54 research outputs found

    Rail investment and port competition: a case study for the Betuweroute

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    This paper presents a study on the impact of investment in the Betuweroute and alternative transport pricing schemes on port competition between Rotterdam, Hamburg and Antwerp. The Betuweroute is a 160 kilometre dedicated freight railway line connecting the port of Rotterdam with the German Ruhr area. If the line could, in the near or more remote future, attract a large share of transit freight, it will be of considerable importance for the competitive position of the port of Rotterdam relative to Hamburg and Antwerp. We use a transport network model that includes the three ports and allows for transport by road, rail and inland waterways to and from the Ruhr area. We run model simulations for scenario’s with and without the Betuweroute and with and without marginal social cost pricing. The results show that, although the Betuweroute is a welfare reducing investment, it may indeed be of crucial importance to the port of Rotterdam

    The Impact of Effect Size Heterogeneity on Meta-Analysis: A Monte Carlo Experiment

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    In this paper we use Monte Carlo simulation to investigate the impact of effect size heterogeneity on the results of a meta-analysis. Specifically, we address the small sample behaviour of the OLS, the fixed effects regression and the mixed effects meta-estimators under three alternative scenarios of effect size heterogeneity. We distinguish heterogeneity in effect size variance, heterogeneity due to a varying true underlying effect across primary studies, and heterogeneity due to a non-systematic impact of omitted variable bias in primary studies. Our results show that the mixed effects estimator is to be preferred to the other two estimators in the first two situations. However, in the presence of random effect size variation due to a non-systematic impact of omitted variable bias, using the mixed effects estimator may be suboptimal. We also address the impact of sample size and show that meta-analysis sample size is far more effective in reducing meta-estimator variance and increasing the power of hypothesis testing than primary study sample size

    Estimating Benefits of Nature-based Solutions:Diverging Values From Choice Experiments With Time or Money Payments

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    Nature-based solutions (NBS) provide a promising means to a climate resilient future. To guide investments in NBS, stated preference studies have become a common tool to evaluate the benefits of NBS in developing countries. Due to subsistence lifestyles and generally lower incomes, SP studies in developing countries increasingly use time payments as an alternative to the traditionally implemented money payments. It remains unclear, however, how time values should be converted into money values, how the payment affects willingness to pay (WTP) estimates, and how this influence varies across settings with different levels of market integration. We compare the results of choice experiments that use either time or money payments and that are implemented in urban and rural Ghana. The choice experiments target to value different NBS aimed at erosion prevention and other ecosystem service benefits along the highly erosion prone Ghanaian coastline. Time payments are converted into monetary units using two generic wage-based conversion rates and one novel individual-specific non-wage-based conversion rate. We find higher WTP estimates for the time payments. Moreover, we find that the underlying implicit assumptions related to the currently commonly applied generic wage-based conversion rates do not hold. Finally, we find higher levels of market integration and smaller WTP disparities in the urban site, providing evidence that market integration allows for convergence of WTP estimates. These results provide guidance on the accurate estimation of NBS benefits through the implementation of stated preference studies with time payments

    Adaptation to Climate Change in the Transport Sector

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    In this study, we review the literature on climate change adaptation measures in the transport sector. Many of the measures proposed are rather conceptual and far from concrete, probably due to the fact that climate change effects on transport are either unknown or highly uncertain. Given the limited information on the potential magnitude of climate damages and the various uncertainties involved, postponement of adaptation investments may well be the most sensible strategy at the moment, especially when investments are substantial and irreversible. Furthermore, monitoring of relevant climatic changes and ongoing research into climate change effects are important elements of a pro-active adaptation strategy. Irreversible decisions, such as the ones on spatial organization, likely require a more active strategy, e.g. in the form of making spatial reservations. We further discuss the interdependency between optimal mitigation and adaptation, an issue that is often overlooked in the literature. Finally, most operators and governmental bodies are not used to dealing with risk and uncertainty, and generally base their decisions on single risk values only, likely leading to under- or overinvestment. We discuss several relevant topics in this area and highlight methods that can be used to better deal with these issues. © 2012 Copyright Taylor and Francis Group, LLC

