26 research outputs found

    Context dependencies in housing choice behavior

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    Existing experimentally based decompositional models of housing preferences and choice behavior do not account for possible substitution or context dependencies among choice alternatives. These authors seek to extend existing models by demonstrating how discrete choice experiments may be used to develop housing choice models that allow one to test for possible context dependencies. The design strategy and model specification are discussed. The modelling approach is illustrated in the context of simulated housing choices of divorcees. The results indicate that context dependencies play a significant role in the understanding of these people's housing preferences and choices.

    Modeling constrained choice behaviour in regulated housing markets by means of discrete choice experiments and universal logit models: an application to the residential choice behaviour of divorcees

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    In present choice models, it is assumed that the composition of individuals' choice sets does not affect their utilities. Preferences and choice behaviour are assumed to be independent of context. The constraints that individuals face are not modeled explicitly in the residential choice literature. In this paper we aim to propose and demonstrate how discrete choice experiments and universal logit models may be used to estimate choice models that permit one to measure and test the effects of constraints on housing choice behaviour and residential preferences. In particular, we wish to test whether preferences of divorcees are invariant with differential access to housing-market segments. The empirical findings obtained in the present study of residential choices of divorcees generally support the idea that access to particular segments affects the preference for other segments differentially. Estimated attribute effects were in anticipated directions, although not all were significant. The choice model, including the effects representing access to particular housing-market segments, outperformed the multinomial logit model at conventional probability levels, and odds ratios were shown to change dramatically as a function of the constraints on residential choice behaviour.

    Longitudinal follow-up in female Childhood Cancer Survivors : no signs of accelerated ovarian function loss

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    STUDY QUESTION: Is the long-term decline of ovarian function, as reflected by a decrease in serum anti-Müllerian hormone (AMH) concentration, accelerated over time in female childhood cancer survivors (CCS) as compared to healthy women of the same age? SUMMARY ANSWER: The median decline of AMH levels in long-term female CCS is not accelerated and similar to that observed in healthy controls. WHAT IS KNOWN ALREADY: Gonadal function is compromised in female CCS treated with chemotherapy and/or radiation therapy. Ovarian function is most compromised in survivors treated with total body irradiation, abdominal or pelvic irradiation, stem cell transplantation or high doses of alkylating agents. STUDY DESIGN SIZE, DURATION: Longitudinal single-centre cohort study in 192 CCS in Rotterdam, The Netherlands, between 2001 and 2014. PARTICIPANTS/MATERIALS, SETTING, METHODS: Serum AMH levels of 192 adult female CCS were assessed, at least five years after cessation of treatment and at a follow-up visit with a median of 3.2 years (range: 2.1-6.0) later and were compared to the age-based P50 of AMH in healthy controls. MAIN RESULTS AND THE ROLE OF CHANCE: Median AMH levels were below the P50 at both visit 1 (-0.59 µg/L) and at visit 2 (-0.22 µg/L). In women with a sustained ovarian function (AMH > 1.0 µg/L), the decline in AMH is similar to that in the normal population (difference in decline per year: -0.07 µg/L (range: -2.86 to 4.92), P = 0.75). None of the treatment modalities was correlated with a significant acceleration of decline of AMH per year. LIMITATIONS REASONS FOR CAUTION: We selected CCS that visited our late effect outpatient clinic and who had two AMH levels available. It is conceivable that women without any apparent late effects of treatment as well as women with extreme late effects, which might be the ones with the largest impact on ovarian function, could be more likely to be lost to follow-up. However, general characteristics did not differ between the included and excluded patients. WIDER IMPLICATIONS OF THE FINDINGS: While prospective longitudinal research is required to strengthen our findings, they may help physicians to counsel female CCS about their expected reproductive lifespan. STUDY FUNDING/COMPETING INTERESTS: A.L.F.v.d.K., M.M.v.d.H.-E. and S.M.F.P. are supported by FP7-PanCare LIFE. J.S.E.L. has received grants from the following companies (in alphabetical order): Ferring, Merck Serono, Merck Sharp and Dome, Organon, Serono, Shering Plough and Shering. The other authors have no conflicts of interest to declare

    Longitudinal follow-up in female Childhood Cancer Survivors : no signs of accelerated ovarian function loss

    No full text
    STUDY QUESTION: Is the long-term decline of ovarian function, as reflected by a decrease in serum anti-Müllerian hormone (AMH) concentration, accelerated over time in female childhood cancer survivors (CCS) as compared to healthy women of the same age? SUMMARY ANSWER: The median decline of AMH levels in long-term female CCS is not accelerated and similar to that observed in healthy controls. WHAT IS KNOWN ALREADY: Gonadal function is compromised in female CCS treated with chemotherapy and/or radiation therapy. Ovarian function is most compromised in survivors treated with total body irradiation, abdominal or pelvic irradiation, stem cell transplantation or high doses of alkylating agents. STUDY DESIGN SIZE, DURATION: Longitudinal single-centre cohort study in 192 CCS in Rotterdam, The Netherlands, between 2001 and 2014. PARTICIPANTS/MATERIALS, SETTING, METHODS: Serum AMH levels of 192 adult female CCS were assessed, at least five years after cessation of treatment and at a follow-up visit with a median of 3.2 years (range: 2.1-6.0) later and were compared to the age-based P50 of AMH in healthy controls. MAIN RESULTS AND THE ROLE OF CHANCE: Median AMH levels were below the P50 at both visit 1 (-0.59 µg/L) and at visit 2 (-0.22 µg/L). In women with a sustained ovarian function (AMH > 1.0 µg/L), the decline in AMH is similar to that in the normal population (difference in decline per year: -0.07 µg/L (range: -2.86 to 4.92), P = 0.75). None of the treatment modalities was correlated with a significant acceleration of decline of AMH per year. LIMITATIONS REASONS FOR CAUTION: We selected CCS that visited our late effect outpatient clinic and who had two AMH levels available. It is conceivable that women without any apparent late effects of treatment as well as women with extreme late effects, which might be the ones with the largest impact on ovarian function, could be more likely to be lost to follow-up. However, general characteristics did not differ between the included and excluded patients. WIDER IMPLICATIONS OF THE FINDINGS: While prospective longitudinal research is required to strengthen our findings, they may help physicians to counsel female CCS about their expected reproductive lifespan. STUDY FUNDING/COMPETING INTERESTS: A.L.F.v.d.K., M.M.v.d.H.-E. and S.M.F.P. are supported by FP7-PanCare LIFE. J.S.E.L. has received grants from the following companies (in alphabetical order): Ferring, Merck Serono, Merck Sharp and Dome, Organon, Serono, Shering Plough and Shering. The other authors have no conflicts of interest to declare

    An ENO-Based method for second-order equations and application to the control of dike levels

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    This work aims to model the optimal control of dike heights. The control problem leads to so-called Hamilton-Jacobi-Bellman (HJB) variational inequalities, where the dike-increase and reinforcement times act as input quantities to the control problem. The HJB equations are solved numerically with an Essentially Non-Oscillatory (ENO) method. The ENO methodology is originally intended for hyperbolic conservation laws and is extended to deal with diffusion-type problems in this work. The method is applied to the dike optimisation of an island, for both deterministic and stochastic models for the economic growth.Delft Institute of Applied MathematicsElectrical Engineering, Mathematics and Computer Scienc
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