| 1. |
- Fisher, Rosie A., et al.
(författare)
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Vegetation demographics in Earth System Models : A review of progress and priorities
- 2018
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 24:1, s. 35-54
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Forskningsöversikt (refereegranskat)abstract
- Numerous current efforts seek to improve the representation of ecosystem ecology and vegetation demographic processes within Earth System Models (ESMs). These developments are widely viewed as an important step in developing greater realism in predictions of future ecosystem states and fluxes. Increased realism, however, leads to increased model complexity, with new features raising a suite of ecological questions that require empirical constraints. Here, we review the developments that permit the representation of plant demographics in ESMs, and identify issues raised by these developments that highlight important gaps in ecological understanding. These issues inevitably translate into uncertainty in model projections but also allow models to be applied to new processes and questions concerning the dynamics of real-world ecosystems. We argue that stronger and more innovative connections to data, across the range of scales considered, are required to address these gaps in understanding. The development of first-generation land surface models as a unifying framework for ecophysiological understanding stimulated much research into plant physiological traits and gas exchange. Constraining predictions at ecologically relevant spatial and temporal scales will require a similar investment of effort and intensified inter-disciplinary communication.
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| 2. |
- Dietze, Paul, et al.
(författare)
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Correlates of alcohol consumption on heavy drinking occasions of young risky drinkers : event versus personal characteristics
- 2017
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Ingår i: Addiction. - : Wiley. - 0965-2140 .- 1360-0443. ; 112:8, s. 1369-1377
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Tidskriftsartikel (refereegranskat)abstract
- Aims Risky single-occasion drinking (RSOD) by young people is a serious public health issue, yet little is known about the specific circumstances of risky drinking occasions. This study examined the independent effects of event- and individual-specific variables on RSOD. Design Longitudinal cohort study measuring self-reported RSOD and event- and individual-specific variables across two drinking occasions approximately 1 year apart. Setting Metropolitan Melbourne, Australia. Participants A sample of 710 young risky drinkers aged between 18 and 25years and defined as engaging in risky drinking practices (males: consumed alcohol in excess of 10 Australian Standard Drinks (ASD: 10g ethanol) in a single occasion in the previous year; females: consumed alcohol in excess of seven ASD for females in a single occasion in the previous year). Measurements Random digit-dial telephone landline survey of the most recent heavy drinking occasion and socio-demographic variables. The primary outcome was the log of the total drinks consumed in the most recent heavy drinking occasion. Event-specific (e.g. number of drinking locations) and time-varying (e.g. weekly income) and time-invariant (e.g. sex) individual-specific variables were examined as correlates of total drinks consumed. Findings Changes in event-specific characteristics including the length of the drinking occasion (Likelihood Ratio (2)(2)=24.4, P<0.001), the number of drinking locations (Wald (2)((1))=7.6, P=0.006) and the number of different drink types (Wald (2)((1))=13.6, P<0.001) were associated with increases in total drinks consumed, after adjustment for time-invariant and time-variant individual-specific variables such as gender, income level and weekly consumption. Few other effects were noted. Conclusions Event-specific characteristics are important predictors of the number of drinks consumed during risky single occasion drinking (RSOD) and illustrate the importance of event contexts when considering interventions targeting RSOD. The total number of drinks consumed in a RSOD session appears to rise independently with the duration of the drinking event, the number of drinking locations and the number of different types of beverage consumed.
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| 3. |
- Wright, Cassandra, et al.
