Changes in intraocular pressure and ocular pulse amplitude with accommodation

Aims: To investigate the change that occurs in intraocular pressure (IOP) and ocular pulse amplitude (OPA) with accommodation in young adult myopes and emmetropes. Methods: Fifteen progressing myopic and 17 emmetropic young adult subjects had their IOP and OPA measured using the Pascal dynamic contour tonometer. Measurements were taken initially with accommodation relaxed, and then following 2 min of near fixation (accommodative demand 3 D). Baseline measurements of axial length and corneal thickness were also collected prior to the IOP measures. Results: IOP significantly decreased with accommodation in both the myopic and emmetropic subjects (mean change 1.861.1 mm Hg, p<0.0001). There was no significant difference (p>0.05) between myopes and emmetropes in terms of baseline IOP or the magnitude of change in IOP with accommodation. OPA also decreased significantly with accommodation (mean change for all subjects 0.560.5, p<0.0001). The myopic subjects (baseline OPA 2.060.7 mm Hg) exhibited a significantly lower baseline OPA (p¼0.004) than the emmetropes (baseline OPA 3.261.3 mm Hg),and a significantly lower magnitude of change in OPA with accommodation. Conclusion: IOP decreases significantly with accommodation, and changes similarly in progressing myopic and emmetropic subjects. However, differences found between progressing myopes and emmetropes in the mean OPA levels and the decrease in OPA associated with accommodation suggested some changes in IOP dynamics associated with myopia.

Teaching cause-of-death certification : lessons from international experience

The accuracy of cause-of-death statistics substantially depends on the quality of cause-of-death information in death certificates, primarily completed by medical doctors. Deficiencies in cause-of-death certification have been observed across the world, and over time. Despite educational interventions targeting to improve the quality of death certification, their intended impacts are rarely evaluated. This review aims to provide empirical evidence that could guide the modification of existing educational programs, or the development of new interventions, which are necessary to improve the capacity of certifiers as well as the quality of cause-of-death certification, and thereby, the quality of mortality statistics.

Factors influencing paediatric nurses' responses to medication administration

Objective: To evaluate the importance of contextual and policy factors on nurses’ judgment about medication administration practice.---------- Design: A questionnaire survey of responses to a number of factorial vignettes in June 2004. These vignettes considered a combination of seven contextual and policy factors that were thought to influence nurses’ judgments relating to medication administration.---------- Participants: 185 (67% of eligible) clinical paediatric nursing staff returned completed questionnaires.--------- Setting: A tertiary paediatric hospital in Brisbane, Australia.---------- Results: Double checking the patient, double checking the drug and checking the legality of the prescription were the three strongest predictors of nurses’ actions regarding medication administration.--------- Conclusions: Policy factors and not contextual factors drive nurses’ judgment in response to hypothetical scenarios.

Eccentric calf muscle exercise produces a greater acute reduction in Achilles tendon thickness than concentric exercise

Objective: To investigate the acute effects of isolated eccentric and concentric calf muscle exercise on Achilles tendon sagittal thickness. ---------- Design: Within-subject, counterbalanced, mixed design. ---------- Setting: Institutional. ---------- Participants: 11 healthy, recreationally active male adults. ---------- Interventions: Participants performed an exercise protocol, which involved isolated eccentric loading of the Achilles tendon of a single limb and isolated concentric loading of the contralateral, both with the addition of 20% bodyweight. ---------- Main outcome measurements: Sagittal sonograms were acquired prior to, immediately following and 3, 6, 12 and 24 h after exercise. Tendon thickness was measured 2 cm proximal to the superior aspect of the calcaneus. ---------- Results: Both loading conditions resulted in an immediate decrease in normalised Achilles tendon thickness. Eccentric loading induced a significantly greater decrease than concentric loading despite a similar impulse (−0.21 vs −0.05, p<0.05). Post-exercise, eccentrically loaded tendons recovered exponentially, with a recovery time constant of 2.5 h. The same exponential function did not adequately model changes in tendon thickness resulting from concentric loading. Even so, recovery pathways subsequent to the 3 h time point were comparable. Regardless of the exercise protocol, full tendon thickness recovery was not observed until 24 h. ---------- Conclusions: Eccentric loading invokes a greater reduction in Achilles tendon thickness immediately after exercise but appears to recover fully in a similar time frame to concentric loading.

