La fertilisation phosphatée est très répandue dans les pratiques agricoles Nord-Américaines. Bien que généralement très efficace pour augmenter la production végétale, son utilisation peut engendrer certaines contaminations environnementales. Afin de diminuer ce problème, plusieurs pratiques de gestion sont envisagées. Parmi celles-ci, on retrouve l’intéressante possibilité de manipuler la flore microbienne car cette dernière est reconnue pour son implication dans bons nombres de processus fondamentaux liés à la fertilité du sol. Cette étude a démontré que lors d’essais en champs, la forme de fertilisant ajouté au sol ainsi que la dose de phosphore (P) appliquée avaient un impact sur la distribution des microorganismes dans les différentes parcelles. Une première expérience menée sur une culture de luzerne en prairie semi-aride a montré que les échantillons provenant de parcelles ayant reçu différentes doses de P présentaient des différences significatives dans leurs communautés bactériennes et fongiques. La communauté de CMA est restée similaire entre les différents traitements. Une deuxième expérience fut menée pendant trois saisons consécutives afin de déterminer l’effet de différentes formes de fertilisation organiques et minérale ajustées selon une dose unique de P sur les populations bactériennes et fongiques d’une culture intensive de maïs en rotation avec du soja. Les résultats des analyses ont montrés que les populations varient selon le type de fertilisation reçu et que les changements sont indépendants du type de végétaux cultivé. Par contre, les populations microbiennes subissent une variation plus marquée au cours de la saison de culture. La technique de DGGE a permis d’observer les changements frappant la diversité microbienne du sol mais n’a permis d’identifier qu’une faible proportion des organismes en cause. Parallèlement à cette deuxième étude, une seconde expérience au même site fut menée sur la communauté de champignons mycorhiziens à arbuscules (CMA) puisqu’il s’agit d’organismes vivant en symbiose mutualiste avec la majorité des plantes et favorisant la nutrition de même que l’augmentation de la résistance aux stress de l’hôte. Ceci permit d’identifier et de comparer les différents CMA présents dans des échantillons de sol et de racines de maïs et soja. Contrairement aux bactéries et aux champignons en général, les CMA présentaient une diversité très stable lors des différents traitements. Par contre, au cours des trois années expérimentales, il a été noté que certains ribotypes étaient significativement plus liés au sol ou aux racines. Finalement, l’ensemble de l’étude a démontré que la fertilisation phosphatée affecte la structure des communautés microbiennes du sol dans les systèmes évalués. Cependant, lors de chaque expérience, la date d’échantillonnage jouait également un rôle prépondérant sur la distribution des organismes. Plusieurs paramètres du sol furent aussi mesurés et ils présentaient aussi une variation au cours de la saison. L’ensemble des interactions possibles entre ces différents paramètres qui, dans certains cas, variaient selon le traitement appliqué, aurait alors probablement plus d’impact sur la biodiversité microbienne que la seule fertilisation. / Phosphorus fertilization is a widespread practice in North American agriculture. Although it is generally efficient to increase yields, its use can also induce some environmental contaminations. Several management practices are considered in order to decrease this problem. Among these possibilities there is the challenging one of manipulating microbial flora, which is well known for its implication in many processes related to soil fertility. We have demonstrated in field trials that both the form of fertilizer added to soil and the applied P amounts impact microbial distribution in plots. A first experiment performed on alfalfa monocultures in semi-arid prairie conditions demonstrated that samples coming from plots that had received different doses of P fertilizer presented significant differences on their bacterial and fungal communities. AMF population remained stable between treatments. A second experiment was conducted over three growing season of an intensive maize/soybean rotation cropping system. It aimed to determine the effect of different organic and mineral fertilizers containing equal P amount on bacterial and fungal populations. It was demonstrated that these communities varied according to the fertilizer type applied. Changes are independent from the grown crop. However, microbial populations have undergone greater variation within each growing season. DGGE approach allowed to observe changes occurring in soil microbial diversity but have only permit to identify a small proportion of organisms. A second experiment in the latter study was performed on the same site and focused on arbuscular mycorrhizal fungi (AMF) as they are organisms living in a mutualistic symbiosis with most land plants and increasing host nutrition and resistance to stresses. It led to the identification and comparison of the different AMF found in maize and soybean soil and root samples. In opposition to what was observed with bacteria and fungi previously, AMF presented a very stable diversity between the different treatments. However, some ribotypes were significantly more present in soil or roots during each growing season. Finally, our whole project demonstrated that P fertilization affected microbial community structure on studied sites. Nevertheless, in each experiment, sampling time also played a substantial role in the organism distribution. Many soil parameters were also monitored and presented a seasonal variation. The sum of possible interactions between these parameters, which in some cases varied according to treatment, would thus have more impact on microbial diversity that the sole fertilization.

