The effect of using labelled alternatives in stated choice experiments: an exploration focusing on farmland walking trails in Ireland

Discrete choice experiment data aimed at eliciting the demand for recreational walking trails on farmland in Ireland is used to explore whether some respondents reach their choices solely on the basis of the alternative’s label. To investigate this type of processing strategy, the paper exploits a discrete mixtures approach which encompasses random parameters for the attributes. We find evidence that respondents employ different processing strategies for different alternatives and differences in processing emerge between rural and urban based respondents. Results highlight that model fit and policy conclusions are sensitive to assumptions related to processing strategies among respondentsDiscrete choice experiments, processing strategies, discrete mixtures, rural and urban comparison, outdoor recreation, welfare estimates, Land Economics/Use,

Combining discrete and continuous mixing approaches to accommodate heterogeneity in price sensitivities in environmental choice analysis

Data from a discrete choice experiment aimed at eliciting the demand for recreational walking trails on farmland in the Republic of Ireland is used to explore the consequences of misspecifying the cost coefficient. To enable straightforward calculation of WTP from the distributions of the non-price coefficients, the price coefficient is typically held constant in mixed logit models. This implies that all respondents are equally price sensitive. In this paper we test the validity of this assumption. Our approach is based on a comparison and combination of discrete and continuous mixing approaches (i.e., a mixture of distributions) to uncover the unobserved heterogeneity in price sensitivities. Results from the analysis highlight that model fit and willingness to pay are sensitive to the distributional assumptions used to represent the price coefficient.discrete choice experiments, discrete mixtures, continuous mixtures, mixtures of distributions, price sensitivities, farmland recreation, willing to pay space, Environmental Economics and Policy,

Estimating Linkages between Redfish and Cold Water Coral on the Norwegian Coast

The importance of essential fish habitat in supporting commercial fisheries has received increasing attention in recent years. Bottom trawling is known to cause particularly destructive damage to habitat that is effectively non-renewable, such as cold water corals. This paper applies the production function approach to estimate the link between cold water corals and redfish in Norway. Both the carrying capacity and growth rate of redfish are found to be functions of cold water coral habitat and thus cold water corals can be considered an essential fish habitat. The paper also estimates a facultative relationship between cold water coral and redfish stocks. The essential habitat model shows the best fit to the data. Comparative statics of an essential habitat indicate an approximate annual loss in harvest of between 11 and 29% within the bounds of coral decline estimated by scientists. In terms of policy, our results indicate that essential fish habitat protection should be considered when managing commercially important species.Cold water coral, redfish, production function, habitat-fishery linkages, essential fish habitat, International Development, Research Methods/ Statistical Methods, Q22,

Public access to the countryside: An exploration of the costs and benefits of farmland walking trails

To date, estimates of individuals’ willingness to pay (WTP) for access to the countryside have typically been on sites of special interest such as developed walking routes, public rights of way in specific areas, national parks and forests (see Lockwood and Tracy, 1995; Bennett and Tranter, 1997; Crabtree and MacDonald, 1997; Liston-Heyes and Heyes, 1999; Garrod et al., 1998; Bennett et al., 2003; Buckley et al., 2009; Morris et al., 2009). There has been little if any attempt to derive estimates of individuals’ WTP for the provision of walking trails in the wider countryside at a national level. The present study aims to build on previous work by examining the demand for particular types of walking trails through a nationally representative survey of the Irish population. One further advantage of this research is that apart from valuing walking activities in a generic sense this paper investigates what types of investment in facilities associated with walking trails generate the greatest welfare gains. Furthermore, using a nationally representative survey of the farming population this paper examines farmers’ willingness to participate in a hypothetical walking scheme whereby the general public will be allowed access to specific trails. First by way of background this paper will discuss the situation in relation to access rights to the countryside across a number of countries. Second this paper will outline the research approach which is followed with a discussion of the empirical results. Finally this paper will conclude with a discussion of the papers main findings and their implications for the provision of public access to the countryside.This work was funded by the Department of Agriculture, Fisheries and Food under the Stimulus Funding

