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L\u27identité linguistique et culturelle de la jeune génération des Vietnamiens Américains en Louisiane
No full textCette thèse porte sur la construction de l’identité linguistique et culturelle chez les jeunes Vietnamiens américains de deuxième génération vivant à Bâton Rouge, aux États-Unis. Elle interroge les modalités de transmission, de transformation et de réappropriation de la culture et de la langue vietnamienne dans un contexte diasporique marqué par des tensions entre héritage familial et pression d’intégration dans la société américaine.
À partir d’une approche qualitative et narrative, cette recherche s’appuie sur huit entretiens approfondis menés auprès de jeunes adultes âgés de 18 à 25 ans. L’objectif est de comprendre comment ces jeunes construisent leur identité à travers leurs expériences personnelles, leurs pratiques linguistiques et culturelles, et les étiquettes qu’ils choisissent pour se définir.
La première partie de la thèse propose une contextualisation historique, théorique et méthodologique de l’étude. Elle présente l’histoire migratoire vietnamienne, puis s’appuie sur des travaux en sociolinguistique, psychologie interculturelle et études diasporiques pour penser des notions telles que le bilinguisme, l’hybridité, la transmission intergénérationnelle ou encore le changement de cadre.
La seconde partie présente une analyse détaillée des récits recueillis. Le chapitre 5 explore les formes de transmission familiale, les tensions identitaires, et les dynamiques de biculturalité et d’hybridation. Le chapitre 6 approfondit le rôle de la langue vietnamienne, non seulement comme outil de communication, mais aussi comme vecteur d’appartenance, de mémoire et de positionnement identitaire.
Les résultats montrent que l’identité des jeunes Vietnamiens américains est fluide, contextuelle et en constance négociation. La plupart des participants revendiquent une identité composée « Vietnamienne américaine », qu’ils déclinent selon deux logiques principales : une logique biculturelle (coexistence parallèle) et une logique hybride (recomposition personnelle). La langue vietnamienne y joue un rôle ambivalent : affectivement valorisée, elle peut aussi devenir source de distance ou de conflit. Cette étude met en lumière la complexité des parcours identitaire diasporiques contemporains, en montrant comment les jeunes conjuguent l’héritage et l’adaptation pour construire des formes de soi plurielles, mouvante et situées
Modeling and forecasting vibrio vulnificus concentration of long-range dependence on marine environmental conditions
No full textVibrio vulnificus (vvh) is an epidemiologically significant bacterium that naturally occurs in coastal waters under favorable environmental conditions and causes one of the highest mortality rates among known foodborne pathogens. Little is currently known about the environmental conditions that favor the abundance of vvh particularly in seafood like oysters. By synergistically combining 13 years of field oyster sampling-based vvh concentration data from environmentally distinct coastal waters, satellite remote sensing-based environmental data, and the Artificial Intelligence-based machine learning technique, this paper presents new insights into the favorable environmental conditions and new ensemble models for forecasting the vvh concentration in oysters. Specifically, it was discovered that the concentration of vvh in oysters is controlled by antecedent conditions of seven environmental predictors, including solar radiation (SR), water level (WL), wind speed (WS), chlorophyll a (CHL), pH, water temperature (SST), and salinity (SSS). The key novelty of this work is the discovery of SR as being the most important predictor of vvh despite its high correlation with SST. WL is the second (or third) most important predictor of vvh. It was also discovered that there is a long-range dependence of vvh concentration on antecedent conditions of the seven environmental predictors up to 80 days before. This is another novel contribution of this work. Based on the findings, four XGBoost ensemble models with varying lead times were presented for forecasting the vvh concentration in oysters, providing a scientific basis and sufficient response time for proactive management interventions to protect public health from potential vvh infections
