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Critical care echocardiography is developing rapidly with an increasing number of specialists now performing comprehensive studies using Doppler and other advanced techniques. However, this imaging can be challenging, interpretation is far from simple in the complex critically ill patient and mistakes can be easy to make. We aim to address clinically relevant areas where potential errors may occur and suggest methods to hopefully improve accuracy of imaging and interpretation.

This pilot study aimed to characterise the haemodynamic effect of 1L of IV normal saline (NS) administered as a rapid versus slow infusion on cardiac output (CO), heart rate (HR), systemic blood pressures, and carotid blood flow in six healthy volunteers. Six healthy male volunteers aged 18–65years were randomized to receive 1L NS given over 30min or 120min. On a subsequent study session the alternate fluid regimen was administered. Haemodynamic data was gathered using a non-invasive finger arterial pressure monitor (Nexfin®), echocardiography and carotid duplex sonography. Time to micturition and urine volume was also assessed. Compared to baseline, rapid infusion of 1L of saline over 30min produced a fall in Nexfin®-measured CO by 0.62L/min (p<0.001), whereas there was a marginal but significant increase during infusion of 1L NS over 120min of 0.02L/min (p<0.001). This effect was mirrored by changes in HR and blood pressure (BP) (p<0.001). There were no significant changes in carotid blood flow, time to micturition, or urine volume produced. Slower infusion of 1L NS in healthy male volunteers produced a greater increase in CO, HR and BP than rapid infusion. •A randomized crossover controlled interventional volunteer study•Comparison of rapid versus slower infusion of 1L IV crystalloid•Significantly greater non-invasively measured CO, HR, and BP effects demonstrated•Further investigation of these comparative effects in patients is needed

Square dancing is a popular music-related group physical exercise for health benefits in China mainly participated by mid-aged women and elderly people. This paper investigates the soundscape and enjoyment of the square dancing in urban streets through a case study in Lichuan, a county level city in southwest China, in December 2017. It examines the impact of gender, age, participation and places on perceptions of square dancing soundscape. Two sites along two main urban streets in the city were selected to conduct onsite investigations where residents spontaneously perform square dancing on a daily basis. Ethnographical observations were conducted to identify the social-physical features and sounds of both sites during the dance and without dance. Sound pressure measurements (LAeq and LAmax) were also conducted under the two conditions. An off-site survey was distributed through the local social media groups to understand residents’ everyday experiences and perceptions of square dancing in the city; 106 responses were received for the off-site survey. T-tests and Chi-squared tests were used for statistical analysis of the survey data. The results show gender does appear to be a factor influencing the regularity of participation in square dancing, with a bias towards more female participants. Participation frequency of square dance has an impact on the enjoyment of square dancing. There is no correlation between the dislike of watching square dancing, or dislike of the music and a desire to restrict locations for square dancing.

We examine management discretion to decide when and how much to write down an asset, in a unique case where a tracking stock provides an observable market value for the asset. We find that, despite market evidence that Inco Ltd.'s financial statements substantially overvalued the Voisey's Bay nickel mine throughout 1997 to 2000, management chose not to write down the mine until 2002. Inco management used an independent fairness opinion to justify its December 2000 redemption of the tracking stock at 25% of its initial value, indicating almost surely that Inco management was aware of the generally accepted accounting principles (GAAP) impairment. This case illustrates that GAAP's reliance on undiscounted cash flows for impairment decisions allows huge unrecorded disparities between book and market value. The management discretion exercised in this case provides a concrete example of the subjectivity inherent in fair valuation.

