A new physarum network based genetic algorithm for bandwidth-delay constrained least-cost multicast routing

Bandwidth-delay constrained least-cost multicast routing is a typical NP-complete problem. Although some swarm-based intelligent algorithms (e.g., genetic algorithm (GA)) are proposed to solve this problem, the shortcomings of local search affect the computational effectiveness. Taking the ability of building a robust network of Physarum network model (PN), a new hybrid algorithm, Physarum network-based genetic algorithm (named as PNGA), is proposed in this paper. In PNGA, an updating strategy based on PN is used for improving the crossover operator of traditional GA, in which the same parts of parent chromosomes are reserved and the new offspring by the Physarum network model is generated. In order to estimate the effectiveness of our proposed optimized strategy, some typical genetic algorithms and the proposed PNGA are compared for solving multicast routing. The experiments show that PNGA has more efficient than original GA. More importantly, the PNGA is more robustness that is very important for solving the multicast routing problem.

A new genetic algorithm based on modified Physarum network model for bandwidth-delay constrained least-cost multicast routing

A mobile ad hoc network is a kind of popular self-configuring network, in which multicast routing under the quality of service constraints, is a significant challenge. Many researchers have proved that such problem can be formulated as a NP-complete problem and proposed some swarm-based intelligent algorithms to solve the optimal solution, such as the genetic algorithm (GA), bees algorithm. However, a lower efficiency of local search ability and weak robustness still limit the computational effectiveness. Aiming to those shortcomings, a new hybrid algorithm inspired by the self-organization of Physarum, is proposed in this paper. In our algorithm, an updating scheme based on Physarum network model (PM) is used for improving the crossover operator of traditional GAs, in which the same parts of parent chromosomes are reserved and the new offspring by the PM is generated. In order to estimate the effectiveness of our proposed optimized scheme, some typical genetic algorithms and their updating algorithms (PMGAs) are compared for solving the multicast routing on four different datasets. The simulation experiments show that PMGAs are more efficient than original GAs. More importantly, the PMGAs are more robustness that is very important for solving the multicast routing problem. Moreover, a series of parameter analyses is used to find a set of better setting for realizing the maximal efficiency of our algorithm.

Cost-effectiveness of adult circumcision in a resource-rich setting for HIV prevention among men who have sex with men

Background.  We examined the effects and cost‐effectiveness of 4 strategies of circumcision in a resource‐rich setting (Australia) in a population of men who have sex with men (MSM).

Method.  We created a dynamic mathematical transmission model and performed an economic analysis to estimate the costs, outcomes, and cost‐effectiveness of different strategies, compared with those of the status quo. Strategies included circumcision of all MSM at age 18 years, circumcision of all MSM aged 35–44 years, circumcision of all insertive MSM aged 18 years, and circumcision of all MSM aged 18 years . All costs are reported in US dollars, with a cost‐effectiveness threshold of $42,000 per quality‐adjusted life‐year.

Results.  We find that 2%–5% of human immunodeficiency virus (HIV) infections would be averted per year, with initial costs ranging from $3.6 million to $95.1 million, depending on the strategy. The number of circumcisions needed to prevent 1 HIV infection would range from 118 through 338. Circumcision of predominately insertive MSM would save $21.7 million over 25 years with a $62.2 million investment. Strategies to circumcise 100% of all MSM and to circumcise MSM aged 35–44 years would be cost‐effective; the latter would require a smaller investment. The least cost‐effective approach is circumcision of young MSM close to their sexual debut. Results are very sensitive to assumptions about the cost of circumcision, the efficacy of circumcision, sexual preferences, and behavioral disinhibition.

Conclusions.  Circumcision of adult MSM may be cost‐effective in this resource‐rich setting. However, the intervention costs are high relative to the costs spent on other HIV prevention programs.

Dietary portfolio approach to reducing the risk of cardiovascular disease : the polymeal revisited

Aims: The Polymeal was first proposed as a 'tastier and safer' alternative to a polypharmacy approach to cardiovascular disease risk reduction. The present study aimed to examine the affordability of the Polymeal, and to propose modifications based on economic considerations, and the latest scientific evidence, to achieve consistency with current public health recommendations.

Methods: Prices for each food component specified in the Polymeal were obtained from a major and independent supermarket chain in a representative middle socioeconomic demographic region of metropolitan Melbourne, Australia. Items included fish (114 g, four times/week), fruits and vegetables (400 g/day), dark chocolate (100 g/day), garlic (2.7 g/day), almonds (68 g/day) and red wine (150 mL/day). Prices were calculated using an average of the major brands, or the most commonly eaten fruits, vegetables or fish. Modifications of the Polymeal were proposed based on published research and public health recommendations since the Polymeal was first proposed.

Results: Average price of the Polymeal was AU$11.89 per day falling to AU$8.46 if the cheapest food items were chosen. Modifications to the Polymeal included: consuming fish oil capsules instead of fish, reduction in the quantity of dark chocolate and removal of red wine. These modifications halved the cost of the Polymeal, while choosing the cheapest food items further lowered the cost to AU$3.49 per day. Modification of the Polymeal gave substantial reductions in both energy and saturated fat (51% and 84%, respectively).

