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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.
201

L’archéologie du pulque dans les Basses-Terres mayas : Analyse de résidus et archéologie expérimentale sur l’alcool rituel de la période Classique à Ucanal, Guatemala

Bisson, Florence 02 1900 (has links)
Les traditions alimentaires constituent l’un des moyens fondamentaux par lesquels les groupes culturels s’expriment et interagissent les uns avec les autres. Le cacao est un breuvage particulièrement bien étudié pour son rôle dans la cosmologie et la vie sociale maya, mais il ne s’agit pas du seul breuvage ayant occupé un rôle central au courant de la période Classique. Dans les dernières années de recherche archéologique en Mésoamérique, des preuves iconographiques et épigraphiques ont montré que les Mayas consommaient également le pulque, préparé avec la sève d’agave. Les vases et les bols en céramique de type Fine Orange, répandus à travers la région maya mais n’ayant jamais fait l’objet d’analyses de résidus auparavant, auraient pu servir à accueillir ces boissons élémentaires aux pratiques culturelles. Ces derniers étaient importés sur de longues distances en dehors de leur zone de production, suggérant qu’ils occupaient un rôle particulièrement important. La présente étude vise à identifier la présence de pulque et de cacao en relation avec la céramique Fine Orange dans le sud des Basses-Terres mayas à l’aide d’analyses de résidus organiques. Le site à l’étude, Ucanal au Guatemala, est idéal pour examiner cette question, puisque les fouilles archéologiques sur celui-ci ont révélé que ses habitants avaient des relations politiques et économiques sur de longues distances et avaient accès à des céramiques Fine Orange importées. Des méthodes de l’archéologie expérimentale ont été employées afin de mettre en place un cadre de référence pour les traces chimiques du pulque. La chromatographie en phase gazeuse couplée à la spectrométrie de masse a été employée sur les échantillons céramiques pour l’identification des biomarqueurs présents, comme la théobromine et les hopanoïdes. Un tel projet avait pour but de mieux étudier la possibilité que les anciens peuples mayas des Basses-Terres utilisaient la céramique Fine Orange pour le service et la consommation de boissons rituelles. Les résultats pourraient aussi permettre d’explorer la possibilité que les interactions entre les peuples de différentes régions étaient médiées par le partage de traditions alimentaires, plus particulièrement les boissons. / Food traditions are one of the several fundamental ways through which cultural groups express themselves and interact with each other. Cacao is a beverage that is particularly well studied for its role in Mayan cosmology and social life, but it is not the only beverage that played a central role in Maya foodways during the Classic period. In recent years of research in Mesoamerica, iconographic and epigraphic evidence has shown that the Maya also consumed pulque, prepared with agave sap. Fine Orange ceramic drinking vases and bowls, widespread across the Mayan region, could have been used to serve these drinks. They were exported long distances outside of their region of production, indicating that they were of particular importance. The present research aims to identify the presence of pulque and cacao in relation to Fine Orange ceramics in the Southern Maya Lowlands using organic residue analyses. The site under study, Ucanal, Guatemala, is ideal to examine this question since archaeological excavations have revealed that its inhabitants had political and economic relationships over long distances and had access to imported Fine Orange ceramics. Experimental archeology methods were used to establish a referential framework for the chemical traces of pulque. Gas chromatography coupled with mass spectrometry analysis was performed on ceramic samples to identify the presence of possible biomarkers, such as theobromine and hopanoids. Such a project aimed to further investigate the possibility that ancient Mayan peoples of the Southern Lowlands used Fine Orange ceramics for the serving and consumption of ritual drinks. The results would help explore the possibility that interactions between peoples of different regions were mediated by shared food traditions, particularly ritual beverages.
202

