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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Essays on nursery labor, sales contracts, and price discovery

Li, Cheng 18 March 2013 (has links)
Oregon's nursery and greenhouse industry has ranked the first in the State's agricultural for 18 years. The majority of nursery sales from the Pacific Northwest come from Oregon. Due to data limitations, empirical study of the Oregon nursery industry is rare. The present dissertation consists of three essays that analyze the demand and supply of inputs and outputs and the relationship between producers and retailers in the Oregon nursery industry. Chapter 2 identifies the major factors affecting farm labor supply and demand and evaluates their relative importance in the Oregon nursery industry from 1991 to 2008. Empirical results show that border control effort doesn't have an influential role in labor supply, while the Oregon and Mexican minimum wage do. It is because of the substantial gap between the U.S. and Mexican economies, reflected for an example in the minimum wage gap, which attracts a continual flow of immigrants. Risk of border apprehension is not great enough to prevent the flow. Increases in Oregon minimum wage is more effective than border apprehension policies in boosting the average wage and in reducing the number of hours that illegal immigrants work in the nursery sector. Chapter 3 investigates producers' and retailers' choices of, and reactions to, various contract types in the Oregon nursery industry from 2005 to 2010. As new and fast-growing retailers in the industry, big-box stores are less likely than independent retailers to make pre-order contracts with the producer. However, once a pre-order contract is chosen, big-box stores demand more days of pre-order interval than independent retailers do. Transactions with independent retailers exhibit – on average over the sample range – scale economies and scope diseconomies. Boosting per-transaction revenue scale and the number of species sold to big-box stores enhances transaction efficiency. Chapter 4 examines the interaction between supply and demand in Oregon nursery products. The result indicates that the production and transaction costs are major drivers on the supply side, while transportation costs and consumer demand for nursery products play important roles on the demand side. At the genus level, the supply elasticities of coniferous plants are larger than those of deciduous plants, which in turn are higher than those of flowering plants. The demand elasticities are the lowest in coniferous trees followed by deciduous plants, then flowering plants. Price discounts on plants with high demand elasticities would significantly boost sales and enlarge the market, while those on plants with low demand elasticities would have less sales impact. Empirically, patenting seems to bring no direct signs of greater profitability. The wholesale nursery may wish to reconsider the pricing and marketing policies of its patented plants to differentiate them more effectively from its non-patented plants. / Graduation date: 2013
102

Ανάλυση φυσικών πληθυσμών της μεσογειακής μύγας Ceratitis Capitata : διερεύνηση της σχέσης γενότυπου και των ξενιστών της με τη χρήση μικροδορυφορικών δεικτών

