2 pp. / Nondormant alfalfa varieties are adapted to mild winter areas in Arizona. An alfalfa variety should be selected based on dormancy class, potential pest problems, university yield trials, and on-farm tests. This publication contains pest resistance ratings and a summary of University of Arizona yield trials for nondormant alfalfa varieties.

2 pp.

2 pp.

Les dormants ferroviaires sont des éléments importants de la structure des chemins de fer. Ils constituent le lien de transfert entre les rails et le sol. Conventionnellement, les dormants nord-américains sont faits avec des madriers de bois. Depuis plusieurs années, différents matériaux ont été utilisés dans le but de trouver un choix alternatif. L’acier, le béton renforcé d’armature d’acier ou bien les matériaux composites ont tous été des matériaux qui ont été proposés dans le passé. Avec le temps, tous ces matériaux se détériorent et doivent être remplacés. L’objectif principal de cette étude est de trouver une solution alternative économique et durable composée de béton et de polymères renforcés de fibres de verre, de carbone ou de basalte (PRFV, PRFC, PRFB). Cette étude comprend deux volets principaux. Le premier volet porte sur les essais expérimentaux de 19 spécimens pour un total de 32 essais. La longueur totale des spécimens testés est de 2590 mm et ceux-ci ont une section transversale ayant une forme trapézoïdale avec une hauteur varient longitudinalement entre 190.5 mm et 241 mm. Ces spécimens sont testés en flexion quatre points aux extrémités, là où l’assise du rail se situe, ainsi qu’au centre. Dans les deux cas, les essais sont faits sous un chargement représentant en un premier temps l’application d’un moment positif et en un deuxième temps d’un moment négatif. Le second volet porte sur la l’analyse des résultats obtenus lors des essais. Dans cette section, le réseau de fissuration, la flèche, la déformation des barres ainsi que la déformation du béton sont analysés plus en détail. Ensuite une comparaison entre les résultats expérimentaux et les prédictions théoriques est effectuée. Cette comparaison traite de la validation des résistances obtenues en fonction des différentes normes nord-américaines ainsi que selon les exigences minimales des lignes directrices établie par l’American Railway Engineering and Maintenance-of-Way Association (AREMA). Les résultats de cette étude profiteront aux compagnies propriétaires de réseau ferroviaire ainsi qu’aux fabricants d’éléments structuraux préfabriqués en béton armé. De plus, cette étude permettra le développement de réseaux ferroviaires plus durables pouvant accueillir des trains se déplaçant à de plus grandes vitesses et pouvant supporter de plus grandes charges lors du transport.

The morphological development of Elberta peach fruit buds was studied in relation to their cold hardiness. Morphological development of peach fruit buds was observed beginning with bud differentiation in mid-summer. Flower initiation was essentially complete by September. Growth was slow in the winter months but increased rapidly as anthesis approached. Photomicrographs were taken to substantiate the discussion . Cold hardiness determinations were made from December until anthesis in April. The hardiness level was greatest during December and remained at a relatively high level until rest ended. Hardiness decreased thereafter. Major losses of hardiness occurred just prior to anthesis.

