985 resultados para Herbivory in leaf-cutting ants
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This paper describes seagrass species and percentage cover point-based field data sets derived from georeferenced photo transects. Annually or biannually over a ten year period (2004-2015) data sets were collected using 30-50 transects, 500-800 m in length distributed across a 142 km**2 shallow, clear water seagrass habitat, the Eastern Banks, Moreton Bay, Australia. Each of the eight data sets include seagrass property information derived from approximately 3000 georeferenced, downward looking photographs captured at 2-4 m intervals along the transects. Photographs were manually interpreted to estimate seagrass species composition and percentage cover (Coral Point Count excel; CPCe). Understanding seagrass biology, ecology and dynamics for scientific and management purposes requires point-based data on species composition and cover. This data set, and the methods used to derive it are a globally unique example for seagrass ecological applications. It provides the basis for multiple further studies at this site, regional to global comparative studies, and, for the design of similar monitoring programs elsewhere.
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Spain is the fifth-largest producer of melon (Cucumis melo L.) and the second exporter in the world. To a national level, Castilla-La Mancha emphasize and, specifically, Ciudad Real, where is cultivated 27% of national area dedicated to this crop and 30% of melon national production. Melon crop is cultivating majority in Ciudad Real and it is mainly located in the Alto Guadiana, where the major aquifers of the region are located, the aquifer 23 or Mancha Occidental and the aquifer 24 or Campo de Montiel, both declared overexploited and vulnerable zones to nitrate pollution from agricultural sources. The problem is exacerbated because in this area, groundwater is the basic resource of supply to populations, and even often the only one. Given the importance of melon in the area, recent research has focused on the irrigation of melon crop. Unfortunately, scant information has been forthcoming on the effect of N fertilizer on melon piel de sapo crop, so it is very important to tackle in a serious study that lead to know the N requirements on the melon crop melon by reducing the risks of contamination by nitrate leaching without affecting productivity and crop quality. In fact, the recommended dose is often subjective and practice is a N overdose. In this situation, the taking of urgent measures to optimize the use of N fertilization is required. To do it, the effect of N in a melon crop, fertirrigated and on plastic mulch, was studied. The treatments consisted in different rates of N supply, considering N fertilizer and N content in irrigation water, so the treatment applied were: 30 (N30), 85 (N85), 112 (N112) and 139 (N139) Kg N ha-1 in 2005; 93 (N93), 243 (N243) and 393 (N393) kg ha-1 in 2006; and 11 (N11), 61 (N61), 95 (N95) and 148 (N148) kg ha-1 in 2007. A randomized complete-block design was used and each treatment was replicated four times. The results showed a significant effect of N on dry biomass and two patterns of growth were observed. On the one hand, a gradual increase in vegetative biomass of the plant, leaves and stem, with increasing N, and on the other hand, an increase of fruit biomass also with increasing N up to a maximum of biomass corresponding to the optimal dose determined in 90 kg ha-1 of N applied, corresponding to 160 kg ha-1 of N available for melon crop, since this optimum dose, the fruit biomass suffers a decline. A significant effect was observed in concentration and N uptake in leaf, steam, fruit and whole plant, increasing in all of them with increasing of N doses. Fast N uptake occurred from 30-35 to 70-80 days after transplanting, coinciding with the fruit development. The N had a clear influence on the melon yield, its components, skin thickness and flesh ratio. The melon yield increased, as the mean fruit weight and number of fruits per m2 with increasing N until achieve an above 95% of the maximum yield when the N applied is 90 kg ha-1 or 160 kg ha-1 of N available. When N exceeds the optimal amount, there is a decline in yield, reducing the mean fruit weight and number of fruits per square meter, and was also observed a decrease in fruit quality by increasing the skin thickness and decrease the flesh ratio, which means an increase in fruit hollowed with excessive N doses. There was a trend for all indexes of N use efficiency (NUE) to decline with increasing N rate. We observed two different behaviours in the calculation result of the NUE; on the one hand, all the efficiency indexes calculated with N applied and N available had an exponential trend, and on the other hand, all the efficiency indexes calculated with N uptake has a linear trend. The linear regression cuts the exponential curve, delimiting a range within which lies the optimum quantity of N. The N leaching as nitrates increased exponentially with the amount of N. The increase of N doses was affected on the N mineralization. There was a negative exponential effect of N available on the mineralization of this element that occurs in the soil during the growing season, calculated from the balances of this element. The study of N leaching for each N rate used, allowed to us to establish several environmental indices related to environmental risk that causes the use of such doses, a simple way for them to be included in the code of Best Management Practices.
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Acylamidohydrolases from higher plants have not been characterized or cloned so far. AtAMI1 is the first member of this enzyme family from a higher plant and was identified in the genome of Arabidopsis thaliana based on sequence homology with the catalytic-domain sequence of bacterial acylamidohydrolases, particularly those that exhibit indole-3-acetamide amidohydrolase activity. AtAMI1 polypeptide and mRNA are present in leaf tissues, as shown by immunoblotting and RT-PCR, respectively. AtAMI1 was expressed from its cDNA in enzymatically active form and exhibits substrate specificity for indole-3-acetamide, but also some activity against l-asparagine. The recombinant enzyme was characterized further. The results show that higher plants have acylamidohydrolases with properties similar to the enzymes of certain plant-associated bacteria such as Agrobacterium-, Pseudomonas- and Rhodococcus-species, in which these enzymes serve to synthesize the plant growth hormone, indole-3-acetic acid, utilized by the bacteria to colonize their host plants. As indole-3-acetamide is a native metabolite in Arabidopsis thaliana, it can no longer be ruled out that one pathway for the biosynthesis of indole-3-acetic acid involves indole-3-acetamide-hydrolysis by AtAMI1.
