Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-05-16T16:43:50Z No. of bitstreams: 1 VERLÂNIA FABÍOLA DE SOUSA FARIAS - DISSERTAÇÃO PPGSA PROFISSIONAL 2013..pdf: 942647 bytes, checksum: 70fe8770e6f2f71d2c0f3c1b41b05e2b (MD5) / Made available in DSpace on 2018-05-16T16:43:50Z (GMT). No. of bitstreams: 1 VERLÂNIA FABÍOLA DE SOUSA FARIAS - DISSERTAÇÃO PPGSA PROFISSIONAL 2013..pdf: 942647 bytes, checksum: 70fe8770e6f2f71d2c0f3c1b41b05e2b (MD5) Previous issue date: 2013-11-12 / O broto de palma surge no semiárido nordestino como uma hortaliça alternativa e potencial para o consumo humano, possibilitando a obtenção de produtos e alimentos ricos em nutrientes e antioxidantes. Assim, objetivou-se avaliar o desenvolvimento, a qualidade e a capacidade antioxidante em brotos de palma para o consumo humano. Os brotos foram colhidos nas primeiras horas do dia na área experimental do Centro de Ciências e Tecnologia Agroalimentar da Universidade Federal de Campina Grande, em Pombal - PB e avaliados quanto às variáveis físicas e químicas, utilizando-se o delineamento experimental inteiramente casualizado, no fatorial 2 x 4, sendo 2 cultivares (‘Gigante’ e ‘Redonda’) e 4 estádios de desenvolvimento (estádio 1 - brotos de 4,0 a 8,0 cm; estádio 2 - brotos de 8,01 a 12,0 cm; estádio 3 - brotos de 12,01 a 16,0 cm; estádio 4 - brotos de 16,01 a 20,0 cm), com seis repetições e 250 g por unidade experimental. Para as variáveis diâmetro longitudinal e transversal, massa fresca com espinhos, sem espinhos e dos espinhos e rendimento, houve um aumento significativo de seus valores com o estádio de desenvolvimento, com destaque para os brotos da cultivar ‘Redonda’. Os teores de proteínas, lipídeos e carboidratos reduziram significativamente com o avanço do desenvolvimento, para ambas as cultivares, assim como para a relação sólidos solúveis e acidez titulável e para o amido. Nos compostos bioativos clorofilas, carotenoides e flavonoides, os maiores teores foram encontrados no terceiro e quarto estádios da cultivar ‘Gigante’; já os polifenóis extraíveis foram maiores no primeiro e segundo estádios, dessa cultivar. Os teores de ácido ascórbico aumentaram com o estádio de desenvolvimento nas duas cultivares. A capacidade antioxidante foi superior na massa seca quando comparada à massa fresca, nos brotos de palma ‘Gigante’ e ‘Redonda’. Dessa forma, independente dos tratamentos avaliados, os brotos de palma exibiram características similares às de outras hortaliças, constituindo-se como fonte de compostos com propriedades antioxidantes, podendo ser usados como hortaliça em qualquer estádio de desenvolvimento, sendo que o terceiro e o quarto estádios foram os mais indicados, tanto para o consumo in natura como para o processamento agroindustrial. / The bud of palm comes in northeast semiarid as an alternative and potential vegetable for human consumption, making it possible to obtain products and foods rich in nutrients and antioxidants. Thus, the objective was to evaluate the development, quality and antioxidant capacity in palm buds for human consumption. The buds were harvested in the early hours in the experimental area of the Centre for Science and Agrifood Technology, Federal University of Campina Grande, in Pombal - PB and analyzed for physical and chemical variables, using a completely randomized design in a factorial 2 x 4, with 2 cultivars (‘Giant’ and ‘Round’) and 4 developmental stages (stage 1 - buds from 4,0 to 8,0 cm, stage 2 - buds from 8,01 to 12,0 cm, stage 3 - buds 12,01 to 16,0 cm, stage 4 - buds from 16,01 to 20,0 cm), with six replicates of 250 g per experimental unit. For longitudinal and transverse diameter variables, fresh pasta with thorns, without thorns and spines and income, there was a significant increase in their values with the stage of development, with emphasis on the buds of the cultivar ‘Round’. The levels of proteins, lipids and carbohydrates significantly decreased with advancing development, for cultivars, as well as the soluble solid and titratable acidity and starch. Bioactive compounds in chlorophylls, carotenoids and flavonoids, the highest levels were found in the third and fourth stages of cultivar ‘Giant’; have extractable polyphenols were higher in the first and second stages, this cultivar. The levels of ascorbic acid increased with the stage of development in both cultivars. The antioxidant capacity was higher in dry weight when compared to fresh weight in buds palm ‘Giant’ and ‘Round’. Thus, regardless of the treatments, the shoots palm exhibited similar to other vegetables, constituting a source of compounds with antioxidant characteristics, can be used as a vegetable in any stage of development, and the third and fourth in stars were the most suitable for both fresh consumption and for the agro-processing.