Οικονόμου, Αικατερίνη 04 December 2008 (has links)
Η μεσογειακή μύγα αποτελεί το κύριο παράσιτο πολλών καλλιεργούμενων φρούτων προκαλώντας ετησίως μεγάλες καταστροφές σε γεωργικές καλλιέργειες. Η μελέτη του εντόμου τόσο σε γενετικό όσο και σε πληθυσμιακό επίπεδο μπορεί να συμβάλλει σημαντικά στην ανάπτυξη ή και τη βελτίωση αποτελεσματικών και φιλικών προς το περιβάλλον μεθόδων ελέγχου. Οι μικροδορυφόροι είναι απλές επαναλήψεις ενός νουκλεοτιδικού μοτίβου που αποτελείται 1-6 ζεύγη βάσεων. Αποτελούν πολύ χρήσιμους γενετικούς δείκτες διότι είναι άφθονοι και διάσπαρτοι στο γονιδίωμα των ευκαρυωτκών οργανισμών. Επιπλέον είναι υψηλά πολυμορφικοί, κληρονομούνται ως συνυπερέχοντες Μεντελικοί δείκτες και αναλύονται εύκολα μέσω PCR, χαρακτηριστικά που τους καθιστούν πολύτιμα εργαλεία για πληθυσμιακές και εξελικτικές μελέτες. Από τους μικροδορυφορικούς δείκτες που αναπτύχθηκαν στο εργαστήριό μας, επιλέχθηκαν 10 με βάση το βαθμό πολυμορφισμού που έδειξαν σε εργαστηριακά στελέχη. Οι δείκτες αυτοί χρησιμοποιήθηκαν στην ανάλυση 481 ενηλίκων ατόμων που προέρχονταν από 19 διαφορετικά δείγματα φρούτων που συλλέχθηκαν από εννέα διαφορετικές περιοχές της Δυτικής Ελλάδας και της Βόρειας Πελλοπονήσου. Η γενοτυπική ανάλυση πραγματοποιήθηκε με ηλεκτροφόρηση των προϊόντων της PCR για κάθε γενετικό δείκτη σε πήκτωμα πολυακρυλαμιδίου και επακόλουθη αυτοραδιογραφία. Η στατιστική επεξεργασία των αποτελεσμάτων, με τη βοήθεια υπολογιστικών προγραμμάτων αποκάλυψε σημαντική γενετική διαφοροποίηση μεταξύ των δειγμάτων, που αποδίδεται εκτός των άλλων παραγόντων (κλιματολογικές συνθήκες, γεωγραφική προέλευση) στο είδος του ξενιστή. / C. capitata, is the main pest of many cultivable fruits and responsible for a significant loss in annual products, resulting in great economic damage. Studies on the genetic and population analysis will make a contribution towards the development or the improvement of environmental friendly control methods. Microsatellites are tandem simple sequence repeats of short (1-6) nucleotide motifs. They are very important genetic markers because they are dispersed and abundant in most eukaryotic genomes. They are highly polymorphic, inherited as co-dominant Mendelian markers and easily scored by PCR. Consequently, they have become one of the most popular molecular markers with application in many genetic studies, including genetic analysis of natural populations and evolutionary studies. From the available microsatellites in our laboratory, were selected ten (10), based on their polymorphism in laboratory strains. They were used for the screening of 481 adult flies in the medfly, collected from nineteen (19) different samples of fruits from nine (9) different areas in west Greece and north Peloponnesus. Analysis of genotype composition in the samples was achieved by polyacrylamide electrophoresis of the PCR products, for every genetic marker and then autoradiography. The statistic analysis of our results using software programs, revealed an important genetic differentiation in samples. Except for many factors (climatic conditions, geographic origin), the host origin will be responsible for this genetic differentiation.
103

Heavy metals in South African medicinal plants.