Dengue fever and el nino-southern oscillation in Queensland, Australia : a time series predictive model

Background It remains unclear over whether it is possible to develop an epidemic forecasting model for transmission of dengue fever in Queensland, Australia. Objectives To examine the potential impact of El Niño/Southern Oscillation on the transmission of dengue fever in Queensland, Australia and explore the possibility of developing a forecast model of dengue fever. Methods Data on the Southern Oscillation Index (SOI), an indicator of El Niño/Southern Oscillation activity, were obtained from the Australian Bureau of Meteorology. Numbers of dengue fever cases notified and the numbers of postcode areas with dengue fever cases between January 1993 and December 2005 were obtained from the Queensland Health and relevant population data were obtained from the Australia Bureau of Statistics. A multivariate Seasonal Auto-regressive Integrated Moving Average model was developed and validated by dividing the data file into two datasets: the data from January 1993 to December 2003 were used to construct a model and those from January 2004 to December 2005 were used to validate it. Results A decrease in the average SOI (ie, warmer conditions) during the preceding 3–12 months was significantly associated with an increase in the monthly numbers of postcode areas with dengue fever cases (β=−0.038; p = 0.019). Predicted values from the Seasonal Auto-regressive Integrated Moving Average model were consistent with the observed values in the validation dataset (root-mean-square percentage error: 1.93%). Conclusions Climate variability is directly and/or indirectly associated with dengue transmission and the development of an SOI-based epidemic forecasting system is possible for dengue fever in Queensland, Australia.

The properties of the international classification of the external cause of injury when used as an instrument for injury prevention research

Objective: To demonstrate properties of the International Classification of the External Cause of Injury (ICECI) as a tool for use in injury prevention research. Methods: The Childhood Injury Prevention Study (CHIPS) is a prospective longitudinal follow up study of a cohort of 871 children 5–12 years of age, with a nested case crossover component. The ICECI is the latest tool in the International Classification of Diseases (ICD) family and has been designed to improve the precision of coding injury events. The details of all injury events recorded in the study, as well as all measured injury related exposures, were coded using the ICECI. This paper reports a substudy on the utility and practicability of using the ICECI in the CHIPS to record exposures. Interrater reliability was quantified for a sample of injured participants using the Kappa statistic to measure concordance between codes independently coded by two research staff. Results: There were 767 diaries collected at baseline and event details from 563 injuries and exposure details from injury crossover periods. There were no event, location, or activity details which could not be coded using the ICECI. Kappa statistics for concordance between raters within each of the dimensions ranged from 0.31 to 0.93 for the injury events and 0.94 and 0.97 for activity and location in the control periods. Discussion: This study represents the first detailed account of the properties of the ICECI revealed by its use in a primary analytic epidemiological study of injury prevention. The results of this study provide considerable support for the ICECI and its further use.

Concurrent and prospective associations between physical activity, walking and mental health in older women

Background Leisure-time physical activity (LTPA) shows promise for reducing the risk of poor mental health in later life, although gender- and age-specific research is required to clarify this association. This study examined the concurrent and prospective relationships between both LTPA and walking with mental health in older women. Methods Community-dwelling women aged 73–78 years completed mailed surveys in 1999, 2002 and 2005 for the Australian Longitudinal Study on Women's Health. Respondents reported their weekly minutes of walking, moderate LTPA and vigorous LTPA. Mental health was defined as the number of depression and anxiety symptoms, as assessed with the Goldberg Anxiety and Depression Scale (GADS). Multivariable linear mixed models, adjusted for socio-demographic and health-related variables, were used to examine associations between five levels of LTPA (none, very low, low, intermediate and high) and GADS scores. For women who reported walking as their only LTPA, associations between walking and GADS scores were also examined. Women who reported depression or anxiety in 1999 were excluded, resulting in data from 6653 women being included in these analyses. Results Inverse dose–response associations were observed between both LTPA and walking with GADS scores in concurrent and prospective models (p<0.001). Even low levels of LTPA and walking were associated with lowered scores. The lowest scores were observed in women reporting high levels of LTPA or walking. Conclusion The results support an inverse dose–response association between both LTPA and walking with mental health, over 3 years in older women without depression or anxiety.

