2,768 research outputs found
Economics of boar taint prevention without surgical castration in the pork chain
An economic analyses of boar taint prevention without surgical castration is lacking. This paper explores currently feasible alternatives to surgical castration along the pork chain. The considered alternatives include genetic selection (pig breeding stage); altering management strategies (pig growing stage); slaughter at younger age and lower weight (slaughtering stage). Control measures relevant to these alternatives were designed and examined, using costeffectiveness and cost-benefit analysis. Results show that the option of single-sex raising of entire males is more cost-effective compared to the mixed-sex option. The breeding programs combining selection on boar taint and economics are more cost-effective than programs focusing on boar taint only, and also much more cost-effective than slaughtering at a younger age and lower weigh
A Mathematical programming Model for Small Scale Family Farms in South Eastern South Dakota
Many farm operators are anxious to use the very latest technological tools in forward planning their farming operations. Among those tools are the computer and mathematical programming models. Small scale family farmers in southeastern South Dakota are as much in need of such technology as any businessman, industrialist, or large farm operator. However, the technical expertise necessary for developing and using a mathematical model has placed a limitation on its practical application. This publication presents a model for small scale family farm operations in southeastern South Dakota along with data input-output procedures that may be used by any person not specially trained in linear programming
Livestock transportation: a model for ex-ante policy analysis
The protection of live animals during transport in the EU is currently regulated under the Council Regulation No. 1/2005. The current legal regime is strongly criticized by the European society. To reform the existing regulation, policy makers need insights into the impact of possible transport restrictions for live animals. In this work, we propose a mathematical programming model to assess the potential impact of a policy reform involving limitations of travelling times and space allowances. This model is implemented for the years 2002 and 2013. A sensitivity analysis is performed on variations of fuel prices and cost of meat transpor
Normen voor huisvesting en arbeid voor de biologische varkenshouderij 2008
De berekeningen van de standaardstal en arbeidsnorm is bedoeld om een representatieve inschatting te geven ten behoeve van de bepaling van huisvestings- en arbeidskosten voor op continuïteit gerichte biologisch bedrijven. Deze analyse is uitgevoerd door LEI en ASG (Wageningen UR) in het kader van het Cluster Biologische Landbouw
Inference of the genetic network regulating lateral root initiation in Arabidopsis thaliana
Regulation of gene expression is crucial for organism growth, and it is one of the challenges in Systems Biology to reconstruct the underlying regulatory biological networks from transcriptomic data. The formation of lateral roots in Arabidopsis thaliana is stimulated by a cascade of regulators of which only the interactions of its initial elements have been identified. Using simulated gene expression data with known network topology, we compare the performance of inference algorithms, based on different approaches, for which ready-to-use software is available. We show that their performance improves with the network size and the inclusion of mutants. We then analyse two sets of genes, whose activity is likely to be relevant to lateral root initiation in Arabidopsis, by integrating sequence analysis with the intersection of the results of the best performing methods on time series and mutants to infer their regulatory network. The methods applied capture known interactions between genes that are candidate regulators at early stages of development. The network inferred from genes significantly expressed during lateral root formation exhibits distinct scale-free, small world and hierarchical properties and the nodes with a high out-degree may warrant further investigation
Design and fabrication of a low cost implantable bladder pressure monitor
In the frame of the Flemish Community funded project Bioflex we developed and fabricated an implant for short term (< 7 days) bladder pressure monitoring, and diagnosis of incontinence. This implant is soft and flexible to prevent damaging the bladder's inner wall. It contains a standard flexible electronic circuit connected to a battery, which are embedded in surface treated silicone to enhance the biocompatibility and prevent salt deposition. This article describes the fabrication of the pill and the results of preliminary cytotoxicity tests. The electronic design and its tests, implantation and the result of the in-vivo experimentation will be presented in other articles
Module networks revisited: computational assessment and prioritization of model predictions
The solution of high-dimensional inference and prediction problems in
computational biology is almost always a compromise between mathematical theory
and practical constraints such as limited computational resources. As time
progresses, computational power increases but well-established inference
methods often remain locked in their initial suboptimal solution. We revisit
the approach of Segal et al. (2003) to infer regulatory modules and their
condition-specific regulators from gene expression data. In contrast to their
direct optimization-based solution we use a more representative centroid-like
solution extracted from an ensemble of possible statistical models to explain
the data. The ensemble method automatically selects a subset of most
informative genes and builds a quantitatively better model for them. Genes
which cluster together in the majority of models produce functionally more
coherent modules. Regulators which are consistently assigned to a module are
more often supported by literature, but a single model always contains many
regulator assignments not supported by the ensemble. Reliably detecting
condition-specific or combinatorial regulation is particularly hard in a single
optimum but can be achieved using ensemble averaging.Comment: 8 pages REVTeX, 6 figure
Conservation of Nonsense-Mediated mRNA Decay Complex Components Throughout Eukaryotic Evolution
Nonsense-mediated mRNA decay (NMD) is an essential eukaryotic process regulating transcript quality and abundance, and is involved in diverse processes including brain development and plant defenses. Although some of the NMD machinery is conserved between kingdoms, little is known about its evolution. Phosphorylation of the core NMD component UPF1 is critical for NMD and is regulated in mammals by the SURF complex (UPF1, SMG1 kinase, SMG8, SMG9 and eukaryotic release factors). However, since SMG1 is reportedly missing from the genomes of fungi and the plant Arabidopsis thaliana, it remains unclear how UPF1 is activated outside the metazoa. We used comparative genomics to determine the conservation of the NMD pathway across eukaryotic evolution. We show that SURF components are present in all major eukaryotic lineages, including fungi, suggesting that in addition to UPF1 and SMG1, SMG8 and SMG9 also existed in the last eukaryotic common ancestor, 1.8 billion years ago. However, despite the ancient origins of the SURF complex, we also found that SURF factors have been independently lost across the Eukarya, pointing to genetic buffering within the essential NMD pathway. We infer an ancient role for SURF in regulating UPF1, and the intriguing possibility of undiscovered NMD regulatory pathways
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