This paper investigates the persistence of agricultural practices funded by the California Department of Food and Agriculture's Office of Environmental Farming and Innovation (CDFA OEFI). The central inquiry revolves around determining the most effective behavior model for analyzing persistence, comparing the Reasoned Action Approach (RAA), Comprehensive Action Determination Model (CADM), and CADM augmented with structural variables. The study's methodology integrates literature review, analysis of OEFI-funded practices, and statistical modeling to assess persistence levels. Contrary to existing literature, our findings reveal significantly higher levels of persistence than anticipated. Moreover, through model comparison, CADM augmented with political economic variables emerges as the superior model for analyzing and predicting persistence in agricultural practices funded by CDFA OEFI. These results contribute to a deeper understanding of behavioral determinants in sustainable agricultural practices and offer insights into optimizing policy interventions for long-term practice adoption and environmental impact.

Amidst the turbulence of political shifts and the re-emergence of the Taliban, this phenomenological research shines a light on the lived experiences, aspirations, and challenges of female undergraduate students in an Afghan university. Through in-depth, qualitative interviews, this study unravels six pivotal themes shaping their collegiate journey: gender-centric oppression, systemic and structural barriers, academic hindrances, family support, and the motivation to endure and prevail amidst profound adversities, such as enforced gender apartheid and stringent clothing mandates. Within an intersectionality framework, this research not only bridges a critical gap in the literature but also serves as a crucial narrative for global academia and policy-making arenas, underlining the imperative for robust advocacy and policy reforms. The stark findings and nuanced insights gleaned from this study underscore the imperative to foster gender equality and educational access, whilst advocating fervently for the re-establishment of inclusive and supportive educational environments for all in Afghanistan.

Hispanics represent the greatest U.S. population growth, yet Hispanic women are the least educated of all U.S. ethnic female groups and reflect the lowest college enrollment as a percent of their total population. Since nearly half of Hispanics enrolled in college are served by community colleges, this research sought to understand if marianismo, i.e., the cultural expectations that Hispanic women females must focus on caretaking and mothering while reflecting passivity, duty and honor, and self-sacrifice, might provide some explanation for the low levels of degree attainment among Hispanic female community college students compared to their female peers from all other ethnic groups. Marianismo was once a construct that limited the role of women to the home. However, today’s Hispanic female is expected to juggle home priorities along with other roles in which she may engage. These various role demands may influence Hispanic female college persistence and success. Using secondary data analysis of the national Educational Longitudinal Study 2002 (ELS), this study examined the relationship between marianismo and persistence (semester to semester enrollment) of Hispanic females (n = 368) enrolled in community colleges. To create a marianismo scale, 13 items were selected from the ELS and reviewed by individuals familiar with Hispanic culture and marianismo. Confirmatory factor analysis was then used to generate a reliable marianismo scale (Cronbach’s alpha = .82). Logistic regression revealed that of marianismo, socio-economic status, generational status, and high school GPA, only high school GPA was statistically significant for predicting persistence.