Made available in DSpace on 2014-08-20T14:33:11Z (GMT). No. of bitstreams: 1 Dissertacao_Rafael_Ucker_Brahm.pdf: 2089912 bytes, checksum: 8700b9d818a6d894ba0f1cd729523bd8 (MD5) Previous issue date: 2010-12-22 / The growth of the species of juçara palm Tree Euterpe edulis (Mart.) and royal palm Roystonea regia (Kunth) has no record of studies focusing on south region of Rio Grande do Sul State. It is necessary to identify a system that ensures the proper growth of plants of these species. In this context, these works provide alternatives for producing seedlings with adaptability for family farms of southern half of Rio Grande do Sul. The effect of different substrates on initial growth of the seedlings and the appropriate level of shading for their initial development were determined. The seedlings were grown on Estação Experimental Cascata, Embrapa Clima Temperado. The experiments reported in Chapters I determine the effect of different substrates. The seedlings grew from seeds originated in a family farm located in the municipalities of Tabai and Pelotas, RS. A combination of different substrates was used, represented by the treatments T1 - Plantmax®, T2 - forest soil, T3 - clayey soil, T4 - forest soil:clayey soil 1:1 (v:v), T5 - forest soil:carbonized rice husk 3:1 (v:v), T6 - forest soil:carbonized rice husk 1:1 (v:v), T7 - forest soil:rice husk in natura 1:1 (v:v), T8 - clayey soil:carbonized rice husk 3:1 (v:v), T9 - clayey soil:carbonized rice husk 1:1 (v:v), T10 - clayey soil:rice husk in natura 1:1 (v:v). The experimental design consisted of randomized blocks and the study used a (1 specie x 10 substrates) factorial scheme. Four replicates were used in each experimental design with four seedlings. The seedlings were transplanted into 2 dm³ plastic bags in greenhouse conditions, from January to September, 2009. The experiments were assessed fortnightly considering plants length, stem diameter, number of leaves, number of leaflets, leaflets length, roots length, physical properties of the substrates, macronutrients content of the substrates, and percentage of plants survival at the end of last evaluation. The experiments reported in Chapters II used plants grown from seeds of a family farm located in the municipality of Pelotas, RS. The effect of luminous intensity on palm trees growing in the field was assessed in the experiments. The palm trees were planted in different shading levels: S1 - 0%, S2 - 16%, S3 - 42% and S4 - 73%. 10 The shading was obtained with shade screen for each level of reduced incident radiant, it was placed over each plot represented by a structure of wooden beams with 2.10 m long, 0.70 m tall and 0.50 m wide. The experimental design was randomized blocks consisting of four replications. Each sampling unit was represented by three plants of each species, using 0.30 m row spacing, in the field during nine months. These experiments evaluated fortnightly plants length, stem diameter, number of leaves, number of leaflets, leaflets length, solar radiant incident on the plants, chlorophyll content of plants, roots length, soil physical properties, macronutrients content of soil, and percentage of survival at the end of last evaluation. Data were analyzed using the program statistical program WinSat. / O cultivo das espécies de palmeira-juçara Euterpe edulis (Mart.) e