Formal-informal economy linkages and unemployment in South Africa:

South Africa's high involuntary unemployment and small informal sector are attributed to an underperforming formal sector and barriers to entry in the informal sector. This paper examines the economywide linkages between the formal and informal economies while accounting for different types of informal activities. A multiregion empirically calibrated general equilibrium model is developed capturing both product and labor markets. Three policy options are considered. First, results indicate that trade liberalization reduces national employment. At the same time, it increases formal employment, hurts informal producers, and favors informal traders, who benefit from lower import prices. Past liberalization may, therefore, partly explain South Africa's small informal sector and its concentration among traders rather than producers. Second, wage subsidies on low-skilled formal workers increase national employment but hurt informal producers by heightening competition in domestic product markets. This suggests that it is insufficient to examine unemployment policies by focusing only on labor markets. Third, unconditional cash transfers stimulate demand for informally produced products, thereby raising informal employment without undermining formal producers. The transfer does, however, place a large fiscal burden on the state and is less effective at reducing national unemployment than a wage subsidy. Overall, these findings underline the importance of distinguishing between the formal and informal sector implications of socioeconomic policies.informal economy, involuntary unemployment, formal economy, labor markets, trade liberalization, national employment, Cash transfers, wage subsidy, Computable general equilibrium (CGE) modeling, Development strategies,

Associative memory in gene regulation networks

The pattern of gene expression in the phenotype of an organism is determined in part by the dynamical attractors of the organism’s gene regulation network. Changes to the connections in this network over evolutionary time alter the adult gene expression pattern and hence the fitness of the organism. However, the evolution of structure in gene expression networks (potentially reflecting past selective environments) and its affordances and limitations with respect to enhancing evolvability is poorly understood in general. In this paper we model the evolution of a gene regulation network in a controlled scenario. We show that selected changes to connections in the regulation network make the currently selected gene expression pattern more robust to environmental variation. Moreover, such changes to connections are necessarily ‘Hebbian’ – ‘genes that fire together wire together’ – i.e. genes whose expression is selected for in the same selective environments become co-regulated. Accordingly, in a manner formally equivalent to well-understood learning behaviour in artificial neural networks, a gene expression network will therefore develop a generalised associative memory of past selected phenotypes. This theoretical framework helps us to better understand the relationship between homeostasis and evolvability (i.e. selection to reduce variability facilitates structured variability), and shows that, in principle, a gene regulation network has the potential to develop ‘recall’ capabilities normally reserved for cognitive systems

Online platforms of public participation -- a deliberative democracy or a delusion?

Trust and confidence in democratic institutions is at an all-time low. At the same time, many of the complex issues faced by city administrators and politicians remain unresolved. To tackle these concerns, many argue that citizens should, through the use of digital platforms, have greater involvement in decision-making processes. This paper describes research into two such platforms, 'Decide Madrid' and 'Better Reykjavik'. Through the use of interviews, questionnaires, ethnographic observation, and analysis of platform data, the study will determine if these platforms provide greater participation or simply replicate what is already offered by numerous other digital tools. The findings so far suggest that to be successful platforms must take on a form of deliberative democracy, allowing for knowledge co-production and the emergence of collective intelligence. Based on this, we aim to identify key features of sustainable models of online participation.Comment: 8 page

Adaptation without natural selection

Document is itself an extended abstract

If you can't be with the one you love, love the one you're with: How individual habituation of agent interactions improves global utility

Simple distributed strategies that modify the behaviour of selfish individuals in a manner that enhances cooperation or global efficiency have proved difficult to identify. We consider a network of selfish agents who each optimise their individual utilities by coordinating (or anti-coordinating) with their neighbours, to maximise the pay-offs from randomly weighted pair-wise games. In general, agents will opt for the behaviour that is the best compromise (for them) of the many conflicting constraints created by their neighbours, but the attractors of the system as a whole will not maximise total utility. We then consider agents that act as 'creatures of habit' by increasing their preference to coordinate (anti-coordinate) with whichever neighbours they are coordinated (anti-coordinated) with at the present moment. These preferences change slowly while the system is repeatedly perturbed such that it settles to many different local attractors. We find that under these conditions, with each perturbation there is a progressively higher chance of the system settling to a configuration with high total utility. Eventually, only one attractor remains, and that attractor is very likely to maximise (or almost maximise) global utility. This counterintutitve result can be understood using theory from computational neuroscience; we show that this simple form of habituation is equivalent to Hebbian learning, and the improved optimisation of global utility that is observed results from wellknown generalisation capabilities of associative memory acting at the network scale. This causes the system of selfish agents, each acting individually but habitually, to collectively identify configurations that maximise total utility

A study of the effect of movement of outdoor pigs to a new site on Salmonella prevalence

Outdoor breeding of pigs in Great Britain constitutes a substantial proportion of the British pig industry, with at least 40% of the breeding herd kept outdoors. Outdoor production is viewed as more welfare friendly and forms a break between cereal crops. Outdoor pig production has a tendency for high Salmonella seroprevalence at slaughter, with evidence for a wide diversity of resident and transient infections on farm, often showing some overlap with local environmental and wildlife isolates. Outdoor pigs may be at increased risk of infection due to: the lack of a controlled environment that can be cleaned and disinfected between batches of pigs; less control over exposure of pigs to factors such as cold and heat stress; and increased exposure to Salmonella through difficulties in applying biosecurity for personnel and vehicles as well as increased contact with the environment and wildlife. Anecdotal information has shown that moving outdoor pigs to new land is usually followed by an improvement in herd health and productivity. It is believed that outdoor herds in the UK typically move site every 2-3 years. The aim of this longitudinal study was to investigate the effect on the occurrence of Salmonella of moving pigs to new land and the sustainability of any improvements over a one year period