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In warm and dry climates, the use of porous systems should be required in order to allow a better leaf distribution inside the plant, causing more space in the clusters area and enhancing determined physiological processes so in the leaf (photosynthesis, v entilation, transpiration) as in berry (growth and maturation). Plant geometry indexes, yield and must composition have been studied in three different systems: sprawl with 12 shoots/m (S1); sprawl system with 18 shoots/m (S2) and vertical positioned syste m or VSP with 12 shoots/m (VSP1). Total leaf area increases as the crop load does, whoever surface area depends on to two factors: crop load and the training system (VSP vs. sprawl), which can provide differences in leaf exposure efficiencies. The main objective of this study was to validate digital photography measurements used to compare porosity differences among treatments and, as they affect plant microclimate and, therefore, yield and berry quality. Also, all previous studied indexes (LAI, SA, SFEr) tended to overestimate the relationship between exposed leaf surface and porosity of each treatment, but the use of digital method proved to be an effective tool in order to assess canopy porosity. Results showed that not positioned and free systems (sprawl) scored between 25- 50% more porosity in the clusters area than the fixed vertical system (VSP), which resulted in a better plant microclimate for test conditions, mainly by improving the exposure of internal clusters and internal canopy ventilation. On the other hand, higher crop load treatment (S2) showed a real increase in yield (16%) without any relevant change into must composition, even improving total anthocyanin content into berry during ripening
Resumo:
In warm and dry climates, the use of porous systems should be required in order to allow a better leaf distribution inside the plant, causing more space in the clusters area and enhancing determined physiological processes so in the leaf (photosynthesis, ventilation, transpiration) as in berry (growth and maturation). Plant geometry indexes, yield and must composition have been studied in three different systems: sprawl with 12 shoots/m (S1); sprawl system with 18 shoots/m (S2) and vertical positioned system or VSP with 12 shoots/m (VSP1). Total leaf area increases as the crop load does, whoever surface area depends on to two factors: crop load and the training system (VSP vs . sprawl), which can provide differences in leaf exposure efficiencies. The main objective of this study was to validate digital photography measurements used to compare porosity differences among treatments and, as they affect plant microclimate and, therefore, yield and berry quality. Also, all previous studied indexes (LAI, SA, SFEr) tended to overestimate the relationship between exposed leaf surface and porosity of each treatment, but the use of digital method proved to be an effective tool in order to assess canopy porosity. Results showed that not positioned and free systems (sprawl) scored between 25 - 50% more porosity in the clusters area than the fixed vertical system (VSP), which resulted in a better plant microclimate for test conditions, mainly by improving the exposure of internal clusters and internal canopy ventilation. On the other hand, higher crop load treatment (S2) showed a real increase in yield (16%) without any relevant change into must composition, even improving total anthocyanin content into berry during ripening
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La mejora continua de los procesos de fabricación es fundamental para alcanzar niveles óptimos de productividad, calidad y coste en la producción de componentes y productos. Para ello es necesario disponer de modelos que relacionen de forma precisa las variables que intervienen en el proceso de corte. Esta investigación tiene como objetivo determinar la influencia de la velocidad de corte y el avance en el desgaste del flanco de los insertos de carburos recubiertos GC1115 y GC2015 y en la rugosidad superficial de la pieza mecanizada de la pieza en el torneado de alta velocidad en seco del acero AISI 316L. Se utilizaron entre otros los métodos de observación científica, experimental, medición, inteligencia artificial y estadísticos. El inserto GC1115 consigue el mejor resultado de acuerdo al gráfico de medias y de las ecuaciones de regresión múltiple de desgaste del flanco para v= 350 m/min, mientras que para las restantes velocidades el inserto GC2015 consigue el mejor desempeño. El mejor comportamiento en cuanto a la rugosidad superficial de la pieza mecanizada se obtuvo con el inserto GC1115 en las velocidades de 350 m/min y 400 m/min, en la velocidad de 450 m/min el mejor resultado correspondió al inserto GC2015. Se analizaron dos criterios nuevos, el coeficiente de vida útil de la herramienta de corte en relación al volumen de metal cortado y el coeficiente de rugosidad superficial de la pieza mecanizada en relación al volumen de metal cortado. Fueron determinados los modelos de regresión múltiple que permitieron calcular el tiempo de mecanizado de los insertos sin que alcanzaran el límite del criterio de desgaste del flanco. Los modelos desarrollados fueron evaluados por sus capacidades de predicción con los valores medidos experimentalmente. ABSTRACT The continuous improvement of manufacturing processes is critical to achieving optimal levels of productivity, quality and cost in the production of components and products. This is necessary to have models that accurately relate the variables involved in the cutting process. This research aims to determine the influence of the cutting speed and feed on the flank wear of carbide inserts coated by GC1115 and GC2015 and the surface roughness of the workpiece for turning dry high speed steel AISI 316L. Among various scientific methods this study were used of observation, experiment, measurement, statistical and artificial intelligence. The GC1115 insert gets the best result according to the graph of means and multiple regression equations of flank wear for v = 350 m / min, while for the other speeds the GC2015 insert gets the best performance. Two approaches are discussed, the life ratio of the cutting tool relative to the cut volume and surface roughness coefficient in relation to the cut volume. Multiple regression models were determined to calculate the machining time of the inserts without reaching the limit of the criterion flank wear. The developed models were evaluated for their predictive capabilities with the experimentally measured values.