Content removed due to copyright restriction: Appendix IV. Managing fruit soluble solids with late-season deficit irrigation in drip-irrigated processing tomato production (HortScience 40: 1 857-1861 ). / Improved fertilizer and irrigation management has become increasingly important for tomatoes (Lycopersicon esculentum Mill.) grown for processing. To reduce potential nutrient loss to the environment due to excessive supply, fertilizer recommendations should reflect plant demand determined in an optimal root environment. An aeroponics experiment examined the effect of low and high nutrient supply during vegetative growth, fruit development and fruit ripening. The use of aeroponics in a glasshouse environment allowed control of fertility directly at the root surface. A further experiment applying aeroponics results was established in the field using drip-fertigation. Both studies were conducted at Massey University, Palmerston North. Across experiments, fruit yield was largely determined by vegetative growth in the 6-8 weeks after transplanting; high fruit yields (> 90 Mg ha-1) were associated with improved vegetative growth, and in particular larger leaf area. Mild N deficiency was the principal cause of poor vegetative growth in low nutrient supply treatments. Higher yield resulted from greater fruit number. Reinstating adequate fertility after vegetative growth stopped and fruit number was determined did not increase fruit yield. For maximum fruit yield, plant uptake of N and K was 9.4 and 13.8 g plant-1, respectively (equivalent to approximately 210 and 310 kg ha-1 at a medium planting density). Greatest nutrient uptake occurred during fruit development. Where practical, fertilizer application should be concentrated during fruit growth. Heavy late-season K fertigation did not increase the soluble solids concentration (SSC) of fruit. Although offering considerable flexibility in nutrient fertigation, the use of drip irrigation often results in undesirably low SSC. Late-season irrigation management strategies to increase fruit SSC without excessive yield loss were subsequently investigated in drip-irrigated fields. Two experiments were conducted at the University of California, Davis. Irrigation cutoff prior to fruit ripening reduced fruit set, decreased fruit size, and increased the incidence of fruit rots, making this approach uneconomical. Irrigation cutback to 25-50% of reference evapotranspiration imposed at the onset of fruit ripening (approximately 6 weeks preharvest) was sufficient to improve fruit SSC and maintain Brix yields (Mg Brix solids ha-1) compared to the current grower practice (late cutoff). Irrigation cutbacks imposed during ripening did not cause excessive canopy dieback, nor were fruit culls or rots increased when the crop was harvested at commercial maturity. Fruit colour and pH were not adversely affected by irrigation cutback. Brix monitoring of the earliest ripening fruit (when 30-60 % of the fruit surface shows a colour other than green) can help classify fields as to the severity of irrigation cutback required to reach desirable fruit SSC at harvest. Combined, these techniques offer considerable flexibility in managing fields for improved fruit SSC levels.

