448 research outputs found
'networks' and 'cohesion' as planning values: notes on the Pla Territorial General de CAtalunya and the 'Pla Estrategic Barcelona 2000'.
No full textA survey of parallel direct methods for block bidiagonal linear systems on distributed memory computers
No full textAbstractFour parallel algorithms for the solution of block bidiagonal linear systems on distributed memory computers are presented. All the algorithms belong to the class of direct methods. The first is a variant of the sequential algorithm and is suitable for a small number of processors. The remaining three algorithms are based on the parallel methods for banded systems and are much better suited for parallel computations on multiple processors. The arithmetical complexity functions of the proposed algorithms are derived. The results of experiments with the four algorithms implemented in Parallel Fortran on a linear array of 32 Transputers are presented and discussed
Italian Experience
No full textAutoimmune pancreatitis (AIP) is now a well-defined disease of the pancreas that differs clinically, radiologically, and therapeutically from all the other inflammatory diseases of the pancreas. It has been recently histologically classified in type 1 and type 2 AIPs, not different at imaging, but with a better clinical outcome in type 2 compared to type 1. From a clinical point of view, the key point in Italy is to differentiate focal form of the disease from pancreatic cancer. The Italian diagnostic algorithm is therefore addressed to exclude cancer in this setting and, therefore, to safely use steroids. In diffuse form of the disease, the clinical problem is to differentiate AIP from acute nonnecrotizing pancreatitis and to exclude neoplasia (cholangiocarcinoma or lymphoma) in some cases. In this chapter, we report the clinical profile of an Italian series of patients with AIP and highlight the main radiological and pathological findings
The emerging role of follicular CD4 T cells in the immune system: a comprehensive analysis in different diseases and anatomic compartment in the era of Covid19
No full textT follicular helper cells (TFH) are specialized subset of CD4 + T cells essential for the proper generation of germinal center (GC) reaction which eventually lead to the development of antigen specific memory B cell upon antigen stimulation. The present dissertation will perform a comprehensive analysis of the emerging role of TFH in the immune system analyzing their role in different diseases and anatomic compartment with a focus on SARS-CoV2. Only few studies in humans were able to provide a discrete description of the complex network of cytokines, chemokines and lymphocytes acting in tissues after antigenic challenge since most data derive from animal models. A better understanding of the biology of human immune system within tissues, where the actual immune responses take place, is mandatory to fill the gap of knowledge between animal and human models and to gain more insight into the basic immunology. I report published results of TFH analysis performed across the PhD course, starting with the analysis of mucosal immune dynamics in tonsils investigating the spatial positioning, frequency, and phenotype of immune cells after vaccination. Next, the increasing evidence of the active role of TFH also in the context of immunodeficiencies led us to further investigate their role in such condition. In this context I report a detailed immunophenotyped 6 analysis of children affected by Chromosome 22q11.2 deletion syndrome. Finally the emergence of SARS-Cov2 pandemic pushed the scientific community and ourselves in concentrating the efforts to dissecting the pathogenesis of this disease. I report the results of an important study about the immunology of Multisystem Inflammatory Syndrome in Children with COVID-1
Whispering gallery modes in oblate spheroidal cavities: calculations with a variable stepsize
No full textWe propose an efficient and reliable technique to calculate highly localized Whispering Gallery Modes (WGMs) inside an oblate spheroidal cavity. The idea is to first separate variables in spheroidal coordinates and then to deal with two ODEs, related to the angular and radial coordinates solved using high order finite difference schemes. It turns out that, due to solution structure, the efficiency of the calculation is greatly enhanced by using variable stepsizes to better reflect the behaviour of the evaluated functions. We illustrate the approach by numerical experiments
Thermo-structural analysis of components in ceramic material
No full textThe aim of this paper is the systematic study of thermo-structural behavior of ceramic components, in particular, mixtures of refractory materials with high thermal and mechanical performance. Using 3-point bending tests, the elastic modulus, ultimate stress and elongation was obtained; measured values, also thanks to the use of DIC optical technology, was correlated with the different thickness and specific weight values of the specimens used. In order to characterize the thermal behavior, thermal conductivity and specific heat were measured. The experimentally determined average values of such thermomechanical properties have been used in FEM thermo-mechanical models, developed using target geometries with shapes and sizes typical of manufactured ceramic products. In order to evaluate the goodness and the correctness of the developed models, some specimens having the the same shape of the target geometries used in FEM models have been tested at different load conditions and constraints
Palaeoenvironment and palaeoecology before and at the onset of Oceanic Anoxic Event (OAE)1a: Reconstructions from Central Tethyan archives