Street, Renée Anne. January 2008 (has links)
Plants are able to take up and accumulate certain environmental contaminants such as heavy metals. When the plants are ingested by man, these contaminants are transferred along the food chain. Due to the poorly regulated medicinal plant trade in South Africa, many opportunities exist for heavy metal contamination of medicinal plants namely contaminated harvest sites as well as poor drying, processing, storage, transport and manufacturing conditions. The concentrations of five heavy metals (As, Cd, Co, Ni, Pb) and six microelements (B, Cu, Fe, Mn, Mo, Zn) were determined in some commonly used South African medicinal plants obtained from street markets. Elemental content was determined using inductively coupled plasma optical emission spectrophotometry (ICP-OES). Some of the medicinal plant samples investigated contained As and Cd at levels exceeding the World Health Organization limits of 1 and 0.3 mg kg-1 respectively. Lead and Ni were detected in all the samples. Elevated Fe and Mn levels were recorded in certain plant species. The results revealed multiple metal contamination in some medicinal plant parts sold in local markets and is thus grounds for concern. The effects of Cd application on growth parameters of some medicinal plant species belonging to the Hyacinthaceae (Albuca setosa, Eucomis autumnalis, Eucomis humilis, Merwilla plumbea) gave insight into heavy metal accumulation and distribution in these species. Application of Cd at 5 mg l-1 over a 12 week period reduced growth in A. setosa. The medicinally used A. setosa bulbs accumulated 37 mg kg-1 Cd after 12 weeks. Cadmium application at 2 mg l-1 over a six week period had no effect on growth parameters of E. autumnalis or E. humilis. However, a substantial difference in total Cd accumulation was detected in the plants (40.2 and 15.3 mg kg-1 respectively). Cadmium application at 2 mg l-1 significantly reduced the fresh weight of leaves, bulbs and roots of M. plumbea. Although most of the Cd was stored in the roots, the medicinally used bulbs accumulated up to 11.6 mg kg-1 when applied at 10 mg l-1. The antagonistic effect between Cd and Zn treatments and their effect on micronutrient distribution in M. plumbea were investigated. Five treatments were evaluated: (1) Hoagland’s nutrient solution (HS) (control) (2) HS + Cd 2 mg l-1 (single) (3) HS + Cd 2 mg l-1 + Zn 50 mg l-1 (combination) (4) HS + Cd 2 mg l-1 + Zn 100 mg l-1 (combination) (5) HS + Cd 2 mg l-1 + Zn 150 mg l-1 (combination). Cadmium readily accumulated in leaves, bulbs and roots of M. plumbea when supplied at 2 mg l-1. Zinc at 50 mg l-1 led to increased Cd accumulation. However, further increases in Zn concentration showed an antagonistic effect of Zn on Cd uptake and accumulation. Thus, increasing Zn levels in soils may be favourable for reducing toxic Cd accumulation in M. plumbea plants. Boron was not significantly affected by the addition of Cd to the media. However, with an increase in Zn, leaf B content increased while the B content in the bulbs and roots decreased. Copper and Mo levels were not significantly affected by treatments with Cd or Cd/Zn combinations. Compared to the control, Cd and Cd/Zn applications caused an increase in Mn content in leaves, bulbs and roots. Iron levels of M. plumbea were not significantly affected by Cd in the media. However, with an increase of Zn in the Cd-containing media, Fe content in the leaves, bulbs and roots increased. Tulbaghia violacea is one of the few medicinal plants that is also frequently used as a leafy vegetable. Application of Cd at 2 and 5 mg l-1 to T. violacea of varying sizes (small 8 - 10 g, medium 16 - 20 g, large 80 – 95 g) elicited a difference in growth response, Cd accumulation and micronutrient distribution. Leaf length and fresh weight of leaves of the medium-size plants decreased with application of Cd at 2 mg l-1 whilst 5 mg l-1 Cd significantly decreased the number of leaves in small-sized plants. Small plants accumulated more Cd in the leaves than medium- or large-sized plants. Application of Cd at 2 mg l-1 and 5 mg l-1 lowered the leaf Cu, Fe, Mo and Zn contents in small- and medium-size plants. This study indicated that T. violacea has the ability to accumulate Cd. In addition, plant size plays an important role with regards to Cd accumulation and elemental distribution. The effect of various nutrient applications (10%, 50% and 100% Hoagland’s nutrient solutions (HS); and HS deficient in N, P or K) on growth parameters and micronutrient distribution in Dioscorea dregeana were investigated. Irrigating plants with 50% HS resulted in better growth performance, whereas a deficiency of either N, P or K negatively affected seedling growth. Plants grown in 10% HS contained higher total B, Fe and Mo levels compared to seedlings grown in 50% and 100% HS. Compared to the control, P deficiency resulted in a Fe increase in the leaves, tuber and roots while a lack of P and K significantly increased total Mn content in D. dregeana. The effect of excess Zn (100, 200 and 300 mg l-1) on growth performance, chlorophyll content and microelemental distribution on Dioscorea sylvatica was investigated. Growth parameters showed a significant decrease when supplied with Zn at 100 mg l-1. Zinc phytotoxicity was evident by the reduction in chlorophyll content. Highest Zn concentrations were detected in the roots. Certain micronutrients appear to be redistributed due to Zn toxicity. The effect of microelements (Cu, Zn) and heavy metals (Cd, Pb, Hg) on germination and seedling development of Bowiea volubilis, Eucomis autumnalis and Merwilla plumbea was investigated. Copper and Zn applied at 1 mg l.1 significantly reduced the percentage germination of E. autumnalis. Low concentrations (. 1 mg l.1) of Cu and Zn negatively affected the root growth of all three species. Mercury concentrations of 0.5 and 1 mg l.1 significantly decreased the percentage germination of B. volubilis and E. autumnalis respectively. Cadmium and Hg at 2 mg l.1 showed a negative effect on the root growth of B. volubilis. Concentrations of 0.5 mg l.1 of all heavy metals tested significantly decreased shoot length of M. plumbea. The effect of Cd on biological activity (anti-inflammatory, antibacterial and antifungal) of medicinal plants with previously confirmed activity was evaluated. When supplied with Cd at 2 mg l-1, Eucomis humilis bulbous extracts showed lower anti-inflammatory activity than the control for both COX-1 and COX-2 activity. Eucomis autumnalis bulbous extracts had greater COX-1 activity compared to the control. However, Cd suppressed the activity of COX-2. Compared with non-Cd-treated Merwilla plumbea plants (control), those supplied with Cd at 10 mg l-1 showed increased antibacterial activity against Bacillus subtilis, Klebsiella pneumoniae and Staphylococcus aureus. However, no change in activity against Escherichia coli was observed. Cadmium accumulation in the bulbs had no effect on antifungal activity of Tulbaghia violacea. Thus, optimized agricultural practices are essential for quality control of cultivated medicinal plants. The studies presented in this thesis collectively answer several questions related to heavy metal involvement in South African medicinal plants. The findings substantiate the need to regulate and monitor the South African medicinal plant trade against heavy metal contamination which will in turn provide a product of safety and quality to the consumer. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.
104

