282 research outputs found

    Silicon Drift Detectors for basic and applied research

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    Global value chains and deep integration

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    The post-1990 period has seen a proliferation of preferential trade agreements (PTAs). Some 700 PTAs are currently in force, compared to a little more than 100 PTAs before 1990. Both developed and developing countries have been and are deeply involved in preferential trade liberalisation. While tariff reductions on a preferential basis are a central feature of all trade agreements, the inclusion of provisions that do not pertain directly to merchandise trade policies – e.g. provisions protecting foreign investment (FDI) and liberalising access to markets for services – has become increasingly common in PTAs. As a result, many PTAs regulate trade-related issues more extensively and more stringently than the WTO. Simply put, preferential liberalisation has become the main instrument of trade policy cooperation

    Adhesion of Immature and Mature T Cells Induces in Human Thymic Epithelial Cells (TEC) Activation of IL-6 Gene Trascription Factors (NF-κB And NF-IL6) and IL-6 Gene Expression : Role of αtβ1 and α6β4 Integrins

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    T cell precursors homed to thymus develop in close contact with stromal cells. Among them, thymic epithelial cells (TEC) are known to exert dominant roles in their survival and functional shaping. Key molecules mediating TEC/thymocytes interactions include cytokines and growth factors secreted by the two cell types and adhesion receptors mediating cell contact. Signaling events triggered in thymocytes by adhesion to epithelial cells have been extensively investigated, whereas little is known on the opposite phenomenon. We have previously investigated this issue in a co-culture system composed of TEC cultures derived from human normal thymus and heterologous thymocytes. We demonstrated that thymocytes adhere to TEC involving β1 and β4 integrins and induce the clustering of (α3β1 and α6β4 heterodimers at the TEC surface. In addition thymocyte adhesion was followed by activation of NF-κB and NF-IL6 gene transciption factors and enhanced IL-6 production. The two latter phenomena were reproduced by the cross-linking of the α3, α6, β1 and β4 integrins, thus implying that the α3β1 and α6β4 heterodimers can signal during thymocyte adhesion. We have extended our previous work investigating in the same experimental setting the inducing activity of non stimulated or activated policlonal or clonal mature T cells as representative of the more mature thymocyte subset. We found that adhesion of unstimulated T cell i) involved β1, but not β4 integrin functions at the surface ii) induced the clustering of α3β1 , but not α2β1 heterodimers at the TEC surface and iii) up-regulated the nuclear binding activity of NF-κB transcription factor and the IL-6 secretion. We propose that α3β1 and α6β4 heterodimers are induced to cluster at the TEC surface recognizing yet unknown cellular ligands differentially expressed during T cell development

    Global value chains and the design of trade agreements

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    We explore the role of global value chains (GVCs) in the design of preferential trade agreements (PTAs). We propose a theory that focuses on firms involved in backward and forward GVC activities to identify the main actors pushing for deep trade integration. To address the critical issue of endogeneity of trade flows for trade policy, our identification strategy exploits a transportation shock: The sharp increase in the maximum size of container ships, which more than quadrupled between 1995 and 2017. The key variation in our instrument hinges on the fact that only deepwater ports can accommodate these new larger ships. Our strategy is flexible enough to generate excludable instruments for different value-added components of exports, which allows us to disaggregate the causal effect of GVC participation into backward and forward GVC activities. We find that trade through GVCs increases the probability of forming deep PTAs that include provisions regulating both trade-related and non-trade-related policies. We find also evidence that GVC activities affect the flexibility of PTAs. Our results indicate that trade intermediation by producers is the main driver of the design of trade agreements

    Biochemical and neuropathological findings in a Creutzfeldt-Jakob Disease patient with the rare Val180Ile-129Val haplotype in the prion protein gene

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    Genetic Creutzfeldt-Jakob disease (gCJD) associated with the V180I mutation in the prion protein (PrP) gene (PRNP) in phase with residue 129M is the most frequent cause of gCJD in East Asia, whereas it is quite uncommon in Caucasians. We report on a gCJD patient with the rare V180I-129V haplotype, showing an unusually long duration of the disease and a characteristic pathological PrP (PrPSc) glycotype. Family members carrying the mutation were fully asymptomatic, as commonly observed with this mutation. Neuropathological examination showed a lesion pattern corresponding to that commonly reported in Japanese V180I cases with vacuolization and gliosis of the cerebral cortexes, olfactory areas, hippocampus and amygdala. PrP was deposited with a punctate, synaptic-like pattern in the cerebral cortex, amygdala and olfactory tract. Western blot analyses of proteinase-K-resistant PrP showed the characteristic two-banding pattern of V180I gCJD, composed of mono- and un-glycosylated isoforms. In line with reports on other V180I cases in the literature, Real-Time Quaking Induced Conversion (RT-QuIC) analyses did not demonstrate the presence of seeding activity in the cerebrospinal fluid and olfactory mucosa, suggesting that this haplotype also may result in a reduced seeding efficiency of the pathological PrP. Further studies are required to understand the origin, penetrance, disease phenotype and transmissibility of 180I-129V haplotype in Caucasians

    VIP-2 —High-Sensitivity Tests on the Pauli Exclusion Principle for Electrons

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    The VIP collaboration is performing high sensitivity tests of the Pauli Exclusion Principle for electrons in the extremely low cosmic background environment of the underground Gran Sasso National Laboratory INFN (Italy). In particular, the VIP-2 Open Systems experiment was conceived to put strong constraints on those Pauli Exclusion Principle violation models which respect the so-called Messiah–Greenberg superselection rule. The experimental technique consists of introducing a direct current in a copper conductor, and searching for the X-rays emission coming from a forbidden atomic transition from the L shell to the K shell of copper when the K shell is already occupied by two electrons. The analysis of the first three months of collected data (in 2018) is presented. The obtained result represents the best bound on the Pauli Exclusion Principle violation probability which fulfills the Messiah–Greenberg rule

    High Precision Test of the Pauli Exclusion Principle for Electrons

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    The VIP-2 experiment aims to perform high precision tests of the Pauli Exclusion Principle for electrons. The method consists in circulating a continuous current in a copper strip, searching for the X radiation emission due to a prohibited transition (from the 2p level to the 1s level of copper when this is already occupied by two electrons). VIP already set the best limit on the PEP violation probability for electrons 12β2<4.7×1029\frac{1}{2} \beta^2 < 4.7 \times 10^{-29}, the goal of the upgraded VIP-2 (VIolation of the Pauli Exclusion Principle-2) experiment is to improve this result of two orders of magnitude at least. The experimental apparatus and the results of the analysis of a first set of collected data will be presented

    Search for a remnant violation of the Pauli exclusion principle in a Roman lead target

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    In this paper we report on the results of two analyses of the data taken with a dedicated VIP-Lead experiment at the Gran Sasso National Laboratory of the INFN. We use measurements taken in an environment that is especially well screened from cosmic rays, with a metal target made of “Roman lead” which is characterised by a low level of intrinsic radioactivity. The analyses lead to an improvement, on the upper bounds of the Pauli Exclusion Principle violation for electrons, which is more than one (four) orders of magnitude, when the electron-atom interactions are described in terms of scatterings (or close encounters) respectively
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