Finite Population Inference for Causal Parameters

Thesis (Ph.D.)--University of Washington, 2016-08

Energy systems analysis of transboundary river basins in a nexus approach: the Sava river basin study case

Resource management policies are frequently designed and planned to target specific needs of particular sectors, without taking into account the interests of other sectors who share the same resources. In a climate of resource depletion, population growth, increase in energy demand and climate change awareness, it is of great importance to promote the assessment of intersectoral linkages and, by doing so, understand their effects and implications. This need is further augmented when common use of resources might not be solely relevant at national level, but also when the distribution of resources ranges over different nations. This dissertation focuses on the study of the energy systems of five south eastern European countries, which share the Sava River Basin, using a water-food(agriculture)-energy nexus approach. In the case of the electricity generation sector, the use of water is essential for the integrity of the energy systems, as the electricity production in the riparian countries relies on two major technologies dependent on water resources: hydro and thermal power plants. For example, in 2012, an average of 37% of the electricity production in the SRB countries was generated by hydropower and 61% in thermal power plants. Focusing on the SRB, in terms of existing installed capacities, the basin accommodates close to a tenth of all hydropower capacity while providing water for cooling to 42% of the net capacity of thermal power currently in operation in the basin. This energy-oriented nexus study explores the dependency on the basin’s water resources of the energy systems in the region for the period between 2015 and 2030. To do so, a multi-country electricity model was developed to provide a quantification ground to the analysis, using the open-source software modelling tool OSeMOSYS. Three main areas are subject to analysis: first, the impact of energy efficiency and renewable energy strategies in the electricity generation mix; secondly, the potential impacts of climate change under a moderate climate change projection scenario; and finally, deriving from the latter point, the cumulative impact of an increase in water demand in the agriculture sector, for irrigation. Additionally, electricity trade dynamics are compared across the different scenarios under scrutiny, as an effort to investigate the implications of the aforementioned factors in the electricity markets in the region.

CAUSAL INFERENCE WITH A CONTINUOUS TREATMENT AND OUTCOME: ALTERNATIVE ESTIMATORS FOR PARAMETRIC DOSE-RESPONSE FUNCTIONS WITH APPLICATIONS.

Causal inference with a continuous treatment is a relatively under-explored problem. In this dissertation, we adopt the potential outcomes framework. Potential outcomes are responses that would be seen for a unit under all possible treatments. In an observational study where the treatment is continuous, the potential outcomes are an uncountably infinite set indexed by treatment dose. We parameterize this unobservable set as a linear combination of a finite number of basis functions whose coefficients vary across units. This leads to new techniques for estimating the population average dose-response function (ADRF). Some techniques require a model for the treatment assignment given covariates, some require a model for predicting the potential outcomes from covariates, and some require both. We develop these techniques using a framework of estimating functions, compare them to existing methods for continuous treatments, and simulate their performance in a population where the ADRF is linear and the models for the treatment and/or outcomes may be misspecified. We also extend the comparisons to a data set of lottery winners in Massachusetts. Next, we describe the methods and functions in the R package causaldrf using data from the National Medical Expenditure Survey (NMES) and Infant Health and Development Program (IHDP) as examples. Additionally, we analyze the National Growth and Health Study (NGHS) data set and deal with the issue of missing data. Lastly, we discuss future research goals and possible extensions.

Caracterización del agente causal de la producción radicular del aguacate y Trichoderma sp., como potencial agente de control biológico en Nicaragua.

