Latest Articles
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Section: Animal Science ; Topics: Agricultural sciences, Applied mathematics
Dynamic sensitivity analysis of a mathematical model describing the effect of the macroalgae Asparagopsis taxiformis on rumen fermentation and methane production under in vitro continuous conditions
10.24072/pcjournal.644 - Peer Community Journal, Volume 5 (2025), article no. e126
Get full text PDFRuminants play an important role in global warming by emitting enteric methane (CH4) through the degradation of feeds by the rumen microbiota. To better understand the dynamics fermentation outputs, including CH4 and volatile fatty acids (VFA) production, mathematical models have been developed. Sensitivity analysis (SA) methods quantify the contribution of model input parameters (IP) to the variation of an output variable of interest. In animal science, SA are usually conducted in static condition. In this work, we hypothesized that including the dynamic aspect of the rumen fermentation to SA can be useful to inform on optimal experimental conditions aimed at quantifying the key mechanisms driving CH4 and VFA production. Accordingly, the objective of this work was to conduct a dynamic SA of a rumen fermentation model under in vitro continuous conditions (close to the real in vivo conditions). Our model case study integrates the effect of the macroalgae Asparagopsis taxiformis (AT) on the fermentation. AT has been identified as a potent CH4 inhibitor via the presence of bromoform, an anti-methanogenic compound. We computed Shapley effects over time for quantifying the contribution of 16 IPs to CH4 (mol/h) and VFA (mol/l) variation. Shapley effects integrate the three contribution types of an IP to output variable variation (individual, via the interactions and via the dependence/correlation). We studied three diet scenarios accounting for several doses of AT relative to Dry Matter (DM): control (0% DM of AT), low treatment (LT: 0.25% DM of AT) and high treatment (HT: 0.50% DM of AT). Shapley effects revealed that hydrogen (H2) utilizers microbial group via its Monod H2 affinity constant highly contributed (> 50%) to CH4 variation with a constant dynamic over time for control and LT. A shift on the impact of microbial pathways driving CH4 variation was revealed for HT. IPs associated with the kinetic of bromoform utilization and with the factor modeling the direct effect of bromoform on methanogenesis were identified as influential on CH4 variation in the middle of fermentation. Whereas, VFA variation for the three diet scenarios was mainly explained by the kinetic of fibers degradation, showing a high constant contribution (> 30%) over time. The simulations computed for the SA were also used to analyze prediction uncertainty. It was related to the dynamic of dry matter intake (DMI, g/h), increasing during the high intake activity periods and decreasing when the intake activity was low. Moreover, CH4 (mol/h) simulations showed a larger variability than VFA simulations, suggesting that the reduction of the uncertainty of IPs describing the activity of the H2 utilizers microbial group is a promising lead to reduce the overall model uncertainty. Our results highlighted the dynamic nature of the influence of metabolic pathways on CH4 productions under an anti-methanogenic treatment. SA tools can be further exploited to design optimal experiments studying rumen fermentation and CH4 mitigation strategies. These optimal experiments would be useful to build robust models that can guide the development of sustainable nutrition strategies.
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Section: Archaeology ; Topics: Archaeology, Anthropology, History
Rethinking Caribbean Archaeology: Towards an ethical position for a truly decolonial practice
Herrera Malatesta, Eduardo;
Fricke, Felicia J.;
de Waal, Maaike;
Seferidou, Eleni;
Cunningham, Andreana;
Nägele, Kathrin;
Victorina, Amy;
kok, marjolijn;
Chiappa, Oriana;
Farmer, Kevin;
van Litsenburg, Zoë;
Aguasvivas, Marianny;
Ammerlaan, Lauriane
10.24072/pcjournal.648 - Peer Community Journal, Volume 5 (2025), article no. e125
Get full text PDFCaribbean archaeology faces urgent ethical challenges rooted in colonial histories, global inequities, and local socio-political realities. This paper advances a decolonial framework for addressing these issues, grounded in best practices emerging from a workshop held in late 2023. Specifically, we: (1) summarize the key issues discussed, (2) present the goals of our network in tackling them, and (3) define our priorities for fostering ethical archaeological and heritage practices in the Caribbean. While many of these challenges resonate beyond the region, we argue that their resolution requires context-specific, Caribbean-oriented strategies. Our aim is not to provide a comprehensive catalogue of ethical issues and solutions, nor to imply that projects omitting the aspects we emphasize are inherently unethical. Rather, we seek to establish a foundation for sustained dialogue and debate on ethics in Caribbean archaeology, encouraging engagement among both local and international researchers. Although we acknowledge the vital role of communities in shaping archaeological practice, this paper reflects the disciplinary perspective of professional archaeologists, oriented toward fulfilling our ethical and social responsibilities to those communities. In doing so, we hope to contribute to a more equitable and contextually grounded archaeological practice in the Caribbean.