(författare)
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Mobile Phone-Based Ecological Momentary Intervention to Reduce Young Adults' Alcohol Use in the Event : A Three-Armed Randomized Controlled Trial
- 2018
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Ingår i: JMIR mhealth and uhealth. - : JMIR Publications Inc.. - 2291-5222. ; 6:7
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Tidskriftsartikel (refereegranskat)abstract
- Background: Real-time ecological momentary interventions have shown promising effects in domains other than alcohol use; however, only few studies regarding ecological momentary interventions for alcohol use have been conducted thus far. The increasing popularity of smartphones offers new avenues for intervention and innovation in data collection.Objective: We aimed to test the efficacy of an ecological momentary intervention, comprising mobile Web-based ecological momentary assessments (EMAs) and text messaging (short message service, SMS) brief interventions, delivered during drinking events using participants' mobile phones.Methods: We conducted a three-armed randomized controlled trial to assess the effect of a mobile Web-based ecological momentary assessment with texting feedback on self-reported alcohol consumption and alcohol-related harms in young adults. Participants were enrolled from an existing observational cohort study of young adults screened for risky drinking behavior. The intervention group (ecological momentary intervention group) completed repeated ecological momentary assessments during 6 drinking events and received immediate texting-based feedback in response to each ecological momentary assessment. The second group (ecological momentary assessment group) completed ecological momentary assessments without the brief intervention, and the third did not receive any contact during the trial period. Recent peak risky single-occasion drinking was assessed at the baseline and follow-up using telephone interviews. We used a random effects mixed modeling approach using maximum likelihood estimation to provide estimates of differences in mean drinking levels between groups between baseline and 12-week follow-up.Results: A total of 269 participants were randomized into the 3 groups. The ecological momentary intervention group exhibited a small and nonsignificant increase between baseline and follow-up in (geometric) the mean number of standard drinks consumed at the most recent heavy drinking occasion (mean 12.5 vs 12.7). Both ecological momentary assessment and control groups exhibited a nonsignificant decrease (ecological momentary assessment: mean 13.8 vs 11.8; control: mean 12.3 vs 11.6); these changes did not differ significantly between groups (Wald chi(2)(2) 1.6; P=. 437) and the magnitude of the effects of the intervention were markedly small. No other significant differences between groups on measures of alcohol consumption or related harms were observed. The intervention acceptability was high despite the technical problems in delivery.Conclusions: With a small number of participants, this study showed few effects of an SMS-based brief intervention on peak risky single-occasion drinking. Nevertheless, the study highlights areas for further investigation into the effects of EMI on young adults with heavy alcohol consumption.
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| 4. |
- De Kauwe, Martin G., et al.
(författare)
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Forest water use and water use efficiency at elevated CO2: a model-data intercomparison at two contrasting temperate forest FACE sites
- 2013
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 19:6, s. 1759-1779
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Tidskriftsartikel (refereegranskat)abstract
- Predicted responses of transpiration to elevated atmospheric CO2 concentration (eCO2) are highly variable amongst process-based models. To better understand and constrain this variability amongst models, we conducted an intercomparison of 11 ecosystem models applied to data from two forest free-air CO2 enrichment (FACE) experiments at Duke University and Oak Ridge National Laboratory. We analysed model structures to identify the key underlying assumptions causing differences in model predictions of transpiration and canopy water use efficiency. We then compared the models against data to identify model assumptions that are incorrect or are large sources of uncertainty. We found that model-to-model and model-to-observations differences resulted from four key sets of assumptions, namely (i) the nature of the stomatal response to elevated CO2 (coupling between photosynthesis and stomata was supported by the data); (ii) the roles of the leaf and atmospheric boundary layer (models which assumed multiple conductance terms in series predicted more decoupled fluxes than observed at the broadleaf site); (iii) the treatment of canopy interception (large intermodel variability, 215%); and (iv) the impact of soil moisture stress (process uncertainty in how models limit carbon and water fluxes during moisture stress). Overall, model predictions of the CO2 effect on WUE were reasonable (intermodel =approximately 28%+/- 10%) compared to the observations (=approximately 30%+/- 13%) at the well-coupled coniferous site (Duke), but poor (intermodel =approximately 24%+/- 6%; observations =approximately 38%+/- 7%) at the broadleaf site (Oak Ridge). The study yields a framework for analysing and interpreting model predictions of transpiration responses to eCO2, and highlights key improvements to these types of models.
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| 5. |
- Jiang, Heng, et al.
(författare)
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Alcohol Consumption and Liver Disease in Australia : A Time Series Analysis of the Period 1935–2006
- 2014
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Ingår i: Alcohol and Alcoholism. - : Oxford University Press (OUP). - 0735-0414 .- 1464-3502. ; 49:3, s. 363-368
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Tidskriftsartikel (refereegranskat)abstract
- Aims: The aim of the study was to examine for Australia whether the link between population alcohol consumption and liver disease mortality varies over time, using 71 years of data. Methods: Overall and gender-specific rates of liver disease mortality were analysed in relation to total alcohol consumption as well as for different beverage types by using autoregressive integrated moving average (ARIMA) time series methods. Separate models were developed for the entire time period and for two sub-periods (1935–1975, 1976–2006). Results: A 1-l increase in adult per capita consumption of pure alcohol led to a rise of ∼10% in overall liver disease mortality rates and a 11 and 9% increase in female and male liver disease mortality, respectively. The strength of the relationship between per capita consumption and liver disease mortality diminished over time. Spirits consumption was found to be the main driving factor in liver mortality rates between 1935 and 1975, while beer consumption was found to be the most significant predictor in liver diseases in the last three decades. In a comparative perspective, the effect of per capita alcohol consumption on liver disease in Australia is similar to the USA, Southern and Eastern Europe countries, but weaker than in Canada and western European countries. Conclusion: An increase in per capita alcohol consumption in Australia is likely to lead to an increase in liver disease. Changes in the most important beverage over the study period suggest substantial shifts in drinking patterns and preferences among the heaviest Australian drinkers.