Conclusion: The modified Polymeal is a more affordable variation of the Polymeal, which takes into account current scientific evidence and public health recommendations.

The use of contracting out : a case study of decision-making and organisational learning in local government

One objective of government is to provide services at least cost whilst maintaining or improving service quality. While this may be an important objective, questions are being asked whether services can be provided more efficiently and effectively by the private rather than by the government sector. The shift of service provision from the public to the private sector is known as outsourcing or contracting out. The objective in this study is to critically examine whether the contracting out of services by local government to the private sector is an efficient management practice.

The contracting out of Parks and Grounds Maintenance services for the City of Kingston in the State of Victoria, Australia, is used as an exploratory case study to identify the variables associated with management decision-making in the contracting out process. Factors relevant to the contracting out decision such as the criteria used in selecting a contractor; the evaluation of a contractor’s performance; and any subsequent changes to management practice relating to the contracting out of the services are identified and discussed.

Political forces were found to be an important consideration in the initial contracting out decision, and the selection of a contractor was influenced by the potential to avoid costs. It was also found that under-bidding and associated cost /profit constraints lead to contractors engaging in non-sustainable environmental practices which resulted in the degradation of the local government’s Parks and Gardens assets. A sustainable asset management philosophy as opposed to an avoidable costs approach now underpins the contracting out process to ensure the preservation of such assets. Further, administrative processes have been revised to make tender specifications more prescriptive, critical components of services have been brought back in-house, and management practices have been amended so that a greater degree of control is exercised over contractors’ activities.

Predicting landscape-genetic consequences of habitat loss, fragmentation and mobility for multiple species of woodland birds

Inference concerning the impact of habitat fragmentation on dispersal and gene flow is a key theme in landscape genetics. Recently, the ability of established approaches to identify reliably the differential effects of landscape structure (e.g. land-cover composition, remnant vegetation configuration and extent) on the mobility of organisms has been questioned. More explicit methods of predicting and testing for such effects must move beyond post hoc explanations for single landscapes and species. Here, we document a process for making a priori predictions, using existing spatial and ecological data and expert opinion, of the effects of landscape structure on genetic structure of multiple species across replicated landscape blocks. We compare the results of two common methods for estimating the influence of landscape structure on effective distance: least-cost path analysis and isolation-by-resistance. We present a series of alternative models of genetic connectivity in the study area, represented by different landscape resistance surfaces for calculating effective distance, and identify appropriate null models. The process is applied to ten species of sympatric woodland-dependant birds. For each species, we rank a priori the expectation of fit of genetic response to the models according to the expected response of birds to loss of structural connectivity and landscape-scale tree-cover. These rankings (our hypotheses) are presented for testing with empirical genetic data in a subsequent contribution. We propose that this replicated landscape, multi-species approach offers a robust method for identifying the likely effects of landscape fragmentation on dispersal.

A novel approach to priority-setting for HIV prevention among adults in Uganda

 The study used economic and ethical theory, empirical evidence and local stakeholders views to develop a checklist of features of an ideal approach to priority-setting. This was used to determine the ideal approach for priority-setting for HIV prevention in Uganda. The Assessing Cost-Effectiveness (ACE) approach was determined to be the ideal approach using the checklist developed. A pilot study using the approach determined that in Uganda, blood safety and HIV counselling interventions are the most cost-effective, equitable and acceptable interventions. Mass media interventions were the least cost-effective and affordable, had a weak evidence base but were more acceptable. On the other hand interventions targeting Most-at-risk-populations were cost-effective but least acceptable. The study demonstrates the importance of balancing technical rigor and due process to ensure buy-in by stakeholders.

It's time to determine the cost of a healthy diet in Australia

Economic factors are important determinants of food security. In terms of food access, financial resources determine an individual’s ability to procure food; on the supply side, the cost of food is equally important. The interplay of these two factors, financial resources and cost, is perhaps the most immediate and important determinant of what people do (or do not) put into their shopping trolleys or purchase at the takeaway and ultimately eat – if you cannot afford it you cannot eat it even if you want to!

The cost of storing checkpoints to multiple volatile storage locations using at-least-k semantics

Using the volatile memory of other computers within a system to store checkpoints is an alternative to the traditional approach of using stable storage. The objective of this study is to develop a storage mechanism using at-least-k delivery semantics. This semantics allows data to be saved to a minimum number of computers simultaneously using group communications, without requiring that each group computer successfully acknowledge the receipt. The new storage mechanism is implemented in the GENESIS checkpointing facility v2.0. The results showed that at-least-k storage mechanisms provide low storage latency times; however, the incurred execution overheads on the applications executing within the system are higher than that when using remote stable storage to store checkpoints.