The ecological and economic value of cold-water coral ecosystems

Despite the growing scientific literature on cold-water corals (CWC) there appears to be no studies that address the economic values or economic management of the resource. This paper presents an overview of the goods and services of CWC and their associated biodiversity. Use and non-use values associated with CWC are presented, and the methods relevant for assessing their valuation are discussed. The impact of human induced disturbance on CWC is reviewed, in order to indicate how knowledge of CWC values can be used by policy makers in the management of CWC as a habitat and vehicle for biodiversity

BRCA2 polymorphic stop codon K3326X and the risk of breast, prostate, and ovarian cancers

Background: The K3326X variant in BRCA2 (BRCA2*c.9976A>T; p.Lys3326*; rs11571833) has been found to be associated with small increased risks of breast cancer. However, it is not clear to what extent linkage disequilibrium with fully pathogenic mutations might account for this association. There is scant information about the effect of K3326X in other hormone-related cancers. Methods: Using weighted logistic regression, we analyzed data from the large iCOGS study including 76 637 cancer case patients and 83 796 control patients to estimate odds ratios (ORw) and 95% confidence intervals (CIs) for K3326X variant carriers in relation to breast, ovarian, and prostate cancer risks, with weights defined as probability of not having a pathogenic BRCA2 variant. Using Cox proportional hazards modeling, we also examined the associations of K3326X with breast and ovarian cancer risks among 7183 BRCA1 variant carriers. All statistical tests were two-sided. Results: The K3326X variant was associated with breast (ORw = 1.28, 95% CI = 1.17 to 1.40, P = 5.9x10- 6) and invasive ovarian cancer (ORw = 1.26, 95% CI = 1.10 to 1.43, P = 3.8x10-3). These associations were stronger for serous ovarian cancer and for estrogen receptor–negative breast cancer (ORw = 1.46, 95% CI = 1.2 to 1.70, P = 3.4x10-5 and ORw = 1.50, 95% CI = 1.28 to 1.76, P = 4.1x10-5, respectively). For BRCA1 mutation carriers, there was a statistically significant inverse association of the K3326X variant with risk of ovarian cancer (HR = 0.43, 95% CI = 0.22 to 0.84, P = .013) but no association with breast cancer. No association with prostate cancer was observed. Conclusions: Our study provides evidence that the K3326X variant is associated with risk of developing breast and ovarian cancers independent of other pathogenic variants in BRCA2. Further studies are needed to determine the biological mechanism of action responsible for these associations

Associations of common breast cancer susceptibility alleles with risk of breast cancer subtypes in BRCA1 and BRCA2 mutation carriers

Introduction: More than 70 common alleles are known to be involved in breast cancer (BC) susceptibility, and several exhibit significant heterogeneity in their associations with different BC subtypes. Although there are differences in the association patterns between BRCA1 and BRCA2 mutation carriers and the general population for several loci, no study has comprehensively evaluated the associations of all known BC susceptibility alleles with risk of BC subtypes in BRCA1 and BRCA2 carriers. Methods: We used data from 15,252 BRCA1 and 8,211 BRCA2 carriers to analyze the associations between approximately 200,000 genetic variants on the iCOGS array and risk of BC subtypes defined by estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) and triple-negative- (TN) status; morphologic subtypes; histological grade; and nodal involvement. Results: The estimated BC hazard ratios (HRs) for the 74 known BC alleles in BRCA1 carriers exhibited moderate correlations with the corresponding odds ratios from the general population. However, their associations with ER-positive BC in BRCA1 carriers were more consistent with the ER-positive as

Assessing associations between the AURKAHMMR-TPX2-TUBG1 functional module and breast cancer risk in BRCA1/2 mutation carriers

