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Nutrient profiles of distillers grains are primarily affected by the type of grain used for ethanol production, but the feeding value of triticale-based dry distillers grains plus solubles (TDDGS) has not been extensively studied. The first study showed that, compared to 20% corn- or wheat-based distillers grains diets, 20% TDDGS diet increased cis-9 trans-11 linoleic acid concentration in carcass fat without affecting growth performance of lambs. In the second study, lamb growth performance was not affected by the addition of up to 60% TDDGS in the diet, but the risk of urinary calculi increased at higher inclusion levels. Lambs fed 20% TDDGS had higher cold carcass weights and grade rules than lambs fed 40 or 60% TDDGS. Increasing TDDGS decreased diet digestibility, and increased nitrogen and phosphorus excretion. In conclusion, TDDGS can be used in diets for growing ruminants, and its utilization efficiency may be optimized at 20% dietary inclusion. / Animal Science

Balaustium medicagoense (Acari: Erythraeidae) and Bryobia spp. (Acari: Tetranychidae) have recently been identified as emerging pests of winter crops and pastures by the Australian grains industry. The relative importance of these mites and damage caused by them in Australia has markedly increased in the last decade, and pest reports indicate extensive damage to a variety of winter grain crops and pastures. Furthermore, pest reports suggest that these mites have been difficult to control in the field, with some pesticides described as being ineffective. Despite this, there is very little information about the biology and control of these species, making it difficult to devise effective and sustainable management strategies. This thesis addresses some of these concerns by investigating various aspects of the biology, ecology and genetics of these mites in broad acre agriculture in southern Australia. / Laboratory bioassays were undertaken to examine the response of Ba. medicagoense and B. sp. I (along with the redlegged earth mite (Halotydeus destructor) as a point of reference) to several currently registered pesticides against earth mites. Balaustium medicagoense and B. sp. I generally had a much greater level of tolerance to the pesticides tested than H. destructor. These mites therefore have a high natural tolerance to currently registered pesticides and may prove difficult to control in the field. These findings suggest other strategies that are not reliant on chemicals should be considered for control of Ba. medicagoense and B. sp. I. / The effects of different crop plants on the survival and reproduction of Ba. medicagoense and Bryobia spp. (B. sp. VIII and B. sp. IX) and the plant damage caused by these mites were investigated under shade-house conditions. In addition information from field surveys and pest report bulletins was collated to test for outbreak patterns. The findings showed that these mites were polyphagous, attacking a variety of agriculturally important plants as well as numerous weeds within southern Australia. Therefore, these mites have the potential to be important pests on several winter grain crops and pasture, but there are important differences in host responses that might assist in management strategies such as targeted crop rotations and weed management. / The distribution, life cycle, seasonal abundance patterns and the pest status of Ba. medicagoense and Bryobia spp. were examined in southern Australia. Both mites are widely distributed throughout Mediterranean-type climate areas within southern Australia. Balaustium medicagoense has two generations per year and was active from March until December, with a likely diapause period in summer. There were differences in the seasonal abundance and life cycle of two species of Bryobia (B. sp. IX and B. sp. I). Bryobia sp. IX had two generations per year, was active from March until December, and was likely to be in diapause over the summer months. Bryobia sp. I did not have a diapause stage, was active year round and had approximately four generations per year. Seasonal abundance patterns of Ba. medicagoense and B. sp. IX overlapped with those of the major pest mite species H. destructor and Penthaleus major. A survey of pest outbreaks and chemical control failures showed that while H. destructor and the Penthaleus species remained important pests, outbreaks and control failures involving Ba. medicagoense and Bryobia spp. had increased over the last decade. / The species/strain status of Balaustium and Bryobia mites from broad acre environments was examined in southern Australia using a combination of mitochondrial and nuclear DNA sequence data. In addition, the reproductive mode and genetic diversity of Ba. medicagoense was examined using the amplified fragment length polymorphism (AFLP) method. Findings showed that Ba. medicagoense is the only species present in grain crops, pastures and roadsides within southern Australia, and at least seven species of Bryobia mites are present. The AFLP data revealed that Ba. medicagoense reproduces asexually and that genetic diversity was low with only 10 genotypes found from 16 populations. / Overall, the data presented in this thesis helps to explain why Ba. medicagoense and Bryobia spp. are emerging pests and points to ways in which these mites may be controlled in the future. The results show that these mites are difficult to control with currently registered pesticides, have a widespread distribution, can potentially increase in abundance rapidly under favourable conditions and persist across a wider range of seasonal conditions than other major pest earth mites. However, there are differences in pesticide susceptibilities and plant host responses that have the potential to be exploited when developing targeted control options for these pest mites.

