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Mergers and investments in new products
No full textNational audienceThis paper examines how horizontal mergers affect firms’ incentives to invest in R&D leading to the development of new products. We characterize the impact of a merger to monopoly and a 3-to-2 merger on equilibrium innovation efforts and consumer surplus, absent efficiency gains and spillovers. We show that a 3-to-2 merger directly alters the outsider’s innovation incentives by shifting its best-response function upward, and we analyze how this mechanism affects merger outcomes for innovation and consumer surplus. Finally, we examine how efficiency gains and remedies modify post-merger innovation efforts
Fallow land simulations to fight against soil degradation: Engaging stakeholders with model exploration
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/616636/) * Autres projets (id;sigle;titre): AF 1802-001;DSCATT;(FRA) Dynamics of Soil Carbon Sequestration in Tropical and Temperate Agricultural systems//International audienceThis methodological paper forms part of a modelling approach conducted in the Senegalese groundnut basin. It addresses two key aspects: (1) the process of co-constructing the model with local stakeholders; and (2) the use of calibration to account for non-measurable elements, which stakeholders needed to describe and evaluate their system effectively. Thematically, the study examines the relationship between social solidarity and agro-pastoral systems in Diohine, a Senegalese village where communal fallow lands are a vital indicator of socio-ecological resilience. Using the co-constructed, agent-based "Me re Diam" model, we examine the dynamics of soil fertility, population growth and agricultural yields over a 25-year period, integrating local knowledge and ecological data. Our findings emphasise the pivotal role of social solidarity mechanisms, such as parcel lending and food sharing, in stabilising agro-pastoral systems amidst resource scarcity. Calibrating the model demonstrates its ability to reproduce historical dynamics and test alternative practices. Without these mechanisms, the system collapses, revealing their indispensable nature for long-term sustainability. This work emphasises the importance of collaborative modelling in bridging the gap between empirical data and local practices, providing actionable insights for addressing soil degradation and demographic pressures
Mapping the Grandes Gabelles in Early Modern France
No full textThe gabelle salt tax system was a cornerstone of the fiscal apparatus of the early modern French state. This article introduces a novel historical geographic information system (GIS) of this institution's spatial organization as of the seventeenth century, drawing on an original 1665 manuscript map collection: Sanson's Atlas des gabelles. Beyond presenting the dataset and documenting its construction methodology, we provide a detailed account of the functioning of the gabelle, situate the French case in comparative perspective, and illustrate how the availability of this fine-grained dataset expands the possibilities of empirical research in economic history, historical demography, and historical political economy of early modern France
Living bacterial reservoir computers for information processing and sensing
No full textWe introduce a systems-level approach to sensing and computing in which Escherichia coli acts as a living reservoir computer, performing complex information processing through its native growth responses without requiring genetic modification or specialized instrumentation. We validate this framework by accurately classifying early-stage COVID-19 plasma samples (mild vs . severe) using only bacterial growth data, highlighting a diagnostic potential without infrastructure-dependent methods. By controlling nutrient media compositions, we also demonstrate that E. coli growth encodes nonlinear transformations that outperform linear regression, support vector machines, and multilayer perceptrons across diverse regression and classification tasks. Using simulations across genome-scale metabolic models from multiple bacterial species, we establish a strong link between phenotypic diversity and computational capacity, showing that learning capacities scale with the diversity of metabolic phenotypes. These findings position biological reservoir computing as a robust, scalable, and low-cost platform for intelligent biosensing, diagnostics, and hybrid bio-digital computation, while providing new mechanistic insights into the computational capabilities of living systems
Genotyping-by-sequencing reveals marker-based genome stability in tetraploid clementines for triploid breeding
No full textInternational audienceTetraploid non-apomictic citrus genotypes are key female parents for 4x × 2x hybridizations aimed at producing seedless triploid hybrids. However, the extent to which different tetraploidization methods affect genome integrity remains insufficiently characterized at a genome-wide scale. In this study, genotyping-by-sequencing (GBS) was used to evaluate marker-based genomic stability in ten tetraploid plants of 'Clemenules', 'Fina', and 'Marisol' clementines obtained via colchicine treatment, in vitro adventitious organogenesis, or somatic cybridization. Diploid parental plants, two haploid plants of 'Clemenules' and 'Fina' clementines, and one doubled haploid plant of 'Clemenules' clementine were included, being the haploid and double haploid essential to resolve allelic phases. After quality filtering, 3333 SNP (Single Nucleotide Polymorphism) markers distributed across the nine citrus chromosomes were identified and used to compare allele dosage patterns along the genome. Across all GBS-covered regions, no major marker-based genomic gains or losses were detected in any tetraploid plant. These results indicate that, at the resolution provided by GBS, all three tetraploidization methods largely preserve chromosome structure, supporting their suitability for citrus triploid breeding programs based on 4x × 2x sexual hybridizations
Comparative genomic analysis of QTL for resistance to Aphanomyces euteiches between pea, lentil, faba bean, and the model species Medicago truncatula
