δ15N of lichens reflects the isotopic signature of ammonia source.

Although it is generally accepted that δ15N in lichen reflects predominating N isotope sources in the environment, confirmation of the direct correlation between lichen δ15N and atmospheric δ15N is still missing, especially under field conditions with most confounding factors controlled. To fill this gap and investigate the response of lichens with different tolerance to atmospheric N deposition, thalli of the sensitive Evernia prunastri and the tolerant Xanthoria parietina were exposed for ten weeks to different forms and doses of N in a field manipulation experiment where confounding factors were minimized. During this period, several parameters, namely total N, δ15N and chlorophyll a fluorescence, were measured. Under the experimental conditions, δ15N in lichens quantitatively responded to the δ15N of released gaseous ammonia (NH3). Although a high correlation between the isotopic signatures in lichen tissue and supplied N was found both in tolerant and sensitive species, chlorophyll a fluorescence indicated that the sensitive species very soon lost its photosynthetic functionality with increasing N availability. The most damaging response to the different N chemical forms was observed with dry deposition of NH3, although wet deposition of ammonium ions had a significant observable physiological impact. Conversely, there was no significant effect of nitrate ions on chlorophyll a fluorescence, implying differential sensitivity to dry deposition versus wet deposition and to ammonium versus nitrate in wet deposition. Evernia prunastri was most sensitive to NH3, then NH4+, with lowest sensitivity to NO3-. Moreover, these results confirm that lichen δ15N can be used to indicate the δ15N of atmospheric ammonia, providing a suitable tool for the interpretation of the spatial distribution of NH3 sources in relation to their δ15N signal.

The use of cost-utility analysis for the evaluation of caries prevention: an exploratory case study of two community-based public health interventions in a high-risk population in the UK.

BACKGROUND: Economic evaluations are important tools for decision makers to determine the best allocation of resources in a healthcare system. This study explored the use of economic evaluation in oral health promotion. METHODS: A literature review identified oral health promotion programmes that measured both the health impact and costs of oral health interventions. A decision analysis model was constructed to examine the cost utility of preventing dental caries in 5 and 12-year-old children via tooth brushing schemes and fluoride varnish programmes. The costs per child that would be justified according to the National Institute for Health and Care Excellence's threshold of £20,000 per QALY were calculated. RESULTS: The analysis showed that NICE would consider that the expenditure of £55 per child on supervised tooth brushing, or £100 per child on fluoride varnish application would give sufficient health benefits to be justified according to their threshold. CONCLUSIONS: Greater attention needs to be paid to the collection of robust data on costs for oral health promotion. Dental researchers also urgently need to collect outcome data in a form that can be translated into a Quality of Life measure, so that the true cost effectiveness and value for money achieved through the prevention of dental disease can be recognised and compared to other allocations of resource.

Nitrogen deposition does not enhance Sphagnum decomposition.

Long-term additions of nitrogen (N) to peatlands have altered bryophyte growth, species dominance, N content in peat and peat water, and often resulted in enhanced Sphagnum decomposition rate. However, these results have mainly been derived from experiments in which N was applied as ammonium nitrate (NH4NO3), neglecting the fact that in polluted areas, wet deposition may be dominated either by NO3(-) or NH4(+). We studied effects of elevated wet deposition of NO3(-) vs. NH4(+) alone (8 or 56kgNha(-1)yr(-1) over and above the background of 8kgNha(-1)yr(-1) for 5 to 11years) or combined with phosphorus (P) and potassium (K) on Sphagnum quality for decomposers, mass loss, and associated changes in hummock pore water in an ombrotrophic bog (Whim). Adding N, especially as NH4(+), increased N concentration in Sphagnum, but did not enhance mass loss from Sphagnum. Mass loss seemed to depend mainly on moss species and climatic factors. Only high applications of N affected hummock pore water chemistry, which varied considerably over time. Overall, C and N cycling in this N treated bog appeared to be decoupled. We conclude that moss species, seasonal and annual variation in climatic factors, direct negative effects of N (NH4(+) toxicity) on Sphagnum production, and indirect effects (increase in pH and changes in plant species dominance under elevated NO3(-) alone and with PK) drive Sphagnum decomposition and hummock C and N dynamics at Whim.