Objective National health workforce data are used in workforce projections, policy and planning. If data to measure the current effective clinical medical workforce are not consistent, accurate and reliable, policy options pursued may not be aligned with Australia's actual needs. The aim of the present study was to identify any inconsistencies and contradictions in the numerical count of paediatric specialists in Australia, and discuss issues related to the accuracy of collection and analysis of medical workforce data. Methods This study compared respected national data sources regarding the number of medical practitioners in eight fields of paediatric speciality medical (non-surgical) practice. It also counted the number of doctors listed on the websites of speciality paediatric hospitals and clinics as practicing in these eight fields. Results Counts of medical practitioners varied markedly for all specialties across the data sources examined. In some fields examined, the range of variability across data sources exceeded 450%. Conclusions The national datasets currently available from federal and speciality sources do not provide consistent or reliable counts of the number of medical practitioners. The lack of an adequate baseline for the workforce prevents accurate predictions of future needs to provide the best possible care of children in Australia. What is known about the topic? Various national data sources contain counts of the number of medical practitioners in Australia. These data are used in health workforce projections, policy and planning. What does this paper add? The present study found that the current data sources do not provide consistent or reliable counts of the number of practitioners in eight selected fields of paediatric speciality practice. There are several potential issues in the way workforce data are collected or analysed that cause the variation between sources to occur. What are the implications for practitioners? Without accurate data on which to base decision making, policy options may not be aligned with the actual needs of children with various medical needs, in various geographic areas or the nation as a whole.

The objective of this study was to assess the accuracy of blind placement of caudal epidural needles and the usefulness of the radio-contrast epidurogram. The study involves a prospective case series of 147 consecutive patients with radiological assessment of blind needle placement and epidurogram assessing the accuracy of blind needle placement in caudal epidurals. When the surgical miss rate (26%) and failure of flow of the therapeutic agents (6%) are combined, it can be deduced that up to 32% of non-radiologically guided caudal epidurals may fail to deliver the therapeutic agents to the site of pathology. There was no significant difference in the accuracy of needle placement in adequately trained and experienced middle grade surgeons when compared with consultant surgeons performing these procedures regularly. In conclusion, we recommend radiological guidance and use of epidurogram as the gold standard for the administration of caudal epidurals to increase the likelihood of successful delivery of the therapeutic agents to the site of pathology during the procedure.

Background As greater numbers of us are living longer, it is increasingly important to understand how we can age healthily. Although old age is often stereotyped as a time of declining mental abilities and inflexibility, cognitive neuroscience reveals that older adults use neural and cognitive resources flexibly, recruiting novel neural regions and cognitive processes when necessary. Our aim in this project is to understand how age-related changes to neural structure and function interact to support cognitive abilities across the lifespan. Methods/Design We are recruiting a population-based cohort of 3000 adults aged 18 and over into Stage 1 of the project, where they complete an interview including health and lifestyle questions, a core cognitive assessment, and a self-completed questionnaire of lifetime experiences and physical activity. Of those interviewed, 700 participants aged 18-87 (100 per age decile) continue to Stage 2 where they undergo cognitive testing and provide measures of brain structure and function. Cognition is assessed across multiple domains including attention and executive control, language, memory, emotion, action control and learning. A subset of 280 adults return for in-depth neurocognitive assessment in Stage 3, using functional neuroimaging experiments across our key cognitive domains. Formal statistical models will be used to examine the changes that occur with healthy ageing, and to evaluate age-related reorganisation in terms of cognitive and neural functions invoked to compensate for overall age-related brain structural decline. Taken together the three stages provide deep phenotyping that will allow us to measure neural activity and flexibility during performance across a number of core cognitive functions. This approach offers hypothesis-driven insights into the relationship between brain and behaviour in healthy ageing that are relevant to the general population. Discussion Our study is a unique resource of neuroimaging and cognitive measures relevant to change across the adult lifespan. Because we focus on normal age-related changes, our results may contribute to changing views about the ageing process, lead to targeted interventions, and reveal how normal ageing relates to frail ageing in clinicopathological conditions such as Alzheimer's disease.

