following our previous work, we explore and extend the application of the PAUSE auction mechanism with bidding based on a score function for the auctioneer, that includes another variable in addition to the total revenue, where this variable can represent e.g., quality of the service provided. We study the application of this auction mechanism, in a gradual fashion, p.e. to the year round three level 3 international airports operating in Portugal. The different airlines using these airports would still follow the current IATA slot allocation guidelines in their use of other airports, including the slot exchange protocols. We show that some of PAUSE auction mechanism’s desirable properties, such as computability, transparency, absence of envy, and the mitigation of the “price-jump problem”, “threshold problem”, “exposure problem”, and “winner’s curse problem”, still hold.info:eu-repo/semantics/publishedVersio

Monopólios públicos vs monopólios privados : eficiência produtiva em public utilities

As empresas privadas são apresentadas pela teoria económica como sendo superiores as públicas, relativamente à sua eficiência produtiva, mas estas últimas com a vantagem de, em mercados não concorrenciais, gerarem maior eficiência de afectação. Ao percorrermos as razões apontadas, com base numa fórmulação da Teoria da Agenda entre Accionistas e Gestores, para a maior eficiência produtiva das empresas privadas, parece-nos legítimo considerar que grande parte delas tern uma eficácia questionável no quadro de urn monopólio natural e/ou que não são intrínsecas à natureza da empresa privada, pelo que são factores de estímulo a eficiência produtiva replicáveis para as empresas públicas. Neste caso o diferencial de eficiência produtiva entre urn monopólio privado regulado e um monopólio público será considera­velmente menor do que é habitualmente assumido pela literatura

The use of multi-criteria analysis in the recovery of abandoned mines: a study of intervention in Portugal

Tendo em consideração a existência de uma limitação orçamentária que inviabilizava a recuperação de todas as áreas mineiras abandonadas, foi necessário desenvolver um modelo que permitisse escolher quais as minas que seriam objeto de intervenção, tendo em consideração os diferentes fatores de avaliação de seus efeitos externos (no ambiente, na saúde pública, na paisagem e no seu aproveitamento para a arqueologia industrial). A partir de uma análise multicritério (utilizando o Analytical Hierarchy Process - AHP), onde cada fator preponderante, resultado e mina foram comparados, gerou-se um modelo inovador de avaliação onde se garantiu a maximização do valor global da intervenção, em comparação a outros dois métodos (intervenção ordenada pela maior gravidade global e pela relação custo-benefício). Os resultados apontam para uma escolha econ×mica e socialmente viável e eficiente, permitindo instigar novos estudos análogos.Considering that the budget for the recovery of abandoned mining zones is limited, it was necessary to develop a model that would make it possible to choose which mines should be targeted for intervention, taking into account the various factors by which their external effects may be assessed (the environment, public health, the landscape and their usefulness to industrial archaeology). A multi-criteria analysis using the analytic hierarchy process, in which each major factor, result, and mine are compared, was employed to generate an innovative assessment model that guaranteed that the overall value of the intervention was maximised, compared to two other methods (intervention ranked by the greatest overall severity and ranked by the cost-benefit ratio). The results indicate an economically and socially viable and efficient choice, making it possible to undertake new similar studies

The use of multi-criteria analysis in the recovery of abandoned mines: a study of intervention in Portugal

Considering that the budget for the recovery of abandoned mining zones is limited, it was necessary to develop a model that would make it possible to choose which mines should be targeted for intervention, taking into account the various factors by which their external effects may be assessed (the environment, public health, the landscape and their usefulness to industrial archaeology). A multi-criteria analysis using the analytic hierarchy process, in which each major factor, result, and mine are compared, was employed to generate an innovative assessment model that guaranteed that the overall value of the intervention was maximised, compared to two other methods (intervention ranked by the greatest overall severity and ranked by the cost–benefit ratio). The results indicate an economically and socially viable and efficient choice, making it possible to undertake new similar studies. © 2018 Departamento de Administrac¸ao, Faculdade de Economia, Administrac ˜ ¸ao e Contabilidade da Universidade de S ˜ ao Paulo – FEA/USP. ˜ Published by Elsevier Editora Ltda. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

A regulação do Transporte Ferroviário e a Directiva 2001/14/CE Algumas implicações para o modelo de regulação em Portugal

A alteração das estruturas dos mercados dos serviços de transporte ferroviário alia à necessidade de regular o tradicional problema das extemalidades negativas a regulação das relações entre o gestor das infraestruturas e os prestadores de serviços. No artigo procura analisar-se os passos dados na regulação dos caminhos de ferro portugueses e relê-los à luz da nova directiva comunitária, apresentando-se sérias reservas ao alcance das medidas nela propostas

Do bone mineral content and density determine fracture in children? A possible threshold for physical activity

BackgroundRelations between bone parameters, physical exertion, and childhood fractures are complex. We aimed to estimate the associations between fracture history and bone mineral content (BMC) and areal bone mineral density (aBMD) at 7 years of age, by levels of physical activity, as a proxy for trauma frequency.MethodsWe used data collected from 2,261 children of the Generation XXI birth cohort, assembled in 2005/6 in Porto, Portugal. At the age of 7 years (2012/4), fracture history, time spent per week in active play, and sports practice were reported by parents. Subtotal and lumbar spine (LS) BMC and aBMD were measured using whole-body dual-energy X-ray absorptiometry.ResultsBoys and girls in the highest categories of time spent in sports practice or active play generally had higher BMC and aBMD. Among girls, BMC and aBMD were protective of fracture only in the highest quarter of active play (>660 min/week)-odds ratios (OR; 95% confidence interval (95% CI)) for subtotal BMC=0.27 (0.11-0.67), subtotal aBMD=0.18 (0.06-0.49), and LS aBMD=0.41 (0.22-0.75). For boys in the highest quarter of sports practice (>240 min/week), subtotal and LS BMC were protective of fracture-OR=0.39 (0.16-0.98) and 0.51 (0.27-0.96), respectively.ConclusionIn prepubertal children, BMC and aBMD predicted fracture history only in the highest levels of physical activity.info:eu-repo/semantics/publishedVersio