Exploring Vertex Interactions in Ferroelectric Flux-Closure Domains

Using piezoresponse force microscopy, we have observed the progressive development of ferroelectric flux-closure domain structures and Landau−Kittel-type domain patterns, in 300 nm thick single-crystal BaTiO3 platelets. As the microstructural development proceeds, the rate of change of the domain configuration is seen to decrease exponentially. Nevertheless, domain wall velocities throughout are commensurate with creep processes in oxide ferroelectrics. Progressive screening of macroscopic destabilizing fields, primarily the surface-related depolarizing field, successfully describes the main features of the observed kinetics. Changes in the separation of domain-wall vertex junctions prompt a consideration that vertex−vertex interactions could be influencing the measured kinetics. However, the expected dynamic signatures associated with direct vertex−vertex interactions are not resolved. If present, our measurements confine the length scale for interaction between vertices to the order of a few hundred nanometers.

Sequential injection of domain walls into ferroelectrics at different bias voltages: Paving the way for “domain wall memristors”

Simple meso-scale capacitor structures have been made by incorporating thin (300 nm) single crystal lamellae of KTiOPO4 (KTP) between two coplanar Pt electrodes. The influence that either patterned protrusions in the electrodes or focused ion beam milled holes in the KTP have on the nucleation of reverse domains during switching was mapped using piezoresponse force microscopy imaging. The objective was to assess whether or not variations in the magnitude of field enhancement at localised “hot-spots,” caused by such patterning, could be used to both control the exact locations and bias voltages at which nucleation events occurred. It was found that both the patterning of electrodes and the milling of various hole geometries into the KTP could allow controlled sequential injection of domain wall pairs at different bias voltages; this capability could have implications for the design and operation of domain wall electronic devices, such as memristors, in the future.

Advances in GPCR modeling evaluated by the GPCR Dock 2013 assessment:Meeting new challenges

Despite tremendous successes of GPCR crystallography, the receptors with available structures represent only a small fraction of human GPCRs. An important role of the modeling community is to maximize structural insights for the remaining receptors and complexes. The community-wide GPCR Dock assessment was established to stimulate and monitor the progress in molecular modeling and ligand docking for GPCRs. The four targets in the present third assessment round presented new and diverse challenges for modelers, including prediction of allosteric ligand interaction and activation states in 5-hydroxytryptamine receptors 1B and 2B, and modeling by extremely distant homology for smoothened receptor. Forty-four modeling groups participated in the assessment. State-of-the-art modeling approaches achieved close-to-experimental accuracy for small rigid orthosteric ligands and models built by close homology, and they correctly predicted protein fold for distant homology targets. Predictions of long loops and GPCR activation states remain unsolved problems.

Status of GPCR modeling and docking as reflected by community-wide GPCR Dock 2010 assessment

The community-wide GPCR Dock assessment is conducted to evaluate the status of molecular modeling and ligand docking for human G protein-coupled receptors. The present round of the assessment was based on the recent structures of dopamine D3 and CXCR4 chemokine receptors bound to small molecule antagonists and CXCR4 with a synthetic cyclopeptide. Thirty-five groups submitted their receptor-ligand complex structure predictions prior to the release of the crystallographic coordinates. With closely related homology modeling templates, as for dopamine D3 receptor, and with incorporation of biochemical and QSAR data, modern computational techniques predicted complex details with accuracy approaching experimental. In contrast, CXCR4 complexes that had less-characterized interactions and only distant homology to the known GPCR structures still remained very challenging. The assessment results provide guidance for modeling and crystallographic communities in method development and target selection for further expansion of the structural coverage of the GPCR universe.

The continued salience of religious voting in the United States, Germany, and Great Britain

Conventional wisdom on party systems in advanced industrial democracies holds that modern electorates are dealigned and that social cleavages no longer structure party politics. Recent work on class cleavages has challenged this stylized fact. The analysis performed here extends this criticism to the religious-secular cleavage. Using path analysis and comparing the current electorates of the United States, Germany, and Great Britain with the early 1960s, this paper demonstrates that the religious-secular cleavage remains or has become a significant predictor of conservative vote choice. While the effects of the religious-secular cleavage on vote choice have become largely indirect, the total of the direct and indirect effects is substantial and equivalent to the effects of class and status.

The politicization of indigenous identities in Peru

Until now, scholars have argued that, unlike other Latin American countries with sizable indigenous populations, indigenous politics are largely unimportant in Peru because indigenous-based parties or national-level movements are absent. Rather than focusing solely on the emergence of indigenous parties or movements, which ignores the larger consequence of individuals' indigenous identifications for electoral politics, we argue that it is more important to examine the emergence of indigenous political divisions and their effects on indigenous representation. Using data from the World Values Survey across the presidential elections of 1995, 2001, and 2006, we show that, as indigenous identity has become more carefully defined, indigenous voting divisions have emerged in Peru, and concomitantly, parties have begun to recognize and respond to these divisions.