The control of voluntary movement changes markedly with age. A critical component of motor control is the integration of sensory information with predictions of the consequences of action, arising from internal models of movement. This leads to sensorimotor attenuation—a reduction in the perceived intensity of sensations from self-generated compared with external actions. Here we show that sensorimotor attenuation occurs in 98% of adults in a population-based cohort ( n =325; 18–88 years; the Cambridge Centre for Ageing and Neuroscience). Importantly, attenuation increases with age, in proportion to reduced sensory sensitivity. This effect is associated with differences in the structure and functional connectivity of the pre-supplementary motor area (pre-SMA), assessed with magnetic resonance imaging. The results suggest that ageing alters the balance between the sensorium and predictive models, mediated by the pre-SMA and its connectivity in frontostriatal circuits. This shift may contribute to the motor and cognitive changes observed with age. Decline in sensorimotor skills with age may be due to an overreliance on the prediction of the sensory consequences of one’s actions. Here the authors show that sensorimotor attenuation increases with age, and that this is associated with structural and functional changes in frontostriatal circuits.

Ageing is characterized by declines on a variety of cognitive measures. These declines are often attributed to a general, unitary underlying cause, such as a reduction in executive function owing to atrophy of the prefrontal cortex. However, age-related changes are likely multifactorial, and the relationship between neural changes and cognitive measures is not well-understood. Here we address this in a large ( N =567), population-based sample drawn from the Cambridge Centre for Ageing and Neuroscience (Cam-CAN) data. We relate fluid intelligence and multitasking to multiple brain measures, including grey matter in various prefrontal regions and white matter integrity connecting those regions. We show that multitasking and fluid intelligence are separable cognitive abilities, with differential sensitivities to age, which are mediated by distinct neural subsystems that show different prediction in older versus younger individuals. These results suggest that prefrontal ageing is a manifold process demanding multifaceted models of neurocognitive ageing. Executive functions are affected by ageing but it is unclear how. Kievit et al. use brain imaging and modelling approaches to show how multifactorial explanations outperform single-factor models when relating age-related differences in grey and white matter to differences in fluid intelligence and multitasking.

Neural activity cannot be directly observed using fMRI; rather it must be inferred from the hemodynamic responses that neural activity causes. Solving this inverse problem is made possible through the use of forward models, which generate predicted hemodynamic responses given hypothesised underlying neural activity. Commonly‐used hemodynamic models were developed to explain data from healthy young participants; however, studies of ageing and dementia are increasingly shifting the focus toward elderly populations. We evaluated the validity of a range of hemodynamic models across the healthy adult lifespan: from basis sets for the linear convolution models commonly used to analyse fMRI studies, to more advanced models including nonlinear fitting of a parameterised hemodynamic response function (HRF) and nonlinear fitting of a biophysical generative model (hemodynamic modelling, HDM). Using an exceptionally large sample of participants, and a sensorimotor task optimized for detecting the shape of the BOLD response to brief stimulation, we first characterised the effects of age on descriptive features of the response (e.g., peak amplitude and latency). We then compared these to features from more complex nonlinear models, fit to four regions of interest engaged by the task, namely left auditory cortex, bilateral visual cortex, left (contralateral) motor cortex and right (ipsilateral) motor cortex. Finally, we validated the extent to which parameter estimates from these models have predictive validity, in terms of how well they predict age in cross‐validated multiple regression. We conclude that age‐related differences in the BOLD response can be captured effectively by models with three free parameters. Furthermore, we show that biophysical models like the HDM have predictive validity comparable to more common models, while additionally providing insights into underlying mechanisms, which go beyond descriptive features like peak amplitude or latency, and include estimation of nonlinear effects. Here, the HDM revealed that most of the effects of age on the BOLD response could be explained by an increased rate of vasoactive signal decay and decreased transit rate of blood, rather than changes in neural activity per se. However, in the absence of other types of neural/hemodynamic data, unique interpretation of HDM parameters is difficult from fMRI data alone, and some brain regions in some tasks (e.g., ipsilateral motor cortex) can show responses that are more difficult to capture using current models. Linear and nonlinear methods for estimating the BOLD response in the sensorimotor task from a large dataset show important effects of adult age on response features and biophysical parameters, some of which suggest age effects may be largely vascular rather than neural.