This study focuses on modelling community productivity, species abundance and richness, and the impact of climate change and alternative phosphorous fertiliser application strategies on pasture productivity by integration of decision tree and regression modelling approaches with a geographical information system (GIS) in a naturalised hill-pasture ecosystem in the North Island, New Zealand, using data derived from research conducted on hill-pastures over the last several decades. The results indicated that the decision tree models had a high predictive capability and clearly revealed the relative importance of environmental and management factors in influencing community productivity, species abundance and richness. Spring rainfall was the most significant factor influencing annual pasture productivity in the North Island, while hill slope was the most significant factor influencing spring and winter pasture productivity. Annual P fertiliser input and autumn rainfall were the most significant factors influencing summer and autumn pasture productivity, respectively. For species functional group abundance, soil Olsen P was the most significant factor influencing the relative abundance of low fertility tolerance grasses (LFTG) and moss, while soil bulk density, slope and annual P fertiliser input were the most significant factors influencing the relative abundance of legume, high fertility response grasses (HFRG) and flatweeds, respectively. Legume abundance was the most significant factor influencing species richness in the hill-pasture. Species richness increased with an increase in legume abundance and showed a tendency for a hump-shaped response. Grazing animal species also had a significant effect on species richness; pasture grazed by sheep had more species than pasture grazed by cattle. Climate change scenarios of temperature increases of 1-2 °C and rainfall changes of -20% to +20% would have a great impact (-46.2% to +51.9%) on pasture production in the North Island. Pasture in areas with relatively low rainfall had a higher response to increased P fertiliser input than pastures in areas with a relatively high rainfall. In conclusion, the integration of a GIS with decision tree and regression models in this study provided an approach for effective predictive modelling of community productivity, species abundance and richness in the hill-pasture. This modelling approach can also be used as a tool in pasture management such as in assessing the impact of climate change and alternative fertiliser management on pasture production.

The long-term small plot trial was established at the site in Jevíčko in 2003. Monitoring was realised in years 2006 and 2007. There were used four levels of utilisation (four, three, two and two cuts) and four fertilizer application (zero fertiliser, PK, N90PK, N180PK). The average dry matter production of grassland was 6.99 t ha-1, and it was significantly (P 0.01) reduced when subjected to four and three cut systems compared with a two-cut system. The number of botanical species fluctuated between 17.8 and 27.6. The intensive cutting system significantly (P 0.01) increased CP concentration (from 116.6 to 149.8 g kg-1 DM), CP production (from 787.4 to 951.1 kg ha-1), NEL concentration (from 5.09 to 5.57 MJ kg-1 DM), NEV concentration (from 4.81 to 5.41 MJ kg-1 DM), PDIE concentration (from 75.1 to 83.3 MJ kg-1 DM), and PDIN concentration (from 68.9 to 89.2 MJ kg-1 DM) when compared with the extensive cutting system. The intensive system significantly (P 0.01) decreased the fibre concentration from 292.2 to 234.2 g kg-1 DM. Increasing N fertiliser significantly (P 0.01) increased DM production (from 4.77 to 9.92 t ha-1), CP concentration (from 123.4 to 140.9 g kg-1 DM), CP production (from 545.7 to 1285.4 kg ha-1) and the PDIN concentration (from 68.5 to 83.8 g kg-1 DM) when compared to the control treatment (zero fertiliser).

La présente étude examine la variation de l’accumulation de la silice chez les graminées tropicales dans une perspective écologique et évolutive. La revue des travaux examinant l’étendue de la variation de la teneur en silice dans les graminées identifie trois groupes de facteurs influençant la silicification des graminées, notamment les facteurs génétiques (différence dans la capacité d’absorption racinaire, d’anatomie et de traits écophysiologiques foliaires), des facteurs endogènes (phénologie, organes végétaux) et les conditions de croissance. L’approche expérimentale a été orientée sur l’influence de certaines conditions de croissance sur la teneur en silice (défoliation, humidité, fertilité du substrat). Les résultats confirment l’influence de la défoliation et de la fertilité du substrat sur l’accumulation de la silice, mais soulignent bien la complexité de l’action de ces facteurs qui se traduit notamment par des différences de réponse entre espèces. Ces résultats suggèrent que les contradiction entre travaux publiés en ce qui concerne le caractère inductible ou non de l’accumulation de la silice sont dues pour partie à des interaction espèces*défoliation, et à une grande sensibilité des résultats aux conditions d’application de la défoliation. Les variations de la teneur en silice (intrinsèques et induites par les conditions de croissance) mises en relation avec les variations de traits structuraux et fonctionnels (surface foliaire spécifique, teneur en eau, anatomie foliaire, etc.) montrent des corrélations qui ne sont pas entièrement constantes au travers de tous les essais. Elles sont significativement positives avec les cendres solubles dans toutes les conditions de croissances examinées, mais négatives avec le