14 research outputs found
Advances in Stochastic Duality for Interacting Particle Systems: from many to few
No full textInteracting particle systems (IPS) is a subfield of probability theory that provided a fruitful framework in which several questions of physical interests have been answered with mathematical rigor. An interacting particle system is a stochastic system consisting of a very large number of particles interacting with each other. The class of IPS considered in this manuscript is the one of systems satisfying stochastic duality. Stochastic duality is a useful tool in probability theory which allows to study a Markov process (the one that interests you) via another Markov process, called dual process, which is hopefully easier to be studied. The connection between the two processes is established via a function, the so-called duality function, which takes as input configurations of both processes. In the context of IPS, one of the typical simplifications provided by stochastic duality is that a system with an infinite number of particles can be studied via a finite number of particles (the simplification from many to few).In this thesis, we extend the theory and the applications of stochastic duality in the following two contexts:i) evolution of particles in space inhomogeneous settings and more precisely, processes in random environmentand processes in a multi-layer system;ii) evolutions of particles in the continuum.Applied Probabilit
Essays on Corruption
No full textCorruption is blamed for reductions in operational efficiency, information asymmetry, limited income distribution, policy failure, and weak economic growth and development. Corruption can originate from either the “demand-side” (the recipients of the bribe) or the “supply-side” (the givers of the bribe). This double edge effect of corruption on the economy and society makes it a multidisciplinary subject and phenomenon. Thus, scholars from different fields and disciplines, such as finance, banking, economics, accounting, law, foreign aid, and international business, examined and analyzed corruption as a multidisciplinary subject. In this dissertation, I investigate and explore the characteristics and association of corruption with firms, international business, banking, foreign direct investment (FDI), foreign aid, and international trade flows
Rising plasma nociceptin level during development of HCC: A case report
No full textAIM: Although liver cirrhosis is a predisposing factor for hepatocellular carcinoma (HCC), relatively few reports are available on HCC in primary biliary cirrhosis. High plasma nociceptin (N/OFQ) level has been shown in Wilson disease and in patients with acute and chronic pain.
METHODS: We report a follow-up case of HCC, which developed in a patient with primary biliary cirrhosis. The tumor appeared 18 years after the diagnosis of PBC and led to death within two years. Alfa fetoprotein and serum nociceptin levels were monitored before and during the development of HCC. Nociceptin content was also measured in the tumor tissue.
RESULTS: The importance and the curiosity of the presented case was the novel finding of the progressive elevation of plasma nociceptin level up to 17-fold (172 pg/mL) above the baseline (9.2 +/- 1.8 pg/mL) parallel with the elevation of alpha fetoprotein (from 13 ng/mL up to 3 480 ng/mL) during tumor development. Nociceptin content was more than 15-fold higher in the neoplastic tissue (0.16 pg/mg) than that in the tumor-free liver tissue samples (0.01 pg/mg) taken during the autopsy.
CONCLUSION: Results are in concordance with our previous observation that a very high plasma nociceptin level may be considered as an indicator for hepatocellular carcinoma
Hydrodynamics for the partial exclusion process in random environment
No full textIn this paper, we introduce a random environment for the exclusion process in Zd obtained by assigning a maximal occupancy to each site. This maximal occupancy is allowed to randomly vary among sites, and partial exclusion occurs. Under the assumption of ergodicity under translation and uniform ellipticity of the environment, we derive a quenched hydrodynamic limit in path space by strengthening the mild solution approach initiated in Nagy (2002) and Faggionato (2007). To this purpose, we prove, employing the technology developed for the random conductance model, a homogenization result in the form of an arbitrary starting point quenched invariance principle for a single particle in the same environment, which is a result of independent interest. The self-duality property of the partial exclusion process allows us to transfer this homogenization result to the particle system and, then, apply the tightness criterion in Redig et al. (2020).Applied Probabilit
Hydrodynamic Limit for the Symmetric Inclusion Process with Slowly Varying Inhomogeneities
No full textIn this thesis we study an interacting particle system: the Symmetric Inclusion Process with slowly varying inhomogeneities (SIP(α)). In the SIP(α) particles display random walk like behaviour subjected to an attractive type of interaction whilst evolving in an inhomogeneous environment. We set out to prove its hydrodynamic limit. The main tool helping us for obtaining the hydrodynamic limit is the self-duality property of the process.Applied Mathematic
Switching Interacting Particle Systems: Scaling Limits, Uphill Diffusion and Boundary Layer
No full textThis paper considers three classes of interacting particle systems on Z: independent random walks, the exclusion process, and the inclusion process. Particles are allowed to switch their jump rate (the rate identifies the type of particle) between 1 (fast particles) and ϵ∈ [0 , 1] (slow particles). The switch between the two jump rates happens at rate γ∈ (0 , ∞). In the exclusion process, the interaction is such that each site can be occupied by at most one particle of each type. In the inclusion process, the interaction takes places between particles of the same type at different sites and between particles of different type at the same site. We derive the macroscopic limit equations for the three systems, obtained after scaling space by N- 1, time by N2, the switching rate by N- 2, and letting N→ ∞. The limit equations for the macroscopic densities associated to the fast and slow particles is the well-studied double diffusivity model. This system of reaction-diffusion equations was introduced to model polycrystal diffusion and dislocation pipe diffusion, with the goal to overcome the limitations imposed by Fick’s law. In order to investigate the microscopic out-of-equilibrium properties, we analyse the system on [N] = { 1 , … , N} , adding boundary reservoirs at sites 1 and N of fast and slow particles, respectively. Inside [N] particles move as before, but now particles are injected and absorbed at sites 1 and N with prescribed rates that depend on the particle type. We compute the steady-state density profile and the steady-state current. It turns out that uphill diffusion is possible, i.e., the total flow can be in the direction of increasing total density. This phenomenon, which cannot occur in a single-type particle system, is a violation of Fick’s law made possible by the switching between types. We rescale the microscopic steady-state density profile and steady-state current and obtain the steady-state solution of a boundary-value problem for the double diffusivity model.Applied Probabilit