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Section: Ecotoxicology & Environmental Chemistry ; Topics: Environmental sciences
Investigation of the combined influence of salinity and particle concentration on the adsorption of anionic and zwitterionic PFAS onto estuarine sediment using the RSM modelling approach
10.24072/pcjournal.645 - Peer Community Journal, Volume 5 (2025), article no. e124
Get full text PDFSalinity (S) and suspended particulate matter (SPM) are key factors influencing the sorption of micropollutants in estuaries, due to strong gradients in these ecosystems. Previous laboratory or field-based studies have typically investigated the impact of S or SPM separately. Thus, the combined effects of S and SPM as well as their interactions on the sorption of micropollutants such as per- and polyfluoroalkyl substances (PFAS) in estuarine environments still remain poorly understood. We initially investigated the adsorption kinetics of 11 anionic and zwitterionic PFAS onto estuarine sediment under one S/SPM combination in laboratory-controlled conditions, as well as their adsorption isotherms under two S/SPM combinations. We also determined their distribution coefficients (Kd) across 35 S/SPM combinations covering a wide range of estuarine conditions. The adsorption kinetics of PFAS could be described by a pseudo-second-order model (equilibrium time <24h). Sorption isotherms were fitted by both linear and Freundlich models; the linear sorption range was in the range 0.12–1.31 nM and Kd varied between 0.6 and 55271 L/kg. Based on response surface modelling, both S and SPM were significant factors, i.e. Kd was positively related to S (salting-out effect), while it was negatively related to SPM concentration (third-phase effect). SPM had a stronger effect than S for short-chain carboxylates, whereas S was the dominant factor for most other compounds. We also present, for the first time, evidence of a significant negative interaction between these two factors. This study therefore provides a new perspective to model the fate of PFAS at the land-sea interface.
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Section: Evolutionary Biology ; Topics: Ecology, Evolution
Asymmetric performance in early life stages of hybrid Argiope bruennichi
10.24072/pcjournal.649 - Peer Community Journal, Volume 5 (2025), article no. e123
Get full text PDFHybridisation of different species or isolated populations is an important driver of animal speciation. Hybrid populations oftentimes outperform their parent populations due to novel genetic combinations, exhibiting hybrid vigour. Conversely, hybridisation can also lead to worse performance due to outbreeding depression. The wasp spider Argiope bruennichi has undergone a hybridisation event with Mediterranean and Asian populations mixing and resulting in a genetically distinct Northern European population. With this study we tested if hybrid offspring could outperform their parent populations under novel, disadvantageous conditions, namely climate and food availability. We found that spiders with a Mediterranean mother and an Asian father had very low hatching rates and high mortality and slow growth compared to the pure lines, and spiders with Asian mothers and Mediterranean fathers performed comparably to their parent populations. These results suggest mitonuclear incompatibility of the first combination and an increased role of the second in the stabilization process of a hybridising population. Additionally, we observed extreme developmental plasticity as a reaction to climatic cues in all backgrounds, which likely aided in the rapid historic poleward range expansion of this species.
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The network image was drawn by Martin Grandjean: A force-based network visualization CC BY-SA