The four food systems in developing countries and the challenges of modern supply chain inclusion for organic small-holders

To promote developmental objectives, such as growth, food security and improvement of the livelihoods of the rural poor, a greater understanding of the four food systems prevalent in the South is of great importance. Inclusion of small-holder farmers into the various food systems depends to a large extent on the capacity of the intermediaries and their ability to cope with both internal as well as external constraints while linking farmers to the agro-supply chains. The greater discrepancy between the intermediary’s own social and human capital resource base as well as the supporting resource environment, and the level of requirements demanded from agro-food systems; the greater constraints the stakeholders along the supply chain will encounter and the more difficult the inclusion of small-holder farmers will be

Inequity aversion and team incentives

We study how the optimal contract in team production is affected when employees are averse to inequity in the sense described by Fehr and Schmidt (1999). By designing a reward scheme that creates inequity of the desired equilibrium, the employer can induce employees to perform effort at a lower total wage cost than when they are not inequity averse. We also show that the optimal output choice might change when employees are inequity averse. Finally, we show that an employer can gain, and never lose, by designing a contract that accounts for inequity aversion, even if employees have standard preferences

Big hART at John Northcott Estate: Community, Health and the Arts

This paper considers the work of Big hART, a social impact of the Arts company, in their residency entitled Northcott Narratives over three and half years at John Northcott Estate, a public housing estate in Sydney. During this time Big hART used arts practice to engage tenants, strengthen their creative dispositions, and build relationships between tenants and a range of different communities. Northcott Narratives used a variety of multi-modal forms with tenants to inquire into, and then express ideas in relation to issues that confront them. These ideas are presented as social policy recommendations. The power and benefits of this form of arts practice along with the tensions and challenges are revealed. The paper adds to the developing discourse in relation to community cultural development

Dolphin-inspired target detection for sonar and radar

Gas bubbles in the ocean are produced by breaking waves, rainfall, methane seeps, exsolution, and a range of biological processes including decomposition, photosynthesis, respiration and digestion. However one biological process that produces particularly dense clouds of large bubbles, is bubble netting. This is practiced by several species of cetacean. Given their propensity to use acoustics, and the powerful acoustical attenuation and scattering that bubbles can cause, the relationship between sound and bubble nets is intriguing. It has been postulated that humpback whales produce ‘walls of sound’ at audio frequencies in their bubble nets, trapping prey. Dolphins, on the other hand, use high frequency acoustics for echolocation. This begs the question of whether, in producing bubble nets, they are generating echolocation clutter that potentially helps prey avoid detection (as their bubble nets would do with man-made sonar), or whether they have developed sonar techniques to detect prey within such bubble nets and distinguish it from clutter. Possible sonar schemes that could detect targets in bubble clouds are proposed, and shown to work both in the laboratory and at sea. Following this, similar radar schemes are proposed for the detection of buried explosives and catastrophe victims, and successful laboratory tests are undertaken

A computational approach for a fluid queue driven by a truncated birth-death process

In this paper, we consider a fluid queue driven by a truncated birth-death process with general birth and death rates. We find the equilibrium distribution of the content of the fluid buffer by computing the eigenvalues and eigenvectors of an associated real tridiagonal matrix. We provide efficient procedures which avoid numerical instability, to a greater extent, arising in a straightforward calculation of these quantities by standard procedures. In particular, we reduce the order of the matrix by one and show that this reduced matrix can be made symmetric and hence we could make use of the stable and efficient method of bisection to compute the eigenvalues. The effectiveness of these procedures is illustrated through tables and graphs. \u

Towards quantification of the water fooptprint of paper: a first estimate of its consumptive component

For a hardcopy of this article, printed in the Netherlands, an estimated 100 l of water have been used. Most of the water is required in the forestry stage, due to evapotranspiration (green and blue water). In addition, the water footprint during the industrial stage, as accounted for in this study, consists of evaporation from water obtained from ground water and surface water (blue water). In this study estimates are made of water requirements for producing paper using different types of wood and in different parts of the world. The water footprint of printing and writing paper is estimated to be between 300 and 2600 m3/t (~2-13 l for an A4 sheet). These estimates account for paper recovery rates in different countries. This study indicates that by using recovered paper for the production of paper the global average water footprint of paper is only 60% of what it would be if no recovered paper would be used at all. Further savings may be achieved by increasing the recovery percentages worldwide. In addition, the global water footprint of paper can be reduced by choosing production sites and wood types that are more water-efficient. The results of this study suggest that the use of recovered paper may be particularly effective in reducing water footprints. This study is a first step towards a better understanding of the significance of the water footprint of paper and the effect of using recovered paper

