A Bayesian framework for functional time series analysis

The paper introduces a general framework for statistical analysis of functional time series from a Bayesian perspective. The proposed approach, based on an extension of the popular dynamic linear model to Banach-space valued observations and states, is very flexible but also easy to implement in many cases. For many kinds of data, such as continuous functions, we show how the general theory of stochastic processes provides a convenient tool to specify priors and transition probabilities of the model. Finally, we show how standard Markov chain Monte Carlo methods for posterior simulation can be employed under consistent discretizations of the data

An R Package for Dynamic Linear Models

We describe an R package focused on Bayesian analysis of dynamic linear models. The main features of the package are its flexibility to deal with a variety of constant or time-varying, univariate or multivariate models, and the numerically stable singular value decomposition-based algorithms used for filtering and smoothing. In addition to the examples of "out-of-the-box" use, we illustrate how the package can be used in advanced applications to implement a Gibbs sampler for a user-specified model.

State Space Models in R

We give an overview of some of the software tools available in R, either as built- in functions or contributed packages, for the analysis of state space models. Several illustrative examples are included, covering constant and time-varying models for both univariate and multivariate time series. Maximum likelihood and Bayesian methods to obtain parameter estimates are considered.

An R Package for Dynamic Linear Models

We describe an <b>R</b> package focused on Bayesian analysis of dynamic linear models. The main features of the package are its flexibility to deal with a variety of constant or time-varying, univariate or multivariate models, and the numerically stable singular value decomposition-based algorithms used for filtering and smoothing. In addition to the examples of "out-of-the-box" use, we illustrate how the package can be used in advanced applications to implement a Gibbs sampler for a user-specified model

Physics and modelling of generation and propagation of noise by complex sources in realistic basins

The need to develop more accurate numerical tools for the propagation of noise in underwater environments is driven by the continuous increase of human activity in the sea and coastal areas. Noise has been shown to be dangerous to marine wildlife, and steps should be taken soon to mitigate it. Knowing that the primary sources of noise pollution at sea are marine propellers, one of the problems is assessing how the noise generated interacts with the environment, since up to now, the main focus was the characterization of the acoustic signature in the near field or, alternatively, the propagation of simplified acoustic sources in sea-like domains. The work conducted in this thesis assesses the modelling of complex acoustic sources and the propagation of acoustic pressure in realistic domains. A propagation model based on the solution of the acoustic wave equation in the time and space domain is implemented and used in conjunction with the Ffowcs Williams and Hawkings (FW-H) to analyze the possible patterns occurring in the underwater environment. Specifically, we analyzed the noise radiated by a marine propeller in a canal, focusing on the effects of the boundaries on the acoustic field and, secondly, the consequence of a rotating body placed underneath a free surface. We defined a new methodology called Full Acoustic Analogy (FAA) to achieve these results. This methodology aims to overcome some intrinsic limitations of the known Acoustic Analogies. The study presented here attempts to bridge the gap between noise characterization and its propagation by introducing a new methodology for evaluating flow-induced noise in a realistic environment. The propagation model developed, which used the finite-difference-time-domain method, has been compared against benchmark cases (monopole source propagating in classical waveguides) for which an analytical solution is available, and it provides accurate results of the acoustic field. Furthermore, a second analysis is conducted on two classical waveguides: the Ideal one and the Pekeris one. The solution of the wave equation in time and physical space enables the implementation of different sources, such as dipole and quadrupole; therefore, we analyzed the acoustic response of the Pekeris waveguide. The results show that the propagation of the acoustic pressure is strongly affected by the directivity pattern of the source. This was the first step in evaluating the capabilities of the solution of the acoustic equation in the presence of sources characterized by complex directivity since our ultimate goal is to evaluate the noise emitted by a propeller. In the second part, the FAA analogy is introduced, and we describe how the acoustic pressure obtained with the FW-H equation is used as a source term in the propagation model. After the validation of the new proposed methodology in an unbounded homogeneous domain, we investigate the propagation of the linear part of the noise generated by a naval propeller within a canal. Local maxima and minima of the acoustic fields arise from the interaction between the noise source and the environment; in particular, they derive from the superposition of direct and reflected waves. Moreover, a rotating body placed underneath a free surface generates a peculiar asymmetry of the acoustic field associated with the interaction between the acoustic waves and the free surface.The need to develop more accurate numerical tools for the propagation of noise in underwater environments is driven by the continuous increase of human activity in the sea and coastal areas. Noise has been shown to be dangerous to marine wildlife, and steps should be taken soon to mitigate it. Knowing that the primary sources of noise pollution at sea are marine propellers, one of the problems is assessing how the noise generated interacts with the environment, since up to now, the main focus was the characterization of the acoustic signature in the near field or, alternatively, the propagation of simplified acoustic sources in sea-like domains. The work conducted in this thesis assesses the modelling of complex acoustic sources and the propagation of acoustic pressure in realistic domains. A propagation model based on the solution of the acoustic wave equation in the time and space domain is implemented and used in conjunction with the Ffowcs Williams and Hawkings (FW-H) to analyze the possible patterns occurring in the underwater environment. Specifically, we analyzed the noise radiated by a marine propeller in a canal, focusing on the effects of the boundaries on the acoustic field and, secondly, the consequence of a rotating body placed underneath a free surface. We defined a new methodology called Full Acoustic Analogy (FAA) to achieve these results. This methodology aims to overcome some intrinsic limitations of the known Acoustic Analogies. The study presented here attempts to bridge the gap between noise characterization and its propagation by introducing a new methodology for evaluating flow-induced noise in a realistic environment. The propagation model developed, which used the finite-difference-time-domain method, has been compared against benchmark cases (monopole source propagating in classical waveguides) for which an analytical solution is available, and it provides accurate results of the acoustic field. Furthermore, a second analysis is conducted on two classical waveguides: the Ideal one and the Pekeris one. The solution of the wave equation in time and physical space enables the implementation of different sources, such as dipole and quadrupole; therefore, we analyzed the acoustic response of the Pekeris waveguide. The results show that the propagation of the acoustic pressure is strongly affected by the directivity pattern of the source. This was the first step in evaluating the capabilities of the solution of the acoustic equation in the presence of sources characterized by complex directivity since our ultimate goal is to evaluate the noise emitted by a propeller. In the second part, the FAA analogy is introduced, and we describe how the acoustic pressure obtained with the FW-H equation is used as a source term in the propagation model. After the validation of the new proposed methodology in an unbounded homogeneous domain, we investigate the propagation of the linear part of the noise generated by a naval propeller within a canal. Local maxima and minima of the acoustic fields arise from the interaction between the noise source and the environment; in particular, they derive from the superposition of direct and reflected waves. Moreover, a rotating body placed underneath a free surface generates a peculiar asymmetry of the acoustic field associated with the interaction between the acoustic waves and the free surface

