The use of techniques for determining the productive capacity of a forest site depends on its sensitivity to evaluate or to predict the interaction between the genetic factors of the species and the environment (climate, soil, physiography). This work was developed in the southern part of Rio Grande do Sul state and aimed to evaluate the influence of soil properties in different soil classes, with the production capacity by the dominant height (h100) for Eucalyptus saligna (clone 32864) and seminal plantations of Eucalyptus dunnii. Thus, we selected 16 inventory plots based on genetic material and dendrometric variables as the dominant height (h100), mean annual increment (MAI), volume of wood with bark (m3/ ha-1) designed for seven years. Form these 16 plots, nine plots were E. dunnii and seven plots were E. Saligna. In each selected site trenches were opened to classify the soil, to collect soil samples for chemical (pH, MO, Ca, Mg, Al, P, S, K, Zn, Cu, B, CTC,ph7, V) and physical analysis ( particle size, particle density and soil porosity, macro and microporosity, soil water retention curve , saturated hydraulic conductivity) and to collect litter. Profiles/plots showed variations in soil classes, site index, source material, morphological, chemical and physical soil characteristics and amount of litter. We analyzed four classes of representative soils of the study region: Argissolos (PVe, PVd, PBACd, PBACe, PAd), Neossolos (RRd), Luvissolos (TCo) and Cambissolos (CXbd). The dominant height (h100) showed a minimum height of 22.9 m ( Profile 13 - RRd) and maximum height of 29.3 m (Profile 10-TCo) for E. dunnii and for the clone E. saligna the IS showed a minimum height of 22.4 m (Profile 11- PAd) and maximum of 28.7 m (Profile 16-PVe). The statistical analysis between dominant height (h100) and the physical, chemical and morphological soil characteristics was performed by the use of multiple regression analysis, which aimed to verify the significance of the input variables to determine the dominant height. The equations that best correlated the dominant height to soil attributes were derived from the layers 10-20 cm and 60-80 cm when were considered both genetic materials. However, when genetic materials were evaluated separately the equations that best correlated the dominant height to soil attributes were derived from the layers 10-20 cm and 20-40 cm for E. dunnii, and from the layers 40 - 60 cm and 60 - 80 cm for clone E. saligna, which shows the different relations between the genetic material and the analyzed soil profiles. The depth of the A + B horizons, the silt, the organic matter and the concentration of boron, potassium and calcium were the attributes that gave the highest contribution in the models to explain the productive capacity of the profiles analyzed by dominant height. / O emprego de técnicas para determinação da capacidade produtiva de um sítio florestal depende de sua sensibilidade para avaliar ou prever a interação entre os fatores genéticos da espécie e o ambiente (clima, solo, fisiografia). O presente trabalho desenvolvido na região da Metade Sul do Estado do Rio Grande do Sul teve como objetivo avaliar a influência dos atributos do solo, em diferentes classes de solo, com a capacidade produtiva através da altura dominante (h100) o Eucalyptus saligna (clone 32864) e plantios seminais de Eucalyptus dunnii. Desta forma, selecionaram-se 16 parcelas de inventário florestal com base no material genético e variáveis dendrométricas como a altura dominante (h100), incremento médio anual (IMA) e volume de madeira com casca (m3/ha-1) projetados para os sete anos, sendo 9 parcelas de E. dunnii e 7 parcelas de E. Saligna. Em cada sítio selecionado abriu-se trincheiras para classificação do solo, coleta de amostras para análises químicas (pH, MO, Ca, Mg, Al, P, S, K, Zn, Cu, B, CTC ph7, V) físicas (granulometria, densidade de partícula e do solo, porosidade total, macro e microporosidade, curva de retenção de água no solo, condutividade hidráulica saturada) e coleta de serapilheira. Os perfis/parcelas apresentaram variações quanto as classes de solos, altura dominante, índice de sítio, material de origem, características morfológicas, químicas e físicas do solo e quantidade de serapilheira. Foram analisadas 4 classes de solos representativas da região do estudo: Argissolos (PVe, PVd, PBACd, PBACe, PAd), Neossolos (RRd), Luvissolos (TCo) e Cambissolo (CXbd). A altura dominante (h100) apresenta altura mínima de 22,9 m (Perfil 13 - RRd ) e máxima de 29,3 m (Perfil 10 -TCo) para E. dunnii e para o clone E. saligna o IS apresenta altura mínima de 22,4 m (Perfil 11 - PAd) e 28,7 m (Perfil 16 - PVe). A análise estatística entre altura dominante (h100) e os atributos físicos, químicos e morfológicos do solo foi realizada através do emprego da análise de regressão múltipla buscando-se verificar a significância das variáveis de entrada para determinação da altura dominate. As equações que melhor relacionaram a altura dominante (h100) com os atributos do solo foram as oriundas das camadas de 10 a 20 cm e da camada de 60 a 80 cm quando considerados os dois materiais genéticos. Entretanto, quando os materiais genéticos foram avaliados separadamente as equações que melhor relacionaram o índice de sítio com os atributos do solo foram as equações oriundas das camadas de 10 a 20 cm e 20 a 40 cm para E. dunnii, 40 a 60 cm e 60 a 80 cm para o clone de E. saligna, evidenciando relações distintas entre os materiais genéticos e o solo nos perfis analisados. A profundidade dos horizontes A+B, o silte, a matéria orgânica e os teores de boro, de potássio e cálcio foram os atributos que mais contribuíram nos modelos para explicar a capacidade produtiva nos perfis analisados através da altura dominante (h100).

