Neural network control of a simple mobile robot

In recent years researchers in the Department of Cybernetics have been developing simple mobile robots capable of exploring their environment on the basis of the information obtained from a few simple sensors. These robots are used as the test bed for exploring various behaviours of single and multiple organisms: the work is inspired by considerations of natural systems. In this paper we concentrate on that part of the work which involves neural networks and related techniques. These neural networks are used both to process the sensor information and to develop the strategy used to control the robot. Here the robots, their sensors, and the neural networks used and all described. 1.

Local management and landscape drivers of pollination and biological control services in a Kenyan agro-ecosystem

Arthropods that have a direct impact on crop production (i.e. pests, natural enemies and pollinators) can be influenced by both local farm management and the context within which the fields occur in the wider landscape. However, the contributions and spatial scales at which these drivers operate and interact are not fully understood, particularly in the developing world. The impact of both local management and landscape context on insect pollinators and natural enemy communities and on their capacity to deliver related ecosystem services to an economically important tropical crop, pigeonpea was investigated. The study was conducted in nine paired farms across a gradient of increasing distance to semi-native vegetation in Kibwezi, Kenya. Results show that proximity of fields to semi-native habitats negatively affected pollinator and chewing insect abundance. Within fields, pesticide use was a key negative predictor of pollinator, pest and foliar active predator abundance. On the contrary, fertilizer application significantly enhanced pollinator and both chewing and sucking insect pest abundance. At a 1 km spatial scale of fields, there were significant negative effects of the number of semi-native habitat patches within fields dominated by mass flowering pigeonpea on pollinators abundance. For service provision, a significant decline in fruit set when insects were excluded from flowers was recorded. This study reveals the interconnections of pollinators, predators and pests with pigeonpea crop. For sustainable yields and to conserve high densities of both pollinators and predators of pests within pigeonpea landscapes, it is crucial to target the adoption of less disruptive farm management practices such as reducing pesticide and fertilizer inputs.

Predicting natural ventilation in a two-zone building driven by combined forces.

Natural ventilation relies on less controllable natural forces so that it needs more artificial control, and thus its prediction, design and analysis become more important. This paper presents both theoretical and numerical simulations for predicting the natural ventilation flow in a two-zone building with multiple openings which is subjected to the combined natural forces. To our knowledge, this is the first analytical solutions obtained so far for a building with more than one zones and in each zone with possibly more than 2 openings. The analytical solution offers a possibility for validating a multi-zone airflow program. A computer program MIX is employed to conduct the numerical simulation. Good agreement is achieved. Different airflow modes are identified and some design recommendations are also provided.

Contested institutions? Traditional leaders and land access and control in communal areas of Eastern Cape Province, South Africa

The South African government has endeavoured to strengthen property rights in communal areas and develop civil society institutions for community-led development and natural resource management. However, the effectiveness of this remains unclear as the emergence and operation of civil society institutions in these areas is potentially constrained by the persistence of traditional authorities. Focusing on the former Transkei region of Eastern Cape Province, three case study communities are used examine the extent to which local institutions overlap in issues of land access and control. Within these communities, traditional leaders (chiefs and headmen) continue to exercise complete and sole authority over land allocation and use this to entrench their own positions. However, in the absence of effective state support, traditional authorities have only limited power over how land is used and in enforcing land rights, particularly over communal resources such as rangeland. This diminishes their local legitimacy and encourages some groups to contest their authority by cutting fences, ignoring collective grazing decisions and refusing to pay ‘fees’ levied on them. They are encouraged in such activities by the presence of democratically elected local civil society institutions such as ward councillors and farmers’ organisations, which have broad appeal and are increasingly responsible for much of the agrarian development that takes place, despite having no direct mandate over land. Where it occurs at all, interaction between these different institutions is generally restricted to approval being required from traditional leaders for land allocated to development projects. On this basis it is argued that a more radical approach to land reform in communal areas is required, which transfers all powers over land to elected and accountable local institutions and integrates land allocation, land management and agrarian development more effectively.