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El frente de un túnel puede colapsar si la presión aplicada sobre el es inferior a un valor limite denominado presión “critica” o “de colapso”. En este trabajo se desarrolla y presenta un mecanismo de rotura rotacional generado punto a punto para el cálculo de la presión de colapso del frente de túneles excavados en terrenos estratificados o en materiales que siguen un criterio de rotura nolineal. La solución propuesta es una solución de contorno superior en el marco del Análisis Límite y supone una generalización del mecanismo de rotura mas reciente existente en la bibliografía. La presencia de un terreno estratificado o con un criterio de rotura no-lineal implica una variabilidad espacial de las propiedades resistentes. Debido a esto, se generaliza el mecanismo desarrollado por Mollon et al. (2011b) para suelos, de tal forma que se puedan considerar valores locales del ángulo de rozamiento y de la cohesión. Además, la estratificación del terreno permite una rotura parcial del frente, por lo que se implementa esta posibilidad en el mecanismo, siendo la primera solución que emplea un mecanismo de rotura que se ajusta a la estratigrafía del terreno. Por otro lado, la presencia de un material con un criterio de rotura no-lineal exige introducir en el modelo, como variable de estudio, el estado tensional en el frente, el cual se somete al mismo proceso de optimización que las variables geométricas del mecanismo. Se emplea un modelo numérico 3D para validar las predicciones del mecanismo de Análisis Limite, demostrando que proporciona, con un esfuerzo computacional significativamente reducido, buenas predicciones de la presión critica, del tipo de rotura (global o parcial) en terrenos estratificados y de la geometría de fallo. El mecanismo validado se utiliza para realizar diferentes estudios paramétricos sobre la influencia de la estratigrafía en la presión de colapso. Igualmente, se emplea para elaborar cuadros de diseño de la presión de colapso para túneles ejecutados con tuneladora en macizos rocosos de mala calidad y para analizar la influencia en la estabilidad del frente del método constructivo. Asimismo, se lleva a cabo un estudio de fiabilidad de la estabilidad del frente de un túnel excavado en un macizo rocoso altamente fracturado. A partir de el se analiza como afectan las diferentes hipótesis acerca de los tipos de distribución y de las estructuras de correlación a los resultados de fiabilidad. Se investiga también la sensibilidad de los índices de fiabilidad a los cambios en las variables aleatorias, identificando las mas relevantes para el diseño. Por ultimo, se lleva a cabo un estudio experimental mediante un modelo de laboratorio a escala reducida. El modelo representa medio túnel, lo cual permite registrar el movimiento del material mediante una técnica de correlación de imágenes fotográficas. El ensayo se realiza con una arena seca y se controla por deformaciones mediante un pistón que simula el frente. Los resultados obtenidos se comparan con las estimaciones de la solución de Análisis Límite, obteniéndose un ajuste razonable, de acuerdo a la literatura, tanto en la geometría de rotura como en la presión de colapso. A tunnel face may collapse if the applied support pressure is lower than a limit value called the ‘critical’ or ‘collapse’ pressure. In this work, an advanced rotational failure mechanism generated ‘‘point-by-point” is developed to compute the collapse pressure for tunnel faces in layered (or stratified) grounds or in materials that follow a non-linear failure criterion. The proposed solution is an upper bound solution in the framework of limit analysis which extends the most advanced face failure mechanism in the literature. The excavation of the tunnel in a layered ground or in materials with a non-linear failure criterion may lead to a spatial variability of the strength properties. Because of this, the rotational mechanism recently proposed by Mollon et al. (2011b) for Mohr-Coulomb soils is generalized so that it can consider local values of the friction angle and of the cohesion. For layered soils, the mechanism needs to be extended to consider the possibility for partial collapse. The proposed methodology is the first solution with a partial collapse mechanism that can fit to the stratification. Similarly, the use of a nonlinear failure criterion introduces the need to introduce new parameters in the optimization problem to consider the distribution of normal stresses along the failure surface. A 3D numerical model is employed to validate the predictions of the limit analysis mechanism, demonstrating that it provides, with a significantly reduced computational effort, good predictions of critical pressure, of the type of collapse (global or partial) in layered soils, and of its geometry. The mechanism is then employed to conduct parametric studies of the influence of several geometrical and mechanical parameters on face stability of tunnels in layered soils. Similarly, the methodology has been further employed to develop simple design charts that provide the face collapse pressure of tunnels driven by TBM in low quality rock masses and to study the influence of the construction method. Finally, a reliability analysis of the stability of a tunnel face driven in a highly fractured rock mass is performed. The objective is to analyze how different assumptions about distributions types and correlation structures affect the reliability results. In addition, the sensitivity of the reliability index to changes in the random variables is studied, identifying the most relevant variables for engineering design. Finally, an experimental study is carried out using a small-scale laboratory model. The problem is modeled in half, cutting through the tunnel axis vertically, so that displacements of soil particles can be recorded by a digital image correlation technique. The tests were performed with dry sand and displacements are controlled by a piston that supports the soil. The results of the model are compared with the predictions of the Limit Analysis mechanism. A reasonable agreement, according to literature, is obtained between the shapes of the failure surfaces and between the collapse pressures observed in the model tests and computed with the analytical solution.
