Nanogram amounts of salicylic acid produced by the rhizobacterium Pseudomonas aeruginosa 7NSK2 activate the systemic acquired resistance pathway in bean

Root colonization by specific nonpathogenic bacteria can induce a systemic resistance in plants to pathogen infections. In bean, this kind of systemic resistance can be induced by the rhizobacterium Pseudomonas aeruginosa 7NSK2 and depends on the production of salicylic acid by this strain. In a model with plants grown in perlite we demonstrated that Pseudomonas aeruginosa 7NSK2-induced resistance is equivalent to the inclusion of 1 nM salicylic acid in the nutrient solution and used the latter treatment to analyze the molecular basis of this phenomenon. Hydroponic feeding of 1 nM salicylic acid solutions induced phenylalanine ammonia-lyase activity in roots and increased free salicylic acid levels in leaves. Because pathogen-induced systemic acquired resistance involves similar changes it was concluded that 7NSK2-induced resistance is mediated by the systemic acquired resistance pathway. This conclusion was validated by analysis of phenylalanine ammonia-lyase activity in roots and of salicylic acid levels in leaves of soil-grown plants treated with Pseudomonas aeruginosa. The induction of systemic acquired resistance by nanogram amounts of salicylic acid is discussed with respect to long-distance signaling in systemic acquired resistance

Intrusion and extrusion of water in hydrophobic mesopores

We present experimental and theoretical results on intrusion-extrusion cycles of water in hydrophobic mesoporous materials, characterized by independent cylindrical pores. The intrusion, which takes place above the bulk saturation pressure, can be well described using a macroscopic capillary model. Once the material is saturated with water, extrusion takes place upon reduction of the externally applied pressure; Our results for the extrusion pressure can only be understood by assuming that the limiting extrusion mechanism is the nucleation of a vapour bubble inside the pores. A comparison of calculated and experimental nucleation pressures shows that a proper inclusion of line tension effects is necessary to account for the observed values of nucleation barriers. Negative line tensions of order $10^{-11} \mathrm{J.m}^{-1}$ are found for our system, in reasonable agreement with other experimental estimates of this quantity

Comportement des fissures de fatigue dans un champ de contraintes résiduelles de tension

RÉSUMÉ Ce mémoire présente une étude expérimentale et numérique du comportement d'une fissure se propageant sous l'influence d'un champ de contraintes résiduelles de tension. L'étude comporte deux objectifs principaux. La mesure et le calcul d'un champ de contraintes résiduelles produit par le soudage. La quantification de l'effet du champ de contraintes résiduelles (CR) sur la vitesse de propagation des fissures de fatigue. Cette étude estmotivée par la problématique de fissuration observée dans certaines turbines Francis exploitées par Hydro-Québec. Il existe une incertitude reliée à l'influence qu'a un champ de contraintes résiduelles sur la vitesse de propagation des fissures dans les assemblages mécano-soudés. Les articles disponibles dans la littérature traitant du sujet n'ont pas démontré hors de tous doutes l'influence des contraintes résiduelles sur le comportement en fatigue-propagation. En effet, les conclusions proposées sont tirées de résultats pour lesquels l’effet de la microstructure, modifiée lors de l’introduction des contraintes résiduelles, se superpose potentiellement à l’effet des contraintes résiduelles Il devient donc difficile d’isoler l'influence des contraintes résiduelles pour confirmer que leur effet est équivalent à la simple superposition d’une contrainte monotone à la sollicitation cyclique. Dans le but d’isoler l’effet des contraintes résiduelles, une nouvelle géométrie d'éprouvette a été développée à l'Institut de Recherche d'Hydro-Québec (IREQ). Cette éprouvette originale, nommée CT-RES, permet d'étudier la propagation des fissures sous l'influence d'un champ de contraintes résiduelles dans une microstructure homogène. De plus, elle représente mieux l'état de contrainte d'une roue d'eau assemblée par rapport aux éprouvettes de laboratoires utilisées pour caractériser le comportement d'un matériau en fatigue-propagation. En effet, l'éprouvette CT-RES est un assemblage mécano-soudé permettant de reproduite le bridage d'une aube soudée à la ceinture et à la couronne. Un médaillon représentant l'aube est inséré puis soudé dans un cadre rigide. Le bridage est obtenu par l'opposition du cadre au retrait thermique de la soudure. Cette configuration n'est pas retrouvée dans les éprouvettes de laboratoire normalisées utilisées dans la littérature. Suite à la fabrication de l'éprouvette CT-RES, le champ de contraintes résiduelles a été mesuré à l'aide de la méthode du contour. Cette méthode étant destructive, deux éprouvettes ont été fabriquées à l'aide du bras robotisé Scompi®. La première éprouvette a été utilisée pour mesurer le champ de contraintes résiduelles.----------ABSTRACT This master thesis presents an experimental and numerical study concerning the behaviour of a propagating crack under the influence of a residual stress field in tension. The study is composed of two main objectives: 1) The measurement and assesment of a welding residual stress field and 2) The evaluation of the residual stress field influence on the fatigue crack growth rate (FCGR). This study is motivated by the cracking problem observed in some Francis turbines operated by Hydro-Québec. There is an uncertainty related to the influence of a residual stress field on FCGR in welded assemblies. Numerous papers related to the subject have not demonstrated beyond all doubt the influence of residual stress field on FCGR. Indeed, the proposed conclusions are drawn from the results for suggesting that the effect of microstructure alteration during the introduction of residual stresses, is potentially superimposed on the effect of residual stresses. It is therefore becomes difficult to isolate the influence of residual stresses to assess their equivalence to the simple superposition of a monotonic load to cyclic loading. In order to isolate the influence of residual stresses, a novel specimen geometry was developed at the Institut de Recherche d'Hydro-Québec (IREQ). This original specimen, called CT-RES, allows the study of crack propagation under the influence of a residual stress field in a homogeneous microstructure. Moreover, it represents more accurately the stress state of a water wheel assembly, relative to laboratory test specimens used to characterize the fatigue behaviour of materials. Indeed, the CT-RES specimen is a welded assembly that reproduced the clamping effect of a welded blade to the belt and crown. A medallion, that represents the blade, is inserted and welded into a rigid frame. The clamping effect is obtained by the opposition of the frame to the heat shrinkage of the weld. This configuration is not found in standardized laboratory test specimens used in the literature. Following the fabrication of the CT-RES specimen, the residual stress field was measured using the contour method. This method being destructive, two specimens were fabricated using the Scompi® robotic arm. The first specimen was used to measure the residual stress field. The contour method revealed that the stress componen

