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Structure and chronology of a star dune at Erg Chebbi, Morocco, reveals why star dunes are rarely recognised in the rock record
Get PDFStar dunes are the tallest dunes on Earth and are amongst the larger and more spectacular aeolian landforms. Although they are widespread in modern sandy deserts, star dunes are rarely recognised in the rock record probably due to a lack of suitable sedimentary models. This paper presents a new sedimentary model for the structure of a star dune at Erg Chebbi in Morocco (Sahara Desert) on the basis of ground-penetrating radar (GPR) surveys. Individual sedimentary structures in star dunes are
similar to those in linear or barchanoid dunes, likely leading to misidentification in the rock record. However, the suite of features described in this paper will permit identification of star dunes in future studies of the rock record. Optically stimulated luminescence (OSL) dating shows that accumulation of the Erg Chebbi star dune post-dates the end of the African Humid Period (AHP). At the base of the dune, there is an ~8000-year hiatus in the record. Since then, the dune has grown rapidly to create a 100 m high dune within the past 1000 years and is migrating towards the west. Changes in the cross-strata support the idea that star dune construction was accompanied by a change in the wind directions
‘Conspiracy theories should be called spoiler alerts’: Conspiracy, coronavirus and affective community on Russell Brand’s YouTube comment section
No full textThis article examines how conspiracy theories anchor affective communities through an analysis of the YouTube comment section for the actor and comedian turned political influencer, Russell Brand. Comparing videos before and after Brand’s shift to covid scepticism, I explore like counts, reply networks and other commenting patterns in a dataset of 217,157 comments and conduct an in-depth analysis of 2000 top comments. The findings show first, a shift towards right-wing viewpoints; second, a reduction in comment length and comment replies alongside an increase in likes; third, a sharp rise in proclamations of Brand fandom; and fourth, a steep increase in references to conspiracy. The in-depth analysis reveals that comments focused not on narrating the content of conspiracies but on celebrating conspiracy as the basis of a political community and as a defence against accusations of paranoia. I argue that conspiracy theories can function as formal categories that anchor affective communities
A new method for tracking the preparatory activation of target templates for visual search with high temporal precision
Get PDFEfficiently selecting task-relevant objects during visual search depends on foreknowledge of their defining characteristics, which are represented within attentional templates. These templates bias attentional processing towards template-matching sensory signals and are assumed to become anticipatorily activated prior to search display onset. However, a direct neural signal for such preparatory template activation processes has so far remained elusive.
Here, we introduce a new high-definition rapid serial probe presentation paradigm (RSPP-HD), which facilitates high temporal resolution tracking of target template activation processes in real time via monitoring of the N2pc component. In the RSPP-HD procedure, task-irrelevant probe displays are presented in rapid succession throughout the period between task-relevant search displays. The probe and search displays are homologously formed by lateralized “clouds” of coloured dots, yielding probes that occur at task-relevant locations without confounding template-guided and salience-driven attentional shifts. Target colour probes appearing at times when a corresponding target template is active should attract attention, thereby eliciting an N2pc. In a condition where new probe displays appeared every 50 ms, probe N2pcs were reliably elicited during the final 800 ms prior to search display onset, increasing in amplitude towards the end of this preparation period. Analogous temporal profiles were also observed with longer intervals between probes. These findings show that search template activation processes are transient, and that their temporal profile can be reliably monitored at high sampling frequencies with the RSPP-HD paradigm. This procedure offers a new route to approach various questions regarding the content and temporal dynamics of attentional control processes
Shaping the state from below: the rise of local petitioning in early modern England
Get PDFThe growing power and remit of the state in early modern England was shaped directly and indirectly by new developments in local petitioning. Over the course of the late sixteenth and early seventeenth centuries, county and city magistrates received rapidly growing numbers of petitions about practical matters both from individuals and from communities. The range of people involved as initiators, organisers and subscribers of petitions grew alongside this, including substantial numbers of women and poor men as well as many middling male householders. This chapter examines how local petitioning was increasingly encouraged by the reams of new statutory obligations and entitlements created from the mid-sixteenth century onwards. Especially important was the new the fiscal role of parish and county governments in dealing with various forms of poverty, but the novel licencing regime for cottages and alehouses was also significant in spurring engagement. Moreover, these developments were mirrored in how petitioners framed their requests. While traditional appeals to piety and mercy remained important, there seems to have been a growing tendency to highlight impersonal state obligations though the language of ‘law’ and ‘statute’, rather than foregrounding individual paternalist duties. Overall, this chapter shows a growing proportion of ordinary people using petitions to shape the practice of local governance, especially the redistribution of funds via rating and relief systems. They were asking for the state to fulfil its statutory duties and protect their legal rights, often with great success. The symbiotic relationship between statute law, county government and local petitioning thus helped to deepen and strengthen the structure of the English polity. It enabled and encouraged popular participation in the implementation of new policies, especially the enforcing of new fiscal rights and obligations. As such, it gave ordinary people a vital role in what we might call ‘state building from below’
