2,133 research outputs found

    Towards the Integrated Management of the Texas Citrus Mite Eutetranychus Banksi (Acari: Tetranychidae) in Spain

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    [ES] El ácaro de Texas, Eutetranychus banksi McGregor, es nativo de América y está ampliamente distribuido por el cultivo de cítricos de este continente. En 2013, esta especie se detectó en el sur de la provincia de Valencia, afectando a la principal zona citrícola de España. El ácaro produce graves daños reduciendo la fotosíntesis, causando defoliación y decoloración de los frutos, lo que podría afectar a su valor económico. En primer lugar, este trabajo evaluó el impacto ecológico producido por la especie invasora sobre las especies de ácaros tetraníquidos residentes en los cítricos valencianos Panonychus citri (McGregor) y Eutetranychus orientalis (Klein). Desde su llegada en 2013, E. banksi se ha convertido en el tetraníquido más frecuente y abundante en cítricos desplazando competitivamente a las otras especies, reduciendo su presencia y distribución geográfica, a su vez influenciada por su historia de colonización. En segundo lugar, este trabajo estudió la distribución dentro del árbol y las tendencias estacionales de la plaga y de los ácaros fitoseidos asociados, que pueden contribuir a su control. El ácaro de Texas se alimentó principalmente en la cara adaxial (haz) de las hojas en la periferia de la copa del árbol, mostrando un único pico de población a finales de verano-principios de otoño, mientras que los fitoseidos prefirieron la cara abaxial (envés) de las hojas del interior de la copa, mostrando dos picos, uno principal en primavera y otro menos abundante en otoño. Euseius stipulatus (Athias-Henriot) fue el fitoseido más frecuente y abundante, y cuando E. banksi aumentó se desplazó a las caras adaxiales de las hojas de la parte exterior de la copa y los frutos para alimentarse de su presa, cambiando su coloración de blanco a marrón rojizo evidenciando su contribución al control biológico de la plaga. Sin embargo, no fue capaz de mantener las poblaciones de E. banksi bajo densidades tolerables debido a la desfavorable relación depredador/presa que existe en verano y principios de otoño. En tercer lugar, este trabajo pretendió describir la estructura de población del ácaro de Texas y definir un plan de muestreo. Existieron diferencias en la estructura de edad en frutos y hojas, así como entre hojas de diferentes brotes. Además, a lo largo del tiempo se observaron fluctuaciones en su composición correlacionadas con variaciones en la proporción de sexos. No se observaron diferencias de agregación entre estratos vegetales, pero sí entre estadios inmaduros y adultos, siendo las hembras las menos agregadas. La alta correlación de la población total con las formas móviles y las hembras permitió utilizar ambas como estadio de referencia para el desarrollo del plan de muestreo, estableciendo un muestreo de presencia/ausencia de 100 hojas para las hembras o 400 hojas para las formas móviles. Finalmente, un ácaro fitoseido recientemente descrito, Neoseiulus madeirensis Papadoulis & Kapaxidi, se encontró asociado a E. banksi, sugiriendo que podría ser un candidato prometedor para su control biológico. En cuarto lugar, este trabajo pretendió evaluar el potencial de este depredador para controlar las poblaciones de la plaga. Neoseiulus madeirensis mostró un rápido desarrollo y altas tasas de supervivencia y reproducción alimentándose de E. banksi. El depredador se alimentó principalmente de estadios inmaduros, siendo los huevos el estadio preferido, y mostrando una respuesta funcional de tipo II para todos los estadios de presa ensayados, que se estabilizó a altas densidades de presa con una elevada puesta de huevos. Los valores de supervivencia, reproducción y depredación han sido los mejores obtenidos hasta el momento para cualquier fitoseido ensayado previamente contra E. banksi, lo convierte en un candidato idóneo para el desarrollo de un programa de control biológico basado en sueltas aumentativas, o en la importación con vistas al establecimiento de poblaciones permanentes en cítricos.[CA] L'àcar de Texas, Eutetranychus banksi McGregor, és nadiu d' Amèrica i està àmpliament distribuït pel cultiu de cítrics d'aquest continent. El 2013, esta espècie es va detectar al sud de la província de València, afectant la principal zona citrícola d'Espanya. L'àcar produeix greus danys reduint la fotosíntesi, causant defoliació i decoloració dels fruits, cosa que podria afectar el seu valor econòmic. En primer lloc, aquest treball va avaluar l'impacte ecològic produït per l'espècie invasora sobre les espècies d'àcars tetraníquids residents als cítrics valencians Panonychus citri (McGregor) i Eutetranychus orientalis (Klein). Des de la seva arribada el 2013, E. banksi s'ha convertit en el tetraníquid més freqüent i abundant en cítrics desplaçant competitivament les altres espècies, reduint la seva presència i distribució geogràfica, alhora influenciat per la seva història de colonització. En segon lloc, aquest treball va estudiar la distribució dins de l'arbre i les tendències estacionals de la plaga i dels àcars fitoseids associats, que poden contribuir al seu control. L'àcar de Texas es va alimentar principalment en la cara adaxial (fes) de les fulles a la perifèria de la copa de l'arbre, mostrant un únic pic de població a finals d'estiu-principis de tardor, mentre que els fitoseids van preferir la cara abaxial (revers) de les fulles de l'interior de la copa, mostrant dos pics, un de principal a la primavera i un altre menys abundant a la tardor. Euseius stipulatus (Athias-Henriot) va ser el fitoseid més freqüent i abundant, i quan E. banksi va augmentar es va desplaçar a les cares adaxials de les fulles de la part exterior de la copa i els fruits per alimentar-se de la presa, canviant