ON BASELINE CONDITIONS FOR ZERO-INFLATED LONGITUDINAL COUNT DATA

We describe a mixed-effects hurdle model for zero-inflated longitudinal count data, where a baseline variable is included in the model specification. Association between the count data process and the endogenous baseline variable is modeled through a latent structure, assumed to be dependent across equations. We show how model parameters can be estimated in a fnite mixture context, allowing for overdispersion, multivariate association and endogeneity of the baseline variable. The model behavior is investigated through a large scale simulation experiment. An empirical example on health care utilization data is provided.Hurdle model - Baseline conditions - Longitudinal count data - Zero-inflation.

OPTIMIZATION OF THE ORGANIC FRUIT AND VEGETABLE DRYING PROCESS BY USING NON-DESTRUCTIVE TECHNIQUES

The aim of this project is the obtainment of a smart-prototype drier able to improve the hot-air drying process of organic fruits and vegetables using non-destructive technologies. Thus, a quality by design (QbD) approach has been followed in order to improve products quality and control strategy. For the intended purpose, both at-line near infrared spectroscopy (NIRS) and in-line computer vision (CV) techniques were tested. The data matrices were then subjected to chemometrics analysis in order to develop prediction and classification models able to follow up physico-chemical changes and recognise dehydration phases, respectively. Thermal (i.e. hot-water, microwave or steam blanching) and dipping (i.e. non-reducing sugar and/or ascorbic acid) pre-treatments were investigated as viable alternatives to reduce browning occurrence. Excellent performances (R2 = 0.91 - 0.98) were achieved in predicting physico-chemical changes (e.g. water activity, moisture content, soluble solid content, etc.) using NIRS coupled with partial least squares regression algorithm for both apple (var. Gala) and carrot (var. Romance). The prediction of colour changes using NIR wavelengths gave good results (R2 = 0.80 - 0.87), probably due to the fact that it is an indirect measurement. Features selection led to comparable prediction performances while reducing model complexity. Similarly, partial least squares discriminant analysis PLS-DA provided from good (> 0.85) to excellent (> 0.95) results in terms of sensitivity and specificity rates for the recognition of drying phases. Finally, computer-vision analysis showed potentiality in simultaneously monitoring morphological (e.g. area shrinkage and eccentricity), colour (CIELab) and physicochemical (moisture and drying rate) changes on apple cylinders during the process. Indeed, linear regression models gave excellent results (R2 = 0.993-0.999) in predicting changes in moisture content on the basis of the area shrinkage. The results confirm the feasibility of an accurate smart-control of the drying process based on non-destructive technology and set the basis for a scale up of the process

Cross-sectional methods for empirical asset pricing

This thesis develops new methods in empirical asset pricing which are valid when a large number of assets is available for the analysis. The work is divided in three main chapters, each of them focusing on different aspects and issues typically related to asset-pricing models. The fir st chapter introduces a methodology for estimating and testing beta-pricing models when a large number of assets is available for investment but the number of time-series observations is fixed. We first consider the case of correctly specified models with constant risk premia, and then extend our framework to deal with time-varying risk premia, potentially misspecified models, firm characteristics, and unbalanced panels. We show that our large cross-sectional framework poses a serious challenge to common empirical findings regarding the validity of beta-pricing models. Firm characteristics are found to explain a much larger proportion of variation in estimated expected returns than betas. The second chapter investigates the effect of model misspecification on mean-variance portfolios and show how asset-pricing theory and asymptotic analysis can mitigate misspeci cation. The analysis is founded on the Arbitrage Pricing Theory (APT), because it allows for pricing errors. The APT is extended to show it can capture not just small pricing errors unrelated to factors but also large pricing errors from mismeasured and missing factors. The key insight is that, instead of treating misspecification directly in the mean-variance portfolio, it is better to fi rst decompose the portfolio into a "beta" portfolio that depends only on factor risk premia and an "alpha" portfolio that depends only on pricing errors. Then, as the number of assets increases, we show that the weights of the alpha portfolio dominate those of the beta portfolio, leading to mean-variance portfolio weights that are immune to beta misspecification. For the alpha portfolio, misspecification is treated by imposing the APT restriction, which serves as an identification condition and a shrinkage constraint. Using simulations, we illustrate how our theoretical insights lead to a significant improvement in the out-of-sample performance of mean-variance portfolios. The third chapter analyzes the large cross-sectional properties of the standard two-pass methodology, when useless factors are included in the beta-pricing specification. When the number of time-series observations, T, is assumed to be fixed, and contrary to the conventional large-T framework, we find that the simple two-pass OLS estimator of risk premia exhibits desirable asymptotic properties that can be used to detect useless factors. In particular, we derived correctly-sized t-ratios, F-tests and goodness-of- t measures that allow us to implement a powerful statistical strategy to test for factors that can be potentially irrelevant for the analysis. The results hold also under the assumption of potential model misspecification. The validity of our results is assessed by means of simulation exercises.Open Acces

