123 research outputs found
The Effect of Columnar Disorder on the Superconducting Transition of a Type-II Superconductor in Zero Applied Magnetic Field
We investigate the effect of random columnar disorder on the superconducting
phase transition of a type-II superconductor in zero applied magnetic field
using numerical simulations of three dimensional XY and vortex loop models. We
consider both an unscreened model, in which the bare magnetic penetration
length is approximated as infinite, and a strongly screened model, in which the
magnetic penetration length is of order the vortex core radius. We consider
both equilibrium and dynamic critical exponents. We show that, as in the
disorder free case, the equilibrium transitions of the unscreened and strongly
screened models lie in the same universality class, however scaling is now
anisotropic. We find for the correlation length exponent , and
for the anisotropy exponent . We find different dynamic
critical exponents for the unscreened and strongly screened models.Comment: 30 pages 12 ps figure
Author Correction: COVIDiSTRESS diverse dataset on psychological and behavioural outcomes one year into the COVID-19 pandemic
This is the final version. Available on open access from Nature Research via the DOI in this record. The article to which this is the author correction is available in ORE at http://hdl.handle.net/10871/132443The original version of this Article contained an error in the spelling of the author Krzysztof Hanusz, which was incorrectly given as Hanusz Krzysztof. This has now been corrected in both the PDF and HTML versions of the Article
COVIDiSTRESS diverse dataset on psychological and behavioural outcomes one year into the COVID-19 pandemic
This is the final version. Available on open access from Nature Research via the DOI in this record. Code availability:
The data cleaning notebook and list of variables can be obtained freely here: https://doi.org/10.17605/OSF.
IO/36TSD31. The data was imported and cleaned using the R software qualtRics, data.table, tidyverse, and
multicon. Before analysing the data, it should be noted that invalid cases were excluded and the response options
for some variables were recoded to numeric values measuring the degree of agreement (see data cleaning above
for details). In some of these options, a neutral value was added to the response options and scored in two different
ways. For data quality reasons, we also employed an attention check and filtered data in regard to this check.The author correction to this article is available in ORE at http://hdl.handle.net/10871/132444During the onset of the COVID-19 pandemic, the COVIDiSTRESS Consortium launched an open-access global survey to understand and improve individuals' experiences related to the crisis. A year later, we extended this line of research by launching a new survey to address the dynamic landscape of the pandemic. This survey was released with the goal of addressing diversity, equity, and inclusion by working with over 150 researchers across the globe who collected data in 48 languages and dialects across 137 countries. The resulting cleaned dataset described here includes 15,740 of over 20,000 responses. The dataset allows cross-cultural study of psychological wellbeing and behaviours a year into the pandemic. It includes measures of stress, resilience, vaccine attitudes, trust in government and scientists, compliance, and information acquisition and misperceptions regarding COVID-19. Open-access raw and cleaned datasets with computed scores are available. Just as our initial COVIDiSTRESS dataset has facilitated government policy decisions regarding health crises, this dataset can be used by researchers and policy makers to inform research, decisions, and policy.US Department of Education Developing Hispanic-Serving Institutions ProgramTexas A&M International University (TAMIU)HSE University, R
Examining the role of Donald Trump and his supporters in the 2021 assault on the U.S. Capitol: A dual-agency model of identity leadership and engaged followership
This paper develops a dual-agency model of leadership which treats collective phenomena as a co-production between leaders and followers. The model integrates work on identity leadership and engaged followership derived from the social identity tradition in social psychology. In contrast to binary models in which leaders or followers are seen to have agency, this argues that leaders gain influence by framing the agency of their followers and defining the parameters of their action but leaving space for creativity in how their goals are accomplished. Followers in turn, exhibit their loyalty and attachment to the leader by competing to be most effective in advancing these goals. We illustrate the model by drawing on a range of sources, most notably the events of 6th January 2021 when Donald Trump’s exhortations to his supporters that they should ‘fight’ to ‘stop the steal’ of the 2020 election was followed by an attack on the Capitol. We argue that it is Trump’s willing participation in this mutual process of identity enactment, rather than any instructions which may (or may not) have been contained in his speech, that should be the basis for assessing his influence on, and responsibility for, the assault.</p
Exact results on the Kitaev model on a hexagonal lattice: spin states, string and brane correlators, and anyonic excitations
