Dissertations / Theses on the topic 'Citroën'
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Prachař, Pavel. "Ocenění podniku Toyota Peugeot Citroën Automobile Czech, s.r.o." Master's thesis, Vysoká škola ekonomická v Praze, 2012. http://www.nusl.cz/ntk/nusl-163465.
Full textAlirand, Marc. "Etude par les bond graphs d'une suspension Citroën et conception d'une suspension à correction d'assiette active." Lyon 1, 1991. http://www.theses.fr/1991LYO10012.
Full textGay, Vincent. "Immigration, conflits sociaux et restructurations industrielles : les ouvriers immigrés de Citroën et Talbot au début des années 1980." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLE040.
Full textIn spring 1982, , immigrant workers led strikes in Aulnay-sous-Bois (Seine-Saint-Denis) and Poissy (Yvelines) car plants and joined the trade unions CGT and CFDT in massive numbers. In the following months, social conflicts were intense and varied in these plants but ended in 1984 after the strikes against collective redundancies failed. This cycle of social conflicts provides a suitable starting point for studying the ongoing changes relating to the immigrant workers' situation in the plants at the time. The immigrant workers faced the updating of production facilities and work organization and had to cope with new industrial choices and policies which questions the legitimacy of their being in France. Their integration in the French workers' movement enabled them to contest the subordinate positions in which they had been kept until then. However, the massive reduction in jobs and the prospect of the unskilled jobs' demise cast doubt on their future in the industrial world . Professional training and plans on returning to the country of origin highlight the options provided by the companies and the French State
GUIGUET, JULIANA MOREIRA SILVA. "L`INFLUENCE DES ASPECTS SOCIOCULTURELS ET ORGANISATIONNELS SUR LE PROCESSUS D`ADAPTATION DE L`EXPATRIÉ : LE CAS DE PSA PEUGEOT CITROËN." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2003. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=4118@1.
Full textCes dernières décennies, le phénomène de lenvoi de travailleurs à létranger, communément appelé expatriation, a fait lobjet détudes dans les domaines des sciences sociales, de la politique et de léconomie, de lanthropologie et de la psychologie. Dans le domaine administratif, la grande majorité des études se concentrent sur la gestion du processus de transfert et très peu sur ladaptation personnelle de lexpatrié. Lon constate également dans cette littérature que la plupart des études de cas font références à des entreprises nordaméricaines, au détriment danalyses prenant en compte une plus grande diversité culturelle. Dans ce contexte, cette étude apporte un nouvel éclairage sur le sujet, en analysant la situation dune entreprise dorigine européenne pratiquant lexpatriation dans sa gestion des ressources internationales. Lobjectif principal de létude a été didentifier comment et avec quelle intensité les aspects organisationnels et socioculturels influent sur ladaptation de lexpatrié. Lentreprise considérée est le constructeur automobile PSA PEUGEOT CITROËN qui possèdent des filiales dans différents pays. Ont été interrogés douze employés de lentreprise qui vécurent des échanges internationaux, que ce soit de la maison mère vers une filiale étrangère ou dune filiale vers la maison mère, certains dentre eux ayant vécus le cycle complet de lexpatriation jusquau retour dans leur pays dorigine. Parmi de nombreux aspects, il ressort que le contexte professionnel et la vie personnelle de chaque individu peuvent être des facteurs influençant son adaptation à la situation dexpatriation de façon plus significative que les différences culturelles entre pays.
Nas últimas décadas, o tema da transferência de profissionais entre países, à qual convencionou-se chamar de expatriação, tem sido foco central de estudo em diversos campos tais como as ciências sociais, políticas e econômicas, a antropologia e a psicologia. No âmbito da Administração, a maior parte dos estudos concentra-se sobre aspectos gerenciais do processo de transferência, com pouco foco sobre a adaptação pessoal do expatriado. Verifica-se também na literatura da área uma maior concentração de estudos de casos de empresas norteamericanas, em detrimento de análises que levem em conta diferentes realidades culturais. Assim, o presente estudo procura trazer nova luz ao tema, analisando uma situação que envolve uma empresa de origem européia que utiliza a expatriação como uma prática na gestão internacional de seus profissionais. O objetivo principal do estudo foi o de identificar quais, como e em que grau de intensidade os aspectos organizacionais e sócio-culturais influenciam a adaptação do expatriado. A empresa focalizada foi a PSA Peugeot Citröen, fabricante de automóveis de origem francesa que possui filiais em diferentes países. Foram entrevistados doze profissionais da empresa que experimentaram o processo de transferência entre países, tanto da matriz francesa para filiais quanto de filiais para a matriz, incluindo-se no grupo indivíduos que viveram o ciclo completo da expatriação, até o retorno ao seu país de origem. Entre outros aspectos, os resultados sugerem que as condições profissionais e de vida pessoal de cada indivíduo podem representar fatores que influenciam a sua adaptação à situação de expatriação de modo até mesmo mais significativo do que as diferenças culturais entre países.
Laštovičková, Eva. "Inbound logistics v automobilovém průmyslu a aktuální otázky týkající se služeb firmy GEFCO jako logistického integrátora pro klienta PSA Peugeot Citroën." Master's thesis, Vysoká škola ekonomická v Praze, 2007. http://www.nusl.cz/ntk/nusl-2300.
Full textIngallina, Patrizia. "Les politiques de réhabilitation et de reconquête des espaces intra-urbains : le "recupero" en Italie et la réhabilitation en France : deux conceptions diverses de la "réutilisation", les exemples de deux aires industrielles désaffectées : le "recupero" de l'aire Galileo à Florence, la réhabilitation/rénovation de l'aire Citroën à Paris." Paris 1, 1993. http://www.theses.fr/1993PA010556.
Full textCastro, Goncalves Luciana. "Les dynamiques d’apprentissage collectif développées au sein des directions de systèmes d’informatiob : l’équilibration entre projet et communauté de pratique : le cas de la direction des systèmes d’information du groupe PSA Peugeot Citroën." Châtenay-Malabry, Ecole centrale de Paris, 2005. http://www.theses.fr/2005ECAPA001.
Full textSnížek, Martin. "Strategie francouzských výrobců automobilů na mezinárodních trzích." Master's thesis, Vysoká škola ekonomická v Praze, 2012. http://www.nusl.cz/ntk/nusl-162266.
Full textLouis, Aurélie. "Etude multidimensionnelle des facteurs contextuels, cognitifs et de personnalité favorisant le développement de l'expertise dans les métiers du Groupe "PSA Peugeot Citroën" : une approche exploratoire." Paris 5, 2011. http://www.theses.fr/2011PA05H107.
Full textThe aim of this study is an analyze of operators' cognitive skills and characters. They have been identified by their abilities ("expert trades" and "project managers") in the field of the car industry. Indeed, factors are implied in the development of these two types of jobs. In this way, two tests: the "F-JAS, Fleishman Job Analysis Survey, and the "MBTI", Myers-Briggs Type Indicator, were carried to 18 expert trades and 9 project managers. These subjects were also interviewed about their professional activity. On one hand, the conceptual semantics and the F-JAS analysis results underlined significant differences between these two groups, regarding some cognitive skills and context elements. On the other hand, the character field about the MBTI analyse, did not show any dimension linked with the expertise. Then, these results have been refined with data geometric analysis. Some model profiles have been established. Lastly, some recommendations have been proposed for the expert trades' career management. Several training activities were also given; they aim to support the expert trades' professional growth through the transmission of their own specific knowledge and know-how
Vinogradov, Boris. "L’industrie automobile française et la Russie de 1954 à 2014." Electronic Thesis or Diss., Sorbonne université, 2021. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2021SORUL115.pdf.
Full textThe French automobile industry has been present in Russia for more than a century. French manufacturers have maintained their presence on the Russian market despite the many upheavals that the country experienced in the 20th century. The thesis analyses the activities of French automobile companies in Russia in the years 1954 - 2014. It covers two very distinct periods: the Soviet and the post-Soviet and shows continuity in the strategy of French car manufacturers on the Russian market. The study presents Franco-Russian cooperation in the automobile field under the prism of economic, political and technological relations between the countries. This cooperation is the result of a bilateral will on the part of France and the Soviet Union to widen the scope of their cooperation and to engage in long-term industrial projects. It is thus possible to highlight the importance of the technology transfer carried out within the framework of Franco-Russian automobile projects. Finally, the analysis of the Russian automobile market enables us to measure the role of France in the development of the Soviet and then Russian automobile industry. The example of Renault's presence in the post-Soviet Russia is a good illustration of the Renault- Nissan Group's strategy towards emerging countries. The "Renault Russia" plant in Moscow becomes the Renault Group's 4th largest plant in terms of production volume in 2014
El, Khoury Zaki. "Système indirect en climatisation automobile." ENSMP, 2003. http://www.theses.fr/2003ENMP1209.
Full textSkopina, Maria. "Le problème du site et du contexte dans l'architecture contemporain : le parc de La Villette et le jardin en mouvement du parc André-Citroën à Paris." Thesis, Paris Est, 2013. http://www.theses.fr/2013PEST1186.
Full textThe point of departure of this thesis research is the environment worries which are currently faced by the architects. The shift in priorities to the environment may be followed in the modern architecture of Paris, in the city where there are the most innovative, the most typical tendencies of the current time. The task of the research is to follow this evolution and two parks recently appeared in Paris: Park de la Villette by Bernard Tschumi and the park of André Citroën created by Gilles Clément are taken as the object of this analysis. The choice of the object is explained as follows: these two objects are derived from the diametrically opposed architectural approaches and at the same time they are very revealing for the architecture of its decade. Being focused on the architecture, the research has also interdisciplinary element. This work puts the objects of the analysis in their French and international cultural context. The research sets up parallels between the modern architecture and phenomenon from literature (fragmentary method of writing), philosophy (theory of fragments) and modern art
Verzat, Caroline. "Les logiques d'apprentissage collectif en recherche industrielle. Modèle de compréhension et de pilotage par les situations-type : recherche-action à la direction de la recherche de PSA-Peugeot-Citroën." Paris 9, 2000. https://portail.bu.dauphine.fr/fileviewer/index.php?doc=2000PA090080.
Full textCiavaldini, Bertrand. "Des projets à l'avant-projet : l'incessante quête de réactivité : analyse du processus de rationalisation de la conception automobile liée à l'évolution du produit en termes de complexite et d'innovation au sein du groupe PSA Peugeot Citroën." Paris, ENMP, 1996. http://www.theses.fr/1996ENMP0593.
Full textCitrola, Penny. "Creating tools to educate and engage how interactive media can aid in scientific understanding /." Thesis, Montana State University, 2008. http://etd.lib.montana.edu/etd/2008/citrola/CitrolaP0808.pdf.
