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Classification of gamma-ray targets for velocity-dependent and subhalo-boosted dark-matter annihilation
Thomas Lacroix, Gaetán Facchinetti, Judit Pérez Romero, Martin Stref, Julien Lavalle, David Maurin, Miguel Sánchez-Conde, original scientific article

Abstract: Gamma-ray observations have long been used to constrain the properties of dark matter (DM), with a strong focus on weakly interacting massive particles annihilating through velocity-independent processes. However, in the absence of clear-cut observational evidence for the simplest candidates, the interest of the community in more complex DM scenarios involving a velocity-dependent cross-section has been growing steadily over the past few years. We present the first systematic study of velocity-dependent DM annihilation (in particular p-wave annihilation and Sommerfeld enhancement) in a variety of astrophysical objects, not only including the well-studied Milky Way dwarf satellite galaxies, but nearby dwarf irregular galaxies and local galaxy clusters as well. Particular attention is given to the interplay between velocity dependence and DM halo substructure. Uncertainties related to halo mass, phase-space and substructure modelling are also discussed in this velocity-dependent context. We show that, for s-wave annihilation, extremely large subhalo boost factors are to be expected, up to 10^11 in clusters and up to 10^6–10^7 in dwarf galaxies where subhalos are usually assumed not to play an important role. Boost factors for p-wave annihilation are smaller but can still reach 10^3 in clusters. The angular extension of the DM signal is also significantly impacted, with e.g. the cluster typical emission radius increasing by a factor of order 10 in the s-wave case. We also compute the signal contrast of the objects in our sample with respect to annihilation happening in the Milky Way halo. Overall, we find that the hierarchy between the brightest considered targets depends on the specific details of the assumed particle-physics model.
Keywords: dark matter theory, dwarf galaxies, galaxy clusters, gamma-ray theory
Published in RUNG: 27.01.2023; Views: 1266; Downloads: 0
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The molecular toolbox of ectomycorrhizal-driven phosphate mineral weathering
Christina Paparokidou, Leake Jonathan R., Rolfe Stephen A., Beerling David J., 2022, published scientific conference contribution abstract

Abstract: Ectomycorrhizal fungi (EMF) form symbiotic partnerships with tree roots and are able to chemically weather inorganic phosphorus (Pi)-rich minerals, supplying Pi to their host in return for photosynthates. The fungal-driven nutrient cycling from mineral weathering plays a pivotal role in ecosystems and crops productivity, as well as geochemical cycles. The aim of the study presented in this thesis is to unravel the molecular mechanisms by which the EM fungus Paxillus involutus weathers the Pi-rich mineral hydroxyapatite (HAP), either non-symbiotically or in symbiosis with its host tree Pinus sylvestris. Development of an artificial system to study P. involutus responses to varying concentration of Pi led to the identification of five high-affinity Pi transporter genes, of which the expression varies in an inversely proportional manner to Pi availability. Using the same system, whole-transcriptomic data from fungal hyphae unravelled the molecular basis of the EMF ability in Pi uptake at the global gene scale, revealing that EM symbiosis can directly affect Pi-responsive fungal genes such as the Pi transporter PiPT4. A second artificial system was used to study HAP solubilisation driven by P. involutus, which was confirmed by EDX spectroscopy data showing depletion of Pi from the HAP crystals, along with secondary minerals formation. Whole-transcriptomic analysis revealed that EM symbiosis induces a different set of HAP weathering genes in P. involutus hyphae, compared to the fungus growing non-symbiotically, including the specific expression of organic acid metabolic genes, which resulted in enhanced HAP solubilisation. Metabolomic analysis led to the identification of multiple secreted metabolites enriched in the presence of HAP in P. involutus systems grown non-symbiotically or in symbiosis with P. sylvestris seedlings. The analysis also led to the identification of putative novel fungal weathering agents. Results from transcriptomic and metabolomic analyses were ultimately combined in a model of HAP weathering by P. involutus.
Keywords: Paxillus involutus, Pinus Sylvestris, ectomycorrhizal symbiosis, mineral weathering, hydroxyapatite, RNA-seq, SEM-EDS, UPLC-Q-TOF-MS
Published in RUNG: 18.01.2023; Views: 1145; Downloads: 0
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Voces de la literatura infantil y juvenil eslovena actual
Barbara Pregelj, Barbara Pregelj, David Heredero Zorzo, Santiago Martín, 2021, professional monograph

Abstract: 10 slovenskih mladinskih avtorjev, ki so prevedeni v španščino
Keywords: slovenska literatura, mladinska književnost, prevodi v španščino
Published in RUNG: 22.09.2022; Views: 1351; Downloads: 0

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Phosphate availability and ectomycorrhizal symbiosis with Pinus sylvestris have independent effects on the Paxillus involutus transcriptome
Christina Paparokidou, Jonathan R. Leake, David J. Beerling, Stephen A. Rolfe, 2021, original scientific article

Abstract: Many plant species form symbioses with ectomycorrhizal fungi, which help them forage for limiting nutrients in the soil such as inorganic phosphate (Pi). The transcriptional responses to symbiosis and nutrient-limiting conditions in ectomycorrhizal fungal hyphae, however, are largely unknown. An artificial system was developed to study ectomycorrhizal basidiomycete Paxillus involutus growth in symbiosis with its host tree Pinus sylvestris at different Pi concentrations. RNA-seq analysis was performed on P. involutus hyphae growing under Pi-limiting conditions, either in symbiosis or alone. We show that Pi starvation and ectomycorrhizal symbiosis have an independent effect on the P. involutus transcriptome. Notably, low Pi availability induces expression of newly identified putative high-affinity Pi transporter genes, while reducing the expression of putative organic acid transporters. Additionally, low Pi availability induces a close transcriptional interplay between P and N metabolism. GTP-related signalling was found to have a positive effect in the maintenance of ectomycorrhizal symbiosis, whereas multiple putative cytochrome P450 genes were found to be downregulated, unlike arbuscular mycorrhizal fungi. We provide the first evidence of global transcriptional changes induced by low Pi availability and ectomycorrhizal symbiosis in the hyphae of P. involutus, revealing both similarities and differences with better-characterized arbuscular mycorrhizal fungi.
Keywords: Ectomycorrhizal symbiosis, Paxillus involutus, Pi transporters, Pi-starvation, Pinus sylvestris, RNA-seq.
Published in RUNG: 03.05.2022; Views: 1373; Downloads: 0
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Ljubka Šorli (1910-1993) : znanstvena monografija ob stoletnici pesničinega rojstva
2010, scientific monograph

Keywords: slovenske pesnice
Published in RUNG: 19.04.2022; Views: 1548; Downloads: 0

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