Random error in willingness to pay measurement: A multiple indicators, latent variable approach to the reliability of contingent values

The reliability of measurement refers to unsystematic error in observed responses. Investigations of the prevalence of random error in stated estimates of willingness to pay (WTP) are important to an understanding of why tests of validity in CV can fail. However, published reliability studies have tended to adopt empirical methods that have practical and conceptual limitations when applied to WTP responses. This contention is supported in a review of contingent valuation reliability studies that demonstrate important limitations of existing approaches to WTP reliability. It is argued that empirical assessments of the reliability of contingent values may be better dealt with by using multiple indicators to measure the latent WTP distribution. This latent variable approach is demonstrated with data obtained from a WTP study for stormwater pollution abatement. Attitude variables were employed as a way of assessing the reliability of open-ended WTP (with benchmarked payment cards) for stormwater pollution abatement. The results indicated that participants' decisions to pay were reliably measured, but not the magnitude of the WTP bids. This finding highlights the need to better discern what is actually being measured in VVTP studies, (C) 2003 Elsevier B.V. All rights reserved.

Nutrient partitioning during treatment of tuberculosis: gain in body fat mass but not in protein mass

Background: Tuberculosis is an important cause of wasting. The functional consequences of wasting and recovery may depend on the distribution of lost and gained nutrient stores between protein and fat masses. Objective: The goal was to study nutrient partitioning, ie, the proportion of weight change attributable to changes in fat mass (FM) versus protein mass (PM), during anti mycobacterial treatment. Design: Body-composition measures were made of 21 men and 9 women with pulmonary tuberculosis at baseline and after 1 and 6 mo of treatment. All subjects underwent dual-energy X-ray absorptiometry and deuterium bromide dilution tests, and a four-compartment model of FM, total body water (TBW), bone minerals (BM), and PM was derived. The ratio of PM to FM at any time was expressed as the energy content (p-ratio). Changes in the p-ratio were related to disease severity as measured by radiologic criteria. Results: Patients gained 10% in body weight (P < 0.001) from baseline to month 6. This was mainly due to a 44% gain in FM (P < 0.001); PM, BM, and TBW did not change significantly. Results were similar in men and women. The p-ratio decreased from baseline to month 1 and then fell further by month 6. Radiologic disease severity was not correlated with changes in the p-ratio. Conclusions: Microbiological cure of tuberculosis does not restore PM within 6 mo, despite a strong anabolic response. Change in the p-ratio is a suitable parameter for use in studying the effect of disease on body composition because it allows transformation of such effects into a normal distribution across a wide range of baseline proportion between fat and protein mass.

Assessment of volume depletion in children with malaria

Background The degree of volume depletion in severe malaria is currently unknown, although knowledge of fluid compartment volumes can guide therapy. To assist management of severely ill children, and to test the hypothesis that volume changes in fluid compartments reflect disease severity, we measured body compartment volumes in Gabonese children with malaria. Methods and Findings Total body water volume (TBW) and extracellular water volume (ECW) were estimated in children with severe or moderate malaria and in convalescence by tracer dilution with heavy water and bromide, respectively. Intracellular water volume (ICW) was derived from these parameters. Bioelectrical impedance analysis estimates of TBW and ECW were calibrated and bioelectrical impedance analysis measurements were taken daily against dilution methods, until discharge. Sixteen children had severe and 19 moderate malaria. Severe childhood malaria was associated with depletion of TBW (mean [SD] of 37 [33] ml/kg, or 6.7% [6.0%]) relative to measurement at discharge. This is defined as mild dehydration in other conditions. ECW measurements were normal on admission in children with severe malaria and did not rise in the first few days of admission. Volumes in different compartments (TBW, ECW, and ICW) were not related to hyperlactataemia or other clinical and laboratory markers of disease severity. Moderate malaria was not associated with a depletion of TBW. Conclusions Significant hypovolaemia does not exacerbate complications of severe or moderate malaria. As rapid rehydration of children with malaria may have risks, we suggest that fluid replacement regimens should aim to correct fluid losses over 12-24 h.

