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In the light of an increasing shift from international interventionism based on liberal peacebuilding to shorter-term stabilisation efforts, this article questions the persistence of the security–development nexus as a theoretical framework backing military and non-military action in conflict-affected areas. It argues that the nexus has been weakened by the prominence gained by regional and national actors on the African continent trying to enforce 'African solutions to African problems'. Drawing on interviews with key informants and mobilising relevant primary and secondary literature, the paper explores how ad hoc military coalitions created by African states to respond to crises on the continent are sanctioning the transition from long-term peacebuilding to short-term stabilisation objectives. Analysing the Nigerian government's counterinsurgency strategy against Boko Haram, we argue that the country has completely dropped the ambition to tackle the root causes of the insurgency, and has instead turned to short-term (and short-sighted) security stabilisation operations in line with the global trend of disengagement from active peacebuilding and development promotion. Thereby, we contend that the adoption of this kind of 'African solutions to African problems' equals militarised crisis-management in the continent's peripheries without advancing sustainable solutions to conflicts. [ABSTRACT FROM AUTHOR]

Integrating complementary information from many available technologies is a question of growing interest among the Cultural Heritage community, due to the complexity of the cultural assets under study and of their contexts. Recently, this need has pushed the development of appropriate data fusion procedures for this sector, among which the authors wish to propose their approach for treating multi-source data from image-based methodologies, experimented with in a representative case study. The Chigi Palace of Ariccia hosted our investigation campaign on a precious monochrome painting by Giuseppe Cades (1788), the Graecia Vetus. The study encompasses a photogrammetric survey and two acoustic diagnostic methods, the innovative Frequency Resolved Acoustic Imaging technique and the more traditional Acoustic Tomography. The photogrammetric survey allows reconstruction of the surface morphology of the painting, generating a 3D Digital Elevation Model, while the acoustic methods detect the structural damage beneath the surface due to detachments and flaws, generating 2D images. The output of this heterogeneous datasets fusion is a multi-layer map, each layer representing a type of dataset that clearly shows how some deformations of the surface morphology appear correlated with the presence of sub-surface anomalies, wide air cavities and more superficial detachments revealed by the acoustic diagnostic methods. Beside the exam of the conservation state of the Graecia Vetus, the proposed procedure effectively guarantees access to the integrated information, offering the possibility to understand the correlation between the causes and the effects of the decay process, as well as the retrieval of the single analysis in order to deepen one specific aspect. [ABSTRACT FROM AUTHOR]

A theoretical and experimental framework for the characterization of the terahertz (THz) conductivity of graphene on metal-backed substrates is presented. Analytical equations are derived for the general problem of oblique incidence of the THz beam in a time-domain spectroscopic (TDS) setup working in reflection. The recorded time-domain signals are post-processed in order to retrieve the substrate thickness, its dielectric frequency dispersion, and the complex graphene conductivity frequency dispersion, which is described by a generalized Drudeâ€"Smith model. The method is tested on two samples of chemical vapor deposited graphene, transferred on polyethylene terephthalate and cyclo-olefin polymeric substrates of sub-millimetric thickness, and characterized by Raman spectroscopy. By working only with the amplitude spectra, the proposed method circumvents issues stemming from phase uncertainties that typically affect TDS measurements in reflection mode. More important, it allows for a rapid, nondestructive characterization of graphene sheets that can be directly integrated in the production flow of graphene-based passive or active components employing metal-backed resonant cavities, such as THz absorbers, metasurface lenses, or leaky-wave antennas. [ABSTRACT FROM AUTHOR]

Uganda is the third country in the world for absolute numbers of refugees hosted. Why is this the case? Is it just a geographical accident, or does it gain benefits from its open policy? This article contributes to the literature addressing these questions by shedding light on how a refugee emergency can be used for state-building purposes. Thanks to its history as a donor darling, Uganda was able to position itself as a model for refugee-hosting, receiving significant amounts of international aid to sustain the country's extraversion strategies. Even though the state-building project nurtured by these resources is not a liberal one, being marred by corruption and scandal, it cannot be dismissed as individual rent-seeking. The paper shows that this project aims to recentralization and the strengthening of the incumbent regime through the strengthening of the central state structure in the refugee-hosting peripheries to the detriment of local governments. [ABSTRACT FROM AUTHOR]