A High Reliability Asymptotic Approach for Packet Inter-Delivery Time Optimization in Cyber-Physical Systems

In cyber-physical systems such as automobiles, measurement data from sensor nodes should be delivered to other consumer nodes such as actuators in a regular fashion. But, in practical systems over unreliable media such as wireless, it is a significant challenge to guarantee small enough inter-delivery times for different clients with heterogeneous channel conditions and inter-delivery requirements. In this paper, we design scheduling policies aiming at satisfying the inter-delivery requirements of such clients. We formulate the problem as a risk-sensitive Markov Decision Process (MDP). Although the resulting problem involves an infinite state space, we first prove that there is an equivalent MDP involving only a finite number of states. Then we prove the existence of a stationary optimal policy and establish an algorithm to compute it in a finite number of steps. However, the bane of this and many similar problems is the resulting complexity, and, in an attempt to make fundamental progress, we further propose a new high reliability asymptotic approach. In essence, this approach considers the scenario when the channel failure probabilities for different clients are of the same order, and asymptotically approach zero. We thus proceed to determine the asymptotically optimal policy: in a two-client scenario, we show that the asymptotically optimal policy is a "modified least time-to-go" policy, which is intuitively appealing and easily implementable; in the general multi-client scenario, we are led to an SN policy, and we develop an algorithm of low computational complexity to obtain it. Simulation results show that the resulting policies perform well even in the pre-asymptotic regime with moderate failure probabilities

Numerical simulation of grain-size effects on creep crack growth by means of grain elements

The effect of grain size on creep crack growth is investigated by means of a numerical technique in which the actual crack growth process is simulated in a discrete manner by grain elements and grain boundary elements. The grain elements account for the creep deformation of individual grains, while grain boundary cavitation and sliding are accounted for by grain boundary elements between the grains. This grain-element technique allows for an independent study of multiple grain size effects: a (direct) size effect related to the specimen size/grain size ratio or an (indirect) effect related to the effect of grain size on nucleation rate and creep resistance. Preliminary numerical results are presented concerning the direct effect of grain size, which predict that the crack growth rate and brittleness increase with grain size.

The green and blue water footprint of paper products: methodological considerations and quantification

For a hardcopy of this report, printed in the Netherlands, an estimated 200 litres of water have been used. Water is required during different stages in the production process, from growing wood to processing pulp into the final consumer product. Most of the water is consumed in the forestry stage, where water consumption refers to the forest evapotranspiration. The water footprint during the manufacturing processes in the industrial stage consists of evaporation and contamination of ground- and surface water. In this report we assess water requirements for producing paper products using different types of wood and in different parts of the world. We quantify the combined green and blue water footprint of paper by considering the full supply chain; we do not include the grey water footprint in this study. The water footprint of printing and writing paper is estimated to be between 300 and 2600 m3/ton (2-13 litres for an A4 sheet). These figures account for the paper recovery rates as they currently are. The exact amount depends on the sort and origin of the paper used for printing. Without recovery, the global average water footprint of paper would be much larger; by using recovered paper an estimated 40% is saved globally. Further saving can be achieved by increasing the recovery percentages worldwide. For countries with a low recovered paper utilization rate a lot of room for reduction still remains. Some countries such as the Netherlands, Spain and Germany already use a lot of recovered paper. In addition, the global water footprint of paper can be reduced by choosing production sites and wood types that are more water-efficient. The findings presented in this report can be helpful in identifying the opportunities to reduce water footprints of paper consumption. This report also shows that the use of recovered paper may be very helpful in reducing water footprints

Internal field corrections in perpendicular columnar structured Alumite films

An investigation of the remanent and hysteretic properties of perpendicular media such as Alumite involves calculation of internal fields which requires the demagnetisation factor to be known. Demagnetisation effects have been calculated for Alumite, which is an ideal model material, by considering it as a hexagonal matrix of columns. This predicts that the demagnetising effects are less than that of a continuous film at saturation but increase as the magnetisation decreases