Diversity of rice weeds vegetation and its potential as local forage resource in Java, Indonesia

Kumalasari, Nur 11 June 2014 (has links)
No description available.
105

Caracterização biofísica e radiométrica de pastagens cultivadas no Cerrado Goiano / Radiometric and biophysical characterization of pastures cultivated in the Cerrado Goiano

SANTOS, Gitair Moreira dos 17 December 2010 (has links)
Made available in DSpace on 2014-07-29T15:32:01Z (GMT). No. of bitstreams: 1 Gitair Moreira.pdf: 3199339 bytes, checksum: 54ae8591c642548d5c83145316112eef (MD5) Previous issue date: 2010-12-17 / The goal of this research was a thorough assessment of the biophysical and radiometric characteristics of the cultivated pastures in the Cerrado biome, based on both field and remote sensing data acquired in August 2009 and February 2010. The study area, located in the State of Goiás, Central Brazil, comprises an area of approximately 77.806 km², between latitudes 14º 00 S and 16º 30 S, and longitudes 48º 30 and 51º 10 W. Based on our data and results, we found a substantial difference between the two periods investigated, particularly concerning the green biomass and % green cover. While the total biomass remains mostly unchanged, the green biomass varies from 1.2 to 3.1 t/ha between August and February. Likewise, the % green cover increases as much as 65%. All these data and results, situated within the context of a larger initiative, certainly may be instrumental in promoting a more effective and sustainable pasture management in the Cerrado biome. / A presente pesquisa teve como objetivo identificar as características biofísicas e radiométricas das pastagens cultivadas do bioma Cerrado através de dados de campo e sensoriamento remoto, obtidos em agosto (período seco) e fevereiro (período chuvoso). A área de estudo localiza-se na região Centro-Oeste do Brasil, com 77.806 km², coordenadas geográficas latitude 14º 00 S a 16º 30 S e longitude 48º 30 e 51º 10 W. Com base em nossos dados e resultados há uma diferença significativa entre os dois períodos analisados, no que diz respeito aos valores de biomassa verde e porcentagem de verde, com exceção dos valores de biomassa total. Enquanto para a biomassa total os valores são 7,3 e 7,4 toneladas por hectare, em agosto e fevereiro, respectivamente, a biomassa verde varia de 1,2 para 3,1 toneladas por hectare entre agosto e fevereiro. No caso dos valores de % de verde, esta variação é ainda muito mais significativa, variando de 6 a 65%, respectivamente. A expectativa é de que estes dados, gerados e analisados no âmbito de um projeto maior de pesquisa, que envolve vários componentes temáticos e uma equipe multidisciplinar, permitam uma ocupação mais efetiva e ambientalmente sustentável das pastagens no bioma Cerrado.
106

Réinventer les pommes et les pommes de terre : une géographie de la qualité à l’épreuve des produits ordinaires / Reinventing apples and potatoes : applicability of the geography of quality to ordinary products

