'Wanna trade?': Cisheteronormative homosocial masculinity and the normalization of abuse in youth digital sexual image exchange

This paper draws upon a qualitative study with 144 young people in seven different research schools in England, exploring how cis-heteronormative homosocial masculinity practices shape digital sexual image exchange. We examine three types of practices: 1) boys asking girls for nudes (pressurized sexting, which we position as online sexual harassment); 2) transactional nude solicitation (boys sending dick pics and asking girls for nudes, which we position as image based sexual harassment and cyberflashing); 3) non-consensual sharing of girls and boys nude images (which we position as image based sexual abuse, showing the differential impacts with lasting sexual stigma worse for girls). Our findings confirm earlier research that demonstrated homosocial masculinity currency is gained via the non-consensual sharing of images of girls’ bodies. We also investigate the more recent rise of male nudes (dick pics) and how a homosocial culture of humour and lad banter tends to lessen the sexual stigmatization of leaked dick pics. We argue providing boys with time and space to reflect on homosocial masculinity performances is crucial for disrupting these practices and our conclusions outline new UK school guidance for tackling online sexual harassment, cyberflashing and image-based sexual abuse

Teen Girls' Experiences Negotiating the Ubiquitous Dick Pic: Sexual Double Standards and the Normalization of Image Based Sexual Harassment

A range of important studies have recently explored adult women’s experiences of receiving unwanted dick pics (Amundsen, 2020). However, to date there has been limited research that has explored teen girls’ experiences of receiving unwanted penis images in depth. To address this gap we draw upon our findings from a qualitative study using focus group interviews and arts based drawing methods to explore social media image sharing practices with 144 young people aged 11–18 in seven secondary schools in England. We argue that being bombarded with unwanted dick pics on social media platforms like Snapchat normalises harassing practices as signs of desirability and popularity for girls, but suggest that being sent unsolicited dick pics from boys at school is more difficult for girls to manage or report than ignoring or blocking random older senders. We also found that due to sexual double standards girls were not able to leverage dick pics for status in the same way boys can use girls’ nudes as social currency, since girls faced the possibility of being shamed for being known recipients of dick pics. Finally we explore how some girls challenge abusive elements of toxic masculinity in the drawing sessions and our conclusion argues that unwanted dick pics should always be understood as forms of image based sexual harassment

Theory of Linear Spin Wave Emission from a Bloch Domain Wall

We report an analytical theory of linear emission of exchange spin waves from a Bloch domain wall, excited by a uniform microwave magnetic field. The problem is reduced to a one-dimensional Schr\"odinger-like equation with a P\"oschl-Teller potential and a driving term of the same profile. The emission of plane spin waves is observed at excitation frequencies above a threshold value, as a result of a linear process. The height-to-width aspect ratio of the P\"oschl-Teller profile for a domain wall is found to correspond to a local maximum of the emission efficiency. Furthermore, for a tailored P\"oschl-Teller potential with a variable aspect ratio, particular values of the latter can lead to enhanced or even completely suppressed emission.Comment: added ancillary file

Non-Hausdorff Symmetries of C*-algebras

Symmetry groups or groupoids of C*-algebras associated to non-Hausdorff spaces are often non-Hausdorff as well. We describe such symmetries using crossed modules of groupoids. We define actions of crossed modules on C*-algebras and crossed products for such actions, and justify these definitions with some basic general results and examples.Comment: very minor changes. To appear in Math. An

Primitive Words, Free Factors and Measure Preservation

Let F_k be the free group on k generators. A word w \in F_k is called primitive if it belongs to some basis of F_k. We investigate two criteria for primitivity, and consider more generally, subgroups of F_k which are free factors. The first criterion is graph-theoretic and uses Stallings core graphs: given subgroups of finite rank H \le J \le F_k we present a simple procedure to determine whether H is a free factor of J. This yields, in particular, a procedure to determine whether a given element in F_k is primitive. Again let w \in F_k and consider the word map w:G x G x ... x G \to G (from the direct product of k copies of G to G), where G is an arbitrary finite group. We call w measure preserving if given uniform measure on G x G x ... x G, w induces uniform measure on G (for every finite G). This is the second criterion we investigate: it is not hard to see that primitivity implies measure preservation and it was conjectured that the two properties are equivalent. Our combinatorial approach to primitivity allows us to make progress on this problem and in particular prove the conjecture for k=2. It was asked whether the primitive elements of F_k form a closed set in the profinite topology of free groups. Our results provide a positive answer for F_2.Comment: This is a unified version of two manuscripts: "On Primitive words I: A New Algorithm", and "On Primitive Words II: Measure Preservation". 42 pages, 14 figures. Some parts of the paper reorganized towards publication in the Israel J. of Mat

Tangled Nature: A model of emergent structure and temporal mode among co-evolving agents

Understanding systems level behaviour of many interacting agents is challenging in various ways, here we'll focus on the how the interaction between components can lead to hierarchical structures with different types of dynamics, or causations, at different levels. We use the Tangled Nature model to discuss the co-evolutionary aspects connecting the microscopic level of the individual to the macroscopic systems level. At the microscopic level the individual agent may undergo evolutionary changes due to mutations of strategies. The micro-dynamics always run at a constant rate. Nevertheless, the system's level dynamics exhibit a completely different type of intermittent abrupt dynamics where major upheavals keep throwing the system between meta-stable configurations. These dramatic transitions are described by a log-Poisson time statistics. The long time effect is a collectively adapted of the ecological network. We discuss the ecological and macroevolutionary consequences of the adaptive dynamics and briefly describe work using the Tangled Nature framework to analyse problems in economics, sociology, innovation and sustainabilityComment: Invited contribution to Focus on Complexity in European Journal of Physics. 25 page, 1 figur

Mechanical Design of Long Reach Super Thin Discrete Manipulator for Inspections in Fragile Historical Environments

Long reach and small diameter manipulators are ideal for borehole deployments into search and rescue scenarios and fragile historical environments. Small diameter passageways impose constraints on a snake arm manipulator which severely limit its performance and capabilities. This work investigates the effects of tendon tensions on the maximum working length of a snake arm under tight size constraints and how the maximum length is achieved through an algorithmic approach and consideration of how and when key parts fail