The discriminatory value of cardiorespiratory interactions in distinguishing awake from anaesthetised states: a randomised observational study.

Depth of anaesthesia monitors usually analyse cerebral function with or without other physiological signals; non-invasive monitoring of the measured cardiorespiratory signals alone would offer a simple, practical alternative. We aimed to investigate whether such signals, analysed with novel, non-linear dynamic methods, would distinguish between the awake and anaesthetised states. We recorded ECG, respiration, skin temperature, pulse and skin conductivity before and during general anaesthesia in 27 subjects in good cardiovascular health, randomly allocated to receive propofol or sevoflurane. Mean values, variability and dynamic interactions were determined. Respiratory rate (p = 0.0002), skin conductivity (p = 0.03) and skin temperature (p = 0.00006) changed with sevoflurane, and skin temperature (p = 0.0005) with propofol. Pulse transit time increased by 17% with sevoflurane (p = 0.02) and 11% with propofol (p = 0.007). Sevoflurane reduced the wavelet energy of heart (p = 0.0004) and respiratory (p = 0.02) rate variability at all frequencies, whereas propofol decreased only the heart rate variability below 0.021 Hz (p < 0.05). The phase coherence was reduced by both agents at frequencies below 0.145 Hz (p < 0.05), whereas the cardiorespiratory synchronisation time was increased (p < 0.05). A classification analysis based on an optimal set of discriminatory parameters distinguished with 95% success between the awake and anaesthetised states. We suggest that these results can contribute to the design of new monitors of anaesthetic depth based on cardiovascular signals alone.

Impact of preferential sampling on exposure prediction and health effect inference in the context of air pollution epidemiology.

Preferential sampling has been defined in the context of geostatistical modeling as the dependence between the sampling locations and the process that describes the spatial structure of the data. It can occur when networks are designed to find high values. For example, in networks based on the U.S. Clean Air Act monitors are sited to determine whether air quality standards are exceeded. We study the impact of the design of monitor networks in the context of air pollution epidemiology studies. The effect of preferential sampling has been illustrated in the literature by highlighting its impact on spatial predictions. In this paper, we use these predictions as input in a second stage analysis, and we assess how they affect health effect inference. Our work is motivated by data from two United States regulatory networks and health data from the Multi-Ethnic Study of Atherosclerosis and Air Pollution. The two networks were designed to monitor air pollution in urban and rural areas respectively, and we found that the health analysis results based on the two networks can lead to different scientific conclusions. We use preferential sampling to gain insight into these differences. We designed a simulation study, and found that the validity and reliability of the health effect estimate can be greatly affected by how we sample the monitor locations. To better understand its effect on second stage inference, we identify two components of preferential sampling that shed light on how preferential sampling alters the properties of the health effect estimate.

Study of gamma irradiation effect on commercial TiO2 photocatalyst.

The aim of this work is to understand the effect of gamma irradiation on commercial TiO2 photocatalyst for water treatment applications. Previous studies concluded that gamma-irradiation is able to modify the electronic properties of TiO2 based photocatalysts and consequently their photocatalytic performance. However, there are some discrepancies in the literature where on one hand a significant enhancement of the material properties is reported and on the other hand only a weak effect is observed. In this study a surface effect on TiO2 is confirmed by using low and medium gamma irradiation doses.

Can ammonia tolerance amongst lichen functional groups be explained by physiological responses?