Increasingly ‘Irrational’ Party Systems: Evidence that There Are Increasingly More Than Two at the District level

Recent work has noted an increase in the number of parties at the national level in both proportional and majoritarian electoral systems. While the conventional wisdom maintains that the incentives provided by the electoral system will prevent the number of parties at the district level from exceeding two in majoritarian systems, the evidence presented here demonstrates otherwise. I argue that this has occurred because the number of cleavages articulated by parties has increased as several third parties have begun articulating cleavages that are not well represented by the two larger parties.

Due North? Do American Theories of Legislative Committees Apply to Canada?

Several theories of legislative organisation have been proposed to explain committee selection in American legislatures, but do these theories travel outside the United States? This paper tests whether these theories apply to data from the Canadian House of Commons. It was found that the distributive and partisan models of legislative organisation explain committee composition in Canada. In many cases, committees in the House of Commons are made up of preference outliers. As predicted by partisan models, it was also found that the governing party stacks committees with its members, but this is conditional upon the strength of the governing party.

Parties, cleavages, and issue evolution: The case of the religious-secular cleavage in Chile

Several recent articles have reached different conclusions regarding the impact of the religious–secular cleavage in Chile. The resolution of this debate has important consequences for the understanding of cleavages. Studies subscribing to the view that parties have considerable agency in the maintenance of cleavages have found that religiosity no longer affects vote choice, while studies rooted in a sociological perspective argue that religiosity still matters. We show that the reason for the discrepant results is because a partisan realignment is underway, whereby religious voters are gradually shifting their loyalties from the parties of the left to the parties of the right, matching a division that has taken place at the elite level. These results are consistent with an issue evolution perspective, which provides a clearer articulation of how cleavages form than either the agency or the sociological approaches.

Party agency and the religious-secular cleavage in post-Communist countries: The case of Romania

Research focusing on several post-communist countries has found evidence of social cleavage effects on political behaviour similar to those found in Western Europe. In some post-communist countries, however, social cleavage effects appear far weaker (if at all). To understand why this is the case, I perform a case study of Romania, focusing on the religious–secular cleavage. Drawing upon research that emphasises the role of parties in forming cleavages, I argue that the reason for the absence of social cleavage effects is due to party competition for the same group of voters by parties from opposing ends of the ideological spectrum. By shifting their positions, some parties have prevented the appearance of cleavages by shaping individuals' perceptions of the parties and, in doing so, have even altered individuals' own left–right self-placements.

Civil Society Aid to Post-Communist Countries

A major debate within foreign aid literature is whether civil society can be ‘purchased’ through outside assistance.We test this proposition by exploring the influence of aid provided by the United States Agency for International
Development on post-communist civil rights environments. A review of research critical of international assistance highlights the risk of unsustainability, polarization and dependence among recipient civic organizations.We argue that
a more effective stimulant is socio-economic growth, which stimulates committed constituencies, higher citizen expectations and pressure on the state to protect civil freedoms. Using cross-sectional, time-series data from 27
post-communist countries, we find no evidence that aid independently promotes stronger civil rights environments but that economic growth produces substantial improvements. Further, any aid effectiveness appears to be conditional on economic strength.We conclude that developmental organizations should reassess how and where civil society aid is targeted.

The Effect of the Secret Ballot on Party System Fragmentation: A Test of Three Competing Arguments

Few studies have examined the impact that the adoption of the secret ballot had on party system fragmentation outside the United States. This article tests arguments maintaining that the adoption of the secret ballot had a negative, positive or nil effect on party system fragmentation. Using time-series cross-sectional data from
several countries adopting the secret ballot around the turn of the twentieth century, the results demonstrate that the adoption of the secret ballot did not hinder – though did not favour, either – the development of multiparty systems.

What’s in a (Party) Name?: Examining preferences, discipline, and social identity in a parliamentary free vote

In trying to understand the effects of political parties on shaping the voting behaviour of legislators, research has attempted the difficult task of separating the effects of preferences from rules used by party leaders to enforce discipline. However, little research has explored the prospect that party labels also reflect a social identity that is independent of legislators’ preferences and the rules used by party leaders to enforce discipline. In this study we examine that possibility, employing a data set that permits us to control both for leadership-based effects and legislator preferences on a 2000 free vote dealing with stem cell research. Using the British Representation Studies 1997 – which interviewed Members of Parliament regarding their preferences on several key issues related to the bill – we find significant evidence that party-as-identification plays a role in shaping how legislators vote, even after preferences and discipline are accounted for.