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| 6. |
- Wright, Cassandra, et al.
(författare)
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Effectiveness of an Ecological Momentary Intervention for Reducing Risky Alcohol Consumption Among Young Adults : Protocol for a Three-Arm Randomized Controlled Trial
- 2020
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Ingår i: JMIR Research Protocols. - : JMIR Publications Inc.. - 1929-0748. ; 9:3
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Tidskriftsartikel (refereegranskat)abstract
- Background: Recent research has investigated the utility of mobile phone-delivered interventions for reducing risky single-occasion drinking, also known as binge drinking. In the past five years, focus has been placed on ecological momentary interventions (EMIs), which aim to deliver intervention content in correspondence to real-time assessments of behavior, also known as ecological momentary assessments (EMAs).Objective: This study aims to assess the effect of a fully automated, tailored, mobile phone-delivered EMI termed Mobile Intervention for Drinking in Young people (MIDY) on young people's risky single-occasion drinking behavior.Methods: We will use a three-armed randomized controlled trial design to determine the impact of MIDY on peak consumption of alcohol among young people. A list of mobile telephone numbers for random digit dialing will be generated, and researchers will telephone potential participants to screen for eligibility. Participants will be randomized into one of three intervention groups. For 6 weeks, EMI, EMA, and attention control groups will complete hourly EMA surveys on their mobile phones on Friday and Saturday nights. EMI participants will receive personalized feedback in the form of text messages corresponding to their EMA survey responses, which focus on alcohol consumption, spending, and mood. EMA participants will not receive feedback. A third group will also complete EMA and receive feedback text messages at the same time intervals, but these will be focused on sedentary behavior and technology use. All groups will also complete a short survey on Saturday and Sunday mornings, with the primary outcome measure taken on Sunday mornings. A more detailed survey will be sent on the final Sunday of the 6-week period, and then again 1 year after recruitment.Results: The primary outcome measure will be an observed change (ie, reduction) in the mean peak number of drinks consumed in a single night over the 6-week intervention period between the EMI and attention control groups as measured in the weekly EMA. We expect to see a greater reduction in mean peak drinking in the EMI group compared to that in the attention control group. As a secondary aim, we will assess whether mean peak drinking is reduced in the EMA group compared to the attention control group. We will use a random-effects mixed-modeling approach using maximum-likelihood estimation to provide estimates of differences in peak drinking across time periods between those receiving the intervention (EMI) and attention control participants. An intention-to-treat approach will be taken for the analysis. Individuals and study groups will be modeled as random and fixed factors, respectively.Conclusions: This study extends our previous work investigating the efficacy of a mobile EMI (MIDY) for reducing risky drinking among young adults in Australia, and will add to the expanding literature on the use of mobile interventions for reducing risky alcohol consumption.
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| 7. |
- Zaehle, Soenke, et al.
(författare)
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Evaluation of 11 terrestrial carbon-nitrogen cycle models against observations from two temperate Free-Air CO2 Enrichment studies
- 2014
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Ingår i: New Phytologist. - : Wiley. - 1469-8137 .- 0028-646X. ; 202:3, s. 803-822
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Tidskriftsartikel (refereegranskat)abstract
- We analysed the responses of 11 ecosystem models to elevated atmospheric [CO2] (eCO(2)) at two temperate forest ecosystems (Duke and Oak Ridge National Laboratory (ORNL) Free-Air CO2 Enrichment (FACE) experiments) to test alternative representations of carbon (C)-nitrogen (N) cycle processes. We decomposed the model responses into component processes affecting the response to eCO(2) and confronted these with observations from the FACE experiments. Most of the models reproduced the observed initial enhancement of net primary production (NPP) at both sites, but none was able to simulate both the sustained 10-yr enhancement at Duke and the declining response at ORNL: models generally showed signs of progressive N limitation as a result of lower than observed plant N uptake. Nonetheless, many models showed qualitative agreement with observed component processes. The results suggest that improved representation of above-ground-below-ground interactions and better constraints on plant stoichiometry are important for a predictive understanding of eCO(2) effects. Improved accuracy of soil organic matter inventories is pivotal to reduce uncertainty in the observed C-N budgets. The two FACE experiments are insufficient to fully constrain terrestrial responses to eCO(2), given the complexity of factors leading to the observed diverging trends, and the consequential inability of the models to explain these trends. Nevertheless, the ecosystem models were able to capture important features of the experiments, lending some support to their projections.
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