Satisfaction with medical rehabilitation after spinal cord injury

Study Design. Retrospective Objective. To predict satisfaction with medical rehabilitation. Summary of Background Data. While spinal cord injury (SCI) patient satisfaction with life and community services has been investigated, satisfaction with medical rehabilitation has not. Methods. Information submitted to the Uniform Data System for Medical Rehabilitation ( 1998 - 2001) by 134 hospitals/rehabilitation facilities in the United States (n = 6,205 patients with SCI) was examined. Predictors were sociodemographic variables, Case Mix Groupings (CMG) ( 401 - 505, 5001), length of stay, rehospitalization, followup therapy, and health maintenance. Satisfaction was assessed at a mean of 92.2 days (SD 11.9 days) postdischarge. Data were analyzed according to who reported the outcome ( patient, n = 3,858 or family/other, n = 1,869). Statistical modeling was conducted using logistic regression. Results. High overall satisfaction was reported (94%). Significant predictors for the patient report data were CMG and rehospitalization. Compared with CMG 5001 ( short stay,

The late effects of poliomyelitis in Queensland

This paper reports an investigation of new health problems reported by Queensland residents with a prior history of poliomyelitis. 126 people with a past history of paralytic poliomyelitis were recruited from the waiting list for the trial Post Polio Clinic at Queen Elizabeth II Hospital, Brisbane. A self-administered postal questionnaire was used to examine a number of variables including acute poliomyelitis histories; presence, duration and severity of new symptoms consistent with the late effects of poliomyelitis; changes in functional status between the maximal recovery period and the time of the survey and the impact of post-polio symptoms on lifestyle and employment. The most frequent new symptoms reported were muscle weakness (87 per cent), unusual tiredness (79 per cent), joint pain (79 per cent), muscle pain (61 per cent) and muscle cramps (71 per cent). Subjects reported an increased reliance on assistive devices and a decreased level of independence with activities of daily living, particularly with mobility-related tasks. Eight three per cent of subjects had made lifestyle changes as a result of post-polio symptoms and 67 per cent of those subjects in the workforce reported making changes to their employment, such as reduced hours of work. (author abstract)

Communication in coral reef fish: the role of ultraviolet colour patterns in damselfish territorial behaviour

Many coral reef fish possess ultraviolet (UV) colour patterns. The behavioural significance of these patterns is poorly understood and experiments on this issue have not been reported for free-living reef fish in their natural environment. The damselfish Pomacentrus amboinensis has UV facial patterns, and spectroradiometric ocular media measurements show that it has the potential for UV vision. To test the potential behavioural significance of the UV patterns, I studied the response of males, in natural territories on the reef and in aquaria, to two conspecific intruders, one presented in a UV-transmitting (UV+) container and the other in a UV-absorbing (UV-) one. Territory owners attacked intruders viewed through UV+ filters significantly more often and for longer than intruders viewed through the UV- filter. In general, the results of the field experiment confirmed those of the laboratory experiment. The results support the hypothesis that P. amboinensis males are sensitive to UV light and that reflectance patterns, which appear in high contrast only in UV, modulate the level of aggressive behaviour. A recent survey showed that many predatory fish may not have UV vision and the use of UV colours in select species of reef fish may therefore serve as a 'private communication channel'. (C) 2004 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Australian occupational therapists' use of an online evidence-based practice database (OTseeker)