Improviserade ickevåldskonflikter : -Fallen Ukraina och Burma

Hellerud, Kristofer January 2007 (has links)
<p>The purpose of the essay is to investigate whether the principles formulated by Peter Ackerman and Christopher Kruegler, concerning strategic non-violent conflicts, can serve a purpose when analyzing improvised non-violent conflicts. The principles are derived from factors that have been prominent in earlier successful improvised non-violent conflicts.</p><p>The essay is based on two research questions; if the factors included in the principles formulated by Ackerman and Kruegler, exist in the two cases that this study investigates, and if those principles offer a satisfactory explanation for the outcome of an improvised non-violent conflict.</p><p>To answer the questions the study uses a comparative method, where the improvised non-violent conflict of 2004 in Ukraine is compared to the improvised non-violent conflict of 1988 in Burma.</p><p>The answer to the first question shows that the factors contained in the principles previously mentioned, exists in both cases. The answer to the second question is more uncertain, as there seems to be doubts on whether the case of Ukraine really was completely improvised. Another reason for caution is that the factors contained in the principles, only consider actions made by non-violent actors, and not by opponents or third parties. Thus the risks of missing vital explanatory factors are substantial.</p>
203

Effect of Sm1 on End-use Quality of Durum Wheat (Triticum turgidum L. var durum)

2013 May 1900 (has links)
Genetic resistance to the orange wheat blossom midge (Sitodiplosis mosellana; OWBM) is an important breeding target to prevent yield and quality losses of durum wheat produced in western Canada. To date, only a single characterized midge resistance gene, Sm1, has been identified. Sm1 confers antibiosis resistance to the OWBM. It has been genetically localized to chromosome 2BS of hexaploid wheat (Triticum aestivum L.). Sm1 has been introgressed into locally adapted germplasm. Currently, no Sm1 carrying durum wheat lines are available for commercial production, and no studies have characterized the influence of Sm1 on yield and end-use quality of durum wheat. The main objectives of this study were: 1) To determine the effect of Sm1 on grain yield and end-use quality. 2) To genetically map the Sm1 introgression. For this work, 122 F5:9 recombinant inbred lines (RILs) derived from a cross between the midge susceptible durum wheat cultivar CDC Verona (Sm1 “-”) and resistant experimental line DT780 (Sm1 “+”). Agronomic and end-use quality traits of the mapping population were analyzed. The results from each environment were used for quantitative trait loci (QTL) analysis at Kernen (SK) in 2009 and 2010, and at Indian Head (SK) in 2009. On average, the presence of Sm1 was associated with higher grain yield and yellow pigment content, but lower kernel weight, reduced grain protein content, and weaker gluten properties. However, it was possible to identify RIL lines carrying Sm1 that expressed higher kernel weight, grain protein content, and stronger gluten. A genetic linkage map spanning 58 cM on chromosome 2B near Sm1 was constructed. QTL mapping suggested that the total length of the Sm1 introgression into durum wheat was approximately 11cM. Nearly all traits measured showed QTLs associated with Sm1. For grain protein content, a QTL proximal to Sm1 was identified, suggesting that Sm1 per se may not be contributing to the reduced grain protein observed in the Sm1 carriers of the RIL mapping population. The results presented here suggest that on average, Sm1 is associated with higher grain yield and some reduced end-use quality factors, but that it may be possible to combine Sm1 with high grain yield and end-use quality equivalent to current check cultivars.
204

Ethanol Production from Cellulosic Biomass by Encapsulated Saccharomyces cerevisiae

