Towards global benchmarking of food environments and policies to reduce obesity and diet-related non-communicable diseases : design and methods for nation-wide surveys

Introduction: 

Design and rationale of a 16-week adjunctive randomized placebo-controlled trial of mitochondrial agents for the treatment of bipolar depression

Objective: Bipolar disorder places a significant burden on individuals, caregivers and family, and the broader community. Current treatments are believed to be more effective against manic symptoms, leaving a shortfall in recovery during the depressive phase of the illness. The current study draws on recent evidence suggesting that, in addition to increased oxidative load, alterations in mitochondrial function occur in bipolar disorder. Methods: This 16-week study aims to explore the potential benefits of N-acetylcysteine (NAC) alone or in combination (CT) with selected nutraceuticals believed to enhance mitochondrial function. The study includes adults diagnosed with bipolar disorder currently experiencing an episode of depression. Participants are asked to take NAC, CT, or placebo in addition to any usual treatments. A post-discontinuation visit is conducted 4 weeks following the treatment phase. Results: The primary outcome of the study will be mean change on the Montgomery-Asberg Depression Rating Scale. Secondary outcomes include functioning, substance use, mania ratings, and quality of life. Blood samples will be collected at baseline and week 16 to explore biochemical alterations following treatment. Conclusion: This study may provide a novel adjunctive treatment for bipolar depression. Analysis of biological samples may assist in understanding the therapeutic benefits and the underlying etiology of bipolar depression. Trial registration: Australian and New Zealand Clinical Trial Registry ACTRN12612000830897.

On the multicast lifetime of WANETs with multibeam antennas : Formulation, algorithms, and analysis

We explore the multicast lifetime capacity of energy-limited wireless ad hoc networks using directional multibeam antennas by formulating and solving the corresponding optimization problem. In such networks, each node is equipped with a practical smart antenna array that can be configured to support multiple beams with adjustable orientation and beamwidth. The special case of this optimization problem in networks with single beams have been extensively studied and shown to be NP-hard. In this paper, we provide a globally optimal solution to this problem by developing a general MILP formulation that can apply to various configurable antenna models, many of which are not supported by the existing formulations. In order to study the multicast lifetime capacity of large-scale networks, we also propose an efficient heuristic algorithm with guaranteed theoretical performance. In particular, we provide a sufficient condition to determine if its performance reaches optimum based on the analysis of its approximation ratio. These results are validated by experiments as well. The multicast lifetime capacity is then quantitatively studied by evaluating the proposed exact and heuristic algorithms using simulations. The experimental results also show that using two-beam antennas can exploit most lifetime capacity of the networks for multicast communications. © 2013 IEEE.

Management control systems and organisational learning: the effects of design and use

Purpose – The purpose of this paper is to present a study on relationships between the design of management control systems (MCS), the use of MCS and organisational learning (OL). Design/methodology/approach – This study adopted a survey method. A written questionnaire was prepared and mailed out to collect quantitative data. After analysis of the empirical results, follow-up interviews were conducted to develop a deeper understanding of the empirical results. Findings – Findings of the study show that both the design and use of MCS are significantly associated with levels of OL activities in organisations, and the use of MCS is found to be a more influential factor in OL. Originality/value – This paper contributes to the accounting literature by providing empirical evidence on the relative impacts of the design and use of MCS on OL activities in organisations and the interaction between the design and use of MCS in influencing OL.

Characterizing problematic hypoglycaemia: iterative design and preliminary psychometric validation of the Hypoglycaemia Awareness Questionnaire (HypoA-Q)

AIMS: To design and conduct preliminary validation of a measure of hypoglycaemia awareness and problematic hypoglycaemia, the Hypoglycaemia Awareness Questionnaire.

METHODS: Exploratory and cognitive debriefing interviews were conducted with 17 adults (nine of whom were women) with Type 1 diabetes (mean ± sd age 48±10 years). Questionnaire items were modified in consultation with diabetologists/psychologists. Psychometric validation was undertaken using data from 120 adults (53 women) with Type 1 diabetes (mean ± sd age 44±16 years; 50% with clinically diagnosed impaired awareness of hypoglycaemia), who completed the following questionnaires: the Hypoglycaemia Awareness Questionnaire, the Gold score, the Clarke questionnaire and the Problem Areas in Diabetes questionnaire.