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En regiones semiáridas, con veranos cálidos, evapotranspiraciones elevadas, humedades relativas bajas, además de precipitaciones intermitentes y escasas (400 mm al año) que reducen la recarga del perfil en invierno, se puede ver afectada la productividad y sostenibilidad de los viñedos. Por eso en estas zonas puede ser necesario utilizar el riego suplementario para mantener la calidad y aumentar la productividad. En este marco de circunstancias es en el que se desarrolla la mayoría de la viticultura española, y en concreto en la zona centro donde se realizó el estudio. Con este trabajo se pretende estudiar la influencia del agua del riego, con distintas dosis y aplicada en diferentes fases de crecimiento y maduración de la baya, en la producción y calidad de la uva. Se estudió la influencia del déficit moderado continuo aplicado antes y después de envero, en el aprovechamiento de los recursos ambientales y en la respuesta del cv. Cabernet Sauvignon. El ensayo se desarrolló en 2010 y 2011 en la finca “La Alcoholera”, perteneciente a bodegas LICINIA S.L., ubicada en la localidad de Chinchón, Comunidad de Madrid, España. Durante 2010 y 2011 se realizaron estudios en cepas del cv. Cabernet Sauvignon (clon 15), injertadas sobre 41B y plantadas en 2005. Con poda corta en Cordón Royat unilateral de 80 cm de altura, y cuya vegetación alcanzó una altura de 97 cm. Las cepas del ensayo fueron conducidas verticalmente en espaldera (VSP), con 10 yemas por metro lineal. Las plantas dentro de la fila fueron separadas 1 m y la distancia de la calle fue de 3 m. La orientación de las filas norte – sur. Se plantearon cuatro tratamientos experimentales con diferentes dosis y momento de aplicación del riego. - T: Testigo. Déficit ligero, con un aporte continuado de agua desde floración (420 mm). - DMc: Déficit moderado continuo. Manejo del riego convencional, empezando en pre-envero (154 mm) - DM1: Déficit moderado a partir de pre-envero. Aporte de riego continuado desde floración reduciéndose la dosis de riego en pre-envero (312 mm). - DM2: Déficit moderado hasta pre-envero. Se empezó a regar a partir de preenvero (230 mm). Se observó que bajo condiciones de estrés hídrico leve, el crecimiento se reduce disminuyendo la migración de fotoasimilados hacia los órganos vegetativos. Generando menor área foliar en las plantas sometidas a déficit hídrico moderado entre floración y cuajado. Disminuyendo su consumo. En maduración la humedad del suelo dependió principalmente del riego aplicado y del consumo de la planta; dicho consumo dependió a la vez del desarrollo foliar del canopy y de la necesidad hídrica de la vid. El aumento del déficit hídrico disminuyó el contenido de agua en el suelo, lo que provocó diferencias en el estado hídrico y en el intercambio gaseoso de las hojas. En condiciones de déficit moderado, la fotosíntesis se encontró altamente correlacionada con el potencial hídrico foliar medido a mediodía solar. Además en condiciones de déficit moderado continuo la disponibilidad hídrica, la demanda atmosférica y el nivel de hidratación de las hojas, interaccionaron de forma compleja en la regulación estomática de las hojas, condicionando el intercambio gaseoso y la eficiencia en el uso del agua. Al aumentar el volumen de agua aplicado el peso de madera de poda por metro de fila fue superior. Las diferencias encontradas en el rendimiento fueron debidas a las diferencias en el peso de baya. El cual estuvo condicionado por la estrategia de riego, ya que, el déficit hídrico moderado antes de envero fue más crítico para el rendimiento que el déficit impuesto durante la madurez. Por otro lado, la biomasa dependió de la actividad fisiológica de la planta, la cual fue altamente dependiente de la disponibilidad hídrica. Déficit hídrico moderado aplicado de cuajado a envero, generó bayas más pequeñas y aumentó la relación hollejo:pulpa. El déficit moderado aplicado después de envero favoreció la acumulación de IPT y antocianos extraíbles, mejorando la calidad de la uva, pero disminuyó la acidez de la baya. El riego aplicado de envero a vendimia desaceleró la concentración de azúcares en bayas que fueron sometidas a déficit antes de pre-envero. ABSTRACT Mediterranean climate is characterized by hot summers, high evapotranspiration rates, and scarce precipitations (400 mm per year) during grapevine cycle. These extremely dry conditions affect vineyard productivity and sustainability. Supplementary irrigation is needed practice in order to maintain yield and quality. Almost all Spanish grape growing regions are characterized by these conditions, especially in the center region, where this trial was performed. The main objective of this work is to study the influence of water irrigation on yield and quality. For this aim, different levels of irrigation (mm of water applied) were applied during different stages of growth and berry maturity of Caberent Sauvignon grapevines. The work was conducted from 2010 to 2011 and located in Licinia (40º 12´ N, 3º 28´ W), Madrid, Spain. The cultivar utilized was Cabernet Sauvignon, clone 15 grafted onto rootstock 41B, planted in 2005. The vineyard was oriented north-south, with spacing on 3 meters between rows and 1 meter between plants. Vines were spurpruned to 10 buds per meter and trained in unilateral cordon with a height of 80 cm. Shoots were positioned vertically (VSP). Considering the amount of water and the moment of the application, four experimental treatments were applied: - T: Control sample. Slight deficit (420 mm) applied from bloom to maturity. - DMc: Continuous moderate deficit. Traditional irrigation: application of 154 mm of water from pre-veraison to maturity. - DM1: Deficit moderate from pre-veraison. Irrigation of 312 mm of water from bloom to pre-veraison. - DM2: Deficit moderate to pre-veraison. Irrigation of 230 mm of water from preveraison to maturity Under moderated water stress conditions it was seen than leaf growth decreases due to the reduction of migration of photo-assimilates to vegetative organs. Vines with moderate water deficit between flowering and ripening develop less leaf area and decrease its water consumption. During maturation of berries, soil moisture depends on irrigation and plant consumption. This consumption further depends on vegetation development and on the vine needs for water. By increasing water deficit, the water content in the soil decreases. This causes differences in leaf water status and in the gases exchange. Under moderate deficit conditions, photosynthesis was found highly correlated with midday leaf water potential. Further, atmospheric demand and the level of leaves hydration interact in complex ways in the stomatal regulation, which affects leaf gas exchange and the efficiency of water use. The amount of water applied is directly proportional to pruning weight. Changes in berry weight cause differences in yield ratios. The differences in berry weights are conditioned by the irrigation strategy, the moderate water deficit before veraison influences more than the deficit applied from veraison. Biomass generated for the plant depends on its physiological activity, which is highly related to the water availability. Moderate water deficit applied from fruit set to ripening generates smaller berries, increasing the pulp/skin ratio. Moderate deficit applied after veraison promotes the accumulation of extractables anthocyans and TPI. Despite this treatment improves color parameters of the grapes, it decreases its total acidity. Irrigation applied from veraison to harvest slows down sugar accumulation in berries compared to those under deficit before veraison conditions.
