面為基階段在視覺處理歷程中扮演重要角色，面表徵是高於視網膜影像的視覺表徵，本研究目的在於探討以「面表徵」為選擇基礎之注意力運作。參考過去研究者所採用的面材料，本研究改為同時呈現二個交叉斜面並進行線索提示作業，以同面優勢效果作為面為基注意力運作之指標。 本研究分成四項實驗，每項實驗皆由兩個子實驗構成，此二個子實驗分別使用「外因性線索提示作業」與「內因性線索提示作業」探討面為基注意力的運作。實驗一利用上述「面」的設計及兩種提示作業，得同面優勢效果，反映面為基注意力的運作參與其中。實驗二目的在於排除注意力根據「可能目標的斜度」進行選擇之混淆，因此將面改為擁有相同斜度且互相平行的二個斜面。注意力若根據可能目標的斜度進行選擇，則無法得同面優勢效果。結果顯示在實驗二的兩種提示作業中，仍得同面優勢效果。實驗三目的在於排除可能目標因空間排列而形成簡單的知覺組織，繼而影響注意力分配之可能性。結果顯示在外因性線索提示作業下，仍得同面優勢效果；在內因性線索提示作業下，SOA需延長至500毫秒，才展現同面優勢效果。實驗四則進一步確認在不同SOA下，面為基注意力的運作情況，結果發現：在外因性線索提示作業下，SOA為500毫秒展現同面優勢效果；內因性線索提示作業下， SOA為1000毫秒下展現同面優勢效果。 綜合而言，在外因性線索提示作業與內因性線索提示作業下皆得到同面優勢效果。當可能目標難以群聚後，在長SOA時距下，依然展現同面優勢效果。因此本研究的結果，對於面為基注意力提供了直接的支持證據。 / Surface-based stage plays an important role in visual information process. Surface representation means the representation that goes beyond 2-D image representation. The purpose of this study is on the exploration of attentional selection which is based on surface representation. Referring to the surface material used before, this study adopted two interlacing slant surfaces structured by random-dot stereogram to test the effect of “same-surface advantage”. There are four experiments and each experiment includes two sub-experiments which are exogenous cuing task and endogenous cuing task, respectively. In Experiment 1, the same-surface advantage was revealed. In Experiment 2, the confounding of “slant” was ruled out and the same-surface advantage was still kept. In Experiment 3, we reduced the possibility that candidate targets group together to form simple perceptual organization and then influence the allocation of attention. After rearrange the spatial positions of candidate targets, attention cannot select the simple perceptual organization easily. In exogenous cuing task, same-surface advantage was still revealed. In endogenous cuing task, SOA should be prolonged to 500ms, and it shows same-surface advantage. Furthermore, in Experiment 4, we manipulate three kinds of SOA and confirm the operation of surface-based attention. We found that in exogenous cuing task, SOA should be prolonged to 500ms, and it shows same-surface advantage.In endogenous cuing task, SOA should be prolonged to 1000ms, and it shows same-surface advantage. In conclusion, it shows same-surface advantage in exogenous cuing task and endogenous cuing task. When candidate cannot group together to be selected easily, SOA should be prolonged to longer, and it still shows same-surface advantage. The results provide the direct support evidences of surface-based attention.