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this study was to evaluate the performance and carcass characteristics of cattle breed Aberdeen Angus steers of small and medium frame score slaughtered the same degree of completion of housing (average 6.39 mm). To 18 steers were used with age and weight of 298 days and 202.17 kg at entry into the confinement. The animals were confined for 158 days and slaughtered at average live weight of 430 days and 428.94 kg. The feed was composed of sorghum silage and concentrate in the ratio of 60:40 in the dry matter in the first 63 days and after 50:50 until slaughter. The frame was calculated using the formula F=-11, 548+0,4878*h*0,0289*ID+0,0000146*ID²+0,0000759*h*ID. Steers with medium frame score showed superiority in important aspects of marketing, as the initial weight (y=107.87+250.04B; P=.0002), final (y=308.14+32.07B; P=.0001), the empty body (y=255.07+30.74B; P<.0001) and hot carcass (y=153.91+21.09B; P<.0001) and cold (y=150.29+20.78B; P<.0001). Measures of muscle content as the Longissimus dorsi area in relation to cold carcass weight (ȳ=32.64-1.53; P=.0477) and empty body (ȳ=16.3-0.55B; P=.0419) were lower in of the carcass. Carcass conformation (P=.4660) Longissimus dorsi area in cm² (P=.6999),cushion thickness (P=.3578) were similar between the small and medium frame score. The commercial cuts, forequarter (ȳ=54.93+7.84B; P<.001), rib (ȳ=21.33+3.31B; P=.009) and back (ȳ=74.02+9.64B; P=.0003) in kg was higher in medium frame score. As a percentage cut back fell .18% with the incrase in frame score (ȳ=49-.18B P.0404). Weight tissue constituents of the carcass increased with the frame score of the steers, as on the percentage muscle tissue decreased by .57% (ȳ=61.63-.57B; P=.0410). The meat of Longissimus dorsi muscle of steers Aberdeen Angus of small and medium frame score showed intramuscular fat with a mean average of 10.11 points (P=.7034), red color with an average of 4.33 points (P=.3724), fine texture with a tendency to thin with an average 4.61 points (P=.3075) and the shear force with an average of 2.72 kg/cm² (P=.4004). Composition chemical of beef Longissimus dorsi muscle frame score steers Aberdeen Angus presented moisture with 72.27% (P=4355), crude protein of 19.34% (P=4150), lipid with 3.96% (P=9071), minerals with 4.43% (P=9842) and cholesterol to 50.25 mg/100g of meat (P=.2375). The small and medium frame score did not influence trhe fatty acids palmitic (P=.0790), stearic (P=.2455), oleic (P=.3046), linoleic (P=.9456), occurring change in the composition fatty acids myristic (y=1,85+0,12F; P=.043). The introduction of the frame score in studies of meat composition may be important in determining the frame score of steers with the nutritional features of the best meat. The medium frame score of Aberdeen Angus steers had higher head weight (y=9.35+.49B; P=.0212), feet (=5.38+.57B; P=.0059), tongue (y=.93+.05B; P=.0154), heart (y=1.45+.07B; P=.0183), inguinal adipose tissue (y=1.79+.21B; P=.0336) and adipose tissue is not part of the carcass plus to this in the meat (y=88.5+3.70B; P=.0086). Steers with small frame score were more (y=1.46-.08B; P=.0407) in the participation of the lungs in relation to empty body weight Aberdeeen Angus Steers. The small and medium frame score did not affect the participation of the rumen-reticulum, abomasums, omasum, intestines and contents of the gastrointestinal tract weight in relation to body weight an empty body weight. / O trabalho teve por objetivo avaliar o desempenho, as características da carcaça, da carne e os componentes