Full Acoustic Analogy of the fluid-dynamics noise of an immersed cube

The estimation of fluid dynamic noise generated by anthropogenic sources in realistic marine basins and on land is paramount for human safety and environmental protection. Classical acoustic analogies have limited capabilities when considering the natural variability and peculiarities of the acoustic propagation domain. The Full Acoustic Analogy (FAA), based on the combination of an acoustic analogy for source characterization and a propagation model for far-field transmission, allows the estimation of detailed soundmaps, practical when assessing the risk associated with exposure to fluid-dynamic noise, both impulsive and continuous. The verification of the methodology, consisting of comparing of the far-field acoustic pressure signal obtained with the FAA and with the Ffowcs-Williams and Hawkings equation (classical acoustic analogy for moving immersed bodies), is proven for the first time for the quadrupole non-linear terms. The latter may contribute significantly to the total noise field at small-to-medium distances from the source. In conjunction, the ability of the FAA method to predict the acoustic pressure distribution within the three-dimensional propagation domain is highlighted

Kriging for Hilbert-space valued random fields: the Operatorial point of view

open2siembargoed_20190616Menafoglio, Alessandra; Petris, GiovanniMenafoglio, Alessandra; Petris, Giovann

Detection of Intratumor Heterogeneity in Modern Pathology: A Multisite Tumor Sampling Perspective

Current sampling protocols of neoplasms along the digestive tract and in the urinary bladder have to be updated, as they do not respond to the necessities of modern personalized medicine. We show here that an adapted version of multisite tumor sampling (MSTS) is a sustainable model to overcome current deficiencies in digestive and bladder tumors when they are large enough so as to make unaffordable a total sampling. The new method is based on the divide-and-conquer algorithm and includes a slight modification of the MSTS, which proved to be useful very recently in clear cell renal cell carcinoma. This in silico analysis confirms the usefulness of MSTS for detecting intratumor heterogeneity (ITH) in tumors arising in hollow viscera. However, MSTS does not seem to improve routine traditional sampling in detecting tumor budding, extramural venous invasion, and perineural invasion. We conclude that (1) MSTS is the best method for tumor sampling to detect ITH balancing high performance and sustainable cost, (2) MSTS must be adapted to tumor shape and tumor location for an optimal performance.JC acknowledges financial support from Ikerbasque: The Basque Foundation for Science. This work was partially funded by grant SAF2013-48812-R from Ministerio de Economia y Competitividad (Spain) to JL; grant DPI2016-79874-R from Ministerio Economia y Competitividad (Spain) and FEDER to JC

The Association of Ménétrier Disease with Ulcerative Colitis: A Case Report with Implications on the Pathogenesis of Ménétrier Disease

Ménétrier disease (MD) is a rare hypertrophic condition of the gastric mucosa. The unusual association of MD with ulcerative colitis (UC) has been reported in the literature in eight cases. Transforming growth factor-alpha (TGF-alpha) is overexpressed in UC and appears to play a role in colonic healing and repair. Overproduction of TGF-alpha in murine stomach has been shown to induce gastric hypertrophy similar to MD. It can be hypothesized that increased expression of TGF-alpha may occur in the gastric mucosa in patients with UC and may lead to MD. We report the ninth case of MD associated with UC. The role of TGF-alpha and treatment with cetuximab are discussed

Shiga Toxin–Producing Escherichia coli Infections Associated with Hemolytic Uremic Syndrome, Italy, 1988–2000

The mean annual incidence of hemolytic uremic syndrome in persons <15 years of age in Italy from 1988 to 2000 was 0.28 per 100,000 population. Laboratory investigations showed that Shiga toxin–producing Escherichia coli (STEC) infection occurred in 73.1% of patients. STEC O157 was the most common serotype, but a considerable number of cases were from infections by non-O157 STEC