Managing large corporate crisis in Italy: an empirical survey on extraordinary adminstration
No full textExtraordinary Administration (amministrazione straordinaria), a sort of Italian Chapter 11, was introduced into Italian bankruptcy legislation in 1979, in order to manage large corporate crises. Differently from other Italian bankruptcy procedures, Extraordinary Administration is a sort of hybrid since it is under the jurisdiction of both the administrative authority (Ministry of Industry) as well as the Court. Currently there are two distinct phases. During the initial “observation” phase, the company is managed by an extraordinary administrator who has to verify if there is a real possibility for restructuring. According to the restructuring program, prepared by the administrator, in the second phase the company, following a going concern logic, can either be sold to other investors or guided towards a stand alone recovery. As often happens with bankruptcy laws, there is ample theoretical framework and a very large number of studies have been carried out, focused on the legal aspects (for a general overview in English see Panzani, 2009) while economic issues have not been thoroughly investigated. Among the few we refer to Floreani,1997; Leogrande, 2003; Danovi, 2003; Falini 2008. In such a context, this paper aims at presenting some initial empirical evidence regarding how the procedure was put into effect between 1999 (the year of the reform) and 2008. Sources of information are documents available from the Ministry of Industry, which sets out the procedure and has to approve the restructuring plan and the Court Houses that are empowered to accept filing for Extraordinary Administration, in cases of insolvency. The data collected, regarding almost all cases ruled by Act 270/1999 refer to 65 groups composed by 313 companies. The paper investigates: i) the economic relevance of the phenomenon; ii) the characteristics and assets of the companies involved; iii) timeframes and management aspects; iv) safeguarding of the work force. The author is aware that because of the statistical limits the analysis can be considered an initial survey, but it is worth presenting as the basis for future studies and to create the conditions for proper discussion for an institution whose real weight is often merely imagined, rather than known
Real-world experience with obeticholic acid in patients with primary biliary cholangitis
No full textBackground & aims: Obeticholic acid (OCA) is the second-line treatment approved for patients with primary biliary cholangitis (PBC) and an inadequate response or intolerance to ursodeoxycholic acid. We aimed to evaluate the effectiveness and safety of OCA under real-world conditions.Methods: Patients were recruited into the Italian PBC Registry, a multicentre, observational cohort study that monitors patients with PBC at national level. The primary endpoint was the biochemical response according to Poise criteria; the secondary endpoint was the biochemical response according to normal range criteria, defined as normal levels of bilirubin, alkaline phosphatase (ALP), and alanine aminotransferase (ALT) at 12 months. Safety and tolerability were also assessed.Results: We analysed 191 patients until at least 12 months of follow-up. Median age was 57 years, 94% female, 61 (32%) had cirrhosis, 28 (15%) had histologically proven overlap with autoimmune hepatitis (PBC-AIH). At 12 months, significant median reductions of ALP (-32.3%), ALT (-31.4%), and bilirubin (-11.2%) were observed. Response rates were 42.9% according to Poise criteria, and 11% by normal range criteria. Patients with cirrhosis had lower response than patients without cirrhosis (29.5% vs. 49.2%, p = 0.01), owing to a higher rate of OCA discontinuation (30% vs. 12%, p = 0.004), although with similar ALP reduction (29.4% vs. 34%, p = 0.53). Overlap PBC-AIH had a similar response to pure PBC (46.4% vs. 42.3%, p = 0.68), with higher ALT reduction at 6 months (-38% vs. -29%, p = 0.04). Thirty-three patients (17%) prematurely discontinued OCA because of adverse events, of whom 11 experienced serious adverse events. Treatment-induced pruritus was the leading cause of OCA discontinuation (67%).Conclusions: Effectiveness and safety of OCA under real-world conditions mirror those in the Poise trial. Patients with cirrhosis had lower tolerability. Overlap PBC-AIH showed higher ALT reduction at 6 months compared with patients with pure PBC.Lay summary: Obeticholic acid (OCA) was shown to be effective in more than one-third of patients not responding to ursodeoxycholic acid in a real-world context in Italy. Patients with cirrhosis had more side effects with OCA, and this led to suspension of the drug in one-third of patients. OCA was also effective in patients who had overlap between autoimmune hepatitis and primary biliary cholangitis. (C) 2021 The Author(s). Published by Elsevier B.V. on behalf of European Association for the Study of the Liver (EASL)
Corrigendum to ‘An international genome-wide meta-analysis of primary biliary cholangitis: Novel risk loci and candidate drugs’ [J Hepatol 2021;75(3):572–581]
No full text\ua9 2021It has come to our attention that the name of one of the authors in our manuscript was incorrectly spelled ‘Jinyoung Byan’; the correct spelling is ‘Jinyoung Byun’ as in the author list above. In addition, the excel files of the supplementary tables were not included during the online publication of our article. These have now been made available online. We apologize for any inconvenience caused