Garcon, Lucile 11 September 2015 (has links)
Dans un contexte de foisonnement des circuits courts de proximité, les enjeux de qualité invitent à déplacer la focale géographique, de produits spécifiques caractérisés par leur origine vers des produits ordinaires caractérisés par leur provenance. Se pose alors la question des modalités d’attachement de ces produits ordinaires aux milieux géographiques. À la fois aliments du quotidien et éléments de matériel végétal communs, les pommes et les pommes de terre permettent d’aborder les enjeux de reconnexion entre agriculture et alimentation autour de la notion de système agri-alimentaire territorial. Sur trois espaces de moyenne montagne – en France (Ardèche, Bauges) et en Italie (Ligurie) – cette thèse propose une analyse des trajectoires de dix collectifs passant par des phases de controverses qui les conduisent à se tourner vers des dispositifs de qualification plus souples que les indications géographiques. Conservant des logiques d’enracinement inspirées d’une rhétorique du terroir, ils ne versent pas pour autant dans le modèle des circuits courts de proximité, et maintiennent pour la plupart la question variétale au cœur de leurs préoccupations. La thèse montre que cette dernière ne peut être traitée à l’échelle des territoires qu’à condition d’envisager la production alimentaire de manière intégrée, c’est-à-dire en impliquant une diversité d’acteurs, capables de concevoir dans un même mouvement différentes étapes de qualification, de la gestion du matériel végétal à la consommation des aliments. L’émergence et la viabilisation de tels systèmes agri-alimentaires territoriaux ouvrent des débats politiques, et posent la question des modalités de l’action publique pour favoriser de tels dispositifs, dont on observe qu’ils tiennent principalement à des figures individuelles et à des lieux de médiation. / In a context of proliferation of short supply chains, issues of quality invite a shift in geographical focus, moving from specific products characterized by their origin to ordinary products characterized by their provenance. This shift raises the question of the modalities of attachment that these common products have to geographical areas. Everyday foods and common plant materials such as apples and potatoes allow for particular discussion around the issues concerning the reconnection of agriculture and food, specifically around the concept of territorial agri-food systems. Looking at three medium mountain areas - in France (Ardèche, Bauges) and Italy (Liguria) - this thesis proposes an analysis of the trajectories of ten different food collectives through the varying phases of controversy that are driving them towards qualification devices which are more flexible than purely geographical indications. Maintaining the logic of 'rooting', inspired by a territorial rhetoric, the collectives do not fall into the short supply chains model, and maintain, for the most part, the varietal question at the heart of their concerns. This thesis shows that this varietal question can only be treated at the territorial level if we consider the production of food as integrated. That is to say, involving a variety of stakeholders, capable of designing various stages of qualification in the same movement, from plant material management to food consumption. The emergence and realizable qualities of these territorial agri-food systems incite political debate, and raise the question of the public action modalities to promote these devices, which we notice are mainly due to individuals and places of mediation.
107

Svenska baljväxter från förr : en sensorisk beskrivning / Swedish legumes from the past : a sensory description