Les molécules du complexe majeur d'histocompatibilité de classe II (CMH II) sont exprimées exclusivement à la surface des cellules présentatrices d'antigènes et servent à stimuler les cellules CD4+ initiant une réponse immunitaire. Le chargement peptidique sur HLA-DR se produit dans les endosomes tardifs et les lysosomes sous l'action de HLA-DM. Cette molécule de classe II non-classique enlève les fragments peptidiques de la chaîne invariante (Ii) restés associés aux molécules de classe II (CLIP) et édite leur répertoire d'antigènes présentés. En utilisant une forme mutante de HLA-DM (HLA-DMy) qui s'accumule à la surface plasmique, nous avons observé que HLA-DMy augmente les chargements de peptides exogènes et aussi la réponse des cellules T en comparaison avec HLA-DM sauvage. Il a été démontré que des molécules chimiques, comme le n-propanol, pouvait avoir le même effet que HLA-DM en remplaçant les peptides associés aux molécules de classe II de la surface cellulaire. De plus, HLA-DMy et le n-propanol ont présenté un effet additif sur la présentation de peptides exogènes. Certaines protéines de la voie endocytique, comme HLA-DR, HLA-DM, HLA-DO et Ii sont ciblés aux compartiments multivésiculaires (MVB) et peuvent être ciblées aux exosomes. Suite à une fusion entre les MVB et la membrane plasmique, les exosomes sont relâchés dans le milieu extracellulaire. Nous avons déterminé que le motif tyrosine de HLA-DMβ et son interaction avec HLA-DR n'affectaient pas le ciblage aux exosomes, sauf la molécule HLA-DO. Cette étude nous a permis de démontrer que HLA-DMy augmente la quantité de peptides exogènes chargés sur les CPA et que HLA-DM et HLA-DMy sont incorporés dans les exosomes. / Major histocompatibility class II (MHC II) molecules are expressed exclusively on the surface of antigen presenting cells and serve to stimulate CD4+ cells to initiate an immune response. Peptide loading on MHC II molecules occurs in late endosomal and lysosomal compartments by the catalytic action of HLA-DM. This non-classical class II molecule removes class-II-associated invariant-chain peptide (CLIP) from class II molecules and edits their repertoire of antigenic peptides loaded. Using a mutant form of HLA-DM (HLA-DMy) that is targeted to the plasma membrane, we observed in the case of HLA-DMy, there is an increase of the loading of exogenous peptides and also significantly increased T cell response in comparison with HLA-DM wild-type. It was found that some chemical molecules, like n-propanol, could mimic the effect of HLA-DM by removing peptides from cell surface class II molecules. Interestingly, HLA-DMy and n-propanol seem to have an additive effect on the exogenous peptide loading. Some proteins of the endosomal pathway, like HLA-DR, HLA-DM, HLA-DO and Ii are targeted to microvesicules-containing compartments called MVB and they can be introduced into exosomes. Following the fusion between MVB and plasma membrane, exosomes are released in extracellular environment. We have determined that tyrosine motif of HLA-DMβ and interaction with HLA-DR does not affect HLA-DM targeting to exosomes, except for the HLA-DO molecule. In conclusion, we showed that HLA-DMy increases the quantity and the quality of exogenous peptides loading on APC and HLA-DM and HLA-DMy are incorporated to exosomes.

Chez la drosophile, l’activation du récepteur Toll menant à une réponse antimicrobienne peut se faire par deux voies différentes. Ces deux voies sont activées soit par des récepteurs dédiés, les Pattern Recognition Receptors (PRRs) reconnaissant des motifs moléculaires microbiens, soit par la coupure d’une molécule circulante appelée Perséphone par des protéases microbiennes extrêmement diverses sécrétées pendant une infection. Cependant, le mécanisme par lequel Perséphone est activée demeurait ambigu. Nous avons identifié une région unique dans Perséphone fonctionnant comme un appât pour les protéases exogènes indépendamment de leur origine, type ou spécificité. Une coupure dans cette région constitue la première étape d’une activation séquentielle de Perséphone ; elle permet de recruter la cathepsine circulante 26-29-p, qui va générer la forme active de Perséphone.Ces travaux montrent comment un récepteur de l’immunité innée, Perséphone, peut être activé par un signal de danger, en l’occurrence des enzymes microbiennes, et non par la détection de motifs moléculaires qui peuvent être présents dans la flore microbienne hébergée par les animaux. / In Drosophila, the antimicrobial response against infections can be triggered by two different extracellular mechanisms that both lead to the activation of the Toll receptor. These two mechanisms are activated either by the recognition of specific microbial determinants by Pattern Recognition Receptors (PRRs), or by the cleavage of the circulating serine protease Persephone by a wide range of microbial proteases secreted during infections. However, the molecular mechanism underlying Persephone activation remained ambiguous. We identified a unique region in Persephone pro-domain that functions as a bait for exogenous proteases independently of their origin, type or specificity. Cleavage of Persephone in this bait region constitutes the first step of a sequential activation and licenses the subsequent maturation of Persephone to the endogenous circulating cysteine cathepsin 26-29-p. Our data establish Persephone itself as an immune receptor able to sense a broad spectrum of microbes through the recognition of danger signals rather than molecular patterns.

