A Method to Estimate the Magnitude of "Hypothetical Bias" in Stated Preference Surveys of Passive-use Value

This paper proposes a method by which estimates of hypothetical willingness to pay for public goods with passive-use value can be compared with actual willingness to pay inferred from aggregate voting and tax liability data.

Calibration of Stated Willingness to Pay for Public Goods with Voting and Tax Liability Data: Provision of Landscape Amenities in Switzerland

Controversy remains over the degree of hypothetical bias in contingent valutation method (CVM) estimates of values for public goods, especially for public goods with significant passive-use values. This paper uses an 'indifferent voter' approach to calibrate stated WTP for a proposed public good increase with actual WTP implied by voting and tax liability data. Our data are from a CVM survey and an actual voting decision on propositions to increase public funds for landscape amenities protection in the canton of Zurich, Switzerland.contingent valuation; indifferent voter; median voter theorem; referendum;valuation

A BIOTIC CONTROL PERSPECTIVE ON NITRATE CONTAMINATION OF GROUNDWATER FROM AGRICULTURAL PRODUCTION

Agronomists consider the continuity and nutrient capturing properties of cover crops as important determinants of nutrient cycling in agricultural systems. Managing for these biotic control functions can help limit nutrient loss and groundwater contamination between main crop harvests. This simulation study highlights the potential role of cover crop management in a welfare economics framework. The objective is to find the optimal combination of nutrient input to the main crop, the extent of off-season cover crops, and crop functional diversity to maximize the sum of benefits from agricultural production and groundwater protection.Crop Production/Industries,

Contingent valuation and real referendum behaviour,

This paper compares contingent values for a hypothetical landscape protection programme with respondents’ voting behaviour in an actual referendum. We use the example of a proposed increase of expenditures for landscape protection in the canton of Zurich, Switzerland. In particular we examine (i) CVM bid magnitudes of the different voter groups, (ii) relationships between qualitative response categories, (iii) consistency of responses assuming tax increases are known, and (iv) associations with socio-economic characteristics. Results suggest a strong upward bias of hypothetical values, possibly indicating that many respondents failed to realistically consider their budget constraints in the hypothetical choice situation.Contingent valuation; external validity; public goods; referendum voting

High resolution images of P/Tempel 1 and P/Tempel 2 constructed from IRAS survey data

Infrared images of P/Tempel 1 and P/Tempel 2 were constructed from IRAS survey data using a computer algorithm based on the Maximum Correlation Method for Image Construction (Aumann et al, 1990). The resulting images are of sufficiently high quality and resolution to delineate coma and tail morphology, and permit accurate photometry of the total dust complex. Comparisons of the infrared colors and photometric profiles of Tempel 1 and Tempel 2 at similar heliocentric distances show that the grains produced by the two comets are quite similar in radiometric and dynamic properties. Tempel 1 is found to produce about 30 percent more dust in its coma and tail than Tempel 2. The comae of Tempel 1 and Tempel 2 are expanding with mean velocities of 5.8 plus or minus 0.07 and 6.1 plus or minus 0.17 m/sec respectively, indicative of the ejection of large grains. The IRAS cataloged infrared fluxes (Walker, 1986) are found to be underestimated by as much as a factor of three for the comets. Therefore, it is essential to create images of the comets to obtain meaningful IRAS photometry

A radiation hybrid framework map of bovine chromosome 13

In this paper we present a 5000-rad radiation hybrid framework map of bovine chromosome 13 (BTA13) containing 13 loci, including five conserved genes and eight polymorphic microsatellites. All framework markers are ordered with odds greater than 1000:1. Furthermore, we present a comprehensive map of BTA13 integrating 11 genes and 16 microsatellites. The proposed order is in general agreement with the recently published medium-density linkage maps. A model of five blocks of genes with conserved order between human, mouse and cattle is presente

