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A spatial decision support system to assess personal exposure to air pollution integrating sensor measurements
Get PDFRecent epidemiological studies have reinforced the link between short and long-term exposure to air pollutants and adverse effects on public health especially over the weaker part of the population, like children and older adults. The creation of simple tools to locate sensible areas as well as of dedicated Spatial Decision Support System (SDSS) to improve the management of pollution risk areas system is strongly advised. The aim of this work is to develop a SDSS methodology, based on easy to find data and usable by decision makers, to assess and reduce the impact of air pollutants in a urban context. To achieve this goals I tested the exploitability of a set of low-cost sensors for outdoor air quality monitoring, I characterized the urban micro-environments and the spatial variability of air pollutants using remote sensing compared to field data and eventually I developed a SDSS to improve the public health designing and comparing different scenarios. The city centre of Edinburgh has been used as study case for the purposed methodology. To test the reliability and applicability of low cost sensors as proxies for remote sensed data, we conducted a measurements campaign to compare the observed data between an official measurements station (OMS) in Trento (Italy) and electrochemical and thick film sensors respectively of Carbon Monoxide (CO) and Ozone (). Due to data quality and availability we decided to characterize the urban micro-environments of Edinburgh (Scotland, UK) in eight main classes (water, grass, vegetation, road, car, bus, buildings and shadow) combining the Geographic Object-Based Image Analysis (GEOBIA) with Machine Learning algorithms to process the high resolution (0.25m x 0.25m) RGB aerial ortho-rectified images. This land-use characterization combined with other geographical informations, like the classification of the roads and the urban morphology, were compared with 37 Nitrogen Dioxide (NO2) concentration data, collected using passive tubes during a six week campaign of measurements conducted by the school of Chemistry of the University of Edinburgh.
I developed a new open-source GIS python library (PyGRASS), integrated in the stable release of GRASS GIS, to speed-up the prototyping phase and to create and test new GIS tools and methodologies. Different studies on SDSS were carried out to implement procedures and models. Based on these models and data all the factors (land-use, roads and geo-morphological features) were ranked to identify which are driving forces for urban air quality and to help decision makers to develop new policies. The sensor tested in Trento revealed an evident drift in measurement residues for CO, furthermore the measurements were also quite sensitive to external factors such as temperature and humidity. Since these sensors required frequent recalibration in order to obtain reliable results, their use was not as low-cost as expected. The characterization of urban land-use in Edinburgh with GEOBIA and machine learning provided an overall accuracy of 93.71\% with a Cohen's k of 0.916 using a train/test dataset of 9301 objects. The data confirm the assumption that air concentration is strongly dependent on geographical position and it is strongly influenced by the position of the pollutant's source. Using the results of the tests and remote sensing analysis, I developed an SDSS. Starting from the current situation, I designed three scenarios to assess the effect that different policies and actions could have on improving air quality at on the local and district level. The outcomes of this work can be used to define and compare different scenarios and develop effective policies to reduce the impact of air pollutants in an urban context using simple and easy to find data. The GIS-based tool can help to identify critical areas before deploying sensors and splitting the study area in homogeneous micro-environments clusters. The model is easy to expand following different procedures
Three essays in experimental and labor economics
No full textThis thesis collects three independent essays. Two of them relate to experimental economics, and one to labor economics. The first essay explores through a laboratory experiment the relationship between cognitive costs and imitation dynamics. The second essay investigates in an experimental setting information aversion towards bad/good news about ones’ own condition, and tests the effect
