Benthic metabolism as an indicator of stream ecosystem health

We tested direct and indirect measures of benthic metabolism as indicators of stream ecosystem health across a known agricultural land-use disturbance gradient in southeast Queensland, Australia. Gross primary production (GPP) and respiration (R24) in benthic chambers in cobble and sediment habitats, algal biomass (as chlorophyll a) from cobbles and sediment cores, algal biomass accrual on artificial substrates and stable carbon isotope ratios of aquatic plants and benthic sediments were measured at 53 stream sites, ranging from undisturbed subtropical rainforest to catchments where improved pasture and intensive cropping are major land-uses. Rates of benthic GPP and R24 varied by more than two orders of magnitude across the study gradient. Generalised linear regression modelling explained 80% or more of the variation in these two indicators when sediment and cobble substrate dominated sites were considered separately, and both catchment and reach scale descriptors of the disturbance gradient were important in explaining this variation. Model fits were poor for net daily benthic metabolism (NDM) and production to respiration ratio (P/R). Algal biomass accrual on artificial substrate and stable carbon isotope ratios of aquatic plants and benthic sediment were the best of the indirect indicators, with regression model R2 values of 50% or greater. Model fits were poor for algal biomass on natural substrates for cobble sites and all sites. None of these indirect measures of benthic metabolism was a good surrogate for measured GPP. Direct measures of benthic metabolism, GPP and R24, and several indirect measures were good indicators of stream ecosystem health and are recommended in assessing process-related responses to riparian and catchment land use change and the success of ecosystem rehabilitation actions.

A comparison of spatially explicit landscape representation methods and their relationship to stream condition

1. Biodiversity, water quality and ecosystem processes in streams are known to be influenced by the terrestrial landscape over a range of spatial and temporal scales. Lumped attributes (i.e. per cent land use) are often used to characterise the condition of the catchment; however, they are not spatially explicit and do not account for the disproportionate influence of land located near the stream or connected by overland flow. 2. We compared seven landscape representation metrics to determine whether accounting for the spatial proximity and hydrological effects of land use can be used to account for additional variability in indicators of stream ecosystem health. The landscape metrics included the following: a lumped metric, four inverse-distance-weighted (IDW) metrics based on distance to the stream or survey site and two modified IDW metrics that also accounted for the level of hydrologic activity (HA-IDW). Ecosystem health data were obtained from the Ecological Health Monitoring Programme in Southeast Queensland, Australia and included measures of fish, invertebrates, physicochemistry and nutrients collected during two seasons over 4 years. Linear models were fitted to the stream indicators and landscape metrics, by season, and compared using an information-theoretic approach. 3. Although no single metric was most suitable for modelling all stream indicators, lumped metrics rarely performed as well as other metric types. Metrics based on proximity to the stream (IDW and HA-IDW) were more suitable for modelling fish indicators, while the HA-IDW metric based on proximity to the survey site generally outperformed others for invertebrates, irrespective of season. There was consistent support for metrics based on proximity to the survey site (IDW or HA-IDW) for all physicochemical indicators during the dry season, while a HA-IDW metric based on proximity to the stream was suitable for five of the six physicochemical indicators in the post-wet season. Only one nutrient indicator was tested and results showed that catchment area had a significant effect on the relationship between land use metrics and algal stable isotope ratios in both seasons. 4. Spatially explicit methods of landscape representation can clearly improve the predictive ability of many empirical models currently used to study the relationship between landscape, habitat and stream condition. A comparison of different metrics may provide clues about causal pathways and mechanistic processes behind correlative relationships and could be used to target restoration efforts strategically.

Dynamic modelling of long-term care decisions

This paper describes and analyzes research on the dynamics of long-term care and the policy relevance of identifying the sources of persistence in caregiving arrangements (including the effect of dynamics on parameter estimates, implications for family welfare, parent welfare, child welfare, and cost of government programs). We discuss sources and causes of observed persistence in caregiving arrangements including inertia/state dependence (confounded by unobserved heterogeneity) and costs of changing caregivers. We comment on causes of dynamics including learning/human capital accumulation; burnout; and game-playing. We suggest how to deal with endogenous geography; dynamics in discrete and continuous choices; and equilibrium issues (multiple equilibria, dynamic equilibria). We also present an overview of commonly used longitudinal data sets and evaluate their relative advantages/disadvantages. We also discuss other data issues related to noisy measures of wealth and family structure. Finally, we suggest some methods to handle econometric problems such as endogeneous geography. © 2014 Springer Science+Business Media New York.