Talebnia, Farid January 2008 (has links)
Unstable oil markets with rising environmental concerns have revived widespread interest in production of fuel ethanol from renewable materials. Cellulosic materials are abundant and prominent feedstocks for cheap ethanol production. However, due to recalcitrant structure of these materials, pretreatment is a prerequisite. Depending on the biomass, pretreatment and hydrolysis conditions, a number of degradation products and/or toxic components may be released that show strong inhibitory effects on the fermenting microorganisms. This thesis deals with application of encapsulation technology to ferment the highly toxic hydrolyzates without further pretreatment. Free cells could not tolerate presence of 5 g/l furfural in defined medium, and inhibitors in wood and peel hydrolyzates in batch mode of operation and fermentation failed. Continuous cultivation of wood hydrolyzate was only successful at 0.1 h−1 and the majority of cells lost their viability after 5 retention times. Encapsulated cell system could successfully ferment the synthetic medium containing 5 g/l furfural during sequential batch cultivations with ethanol yield of 0.41-0.42 g/g. Cultivation of undetoxified hydrolyzates was also carried out, where glucose and mannose were converted within 10 h without significant lag phase. However, a gradual decrease in cell activity was observed in sequential batches. Continuous cultivation was more successful, and wood hydrolyzate was fermented to ethanol by encapsulated S. cerevisiae at dilution rates up to 0.5 h−1. More than 75% of the encapsulated cells were viable in the worst conditions. Ethanol was produced with yield 0.44 g/g and specific productivity 0.14–0.17 g/g•h at all dilution rates. Contrary to wood hydrolyzate, where there is no preference for permeation of sugars or inhibitors through the capsules’ membrane, encapsulation technology was applied to eliminate inhibition of limonene in fermentation of orange wastes to ethanol. The capsules’ membrane, of hydrophilic nature, is practically impermeable to hydrophobic compounds such as limonene while allowing penetration of nutrients and products. While presence of 0.1% v/v limonene in the medium results in strong inhibition or even failure of cultivation with free cells, using this technique allowed fermentation of a medium containing 1.5% v/v limonene. The impact of encapsulation on the anaerobic growth pattern, morphological and physiological changes of S. cerevisiae over long-term application was investigated. The growth rate, total RNA and protein content of the encapsulated cells decreased gradually over repeated batch cultivations, while stored carbohydrates content increased. Within 20 batch cultivations, total RNA and protein content of encapsulated cells decreased by 39% and 24%, whereas glycogen and trehalose content increased by factors of 4.5 and 4, respectively. / <p>Akademisk avhandling som för avläggande av teknologie doktorsexamen vid Chalmers tekniska högskola försvaras vid offentlig disputation den 18 april 2008.</p>
205

Religious education in Black schools : a situation analysis

29 October 2014 (has links)
M.Ed. (Curriculum Studies) / Various observations by the researcher aroused an interest to investigate the position of Religious Education on Black Senior Secondary level. This study may in part be seen as a model as to why this subject has been introduced in Black Secondary schools. This study is also designed to enquire as to why the subject is taken as an examination subject in some schools and not in others.
206

The relationship between job satisfaction and turnover intention at Orange Impact (PTY) Ltd

Geldenhuys, Pieter Johannes. January 2015 (has links)
M. Tech. Business Administration / The objective of this study is to identify the intrinsic and extrinsic factors that cause turnover intention. Finally the relationship will be tested between job satisfaction and turnover intention. A four section questionnaire will be used to identify the intrinsic and extrinsic factors that have an influence on job satisfaction. The questionnaire will also test the employees intent to leave the organization. Random selected employees from all levels in the organization participated in this study. In this study gender, marital status and employment duration had a significant impact on job satisfaction.
207

Efeito do consumo diário de suco de laranja sobre a microbiota intestinal, composição corporal e perfil lipídico e glicídico de mulheres /

