97 research outputs found

    Play behaviour positively relates to weight gain, feeding behaviour and drinking behaviour in weaner pigs (Sus scrofa)

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    Engagement in play behaviour has been associated with the presence of positive affective states and, thus, proposed to be an indicator of positive animal welfare. However, the interpretation of play in animals remains challenging due to the complexity of motivating factors. Accordingly, we aimed to clarify whether Yorkshire × Landrace weaner pigs would engage more in play behaviour the more well-nourished they were by examining the effects of weight gain, feeding behaviour, and drinking behaviour on two types of play behaviour [locomotor-rotational play (LOC) and social play (SOC)]. In total, 24 litters [pigs/litter: (mean ± SD) 13 ± 2] raised under conventional husbandry conditions were included in this study. Each pig was manually weighed within 24 h of birth and on days − 7, 0, 1, 2 relative to the weaning day (day 0) at approximately 26 days of age. All behavioural measures were registered via video at individual level. Visits to feeder and drinker were registered from 07:00 h to 21:59 h on days − 1 and 1 using 2-min interval instantaneous sampling. The proportion of visits to each resource was calculated by dividing the number of scans visiting the resource by the total number of daily scans. The latencies to visit the feeder and drinker within the first 24 h post-weaning were continuously recorded. Both LOC and SOC were registered between 14:00 h and 22:00 h on days − 1, 1 and 2. Both before and after weaning, heavier pigs spent more time performing LOC. Before weaning, heavier pigs spent more time performing SOC. Proportion of visits to the feeder positively related to LOC after weaning. On the day before weaning, the proportion of visits to the drinker positively related to LOC. No clear relationships between the latency to feed and drink after weaning and play behaviour were found. Our study supports the hypothesis that motivation to play is higher when animals are in more stable conditions, e.g., well-nourished, and healthier than under suboptimal conditions. However, the fact that the nutritional measures did not similarly affect LOC and SOC suggests that these two types of play behaviour may be differently affected by the weaning context and questions whether they have the same underlying motivation. This study represents a step toward the validation of play as a positive animal welfare indicator

    SIDER : an R package for predicting trophic discrimination factors of consumers based on their ecology and phylogenetic relatedness

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    KH acknowledges support from the Marie Curie Research Grants Scheme, grant [749594] and Science Foundation Ireland awarded to Yvonne Buckley. TG acknowledges support from European Research Council under the European Union’s Seventh Framework Programme (FP/2007–2013)/ERC Grant Agreement number 311092 awarded to Martin D. Brazeau. AJ was funded by a research scholarship administered by the Fulbright Commission of Ireland and in conjunction with the Marine Institute of Ireland. SB & RI are funded by an ERC consolidators grant (STATEMIG: 310820). The data used to fit the regression models, along with the code itself is bundled within the R package and is available on GitHub https://github.com/healyke/SIDER, with the data also on Figshare https://figshare.com/articles/Dataset_for_the_SIDER_R_package/4737481. Data available from the Dryad Digital Repository: http://dx.doi.org/10.5061/dryad.c6035 (Healy et al. 2017).Stable isotope mixing models (SIMMs) are an important tool used to study species' trophic ecology. These models are dependent on, and sensitive to, the choice of trophic discrimination factors (TDF) representing the offset in stable isotope delta values between a consumer and their food source when they are at equilibrium. Ideally, controlled feeding trials should be conducted to determine the appropriate TDF for each consumer, tissue type, food source, and isotope combination used in a study. In reality however, this is often not feasible nor practical. In the absence of species-specific information, many researchers either default to an average TDF value for the major taxonomic group of their consumer, or they choose the nearest phylogenetic neighbour for which a TDF is available. Here, we present the SIDER package for R, which uses a phylogenetic regression model based on a compiled dataset to impute (estimate) a TDF of a consumer. We apply information on the tissue type and feeding ecology of the consumer, all of which are known to affect TDFs, using Bayesian inference. Presently, our approach can estimate TDFs for two commonly used isotopes (nitrogen and carbon), for species of mammals and birds with or without previous TDF information. The estimated posterior probability provides both a mean and variance, reflecting the uncertainty of the estimate, and can be subsequently used in the current suite of SIMM software. SIDER allows users to place a greater degree of confidence on their choice of TDF and its associated uncertainty, thereby leading to more robust predictions about trophic relationships in cases where study-specific data from feeding trials is unavailable. The underlying database can be updated readily to incorporate more stable isotope tracers, replicates and taxonomic groups to further increase the confidence in dietary estimates from stable isotope mixing models, as this information becomes available.PostprintPeer reviewe

    Quaternary vertebrate faunas from Sumba, Indonesia: implications for Wallacean biogeography and evolution

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    Historical patterns of diversity, biogeography and faunal turnover remain poorly understood for Wallacea, the biologically and geologically complex island region between the Asian and Australian continental shelves. A distinctive Quaternary vertebrate fauna containing the small-bodied hominin Homo floresiensis, pygmy Stegodon proboscideans, varanids and giant murids has been described from Flores, but Quaternary faunas are poorly known from most other Lesser Sunda Islands. We report the discovery of extensive new fossil vertebrate collections from Pleistocene and Holocene deposits on Sumba, a large Wallacean island situated less than 50 km south of Flores. A fossil assemblage recovered from a Pleistocene deposit at Lewapaku in the interior highlands of Sumba, which may be close to 1 million years old, contains a series of skeletal elements of a very small Stegodon referable to S. sumbaensis, a tooth attributable to Varanus komodoensis, and fragmentary remains of unidentified giant murids. Holocene cave deposits at Mahaniwa dated to approximately 2000–3500 BP yielded extensive material of two new genera of endemic large-bodied murids, as well as fossils of an extinct frugivorous varanid. This new baseline for reconstructing Wallacean faunal histories reveals that Sumba's Quaternary vertebrate fauna, although phylogenetically distinctive, was comparable in diversity and composition to the Quaternary fauna of Flores, suggesting that similar assemblages may have characterized Quaternary terrestrial ecosystems on many or all of the larger Lesser Sunda Islands