não integrantes da carcaça de bovinos da raça Aberdeen Angus superjovens de biótipo pequeno e médio abatidos o mesmo grau de acabamento da carcaça (média de 6,39 mm). Foram utilizados 18 novilhos com idade e peso no ingresso no confinamento de 298 dias e 202,17kg. Os animais foram confinados durante 158 dias, abatidos com idade e peso vivo médio de 430 dias e 428,94kg. A alimentação foi composta por silagem de sorgo e concentrado, na relação volumoso:concentrado de 60:40 na matéria seca, nos primeiros 63 dias e após 50:50 até o abate. O biótipo foi calculado utilizando a fórmula B=-11,548+0,4878*h*0,0289*ID+0,0000146*ID²+0,0000759*h*ID. Os novilhos com biótipo médio apresentaram superioridade nos aspectos importantes de comercialização, como o peso inicial (y=107,87+250,04B; P=0,0002), final (y=308,14+32,07B; P=0,0001), de corpo vazio (y=255,07+30,74B; P<0,0001), de carcaça quente (y=153,91+21,09B; P<0,0001) e fria (y=150,29+20,78B; P<0,0001). As medidas de musculosidade da carcaça como a área de Longissimus dorsi em relação ao peso de carcaça fria (ȳ=32,64-1,53; P=0,0477) e de corpo vazio (ȳ=16,3-0,55B; 0,0419) foram menores nos novilhos de biótipo médio. A conformação da carcaça (P=0,4660), área de Longissimus dorsi em cm² (P=0,6999), espessura de coxão (P=0,3578) foram semelhantes entre os biótipos pequeno e médio. Os cortes comerciais, dianteiro (ȳ=54,93+7,84B; P<0,0001), costilhar (ȳ=21,33+3,31B; P=0,009) e traseiro (ȳ=74,02+9,64B; P=0,0003) em kg foi superior para o biótipo médio. Em percentagem o corte traseiro foi maior no biótipo pequeno (ȳ=49,00-0,18B; P=0,0404). Em peso os tecidos constituintes da carcaça aumentaram com o biótipo do novilho, à percentagem o tecido muscular apresentou queda de 0,57% (ȳ=61,63-0,57B; P=0,0410). A carne do músculo Longissimus dorsi de bovinos superjovens da raça Aberdeen Angus de biótipo pequeno e médio apresentou gordura intramuscular média com média de 10,11 pontos (P=0,7034), coloração vermelha com média de 4,33 pontos (P=0,3724), textura fina com tendência a muito fina com valor médio de 4,61 pontos (P=0,3075) e macia pelo força ao cisalhamento com média de 2,72 kgf/cm² (P=0,4009). O biótipo pequeno e médio apresentaram na carne do músculo Longissimus dorsi proporções de umidade com 72,27% (P=0,4355), de proteína bruta com 19,34% (P=0,4150), de lipídios com 3,96% (P=0,9071), de minerais com 4,43% (P=0,9842) e de colesterol com 50,25 mg/100g de carne (P=0,2375). O biótipo pequeno e médio não influenciaram nos ácidos graxos palmítico (P=0,0790), esteárico (P=0,2455), oléico (P=0,3046), linoléico (P=0,9456), ocorrendo alteração na composição do acido graxo mirístico (y=1,85+0,12B; P=0,043). A introdução do biótipo em estudos da composição da carne pode ser importante na determinação do biótipo de novilhos com melhores características nutraceuticas da carne. O biótipo médio dos novilhos Aberdeen Angus superjovens apresentaram maior peso de cabeça (y=9,35+0,49B; P=0,0212), das patas (y=5,38+0,57B; P=0,0059), da língua (y=0,93+0,05B; P=0,0154), do coração (y=1,45+0,07B; P=0,0183), do tecido adiposo inguinal (y=1,79+0,21B; P=0,0336) e do tecido adiposo não integrante da carcaça somado ao presente na carne (y=88,85+3,70B; P=0,0086). Os novilhos com biótipo pequeno apresentaram superioridade (y=1,46-0,08B; P=0,0407) na participação dos pulmões em relação ao peso de corpo vazio.Os novilhos Aberdeen Angus de biótipo pequeno e médio não alteraram a participação do rúmen-retículo, abomaso, omaso, intestinos e conteúdo do trato gastrointestinal em peso, em relação ao peso vivo e ao peso de corpo vazio.