Fidélix, Melaine Priscila. January 2018 (has links)
Orientador: Thais Borges Cesar / Banca: Paula Garcia Chiarello / Banca: Renata Maria Galvão de Campos Cintra / Banca: Anderson Marliere Navarro / Banca: Katia Sivieri / Resumo: Introdução: Aos compostos do suco de laranja 100% puro (SL) são atribuídos várias propriedades biológicas, como atividade antioxidante, anti-hipertensiva, redutora do colesterol e glicemia sanguíneos, e atualmente estudos in vitro têm mostrado que o suco de laranja pode ter ação seletiva sob a microbiota intestinal. Objetivo: Investigar o impacto do consumo diário de suco de laranja sobre a microbiota intestinal e no perfil glicídico e lipídico em mulheres. Métodos: Foram avaliadas 10 mulheres por período de 120 dias, distribuídos em três etapas: (1ª): dieta livre de citrus 30º dia (30 dias); (2ª) ingestão de 300 mL/dia de SL 90º dia (60 dias); (3ª) dieta livre de citrus 120º dia (30 dias). Avaliação dietética e antropometria foram realizadas quinzenalmente durante o período experimental. Foram colhidas amostras de sangue, urina e fezes, no início do estudo e a cada 30 dias, até o final do experimento. Foi realizado: analise dos parâmetros bioquímicos; identificação dos metabólitos urinários por UHPLC-UV-VIS; e análise da composição da microbiota por sequenciamento de gene RNAr 16S. Resultados: A avaliação da composição corporal e a excreção urinária não mostraram alterações durante as etapas experimentais. Os parâmetros bioquímicos mostraram diminuição da glicose (-6,25%), da insulina (-32,7%) e da resistência à insulina (-43,8%), além do colesterol total (-13,9%), LDL (-16%) e triglicerídeos (-30%) com a ingestão de SL (90º dia). Após a parada do consumo de SL (120º dia), o... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Introduction: 100% pure orange juice (OJ) compounds are assigned to various biological properties, such as antioxidant, antihypertensive, blood cholesterol lowering and glycemia activity. Currently, in vitro studies have shown that orange juice can present selective action of intestinal microbiota. Objective: To investigate the impact of daily consumption of orange juice on the intestinal microbiota and on the lipid and glucose profile in women. Methods: Ten women were evaluated for 120 days at three differen stages: (1st) citrus-free diet 30th day (30 days); (2nd) intake of 300 mL / day SL 90th day (60 days); (3rd) citrus-free diet 120th day (30 days). Dietary assessment and anthropometry were performed biweekly during the experimental stages. Samples of blood, urine and feces were taken at the beginning of the study, and every 30 days until the end of the experiment. It was carried out: analysis of the biochemical parameters; identification of urinary metabolites by UHPLC-UV-VIS; and analysis of the composition of the microbiota by 16S rRNA gene sequencing. Results: Changes during the experimental stages were not found in evaluation of body composition and urinary excretion. Biochemical parameters showed a decrease in glucose (-6.25%), insulin (-32.7%) and insulin resistance (-43.8%), total cholesterol (-13.9%), LDL (-16%) and triglycerides (-30%) with ingestion of OJ (90th day). After stopping OJ intake (120th day), the biochemical parameters returned to the initial values... (Complete abstract click electronic access below) / Doutor
208

Production of bio-plastic materials from apple pomace : A new application for the waste material / Produktion av bio-plast material från äpplerester

Gustafsson, Jesper, Landberg, Mikael January 2018 (has links)
Extensive quantities of apple pomace are generated annually but disposal of this waste is still much disputed. In EU alone, 500 000 tons are produced every year. Without further treatment, the acidic character of apples with their high sugar and low protein content makes the pomace unsuitable for landfilling and animal feedstock. However, further treatment is usually not economically feasible. This study addresses this issue by introducing a new approach for the apple pomace to produce sustainable materials.  The high content of sugars in apple pomace which can be reshaped and reformed at higher temperatures makes the waste material suitable for plastic production. Other components found in apple pomace are 5 % proteins and 1.5 % fats. Fibers are abundant, dietary fibers amounts for more than half (55 %) the original apple pomace weight. Phenols, sorbitol and acids can be found in minor mount, 2 % or less. The apple pomace itself is a mixture of mostly pulp and peel which corresponds to 9/10 of the total mass. Whereas seeds, seed core and stalk are the remaining 1/10. The possibilities of utilizing apple pomace to produce biofilms and 3D shapes have been investigated. The effects of introducing orange pomace, another waste material produced in extensive quantities, to apple pomace samples has also been studied.  Two methods were used to produce bioplastic materials; solution casting and compression molding. Glycerol was used as a plasticizer. Apple pomace, either washed or not washed, was oven-dried and milled into a fine powder. Using compression molding, plates or cups of the two powders with different amounts of glycerol were prepared. Mixtures of apple pomace and orange pomace, with or without glycerol, were prepared in the same way. The apple pomace was also used in a film casting method to produce plastic films. Applying laser cutting to the plates and plastic films, dog-bone specimens were created whose mechanical properties were analysed using a universal testing machine.  Highest values in terms of tensile strength and elongation at max was reached with bioplastics produced from solution casting where the values varied in the range 3.3 – 16 MPa and 11 – 55 % respectively. The compression molding approach resulted in tensile strength values in the range 0.94 – 5.9 MPa whereas the elongation at max was in the range 0.30 – 1.9 %. A possible application for this material could be disposable tableware which does not require high mechanical strength.  It was shown that it is possible to produce 3D structures and plastic films from apple pomace. Washed apple pomace with glycerol has similar properties as not washed apple pomace without the plasticizer. Adding orange pomace to apple pomace samples increases the tensile strength at the expense of the elongation at max. The pressing conditions and powder size greatly effects the mechanical properties, where a larger powder size lower the values for the mechanical properties. This new approach paves the way for a new utilization of apple pomace to replace some petroleum-based materials and at the same time solve the disposal problem of apple pomace.
209