Full textEsposti, Marlon Dutra Degli. "Adubação e nutrição nitrogenada de porta-enxertos de citros produzidos em citrovasos." Universidade Federal de Viçosa, 1999. http://www.locus.ufv.br/handle/123456789/11934.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico
Este trabalho teve como objetivo avaliar o crescimento dos porta- enxertos limoeiro “Cravo” (Citrus Iimonia Osbeck), limoeiro “Volkameriano' (Citrus volkameríana Ten. e Pesq.), tangerineira “Cleópatra” (Citrus reshni Hort. ex Tan.) e tangerineira 'Sunki' (Citrus sunki Hort. ex Tan.), cultivados em citrovasos com capacidade para 3 dm3 de substrato, em casa de vegetação. Foram adicionadas ao substrato as doses de N de O, 158, 316, 474 e 632 mg/dm3 para os Iimoeiros e de O, 193, 386. 579 e 772 mg/dm3 para as tangerineiras, sendo estas parceladas em 20 aplicações de uréia para os Iimoeiros e 24 para as tangerineiras, durante o período experimental. Utilizou- se o esquema fatorial (4 x 5), num delineamento em blocos casualizados, com três repetições. A unidade experimental foi composta por quatro citrovasos com uma planta em cada. O crescimento dos porta-enxertos diferiu com a aplicação das doses de N no substrato de cultivo. A tangerineira ‘Sunki’ apresentou maior número de folhas, área foliar e peso da matéria seca de folhas e raiz. Os Iimoeiros exibiram, durante o período experimental, as maiores alturas e o maior diâmetro do caule, chegando primeiro ao ponto de enxertia, sendo, portanto, considerados mais vigorosos que as tangerineiras nesse sistema de cultivo. Os Iimoeiros apresentaram menores exigências de N que as tangerineiras, visto que as doses de N (mg/dm3 ) que proporcionaram o máximo incremento de altura foram de 453 mg/dm3 para o limoeiro 'Cravo', 431 para o 'Volkameriano', 624 para a tangerineira “Cleópatra' e 610 para a 'Sunki'. O máximo diâmetro foi alcançado com as doses de 455, 433, 543 e 546 mg/dm3, respectivamente para os limoeiros ‘Cravo', ‘Volkameriano’ e tangerineiras “Cleópatra” e ‘Sunki’. A adição de N na forma de uréia ao substrato de cultivo influenciou os teores foliares de todos os nutrientes estudados nos diferentes porta-enxertos de citros. ºbservaram-se nos limoeiros, acréscimos nos teores de N-orgãnico. N-NOg' e N-total, decréscimo de K e maiores teores de Mn e Fé. Os teores de P, Ca. Mg, 8, Cu e Zn apresentaram pouca variação nesses porta-enxertos. Nas tangerineiras verificaram-se acréscimos de N-orgãnico, N-NOg' e N-total e decréscimos de P, K, S, Fe e Zn. Os teores de Ca, Mg, Mn e Cu tiveram pouca variação. Os teores de clorofila, determinados pela metodologia-padrão e com o medidor portátil SPAD-502, foram influenciados pelas doses de N. De modo geral, os porta-enxertos apresentaram pouca variação quanto aos teores de clorofila determinados nas folhas. Esses valores se correlacionaram positivamente com as caracteristicas de crescimento e teores de nitrogênio nas folhas, indicando que o monitoramento de N pode ser realizado com a utilização de tais determinações.
The objective of this work was to evaluate the growth of lemon tree rootstocks cv. ‘Cravo' (Citrus Iimonia Osbeck) and ‘Volkameriano' (Citrus volkameriana Ten. e Pasq.), and mandarin tree cv. ‘Cleopatra' (Citrus reshni Hort. ex Tan.) and ‘Sunki'(Citrus sunki Hort. ex Tan.), growing in citrus vases, 3 dm3 capacity, in greenhouse. Nitrogen was added to the substrate of the lemon trees in doses equivalent to O, 158, 316, 474 and 632 mg/dm3, and O, 193, 386, 579 and 772 mg/dm3 to the mandarin trees. These doses were parcelled into 20 applications of urea for the lemon trees and 24 applications for the mandarin trees, during the experiment. The experiment consisted of a factorial arrangement (4x5), carried out in a randomized block design, with three replications. The experimental unit was comprised of four citrus vases, with one plant per vase. Growth of rootstocks differed with the nitrogen application to the substrate. Mandarin ‘Sunki' presented the largest number of leaves, leaf area and leaf and root dry matter weight. The lemon trees presented the largest stem height and diameter during the experiment, reaching the grafting stage first and being therefore considered more vigorous than the mandarins in that cultivation system. The lemon trees showed less demand for nitrogen than the mandarin trees, since the nitrogen doses (mg/dm3) that produced maximum height increase were 453 for lemon tree cv. ‘Cravo', 431 for ‘Volkameriano’, 624 for mandarin cv. ‘Cleopatra’ and 610 for ‘Sunki’. Maximum diameter was reached with the doses 455, 433, 543 and 546 for the lemon trees ‘Cravo’ and ‘Volkameriano’ and the mandarins ‘Cleopatra’ and ‘Sunki’, respectively. The addition of N in the urea form to the substrate affected the leaf concentration of all studied nutrients for the different citrus rootstocks. It was observed an increase in the concentration of organic nitrogen, NO3-N and total-N, a decrease of K and a larger absorption of Mn and Fe for lemon trees. For mandarins, it was observed an increase of organic- N, NO3'N and total-N and a decrease of P, K, 8, Fe and Zn. The concentrations of Ca, Mg, Mn and Cu present little variation in those rootstocks. The chlorophyll concentration, measured by the standard methodology and with the SPAD-SOZ portable apparatus, were affected by the nitrogen doses. In general, the rootstocks present little variation with respect to the chlorophyll concentration measured in the leaves. These values were positively correlated with the growth characteristics and nitrogen concentration in the leaves. indicating that the monitoring of N can be accomplished using such determinations.
Bassi, Irma Zuni. "Function and regulation of citron kinase during cytokinesis in animal cells." Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708139.
Full textSantos, Mônica Silva. "Resistência de genótipos de citros a lagarta-minadora-dos-citros Phyllocnistis citrella Stainton, 1856 (Lepidoptera: Gracillariidae)." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/11/11146/tde-23062009-151517/.
Full textThe objective this study was to evaluate the effect of different cultivars, hybrids and genera related to Citrus on behavior and biology of the citrus leafminer (CLM), Phyllocnistis citrella. The effect of the host plant on feeding (nutritional) and oviposition behavior, and/or the biology of CLM was assessed to find resistant or tolerant genotypes.The insects were maintained in laboratory in cages. Lemon (Citrus limonia L. Osbeck) Cravo seedlings were used as host plant. Initially, 23 genotypes of citrus were screened by exposing the seedlings of these plants to adults of this pest. The susceptible lemon (C. jambhiri) Rugoso was used as control. Based on the number of eggs and pupae obtained on each plant, five genotypes were selected as the most promising: tangerina Sunki (Citrus sunki Hort. ex. Tanaka), the hybrids C x R4 (C. sunki x Poncirus trifoliata), C x R315 (C. sunki x P. trifoliata), M x P222 (C. sinensis x Tangor Murcott) and P. trifoliata (Trifoliata Limeira). So, the oviposition preference, and the development and reproduction of the insect were evaluated on these six genotypes. In the free-choice oviposition preference test the hybrid C x R315 and Trifoliata Limeira were the least preferred by CLM. In the no-choice test, the effect of genotypes was less evident occurring less oviposition in Trifoliata Limeira than in lemon Rugoso. The different genotypes of citrus did not influence the duration and viability of egg, larval and pupal stages of P. citrella. It was therefore observed that genotypes influenced size and pupal weight, being the hybrid C x R4 the least adequate. Females from larvae reared on hibrids C x R4 and C x R315 oviposited the least numbers of eggs. In the tolerance test, it was concluded that leaf damage was the better parameter for discriminating the genotypes in relation to attack by P. citrella. The fresh and dry weight were not adequate parameters for tolerance study. The genotypes Trifoliata Limeira and its hybrid C x R4 were tolerants to CLM while tangerina Sunki and the lemon Rugoso were susceptible.
Lopes, Felipe de Araújo. "Adubação em doses variadas em citros." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/11/11148/tde-20102010-142822/.
Full textThe cultivation of citrus has great importance in the world and in Brazil is one of the most representative crops for exports. Precision agriculture (PA) is described as a set of tools that allow managing the production system based on georeferenced information related to the spatial variability of crops. The PA is used in large-scale on annual crops showing results concerning improved information management and the rationalization of inputs use. Considering the importance of citrus to the economy of the Sao Paulo state and wishing to improve production practices the aim of this work was to identify the spatial variability of the attributes and elements of soil, leaves and yield of commercial orange orchards and compare management traditionally used by the farm with the effects of variable rate fertilization. The work was conducted in two areas located in Botucatu-SP, 25.7 hectares each, differentiated by soil type, elevation and year of planting. The areas were monitored and interfered for two seasons since the year 2008. Two treatments were established: applications of a constant rate (CR) and spatially variable rate (VR). In the first year, soil samples were collected in three different patterns and densities at a depth of 0-0.2 m (2 samples ha-1) and 0.2-0.4 m (1 sample ha-1) in the fertilization strip and in the between trees rows at 0-0.2 m depth (1 sample ha-1). From the analysis of samples taken in the range of fertilization at a depth of 0-0.2 m recommendations were calculated for liming and sources of nitrogen, phosphorus and potassium for VR treating that were applied by a prototype machine capable of varying rates automatically based on the prescription map. In the 2009/2010 year, the georeferenced samples were collected from soil and leaves georeferenced separating the treatments. The samples were recorded in both seasons and provided data for yield mapping of the areas. The results of georeferenced soil samples showed spatial variability of attributes. The average values of P were classified as \"medium\", for the areas in both treatments. The average values of K ranged from \"high\" and \"medium\" for CR and VR, respectively, in clay soil area and \"medium\" for the treatments of area 2. Mean levels of V% were classified as \"medium\" in the area and a \"low\" in area 2, with no difference between treatments. The variable rate fertilization resulted in savings of 230 kg ha-1 nitrogen, 5 kg ha-1 of phosphorus and 257 kg ha-1 potassium on average in the two plots. The yields increased from 19.3 to 39.3 t ha-1 (CR) and 41.8 t ha-1 (VR) in area 1 and from 15.3 to 33.4 t ha-1 (CR) and 33.3 t ha-1 (VR) of area 2. Leaf N, P and K did not differ between treatments and their averages were identified as high in both areas supporting the potential use of this tool.
Eda, Masatoshi. "Rho-dependent Transfer of Citron-Kinase to the Cleavage Furrow of Dividing Cells." Kyoto University, 2001. http://hdl.handle.net/2433/150183.
Full textRaiol, Júnior Laudecir Lemos [UNESP]. "Translocação de Candidatus Liberibacter asiaticus em citros." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/150096.
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Huanglongbing (HLB), causada pela bactéria Candidatus Liberibacter asiaticus (Las) que coloniza o floema das plantas cítricas, é considerada a doença mais grave e destrutiva dos citros. Aspectos da patogenicidade de Las ainda não estão compreendidos, dificultado pela condição não cultivável do patógeno. Entender como Las se movimenta internamente na planta para colonizar os diferentes tecidos é fundamental para o controle do HLB e a busca de materiais com potencial de resistência. O objetivo desse trabalho foi caracterizar a movimentação de Las em plantas de citros. Nos experimentos plantas de laranjeiras foram inoculadas por enxertia de segmentos de ramos de plantas infectadas de 2 - 3 cm de comprimento. Para estudo da velocidade de movimentação de Las nos vasos do floema, foi utilizado duas metodologias. A primeira envolveu poda sequencial do caule a diferentes distâncias do ponto de inoculação e avaliação de amostras de folhas seis meses após a inoculação. Já na segunda metodologia foi realizado a coleta de amostras de anéis de casca do caule a diferentes distâncias do ponto de inoculação e de raízes fibrosas. Foi avaliado também a influência de novos fluxos de crescimentos na movimentação de Las. Lotes de plantas foram podadas na parte aérea ou no sistema radicular para indução do crescimento. Plantas não podadas foram usadas como controle. Foram amostradas folhas que surgiram na planta após a inoculação, folhas velhas, anel de casca e raízes fibrosas a partir de 15 dias após a inoculação. E para o estudo do padrão de movimentação de Las nas plantas, foram utilizadas plantas aneladas totalmente, parcialmente e não aneladas no caule e inoculadas no topo ou na base do caule para avaliar se Las precisa passar pela raiz para colonizar outros pontos da copa. Os resultados permitiram concluir que a velocidade média necessária para Las atingir a raiz de 95% das plantas, localizada 85 cm abaixo do local de inoculação, foi estimado variando entre 2,9 a 6,9 cm dia-1. Foi observado também que fatores ambientais influenciam a velocidade de movimentação da bactéria na planta. No experimento para avaliar a influência das regiões de crescimento, parte aérea ou sistema radicular, na movimentação de Las, a maior probabilidade de detecção da bactéria foi observada em tecidos das regiões que foram estimulados a crescer através da poda, quando comparados com as plantas não podadas. Com relação aos tecidos amostrados, anéis de casca do caule foram as que apresentaram maiores porcentagens de detecção de Las. Além disso, as plantas em que foram estimulados o crescimento do sistema radicular apresentaram 90% a mais de probabilidade de se encontrar Las nas raízes em relação a amostras de casca do caule ou folhas. Os resultados sugerem que a bactéria precisa passar pela raiz para atingir outros pontos da copa. No entanto, esse fator não foi totalmente esclarecido porque o anelamento das plantas provocou acúmulo de amido e alteração no fluxo da seiva, que pode ter influenciado na movimentação da bactéria.