Why do we do as we do? How do we know what’s best? Reflecting on the methodological challenges of measurement in initiatives using digital technologies for combatting corruption
Get PDFThis paper discusses the methodological challenges in the design of anti-corruption initiatives utilising digital technologies. In particular, the focus is on the measurement problem. Using anti-corruption initiatives as case studies, two central issues that are raised: firstly, of examining and unpacking the rationale for how digital technologies are understood (and assumed) as useful for combating corruption. Secondly, identifying motives and drivers in within these anti-corruption initiatives. As digital technology is further employed in anti-corruption initiatives, it seems a good point at present, to stop and reflect on how and why such initiatives are designed with digital technologies. The paper concludes that there is need to include greater discussion about the underlying methodological challenges around measurements. It requires more openness in terms of the principles and the system of methods used for the selection of digital technologies and connecting choice to identified objective, and the role of measurement to the objective
Facebook city: place-named groups as urban communication infrastructure in Greater London
Get PDFThis paper investigates the geography of Facebook use at an urban-regional scale, focussing on place-named groups, meaning various interest groups with names relating to places such as towns, neighbourhoods, or points of interest. Conceptualising Facebook as a digital infrastructure – that is, the platform’s urban footprint, in the form of its place-named groups, rather than what individuals share and create using the service – we explore the location, theme, and scale of 3016 groups relating to places in Greater London. Firstly, we address the quantitative and qualitative methodological challenges that we faced to identify the groups and ground them geographically. Secondly, we analyse the scale of the toponyms in the group names, which are predominantly linked to London’s suburbs. Thirdly, we study the spatial distribution of groups, both overall and by specific types, in relation to the socio-demographic characteristics of residents at the borough level. Through correlation and robust regression analyses, the presence and activity of groups are linked to a relatively older, non-deprived, and non-immigrant population living in less dense areas, with high variability across different group types. These results portray place-named Facebook groups as communication infrastructure skewed towards more banal interactions and places in Greater London’s outlying boroughs. This research is among the first to explore and visualize the urban geographies of Facebook groups at a metropolitan scale, showing the extent, nature and locational tendencies of large-scale social media use as increasingly ordinary aspects of how people come to know, experience, live and work in cities
Cortactin stabilizes actin branches by bridging activated Arp2/3 to its nucleated actin filament
Get PDFRegulation of the assembly and turnover of branched actin filament networks nucleated by the Arp2/3 complex is essential during many cellular processes including cell migration and membrane trafficking. Cortactin is important for actin branch stabilization but the mechanism by which this occurs is unclear.
Given this, we determined the structure of vertebrate cortactin-stabilized Arp2/3 actin branches using cryo-electron microscopy. We find that cortactin interacts with the new daughter filament nucleated by the Arp2/3 complex at the branch site rather than the initial mother actin filament. Cortactin preferentially binds activated Arp3. It also stabilizes the F-actin-like interface of activated Arp3 with the first actin subunit of the new filament, and its central repeats extend along successive daughter filament subunits. The preference of cortactin for activated Arp3 explains its retention at the actin branch and accounts for its synergy with other nucleation promoting factors in regulating branched actin network dynamics
What can art history offer medical humanities?
Get PDFThis article charts the emergence of visual medical humanities as a space of academic research, creative practice, and lively critical debate, with a focus on how art historical scholarship has influenced the field’s formation. Concentrating on developments over the past decade, it offers an overview of current scholarship while highlighting opportunities and challenges for the future. We begin with a survey of medical and health humanities handbooks and readers, noting that their engagement with art and visual culture is predominately limited to the contexts of therapy, clinical pedagogy, and medical history. The main part of the article explores art historical scholarship in relation to three areas of significance for the medical humanities. First, we address art historical research that engages with medical history, identifying major topoi including the anatomical body, the doctor-patient encounter, and the close relationship between clinical and artistic vision; we argue that this work has tended to presume, rather than explicitly articulate, its relationship to medical humanities, and recommend that art historians wishing to engage more deeply with the medical humanities need to clearly communicate what their work brings to wider debates in the field. Second, we explore contemporary arts practices that mobilise health-related experiences, forms of care, and practical activism: medical humanities, we argue, has much to gain from a critical engagement with contemporary (as well as historical) art. Third, we review three art-history led projects that are re-defining the field and promoting new models for collaborative “entanglement” across disciplines: Art HX: Visual and Medical Legacies of British Colonialism; Visualizing the Virus; and Confabulations: Art Practice, Art History, Critical Medical Humanities. By arguing for the vital importance of attending to the critical complexities of art and visual culture, this article aims to enrich existing debates and provoke a new wave of visually-engaged medical humanities scholarship
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