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El objetivo principal de esta tesis doctoral es profundizar en el análisis y diseño de un sistema inteligente para la predicción y control del acabado superficial en un proceso de fresado a alta velocidad, basado fundamentalmente en clasificadores Bayesianos, con el prop´osito de desarrollar una metodolog´ıa que facilite el diseño de este tipo de sistemas. El sistema, cuyo propósito es posibilitar la predicción y control de la rugosidad superficial, se compone de un modelo aprendido a partir de datos experimentales con redes Bayesianas, que ayudar´a a comprender los procesos dinámicos involucrados en el mecanizado y las interacciones entre las variables relevantes. Dado que las redes neuronales artificiales son modelos ampliamente utilizados en procesos de corte de materiales, también se incluye un modelo para fresado usándolas, donde se introdujo la geometría y la dureza del material como variables novedosas hasta ahora no estudiadas en este contexto. Por lo tanto, una importante contribución en esta tesis son estos dos modelos para la predicción de la rugosidad superficial, que se comparan con respecto a diferentes aspectos: la influencia de las nuevas variables, los indicadores de evaluación del desempeño, interpretabilidad. Uno de los principales problemas en la modelización con clasificadores Bayesianos es la comprensión de las enormes tablas de probabilidad a posteriori producidas. Introducimos un m´etodo de explicación que genera un conjunto de reglas obtenidas de árboles de decisión. Estos árboles son inducidos a partir de un conjunto de datos simulados generados de las probabilidades a posteriori de la variable clase, calculadas con la red Bayesiana aprendida a partir de un conjunto de datos de entrenamiento. Por último, contribuimos en el campo multiobjetivo en el caso de que algunos de los objetivos no se puedan cuantificar en números reales, sino como funciones en intervalo de valores. Esto ocurre a menudo en aplicaciones de aprendizaje automático, especialmente las basadas en clasificación supervisada. En concreto, se extienden las ideas de dominancia y frontera de Pareto a esta situación. Su aplicación a los estudios de predicción de la rugosidad superficial en el caso de maximizar al mismo tiempo la sensibilidad y la especificidad del clasificador inducido de la red Bayesiana, y no solo maximizar la tasa de clasificación correcta. Los intervalos de estos dos objetivos provienen de un m´etodo de estimación honesta de ambos objetivos, como e.g. validación cruzada en k rodajas o bootstrap.---ABSTRACT---The main objective of this PhD Thesis is to go more deeply into the analysis and design of an intelligent system for surface roughness prediction and control in the end-milling machining process, based fundamentally on Bayesian network classifiers, with the aim of developing a methodology that makes easier the design of this type of systems. The system, whose purpose is to make possible the surface roughness prediction and control, consists of a model learnt from experimental data with the aid of Bayesian networks, that will help to understand the dynamic processes involved in the machining and the interactions among the relevant variables. Since artificial neural networks are models widely used in material cutting proceses, we include also an end-milling model using them, where the geometry and hardness of the piecework are introduced as novel variables not studied so far within this context. Thus, an important contribution in this thesis is these two models for surface roughness prediction, that are then compared with respecto to different aspects: influence of the new variables, performance evaluation metrics, interpretability. One of the main problems with Bayesian classifier-based modelling is the understanding of the enormous posterior probabilitiy tables produced. We introduce an explanation method that generates a set of rules obtained from decision trees. Such trees are induced from a simulated data set generated from the posterior probabilities of the class variable, calculated with the Bayesian network learned from a training data set. Finally, we contribute in the multi-objective field in the case that some of the objectives cannot be quantified as real numbers but as interval-valued functions. This often occurs in machine learning applications, especially those based on supervised classification. Specifically, the dominance and Pareto front ideas are extended to this setting. Its application to the surface roughness prediction studies the case of maximizing simultaneously the sensitivity and specificity of the induced Bayesian network classifier, rather than only maximizing the correct classification rate. Intervals in these two objectives come from a honest estimation method of both objectives, like e.g. k-fold cross-validation or bootstrap.