No full textInternational audienceKey message: QTL mapping and GWAS detected resistance QTL to Aphanomyces euteiches in faba bean, lentil, and Medicago truncatula. Weak genomic conservation between resistance QTL was identified between these legumes and pea.Abstract: QTL mapping and GWAS detected resistance QTL to Aphanomyces euteiches in faba bean, lentil, and Medicago truncatula. Weak genomic conservation between resistance QTL was identified between these legumes and pea. Aphanomyces root rot, caused by Aphanomyces euteiches, is a damaging disease affecting various legume species. Quantitative trait loci (QTL) for partial resistance have been mainly identified in pea, and to a lesser extent in lentil and Medicago truncatula. This study aimed to identify novel resistance loci from available lentil and faba bean populations, and examine genomic conservation of resistance QTL across legume host species. QTL mapping in the Pop2 faba bean recombinant inbred line (RIL) population and genome-wide association study (GWAS) in the AGILE lentil diversity panel were performed for resistance to A. euteiches under controlled conditions, using genotyping data previously reported. A previous QTL mapping in the LR3 M. truncatula RIL population was updated using 1,536 new SNPs (single-nucleotide polymorphisms). Synteny between resistance QTL to A. euteiches was analyzed based on gene orthology in QTL regions projected onto genomes, using the OrthoLegKB graph database. Four loci, including a major-effect QTL on chromosome 3, Ae-Vf3.1, were associated with resistance in faba bean. In lentil, six minor-effect GWAS-SNPs and two favorable haplotypes at Ae-Lc1.1 and Ae-Lc2.1 loci were identified. Updated analyses in M. truncatula narrowed to 8 Kb the interval of the major-effect locus AER1 and revealed three candidate genes. No synteny between major-effect QTL, detected in this study or previously reported in the literature, was identified across grain legume genomes. These results pave the way for translational genomics approaches facilitating resistance gene discovery and for resistance QTL deployment strategies in legume rotations to preserve their durability
Blue and red light-enrichments induce dwarfism in Hydrangea macrophylla through molecular regulation of gibberellin pathway and of cell wall extensibility, without deleterious effects on photosynthetic parameters
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Disruption of putrescine export in experimentally evolved <i>Ralstonia pseudosolanacearum</i> enhances symbiosis with <i>Mimosa pudica</i>
No full textInternational audiencePolyamines are essential molecules across all domains of life, but their role as signaling molecules in host-microbe interactions is increasingly recognized. However, because they are produced by both the host and the microbe, their dual origin makes their functional dissection challenging. The plant pathogenRalstonia pseudosolanacearumGMI1000 secretes large amounts of putrescine bothin vitroand in the xylem sap of host plants. In this study, we investigated the genetic changes underlying its experimental evolution into a legume symbiont. We showed that thepaeAgene (RSc2277), which was repeatedly mutated during this process, encodes a putrescine exporter. Mutations inpaeAcompletely abolished putrescine excretionin vitroand enhanced bacterial proliferation within nodules during interaction with the legumeMimosa pudica. When these mutations occurred in symbionts already capable of intracellular infection, it further increased bacterial load in nodules and allowed the detection of nitrogenase activity. In addition,paeA-mutated symbionts modulated host gene expression towards a more functional symbiotic state by repressing defense-related genes and inducing nodule development genes. These nodule development genes include genes encoding leghemoglobins and an arginine decarboxylase, a key enzyme in plant putrescine biosynthesis. These results indicate that bacterial and plant putrescine have distinct functions in legume symbiosis and highlight the complex role of polyamines in plant-microbe interactions. Importance Rhizobia, the nitrogen-fixing symbionts of legumes, emerged through repeated and independent horizontal transfers of some essential symbiotic genes. However, these transfers alone are often insufficient to convert the recipient bacterium into a functional legume symbiont. In a laboratory experiment, we evolved the plant pathogenRalstonia pseudosolanacearuminto a nodulating and intracellularly infecting symbiont ofMimosa pudica. This transition required genomic modifications in the recipient bacterium to activate its acquired symbiotic potential. Here, we demonstrated that one of these key adaptive modifications is the inactivation of bacterial putrescine export. This polyamine, when produced by the microsymbiont, appears to act as a negative signal for the plant. This study provides new insights into the distinct roles of bacterial- and plant-derived putrescine in plant-microbe interactions, highlighting their functional divergence despite being produced by both organisms.</p
Chapter 11 - Organ communication in insects during growth and development
No full textInternational audienceThis chapter aims at summarizing examples of organ communication and formulating possible underlying principles about the cellular and molecular pathways in insect development and growth. Some of these examples of organ communication are explicitly verbalized as a problem of organ communication in the literature, while others are not, and therefore their inclusion here relies on my interpretation. Generally, we distinguish between the embryo that develops and differentiates in a closed system within the egg case and the stages outside the embryo and before metamorphosis that constantly receive information especially nutrients from an open system, the environment
New weighted Riesz-type pointwise inequalities and applications to generalized Sobolev estimates
No full textIn this article we study some new pointwise inequalities between rough singular integral operators, weighted maximal functions of the gradient and weighted Morrey spaces. These pointwise estimates will naturally lead us to a new class of weighted Sobolev-type inequalities