Singular p-Laplacian parabolic system in exterior domains: higher regularity of solutions and related properties of extinction and asymptotic behavior in time

We consider the IBVP in exterior domains for the p-Laplacian parabolic system. We prove regularity up to the boundary, extinction properties for p \in ( 2n/(n+2) , 2n/(n+1) ) and exponential decay for p= 2n/(n+1)

Carceri e Stranieri.

The issue of foreign national prisoners needs to be considered in a national and supranational perspective because of its importance, related to different topics connected to the respect of the rights of the foreign inmate. Among these, we have to keep in special consideration the exposure to discrimination, the lack of access to justice (due inter alia to the language barrier), the relational isolation, the difficult reintegration and the impact of the status of illegal immigrant. Facing such a view, it’s easy to understand the central importance of all the international instruments for the protection of foreign prisoners, especially of the European framework decisions, unfortunately non totally applied in each Member State. Their particular importance is due to the fact that, if correctly implemented, they can have a strong impact on different phenomena, such as the diminution of the foreign prisoners and their effective reintegration, thanks to the mutual recognition to criminal decision and the possibility to transfer persons deprived of liberty. However, different kind of reasons may hinder the fully application of these framework decisions. So, from one hand, their implementation needs efforts from each Member State, from the other one, the national governments should consider the possibility to identify privileged interlocutors for the approval of convention that can allow the transfer of stakeholders.La tematica dei detenuti stranieri, connotata da una speciale rilevanza sia se considerata a livello nazionale sia a livello sovranazionale, solleva tutta una serie di questioni connesse al rispetto dei diritti delle persone che si trovano a scontare una pena in un Paese diverso da quello di origine. Tra queste, spiccano quella dell’esposizione alla discriminazione, delle difficoltà di accesso alla giustizia (dovuto fra l’altro alle barriere linguistiche), dell’isolamento relazionale, del reinserimento e dell’impatto dello status di clandestino. Dinanzi a siffatto panorama, assumono importanza centrale gli strumenti internazionali a tutela dei detenuti stranieri: particolare riguardo verrà riservato alle decisioni-quadro europee, strumenti dall’alto potenziale, ma non ancora compiutamente applicati in tutti gli Stati Membri. Tra i fenomeni su cui potrebbero impattare figurano, da un lato, quello del mutuo riconoscimento delle sentenze penali e, dall’altro, quello del trasferimento dei detenuti, delle persone in misura alternativa e dei reclusi in forza di un provvedimento cautelare: la loro corretta applicazione permetterebbe dunque un decremento degli stranieri reclusi e al contempo la possibilità di un loro reinserimento nel contesto di appartenenza. Tuttavia, ragioni ideologiche, teoriche e legislative, possono ostacolare l’applicazione delle decisioni-quadro, così che, se da un lato si rende necessario il loro recepimento all’interno dei singoli ordinamenti degli Stati Membri, dall’altro si ritiene di fondamentale importanza l’individuazione, da parte delle realtà nazionali, di quei Paesi che potrebbero rappresentare gli interlocutori privilegiati di percorsi di trasferimento che possano essere intrapresi dai soggetti interessati

On the plane steady-state flow of a shear-thinning liquid past an obstacle in the singular case

We show existence of strong solutions to the steady-state, two-dimensional exterior problem for a class of shear-thinning liquids –where shear viscosity is a suitable decreasing function of shear rate– for data of arbitrary size. Notice that the analogous problem is, to date, open for liquids governed by the Navier-Stokes equations, where viscosity is constant. Two important features of this work are that, on the one hand and unlike previous contributions by the same authors, the current results do not require non-vanishing of the constant-viscosity part of the stress tensor, and, on the other hand, we allow the shear-thinning contribution to be “arbitrarily small”, and, therefore, the model used here can be as “close” as we please to the classical Navier-Stokes one

Womersley flow of generalized Newtonian liquid

We show that in an infinite straight pipe of arbitrary (sufficiently smooth) cross-section, a generalized non-Newtonian liquid admits one and only one fully developed time-periodic flow (Womersley flow) when either the flow rate (problem 1) or the axial pressure gradient (problem 2) is prescribed in analogous time-periodic fashion. In addition, we show that the relevant solution depends continuously upon the data in appropriate norms. As is well known from the Newtonian counterpart of the problem, the latter is pivotal for the analysis of flow in a general unbounded pipe system with cylindrical outlets (Leray's problem). It is also worth remarking that problem 1 possesses an intrinsic interest from both mathematical and physical viewpoints, in that it constitutes a (nonlinear) inverse problem with a significant bearing on several applications, including blood flow modelling in large arteries

Monitoring clumpy wind accretion in supergiant fast X-ray transients with XMM-Newto

Supergiant fast X-ray transients (SFXTs) are a sub-class of supergiant high mass X-ray binaries hosting a neutron star accreting from the stellar wind of a massive OB companion. Compared to the classical systems, SFXTs display a pronounced variability in X-rays that has long been (at least partly) ascribed to the presence of clumps in the stellar wind. We report here on the first set of results of an on-going XMM-Newton observational program aimed at searching for spectroscopic variability during the X-ray flares and outbursts of the SFXTs. The goal of the paper is to present the observational program and show that the obtained results are according to expectations, with a number of flares (between one and four) generally observed per source and per observation (20~ks-long, on average). We base our work on a systematic and uniform analysis method optimized to consistently search for spectral signatures of a variable absorption column density, as well as other parameters of the spectral continuum. Our preliminary results show that the program is successful and the outcomes of the analysis support previous findings that most of the X-ray flares seem associated to the presence of a massive structure approaching and getting accreted by the compact object. However, we cannot rule out that other mechanisms are at work together with clumps to enhance the X-ray variability of SFXTs. This is expected according to current theoretical models. The success of these observations shows that our observational program can be a powerful instrument to deepen our understanding of the X-ray variability in SFXTs. Further observations will help us in achieving a statistically robust sample. This is required to conduct, in the future, a systematic analysis on the whole SFXT class with the ultimate goal of disentangling the role of different mechanisms giving rise to these events.Comment: Accepted for publication on A&

The present and future of sustainability disclosure in equity investment funds’ pre-contractual documents: Mapping ESG discourse through STM

To show how pre-contractual documents are currently employed to disclose sustainability and ESG-related information, we map and examine the contents of 945 Key Investor Information Documents (KIIDs) from ten major asset managers, including sustainable and non-sustainable funds. Through a Structural Topic Modelling approach, we infer sustainability-related topics and compare their contents and prevalence in different sections of these documents. Sustainability is a cross-cutting and multifaceted issue, discussed coherently with the SFDR fund classification across multiple sections of the KIID, making the option to convey sustainable information in a single section complex to implement

Visualizing and comparing distributions with half-disk density strips

We propose a user-friendly graphical tool, the half-disk density strip (HDDS), for visualizing and comparing probability density functions. The HDDS exploits color shading for representing a distribution in an intuitive way. In univariate settings, the half-disk density strip allows to immediately discern the key characteristics of a density, such as symmetry, dispersion, and multi-modality. In the multivariate settings, we define HDDS tables to generalize the concept of contingency tables. It is an array of half-disk density strips, which compactly displays the univariate marginal and conditional densities of a variable of interest, together with the joint and marginal densities of the conditioning variables. Moreover, HDDSs are by construction well suited to easily compare pairs of densities. To highlight the concrete benefits of the proposed methods, we show how to use HDDSs for analyzing income distribution and life-satisfaction, conditionally on continuous and categorical controls, from survey data. The code for implementing HDDS methods is made available through a dedicated R package