Recent literature on refugees' agency has shed light on refugees' capacity to claim political subjectivity and to creatively engage with their condition of vulnerability. Drawing on this literature, this article shows how refugees manage to reinvent spaces of participation created from the top down in refugee settlements, turning them from invited spaces to something more akin to invented spaces of participation. It does so through the analysis of Refugee Welfare Councils, local governance institutions created by the Ugandan government and UNHCR in refugee settlements, and drawing on field research conducted in April–June 2018 in Adjumani District, Uganda. The article argues that Refugee Welfare Councils (RWCs) are turned into invented spaces of participation, through which refugees undertake actions that produce a form of local citizenship based on claiming rights to food and services, the reorganization of society through the emergence of new leadership structures, and the production of new forms of identity and belonging. These all contribute to the emergence of a new imagined community which is based on geographical proximity and on the shared experience of exile, distancing itself from prevalent traditional forms of identification and belonging in South Sudanese society. [ABSTRACT FROM AUTHOR]

The concept of human security became popular in the 1990s as a new framework for conceptualising security, shifting its referent from states to human beings and expanding its scope. While acknowledging the widespread criticism and rich debate that developed around the concept of human security after its appearance, this paper analyses the context in which human security emerged as a concept and reviews its different usages with a particular focus on its application to Africa and refugee-hosting areas. It maintains that the contribution of this concept goes beyond the simple statement that security is a matter of people's lives. Thanks to its focus on subjective understandings of security, human security can be used as an analytical framework to produce context-specific knowledge about security based on people's perceptions of what makes them secure/insecure and on local practices of human security – what people do to feel more secure. The application of a human security framework to refugee-hosting areas in Africa would contribute towards enhancing refugees' agency in a context often dominated by a victimising narrative, as well as providing a comprehensive understanding of security priorities, providing important information for more context-specific policymaking. [ABSTRACT FROM AUTHOR]

Southern Sudan's past crises have mobilised consistent flows of humanitarian assistance. Recalling the humanitarian catastrophes and international interventions of the 1990s–2000s, the war that exploded in South Sudan in 2013 has been no exception. This paper shows that the SPLM/A political elite promptly incorporated these flows of external resources into its extraverted strategies of state-building. Similar to the current situation, it did so by appropriating not only material assets but also discourses, playing the ‘fragile state’ card and raising fears of governance failure and state collapse. This paper analyses two specific aspects of international support to Southern Sudan in the 1990s–2000s: the political legitimisation of the movement through the negotiation of relief delivery, and direct support to rebel local government structures. These two aspects contributed to the creation of a state that substantially overlapped with the SPLM/A structure, thanks to the movement's capacity to capitalise on external resources, a subject worth analysing in future research. [ABSTRACT FROM AUTHOR]

A new application of a contactless and low-cost acoustic imaging technique, for the diagnostics of the structural damage in panel paintings is presented. The artworks, exposed to a wide frequency band acoustic excitation, are analysed in terms of acoustic energy absorption coefficient in the audio frequency interval. The method reveals buried defects, such as detachments of the painted layer and flaws in the wood substrate, providing frequency resolved acoustic images. Three case studies are here discussed; the wood substrate configuration and the conservation state of the painted layer greatly differentiate the examined paintings. A collection of acoustic images is presented, highlighting a plurality of features characterized by different geometry and frequency response. The study gives a representative visualization of the response of panel paintings to the acoustic excitation, suggesting a reliable usefulness of this technique in their safeguard. This knowledge base will orient the future validation on properly designed laboratory models. [ABSTRACT FROM AUTHOR]

The morphological, structural, and electrical properties of as-grown and annealed Ge2Sb2Te5 (GST) layers, deposited by RF-sputtering on flexible polyimide, were studied by means of optical microscopy, atomic force microscopy, X-ray diffraction, Raman spectroscopy, and electrical characterization. The X-ray diffraction annealing experiments showed the structural transformation of GST layers from the as-grown amorphous state into their crystalline cubic and trigonal phases. The onset of crystallization of the GST films was inferred at about 140 °C. The vibrational properties of the crystalline GST layers were investigated via Raman spectroscopy with mode assignment in agreement with previous works on GST films grown on rigid substrates. The electrical characterization revealed a good homogeneity of the amorphous and crystalline trigonal GST with an electrical resistance contrast of 8 × 106. [ABSTRACT FROM AUTHOR]

Black phosphorus nanosheets (2D BP) are emerging as very promising, highly selective chemotherapeutic agents due to their fast degradation in the intracellular matrix of cancer cells. Here, optical diffraction tomography (ODT) and Raman spectroscopy were exploited as a powerful label-free approach to achieve integrated insights into the processes accompanying the administration of exfoliated 2D BP flakes in human prostatic adenocarcinoma and normal human prostate epithelial cells. Our ODT experiments provided unambiguous visualization of the 2D BP internalization in cancer cells and the morphological modifications of those cells in the apoptotic phase. The cellular internalization and damaging occurred, respectively, 18 h and 36–48 h after the 2D BP administration. Changes in the chemical properties of the internalized 2D BP flakes were monitored by Raman spectroscopy. Interestingly, a fast oxidation process of the 2D BP flakes was activated in the intracellular matrix of the cancer cells after 24 h of incubation. This was in sharp contrast to the low 2D BP uptake and minimal chemical changes observed in the normal cells. Along with the understanding of the 2D BP fate in the cancer cells, the proposed label-free morpho-molecular approach offers a powerful, rapid tool to study the pharmacokinetic properties of engineered nanomaterials in preclinical research. [ABSTRACT FROM AUTHOR]