Populations of federally-listed gopher tortoises (Gopherus polyphemus) are in decline in Mississippi. Soil and forage quality may be linked to their health and recruitment. To gain a better understanding of existing soil and forage quality conditions on areas inhabited by gopher tortoises, I investigated soil chemistry parameters, forage nutrients, and plant community characteristics from 2012 to 2013. These parameters were collected on 7 soil and habitat management treatment types in uplands on public forest lands in south Mississippi. Soil sample analyses indicated that most pH levels in soils were acidic (pH < 5.0) to strongly acidic (pH < 4.5). Greatest soil calcium levels were detected on growing season burn, moderately suitable soil areas, and soil phosphorus levels were greatest on mowed, less suitable soil areas. Greatest levels of nutrients were detected at 0 – 10 cm soil depths. Weak, positive associations were detected between soil pH and soil calcium and magnesium levels, while weak, negative associations were detected between soil pH and soil phosphorus levels. Greater levels of calcium, magnesium, and phosphorus were detected in plants collected in mowed, less suitable soil areas. Cacti, forbs and, legumes were found to have greatest nutrient levels of all the plant growth forms. Moderate, positive associations were detected between soil pH and calcium levels in legumes and vines. Weak, positive associations were detected between soil pH and forage calcium levels in forbs and native grasses. Very weak, positive associations were detected between soil pH and forage phosphorus levels in vines. I found greatest species richness and percent coverage of legumes and forbs on moderately suitable soils that received growing season fire; whereas, greater species richness and percent coverage of native grasses were detected on moderately suitable soil regardless of season of burn. Greatest percent coverage of cacti (puntia sp.) and greatest quantities of above-ground plant biomass were detected on mowed, less suitable soil areas. This information can be valuable to habitat evaluation and management for gopher tortoises.

Variable mortality of Pyrenophora semeniperda--infected Bromus tectorum seeds has been referred to as a "race for survival", stating that seeds that germinate quickly are more likely to escape pathogen-caused mortality. Dormancy status is not the only variable determining outcomes within the Bromus-Pyrenophora pathosystem. Varying temperature and exposure to water may strongly influence germination outcomes of B. tectorum when in the presence of P. semeniperda. Low water potentials characteristic of semi-arid soils are often over-looked in the context of seed pathogens, and are ecologically relevant- especially for plant species that inhabit intermittently dry environments. To adequately characterize the Bromus tectorum-Pyrenophora semeniperda pathosystem, four studies were conducted to address the following questions: (1) do temperature, water potential, and dormancy status influence germination outcomes in the Bromus-Pyrenophora pathosystem, (2) do repeated wetting-drying scenarios influence germination outcomes of infected B. tectorum seeds following dehydration at low water potentials similar to those found in the field (i.e., -4 through -150 MPa), (3) can we accurately characterize the asexual life cycle of P. semeniperda on a dormant B. tectorum seed, determining when infection takes place, and what occurs during disease development in continuously hydrated conditions, and (4) how does disease development of P. semeniperda influence the B. tectorum seed embryo and endosperm. All studies were conducted using dormant and/or non-dormant B. tectorum seeds and an intermediate strain of P. semeniperda. Study one used varying temperatures (5-20°C), and five water potentials (0, -0.5, -1, -1.5, -2 MPa) (achieved using PEG 8000). Inoculated seeds were exposed to low water potentials at various temperatures for 7, 14, 21, or 28 days then re-hydrated for 28 days. In the second study, seeds were incubated at 20°C at four nominal water potentials (-4, -10, -40, or -150 MPa) following 8 or 24 hours of initial hydration. Seeds were dehydrated for 1, 7, 14, or 21 days, then re-hydrated. In study three, inoculated seeds were chemically fixed between days 0 and 21 and viewed with a scanning electron microscope. In the fourth study, infected seeds were frozen with liquid nitrogen following 3, 8, and 14 days of disease development, then cross sectioned longitudinally and laterally prior to chemical fixation. Results indicate that non-dormant seeds escape death by germinating rapidly under favorable conditions, that incubation at low water potentials greatly increases seed mortality, that -10 MPa is near the threshold for full pathogen activity, and at water potentials lower than -40 MPa, P. semeniperda may successfully survive severe dehydration if previous hydration resulting in infection has occurred. SEM images indicate that mycelia penetration occurs within 8-24 hours, and that mycelium may penetrate all opening in the seed (i.e., stomata, cracks). Development of P. semeniperda is shown to cause significant damage to the endosperm and embryo within 8 days. As starch is consumed, the endosperm collapses leaving a hollow middle. The embryo is more resilient, but gradually deforms and deteriorates.