carbone en condition de défoliation. Avec la teneur en eau, elles sont positives en conditions de défoliation, mais changent de signe en conditions de fertilisation phospho-azotée. Cette corrélation négative avec la teneur en eau est consistante à la fois dans les limbes et les gaines en comparaison interspécifique. Cette différence dans la structure des corrélations résulte à la fois des effets d’échantillonnage et l’étendue plus ou moins grande de la gamme des teneurs en silices balayées par les différentes espèces examinées. Pennisetum unisetum est la plus riche en silice et en sclérenchyme et qui pèse de façon disproportionnée dans l’analyse des corrélations. Les résultats n’apportent pas un soutien très clair à l’hypothèse selon laquelle la silice peut se substituer aux composés carbonés comme matériau de soutien. / The present study examines the variation of the silica accumulation of tropical grass species on the ecological and evolutionary point of view. The review of works examining the extent of the variation of the silica content in grasses identifies three groups of factors influencing the grass silicification, in particular the genetic factors (difference in the capacity of root absorption, anatomy and foliar ecophysiological features), endogenous factors (phenology, organs) and the growth conditions. The experimental approach focused the influence of certain conditions of growth on the silica content (defoliation, moisture, substrate fertility). The results confirm the influence of the defoliation and the substrate fertility on the silica accumulation, but underline well the complexity of the action of these factors which results in particular in differences in response between species. These results suggest that contradiction between published works with regard to the inducible character or not of the silica accumulation are due to some extent to the species*defoliation interaction, and a great sensitivity of the results to the conditions for application of defoliation. Variations of the silica content (intrinsic and induced by the growth conditions) relating to the variations of structural and functional characters (specific leaf area, water content, foliar anatomy, etc.) showed correlations which are not entirely constant through all the tests. They are significantly positive with soluble ashes under all the examined conditions, but negative with carbon in condition of defoliation. With the water content, they are positive in conditions of defoliation, but change sign in conditions of phospho-nitrogenized fertilization. This negative correlation with the water content is consistent at the same time in blades and sheaths in interspecific comparison. This difference in the structure of the correlations results at the same time from the effects of sampling and the more or less large extent of the range of the silica contents swept by the various examined species. Pennisetum unisetum is richest in silica and sclerenchyma and which weighs disproportionately in the analysis of correlations. The results do not give a very clear support for the assumption according to which silica can replace the carbonaceous compounds like material of support. / Doctorat en sciences agronomiques et ingénierie biologique / info:eu-repo/semantics/nonPublished

Abstract Fertility declines with advancing age and the number of couples seeking infertility treatment at an older age is constantly increasing. A top quality embryo is believed to have the highest potential for implantation and development into a child. A better understanding of the relative importance of patient and treatment characteristics and of embryo quality could help to optimise the existing therapeutic schemes and the safety of in vitro fertilisation/intracytoplasmic sperm injection (IVF/ICSI). In this work, databases of five Finnish infertility clinics were studied retrospectively. Data on treatments performed in the years 1994–2005 were collected. A total of 19,000 treatment cycles were analysed. Special attention was paid to the relative significance of the transfer of top quality embryos with regards to pregnancy, miscarriage, live birth and cost of treatment in the general IVF/ICSI patient population and in groups with expected poor outcome. The results showed that the transfer of a top quality embryo is associated with a better chance of pregnancy and live birth. However, it does not diminish the probability of miscarriage. Both low and high BMI increase the miscarriage rate. Advancing age and a positive history of previous miscarriages are also associated with a higher probability of miscarriage. In addition, the need for hormonal substitution in cases of frozen-embryo transfer is a risk factor of miscarriage, probably because of suboptimal endometrial function. Since the transfer of several embryos leads to multiple pregnancies, which are associated with a high risk of maternal and fetal complications, elective single embryo transfer (eSET) of a top quality embryo allows all additional good quality embryos to be frozen and transferred later in frozen-thawed embryo transfer cycles. The present work demonstrates that eSET is a safe treatment strategy at least until the age of 40. However, it might not be performed in women with fewer than four collected oocytes, since the prognosis might remain poor even if the response is improved in a following cycle. When eSET is applied routinely and on a large scale, it diminishes treatment costs while increasing the number of deliveries occurring at term, making IVF/ICSI at the same time safer and more affordable even to patients without access to reimbursed IVF treatment.

