Determining the change in welfare estimates from introducing measurement error in non-linear choice models

Observed and unobserved characteristics of an individual are often used by researchers to explain choices over the provision of environmental goods. One means for identifying what is typically an unobserved characteristic, such as an attitude, is through some data reduction technique, such as factor analysis. However, the resultant variable represents the true attitude with measurement error, and hence, when included into a non-linear choice model, introduces bias in the model. There are well established methods to overcome this issue, which are seldom implemented. In an application to preferences over two water source alternatives for Perth in Western Australia, we use structural equation modeling within a discrete choice model to determine whether welfare measures are significantly impacted by ignoring measurement error in latent attitudes, and the advantage to policy makers from understanding what drives certain attitudes.contingent valuation, attitudes, structural equation modeling, recycled water, Environmental Economics and Policy, Research Methods/ Statistical Methods, Q51, Q53, C13,

Biased estimates in discrete choice models: the appropriate inclusion of psychometric data into the valuation of recycled wastewater

The introduction of measurement bias in parameter estimates into non-linear discrete choice models, as a result of using factor analysis, was identified by Train et al. (1987). They found that the inclusion of factor scores, used to represent relationships amongst like variables, into a subsequent discrete choice models introduced measurement bias as the measurement error associated with each factor score is excluded. This is an issue for non-market valuation given the increase in popularity of including psychometric data, such as primitive beliefs, attitudes and motivations, in willingness to pay estimates. This study explores the relationship between willingness to pay and primitive beliefs through a case study eliciting Perth community values for drinking recycled wastewater. The standard discrete decision model, with sequential inclusion of factor scores, is compared to an equivalent discrete decision model, which corrects for the measurement bias by simultaneously estimating the underlying latent variables using a measurement model. Previous research has focused on the issue of biased parameters. Here we also consider the implications for willingness to pay estimates.discrete choice models, attitudes, factor analysis, measurement models, recycled wastewater,

The use of propofol target-controlled sedation in emergency department procedural sedation

Background Procedural sedation (PS) is commonly required in the Emergency Department (ED). Propofol is a drug commonly used for this. It is administered as an intravenous bolus and adverse events can occur. Target-controlled infusion (TCI) is another way of administering Propofol and may produce less adverse events as the concentration is targeted to be within the therapeutic window. TCI is not currently used in the ED. I assessed the feasibility of running an RCT comparing Propofol TCI vs bolus administration in the ED. Methods I assessed feasibility of a future RCT by; conducting a survey to describe current local PS practice, a time to set up TCI study, a systematic review of rate of adverse events for Propofol TCI vs bolus in PS and a multicentre single arm feasibility study on Propofol TCI in ED sedation. Results 112 respondents completed the survey; most respondents experienced a complication during PS and 79% of respondents were comfortable using Propofol. The difference in median set up time of TCI vs bolus was 143 seconds, approximately half of what participants felt was acceptable. There is a paucity of studies involving TCI in the ED. Twenty-five patients were recruited to the study and results suggests a trend towards fewer respiratory and hypotensive events with Propofol TCI versus other methods of administration. No adverse events were recorded. TCI was deemed acceptable by patients and staff. Conclusion Although results indicate that an RCT to compare the incidence of adverse events in ED procedural sedation would be technically feasible, there may be more efficient approaches to achieving a safe change in practice

Human placental renin-angiotensin system in normotensive and pre-eclamptic pregnancies at high altitude and after acute hypoxia-reoxygenation insult.

A functioning placental renin-angiotensin system (RAS) appears necessary for uncomplicated pregnancy and is present during placentation, which occurs under low oxygen tensions. Placental RAS is increased in pre-eclampsia (PE), characterised by placental dysfunction and elevated oxidative stress. We investigated the effect of high altitude hypoxia on the RAS and hypoxia-inducible factors (HIFs) by measuring mRNA and protein expression in term placentae from normotensive (NT) and PE women who delivered at sea level or above 3100 m, using an explant model of hypoxia-reoxygenation to assess the impact of acute oxidative stress on the RAS and HIFs. Protein levels of prorenin (P = 0.049), prorenin receptor (PRR; P = 0.0004), and angiotensin type 1 receptor (AT1R, P = 0.006) and type 2 receptor (AT2R, P = 0.002) were all significantly higher in placentae from NT women at altitude, despite mRNA expression being unaffected. However, mRNA expression of all RAS components was significantly lower in PE at altitude than at sea level, yet PRR, angiotensinogen (AGT) and AT1R proteins were all increased. The increase in transcript and protein expression of all the HIFs and NADPH oxidase 4 seen in PE compared to NT at sea level was blunted at high altitude. Experimentally induced oxidative stress stimulated AGT mRNA (P = 0.04) and protein (P = 0.025). AT1R (r = 0.77, P < 0.001) and AT2R (r = 0.81, P < 0.001) mRNA both significantly correlated with HIF-1β, whilst AT2R also correlated with HIF-1α (r = 0.512, P < 0.013). Our observations suggest that the placental RAS is responsive to changes in tissue oxygenation: this could be important in the interplay between reactive oxygen species as cell-signalling molecules for angiogenesis and hence placental development and function.HDM is supported by an ERA-EDTA Fellowship (ERA LTF 137-2013).This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1113/JP27104

