Choice of season cards in public transport: a study of a Stated Preference experiment

This paper studies a Stated Preference (SP) experiment on the choice of type of (Rail) season card, conducted among current Dutch Railways season cardholders. They were asked to choose from the following three alternatives: (1) an unrestricted season card, (2) a cheaper season card with peak travel and travel frequency restrictions, and (3) not buying a season card. Multinomial logit (MNL), nested logit and mixed logit models are used to analyse their choices. It is found that MNL underestimates the price sensitivities (as measured by the price elasticities) of the respondents and overestimates their Willingnessto- Pay (WTP) for reductions in the restrictions. The mixed logit estimation shows that there are (unobserved) differences in the marginal utilities of the price of the card (response heterogeneity), and the utility of owning a season card (preference heterogeneity). In the Netherlands a large share of commuters and business travellers receive travel cost compensation from their employer. However, empirical studies often do not control for the effect of travel cost compensation. We find, as expected, that travel cost compensation has a large impact on the price sensitivities and choices of the respondents

On chain domains, prime rings and torsion preradicals.

Abstract available in pdf file

Concrete resource analysis of the quantum linear system algorithm used to compute the electromagnetic scattering cross section of a 2D target

We provide a detailed estimate for the logical resource requirements of the quantum linear system algorithm (QLSA) [Phys. Rev. Lett. 103, 150502 (2009)] including the recently described elaborations [Phys. Rev. Lett. 110, 250504 (2013)]. Our resource estimates are based on the standard quantum-circuit model of quantum computation; they comprise circuit width, circuit depth, the number of qubits and ancilla qubits employed, and the overall number of elementary quantum gate operations as well as more specific gate counts for each elementary fault-tolerant gate from the standard set {X, Y, Z, H, S, T, CNOT}. To perform these estimates, we used an approach that combines manual analysis with automated estimates generated via the Quipper quantum programming language and compiler. Our estimates pertain to the example problem size N=332,020,680 beyond which, according to a crude big-O complexity comparison, QLSA is expected to run faster than the best known classical linear-system solving algorithm. For this problem size, a desired calculation accuracy 0.01 requires an approximate circuit width 340 and circuit depth of order $10^{25}$ if oracle costs are excluded, and a circuit width and depth of order $10^8$ and $10^{29}$, respectively, if oracle costs are included, indicating that the commonly ignored oracle resources are considerable. In addition to providing detailed logical resource estimates, it is also the purpose of this paper to demonstrate explicitly how these impressively large numbers arise with an actual circuit implementation of a quantum algorithm. While our estimates may prove to be conservative as more efficient advanced quantum-computation techniques are developed, they nevertheless provide a valid baseline for research targeting a reduction of the resource requirements, implying that a reduction by many orders of magnitude is necessary for the algorithm to become practical.Comment: 37 pages, 40 figure

Effective Kan fibrations in simplicial sets

We introduce the notion of an effective Kan fibration, a new mathematical structure that can be used to study simplicial homotopy theory. Our main motivation is to make simplicial homotopy theory suitable for homotopy type theory. Effective Kan fibrations are maps of simplicial sets equipped with a structured collection of chosen lifts that satisfy certain non-trivial properties. This contrasts with the ordinary, unstructured notion of a Kan fibration. We show that fundamental properties of Kan fibrations can be extended to explicit constructions on effective Kan fibrations. In particular, we give a constructive (explicit) proof showing that effective Kan fibrations are stable under push forward, or fibred exponentials. This is known to be impossible for ordinary Kan fibrations. We further show that effective Kan fibrations are local, or completely determined by their fibres above representables. We also give an (ineffective) proof saying that the maps which can be equipped with the structure of an effective Kan fibration are precisely the ordinary Kan fibrations. Hence implicitly, both notions still describe the same homotopy theory. By showing that the effective Kan fibrations combine all these properties, we solve an open problem in homotopy type theory. In this way our work provides a first step in giving a constructive account of Voevodsky's model of univalent type theory in simplicial sets.Comment: 170 page

Comorbidities and malignancies negatively affect survival in myelodysplastic syndromes:A population-based study

Population-based studies that contain detailed clinical data on patients with myelodysplastic syndrome (MDS) are scarce. This study focused on the real-world overall survival (OS) of MDS patients in association with comorbidities, specifically malignancies. An observational population-based study using the HemoBase registry was performed, including all patients with MDS diagnosed between 2005 and 2017 in Friesland, a Dutch province. Detailed information about diagnosis, patient characteristics, previous treatment of malignancies, and comorbidities according to the Charlson Comorbidity Index (CCI) was collected from electronic health records. Patients were followed up until June 2019. Kaplan-Meier plots and Cox regression analyses were used to study survival differences. In the 291 patients diagnosed with MDS, the median OS was 25.3 months (95% confidence interval [CI], 20.3-30.2). OS was significantly better for patients with CCI score <4, age <65 years, female sex, and low-risk MDS. Fifty-seven patients (20%) had encountered a prior malignancy (excluding nonmelanoma skin cancer), and a majority (38 patients; 67%) were therapy related. Both therapy-related and secondary MDSs were associated with worse OS (hazard ratio, 1.51; 95% CI, 1.02-2.23 and 1.58; 95% CI, 0.95-2.65, respectively), as compared with de novo MDS patients (P = .04). Patients in remission at time of MDS diagnosis had a similar median OS compared with patients with de novo MDS (25.5 vs 28.3 months). This population-based study involving all newly diagnosed MDS patients over a 13-year period in Friesland showed that multiple comorbidities, including previous malignancies, are associated with shorter OS. OS was not related to the use of radiotherapy or chemotherapy

