28 research outputs found

    Self-stabilizing TDMA Algorithms for Wireless Ad-hoc Networks without External Reference

    Full text link
    Time division multiple access (TDMA) is a method for sharing communication media. In wireless communications, TDMA algorithms often divide the radio time into timeslots of uniform size, ξ\xi, and then combine them into frames of uniform size, τ\tau. We consider TDMA algorithms that allocate at least one timeslot in every frame to every node. Given a maximal node degree, δ\delta, and no access to external references for collision detection, time or position, we consider the problem of collision-free self-stabilizing TDMA algorithms that use constant frame size. We demonstrate that this problem has no solution when the frame size is τ<max{2δ,χ2}\tau < \max\{2\delta,\chi_2\}, where χ2\chi_2 is the chromatic number for distance-22 vertex coloring. As a complement to this lower bound, we focus on proving the existence of collision-free self-stabilizing TDMA algorithms that use constant frame size of τ\tau. We consider basic settings (no hardware support for collision detection and no prior clock synchronization), and the collision of concurrent transmissions from transmitters that are at most two hops apart. In the context of self-stabilizing systems that have no external reference, we are the first to study this problem (to the best of our knowledge), and use simulations to show convergence even with computation time uncertainties

    Confinement of sows for different periods during lactation: effects on behaviour and lesions of sows and performance of piglets.

    Get PDF
    Alternatives to farrowing crates with continuous confinement of the sow are urgently needed because the animal welfare is negatively impacted. Given the increase of herd sizes, practical experience with loose-housing is needed to force the implementation of these systems in the field. Next to aspects of labour efficiency, detrimental piglet mortality rates that may occur during the first days postpartum (pp) is a major criticism. Therefore, loose-housing after a crating period limited to the first days pp might be a feasible alternative to improve welfare under intensive production conditions. The aim was to investigate the effect of crating sows during lactation for different periods on their behaviour and integument alterations and on piglets' performance. Gilts from a commercial herd were observed from 5 to 26 days pp and housed in farrowing crates (1.85×2.50 m) that could be altered between confinement crates and loose-housing pens. Animals were divided into three groups, that were either crated continuously from birth until weaning (Group A, n=55), until 14 days pp (Group B; n=54) or 7 days pp (Group C, n=59). The behaviour of six randomly selected gilts per group was video recorded from 5 to 26 days pp and analysed by time sampling technique. Lesions on the legs, shoulder and lumbar vertebra were scored on days 7, 14 and 25 pp. Piglets were weighed weekly, causes of losses recorded and weight losses of gilts measured. Not different between groups (P>0.05), animals spent 72 to 76% lying laterally, 14 to 17% lying in abdominal or semi-abdominal position, 9 to 10% standing and 1 to 3% sitting. B-sows were lying longer in week 3 and 4 of lactation compared to A- and C-sows (P0.05), whereas almost 90% of the losses occurred in the first week pp. In conclusion, loose-housing of lactating gilts after a reduced postnatal crating period of 7 days affected neither the activity level of the gilts and lesions on the integument nor pre-weaning mortality. Therefore, it is recommended to allow sows to move around to some extent during the later lactation period

    Structural differences among pig genomes illustrate genetic uniqueness of breeds

    Get PDF
    The availability of high-throughput whole-genome sequencing (WGS) data illustrating differences among different pig breed genomes opened a new area of genomic research focused on variation caused by single nucleotide polymorphisms (SNP), small scale variation and structural variants which may all contribute to phenotypic variation among pig breeds. In our study (performed within TREASURE project) we re-analysed WGS-based data sets from more than 20 breeds, including commercial and local breeds as well as some wild boar genomes, deposited in publicly available databases. This bioinformatics tool enables discovery of new SNPs, estimation of allele frequencies (genotyping by sequencing) at candidate loci and identification of structural variation in a wide range of pig breeds. The analysis underlined the relevance of structural differences at KIT and MC1R locus involved in colour pattern formation, as well as LEPR locus associated with fatness, fatty acid metabolism and intramuscular fat composition. This approach allows discovery of important genomic differences between commercial breeds and local breeds which are analysed in the frame of the TREASURE project. Extensive mining of publicly available genomic data can together with the newly generated genomic information from local breeds, significantly contribute to the detailed characterisation of animal genetic resources present in local pig breeds. Funded by European Union’s H2020 RIA program (grant agreement No. 634476)

    Environmental and land use consequences of replacing milk and beef with plant-based alternatives