Thesis--Universidade Federal do Rio Grande do Sul. / Bibliography: leaves 143-146.

The aim of this thesis is to comprehensively analyse presolar silicon carbide (SiC) grains from several primitive meteorites in order to investigate their complicated history. During their residence in the interstellar medium, presolar grains are predicted to be affected by many processes which may modify their original elemental and isotopic composition. Presolar SiC grains from three acid residues and two polished meteorite sections were analysed for their carbon, nitrogen and silicon isotope ratios with high spatial resolution, in order to compare the distribution of 14N/15N ratios compared to those found in the literature. As a result of this work, isotopic fractionation effects caused by the distortion of the electric field around the grain topography were identified. These effects have the potential to cause differential transmission of atomic and molecular secondary ions, particularly when small slits and apertures are selected during NanoSIMS analyses. The measured 14N/15N ratios of the presolar SiC grains analysed in this work match well with existing literature data, although many grains cluster at relatively low 14N/15N values. These low ratios do not appear to be the result of either terrestrial contamination or isotopic dilution, and may instead represent real differences between the SiC grain populations of different meteorites. The majority of mainstream SiC grains analysed in this work lie on a slope with a gradient of ~1.3 on a Si 3-isotope plot, in agreement with literature data. SiC grains from the JAMM and JA-MM2 acid residues appear to lie on shallower slopes, although these samples show significant scatter in the data. Neither terrestrial contamination nor isotopic dilution can explain the apparent fractionation of silicon isotopes in these samples. It is possible that these ratios may represent a difference in the Si ratios of grain populations of different meteorites, although fractionation during the sample preparation phase cannot be excluded. Ten presolar SiC grains from the KJG and JA-MM2 acid residues are comprehensively analysed for their trace element compositions using Time-of-Flight Secondary Ion Mass Spectrometry. The majority of analyses are significantly affected by the proximity of neighbouring grains, leading to high background counts which prevent the reliable determination of elemental abundances for many elements. Depth profiles of several elements are determined for two grains from the KJG residue. Each of the measured elements displays approximately homogeneous profiles through the grains, with abundances in agreement with existing literature data. The uniform depth profiles may represent formation in a stellar envelope with a stable composition, although homogenisation by secondary alteration processes cannot be ruled out.

Dans cette thèse, nous travaillons sur les questions d'existence, puis d'absence de percolation de graphes orientés stationnaires dans l'espace euclidien. Les sommets de ces graphes sont distribués par un processus ponctuel de Poisson, et chaque sommet est connecté vers un unique autre sommet par une arête orientée. On parle alors de graphe orienté 'outdegree-one'. La règle permettant de construire l'ensemble des arêtes définie le graphe. Le premier résultat de la thèse fournit une condition suffisante pour qu'un graphe ne contienne pas de composantes connexes infinies. Un corollaire important de ce premier résultat affirme que le graphe orienté défini par une dynamique de segments grandissants décrites par D. Daley, G. Last et S. Ebert ne percole pas. Ce modèle défini à partir de segments poussant à vitesse constante dans le plan est un exemple de dynamique germes grains. Le second chapitre de la thèse propose une définition générale du modèle germes grains dans le plan et donne une condition suffisante pour qu'un modèle germes grains fixé puisse se caractériser par un graphe orienté "outdegree-one". Ce dernier résultat nous permet d'assurer l'existence de plusieurs graphe géométrique tout à fait naturel est riche en application. Le dernier résultat de la thèse consiste en l'absence de percolation d'une dynamique de segment grandissant qui généralise le modèle préalablement cité et dont l'existence découle de notre précédent résultat. / In