Effect of a weight-loss program on mental stress-induced cardiovascular responses and recovery

Objective: We assessed the effect of weight loss on blood pressure (BP) and pulse rate during rest, psychological stress, and recovery after stress.

Methods: Two groups of men completed two mental stress tests 12 wk apart. The control group continued their usual diet, whereas the weight-loss group underwent a dietary weight-loss program in which they were randomized to a high-fruit/vegetable and low-fat dairy diet or a low-fat diet.

Results: Fifty-five men with a baseline BP of 125.9 ± 6.9/83.6 ± 7.1 mmHg (mean ± SD) completed the study (weight-loss group, n = 28; control group, n = 27). The weight-loss group lost weight (mean ± SEM, −4.3 ± 0.3 versus +0.4 ± 0.4 kg, P = 0.001) compared with controls and had a significant decrease in resting systolic BP (SBP; −2.0 ± 1.1% versus +2.0 ± 1.1%, P < 0.05). There was a greater decrease in SBP (P < 0.05) and pulse rate (P < 0.05) at all time points during the stress test in the weight loss compared with the control group. At week 12, SBP in 23 (82%) subjects in the weight-loss group and 24 (89%) in the control group returned to resting levels, with recovering levels in the weight-loss group returning to resting levels 6.1 ± 2.6 min earlier than in the control group (P < 0.05). There was an overall greater decrease in diastolic BP (DBP; P < 0.05) and DBP during recovery up to 27 min after stress (P < 0.05) in the high-fruit/vegetable and low-fat dairy diet group (n = 14) compared with the low-fat diet group (n = 14).

Conclusion: A 5% loss of weight decreased BP during rest and returned SBP to resting levels faster, thus decreasing the period of increased BP as a result of mental stress, which is likely to lower the risk of cardiovascular disease in the long term.

A medium-temperature solar thermal power system and its efficiency optimisation

This paper firstly expounds that the reheat-regenerative Rankine power cycle is a suitable cycle for the parabolic trough collector, a popular kind of collector in the power industry. In a thermal power cycle, the higher the temperature at which heat is supplied, the higher the efficiency of the cycle. On the other hand, for a given kind of collector at the same exiting temperature, the higher the temperature of the fluid entering the collector, the lower the efficiency of the collector. With the same exiting temperature of the solar field and the same temperature differences at the hottest end of the superheater/reheater and at the pinch points in the heat exchangers (e.g., the boiler) in the cycle, the efficiencies of the system are subject to the temperature of the fluid entering the collector or the saturation temperature at the boiler. This paper also investigates the optimal thermal and exergetic efficiencies for the combined system of the power cycle and collector. To make most advantage of the collector, the exiting fluid is supposed to be at the maximum temperature the collector can harvest. Hence, the thermal and exergetic efficiencies of the system are related to the saturation temperature at the boiler here.

Environmental management system and electronic communication : Is it the need of the hour?

Implementation and certification of Environmental Management Systems (EMS) is a reality for many businesses. Communication with an organisation’s stakeholders is a required element of any EMS. In the last five years companies have steadily moved towards integrating their different management systems, such as quality, environmental, and occupational health and safety, in an attempt to reduce their costs and increase efficiency. Legislation requires extensive reporting in each of these areas, so compliance is another important driver. During this period, communication by digital technology, or electronic communication, has gained prominence and acceptance amongst all groups of people including businesses primarily as a means to disseminate crucial EMS information to geographically diverse employees in a cost effective and instantaneous manner. Some perspectives have emerged to suggest that change processes in organisations may be hindered or helped in various ways through the application of digital technology in EMS. There are, however, gaps in the literature that document the impact and effectiveness of electronic communication amongst EMS stakeholders. In this paper we will discuss employees as one of the major stakeholders and whether the move to electronic communication has been assisting or hindering transformations in awareness and understanding of issues amongst employees. We highlight opportunities and challenges presented by an increased use of electronic communication in light of the environmental and climate change debates, which underpin EMS.

A systematic policy approach to changing the food system and physical activity environments to prevent obesity

As obesity prevention becomes an increasing health priority in many countries, including Australia
and New Zealand, the challenge that governments are now facing is how to adopt a systematic
policy approach to increase healthy eating and regular physical activity. This article sets out a
structure for systematically identifying areas for obesity prevention policy action across the food
system and full range of physical activity environments. Areas amenable to policy intervention can
be systematically identified by considering policy opportunities for each level of governance (local,
state, national, international and organisational) in each sector of the food system (primary
production, food processing, distribution, marketing, retail, catering and food service) and each
sector that influences physical activity environments (infrastructure and planning, education,
employment, transport, sport and recreation). Analysis grids are used to illustrate, in a structured
fashion, the broad array of areas amenable to legal and regulatory intervention across all levels of
governance and all relevant sectors. In the Australian context, potential regulatory policy
intervention areas are widespread throughout the food system, e.g., land-use zoning (primary
production within local government), food safety (food processing within state government), food
labelling (retail within national government). Policy areas for influencing physical activity are
predominantly local and state government responsibilities including, for example, walking and
cycling environments (infrastructure and planning sector) and physical activity education in schools
(education sector). The analysis structure presented in this article provides a tool to systematically
identify policy gaps, barriers and opportunities for obesity prevention, as part of the process of
developing and implementing a comprehensive obesity prevention strategy. It also serves to
highlight the need for a coordinated approach to policy development and implementation across
all levels of government in order to ensure complementary policy action.

Monitoring the performance of a microkernel based operating system and supported applications

The message passing microkernel based operating system is a class of operating system in which the policies are implemented using servers whose co-operation is supported by using a small hardware dependent layer called a microkernel. This thesis addresses the issue of reducing the performance deficiency by documenting the synthesis, development, implementation and assessment of a methodology and mechanisms for monitoring the performance of a message passing microkernel based operating system and supported processes. The methodology has been extensively evaluated to ensure that it can be used successfully to monitor performance.

Nitric oxide and vascular regulation in fishes and amphibians

Nitric oxide is an important molecule in the regulation of the cardiovascular system and blood pressure. This research provided new insights into the evolution of nitric oxide control of blood vessels by showing how nitric oxide signalling causes vasodilation in the circulation of amphibians and fishes.

A generic virtual reality interaction system and its extensions using the common object request broker architecture (CORBA)

The paper describes the design and implementation of an immersive Virtual Reality (VR) interaction system. The system aims to provide a flexible mechanism for programmers to implement interaction in their VR applications, making good use of all accepted practices in the field. The paper further describes how the system was extended to a multi-user system using the CORBA middleware layer.