In this study, we deposit a Ge-rich Ge–Sb–Te alloy by physical vapor deposition (PVD) in the amorphous phase on silicon substrates. We study in-situ, by X-ray and ultraviolet photoemission spectroscopies (XPS and UPS), the electronic properties and carefully ascertain the alloy composition to be GST 29 20 28. Subsequently, Raman spectroscopy is employed to corroborate the results from the photoemission study. X-ray diffraction is used upon annealing to study the crystallization of such an alloy and identify the effects of phase separation and segregation of crystalline Ge with the formation of grains along the [111] direction, as expected for such Ge-rich Ge–Sb–Te alloys. In addition, we report on the electrical characterization of single memory cells containing the Ge-rich Ge–Sb–Te alloy, including I-V characteristic curves, programming curves, and SET and RESET operation performance, as well as upon annealing temperature. A fair alignment of the electrical parameters with the current state-of-the-art of conventional (GeTe)n-(Sb2Te3)m alloys, deposited by PVD, is found, but with enhanced thermal stability, which allows for data retention up to 230 °C. [ABSTRACT FROM AUTHOR]

Ge-rich Ge–Sb–Te compounds are attractive materials for future phase change memories due to their greater crystallization temperature as it provides a wide range of applications. Herein, we report the self-assembled Ge-rich Ge–Sb–Te/Sb2Te3 core-shell nanowires grown by metal-organic chemical vapor deposition. The core Ge-rich Ge–Sb–Te nanowires were self-assembled through the vapor–liquid–solid mechanism, catalyzed by Au nanoparticles on Si (100) and SiO2/Si substrates; conformal overgrowth of the Sb2Te3 shell was subsequently performed at room temperature to realize the core-shell heterostructures. Both Ge-rich Ge–Sb–Te core and Ge-rich Ge–Sb–Te/Sb2Te3 core-shell nanowires were extensively characterized by means of scanning electron microscopy, high resolution transmission electron microscopy, X-ray diffraction, Raman microspectroscopy, and electron energy loss spectroscopy to analyze the surface morphology, crystalline structure, vibrational properties, and elemental composition. [ABSTRACT FROM AUTHOR]

Abstract: Diurnal variations in total ozone column were observed to exceed 40DU during the QAARC campaign of late spring 2009 held at the Ny-Ålesund Arctic station in Svalbard. They were correlated to corresponding oscillations of surface UV-B irradiance, assuming that the strong dependence between these two variables ensures the reliability of registered total ozone oscillations. To make the comparison, an approach is proposed that allows the retrieval of diurnal variability in UV-B irradiance due to total ozone column changes, for application to the data collected during the campaign. The UV irradiance features observed with the reference spectroradiometer over a 7-day period were analyzed together with the corresponding ozone column data-sets, simultaneously obtained using two different devices. Power curves were found to provide the best-fit solutions for the retrieved UV-B variations, examined as a function of total ozone variations. Such approximations are characterized by regression coefficients of about −0.94 and by the exponent named in earlier studies as the radiation amplification factor (RAF), which was found to vary between 0.79 and 2.49. These RAF evaluations are in good agreement with previous estimates derived from both field measurements and model evaluations, which confirm the complete dependability of the short-term variations in the ozone column measured at Ny-Ålesund. [Copyright &y& Elsevier]

San Nicola in Carcere, one of the minor basilicas in the historical center of Rome, was the location of a wide investigation campaign of the water-related deterioration causes, present in the lower sector of the apse and adjacent pillars, affected by water infiltrations, mould and salt efflorescence. The results obtained identify the presence of water content and related effects mainly on the sides of the apsidal wall. This work focuses on the use of five Non-Destructive Techniques (NDT) and intends to show the gains obtained by integrating widely interdisciplinary methods, namely the Infrared Thermography (IRT), the Unilateral Nuclear Magnetic Resonance (Unilateral NMR), the Acoustic Tomography (AT), the Acoustic Imaging (AI) and the Laser-Induced Fluorescence (LIF). All the techniques contribute to the rapid, non-invasive and early identification of the moisture distribution, while some of them (LIF and AI) also address the determination of some moisture effects. The integrated use of different techniques helps to take the multidisciplinary point of view necessary to formulate an effective restoration intervention based on a sound scientific rationale; nonetheless, it allows to experiment a holistic approach, verifying the potential of a wide range of NDTs available within the context of a restoration yard. [ABSTRACT FROM AUTHOR]