L’utilisation des Produits Résiduaires Organiques (PRO) par l’agriculture peut permettre de substituer une partie des engrais minéraux et augmenter les niveaux de matière organique des sols. Elle peut également générer des pollutions azotées via la lixiviation de nitrate ou des émissions gazeuses. Mieux connaitre le devenir du carbone (C) et de l’azote (N) après applications de PRO sur les sols agricoles contribue à améliorer les bénéfices de cette pratique et à en limiter les impacts environnementaux. Cette thèse a pour objectif: (i) de prédire les dynamiques du C et du N en cas d’applications de PRO sur les sols agricoles, (ii) d’étudier les effets de scenarios d’apports de PRO sur les stocks de carbone dans les sols, la substitution des engrais azotés et les pollutions azotées dans le contexte du territoire de la Plaine de Versailles, en prenant en compte la diversité des sols, de leurs teneurs en C et des successions culturales, (iii) d’améliorer ces bénéfices à l’échelon du territoire via une distribution optimale des PRO. Le modèle CERES-EGC a été utilisé pour simuler les effets de 13 ans d’apports de PRO sur les dynamiques de C et de N dans le système sol-plante-atmosphère de l’expérimentation QualiAgro, située au cœur du territoire d’étude. Le sous-modèle NCSOIL a été paramétré à partir de cinétiques de minéralisation de C et N mesurées en conditions contrôlées de laboratoire. Le transfert de ces paramètres dans CERES-EGC a permis de simuler correctement les évolution des stocks de carbone dans les sols, les rendements et les prélèvements de N par les cultures ainsi que l’évolution des stocks de N minéral dans les sols. Les dynamiques de minéralisation de C et N des 18 PRO disponibles sur le territoire ont été déterminées. NCSOIL a été paramétré à partir des caractéristiques analytiques et des résultats de fractions biochimiques des PRO. Les types de sol du territoire n’ont pas impacté significativement le paramétrage. Les PRO ont été classés selon 4 types : (1) composts stables, (2) composts moins matures restant plus réactifs et les fumiers stables, (3) des fumiers très réactifs correspondant à des fumiers de chevaux, (4) des PRO très réactifs tels que des boues et des fientes pouvant plutôt être utilisés comme fertilisants. De nombreux scenarios d’apport de PRO, contraints par les flux de phosphore et de N apportés, ont été simulés sur 20 ans dans tous les contextes de sols, successions culturales et teneurs en C organique des sols du territoire. Le type de sol a impacté le plus le stockage de C et les lixiviations de nitrate tandis que les successions culturales étaient prépondérantes sur la substitution des engrais. Des composts ont permis de stocker 1.1 t C ha- 1 an-1 allant jusqu’63% du C apporté. Des substitutions de 74 kg N ha-1 an-1 ont été atteintes avec une boue mais aussi un compost en prenant en compte la substitution des engrais liée aux augmentations de matière organique dans les sols. La substitution des engrais a pu atteindre plus de 90% du N apporté par les PRO, ceci étant lié aux arrières-effets sur le stockage de matière organique dans les sols et dépendant des hypothèses de calcul de la substitution des engrais azotés. Un modèle d’optimisation a été développé pour sélectionner les scenarios d’apports de PRO pour chaque ilot du territoire (sol x succession de culture x teneur en C organique initiale x surface) tenant compte de la disponibilité des PRO et avec pour objectif de maximiser le stockage de C ou les substitutions en engrais azotés ou de minimiser la lixiviation de nitrate au niveau du territoire. En apportant préférentiellement les PRO les plus stables sur les sols à fort potentiel de stockage de C (fortes teneurs en argile et calcaire), jusqu’à 0.47 t C ha-1 an- 1 pourrait être stocké. En appliquant préférentiellement les PRO fertilisants sur les successions à maïs, et les PRO amendants sur les successions à colza jusqu’à 53 kg N ha-1 an-1 de N de synthèse pourrait être économisés. / The use of Exogenous Organic Matter (EOM) in agriculture could be an efficient way to substitute mineral fertilisation and increase soil organic matter (SOM) enhancing soil fertility and storing carbon (C). It could also cause nitrogen (N) pollutions such as nitrate leaching and gas emissions. Better understanding of C and N fate after EOM applications on cropped soils would allow improving these benefits while limiting environmental impacts. This thesis aims at: (i) predicting EOM impacts when applied on cropped soils, (ii) studying the