18,080 research outputs found

    TransFearCity: insecurity, migrations and racism

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    Cities are enclaves where the excluded inhabitants from "geographies of deprivation" enhance together, whether they be national (internal flows) or international (external flows); motivated by economic, geopolitical or even environmental factors. Today, the plurality of discourse on the "other" has been polarized, remarking a resurgence of xenophobic and ultra-protectionist movements. This situation is observable in the repositioning of several political parties and their constituencies, which manifest a new sensitivity to immigration policies, sometimes contaminated by fear and ignorance of the "other." Simultaneously, there is a sometimes inadequate or inefficient management regarding the capacity of receiving new migrants, creating situations of exclusion and segregation that favor the appearance of ghettos or marginal neighborhoods in the urban periphery. Emphasizing the heterogeneity of migrants, their plurality and difference, we find on the one hand what we might call "migrant elites" associated with highly skilled workers, or as alternatives the workforce with no qualifications. These diverse groups also experience different realities that must be considered. Regardless of the migratory group, they may participate in urban life, both as part of their integration and through their direct-participatory action.In another hand, violence and insecurity are present in the daily lives of citizens, in different forms and intensities. These situations occur at different scales, from a micro-scale corresponding to interpersonal aggressions, such as school bullying; to a macro-scale, centered on abuses of power by large groups, corporations or institutions.info:eu-repo/semantics/publishedVersio

    Spectroscopic signatures of tetralayer graphene polytypes

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    Tetralayer graphene has recently become a new addition to the family of few-layer graphene with versatile electronic properties. This material can be realised in three distinctive stacking configurations, for which we determine spectroscopic signatures in angle-resolved photoemission spectroscopy (ARPES), dynamical optical conductivity, and Raman spectra of inter-band excitations. The reported library of spectral features of tetralayer graphenes can be used for the non-invasive identification of the stacking order realised in a particular film.Comment: Pages 11, figures

    ggtranscript: an R package for the visualization and interpretation of transcript isoforms using ggplot2

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    MOTIVATION: The advent of long-read sequencing technologies has increased demand for the visualisation and interpretation of transcripts. However, tools that perform such visualizations remain inflexible and lack the ability to easily identify differences between transcript structures. Here, we introduce ggtranscript, an R package that provides a fast and flexible method to visualize and compare transcripts. As a ggplot2 extension, ggtranscript inherits the functionality and familiarity of ggplot2 making it easy to use. AVAILABILITY: ggtranscript is an R package available at https://github.com/dzhang32/ggtranscript (DOI: https://doi.org/10.5281/zenodo.6374061) via an open-source MIT license. Further is available at https://dzhang32.github.io/ggtranscript/. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online

    CollectiveCity: the right to the city: 50 years later

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    The Third International Conference of Young Urban Researchers (TICYUrb) started the different sessions with the track CollectiveCity, the right to the city: 50 years later, commemorating the publication of "The Right to the City", one of the best well-known works of Henri Lefebvre. This track was divided in four sessions: Reflections on the Right to the City, Urban Resistance, Tourism and Urban Conflict and Housing Policies. Papers in this book are some of the works presented in the different sessions mentioned. These, and other works, responded to a challenge that we had launched to young urban researchers following Lefebvre’s lections today, especially on the emergent field of the Urban Studies. Lefebvre criticized an urban reality in which exchange value overlapped with use value, "right to urban life, transformed and renewed: "a right that concretizes collective needs, both for access to certain resources and for spatial appropriation or creative action on it. Several authors have made important contributions to the current reflection on the right to the city, among them: David Harvey, who understands the city as a work and, consequently, as an extension of the human being; and Neil Brenner, who has been reflecting on the process of planetary urbanization. In this sense, given the current importance of cities in a context of increasing urbanization, the different authors address the question on what is the current situation of the right to the city?info:eu-repo/semantics/publishedVersio

    Decay-assisted collinear resonance ionization spectroscopy: Application to neutron-deficient francium

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    This paper reports on the hyperfine-structure and radioactive-decay studies of the neutron-deficient francium isotopes 202206^{202-206}Fr performed with the Collinear Resonance Ionization Spectroscopy (CRIS) experiment at the ISOLDE facility, CERN. The high resolution innate to collinear laser spectroscopy is combined with the high efficiency of ion detection to provide a highly-sensitive technique to probe the hyperfine structure of exotic isotopes. The technique of decay-assisted laser spectroscopy is presented, whereby the isomeric ion beam is deflected to a decay spectroscopy station for alpha-decay tagging of the hyperfine components. Here, we present the first hyperfine-structure measurements of the neutron-deficient francium isotopes 202206^{202-206}Fr, in addition to the identification of the low-lying states of 202,204^{202,204}Fr performed at the CRIS experiment.Comment: Accepted for publication with Physical Review