of the possibility of exerting effort, which may improve one’s own condition, on the willingness to acquire more detailed personal information. The third essay proposes an empirical application aiming at studying gender discrimination in a research context, and in particular whether the gender composition of evaluating commissions affects the hiring of women in research activities
Verrechtlichung von Geschichte. Parlamentarische Debatten um die gesetzlichen Bestimmungen gegen Holocaustleugnung in Österreich und Deutschland
Get PDFIn der Dissertation mit dem Titel „Verrechtlichung von Geschichte. Parlamentarische Debatten um die gesetzlichen Bestimmungen gegen Holocaustleugnung in Österreich und Deutschland“ habe ich die strafrechtlichen Bestimmungen gegen Holocaust-Leugnung in Deutschland und Österreich untersucht. Im Vordergrund stand die Frage, wie ein historisches Ereignis mit Hilfe politischer und juristischer Terminologie so gefasst und normiert werden konnte, dass die Leugnung desselben seitdem mit Hilfe des Rechts bestraft werden kann. Dazu wurden vor allem jene parlamentarischen Vorgänge und Debatten untersucht, die der Verabschiedung der Gesetze vorausgegangen sind. Die Auswertung dieser Quellen hilft auch zu verstehen, weshalb und in welcher Form die Logik dieser Gesetze in den letzten zwanzig Jahren von anderen Staaten übernommen und auf andere historische Ereignisse ausgeweitet worden ist. Neben diesem umfangreichen empirischen Teil, der auf die jeweiligen historischen Spezifika eingeht, beinhaltet die Dissertation einen stärker analytisch ausgerichteten resümierenden Schlussteil, in dem ich versucht habe, mit thesenhaften Beobachtungen das Phänomen und die ideengeschichtliche Genese der Holocaust-Leugnungsgesetze nachzuzeichnen. Diese Beobachtungen umfassen unter anderem die Bereiche Geschichtspolitik, Rechtspolitik, Sprachpolitik oder auch Wissenschaftspolitik und gehen aus unterschiedlichen Blickwinkeln der Frage nach, auf welche Weise die Gesetze begründet, legitimiert und kritisiert worden sind und immer noch werden
Functional analysis of Arabidopsis thaliana Class I TCP genes AtTCP7 and its roles in plant development
No full textPlant cell division cycle is a highly complex and tightly controlled process which is regulated by both cell cycle genes conserved across kingdoms and plant-specific regulators. TCP family genes are plant-specific transcription factors reported in recent years that function in many aspects of plant growth, and broadly control the morphology of different organs via positive or negative regulating target genes expression. The initial work in our study was to identify the transcriptional factors regulating miRNA168a gene expression. A TCP family gene AtTCP7 was isolated as a putative regulator of Arabidopsis miR168a from yeast one-hybrid screening. Transgenic plants over-expressing AtTCP7 gene in Arabidopsis thaliana showed a decrease of mature miRNA168a accumulation, while later crossing analysis co-expressing 35S::AtTCP7 and pMiR168a::GUS showed a minor affection on reporter gene GUS expression, it indicated that the AtTCP7 may not directly interact with miR168a promoter in vivo. In-depth phenotypic characterization of the transgenic lines displayed a variety of growth defects and developmental delay, including shorter roots, delayed flowering and reduced fertility. Analyses at different developmental stages demonstrated that over-expression of AtTCP7 differentially affected cell size and DNA content in different organs by altering cell cycle genes expression and by restricting the interphase transition from G1 to S phase. Further expression analyses on over-expressing lines uncovered a complex network of genetic interactions between the members of the TCP family, highlighting the functional interaction especially between TCP7 and TCP23
RNA-based therapeutic approaches for FTDP-17
No full textNeurodegenerative diseases are linked to altered splicing mechanisms (Mills et al., 2012). Fronto temporal dementia and parkinsonism linked to chromosome 17 (FTDP-17) is one such disease that stems from the differential splicing caused due to mutations in Microtubule associated protein tau (MAPT) gene (Esther et al., 2002).
This PhD thesis focuses on developing RNA-based therapeutic approaches to address FTDP-17.
CHAPTER 1 introduces a broad range of topics such as splicing mechanism, neurodegenerative diseases associated with splice defects, therapeutic tools to modulate such splice defects in the context of neurogenetic diseases and possible applications of available tools for FTDP-17.