la seva coloració de blanc a marró vermellós evidenciant la seva contribució al control biològic de la plaga. Tot i això, no va ser capaç de mantenir les poblacions d'E. banksi sota densitats tolerables a causa de la desfavorable relació depredador/presa que hi ha a l'estiu i principis de tardor. En tercer lloc, aquest treball va voler descriure l'estructura de població de l'àcar de Texas i definir un pla de mostreig. Hi hagué diferències en l'estructura d'edat de fruits i fulles, així com entre fulles de diferents brots. A més, al llarg del temps es van observar fluctuacions en la composició correlacionades amb variacions en la proporció de sexes. No es van observar diferències d'agregació entre estrats vegetals, però sí entre estadis immadurs i adults, sent les femelles les menys agregades. L'alta correlació de la població total amb les formes mòbils i les femelles va permetre utilitzar totes dues com a estadi de referència per al desenvolupament del pla de mostreig, establint un mostreig de presència/absència de 100 fulls per a les femelles o 400 fulls per a les formes mòbils. Finalment, una espècie fitoseid recentment descrit, Neoseiulus madeirensis Papadoulis & Kapaxidi, es va trobar associat a E. banksi, suggerint que podria ser un candidat prometedor per al seu control biològic. En quart lloc, aquest treball va voler avaluar el potencial d'aquest depredador per controlar les poblacions de la plaga. Neoseiulus madeirensis va mostrar un desenvolupament ràpid i altes taxes de supervivència i reproducció alimentant-se d'E. banksi. El depredador es va alimentar principalment d'estadis immadurs, sent els ous l'estadi preferit, i mostrant una resposta funcional de tipus II per a tots els estadis de presa assajats, que es va estabilitzar a altes densitats de presa amb una posta d'ous elevada. Els valors de supervivencia, depredació i reproducció han estat els millors obtinguts fins ara per a qualsevol espècie de fitoseid assajat prèviament contra E. banksi, cosa que el converteix en un candidat idoni per al desenvolupament d'un programa de control biològic basat en soltes augmentatives, o en la importació amb vista a l'establiment de poblacions permanents en cítrics.[EN] The Texas citrus mite, Eutetranychus banksi McGregor, is native to the Americas and widely distributed across this continent. In 2013 it was detected in the south of the province of Valencia, affecting the main citrus-growing area in Spain. The mite produces severe damage, reducing photosynthesis, causing defoliation, and producing a lack in fruit pigmentation, which could affect its economic value. Firstly, this work evaluated the ecological impact produced by the invasive species on the resident spider mites Panonychus citri (McGregor) and Eutetranychus orientalis (Klein). Since its arrival in 2013, E. banksi has become the most frequent and abundant spider mite on citrus, competitively displacing the other species and reducing their presence and geographic range, which is influenced by its colonisation history. Secondly, this work studies the within-tree distribution and seasonal trends of the pest and associated phytoseiid mites, which may contribute to its control. The Texas citrus mite was feeding mainly on the adaxial (upper) side of leaves in the periphery of the tree canopy showing a single population peak in late summer-early autumn, while phytoseiids preferred the abaxial (lower) sides inside the canopy showing two peaks, a main spring peak and a second, less abundant, in autumn. Euseius stipulatus (Athias-Henriot) was the most frequent and abundant phytoseiid, and when E. banksi increased, it moved to the adaxial sides on outer leaves and fruits to feed on its prey and changed its colouring from white to reddish-brown, evidencing its contribution to biological pest control. However, it was not capable of maintaining E. banksi populations under tolerable densities due to the unfavourable predator/prey ratios in summer and early autumn. Thirdly, this work aimed to describe the pest population structure and define a sampling plan. There were differences in the age structure on fruits and leaves, as well as between leaves from different flushes. Furthermore, over time, there were fluctuations in its composition correlated with variations in sex-ratio. No aggregation differences among plant strata were found, but there were significant differences between immature and adult stages, the females being the less aggregated. The high correlation of the total population with the motile forms and females allowed the use of both as a reference stage in the sampling plan, establishing a presence/absence sampling of 100 leaves for females or 400 leaves for motile forms. Finally, a recently described phytoseiid mite, Neoseiulus madeirensis Papadoulis & Kapaxidi, was found to be associated with E. banksi, suggesting that it could be a promising candidate for pest suppression. Fourthly, this work aimed to evaluate the potential of this predator to control pest populations. Neoseiulus madeirensis exhibited a short developmental time, high survival and reproductive rates feeding on E. banksi. The predator was fed mainly on immature stages, with eggs being the preferred stage, showing a type II functional response for all the prey stages tested, that stabilises at high prey densities with high egg laying. Survival, predation and reproduction values were the best obtained so far for any phytoseiid previously tested against E. banksi, making it a suitable candidate for the development of a biological control program based on augmentative releases, or importation aiming for the establishment of permanent populations on citrus.López Olmos, S. (2023). Towards the Integrated Management of the Texas Citrus Mite Eutetranychus Banksi (Acari: Tetranychidae) in Spain [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/20155