Maximising umami taste in meat using natural ingredients: effects on chemistry, sensory perception and hedonic liking in young and old consumers

BACKGROUND: Umami taste in foods is elicited predominantly by the presence of glutamic acid and 5’-ribonucleotides, which act synergistically. This study aimed to use natural ingredients to maximise umami taste of a meat formulation and determine effects on liking of older consumers. METHODS: Cooked meat products with added natural ingredients (yeast extract, mycoscent, shiitake extract, tomato puree, soy sauce and soy bean paste) or monosodium glutamate (MSG) were prepared and compared to a control sample analytically (umami compounds), sensorially (sensory profile) and hedonically (liking by younger and older volunteers). Taste detection thresholds of sodium chloride and MSG of volunteers were collected. RESULTS: Four of the seven cooked meat products developed had a significantly higher content of umami-contributing compounds compared to the control. All products, except those containing MSG or tomato puree, were scored (by trained sensory panel) perceptually significantly higher in umami and / or salty taste compared to the control. Consumer tests showed a correlation of liking by the older cohort with perceived saltiness (ρ=0.76). CONCLUSION: The addition of natural umami-containing ingredients during the cooking of meat can provide enhanced umami and salty taste characteristics, this can lead to increased liking by some consumers, particularly those with raised taste detection thresholds.

Comparison of pollinators and natural enemies: a meta-analysis of landscape and local effects on abundance and richness in crops

To manage agroecosystems for multiple ecosystem services, we need to know whether the management of one service has positive, negative, or no effects on other services. We do not yet have data on the interactions between pollination and pest-control services. However, we do have data on the distributions of pollinators and natural enemies in agroecosystems. Therefore, we compared these two groups of ecosystem service providers, to see if the management of farms and agricultural landscapes might have similar effects on the abundance and richness of both. In a meta-analysis, we compared 46 studies that sampled bees, predatory beetles, parasitic wasps, and spiders in fields, orchards, or vineyards of food crops. These studies used the proximity or proportion of non-crop or natural habitats in the landscapes surrounding these crops (a measure of landscape complexity), or the proximity or diversity of non-crop plants in the margins of these crops (a measure of local complexity), to explain the abundance or richness of these beneficial arthropods. Compositional complexity at both landscape and local scales had positive effects on both pollinators and natural enemies, but different effects on different taxa. Effects on bees and spiders were significantly positive, but effects on parasitoids and predatory beetles (mostly Carabidae and Staphylinidae) were inconclusive. Landscape complexity had significantly stronger effects on bees than it did on predatory beetles and significantly stronger effects in non-woody rather than in woody crops. Effects on richness were significantly stronger than effects on abundance, but possibly only for spiders. This abundance-richness difference might be caused by differences between generalists and specialists, or between arthropods that depend on non-crop habitats (ecotone species and dispersers) and those that do not (cultural species). We call this the ‘specialist-generalist’ or ‘cultural difference’ mechanism. If complexity has stronger effects on richness than abundance, it might have stronger effects on the stability than the magnitude of these arthropod-mediated ecosystem services. We conclude that some pollinators and natural enemies seem to have compatible responses to complexity, and it might be possible to manage agroecosystems for the benefit of both. However, too few studies have compared the two, and so we cannot yet conclude that there are no negative interactions between pollinators and natural enemies, and no trade-offs between pollination and pest-control services. Therefore, we suggest a framework for future research to bridge these gaps in our knowledge.

Cereal aphids and their natural enemies: responses to landscape composition and agri-environment schemes

There are potential conflicts between food security, biodiversity conservation and ecosystem services. Currently, there are still gaps in our understanding on the links between land use, biodiversity and ecosystem services; all have implications for sustainable agriculture. To improve food productivity in an ecologically friendly manner we should consider adapting current pest control techniques from being reliant on chemical means towards a more integrated approach. However, to do this, farmers and land owners require more information in order to make informed decisions. This brief review explores field level and landscape scale impacts on aphid control by their natural enemies. This will be done by exploring the effects of local field margin flower strips and two key landscape scale factors, winter wheat and lowland calcareous grasslands on aphids and their natural enemies. Research questions which need answering are discussed.