Yersinia pestis, agent causal de la peste, persiste dans la nature maintenu par un cycle enzootique dans des foyers conduisant à la réémergence de la maladie. En Afrique du Nord, où une réémergence a eu lieu après des années de ‘silence’, nous avons répertorié les différents épisodes ainsi que le nombre de cas en sur six pays à compter de 1940 en mettant en évidence l’importation de la maladie et un mode de contamination négligé, la transmission par voie orale. Une étude en Algérie sur 237 micromammifères confirme deux foyers et en revèle trois nouveaux porteurs d’un nouveau génotype (MST) de biotype Orientalis. Apodemus sylvaticus est par la même ajouté à la liste des rongeurs pestiférés. La projection des foyers de peste ainsi actualisés sur une carte géographique et écologique met en évidence la proximité des foyers de peste aux points d’eau saumâtre. Une étude statistique a confirmé une corrélation significative entre foyer de peste/eau salée à une proximité minimale <3 km en comparaison à des zones d’eau douce. Des échantillons environnementaux salés ont permis l’isolement d’une souche Y. pestis Algeria 3. Cette découverte confortée par l’observation expérimentale de la résistance de Y. pestis à un milieu hyper salé à 150g/L NaCl se traduisant par un protéome spécifique en réponse à ce stress avec une forme d’adaptation de type forme L de la bactérie dans ce type d’environnement. Notre travail éclaire de façon originale un facteur méconnu de persistance tellurique de Y. pestis, conditionnant la réémergence de la peste dans des foyers séculaires au Maghreb contrairement aux rivages Nord de la Méditerranée où la peste autochtone a disparu depuis un siècle. / Yersinia pestis, the causal agent of plague, persists in nature maintained by an enzootic cycle in foci leading to the re-emergence of the disease. In North Africa, where re-emergence took place after years of 'silence', we have listed the various episodes and the number of cases in six countries from 1940 onwards, highlighting the importation of the disease and A method of neglected contamination, oral transmission. A study in Algeria on 237 micromammals confirms two foci and reveals three new carriers of a new genotype (MST) of orientalis biotype. Apodemus sylvaticus is by the same added to the list of plague rodents. The projection of the plague foci thus updated on a geographical and ecological map highlights the proximity of plague foci to brackish water points. A statistical study confirmed a significant correlation between plague / salt water at a minimal proximity <3 km compared to freshwater areas. Saline environmental samples allowed the isolation of a Y. pestis Algeria 3 strain. This discovery was confirmed by the experimental observation of the resistance of Y. pestis to a hyper-saline medium at 150 g / L NaCl resulting in a specific proteome In response to this stress with an adaptation form of form L of the bacterium in this type of environment. Our work illuminates in an original way an unknown factor of telluric persistence of Y. pestis, conditioning the re-emergence of the plague in secular centers in the Maghreb unlike the northern shores of the Mediterranean where the indigenous plague has disappeared for a century.

Dans cette thèse nous nous intéressons aux équations de réaction-diffusion et à leurs applications en sciences biologiques et médicales. Plus particulièrement on étudie l'existence ou la non-existence de phénomènes de propagation en milieux hétérogènes à travers l'existence d'ondes progressives ou plus généralement l'existence de fronts de transition généralisés. On obtient des résultats d'existence de phénomènes de propagation dans trois environnements différents. Dans un premier temps on étudie une équation de réaction-diffusion de type bistable dans un domaine extérieur. Cette équation modélise l'évolution de la densité d'une population soumise à un effet Allee fort dont le déplacement suit un processus de diffusion dans un environnement contenant un obstacle. On montre que lorsque l'obstacle satisfait certaines conditions de régularité et se rapproche d'un domaine étoilé ou directionnellement convexe alors la population envahit tout l'espace. On se questionne aussi sur les conditions optimales de régularité qui garantissent une invasion complète de la population. Dans un deuxième travail, nous considérons une équation de réaction-diffusion avec vitesse forcée, modélisant l'évolution de la densité d'une population quelconque qui se diffuse dans l'espace, soumise à un changement climatique défavorable. On montre que selon la vitesse du changement climatique la population s'adapte ou s'éteint. On montre aussi que la densité de population converge en temps long vers une onde progressive et donc se propage (si elle survit) selon un profile constant et à vitesse constante. Dans un second temps on étudie une équation de réaction-diffusion de type bistable dans des domaines cylindriques variés. Ces équations modélisent l'évolution d'une onde de dépolarisation dans le cerveau humain. On montre que l'onde est bloquée lorsque le domaine passe d'un cylindre très étroit à un cylindre de diamètre d'ordre 1 et on donne des conditions géométriques plus générales qui garantissent une propagation complète de l'onde dans le domaine. On étudie aussi ce problème d'un point de vue numérique et on montre que pour les cylindres courbés la courbure peut provoquer un blocage de l'onde pour certaines conditions aux bords. / In this thesis we are interested in reaction diffusion equations and their applications in biology and medical sciences. In particular we study the existence or non-existence of propagation phenomena in non homogeneous media through the existence of traveling waves or more generally the existence of transition fronts.First we study a bistable reaction diffusion equation in exterior domain modelling the evolution of the density of a population facing an obstacle. We prove that when the obstacle satisfies some regularity properties and is close to a star shaped or directionally convex domain then the population invades the entire domain. We also investigate the optimal regularity conditions that allow a complete invasion of the population. In a second work, we look at a reaction diffusion equation with forced speed, modelling the evolution of the density of a population facing an unfavourable climate change. We prove that depending on the speed of the climate change the population keeps track with the climate change or goes extinct. We also prove that the population, when it survives, propagates with a constant profile at a constant speed at large time. Lastly we consider a bistable reaction diffusion equation in various cylindrical domains, modelling the evolution of a depolarisation wave in the brain. We prove that this wave is blocked when the domain goes from a thin channel to a cylinder, whose diameter is of order 1 and we give general conditions on the geometry of the domain that allow propagation. We also study this problem numerically and prove that for curved cylinders the curvature can block the wave for particular boundary conditions.

