Style over substance: A psychologically informed approach to feature selection and generalisability for author classification

Data availability: Data will be made available on request.Copyright © 2023 The Authors. Author profiling, or classifying user generated content based on demographic or other personal attributes, is a key task in social media-based research. Whilst high-accuracy has been achieved on many attributes, most studies tend to train and test models on a single domain only, ignoring cross-domain performance and research shows that models often transfer poorly into new domains as they tend to depend heavily on topic-specific (i.e., lexical) features. Knowledge specific to the field (e.g., Psychology, Political Science) is often ignored, with a reliance on data driven algorithms for feature development and selection. Focusing on political affiliation, we evaluate an approach that selects stylistic features according to known psychological correlates (personality traits) of this attribute. Training data was collected from Reddit posts made by regular users of the political subreddits of r/republican and r/democrat. A second, non-political dataset, was created by collecting posts by the same users but in different subreddits. Our results show that introducing domain specific knowledge in the form of psychologically informed stylistic features resulted in better out of training domain performance than lexical or more commonly used stylistic features

‘Let us teach our children’: Online racism and everyday far-right ideologies on TikTok

Copyright © 2023 The Author(s). This paper identifies perceptions of injustice, grievance, and alienation as online drivers of radicalisation by concentrating on contemporary visual radicalisation patterns. It focuses on far-right agents of radicalisation in the UK with a particular analysis of visual and ephemeral drivers of radicalisation on social media platforms. We analysed widespread TikTok hashtags which embody mainstream right-wing ideologies. Using these hashtags, we selected four popular videos (> 30k views) for visual thematic analysis of their compositional content and comment-sphere to explore everyday representations and discourses of far-right ideologies. Our findings highlight mundane online expressions on TikTok that collectively reinforce notions of a shared idealised identity built on nostalgic reinterpretations of an imperial past, which contribute to the mainstreaming of far-right ideas and ideologies.This research was part of the project entitled “De-Radicalisation in Europe and Beyond: Detect, Resolve, Re-integrate”, funded by Horizon 2020 Research and Innovation Framework Programme [grant number 959198]

‘Let us teach our children’: online racism and everyday far-right ideologies on TikTok

This paper identifies perceptions of injustice, grievance, and alienation as online drivers of radicalisation by concentrating on contemporary visual radicalisation patterns. It focuses on far-right agents of radicalisation in the UK with a particular analysis of visual and ephemeral drivers of radicalisation on social media platforms. We analysed widespread TikTok hashtags which embody mainstream right-wing ideologies. Using these hashtags, we selected four popular videos (> 30k views) for visual thematic analysis of their compositional content and comment-sphere to explore everyday representations and discourses of far-right ideologies. Our findings highlight mundane online expressions on TikTok that collectively reinforce notions of a shared idealised identity built on nostalgic reinterpretations of an imperial past, which contribute to the mainstreaming of far-right ideas and ideologies

The “Roll and Lock” Mechanism of Force Generation in Muscle

SummaryMuscle force results from the interaction of the globular heads of myosin-II with actin filaments. We studied the structure-function relationship in the myosin motor in contracting muscle fibers by using temperature jumps or length steps combined with time-resolved, low-angle X-ray diffraction. Both perturbations induced simultaneous changes in the active muscle force and in the extent of labeling of the actin helix by stereo-specifically bound myosin heads at a constant total number of attached heads. The generally accepted hypothesis assumes that muscle force is generated solely by tilting of the lever arm, or the light chain domain of the myosin head, about its catalytic domain firmly bound to actin. Data obtained suggest an additional force-generating step: the “roll and lock” transition of catalytic domains of non-stereo-specifically attached heads to a stereo-specifically bound state. A model based on this scheme is described to quantitatively explain the data

FRET characterisation for cross-bridge dynamics in single-skinned rigor muscle fibres