effects of various scenarios of EOM applications in terms of C storage, synthetic N saving and N pollutions in the context of the Plain of Versailles region (221 km²) and taking into account soil diversity, crop successions and soil organic C contents, (ii) studying the potential for improving these benefits at the regional scale with an optimal distribution of EOM. The CERES-EGC crop model was used to simulate the effects of repeated applications of EOM over 13 years on both soil C and N dynamics in the soil-crop-water-air system of the long-term field experiment QualiAgro located within the region. The sub-model NCSOIL was parameterised from C and N mineralisation kinetics of EOM measured in laboratory conditions. When transposing the parameters into the CERES-EGC model, C storage at the field scale was well simulated, together with crop N uptake and yields, as well as soil mineral N contents. The kinetics of C and N mineralisation of the 18 EOM available in the region were used along with EOM biochemical fractionations for parameterising the NCSOIL model. The soil type did not significantly change EOM parameters. Four groups of EOM were distinguished based on their C and N dynamics: (i) stable composts, (2) more reactive and less mature composts and stable manures, (3) manures with reactive OM corresponding to horse manures and (4) very reactive EOM as sludges, litters that should be used as fertilisers. Numerous scenarios of EOM applications, constrained on the phosphorus and N quantities they bring (and limiting the input in trace elements), were simulated for 20 years in all regional contexts of soil, crop successions and soil organic C contents. The soil type was the main factor controlling C storage and N leaching while it was crop successions for N saving. Some composts allowed C storage up to 1.1 t C ha-1 yr -1 reaching 63% of C applied. N saving of 74 kg N ha-1 yr -1 were possible with a dried sewage sludge and a compost. N substitution could reach more than 90% of N applied with EOM, these high percentages being related with the indirect effect of EOM on soil OM and the hypothesis made for N substitution An optimisation model was developed to select EOM application scenario for each crop plot (soil x crop succession x initial soil OC content x area) accounting for EOM availability in the region with the objectives of maximising C storage or synthetic N saving or minimising N leaching at the regional scale. Applying preferentially the most stable EOM on soils with the highest potential for C storage i.e. with the highest calcareous and clay contents, up to 0.47 t C ha-1 yr-1 could be stored. Applying preferentially fertilising EOM on crop succession with maize and amending EOM on succession with rapeseed, up to 53 kg N ha-1 yr -1 could be saved.

La evidencia sobre el efecto de las nitrosaminas (NA) sobre el cáncer gástrico (CG) es insuficiente. El objetivo fue evaluar el efecto de las NA (exógenas y endógenas ) y sus alimentos fuente sobre el riesgo de CG. El estudio incluyó 521.457 individuos del estudio EPIC (European prospective Investigation into Cancer and Nutrition) y 314 casos incidentes de C. Estimamos la exposición exógena aplicando una tabla de composición que desarrollamos para tal fin. Para estimar las NA endógenas creamos un índice de formación endógena (ENOC) basado en datos previamente publicados. Observamos un efecto de carnes rojas, procesadas y ENOC restringida a la región distal y en individuos positivos el Helicobacter Pylori. No se observó ningún efecto de las NA exógenas sobre el CG. Se observo una interacción entre ENOC y vitamina C. En resumen, el riesgo de CG se ve afectado por la interrelación entre ENOC, Hp y vitamina C. / Evidence relating nitrosamines (NA) and gastric cancer (GC) risk is not conclusive. The risk of GC associated with meat and NA intake and endogenous formation of NA (ENOC) was investigated in the European Prospective Investigation into Cancer and Nutrition with a population of 521.457 subjects and 314 incident cases of GC. To estimate NA intake we developed a food composition database. An index of ENOC was created using information from previous published studies. The risk of CG increases with intake of red and processed meat and ENOC restricted to non-cardia site and mainly in Helicobacter pylori (Hp) infected subjects. There were no association between NA intake and GC. We observed an interaction between ENOC and vitamin C. In summary, Hp infection, vitamin C and ENOC play an important role on GC risk.