La mission SWOT (Surface Water and Ocean Topography), menée par le CNES et le JPL et dont le lancement est prévu pour 2020, marque un tournant majeur pour l'altimétrie spatiale, à la fois en océanographie et en hydrologie continentale. Il s'agit de la première mission interférométrique SAR dont l'objectif spécifique est la mesure de la hauteur des eaux. L'instrument principal de la mission, KaRIn, un radar interférométrique en bande Ka, présente des caractéristiques particulières : angle de visée proche du nadir (0.6 à 3.9°), faible longueur d'onde (8.6 mm) et courte base stéréoscopique (10 m). Ces spécificités techniques entrainent des particularités propres à SWOT, à la fois en termes de phénoménologie et de traitement des données. Par ailleurs, du fait de la nature et du grand volume des données, de nouvelles méthodes de traitement sont envisagées, qui se distinguent de celles des missions interférométriques antérieures. Pour le mode " Low Rate " (LR) dédié à l'océanographie, une grande partie du traitement se déroulera à bord pour limiter le volume de données à transmettre au sol. Le mode " High Rate" (HR) visant principalement l'hydrologie continentale, présente lui aussi des originalités en termes de traitement, essentiellement réalisé au sol, de par la grande diversité de structure des surfaces d'eau qui seront observées. Pour les deux modes, la stratégie d'inversion de la phase en hauteurs géolocalisées ne peut être calquée sur celles des missions antérieures, fondées sur le déroulement spatial de la phase interférométrique. L'approche retenue est d'utiliser, autant que possible, un modèle numérique de terrain (MNT) de référence pour lever l'ambiguïté de phase et procéder directement à l'inversion de hauteur. Ceci permet à la fois de gagner en temps de traitement et de s'affranchir de l'utilisation des points de contrôle, difficiles à obtenir sur les océans comme sur les continents, du fait des variations de niveau d'eau et un rapport signal à bruit très faible sur les zones terrestres. Dans les cas où la précision du MNT de référence n'est pas suffisante pour assurer correctement le déroulement de la phase, des méthodes visant à détecter et réduire les erreurs sont proposées. Afin de faciliter l'utilisation des hauteurs géolocalisées issues de la phase l'interférométrique en mode HR, nous proposons une méthode qui permet d'améliorer considérablement la géolocalisation des produits, sans dégrader l'information de hauteur d'eau. / The SWOT mission (Surface Water and Ocean Topography), conducted by CNES and JPL, and scheduled for launch in 2020, is a major step forward for spaceborne altimetry, both for oceanography and continental hydrology. It is the first interferometric SAR mission whose specific objective is the measurement of water surface height. The main instrument of the mission, KaRIn, a Ka-band Radar Interferometer, has particular characteristics: very low incidence angle (from 0.6 to 3.9°), short wavelength (8.6 mm), and short baseline (10 m). This technical configuration leads to properties that are specific to SWOT, both in terms of phenomenology and data processing. Moreover, due to the nature and the huge volume of data, new processing methods, different from those used in previous interferometric mission, are considered. For the Low Rate (LR) mode dedicated to oceanography, a large part of the processing will take place onboard to limit the data volume transmitted to ground. The High Rate (HR) mode, mainly targeting continental hydrology, also present original characteristics in terms of processing, essentially conducted on ground, due to the large diversity in the structure of the observed water surfaces. In both modes, the strategy for conversion of phase into geolocated heights cannot be directly based on those of previous missions, relying on spatial phase unwrapping. The approach retained here is to use, as far as possible, a reference Digital Terrain Model (DTM) to remove the phase ambiguity and proceed directly to height inversion. This allows both to reduce the computing time and to avoid the need for ground control points, which are difficult to obtain both over oceans and continental surfaces, due to varying water level and very low signal-to-noise ratio over land. For cases where the precision of reference DTM is not good enough to ensure a correct phase unwrapping, methods to detect and reduce the errors are proposed. To facilitate the use of the geolocated heights derived from the interferometric phase in HR mode, we propose a method that permits to significantly improve the geolocation of the products, without degrading the water height information.