A Role for CETP TaqIB Polymorphism in Determining Susceptibility to Atrial Fibrillation: A Nested Case Control Study

Studies investigating the genetic and environmental characteristics of atrial fibrillation (AF) may provide new insights in the complex development of AF. We aimed to investigate the association between several environmental factors and loci of candidate genes, which might be related to the presence of AF. A nested case-control study within the PREVEND cohort was conducted. Standard 12 lead electrocardiograms were recorded and AF was defined according to Minnesota codes. For every case, an age and gender matched control was selected from the same population (n = 194). In addition to logistic regression analyses, the multifactor-dimensionality reduction (MDR) method and interaction entropy graphs were used for the evaluation of gene-gene and gene-environment interactions. Polymorphisms in genes from the Renin-angiotensin, Bradykinin and CETP systems were included

Health-related quality of life and cardiac rehabilitation: Does body mass index matter?

OBJECTIVE: To investigate the relation between body mass index class and changes in health-related quality of life in patients participating in cardiac rehabilitation. DESIGN: Prospective cohort study. PATIENTS: A total of 503 patients with acute coronary syndrome. METHODS: Data from the OPTICARE trial were used, in which health-related quality of life was measured with the MacNew Heart Disease HRQOL Instrument at the start, directly after, and 9 months after completion of cardiac rehabilitation. Patients were classed as normal weight, overweight, or obese. RESULTS: During cardiac rehabilitation, global health-related quality of life improved in patients in all classes of body mass index. Patients classed as overweight had a significantly greater improvement in social participation than those classed as normal weight (5.51-6.02 compared with 5.73-5.93, respectively; difference in change 0.30, p = 0.025). After completion of cardiac rehabilitation, health-related quality of life continued to improve similarly in patients in all classes of body mass index. CONCLUSION: Health-related quality of life improved during cardiac rehabilitation in patients of all classes of body mass index. Patients classed as overweight showed the greatest improvement. The beneficial effects were maintained during extended follow-up after completion of cardiac rehabilitation

Physical activity and sedentary behaviour changes during and after cardiac rehabilitation:Can patients be clustered?

Objective: To identify clusters of patients according to changes in their physical behaviour during and after cardiac rehabilitation, and to predict cluster membership. Methods: The study included 533 patients (mean age 57.9 years; 18.2% females) with a recent acute coronary syndrome who participated in a 12-week multi-disciplinary cardiac rehabilitation programme, within a cohort study design. Physical behaviour (light physical activity, moderate-to vigorous physical activity, step count, and sedentary behaviour) was measured using accelerometry at 4 time-points. To identify clusters of patients according to changes in physical behaviour during and after cardiac rehabilitation, latent class trajectory modelling was applied. Baseline factors to predict cluster membership were assessed using multinomial logistic regression. Results: During and after cardiac rehabilitation, 3 separate clusters were identified for all 4 physical behaviour outcomes: patients with steady levels (comprising 68–83% of the patients), and improving (6–21%) or deteriorating (4–23%) levels. Main predictor for membership to a specific cluster was baseline physical behaviour. Patients with higher starting physical behaviour were more likely to be a member of clusters with deteriorating levels. Conclusion: Separate clusters of physical behaviour changes during and after cardiac rehabilitation could be identified. Clusters were mainly distinguis-hed by baseline physical behaviour level.</p

Physical activity and sedentary behaviour changes during and after cardiac rehabilitation:Can patients be clustered?

Objective: To identify clusters of patients according to changes in their physical behaviour during and after cardiac rehabilitation, and to predict cluster membership. Methods: The study included 533 patients (mean age 57.9 years; 18.2% females) with a recent acute coronary syndrome who participated in a 12-week multi-disciplinary cardiac rehabilitation programme, within a cohort study design. Physical behaviour (light physical activity, moderate-to vigorous physical activity, step count, and sedentary behaviour) was measured using accelerometry at 4 time-points. To identify clusters of patients according to changes in physical behaviour during and after cardiac rehabilitation, latent class trajectory modelling was applied. Baseline factors to predict cluster membership were assessed using multinomial logistic regression. Results: During and after cardiac rehabilitation, 3 separate clusters were identified for all 4 physical behaviour outcomes: patients with steady levels (comprising 68–83% of the patients), and improving (6–21%) or deteriorating (4–23%) levels. Main predictor for membership to a specific cluster was baseline physical behaviour. Patients with higher starting physical behaviour were more likely to be a member of clusters with deteriorating levels. Conclusion: Separate clusters of physical behaviour changes during and after cardiac rehabilitation could be identified. Clusters were mainly distinguis-hed by baseline physical behaviour level.</p