Indirect contact predicts direct contact : longitudinal evidence and the mediating role of intergroup anxiety

While the effects of direct and indirect forms of contact on intergroup relations are well documented, little is known about their longitudinal co-development. Based on the social-psychological literature, we hypothesize that indirect contact predicts future direct contact by reducing intergroup anxiety. Across five longitudinal studies (Study 1: German adults, N = 560; Study 2: German, Dutch, and Swedish school students, N = 6,600; Study 3: Northern Irish children, N = 1,593; Study 4: Northern Irish adults, N = 404; Study 5: German adults, N = 735), we systematically examined this effect, and further tested the mediating role of intergroup anxiety in Studies 3 to 5. Cross-lagged models provided consistent evidence for the positive effect of indirect contact on future direct contact, while a reduction in intergroup anxiety mediates this effect in most models. Results highlight the importance of indirect contact, which has the potential to increase direct contact, and thus promote social cohesion in diverse contexts, over time.PostprintPeer reviewe

Numerically simulated exposure of children and adults to pulsed gradient fields in MRI

PurposeTo determine exposure to gradient switching fields of adults and children in a magnetic resonance imaging (MRI) scanner by evaluating internal electric fields within realistic models of adult male, adult female, and child inside transverse and longitudinal gradient coils, and to compare these results with compliance guidelines. Materials and MethodsPatients inside x-, y-, and z-gradient coils were simulated using anatomically realistic models of adult male, adult female, and child. The induced electric fields were computed for 1 kHz sinusoidal current with a magnitude of 1 A in the gradient coils. Rheobase electric fields were then calculated and compared to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) 2004 and International Electrotechnical Commission (IEC) 2010 guidelines. The effect of the human body, coil type, and skin conductivity on the induced electric field was also investigated. ResultsThe internal electric fields are within the first level controlled operating mode of the guidelines and range from 2.7V m(-1) to 4.5V m(-1), except for the adult male inside the y-gradient coil (induced field reaches 5.4V m(-1)).The induced electric field is sensitive to the coil type (electric field in the skin of adult male: 4V m(-1), 4.6V m(-1), and 3.8V m(-1) for x-, y-, and z-gradient coils, respectively), the human body model (electric field in the skin inside y-gradient coil: 4.6V m(-1), 4.2V m(-1), and 3V m(-1) for adult male, adult female, and child, respectively), and the skin conductivity (electric field 2.35-4.29% higher for 0.1S m(-1) skin conductivity compared to 0.2S m(-1)). ConclusionThe y-gradient coil induced the largest fields in the patients. The highest levels of internal electric fields occurred for the adult male model. J. Magn. Reson. Imaging 2016;44:1360-1367

Relativistic Mean-Field Theory and the High-Density Nuclear Equation of State

The properties of high-density nuclear and neutron matter are studied using a relativistic mean-field approximation to the nuclear matter energy functional. Based on ideas of effective field theory, nonlinear interactions between the fields are introduced to parametrize the density dependence of the energy functional. Various types of nonlinearities involving scalar-isoscalar ($\sigma$), vector-isoscalar ($\omega$), and vector-isovector ($\rho$) fields are studied. After calibrating the model parameters at equilibrium nuclear matter density, the model and parameter dependence of the resulting equation of state is examined in the neutron-rich and high-density regime. It is possible to build different models that reproduce the same observed properties at normal nuclear densities, but which yield maximum neutron star masses that differ by more than one solar mass. Implications for the existence of kaon condensates or quark cores in neutron stars are discussed.Comment: 26 pages in RevTex, 12 PostScript figure

Intergroup contact and social change: Implications of negative and positive contact for collective action in advantaged and disadvantaged groups

Previous research has shown that (1) positive intergroup contact with an advantaged group can discourage collective action among disadvantaged-group members and (2) positive intergroup contact can encourage advantaged-group members to take action on behalf of disadvantaged outgroups. Two studies investigated the effects of negative as well as positive intergroup contact. Study 1 (N = 482) found that negative but not positive contact with heterosexual people was associated with sexual-minority students’ engagement in collective action (via group identification and perceived discrimination). Among heterosexual students, positive and negative contact were associated with, respectively, more and less LGB activism. Study 2 (N = 1,469) found that only negative contact (via perceived discrimination) predicted LGBT students’ collective action intentions longitudinally while only positive contact predicted heterosexual/cisgender students’ LGBT activism. Implications for the relationship between intergroup contact, collective action, and social change are discussed

Dynamics of Hot Bulk QCD Matter: from the Quark-Gluon Plasma to Hadronic Freeze-Out

We introduce a combined macroscopic/microscopic transport approach employing relativistic hydrodynamics for the early, dense, deconfined stage of the reaction and a microscopic non-equilibrium model for the later hadronic stage where the equilibrium assumptions are not valid anymore. Within this approach we study the dynamics of hot, bulk QCD matter, which is expected to be created in ultra-relativistic heavy ion collisions at the SPS, the RHIC and the LHC. Our approach is capable of self-consistently calculating the freeze-out of the hadronic system, while accounting for the collective flow on the hadronization hypersurface generated by the QGP expansion. In particular, we perform a detailed analysis of the reaction dynamics, hadronic freeze-out, and transverse flow.Comment: 55 pages, 15 figure

Social Class

Discussion of class structure in fifth-century Athens, historical constitution of theater audiences, and the changes in the comic representation of class antagonism from Aristophanes to Menander

Neighbourhood identity helps residents cope with residential diversification: contact in increasingly mixed neighbourhoods of Northern Ireland

Research on residential diversification has mainly focused on its negative impacts upon community cohesion and positive effects on intergroup relations. However, these analyses ignore how neighbourhood identity can shape the consequences of diversification among residents. Elsewhere, research using the Applied Social Identity Approach (ASIA) has demonstrated the potential for neighbourhood identity to provide social and psychological resources to cope with challenges. The current paper proposes a novel model whereby these ‘Social Cure’ processes can enable residents to cope with the specific challenges of diversification. We present two studies in support of this model, each from the increasingly religiously desegregated society of post-conflict Northern Ireland. Analysis of the 2012 ‘Northern Ireland Life and Times’ survey shows that across Northern Ireland, neighbourhood identity impacts positively upon both wellbeing and intergroup attitudes via a reduction in intergroup anxiety. A second custom-designed survey of residents in a newly-mixed area of Belfast shows that neighbourhood identification predicts increased wellbeing, reduced intergroup anxiety and reduced prejudice, independently of group norms and experiences of contact. For political psychologists, our evidence suggests a reformulation of the fundamental question of ‘what effects does residential mixing have on neighbourhoods?’ to ‘how can neighbourhood communities support residents to collectively cope with contact?’