244 research outputs found

    New strategies to study organizations working with people experiencing homelessness: the service providers’ study

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    Structure and dynamics of the fullerene polymer Li4 C60 studied with neutron scattering

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    The two-dimensional polymer structure and lattice dynamics of the superionic conductor Li4 C60 are investigated by neutron diffraction and spectroscopy. The peculiar bonding architecture of this compound is definitely confirmed through the precise localisation of the carbon atoms involved in the intermolecular bonds. The spectral features of this phase are revealed through ab-initio lattice dynamics calculations and inelastic neutron scattering experiments. The neutron observables are found to be in very good agreement with the simulations which predict a partial charge transfer from the Li atoms to the C60 cage. The absence of a well defined band associated to one category of the Li atoms in the experimental spectrum suggests that this species is not ordered even at the lowest temperatures. The calculations predict an unstable Li sublattice at a temperature of 200 K, that we relate to the large ionic diffusivity of this system. This specificity is discussed in terms of coupling between the low frequency optic modes of the Li ions to the soft structure of the polymer.Comment: 29 pages, 13 Figure

    Resource-driven Substructural Defeasible Logic

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    Linear Logic and Defeasible Logic have been adopted to formalise different features relevant to agents: consumption of resources, and reasoning with exceptions. We propose a framework to combine sub-structural features, corresponding to the consumption of resources, with defeasibility aspects, and we discuss the design choices for the framework

    Deciphering the Interplay between Binders and Electrolytes on the Performance of Li4Ti5O12 Electrodes for Li-Ion Batteries

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    Lithium titanium oxide (Li4Ti5O12, LTO) is an attractive negative electrode for the development of safe-next-generation-lithium-ion batteries (LIBs). LTO can find specific applications complementary to existing alternatives for LIBs thanks to its good rate capability at high C-rates, fast lithium intercalation, and high cycling stability. Furthermore, LIBs featuring LTO electrodes are inherently safer owing to the LTO's operating potential of 1.55 V vs. Li+/Li where the commonly used organic-based electrolytes are thermodynamically stable. Herein, we report the combined use of water-soluble sodium alginate (SA) binder and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)-tetraglyme (1m-T) electrolyte and we demonstrate the improvement of the electrochemical performance of LTO-based electrodes with respect to those operating in conventional electrolyte 1M LiPF6-ethylene carbonate: dimethyl carbonate (LP30). We also tackle the analysis of the impact of combining the binder/electrolyte on the long-term cycling performance of LTO electrodes featuring SA or conventional polyvinylidene fluoride (PVdF) as binders. Therefore, to assess the impact of the combination of binder/electrolyte on performance, we performed post-mortem characterization by ex situ synchrotron diffraction experiments of LTO electrodes after cycling in LP30 and 1m-T electrolytes

    Differentially Private Model Selection with Penalized and Constrained Likelihood

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    In statistical disclosure control, the goal of data analysis is twofold: The released information must provide accurate and useful statistics about the underlying population of interest, while minimizing the potential for an individual record to be identified. In recent years, the notion of differential privacy has received much attention in theoretical computer science, machine learning, and statistics. It provides a rigorous and strong notion of protection for individuals' sensitive information. A fundamental question is how to incorporate differential privacy into traditional statistical inference procedures. In this paper we study model selection in multivariate linear regression under the constraint of differential privacy. We show that model selection procedures based on penalized least squares or likelihood can be made differentially private by a combination of regularization and randomization, and propose two algorithms to do so. We show that our private procedures are consistent under essentially the same conditions as the corresponding non-private procedures. We also find that under differential privacy, the procedure becomes more sensitive to the tuning parameters. We illustrate and evaluate our method using simulation studies and two real data examples

    Higher-Order Probabilistic Adversarial Computations: {C}ategorical Semantics and Program Logics

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    Passive adaptation or active engagement? the challenges of Housing First internationally and in the Italian case

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    In recent years a peculiar homelessness’ policy that goes under the name of ‘Housing First’ has become increasingly popular all over the world. Epitomising a quintessential case of policy-mobility, Housing First can today be considered an heterogeneous assemblage of experiences and approaches that sometimes have little in common with each other. Introducing and commenting upon this heterogeneity, the paper critically analyses why and how Housing First has become a planetary success and what are the issues at stake with its widespread implementation. If recent scholarship published in this journal has granted us a fine understanding of Housing First’s functioning in the US, this paper offers something currently absent from the debate: a nuanced and critical understanding of the ambiguities related to the international success of this policy, with specific references to the challenges associated to its translation in the Italian case

    Large scale synthesis of copper nickel alloy nanoparticles with reduced compressibility using arc thermal plasma process

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    Among the various methods employed in the synthesis of nanostructures, those involving high operating temperature and sharp thermal gradients often lead to the establishment of new exotic properties. Herein, we report on the formation of Cu-Ni metallic alloy nanoparticles with greatly enhanced stiffness achieved through direct-current transferred arc-thermal plasma assisted vapour-phase condensation. High pressure synchrotron X-ray powder diffraction (XRPD) at ambient temperature as well as XRPD in the temperature range 180 to 920 K, show that the thermal arc-plasma route resulted in alloy nanoparticles with much enhanced bulk modulus compared to their bulk counterparts. Such a behaviour may find an explanation in the sudden quenching assisted by the retention of a large amount of local strain due to alloying, combined with the perfect miscibility of the elemental components during the thermal plasma synthesis process

    Linguistic markers of processing the first months of the pandemic COVID-19: a psycholinguistic analysis of Italian university students' diaries

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    A longitudinal psycholinguistic study was conducted with 107 students from different Italian universities that produced daily photo-diary entries for two weeks, one at the beginning and the other at the end of the first Italian lockdown period, imposed in view of the rapid dissemination of COVID -19. The task was to take a daily photo accompanied by a short description (text). The texts accompanying the photos were analysed using Linguistic Inquiry and Word Count (LIWC) software to analyze linguistic markers representing psychological processes related to the experience of the pandemic and the lockdown, identifying potential changes in psycholinguistic variables useful for understanding the psychological impact of such harsh and extended restricted living conditions on Italian students. LIWC categories related to negation, anger, cognitive mechanisms, tentative discourse, past, and future increased statistically significantly between the two time points, while word count, prepositions, communication, leisure, and home decreased statistically significantly. While male participants used more articles at both time points, females used more words related to anxiety, social processes, past, and present at T1 and more related to insight at T2. Participants who lived with their partner showed higher scores on negative emotions, affect, positive feelings, anger, optimism, and certainty. Participants from southern Italy tended to describe their experiences from a collective and social perspective rather than an individual perspective. By identifying, discussing, and comparing these phenomena with the broader literature, a spotlight is shed for the first time on the psycholinguistic analysis of students at the national level who faced the first COVID -19 lockdown in Italy
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