Dahl Petersson, Charlotta, Rojas Carvajal, Carlos, Uhlmann, Jenny January 2013 (has links)
Inledning: Baljväxter har flera miljö- och näringsmässiga fördelar och spås att bli framtidens föda. I Sverige finns det en värdefull kulturskatt som består av svenska baljväxter från förr som har samlats in av Programmet för odlad mångfald, POM. För att nå ut till konsumenter kan en sensorisk beskrivning vara en framkomlig väg som samtidigt ger ett mervärde för produkten och befrämjar en ökad konsumtion av baljväxter. Syfte: Syftet med detta examensarbete, inom ämnet mat och måltidskunskap, är att ta fram sensoriskt beskrivande ord för sex svenska baljväxter från förr. Examensarbetet ska sedan beskriva de utvalda svenska baljväxterna med hjälp av de framtagna sensoriskt beskrivande orden för att kunna presentera eventuella sensoriska skillnader. Material och metod: Sex olika sorters baljväxter ingick i undersökningen som bestod av en kvalitativ gruppdiskussion där sensoriskt beskrivande ord togs fram och ett andra steg en kvantitativ intensitetsbedömning av de olika sorterna. Båda undersökningarna gjordes av en expertpanel utvalda för sin kunskap om baljväxter. Resultat: De sensoriska ord som beskriver baljväxter är sötma, syrliga, beska, kastanj, nötig, smörig, frisk och fyllig smak samt med en varierande eftersmak. Munkänslan beskrivs med orden mjölig, krispig, fast och len. Intensitetsbedömningarna visade på små smakskillnader mellan baljväxterna men trots detta fanns särskiljande attribut för de sex olika baljväxtsorterna. Slutsats: De beskrivande sensoriska ord som detta examensarbete har utmynnat i kommer att hjälpa konsumenten att hitta rätt och öka mervärdet på produkterna. Samtidigt bevaras den svenska kulturskatten och konsumenten kan utveckla sin kulturella identitet tillsammans med alla de fördelaktiga egenskaper baljväxter besitter. / Introduction: Legumes have many favourable health and environmental benefits and are predicted to be the diet of the future. Sweden sits on a cultural treasure when it comes to legumes from the past that have been collected by The programme of cultivated diversity, POM. A sensory description would be a valuable tool to reach the consumer and a way to increase the consumption and value of the product. Purpose: The purpose of this thesis is to identify and bring forward sensory descriptive words for six Swedish legumes from the past. This thesis will also describe the Swedish legumes using the sensory descriptive words to evaluate whether there are sensory differences. Method: Six different types of legumes were used in the two surveys. The first survey consisted of a qualitative group discussion and the goal was to bring forward sensory descriptive words for the legumes. The second survey consisted of a quantitative intensity evaluation of the legumes. Both surveys were made by a panel of experts, chosen for their knowledge of legumes. Result: The sensory words which best describes the legumes are sweet, sour/acidic, bitter, chestnut, nutty, buttery, fresh, rich taste and with variations in aftertaste. The mouthfeel can be described as mealy, crisp, solid and tender. The evaluation of intensity proved the legumes to have few taste varieties, but despite the sensory descriptions each of the six legumes were possible to distinguish. Conclusion: The sensory descriptive words that this thesis have lead to can help the consumer to chose the right product, increase the value of the product an at the same time preserve a cultural treasure of Sweden. It is also possible for the consumer to create a cultural identity with all the good benefits that the legumes possess.
108

Modélisation hydrologique distribuée des écoulements surface-souterrain à l’échelle d’un bassin versant bananier en milieu tropical volcanique (Guadeloupe, France) / Distributed hydrological modelling of surface and ground water flows of a banana-cultivated catchment in a tropical volcanic region (Guadeloupe, FWI)