Huanglongbing (HLB), caused by the bacteria Candidatus Liberibacter asiaticus (Las) which colonizes the phloem of citrus plants, is considered the most serious and destructive disease of citrus. Las pathogenicity aspects are not yet understood, hampered by non-cultured condition of the pathogen. Understanding how Las moves within the plant to colonize the different tissues is fundamental for HLB management and searching for materials with resistance potential. The objective of this research was to characterize the movement of Las in citrus plants. In the experiments orange plants were inoculated using grafting segments from infected plant branches 2-3 cm long. To study the speed of Las movement in phloem, two methodologies were used. The first involved sequential pruning of the stem at different distances from the inoculation site and evaluation of leaf samples six months after inoculation. In the second methodology was collected the ring samples of stem bark at different distances from the point of inoculation until the ground level and fibrous roots. It was also evaluated the influence of the growth flows in the Las movement. Lots of plants were pruned in the aerial part or in the root system to induction of growth. Unpruned plants were used as controls. The plants were evaluated by sampling young leaves, mature leaves, stem bark and roots every 15 days from inoculation. For the study of the movement pattern of Las in the plants, we used totally, partially and non-girdling plants and inoculated at the top or base of the stem to evaluate if Las must pass through the root to colonize other points of the canopy. The results allowed to conclude that the average speed required for Las to reach the 95% root of the plants, located 85 cm below the inoculation site, was estimated varying from 2.9 to 6.9 cm day-1. It was also observed that environmental factors influence the speed of the bacterium movement in the plant. In the experiment to evaluate the influence of the growth regions, aerial part or root system, in the movement of Las, the highest probability of detection of the bacteria were observed in tissues from the regions that were stimulated to grow through pruning, when compared with unpruned plants. Regarding the sampled tissues, stem bark rings were the ones with the highest percentages of Las detection. Furthermore, the growth of the root system increased the possibility of finding Las in roots samples by 90% than in other sampled tissues. The results suggest that the bacteria must pass through the root to reach other parts of the canopy. However, this factor was not fully understood because the plants girdling caused starch accumulation and change in the sap flow, which may have influenced the movement of the bacteria.
Raiol, Júnior Laudecir Lemos. "Translocação de Candidatus Liberibacter asiaticus em citros /." Jaboticabal, 2017. http://hdl.handle.net/11449/150096.
Full textResumo: Huanglongbing (HLB), causada pela bactéria Candidatus Liberibacter asiaticus (Las) que coloniza o floema das plantas cítricas, é considerada a doença mais grave e destrutiva dos citros. Aspectos da patogenicidade de Las ainda não estão compreendidos, dificultado pela condição não cultivável do patógeno. Entender como Las se movimenta internamente na planta para colonizar os diferentes tecidos é fundamental para o controle do HLB e a busca de materiais com potencial de resistência. O objetivo desse trabalho foi caracterizar a movimentação de Las em plantas de citros. Nos experimentos plantas de laranjeiras foram inoculadas por enxertia de segmentos de ramos de plantas infectadas de 2 - 3 cm de comprimento. Para estudo da velocidade de movimentação de Las nos vasos do floema, foi utilizado duas metodologias. A primeira envolveu poda sequencial do caule a diferentes distâncias do ponto de inoculação e avaliação de amostras de folhas seis meses após a inoculação. Já na segunda metodologia foi realizado a coleta de amostras de anéis de casca do caule a diferentes distâncias do ponto de inoculação e de raízes fibrosas. Foi avaliado também a influência de novos fluxos de crescimentos na movimentação de Las. Lotes de plantas foram podadas na parte aérea ou no sistema radicular para indução do crescimento. Plantas não podadas foram usadas como controle. Foram amostradas folhas que surgiram na planta após a inoculação, folhas velhas, anel de casca e raízes fibrosas a partir de 15 dias ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Huanglongbing (HLB), caused by the bacteria Candidatus Liberibacter asiaticus (Las) which colonizes the phloem of citrus plants, is considered the most serious and destructive disease of citrus. Las pathogenicity aspects are not yet understood, hampered by non-cultured condition of the pathogen. Understanding how Las moves within the plant to colonize the different tissues is fundamental for HLB management and searching for materials with resistance potential. The objective of this research was to characterize the movement of Las in citrus plants. In the experiments orange plants were inoculated using grafting segments from infected plant branches 2-3 cm long. To study the speed of Las movement in phloem, two methodologies were used. The first involved sequential pruning of the stem at different distances from the inoculation site and evaluation of leaf samples six months after inoculation. In the second methodology was collected the ring samples of stem bark at different distances from the point of inoculation until the ground level and fibrous roots. It was also evaluated the influence of the growth flows in the Las movement. Lots of plants were pruned in the aerial part or in the root system to induction of growth. Unpruned plants were used as controls. The plants were evaluated by sampling young leaves, mature leaves, stem bark and roots every 15 days from inoculation. For the study of the movement pattern of Las in the plants, we used totally, partially and non-girdling ... (Complete abstract click electronic access below)
Doutor
Maciel, Hardi Schmatz. "Viabilidade e frigoconservação de borbulhas de citros." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2006. http://hdl.handle.net/10183/5989.
Full textThis work aimed to study the maintenance of the viability of ‘Valência’ orange and ‘Montenegrina’ mandarin tree buds. They arose from a protected environment and orchard, under different disinfestation processes and different storage periods in cold chamber. The experiment also evaluated the behavior of the reserve substances present in rootstocks in different storage periods. Two experiments were carried out in cold chamber at a temperature about 5ºC. In experiment 1, two citrus cultivars from protected environment, three chemical treatments (check, 1x treated with Captan, and 2x treated with a 10g/L dose of Captan), and three storage periods (0, 90, and 180 days) were evaluated, with four replications. In experiment 2, two citrus cultivars from a citrus orchard, three chemical treatments (check, 1x treated with Captan and 2x treated with a 10g/L dose of Captan) and five storage periods (0, 45, 90, 135, and 180 days) were evaluated, with four replications. Montenegrina cultivar maintained bud viable for 90 days without fungicide treatment, and for at least 180 days if submitted to 1 fungicide treatment when stored. Valência cultivar from a protected environment maintained bud viable for at least 180 days and there was no need of fungicide treatment. The reserve substances of the rootstocks reduced throughout the storage period.
Venos, Kamil. "Hodnocení CSR aktivit u vybraných společností." Master's thesis, Vysoká škola ekonomická v Praze, 2015. http://www.nusl.cz/ntk/nusl-262144.
Full textPio, Rafael. "Propagação de híbridos somáticos de citros e reação à infecção por Phytophthora nicotianae e vírus da tristeza dos citros." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/11/11136/tde-05072005-145602/.
Full textSomatic hybridization is a new alternative in citric species breeding, yielding somatic hybrids which may integrally keep the genetic combination of both progenitors involved in the hybridization. Thus, the objective of this work was to study the propagation and growth of somatic hybrids parental combinations with potential to be used as rootstock and to verify possible resistance/tolerance to trunk and roots infection by Phytophthora nicotianae and citrus tristeza virus (CTV). This work applied the following somatic hybrids: 'Cravo' lemon + sour orange, 'Caipira' orange + 'Cravo' lemon, 'Caipira' orange + 'Cleopatra' tangerine, 'Caipira' orange + 'Volkamerian' lemon, 'Caipira' orange + 'Rough' lemon, 'Cleopatra' tangerine + 'Volkamerian' lemon, 'Cleopatra' tangerine + sour orange, 'Cravo' lemon + 'Sunki' tangerine, 'Ruby Blood' orange + 'Volkamerian' lemon, 'Rohde Red' orange + 'Volkamerian' lemon and 'Valência' orange + Fortunella obovata. In hybrids propagation, stem cuttings of approximately 15 cm length were excised from matrix plants of respective somatic hybrids and submmited to rooting in intermitent nebulization chamber for 100 days. Later, the stem cuttings root system and air part were analyzed. In sequence, they were transplanted to plastic bags, conduced in only one hast and kept in greenhouse during 210 days, when monthly evaluations were performed concerning the air part and, in the end, root system evaluations. For the Phytophthora nicotianae and CTV infection essays, plants derived from the respective somatic hybrids originated from stem cuttings were used, as well as control plants. For the resistance/tolerance to P. nicotianae analysis, the needle method for the trunk infection test was applied, being the lesions quantified after 25 days post-inoculation. For the roots and radicels flashening test, substrate was infected with pathogen structures and the air part of the plants was analyzed at every 15 days; roots were analyzed 60 days after the essay implementation. To evaluate the somatic hybrids tolerance to CTV, it was adopted the method of tissues union (grafting), where the air part of the plants was analyzed once a month in three evaluations. On the stem cuttings rooting, the hybrids of 'Caipira' orange + 'Cleopatra' tangerine, 'Caipira' orange + 'Volkamerian' lemon, 'Cravo' lemon + 'Sunki' tangerine and 'Rohde Red' orange + 'Volkamerian' lemon presented the best results, with the hybrids of 'Caipira' orange + 'Volkamerian' lemon and 'Rohde Red' orange + 'Volkamerian' lemon being the top concerning the stem cuttings development after transplanting. The somatic hybrids of 'Cleopatra' tangerine + sour orange, 'Cravo' lemon + 'Sunki' tangerine, 'Cleopatra' tangerine + 'Volkamerian' lemon, 'Ruby Blood' orange + 'Volkamerian' lemon, 'Rohde Red' orange + 'Volkamerian' lemon and 'Caipira' orange + 'Volkamerian' lemon showed good results related to reducing the trunk flashening, and the somatic hybrids of 'Cleopatra' tangerine + 'Volkamerian' lemon, 'Cleopatra' tangerine + sour orange, 'Caipira' orange + 'Volkamerian' lemon and 'Caipira' orange + 'Cravo' lemon presented tolerance to roots and radicels flashening caused by P. nicotianae. The hybrids of 'Cleopatra' tangerine + sour orange and 'Valência' orange + Fortunella obovata showed to be intolerant to citrus tristeza virus.
Silva, Anderson Gonçalves da [UNESP]. "Dinâmica populacional de mosca-negra-dos-citros (Aleurocanthus woglumi Ashby, 1915) em pomares de citros em sistema agroflorestal e monocultura." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/91350.