Border crossings in the African travel narratives of Ibn Battuta, Richard Burton and Paul Theroux

This article compares the representation of African borders in the 14th-century travelogue of Ibn Battuta, the 19th-century travel narrative of Richard Burton and the 21st-century travel writing of Paul Theroux. It examines the mutually constitutive relationship between conceptions of literal territorial boundaries and the figurative boundaries of the subject that ventures across borders in Africa. The border is seen as a liminal zone which paradoxically separates and joins spaces. Accounts of border crossings in travel writing from different periods suggest the historicity and cultural specificity of conceptions of geographical borders, and the way they index the “boundaries” of the subjects who cross them. Tracing the transformations in these conceptions of literal and metaphorical borders allows one to chart the emergence of the dominant contemporary idea of “Africa” as the inscrutable, savage continent

Gender violence in schools: taking the ‘girls-as-victims’ discourse forward

This paper draws attention to the gendered nature of violence in schools. Recent recognition that schools can be violent places has tended to ignore the fact that many such acts originate in unequal and antagonistic gender relations, which are tolerated and ‘normalised’ by everyday school structures and processes. After examining some key concepts and definitions, we provide a brief overview of the scope and various manifestations of gender violence in schools, noting that most research to date has focused on girls as victims of gender violence within a heterosexual context and ignores other forms such as homophobic and girl violence. We then move on to look at a few interventions designed to address gender violence in schools in the developing world and end by highlighting the need for more research and improved understanding of the problem and how it can be addressed

Promoting early presentation of breast cancer in older women during the seasonal influenza vaccination campaign

Background: Older women are at high risk of presenting with late stage of breast cancer, which may be partly because of poor breast cancer awareness. Aims: The aim of this project was to implement and evaluate a new way of delivering the Promoting Early Presentation (PEP) Intervention during flu vaccination appointments in primary care. The PEP intervention is a 1-minute intervention, accompanied by a booklet and delivered by primary care health professionals to provide older women with the knowledge, confidence and skills to present promptly on discovering symptoms of breast cancer. Methods: Health professionals delivered the PEP Intervention to older women at six general practices in South London. We measured changes in breast cancer awareness after the intervention and interviewed practice staff about their experiences of the intervention. Findings: Knowledge of breast symptoms and breast checking was greater in women aged 70+ after the implementation than before. Health professionals’ found the intervention acceptable and feasible to implement. Conclusion: This intervention is a novel way of increasing breast cancer awareness in older women, which could contribute to promoting earlier presentation and diagnosis of breast cancer in the UK

Efficient development and usability testing of decision support interventions for older women with breast cancer

Around a third of breast cancers diagnosed each year in the UK are in women aged 70 years and older. However, there are currently no decision support interventions for older women who have a choice between primary endocrine therapy and surgery followed by adjuvant endocrine therapy (surgery+endocrine therapy), or who can choose whether or not to have chemotherapy following surgery. There is also little evidence-based guidance specifically on the management of these older patients. A large UK cohort study is currently underway to address this lack of evidence and to develop two decision support interventions (DESIs) to facilitate shared decision-making with older women about breast cancer treatments. Here we present the development and initial testing of these two DESIs. An initial prototype DESI was developed for the choice of primary endocrine therapy or surgery+endocrine therapy. Semi-structured interviews with healthy volunteers and patients explored DESI acceptability, usability and utility. A framework approach was used for analysis. A second DESI for the choice of having chemotherapy or not was subsequently developed based on more focused development and testing. Participants (n=22, aged 75-94 years, 64% healthy volunteers, 36% patients) found the primary endocrine therapy/surgery+endocrine therapy DESI acceptable, and contributed to improved wording and illustrations to address misunderstandings. The chemotherapy DESI (tested with 14 participants, aged 70-87 years, 57% healthy volunteers, 43% patients) was mostly understandable, however suggestions for re-wording sections were made. Most participants considered the DESIs helpful, but highlighted the importance of complementary discussions with clinicians. It was possible to use a template DESI to efficiently create a second prototype for a different treatment option (chemotherapy). Both DESIs were acceptable and considered helpful to support/augment consultations. Development of acceptable additional DESIs for similar target populations using simplified methods may be an efficient way to develop future DESIs. Further research is needed to test the effectiveness of the DESIs