Resumo:
La disponibilidad hídrica es uno de los principales factores que determinan el rendimiento del viñedo en muchas regiones vitícolas, por lo que sus consecuencias han sido ampliamente estudiadas. Sin embargo, para una cantidad de agua de riego determinada, otros aspectos como la frecuencia de aplicación, o la combinación entre el caudal de los goteros y la distancia entre los mismos (es decir, el patrón de distribución de agua en el suelo), pueden jugar un papel relevante, pero estos factores han sido poco estudiados. El objetivo de este trabajo ha sido evaluar las implicaciones agronómicas y fisiológicas de dos frecuencias de riego (IrrF, cada 2 y 4 días) y dos patrones de distribución de agua (DisP, goteros de 2 L h-1 separados 0,6 m vs. goteros de 4 L h-1 separados 1,2 m). El experimento se llevó a cabo durante cuatro temporadas consecutivas en un viñedo cv. Syrah con un suelo arcilloso en el centro de España, y los dos factores fueron evaluados bajo dos condiciones de disponibilidad hídrica (Baja: 20% de ETo y Media: 40% de ETo). El efecto de la frecuencia de riego y el patrón de distribución de agua en la respuesta agronómica del cv. Syrah se ha estudiado en el capítulo 1. La frecuencia de riego y el patrón de distribución de agua en el suelo afectaron a algunos aspectos de los componentes de rendimiento y desarrollo vegetativo en las dos condiciones de disponibilidad hídrica, aunque los efectos observados no fueron los mismos todos los años. Los efectos fueron más evidentes para IrrF en condiciones de baja disponibilidad hídrica y para DisP en condiciones de disponibilidad hídrica media. Dos de los cuatro años del experimento, el pasar de frecuencia de riego de 2 días a 4 días causó un incremento medio de rendimiento del 20% para la situación de baja disponibilidad hídrica. La textura del suelo, sin duda ha condicionado los resultados obtenidos en los tratamientos regados con el 20% de la ETo, ya que regar cada dos días implicaba la aplicación de pequeñas cantidades de agua y se formaban bulbos de riego superficiales, probablemente favoreciendo las pérdidas por evaporación. En el capítulo 2, se ha analizado el efecto de la frecuencia de riego y del patrón de distribución de agua en el estado hídrico de la planta y el intercambio gaseoso a nivel de hoja con el fin de explicar las diferencias observadas en la respuesta agronómica. En lo que respecta a la frecuencia de riego, en condiciones de baja disponibilidad hídrica, las plantas regadas cada 4 días (plantas 4d), mostraron mayores tasas de asimilación neta y conductancia estomática que las plantas regadas cada 2 días (plantas 2d), lo que es consistente con la hipótesis de que con la frecuencia de riego de 2 días se produjo una pérdida de eficiencia del uso del agua, probablemente debido a una mayor evaporación como consecuencia del hecho de que el volumen de suelo mojado creado era pequeño y cerca de la superficie. En condiciones de disponibilidad hídrica media, las diferencias en el intercambio gaseoso a nivel de hoja fueron mucho más pequeñas. Al comienzo del verano cada frecuencia de riego se comportó mejor uno de los días de medida, compensando al final del ciclo de riego de 4 días. Sin embargo, a medida que avanzó el verano y el déficit de agua se hizo más alto, las diferencias significativas aparecieron sólo en el 'día 4' del ciclo de riego, cuando las plantas 2d se comportaron mejor que las plantas regadas 4d que llevaban tres días sin regarse. Estas diferencias fisiológicas fueron menores que en condiciones de baja disponibilidad hídrica y al parecer no suficientes para afectar el comportamiento agronómico. En cuanto al patrón de distribución de agua, el efecto fue poco significativo, pero la mayor densidad de goteros tendió a presentar un mayor intercambio gaseoso a nivel de hoja, especialmente a media mañana. El efecto fue más importante para las condiciones de disponibilidad hídrica media. En el capítulo 3, se han comparado las relaciones entre el intercambio gaseoso a nivel de hoja, el estado hídrico y la demanda atmosférica, con el fin de explicar los cambios en la intensidad de la respuesta fisiológica observados en el Capítulo 2. No se han encontrado diferencias en dichas relaciones para el patrón de distribución de agua, por lo que sólo se ha analizado el efecto de la frecuencia de riego. El estudio se ha centrado fundamentalmente en si las plantas mostraron una respuesta fisiológica diferente a los cambios en el estado hídrico y en la demanda atmosférica según el tiempo transcurrido desde el último riego. Las diferencias observadas explican los resultados obtenidos en los capítulos anteriores, y sugieren la existencia de procesos de aclimatación vinculados a la frecuencia de riego y a la disponibilidad hídrica. Las plantas bajo condiciones de baja disponibilidad hídrica se mostraron más aclimatadas al estrés hídrico que aquellas en condiciones de disponibilidad hídrica media. La frecuencia de riego afectó claramente la relación entre los parámetros de intercambio gaseoso a nivel de hoja, el estado hídrico de la planta y las condiciones atmosféricas, y junto con la cantidad de agua aplicada tuvo implicaciones en el desarrollo de mecanismos de aclimatación que afectaron a la respuesta fisiológica de la planta, afectando a la eficiencia del riego. ABSTRACT Water availability is one of the major factors that determine vineyard performance in many grape growing regions, so its implications have been widely studied before. However, for a given irrigation water amount, other aspects such as application frequency, or emitter spacing and flow rate (i.e., distribution pattern), may play a relevant role, but these factors have been scarcely studied. The aim of this work was to evaluate the agronomic and physiological implications of two irrigation frequencies (IrrF, every 2 and 4 days) and two water distribution patterns (DisP, 2 L h−1 emitters every 0.6 m vs. 4 L h−1 emitters every 1.2 m). The experiment was carried out during four consecutive seasons in a cv. Syrah vineyard with a clay soil in central Spain, and the two factors were evaluated under two water availability conditions (LOW WA: 20% of ETo and MEDIUM WA: 40% of ETo). The effect of irrigation frequency and water distribution pattern on the agronomical response of cv. Syrah was studied in Chapter 1. IrrF and DisP affected some aspects of vegetative development and yield components under both water