Pak, Lai Ting 05 July 2013 (has links)
Aux Antilles, la disponibilité limitée des ressources en contexte insulaire et l'activité agricole à aux niveaux d'intrants fragilisent les ressources en eau. Dans les zones bananières à forts niveaux d'intrants, des phénomènes de pollution des eaux sont particulièrement marqués, notamment du fait de l'usage d'un pesticide, la chlordécone. La connaissance du fonctionnement des systèmes hydrologiques à l'échelle du bassin versant représente un enjeu primordial pour pouvoir estimer l'exposition de l'écosystème aux pollutions et pour prévoir l'évolution des contaminations dans le temps. L'objectif de la thèse a été de développer une modélisation mécaniste représentant les processus hydrologiques de surface et souterrains à l'échelle d'un bassin versant sur substrat volcanique, sous climat tropical humide, situé en zone bananière en Guadeloupe. En premier a été développé un modèle parcellaire de bilan hydrique adapté au cas des cultures bananières. Il a pour originalité de prendre en compte l'importante redistribution de pluie opérée par le couvert bananier et d'en simuler les effets en matière d'intensité et d'hétérogénéité intra-parcellaire sur les termes du bilan hydrique. Les résultats d'analyse de sensibilité montrent que la redistribution de la pluie augmente le ruissellement de surface ainsi que la percolation, en cohérence avec les observations de terrain, mais impacte peu ou temporairement l'évapotranspiration et l'humidité du sol. Le calage du modèle sur des données expérimentales indiquent une performance améliorée de la simulation du ruissellement par rapport à un modèle ignorant le mécanisme de redistribution. En second, le bassin versant expérimental de Féfé (17.8 ha) a fait l'objet d'une approche de modélisation intégrant processus hydrologiques de surface et souterrains basée sur un chaînage itératif des modèles MHYDAS et MODFLOW. Confrontée à une année hydrologique de mesures de débits à l'exutoire et de piézométries, l'approche de chaînage de modèles de surface et souterrain apparaît pertinente. Une limite majeure est toutefois la non prise en compte de la zone non saturée dans le processus de recharge des aquifères. L'analyse des simulations et de leurs écarts avec les données observées conforte plusieurs hypothèses issues des analyses expérimentales : un ruissellement de surface fortement hortonien, une contribution majeure des écoulement souterrains au débit à l'exutoire. Elle indique toutefois également une indétermination des processus majeurs lors des périodes de fortes pluies. Différentes hypothèses sont proposées qu'il conviendra d'évaluer dans des travaux futurs. Ce travail constitue une première étape pour évaluer les chemins d'écoulement majeurs et les dynamiques des contaminations par les produits phytosanitaires dans un milieu volcanique tropical sous culture bananière. / In the French West Indies (FWI), limited resources supply on island and farming with extensive uses of pesticides have damaged water resources. In environments under intensive banana production, water pollution can be of particular concern, with regards to the use of chlordecone, an insecticide to control the banana weevil. Understanding the hydrological behaviour of a catchment is a challenge in assessing the exposure of the ecosystem to pollutions and in predicting the long-term contamination dynamics. This thesis aimed at developing a model to simulate de surface and underground hydrological processes at the catchment scale on volcanic deposits in a humid tropical area covered by banana plantations in Guadeloupe. First, we developed an original water budget model at the plot scale, adapted to the banana canopy. It takes into account the high rainfall redistribution by banana cover and simulates the effects of modified rainfall intensities and within-plot heterogeneities on the water balance components. The sensitivity analysis showed that rainfall redistribution promotes surface runoff and percolation, in accordance with the field observations, but influences little or only temporarily the average field evapotranspiration and soil moisture. The model calibration tested on experimental data indicated improved runoff production performances compared to a model without rainfall redistribution. Secondly, the Féfé experimental catchment (17.8 ha) was studied with a linked iterative modelling approach (of MHYDAS and MODFLOW) that includes surface and underground hydrological processes. Tested against a year of outlet discharge and water table depth measurements, the linked modelling approach seems appropriate. However, the main limit of this approach was that it does not consider the transfer through the unsaturated zone when simulating the aquifers' recharge. The analysis of the results and of the differences between measured and simulated variables supported the hypothesis, from experimental analyses, that: the surface runoff is mainly Hortonian, groundwater flow is the main contributor to runoff at the catchment outlet. However, there was still uncertainty concerning the main processes during wet periods. Various hypotheses were suggested and should be investigated in future studies. This work represents a first step towards the evaluation of the major flow paths and contamination dynamics of pesticides on volcanic deposits in a humid tropical area covered by banana plantations.
109

Bovine and Porcine Adipogenesis, Myogenesis, and Tissue Engineering Strategies to Improve Flavor and Pigmentation of Cell-Based Meat

Krieger, Jessica 02 December 2020 (has links)
No description available.
110

De cendres et de braises : la stratégie culturelle de la France au XXIe siècle / Of Ashes and Embers : The Cultural Strategy of France in the 21st Century

Fregonese, Pierre-William 22 March 2018 (has links)
La stratégie culturelle est une composante essentielle de la stratégie globale de puissance d'un Etat au XXIe siècle. La France, puissance culturelle historique dotée d'un réseau diplomatique fort, structurant son action culturelle extérieure, voit une concurrence émerger sur la scène internationale. Pour garder son statut, elle défend la diversité culturelle, démarche complémentaire de celle d'exception culturelle, en conservant les acteurs traditionnels de l'influence. Or, dans une époque du tout numérique et de l'immédiateté, et de l'essor des acteurs privés, les codes de l'influence sont renouvelés, remettant en question la pertinence d'une action culturelle extérieure principalement publique. / In the 21st century, cultural strategy is a crucial component of a State’s overall strategies of power. France, a historically prominent cultural power whose strong diplomatic network structures its foreign cultural action, is being challenged by an emerging international rivalry. In order to maintain its status, France advocates for cultural diversity, as a process complementary to “cultural exception,” by retaining the traditional agents of influence. But in the age of the digital and of immediacy, and with the rise of private agents, the codes of influence are being renewed, which questions the suitability of a foreign cultural action that has largely remained publicly funded.

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