Micro-scale flow cytometry-based and biochemical analysis of lipid signaling in primary B cell subpopulations

B cell subpopulations in the spleen have been extensively characterized phenotypically; however, biochemical properties of these cell populations following B cell antigen receptor engagement have not been fully determined due to technical difficulties and limiting cell numbers. We therefore employed mini-scale protocols to assess lipid signaling, particularly that of diacylglycerol and inositol trisphosphate, with as few as 0.5x106 purified early (T1) and late (T2) transitional B cells. Additionally, utilizing flow cytometric techniques, we determined levels of phosphatidylinositol bisphosphate and calcium mobilization in T1 and T2 cells, as well as mature follicular and marginal zone B cells using less than 1x106 primary B cells. Thus, these biochemical and flow cytometric methodologies can be used to analyse signal-induced changes in phosphatidylinositol bisphosphate levels, diacylglycerol and inositol triphosphate production and calcium in each B cell population

Localization and expression of EDS5H a homologue of the SA transporter EDS5

An important signal transduction pathway in plant defence depends on the accumulation of salicylic acid (SA). SA is produced in chloroplasts and the multidrug and toxin extrusion transporter ENHANCED DISEASE SUSCEPTIBILITY5 (EDS5; At4g39030) is necessary for the accumulation of SA after pathogen and abiotic stress. EDS5 is localized at the chloroplast and functions in transporting SA from the chloroplast to the cytoplasm. EDS5 has a homologue called EDS5H (EDS5 HOMOLOGUE; At2g21340) but its relationship to EDS5 has not been described and its function is not known. Results: EDS5H exhibits about 72 % similarity and 59 % identity to EDS5. In contrast to EDS5 that is induced after pathogen inoculation, EDS5H was constitutively expressed in all green tissues, independently of pathogen infection. Both transporters are located at the envelope of the chloroplast, the compartment of SA biosynthesis. EDS5H is not involved with the accumulation of SA after inoculation with a pathogen or exposure to UV stress. A phylogenetic analysis supports the hypothesis that EDS5H may be an H+/organic acid antiporter like EDS5. Conclusions: The data based on genetic and molecular studies indicate that EDS5H despite its homology to EDS5 does not contribute to pathogen-induced SA accumulation like EDS5. EDS5H most likely transports related substances such as for example phenolic acids, but unlikely SA

Genetic evidence that expression of NahG modifies defence pathways independent of salicylic acid biosynthesis in the Arabidopsis–Pseudomonas syringae pv. tomato interaction