Produção de silagem de capim braquiária em pomar de laranja. / Silage production of brachiaria grass in orange orchard.

Forli, Fernanda 26 September 2003 (has links)
O objetivo desta pesquisa foi verificar a possibilidade da exploração simultânea de pomar de citros com braquiária da entrelinha para produção de silagem. O delineamento experimental foi inteiramente casualizado com três tratamentos principais quanto ao manejo da braquiária (A: adubação do pomar na linha e manejo da braquiária da entrelinha através de roçadas; B: adubação do pomar na linha, sendo a entrelinha cortada para silagem; C: adubação do pomar na linha e na entrelinha, sendo a braquiária cortada para silagem), com sete repetições, totalizando 21 parcelas de três linhas de citros cada. A linha central foi utilizada para avaliação dos citros, e a entrelinha central para avaliar a braquiária. Foram realizados dois cortes de braquiária na época das águas para avaliação da produção de MS e de atributos químico-bromatológicos (QB). Após o corte, a braquiária foi armazenada de três formas: congelada "in natura"; em minissilos de PVC, sem adição de polpa cítrica, e em minissilos de PVC com adição de polpa cítrica (7, 14 e 21%), com quatro repetições. O material foi ensilado por 35 dias, sendo após aberto e congelado. Avaliou-se, nas amostras congeladas, as características QB: MS, PB, FDN, pH e PT. Fez-se a determinação dos teores de macro e micronutrientes nas folhas de citros e da braquiária, e amostragem do solo da linha e da entrelinha para avaliação da fertilidade. No pomar de citros avaliou-se a produção e as características físicas e tecnológicas dos frutos nas épocas de safra e colheita temporã. Observou-se que a produtividade e as características tecnológicas e físicas dos frutos não foram afetadas pelo manejo da braquiária. No estado nutricional dos citros, observou-se diferença nos teores de cálcio, sendo superiores no tratamento C. Os atributos químicos do solo na linha do pomar não apresentaram diferença entre os tratamentos. Na braquiária, os tratamentos não influenciaram o estado nutricional e os principais atributos químicos do solo. Quanto à produção de MS, nos tratamentos B e C, observou-se diferença entre os mesmos nas duas épocas de corte, com produção de MS 60% superior em C. Nas características QB, houve influência dos tratamentos B e C, da época de corte e da prática de ensilagem em relação a MS, PB, FDN, pH e PT, além de interações entre essas variáveis. Em função dos resultados obtidos quanto à produção e qualidade de citros e da braquiária para ensilagem, conclui-se a viabilidade da exploração desse sistema (pomar de citros e braquiária para ensilagem), desde que seja feita reposição dos nutrientes extraídos através de adubação diferenciada para as duas espécies vegetais. / The objective of this study was to verify the possibility of simultaneous exploration of citrus orchard with brachiaria of interrow for silage production aiming at dairy cow food complementation. The treatment were: A - fertilization of the orchard in the row and manipulation of brachiaria of the interrow by hoeing; B - fertilization of orchard in the row, and having the interrow cut for the silage; C - fertilization of orchard in the row and in the interrow, having the brachiaria cut for silage. The experimental design was randomized blocks with 7 replications, totalling twenty-one parcels with three lines of citrus each. The central line was used for the evaluation of citrus and the central interrow to evaluate the brachiaria. Two cuts of brachiaria were made in the rainy season for the evaluation of dry matter ha -1 and chemical-bromatological attributes production. After cutting, the brachiaria was stored in three different ways: frozen in natura; stored in mini silos of PVC with and without the addition of citric pulp; with four replications. The material was stored in silo for 35 days, and it was opened and frozen afterwards. The following chemical-bromatological characteristics were evaluated within these material dry matter, raw protein, fiber acid detergent, free acidity, and buffer capacity. Macro and micronutrients’ contents in the leaves were determinated, and samples of soil in the row and interrow were taken for the evaluation of soil fertility. In the citrus orchard, the production and the physical and technological characteristics of fruits in two periods (in season and out of season) were evaluated. The results showed that the productivity and the fruits’ technological and physical characteristics were not affected by the way the manipulation of brachiaria in the interrow was conducted. Within the plants’ nutritional state, a difference only for the contents of calcium, which were superior in treatment C, could be observed. The soil’s chemical attributes in the orchard’s line did not present any difference among the treatments. Concerning the brachiaria, the treatments did not have any influence in the nutritional state, nor in the main soil’s chemical attributes. Concerning the production of dry matter, in treatments B and C, a difference between them was observed, in the two seasons of cut, in the production of dry matter: up to 60% for treatment C. Concerning the chemical-bromatological characteristics, there was an influence of the treatments B and C, of the cutting period and of the practice of storage in silos in relation to the contents of dry matter, raw protein, fiber acid detergent, free acidity and buffer capacity in relation; besides the interaction effects among these three variables. Due to the obtained results in relation to the production and quality of citrus and of brachiaria for storage in silos, we can conclude the viability of the exploration of this system (orchard of citrus and brachiaria for storage in silos), as long as the reposition of the extracted nutrients through different fertilization for each vegetal species is executed.
210