    Markovian Equilibrium in Infinite Horizon Economies with Incomplete Markets and Public Policy

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    We develop an isotone recursive approach to the problem of existence, computation, and characterization of nonsymmetric locally Lipschitz continuous (and, therefore, Clarke-differentiable) Markovian equilibrium for a class of infinite horizon multiagent competitive equilibrium models with capital, aggregate risk, public policy, externalities, one sector production, and incomplete markets. The class of models we consider is large, and examples have been studied extensively in the applied literature in public economics, macroeconomics, and financial economics. We provide sufficient conditions that distinguish between economies with isotone Lipschitizian Markov equilibrium decision processes (MEDPs) and those that have only locally Lipschitzian (but not necessarily isotone) MEDPs. As our fixed point operators are based upon order continuous and compact non-linear operators, we are able to provide sufficient conditions under which isotone iterative fixed point constructions converge to extremal MEDPs via successive approximation. We develop a first application of a new method for computing MEDPs in a system of Euler inequalities using isotone fixed point theory even when MEDPs are not necessarily isotone. The method is a special case of a more general mixed monotone recursive approach. We show MEDPs are unique only under very restrictive conditions. Finally, we prove monotone comparison theorems in Veinott's strong set order on the space of public policy parameters and distorted production functions

    Front Immunol

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    HIV-2 infection is characterized by low viremia and slow disease progression as compared to HIV-1 infection. Circulating CD14++CD16+ monocytes were found to accumulate and CD11c+ conventional dendritic cells (cDC) to be depleted in a Portuguese cohort of people living with HIV-2 (PLWHIV-2), compared to blood bank healthy donors (HD). We studied more precisely classical monocytes; CD16+ inflammatory (intermediate, non-classical and slan+ monocytes, known to accumulate during viremic HIV-1 infection); cDC1, important for cross-presentation, and cDC2, both depleted during HIV-1 infection. We analyzed by flow cytometry these PBMC subsets from Paris area residents: 29 asymptomatic, untreated PLWHIV-2 from the IMMUNOVIR-2 study, part of the ANRS-CO5 HIV-2 cohort: 19 long-term non-progressors (LTNP; infection ≥8 years, undetectable viral load, stable CD4 counts≥500/μL; 17 of West-African origin -WA), and 10 non-LTNP (P; progressive infection; 9 WA); and 30 age-and sex-matched controls: 16 blood bank HD with unknown geographical origin, and 10 HD of WA origin (GeoHD). We measured plasma bacterial translocation markers by ELISA. Non-classical monocyte counts were higher in GeoHD than in HD (54 vs. 32 cells/μL, p = 0.0002). Slan+ monocyte counts were twice as high in GeoHD than in HD (WA: 28 vs. 13 cells/μL, p = 0.0002). Thus cell counts were compared only between participants of WA origin. They were similar in LTNP, P and GeoHD, indicating that there were no HIV-2 related differences. cDC counts did not show major differences between the groups. Interestingly, inflammatory monocyte counts correlated with plasma sCD14 and LBP only in PLWHIV-2, especially LTNP, and not in GeoHD. In conclusion, in LTNP PLWHIV-2, inflammatory monocyte counts correlated with LBP or sCD14 plasma levels, indicating a potential innate immune response to subclinical bacterial translocation. As GeoHD had higher inflammatory monocyte counts than HD, our data also show that specific controls are important to refine innate immunity studies

    Influence of recess shape on the noise and gain performance of FET's in the millimeter wave range

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    The effect of the recess shape on the FET noise performance is investigated from a theoretical point of view. The noise modelling is based on quasi two dimensional calculation including non stationary transport. The degradation of the noise figure with the recess-to-gate and gate-to-recess distances is emphasized

    STRENGTH OF OPTICAL FIBRES UNDER COMBINED STRESSES AND AGING IN VARIOUS ENVIRONMENTS

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    Ce papier est un appercu des différents paramètres déterminant, du point de vue mécanique, des fibres optiques. A la lumière de la mécanique des cassures, des statistiques et analyses fractographiques de Weibull, quelques résultats sont présentés et discutés. Des évaluations des temps de vie faites dans différentes conditions sont présentées comme étant une fonction des propriétés mécaniques des fibres. L'analyse de la configuration des contraintes corrélées est liée à l'hypothèse réaliste que les fibres seront soumises dans les conditions expérimentales à un champ de contraintes complexe. Les résultats obtenus, avec ceux de la stabilité à court et long terme des points de fusion sont particulièrement importants dans le domaine de la construction mécanique.This paper is an overview of the various parameters determining the mechanical behaviour of the optical fibres. Some recent results are presented and discussed in the light of fracture mechanics, Weibull statistics and surface fractographic analysis. Lifetime evaluations under various service environments are presented as a function of the mechanical properties of the fibre. The combined stress configuration analysis is tied to the realistic assumption that the fibres will be subjected in operation conditions to a complex stress field. The results together with those of short and long term stability of fusion splices, are particularly important to engineering field installations
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