Soll die Massenbilanz des antarktischen Eises bestimmt werden, so ist das grundlegend mit der Beobachtung dessen Geometrie, Kinematik und Dynamik verbunden. Basis dieser Arbeit sind Beobachtungen von Eisoberflächenhöhen und Fließgeschwindigkeiten im Einzugsbereich des Helen-Gletschers südlich der russischen Antarktisstation Mirnyj und im Einzugsbereich des Hays-Gletschers südöstlich der Station Molodëžnaja. 1962 wurde von Mirnyj ausgehend das sich über 100km in südliche Richtung erstreckende geodätisch-glaziologische Triangulationsnetz Mirnyj angelegt. 1972 erfolgte die Realisierung einer Traverse über das Einzugsgebiet des Hays-Gletschers. Beide Regionen wurden in den folgenden Jahren mehrfach wiederholt beobachtet. Eine erneute Wiederholungsmessung von Eisoberflächenhöhen und Fließgeschwindigkeiten konnte zwischen 2005 und 2009 realisiert werden. Diese Arbeit beleuchtet diese Aktivitäten und beschreibt die Ableitung langzeitiger Eismassenveränderungen über Zeiträume mehrerer Dekaden. Die historische Datengrundlage, die Realisierung eines einheitlichen Bezugssystems sowie die verwendeten Beobachtungsverfahren werden ausführlich erläutert. Der Vergleich von Eisoberflächenhöhen der 2000er Jahre und Höhen der 1960er bzw. 1970er Jahre führt zur Abschätzung langzeitiger Veränderungen der Eisoberflächenhöhe für beide Regionen.

Groat oil content and composition are important quality traits in oats (Avena sativa L). These traits are controlled by many genes with additive effects. The chromosomal regions containing these genes, known as quantitative trait loci (QTL), can be discovered through their close association with markers. This study investigated total oil content and fatty acid components in an oat breeding population derived from a cross between high oil ('Dal') and low oil ('Exeter') parents. A genetic map consisting of 475 DArT (Diversity Array Technology) markers spanning 1271.8 cM across 40 linkage groups was constructed. QTL analysis for groat oil content and composition was conducted using grain samples grown at Aberdeen, ID in 1997. QTL analysis for multiple agronomic traits was also conducted using data collected from hill plots and field plots in Ottawa, ON in 2010. QTLs for oil content, palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2) and linolenic acid (18:3) were identified. Two of the QTLs associated with oil content were also associated with all of the fatty acids examined in this study, and most oil-related QTL showed similar patterns of effect on the fatty acid profile. These results suggest the presence of pleiotropic effects on oil-related traits through influences at specific nodes of the oil synthesis pathway. In addition, 12 QTL-associated markers (likely representing nine unique regions) were associated with plant height, heading date, lodging, and protein content. The results of this study will provide information for molecular breeding as well as insight into the genetic mechanisms controlling oil biosynthesis in oat.

I kursen Examensarbete i Integrerad produktutveckling på Högskolan i Skövde har under våren 2017 ett produktutvecklingsprojekt för Kinnarps utförts av designingenjörsstudenterna Eva Henriksson och Sofie Johansson. Kinnarps är ett företag som tillverkar möbler för offentliga miljöer och vill nu i samband med deras nya satsning, att utveckla utformningen av hur lärmiljöer ser ut, ta fram ett höj- och sänkbart elevbord anpassat för årskurs 4-9. Under projektet användes och utvärderades också QFD – Quality Function Deployment som ett verktyg för att identifiera och uppfylla rätt kundbehov. Förstudien och användandet av QFD innebar bland annat att genomföra intervjuer och observationer av användare och målgruppen, identifiera trender i lärmiljöer, utföra konkurrentanalyser, utvärdera och vikta kundbehov samt att översätta behoven till kvalitéer som gick att uppfylla.Förstudien visade på att bordets viktigaste kvaliteter att uppfylla var att det skulle vara flexibelt, mobilt, tyst och enkelt att justera.Konceptutvecklingen inleddes med att identifiera och utvärdera olika höj- och sänkmekanismer. Därefter påbörjades konceptgenerering som utfördes med hjälp av olika kreativitetsmetoder. Koncepten utvärderades och sållades kontinuerligt under processen efter hur väl de uppfyllde kundbehoven samt genom användartester och återkoppling med målgruppen. Inför konceptvalet återstod till sist två koncept. Beslutet av det slutliga konceptet grundades i hur väl det uppfyllde de identifierade kundbehoven.Resultatet blev ett bord som uppfyller de ställda kraven och passar väl in i de lärmiljöer som finns idag men är också anpassat för hur lärmiljöer troligtvis kommer se ut i framtiden. Bordet har den funktionalitet som efterfrågades av användarna samtidigt som det har en utformning som är unik och tilltalande. / During the spring semester of 2017 a product development project has been carried out by two Design Engineering Students, Eva Henriksson and Sofie Johansson, in cooperation with Kinnarps. Kinnarps is a company who develops and sells furniture for public environments and as they are now focusing on the development of how educational spaces are formed and furnished they wanted to develop a height adjustable student desk for pupils between the ages of 10 to 16. To be able to reassure whether the correct customer requirements were identified and fulfilled in the right way QFD – Quality Function Deployment was used and analyzed as a part of the project. The use of QFD during the pre-study included, amongst other things, the execution of interviews and observations of users and the target group, performing competitive analyses, looking into trends , evaluate and weighing the importance of different needs and translating those into measureable specifications.The pre-study showed that needs like mobility, flexibility, simple adjustment and that the table should be as quiet as possible were the most important ones.The concept generation phase started by identifying and evaluating different options of height adjustment mechanisms. Creativity methods were used to generate ideas on how different parts of the table could be constructed. The generated concepts were then evaluated and screened continuously by looking on how well they fulfilled the customer requirements and through user tests and feedback from the target group. Two concepts remained before the final selection. The choice between these two concepts were based on to which extend each of them fulfilled the customer requirements. The final design of the table fulfills the requirements that were set and fits well into the educational spaces as they are formed today and how they probably will be designed in the future. The functionality that were requested by the users have been fulfilled while the table still has a unique and appealing look.