No full textIn this study, a new C-isotope stratigraphy combined with a revised litho-and biostratigraphy of Barremian-Aptian platform carbonates from the central-southern Apennines (Italy) is presented. The Santa Maria (Abruzzi Region) and the Monte Faito (Campania Region) sections were investigated in order to trace platform evolution during a time of major C-cycle perturbation before and during Oceanic Anoxic Event (OAE)1a. These successions are correlated at a regional scale with the Monte Raggeto reference section (Campania) where the Selli Level Equivalent (SLE) and the Magnetic Polarity Chron CM0r were recognised in earlier studies. Significant biotic and environmental changes are documented within the Late Barremian-Early Aptian interval; in particular, the Palorbitolina lenticularis-Lithocodium-Bacinella association followed by dark-brown microbial sediments reflect considerable ecological stress upon the oligotrophic carbonate platform community (mesotrophic or even eutrophic conditions) which precedes the onset of SLE by at least 1.2 myr. Moreover, this integrated approach has resulted in an improved age control which offers the opportunity to correlate the Apenninic sections with a succession from the French Urgonian platform (Cluses section) and with pelagic records from the Italian Umbria-Marche (Gorgo a Cerbara) and Belluno (Cismon Apticore) Basins. Pelagic biozonations and magnetostratigraphy have been projected into carbonate platform sequences. A prevailing eustatic origin has been attributed to some of the lower-frequency transgressive-regressive cycles (T/RFTs) that reflect third order sea-level oscillations. The new correlations indicate that comparable biotic and environmental changes, documented around the Tethys, are not always synchronous. The type of response of biota to C-cycle perturbations before and during OAE1a depends upon palaeolatitude, palaeogeography, palaeobathymetry and regional climate patterns
Numerical simulation of the whispering gallery modes in prolate spheroids
No full textIn this paper, we discuss the progress in the numerical simulation of the so-called `whispering gallery' modes (WGMs) occurring inside a prolate sphero\-idal cavity. These modes are mainly concentrated in a narrow domain along the equatorial line of a spheroid and they are famous because of their extremely high quality factor.
The scalar Helmholtz equation provides a sufficient accuracy for WGM simulation and (in a contrary to its vector version) is separable in spheroidal coordinates.
However, the numerical simulation of `whispering gallery' phenomena is not straightforward. The separation of variables yields two spheroidal wave ordinary differential equations (ODEs), first only depending on the angular, second on the radial coordinate. Though separated, these equations remain coupled through the separation constant and the eigenfrequency, so that together with the boundary conditions they form a singular self-adjoint two-parameter Sturm--Liouville problem.
We discuss an efficient and reliable technique for the numerical solution of this problem which enables calculation of highly localized WGMs inside a spheroid. The presented approach is also applicable to other separable geometries. We illustrate the performance of the method by means of numerical experiments
Phthalates in foods
No full textPhthalates are chemicals known mainly as plasticizers in the polymer industry, with worldwide extensive industrial application, that have caused widespread environmental pollution. This chapter describes the main sources of human exposure to phthalates; human health effects and the approach and methods to exposure assessment; the sources of food contamination during agricultural production, processing and packaging; data on occurrence in food and on dietary intake; the analytical methods applied in detecting phthalates in foods; and the implications for the food industry and policy makers for prevention and control of contamination and the future trends
Cyclostratigraphic and chronostratigraphic correlations in the Barremian-Aptian shallow-marine carbonates of the central-southern Apennines (Italy)
No full textWe present a high-resolution sedimentological analysis of Barremian-Aptian shallow-water carbonates from two cores (S. Maria 6 and 4) that were drilled in the central Apennines (central Italy) and one section (Monte Faito) that crops out in the southern Apennines (southern Italy). The aims of this work are (a) to propose a high-resolution correlation of sections that are located approximately 170 km apart in different tectonic units and paleogeographic domains using a microstratigraphic (cm-scale) approach and (b) to reveal global and regional mechanisms that control the stratigraphic architecture of these carbonate platform strata.
A composite S. Maria section was assembled by integrating the sedimentologic and biostratigraphic analyses of the two cores, which overlap each other across the Barremian-Aptian boundary. Both the S. Maria and the Monte Faito sections show repetitive facies patterns that are expressed as elementary cycles, which are hierarchically grouped into bundles and superbundles. The elementary cycles are meter-scale sedimentary units that are bounded by subaerial erosion surfaces, which directly overlie subtidal deposits. This implies that they formed under the influence of relative sea-level fluctuations. In both sections, the superbundles are organized into Transgressive/Regressive Facies Trends (T/RFTs), which are considered to be expressions of lower-frequency relative sea-level changes.
These deposits, like their Cretaceous analogues of other areas of the Apennines, show evidence of astronomically controlled eustatic oscillations, which are reflected in the hierarchical organization of their stacking patterns. They also exhibit a sequence-stratigraphic configuration that is best recognizable in the superbundles and T/RFTs. Based on integrated stratigraphic criteria, a high-resolution regional correlation between S. Maria and Monte Faito was developed and compared with the reference section of Monte Raggeto (M. Maggiore, southern Apennines, Italy), where biostratigraphic and cyclostratigraphic studies have been complemented by magneto- and isotope-stratigraphy.
We also propose a chronostratigraphic correlation between our T/RFTs and the Tethyan stratigraphic cycles of Hardenbol et al. (1998). Based on the cyclostratigraphic interpretation and orbital chronostratigraphy of the studied interval, we estimate a minimum duration of 5.2 my for the Barremian stage, which is similar to the 4.5 my duration from the Geological Time Scale of Gradstein et al., (2012)
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