In this work we demonstrate for the first time the use of Förster resonance energy transfer (FRET) as an assay to monitor the dynamics of cross-bridge conformational changes directly in single muscle fibres. The advantage of FRET imaging is its ability to measure distances in the nanometre range, relevant for structural changes in actomyosin cross-bridges. To reach this goal we have used several FRET couples to investigate different locations in the actomyosin complex. We exchanged the native essential light chain of myosin with a recombinant essential light chain labelled with various thiol-reactive chromophores. The second fluorophore of the FRET couple was introduced by three approaches: labelling actin, labelling SH1 cysteine and binding an adenosine triphosphate (ATP) analogue. We characterise FRET in rigor cross-bridges: in this condition muscle fibres are well described by a single FRET population model which allows us to evaluate the true FRET efficiency for a single couple and the consequent donor–acceptor distance. The results obtained are in good agreement with the distances expected from crystallographic data. The FRET characterisation presented herein is essential before moving onto dynamic measurements, as the FRET efficiency differences to be detected in an active muscle fibre are on the order of 10–15% of the FRET efficiencies evaluated here. This means that, to obtain reliable results to monitor the dynamics of cross-bridge conformational changes, we had to fully characterise the system in a steady-state condition, demonstrating firstly the possibility to detect FRET and secondly the viability of the present approach to distinguish small FRET variations

Development of an optogenetic toolkit for neural circuit dissection in squirrel monkeys

Optogenetic tools have opened a rich experimental landscape for understanding neural function and disease. Here, we present the first validation of eight optogenetic constructs driven by recombinant adeno-associated virus (AAV) vectors and a WGA-Cre based dual injection strategy for projection targeting in a widely-used New World primate model, the common squirrel monkey Saimiri sciureus. We observed opsin expression around the local injection site and in axonal projections to downstream regions, as well as transduction to thalamic neurons, resembling expression patterns observed in macaques. Optical stimulation drove strong, reliable excitatory responses in local neural populations for two depolarizing opsins in anesthetized monkeys. Finally, we observed continued, healthy opsin expression for at least one year. These data suggest that optogenetic tools can be readily applied in squirrel monkeys, an important first step in enabling precise, targeted manipulation of neural circuits in these highly trainable, cognitively sophisticated animals. In conjunction with similar approaches in macaques and marmosets, optogenetic manipulation of neural circuits in squirrel monkeys will provide functional, comparative insights into neural circuits which subserve dextrous motor control as well as other adaptive behaviors across the primate lineage. Additionally, development of these tools in squirrel monkeys, a well-established model system for several human neurological diseases, can aid in identifying novel treatment strategies

The psychic life of fragments: splitting from Ferenczi to Klein

The present paper starts from the reflection that there is a curious “phenomenological gap” in psychoanalysis when it comes to processes of splitting and to describing the “life” of psychic fragments resulting from processes of splitting. In simpler terms, we are often in a position to lack a precise understanding of what is being split and how the splitting occurs. I argue that although Melanie Klein’s work is often engaged when talking of splitting (particularly through discussions on identification, projection and projective identification), there are some important phenomenological opacities in her construction. I show that by orchestrating a dialogue between Melanie Klein and Sándor Ferenczi, we arrive at a fuller and more substantive conception of psychic splitting and of the psychic life of fragments which are the result of splitting. This is even more meaningful because there are some unacknowledged genealogical connections between Ferenczian concepts and Kleinian concepts, which I here explore. While with Klein we remain in the domain of “good” and “bad” objects—polarised objects which are constantly split and projected—with Ferenczi we are able to also give an account of complicated forms of imitation producing psychic fragments and with a “dark” side of identification, which he calls “identification with the aggressor”. While attempting to take steps toward imagining a dialogue between Klein and Ferenczi, I note a certain silent “Ferenczian turn” in a late text by Melanie Klein, “On the Development of Mental Functioning”, written in 1958. In particular, I reflect on her reference to some “terrifying figures” of the psyche, which cannot be accounted for simply as the persecutory parts of the super-ego but are instead more adequately read as more enigmatic and more primitive psychic fragments, resulting from processes of splitting