Field validation of controlled Monte Carlo data generation for statistical damage identification employing Mahalanobis squared distance

This article presents the field applications and validations for the controlled Monte Carlo data generation scheme. This scheme was previously derived to assist the Mahalanobis squared distance–based damage identification method to cope with data-shortage problems which often cause inadequate data multinormality and unreliable identification outcome. To do so, real-vibration datasets from two actual civil engineering structures with such data (and identification) problems are selected as the test objects which are then shown to be in need of enhancement to consolidate their conditions. By utilizing the robust probability measures of the data condition indices in controlled Monte Carlo data generation and statistical sensitivity analysis of the Mahalanobis squared distance computational system, well-conditioned synthetic data generated by an optimal controlled Monte Carlo data generation configurations can be unbiasedly evaluated against those generated by other set-ups and against the original data. The analysis results reconfirm that controlled Monte Carlo data generation is able to overcome the shortage of observations, improve the data multinormality and enhance the reliability of the Mahalanobis squared distance–based damage identification method particularly with respect to false-positive errors. The results also highlight the dynamic structure of controlled Monte Carlo data generation that makes this scheme well adaptive to any type of input data with any (original) distributional condition.

The impact of nurse practitioner services on cost, quality of care, satisfaction and wait times in the emergency department: A systematic review

Aims To provide the best available evidence to determine the impact of nurse practitioner services on cost, quality of care, satisfaction and waiting times in the emergency department for adult patients. Background The delivery of quality care in the emergency department is one of the most important service indicators in health delivery. Increasing service pressures in the emergency department have resulted in the adoption of service innovation models: the most common and rapidly expanding of these is emergency nurse practitioner services. The rapid uptake of emergency nurse practitioner service in Australia has outpaced the capacity to evaluate this service model in terms of outcomes related to safety and quality of patient care. Previous research is now outdated and not commensurate with the changing domain of delivering emergency care with nurse practitioner services. Data A comprehensive search of four electronic databases from 2006-­‐2013 was conducted to identify research evaluating nurse practitioner service impact in the emergency department. English language articles were sought using MEDLINE, CINAHL, Embase and Cochrane and included two previous systematic reviews completed five and seven years ago. Methods A three step approach was used. Following a comprehensive search, two reviewers assessed identified studies against the inclusion criteria. From the original 1013 studies, 14 papers were retained for critical appraisal on methodological quality by two independent reviewers and data extracted using standardised tools. Results Narrative synthesis was conducted to summarise and report the findings as insufficient data was available for meta-­‐analysis of results. This systematic review has shown that emergency nurse practitioner service has a positive impact on quality of care, patient satisfaction and waiting times. There was insufficient evidence to draw conclusions regarding impact on costs. Conclusion Synthesis of the available research attempts to provide an evidence base for emergency nurse practitioner service to guide healthcare leaders, policy makers and clinicians in reforming emergency department service provision. The findings suggest that further quality research is required for comparative measures of clinical and service effectiveness of emergency nurse practitioner service. In the context of increased health service demand and the need to provide timely and effective care to patients, such measures will assist in delivering quality patient care.

The effect of hip muscle strengthening on pain and disability for individuals with non-specific low back pain : a randomized controlled trial

Introduction Clinical guidelines for the treatment of chronic low back pain suggest the use of supervised exercise. Motor control (MC) based exercise is widely used within clinical practice but its efficacy is equivalent to general exercise therapy. MC exercise targets the trunk musculature. Considering the mechanical links between the hip, pelvis, and lumbar spine, surprisingly little focus has been on investigating the contribution of the hip musculature to lumbopelvic support. The purpose of this study is to compare the efficacy of two exercise programs for the treatment of non-specific low back pain (NSLBP). Methods Eighty individuals aged 18-65 years of age were randomized into two groups to participate in this trial. The primary outcome measures included self-reported pain intensity (0-100mm VAS) and percent disability (Oswestry Disability Index V2). Bilateral measures of hip strength (N/kg) and two dimensional frontal plane mechanics (º) were the secondary outcomes. Outcomes were measured at baseline and following a six-week home based exercise program including weekly sessions of real-time ultrasound imaging. Results Within group comparisons revealed clinically meaningful reductions in pain for both groups. The MC exercise only (N= 40, xˉ =-20.9mm, 95%CI -25.7, -16.1) and the combined MC and hip exercise (N= 40, xˉ = -24.9mm, 95%CI -30.8, -19.0). There was no statistical difference in the change of pain (xˉ =-4.0mm, t= -1.07, p=0.29, 95%CI -11.5, 3.5) or disability (xˉ =-0.3%, t=-0.19, p=0.85, 95%CI -11.5, 3.5) between groups. Conclusion Both exercise programs had similar and positive effects on NSLBP which support the use of the home based exercise programs with weekly supervised visits. However, the addition of specific hip strengthening exercises to a MC based exercise program did not result in significantly greater reductions in pain or disability. Trial Registration NCTO1567566 Funding: Worker’s Compensation Board Alberta Research Grant.