While interplay between BRCA1 and AURKA-RHAMM-TPX2-TUBG1 regulates mammary epithelial polarization, common genetic variation in HMMR (gene product RHAMM) may be associated with risk of breast cancer in BRCA1 mutation carriers. Following on these observations, we further assessed the link between the AURKA-HMMR-TPX2-TUBG1 functional module and risk of breast cancer in BRCA1 or BRCA2 mutation carriers. Forty-one single nucleotide polymorphisms (SNPs) were genotyped in 15,252 BRCA1 and 8,211 BRCA2 mutation carriers and subsequently analyzed using a retrospective likelihood appr

Dolutegravir twice-daily dosing in children with HIV-associated tuberculosis: a pharmacokinetic and safety study within the open-label, multicentre, randomised, non-inferiority ODYSSEY trial

Background: Children with HIV-associated tuberculosis (TB) have few antiretroviral therapy (ART) options. We aimed to evaluate the safety and pharmacokinetics of dolutegravir twice-daily dosing in children receiving rifampicin for HIV-associated TB. Methods: We nested a two-period, fixed-order pharmacokinetic substudy within the open-label, multicentre, randomised, controlled, non-inferiority ODYSSEY trial at research centres in South Africa, Uganda, and Zimbabwe. Children (aged 4 weeks to <18 years) with HIV-associated TB who were receiving rifampicin and twice-daily dolutegravir were eligible for inclusion. We did a 12-h pharmacokinetic profile on rifampicin and twice-daily dolutegravir and a 24-h profile on once-daily dolutegravir. Geometric mean ratios for trough plasma concentration (Ctrough), area under the plasma concentration time curve from 0 h to 24 h after dosing (AUC0–24 h), and maximum plasma concentration (Cmax) were used to compare dolutegravir concentrations between substudy days. We assessed rifampicin Cmax on the first substudy day. All children within ODYSSEY with HIV-associated TB who received rifampicin and twice-daily dolutegravir were included in the safety analysis. We described adverse events reported from starting twice-daily dolutegravir to 30 days after returning to once-daily dolutegravir. This trial is registered with ClinicalTrials.gov (NCT02259127), EudraCT (2014–002632-14), and the ISRCTN registry (ISRCTN91737921). Findings: Between Sept 20, 2016, and June 28, 2021, 37 children with HIV-associated TB (median age 11·9 years [range 0·4–17·6], 19 [51%] were female and 18 [49%] were male, 36 [97%] in Africa and one [3%] in Thailand) received rifampicin with twice-daily dolutegravir and were included in the safety analysis. 20 (54%) of 37 children enrolled in the pharmacokinetic substudy, 14 of whom contributed at least one evaluable pharmacokinetic curve for dolutegravir, including 12 who had within-participant comparisons. Geometric mean ratios for rifampicin and twice-daily dolutegravir versus once-daily dolutegravir were 1·51 (90% CI 1·08–2·11) for Ctrough, 1·23 (0·99–1·53) for AUC0–24 h, and 0·94 (0·76–1·16) for Cmax. Individual dolutegravir Ctrough concentrations were higher than the 90% effective concentration (ie, 0·32 mg/L) in all children receiving rifampicin and twice-daily dolutegravir. Of 18 children with evaluable rifampicin concentrations, 15 (83%) had a Cmax of less than the optimal target concentration of 8 mg/L. Rifampicin geometric mean Cmax was 5·1 mg/L (coefficient of variation 71%). During a median follow-up of 31 weeks (IQR 30–40), 15 grade 3 or higher adverse events occurred among 11 (30%) of 37 children, ten serious adverse events occurred among eight (22%) children, including two deaths (one tuberculosis-related death, one death due to traumatic injury); no adverse events, including deaths, were considered related to dolutegravir. Interpretation: Twice-daily dolutegravir was shown to be safe and sufficient to overcome the rifampicin enzyme-inducing effect in children, and could provide a practical ART option for children with HIV-associated TB