RESULTS: Iterative design resulted in 33 items eliciting answers on awareness of hypoglycaemia when awake/asleep and hypoglycaemia frequency, severity and impact (healthcare utilization). Psychometric analysis identified three subscales reflecting 'impaired awareness', 'symptom level' and 'symptom frequency'. Convergent validity was indicated by strong correlations between the impaired awareness subscale and existing measures of awareness: (Gold: rs =0.75, P<0.01; Clarke: rs =0.76, P<0.01). Divergent validity was indicated by weaker correlations with diabetes-related distress (Problem Areas in Diabetes: rs =0.25, P<0.01) and HbA1c (rs =-0.05, non-significant). The impaired awareness subscale and other items discriminated between those with impaired and intact awareness (Gold score). The impaired awareness subscale and other items contributed significantly to models explaining the occurrence of severe hypoglycaemia and hypoglycaemia when asleep.

CONCLUSIONS: This preliminary validation shows the Hypoglycaemia Awareness Questionnaire has robust face and content validity; satisfactory structure; internal reliability; convergent, divergent and known groups validity. The impaired awareness subscale and other items contribute significantly to models explaining recall of severe and nocturnal hypoglycaemia. Prospective validation, including determination of a threshold to identify impaired awareness, is now warranted.

Design and conduct of a pragmatic randomized controlled trial to enhance smoking-cessation outcomes with exercise: The Fit2Quit study

Background: Most smokers want to stop smoking and many try to quit. However abstinence rates are low and most smokers do not manage to abstain for even a week. Relapse to smoking can be related to the occurrence of tobacco withdrawal symptoms (e.g., sleep disturbance, irritability, and craving) and weight gain. If regular exercise mitigates these effects it could have potential as an aid to smoking cessation. The aim of the Fit2Quit study is to determine the effects of a home and community-based exercise intervention on smoking abstinence at six months when used as an adjunct to usual care (telephone smoking-cessation counseling and nicotine replacement therapy; NRT). Methods/design: A prospective parallel two-arm randomized controlled trial. Participants (n = 1400, 700 per arm) will be randomized to a structured home and community-based exercise program plus usual care (behavioral counseling and NRT) or to usual-care alone. It is targeted that at least 25% of the sample will be of Mori ethnicity (New Zealand indigenous). Outcomes to be measured using intention-to-treat analysis include: seven-day point prevalence of smoking abstinence verified by salivary cotinine (primary outcome); 6 months continuous abstinence; body mass index (BMI); cardio-respiratory fitness; physical activity levels; and cost effectiveness. Discussion: The Fit2Quit study is an example of a large, pragmatic randomized controlled trial in a community setting. Specific components of the exercise intervention are outlined in detail. Trial registration: Australian New Zealand Clinical Trials Registry ACTRN12609000637246.

Design and simulation of a low-actuation-voltage MEMS switch

This paper presents a low-actuation-voltage micro-electromechanical system (MEMS) capacitive shunt switch which has a very large bandwidth (4 GHz to 24 GHz). In this work, the isolation of MEMS switch is improved by adding two short high impedance transmission lines at the beginning and end of a coplanar waveguide (CPW). Simulating the switch demonstrates that a return loss (S11) is less than -26 dB for the entire frequency band, and perfect matching at 20 GHz in upstate position. A ramp dual pulse driver is also designed for reducing the capacitive charge injection for considering the reliability of the switch. The simulation results show that the shifting of voltage due to the capacitive charge is reduced by more than 35% of the initial value. Finally, the dynamic behavior of the MEMS switch is simulated by modal analysis and using CoventorWare to calculate the natural frequencies of the switch and its mode shapes. The switching ON and OFF time are 4.48 and 2.43 μs, respectively, with an actuation voltage of less than 15 V.

Time cumulative complexity modeling and analysis for space-based networks

In this paper, the notion of the cumulative time varying graph (C-TVG) is proposed to model the high dynamics and relationships between ordered static graph sequences for space-based information networks (SBINs). In order to improve the performance of management and control of the SBIN, the complexity and social properties of the SBIN's high dynamic topology during a period of time is investigated based on the proposed C-TVG. Moreover, a cumulative topology generation algorithm is designed to establish the topology evolution of the SBIN, which supports the C-TVG based complexity analysis and reduces network congestions and collisions resulting from traditional link establishment mechanisms between satellites. Simulations test the social properties of the SBIN cumulative topology generated through the proposed C-TVG algorithm. Results indicate that through the C-TVG based analysis, more complexity properties of the SBIN can be revealed than the topology analysis without time cumulation. In addition, the application of attack on the SBIN is simulated, and results indicate the validity and effectiveness of the proposed C-TVG and C-TVG based complexity analysis for the SBIN.