da palmeira-real Roystonea regia (Kunth) não possui registros de estudos focados para o Sul do Rio Grande do Sul, tornando-se necessário identificar um sistema com potencial para assegurar bom desenvolvimento das plantas destas espécies. Neste contexto, estes trabalhos forneceram alternativas de produção de mudas adaptadas à metade sul do Rio Grande do Sul, passível de utilização na agricultura familiar. Foi avaliado o efeito de diferentes substratos sobre o desenvolvimento inicial das mudas, bem como, identificou-se o nível de sombreamento adequado para o desenvolvimento inicial das mudas. Os trabalhos foram executados na Estação Experimental Cascata, Embrapa Clima Temperado. Para o Capítulo I, Estudos do efeito de diferentes substratos, utilizou-se plantas produzidas através de sementes em uma propriedade agrícola familiar localizada nos Municípios de Tabai-RS e Pelotas-RS. Foi utilizada a combinação de diferentes substratos representados pelos tratamentos: T1 - Plantmax®, T2 - solo mato, T3 - solo argiloso, T4 - solo mato:solo argiloso 1:1 (v:v), T5 - solo mato:casca de arroz carbonizada 3:1 (v:v), T6 - solo mato:casca de arroz carbonizada 1:1 (v:v), T7 - solo mato:casca de arroz in natura 1:1 (v:v), T8 - solo argiloso:casca de arroz carbonizada 3:1 (v:v), T9 - solo argiloso:casca de arroz carbonizada 1:1 (v:v), T10 - solo argiloso:casca de arroz in natura 1:1 (v:v). O delineamento experimental adotado foi de blocos ao acaso, com quatro repetições e cada unidade experimental composta por quatro plantas, sendo transplantadas para sacos plásticos de 2 dm3, em condições de casa de vegetação, no período de janeiro a setembro de 2009. Determinaremos para estes experimentos avaliar com intervalos quinzenais o comprimento das plantas; diâmetro do colo; número de folhas; número de folíolos; comprimento de folhas; comprimento das raízes; propriedades físicas dos substratos; teor de macronutrientes dos substratos; e 8 percentagem de sobrevivência das plantas ao final da ultima avaliação. Já para os experimentos Capítulo II, utilizou-se plantas produzidas através de sementes de uma propriedade familiar localizada no Município de Pelotas-RS, avaliado o efeito da intensidade luminosa sobre o desenvolvimento das palmeiras a campo, sendo estas plantadas em diferentes níveis de sombreamento: S1 - 0%, S2 - 16%, S3 - 42% e S4 - 73% de sombreamento. Estes sombreamentos foram obtidos com tela de sombrite para cada nível de redução da radiação incidente, colocada sobre cada parcela representada por uma estrutura de caibros de madeira medindo 2,10 m de comprimento, 0,70 m de altura e 0,50 m de largura. O delineamento experimental adotado foi de bloco ao acaso, compostos por quatro repetições, sendo cada unidade amostral representada por três plantas de cada espécie com espaçamento de 0,35 m entre linha, durante nove meses a campo. Determinamos para estes experimentos avaliar com intervalos quinzenais o comprimento das plantas; diâmetro do colo; número de folhas; número de folíolos; comprimento folhas; radiação solar incidente sobre as plantas; teor de clorofila das plantas; propriedades físicas do solo; teor de macronutrientes do solo; e percentagem de sobrevivência das plantas ao final da ultima avaliação. Os dados obtidos dos experimentos Capítulos I e II foram analisados através do programa estatístico WinStat.

