Non-d0d^0 Mn-driven ferroelectricity in antiferromagnetic BaMnO3_3

Using first-principles density functional theory we predict a ferroelectric ground state -- driven by off-centering of the magnetic Mn$^{4+}$ ion -- in perovskite-structure BaMnO$_3$. Our finding is surprising, since the competition between energy-lowering covalent bond formation, and energy-raising Coulombic repulsions usually only favors off-centering on the perovskite $B$-site for non-magnetic $d^0$ ions. We explain this tendency for ferroelectric off-centering by analyzing the changes in electronic structure between the centrosymmetric and polar states, and by calculating the Born effective charges; we find anomalously large values for Mn and O consistent with our calculated polarization of 12.8 $\mu$C/cm$^2$. Finally, we suggest possible routes by which the perovskite phase may be stabilized over the usual hexagonal phase, to enable a practical realization of a single-phase multiferroic.Comment: 6 pages, 3 figure

Who Wants to Return Home? A Survey of Sudanese Refugees in Kakuma, Kenya

With the goal of better understanding some of the psychological factors related to refugees’ desire to return home, surveys were administered to 235 South Sudanese refugees living in the Kakuma Refugee Camp in Kenya. Respondents were asked about how much they wanted to return to Sudan, their emotional reactions about returning, their views on the prospects for peace, their expectations regarding how they would be received upon return, and their concerns about specific challenges they might face. In addition, they completed an inventory measuring their personal beliefs about issues in five domains: vulnerability, injustice, distrust, superiority, and helplessness in regard to prospective returnees to Sudan. A large majority was very eager to repatriate. Individual differences in attitudes toward returning were significantly linked to the strength of their beliefs in the five domains. Stronger beliefs about vulnerability, injustice, distrust, and helplessness were associated with more negative perceptions of return, while a stronger belief about returnee superiority was correlated with a more favourable perspective on repatriation.Dans le but de mieux comprendre quelques-uns des facteurs psychologiques liés au désir des réfugiés de retourner chez eux, des enquêtes ont été conduites auprès de 235 réfugiés originaires du sud Soudan et vivant dans le camp de réfugiés de Kakuma, au Kenya. On posa aux répondants des questions sur l’intensité de leur désir de retourner au Soudan, leurs réactions émotionnelles par rapport à toute la question du retour, leur point de vue sur les perspectives pour la paix, leurs attentes quant à la façon dont ils seraient reçus au retour, et leurs préoccupations quant aux défis spécifiques qui pourraient les confronter. En plus, ils complétèrent aussi un inventaire de personnalité permettant d’évaluer leurs croyances personnelles sur des questions relatives à cinq domaines : la vulnérabilité, l’injustice, la méfiance, la supériorité, et le sentiment d’impuissance par rapport aux éventuels candidats au retour au Soudan. La grande majorité était très désireuse de rentrer au pays. Les différences individuelles dans les attitudes par rapport au retour étaient étroitement liées à l’intensité de leur croyance dans les cinq domaines. Une croyance plus forte dans la vulnérabilité, l’injustice, la méfiance, et le sentiment d’impuissance était associée à des perceptions plutôt négatives sur le retour, alors qu’une croyance plus forte quant à la supériorité du réfugié revenant chez lui était corrélée avec une perspective plus favorable sur le retour

Collective narcissism and its social consequences.

This article introduces the concept of collective narcissism—an emotional investment in an unrealistic belief about the in group's greatness—aiming to explain how feelings about an ingroup shape a tendency to aggress against outgroups. The results of 5 studies indicate that collective, but not individual, narcissism predicts intergroup aggressiveness. Collective narcissism is related to high private and low public collective self-esteem and low implicit group esteem. It predicts perceived threat from outgroups, unwillingness to forgive outgroups, preference for military aggression over and above social dominance orientation, right-wing authoritarianism, and blind patriotism. The relationship between collective narcissism and aggressiveness is mediated by perceived threat from outgroups and perceived insult to the ingroup. In sum, the results indicate that collective narcissism is a form of high but ambivalent group esteem related to sensitivity to threats to the ingroup's image and retaliatory aggression

Patterned Inequality, Compounding Injustice, and Algorithmic Prediction

If whatever counts as merit for some purpose is unevenly distributed, a decision procedure that accurately sorts people on that basis will “pick up” and reproduce the pre-existing pattern in ways that more random, less merit-tracking procedures would not. This dynamic is an important cause for concern about the use of predictive models to allocate goods and opportunities. In this article, I distinguish two different objections that give voice to that concern in different ways. First, decision procedures may contribute to future social injustice and other social ills by sustaining or aggravating patterns that undermine equality of status and opportunity. Second, the same decision procedures may wrong particular individuals by compounding prior injustices that explain those persons’ predicted or actual characteristics. I argue for the importance of the first idea and raise doubts about the second. In normative assessments and legal regulation of algorithmic decisionmaking, as in our thinking about anti-discrimination norms more broadly, a central concern ought to be the prospect of entrenching harmful and unjust patterns—quite apart from any personal wrong done to the individuals about whom predictions are made

Modeling Factions for ‘Effects Based Operations’: Part II – Behavioral Game Theory

Military, diplomatic, and intelligence analysts are increasingly interested in having a valid system of models that span the social sciences and interoperate so that one can determine the effects that may arise from alternative operations (courses of action) in different lands. Part I of this article concentrated on internal validity of the components of such a synthetic framework – a world diplomacy game as well as the agent architecture for modeling leaders and followers in different conflicts. But how valid are such model collections once they are integrated together and used out-of-sample (see Section 1)? Section 2 compares these realistic, descriptive agents to normative rational actor theory and offers equilibria insights for conflict games. Sections 3 and 4 offer two real world cases (Iraq and SE Asia) where the agent models are subjected to validity tests and an EBO experiment is then run for each case. We conclude by arguing that substantial effort on game realism, best-of-breed social science models, and agent validation efforts is essential if analytic experiments are to effectively explore conflicts and alternative ways to influence outcomes. Such efforts are likely to improve behavioral game theory as well

Modeling Factions for \u27Effects Based Operations\u27: Part I Leader and Follower Behaviors

This paper presents a synthetic approach for generating role playing simulation games intended to support analysts (and trainees) interested in testing alternative competing courses of action (operations) and discovering what effects they are likely to precipitate in potential ethno-political conflict situations. Simulated leaders and followers capable of playing these games are implemented in a cognitive modeling framework, called PMFserv, which covers value systems, personality and cultural factors, emotions, relationships, perception, stress/coping style and decision making. Of direct interest, as Sect. 1.1 explains, is mathematical representation and synthesis of best-of-breed behavioral science models within this framework to reduce dimensionality and to improve the realism and internal validity of the agent implementations. Sections 2 and 3 present this for leader profiling instruments and group membership decision-making, respectively. Section 4 serves as an existence proof that the framework has generated several training and analysis tools, and Sect. 5 concludes with lessons learned. Part II turns to the question of assessment of the synthesis and its usage in course of action studies

Impact of the Tax Reform Act of 1986 on corporate real estate asset management

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1987.Bibliography: leaves 76-80.by Bruce A. Eidelson.M.S