Associations between household characteristics and environmentally persistent free radicals in house dust from two Australian locations
No full textIntroduction: The association between air pollution and adverse health outcomes has been extensively documented, with oxidative stress widely considered a contributing factor. However, the precise underlying mechanism(s) remains unclear. Recent studies suggest that environmentally persistent free radicals (EPFRs) may provide the missing connection between air pollution and its detrimental health effects. Nevertheless, the indoor environment has received limited attention in EPFR research. Therefore, in this study, we measured EPFRs in house dust samples from two locations in Australia and examined household characteristics associated with their presence. Methods: Household characteristics and behaviours that influence indoor air quality were collected from an online questionnaire; 24-h indoor and outdoor air quality were measured with a TSI DustTrak™ DRX Aerosol monitor 8,533; annual indoor and outdoor air quality were matched to two validated, satellite-based land-use regression models; and dust samples were collected from house vacuums. Dust samples were analyzed using nano electron paramagnetic resonance (EPR) to determine spin concentrations, g-factor, and delta H peak-to-peak (Hp-p). Key variables were identified using Lasso-penalized regression models, followed by unpenalized linear regression and post-selection inference to estimate coefficients and assess the robustness of the findings. Results: Our analysis revealed that factors such as extractor fan usage during cooking, exposure to traffic-related air pollution and ambient PM2.5 levels, indoor combustion activities, seasonal variation, housing construction type, ventilation, and cleaning practices were significantly associated with EPFR concentrations in Australian homes. Notably, consistent use of extractor fans during cooking was strongly and consistently associated with lower EPFR concentrations in house dust across both study locations. Discussion: Our research provided insight into the potential impact of household characteristics on EPFR concentrations, which can potentially lead to adverse health effects. Future research should link our research findings on factors affecting indoor EPFRs to their potential health effects
Host Plant Resistance to Stink Bugs in Commercial Soybean Varieties
No full textSoybean, Glycine max (L.) Merr. (Fabales: Fabaceae), is a major crop in Louisiana, where stink bugs (Hemiptera: Pentatomidae) are economically important pests that reduce seed quality and yield. Among them, the redbanded stink bug, Piezodorus guildinii (Westwood), is considered the most damaging species in the southern U.S. soybean system. Recently, Euschistus quadrator (Rolston), historically a minor pest, has increased in abundance and now dominates the brown stink bug complex in Louisiana soybean fields. While P. guildinii has been widely studied, little is known about E. quadrator.
Given the increasing pest complexity, sustainable management strategies are needed to target the entire stink bug complex. Host plant resistance is a promising IPM tool to reduce insecticide use and improve long-term control. Understanding species-specific biology, plant variety interactions, and population dynamics is essential to support Integrated Pest Management (IPM).
This study aimed to: (1) characterize the survival and reproductive biology of E. quadrator on soybean under laboratory conditions; (2) evaluate the susceptibility of commercial soybean varieties to P. guildinii using life table studies; and (3) assess field resistance of soybean varieties to stink bug infestations using a seed damage index and 100-seed weight as a yield proxy.
In laboratory experiments, first-instar nymphs of both species were reared on pods of different soybean varieties under controlled conditions. Development, survival, and reproduction were recorded, and demographic parameters were estimated using life table analysis. Field experiments over three seasons used replicated plots, weekly sweep net sampling to monitor stink bug pressure, and postharvest assessments of seed damage and 100-seed weight.
