Teaching and Learning Science through Multiple Representations: Intuitions and Executive Functions.

Reasoning about visual representations in science requires the ability to control one's attention, inhibit attention to irrelevant or incorrect information, and hold information in mind while manipulating it actively-all aspects of the limited-capacity cognitive system described as humans' executive functions. This article describes pedagogical intuitions on best practices for how to sequence visual representations among pre-service teachers, adult undergraduates, and middle school children, with learning also tested in the middle school sample. Interestingly, at all ages, most people reported beliefs about teaching others that were different from beliefs about how they would learn. Teaching beliefs were most often that others would learn better from presenting representations one at a time, serially; while learning beliefs were that they themselves would learn best from simultaneous presentations. Students did learn best from simultaneously presented representations of mitosis and meiosis, but only when paired with self-explanation prompts to discuss the relationships between the graphics. These results provide new recommendations for helping students draw connections across visual representations, particularly mitosis and meiosis, and suggest that science educators would benefit from shifting their teaching beliefs to align with beliefs about their own learning from multiple visual representations.

Functional haplotypes in the PTGDR gene fail to associate with asthma in two Australian populations.

BACKGROUND AND OBJECTIVE: Haplotypes in the promoter region of the prostanoid DP receptor (PTGDR) gene have been shown to functionally influence gene transcription and to be associated with asthma in two previous case-control studies in Caucasians. This study tested the association of PTGDR haplotypes with asthma phenotypes in two large Caucasian-Australian populations. These results were incorporated in a meta-analysis with previously published data to determine the overall role for these haplotypes in the risk of asthma. METHODS: Three PTGDR promoter-region single nucleotide polymorphisms (SNP) were genotyped in 368 individuals from the Western Australian Twin Child Health study and 2988 individuals from the Busselton Health Study. Logistic regression and transition disequilibrium tests were used to assess whether SNP genotypes and three SNP haplotypes were associated with doctor-diagnosed asthma or intermediate quantitative traits. Longitudinal data from the Busselton Health Study were used to examine whether PTGDR influences changes in lung function over time. Meta-analysis incorporated the findings of this study with those of two previous studies in Caucasian populations. RESULTS: Cross-sectional associations between PTGDR haplotypes and asthma phenotypes were non-significant (P > 0.05) in both populations. Longitudinal analyses of PTGDR and lung function were also non-significant. Meta-analysis, however, suggested that haplotype TCT was significantly associated with decreased risk of asthma (OR = 0.76; P = 0.02) while haplotype CCC was not significantly associated with asthma (OR = 1.30; P = 0.07). CONCLUSIONS: These results suggest that despite the non-significant findings in the present study populations, PTGDR promoter haplotypes may account for a small but significant proportion of the risk of asthma in Caucasian populations.

Readiness to shop for low-fat foods: a population study.

BACKGROUND: Stages of change are related to dietary fat consumption. Few studies have examined stage occupation within the context of purchasing low-fat foods. OBJECTIVE: To determine the stage-prevalence of individuals for purchasing low-fat foods; identify the frequency of misclassification into action and maintenance (A/M) stages for purchasing for low-fat foods; and explain the demographic and cognitive-variable differences between pseudo (or false positive) A/M and true A/M individuals. DESIGN: Data were collected using a self-administered questionnaire among English-speaking adults (n=1,001) who were randomly sampled by mail. STATISTICAL ANALYSES PERFORMED: Descriptive statistics were used to compare the characteristics of the stage groups. Groups were compared using chi(2) tests and Student t test. RESULTS: Of those who reported being in A/M stages, 32% were misclassified by the staging algorithm and were not true A/M low-fat food purchasers. CONCLUSIONS: Individuals who are in A/M stages for buying low-fat foods still purchase high-fat foods. Stage misclassification may be a persistent problem in studies of dietary change using the Transtheoretical Model.

Impact of an anemia clinic on emergency room visits and hospitalizations in patients with anemia of CKD pre-dialysis.