In this work, we illustrate how a Jordan-Wigner transformation combined with
symmetry considerations enables a direct solution of Kitaev's model on the
honeycomb lattice. We (i) express the p-wave type fermionic ground states of
this system in terms of the original spins, (ii) adduce that symmetry alone
dictates the existence of string and planar brane type correlators and their
composites, (iii) compute the value of such non-local correlators by employing
the Jordan-Wigner transformation, (iv) affirm that the spectrum is
inconsequential to the existence of topological quantum order and that such
information is encoded in the states themselves, and (v) express the anyonic
character of the excitations in this system and the local symmetries that it
harbors in terms of fermions.Comment: 14 pages, 7 figure
Vortex glass transition in a random pinning model
We study the vortex glass transition in disordered high temperature
superconductors using Monte Carlo simulations. We use a random pinning model
with strong point-correlated quenched disorder, a net applied magnetic field,
longrange vortex interactions, and periodic boundary conditions. From a finite
size scaling study of the helicity modulus, the RMS current, and the
resistivity, we obtain critical exponents at the phase transition. The new
exponents differ substantially from those of the gauge glass model, but are
consistent with those of the pure three-dimensional XY model.Comment: 7 pages RevTeX, 4 eps figure
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COVIDiSTRESS diverse dataset on psychological and behavioural outcomes one year into the COVID-19 pandemic
During the onset of the COVID-19 pandemic, the COVIDiSTRESS Consortium launched an open-access global survey to understand and improve individuals’ experiences related to the crisis. A year later, we extended this line of research by launching a new survey to address the dynamic landscape of the pandemic. This survey was released with the goal of addressing diversity, equity, and inclusion by working with over 150 researchers across the globe who collected data in 48 languages and dialects across 137 countries. The resulting cleaned dataset described here includes 15,740 of over 20,000 responses. The dataset allows cross-cultural study of psychological wellbeing and behaviours a year into the pandemic. It includes measures of stress, resilience, vaccine attitudes, trust in government and scientists, compliance, and information acquisition and misperceptions regarding COVID-19. Open-access raw and cleaned datasets with computed scores are available. Just as our initial COVIDiSTRESS dataset has facilitated government policy decisions regarding health crises, this dataset can be used by researchers and policy makers to inform research, decisions, and policy
Domain Wall Renormalization Group Study of XY Model with Quenched Random Phase Shifts
The XY model with quenched random disorder is studied by a zero temperature
domain wall renormalization group method in 2D and 3D. Instead of the usual
phase representation we use the charge (vortex) representation to compute the
domain wall, or defect, energy. For the gauge glass corresponding to the
maximum disorder we reconfirm earlier predictions that there is no ordered
phase in 2D but an ordered phase can exist in 3D at low temperature. However,
our simulations yield spin stiffness exponents in 2D
and in 3D, which are considerably larger than
previous estimates and strongly suggest that the lower critical dimension is
less than three. For the XY spin glass in 3D, we obtain a spin
stiffness exponent which supports the existence of
spin glass order at finite temperature in contrast with previous estimates
which obtain . Our method also allows us to study
renormalization group flows of both the coupling constant and the disorder
strength with length scale . Our results are consistent with recent analytic
and numerical studies suggesting the absence of a re-entrant transition in 2D
at low temperature. Some possible consequences and connections with real vortex
systems are discussed.Comment: 14 pages, 9 figures, revtex
Tweeting about sexism motivates further activism: A social identity perspective
Women, more so than men, are using social media activism to respond to sexism. However, when they do, they are also faced with gendered criticisms (\u27hashtag feminism\u27) that may instead serve to silence them. Based in social identity theory, this research examined how women\u27s social media activism, in response to sexism, may be a first step toward further activism. Two studies used a simulated Twitter paradigm to expose women to sexism and randomly assigned them to either tweet in response, or to a no-tweet control condition. Both studies found support for a serial mediation model such that tweeting after sexism strengthened social identity, which in turn increased collective action intentions, and in turn, behavioural collective actions. Study 2 further showed that validation from others increases the indirect effect of tweeting on behavioural collective action through collective action intentions, but group efficacy did not moderate any indirect effects. It was concluded that when social media activism in response to sexism promotes an enactment of women’s social identity, thereby mobilizing them to further action
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