    Logical disagreement : an epistemological study

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    While the epistemic significance of disagreement has been a popular topic in epistemology for at least a decade, little attention has been paid to logical disagreement. This monograph is meant as a remedy. The text starts with an extensive literature review of the epistemology of (peer) disagreement and sets the stage for an epistemological study of logical disagreement. The guiding thread for the rest of the work is then three distinct readings of the ambiguous term ‘logical disagreement’. Chapters 1 and 2 focus on the Ad Hoc Reading according to which logical disagreements occur when two subjects take incompatible doxastic attitudes toward a specific proposition in or about logic. Chapter 2 presents a new counterexample to the widely discussed Uniqueness Thesis. Chapters 3 and 4 focus on the Theory Choice Reading of ‘logical disagreement’. According to this interpretation, logical disagreements occur at the level of entire logical theories rather than individual entailment-claims. Chapter 4 concerns a key question from the philosophy of logic, viz., how we have epistemic justification for claims about logical consequence. In Chapters 5 and 6 we turn to the Akrasia Reading. On this reading, logical disagreements occur when there is a mismatch between the deductive strength of one’s background logic and the logical theory one prefers (officially). Chapter 6 introduces logical akrasia by analogy to epistemic akrasia and presents a novel dilemma. Chapter 7 revisits the epistemology of peer disagreement and argues that the epistemic significance of central principles from the literature are at best deflated in the context of logical disagreement. The chapter also develops a simple formal model of deep disagreement in Default Logic, relating this to our general discussion of logical disagreement. The monograph ends in an epilogue with some reflections on the potential epistemic significance of convergence in logical theorizing

    Improving Cross-Lingual Transfer Learning for Event Detection

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    The widespread adoption of applications powered by Artificial Intelligence (AI) backbones has unquestionably changed the way we interact with the world around us. Applications such as automated personal assistants, automatic question answering, and machine-based translation systems have become mainstays of modern culture thanks to the recent considerable advances in Natural Language Processing (NLP) research. Nonetheless, with over 7000 spoken languages in the world, there still remain a considerable number of marginalized communities that are unable to benefit from these technological advancements largely due to the language they speak. Cross-Lingual Learning (CLL) looks to address this issue by transferring the knowledge acquired from a popular, high-resource source language (e.g., English, Chinese, or Spanish) to a less favored, lower-resourced target language (e.g., Urdu or Swahili). This dissertation leverages the Event Detection (ED) sub-task of Information Extraction (IE) as a testbed and presents three novel approaches that improve cross-lingual transfer learning from distinct perspectives: (1) direct knowledge transfer, (2) hybrid knowledge transfer, and (3) few-shot learning

    It doesn't end with closure:Optimizing health care throughout life after esophageal atresia repair

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    It doesn't end with closure:Optimizing health care throughout life after esophageal atresia repair

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    Quantifying Equity Risk Premia: Financial Economic Theory and High-Dimensional Statistical Methods