Axial elongation following prolonged near work in myopes and emmetropes

Background/aims: To investigate the influence of a period of sustained near work upon axial length in groups of emmetropes and myopes. Methods: Forty young adult subjects (20 myopes and 20 emmetropes) were recruited for the study. Myopes were further classified as either early onset (EOM), late onset (LOM), stable (SM) or progressing (PM) subgroups. Axial length was measured with the IOLMaster instrument before, immediately after and then again 10 minutes after a continuous 30 minute near task of 5 D accommodation demand. Measures of distance objective refraction were also collected. Results: Significant changes in axial length were observed immediately following the near task. EOM axial length elongated on average by 0.027 ± 0.021 mm, LOM by 0.014 ± 0.020 mm, EMM by 0.010 ± 0.015 mm, PM by 0.031 ± 0.022 mm, and SM by 0.014 ± 0.018 mm. At the conclusion of the 10 minute regression period, axial length measures were not significantly different from baseline values. Conclusion: Axial elongation was observed following a prolonged near task. Both EOM and PM groups showed increases in axial length that were significantly greater than emmetropes

Do walking and leisure-time physical activity protect against arthritis in older women?

Objective: To examine the prospective dose–response relationships between both leisure-time physical activity (LTPA) and walking with self-reported arthritis in older women. Design, setting and participants: Data came from women aged 73–78 years who completed mailed surveys in 1999, 2002 and 2005 for the Australian Longitudinal Study on Women’s Health. Women reported their weekly minutes of walking and moderate to vigorous physical activities. They also reported on whether they had been diagnosed with, or treated for, arthritis since the previous survey. General estimating equation analyses were performed to examine the longitudinal relationship between LTPA and arthritis and, for women who reported walking as their only physical activity, the longitudinal relationship between walking and arthritis. Women who reported arthritis or a limited ability to walk in 1999 were excluded, resulting in data from 3613 women eligible for inclusion in these analyses. Main results: ORs for self-reported arthritis were lowest for women who reported “moderate” levels of LTPA (OR 0.78; 95% CI 0.67 to 0.92), equivalent to 75 to <150 minutes of moderate-intensity LTPA per week. Slightly higher odds ratios were found for women who reported “high” (OR 0.81; 95% CI 0.69 to 0.95) or “very high” (OR 0.84; 95% CI 0.72 to 0.98) LTPA levels, indicating no further benefit from increased activity. For women whose only activity was walking, an inverse dose–response relationship between walking and arthritis was seen. Conclusions: The results support an inverse association between both LTPA and walking with self-reported arthritis over 6 years in older women who are able to walk.

Socioeconomic inequality profiles in physical and developmental health from 0-7 years : Australian National Study

Background: Early and persistent exposure to socioeconomic disadvantage impairs children’s health and wellbeing. However, it is unclear at what age health inequalities emerge or whether these relationships vary across ages and outcomes. We address these issues using cross-sectional Australian population data on the physical and developmental health of children at ages 0-1, 2-3, 4-5 and 6-7 years. Methods: 10 physical and developmental health outcomes were assessed in 2004 and 2006 for two cohorts each comprising around 5000 children. Socioeconomic position was measured as a composite of parental education, occupation and household income. Results: Lower socioeconomic position was associated with increased odds for poor outcomes. For physical health outcomes and socio-emotional competence, associations were similar across age groups and were consistent with either threshold effects (for poor general health, special healthcare needs and socio-emotional competence) or gradient effects (for illness with wheeze, sleep problems and injury). For socio-emotional difficulties, communication, vocabulary and emergent literacy, stronger socioeconomic associations were observed. The patterns were linear or accelerated and varied across ages. Conclusions: From very early childhood, social disadvantage was associated with poorer outcomes across most measures of physical and developmental health and showed no evidence of either strengthening or attenuating at older compared to younger ages. Findings confirm the importance of early childhood as a key focus for health promotion and prevention efforts.

A ∑GIi/D/1/∞ queue with heterogeneous input/output slot times

In this paper, we present a ∑GIi/D/1/∞ queue with heterogeneous input/output slot times. This queueing model can be regarded as an extension of the ordinary GI/D/1/∞ model. For this ∑GIi/D/1/∞ queue, we assume that several input streams arrive at the system according to different slot times. In other words, there are different slot times for different input/output processes in the queueing model. The queueing model can therefore be used for an ATM multiplexer with heterogeneous input/output link capacities. Several cases of the queueing model are discussed to reflect different relationships among the input/output link capacities of an ATM multiplexer. In the queueing analysis, two approaches: the Markov model and the probability generating function technique, are adopted to develop the queue length distributions observed at different epochs. This model is particularly useful in the performance analysis of ATM multiplexers with heterogeneous input/output link capacities.