Full textConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Entre os insetos pragas que mais preocupam os citricultores no estado do Pará, a mosca-negra-dos-citros, Aleurocanthus woglumi destaca-se por acarretar danos diretos e indiretos ás plantas cítricas, além de constituir praga quarentenária presente ou A2 de alerta máximo, restringindo o comércio com outras regiões. Por ser uma praga exótica, recém introduzida, faltam conhecimentos básicos para a implementação de um manejo adequado na região amazônica. Desse modo, o objetivo do presente trabalho foi avaliar a dinâmica populacional de mosca-negra-dos-citros em pomares de citros em sistema de plantio agroflorestal e monocultura, utilizando a metodologia geoestatística. A área experimental está localizada no município de Capitão Poço onde foram realizadas 12 amostragens durante o período de setembro de 2008 a outubro de 2009, avaliando a presença ou ausência da praga nas laranjeiras em ambos os sistemas de produção. Os resultados obtidos mostraram que o sistema de plantio agroflorestal apresentou maior incidência de plantas com presença de mosca-negra-dos-citros comparado ao sistema de plantio de citros em monocultura, houve influência da temperatura na regulação da população da praga e precipitações elevadas reduziram o número de plantas com presença de A. woglumi. Observou-se que a distribuição espacial da mosca negra dá-se, predominantemente, em agrupamentos com dependência espacial descrita pelo modelo esférico, formando reboleiras de 8,5 a 34m (alcance do modelo) para ambos os sistemas de plantio adotados
Among the insect pests of most concern to citrus growers in the state of Pará (Brazil), the citrus blackfly, Aleurocanthus woglumi stands to cause direct or indirect damage to citrus plants, besides being a pest is present or A2 of this alert, restricting trade with other regions. Being an exotic pest, recently introduced, it lacks basic knowledge for the implementation of appropriate management in the Amazon region. Thus, the objective of this study was to evaluate the population dynamics of blackfly in a citrus orchards from an agroforestry and monoculture plantations, using geostatistical methodology. The experimental area is located in the municipality of Capitão Poço where 12 samples were taken during the period September 2008 to October 2009, evaluating the presence or absence of the pest in orange in both production systems. The results showed that the system of agroforestry plantation had a higher incidence of plants with the presence of citrus blackfly compared with monoculture planting citrus crop, there was influence of temperature on the regulation of pest population and heavy rain reduced the number of plants with presence of A. woglumi. It was observed that the spatial distribution of the blackfly takes place predominantly in clusters with spatial dependence described by the spherical model, forming foci of 8.5 to 34m (range model) for both planting systems adopted
Silva, Anderson Gonçalves da. "Dinâmica populacional de mosca-negra-dos-citros (Aleurocanthus woglumi Ashby, 1915) em pomares de citros em sistema agroflorestal e monocultura /." Jaboticabal : [s.n.], 2010. http://hdl.handle.net/11449/91350.
Full textAbstract: Among the insect pests of most concern to citrus growers in the state of Pará (Brazil), the citrus blackfly, Aleurocanthus woglumi stands to cause direct or indirect damage to citrus plants, besides being a pest is present or A2 of this alert, restricting trade with other regions. Being an exotic pest, recently introduced, it lacks basic knowledge for the implementation of appropriate management in the Amazon region. Thus, the objective of this study was to evaluate the population dynamics of blackfly in a citrus orchards from an agroforestry and monoculture plantations, using geostatistical methodology. The experimental area is located in the municipality of Capitão Poço where 12 samples were taken during the period September 2008 to October 2009, evaluating the presence or absence of the pest in orange in both production systems. The results showed that the system of agroforestry plantation had a higher incidence of plants with the presence of citrus blackfly compared with monoculture planting citrus crop, there was influence of temperature on the regulation of pest population and heavy rain reduced the number of plants with presence of A. woglumi. It was observed that the spatial distribution of the blackfly takes place predominantly in clusters with spatial dependence described by the spherical model, forming foci of 8.5 to 34m (range model) for both planting systems adopted
Orientador: Arlindo Leal Boiça Junior
Coorientador: Paulo Roberto Silva Farias
Banca: José Carlos Barbosa
Banca: José Roberto Scarpellini
Mestre
Matsumura, Emilyn Emy. "Estudo das populações de vírus presentes em plantas de citros cultivadas em uma região afetada pela morte súbita dos citros." Botucatu, 2016. http://hdl.handle.net/11449/146739.
Full textResumo: A morte súbita dos citros (MSC) causou a morte ou erradicação de aproximadamente quatro milhões de plantas de laranja doce na principal região citrícola do Brasil. Embora sua etiologia ainda não esteja completamente resolvida, seus sintomas e distribuição (especial e temporal) indicam uma provável doença viral. Trabalhos anteriores associaram a MSC ao vírus da tristeza dos citros (CTV) e ao CSDaV (Citrus sudden death-associated virus), no entanto, os resultados obtidos destes trabalhos não são conclusivos. Afim de estudar as populações de vírus presentes em plantas de citros afetadas pela MSC, este trabalho realizou uma análise comparativa, através do sequenciamento de alta performance do transcriptoma e dos pequenos RNAs de plantas sintomáticas e assintomáticas para MSC. Os dados revelaram uma infecção viral mista, incluindo o CTV como vírus mais predominante, seguido do CSDaV, um pararetrovírus endógeno de citros (CitPRV) e dois possíveis novos vírus, putativamente denominados de Citrus jingmen-like virus (CJLV) e Citrus virga-like virus (CVLV). As análises de correlação com a MSC indicaram uma provável associação de plantas sintomáticas com o CitPRV, enquanto que os dois novos vírus mostraram estar mais associados com plantas assintomáticas. A associação mais evidente foi observada entre plantas sintomáticas e um genótipo específico de CSDaV, o que nos conduziu a um estudo mais específico de variabilidade genética de 31 isolados de CSDaV, obtidos de plantas MSC-sintomática... (Resumo completo, clicar acesso eletrônico abaixo)
Doutor
Barbosa, Ana Paula [UNESP]. "Imagens hiperespectrais no monitoramento da nutrição em citros." Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/110954.
Full textMuitos estudos em sensoriamento remoto tem por objetivo identificar as diferenças varietais, predizer o rendimento, identificar deficiências nutricionais das culturas, estimativas de área de culturas e outras informações espectrais. O imageamento hiperespectral sub-orbital é uma ferramenta potencial para monitorar o estado nutricional das plantas cítricas, uma vez que esta tecnologia tem mostrado eficientemente a deficiência de nitrogênio em outras culturas. Portanto, isso contribui para reduzir custos, tempo e trabalho quando usado em grandes áreas. Os principais objetivos deste estudo foram: (i) determinar o comportamento espectral em pomares de citros em imagens hiperespectrais de alta resolução coletados com aeronaves; (ii) analisar a correlação entre características da planta e parâmetros radiométricos, especialmente do estado nutricional de nitrogênio de pomares de citros. O experimento foi conduzido em pomares localizados em Lake Alfred e Auburndale, Polk County, Flórida, EUA. A variedade estudada foi a Valência (Citrus sinensis). As imagens hiperespectrais consistem de 128 comprimentos de onda do visível e do infravermelho próximo (457,2 - 921,7 nm). Dados detalhados de verdade terrestre foram coletados no mesmo período em que as imagens, para avaliar a nutrição foliar de pomares de citros. As características espectrais das árvores individuais foram identificadas utilizando valores de reflectância espectral média com base em pixel, em vários comprimentos de onda da imagem. As imagens hiperespectrais e a verdade de campo foram avaliadas com estatística, SIG e ferramentas de modelagem, como os índices de vegetação (NDVI, NDVI705, RVI, VOG1, entre outros). Os métodos Regressão Linear Múltipla Backward e Análise de Componentes Principais (PCA) foram utilizados para desenvolver modelos de predição para nitrogênio nas folhas. A combinação dos métodos ...
Many studies in remote sensing aim to identify varietal differences, predict yield, identify crop nutrition deficiencies, crop area estimates, and other spectral information of crops. Airborne hyperspectral imagery is a potential tool to monitor the nutrient status of citrus trees, since this sensing technology has been shown to efficiently detect nitrogen deficiency in other crops. Therefore, it contributes to save cost, time and labor when used over large areas. The objective of this study was: (i) to determine the spectral behavior of a citrus orchard in high resolution hyperspectral imagery collected with aircraft; (ii) to analyze the correlation between plant parameters and radiometric parameters, especially of the nitrogen nutritional status of citrus orchards. The experiment was conducted in orchards located near Lake Alfred and Auburndale, Polk County, Florida, USA. The variety studied is Valencia (Citrus sinensis). Hyperspectral images consist of 128 visible and near-infrared wavelengths (457.2 – 921.7 nm). Detailed ground truth data were collected at the same time as the imagery for assessing foliar nutrition of citrus groves. The spectral features of the individual trees were identified using pixel-based average spectral reflectance values at several wavelengths from the image. Hyperspectral images and ground truth data were assessed with statistical, GIS and modeling tools, i.e. Vegetation Index (Normalized Difference Vegetation Index, Red Edge Normalized Difference Vegetation Index, Modified Red Edge Simple Ratio, Vogelmann Red Edge Index 1, and others.). The methods Backward Multiple Linear Regression and Principal Component Analysis (PCA) were used to develop prediction models for leaf nitrogen. These results will contribute to the development of rapid detection techniques of nutritional status in citrus groves, in order to reduce the sampling procedures for foliar analysis, which ...
Wetterich, Caio Bruno. "Imagem de fluorescência aplicada em doenças de citros." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/76/76131/tde-14102016-101443/.
Full textIn recent years, there has been an increasing interest in early detection of diseases that affect agricultural crops to avoid great economic losses due to contamination of new plants. The main citrus diseases, citrus canker and HLB, are a serious threat to citrus production worldwide, including regions in Brazil and the United States. The rapid spread of the diseases leads to the reduction of cultivated orchards resulting in economic losses to producers and industries. The development of methods for early diagnosis can result in an important tool for the control and management of citrus. Some nutritional deficiencies such as iron and zinc have similar visual symptoms to HLB, while the citrus canker can be confused with citrus scab and citrus leprosies, which may lead to incorrect diagnosis. Currently, only biochemical tests are able to detect, specifically, citrus canker and HLB, and thus distinguish them from other diseases and nutrient deficiencies. In this work, the fluorescence imaging spectroscopy technique with the learning and classification methods, SVM (Support Vector Machine) and ANN (Artificial Neural Network), were used to identify and discriminate the main diseases that affect citrus production in the states of São Paulo/Brazil and Florida/USA. The samples studied are citrus canker, citrus scab, HLB and zinc deficiency. The objective is to discriminate the diseases with similar visual symptoms, such as citrus canker from citrus scab and HLB from zinc deficiency for samples from Brazil and HLB from zinc deficiency for samples from the United States. The results show that it is possible to use the fluorescence imaging spectroscopy technique together with the classification methods for the discrimination of the diseases that have similar visual symptoms. Both classifiers showed high accuracy in the classification of the samples from Brazil and the United States, highlighting the efficiency of the technique under different conditions.
Marques, João Paulo Rodrigues. "Podridão floral dos citros: histopatologia de Colletotrichum acutatum." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/11/11144/tde-17092012-160523/.