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Le système de sécrétion type VII (T7SS) présent chez les mycobactéries comporte cinq loci, nommés ESX-1 à ESX-5, chacun possédant leurs propres fonctions. Le système ESX-3, le plus conservé entre les espèces de mycobactéries, participe au transport du fer et à la sécrétion de protéines dont la protéine EsxH. EsxH interagit avec le système ESCRT dans le macrophage et contribue à la persistance de M. tuberculosis (Mtb) dans l’hôte. Afin de mieux comprendre le mécanisme du T7SS, nous avons surexprimé le locus ESX-3 de Mtb dans les organismes recombinants M. smegmatis et M. marinum. Nous avons purifié un coeur protéique partiel du complexe ESX-3 par chromatographie liquide de protéine rapide (FPLC) et déterminé différentes structures in vitro qui pourraient représenter son dynamisme par une analyse des particules individuelles. Nous avons localisé le complexe ESX-3 aux pôles chez M. marinum par microscopie de fluorescence (fLM) et microscopie super-résolution d’illumination de structure (SR-SIM). Finalement, nous avons reconstruit un modèle in vivo 3D de ce complexe en jumelant une technique de corrélation entre la microscopie par localisation photoactivée (PALM) et la tomographie électronique en conditions cryogéniques (cryo-ET). En jumelant nos structures in vitro et notre modèle in vivo, nous discutons d’un mécanisme possible du complexe ESX-3. Ces analyses pourront aussi supporter le criblage d’inhibiteurs potentiels pour traiter les infection mycobactériennes. / A novel, type VII secretion system (T7SS) was recently discovered in Mycobacteria. Five subsystems, called ESX-1 to ESX-5, have been identified, with the ESX-3 being the most conserved. The ESX-3 system is essential for growth and pathogenesis, and has been implicated in iron transport and secretion of effector proteins into the host. The secreted proteins are shown to prevent phagosome maturation by interacting with the ESCRT machinery of the macrophage. To characterize the structure and mechanism of secretion employed by the T7SS, we use the ESX-3 system from Mycobacterium tuberculosis (Mtb) and recombinantly express it in M. smegmatis and M. marinum cells. By combining Fast Protein Liquid Chromatography (FPLC) and Single Particle electron microscopy analysis, we have reconstructed several in vitro models that contain at least three of the ESX-3 cluster proteins and may represent the dynamic nature of the core complex. Using fluorescent light microscopy (fLM) and super-resolution structure illumination microscopy (SR-SIM), we localized the ESX-3 complex to the lateral pole in M. marinum cells. We also used super-resolution photoactivated localization microscopy (PALM) in correlation with cryo-electron tomography (cryo-ET) of whole M. marinum cells to localize and reconstruct an in vivo 3D model of the ESX-3 secretion system. By combining the single particle reconstructions and the cryotomography data, we discuss a possible mechanism of ESX-3 secretion. Such analysis may support future inhibitor screens to prevent mycobacterial infections.

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No description available.

Tesis por compendio / [EN] The management of Rhynchophorus ferrugineus (Coleoptera: Dryophthoridae), the worst threat for palm trees worldwide, consists in several preventive and curative techniques, but because of its low efficacy the insect still causes major economic and landscape losses. In order to define aspects that have facilitated its rapid dispersal and contribute to improving its management, the effects of vision and flight, which influence the mobility of R. ferrugineus, have been analysed. The chromatic preference of R. ferrugineus has been studied by analysing their captures in coloured bucket traps. Black traps capture the highest number of insects compared with the other colours studied, both when they contain olfactory attractants, as when these compounds are not used, demonstrating that colour by itself is a crucial attraction factor. Moreover, the spectral reflectance of studied colours and of some P. canariensis tissues has been analysed. The wavelength spectrum of black shows great similarity to that of fibres of P. canariensis, so this may be the reason why R. ferrugineus prefers this colour. Regarding sex ratio of the insect in traps, female captures are significantly greater in those baited with olfactory