Impacto dos elementos terras raras no agroecossistema citrícola / Impact of rare earth elements in citrus agroecosystem

Turra, Christian 23 February 2010 (has links)
A cultura de citros exige aplicações constantes de fertilizantes para atingir níveis satisfatórios de produtividade. Fertilizantes contêm outros elementos químicos além daqueles de interesse, como, por exemplo, os elementos terras raras (ETR). Estudos mostram que aplicações de ETR podem aumentar o crescimento e a produtividade das plantas como também causar efeitos nocivos ao ambiente e ao homem. No Brasil, não é prática comum a adição de ETR em fertilizantes, porém alguns insumos contêm em sua composição. Os objetivos deste trabalho foram quantificar os ETR nos compartimentos planta, solo e insumos de agroecossistemas citrícolas, avaliar o modelo de distribuição, identificar as principais fontes de ETR e estudar os efeitos desses elementos na planta cítrica. Para determinação dos ETR, utilizou-se da análise por ativação neutrônica instrumental (INAA) e espectrometria de massas com plasma indutivamente acoplado (ICP-MS). Foram feitos experimentos no campo e em casa-de-vegetação. O experimento de campo foi realizado em quatro propriedades de citros, sendo duas sob sistema de produção orgânico e duas sob o sistema de produção convencional, na região de Borborema, SP, com a variedade Valência (Citrus sinensis L. Osbeck) enxertada sobre limão cravo (Citrus limonia Osbeck),. Amostraram-se 15 plantas em cada propriedade, sendo coletados folhas, frutos, solos e os principais insumos empregados. As concentrações de ETR nas folhas bem como o fator de transferência solo-planta foram semelhantes aos de plantas bioacumuladoras. As folhas assim como as partes do fruto apresentaram depleção de Ce. Na fruta cítrica, a concentração dos ETR apresentou a seguinte distribuição: casca > polpa > sementes = suco. As maiores concentrações de ETR nos insumos foram observadas para os fertilizantes fosfatados. O delineamento experimental utilizado nos dois experimentos em casa-de vegetação foi em blocos ao acaso. Nos experimentos em casa-de-vegetação com superfosfato simples e cloreto de lantânio realizou-se a semeadura de sementes de limão cravo em tubetes de polipropileno. Para o experimento com superfosfato simples, as plantas de limão cravo permaneceram nos tubetes por 6 meses e, a partir desse período, iniciou-se o transplante para sacos plásticos. Os tratamentos constituíram-se de diferentes doses de superfosfato simples (50 g, 100 g, 200 g, 400 g) aplicadas ao substrato. Após 2 meses, coletaram-se as plantas de limão cravo e analisaram-se as folhas e o caule. No experimento com cloreto de lantânio, a aplicação dos tratamentos (50 mg, 100 mg, 200 mg, 400 mg) deuse após 98 dias da semeadura. Três semanas após, coletaram-se as plantas. A planta de citros do estudo pode ser considerada uma bioacumuladora de ETR. Houve discriminação entre os sistemas de produção em 2005, 2006 e 2007 para Eu, Tb, Yb e Sc nos compartimentos solo e folha, com uma concentração significativamente (p<0,05) maior no sistema de produção orgânico. O limão cravo absorve ETR do fertilizante superfosfato simples. A planta de citros teve sua fisiologia alterada com a aplicação de lantânio, isto é, dependendo da dose pode haver