CHAPTER 2 explores an exon skipping strategy to modulate splice defects in the context of FTD-17 using small nuclear RNAs (snRNAs).
CHAPTER 3 is based on a short interfering RNA (siRNA) approach to modulate post-transcriptional gene silencing of specific isoform associated to FTDP-17.
CHAPTER 4 employs long non coding RNA (lncRNA) to mediate post transcriptional repression of tau protein associated to FTDP-17 and deciphers its auxiliary role in splicing of exon 10
CHAPTER 5 elaborates on the future perspectives of all the above mentioned approaches to find a cure for FTDP-17
La scultura a Genova tra XV e XVI secolo. Artisti, cantieri e committenti
No full textLa tesi si concentra sull'analisi dello sviluppo della scultura a Genova in un arco cronologico compreso tra il 1466, anno che diede avviò ad un più stretto controllo da parte del Ducato di Milano sui territori della Repubblica, e il 1528, che segnò l'affermazione di Andrea Doria e il passaggio nell'orbita spagnola. In un simile contesto si è cercato di enucleare le peculiarità dell'ambiente genovese mettendo in luce da un lato i rapporti con aree limitrofe come la Lombardia e la Toscana e dall'altro l'autonomia rispetto a tali influenze. Nonostante l'origine anagrafica degli scultori attivi in città, il linguaggio elaborato a Genova presenta infatti caratteristiche specifiche.
Per analizzare una realtà così articolata si sono adottati più approcci metodologici, tenendo conto anche del rapporto con il contesto sociale e politico e delle dinamiche di committenza. All'analisi della documentazione nota e di quella emersa nel corso della ricerca si è accostata la lettura formale delle opere, allo scopo di dare una fisionomia distinta alle personalità attestate.
I primi due capitoli sono dedicati ai principali scultori attivi a Genova, mentre gli altri tre si concentrano su tematiche specifiche, ovvero un cantiere di primo piano come quello della Cattedrale di San Lorenzo, l'evoluzione della tipologia del monumento funerario e la fortuna dei marmi genovesi in Europa
Pre-stimulus oscillatory signatures of tactile detection and attention
No full textOscillatory neuronal activity in the alpha band has been associated with both conscious perception and attention. Firstly, conscious perception of a weak sensory stimulus is preceded by alpha power decreases. Secondly, attention to a sensory event reduces alpha activity in the corresponding sensory regions. According to the widely accepted functional inhibition hypothesis, oscillatory neural activity in the alpha band reflects cortical excitability; in other words, a sensory region with low alpha power levels is more excitable. Several questions regarding the relationship between conscious perception, attention and alpha band activity have not been addressed so far. Firstly, it remained unclear whether brain states predisposing consciousness only comprise local pre-stimulus alpha power decreases, or also global network states. Secondly, it remained unclear whether alpha power decreases prior to conscious perception are confounded by fluctuations of attention or not. The goal of the current thesis is to address these two open questions in the tactile modality with two magnetoencephalography studies.
The first study explored brain states predisposing conscious tactile perception, with a particular focus on functional connectivity patterns in addition to alpha power modulations. To this end, a simple near-threshold detection paradigm was conducted, with weak tactile stimuli to the participants’ left index finger. Findings revealed that conscious perception is preceded by a) a relative alpha power decreases in the somatosensory cortex contralateral to stimulation, and b) a spectrally specific pattern of functional connectivity in the primary somatosensory cortex. Based on the first study, it can be concluded that brain states predisposing consciousness comprise local cortical excitability changes as well as frequency-specific network patterns. The second study focused on alpha power changes prior to conscious perception in the context of spatial attention. To this end, a near-threshold detection paradigm with a double-pulse target stimulus was combined with a spatial attention task. The results showed a) that spatial tactile attention modulates pre-stimulus alpha power, and b) that spontaneous alpha power fluctuations not explained by attention influence perception. These findings indicate that – while attention does affect pre-stimulus alpha power levels – spontaneous alpha power fluctuations predispose consciousness. Taken together, we conclude that brain states predisposing conscious perception comprise spectrally specific functional connectivity patterns, and alpha power fluctuations distinct from attention-induced alpha power modulations
Binary quadratic forms, elliptic curves and Schoof's algorithm
No full textIn this thesis, I show that the representation of prime integers by reduced binary quadratic forms of given discriminant can be obtained in polynomial complexity using Schoof's algorithm for counting the number of points of elliptic curves over finite fields. It is a remarkable fact that, although an algorithm of Gauss' solved the representation problem long time ago, a solution in polynomial complexity is very recent and almost unnoticed in the literature. Further, I present a viable alternative to Gauss' algorithm, which constitutes the main original contribution of my thesis. This alternative way of computing in polynomial time an explicit solution of the representation problem is particularly suitable whenever the number of not equivalent reduced forms is small.