Introduction: Online databases can support the implementation of evidence-based practice by providing easy access to research. OTseeker (www.otseeker.com), an electronic evidence database, was introduced in 2003 to assist occupational therapists to locate and interpret research. Objectives: This study explored Australian occupational therapists' use and perceptions of OTseeker and its impact on their knowledge and practice. Methods: A postal survey questionnaire was distributed to two samples: (i) a proportionate random sample of 400 occupational therapists from all states and territories of Australia, and (ii) a random sample of occupational therapists working in 95 facilities in two Australian states (Queensland and New South Wales). Results: The questionnaire was completed by 213 participants. While most participants (85.9%) had heard of OTseeker, only 103 (56.6%) had accessed it, with lack of time being the main reason for non-use. Of the 103 participants who had accessed OTseeker, 68.9% had done so infrequently, 63.1% agreed that it had increased their knowledge and 13.6% had changed their practice after accessing information on OTseeker. Conclusion: Despite OTseeker being developed to provide occupational therapists with easy access to research, lack of time was the main reason why over half of the participants in this study had not accessed it. This exploratory research suggests, however, that there is potential for the database to influence occupational therapists' knowledge and practice about treatment efficacy through access to the research literature.

Perceived academic performance, self-esteem and locus of control as indicators of need for assessment of adolescent suicide risk: implications for teachers

Introduction: There is currently a need for research into indicators that could be used by non-clinical professionals working with young people, to inform the need for referral for further clinical assessment of those at risk of suicide. Method: Participants of this repeated measures longitudinal study, were 2603, 2485, and 2246 school students aged 13, 14, and 15, respectively, from 27 South Australian Schools. Results: Perceived academic performance, self-esteem and locus of control are significantly associated with suicidality. Further, logistic regression of longitudinal results suggests that perceived academic performance, over and above self-esteem and locus of control, in some instances, is a good long-term predictor of suicidality. (C) 2004 Published by Elsevier Ltd. on behalf of The Association for Professionals in Services for Adolescents.

Client fish ectoparasite loads and cleaner shrimp Urocaridella sp c hunger levels affect cleaning behaviour

Cleaning is a classic example of mutualism and determining the factors that maintain the balance between the costs and benefits for mutualist partners can assist our understanding of how cleaning relationships are maintained. Optimal foraging theory suggests two factors that might help to maintain the relationship between cleaners and their clients: client ectoparasite load and cleaner hunger levels. The ecological relevance and importance of foraging by cleaner fish in marine systems has been demonstrated repeatedly, yet there is little information available on this behaviour in cleaner shrimp. To determine whether cleaner shrimp base their choice of client fish on food patch quality (i.e. client fish ectoparasite load) we offered the yellow-beaked cleaner shrimp Urocaridella sp. c a choice of parasitized and unparasitized rock cods, Cephalopholis cyanostigma. To determine whether cleaner shrimp hunger levels influence cleaning time, we manipulated hunger levels in Urocaridella sp. c and examined their behaviour towards parasitized client fish. Cleaner shrimp preferred parasitized to unparasitized client fish and food-deprived cleaner shrimp cleaned parasitized rock cods more frequently than satiated cleaner shrimp did. Therefore, variations in client fish ectoparasite load and cleaner shrimp hunger level are two factors that affect the balance in this mutualism. Finally, our results meet some of the assumptions of biological market theory, a framework used to understand cooperative interactions, and thus this framework is suggested for future studies on this cleaning system.

Temperature influences the coercive mating and swimming performance of male eastern mosquitofish

Although the functional consequences of temperature variation have been examined for a wide range of whole-animal performance traits, the implications of thermal variation for reproductive behaviour or performance are poorly known. I examined the acute effects of temperature on the mating behaviour and swimming performance of male eastern mosquitofish, Gambusia holbrooki, which rely on a coercive strategy to obtain matings and are routinely exposed to wide daily temperature fluctuations. Males showed reproductive behaviours across the entire test temperature range of 14-38 degrees C, representing one of the widest reproductively active temperature ranges for any ectotherm. Both the time spent in pursuit of females and the total number of mating attempts increased with temperature to a plateau that started at approximately 22-26 degrees C. However, males maintained a constant level of copulations at 18-34 degrees C, the temperature range they routinely experience in southeast Queensland. In contrast, maximum swimming performance and approach speeds during copulations were highly thermally dependent across this temperature range. Thus, acute temperature variation has important fitness implications for male G. holbrooki, but mating performance was significantly limited only at extreme temperatures. (c) 2005 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Length of Stay, Discharge Destination, and Functional Improvement: Utility of the Australian National Subacute and Nonacute Patient Casemix Classification