this thesis, we investigate the existence and the absence of percolation for a large family of random graphs. We precisely study the oriented outdegree-one graphs based on a Poisson point process in $\mathbf{R}^{d}$. On the random pattern of points, each vertex is connected to its unique "neighbour" according to a fixed connection rule. This rule is translation-invariant and could also include a random part. Many natural simple dynamics can be described by an outdegree-one graph: the classical walk to the nearest neighbour on the graph defined by the hard sphere Lilypond model, etc.The first result of the thesis establishes sufficient conditions which guarantee the almost sure absence of infinite connected component in the graph. Precisely, each Poisson outdegree-one graph satisfying two precise assumptions does not percolate. The proof uses the mass transport principle, and an important result of stochastic domination. The most important corollary of this theorem is the absence of percolation of the line segment model with unit speed which has been conjectured in 2014 by D. Daley, S. Ebert and G. Last.The line segment model with random speed is well defined (as a stopped germs grains model) if the random velocity has an order $4$ moment. In the last chapter, we proved that the existence of an order $s$ exponential moment (with $s>1$) ensures the almost sure absence of percolation of the configuration of stopped segments. One of the key point of this result is the existence of a sufficiently small time $\mathbf{T}$ such that, before the time $\mathbf{T}$, any quick segments grows inside a boolean model which does not percolate. This argument should be used for different kinds of germs grains dynamics.

Pour voies ferrées à grandes vitesses (LGV, Lignes à Grande Vitesse), la durabilité des performances du ballast de chemin de fer n’est pas aussi importante qu’attendu. Le comportement mécanique de cette couche granulaire mince dépend fortement de la forme, la taille et la minéralogie des grains. Sur les LGV, les grains s’usent plus vite qu’attendu, essentiellement à cause de l’accumulation des opérations de maintenance appelées bourrage. Une conséquence à cela est un renouvellement complet du ballast avec une fréquence largement supérieure à ce qui était initialement prévu à la création de ces lignes.Soumis à des contraintes dynamiques combinées (trafic ferroviaire et des opérations de bourrage), les grains de ballast se dégradent par fragmentation et par attrition aux contacts. Les conséquences directes de cette dégradation progressive sont l’évolution de la taille et de la forme des grains. La courbe granulométrique est alors translatée vers les petits éléments, avec une présence notable de particules très fines résultant de l’usure des grains. De plus, l’angularité des grains est progressivement diminuée. Au-delà d’un certain temps, le cumul de dégradation se traduit par une chute des performances mécaniques du ballast. Le ballast ne remplit plus efficacement ses fonctions. La résistance latérale de la voie est réduite, limitant ainsi la répartition des contraintes sur la plateforme et l’ancrage des traverses. La présence excessive de fines rend le bourrage inefficace et diminue la perméabilité de la voie. Par conséquent, pour trouver des solutions optimales pour prolonger la durée de vie du ballast, il est nécessaire d’abord de bien comprendre les origines et mécanismes menant à l’usure des grains, pour finalement construire un modèle prédictif de dégradation.La dégradation des interfaces au contact génère de particules fines. La quantité de fines produite, laquelle dépend des conditions de chargement, est classiquement prédite par l’équation d’Archard. Ce modèle part du principe que le volume d’usure généré est proportionnel à la force normale et au déplacement relatif entre les surfaces en contact. La simulation numérique par éléments discrets (NSCD) d’une portion de voie de chemin de fer soumis à un chargement cyclique est un outil nécessaire pour réaliser la transition entre l’échelle de la voie et l’échelle du contact, fournissant les informations sur le ballast en tant que couche granulaire, depuis son comportement global jusqu’aux forces de contact et les déplacements relatifs entre les grains. Les contacts montrant un grand potentiel de génération de fines (selon le modèle