Evidence for the Role of Instantons in Hadron Structure from Lattice QCD

Cooling is used as a filter on a set of gluon fields sampling the Wilson action to selectively remove essentially all fluctuations of the gluon field except for the instantons. The close agreement between quenched lattice QCD results with cooled and uncooled configurations for vacuum correlation functions of hadronic currents and for density-density correlation functions in hadronic bound states provides strong evidence for the dominant role of instantons in determining light hadron structure and quark propagation in the QCD vacuum.Comment: 26 pages in REVTeX, plus 10 figures, uuencoded. Submitted to Physical Review D. MIT-CTP-226

Pion structure from improved lattice QCD: form factor and charge radius at low masses

The charge form factor of the pion is calculated in lattice QCD. The non-perturbatively improved Sheikholeslami-Wohlert action is used together with the $\mathcal{O}(a)$ improved vector current. Other choices for the current are examined. The form factor is extracted for pion masses from 970 MeV down to 360 MeV and for momentum transfers $Q^2 \leq 2 \mathrm{GeV}^2$. The mean square charge radius is extracted, compared to previous determinations and its extrapolation to lower masses discussed.Comment: 12 pages REVTeX, 15 figures. Designation of currents clarified. Details concerning extraction of parameters added. Version accepted by Phys. Rev.

Trialling technologies to reduce hospital in‐patient falls: an agential realist analysis

This paper analyses the 'failure' of a patient safety intervention. Our study was part of an RCT of bed and bedside chair pressure sensors linked to radio pagers to prevent bedside falls in older people admitted to hospital. We use agential realism within science and technology studies to examine the fall and its prevention as a situated phenomenon of knowledge that is made and unmade through intra-actions between environment, culture, humans and technologies. We show that neither the intervention (the pressure sensor system), nor the outcome (fall prevention) could be disentangled from the broader sociomaterial context of the ward, the patients, the nurses and (especially) their work through the RCT. We argue that the RCT design, by virtue of its unacknowledged assumptions, played a part in creating the negative findings. The study also raises wider questions about the kind of subjectivities, agencies and power relations these entanglements might effect and (re)produce in the hospital ward

The Strongly Coupled 't Hooft Model on the Lattice

We study the strong coupling limit of the one-flavor and two-flavor massless 't Hooft models, $large-{\cal N}_c$-color $QCD_2$, on a lattice. We use staggered fermions and the Hamiltonian approach to lattice gauge theories. We show that the one-flavor model is effectively described by the antiferromagnetic Ising model, whose ground state is the vacuum of the gauge model in the infinite coupling limit; expanding around this ground state we derive a strong coupling expansion and compute the lowest lying hadron masses as well as the chiral condensate of the gauge theory. Our lattice computation well reproduces the results of the continuum theory. Baryons are massless in the infinite coupling limit; they acquire a mass already at the second order in the strong coupling expansion in agreement with the Witten argument that baryons are the $QCD$ solitons. The spectrum and chiral condensate of the two-flavor model are effectively described in terms of observables of the quantum antiferromagnetic Heisenberg model. We explicitly write the lowest lying hadron masses and chiral condensate in terms of spin-spin correlators on the ground state of the spin model. We show that the planar limit (${\cal N}_c\longrightarrow \infty$) of the gauge model corresponds to the large spin limit ($S\longrightarrow \infty$) of the antiferromagnet and compute the hadron mass spectrum in this limit finding that, also in this model, the pattern of chiral symmetry breaking of the continuum theory is well reproduced on the lattice.Comment: LaTex, 25 pages, no figure

Sociomateriality Implications of Software As a Service Adoption on IT-workers’ Roles and Changes in Organizational Routines of IT Systems Support

This paper aims to deepen our understanding on how sociomateriality practices influence IT workers’ roles and skill set requirements and changes to the organizational routines of IT systems support, when an organization migrates an on-premise IT system to a software as a service (SaaS) model. This conceptual paper is part of an ongoing study investigating organizations that migrated on-premise IT email systems to SaaS business models, such as Google Apps for Education (GAE) and Microsoft Office 365 systems, in New Zealand tertiary institutions. We present initial findings from interpretive case studies. The findings are, firstly, technological artifacts are entangled in sociomaterial practices, which change the way humans respond to the performative aspects of the organizational routines. Human and material agencies are interwoven in ways that reinforce or change existing routines. Secondly, materiality, virtual realm and spirit of the technology provide elementary levels at which human and material agencies entangle. Lastly, the elementary levels at which human and material entangle depends on the capabilities or skills set of an individual