Impact of the implantable cardioverter-defibrillator on rehospitalizations

Patients who survive out-of-hospital ventricular tachycardia or ventricular fibrillation are at risk of sudden cardiac death and often return to hospital after initial discharge. The frequency and duration of readmittance to hospital are not well known. Thus, the purpose of this study was to evaluate the impact of the implantable cardioverter defibrillator on frequency and duration of hospitalizations. Methods Between 1989 and 1993, 38 consecutive patients who had drug-refractory ventricular tachyarrhythmias were selected for the study. A total of 38 patients were implanted with the implantable cardioverter-defibrillator in accordance with the guidelines of the European Society of Cardiology. This analysis includes 35 of the 38 patients (92%). All hospitalizations which occurred one year before and one year after were studied. Clinical information for all patients was obtained by consulting medical records and by interviewing personal general practitioners. Results The annual number of hospitalizations before and after implantation of the implantable cardioverter defibrillator was, respectively, 3·28 ± 2 hospitalizations/patient/year and 0·88 ± 1·23 hospitalizations/patient/year (P<0·05). Before implantation of the implantable cardioverter-defibrillator, patients were hospitalized a mean of 32·94 plusmn; 24·18 days/patient/year and after, 9·31 ± 32·14 days/patient/year (P<0·05). The number of hospitalizations for cardiac reasons decreased by 90%. Before implantation, the most frequent cause was ventricular tachyarrhythmia (47 hospitalizations for ventricular tachycardia and eight for ventricular fibrillation), while after implantation, it was as a result of the shock from the implantable cardioverter defibrillator (II hospitalizations). The number of hospitalizations for non-cardiac reasons were similar in the two time periods. Of the 35 patients, 26 (74%) had at least one appropriate successful ventricular tachycardia interrupted by the implantable cardioverter-defibrillator, while 17 patients (49%) had their ventricular fibrillation terminated. There is a significant difference in the rate of hospitalizations to intensive care units (ICU) between the two periods. Before implantation, 30% of hospital days were spent in the ICU, with 3% after. Conclusions This study documents that the implantable cardioverter-defibrillator not only reduces the frequency and duration of hospital stays, but reduces admissions to the more expensive units in hospital. Taking into account the reduction in hospitalizations, the payback period for the implantation of an implantable cardioverter-defibrillator is 19 months. (Eur Heart J 1996; 17: 1565-1571

Revealing the Changing Spatial Structure of Cities from Human Activity Patterns

Identifying changes in the spatial structure of cities is a prerequisite for the development and validation of adequate planning strategies. Nevertheless, current methods of measurement are becoming ever more challenged by the highly diverse and intertwined ways of how people actually make use of urban space. Here, we propose a new quantitative measure for the centrality of locations, taking into account not only the numbers of people attracted to different locations, but also the diversity of the activities they are engaged in. This ‘centrality index’ allows for the identification of functional urban centres and for a systematic tracking of their relative importance over time, thus contributing to our understanding of polycentricity. We demonstrate the proposed index using travel survey data in Singapore for different years between 1997 and 2012. It is shown that, on the one hand, the city-state has been developing rapidly towards a polycentric urban form that compares rather closely with the official urban development plan. On the other hand, however, the downtown core has strongly gained in its importance, and this can be partly attributed to the recent extension of the public transit system

Impact of the implantable cardioverter-defibrillator on rehospitalizations

Patients who survive out-of-hospital ventricular tachycardia or ventricular fibrillation are at risk of sudden cardiac death and often return to hospital after initial discharge. The frequency and duration of readmittance to hospital are not well known. Thus, the purpose of this study was to evaluate the impact of the implantable cardioverter defibrillator on frequency and duration of hospitalizations. METHODS: Between 1989 and 1993, 38 consecutive patients who had drug-refractory ventricular tachyarrhythmias were selected for the study. A total of 38 patients were implanted with the implantable cardioverter-defibrillator in accordance with the guidelines of the European Society of Cardiology. This analysis includes 35 of the 38 patients (92%). All hospitalizations which occurred one year before and one year after were studied. Clinical information for all patients was obtained by consulting medical records and by interviewing personal general practitioners. RESULTS: The annual number of hospitalizations before and after implantation of the implantable cardioverter-defibrillator was, respectively, 3.28 +/- 2.38 hospitalizations/ patient/year and 0.88 +/- 1.23 hospitalizations/patient/year (P &lt; 0.05). Before implantation of the implantable cardioverter-defibrillator, patients were hospitalized a mean of 32.94 +/- 24.18 days/patient/year and after, 9.31 +/- 32.14 days/patient/year (P &lt; 0.05). The number of hospitalizations for cardiac reasons decreased by 90%. Before implantation, the most frequent cause was ventricular tachyarrhythmia (47 hospitalizations for ventricular tachycardia and eight for ventricular fibrillation), while after implantation, it was as a result of the shock from the implantable cardioverter-defibrillator (11 hospitalizations). The number of hospitalizations for non-cardiac reasons were similar in the two time periods. Of the 35 patients, 26 (74%) had at least one appropriate successful ventricular tachycardia interrupted by the implantable cardioverter-defibrillator, while 17 patients (49%) had their ventricular fibrillation terminated. There is a significant difference in the rate of hospitalizations to intensive care units (ICU) between the two periods. Before implantation, 30% of hospital days were spent in the ICU, with 3% after. CONCLUSIONS: This study documents that the implantable cardioverter-defibrillator not only reduces the frequency and duration of hospital stays, but reduces admissions to the more expensive units in hospital. Taking into account the reduction in hospitalizations, the payback period for the implantation of an implantable cardioverter-defibrillator is 19 months