d’Archard) sont identifiés et reproduits expérimentalement avec des essais de cisaillement entre deux grains. Parallèlement, l’essai d’attrition Micro-Deval est utilisé pour relier les résultats numériques et expérimentaux, et ainsi valider le modèle d’Archard, et pour suivre l’évolution de la forme des grains avec l’aide des scans d’un échantillon de grains par tomographie RX à différents états d’usure. Les deux campagnes d’essais montrent la faiblesse des aspérités les plus aiguisées, dont spécialement celles sur les arêtes et sommets.Un modèle prédictif d’usure en deux phases est donc proposé. La première phase décrit une usure rapide due aux fortes contraintes normales à l’interface de contact, et la deuxième phase décrit un taux d’usure plus modéré. Une contrainte seuil permet d’identifier clairement le passage d’une phase à une autre. Sur la base des déplacements relatifs intergranulaires observés dans la simulation numérique discrète, ce modèle est appliqué pour chaque contact dont l’histoire de chargement est variable. Une estimation de la courbe de génération de fines dans la voie est ainsi proposée. / After some years of high-speed lines in France (HSL), ballast has proven not to be resistant enough. The performance of ballast, as a thin layer of coarse grains, strongly depends on the shape, size and mineralogical nature of the grains composing it. However, in HSL, grains wear faster than expected due to the traffic of trains at high speeds and the accumulation of maintenance operations (tamping). Ballast replacement has therefore been required much before than its originally expected lifespan.Under the dynamic stresses imposed by the circulation of trains and tamping operations, ballast is gradually worn by fragmentation of grains and attrition at the contacts. The direct consequence of this degradation is the evolution of grain size and shape: the grading curve is shifted towards small and fine particles and the grains progressively lose their angularity. Eventually, the cumulated wear will no longer allow ballast to perform properly: the shear resistance of the layer is reduced limiting both the anchorage of sleepers and the distribution of loads to the platform. In addition, the presence in excess of fine particles renders tamping ineffective (fast evolution of track defaults) and reduces the permeability of the track. Thus, in order to search for optimized solutions for prolonging ballast lifespan, it is crucial to first understand the origins and mechanisms leading to ballast degradation when it is subjected to complex loading, for building a predictive model of ballast wear.The degradation of contact interfaces generates fine particles. The associated mass flux, which depends on the loading conditions, has been classically predicted by Archard equation. The model assumes that the generated volume of wear is proportional to the normal force and the relative displacement between the surfaces. Therefore, it is crucial to quantify the forces at the contact scale and the relative displacements between ballast grains in sliding contact. Discrete elements simulations by NSCD are used as a tool for performing a change in scale from the track scale to the contact scale, giving information of ballast as a granular layer, from its global behaviour down to the contact forces and relative displacements between grains. Contacts with a higher potential of generating fine particles (according to Archard model) are then identified and reproduced experimentally by two-grain shearing tests. In parallel, the Micro-Deval standard attrition test is used as a link between numerical and experimental results to validate Archard model, and to study the evolution of grain morphology by scanning a sample of grains using X-ray tomography at different stages of the test. Both experimental campaigns show the weakness of sharp asperities, especially on edges and vertexes.A model in two phases is proposed, accounting for a first phase of fast and aggressive degradation due to the high stress at the contact interface and a more stable second phase with a lower wear rate. A critical stress is identified as a threshold between phases. This model is then applied at each individual contact on the numerical simulations, resulting in a first approach of the production curve of fine particles within the track.