Displaced twice? Talking about resilience with a cohort of men from refugee backgrounds who were affected by the 2011 Queensland floods

What can we learn from people from refugee backgrounds who have been affected by an environmental disaster? This paper presents the first year findings of a study that is investigating the impact of the 2011 Queensland floods on a cohort of men from refugee backgrounds living in Brisbane and the Toowoom- ba–Gatton region of Southeast Queensland. Between 2008 and 2010, the SettleMEN study yielded pre-disaster measures of health and settlement among 233 refugee men. The current 2012−2013 follow-up study offers a rare opportunity to investigate and describe the impact of an environmental disaster on the health and wellbeing of a group of resettled refugee men who were affected by the 2011 Queensland floods. Using a mixed-method approach and a peer interviewer model, this paper reports on the exposure to and impact of the floods on the first 100 respondents who were interviewed between September 2012 and March 2013. Overall, we have found that the floods had a considerable economic and psychosocial impact on this group of men, their families and communities in terms of being forced to evacuate their homes, work disrup- tion, loss of income and personal belongings, and emotional distress. Many of these men reported that their previous refugee experience helped them to cope better during and after the floods, and for some, providing assistance to others during the floods impacted positively on their relationship with their neighbours. These findings challenge the Western deficits model that defines former refugees as traumatised victims. Refugee people’s strengths and capabilities should be taken into consideration when developing disaster response strategies at the neighbourhood and community levels.

The corporate governance effects of audit committees

Arguments associated with the promotion of audit committees in many countries are premised on their potential for alleviating weaknesses in corporate governance. This paper provides a synthesis and evaluation of empirical research on the governance effects associated with audit committees. Given recent policy recommendations in several countries aimed at strengthening these committees, it is important to establish what research evidence demonstrates about their existing governance contribution. A framework for analyzing the impact of audit committees is described, identifying potential perceived effects which may have led to their adoption and documented effects on aspects of the audit function, on financial reporting quality and on corporate performance. It is argued that there is only limited and mixed evidence of effects to support claims and perceptions about the value of audit committees for these elements of governance. It is also shown that most of the existing research has focused on factors associated with audit committee existence, characteristics and measures of activity and there is very little evidence on the processes associated with the operation of audit committees and the manner in which they influence organizational behaviour. It is clear that there is no automatic relationship between the adoption of audit committee structures or characteristics and the achievement of particular governance effects, and caution may be needed over expectations that greater codification around factors such as audit committee members’ independence and expertise as the means of ‘‘correcting’’ past weaknesses in the arrangements for audit committees. The most fundamental question concerning what difference audit committees make in practice continues to be an important area for research development. For future research we suggest: (i) greater consideration of the organizational and institutional contexts in which audit committees operate; (ii) explicit theorization of the processes associated with audit committee operation; (iii) complementing extant research methods with field studie, and; (iv) investigation of unintended (behavioural) as well as expected consequences of audit committees.

Psycho-educational assessment of specific learning disabilities: Views and practices of Australian psychologists and guidance counsellors

This paper reports an investigation of the views and practices of 203 Australian psychologists and guidance counsellors with respect to psycho-educational assessment of students with Specific Learning Disabilities (SLDs). Results from an online survey indicated that practitioners draw upon a wide-range of theoretical perspectives when conceptualising and identifying SLDs, including both response to intervention and IQ – achievement discrepancy models. Intelligence tests (particularly the Wechsler scales) are commonly employed, with the main stated reasons for their use being ‘traditional’ perspectives (including IQ-achievement discrepancy-based definitions of SLDs), to exclude a diagnosis of intellectual disability, and to guide further assessment and intervention. In contrast participants reported using measures of academic achievement and tests of specific cognitive deficits known to predict SLDs (e.g., phonological awareness) relatively infrequently.

