Of fixes and glitches:Mixing metaphors for platform urbanism

The growing influence of digital platforms on cities has captured the attention of urban scholars, marking a ‘platform pivot’ in digital geography and urban research. This article reviews emerging literature on platform urbanism, using the metaphors of the fix and the glitch as starting points from which to discuss two contrasting perspectives on the phenomenon. Rooted in Marxist political economy, fix-thinking highlights how platforms generate new opportunities for value-extraction through processes of disembedding, datafication and deregulation. Influenced by feminist, queer and Black media studies, glitch-thinking performatively underscores the breakdowns and openings in the working of platforms. Where fix-thinking highlights the role of platforms in furthering urban capitalism, glitch-thinking encourages us to envision how things could be otherwise. The review leads to two original insights that may further knowledge on this phenomenon. First, it points to a gap in research investigating instances when breakdown and disruptions turn into organised action and sustained social change. Second, it underscores the citational politics that limit engagements between the two strands, and the potential usefulness of drawing on earlier scholarship that softens or challenge the ‘fix-glitch divide’. © 2023 The Autho

The C-word: how critical cartography, critical GIS and critical data studies can repoliticise disaster-related maps

Purpose: Mapping and Geographic Information Systems (GIS) are widely used in disaster research and practice. While, in some cases, these practices incorporate methods inspired by critical cartography and critical GIS, they rarely engage with the theoretical discussions that animate those fields.Design/methodology/approach: In this commentary, the author considers three such discussions, and draws out their relevance for disaster studies: the turn towards processual cartographies, political economy analysis of datafication and calls for theorising computing of and from the South.Findings: The review highlights how these discussions can contribute to the work of scholars engaged in mapping for disaster risk management and research. First, it can counter the taken-for-granted nature of disaster-related maps, and encourage debate about how such maps are produced, used and circulated. Second, it can foster a reflexive attitude towards the urge to quantify and map disasters. Third, it can help to rethink the role of digital technologies with respect to ongoing conversations on the need to decolonise disaster studies.Originality/value: The paper aims to familiarise disaster studies scholars with literature that has received relatively little attention in this field and, by doing so, contribute to a repoliticisation of disaster-related maps

Barium and Yttrium abundance in intermediate-age and old open clusters

Barium is a neutron capture element, that, in open clusters, is frequently over-abundant with respect to the Iron. A clear explanation for this is still missing. Additionally, its gradient across the Galactic disk is poorly constrained. We measure the abundance of yttrium and barium using the synthetic spectrum method from UVES high-resolution spectra of eight distant open clusters, namely Ruprecht 4, Ruprecht 7, Berkeley 25, Berkeley 73, Berkeley 75, NGC 6192, NGC 6404, and NGC 6583. The barium abundance was estimated using NLTE approximation. We confirm that Barium is indeed over-abundant in most clusters, especially young clusters. Finally, we investigated the trend of yttrium and barium abundances as a function of distance in the Galaxy and ages. Several scenarios for the barium over-abundance are then discussed.Comment: 9 pages, 10 figure

On the subject of the Ba overabundance in the open clusters stars

For eight distant open clusters, namely Ruprecht 4, Ruprecht 7, Berkeley 25, Berkeley 73, Berkeley 75, NGC 6192, NGC 6404, and NGC 6583, we determined the yttrium and barium abundances using the UVES, VLT spectra (ESO, Chile). The stars of one young cluster (Ruprecht 7) demonstrate significant barium overabundance( 3c0.55 dex) that can not be due to the determination error. We have considered the Ba abundance determination errors due to LTE approach, saturation of the lines, synthetic and observed barium line fitting, and the causes of the Ba overabundance associated with the Galactic disc enrichment or the origin of open clusters. Possible explanation for this overabundance can be the origin of n-capture elements enrichment of the clusters (galactic or extragalactic) or additional sources of the Ba production

The Magellanic Bridge cluster NGC 796: Deep optical AO imaging reveals the stellar content and initial mass function of a massive open cluster