Full textThe postbloom fruit drop (PFD) is a disease caused by Colletotrichum acutatum responsible for causing great damage to citrus crops in Brazil. The disease appears only in flower buds 8 mm in length or greater, leading to orange lesions in petals, necrotic lesions on the stigma, promoting the young fruit drop and the retention of the calyx and peduncle, which is called buttons. In this context, this study aimed to: observe the fungus penetration mode into the host Citrus sinensis \'Valência\' and the later stages of colonization; study the presence of preformed structural and chemical factors to explain why the fungus cannot infect floral buds with less than 8 mm in length; characterize anatomically the symptom \"buttons\" and injured stigmas; investigate the ultrastructural changes in tissues of inoculated petals; analyze whether there is the establishment of a quiescent infection in leaf tissues, analyze pollen grains after inoculation in vivo and in vitro with the fungus. Healthy buds, petals and stigmas with and without lesions, were processed and analyzed using conventional light and electron microscopy techniques. Leaves and pollen grains were also inoculated and analyzed with light microscopy. It was developed a new staining method for fungal-infected plant tissues. The resistance of flower buds smaller than 8mm may be associated with preformed structural and chemical barriers. These buttons display the apex with interspersed papillae, with crystals in mesophyll and substomatic chamber and oil cavities, which are located very close to each other on the abaxial surface. In 8mm and 12mm flower buds, the papilas in the apex become weakly interspaced, the crystals are not observed and there is the increase of the distance between the oil cavities. The papillose cells are osmophores. In the symptom \"button\", it is noted in the abscission of the ovary, an installation of wound meristem. There is also the lignification in the pith of receptacle and pedicel that can be associated with the retention of these structures in the plant. In infected petals, it was found that C. acutatum can penetrate intra and intercelullar or via stomata. The fungus may grow subcuticular and intramural and colonize all tissues of petal. The new staining technique developed has proved very useful for histopathological analysis. The fungus is closely associated with vascular tissues. The acervulli occur on both surfaces of petals. The cuticle in the later stages of the lesion is altered, i.e., there is loss of striated ornamentation and increased deposition of lipophilic material. The synthesis of lipophilic materials involves rough and smooth endoplasmic reticulum and plastids. Vesicles from dictyosomes and multivesicular bodies were observed throughout the cell wall and are associated with the deposit of lipophilic material in the cuticle. There is the formation of protective layer over the stigma damaged area. The fungus shows chemotropism and grows toward the pollen infecting it 24 hours after inoculation. It is suggested that C. acutatum can use pollen grains for dispersal. After 48 hours of inoculation, the leaves have germinated conidia with appressoria.
Bogas, Andréa Cristina. "Avaliação da interação entre Methylobacterium spp. e citros." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/11/11137/tde-22102010-095454/.
Full textThe bacterium-plant interaction is a complex process that involves several biotic and abiotic factors that may result in neutral, beneficial or harmful interactions. The Methylobacterium genus has been described as endophytic bacterium in different host plants. It could benefit the plants by growth promotion and control of phytopathogens. In citrus, this endophyte colonizes the same pathogen-niche, and therefore many species of this genus are interesting candidates to symbiotic control against X. fastidiosa. It is known that the process of Methylobacterium-bacteria interaction is coordinated by genes whose expression is regulated by the Quorum Sensing (QS), which uses N-acyl homoserine lactones (AHLs) as signaling molecules. Its importance is associated with the biofilm formation, found in many plants as a strategy for bacterial colonization. However, the mechanisms in Methylobacterium-plant interactions are still poorly understood. Thus, this work studied in different ways, the interaction between Methylobacterium spp. and citrus, evaluating the effects of these bacteria on the seedling growth and the variation of gene expression. In this context, it was found that the specificity of bacteria-plant interactions and the bacterial inoculation methods are important to generate beneficial results on seed germination and host plant development. Possibly, IAA production and nitrogen biological fixation were the major involved mechanisms in citrus growth promotion by Methylobacterium spp. These bacteria seem to be transmitted horizontally in citrus plant. Aiming to employ Methylobacterium spp. to control phytopathogens in citrus plant, M. extorquens AR1.6/2 was genetically modified to express an endoglucanase A (EglA) enzyme. Using scanning electron microscopy was observed that the modified bacteria colonized the surface and interior of the Catharanthus roseus, a model plant for experiments with endophytic bacteria and X. fastidiosa. Furthermore, when inoculated with X. fastidiosa, these bacteria shared the seedlings xylem, suggesting that during the colonization and establishment in the host, these bacteria could interact. Studying the action of a AHL on the expression of genes involved in the interaction between M. mesophilicum SR1.6/6- plant it was observed that the presence of this molecule was important in the activation of genes expression mxaF (related to the establishment and methylotrophic metabolism); pat (related to adaptive and competitive advantages during the plant colonization); acdS (involved in bacterial metabolism and modulation of hormone levels in the plant). Expression of crtI and sss, involved in bacterial stress and transport of compounds, respectively, and phoU, related with pathogenicity were not altered in the presence of AHL in the evaluated conditions. The results of this study demonstrated that Methylobacterium spp. interact with seedlings of Citrus spp., showing specificity between plant species and endophytic bacteria. Also, it was observed that this interaction occurs not only with the plant molecular modification levels, but possibly with other bacteria that inhabit the xylem of citrus. Also, this interaction Methylobacteriumcitrus- xylem bacteria may be regulated by AHLs.
Barbosa, Ana Paula 1983. "Imagens hiperespectrais no monitoramento da nutrição em citros /." Botucatu :, 2014. http://hdl.handle.net/11449/110954.
Full textCoorientador: Roberto Lyra Vilas Bôas
Banca: Paulo Milton Barbosa Landim
Banca: Edson Luís Piroli
Banca: Rodrigo José Pisani
Banca: Luis Gustavo Fredianni Lessa
Resumo: Muitos estudos em sensoriamento remoto tem por objetivo identificar as diferenças varietais, predizer o rendimento, identificar deficiências nutricionais das culturas, estimativas de área de culturas e outras informações espectrais. O imageamento hiperespectral sub-orbital é uma ferramenta potencial para monitorar o estado nutricional das plantas cítricas, uma vez que esta tecnologia tem mostrado eficientemente a deficiência de nitrogênio em outras culturas. Portanto, isso contribui para reduzir custos, tempo e trabalho quando usado em grandes áreas. Os principais objetivos deste estudo foram: (i) determinar o comportamento espectral em pomares de citros em imagens hiperespectrais de alta resolução coletados com aeronaves; (ii) analisar a correlação entre características da planta e parâmetros radiométricos, especialmente do estado nutricional de nitrogênio de pomares de citros. O experimento foi conduzido em pomares localizados em Lake Alfred e Auburndale, Polk County, Flórida, EUA. A variedade estudada foi a Valência (Citrus sinensis). As imagens hiperespectrais consistem de 128 comprimentos de onda do visível e do infravermelho próximo (457,2 - 921,7 nm). Dados detalhados de verdade terrestre foram coletados no mesmo período em que as imagens, para avaliar a nutrição foliar de pomares de citros. As características espectrais das árvores individuais foram identificadas utilizando valores de reflectância espectral média com base em pixel, em vários comprimentos de onda da imagem. As imagens hiperespectrais e a verdade de campo foram avaliadas com estatística, SIG e ferramentas de modelagem, como os índices de vegetação (NDVI, NDVI705, RVI, VOG1, entre outros). Os métodos Regressão Linear Múltipla Backward e Análise de Componentes Principais (PCA) foram utilizados para desenvolver modelos de predição para nitrogênio nas folhas. A combinação dos métodos ...
Abstract: Many studies in remote sensing aim to identify varietal differences, predict yield, identify crop nutrition deficiencies, crop area estimates, and other spectral information of crops. Airborne hyperspectral imagery is a potential tool to monitor the nutrient status of citrus trees, since this sensing technology has been shown to efficiently detect nitrogen deficiency in other crops. Therefore, it contributes to save cost, time and labor when used over large areas. The objective of this study was: (i) to determine the spectral behavior of a citrus orchard in high resolution hyperspectral imagery collected with aircraft; (ii) to analyze the correlation between plant parameters and radiometric parameters, especially of the nitrogen nutritional status of citrus orchards. The experiment was conducted in orchards located near Lake Alfred and Auburndale, Polk County, Florida, USA. The variety studied is Valencia (Citrus sinensis). Hyperspectral images consist of 128 visible and near-infrared wavelengths (457.2 - 921.7 nm). Detailed ground truth data were collected at the same time as the imagery for assessing foliar nutrition of citrus groves. The spectral features of the individual trees were identified using pixel-based average spectral reflectance values at several wavelengths from the image. Hyperspectral images and ground truth data were assessed with statistical, GIS and modeling tools, i.e. Vegetation Index (Normalized Difference Vegetation Index, Red Edge Normalized Difference Vegetation Index, Modified Red Edge Simple Ratio, Vogelmann Red Edge Index 1, and others.). The methods Backward Multiple Linear Regression and Principal Component Analysis (PCA) were used to develop prediction models for leaf nitrogen. These results will contribute to the development of rapid detection techniques of nutritional status in citrus groves, in order to reduce the sampling procedures for foliar analysis, which ...
Doutor
Gonzatto, Mateus Pereira. "Desenvolvimento e produção de citros em sistema agroflorestal." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2009. http://hdl.handle.net/10183/18913.
Full textThe citrus production in agroforestry systems (SAFs) may be an interesting alternative, specially for the benefits of moderated shadow to various physiological aspects of those. Moreover, the increment of biological diversity to the agroecosystem, when handled properly, can bring uncountable gains to organic production systems. With the objective to measure the effect of SAF over many aspects in the citrus production in comparison to the cultivation in full sun (SOL), a SAF of ‘Valencia’ and ‘Monte Parnaso’ oranges (Citrus sinensis (L.) Osb.) located in the municipality of Tupandi (in the Rio Grande do Sul State – Brazil) during the harvesting seasons of 2007 and 2008, with the superior canopy composed by angico-vermelho (Parapiptadenia rigida (Benth.) Brenan) where both treatments were under organic cultivation, was studied. For that, were evaluated the micrometheorological conditions of the culture environment; the vegetative development; the productive behavior and nutritional state; the growth, occurrence of diseases and ripening of fruits; the phenology and the quality characteristics of the orange trees flowering. The radiation reduction by the SAF was 36,2 % mean, without significant alterations to the temperature and relative humidity of the air on the fruit level. The fruit income, in the harvesting seasons mean, was superior under SAF for ‘Valencia’ orange and had no alterations for ‘Monte Parnaso’ orange. The intern maturation of fruits was delayed in both varieties under SAF, having a 20 days delay for ‘Valencia’ orange in both years. The pre-harvesting fall was higher for SOL treatment. The occurrence of phenological states was not affected by the treatments. There were alterations on the quality of flowering for ‘Monte Parnaso’ orange, yet the fruit fixation wasn’t influenced. Some nutrients had their leaf content raised (Mn, Fe and N), while others were reduced (B and P) due to the cultivation under SAF. The incidence and severity of the black-spot (Guignardia citricarpa Kiely) were reduced in 17 % and 46 % respectively on the fruits under SAF, having a greater occurrence of premature fruit drop (Colletotrichum acutatum Simmonds) in this treatment however.
Prato, Sarmiento Andrés Iván. "Multiplicação de porta-enxertos de citros por estaquia." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/129452.