Ammonia (NH3) empirical critical levels for Europe were re-evaluated in 2009, based mainly on the ecological responses of lichen communities without acknowledging the physiological differences between oligotrophic and nitrophytic species. Here, we compare a nitrogen sensitive lichen (Evernia prunastri) with a nitrogen tolerant one (Xanthoria parietina), focussing on their physiological response (Fv/Fm) to short-term NH3 exposure and their frequency of occurrence along an NH3 field gradient. Both frequency and Fv/Fm of E. prunastri decreased abruptly above 3 µg m(-3) NH3 suggesting direct adverse effects of NH3 on its photosynthetic performance. By contrast, X. parietina increased its frequency with NH3, despite showing decreased capacity of photosystem II above 50 µg m(-3) NH3, suggesting that the ecological success of X. parietina at ammonia-rich sites might be related to indirect effects of increased nitrogen (NH3) availability. These results highlight the need to establish NH3 critical levels based on oligotrophic lichen species.

Perceptions of emergency department staff of the role of physiotherapists in the system: a qualitative investigation.

OBJECTIVES: To investigate the perceptions of doctors, nurses and physiotherapists of emergency department physiotherapy for acute patients, and explore the scope of its contribution in an otherwise nontraditional allied health setting in Australia. DESIGN: Qualitative investigation using semi-structured interviews. SETTING: A large, metropolitan tertiary hospital with a well-established emergency department physiotherapy/allied health network in place. PARTICIPANTS: Two emergency department doctors, two emergency department nurses and two senior physiotherapists working in an emergency department were recruited purposefully from the study hospital. INTERVENTIONS: Semi-structured interviews lasting from 20 minutes to 1 hour were conducted with each participant by the lead investigator. Data were analysed using NVivo software, coded manually and verified with member checking, facilitating constant case comparisons. RESULTS: Issues explored included defining the role of physiotherapists, uncovering organisational themes from the introduction of physiotherapy into the established emergency department setting, and conflicts around preserving and expanding an allied health identity in a highly-medicalised clinical environment. CONCLUSIONS: Participants described the benefits of having physiotherapists located in the emergency department, and the physiotherapists were eager to advance their roles and responsibilities, but were, at times, restricted by a complicated organisational landscape influencing professional autonomy and capacity for professional advocacy. Ongoing evidence supporting the breadth of physiotherapy practice in the emergency department is needed to further advocate the usefulness of the profession in this acute setting.

Characterizing an ensemble of interacting oscillators: the mean-field variability index.

We introduce a way of characterizing an ensemble of interacting oscillators in terms of their mean-field variability index κ, a dimensionless parameter defined as the variance of the oscillators' mean field r divided by the mean square of r. Based on the assumption that the overall mean field is the sum of a very large number of oscillators, each giving a small contribution to the total signal, we show that κ depends on the mutual interactions between the oscillators, independently of their number or spectral properties. For purely random phasors, or a noninteracting ensemble of oscillators, κ converges on 0.215. Interactions push κ in different directions: lower where there is interoscillator phase coherence, tending to zero for complete phase synchronization, or higher for amplitude synchronization or intermittent synchronization. We calculate κ for several different cases to illustrate its utility, using both numerically simulated data and electroencephalograph signals from the brains of human subjects while awake, while anesthetized, and while undergoing an epileptic fit.

Testing for time-localized coherence in bivariate data.

We present a method for the testing of significance when evaluating the coherence of two oscillatory time series that may have variable amplitude and frequency. It is based on evaluating the self-correlations of the time series. We demonstrate our approach by the application of wavelet-based coherence measures to artificial and physiological examples. Because coherence measures of this kind are strongly biased by the spectral characteristics of the time series, we evaluate significance by estimation of the characteristics of the distribution of values that may occur due to chance associations in the data. The expectation value and standard deviation of this distribution are shown to depend on the autocorrelations and higher order statistics of the data. Where the coherence value falls outside this distribution, we may conclude that there is a causal relationship between the signals regardless of their spectral similarities or differences.

Residential indoor PM2.5 in wood stove homes: follow-up of the Libby changeout program.