Explicating the role of sexual coercion and vulnerability: Alcohol expectancies in rape attributions

Despite evidence suggesting that alcohol expectancies may influence people’s rape perceptions, no study to date has measured context-specific expectancies comprehensively. This study represents an initial investigation of the role of sexual coercion and vulnerability alcohol expectancies in young Australian adults’ rape blame attributions. Using a vignette method, it was hypothesised that participants’ stronger expectancy endorsement would predict lesser perpetrator blame and greater victim blame. Participants (N = 210; 34.9% males; 18-25 years) read a hypothetical rape scenario and rated dimensions of blameworthiness attributed to the intoxicated sexual perpetrator and victim. Participants completed the Sexual Coercion and Sexual Vulnerability sub-scales of the Drinking Expectancy Sexual Vulnerabilities Questionnaire for the targets self, men, and women in addition to measures of traditional gender role attitudes and rape myth acceptance. Hierarchical multiple regressions revealed that, as expected, stronger sexual coercion expectancy predicted lower perpetrator blame and greater victim blame. Self-oriented expectancy predicted evaluations of the perpetrator whereas other-oriented expectancy predicted victim evaluations. These effects were robust after controlling for gender role attitudes and rape myth acceptance. Alcohol expectancies appear to be part of a network of beliefs and attitudes which perpetuate biased rape attributions and may be useful to challenge in altering rape perceptions.

The effect of previous hamstring strain injuries on the change in eccentric hamstring strength during preseason training in elite Australian footballers

Background Hamstring strain injuries (HSIs) are the most common injury type in Australian football and the rate of recurrence has been consistently high for a number of years. Long lasting neuromuscular inhibition has been noted in previously injured athletes but it is not known if this influences athletes adaptive response to training. Purpose To determine if elite Australian footballers with a prior unilateral HSI (previously injured group) display lesser improvements in eccentric hamstring strength during pre-season training compared to athletes without a history of HSI (control group). Study design Prospective cohort study. Methods Ninety-nine elite Australian footballers participated (17 with a history of unilateral HSI in the previous 12 month period). Eccentric hamstring strength was assessed at the start and end of pre-season training using an instrumented Nordic hamstring device. Change in eccentric strength across preseason was determine in absolute terms and normalised to start of preseason strength. Start of preseason strength was used as a covariate to control for differences in starting strength. Results The left and right limbs in the control group showed no difference in absolute or relative change (left limb absolute change, 60.7±72.9N; relative change, 1.28±0.34; right limb absolute change, 48.6±83.8N; relative change, 1.24±0.43) . Similarly, the injured and uninjured limbs from the previously injured group showed no difference for either absolute or relative measures of change (injured limb absolute change, 13.1±57.7N; relative change, 1.07±0.18; uninjured limb absolute change, 14.7±54.0N; relative change, 1.07±0.22N). The previously injured group displayed a significantly lesser increase in eccentric hamstring strength across the preseason (absolute change, 13.9±55.0; relative change, 1.07±0.20) compared to the control group (absolute change, 54.6±78.5; relative change, 1.26±0.39) for both absolute and relative measures (p < 0.001), even after controlling for differences in start of pre-season eccentric hamstring strength, which had a significant effect on strength improvement. Conclusion Elite Australian footballers with a unilateral HSI history displayed lesser improvements in eccentric hamstring strength across preseason training. The smaller improvements were not restricted to the previously injured limb as the contralateral limb also displayed similarly small improvements in eccentric strength. Whether this is the cause of or the result of injury remains to be seen, but it has the potential to contribute to the risk of hamstring strain re-injury.

Wood density : a tool to find complementary species for the design of mixed species plantations

The successful establishment and growth of mixed-species forest plantations requires that complementary or facilitatory species be identified. This can be difficult in many tropical areas because the growth characteristics of endemic species are often unknown, particularly when grown at potentially higher densities in plantations than in natural forests. Here, we investigate whether wood density is a useful and readily accessible trait for choosing complementary species for mixed species plantations. Wood density represents the carbon investment per unit volume of stem with a trade-off generally found between fast (low wood density) and slow (high wood density) growing species. To do this, we use data collected from 18 highly diverse mixed species plantations (4–23 mostly native species) aged from 6 to 11 years at the time of data collection located on Leyte Island, Philippines. We found significant negative correlations between wood densities and the height of the most abundant species, as well as with measures of overall stand growth and tree diameter size distribution. Not only do species with denser woods have slower growth rates, but also mixed-species plantations with higher average wood density and higher stem density were also less productive, at least in these young plantations. Similarly, stands with a high diversity in wood densities were less productive. There is growing interest in making greater use of native multi-species mixtures in smallholder and community planting programs in the tropics, and our results show databases of wood density values may help improve their design. In the early development stages of plantations, canopy closure and rapid height growth are usually key silvicultural targets, and wood density values can predict the rapid height development of species. If plantations are being grown for the livelihood of small landholders then the best target is to choose some species with different wood densities. This allows an early harvest of low-wood density species for early income, and will also reduce competition for slower growing trees with higher wood densities for later income generation.