No description available.

The thesis focuses on the qualitative analysis of a general class of SEIRS models in periodic and non-periodic environments. The classical SEIRS model, with standard incidence function, is, first of all, extended to incorporate multiple infectious stages. Using Lyapunov function theory and LaSalle's Invariance Principle, the disease-free equilibrium (DFE) of the resulting SEIⁿRS model is shown to be globally-asymptotically stable whenever the associated reproduction number is less than unity. Furthermore, this model has a unique endemic equilibrium point (EEP), which is shown (using a non-linear Lyapunov function of Goh-Volterra type) to be globally-asymptotically stable for a special case. The SEIⁿRS model is further extended to incorporate arbitrary number of latent stages. A notable feature of the resulting SE^mIⁿRS model is that it uses gamma distribution assumptions for the average waiting times in the latent (m) and infectious (n) stages. Like in the case of the SEIⁿRS model, the SE^mIⁿRS model also has a globally-asymptotically stable DFE when its associated reproduction threshold is less than unity, and it has a unique EEP (which is globally-stable for a special case) when the threshold exceeds unity. The SE^mIⁿRS model is further extended to incorporate the effect of periodicity on the disease transmission dynamics. The resulting non-autonomous SE^mIⁿRS model is shown to have a globally-stable disease-free solution when the associated reproduction ratio is less than unity. Furthermore, the non-autonomous model has at least one positive (non-trivial) periodic solution when the reproduction ratio exceeds unity. It is shown (using persistence theory) that, for the non-autonomous model, the disease will always persist in the population whenever the reproduction ratio is greater than unity. One of the main mathematical contributions of this thesis is that it shows that adding multiple latent and infectious stages, gamma distribution assumptions (for the average waiting times in these stages) and periodicity to the classical SEIRS model (with standard incidence) does not alter the main qualitative dynamics (pertaining to the persistence or elimination of the disease from the population) of the SEIRS model.

The thesis focuses on the qualitative analysis of a general class of SEIRS models in periodic and non-periodic environments. The classical SEIRS model, with standard incidence function, is, first of all, extended to incorporate multiple infectious stages. Using Lyapunov function theory and LaSalle's Invariance Principle, the disease-free equilibrium (DFE) of the resulting SEIⁿRS model is shown to be globally-asymptotically stable whenever the associated reproduction number is less than unity. Furthermore, this model has a unique endemic equilibrium point (EEP), which is shown (using a non-linear Lyapunov function of Goh-Volterra type) to be globally-asymptotically stable for a special case. The SEIⁿRS model is further extended to incorporate arbitrary number of latent stages. A notable feature of the resulting SE^mIⁿRS model is that it uses gamma distribution assumptions for the average waiting times in the latent (m) and infectious (n) stages. Like in the case of the SEIⁿRS model, the SE^mIⁿRS model also has a globally-asymptotically stable DFE when its associated reproduction threshold is less than unity, and it has a unique EEP (which is globally-stable for a special case) when the threshold exceeds unity. The SE^mIⁿRS model is further extended to incorporate the effect of periodicity on the disease transmission dynamics. The resulting non-autonomous SE^mIⁿRS model is shown to have a globally-stable disease-free solution when the associated reproduction ratio is less than unity. Furthermore, the non-autonomous model has at least one positive (non-trivial) periodic solution when the reproduction ratio exceeds unity. It is shown (using persistence theory) that, for the non-autonomous model, the disease will always persist in the population whenever the reproduction ratio is greater than unity. One of the main mathematical contributions of this thesis is that it shows that adding multiple latent and infectious stages, gamma distribution assumptions (for the average waiting times in these stages) and periodicity to the classical SEIRS model (with standard incidence) does not alter the main qualitative dynamics (pertaining to the persistence or elimination of the disease from the population) of the SEIRS model.