Technology and Sociomaterial Performation

Part 1: IS/IT Implementation and AppropriationInternational audienceOrganizational researchers have acknowledged that understanding the relationship between technology and organization is crucial to understanding modern organizing and organizational change [1]. There has been a significant amount of debate concerning the theoretical foundation of this relationship. Our research draws and extends Deleuze and DeLanda’s work on assemblages and Callon’s concept of performation to investigate how different sociomaterial practices are changed and stabilized after the implementation of new technology. Our findings from an in-depth study of two ambulatory clinics within a hospital system indicate that “perform-ing” of constituting, counter-performing, calibrating, and stratifying explained the process of sociomaterial change and that this process is governed by an overarching principle of “performative exigency”. Future studies on sociomateriality and change may benefit from a deeper understanding of how sociomaterial assemblages are rendered performative

Re-Generating Research Partnerships in Early Childhood Education: A Non-Idealized Vision

This chapter provides a challenge to positivist notions of partnership in early childhood education, and instead proposes a re-generative posthumanist perspective, based on relationality of partnerships. Specifically, the chapter addresses the troubles and struggles inherited in research partnerships through a non-idealized vision of research partnerships. It experiments with the notions of regenerating ‘change’ and regenerating ‘relationality’. It also addresses the multi-layered aspects of knowledge-in-the-making; non-innocent relations; difficulties of thinking change in research; and the potentialities of conflict and dissension. However, no certainties and closures about research partnerships are provided

Biggish Data: Friedrich Engels, Material Ecology, and Victorian Data

Through Friedrich Engels’ The Condition of the Working Class in England (1845), this article examines two prominent themes in environmental humanities – vital ecological materialism and ‘big data’. Engels’ vivid descriptions of factories, houses, and environment shared the central tenets of ‘material ecology’ – ‘thing power’ (Jane Bennett); ‘intra-actions’ of social and material agency (Karen Barad); ‘trans-corporeality’ (Stacy Alaimo) – and met Bennett’s call to align vital and historical materialism. The main body of the paper connects his analysis both to current debates about integrating ‘big data’ into social science and the humanities and to comparable nineteenth-century developments in statistics and data visualisation. Engels articulated the working-class condition by blending four distinct modes of investigation: big data; qualitative survey research; literary thick description; and theory (the nascent critique of capitalist political economy). Such a mix remains rich with possibilities for sociology and humanities not only in communicating but in generating knowledge about complex ecologies

Touch and contact during COVID-19:Insights from queer digital spaces

The aim of this conceptual paper is to discuss the transformation of socialisation processes due to the digitalisation of entertainment and community formation during COVID-19. More specifically, we focus on alternative modes of touch and contact within the context of queer digital entertainment spaces and question how the world is shaped and sensed in a (post-) COVID-19 era. Inspired by the work of Karen Barad on a quantum theory of queer intimacies, we highlight that the rise of hybridised experiences in-between physical and digital spaces captures a series of spatio-temporal, material and symbolic dimensions of touch and contact. We conclude by drawing implications for the future of organisations and work

Is a posthumanist bildung possible? Reclaiming the promise of bildung for contemporary higher education

My central argument in this article is that the notion of Bildung may offer conceptual sustenance to those who wish to develop educative practices to supplement or contest the prevalence and privileging of market and economic imperatives in higher education, which configure teaching and learning as an object available to measurement. I pursue this argument by making the case for an ethical posthuman Bildung which recognises the inseparability of knowing and being, the materiality of educative relations, and the need to install an ecology of ethical relations at the centre of educational practice in higher education. Such a re-conceptualisation situates Bildung not purely as an individual goal but as a process of ecologies and relationships. The article explores Bildung as a flexible concept, via three theoretical lenses, and notes that it has always been subject to continuing revision in response to changing social and educational contexts. In proposing the possibility of, and need for, a posthuman Bildung, the articles offers a critical review of the promise of Bildung and outlines some of the radical ways that a posthuman Bildung might reinvigorate conceptualisations of contemporary higher education. Keywords : Bildung; posthumanism; higher education; ethics; ecology