Les molécules du complexe majeur d'histocompatibilité de classe II (CMH II) sont exprimées exclusivement à la surface des cellules présentatrices d'antigènes et servent à stimuler les cellules CD4+ initiant une réponse immunitaire. Le chargement peptidique sur HLA-DR se produit dans les endosomes tardifs et les lysosomes sous l'action de HLA-DM. Cette molécule de classe II non-classique enlève les fragments peptidiques de la chaîne invariante (Ii) restés associés aux molécules de classe II (CLIP) et édite leur répertoire d'antigènes présentés. En utilisant une forme mutante de HLA-DM (HLA-DMy) qui s'accumule à la surface plasmique, nous avons observé que HLA-DMy augmente les chargements de peptides exogènes et aussi la réponse des cellules T en comparaison avec HLA-DM sauvage. Il a été démontré que des molécules chimiques, comme le n-propanol, pouvait avoir le même effet que HLA-DM en remplaçant les peptides associés aux molécules de classe II de la surface cellulaire. De plus, HLA-DMy et le n-propanol ont présenté un effet additif sur la présentation de peptides exogènes. Certaines protéines de la voie endocytique, comme HLA-DR, HLA-DM, HLA-DO et Ii sont ciblés aux compartiments multivésiculaires (MVB) et peuvent être ciblées aux exosomes. Suite à une fusion entre les MVB et la membrane plasmique, les exosomes sont relâchés dans le milieu extracellulaire. Nous avons déterminé que le motif tyrosine de HLA-DMβ et son interaction avec HLA-DR n'affectaient pas le ciblage aux exosomes, sauf la molécule HLA-DO. Cette étude nous a permis de démontrer que HLA-DMy augmente la quantité de peptides exogènes chargés sur les CPA et que HLA-DM et HLA-DMy sont incorporés dans les exosomes. / Major histocompatibility class II (MHC II) molecules are expressed exclusively on the surface of antigen presenting cells and serve to stimulate CD4+ cells to initiate an immune response. Peptide loading on MHC II molecules occurs in late endosomal and lysosomal compartments by the catalytic action of HLA-DM. This non-classical class II molecule removes class-II-associated invariant-chain peptide (CLIP) from class II molecules and edits their repertoire of antigenic peptides loaded. Using a mutant form of HLA-DM (HLA-DMy) that is targeted to the plasma membrane, we observed in the case of HLA-DMy, there is an increase of the loading of exogenous peptides and also significantly increased T cell response in comparison with HLA-DM wild-type. It was found that some chemical molecules, like n-propanol, could mimic the effect of HLA-DM by removing peptides from cell surface class II molecules. Interestingly, HLA-DMy and n-propanol seem to have an additive effect on the exogenous peptide loading. Some proteins of the endosomal pathway, like HLA-DR, HLA-DM, HLA-DO and Ii are targeted to microvesicules-containing compartments called MVB and they can be introduced into exosomes. Following the fusion between MVB and plasma membrane, exosomes are released in extracellular environment. We have determined that tyrosine motif of HLA-DMβ and interaction with HLA-DR does not affect HLA-DM targeting to exosomes, except for the HLA-DO molecule. In conclusion, we showed that HLA-DMy increases the quantity and the quality of exogenous peptides loading on APC and HLA-DM and HLA-DMy are incorporated to exosomes.