The determination of adiposity in adolescents is often assessed with calculations of body mass indices (BMI). Researchers often obtain these measurements from self-reported (SR) values. The purpose of this study was to determine the accuracy of SR height, weight, and calculated BMI (from height and weight). SR and actual measured (ME) BMI values were compared with standards from the FITNESSGRAM® Healthy Fitness Zone (HFZ) classifications. SR height and calculated BMI were found to be accurate while SR weight was, on average, underreported by 4.77 lbs. Because of these errors in SR height and weight, accuracy of classification into the FITNESSGRAM® HFZ was compromised. Consequently, it is important that researchers ascertain actual values of height and weight when measuring adolescents rather than use those from self-reports.

La hauteur des arbres est un trait écologique majeur représentant l'intensité de la compétition pour la lumière. De plus, la croissance des arbres est le résultat de multiples compromis afin de maintenir leur orientation verticale et leur stabilité mécanique tout en assurant les autres fonctions écophysiologiques. Le contrôle de l'orientation de la croissance est réalisé par deux mécanismes: la croissance différentielle au niveau du méristème apical et la formation de bois de réaction au cours de la croissance secondaire. Cependant, la modélisation simultanée de la croissance et des rétroactions biomécaniques dépasse le cadre classique de la mécanique des structures. En effet, le concept de configuration de référence devient imprécis dû à l'apparition de nouveaux points matériels libres de contraintes sur une surface déformée au cours de la croissance. Dans cette thèse, un nouveau formalisme mathématique est proposé à partir de la théorie des poutres et modélise simultanément les effets de la croissance et de la biomécanique de l'arbre. Afin de résoudre le système d'équations aux dérivées partielles, de nouvelles méthodes numériques sont développées et tiennent compte de la dépendance entre l'espace et le temps. Enfin, deux problèmes de contrôle optimal sont analysés, modélisant les stratégies d'allocation dynamique de la biomasse pour la croissance primaire et secondaire, en fonction de différents contextes écologiques. Ce travail offre de nouvelles perspectives sur les mathématiques de la mécanique de la croissance et ses applications en biologie. / Height is a major ecological trait for growing trees, representing the intensity for light competition. Moreover, tree height results from a trade-off between different functions, including tree mechanical stability. Trees develop growth strategies to maintain their vertical orientation and mechanical stability, in addition to other ecophysiological functions, through differential primary growth near the shoot apical meristem and formation of reaction wood during secondary growth. However, this coupling is a problematic issue since the progressive addition of new material on an existing deformed body makes the definition of a reference configuration unclear. This thesis presents a new mathematical framework for rod theory modelling simultaneously the interactions between the growth process and tree biomechanics. In order to solve the obtained system of partial differential equations, new numerical methods are developed and take into account the dependence between space and time, which is a specific feature of surface growth problems. Finally, the present work addresses the mathematical formulation of two optimal control problems characterising tree's growth strategies. Growth strategies are analysed with respect to the ecological context, through two variables, which are the ratio of biomass allocated to primary growth and the distribution of biomass allocated to secondary growth along the growing stem. This work gives new insights to the mathematical framework of surface growth mechanics and its applications in biology.

