Environmental Policy and the Macroeconomy in the Presence of Ecological Thresholds

We study the environmental and economic effects of public abatement in the presence of multiple stable steady-state ecological equilibria. Under shallow-lake dynamics (SLD), the isocline for the stock of pollution features two stable branches, a good and a bad one. Assuming that the ecology is initially located on the upper (bad) branch of the isocline, the ecological equilibrium is hysteretic and a suitably designed temporary abatement policy can be used to steer the environment from the bad to the good equilibrium. In all models considered in this paper, a “cold turkey” abatement policy is optimal, i.e. the largest feasible shock should be administered for the shortest possible amount of time. Depending on the particular model used to characterize the economic system, there is a capital feedback effect that either helps or hinders the attainment of a successful abatement policy.Shallow-lake dynamics, Bifurcation, Environmental policy, Overlapping generations

Psychometric Properties of Questionnaires on Functional Health Status in Oropharyngeal Dysphagia: A Systematic Literature Review

Introduction. Questionnaires on Functional Health Status (FHS) are part of the assessment of oropharyngeal dysphagia. Objective. To conduct a systematic review of the literature on the psychometric properties of English-language FHS questionnaires in adults with oropharyngeal dysphagia. Methods. A systematic search was performed using the electronic databases Pubmed and Embase. The psychometric properties of the questionnaires were determined based on the COSMIN taxonomy of measurement properties and definitions for health-related patient-reported outcomes and the COSMIN checklist using preset psychometric criteria. Results. Three questionnaires were included: the Eating Assessment Tool (EAT-10), the Swallowing Outcome after Laryngectomy (SOAL), and the Self-report Symptom Inventory. The Sydney Swallow Questionnaire (SSQ) proved to be identical to the Modified Self-report Symptom Inventory. All FHS questionnaires obtained poor overall methodological quality scores for most measurement properties. Conclusions. The retrieved FHS questionnaires need psychometric reevaluation; if the overall methodological quality shows satisfactory improvement on most measurement properties, the use of the questionnaires in daily clinic and research can be justified. However, in case of insufficient validity and/or reliability scores, new FHS questionnaires need to be developed using and reporting on preestablished psychometric criteria as recommended in literature

Failures in adaptive locomotion in healthy young adults

Young adults fall most frequently when walking, and trips account for 25% of these falls (Heijnen & Rietdyk, 2016). Common approaches to understanding tripping include the examination of behavior when a stationary obstacle is crossed successfully, or to deliberately trip the participant with a covert obstacle. However, these approaches do not establish the underlying cause of failure; examining inadvertent failures does, as this occurs most often in the field (Heijnen & Rietdyk, 2016). In order to identify the behavior that results in obstacle contact, this dissertation examined gait characteristics during inadvertent failures and manipulated the sensory information available to guide the limb trajectory. Manipulating the availability of sensory information is important to determine the information used to successfully guide the limbs, particularly the trail limb. Three experiments were conducted to systematically examine the role of visual and somatosensory information in young adults. I hypothesized that young adults would contact the obstacle due to incorrect foot placement when visual and somatosensory information were not manipulated. I hypothesized that healthy young adults would be able to use an obstacle memory to successfully cross the obstacle when both feedforward visual information and somatosensory information regarding obstacle contact were not available. Finally, I hypothesized that healthy young adults would progressively decrease foot clearance, resulting in values that would result in contact if the obstacle were still in place, when somatosensory information regarding obstacle contact was not available. My work has increased the understanding of several factors related to adaptive locomotion: failures, obstacle memory, and limb independence. First, obstacle contacts occurred most frequently with the trail limb and were mainly due to inadequate foot elevation. Obstacle contacts were caused by a progressive decrease in foot elevation with repeated trials in combination with high variability. Second, humans used an obstacle memory to guide the trail limb over the obstacle, and visual information gathered while walking up to the obstacle was important to establish this obstacle memory. Knowledge of results (i.e. failures) was used to update the obstacle memory. Finally, different behavior between the lead and the trail limb supported the argument that the limbs are controlled independently. Overall, a wide variety in behavior between participants was observed, highlighting the difficulties in developing a universal fall-prevention program. My work has expanded the understanding of adaptive locomotion by establishing the cause of inadvertent failures and the sensory information used to establish an obstacle memory in order to ensure safe travel through a cluttered environment

The Diffusion of Local Differentiated Waste Disposal Taxes in the Netherlands

The diffusion of a novel taxing scheme (among Dutch municipalities over the period 1998-2005) is studied in which the waste disposal tax is increasing in the amount of waste a household produces. Inspection of the rise and spread of this tax shows that it is contagious: the probability of introduction is increasing in the number of neighboring municipalities that have already introduced this taxing scheme. A possible rationale is that the tax encourages the dumping of waste in neighboring municipalities. These municipalities may then introduce a similar tax to prevent dumping (spillover effect). Using panel data and a recently developed spatial probit approach (Elhorst et al. in J Appl Econom 32:422-439, 2017), it is possible to distinguish this spillover effect from time-specific effects. The results indicate the presence of strong spillovers

Reversible Environmental Catastrophes with Disconnected Generations

We study environmental policy in a stylized economy-ecology model featuring multiple deterministic stable steady-state ecological equilibria. The economy-ecology does not settle in either of the deterministic steady states as the environmental system is hit by random shocks. Individuals live for two periods and derive utility from the (stochastic) quality of the environment. They feature warm-glow preferences and engage in private abatement in order to weakly influence the stochastic process governing environmental quality. The government may also conduct abatement activities or introduce environmental taxes. We solve for the market equilibrium abstracting from public abatement and taxes and show that the ecological process may get stuck for extended periods of time fluctuating around the heavily polluted (low quality) deterministic steady state. These epochs are called environmental catastrophes. They are not irreversible, however, as the system typically switches back to the basin of attraction associated with the good (high quality) deterministic steady state. The paper also compares the stationary distributions for environmental quality and individuals' welfare arising under the unmanaged economy and in the first-best social optimum

On infrastructure network design with agent-based modelling

We have developed an agent-based model to optimize green-field network design in an industrial area. We aim to capture some of the deep uncertainties surrounding infrastructure design by modelling it developing specific ant colony optimizations. Hence, we propose a variety of extensions to our existing work, first ideas on how to realize them and three cases to explicate our ideas. One case is the design of a CO2 pipeline network in Rotterdam industrial area. First simulation results have shown the relevance of the approach. Keywords-Infrastructure design, network planning, ant colony optimization, deep uncertainty, socio-technical systems