A study of nucleic acid changes influenced by gibberellic acid and chilling treatments in peach seed was performed in an attempt to reach a better understanding of the mechanism involved in breaking seed dormancy. Gibberellic acid and the chilling treatment increased the RNA content. These two treatments which break dormancy also increased RNA, suggesting a similar mechanism involving RNA. Chilled seeds contained more RNA than did the gibberellic acid treated seeds. DNA content remained unchanged regardless of treatment. Dry seed had a greater ribonuclease activity than with soaked seeds. Enzyme changes did not correlate well with the RNA content in gibberellic treated seeds. Deoxyribonuclease activity was higher in dry seed than with soaked seeds. Enzyme activity change did not correlate well with the DNA content. The phosphorus content of the seed in regard to the gibberllic acid and chilling treatments was difficult to evaluate. There were no major relationships established. Phosphorus in the methanol fraction from the chilled seed increased some as the storage period increased.

Storytelling has existed since the beginning of humanity, in every culture. Today, we are still telling stories that are hundreds of years old. Sleeping Beauty, or La belle au bois dormant, is a classic fairy-tale. In the original version by Charles Perrault it is a story in two parts with a morality poem in the end. In this work, the relation between the story and the lessons that can be drawn from it and its final morality are examined. The aim of this work is to find out if the morality confirms or contradicts the story in La belle au bois dormant, and in what way, and secondly if La belle au bois dormant fulfil our expectations of a fairy tale. In order to give a deeper understanding of the key words, fairy-tale, as a genre, and the role of moral in literature two books aimed for literary education in French schools are used. By defining fairy-tale as a genre and the role of moral messages in literature, they can be compared to our story. Furthermore, by using examples from the story and analysing the story and the morality poem of Sleeping Beauty respectively, thus this essay spreads light on the contradicting messages in this fairy-tale. At the end of this work the conclusion is reached that the morality poem is not in any way confirmed by the story and that the two differ in terms of theme, content, and message, and thus La belle au bois dormant differ from traditional fairy tales because its morality does not support the story.

Combating drug resistant malaria has been historically challenging, and remains so today. Recent reports from Southeast Asia show that Plasmodium falciparum is developing resistance to even our best defenses; artemisinin-based therapies. This development threatens to become a significant challenge in controlling malaria infections worldwide, making research into developing and characterizing new antimalarial drugs increasingly important. The purpose of this study was to characterize the resistance potential of novel antimalarial compound JPC-3210 in vitro using P. falciparum clones. JPC-3210 is a new long acting drug with potential to be used in combination with fast-acting drugs like artemisinins to cure drug resistant malaria. In this study several methods were used to characterize the efficacy and resistance potential of JPC-3210. To determine the frequency of resistance generation in P. falciparum clones, parasites were kept under continuous drug pressure for thirty days, at which point drug pressure was removed and cultures were observed for signs of recrudescence. P. falciparum clones also were exposed to increasing levels of intermittent drug pressure that involved 3-4 days of drug exposure followed by a recovery period. The step-wise experiment was conducted over three months with drug pressure being increased step-wise until a maximal concentration of 700 ng/ml of JPC-3210; resistance was measured phenotypically in drug susceptibility assays at multiple time points. Additionally, the ability of JPC-3210 to induce dormant stage parasites, and its effect on dihydroartemisinin (DHA)-induced dormant stages was assessed in both a chloroquine resistant parasite (W2) and in an artemisinin resistant clone (4G). Results showed that the frequency of resistance against JPC-3210 in W2 clones was less when compared to that of atovaquone. The step-wise pulse exposure of JPC-3210 induced resistance in W2 clones, however, resistance proved unstable. Dormant stage parasites were not induced by JPC-3210, even at high concentrations in W2 or 4G clones, furthermore, the effect of JPC-3210 on dormant-induced parasites was found to be dose dependent, yet the drug did not kill DHA-induced dormant rings. JPC-3210 appears to be a good drug to use in combination with other antimalarial compounds for treatment of P. falciparum, but further research is needed. Future studies to assess the field performance of new antimalarial compounds by investigating resistance and dormancy profiles in vitro, and thereby maximizing out understanding of such drugs and their optimal implementation, are of the utmost importance.