Background and Purpose - Although implemented in 1998, no research has examined how well the Australian National Subacute and Nonacute Patient (AN-SNAP) Casemix Classification predicts length of stay (LOS), discharge destination, and functional improvement in public hospital stroke rehabilitation units in Australia. Methods - 406 consecutive admissions to 3 stroke rehabilitation units in Queensland, Australia were studied. Sociode-mographic, clinical, and functional data were collected. General linear modeling and logistic regression were used to assess the ability of AN-SNAP to predict outcomes. Results - AN-SNAP significantly predicted each outcome. There were clear relationships between the outcomes of longer LOS, poorer functional improvement and discharge into care, and the AN-SNAP classes that reflected poorer functional ability and older age. Other predictors included living situation, acute LOS, comorbidity, and stroke type. Conclusions - AN-SNAP is a consistent predictor of LOS, functional change and discharge destination, and has utility in assisting clinicians to set rehabilitation goals and plan discharge.

Discrepancy between older clients' ability to read and comprehend and the reading level of written educational materials used by occupational therapists

OBJECTIVE. The match between the reading level of occupational therapy education materials and older clients' reading ability and comprehension was determined. The sociodemographic and literacy characteristics that influenced clients' reading ability and comprehension were investigated. METHOD. The reading level of 110 written education materials (handouts, brochures, and information leaflets), distributed to older clients (65 years of age and older) by occupational therapists working in Queensland hospitals, was analyzed using the Flesch formula. The reading ability of 214 older persons (mean age 77 years, 63% female) was assessed using the Rapid Estimate of Adult Literacy in Medicine. Participants' comprehension of information of increasing reading difficulty was measured using the Cloze procedure. RESULTS. The written materials required a mean reading level between the ninth and tenth grades. Participants' mean reading ability was seventh to eighth grade. Therefore some materials may have been too difficult for participants to read and understand. Participants with a managerial or professional or clerical background (p = 0.001) and those who perceived they read well (p = 0.001) had a significantly higher reading ability, Older age was significantly related to poorer comprehension (p = 0.018), with participants 75 years of age and over having a mean comprehension score of 25.6 compared to 30.3 for those 65 to 74 years of age. CONCLUSION. Occupational therapists must analyze the reading level of the written education materials they develop for and use with clients by applying readability formulas. There should be a match between the reading level of written materials and clients' reading ability. Clients' reading ability may be assessed informally by discussing years of education and literacy habits or formally using reading assessments. Content and design characteristics should be considered when developing written education materials for clients.

Dietary supplementation of vitamin E and -lipoic acid upregulates cell growth and signaling genes in rat myocardium

The efficacy of antioxidant supplementation in the prevention of cardiovascular disease appears equivocal, however the use of more potent antioxidant combinations than those traditionally used may exert a more positive effect. We have shown previously that supplementation of vitamin E and α-lipoic acid increases cardiac performance during post-ischemia reperfusion in older rats and increases Bcl-2 levels in endothelial cells. The purpose of this study was to examine the effects of vitamin E and α-lipoic acid supplementation on myocardial gene expression with a view to determine their mechanism of action. Young male rats received either a control (n=7) or vitamin E and α-lipoic acid supplemented diet (n=8) for 14 weeks. RNA from myocardial tissue was then amplified and samples were pooled within groups and competitively hybridized to 5K oligonucleotide rat microarrays. The relative expression of each gene was then compared to the control sample. Animals that received the antioxidant-supplemented diet exhibited upregulation (>1.5×) of 13 genes in the myocardium with 2 genes downregulated.� �Upregulated genes include those involved in cell growth and maintenance (LynB, Csf1r, Akt2, Tp53), cell signaling (LynB, Csf1r) and signal transduction (Pacsin2, Csf1r). Downregulated genes encode thyroid (Thrsp) and F-actin binding proteins (Nexilin).