attractants. However, a higher number of female captures does not always occur when these compounds are not used. On the other hand, the study of sex ratio in natural populations of the insect demonstrates that the proportion is one female per male. Therefore, the greater number of captures of females in commercial traps is due exclusively to their greater attraction towards the olfactory attractants used. Another of the analysed aspects has been the flight potential of R. ferrugineus under laboratory conditions. In order to know more about the mobility of this insect, different parameters have been studied using a computer-monitored flight mill. The selected parameters used to define the R. ferrugineus flight potential have been the number of flights, total distance flown, longest single flight, flight duration, and average and maximum speed. Moreover, the influence of sex, body size, and age of the adults on the aforementioned parameters has been examined. R. ferrugineus sex does not have a significant effect on the compared flight parameters. The body size in females is significantly greater, but this does not influence their flight potential. A higher percentage of flight is observed for adults with an age range of 8-23 days old, compared to the 1-7 day old adults. However, age does not significantly influence their flight potential. By analysing the longest single flight undertaken by each adult, up to 63% of the insects can be classified as short-distance flyers (<500m), 27.3% as medium-distance flyers (500-5000m), and >9% as long-distance flyers (>5000m). Finally, the flight behaviour and dispersal of R. ferrugineus have been analysed under field conditions using the mark-release-recapture method. This test focused on detecting the influence of different factors, such as sex, temperature, relative humidity, and solar radiation, in the take-off and dispersal of the adult insects. Take-off probability of R. ferrugineus adults is significantly greater in males Moreover, this probability increases when temperature and solar radiation rise. Concerning the insect dispersal by flying, the number of recaptures is influenced by temperature, increasing significantly when this factor increases. Likewise, dispersal distances also increase significantly as temperatures rise. The insect tends to fly distances <500m (77.1% of recaptured adults), following the same tendency observed in studies performed using the flight mill. However, R. ferrugineus is able to travel up to 7km, being recorded under laboratory conditions a potential flight up to 20km. To conclude, dispersal time of the adults is very short (more than 90% of the adults were recaptured during the first 7 days), being significantly lower when relative humidity increases. / [ES] El manejo de Rhynchophorus ferrugineus (Coleoptera: Dryophthoridae), una de las peores amenazas para las palmeras en el mundo, se lleva a cabo mediante la aplicación de diversas técnicas de prevención y control, pero debido a la baja eficacia de éstas la plaga continúa causando importantes pérdidas económicas y paisajísticas. Para definir los aspectos que han intervenido en su dispersión y contribuir a mejorar su manejo, se ha analizado el efecto de la visión y el vuelo en la movilidad de los adultos de R. ferrugineus. Se ha estudiado la preferencia cromática mediante el análisis de sus capturas en trampas cubo coloreadas. Las trampas negras capturan el mayor nº de insectos en comparación con el resto de colores estudiados, tanto cuando contienen atrayentes olfativos como cuando no los contienen, demostrando que el color por sí mismo es un factor importante de atracción. Además, se ha analizado el espectro de longitud de onda de los colores estudiados y de diversos tejidos de P. canariensis. El espectro del color negro muestra gran similitud con el de las fibras de P. canariensis, es por esto por lo que R. ferrugineus podría presentar esta preferencia. En relación a la proporción de sexos en trampas que contienen atrayentes olfativos, las capturas de hembras son significativamente más elevadas. En cambio, sin éstos no siempre se produce un mayor nº de capturas de este sexo. Por otro lado, el estudio de la proporción de sexos en poblaciones naturales muestra una ratio de una hembra por macho. Por tanto, las mayores capturas de hembras en trampas se deben a una mayor atracción de éstas hacia los atrayentes olfativos. Otro