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- Bauer, Pavol, et al.
(författare)
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Fast event-based epidemiological simulations on national scales
- 2016
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Ingår i: The international journal of high performance computing applications. - : SAGE Publications. - 1094-3420 .- 1741-2846. ; 30, s. 438-453
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Tidskriftsartikel (refereegranskat)abstract
- We present a computational modeling framework for data-driven simulations and analysis of infectious disease spread in large populations. For the purpose of efficient simulations, we devise a parallel solution algorithm targeting multi-socket shared-memory architectures. The model integrates infectious dynamics as continuous-time Markov chains and available data such as animal movements or aging are incorporated as externally defined events. To bring out parallelism and accelerate the computations, we decompose the spatial domain and optimize cross-boundary communication using dependency-aware task scheduling. Using registered livestock data at a high spatiotemporal resolution, we demonstrate that our approach not only is resilient to varying model configurations but also scales on all physical cores at realistic workloads. Finally, we show that these very features enable the solution of inverse problems on national scales.
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| 7. |
- Widgren, Stefan, et al.
(författare)
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Spatio-temporal modelling of verotoxigenic Escherichia coli O157 in cattle in Sweden: exploring options for control
- 2018
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Ingår i: Veterinary Research. - : Springer Science and Business Media LLC. - 0928-4249 .- 1297-9716. ; 49
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Tidskriftsartikel (refereegranskat)abstract
- A spatial data-driven stochastic model was developed to explore the spread of verotoxigenic Escherichia coli O157 (VTEC O157) by livestock movements and local transmission among neighbouring holdings in the complete Swedish cattle population. Livestock data were incorporated to model the time-varying contact network between holdings and population demographics. Furthermore, meteorological data with the average temperature at the geographical location of each holding was used to incorporate season. The model was fitted against observed data and extensive numerical experiments were conducted to investigate the model's response to control strategies aimed at reducing shedding and susceptibility, as well as interventions informed by network measures. The results showed that including local spread and season improved agreement with prevalence studies. Also, control strategies aimed at reducing the average shedding rate were more efficient in reducing the VTEC O157 prevalence than strategies based on network measures. The methodology presented in this study could provide a basis for developing disease surveillance on regional and national scales, where observed data are combined with readily available high-resolution data in simulations to get an overview of potential disease spread in unobserved regions.
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| 8. |
- Andersson, Emma, et al.
(författare)
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Impact of first parity litter size on sow stayability and lifetime production
- 2015
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- To increase production level increase of number of piglets born per litter has been one of the main breeding goals during the last decades. The negative welfare consequences on piglets being born in a large litter are well known while the welfare impacts on sows that produce large litters are more uncertain. The aim of this study was to investigate the effect of first parity litter size on sow stayability and lifetime production. Sows having a small (<12 piglets total born; SL) or medium (12-14 piglets total born; ML) first parity litter size had significantly (p <0.001) more litters before end of production than sows having a large (>14 piglets total born; LL) first parity litter size. Sows with LL was significant (p<0.001) less likely to have a second litter than sows with SL and ML. Sows with SL and ML had the highest lifetime production of weaned piglets. The results of this study indicate that it is important take first parity litter size into account when assessing sow welfare and profitability in commercial piglet producing herds. Having a SL or ML was found to have a positive effect on sow stayability and lifetime production.
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| 10. |
- Andersson, Emma, et al.
(författare)
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Impact of litter size on sow stayability in Swedish commercial piglet producing herds
- 2016
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Ingår i: Acta Veterinaria Scandinavica. - : Springer Science and Business Media LLC. - 0044-605X .- 1751-0147. ; 58
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Tidskriftsartikel (refereegranskat)abstract
- Background: Sows' ability to produce an excessive amount of piglets has shaped modern piglet production and there has been a steady increase in litter size during the last decades. This development has caused some negative side-effects, such as an increase in the proportion of stillborn piglets, a decrease in the proportion of weaned piglets and a larger variation in quality of piglets. Swedish commercial piglet producing herds have, like other countries with high production levels, high piglet mortality and high annual removal rate of gilts and sow. These problems seem to have increased during the same period that litter sizes have increased. Therefore present study aim to investigate whether there is an association between litter sizes and sow stayability. Results: The probability to produce ≥4 litters during a lifetime was significantly lower for sows giving birth to ≤8, 15 and ≥17 piglets in total in their first parity litter compared to sows giving birth to 13 piglets. Except for the group of sows having a small (≤11 piglets born in total) first parity litter size in combination with a medium (12-14 piglets born in total) second parity litter size, all other groups were significantly associated with an impaired ability to stay ≥4 litters compared to sows having a medium both first and second parity litter size. There were differences in removal reason between sows having small, medium or large first parities litter sizes. Conclusions: Associations between litter sizes in low parities and sow stayability were found. Our results indicate that aiming for keeping sows giving birth to a medium-sized litter, with approximately 12-14 piglets born in total may improve sows stayability and decrease the risk of unplanned removal. This should be considered when planning breeding strategy and annual removal in Swedish commercial piglets producing herds.
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