En el cultivo de aguacate (Persea americana Mill.) se presentan problemas fitosanitarios importantes dentro de los cuales sobresalen por su relevancia las enfermedades de la raíz. Un fitopatógeno limitante de este cultivo es el oomicete Phytophthora cinnamomi Rands, que puede causar pérdidas hasta del 90%. Por tal razón el principal objetivo del estudio fue generar información acerca de la etiología del agente causal de la pudrición radicular del aguacate utilizando marcadores morfológicos y moleculares, además de proponer alternativas de manejo de carácter biológico que estén enmarcadas dentro de un programa de manejo integrado de la enfermedad. Se realizaron colectas de muestras de suelo en cuatro localidades del departamento de Masaya. La identificación morfológica del patógeno se realizó mediante claves taxonómicas y se confirmó a través de la técnica PCR-RFLP. Se identificó a P. cinnamomi como el principal agente causal de la pudrición radicular del aguacate. Los aislados de P. cinnamomi fueron enfrentados con Trichoderma sp por el método de cultivo dual en cajas Petri con medio PDA. Se determinó el porcentaje de inhibición de crecimiento radial (PICR) a las 72 horas, así como el grado de antagonismo de cada una de las cepas de Trichoderma sp utilizadas en el estudio. Las cepas de Trichoderma al enfrentarlas a aislados del patógeno P. cinnamomi se ubicaron en las Clases 1 y 2 de la escala de evaluación, por lo tanto se consideraron altamente antagonistas. Existe la posibilidad de manejo biológico de las poblaciones de P. cinnamomi con microorganismos antagonistas del género Trichoderma no solamente en agroecosistemas de aguacate, sino también en otros sistemas agrícolas y forestales donde el patógeno esté presente.

Causal structure of the entanglement renormalization ansatz

We show that the multiscale entanglement renormalization ansatz (MERA) can be reformulated in terms of a causality constraint on discrete quantum dynamics. This causal structure is that of de Sitter space with a flat space-like boundary, where the volume of a spacetime region corresponds to the number of variational parameters it contains. This result clarifies the nature of the ansatz, and suggests a generalization to quantum field theory. It also constitutes an independent justification of the connection between MERA and hyperbolic geometry which was proposed as a concrete implementation of the AdS-CFT correspondence.

Using Causal Models for the Calculation of Direct and Indirect Effects: An Example From Occupational Health

International audience

Causal factors of anxiety symptoms in children

Aim: The present work aimed to investigate the impact of the child’s cognitions associated with ambiguous stimuli that refer to anxiety, both parents’ fears and anxiety, and parents’ attributions to the child’s interpretations of ambiguous stimuli on child anxiety. The influence of parental modelling on child’s cognitions was also analyzed. Method: The final sample was composed of 111 children (62 boys; 49 girls) with ages between 10 and 11 years (M = 10.6, SD = 0.5) from a community population, and both their parents. The variables identified as most significant were included in a predictive model of anxiety. Results: Results revealed the children’s thoughts (positive and negative) related to ambiguous stimuli that describe anxiety situations. Parents’ fears and mothers’ anxiety significantly predict children’s anxiety. Those variables explain 29% of the variance in children general anxiety. No evidence was found for a direct parental modeling of child cognitions. Conclusion: Children’s positive thoughts seem to be cognitive aspects that buffer against anxiety. Negative thoughts are vulnerability factors for the development of child anxiety. Parents’ fears and anxiety should be analyzed in separate as they have distinct influences over children’s anxiety. Mothers’ fears contribute to children’s anxiety by reducing it, revealing a possible protective effect. It is suggested that the contribution of both parents’ fears to children’s anxiety may be interpreted acknowledging the existence of “psychological and/or behavioral filters”. Mothers’ filters seem to be well developed while fathers’ filters seem to be compromised. The contribution of mothers’ anxiety (but not fathers’ anxiety) to children’s anxiety is also understood in light of the possible existence of a “proximity space” between the child and parents, which is wider with mothers than with fathers.

Pesquisa de fungos endofíticos presentes em videira (Vitis vinifera L.) com capacidade para inibir o crescimento do agente causal da podridão negra (Guignardia bidwellii)