O presente experimento foi conduzido no Departamento de Produção Animal da ESALQ/USP, em Piracicaba (SP), entre 15/12/98 e 04/07/99. Os tratamentos foram constituídos pelas combinações entre três cultivares de Cynodon spp. (Tifton-85, Florakirk e Coastcross) e quatro alturas de pasto (5, 10, 15 e 20 cm) mantidas por pastejo de ovinos em regime de lotação contínua e taxa de lotação variável. O delineamento experimental utilizado foi o de blocos completos casualizados em arranjo de parcelas subdivididas com quatro repetições. As parcelas corresponderam aos cultivares e as subparcelas (unidades experimentais) às alturas de pasto. Foram analisadas as seguintes variáveis: biomassa na área total, densidade populacional de perfilhos, massa por perfilho, massa de folha por perfilho e área foliar por perfilho. A partir dessas medições foram realizados cálculos de índice de área foliar do pasto (IAF), volume por perfilho, relação folha:haste por perfilho e relação área foliar:volume por perfilho (R). O mecanismo de compensação tamanho/densidade populacional de perfilhos operou em pastagens de Cynodon spp.. No entanto, as inclinações das retas foram consistentemente maiores que a proposição teórica de 3/2. Perfilhos individuais de Cynodon spp. apresentaram um padrão de crescimento isométrico e parecem agruparse em clones para assegurar estratégia competitiva e otimização de IAF. Pastos mantidos a 5 cm durante o outono apresentaram densidades populacionais reduzidas, indicando um padrão de tolerância ao pastejo dependente da época do ano. Tifton-85 e Coastcross apresentaram uma capacidade de aumento em biomassa que pode ir além da altura de 20 cm, enquanto que para o cultivar Florakirk essa capacidade situou-se em torno de 20 cm. O estádio reprodutivo das plantas interferiu de forma significativa nos processos de competição intra-específica e dinâmica populacional de perfilhos. / The experiment was conducted at the Department of Animal Production, ESALQ/USP, Piracicaba (SP), from 15/12/98 until 04/07/99. Treatments were combinations of three Cynodon spp. cultivars (Tifton-85, Florakirk and Coastcross) and four sward surface heights (SSH) (5, 10, 15 and 20 cm) maintained by sheep under continuous stocking and variable stocking rate. A complete randomised block design was used, with treatments arranged in split-plot and replicated four times. Grass cultivars were assigned to plots and SSH to sub-plots. Pastures responses evaluated were: total biomass above ground level, tiller population density, tiller weight, leaf mass and leaf area per tiller. From these measurements calculations of sward leaf area index (LAI), tiller volume, tiller leaf:stem ratio and tiller leaf area:volume ratio (R) were derived. A tiller size/population density mechanism operated in Cynodon spp. However, a slope steeper than the theoretical expectation of 3/2 was observed. Individual tillers presented an isometric pattern of growth and seemed to demonstrate a clonal integration among tillers in order to enhance competitive ability and optimise LAI. Swards maintained at 5 cm during autumn presented reduced tiller population densities, indicating a pattern of grazing tolerance dependent of time of the year. Tifton-85 and Coastcross pastures showed a capacity to increase total biomass that could go beyond 20 cm, while Florakirk stabilised around that SSH. Reproductive development of plants interfered with the processes related to intra-specific competition and tiller population dynamics.

As pastagens ocupam uma grande extensão territorial no Brasil constituindo a principal fonte de alimento para os ruminantes. Entretanto, seu manejo, ainda é frequentemente realizado de forma extensiva e extrativista, tornando a atividade pouco competitiva. O estudo de estratégias de manejo do pastejo sob lotação contínua contribui para a diversificação e intensificação dos sistemas de produção de ruminantes baseados em pastagens. O objetivo foi descrever e explicar diferenças no potencial produtivo e nas características qualitativas, através de atributos estruturais e químico-bromatológicos da Brachiaria híbrida (Brachiaria ssp.) Convert HD 364 em resposta ao manejo do pastejo sob lotação contínua mimetizada e taxa de lotação variável. O experimento foi conduzido em Piracicaba, no verão de 2013. Foram testadas três intensidades de desfolhação determinadas por alturas de manejo de dossel (10, 25 e 40 cm) em combinação com dois ritmos de crescimento (50 e 250 kg N ha-1 ano-1) num arranjo fatorial (3 x 2) e delineamento em blocos completos casualizados. Variáveis-resposta medidas incluíram massa, acúmulo e taxa de acúmulo de forragem, IAF, composição morfológica e