Is a healthy diet affordable and accessible in the city of Yarra, Victoria Australia? An analysis of cost disparity and nutritional choices

This study aimed to examine cost disparity and nutritional choices within the
City of Yarra (Yarra), targeting three suburbs that have low- and high-rise
estates: Richmond, Fitzroy, and Collingwood. The healthy food basket
(HFB) was modeled on the Queensland Healthy Food Access Basket for a
six-person family for a fortnight and was constructed to include food items
that are common to ethnic groups living in Yarra. The HFB food item costs
were sampled across 29 food outlets in Yarra. The average cost of HFB per fortnight
for a family of six was significantly lower in Richmond (Mean = $419.26)
than in Collingwood (Mean = $519.28) and in Fitzroy (Mean = $433.98). While
costs for cereal groups, dairy, meats and alternatives, and non-core were
comparable across the suburbs, significant differences were noticed for fruit,
legumes and vegetables. Geographic location alone explained 54% of the
variance in HFB price (F_2,26 = 15.23, p < 0.001) and 32.7% in the variance of
fruit, vegetable and legumes (F_2,26 = 7.72, p < 0.001). The effect of geographic
location remained consistent after controlling for the type of food
outlets. The type of food outlets had a non-significant effect on the variance
of prices. Richmond had a greater number variety of fruit, vegetables, and
legumes (F_{2, 26} = 5.7, p < 0.01) and an overall lower number of missing items
(F_{2, 26} = 3.9, p < 0.05) than Collingwood and Fitzroy. The diversity of food
available in the three suburbs was more likely to reflect the Vietnamese,
Chinese and East-Timorese shopping pattern than the rest of other ethnic

Food cost and availability in a rural setting in Australia

Introduction: The burden of chronic diseases is rapidly increasing worldwide. In  Australia rural populations have a greater burden of disease. Chronic diseases are largely preventable with diet as a key risk factor. With respect to diet-related chronic disease, dietary risk may be due to poor food access, namely, poor availability and/or the high cost of healthy food. It is likely that poor food access is an issue in rural areas. Objective: To assess food access in rural south-west (SW) Victoria, Australia.

Methods: A total of 53 supermarkets and grocery stores in 42 towns participated in a survey of food cost and availability in the rural area of SW Victoria. The survey assessed availability and cost of a Healthy Food Access Basket (HFAB) which was designed to meet the nutritional needs of a family of 6 for 2 weeks.

Results: Seventy-two percent of the eligible shops in SW Victoria were surveyed. The study found that the complete HFAB was significantly more likely to be available in a town with a chain-owned store (p<0.00). The complete HFAB was less likely to be available from an independently owned store in a town with only one grocery shop (p<0.004). The average cost of the HFAB across SW Victoria was AU$380.30 ± $25.10 (mean ± SD). There was a mean range in difference of cost of the HFAB of $36.92. In particular, high variability was found in the cost of fruits and vegetables.

Conclusions: Cost and availability of healthy food may be compromised in rural areas. Implications: Improvements in food access in rural areas could reduce the high burden of disease suffered by rural communities.

Change in the diet of sooty owls (Tyto tenebricosa) since European settlement: from terrestrial to arboreal prey and increased overlap with powerful owls

The current diet of the sooty owl (Tyto tenebricosa) was determined by analysing freshly regurgitated pellets collected beneath their roosting sites in East Gippsland, Victoria. Comparisons were then made with: (i) prehistoric and historic diet from bone deposits found in cave roosts, and (ii) diet of a sympatric owl species, the powerful owl (Ninox strenua). Sooty owls consumed a large array of terrestrial mammal species before European settlement, but only three terrestrial species were detected in their current diet, a reduction of at least eight species since European settlement. To compensate, sooty owls have increased their consumption of arboreal prey from 55% to 81% of their diet. Arboreal species are also a major component of the powerful owl diet and this prey shift by sooty owls has increased dietary overlap between these two species. Predation by foxes (Vulpes vulpes) and other feral species is likely to have reduced the amount of terrestrial prey available to sooty owls since European settlement. Investigation of changes in the diet of sooty owls may offer a unique monitoring system for evaluating the ability of fox-control strategies to influence increases in numbers of critical-weight-range mammals.

Strategies which aim to positively impact on weight, physical activity, diet and sedentary behaviours in children from zero to five years. A systematic review of the literature

Preventing the development of obesity in children is an international health priority. To assess the effectiveness of interventions designed to prevent obesity, promote healthy eating and/or physical activity and/or to reduce sedentary behaviours in 0–5-year-old children, a systematic review of the literature was performed. Literature searches were limited to articles published between January 1995 and June 2006, printed in English and sampling children aged 0–5-years. Searches excluded literature concerned with breastfeeding, eating disorders, and interventions which were school-based or concerned with obesity treatment. Two reviewers independently extracted data and assessed study strengths and weaknesses. Nine included studies were grouped based on the settings in which they were delivered. Most studies involved multi-approach interventions, were conducted in the USA and varied in study designs and quality. All showed some level of effectiveness on at least one obesity-behaviour in young children. These studies support, at a range of levels, the premise that parents are receptive to and capable of some behavioural changes that may promote healthy weight in their young children. The small quantity of research heralds the need, particularly given the potential for early intervention to have long-lasting impacts on individual and population health, to build in a substantial way upon this evidence base.