Michael P. Jones

Bio: Michael P. Jones is an academic researcher from Macquarie University. The author has contributed to research in topics: Irritable bowel syndrome & Population. The author has an hindex of 90, co-authored 707 publications receiving 29327 citations. Previous affiliations of Michael P. Jones include University of Sydney & Jordan University of Science and Technology.

Prevalence of gastrointestinal symptoms associated with diabetes mellitus: a population-based survey of 15,000 adults.

Abstract: Background Gastrointestinal symptoms are reportedly common in diabetes, but a causal link is controversial and adequate population control data are lacking. Objective To determine whether gastrointestinal symptoms are more frequent in persons with diabetes, particularly in those with poor glycemic control. Methods Fifteen thousand adults were mailed a questionnaire (response rate, 60.0%) containing validated questions on the frequency of troublesome gastrointestinal symptoms within the past 3 months, diabetic status, and self-reported glycemic control. The prevalence of 16 symptoms and 5 symptom complexes, reported to occur often or very often, was compared using logistic regression analysis, adjusting for age and sex. Results Overall, 8657 eligible subjects responded; 423 (4.9%) reported having diabetes. Most (94.8%) had type 2 diabetes mellitus. Adjusting for age and sex, all 16 symptoms and the 5 symptom complexes were significantly more frequent in subjects with diabetes compared with controls. An increased prevalence rate of symptoms was significantly associated with poorer levels of glycemic control but not with duration of diabetes or type of diabetic treatment. Conclusions Diabetes mellitus is associated with an increased prevalence of upper and lower gastrointestinal symptoms. This effect may be linked to poor glycemic control but not to duration of diabetes or type of treatment.

Carbon sequestration in temperate grassland ecosystems and the influence of management, climate and elevated CO2

Abstract: Contents I. Introduction 2 II. Carbon in temperate grasslands 2 III. The process of carbon sequestration in soils 4 IV. Tracking carbon movement 9 V. Models of soil carbon dynamics 10 VI. Management effects on carbon sequestration 11 VII. Climate-change effects on carbon sequestration 12 VIII. Response to elevated CO2 13 IX. Conclusions 14 References 14 Summary The substantial stocks of carbon sequestered in temperate grassland ecosystems are located largely below ground in roots and soil. Organic C in the soil is located in discrete pools, but the characteristics of these pools are still uncertain. Carbon sequestration can be determined directly by measuring changes in C pools, indirectly by using 13C as a tracer, or by simulation modelling. All these methods have their limitations, but long-term estimates rely almost exclusively on modelling. Measured and modelled rates of C sequestration range from 0 to > 8 Mg C ha−1 yr−1. Management practices, climate and elevated CO2 strongly influence C sequestration rates and their influence on future C stocks in grassland soils is considered. Currently there is significant potential to increase C sequestration in temperate grassland systems by changes in management, but climate change and increasing CO2 concentrations in future will also have significant impacts. Global warming may negate any storage stimulated by changed management and elevated CO2, although there is increasing evidence that the reverse could be the case.

The brain–gut pathway in functional gastrointestinal disorders is bidirectional: a 12-year prospective population-based study

Abstract: Objective Psychological factors are known to be associated with functional gastrointestinal disorders (FGIDs) including irritable bowel syndrome (IBS) and functional dyspepsia (FD). No prospective studies have evaluated whether it is the brain (eg, via anxiety) that drives gut symptoms, or whether gut dysfunction precipitates the central nervous system features such as anxiety. In a 12-year longitudinal, prospective, population-based study, we aimed to determine the directionality of the brain–gut mechanism in FGIDs. Design Participants (n=1775) were a random population sample from Australia who responded to a survey on FGIDs in 1997 and agreed to be contacted for future research; 1002 completed the 12-year follow-up survey (response rate =60%), with 217, 82 and 45 people meeting Rome II for new onset FGIDs, IBS and FD, respectively. Anxiety and depression were measured using the Delusions Symptom States Inventory at baseline and follow-up. Results Among people free of a FGID at baseline, higher levels of anxiety (OR 1.11; 95% CI 1.03 to 1.19, p=0.006) but not depression at baseline was a significant independent predictor of developing new onset FGIDs 12 years later. Among people who did not have elevated levels of anxiety and depression at baseline, those with a FGID at baseline had significantly higher levels of anxiety and depression at follow-up (mean difference coefficient 0.76, p Conclusions The central nervous system and gut interact bidirectionally in FGIDs.