aspecto estudiado ha sido el potencial de vuelo de R. ferrugineus bajo condiciones de laboratorio. Con la finalidad de conocer la movilidad de este insecto se han analizado diversos parámetros mediante la utilización de un molinillo de vuelo computerizado. Los parámetros estudiados han sido: nº vuelos, distancia total volada, vuelo más largo, duración del vuelo y velocidades media y máxima. Además, se ha analizado como influye el sexo, el tamaño del cuerpo y la edad de los adultos en dichos parámetros de vuelo. El sexo de R. ferrugineus no muestra un efecto significativo sobre los parámetros de vuelo comparados. El tamaño del cuerpo de las hembras es significativamente mayor, pero no influye estadísticamente en su potencial de vuelo. En adultos con edades de entre 8-23 días se observa un mayor porcentaje de vuelo que en aquellos con 1-7 días de edad. En cambio, la edad no influye significativamente sobre su potencial de vuelo. Al analizar el vuelo más largo, obtenemos que >63% de los insectos se clasifican como voladores de corta distancia (<500m), el 27.3% de media distancia (500-5000m), y >9% de larga distancia (>5000m). Finalmente, se ha analizado en campo el comportamiento de vuelo y dispersión de R. ferrugineus mediante la técnica de marcaje-suelta-recaptura. Este ensayo ha permitido estudiar la influencia del sexo, la temperatura (Tª), la humedad relativa y la radiación solar, en el despegue y dispersión de los adultos. La probabilidad de despegue de R. ferrugineus es significativamente mayor en machos. Además, esta probabilidad se incrementa cuando la Tª y la radiación solar aumentan. Respecto a la dispersión del insecto mediante el vuelo, el nº de recapturas se ve influenciado por la Tª, aumentando significativamente cuando ésta se incrementa. De la misma manera, las distancias de dispersión también se incrementan significativamente a media que lo hace la Tª. El insecto tiende a volar distancias <500m (77.1% de los adultos recapturados), siguiendo la misma tendencia observada en laboratorio. No obstante, R. ferrugineus es capaz de recorrer hasta 7km, llegando a registrarse vuelos potenciales en laboratorio de hasta 20km. Por último, el tiempo de dispersión de los adultos es muy corto (>90% se recapturaron en los 7 primeros días), reduciéndose / [CA] El maneig de Rhynchophorus ferrugineus (Coleoptera: Dryophthoridae), una de les pitjors amenaces per a les palmeres en tot el món, es porta a terme mitjançant l'aplicació de diverses tècniques de prevenció i control, però degut a la baixa eficàcia d'aquestes l'insecte continua causant importants pèrdues econòmiques i paisatgístiques. Per a definir els aspectes que han intervingut en la seua dispersió i contribuir a la millora del seu maneig, s'ha analitzat l'efecte que tenen la visió i el vol en la mobilitat dels adults de R. ferrugineus. S'ha estudiat la preferència cromàtica mitjançant l'anàlisi de les seues captures en trampes poal acolorides. Les trampes negres capturen el major nombre d'insectes en comparació amb la resta de colors estudiats, tant quan contenen atraients olfactius com quan no els contenen, demostrant que el color per ell mateix és un factor important d'atracció. A més, s'ha analitzat l'espectre de longitud d'ona dels colors estudiats i de diversos teixits de P. canariensis. L'espectre del color negre mostra gran similitud amb el de les fibres de P. canariensis, és per açò pel que R. ferrugineus podria presentar aquesta preferència. En relació a la proporció de sexes a les trampes que contenen atraients olfactius, les captures de femelles són significativament més elevades. En canvi, sense aquests no sempre es produeix un major nombre de captures d'aquest sexe. Per altra banda, l'estudi de la proporció de sexes en poblacions naturals demostra que la ràtio és d'una femella per mascle. Per tant, les majors captures de femelles en trampes es deuen a una major atracció d'aquestes cap als atraients olfactius utilitzats. Altre aspecte estudiat ha sigut el potencial de vol de R. ferrugineus sota condicions de laboratori. Amb la finalitat de conèixer la mobilitat d'aquest insecte s'han analitzat diversos paràmetres mitjançant la utilització d'un molinet de vol computeritzat. Els paràmetres estudiats han sigut: nombre de vols, distància total volada, vol més llarg, duració del vol i velocitats mitjana i màxima dels vols. A més, s'ha analitzat com influeixen el sexe, el tamany del cos i l'edat