Differential effects of refractive blur on day and night-time driving performance

Purpose To investigate the effect of different levels of refractive blur on real-world driving performance measured under day and nighttime conditions. Methods Participants included 12 visually normal, young adults (mean age = 25.8 ± 5.2 years) who drove an instrumented research vehicle around a 4 km closed road circuit with three different levels of binocular spherical refractive blur (+0.50 diopter sphere [DS], +1.00 DS, +2.00 DS) compared with a baseline condition. The subjects wore optimal spherocylinder correction and the additional blur lenses were mounted in modified full-field goggles; the order of testing of the blur conditions was randomized. Driving performance was assessed in two different sessions under day and nighttime conditions and included measures of road signs recognized, hazard detection and avoidance, gap detection, lane-keeping, sign recognition distance, speed, and time to complete the course. Results Refractive blur and time of day had significant effects on driving performance (P < 0.05), where increasing blur and nighttime driving reduced performance on all driving tasks except gap judgment and lane keeping. There was also a significant interaction between blur and time of day (P < 0.05), such that the effects of blur were exacerbated under nighttime driving conditions; performance differences were evident even for +0.50 DS blur relative to baseline for some measures. Conclusions The effects of blur were greatest under nighttime conditions, even for levels of binocular refractive blur as low as +0.50 DS. These results emphasize the importance of accurate and up-to-date refractive correction of even low levels of refractive error when driving at night.

The visual and functional impacts of astigmatism and its clinical management

Purpose: To provide a comprehensive overview of research examining the impact of astigmatism on clinical and functional measures of vision, the short and longer term adaptations to astigmatism that occur in the visual system, and the currently available clinical options for the management of patients with astigmatism. Recent findings: The presence of astigmatism can lead to substantial reductions in visual performance in a variety of clinical vision measures and functional visual tasks. Recent evidence demonstrates that astigmatic blur results in short-term adaptations in the visual system that appear to reduce the perceived impact of astigmatism on vision. In the longer term, uncorrected astigmatism in childhood can also significantly impact on visual development, resulting in amblyopia. Astigmatism is also associated with the development of spherical refractive errors. Although the clinical correction of small magnitudes of astigmatism is relatively straightforward, the precise, reliable correction of astigmatism (particularly high astigmatism) can be challenging. A wide variety of refractive corrections are now available for the patient with astigmatism, including spectacle, contact lens and surgical options. Conclusion: Astigmatism is one of the most common refractive errors managed in clinical ophthalmic practice. The significant visual and functional impacts of astigmatism emphasise the importance of its reliable clinical management. With continued improvements in ocular measurement techniques and developments in a range of different refractive correction technologies, the future promises the potential for more precise and comprehensive correction options for astigmatic patients.

Natural history of corneal nerve morphology in mild neuropathy associated with type 1 diabetes : Development of a potential measure of diabetic peripheral neuropathy

Purpose To investigate longitudinal changes of subbasal nerve plexus (SNP) morphology and its relationship with conventional measures of neuropathy in individuals with diabetes. Methods A cohort of 147 individuals with type 1 diabetes and 60 age-balanced controls underwent detailed assessment of clinical and metabolic factors, neurologic deficits, quantitative sensory testing, nerve conduction studies and corneal confocal microscopy at baseline and four subsequent annual visits. The SNP parameters included corneal nerve fiber density (CNFD), branch density (CNBD) and fiber length (CNFL) and were quantified using a fully-automated algorithm. Linear mixed models were fitted to examine the changes in corneal nerve parameters over time. Results At baseline, 27% of the participants had mild diabetic neuropathy. All SNP parameters were significantly lower in the neuropathy group compared to controls (P<0.05). Overall, 89% of participants examined at baseline also completed the final visit. There was no clinically significant change to health and metabolic parameters and neuropathy measures from baseline to the final visit. Linear mixed model revealed a significant linear decline of CNFD (annual change rate, -0.9 nerve/mm2, P=0.01) in the neuropathy group compared to controls, which was associated with age (β=-0.06, P=0.04) and duration of diabetes (β=-0.08, P=0.03). In the neuropathy group, absolute changes of CNBD and CNFL showed moderate correlations with peroneal conduction velocity and cold sensation threshold, respectively (rs, 0.38 and 0.40, P<0.05). Conclusion This study demonstrates dynamic small fiber damage at the SNP, thus providing justification for our ongoing efforts to establish corneal nerve morphology as an appropriate adjunct to conventional measures of DPN.