AIM: There is limited data regarding the impact on hospital resource use of a dedicated, nurse-managed anemia clinic in patients with pre-end stage chronic kidney disease. METHODS: A retrospective cohort study was conducted comparing patients with pre-end stage anemia of chronic kidney disease enrolled in an algorithmic anemia clinic (N = 27, treatment group) with un-enrolled patients with chronic kidney disease (N = 22, control group). The treatment group received algorithmic treatment with recombinant human erythropoietin and intravenous iron sucrose, while controls received usual care. The primary outcomes investigated were emergency room visits and hospitalizations during a 1-year period. RESULTS: The two groups were similar at baseline. During the first year of clinic enrollment, the mean hemoglobin values improved in the treatment group from baseline and compared with controls (11.6 +/- 1.2 g/dl vs. 10.3 +/- 1.0 g/dl, p < 0.05). The relative risk of an emergency room visit (RR 0.18, 95% CI 0.05-0.67, p < 0.05) and hospitalization (RR 0.20, 95% CI 0.06-0.67, p < 0.05) were reduced in the treatment group versus the control group. The average length of hospital stay was also reduced (6.8 days vs. 9.5 days, p = 0.05). CONCLUSION: Enrollment in a dedicated nurse-managed anemia clinic is significantly associated with reduced emergency room visits and hospitalizations in patients with pre-end stage CKD. These associative findings justify future prospective analyses to establish causality.

Age and sex differences in malignant mesothelioma after residential exposure to blue asbestos (crocidolite).

BACKGROUND: Blue asbestos was mined and milled at Wittenoom, Western Australia, from 1943 until 1966. Various public records were used to establish a cohort of residents of the nearby township. Mine tailings were distributed throughout the town. AIMS: To report the incident number of malignant mesotheliomas that have occurred in residents of the town who did not work at the mine or mill; and to determine if female subjects are more susceptible to asbestos exposure than male subjects, and if children are more susceptible than adults. SUBJECTS AND METHODS: A total of 4,768 residents of the town of Wittenoom have been followed up in cancer and death registries. RESULTS: There were 67 cases of mesothelioma, and 64 deaths with mesothelioma to the end of 2002. The mortality rate with mesothelioma increased with increasing residence duration, time since first exposure, and estimated cumulative exposure. The mesothelioma mortality rate was consistently lower for female subjects when compared with male subjects, but the dose-response curve was steeper for female subjects. The rate was lower in those first exposed as children compared with those first exposed at > or = 15 years of age. The dose-response slope for asbestos exposure and mortality from mesothelioma was not different between those who were first exposed as children than those who were first exposed at > or = 15 years of age. CONCLUSIONS: Former residents of a crocidolite mining town have a high rate of mesothelioma. The rate is higher in male subjects and those > or = 15 years of age at first exposure, but women have a steeper dose-response curve.

The Western Australian Register of Childhood Multiples: effects of questionnaire design and follow-up protocol on response rates and representativeness.

Twin registers have been established worldwide to study the roles of genes and the environment in health and behaviour. While questionnaire surveys are thought to be the most cost-effective way of collecting large amounts of data, low response rates can result in response bias. Many different strategies have been proposed to maximise response rates. A register of all multiple births occurring in Western Australia (WA) from 1980 onwards has been established using probabilistic record linkage techniques. Families who had not experienced the death of one or more of their multiples were invited to participate in the Western Australian Twin Child Health (WATCH) study, which studied the genetic and environmental determinants of childhood asthma and atopy. Several questionnaire designs and follow-up methods were assessed. We have shown that it was feasible to use a population-based register of multiple births to contact families for a questionnaire study. Questionnaire length, mode of follow-up, the number of responses required and the of participants all seemed to affect response.

Population based ascertainment of twins and their siblings, born in Western Australia 1980 to 1992, through the construction and validation of a maternally linked database of siblings.

This paper describes the creation of a unique maternal identifier for use in the investigation of perinatal, postneonatal and child outcomes in relation to maternal characteristics. All Midwives' records of Western Australian (WA) births were routinely linked to registrations of births and deaths for infants born from 1980 to 1992 inclusive, then linked to WA hospital discharge data and to registries of birth defects and cerebral palsy to create a longitudinal health record for each infant. However, since each birth to a woman was recorded as a separate event, there was no way to identify siblings. Probabilistic record linkage, based on information about the mother, was used for this task. Logical inconsistencies within the data were used to test the validity of the linkages between birth records attributed to each mother. Information about the mother from other epidemiological studies and data abstracted from hospital case notes was also used to validate sibships. Linkage of the records of 310,255 births in WA during that period resulted in the formation of 181,133 sibships of one or more children. Pooling the results of all of the validation methods gave an error of 0.9%. Linkage identified 3678 sibships containing multiple births, and 305 sets of maternal twins. Ascertainment of twins and their siblings for an ongoing twin register, the WA Twin Child Health (WATCH) study, was a natural consequence of this process.