UNLABELLED: In 2005 through 2008, a small rural mountain valley community engaged in a woodstove changeout program to address concerns of poor ambient air quality. During this program, we assessed changes to indoor air quality before and after the introduction of a new, lower emission woodstove. We previously reported a >70% reduction in indoor PM(2.5) concentrations in homes following the installation of a new Environmental Protection Agency's-certified stove within the home. We report here on follow-up of the experiences in these and other homes over three winters of sample collection. In 21 homes, we compared pre-changeout PM(2.5) concentrations [mean (s.d.) = 45.0 (33.0) µg/m(3)] to multiple post-changeout measures of PM(2.5) concentrations using a DustTrak. The mean reduction (and 95% confidence interval) from pre-changeout to post-changeout was -18.5 µg/m(3) (-31.9, -5.2), adjusting for ambient PM(2.5) , ambient temperature, and other factors. Findings across homes and across years were highly variable, and a subset of homes did not experience a reduction in PM(2.5) following changeout. Reductions were also observed for organic carbon, elemental carbon, and levoglucosan, but increases were observed for dehydroabietic acid and abietic acid. Despite overall improvements in indoor air quality, the varied response across homes may be due to factors other than the introduction of a new woodstove. PRACTICAL IMPLICATIONS: Biomass combustion is a common source of ambient PM(2.5) in many cold-climate communities. The replacement of older model woodstoves with newer technology woodstoves is a potential intervention strategy to improve air quality in these communities. In addition to ambient air, woodstove changeouts should improve residential indoor air quality. We present results from a multi-winter study to evaluate the efficacy of woodstove changeouts on improving indoor air quality. Reductions in indoor PM(2.5) were evident, but this observation was not consistent across all homes. These findings suggest that other factors beyond the introduction of an improved wood burning device are relevant to improving indoor air quality in wood burning homes.

Glasshouse vs field experiments: do they yield ecologically similar results for assessing N impacts on peat mosses?

• Peat bogs have accumulated more atmospheric carbon (C) than any other terrestrial ecosystem today. Most of this C is associated with peat moss (Sphagnum) litter. Atmospheric nitrogen (N) deposition can decrease Sphagnum production, compromising the C sequestration capacity of peat bogs. The mechanisms underlying the reduced production are uncertain, necessitating multifactorial experiments. • We investigated whether glasshouse experiments are reliable proxies for field experiments for assessing interactions between N deposition and environment as controls on Sphagnum N concentration and production. We performed a meta-analysis over 115 glasshouse experiments and 107 field experiments. • We found that glasshouse and field experiments gave similar qualitative and quantitative estimates of changes in Sphagnum N concentration in response to N application. However, glasshouse-based estimates of changes in production--even qualitative assessments-- diverged from field experiments owing to a stronger N effect on production response in absence of vascular plants in the glasshouse, and a weaker N effect on production response in presence of vascular plants compared to field experiments. • Thus, although we need glasshouse experiments to study how interacting environmental factors affect the response of Sphagnum to increased N deposition, we need field experiments to properly quantify these effects.

The effectiveness of training and support for carers and other professionals on the physical and emotional health and well-being of looked-after children and young people: a systematic review.

Looked-after children and young people (LACYP) are recognized as a high-risk group for behavioural and emotional problems, and additional specialist training for foster carers may reduce such problems. This systematic review aimed to identify and synthesize evidence on the effectiveness of additional training and support provided to approved carers, professionals and volunteers on the physical and emotional health and well-being of LACYP (including problem behaviours and placement stability). Searches of health and social science databases were conducted and records were screened for inclusion criteria. Citation and reference list searches were conducted on included studies. Included studies were synthesized and critically appraised. Six studies were included (five randomized controlled trials and one prospective cohort study), all of which focused on foster carers. Three studies reported a benefit of training and three reported no benefit but no detriment. Those reporting a benefit of training were conducted in the USA, and had longer-duration training, shorter follow-up assessment and recruited carers of younger children than studies that reported no benefit of training, which were conducted in the UK. Whether the difference in results is due to the type of training or to cultural or population differences is unclear. The findings suggest a mixed effect of training for foster carers on problem behaviours of LACYP. The evidence identified appears to suggest that longer-duration training programmes have a beneficial effect on the behaviour problems of LACYP, although future research should examine the impact of training durations and intensity on short-medium and longer-term outcomes of LACYP of different ages. Only training and support for foster carers was identified.