valor nutritivo (Proteína bruta - PB, Fibra insolúvel em detergente neutro- FDN, Digestibilidade in vitro da matéria orgânica - DIVMO) da forragem. Os maiores valores de acúmulo e taxa de acúmulo foram registrados para os dosséis mantidos a 40 cm de altura (12650 kg MS ha-1ano-1 e 110 kg MS ha-1 dia-1, respectivamente) e para dosséis adubados com 250 kg N ha-1(13974 kg MS ha-1ano-1 e 126 kg MS ha-1dia-1, respectivamente). Esse mesmo tratamento apresentou os maiores valores de IAFs (8,1). A massa de forragem não sofreu influência do N, mas respondeu ao aumento da altura e foi maior para os pastos mantidos a 40 cm (14650 kg MS ha-1). Mais N (250 kg ha-1) resultou em maior proporção de folhas (26 %). Maior proporção de colmo (40%) ocorreu no dosséis de 40 cm e adubados com 50 kg N ha-1 e proporções de material morto foram maiores (49%) nos tratamentos de 10 cm de altura e 50 kg de N ha-1. Dosséis de 10 cm adubados com 50 kg N ha-1, embora com menor produtividade, resultaram em maior DIVMO (670 g kg-1) e PB (153 g kg-1 e 165 g kg-1, para 10 cm e 250 kg N ha-1, respectivamente). O teor de FDN foi maior para 40 cm (545g kg-1) e com 50 kg N ha-1(550 g kg-1). A adubação nitrogenada promove ganhos em produtividade e resulta em forragem com melhor valor nutritivo, enquanto que incrementos em altura do dossel promovem maior acúmulo total e taxa média de acúmulo de forragem, até o ponto em que ocorre estabilidade da produção (25 cm), sendo assim o tratamento que apresentou melhor eficiência produtiva aliada a um bom valor nutritivo foi o com 25 cm de altura do dossel e 250 kg ha-1 de N. / Pastures occupy a large area in Brazil and are key to the country\'s livestock industry, which is almost exclusively forage-based. Grazing management, however, is largely empirical in the country, and technical guidelines for managing specific grasses are either scarce or poorly adopted, which hinders the competitiveness of the activity. Establishing sound management guidelines for key grasses can improve animal output and profitability of the livestock enterprise. The objective was to describe and explain differences in the productive potential and the qualitative traits of Convert HD 364 brachiariagrass through the characterization of agronomic and sward structural attributes as well as forage nutritive in response to three grazing intensities and under two growth rates under continuous stocking and variable stocking rate in a mob-grazing experimental protocol. The study was conducted in Piracicaba, in summer of 2013. Experimental paddocks received treatments corresponding to all possible combinations among three sward heights (10, 25, and 45 cm) and two growth rates generated by two N rates (50 and 250 kg N ha-1) split-applied monthly during the experimental period. The experimental design was a randomized complete block with a factorial arrangement. Response variables included forage accumulation and accumulation rate, LAI, plant-part composition of forage on offer, as well as plant-part composition and nutritive value (crude protein - CP, neutral detergent insoluble fiber - NDF digestibility in vitro organic matter - IVDMD) of forage. The highest values of forage accumulation and accumulation rate were recorded for swards kept at 40 cm (12650 kg DM ha-1 yr-1 and 110 kg ha-1 d-1, respectively) and for swards fertilized with 250 kg N ha-1 (13974 kg DM ha-1 yr-1 and 126 kg DM ha-1 day-1, respectively). This same combination resulted the highest LAI (8.1). Forage mass was affected by sward height but not by N rates being higher for 40-cm (14650 kg DM ha-1). Treatments with higher N (250 kg ha-1) resulted in forage with a higher proportion of leaf (26%). Higher percentages of stem (40%) were measured in swards grazed at 40 cm and fertilized with 50 kg N ha-1 while the proportion of dead material was higher (49%) in 10-cm swards receiving 50 kg N ha-1 of N. Swards kept at 10 cm and receiving 50 kg N ha-1, although less productive, resulted in forage with higher IVOMD (670 g kg-1). Forage in 10-cm swards had 153 g kg-1 crude protein and that from swards receiving 250 kg N ha-1 had 165 g kg-1. Neutral detergent fiber concentration was higher in forage from 40-cm swards (545 g kg-1) and from those receiving 50 kg N ha-1 (550 g kg-1), which is also associated with the maturity of the tissues at the time of harvest. Nitrogen fertilization promotes gains in productivity and results in forage with better nutritive value, whereas increases in canopy height promote higher total accumulation and rate of herbage accumulation, up to 25 cm. The treatment that combines high productivity with high nutritive value is 25 cm canopy height and 250 kg ha-1.