Imaging Time-of-Flight secondary ion mass spectrometry (ToF-SIMS) has been developed to perform 2D imaging and depth profiling of biological systems with micron or submicron scale lateral resolution, which can be attributed to the advent of polyatomic ion beam particularly C60+ and new concept of ToF-SIMS instrument, the J105 3D Chemical Imager (J105). These recent advances in ToF-SIMS have opened a new dimension for biological analysis. In this study, 2D and 3D imaging have been performed on two biological systems, Xenopus laevis (X. laevis) zygote/embryo and murine embryonic fibroblasts NIH 3T3 BXB-ER cells to explore the capability of ToF-SIMS to handle the biological samples with extreme topography and high resolution depth profiling of microdomains, which still represent major challenges for the ToF-SIMS. The study on X. laevis embryo explored the capability of ToF-SIMS to handle spherical samples (approx. 1-1.2 mm in diameter), identify lipid species in mixtures of lipid extraction from the zygotes and image of an intact embryo in 2D/3D during dynamic biological events, e.g., fertilisation and early embryo development. For the first time the J105 and conventional BioToF-SIMS instrument were employed for the study of developmental biology. The major classes of lipid were identified through multiple lipid assay in a single analytical run using ToF-SIMS. Topography effects of the embryo were assessed through imaging a single intact zygote/embryo that revealed secondary ions loss at the edge of the single cell. However, the topography effects on the mass resolution could be minimised using the J105. Moreover, in situ lipid profiling of the zygote revealed different lipid compositions and intensities on the membrane of the animal and vegetal hemispheres. Furthermore, high resolution imaging and depth profiling that performed on a single intact cell in a time course study visualised the egg-sperm fusion sites on the membrane of the zygote 10 min post-insemination and lipids arrangement on the membrane of the embryo through the early development stages. Subcellular signalling upon the fertilisation was also spatially located on the serial cryosections of a single zygote. With the NIH 3T3 BXB-ER cells, the study firstly adopted a finely focused C60+ beam to track morphological changes and rearrangement of subcellular organelle mitochondria (0.5-2 µm) in response to the activation of Raf/ERK (extracellular signal regulated kinase) pathway using the J105. The SIMS images of the unlabelled cells showed the shifting of membrane distribution and nuclei shrinking following Raf/ERK activation. The mitochondria fluorescence probe within the cells were located 3-dimensionally using confocal microscopy and ToF-SIMS, which revealed the distribution pattern of condensing in the two sides of the nuclei following the Raf/ERK activation. Coupled with scanning electron microscopy (SEM), the three imaging modes showed good agreement in cellular morphological changes and subcellular mitochondrial rearrangement without or following Raf/ERK activation, demonstrating an integrated approaching to study the biological processes at subcellular dimension.