Results confirmed that E. quadrator can complete its life cycle on soybean, reinforcing its status as an emerging pest. For P. guildinii, differences among varieties in development and survival suggest antibiosis resistance. Field data showed notable variation in infestation and damage, with some varieties exhibiting antixenosis and tolerance. These findings indicate that commercial soybean varieties in the southern U.S. differ in their resistance to stink bugs, and this variation can be used to support sustainable IPM programs
THE SHREW OF NAGALAND: A REMARKABLE NEW GENUS AND SPECIES FROM NORTHEAST INDIA, WITH A DISCUSSION OF THE PHYLOGENY AND CLASSIFICATION OF THE SORICIDAE (MAMMALIA)
No full textA new genus and species of extant shrew, Nagasorex albidens, is described based on a single specimen obtained in Nagaland, northeastern India, in 1950. The new species shows novel characters, such as a total tooth number of 34, not found in any extant genus though they are found in extinct genera such as †Miosorex, †Lartetium, †Pseudotrimylus, and †Domnina. To determine the phylogenetic relationships of the new species, we first analyzed craniodental characters from all extant and many extinct genera of Soricidae. Although statistical support for most nodes was low, the nearest relatives of the new taxon appear to be certain Miocene and Pliocene taxa from Europe and Asia—†Dobenflorinia (new name), †Clapasorex, †Miosorex, and †Crocidosorex—followed by the extant African genera Congosorex, Myosorex, and Surdisorex, all of which we treat as members of the Myosoricinae. We then conducted a molecular phylogenetic study of extant genera using mitochondrial and nuclear genes. Although the genetic data we obtained from the new shrew are limited, our results place Nagasorex as the sister taxon of Crocidurinae (mitochondrial genes), or sister to Myosoricinae + Crocidurinae (nuclear genes). We tentatively place the new genus in the Myosoricinae. Additionally, we replace the preoccupied generic name Soricella with a new name, Dobenflorinia. Based on these results, we present a new systematic arrangement of the Soricidae
A reference genome for boat-tailed grackles (Quiscalus major)
No full textBoat-tailed Grackles (Quiscalus major) are marsh-dwelling blackbirds that are endemic to the eastern United States. Various aspects of their biology have been studied extensively, including their mating system, plumage and molt patterns, diet, and interspecific interactions. Boat-tailed Grackles are also interesting because they exhibit variation in their iris color that is associated with geography. However, resources that enable genomic studies of Boat-tailed Grackles and other related grackle species are few. Here, we combined Pacific Biosciences long-read, HiFi data with short-read Illumina data from a HiC library to produce haplotype-phased, chromosome-scale genome assemblies for Boat-tailed Grackles. The final version of the assembly, bQuiMaj1, includes two, contiguous haplotypes with total lengths of ~1 Gbp, N50s of ~70 Mbp, and L50s of 5-6. BUSCO and merqury analyses suggest both haplotypes are also relatively complete (95-99%) with respect to gene and k-mer content. The resulting assemblies will significantly enhance our understanding of Boat-tailed Grackle biology and physiology, as well as contribute to the growing number of genomes representing species belonging to the taxonomic family Icteridae (the New World blackbirds)
The Agrobacterium fabrum efflux pump PecM is produced in response to the plant exudate 4-hydroxybenzaldehyde to avoid disruption of central metabolism
No full textAgrobacterium fabrum is a phytopathogen that causes crown gall disease. In the rhizosphere, it encounters plant exudates, some of which are toxic, such as 4-hydroxybenzaldehyde (4HBA). Others, including 4-hydroxybenzoate (4HB), participate in the induction of virulence genes. A. fabrum encodes the transcription factor PecS, which has been reported to enhance bacterial fitness in the rhizosphere. The gene encoding PecS is divergent from pecM, which encodes an efflux pump. PecS represses both pecS and pecM, as evidenced by increased expression in the presence of the PecS ligand urate and by elevated pecM expression in a pecS disruption strain. We report here that the expression of pecM is induced selectively by 4HBA. Expression of genes encoding enzymes involved in the degradation of 4HB is induced by both 4HBA and 4HB, as expected; however, overexpression of pecM attenuates the induction by 4HBA, suggesting that 4HBA is a substrate for PecM. Consistent with this inference, untargeted metabolomics shows that 4HBA accumulates intracellularly when pecM is disrupted. Analysis of PecS by thermal stability assay and DNase I footprinting suggests that 4HBA is not a ligand for PecS. Taken together, our data suggest that 4HBA is a substrate for PecM
Regional Economic Outcomes: A Comprehensive Analysis of Disasters, Vulnerability, and the Effects of Disamenities
No full textThis paper explores how regional economies respond to external shocks such as natural disasters, socioeconomic vulnerabilities, and amenity factors through three chapters. These studies aim to identify the mechanisms by which external disturbances have an impact on regional industries and development.
The first chapter quantifies the economic impacts of hurricanes across industry sectors using 15 years of county-level data in the United States. By categorizing regional economies into agriculture, manufacturing, trade, and services, it examines how hurricane damage affects employment and GDP by sector, including the delayed effects of short- and medium-term hurricanes.
