Building a Lifeline: A Proposed Global Platform and Responsibility Sharing Model for the Global Compact on Refugees

In 2016, the leaders of 193 governments committed to more equitable and predictable sharing of responsibility for refugees as part of the New York Declaration, to be realized in the Global Compact on Refugees. To encourage debate, this paper presents the first global model to measure the capacity of governments to physically protect and financially support refugees and host communities. The model is based on a new database of indicators covering 193 countries, which assigns a fair share to each country and measures current government contributions to the protection of refugees. The model also proposes a new government-led global platform in support of refugee protection and human development. In January 2019, an overwhelming majority of U.N. Member States adopted a resolution affirming the Global Compact on Refugees. This pact of international solidarity and cooperation is more important today than ever—as powerful countries double-down on xenophobia, promote toxic politics, and drastically narrow their contributions to refugee protection. While the Refugee Compact has the potential to provide better protection and care for refugee and host communities, it is not legally binding. Its promises may only be realized through the adoption of a concrete model for equitable and predictable responsibility sharing based on each nation’s capacity to receive and/or care for refugees. The responsibility sharing model presented here is put forward to challenge policymakers and help shape discussions toward an agreed upon approach to determining each nation’s capacity based on a data-driven approach as contemplated in the Refugee Compact

Modelling of amorphous polymer surfaces in computer simulation

We study surface effects in amorphous polymer systems by means of computer simulation. In the framework of molecular dynamics, we present two different methods to prepare such surfaces. {\em Free} surfaces are stabilized solely by van--der--Waals interactions whereas {\em confined} surfaces emerge in the presence of repelling plates. The two models are compared in various computer simulations. For free surfaces, we analyze the migration of end--monomers to the surface. The buildup of density and pressure profiles from zero to their bulk values depends on the surface preparation method. In the case of confined surfaces, we find density and pressure oszillations next to the repelling plates. We investigate the influence of surfaces on the coordination number, on the orientation of single bonds, and on polymer end--to--end vectors. Furthermore, different statistical methods to determine location and width of the surface region for systems of various chain lengths are discussed and applied. We introduce a ``height function'' and show that this method allows to determine average surface profiles only by scanning the outermost layer of monomers.Comment: 23 pages, 12 figure

Opinion leader online e sfere pubbliche nella Cina contemporanea. L’impatto di internet sulla società della Repubblica popolare cinese

La presente ricerca analizza l’impatto degli opinion leader del web (wangluo yijian lingxiu) sulla formazione dell’opinione pubblica in Cina e descrive il modo in cui il loro operato influenza la società contemporanea. Con l’importanza accordata dal governo al settore delle tecnologie dell’informazione e della comunicazione (ICT), e in particolare con l’avvento dei nuovi media e di internet nel 1994, sia le forme che i contenuti della comunicazione di temi politici e sociali nella Repubblica popolare cinese si sono trasformati radicalmente, agevolando in talune circostanze una maggiore partecipazione della popolazione al discorso pubblico nazionale. È in questo mutato contesto tecnologico, e più precisamente nello spazio astratto che intercorre tra i media tradizionali e le masse, che si colloca la figura dell’opinion leader online. Tra gli attori più interessanti sulle piattaforme digitali cinesi, giornalisti, autori, intellettuali e imprenditori che fanno parte di questa categoria sono capaci di influenzare l’opinione pubblica in settori differenti, stimolando spesso il dibattito su temi sensibili di natura politica e sociale (mingan huati). Sfruttando la relativa libertà di cui possono godere sulle piattaforme digitali, essi filtrano e interpretano i messaggi ufficiali dei media e li diffondono verso i milioni di utenti che ne seguono l’attività, condizionando il livello di priorità dei temi sull’agenda politica nazionale. Rispetto ai media tradizionali, hanno inoltre una maggiore efficacia poiché al pubblico la loro azione appare trasparente, priva di secondi fini e di conseguenza maggiormente credibile

Interfering Effects of Growing Chain Epimerization on Metallocene-Catalyzed Isotactic Propene Polymerization

The stereoregularity of polypropylene produced with C2-symmetric group 4 ansa-metallocene catalysts results from the interplay of two competing reactions, namely isotactic monomer polyinsertion and a side process of epimerization of the polymer chain at its active end; therefore, for this class of homogeneous catalysts, at variance with the “classical” heterogeneous Ziegler−Natta ones, enantioselectivity and stereoselectivity are not (necessarily) coincident. In this paper, possible methods for the separate determination of these two parameters are introduced and applied to propene polymerization in the presence of the prototypical catalyst rac-ethylene−bis(4,5,6,7-tetrahydro-1-indenyl)ZrCl2. The results prove that the relatively poor stereoselectivity of this catalyst above room temperature is consequent primarily to chain epimerization; monomer insertion indeed is highly enantioselective up to at least 80 °C. Preliminary evidence for the existence of more than one epimerization mechanism is also presented; this complicates the measurements of enantioselectivity based on 13C NMR characterizations of d-labeled poly(propene)