Lastly, I report that, in the efforts of improving Schoof's algorithm, a marginal incompleteness in its original formulation was identified. This weakness was eliminated by a slight modification of the algorithm suggested by Schoof himself
Development of new analytical techniques for chaotic time series
No full textIn the present thesis two main results are presented. The first is a study of the statistical properties of the finite-time maximum Lyapunov exponent determined out of a time series by using the divergent rate method. To reach this goal, we developed a new, completely automatic algorithm based on the method developed by Gao and Zheng. A main achievement of this part of the work is the interpretation of the uncertainty in the light of the work by Grassberger, Badii e Politi of 1988 on the theoretical distribution of maximum Lyapunov exponents. We showed that the analysis and identification of clusters in diagrams representing uncertainty vs. maximum Lyapunov exponent can provide useful information about the optimal choice of the embedding parameters. In addition, our results allow us to identify systems that can provide suitable benchmarks for the comparison and ranking of different embedding methods. The second main result concerns the development of a new method for the assessment of the optimal embedding parameters. Our method is based on two assumptions: a potential-like quantity is defined on the lattice of points that characterize the embedding; the optimal embedding choice coincides with local extrema (maxima or minima) of this potential. Throughout the work, we used "synthetic" time series generated by numerically integrating the difference and differential equations that describe the following dynamical systems: the Hénon map, the Lorenz attractor, the Rössler attractor and the Mackey-Glass attractor. These four systems are widely used as references in the scientific literature. In the last part of the work, we have started to examine EEG recordings by using the techniques developed in the main part of the work. The EEG recordings are sampled on healthy subjects in resting-state. These investigations are still at a starting phase
Empirical Essays on the Economics of Food Price Shocks: Micro-econometric Evidence from Uganda
No full textThis thesis contains four closely related essays which address the empirical issues pertaining to the causes, consequences, and households’ responses to food price shocks in Uganda. The first essay investigates the nature of volatilities in agricultural commodity prices in Uganda between 2000 and 2012 by focusing on six key food staples, namely matooke, cassava, maize, sweet potatoes, beans, and millet flour. It studies the behavior of monthly price volatilities of these commodities, examines the extent of their volatility spillovers, identifies their macroeconomic and environmental drivers, and uncover their differential impacts using respectively the General Autoregressive Conditional Heteroscedastic (GARCH), the Vector Autoregressive (VAR) and the Seemingly Unrelated Regression (SUR) models. I find evidence that both unconditional and conditional price volatilities have significantly increased since January 2008 for most commodities, period of turmoil in the global food markets. The GARCH (1, 1) estimates indicate a strong persistence in volatility for most commodities while results from the Exponential GARCH (1, 1) models suggest the presence of asymmetric and leverage effects of unexpected price shocks for half of the commodities. In addition, the VAR estimation results detect limited and mostly unidirectional spillover effects across food commodities. Finally, historical price volatilities of most commodities are found to be primarily affected by volatilities in consumer price indices, fuel prices, and rainfall, with less evidence of strong seasonality effects as previously reported. The second essay presents an empirical analysis of the welfare impacts of food price changes in Uganda using three waves of the Uganda National Panel Surveys (UNPS) spanning over the years 2005-2011. It theoretically investigates the implications of labor market imperfections and households’ heterogeneity in terms of their net positions in both food and labor markets and compares welfare estimates between separable and non-separable models. Through the estimations a panel stochastic production frontier function and a censored-Quadratic Almost Ideal Demand Systems (QUAIDS) with expenditure and shadow wage endogeneities, the results suggest that the welfare effects of price changes (measured in terms of compensating variations) were