Full textThe Brazilian citrus industry is characterized by a low diversification of rootstocks. The genetic diversification of these is a crucial strategy for the sustainability of the Brazilian citrus industry. Some citrus rootstocks are at risk of genetic segregation if are propagated sexually, due to the low apomixis. The vegetative production eliminates this risk. The work aimed to study the rooting potential of cuttings of tangerine ‘Sunki’ and its hybrids H49, H77 and H92, evaluating two seasons of collecting (autumn and late spring), concentrations of indolebutyric acid (0, 750, 1.500 and 3.000 mg L-1), presence or absence of leaves and culture conditions of mother plant (field e greenhouse). The mother plant trees from which the plant material was collected are grown in the Agricultural Experimental Station – Universidade Federal do Rio Grande do Sul, located in the municipality of Eldorado do Sul, RS – Brazil (30° 06’ S, 51° 39’ W). After of period in greenhouse with intermittent mist system, the results of the experiments indicate the cuttings of ‘Sunki’' mandarin collected from the mother plant cultivated in the field in late spring (17/12/2013) showed higher values for all variables in relation to those plants kept under greenhouse conditions. The IBA was only effective in collected cuttings of plants kept in a greenhouse conditions. Rooting was high (> 90%) regardless of the mother plant cultivation condition. However, in autumn collection (04/14/2013,) the response was low (14%), even at a concentration of 3.000 mg L-1 with the plant growth regulator (23%). Maintaining leaves in cuttings was essential for rooting and sprouting. In the case of hybrids, the fall collection was lower rooting on H77 (10.2%) and higher in H49 (18.3%), but being unnecessary the use of plant growth regulator in late spring. The mother plants had higher total reserves of content on the stem and lower on the leaves in late spring in both genotypes. After 11 months of transplanting the rooted cuttings in plastic bags (4,5 L) high survival (80%) and also growth vegetative of the H49 and H77 hybrid were found. About 50% of these seedlings were able to grafting. The collection of cuttings in late spring is best suited for propagation of tangerine 'Sunki' and its hybrids by cuttings.
Silva, Silvokleio da Costa. "Homeologia e evolução dos cromossomos marcadores dos citros." Universidade Federal de Pernambuco, 2012. https://repositorio.ufpe.br/handle/123456789/12749.
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CNPq
Recentemente, um mapa citogenético estabelecido para Poncirus trifoliata disponibilizou marcadores cromossomo-específicos para estudos evolutivos das espécies cítricas. Objetivando reconhecer as homeologias cromossômicas e entender as alterações cariotípicas existente entre os gêneros Poncirus e Citrus e entre os principais representantes dos citros, os mapas citogenéticos de P. trifoliata cv. Flying Dragon, C. reticulata cv. Cravo (tangerina) e C. maxima cv. Pink (toranja) foram construídos e comparados entre si e com o mapa previamente estabelecido para C. medica var. Etrog (cidra). Os cromossomos marcadores de P. trifoliata também foram mapeados em C. sinensis (L.) cv. Valencia (laranjeira doce), o principal híbrido de interesse econômico do grupo. Metáfases mitóticas destas espécies foram coradas com os fluorocromos CMA e DAPI e submetidas a hibridização in situ fluorescente (FISH) empregando sondas de cromossomos artificiais de bactérias (BACs) e de DNAr 5S e 45S. As fórmulas cariotípicas encontradas para as cultivares analisadas de P. trifoliata (4B+8D+6F), C. reticulata (2C+10D+6F), C. maxima (4A+2C+4D+8F) e C. sinensis (2B+2C+7D+7F) corroboram com as anteriormente reportadas na literatura, entretanto, um pequeno sítio proximal adicional de DNAr 45S foi detectado em C. reticulata. Apenas os cromossomos 1, 4 e 8 foram conservados quanto ao tipo cromossômico e localização dos BACs entre as espécies estudadas. Nos demais casos, as posições dos BACs foram conservadas, mas não os tipos cromossômicos. Quebra de colinearidade foi observada apenas no par 3, entre BACs e um sítio de DNAr 45S, sugerindo que inversões ou transposições também podem ter ocorrido. Os resultados aqui reportados indicam uma alta sintenia no grupo. As principais divergências cariotípicas observadas provavelmente estão relacionadas a eventos de amplificação e/ou desamplificação de sequências repetitivas que compõem os blocos CMA+. Essas alterações foram mais frequentes em C. medica que nas demais espécies, porém, considerando a variabilidade encontrada, as semelhanças cariotípicas observadas entre espécies filogeneticamente distantes podem ser fruto de reversões e não da conservação de um cariótipo ancestral. Os dados de mapeamento dos BACs nos pares cromossômicos 2 e 3 de C. sinensis, associados aos seus tipos cromossômicos, corroboram toranja e tangerina como os prováveis parentais deste híbrido.
Marques, Léo Omar Duarte. "Avaliação inicial de potenciais porta-enxertos de citros." Universidade Federal de Pelotas, 2018. http://guaiaca.ufpel.edu.br:8080/handle/prefix/4092.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
As doenças são um dos principais problemas para a cultura do citros no Brasil, o fato do Rio Grande do Sul ter sua citricultura concentrada sobre um único porta-enxerto („Trifoliata‟) aumenta e muito os riscos fitossanitários, em uma possível disseminação de doenças que esse porta-enxerto apresente suscetibilidade. Existe uma grande necessidade de diversificar a base genética de porta-enxertos cítricos no estado do Rio Grande do Sul, que pode ser resolvida através de estudos de genótipos que se adaptem às condições climáticas do estado. Objetivou-se avaliar o desenvolvimento e adaptação de diferentes porta-enxertos, desde a fase de emergência de sementes até o período que antecede a enxertia. A dissertação traz um artigo, elaborado nos anos de 2016 e 2017, na unidade Sede da Embrapa Clima Temperado em Pelotas-RS. Intitulado “Desenvolvimento inicial de potenciais porta-enxertos para a citricultura”, analisa o comportamento dos porta-enxertos no período em que às sementes estão emergindo, analisando às variáveis porcentual da emergência de plântulas, início, duração e uniformidade de emergência e também o crescimento, através das variáveis altura e diâmetro medidos a partir dos 130 dias após a semeadura e a adaptação às condições climáticas locais através do porcentual de mortalidade. Verificou-se que os porta-enxertos „Trifoliata‟, TSKC X CTSW – 041 e TSKC X CTSW – 025 apresentam sementes com maior emergência de plântulas, e que o „Trifoliata‟ manifesta emergência mais precoce, rápida e uniforme, em comparação aos demais porta-enxertos utilizados no experimento. Foi possível observar que muitos porta-enxertos não se desenvolveram bem nas condições de clima local, como por exemplo, os genótipos LCR X CTSW – 009 e LVK X LCR – 039, que tiveram 100% e 90% de plantas mortas respectivamente. Por outro lado verificou-se que alguns genótipos adaptaram-se perfeitamente, o porta-enxerto citrumeleiro „Swingle‟, apresentou maior altura e diâmetro associado a uma mortalidade muito baixa, outros porta-enxertos além do citrumeleiro „Swingle‟ são promissores para citricultura do estado devido ao um desenvolvimento inicial superior e uma baixa mortalidade, como os genótipos Cleo X TRBN – 245, Cleo X TRSW – 287, citrandarins „Índio‟, „San Diego‟ e „Riverside‟, LRF X (LCR X TR) – 005 e limoeiro „Cravo‟.
The diseases are one of the main problems for the citrus crop in Brazil, the fact that Rio Grande do Sul has its citriculture concentrated on a single rootstock ('Trifoliata') increases the phytosanitary risks, in a possible dissemination of diseases that this rootstock is susceptible. There is a great need to diversify the genetic basis of citrus rootstocks in the state of Rio Grande do Sul, which can be solved through studies of genotypes that adapt to the climatic conditions of the state. The goal of this study was to evaluate the development and adaptation of different rootstocks, from seed emergence to the period that preceds the grafting. The dissertation brings an article, elaborated in the years 2016 and 2017, at the headquarters of Embrapa Clima Temperado in Pelotas-RS . Entitled "Initial development of potential rootstocks for citrus", analyze the behavior of the rootstocks in the period in which the seeds are emerging, through the variables: seedling emergence percentage, iniciation, duration and emergency uniformity, as well as growth, through the variables of height and diameter measured from 130 days after sowing and adaptation to local climatic conditions by mortality rate. It was verified that Trifoliata rootstocks, TSKC X CTSW-041 and TSKC X CTSW-025, showed seeds with higher seedling emergence, and that 'Trifoliata' showed premature emergence, faster and more uniform compared to the others. It was possible to observe that many rootstocks did not develop well under local climatic conditions, such as the LCR X CTSW-009 and LVK X LCR-039 genotypes, which had 100% and 90% of dead plants respectively. On the other hand, it was verified that some genotypes were perfectly adapted, the 'Swingle' citrus tree rootstock, presented higher height and diameter associated with a very low mortality, other rootstocks besides the 'Swingle' citrus tree are promising for citrus cultivation of the state due to superior initial development and low mortality, such as the genotypes Cleo X TRBN - 245, Cleo X TRSW - 287, citrandarins 'Índio', 'San Diego' and 'Riverside', LRF X (LCR X TR) - 005 and lemon tree 'Cravo'.
Lima, Jorge Facà Franklin de. "Modelos de simulaÃÃo na anÃlise antitruste: aplicaÃÃo na fusÃo entre General Motors e PSA Peugeot Citroen." Universidade Federal do CearÃ, 2012. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=11024.
Full textEsta dissertaÃÃo apresenta uma anÃlise de simulaÃÃo de fusÃo no mercado brasileiro de automÃveis. O objetivo central da anÃlise à computar os efeitos da fusÃo entre a General Motors e a PSA Peugeot CitroÃn, apÃs o anÃncio da criaÃÃo de uma AlianÃa EstratÃgica Global entre as duas empresas. Os resultados do equilÃbrio pÃs-fusÃo sÃo simulados pelo modelo PCAIDS (Proportionality-Calibrated Almost Ideal Demand System), proposto por Epstein e Rubinfeld (2002), que simula a fusÃo de duas empresas em um mercado oligopolizado. Os resultados do exercÃcio de simulaÃÃo confirmaram os aumentos esperados nos preÃos dos produtos. Este resultado à condizente com a expectativa de que as fusÃes implicam em aumentos de preÃos de mercado e, sem ganhos de eficiÃncia econÃmica, podem impor perdas para os consumidores.
This dissertation presents a simulation analysis of fusion in the Brazilian automobile. The central objective of the analysis is to compute the effects of the merger between General Motors and PSA Peugeot CitroÃn, after the announcement of the creation of a Global Strategic Alliance between the two companies. The results of the post-merger equilibrium are simulated PCAIDS (Proportionality-Calibrated Almost Ideal Demand System), proposed by Epstein and Rubinfeld (2002), which simulates the merger of two firms in an oligopoly market. The results of the simulation exercise confirmed the expected increases in product prices. This result is consistent with the expectation that mergers involve increases in market prices and without economic efficiency gains, impose losses for consumers.
Lima, Jorge Facó Franklin de. "Modelos de simulação na análise antitruste: aplicação na fusão entre General Motors e PSA Peugeot Citroen." reponame:Repositório Institucional da UFC, 2013. http://www.repositorio.ufc.br/handle/riufc/9483.
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This dissertation presents a simulation analysis of fusion in the Brazilian automobile. The central objective of the analysis is to compute the effects of the merger between General Motors and PSA Peugeot Citroën, after the announcement of the creation of a Global Strategic Alliance between the two companies. The results of the post-merger equilibrium are simulated PCAIDS (Proportionality-Calibrated Almost Ideal Demand System), proposed by Epstein and Rubinfeld (2002), which simulates the merger of two firms in an oligopoly market. The results of the simulation exercise confirmed the expected increases in product prices. This result is consistent with the expectation that mergers involve increases in market prices and without economic efficiency gains, impose losses for consumers.