<p> Metagreywackes of the Goldenville Formation, Nova Scotia, possess a well developed penetrative cleavage. Measurement of strain, based on quartz grain shape, indicates that much of the strain has been achieved by pressure solution of detrital quartz grains. Strain ratios in the system range from X/Z = 3.8 in cleavage zones, through 2.0 in intermediate areas, to 1.6 in lithons. The volume lost from cleavage zones ranges from 60 to 70 percent, while loss of volume to the system as a whole is 40 percent or greater. Strain due to plastic deformation is minimal, relative to the strain due to volume loss. The strain within the system is not homogeneous on a centimeter scale, but rather range from low values in mid-lithon zones to much higher values in cleavage zones. Lithon and intermediate areas are representative of the deformation history of the cleavage.</p> / Thesis / Bachelor of Science (BSc)

The objective of this study was to evaluate the impact of maturity at harvest and dietary inclusion rate of triticale silage on the production performance and nutrient utilization of lactating dairy cows. The hypothesis was that the production performance of lactating dairy cows would increase when consuming triticale harvested and ensiled at the boot stage of maturity (BS), as compared to consuming triticale harvested and ensiled at the soft-dough stage of maturity (SDS), and that the difference would be greater in high-forage diets. A single field of triticale was planted, and harvested at the BS or SDS of maturity, and the harvested forage was ensiled in separate bunker silos. Eight primiparous and 16 multiparous Holstein cows were assigned to 1 of 4 diets in a replicated 4 × 4 Latin square design with 21-d periods. Cows were fed once daily (10:00 a.m.) using a Calan gate system (American Calan Inc., Northwood, NH). Diets included BS or SDS triticale silage with dietary forage inclusion of 54% (high-forage; HF) or 36% (low-forage; LF). Cows consuming diets containing BS silage produced more milk per day than cows consuming diets containing SDS silage. This response was observed when feeding both LF and HF diets. The maturity of the forage (BS vs. SDS) did not affect the apparent total tract digestibility of neutral detergent fiber (NDF) or the yield of energy-corrected milk. Cows consuming diets containing BS silage yielded more milk protein and lactose per day than cows consuming diets containing SDS silage, and we also observed this response when feeding both LF and HF diets. When fed the LF diets, cows had a higher apparent total-tract digestibility on CP and NDF, whereas apparent total-tract starch digestibility was higher in cows fed HF diets. Cows consuming LF diets exhibited higher levels of de novo fatty acid synthesis compared to those on HF diets. Feeding LF diets yielded more C14:1, C18:1 trans-9, and unknown fatty acids, while C16:0, C18:1 trans-10, CLA cis-9, trans-11, and CLA trans-10, cis-12 fatty acids yielded more in cows fed with SDS diets. Notably, CLA cis-9, trans-11, and CLA trans-10, cis-12 fatty acids were highest in SDS diets. Additionally, stearic fatty acid (C18:0) concentrations increased in HF diets and SDS silage. In conclusion, the study found that triticale maturity at harvest minimally affects dairy cow performance, with consistent milk production across harvest stages. While nutrient variations were observed, the conclusion emphasizes the importance of considering not only forage quality but also agronomic management and planting schedules for subsequent crops when deciding on harvest timing. / Master of Science / Cool-season or winter annual grasses, also known as small grain grasses, can be cultivated as cover crops to protect or improve the quality of the soil when the warm-season primary crop (e.g., corn) is not growing. These crops are grown during intervals between regular crop production periods. In the context of cover cropping in the United States, small grains are planted during the fall and winter seasons. One of these small grain crops is triticale, a hybrid resulting from the crossbreeding of wheat and rye. Whole plant triticale is ideal for preservation by ensiling due to its high level of water-soluble carbohydrates, low buffering capacity, and easily controllable moisture content. The objectives of this study were to evaluate the impact of harvesting maturity and dietary inclusion rate of whole plant triticale silage on milk production performance and nutrient utilization of lactating dairy cows. The hypothesis was that the production performance of lactating dairy cows would increase when consuming triticale harvested and ensiled at the boot stage of maturity (BS), as compared to consuming triticale harvested and ensiled at the soft-dough stage of maturity (SDS), which is more advanced in maturity. A single field of triticale was planted, harvested at either BS or SDS and ensiled in separate bunker silos. Twenty-four Holstein cows were grouped by days in milk and daily milk production in groups of 4 cows each, and each group was assigned to one of four experimental diets. Regardless of inclusion rate, cows consuming BS diets yielded more milk, milk protein, and lactose than did cows on SDS diets and for milk yield, we observed this response when feeding both LF and HF diets. The maturity at harvest did not affect dry matter, crude protein, neutral detergent fiber, or starch digestibility of the diets. Crude protein and neutral detergent fiber digestibility were higher in cows consuming low-forage diets than in cows consuming high-forage diets, whereas starch apparent total-tract digestibility was higher in cows fed HF diets. In conclusion, the study found that triticale maturity at harvest minimally affects dairy cow performance, with consistent milk production across harvest stages. While nutrient variations were observed, the conclusion emphasizes the importance of considering not only forage quality but also agronomic management and planting schedules for subsequent crops when deciding on harvest timing.

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