Cervical cancer precursors and hormonal contraceptive use in HIV-positive women: application of a causal model and semi-parametric estimation methods.

OBJECTIVE: To demonstrate the application of causal inference methods to observational data in the obstetrics and gynecology field, particularly causal modeling and semi-parametric estimation. BACKGROUND: Human immunodeficiency virus (HIV)-positive women are at increased risk for cervical cancer and its treatable precursors. Determining whether potential risk factors such as hormonal contraception are true causes is critical for informing public health strategies as longevity increases among HIV-positive women in developing countries. METHODS: We developed a causal model of the factors related to combined oral contraceptive (COC) use and cervical intraepithelial neoplasia 2 or greater (CIN2+) and modified the model to fit the observed data, drawn from women in a cervical cancer screening program at HIV clinics in Kenya. Assumptions required for substantiation of a causal relationship were assessed. We estimated the population-level association using semi-parametric methods: g-computation, inverse probability of treatment weighting, and targeted maximum likelihood estimation. RESULTS: We identified 2 plausible causal paths from COC use to CIN2+: via HPV infection and via increased disease progression. Study data enabled estimation of the latter only with strong assumptions of no unmeasured confounding. Of 2,519 women under 50 screened per protocol, 219 (8.7%) were diagnosed with CIN2+. Marginal modeling suggested a 2.9% (95% confidence interval 0.1%, 6.9%) increase in prevalence of CIN2+ if all women under 50 were exposed to COC; the significance of this association was sensitive to method of estimation and exposure misclassification. CONCLUSION: Use of causal modeling enabled clear representation of the causal relationship of interest and the assumptions required to estimate that relationship from the observed data. Semi-parametric estimation methods provided flexibility and reduced reliance on correct model form. Although selected results suggest an increased prevalence of CIN2+ associated with COC, evidence is insufficient to conclude causality. Priority areas for future studies to better satisfy causal criteria are identified.

Comportement et rendement scolaire au début du primaire : les attributions causales et d'intentions, des processus en jeu?

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

The Causal Links between FDI and Economic Growth in Developing Countries: A Case Study of the Republic of Rwanda

The study examines the short-run and long-run causality running from real economic growth to real foreign direct investment inflows (RFDI). Other variables such as education (involving combination of primary, secondary and tertiary enrolment as a proxy to education), real development finance, unskilled labour, to real RFDI inflows are included in the study. The time series data covering the period of 1983 -2013 are examined. First, I applied Augmented Dicky-Fuller (ADF) technique to test for unit root in variables. Findings shows all variables integrated of order one [I(1)]. Thereafter, Johansen Co-integration Test (JCT) was conducted to establish the relationship among variables. Both trace and maximum Eigen value at 5% level of significance indicate 3 co-integrated equations. Vector error correction method (VECM) was applied to capture short and long-run causality running from education, economic growth, real development finance, and unskilled labour to real foreign direct investment inflows in the Republic of Rwanda. Findings shows no short-run causality running from education, real development finance, real GDP and unskilled labour to real FDI inflows, however there were existence of long-run causality. This can be interpreted that, in the short-run; education, development finance, finance and economic growth does not influence inflows of foreign direct investment in Rwanda; but it does in long-run. From the policy perspective, the Republic of Rwanda should focus more on long term goal of investing in education to improve human capital, undertake policy reforms that promotes economic growth, in addition to promoting good governance to attract development finance – especially from Nordics countries (particularly Norway and Denmark).

Reconceptualising International Intervention: Statebuilding, ‘Organic Processes’ and the Limits of Causal Knowledge

This article examines the transformation in the conceptual understanding of international intervention over the last two decades. It suggests that this conceptual shift can be usefully interrogated through its imbrication within broader epistemological shifts highlighting the limits of causal knowledge claims: heuristically framed in this article in terms of the shift from policy interventions within the problematic of causation to those concerned with the management of effects. In this shift, the means and mechanisms of international intervention have been transformed, no longer focused on the universal application of Western causal knowledge through policy interventions but rather on the effects of specific and unique local and organic processes at work in societies themselves. The focus on effects takes the conceptualisation of intervention out of the traditional terminological lexicon of International Relations theory and instead recasts problems in increasingly organicised ways, suggesting that artificial or hubristic attempts at socio-political intervention should be excluded or minimised.