dels adults en dits paràmetres de vol. El sexe de R. ferrugineus no mostra un efecte significatiu sobre els paràmetres de vol comparats. El tamany del cos de les femelles és significativament major, però no influeix estadísticament en el seu potencial de vol. En adults amb edats d'entre 8-23 dies s'observa un major percentatge de vol que en aquells amb 1-7 dies d'edat. En canvi, l'edat no influeix significativament sobre el seu potencial de vol. En analitzar el vol més llarg, obtenim que més del 63% dels insectes es classifiquen com voladors de curta distància (<500m), el 27.3% de mitja distància (500-5000m), i >9% de llarga distància (>5000m). Finalment, s'ha analitzat en camp el comportament de vol i dispersió de R. ferrugineus mitjançant la tècnica de marcatge-solta-recaptura. Aquest assaig ha permès estudiar la influència del sexe, la temperatura, la humitat relativa i la radiació solar, en l'enlairament i dispersió dels adults. La probabilitat d'enlairament de R. ferrugineus és significativament major en mascles A més, aquesta probabilitat s'incrementa quan la temperatura i la radiació solar augmenten. Respecte a la dispersió de l'insecte mitjançant el vol, el nombre de recaptures es veu influenciat per la temperatura, augmentant significativament quan aquesta s'incrementa. De la mateixa manera, les distàncies de dispersió també s'incrementen significativament a mesura que ho fa la temperatura. L'insecte tendeix a volar distàncies <500m (77.1% dels adults recapturats), seguint la mateixa tendència observada en laboratori. No obstant, R. ferrugineus és capaç de recórrer fins a 7km, arribant-se a registrar vols potencials en laboratori de fins a 20km. Per últim, el temps de dispersió dels adults és molt curt (>90% es recapturaren en els 7 primers die / Ávalos Masó, JA. (2015). Factors influencing the mobility of Red Palm Weevil Rhynchophorus ferrugineus (Coleoptera: Dryophthoridae) adults [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/59394 / Compendio

No description available.

There are few published direct measurements of the atmosphere-surface exchange of volatile organic compounds (VOCs), particularly for biogenic VOCs (BVOCs). Global modelling of atmospheric chemistry and transport of BVOCs has large uncertainties due to the very small number of measurements in tropical regions, which are responsible for half the global BVOC emissions. This thesis presents direct measurements of concentrations and ecosystem fluxes of BVOCs in different regions (Tropics, Mediterranean) using the approach of virtual disjunct eddy covariance (vDEC) combined with proton transfer reaction mass spectrometry (PTR-MS) – a real-time BVOC sensor. The field measurements also included methodological developments of the vDEC/PTR-MS approach, which will be of value to the wider flux measurement community. A novel approach to determining the lag time between the vertical wind measurement and the air concentration measurement has been developed that will greatly reduce the uncertainty in the derived flux measurements. In the laboratory, the selectivity of PTR-MS was investigated by designing an alternating drift-voltage mode (AD-PTR-MS) to discriminate between structural isomers detected at the same m/z channel, with monoterpenes used as model compounds. The results of the measurements, particularly from the rainforest and oil palm plantations in Borneo, are novel and therefore provide important experimental constraints on models of atmospheric emissions, chemistry and transport. For example, although parameters which work reasonably well can be derived for model algorithms for the emission of isoprene from the rainforest, their performance over oil palms was less good, because of circadian controls of emissions from oil palms. However, the larger problem is the measured basal emission rates (BERs) which are significantly smaller than those used by default in the global MEGAN model. Another novel finding was the high deposition velocities of MVK and MACR (isoprene first order oxidation products) which at the oil palm plantation commonly exceeded 1 cm s-1; this result has implications for atmospheric modelling. The successful field results relied on significant developments in software for data acquisition and processing, and operational optimisation of the PTR-MS instruments in the extreme humidity encountered during the fieldwork in Borneo.

No description available.