Together with the current antibiotic resistance crisis, bacterial persistence appears to play an increasingly important role in the frequent failure of antibiotic treatments. Persister cells are rare bacteria that transiently become drug tolerant, allowing them to survive lethal concentrations of bactericidal antibiotics. Upon antibiotic removal, persister cells are able to resume growth and give rise to a new bacterial population as sensitive to the antibiotic as the original population. Interest in persister cells seriously increased in the past few years as these phenotypic variants were shown to be involved in the recalcitrance of chronic infections, such as tuberculosis and pneumonia and in the well-known biofilm tolerance to antibiotics. Persistence has therefore been extensively studied throughout the last decade, which led to the discovery of large variety of different molecular mechanisms involved in persisters formation. However, the specific physiology of bacterial persisters remains elusive up to now, mainly because of the transient nature and the low frequencies of persister cells in growing bacterial cultures. This work aims to gain a better understanding of the physiology of Escherichia coli persisters by combining population analyses with single-cell observations.In the first part of this thesis, we developed an experimental method allowing for measuring persistence with increased reproducibility. The method was further refined, which allowed us to observe four distinct phases in the ofloxacin time-kill curve, suggesting the existence of a tolerance continuum at the population level at treatment time. Characterization of these four phases notably revealed that the growth rate and the intrinsic antibiotic susceptibility of the strain define the number of surviving cells at the onset of the persistence phase, while persister cells survival mainly relies on active stress responses (SOS and stringent responses in particular).We next investigated the molecular mechanisms underlying the well-known correlation between persistence and the growth rate. Interestingly, we showed that the growth rate determines the number of survival cells at the onset of the persistent phase, whereas it does not affect the death rate of persister cells during antibiotic treatment. Furthermore, slow growth was shown to influence survival to ofloxacin independently of the replication rate, thereby suggesting that target inactivation solely cannot explain this correlation. However, our preliminary data indicate that ppGpp induction upon ofloxacin exposure substantially increases in slow growing bacterial populations, supporting a model in which slow growth would allow bacteria to respond faster to the antibiotic treatment, thereby generating more persisters than fast growing bacterial populations.Finally, both population and single-cell analyses were performed to assess the influence of the SOS response on persistence to ofloxacin. Firstly, population analyses revealed that the SOS response is required for survival of both sensitive and persister cells, but only during recovery, after ofloxacin removal, presumably allowing cells to induce SOS-dependent DNA repair pathways, required to deal with the accumulated ofloxacin-induced DNA lesions. The SOS response therefore appears as a good target for anti-persisters strategies, as shown by the 100-fold decrease in persistence upon co-treatment of a bacterial population with an SOS-inhibitor and ofloxacin. Secondly, single-cell analyses revealed that persister cells sustain similar DNA damages than sensitive cells upon ofloxacin treatment and induce SulA- and SOS-independent filamentation upon antibiotic removal, probably reflecting the presence of remaining cleaved complexes, formed during ofloxacin exposure. Importantly, we showed filamentation to occur in persister cells upon ampicillin treatment as well, thereby suggesting these filaments to be part of a more general survival pathway, which molecular basis remains unknown. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

<p>The only datasets used in my thesis work are from TUDatasets, <a href="https://chrsmrrs.github.io/datasets/">TUDataset | TUD Benchmark datasets (chrsmrrs.github.io)</a>, a collection of public benchmark datasets for graph classification and regression.</p><p><br></p>