NGC 796 is a massive young cluster located 59 kpc from us in the diffuse intergalactic medium of the 1/5-1/10 $Z_{\odot}$ Magellanic Bridge, allowing to probe variations in star formation and stellar evolution processes as a function of metallicity in a resolved fashion, providing a link between resolved studies of nearby solar-metallicity and unresolved distant metal-poor clusters located in high-redshift galaxies. In this paper, we present adaptive optics $gri$H$\alpha$ imaging of NGC 796 (at 0.5", which is ~0.14 pc at the cluster distance) along with optical spectroscopy of two bright members to quantify the cluster properties. Our aim is to explore if star formation and stellar evolution varies as a function of metallicity by comparing the properties of NGC 796 to higher metallicity clusters. We find from isochronal fitting of the cluster main sequence in the colour-magnitude diagram an age of 20$^{+12}_{-5}$ Myr. Based on the cluster luminosity function, we derive a top-heavy stellar initial mass function (IMF) with a slope $\alpha$ = 1.99$\pm$0.2, hinting at an metallicity and/or environmental dependence of the IMF which may lead to a top-heavy IMF in the early Universe. Study of the H$\alpha$ emission line stars reveals that Classical Be stars constitute a higher fraction of the total B-type stars when compared with similar clusters at greater metallicity, providing some support to the chemically homogeneous theory of stellar evolution. Overall, NGC 796 has a total estimated mass of 990$\pm200$ $M_{\odot}$, and a core radius of 1.4$\pm$0.3 pc which classifies it as a massive young open cluster, unique in the diffuse interstellar medium of the Magellanic Bridge.Comment: Accepted for publication in the Astrophysical Journal. Contains 14 pages, 11 figures, and 3 table

National Human Rights Institutions: Independent actors in global human rights governance?

Security and Global Affair

Binary open clusters in the Milky Way: photometric and spectroscopic analysis of NGC 5617 and Trumpler 22

Using photometry and high resolution spectroscopy we investigate for the first time the physical connection between the open clusters NGC 5617 and Trumpler 22. Based on new CCD photometry we report their spatial proximity and common age of ~70 Myr. Based on high resolution spectra collected using the HERMES and UCLES spectrographs on the Anglo-Australian telescope, we present radial velocities and abundances for Fe, Na, Mg, Al, Si, Ca and Ni. The measured radial velocities are -38.63 +/-2.25 km/s for NGC 5617 and -38.46 +/-2.08 km/s for Trumpler 22. The mean metallicity of NGC 5617 was found to be [Fe/H] =-0.18 +/-0.02 and for Trumpler 22 was found to be [Fe/H] = -0.17 +/-0.04. The two clusters share similar abundances across the other elements, indicative of a common chemical enrichment history of these clusters. Together with common motions and ages we confirm that NGC 5617 and Trumpler 22 are a primordial binary cluster pair in the Milky Way.Comment: 7 pages, 3 figure, accepted by MNRA

Model-Independent Diagnostics of Highly Reddened Milky Way Star Clusters: Age Calibration

The next generation near- and mid-infrared Galactic surveys will yield a large number of new highly obscured star clusters. Detailed characterization of these new objects with spectroscopy is time-consuming. Diagnostic tools that will be able to characterize clusters based only on the available photometry will be needed to study large samples of the newly found objects. The brightness difference between the red clump and the main-sequence turn-off point have been used as a model-independent age calibrator for clusters with ages from a few 10$^8$ to 10$^{10}$ yr in the optical. Here we apply for the first time the method in the near-infrared. We calibrated this difference in $K$-band, which is likely to be available for obscured clusters, and we apply it to a number of test clusters with photometry comparable to the one that will be yielded by the current or near-future surveys. The new calibration yields reliable ages over the range of ages for which the red clump is present in clusters. The slope of the relation is smoother than that of the corresponding $V$-band relation, reducing the uncertainty in the age determinations with respect to the optical ones.Comment: 5 pages, 5 eps figure, accepted for publication in Astronomy and Astrophysic

Professor Ugo Carraro and BAM: two friends for life

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