The current understanding of lactate metabolism in fish is based almost entirely on interpretation of concentration measurements that cannot be used to infer changes in flux. Moreover, the transporters regulating these fluxes have never been characterized in rainbow trout. My goals were: (1) to quantify lactate fluxes in rainbow trout under normoxic resting conditions, during acute hypoxia, and exercise by continuous infusion of [U-14C] lactate; (2) to determine lactate uptake capacity of trout tissues by infusing exogenous lactate in fish rest and during graded exercise, and (3) to clone monocarboxylate transporters (MCTs) and determine the effects of exhausting exercise on their expression. Such information could prove important to understand the mechanisms underlying the classic “lactate retention” seen in trout white muscle after intense exercise. In normoxic resting fish, the rates of appearance (Ra) and disappearance (Rd) of lactate were always matched (~18 to 13 µmol kg-1 min-1), thereby maintaining a low baseline blood lactate concentration (~0.8 mM). In hypoxic fish, Ra lactate increased from baseline to 36.5 µmol kg-1 min-1, and was accompanied by an unexpected 52% increase in Rd reaching 30.3 µmol kg-1 min-1, accounting for a rise in blood lactate to 8.9 mM. In exercising fish, lactate flux was stimulated > 2.4 body lengths per second (BL s-1). As the fish reached critical swimming speed (Ucrit), Ra lactate was more stimulated (+67% to 40.4 μmol kg-1 min-1) than Rd (+41% to 34.7 μmol kg-1 min-1), causing an increase in blood lactate to 5.1mM. Fish infused with exogenous lactate stimulated Rd lactate by 300% (14 to 56 μmol kg-1 min-1) during graded exercise, whereas the Rd in resting fish increased by only 90% (21 to 40 µmol kg-1 min-1). Four MCT isoforms were partially cloned and characterized in rainbow trout: MCT1b was the most abundant in heart, and red muscle, but poorly expressed in gill and brain where MCT1a and MCT2 were prevalent. MCT4 was more expressed in the heart. Transcript levels of MCT2 (+260%; brain), MCT1a (+90%; heart) and MCT1b (+50%; heart) were stimulated by exhausting exercise. This study shows that: (i) the increase in Rd lactate plays a strategic role in reducing the lactate load imposed on the circulation. Without this response, blood lactate accumulation would double; (ii) a high capacity for lactate disposal in rainbow trout tissues is elicited by the increased blood-to-tissue lactate gradient when extra lactate is administered; and (iii) rainbow trout may be unable to release large lactate loads rapidly from white muscle after exhausting exercise (lactate retention) because they poorly express MCT4 in white muscle and fail to upregulate its expression during exercise.

Ghana has experienced a remarkable degradation and depletion of its forest resources over the last 100 years. This process has undermined the socio-economic and socio-cultural importance of the forests for millions of rural people who depend on the resource to support their livelihood. Many rural households have over the past three decades developed strategies to minimize the effects of forest depletion on their livelihood. The establishment of smallholder forest plantation on agricultural land has emerged as an important form of land-use for households to diversify their sources of income and also improve their socio-economic well-being. The main objective of the study was to identify and analyze the endogenous and exogenous factors inducing farm household’s decision to establish farm forest plantation and to analyze its financial contribution to household’s income and livelihood strategies. The study involved a survey of 280 randomly selected farm households from five communities in the Offinso district in Ghana. The multi-stage stratified random sampling technique was used to select as many as 165 households with farm forest plantation as well as 115 without farm forest plantation. A mixture of tools including semi-structured questionnaire, focus group discussions, wealth ranking, forest inventory and market surveys were used to collect the required data. Results from logistic regression analysis revealed that the age of the household head, the number of years of education of the household head, the amount of household labor, the size of household landholding, the ownership of permanent land, the availability of non-agricultural land and household’s participation in past forest plantation development projects are the most important endogenous factors influencing the farm household’s decision to establish farm forest plantation. On the other hand, exogenous factors such as the availability of market and buyers for farm forest products and farm household’s satisfaction with market prices for farm forest products positively influenced the household’s decision to establish farm forest plantation. Prohibitive rules and regulations relating to the harvesting of trees and transportation of timber from