Neste trabalho testou-se o potencial antagonista de 16 fungos endofíticos isolados de videiras (Vitis vinifera L.), de castas representativas do Alentejo produzidas em modo de proteção integrada e em modo biológico, contra Guignardia bidwellii. Os isolados identificados após ITS-PCR e sequenciação pertencem aos géneros Epicoccum, Alternaria, Botrytis, Athelia, Phoma e Gibberella. Os isolados testados mostraram atividade antagonista contra G. bidwellii quer por inibição direta, quer através da produção de compostos voláteis, à exceção dos dois isolados de B. cinerea. No entanto, todos os isolados produziram alguns compostos voláteis com reconhecida atividade antimicrobiana, tais como benzaldeído, 3-metil-1-butanol e derivados de ácido propanoico. Foi ainda observado que seis dos isolados produziram também metabolitos não voláteis com capacidade de inibir o crescimento de G. bidwellii. Os resultados obtidos vêm mostrar o potencial dos fungos endofíticos como agentes de luta biológica no controlo de G. bidwellii, podendo constituir novas alternativas no âmbito de Proteção de Plantas; ABSTRACT: Endophytic fungi present in grapevines (Vitis vinifera L.) with the ability to inhibit the growth of the causal agent of black rot (Guignardia bidwellii) In this work the antagonistic potential of 16 endophytic grapevine fungi isolates (Vitis vinifera L.), from representative cultivars of the Alentejo region produced either under integrated pest management or organic mode, was tested against Guignardia bidwellii. Isolates were identified through ITS-PCR and sequencing, as belonging to the genera Epicoccum, Alternaria, Botrytis, Athelia, Phoma and Gibberella. Isolates showed antagonist activity against G. bidwellii either by direct inhibition or through the production of volatile compounds, with the exception of two isolates of B. cinerea. Nevertheless, all isolates produced volatile compounds with known antimicrobial activity such as benzaldehyde, 3-methyl-1-butanol and propionic acid derivatives. Additionally, six isolates produced non-volatile metabolites with the ability to inhibit G. bidwellii growth. These results show the potential that endophytic fungi have as agents for biological control of G. bidwellii, opening new options in the field of Plant Protection.

Post-transcriptional silencing of the SGE1 gene induced by a dsRNA hairpin in Fusarium oxysporum f. sp cubense, the causal agent of Panama disease.

Fusarium oxysporum f. sp cubense (Foc), the causal agent of Panama disease, is responsible for economic losses in banana crops worldwide. The identification of genes that effectively act on pathogenicity and/or virulence may contribute to the development of different strategies for disease control and the production of resistant plants. The objective of the current study was to analyze the importance of SGE1 gene expression in Foc virulence through post-transcriptional silencing using a double-stranded RNA hairpin.

Modelo causal de los factores asociados al aprendizaje autorregulado como mediador del rendimiento académico en estudiantes universitarios

El objetivo general de esta investigación fue medir, describir, relacionar y analizar las estrategias cognitivas, metacognitivas y contextuales así como la motivación hacia el aprendizaje de estudiantes universitarios mexicanos, y su relación con diversas variables educativas y socio-familiares como determinantes del rendimiento académico en la universidad, desde la teoría social-cognitiva del aprendizaje autorregulado. Mediante la aplicación y el análisis posterior de las bases de datos institucionales obtenidas del Examen Nacional de Ingreso al Nivel Superior (EXANI-II) y del Cuestionario de Contexto del Centro Nacional de Evaluación (CENEVAL) de los 1,140 estudiantes de licenciatura de la Universidad Autónoma de Yucatán (UADY) que respondieron el Cuestionario de Motivación y Estrategias de Aprendizaje (CMEA) diseñado a partir de la traducción, adaptación y validación del Motivated Strategies for Learning Questionnaire (MSLQ). El tipo de investigación seleccionada fue cuasiexperimental, descriptivo y correlacional-causal. Se realizó un análisis de frecuencias de las variables descriptivas, se calcularon los estadísticos descriptivos de los resultados en las sub-escalas del CMEA, y análisis de medias mediante la prueba t de Student para muestras no relacionadas y análisis de varianza. Finalmente, se calcularon los índices de correlación entre las variables educativas, socio-familiares, motivacionales, y de uso de estrategias y el rendimiento académico. Para evaluar la hipótesis general del ajuste del modelo teórico a los datos se utilizó el programa SPSS Amos 16 y el paquete sem 0.9-14 en R 2.8.0...

The water-food nexus and the role of demand management

With the global population projected to reach 9 billion in 2050, demand for food is expected to increase by over 50% in 2030 and 70% in 2050 (UN-Water, 2013). Already agriculture is the largest user of water with irrigation accounting for nearly 70% of all freshwater withdrawals (UN-Water, 2016).

Resolución 137 del 15 de agosto de 2014: ¿Cuál es el alcance del control de legalidad de la cámara de comercio respecto de los actos y documentos sujetos a registro? ¿Cuándo existe duda razonable respecto de los elementos formales con base en los que se configuro una decisión pueden constituirse como causal de abstención del registro?

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