Robustness of animal production systems : concept and application to practical cases

A concept and method are developed and applied to improve robustness in animal production

Stable gonality is computable

Stable gonality is a multigraph parameter that measures the complexity of a graph. It is defined using maps to trees. Those maps, in some sense, divide the edges equally over the edges of the tree; stable gonality asks for the map with the minimum number of edges mapped to each edge of the tree. This parameter is related to treewidth, but unlike treewidth, it distinguishes multigraphs from their underlying simple graphs. Stable gonality is relevant for problems in number theory. In this paper, we show that deciding whether the stable gonality of a given graph is at most a given integer $k$ belongs to the class NP, and we give an algorithm that computes the stable gonality of a graph in $O((1.33n)^nm^m \text{poly}(n,m))$ time.Comment: 15 pages; v2 minor changes; v3 minor change

Integrated ecological hotspot identification of organic egg production

Ecological sustainability in agriculture is a concept that contains various environmental problems, which are caused by emission of compounds during different processes along the food chain. A precise ecological analysis of farming systems and food chains is needed in order to suggest and implement effective measures to improve sustainability. Life Cycle Assessment (LCA) assesses the environmental impact along the entire chain. In this research, LCA was used to locate environmental hotspots within the organic egg production chain and explore options that substantially improve ecological sustainability using sensitivity analysis. The environmental impact was expressed per kg of organic egg leaving the farm gate. Five environmental impact categories were included: 1) climate change i.e., emission of CO2, CH4 and N2O, 2) eutrophication i.e., emission of NH3, NOx, N2O and leaching of NO3 - and PO4 -, 3) acidification i.e., emission of NH3, NOx, and SOx, 4) fossil energy use i.e., oil, gas, uranium and coal and 5) land use. In case of a multifunctional process, economic allocation was used. We interviewed 20 out of 68 Dutch organic egg farmers to collect farm data for 2006. Data on transport, feed, rearing and hatching were gathered by the conduction of interviews with suppliers and from literature. The Life Cycle Inventories of electricity, natural gas, tap water, transport and cultivation originated from the Eco-Invent V2.0 dataset. A sensitivity analysis was executed for production parameters from the laying hen farm. To identify hotspots, the relative contribution of transportation, feed production, rearing and hatching and the laying hen farm, as well as the contribution of various compounds to each impact category was determined. We identified a chaincompound combination as a hotspot if it contributed to more than 40% of the total of the environmental impact category. Results showed four hotspots. First, 62% of climate change was caused by emission of N2O from soils during growing of feed. Second, 57% of acidification was caused by NH3 emission from the laying hen farm. Third, 47% of energy use was oil used for cultivation of feed and fourth, 95% of the land use was arable land required for feed production. We identified no hotspot for eutrophication, but feed production contributed most with 37% nitrogen leaching and 26% PO4 - leaching. From the sensitivity analysis it appeared that the most sensitive parameters on an organic laying hen farm are the number of produced eggs, the amount of feed consumed and the housing system. An increase in average egg production from 276 with a SD of 39 eggs per laying hen reduced climate change with 13%, acidification with 15%, eutrophication with 13%, energy use with 12% and land use with 12%. A reduction in average annual feed consumption from 42.9 kg with the SD of 7.2 kg per laying hen reduced climate change with 14%, acidification with 17%, eutrophication with 15%, energy use with 14% and land use with 13%. A shift from deep litter housing to an aviary housing with manure drying reduced climate change with 11%, acidification with 53%, eutrophication with 18% and had no effect on land use. The effect on energy use is still being assessed. We conclude that feed conversion and housing are effective ecological optimization options for organic laying hen farmers. However ecological sound feed production also needs attention

Potential of LCA for designing technological innovations – the case of organic eggs