private lands and uncertainty in tree tenure as a result of ambiguous policy framework, however, negatively influenced the decision to establish smallholder forest plantation on their agricultural land. The results from household income portfolio analysis show that cash income from selling farm forest products contributed an average of $273.6 to total household’s income in one agricultural season. This amount accounted for 17.6% of total household’s income and represented the second most important source of income after agriculture. The profitability of different land-uses practiced by the households was analyzed using a conventional economic method (Net Present Value). The results from a comparative financial analysis show that the establishment of teak plantation on agricultural land inter-cropped with food crops is the most profitable form of land use for the households compared to pure teak plantation and maize-plantain cultivation. The results of the study underscore the potential contribution of smallholder farm forest plantation to increase the overall household’s income and thereby improve household’s well-being. / Ghana hat während der letzten 100 Jahre eine bemerkenswerte Degradation und Verminderung seines Waldvorkommens erlebt. Dieser Prozess hat die sozio-ökonomische und sozial-kulturelle Bedeutung des Waldes als Einkommensquelle zur Unterstützung des Lebensunterhalts für Millionen ländlicher Einwohner geschwächt. Während der letzen 30 Jahre haben viele Kleinbauern Haushalte Strategien entwickelt um den Effekt, den die Verminderung des Waldvorkommens auf ihren Lebensunterhalt hat, zu minimieren. Die Anlage kleinflächiger Forstplantagen auf Ackerland hat sich dabei als wichtige Form der Landnutzung erwiesen, da sie eine Einkommensquelle zusätzlich zu den vorhandenen bedeuten. Sie haben das Potential, die sozio-ökonomiche Situation der Bevölkerung zu verbessern. Ziel der Studie war die Identifizierung von internen und externen Faktoren, die bedeutend zur Entscheidung von Haushalten über die Errichtung kleinflächiger Forstplantagen beitragen. Desweiteren sollten der finanzielle Beitrag der Forstplantagen zum Einkommen und zu Strategien der Kleinbauern analysiert werden. Für die Sudie werden Datensätze von 280 zufällig ausgewählten landwirtschaftlichen Haushalten aus fünf Gemeinden im Offinso Distrikt in Ghana erfasst. Die mehrstufig aufgebaute zufällige Auswahltechnik wurde benutzt, um die 165 Haushalte mit Forstplantagen und 115 Haushalten ohne Forstplantagen für die Studie auszuwählen. Mehrere Instrumente, wurden genutzt um die benötigten Daten zu sammeln darunter vor allem semi-strukturierte Befragungen, fokusierte Gruppendiskussionen, Wohlstandsranking der Haushalte und eine Forstinventur. Ergebnisse einer logistischen Regressionsanalyse ergaben, dass das Alter des Haushaltsvorstands, die Anzahl der Ausbildungsjahre des Haushaltsvorstands, die Anzahl der im Haushalt vorhandenen Arbeitskräfte, die Größe des dem Haushalt zur Verfügung stehenden Ackerlandes, das Eigentum an Ackerland, verfügbare nicht-landwirtschaftlich nutzbare Flächen und die Teilnahme der Haushalte an Projekten zur Forstplantagenentwicklung die wichtigsten internen Faktoren für die Entscheidung der Kleinbauern zur Errichtung von kleinflächiger Forstpantagen darstellen. Andererseits beeinflussten externe Faktoren wie das Vorhandensein von Markt und Käufern für Produkte der Forstplantagen und die Zufriedenheit der Haushalte mit den gebotenen Marktpreisen für diese Produkte die Entscheidung der Kleinbauern zur Errichtung von Forstplantagen positiv. Demgegenüber beeinflussten Verbote und einschränkende Regelungen zur Ernte und zum Transport von Bäumen auf Privatland und die Unsicherheit bezüglich des Eigentums an den Bäumen als Ergebniss unklarer politischer Vorgaben die Entscheidung zur Errichtung von kleinflächiger Forstplantagen auf Ackerland negativ. Das Ergebniss der Analyse verschiedene Haushaltseinkommensquellen zeigt, dass das Jahreseinkommen der Haushalte mit Forstplantagen höher ist als das der Haushalte ohne Forstplantagen. Der Beitrag zum Jahreseinkommen aus dem Verkauf von Produkten der kleinflächiger Forstplantagen betrug im Durchschnitt 273,6 USD in einer landwirtschaftlichen Saison. Dies entsprach 17,6 % des gesamten Haushaltseinkommens und stellte somit die zweitwichtigste Einkommensquelle nach der Landwirtschaft dar. Die Rentabilität der verschiedenen Landnutzungsarten wurde mit der Kapitalwertmethode (Net Present Value) ermittelt. Diese vergleichende Analyse zeigte, dass kleinflächiger Forstplantagen auf Agrarland bei gleichzeitigem Anbau von Nahrungsmittel die profitabelste Art der Landnutzung für die Haushalte im Vergeich zu ausschließlichem Teakanbau und zum Anbau von Mais mit Kochbanane ist. Die Ergebnisse der Studie unterstreichen das Potential kleinflächiger Forstplantagen, einen Beitrag zur Steigerung des gesamten Haushaltseinkommens und zur Verbesserung des Lebensstandards der Haushalte leisten zu können.