    Get PDF
    The consumption of meat and dairy products raise enormous environmental concerns. Circa 80% of global greenhouse gas emissions (GHG) from the livestock industry originate from beef, milk and pork production. Changing the production and consumption of meat and dairy products is considered to offer an important contribution to achieving the Paris Agreement climate targets (UNFCCC, 2015), and could reduce the import of soybean meal to Europe from countries where it is linked with deforestation. However, individual diet substitutions may have indirect and unintended environmental consequences across interlinked livestock systems – hence a wider assessment of impacts of consumption changes is required using consequential life cycle assessment (LCA). In this study, we investigated the environmental consequences of two independent yet interconnected diet choices in a German context: (i) replacing dairy milk with soy milk, and; (ii) replacing beef meatballs with pea protein balls. We related commodity demand to detailed agricultural rotations and land use changes via farm scale economic modelling coupled with consequential LCA. The substitution of beef meatballs with pea-derived protein balls can result in GHG savings of 2.4 kg CO2e per 100 g serving, and up to 7.3 kg CO2e per 100 g serving if spared land is afforested. Environmental problems related to nutrient leakage such as acidification and eutrophication are also mitigated. Meanwhile, unless accompanied by dramatic reductions in beef consumption, the substitution of cow milk with soy-based milk does not lead to significant GHG mitigation owing to the displacement of dairy-beef production to less efficient suckler-beef systems. Nonetheless, land sparing by cow milk substitution could support overall GHG mitigation if combined with afforestation. This study confirms that legumes can play an important role in diet transitions towards climate neutrality, especially via substitution of meat (as opposed to dairy) products

    Encuesta de datos demográficos y fenotípicos de razas locales de cerdos del proyecto TREASURE

    Get PDF
    The paper reports the results of a survey on the demographic and phenotypic characterization of 20 European local pig breeds involved in the H2020 TREASURE project including information on: demographic parameters, main morphological features, reproductive information, additional information collected at herd-level (i.e. temperament, holding, mating practices), origins and development of the breeds. Almost all the breeds (18 out of 20) possess a herd book even if the starting year is highly variable (from 1980 to 2006). Number of breeding females ranged from 24 (Moravka) to over 200,000 heads (Ibérico). Male/female ratio varied greatly with the highest values for the Italian breeds probably due to the different policy of animal recording. Almost all the breeds undergo a conservation program whereas really few are interested by other conservation techniques and for less than five breeds data related to effective number and inbreeding coefficient are easily available. Average values for teat number, litter size and weaned piglets are 12, 8 and 6 respectively with a great potential for their improvement. The depicted scenario is highly diversified and the data collected represent the starting point for the achievement of a collective trademark under the umbrella of the TREASURE project

    Potential Use of Near-Infrared Spectroscopy to Predict Fatty Acid Profile of Meat from Different European Autochthonous Pig Breeds

    Get PDF
    Autochthonous pig breeds provide products of differentiated quality, among which quality control is difficult to perform and insufficient for current market requirements. The present research evaluates the predictive ability of near‐infrared (NIR) spectroscopy, combined with chemometric methods as a rapid and affordable tool to assure traceability and quality control. Thus, NIR technology was assessed for intact and minced muscle Longissimus thoracis et lumborum samples collected from 12 European autochthonous pig breeds for the quantification of lipid content and fatty acid composition. Different tests were performed using different numbers of samples for calibration and validation. The best predictive ability was found using minced presentation and set with 80% of the samples for the calibration and the remaining 20% for the external validation test for the following traits: lipid content and saturated and polyunsaturated fatty acids, which attained both the highest determination coefficients (0.89, 0.61, and 0.65, respectively) and the lowest root mean square errors in external validation (0.62, 1.82, and 1.36, respectively). Lower predictive ability was observed for intact muscles. These results could contribute to improve the management of autochthonous breeds and to ensure quality of their products by traditional meat industry chains

    Prediction of fatty acid composition in intact and minced fat of European autochthonous pigs breeds by near infrared spectroscopy

    Get PDF
    The fatty acids profile has been playing a decisive role in recent years, thanks to technological, sensory and health demands from producers and consumers. The application of NIRS technique on fat tissues, could lead to more efficient, practical, and economical in the quality control. The study aim was to assess the accuracy of Fourier Transformed Near Infrared Spectroscopy technique to determine fatty acids composition in fat of 12 European local pig breeds. A total of 439 spectra of backfat were collected both in intact and minced tissue and then were analyzed using gas chromatographic analysis. Predictive equations were developed using the 80% of samples for the calibration, followed by full cross validation, and the remaining 20% for the external validation test. NIRS analysis of minced samples allowed a better response for fatty acid families, n6 PUFA, it is promising both for n3 PUFA quantification and for the screening (high, low value) of the major fatty acids. Intact fat prediction, although with a lower predictive ability, seems suitable for PUFA and n6 PUFA while for other families allows only a discrimination between high and low values.IRTA acknowledge the Consolidated Research Group (2021 SGR 00461) and CERCA Program to partially support this work
    corecore