Automated Equation Formulation for Causal Loop Diagrams

The annotation of Business Dynamics models with parameters and equations, to simulate the system under study and further evaluate its simulation output, typically involves a lot of manual work. In this paper we present an approach for automated equation formulation of a given Causal Loop Diagram (CLD) and a set of associated time series with the help of neural network evolution (NEvo). NEvo enables the automated retrieval of surrogate equations for each quantity in the given CLD, hence it produces a fully annotated CLD that can be used for later simulations to predict future KPI development. In the end of the paper, we provide a detailed evaluation of NEvo on a business use-case to demonstrate its single step prediction capabilities.

Finite Population Inference for Causal Parameters

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

Élaboration et standardisation d'un test d'attitudes : le QACSS (Questionnaire sur les attributions causales en situations scolaires)

Croyant que la connaissance approfondie du style attributionnel des élèves inscrits au cégep pourrait être un pas de plus vers la connaissance des processus psycho-cognitifs de l'élève en situations d'apprentissage scolaire et également une piste d'intervention pour réduire les abandons et les échecs au collégial, nous avons élaboré et validé un questionnaire étudiant les attributions causales reliées à des situations scolaires, le QACSS. La présente recherche correspond à la première étape d'une étude portant sur le style attributionnel des cégépiens. Nous basant sur la théorie des attributions de Weiner et sur l'étude expérimentale de l'ASQ (Attributionnal Style Questionnaire) de Peterson et al. (1982), nous avons élaboré et procédé à l'expérimentation du QACSS auprès de 317 élèves de niveau collégial, inscrits dans divers programmes collégiaux, au secteur régulier. Nous présentons et analysons, dans ce rapport, les résultats obtenus lors de notre étude de validité et de fidélité et nous discutons des principales questions surgies lors de cette analyse. En conclusion, nous affirmons que le QACSS peut être considéré comme un outil fiable de la mesure des attributions causales reliées aux situations scolaires.

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.

The Self as a Moral Basis: Do Our Own Patterns of Behavior Affect our Moral Attributions?

To determine which actions are morally acceptable, psychologists typically focus on decision making within existing moral paradigms. However, this fails to comment upon individual and social processes, such as attribution, that determine morality. To address these processes, this study had participants respond to morally-charged scenarios by rating the immorality of an actor who did not tip a waiter (n = 125), was partial to infidelity (n = 128), and texted while driving (n = 128). Participants also completed an empathy measure, and provided their own frequency of engaging in certain behaviors, including those featured in the scenarios. Immorality ratings were compared to the participants’ own frequency of the scenario action (hypothesized to lower ratings), as well as empathy and outcome severity (both hypothesized to increase ratings). Findings were assessed in three regressions, one per scenario. Behavioral similarity predicted immorality ratings in each (p ≤ .03), empathy predicted ratings only for not tipping a waiter (p = .04), while outcome severity was un-predictive in each scenario. Theoretical implications, directions for future research, and limitations of the study are discussed.

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

International audience

Conducta prosocial y autoatribuciones académicas en Educación Secundaria Obligatoria

Este estudio presenta los resultados sobre la relación que existe entre las autoatribuciones académicas en lenguaje y matemáticas en una muestra de 2.022 estudiantes de Educación Secundaria de 12 a 16 años. Los adolescentes fueron seleccionados aleatoriamente de 20 escuelas urbanas y rurales en las provincias de Alicante y Murcia, España. La conducta prosocial fue codificada con el Teenage Inventory of Social Skills y las autoatribuciones académicas fueron medidas mediante la Escala de Atribución Causal de Sydney (Sydney Attribution Scale, SAS; Marsh, 1984). El 17.35% de estudiantes de ESO fueron identificados como prosociales. Los chicos de 2º de ESO y las chicas de 4º de ESO presentaron la menor y mayor prevalencia puntual de conducta prosocial, respectivamente. Respecto a la asignatura de lenguaje, los estudiantes prosociales atribuyen significativamente el éxito a la capacidad, el esfuerzo y, en menor medida, a causas externas. En cuanto a la asignatura de matemáticas, los estudiantes prosociales atribuyeron el éxito significativamente más al esfuerzo y significativamente menos a causas externas, mientras que atribuyeron el fracaso significativamente más a la falta de esfuerzo. Además, los datos han permitido crear un modelo de regresión logística que permite hacer estimaciones correctas respecto a la probabilidad de éxito académico en matemáticas, en lenguaje y en todas las asignaturas aprobadas en estudiantes prosociales de E.S.O. a partir de las puntuaciones en atribuciones académicas.