The TGFβ family of cytokines are potent signalling molecules that regulate tissue development, inflammation and immunity. Previous studies in mice with a null mutation in the Tgfb1 gene (TGFβ1-/- mice) implicate a key role for TGFβ1 in male reproductive function. These mice show profound infertility due to an inability to copulate successfully, associated with reduced testosterone and sperm production. The focus of this project was to 1) further characterize mechanisms underpinning reproductive deficiency in male TGFβ1-/- mice, 2) identify a reliable physiological marker of TGFβ1 availability in vivo, and 3) to determine whether exogenous TGFβ1 administration influences TGFβ1 availability and restores fertility. To investigate the causes of unsuccessful copulation by TGFβ1-/- mice, penis morphometry was examined. Penile organ structure, as assessed by scanning electron microscopy, was comparable between genotypes however a superfluous epidermal covering that impeded penile spine protrusion was evident in TGFβ1-/- mice. The epidermal covering was not due to increased epithelial cell proliferation, as measured by Brdu labelling and immunohistology. Behavioural observations of erectile activity showed that TGFβ1-/- mice achieved spontaneous erections albeit at reduced frequency compared to TGFβ1+/+ mice. The efficacy of exogenous TGFβ1 replacement was evaluated by first identifying measures of in vivo TGFβ1 availability and/or function and selecting an effective route of administration. Serum TGFβ1 and testosterone levels were reliable discriminators of TGFβ1 genotype. Gene expression and phagocytic function of peritoneal macrophages revealed no differences between genotypes. Exogenous sources of TGFβ1 for replacement studies included colostrum, naturally occurring in breast milk and recombinant human latent TGFβ1 (rhLTGFβ1). Colostrum did not increase circulating levels and rhTGFβ1 injection caused only transient elevation of serum levels. Thus mini-osmotic pumps were used to deliver a constant supply of cytokine to TGFβ1-/- mice. The fertility status of TGFβ1-/- mice receiving exogenous TGFβ1 was investigated. Reproductive behaviour in response to normal receptive female mice was assessed twice during treatment, on day 7 and day 14. Blood, liver and reproductive tissues were collected at sacrifice. Circulating TGFβ1 was increased in TGFβ1 treated TGFβ1-/- mice above TGFβ1-/- control levels, although this did not affect circulating testosterone. Erectile activity and sperm production were unchanged. Videotaping behaviour with estrous females revealed that the TGFβ1+/+ mice successfully mounted and intromitted, unlike the TGFβ1-/- controls. The TGFβ1-/- mice receiving exogenous TGFβ1 displayed moderately enhanced mounting and intromission behaviour although this remained less frequent than in the TGFβ1+/+ controls. Ejaculation behaviour was not observed in any TGFβ1-/- mice regardless of TGFβ1 replacement, compared to TGFβ1+/+ controls where >90% mice displayed ejaculated. Modest improvement in the copulation activity of the TGFβ1-/- mice receiving exogenous TGFβ1 suggests that systemic TGFβ1 availability can influence reproductive performance in male TGFβ1-/- mice. However since fertility was not restored, locally produced TGFβ1 in the reproductive tract and/or hypothalamic pituitary axis are also implicated in regulating fertility. These findings advance our knowledge of the role of the TGFβ1 cytokine in male reproductive physiology and may have relevance for devising new treatments for infertility and erectile dysfunction in men. / Thesis (Ph.D.) - University of Adelaide, School of Paediatrics and Reproductive Health, 2008

This dissertation is divided into six chapters, as foHows: Chapter 1 of this dissertation discusses the growing significance of FDI for developing countries. It compares FDT in developed and developing countries and analyses recent evidence ofFDI flows to developing countries. Chapter 2 analyses the (endogenous and exogenous) detenninants ofFDI flows into developing countries. Chapter 3 discusses the importance of FDI flows, which are essential for new investments or for financing fortuitous deficits in host countries, and looks at the adjustment mechanisms for the equilibrium of the balance of payments. Chapter 4 gives attention to FDI flows, the liberalisation of financial markets and the financial account of the balance of payments in developing countries in providing more opportunities and mechanisms for development and economic growth. Finally, chapter S examines and compares FDI flows tu South Africa and Angola - the biggest FDI recipients on the African continent. / Economics / MCom (Economics)