availability conditions, although the effects observed were not the same every year. The effects were more evident for IrrF under low water availability and for DisP under medium water availability. Two out of the four years of the experiment, the change of irrigation frequency from 2 days to 4 days promoted an average yield increase of 20% for the LOW WA situation. Soil texture certainly conditioned the results obtained under LOW WA conditions, since high frequency irrigation implied applying small amounts of water that resulted in limited superficial water bulbs, which probably favored water evaporation. In Chapter 2, the effect of irrigation frequency and water distribution pattern on plant water status and leaf gas exchange was analyzed to explain the differences observed in the agronomical response. Concerning irrigation frequency, under LOW WA conditions, applying irrigation every 4 days, resulted in higher net assimilation rates and stomatal conductance than doing it every 2 days, supporting the hypothesis that the latter frequency resulted in a water use efficiency loss, probably due to higher evaporation as a consequence of the fact the wetted soil volume created was small and close to the surface. Under MEDIUM WA conditions, differences in leaf gas exchange were much smaller. At the beginning of the summer each irrigation frequency behaved better one of the measurements days, compensating at the end of the 4-day irrigation cycle. However, as the summer progressed and water deficit became higher, significant differences appeared only on ‘day 4’ of the irrigation cycle, when 2d plants behaved better than 4d plants. These physiological differences were smaller than under LOW WA conditions and apparently not sufficient to affect agronomical performance. Regarding water distribution pattern, the effect was less significant but the closest emitter spacing resulted in general terms in a higher leaf gas exchange, especially at midmorning. The effect was more noticeable for MEDIUM WA conditions. In Chapter 3, the relationships between leaf gas exchange and leaf water status and atmospheric demand were compared to explain the changes in the intensity of the physiological response observed in Chapter 2. No differences were found in the relationships for water distribution pattern, so only the effect of irrigation frequency was analyzed focusing on whether the plants have a different physiological response to changes in water status and atmospheric demand according to the time elapsed since the last irrigation. Differences observed in the relationships explained the results obtained in the previous chapters, and point at the occurrence of acclimation processes linked to irrigation frequency and to water availability. Plants under LOW WATER AVAILABILITY conditions seemed to be more acclimated to water stress than those under MEDIUM WATER AVAILABILITY conditions. Irrigation frequency clearly affected the relationship between leaf gas exchange parameters, plant water status and atmospheric conditions, and together with the amount of water applied had implications in the development of acclimation mechanisms that affected plant physiological response, thus affecting irrigation efficiency.
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To understand how sucrose (Suc) is transported from source leaves to developing tap roots of carrot (Daucus carota L.), we cloned two cDNAs (DcSUT1 and DcSUT2) for proteins with homologies to plant Suc/H+ symporters. The deduced polypeptide sequences are 52% identical and have 12 predicted membrane-spanning domains each. Transport activities were confirmed by expression of the clones in yeast cells. Both transporters had optimal activity below pH 5.0 and Michaelis constant values of 0.5 mm. Suc uptake was inhibited by protonophores, suggesting that Suc transport is linked to the proton electrochemical potential across the plasma membrane. DcSUT1 and DcSUT2 had markedly different expression patterns. Transcripts of DcSUT1 were found only in the green parts of plants, with highest levels in the lamina of source leaves, indicating that DcSUT1 is required for the loading of Suc into the phloem. In leaf lamina expression was diurnally regulated, suggesting that Suc export from the leaves is higher during the day than during the night. The mRNA of DcSUT2 was found mainly in sink organs, and no diurnal expression pattern was detected in the storage root. Here, expression was not restricted to the phloem but was much higher in storage parenchyma tissues of phloem and xylem. The close relationship of DcSUT2 with a Suc/H+ symporter from fava bean, which facilitates Suc uptake into the cotyledons of developing seeds, indicates that this carrot Suc transporter may be involved in loading Suc into storage parenchyma cells.
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We isolated and characterized a novel light-regulated cDNA from the short-day plant Pharbitis nil that encodes a protein with a leucine (Leu) zipper motif, designated PNZIP (Pharbitis nil Leu zipper). The PNZIP cDNA is not similar to any other gene with a known function in the database, but it shares high sequence homology with an Arabidopsis expressed sequence tag and to two other sequences of unknown function from the cyanobacterium Synechocystis spp. and the red alga Porphyra purpurea, which together define a new family of evolutionarily conserved Leu zipper proteins. PNZIP is a single-copy gene that is expressed specifically in leaf photosynthetically active mesophyll cells but not in other nonphotosynthetic tissues such as the epidermis, trichomes, and vascular tissues. When plants were exposed to continuous darkness, PNZIP exhibited a rhythmic pattern of mRNA accumulation with a circadian periodicity of approximately 24 h, suggesting that its expression is under the control of an endogenous clock. However, the expression of PNZIP was unusual in that darkness rather than light promoted its mRNA accumulation. Accumulation of PNZIP mRNA during the dark is also regulated by phytochrome, since a brief exposure to red light in the middle of the night reduced its mRNA levels. Moreover, a far-red-light treatment at the end of day also reduced PNZIP mRNA accumulation during the dark, and that effect could be inhibited by a subsequent exposure to red light, showing the photoreversible response attributable to control through the phytochrome system.