    The Impact of Perceived Expectations and Uncertainty on Firm Investment

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    This paper analyses the (differential) impact of perceived expectations and uncertainty on investment spending in small and large firms. We analyse two types of investment, viz. aggregate investment and investment in energy-saving technologies, using Dutch firm level data. The results show that expectations and uncertainty about input- and output prices and domestic demand have substantial but different effects on investment spending in firms of different sizes. Furthermore, we find evidence, at least for small firms, that there are important differences between the effects of uncertainty about input and output variable

    A meta-analysis of the investment-uncertainty relationship

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    In this article we use meta-analysis to investigate the investment-uncertainty relationship. We focus on the direction and statistical significance of empirical estimates. Specifically, we estimate an ordered probit model and transform the estimated coefficients into marginal effects to reflect the changes in the probability of finding a significantly negative estimate, an insignificant estimate, or a significantly positive estimate. Exploratory data analysis shows that there is little empirical evidence for a positive relationship. The regression results suggest that the source of uncertainty, the level of data aggregation, the underlying model specification, and differences between short- and long-run effects are important sources of variation in study outcomes. These findings are, by and large, robust to the introduction of a trend variable to capture publication trends in the literature. The probability of finding a significantly negative relationship is higher in more recently published studies. JEL Classification: D21, D80, E22 1

    Case Reports1. A Late Presentation of Loeys-Dietz Syndrome: Beware of TGFβ Receptor Mutations in Benign Joint Hypermobility

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    Background: Thoracic aortic aneurysms (TAA) and dissections are not uncommon causes of sudden death in young adults. Loeys-Dietz syndrome (LDS) is a rare, recently described, autosomal dominant, connective tissue disease characterized by aggressive arterial aneurysms, resulting from mutations in the transforming growth factor beta (TGFβ) receptor genes TGFBR1 and TGFBR2. Mean age at death is 26.1 years, most often due to aortic dissection. We report an unusually late presentation of LDS, diagnosed following elective surgery in a female with a long history of joint hypermobility. Methods: A 51-year-old Caucasian lady complained of chest pain and headache following a dural leak from spinal anaesthesia for an elective ankle arthroscopy. CT scan and echocardiography demonstrated a dilated aortic root and significant aortic regurgitation. MRA demonstrated aortic tortuosity, an infrarenal aortic aneurysm and aneurysms in the left renal and right internal mammary arteries. She underwent aortic root repair and aortic valve replacement. She had a background of long-standing joint pains secondary to hypermobility, easy bruising, unusual fracture susceptibility and mild bronchiectasis. She had one healthy child age 32, after which she suffered a uterine prolapse. Examination revealed mild Marfanoid features. Uvula, skin and ophthalmological examination was normal. Results: Fibrillin-1 testing for Marfan syndrome (MFS) was negative. Detection of a c.1270G > C (p.Gly424Arg) TGFBR2 mutation confirmed the diagnosis of LDS. Losartan was started for vascular protection. Conclusions: LDS is a severe inherited vasculopathy that usually presents in childhood. It is characterized by aortic root dilatation and ascending aneurysms. There is a higher risk of aortic dissection compared with MFS. Clinical features overlap with MFS and Ehlers Danlos syndrome Type IV, but differentiating dysmorphogenic features include ocular hypertelorism, bifid uvula and cleft palate. Echocardiography and MRA or CT scanning from head to pelvis is recommended to establish the extent of vascular involvement. Management involves early surgical intervention, including early valve-sparing aortic root replacement, genetic counselling and close monitoring in pregnancy. Despite being caused by loss of function mutations in either TGFβ receptor, paradoxical activation of TGFβ signalling is seen, suggesting that TGFβ antagonism may confer disease modifying effects similar to those observed in MFS. TGFβ antagonism can be achieved with angiotensin antagonists, such as Losartan, which is able to delay aortic aneurysm development in preclinical models and in patients with MFS. Our case emphasizes the importance of timely recognition of vasculopathy syndromes in patients with hypermobility and the need for early surgical intervention. It also highlights their heterogeneity and the potential for late presentation. Disclosures: The authors have declared no conflicts of interes
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