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    The overarching question of this dissertation is how to quantify the unobservable risk premium of a stock when its return distribution varies over time. The first chapter, titled “Theory-based versus machine learning-implied stock risk premia”, starts with a comparison of two competing strands of the literature. The approach advocated by Martin and Wagner (2019) relies on financial economic theory to derive a closed-form approximation of conditional risk premia using information embedded in the prices of European options. The other approach, exemplified by the study of Gu et al. (2020), draws on the flexibility of machine learning methods and vast amounts of historical data to determine the unknown functional form. The goal of this study is to determine which of the two approaches produces more accurate measurements of stock risk premia. In addition, we present a novel hybrid approach that employs machine learning to overcome the approximation errors induced by the theory-based approach. We find that our hybrid approach is competitive especially at longer investment horizons. The second chapter, titled “The uncertainty principle in asset pricing”, introduces a representation of the conditional capital asset pricing model (CAPM) in which the betas and the equity premium are jointly characterized by the information embedded in option prices. A unique feature of our model is that its implied components represent valid measurements of their physical counterparts without the need for any further risk adjustment. Moreover, because the model’s time-varying parameters are directly observable, the model can be tested without any of the complications that typically arise from statistical estimation. One of the main empirical findings is that the well-known flat relationship between average predicted and realized excess returns of beta-sorted portfolios can be explained by the uncertainty governing market excess returns. In the third chapter, titled “Multi-task learning in cross-sectional regressions”, we challenge the way in which cross-sectional regressions are used to test factor models with time-varying loadings. More specifically, we extend the procedure by Fama and MacBeth (1973) by systematically selecting stock characteristics using a combination of l1- and l2-regularization, known as the multi-task Lasso, and addressing the bias that is induced by selection via repeated sample splitting. In the empirical part of this chapter, we apply our testing procedure to the option-implied CAPM from chapter two, and find that, while variants of the momentum effect lead to a rejection of the model, the implied beta is by far the most important predictor of cross-sectional return variation

    Process-evaluation of forest aerosol-cloud-climate feedback shows clear evidence from observations and large uncertainty in models.

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    Natural aerosol feedbacks are expected to become more important in the future, as anthropogenic aerosol emissions decrease due to air quality policy. One such feedback is initiated by the increase in biogenic volatile organic compound (BVOC) emissions with higher temperatures, leading to higher secondary organic aerosol (SOA) production and a cooling of the surface via impacts on cloud radiative properties. Motivated by the considerable spread in feedback strength in Earth System Models (ESMs), we here use two long-term observational datasets from boreal and tropical forests, together with satellite data, for a process-based evaluation of the BVOC-aerosol-cloud feedback in four ESMs. The model evaluation shows that the weakest modelled feedback estimates can likely be excluded, but highlights compensating errors making it difficult to draw conclusions of the strongest estimates. Overall, the method of evaluating along process chains shows promise in pin-pointing sources of uncertainty and constraining modelled aerosol feedbacks

    LIPIcs, Volume 251, ITCS 2023, Complete Volume

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    LIPIcs, Volume 251, ITCS 2023, Complete Volum

    Assessment of microplastics and other contaminants in marine vertebrates from the Western Mediterranean Sea

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    Mediterranean marine biodiversity is under threat by pollution. For this reason, the main objective of this thesis was to analyse the presence of pollutants of concern in Mediterranean marine species. These studies are located in the Valencian Community (Spain), where we find loggerhead turtles, striped dolphins, and jewel lanternfish. Hence, we: 1. Analysed pesticides, heavy metals and phthalates in tissues of loggerhead turtles. 2. Studied microdebris present in beaches that are sporadically used as nesting grounds by loggerhead turtles. 3. Analysed striped dolphins# exposure to microplastics. 4. Quantified jewel lanternfish exposure to microplastics and tested their role as bioindicators of microplastic pollution in the bathypelagic environment. Results indicate the ubiquity of all the analysed pollutants. Pesticide analyses showed that all the analysed loggerheads (N=25) were exposed to 39 pesticides, of which 38.5% are forbidden in the EU. Results indicated low heavy metal burden. Mean concentrations of Cd, Pb and Hg were 0.04 μg/g., 0.09 μg/g. and 0.03 μg/g w.w. in fat and 0.05 μg/g, 0.08 μg/g and 0.04 μg/g w.w. in muscle. The juvenile size could account for these low concentrations. Seven phthalate metabolites in turtles were detected in more than 85% of the samples (DR>85%). The sum of the median concentration of the phthalate metabolites that had DR>85%, showed a negative correlation with size and also a significant increase in concentration from 2020 onwards; possibly explained by an increase in single-use plastic, or by uncontrolled wastewater discharges. Microdebris in beaches was ubiquitous although concentrations were not of concern for the success of loggerhead turtle clutches. In July, total mean±SD was 5.66 ± 3.66 MPs/kg at surface and 12.15 ± 7.76 MPs/kg at depth; while in November values were 6.45 ± 4.42 MPs/kg at surface and 5.51 ± 3.14 MPs/kg at depth. There were no significant differences among beaches, months, depths nor protection regime. Polymers found were commonly used in consumer goods and tires.MPs were present in 90.5% of the striped dolphins (N=43), although amount per dolphin was low and variable (median = 5, range = 0 - 82). Polyacrylamide, PET and HDPE were the most common polymers. MPs concentration from different periods of time (1989 # 2007/2010#2017) or locations were not different. Finally, the jewel lanternfish, (N=97), showed high frequency of occurrence of MPs, although a low body burden. Size and body condition were not correlated with the number of MPs. To sum up, an overview of the pollutants in the westernmost part of the Mediterranean Sea is provided, focusing on the aforementioned species and highlighting their potential as bioindicators