um efeito benéfico ou prejudicial no crescimento, sugerindo seu potencial uso como fertilizante na citricultura / The citrus crop requires repeated application of fertilizer to achieve satisfactory levels of productivity. Fertilizers contain other chemical elements in addition to those of interest, such as the rare earth elements (REE). Some studies show that applications of REE may increase plant growth and productivity, but it can also be harmful to both the environment and man. In Brazil, adding REE to fertilizers is not a common practice, however it may be found in the composition of some inputs. The objectives of this study were to quantify the REE in plant, soil and inputs in citrus agroecosystems, to identify the inputs acting as REE sources to the citrus plant, to study the effects of REE in citrus and to evaluate the REE distribution model. The instrumental neutron activation analysis (INAA) and the mass spectrometry with inductively coupled plasma (ICP-MS) were performed to determine the REE. Field and greenhouse experiments were conducted. The field experiment was performed in four citrus properties, with Valencia variety (Citrus sinensis L. Osbeck) grafted onto \'Rangpur\' lime (Citrus limonia Osbeck), two under an organic production system and two under the conventional production system in the region of Borborema, SP. Fifteen plants were sampled in each property and leaves, fruits, soils and the main input used in these properties. REE concentrations in leaves as well as the REE soil-plant transfer factor were similar to those of bioaccumulator plants. Likewise the fruit parts, the leaves showed Ce depletion. The REE concentration in the citrus fruit was distributed as follows: skin > pulp > seeds = juice. The higher concentrations of REE in the inputs were determined for the phosphate fertilizers. The greenhouse experiments with simple superphosphate and lanthanum chloride included the sowing of \'Rangpur\' lime seeds in polypropylene tubes. Both greenhouse experiments had a randomized block design. For the simple superphosphate the \'Rangpur\' lime plants remained in the tubes for 6 months and then were transplanted into plastic bags. The treatments comprised different doses of simple superphosphate (50 g, 100 g, 200 g, 400 g) applied into the substrate. Two months later the \'Rangpur\' lime plants were collected and their leaves and stalk were analyzed. In the experiment with lanthanum chloride heptahydrate the application of the treatments (40 mg, 100 mg, 200 mg, 400 mg) occurred 98 days following sowing. Three weeks following the application of the lanthanum chloride the plants were collected. It can infer that this citrus plant can be considered a REE bioaccumulator. There was discrimination between the production system in 2005, 2006 and 2007 for Eu, Tb, Yb and Sc in the soil and leaves compartments, with a concentration significantly (p <0.05) higher in the organic production system. The \'Rangpur\' lime uptakes REE from the simple superphosphate fertilizer. The citrus plant physiology had changed with the application of lanthanum, ie depending on the dose may be a beneficial or harmful effect on growth, suggesting its potential use as fertilizer in citriculture

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