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A number of aberrant morphological phenotypes were noted during propagation of the Arabidopsis thaliana DNA hypomethylation mutant, ddm1, by repeated self-pollination. Onset of a spectrum of morphological abnormalities, including defects in leaf structure, flowering time, and flower structure, was strictly associated with the ddm1 mutations. The morphological phenotypes arose at a high frequency in selfed ddm1 mutant lines and some phenotypes became progressively more severe in advancing generations. The transmission of two common morphological trait syndromes in genetic crosses demonstrated that the phenotypes are caused by heritable lesions that develop in ddm1 mutant backgrounds. Loss of cytosine methylation in specific genomic sequences during the selfing regime was noted in the ddm1 mutants. Potential mechanisms for formation of the lesions underlying the morphological abnormalities are discussed.
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Na atual conjuntura, no que se refere à energia renovável, o etanol é um dos principais, se não o mais importante, produto brasileiro. Proveniente da fermentação de açúcares, processo conhecido há séculos, tem se tornado o carro chefe do país como garantia de voz ativa nas discussões energéticas pelo mundo afora. Porém, atualmente, o setor sucroalcooleiro está passando por um momento de cautela devido à queda de produtividade e longevidade dos canaviais ao longo dos últimos anos ocasionados principalmente pela mecanização da colheita e plantio da cana-de-açúcar. Cabe ressaltar que as perdas de produção podem ser ainda maiores diante da ausência do manejo varietal e de cuidados adequados em relação à sanidade de mudas utilizadas para a multiplicação de viveiros. Nesse sentido, nos últimos anos, o emprego da irrigação no cultivo da cana-de-açúcar associada a outras tecnologias de plantio, tais como formação de viveiros com mudas pré-brotadas, vem merecendo papel de destaque. Esse cenário obriga pesquisadores a buscar novas tecnologias para aumento de produtividade, longevidade dos canaviais e redução do custo por tonelada de cana produzida, tais como a produção de mudas sadias para formação de viveiros de cana-de-açúcar. Diante disso, a presente pesquisa teve por objetivo, submeter mudas pré-brotadas de cana-de-açúcar, durante plantio de inverno, na região de Piracicaba, SP, sob diferentes lâminas de irrigação (10 mm; 20 mm; 30 mm e 40 mm), utilizando um sistema de irrigação por aspersão com alas móveis. Dessa forma, buscou-se determinar qual seria a melhor lâmina de irrigação, necessária para garantir o melhor índice de pegamento e alto vigor no estabelecimento e desenvolvimento das mudas pré-brotadas de cana-de-açúcar para a região de Piracicaba-SP. Foram feitas avaliações periódicas (não destrutivas), tais como: mortalidade das mudas; clorofila total na folha; tamanho da muda; índice de área foliar; número de perfilhos brotados por metro; percentual de falha no canavial. Além de avaliações periódicas (destrutivas), tais como: avaliação do tamanho da raiz; massa seca da raiz; massa seca da parte aérea e número de perfilhos totais. As análises estatísticas das lâminas de irrigação foram realizadas pelo método de Tukey ao nível de 5% de probabilidade. Diante dos resultados obtidos, verificou-se que a lâmina de 10 mm possibilitou os melhores índices de pegamento e proporcionou um índice superior a 97,8% de sobrevivência de mudas. Também, observou-se uma estreita relação entre o índice de mortalidade no plantio de inverno das mudas pré-brotadas de cana-de-açúcar com o manejo da irrigação, a qual nos primeiros dias após plantio foi fundamental para o estabelecimento e desenvolvimento das mudas. Cabe ressaltar que em caso da adoção de outro manejo de irrigação, com lâminas maiores, nessas condições experimentais, possivelmente haveria perdas de água, cujo fato nos dias atuais não é o ideal tendo em vista a busca por economia e manejo racional da água.
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O desenvolvimento de algoritmos computacionais para a obtenção de distribuições de tamanho de partícula em dispersões e que utilizam dados espectroscópicos em tempo real e in-line a partir de sensores permitirá uma variedade de aplicações, como o monitoramento de propriedades em fluidos de corte industriais, acompanhamento de processos de polimerização, tratamento de efluentes e sensoriamento atmosférico. O presente estudo tem como objetivo a implementação e comparação de técnicas para resolução de problemas de inversão, desenvolvendo algoritmos que forneçam distribuição de tamanho de partículas em dispersões a partir de dados de espectroscopia UV-Vis-Nir (Ultravioleta, Visível e Infravermelho próximo). Foram implementadas quatro técnicas, sendo uma delas um método alternativo sem a presença de etapas de inversão. Os métodos que utilizaram alguma técnica de inversão evidenciaram a dificuldade em se obter distribuições de tamanho de gotas (DTG) de boa qualidade, enquanto o método alternativo foi aquele que se mostrou mais eficiente e confiável. Este estudo é parte de um programa cooperativo entre a Universidade de São Paulo e a Universidade de Bremen chamado programa BRAGECRIM (Brazilian German Cooperative Research Initiative in Manufacturing) e é financiado pela FAPESP, CAPES, FINEP e CNPq (Brasil) e DFG (Alemanha).