This is a fascinating time of digital media and new technologies. They offer immersion and interaction and they challenge us, as creators, to work in alternative ways, create more space for the audience and develop our ideas across media while staying true to our artistic principles. During my research, I developed a body of work that includes films, VR, AR, film and stand up comedy as a way to investigate cross-fertilisation in the creative field between different formats, practices and individuals. / <p>This is the written part of the research and is supplementing the exposition in Research Catalogue.</p>

Philosophiae Doctor - PhD / Infertility is currently a serious problem that is escalating, not only in South Africa, but also worldwide. In Cape Town, a culturally diverse, urban community of approximately 1000 couples are referred to the Groote Schuur Hospital Infertility Clinic annually. Although infertility is primarily regarded as a medical condition, the treatments have emotional effects on infertile couples due to the recurring highs and lows that often accompany treatments. This study aimed to qualitatively explore and understand the emotional and psychological experiences of infertility and its treatments (specifically In Vitro Fertilisation and Embryo Transfer). Social constructionism is based on the premise that realities are not constructed in a vacuum but rather undergo a process whereby the subjective and inter-subjective experiences over time and through cultural processes come to be regarded as truths. These truths become internalised and function as lenses through which we see ourselves, compose and invent ourselves accordingly, making sense of what would otherwise have been chaotic and meaningless experiences. Additional aims were to examine women's experiences of infertility care whilst undergoing treatment and describe their experiences of coping with infertility and In Vitro Fertilisation and Embryo Transfer (IVF-ET). Semi-structured, in-depth individual interviews were conducted with 21 women presenting with primary infertility at a fertility clinic. This study utilised an ethnographic case study design. The results of the study suggested that women perceived themselves as not conforming to a dominant belief system that promotes motherhood as the most important role for women. The women described their 'failure' to fulfill socio-cultural expectations as emotionally turbulent. Some of the psychological responses to infertility included feelings of disappointment, shock, denial, devastation, anger, frustration, sadness, inadequacy, poor self-image and self-esteem. The women's personal accounts of their experiences of In Vitro Fertilisation and Embryo Transfer (IVF-ET) revealed that they found the treatment to be highly stressful, with emotional bouts of anxiety, nervousness, excitement and optimism. A psychological synopsis of infertility and IVF-ET is infertility and IVF-ET presents. The fmdings in this study suggest the need for the incorporation of presented. This diagrammatic representation shows the intensity of the emotional rollercoaster that psychosocial intervention into infertility management. Greater attention to the psychological and emotional repercussions of infertility treatment could lead to a more personalised approach which, in turn, would optimise patient satisfaction and also prepare couples for the demands of the program by informing them about better ways of coping.

Les productions laitières et de bovins de boucherie représentent un secteur important de l’agriculture. Le foin cultivé servant de base à l’alimentation des troupeaux couvre un peu plus de 40% des superficies en culture au Québec. La qualité du foin a un impact sur des déséquilibres nutritionnels comme l’hypomagnésémie et l’hypocalcémie chez la vache en lactation. L’influence de facteurs climatiques, pédologiques, de gestion et de fertilisation sur le rendement et la qualité du foin peut être décrite par des modèles linéaire et mixte (Mitscherlich); ce modèle permet de rendre compte des effets fixes qui affectent tous les échantillons de la même manière, et des effets aléatoires, spécifiques à chacun. L’objectif est d’élaborer un modèle de réponse du rendement en fourrage et de risque d’hypomagnésémie aux facteurs d’environnement et de gestion. Le modèle établit un lien entre le rendement, l’analyse minérale et texturale des parcelles où sont cultivées les plantes fourragères, les données climatiques recueillies lors des essais, comme les degrés-jours, le cumul et la diversité des précipitations, la fertilisation azotée, phosphorée et potassique, et le mélange fourrager. Les facteurs qui affectent le plus significativement à la hausse les rendements en fourrage sont les fertilisations azotée et phosphatée, une hausse du nombre de degrés-jours, une augmentation des précipitations, une diminution de la teneur en argile, et une diminution de la balance [Légumineuses / Dairy production and beef cattle farms form an important agricultural sector. Forage crops used to feed the cattle represent 40% of all the cultivated land in Quebec. Forage quality has an impact on nutritional disorders such as hypomagnesemia and hypocalcemia of lactating cows. The influence of climatic, soil, management and fertilization factors on the yield and quality of hay can be described by linear and mixed models (Mitscherlich); this model allows to account for fixed effects that affect all samples in the same way, and random effects, specific to each sample. The final goal is to develop a forage yield response and hypomagnesemia risk model for environmental and management factors. The model relates the yield, the mineral and textural analysis of the plots where the forage crops were grown, the climatic data collected during the tests, such as the degree-days, the accumulation and diversity of the precipitations, the nitrogen, phosphorus and potassium fertilization, and the forage mixture. The factors that most significantly affect forage yields are nitrogen and phosphate fertilization, an increase in degree-days, increased precipitation, a decrease in clay content, and a decrease in the balance [ Legumes