Supporting the transition of looked-after young people to independent living: a systematic review of interventions and adult outcomes.

This systematic review aimed to synthesize evidence on the effectiveness of transition support services (TSSs) that are delivered towards the end of care for looked-after young people (LAYP) on their adult outcomes, including education, employment, substance misuse, criminal and offending behaviour, parenthood, housing and homelessness and health. Searches of health, social science and social care bibliographic databases were conducted and records were screened for relevance. Citation and reference list searches were conducted on included studies. Relevant studies were synthesized and critically appraised. Seven studies were identified (five retrospective and two prospective cohort studies), six of which were conducted in the USA and one in the UK. Overall, LAYP who received TSSs were more likely to complete compulsory education with formal qualifications, be in current employment, be living independently and less likely to be young parents. There was no reported effect of the impact of TSSs on crime or mental health, and mixed findings for homelessness. The range of TSS components investigated and reported varied considerably within and between studies, with limited evidence of long-term outcomes. The literature reviewed offers no reliable conclusions on the effectiveness of TSSs at this time due to variations in research quality and because few formal evaluations of existing TSSs have been conducted, resulting in mixed evidence in terms of positive, negative and neutral impact on outcomes. Further high-quality, robust research to evaluate the effectiveness of TSSs on adult outcomes for young people in the short, medium and longer term is needed to address the health inequalities experienced by this small but vulnerable group and to inform decision making about service provision.

Oscillatory dynamics of vasoconstriction and vasodilation identified by time-localized phase coherence.

We apply wavelet-based time-localized phase coherence to investigate the relationship between blood flow and skin temperature, and between blood flow and instantaneous heart rate (IHR), during vasoconstriction and vasodilation provoked by local cooling or heating of the skin. A temperature-controlled metal plate (approximately 10 cm2) placed on the volar side of the left arm was used to provide the heating and cooling. Beneath the plate, the blood flow was measured by laser Doppler flowmetry and the adjacent skin temperature by a thermistor. Two 1 h datasets were collected from each of the ten subjects. In each case a 30 min basal recording was followed by a step change in plate temperature, to either 24 °C or 42 °C. The IHR was derived from simultaneously recorded ECG. We confirm the changes in the energy and frequency of blood flow oscillations during cooling and heating reported earlier. That is, during cooling, there was a significant decrease in the average frequency of myogenic blood flow oscillations (p < 0.05) and the myogenic spectral peak became more prominent. During heating, there was a significant (p < 0.05) general increase in spectral energy, associated with vasodilation, except in the myogenic interval. Weak phase coherence between temperature and blood flow was observed for unperturbed skin, but it increased in all frequency intervals as a result of heating. It was not significantly affected by cooling. We also show that significant (p < 0.05) phase coherence exists between blood flow and IHR in the respiratory and myogenic frequency intervals. Cooling did not affect this phase coherence in any of the frequency intervals, whereas heating enhanced the phase coherence in the respiratory and myogenic intervals. This can be explained by the reduction in vascular resistance produced by heating, a process where myogenic mechanisms play a key role. We conclude that the mechanisms of vasodilation and vasoconstriction, in response to temperature change, are oscillatory in nature and are independent of central sources of variability.

Evaluation and comparison of three exposure assessment techniques.

This study was conducted to verify the performance of a recently developed subjective rating (SR) exposure assessment technique and to compare estimates made using this and two other techniques (trade mean, or TM, and task-based, or TB, approaches) to measured exposures. Subjects (n = 68) each completed three full-shift noise measurements over 4 months. Individual measured mean exposures were created by averaging each subject's repeated measurements, and TM, TB, and SR estimates were created using noise levels from worksites external to the current study. The bias, precision, accuracy, and absolute agreement of estimates created using the three techniques were evaluated by comparing estimated exposures with measured exposures. Trade mean estimates showed little bias, while neither the TM nor the SR techniques produced unbiased estimates, and the SR estimates showed the greatest bias of the three techniques. Accuracy was essentially equivalent among the three techniques. All three techniques showed poor agreement with measured exposures and were not highly correlated with each other. Estimates from the SR technique generally performed similarly to the TM and TB techniques. Methods to incorporate information from each technique into exposure estimates should be explored.