A Declaration of Interdependence: An Analysis of Multilevel Governance and the Role of Municipal Governments as Climate Policy Entrepreneurs

Since March 2019, municipalities in Ontario have become increasingly conscious of the role of local government in addressing the global climate emergency. Although minor departmental initiatives such as green infrastructure development policies are understood as environmentally conscious, the larger policy network of municipal governance has only recently entered the climate change mitigation and adaptation policy field. Declarations of climate emergencies are a modern way for municipal governments to signal both interest and intended action in climate change policies. In one year, Ontario municipal climate emergencies increased from 0 to 47, with the 47 municipalities representing nearly 90% of Ontario’s population. Such interest prompted this analysis of the policymaking structure of local government and the means by which climate change policy could be introduced and implemented. Policymaking and capacity theories are used to determine how municipalities can work with upper levels of government and advocacy groups in order to engage with the policymaking process from a climate change perspective

Novos ruídos, novas vozes

Como artista interessada em Noise e filha de pais surdos, abordarei a questão do ruído e da contracultura a partir da questão da surdez e das vozes não cultivadas. Nas sociedades de pessoas sem deficiências a voz é um produto cultural e certas vozes percebidas como “outras”, imperfeitas, “barulhentas”, podem gerar discursos ligados ao compartilhamento de espaços sonoros, perturbações e inclusões. Tomo a  paisagem sonora como um ambiente social e político, e os corpos ali imersos são considerados para além da escuta, incorporando o espectro total de suas capacidades, em termos rítmico-analíticos. A paisagem sonora, entendida dentro dos limites da audibilidade, expele e rejeita comunidades que carregam o estigma da “deficiência” como é o caso da comunidade dos surdos. Este exercício teórico é acompanhado por exemplos de arte contemporânea e de referências histórico-tecnológicas, apontando para "atos de silenciamento" e "atos de ruído". Ao mesmo tempo, sublinha o valor de corpos "desviantes" como corpos que resistem. O artigo termina com o testemunho de uma dançarina surda que usou meus textos para produzir seus dois últimos trabalhos. Apesar de serem considerados deficientes ou desviantes, Surdos são um exemplo significativo de agentes contraculturais em sociedades plenamente habilitadas nas capacidades da fala e da escuta.  As an artist interested in Noise, and a CODA (child of deaf adults), I will tackle the issue of noise and counterculture from the entry point of deafness and un-cultured voices. In ableist societies the voice is a cultural product, and certain voices, perceived as “other”, flawed, “noisy”, can open up discourses related to shared sonic spaces, disruption, and inclusivity. Soundscape is here described as a social and political environment, and the bodies immersed in it are considered according to the entire spectrum of their capacities, beyond listening, in rhythmanalytical terms. Soundscape, understood within the thresholds of audibility, expels and rejects communities which carry the stigma of “handicap”, such as Deaf communities. This theoretical exercise is accompanied by examples from contemporary art and technological-historical references, pointing at “acts of silencing” and “acts of noising”, while underlining the value of “deviant” bodies as resistant bodies. The paper ends with the testimony of a Deaf dancer who used my writings to produce her last two shows. I will refer to the audiological deaf using the lowercase, and capitalize the linguistic minority: Deaf. Despite being considered disabled, or deviant, Deaf bodies are the last example of countercultural agents in all-speaking and all-hearing ableist societies