The PRISMA Statement for Reporting Systematic Reviews and Meta-Analyses of Studies That Evaluate Health Care Interventions: Explanation and Elaboration

Abstract: Systematic reviews and meta-analyses are essential to summarize evidence relating to efficacy and safety of health care interventions accurately and reliably. The clarity and transparency of these reports, however, is not optimal. Poor reporting of systematic reviews diminishes their value to clinicians, policy makers, and other users. Since the development of the QUOROM (QUality Of Reporting Of Meta-analysis) Statement—a reporting guideline published in 1999—there have been several conceptual, methodological, and practical advances regarding the conduct and reporting of systematic reviews and meta-analyses. Also, reviews of published systematic reviews have found that key information about these studies is often poorly reported. Realizing these issues, an international group that included experienced authors and methodologists developed PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) as an evolution of the original QUOROM guideline for systematic reviews and meta-analyses of evaluations of health care interventions. The PRISMA Statement consists of a 27-item checklist and a four-phase flow diagram. The checklist includes items deemed essential for transparent reporting of a systematic review. In this Explanation and Elaboration document, we explain the meaning and rationale for each checklist item. For each item, we include an example of good reporting and, where possible, references to relevant empirical studies and methodological literature. The PRISMA Statement, this document, and the associated Web site (http://www.prisma-statement.org/) should be helpful resources to improve reporting of systematic reviews and meta-analyses.

The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate healthcare interventions: explanation and elaboration

Abstract: Systematic reviews and meta-analyses are essential to summarise evidence relating to efficacy and safety of healthcare interventions accurately and reliably. The clarity and transparency of these reports, however, are not optimal. Poor reporting of systematic reviews diminishes their value to clinicians, policy makers, and other users. Since the development of the QUOROM (quality of reporting of meta-analysis) statement—a reporting guideline published in 1999—there have been several conceptual, methodological, and practical advances regarding the conduct and reporting of systematic reviews and meta-analyses. Also, reviews of published systematic reviews have found that key information about these studies is often poorly reported. Realising these issues, an international group that included experienced authors and methodologists developed PRISMA (preferred reporting items for systematic reviews and meta-analyses) as an evolution of the original QUOROM guideline for systematic reviews and meta-analyses of evaluations of health care interventions. The PRISMA statement consists of a 27-item checklist and a four-phase flow diagram. The checklist includes items deemed essential for transparent reporting of a systematic review. In this explanation and elaboration document, we explain the meaning and rationale for each checklist item. For each item, we include an example of good reporting and, where possible, references to relevant empirical studies and methodological literature. The PRISMA statement, this document, and the associated website (www.prisma-statement.org/) should be helpful resources to improve reporting of systematic reviews and meta-analyses.

Forecasting, Structural Time Series Models and the Kalman Filter

Abstract: In this book, Andrew Harvey sets out to provide a unified and comprehensive theory of structural time series models. Unlike the traditional ARIMA models, structural time series models consist explicitly of unobserved components, such as trends and seasonals, which have a direct interpretation. As a result the model selection methodology associated with structural models is much closer to econometric methodology. The link with econometrics is made even closer by the natural way in which the models can be extended to include explanatory variables and to cope with multivariate time series. From the technical point of view, state space models and the Kalman filter play a key role in the statistical treatment of structural time series models. The book includes a detailed treatment of the Kalman filter. This technique was originally developed in control engineering, but is becoming increasingly important in fields such as economics and operations research. This book is concerned primarily with modelling economic and social time series, and with addressing the special problems which the treatment of such series poses. The properties of the models and the methodological techniques used to select them are illustrated with various applications. These range from the modellling of trends and cycles in US macroeconomic time series to to an evaluation of the effects of seat belt legislation in the UK.