Ecological sustainability in agriculture is a concept that contains various environmental problems, which are caused by emission of pollutants and unsustainable use of limited resources, during different processes along the food chain. Technological innovations may help to improve ecological sustainability of food products. Preceding to the development of ecological sustainable technological innovations three questions need to be answered; 1) how ecological sustainable is the current production process, 2) which processes in the chain causes the highest ecological impact and 3) which production parameters significantly affect the ecological impact of these processes? The aim of this research is to demonstrate Life Cycle Assessment to the designers of technological innovations Life Cycle Assessment as a method to answer these questions, by means of a case study of the organic egg. In this study the LCA of organic eggs was calculated and compared to equivalent egg products. Ecological hotspots within the production chain were identified and the effectiveness of production parameters from the laying hen farm were identified on the LCA using sensitivity analysis. This LCA case study showed that organic eggs score worse than equivalent eggs on acidification, eutrophication and land use. Technological innovators should focus on ammonia emission from the laying hen farm to reduce the impact of acidification. Another focus should be nitrate leaching during concentrate production to reduce eutrophication. Innovative organic laying hen farmers may focus on a high feed conversion to improve the LCA of organic eggs in a broader sense. A shift from single tiered housing of laying hens to multi tiered housing with manure drying on manure belts, can reduce acidification 53% and eutrophication with 18%, almost enough to level out the 60% higher acidification and the 25% higher eutrophication of organic eggs compared to equivalent egg products

On rainbow-free colourings of uniform hypergraphs

We study rainbow-free colourings of $k$-uniform hypergraphs; that is, colourings that use $k$ colours but with the property that no hyperedge attains all colours. We show that $p^*=(k-1)(\ln n)/n$ is the threshold function for the existence of a rainbow-free colouring in a random $k$-uniform hypergraph

Error Correction in Automatic Speech Recognition

This disclosure describes techniques to correct errors in automatic speech recognition, e.g., as performed to recognize spoken queries from a user to a virtual assistant or other application. A machine learning model detects potentially misrecognized n-grams within transcribed text which are then underlined in a user interface. A user can tap on the underlined n-gram, or another portion of the transcribed text to activate a dropdown menu that presents alternatives to the transcribed text. The alternatives can be based on speech hypothesis scores. To correct the error in transcribed text, the user picks an alternative from the dropdown menu, or, in the absence of a suitable alternative, types in the correction. With user permission, the error and corresponding correction are used as training data to improve model performance

Airborne microorganisms and dust from livestock houses

The objective of this study was to evaluate the efficiencies and suitability of samplers for airborne microorganisms and dust, which could be used in practical livestock houses. Two studies were performed: 1) Testing impaction and cyclone pre-separators for dust sampling in livestock houses; 2) Determining sampling efficiencies of four bioaerosol samplers for bacteria and virus. Study 1. The overloading problem of the EU reference impaction pre-separator (IPS) was tested in layer houses and compared with cyclone pre-separators (CPS) for sampling PM10 and PM2.5. Study 2. Physical and biological efficiencies of Andersen 6-stage impactor, all glass impinger (AGI-30), high air flow rate sampler OMNI-3000, and MD8 with gelatin filter were investigated for collecting aerosolized bacteria, Enterococcus faecalis, Escherichia coli, Campylobacter jejuni and Mycoplasma synoviae and live Gumboro vaccine virus. A tracer (uranine) was used to determine physical efficiencies and bioaerosol deposition. The study was done in a HEPA isolator (volume: 1.3 m3). The results show the PM10 IPS did not become overloaded in 24 h measurements in layer houses, whereas PM2.5 IPS became overloaded within 1 h. CPS did not become overloaded during 48 h sampling of both dust fractions. The OMNI-3000 (62%) had lower physical efficiency than the MD8, while the other samplers had similar efficiencies as MD8. All the bioaerosol samplers had high biological efficiencies for all four bacterial species, except for C. jejuni (1%) when measured with the OMNI-3000 and for E. coli (38%) and C. jejuni (2%) when measured with the MD8. The biological efficiencies of the Andersen impactor (61%), the AGI-30 (90%) and the MD8 (163%) were not significantly different from 100% for collecting the aerosolized virus. However, the biological efficiency (23%) of the OMNI-3000 was significantly lower than 100%