The second chapter constructs a comprehensive community vulnerability index (CCVI) that integrates vulnerabilities at the business and public levels beyond the private (household) level of a region to measure regional vulnerability. Extending the concept from existing indices that focus mainly on household-level socioeconomic factors, this new framework integrates the dimensions of the business and public sectors to provide a more holistic and place-based assessment of community vulnerability. It also explores the potential applicability of the CCVI by considering exposure to climate-related hazards, thereby constructing a Climate-Enhanced Comprehensive Community Vulnerability Index (CE-CCVI). This chapter is expected to be applicable to sectoral planning and response strategies based on regional vulnerability in regions with varying levels of vulnerability.
The third chapter examines the effects of both natural and man-made amenities and disamenities on regional economic performance with respect to population, employment, and income. The study shows that amenities support development, while pollution and natural disasters hinder development. This contrast highlights the dual role of these factors in shaping regional performance. Finally, this chapter explores the key determinants of regional growth as shaped by population scale and proximity to urban areas.
This collection of studies contributes to a comprehensive understanding of regional economic vulnerability and resilience. By integrating the analysis of industry specific-impacts of disasters, the construction of a comprehensive regional vulnerability index, and the discussion of amenities and disamenities as a driver of regional growth, this paper concretizes the impact of external shocks on the regional economy and provides a basis for designing policies for various exogenous factors
Frontal polymerization in thin layers: Hydrodynamic effects and asymptotic dynamics
No full textBuoyancy-driven convection currents arise from temperature gradients in thermal frontal polymerization (FP) when the spatially localized polymerization reaction travels perpendicularly to the gravity field. We propose a theoretical study of the system dynamics under adiabatic conditions. The polymer and the reactant mixture are considered to be in the same liquid phase, but the viscosity can increase with the degree of polymerization. We find that the reaction zone propagates as a hot spot-like pattern with a broken symmetry in both the vertical and horizontal directions. Furthermore, the system can reach an asymptotic dynamics characterized by a front with a steady shape that propagates at constant speed with a steady vortex surrounding it. As the strength of the vortex is increased, either by decreasing the reactants’ viscosity or by increasing the layer’s thickness, we observe a transition between (i) a passive regime predicted by pure reaction-diffusion and hydrodynamic models and (ii) an active chemo-hydrodynamic regime where such models separately break down. In the active regime (ii), the front speed decreases as convection intensifies. By means of a scaling analysis, we explain how hydrodynamic currents might lower the velocity of a polymerization wave. As the viscosity of the polymer is enlarged, the flow is shifted ahead of the reaction zone and becomes more symmetrical with respect to the middle of the system, as recently observed in solid-liquid FP experiments [Y. Gao et al., Phys. Rev. Lett. 130, 028101 (2023) and Y. Gao et al., Int. J. Heat Mass Transf. 240, 126622 (2025)]
Inhibitors of the Bacterioferritin Ferredoxin Complex Dysregulate Iron Homeostasis and Kill Acinetobacter baumannii and Biofilm-Embedded Pseudomonas aeruginosa Cells
No full textIn Pseudomonas aeruginosa, the iron storage protein bacterioferritin (Bfr) contributes to buffering cytosolic free iron concentrations by oxidizing Fe2+ and storing the resultant Fe3+ in its internal cavity, and by forming a complex with a cognate ferredoxin (Bfd) to reduce the stored Fe3+ and mobilize Fe2+ to the cytosol. Small molecule derivatives of 4-aminoisoindoline-1,3-dione designed to bind P. aeruginosa Bfr (Pa Bfr) at the Bfd binding site accumulate in the P. aeruginosa cell, block the Pa Bfr-Bfd complex, inhibit iron mobilization from Pa Bfr, elicit an iron starvation response, are bacteriostatic to planktonic cells, and are bactericidal to biofilm-entrenched cells. A structural alignment of Pa Bfr and Acinetobacter baumannii Bfr (Ab Bfr) showed strong conservation of the Bfd binding site on Ab Bfr. Accordingly, the small molecule inhibitors of the Pa Bfr-Bfd complex accumulate in the A. baumannii cells, elicit an iron starvation response, are bactericidal to planktonic cells, and exhibit synergy with existing antibiotics. These findings indicate that the inhibition of iron mobilization from Bfr may be an antimicrobial strategy applicable to other Gram-negative pathogens