La documentazione archeologica digitale presso il cantiere di Leopoli-Cencelle (Tarquinia, VT)

The excavation of the medieval city of Leopoli-Cencelle (Tarquinia, VT) has reached its 24th campaign. The graphic documentation produced over this period faithfully reflects how Information Technologies and instruments for data acquisition have developed in the course of about 20 years. In the case of Leopoli-Cencelle, the main challenge was to produce a modern system of managing and using data and to subsume all the paper elements into one functional and searchable digital format

UAVIMALS: THE "OPEN" REMOTE SENSING SYSTEM FOR SURFACE ARCHAEOLOGICAL INVESTIGATIONS

Today, there is an increasing use of airborne sensors in archaeology, especially to investigate the surface of more or less vast territories quickly and accurately. In particular, airborne laser scanning technologies from small remotely piloted aircraft are rapidly developing towards increasingly high-performance solutions for the investigation of archaeological evidence hidden by vegetation or more or less substantial soil deposits. The proposed contribution intends to insert itself within this field of archaeological research by presenting "UAVIMALS" (Unmanned Aerial Vehicle Integrated with Micro Airborne Laser Scanner), an aerial remote sensing system of "soil marks", designed for surface archaeological investigations and the result of an Early Career Grant from the National Geographic Society. The system, consisting of a customised drone based on an open architecture and software for vehicle control and data processing, integrates a solid-state laser sensor, commonly engineered for obstacle avoidance, but here exploited to process accurate DTM (Digital Terrain Model) of small land surfaces with a significant reduction in cost and acquisition time. The system, whose engineering was contributed by the BioRobotics Institute of the S. Anna University of Pisa, was tested within the archaeological context of Leopoli - Cencelle (Tarquinia, Italy). A mediaeval city that has been researched for about 25 years by the Chair of Christian and Medieval Archaeology at the 'Sapienza' University of Rome. Experimentation missions carried out on the site, which is still only partially investigated, have been successful in bringing to light some urban areas that had not yet been investigated

On modifying properties of polymeric melts by nanoscopic particles

We study geometric and energetic factors that partake in modifying properties of polymeric melts via inserting well-dispersed nanoscopic particles (NP). Model systems are polybutadiene melts including 10-150 atom atomic clusters (0.1-1.5% v/v). We tune interactions between chains and particle by van der Waals terms. Using molecular dynamics we study equilibrium fluctuations and dynamical properties at the interface. Effect of bead size and interaction strength both on volume and volumetric fluctuations is manifested in mechanical properties, quantified here by bulk modulus, K. Tuning NP size and non-bonded interactions results in ~15% enhancement in K by addition of a maximum of 1.5% v/v NP.Comment: 25 pages, 7 figure

Modeling of Intermediate Structures and Chain Conformation in Silica-Latex Nanocomposites Observed by SANS During Annealing

The evolution of the polymer structure during nanocomposite formation and annealing of silica-latex nanocomposites is studied using contrast-variation small angle neutron scattering. The experimental system is made of silica nanoparticles (Rsi \approx 8 nm) and a mixture of purpose-synthesized hydrogenated and deuterated nanolatex (Rlatex \approx 12.5 nm). The progressive disappearance of the latex beads by chain interdiffusion and release in the nanocomposites is analyzed quantitatively with a model for the scattered intensity of hairy latex beads and an RPA description of the free chains. In silica-free matrices and nanocomposites of low silica content (7%v), the annealing procedure over weeks at up to Tg + 85 K results in a molecular dispersion of chains, the radius of gyration of which is reported. At higher silica content (20%v), chain interdiffusion seems to be slowed down on time-scales of weeks, reaching a molecular dispersion only at the strongest annealing. Chain radii of gyration are found to be unaffected by the presence of the silica filler

Combined Molecular Algorithms for the Generation, Equilibration and Topological Analysis of Entangled Polymers: Methodology and Performance

We review the methodology, algorithmic implementation and performance characteristics of a hierarchical modeling scheme for the generation, equilibration and topological analysis of polymer systems at various levels of molecular description: from atomistic polyethylene samples to random packings of freely-jointed chains of tangent hard spheres of uniform size. Our analysis focuses on hitherto less discussed algorithmic details of the implementation of both, the Monte Carlo (MC) procedure for the system generation and equilibration, and a postprocessing step, where we identify the underlying topological structure of the simulated systems in the form of primitive paths. In order to demonstrate our arguments, we study how molecular length and packing density (volume fraction) affect the performance of the MC scheme built around chain-connectivity altering moves. In parallel, we quantify the effect of finite system size, of polydispersity, and of the definition of the number of entanglements (and related entanglement molecular weight) on the results about the primitive path network. Along these lines we approve main concepts which had been previously proposed in the literature