Esta dissertação apresenta uma análise de simulação de fusão no mercado brasileiro de automóveis. O objetivo central da análise é computar os efeitos da fusão entre a General Motors e a PSA Peugeot Citroën, após o anúncio da criação de uma Aliança Estratégica Global entre as duas empresas. Os resultados do equilíbrio pós-fusão são simulados pelo modelo PCAIDS (Proportionality-Calibrated Almost Ideal Demand System), proposto por Epstein e Rubinfeld (2002), que simula a fusão de duas empresas em um mercado oligopolizado. Os resultados do exercício de simulação confirmaram os aumentos esperados nos preços dos produtos. Este resultado é condizente com a expectativa de que as fusões implicam em aumentos de preços de mercado e, sem ganhos de eficiência econômica, podem impor perdas para os consumidores.
Pereira, Juliana Aparecida. "Resposta de genótipos de citros à leprose e variabilidade genética da ORF p29 do vírus da leprose dos citros C (CiLV-C)." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/11/11138/tde-31052012-082524/.
Full textViruses have, potentially, broad genetic variability because of their need to adapt to several changes that they are exposed to. Therefore, genetic variability is essential for their survival; it is the first step to adapt to a new host, to break resistance down, to change symptoms and virulence, which justifies the interest in studies in this area. These studies consist in a great tool for a better understanding on the virus evolution and the search for a proper management of viral diseases. Hence, it was aimed to study the genetic variability of ORF p29 from CiLV-C in order to generate relevant information about the pathosystem and the predominance of isolates with possible implications on the epidemiology of the disease and its management in the field, besides a better understanding on the evolution of this virus, which has never been explored before. In this work, we evaluated citrus plants and potential hosts for CiLV-C. The results suggest that the plants of Cravo, Tardia da Sicília, Cleopatra, and Vermelha mandarin, Ortanique tangor, Sour orange and spiderwort are susceptible to the disease and can also serve as sources of inoculum of the virus to citrus. Siciliano lemon, Rangpur, Tahiti, and Mexican limes, and Mimosa caesalpiniaefolia were resistant to the disease, but not to the colonization of the mite vector. Malvaviscus arboreus and Solanum violaefolium plants did not present symptoms, but can be considered possible sources of CiLV-C inoculum to citrus plants. In addition, we evaluated the response of 62 mandarin genotypes and their hybrids to the disease. Fifteen of them were considered resistant and could be used in breeding programs with the objective to reduce the use of pesticides to control the vector. Low genetic variability was found amongst CiLV-C isolates, regardless of the host or geographic region; however, the São José do Rio Preto isolate was the most divergent and the changes in nucleotides were transmitted to the other hosts. Further studies should be conducted before unquestionable conclusions can be drawn from this issue, but the results obtained here have opened a new range of possibilities for future studies in this area so far almost unexplored.
Zaghi, Ana Flávia. "Diagnóstico de doenças de citros utilizando espectroscopia de fluorescência." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/75/75132/tde-25082009-082437/.
Full textCurrently the largest portion of money applied to citriculture focus on health of the orchard. The phytosanitary costs, along with fertilizers, exceed 60% of the production cost. The control of diseases such as Sudden Death of Citrus (SDC), Decline and Greening, also known as Huanglongbing, is done by visual inspection, which confers to the method a high level of subjectivity and imprecision. This work was intended to develop a quick and safe methodology of diagnosis for the diseases mentioned above using fluorescence spectroscopy and laser-induced fluorescence (LIF). It was used in this study two rootstocks, Cravo and Cleopatra, and four varieties of crown: Pera, Natal, Valencia and Hamlin. The diseases studied were also classified into different levels of severity. The index 1 was used for low severity SDC, and 2 for a more advanced stage of this disease. For Greening has been made a distinction between symptomatic and asymptomatic leaves. The Decline of Citrus disease was also part of this study because its symptoms are very similar to those in the initial phase of SDC, and this is a serious problem for the evaluation of contamination in the field. Initially, studies have been made on the fluorescence of photosynthetic pigments from the extracts of ill and healthy leaves using a non-portable fluorimeter. For the leaf analyses we used a portable system of laser-induced fluorescence spectroscopy developed in LOLEIA. The study of extracts revealed that the largest cariations occur in the concentrations of chlorophyll a and b, and that acessory pigments like ? and ?-carotones do not fluoresce in the wavelength used. In general, it is possible to say that ill plants have a decrease of chlorophylls a e b. The leaf results were analyzed through the statistical method Principal Component Analysis (PCA) in order to facilitate the observation of spectral changes. Through the developed methodology it was possible to identify and distinguish the diseases with efficiency greater than 93%. However, these results contributed for the development of a methodology for diagnosis of citrus diseases in a quick, accurate and economically viable way.
Luchiari, Danilo Jose Fanelli. "Estudo da repartição das chuvas em cultura de citros." [s.n.], 1989. http://repositorio.unicamp.br/jspui/handle/REPOSIP/258155.
Full textDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Limeira
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Resumo: O presente trabalho teve como objetivo o Estudo da Repartição das Chuvas em Cultura de Citros. A pesquisa foi implantada num pomar comercial de citros de variedade valência, localizada na Fazenda Amazomas I, no município de Leme - S.P.. Determinaram-se as relações porcentuais entre a precipitação bruta sobre a cultura (PB) e as parcelas que atingem o solo através da precipitação interna (PI) e do escoamento pelo caule (EC), que somadas geram a precipitação efetiva (PE). Dessa forma determinou-se também a quantidade de água interceptada pela copa das plantas e evaporada para a atmosfera (I). A pesquisa foi implantada no meio do pomar utilizando quatro estações, cada qual composta de uma árvore. Em cada estação foram instalados 40 micro pluviômetros radialmente distribuídos e um coletor de escoamento pelo caule. A pesquisa foi implantada em novembro de 1985 e encerrada em julho de 1988, nesse período foram coletados 70 dados, perfazendo 3072,54mm de precipitação bruta. Os dados de cada evento analisados, permitiram obter a seguinte relação de repartição de chuvas em laranjeiras valência:precipitação interna(PI) = 79 %, escoamento pelo caule (EC) = 4%, precipitação efetiva (PE) = 83% e lnterceptação (I) = 17%. Aplicando-se o método de análise de regressão, obtiveram-se as seguintes equações: PE = - 2,515 + 0,882 PB ; r = 0,987 PI = - 2,818 + 0,847 PB ; r = 0,985 EC = + 0;303 + 0,034 PB ; r = 0,887
Abstract: This work had as goal the partitial rainfall in citrus plantation. The research took place in a commercial orchard of "valencia" citrus, from the "Fazenda Amazonas 1" farm, in Leme S.P.. It was determined the perceptual relationships between the rainfall over the crop (PB) and the fractions which find the soil internal rainfall fraction (PI) and the stem flow CEC), whose added give the effective rainfall (PE). In this way it was also determined the amount of intercepted water by the crown foliage and that which evaporate to the atmosphere (1). The research was done in the middle of the orchard using four sets of measurements, each one composed of one tree. In each set was installed 40 micropluvlometers distributed radially and one stemflow collector. The research lasted from November, 1986 to july, 1988 and during this time was taken 70 data, given then 3072,54 mm of rainfall (PB). The data of each analysed event allowed to find the following relationship of the partitial rainfall in " valencia" citrus: internal rainfall (PI) = 79%, stemflow (EC)= 4%, effective rainfall (PE) = 83% and interceptation (I) = 17%. Applying the regression analyses method, it gets the following equations: PE = - 2,515 + 0,882 PB ; r = 0,987 PI = - 2,818 + 0,847 PB ; r = 0,985 EC = + 0;303 + 0,034 PB ; r = 0,887
Mestrado
Mestre em Engenharia Civil
Cardinali, Marcelo Camponez do Brasil. "Diagnóstico de Huanglongbing (HLB) em citros utilizando técnicas fotônicas." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-22082012-083337/.
Full textSweet orange is one of the most produced and consumed fruit in the world, and Brazil is the largest producer and exporter of this fruit. However, pests and diseases significantly reduce the worldwide production. Currently, the most destructive disease in the field is called greening, also known as huanglongbing (HLB). There is no control for HLB. In addition, the disease presents a long asymptomatic phase. Furthermore, no diagnostic methods are available to use in large scale. In this study are proposed fluorescence and infrared spectroscopy for the HLB diagnosis. For the measurements were collected leaves from healthy, HLB- and citrus variegated chlorosis-infected plants, being the last one to comparison between the diseases. It were collected four classes of leaves: healthy, HLB-asymptomatic, HLB-symptomatic and CVC-symptomatic. The leaves were measured and their spectra were pre-processed for the induction of classifier via partial least squares regression. In addition, samples of plant metabolites were measured for leaves spectral interpretation: starch, glucose, sucrose, hesperidin, naringin and umbelliferone. Success rates above 89% were obtained through both photonic techniques, higher compared to the sucess rates of the actual management methods. The metabolites spectra have shown strong evidence that their concentrations changes could contribute to the diagnosis of the diseases by photonic techniques. Particularly, the fluorescence spectroscopy seems interesting because it has a great potential for field application due to the existence of portable photonic devices.
Adami, Andréia Cristina de Oliveira. "Risco e retorno de investimento em citros no Brasil." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/11/11132/tde-24052010-110330/.
Full textThe brazilian citrus industry has seen as a reasonably profitable business in the long term, but characterized by worrying level of risk. This study below aimed to evaluate the profitability and risk of this business, suggesting that the best to manage them is the provision of resources. Net Present Value - NPV was the method used to confront risk and return of citrus industry. Identification of the main factors (sources of risk) that may cause the variability of cash flows was made by examining accounts of cash flow activity and estimating vector autoregression forecast prediction to define joint distributions. Productivity distributions in 19-year life of orchad were adjusted by Kolmogorov-Smirvov test. Using NPV model were simulated 10,000 possible values for risk factors which replaced in accounts of the cash flow generates 10,000 possible values to business return. Orange orchard investment analysis showed that the major risk factors for citrus are: prices received by fruit, prices paid for inputs and productivity of plants. The investment has been shown economically feasible based on a discount rate of 4% per year, with chance of 0.01% to get NPV <0, 16% chance of getting NPV <0 using a discount rate of 6% per year and using a discount rate of 8% per year the investment becomes economically unfeasible, it means only 3% chance of getting NPV> 0. Although the expected average return has been shown profitable (6.6% per year), producers may need resources to support negative cash flow years. In order to manage project risks, we suggest two procedures to calculate the provision: a risk-based on NPV <0 and distribution of accumulated capitalized and negative net income values. Provision value to protect the producer against 95% of possible annual deficits represents 17% of first 3 years investment value. However, the total amount to be provisioned will depend on investors further resources available to apply in the project or based on credit limit available to cover cash deficits.
Terencio, Jean Carlos Corte. "\"Detecção precoce da morte súbita dos citros usando fluorescência\"." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/75/75132/tde-11042007-104925/.
Full textCurrently, the diagnosis of citrus sudden death (CSD) is carried out by visual inspection and collection of the rootstock, which causes the method to be inaccurate and allows for much subjectivity, besides demanding much time to examine the infestation data. The present work intends to study changes in the physical and chemical properties resulting in CSD of leaves and rootstock material of sweet orange trees (Citrus (L.) Osbeck), as well as developing a new diagnosis methodology of the disease. Thus, leaves, rootstock and their extracts were analyzed by means of the following spectroscopic techniques: absorption of uv-visible light, absorption of infrared with Fourier transform, fluorescence and laser-induced fluorescence. Besides employing spectroscopic techniques, studies using fluorescence images of healthy and sick leaves were carried out. Samples of healthy leaves, sick leaves with CSD and sick leaves with citrus decline (CD) were collected. Comparison of these diseases is primordial since in the field the symptoms are similar, causing much confusion in the evaluation system of contamination. Significant changes were observed in the spectra of fluorescence emissions for the three types of samples and based on such differences an index capable of diagnosing CSD and CD was defined. The fluorescence image techniques also brought important information, thus allowing to quickly differentiate between healthy and sick leaves. Joining the technique of images with spectroscopy originated a new methodology of CSD, which is potentially much faster, precise and non-invasive, thus allowing in natura analysis of leaves.