Marital loss, mental health and the role of perceived social support : findings from six waves of an Australian population based panel study

Objectives: To investigate the impact of transitions out of marriage (separation, widowhood) on the self reported mental health of men and women, and examine whether perceptions of social support play an intervening role. ---------- Methods: The analysis used six waves (2001–06) of an Australian population based panel study, with an analytical sample of 3017 men and 3225 women. Mental health was measured using the MHI-5 scale scored 0–100 (α=0.97), with a higher score indicating better mental health. Perceptions of social support were measured using a 10-item scale ranging from 10 to 70 (α=0.79), with a higher score indicating higher perceived social support. A linear mixed model for longitudinal data was used, with lags for marital status, mental health and social support. ---------- Results: After adjustment for social characteristics there was a decline in mental health for men who separated (−5.79 points) or widowed (−7.63 points), compared to men who remained married. Similar declines in mental health were found for women who separated (−6.65 points) or became widowed (−9.28 points). The inclusion of perceived social support in the models suggested a small mediation effect of social support for mental health with marital loss. Interactions between perceived social support and marital transitions showed a strong moderating effect for men who became widowed. No significant interactions were found for women. ---------- Conclusion: Marital loss significantly decreased mental health. Increasing, or maintaining, high levels of social support has the potential to improve widowed men's mental health immediately after the death of their spouse.

Pedunculopontine nucleus deep brain stimulation produces sustained improvement in primary progressive freezing of gait

Objective: To assess the efficacy of bilateral pedunculopontine nucleus (PPN) deep brain stimulation (DBS) as a treatment for primary progressive freezing of gait (PPFG). ------ ----- Methods: A patient with PPFG underwent bilateral PPN-DBS and was followed clinically for over 14 months. ------ ----- Results: The PPFG patient exhibited a robust improvement in gait and posture following PPN-DBS. When PPN stimulation was deactivated, postural stability and gait skills declined to pre-DBS levels, and fluoro-2-deoxy-d-glucose positron emission tomography revealed hypoactive cerebellar and brainstem regions, which significantly normalised when PPN stimulation was reactivated. ------ ----- Conclusions: This case demonstrates that the advantages of PPN-DBS may not be limited to addressing freezing of gait (FOG) in idiopathic Parkinson's disease. The PPN may also be an effective DBS target to address other forms of central gait failure.

The psychological distress of the young driver : a brief report

Objective: To explore the role of psychological distress in the self-reported risky driving of young novice drivers. Design: Cross-sectional online survey of 761 tertiary students aged 17-25 years with an intermediate (Provisional) driving licence who completed Kessler’s Psychological Distress Scale and the Behaviour of Young Novice Drivers Scale. Setting: Queensland, Australia, August-October 2009. Main outcome measures: Psychological distress, risky driving. Results: Regression analyses revealed that psychological distress uniquely explained 8.5% of the variance in young novice’s risky driving, with adolescents experiencing psychological distress also reporting higher levels of risky driving. Psychological distress uniquely explained a significant 6.7% and 9.5% of variance in risky driving for males and females respectively. Conclusions: Medical practitioners treating adolescents who have been injured through risky behaviour need to aware of the potential contribution of psychological distress, whilst mental health professionals working with adolescents experiencing psychological distress need to be aware of this additional source of potential harm. The nature of the causal relationships linking psychological distress and risky driving behaviour are not yet fully understood, indicating a need for further research so that strategies such as screening can be investigated.

Time course of temperature effects on cardiovascular mortality in Brisbane, Australia

Objective To quantify the lagged effects of mean temperature on deaths from cardiovascular diseases in Brisbane, Australia. Design Polynomial distributed lag models were used to assess the percentage increase in mortality up to 30 days associated with an increase (or decrease) of 1°C above (or below) the threshold temperature. Setting Brisbane, Australia. Patients 22 805 cardiovascular deaths registered between 1996 and 2004. Main outcome measures Deaths from cardiovascular diseases. Results The results show a longer lagged effect in cold days and a shorter lagged effect in hot days. For the hot effect, a statistically significant association was observed only for lag 0–1 days. The percentage increase in mortality was found to be 3.7% (95% CI 0.4% to 7.1%) for people aged ≥65 years and 3.5% (95% CI 0.4% to 6.7%) for all ages associated with an increase of 1°C above the threshold temperature of 24°C. For the cold effect, a significant effect of temperature was found for 10–15 lag days. The percentage estimates for older people and all ages were 3.1% (95% CI 0.7% to 5.7%) and 2.8% (95% CI 0.5% to 5.1%), respectively, with a decrease of 1°C below the threshold temperature of 24°C. Conclusions The lagged effects lasted longer for cold temperatures but were apparently shorter for hot temperatures. There was no substantial difference in the lag effect of temperature on mortality between all ages and those aged ≥65 years in Brisbane, Australia.