globally lower in the non-separable agricultural model, implying a high degree of labor market frictions. Furthermore, I find that the welfare effects were unevenly distributed both within and between household groups. Particularly, although agricultural households benefited from price increases as a group between 2005/6 and 2009/10, both significant and insignificant net buyers did suffer from price changes. Moreover, results from non-parametric estimations show that households at the extremes of the welfare distribution were more severely hit by food price instabilities than others. Finally, the essay suggests that the important dynamics in the net market positions observed during the sample period might be attributed to a cost-benefit analysis related to the potential welfare effects of food prices. The third essay explores the question of crop choices and land allocations in environments where farmers face uncertainties about end-of-season output prices and yield levels, weather variability, and formulate expectations about their future levels. Indeed, in the absence of credit and/or insurance markets, farmers are widely expected to adjust their land allocation decisions as a management tool against agricultural and market-related risks. However, little is actually known about the likely differential effects of each of these risk components on farmers’ decisions, particularly when current decisions are allowed to depend on previous choices. Using a nationally representative panel data set for agricultural households in Uganda spanning over the years 2005 – 2012, the paper proposes to investigate the role played by both price and yield risks on farmers’ crop choices and area allocations using a multivariate generalization of the Heckman-type two-step procedure: a multivariate crop selection and a conditional acreage share models. The crop selection problem is modeled as a dynamic multivariate probit regression and estimated through Simulated Maximum Likelihood and the Geweke Hajivassiliou Keane simulator, whereas the conditional acreage share model is estimated using a dynamic multivariate fractional logit model. In both the multivariate crop selection and acreage share models, the results reveal that, while own expected prices and yields are among the main drivers of farmers' crop choices and land share allocations, farmers are found to be more sensitive to changes in expected yield levels than in expected end-of-season output prices. In addition, yield risks, temperature and rainfall volatility appear to have more impact on acreage share decisions than market price risks. Finally, household characteristics are found to play a marginal role in explaining farmers’ crop selection and acreage allocation decisions. The fourth and last essay develops a modified standard Ramsey model to analyze households’ welfare growth and test the assumption that differential exposure to food price shocks leads to different welfare trajectories and to potentially increased risks of poverty traps. The essay focuses on two welfare indicators, namely consumption levels and asset indices, and employs a battery of econometric methods, ranging from parametric GMM fixed effects models to locally weighted scatterplot smoother (LOWESS), local polynomial regressions, and Ruppert et al’s (2003) semi-parametric penalized splines to address nonlinearities in welfare dynamics, identify and locate critical welfare thresholds, and test for the presence of single against multiple welfare equilibria. Using the full sample, I find nonlinearities in welfare dynamic paths and reduction in the growth rates of both consumption levels and assets holdings as a consequence of exposure to food price and asset shocks. However, there is no evidence of poverty traps caused by households’ exposure or vulnerability to food price shocks, but instead I identify only a single dynamic stable equilibrium, located slightly above the official poverty, towards which Ugandan households are converging in the long run. Finally, when disaggregating households into different sub-groups sharing similar characteristics, the empirical results reveal that Ugandan households are converging towards specific welfare equilibria, depending on their initial conditions, demographic characteristics, the extent of their vulnerability and differential exposure to food price shocks. Particularly, I found that, households exposed to food price shocks or above the vulnerability threshold index are expected to move in the long run to welfare equilibria located at lower levels than their unexposed or less vulnerable counterparts