Filho, Diógenes Ferreira. "Estudo de expressão gênica em citros utilizando modelos lineares." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/11/11134/tde-16032010-111945/.
Full textThis paper presents a review of the methodology of microarray experiments for its installation and statistical analysis of data obtained. Then this methodology is applied in data analysis of gene expression in citrus, generated by a macroarray experiment, using linear models with fixed effects considering the inclusion or exclusion of different effects and considering adjustments of models for each gene separately and for all genes simultaneously. The macroarray experiments are similar to the microarray experiments, but use a smaller number of genes. In general, are used due to economic restrictions. Because they have been used a few arrays in the experiment analyzed in this study it was used a empirical Bayes approach that uses estimates of variance more stable and that takes into account the correlation among replicates of the gene within array. A non parametric analysis method was also used to outline the problem of the non normality for some genes. The results obtained in each of the described methods of analysis were then compared.
Maciel, Iramá Lopes. "Status sanitário da mosca negra dos citros no Brasil." Universidade Federal de Viçosa, 2015. http://www.locus.ufv.br/handle/123456789/9562.
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A mosca negra dos citros, Aleurocanthus woglumi (Hemiptera: Aleuródida), é uma espécie exótica que coloniza plantas cítricas e que até recentemente possuía o status de praga quarentenária presente A2 de alerta máximo no país, restringindo o comércio de plantas e frutos cítricos de estados de regiões infestadas para estados sem a presença da praga. O primeiro registro da praga no Brasil ocorreu em maio de 2001, no Estado do Pará, e desde então parece ter havido rápida disseminação da praga para outros estados e regiões do país. Assim, o objetivo neste estudo foi avaliar o atual status sanitário da mosca negra dos citros no Brasil. Para a realização do trabalho, dados existentes em relatórios de levantamentos sobre a ocorrência da praga realizados pelos Órgãos Estaduais de Sanidade Vegetal foram compilados e analisados. Esses incluíram informações sobre diversas variáveis: danos que a mosca negra dos citros tem causado nas lavouras hospedeiras; culturas hospedeiras em que já foi constatado o ataque da praga; áreas de disseminação da praga nos municípios dos estados, considerando o atual sistema de produção nas regiões produtoras de plantas hospedeiras, e a existência de legislação estadual complementar a legislação federal a respeito do status sanitário da mosca negra dos citros. Os resultados obtidos mostram que os danos e prejuízos associados à praga e registrados nos levantamentos incluíam custos com pulverizações de inseticida e com certificação dos produtos para o trânsito e a redução da qualidade dos frutos devido à fumagina. As principais espécies de plantas hospedeiras da praga reportadas nos levantamentos foram citros e manga. Sobre a disseminação, sua presença foi constatada em 23 dos 27 Estados da Federação Brasileira, o que suporta a decisão de alteração do status da mosca negra dos citros de praga quarentenária presente (A2) no território nacional. Segundo os levantamentos, a praga se encontra disseminada nos Estados de MG, BA, MS, RN, CE, PR e PE, mas está ausente nas áreas de produção comercial de cultivos hospedeiros. Em SP e RJ, a praga está disseminada em parte do território desses estados com ocorrência em áreas de produção de espécies hospedeiras. Nos Estados de SE, ES e AL, a praga está presente em pequenos focos, e nos demais Estados, ela encontra-se presente em áreas de produção comercial e não comercial de plantas hospedeiras. A maioria dos estados adotava procedimentos da legislação federal para fiscalização quarentenária e somente os Estados de Minas Gerais, São Paulo, Bahia e Ceará possuem legislação estadual complementar à legislação federal.
The citrus blackfly, Aleurocanthus woglumi (Hemiptera: Aleyrodidae), is an exotic species that colonizes citrus plants and that until recently held the status of quarantine pest A2 of high alert in the country, restricting exchange of citric plants and fruits from states of regions with A. woglumi infestation to those in which the pest was absent. After being first recorded in Pará state in May 2001, the pest seemed to have spread rapidly to other states and regions of the country. Hence, this studied was conducted to evaluate the current sanitary status of the citrus blackfly in Brazil. Data were collected from existing survey reports on the occurrence of pest performed by State Agencies of Animal Plant Health Inspection were compiled and analyzed. These included information on several variables: injury and losses caused by the citrus black fly in host crops; host crops in which pest attack was recorded; dissemination areas in counties of the states considering current production system in regions growing host plants, and finally the existence of state-level legislation complementary to the federal legislation regarding the status of citrus black fly. The results obtained show that injury and losses associated with the pest included costs of insecticide sprays, product certification for transit, and reduced quality of fruits due to the sooty mold as reported in the surveys. Citrus and mango were the main host-plant species of A. woglumi reported in the surveys. Regarding the pest spread, its presence was detected in 23 of the 27 States of the Brazilian Federation, which supports the decision to have changed the quarantine status of the citrus black fly (A2) in the national territory. According to the surveys, the pest is widespread in the States of MG, BA, MS, RN, CE, PR, and PE, but it is absent in the areas of commercial production of host crops. The pest is present in some counties of the states of SP and RJ, with occurrence in areas where host species are grown commercially. In the states of SE, ES, and AL, the pest is present in patches in low infestation levels, and in the other states, it is present in areas of commercial and non-commercial host-plant production. Most states adopted the federal legislation procedures for quarantine surveillance, and only the states of Minas Gerais, São Paulo, Bahia and Ceará have state-level legislation complementary to the federal legislation.
Mauricio, Fernanda Nara. "Análise da expressão de genes relacionados à defesa em novos híbridos de citros resistentes à Clorose Variegada dos Citros e mapeamento de eQTL." Universidade Federal de São Carlos, 2013. https://repositorio.ufscar.br/handle/ufscar/21.
Full textBrazil is the largest producer of sweet orange, but the productivity is not the highest due to disease problems. A major problem is the Citrus Variegated Chlorosis (CVC) caused by the bacterium Xylella fastidiosa, which promotes obstruction of the xylem, causing physiological disorders in plant and in advanced cases, affecting fruits, leading to production losses. In this study, hybrids obtained from controlled crosses between Murcott tangor [Citrus reticulata Blanco x Citrus sinensis (L.) Osbeck] and Pera sweet orange [Citrus sinensis (L.) Osbeck] were evaluated by analysis of symptoms, diagnosis through conventional and real time PCR (Polymerase Chain Reaction) , showing seven resistant hybrids, twenty-four tolerant hybrids and six susceptible hybrids. The expressions of thirteen genes [NBS-LRR - RGH1, Abscisic Acid (ABA), Thaumatin, Chitinase, Xa21 Kinase, Kinase CHRK1, Isoflavone Synthase, Protein Defense-Related Resistance - DRRP, No Product Set - SPD, Isoflavone Reductase, HCr2-0A, Ankyrin, Glutathione GST-22 associated with resistance were evaluated, and it was possible to relate the resistance to X. fastidiosa with gene expression. QTL (Quantitative Trait Loci) were mapped through the quantification of symptoms and bacterial concentration and expression QTL (eQTL) of genes were carried out with the evaluation of thirty-seven hybrids.
O Brasil é o maior produtor mundial de laranja, mas não apresenta maior produtividade devido a problemas fitossanitários. Um dos principais problemas é a Clorose Variegada dos Citros (CVC) causada pela bactéria Xylella fastidiosa, que promove a obstrução do xilema, causando desordens fisiológicas na planta e em casos avançados, afetando os frutos. A CVC acomete as variedades de Citrus sinensis (L.) Osbeck, conhecidas como laranjas-doce, sobre diferentes porta-enxertos, todavia não são encontrados sintomas em tangerinas e híbridos comerciais. Neste estudo, os híbridos obtidos a partir de cruzamentos controlados entre tangor Murcott [Citrus reticulata Blanco x Citrus sinensis (L.) Osbeck] com laranja Pera [Citrus sinensis (L.) Osbeck] foram avaliados através da análise dos sintomas, o diagnóstico por meio de PCR (Polymerase Chain Reaction) convencional e em tempo real, mostrando sete híbridos resistentes, vinte e quatro híbridos tolerantes e seis híbridos suscetíveis. As análises de expressões dos genes (NBS-LRR RGH1, Ácido Abscísico, Taumatina, Quitinase, Quinase Xa21, Quinase CHRK1, Isoflavone Sintase, Proteína de Defesa Relacionada com Resistência - PDRR, Sem Produto Definido - SPD, Isoflavona Redutase, HCr2- 0A, Anquirina e GST22) possibilitaram entender a relação entre a resistência a X. fastidiosa e a expressão gênica. Foram mapeados QTLs (Quantitative Trait Loci) através da quantificação de sintomas, concentração de bactérias. Baseados em um conjunto de resultados, foram detectados eQTLS (QTLs de expressão) de genes avaliados em trinta e sete híbridos.
Jahnke, Simone Mundstock. "Parasitóides de Phyllcnistis citrella stainton (Lepidóptera: gracillariidae) em pomares de citros em Montenegro, RS." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2004. http://hdl.handle.net/10183/4311.
Full textJungas, Thomas. "Caractérisation du rôle de la signalisation Eph-éphrine dans la division cellulaire." Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30102/document.
Full textCells within an organism successfully divide to ensure growth, differentiation and homeostasie. Recent work suggests that dividing cells actively communicate with neighbours thus spatially and temporally coordinating cell division while maintaining tissue cohesiveness. We hypothesized that Eph-ephrin signalling, a local cell-cell signalling pathway, could participate in coordinating cell division within a tissue. Using vertebrate and invertebrate cell culture models I showed that Eph-signalling controls cell division and induces delay in the abscission of nascent daughter cells as well as polyploidy. Using time-lapse imaging I proved that the Eph-mediated abscission failure depends on the catalytic activity of the receptor via the non receptor tyrosine kinase relay molecule c-Src. Downstream of Eph signalling c-Src phosphorylates the protein citron kinase (CitK) a well known regulator of intercellular bridge stability. I also observed that CitK was abnormally localized during cytokinesis when Eph signalling was active. Further, using in vitro kinase assays, I demonstrated that Eph does not directly phosphorylate CitK but that c-Src could do so. In addition, using Mass Spectrometry I mapped all tyrosine residues directly phosphorylated by c-Src. I mutated two of them located in the Rho binding domain of CitK and demonstrated that phosphorylation of those residues are necessary and sufficient to induce cytokinesis failure. I validated in vivo this novel role of Eph-ephrin signalling in a physiological context in the developing mouse neocortex. Members of the Eph/ephrin family are expressed in neural progenitors that give rise to neurons of the cortex upon neurogenic division. Importantly, CitK has been shown by others to control cytokinesis of these progenitor cells. Using the Cre-lox system, I specifically turned off Eph forward signalling in neural progenitor cells and observed an alteration of neuronal ploidy in these mutant animals. Further, I also observed that CitK which adopts a particular apical localisation in neural progenitors physiologically co-localized with phosphorylated tyrosine residues. Altogether, these results suggest that Eph-ephrin signalling controls abscission of neural progenitors by promoting phosphorylation of CitK. The textbook view of cytokinesis is that it is a cell autonomous event orchestrated by the intracellular machinery. Data obtained during my PhD suggest that cytokinesis is also regulated by local environment, here Eph/ephrin signalling, and that phosphorylation of CitK may represent a molecular switch in the normal progression of cell division and in the control of neuronal ploidy