    Towards compact bandwidth and efficient privacy-preserving computation

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    In traditional cryptographic applications, cryptographic mechanisms are employed to ensure the security and integrity of communication or storage. In these scenarios, the primary threat is usually an external adversary trying to intercept or tamper with the communication between two parties. On the other hand, in the context of privacy-preserving computation or secure computation, the cryptographic techniques are developed with a different goal in mind: to protect the privacy of the participants involved in a computation from each other. Specifically, privacy-preserving computation allows multiple parties to jointly compute a function without revealing their inputs and it has numerous applications in various fields, including finance, healthcare, and data analysis. It allows for collaboration and data sharing without compromising the privacy of sensitive data, which is becoming increasingly important in today's digital age. While privacy-preserving computation has gained significant attention in recent times due to its strong security and numerous potential applications, its efficiency remains its Achilles' heel. Privacy-preserving protocols require significantly higher computational overhead and bandwidth when compared to baseline (i.e., insecure) protocols. Therefore, finding ways to minimize the overhead, whether it be in terms of computation or communication, asymptotically or concretely, while maintaining security in a reasonable manner remains an exciting problem to work on. This thesis is centred around enhancing efficiency and reducing the costs of communication and computation for commonly used privacy-preserving primitives, including private set intersection, oblivious transfer, and stealth signatures. Our primary focus is on optimizing the performance of these primitives.Im Gegensatz zu traditionellen kryptografischen Aufgaben, bei denen Kryptografie verwendet wird, um die Sicherheit und Integrität von Kommunikation oder Speicherung zu gewährleisten und der Gegner typischerweise ein Außenstehender ist, der versucht, die Kommunikation zwischen Sender und Empfänger abzuhören, ist die Kryptografie, die in der datenschutzbewahrenden Berechnung (oder sicheren Berechnung) verwendet wird, darauf ausgelegt, die Privatsphäre der Teilnehmer voreinander zu schützen. Insbesondere ermöglicht die datenschutzbewahrende Berechnung es mehreren Parteien, gemeinsam eine Funktion zu berechnen, ohne ihre Eingaben zu offenbaren. Sie findet zahlreiche Anwendungen in verschiedenen Bereichen, einschließlich Finanzen, Gesundheitswesen und Datenanalyse. Sie ermöglicht eine Zusammenarbeit und Datenaustausch, ohne die Privatsphäre sensibler Daten zu kompromittieren, was in der heutigen digitalen Ära immer wichtiger wird. Obwohl datenschutzbewahrende Berechnung aufgrund ihrer starken Sicherheit und zahlreichen potenziellen Anwendungen in jüngster Zeit erhebliche Aufmerksamkeit erregt hat, bleibt ihre Effizienz ihre Achillesferse. Datenschutzbewahrende Protokolle erfordern deutlich höhere Rechenkosten und Kommunikationsbandbreite im Vergleich zu Baseline-Protokollen (d.h. unsicheren Protokollen). Daher bleibt es eine spannende Aufgabe, Möglichkeiten zu finden, um den Overhead zu minimieren (sei es in Bezug auf Rechen- oder Kommunikationsleistung, asymptotisch oder konkret), während die Sicherheit auf eine angemessene Weise gewährleistet bleibt. Diese Arbeit konzentriert sich auf die Verbesserung der Effizienz und Reduzierung der Kosten für Kommunikation und Berechnung für gängige datenschutzbewahrende Primitiven, einschließlich private Schnittmenge, vergesslicher Transfer und Stealth-Signaturen. Unser Hauptaugenmerk liegt auf der Optimierung der Leistung dieser Primitiven
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