    Laser spectroscopy of francium isotopes at the borders of the region of reflection asymmetry

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    The magnetic dipole moments and changes in mean-square charge radii of the neutron-rich 218m,219,229,231Fr^{218m,219,229,231}\text{Fr} isotopes were measured with the newly-installed Collinear Resonance Ionization Spectroscopy (CRIS) beam line at ISOLDE, CERN, probing the 7s 2S1/27s~^{2}S_{1/2} to 8p 2P3/28p~^{2}P_{3/2} atomic transition. The δr2A,221\delta\langle r^{2}\rangle^{A,221} values for 218m,219Fr^{218m,219}\text{Fr} and 229,231Fr^{229,231}\text{Fr} follow the observed increasing slope of the charge radii beyond N = 126N~=~126. The charge radii odd-even staggering in this neutron-rich region is discussed, showing that 220Fr^{220}\text{Fr} has a weakly inverted odd-even staggering while 228Fr^{228}\text{Fr} has normal staggering. This suggests that both isotopes reside at the borders of a region of inverted staggering, which has been associated with reflection-asymmetric shapes. The g(219Fr)=+0.69(1)g(^{219}\text{Fr}) = +0.69(1) value supports a π1h9/2\pi 1h_{9/2} shell model configuration for the ground state. The g(229,231Fr)g(^{229,231}\text{Fr}) values support the tentative Iπ(229,231Fr)=(1/2+)I^{\pi}(^{229,231}\text{Fr}) = (1/2^{+}) spin, and point to a πs1/21\pi s_{1/2}^{-1} intruder ground state configuration.Comment: Accepted for publication with Physical Review

    Sub-wavelength plasmonic-enhanced phase-change memory

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    The Ge2Sb2Te5 phase-change alloy (GST) is known for its dramatic complex refractive index (and electrical) contrast between its amorphous and crystalline phases. Switching between such phases is also non-volatile and can be achieved on the nanosecond timescale. The combination of GST with the widespread SiN integrated optical waveguide platform led to the proposal of the all-optical integrated phase-change memory, which exploits the interaction of the guided mode evanescent field with a thin layer of GST on the waveguide top surface. The relative simplicity of the architecture allows for its flexible application for data storage, logic gating, arithmetic and neuromorphic computing. Read operation relies on the transmitted signal optical attenuation, due to the GST extinction coefficient. Write/erase operations are performed via the same optical path, with a higher power ad-hoc pulsing scheme, which locally increases the temperature and triggers either the melt-quench process (write) or recrystallization (erase), encoding the information into the GST crystal fraction. Here we investigate the physical mechanisms involved in the write/erase and read processes via computational methods, with the view to explore novel architecture concepts that improve memory speed, energy efficiency and density. We show the achievements of the development of a 3D simulation framework, performing self-consistent calculations for wavepropagation, heat diffusion and phase-transition processes. We illustrate a viable memory optimization route, which adopts sub-wavelength plasmonic dimer nanoantenna structures to harvest the optical energy and maximize light-matter interaction. We calculate both a speed and energy efficiency improvement of around one order of magnitude, with respect to the conventional (non-plasmonic) device architecture

    The evolution of H{\sc ii} galaxies: Testing the bursting scenario through the use of self-consistent models

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    We have computed a series of realistic and self-consistent models of the emitted spectra of H{\sc ii} galaxies. Our models combine different codes of chemical evolution, evolutionary population synthesis and photoionization. The emitted spectrum of H{\sc ii} galaxies is reproduced by means of the photoionization code CLOUDY, using as ionizing spectrum the spectral energy distribution of the modelled H{\sc ii} galaxy, which in turn is calculated according to a Star Formation History (SFH) and a metallicity evolution given by a chemical evolution model that follows the abundances of 15 different elements. The contribution of emission lines to the broad-band colours is explicitly taken into account. The results of our code are compared with photometric and spectroscopic data of H{\sc ii} galaxies. Our technique reproduces observed diagnostic diagrams, abundances, equivalent width-colour and equivalent width-metallicity relations for local H{\sc ii} galaxies.Comment: 13 figures and 2 tables, accepted for publication in MNRAS Main Journa
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