The salicylic acid (SA)-induction deficient (sid) mutants of Arabidopsis, eds5 and sid2 accumulate normal amounts of camalexin after inoculation with Pseudomonas syringae pv. tomato (Pst), while transgenic NahG plants expressing an SA hydroxylase that degrades SA have reduced levels of camalexin and exhibit a higher susceptibility to different pathogens compared to the sid mutants. SID2 encodes an isochorismate synthase necessary for the synthesis of SA. NahG was shown to act epistatically to the sid mutant phenotype regarding accumulation of camalexin after inoculation with Pst in eds5NahG and sid2NahG plants. The effect of the pad4 mutation on the sid mutant phenotype was furthermore tested in eds5pad4 and sid2pad4 double mutants, and it was demonstrated that PAD4 acts epistatically to EDS5 and SID2 regarding the production of camalexin after inoculation with Pst. NahG plants and pad4 mutants were also found to produce less ethylene (ET) after infection with Pst in comparison to the wild type (WT) and sid mutants. Both PAD4 and NahG acted epistatically to SID regarding the Pst-dependent production of ET that was found to be necessary for the accumulation of camalexin. Early production of jasmonic acid (JA) 12 h after inoculation with Pst/avrRpt2 was absent in all plants expressing NahG compared to the other mutants tested here. These genetic studies unravel pleiotropic changes in defence signalling of NahG plants that are unlikely to result from their low SA content. This adds unexpected difficulties in the interpretation of earlier findings based solely on NahG plants

Épigraphie religieuse et communautés civiques au Haut-Empire : la délimitation du territoire de la ciuitas Aeduorum aux IIe et IIIe siècles

National audienceSince the 19th century, many proposals have been made regarding the boundaries of the territory of the civitas Aeduorum. Although there is general agreement on many geographic sectors, there are still major discrepancies of opinion, principally in the regions of Autissiodurum / Auxerre and Alesia. The religious epigraphy of the Early Empire, in particular the use of a specific formulary, seems to demonstrate a single religious (and political) community in these regions, which would thus have all belonged to the civitas Aeduorum in the 2nd and 3rd centuries.La délimitation du territoire de la ciuitas Aeduorum a fait l’objet de nombreuses propositions depuis le XIXe siècle. Si l’appartenance de beaucoup de secteurs géographiques fait consensus, on note des divergences notables, principalement dans les régions d’Autissiodurum / Auxerre et Alesia. L’épigraphie religieuse du Haut-Empire - et particulièrement l’emploi d’un formulaire spécifique - semble démontrer une communauté religieuse (et politique) dans ces régions, qui appartiendraient donc toutes à la cité des Éduens aux IIe et IIIe s. ap

El sistema de pago de obligaciones tributarias (SPOT) y su impacto en la libre disposición del efectivo en la empresa Minera Andina For S.A.C., Trujillo 2016

RESUMEN El principal objetivo de esta tesis es medir el impacto que tiene la aplicación del Sistema de Pago de Obligaciones Tributarias en la libre disponibilidad del efectivo de la empresa Minera Andina For S.A.C. de la ciudad de Trujillo, a través de una investigación ex post facto. La hipótesis planteada es que “El SPOT impacta significativamente en la libre disposición del efectivo de la empresa Minera Andina For S.A.C restringiendo el uso del mismo, según las decisiones de la gerencia para el normal desarrollo de sus actividades comerciales afectando el cumplimiento de sus obligaciones con terceros”. Se utilizaron como técnicas de recolección de datos la entrevista y el análisis documentario y para ello se realizaron los procedimientos de detalle de los depósitos y usos de la cuenta de detracciones, análisis a sus obligaciones financieras y comerciales. Se mostró estos datos en tablas y gráficos para analizar y demostrar el poco uso del fondo de detracciones para el pago de impuestos y cuan alto era el saldo acumulado mensualmente en esta cuenta. Asimismo, se contrastó estos resultados con tesis anteriores y opiniones de profesionales en ciencias contables, donde se llega a ratificar la hipótesis. Por último, se realizó una entrevista al gerente de la empresa, para conocer su opinión acerca de las detracciones y la liberación de fondos. Todo esto demuestra que el SPOT tiene un impacto negativo para la empresa Minera Andina For S.A.C. económica y financieramente, negándole así la oportunidad de reinvertir su capital de trabajo y hacer frente a otros pagos comerciales, obligándola de esta manera a recurrir a soluciones financieras, como el caso del préstamo.ABSTRACT The main objective of this thesis is to measure the impact of the application of the Tax Obligation Payment System on the free availability of cash from the company Minera Andina For S.A.C. Of the city of Trujillo, through an ex post facto investigation. The hypothesis is that "SPOT significantly impacts on the free disposition of the cash of the company Minera Andina For SAC restricting the use of it, according to the decisions of the management for the normal development of its commercial activities affecting the fulfillment of its obligations with third parties". The interviews and documentary analysis were used as data collection techniques and for this the procedures of detail of the deposits and uses of the detractions account, analysis to their financial and commercial obligations were performed. These data were shown in tables and graphs to analyze and demonstrate the low usage of the detractions fund for the payment of taxes and how high was the balance accumulated monthly in this account. Likewise, these results were compared with previous theses and opinions of professionals in accounting sciences, where the hypothesis is confirmed. Finally, an interview was conducted with the company manager, to know his opinion about the drawdowns and the release of funds. All this shows that the SPOT has a negative impact for the company Minera Andina For S.A.C. Economically and financially, thereby denying him the opportunity to reinvest his working capital and to face other commercial payments, forcing him to resort to financial solutions, such as the loan