Detecting the harmonics of oscillations with time-variable frequencies.

A method is introduced for the spectral analysis of complex noisy signals containing several frequency components. It enables components that are independent to be distinguished from the harmonics of nonsinusoidal oscillatory processes of lower frequency. The method is based on mutual information and surrogate testing combined with the wavelet transform, and it is applicable to relatively short time series containing frequencies that are time variable. Where the fundamental frequency and harmonics of a process can be identified, the characteristic shape of the corresponding oscillation can be determined, enabling adaptive filtering to remove other components and nonoscillatory noise from the signal. Thus the total bandwidth of the signal can be correctly partitioned and the power associated with each component then can be quantified more accurately. The method is first demonstrated on numerical examples. It is then used to identify the higher harmonics of oscillations in human skin blood flow, both spontaneous and associated with periodic iontophoresis of a vasodilatory agent. The method should be equally relevant to all situations where signals of comparable complexity are encountered, including applications in astrophysics, engineering, and electrical circuits, as well as in other areas of physiology and biology.

Climatic modifiers of the response to nitrogen deposition in peat-forming Sphagnum mosses: a meta-analysis.

Peatlands in the northern hemisphere have accumulated more atmospheric carbon (C) during the Holocene than any other terrestrial ecosystem, making peatlands long-term C sinks of global importance. Projected increases in nitrogen (N) deposition and temperature make future accumulation rates uncertain. Here, we assessed the impact of N deposition on peatland C sequestration potential by investigating the effects of experimental N addition on Sphagnum moss. We employed meta-regressions to the results of 107 field experiments, accounting for sampling dependence in the data. We found that high N loading (comprising N application rate, experiment duration, background N deposition) depressed Sphagnum production relative to untreated controls. The interactive effects of presence of competitive vascular plants and high tissue N concentrations indicated intensified biotic interactions and altered nutrient stochiometry as mechanisms underlying the detrimental N effects. Importantly, a higher summer temperature (mean for July) and increased annual precipitation intensified the negative effects of N. The temperature effect was comparable to an experimental application of almost 4 g N m(-2) yr(-1) for each 1°C increase. Our results indicate that current rates of N deposition in a warmer environment will strongly inhibit C sequestration by Sphagnum-dominated vegetation.

Factors associated with outcomes for looked-after children and young people: a correlates review of the literature.

In 2008, the Department of Health made a referral to the National Institute for Health and Clinical Excellence and the Social Care Institute for Excellence to develop joint public health guidance on improving the physical and emotional health and well-being of children and young people looked after by the local authority/state. To help inform the decision-making process by identifying potential research questions pertinent to the outcomes of looked-after children and young people (LACYP), a correlates review was undertaken. Iterative searches of health and social science databases were undertaken; searches of reference lists and citation searches were conducted and all included studies were critically appraised. The correlates review is a mapping review conducted using systematic and transparent methodology. Interventions and factors that are associated (or correlated) with outcomes for LACYP were identified and presented as conceptual maps. This review maps the breadth (rather than depth) of the evidence and represents an attempt to use the existing evidence base to map associations between potential risk factors, protective factors, interventions and outcomes for LACYP. Ninety-two studies were included: four systematic reviews, five non-systematic reviews, eight randomized controlled trials, 66 cohort studies and nine cross-sectional studies. The conceptual maps provide an overview of the key relationships addressed in the current literature, in particular, placement stability and emotional and behavioural factors in mediating outcomes. From the maps, there appear to be some key factors that are associated with a range of outcomes, in particular, number of placements, behavioural problems and age at first placement. Placement stability seems to be a key mediator of directional associations. The correlates review identified key areas where sufficient evidence to conduct a systematic review might exist. These were: transition support, training and support for carers and access to services.