The emergence of classical behaviour in magnetic adatoms

A wide class of nanomagnets shows striking quantum behaviour, known as quantum spin tunnelling (QST): instead of two degenerate ground states with opposite magnetizations, a bonding-antibonding pair forms, resulting in a splitting of the ground-state doublet with wave functions linear combination of two classically opposite magnetic states, leading to the quenching of their magnetic moment. Here we study how QST is destroyed and classical behaviour emerges in the case of magnetic adatoms, where, contrary to larger nanomagnets, the QST splitting is in some instances bigger than temperature and broadening. We analyze two different mechanisms for the renormalization of the QST splitting: Heisenberg exchange between different atoms, and Kondo exchange interaction with the substrate electrons. Sufficiently strong spin-substrate and spin-spin coupling renormalize the QST splitting to zero allowing the environmental decoherence to eliminate superpositions between classical states, leading to the emergence of spontaneous magnetization. Importantly, we extract the strength of the Kondo exchange for various experiments on individual adatoms and construct a phase diagram for the classical to quantum transition.

The Society of States under siege? An English School perspective on the emergence of global civil society

In this article I critically examine the theoretical and empirical relationship between world society, whereby global civil society is taken to be its physical or empirical counterpart, and the society of states. This relationship is typically portrayed as contradictory or confrontational, and I contend that this mainstream perspective is reliant on a superficial analysis of the relationship. If one examines the deeper dynamics, viewed in their contemporary international normative context, then one can identify the more constructive and permissive aspects of the relationship. Rather than being wholly incompatible I argue that world society and international society are mutually constitutive and mutually dependent regimes, whose relationship is more often marked by cooperation than by conflict. English School theory provides the conceptual framework for this analysis. The relationship between international and world society presents a core ontological tension within this theory, and again they tend to occupy polarised positions. A synthesis of four international theories - pluralist international society theory, solidarist international society theory, critical international theory, and the discourse of global civil society - informs the hypothesis that the relationship can be normatively and empirically reconciled. In order to empirically support this explanation I analyse two phenomena in world politics - transnational advocacy networks and humanitarian intervention - where there is an apparent tension between international and world society.

Management of vomplex systems: Modeling the biological pest control

The aim of this paper is to study the cropping system as complex one, applying methods from theory of dynamic systems and from the control theory to the mathematical modeling of the biological pest control. The complex system can be described by different mathematical models. Based on three models of the pest control, the various scenarios have been simulated in order to obtain the pest control strategy only through natural enemies' introduction. © 2008 World Scientific Publishing Company.

Emergence of secretion-defective sublines of Pseudomonas aeruginosa PAO1 resulting from spontaneous mutations in the vfr global regulatory gene.

Pseudomonas aeruginosa undergoes spontaneous mutation that impairs secretion of several extracellular enzymes during extended cultivation in vitro in rich media, as well as during long-term colonization of the cystic fibrosis lung. A frequent type of strong secretion deficiency is caused by inactivation of the quorum-sensing regulatory gene lasR. Here we analyzed a spontaneously emerging subline of strain PAO1 that exhibited moderate secretion deficiency and partial loss of quorum-sensing control. Using generalized transduction, we mapped the secretion defect to the vfr gene, which is known to control positively the expression of the lasR gene and type II secretion of several proteases. We confirmed this secretion defect by sequencing and complementation of the vfr mutation. In a reconstruction experiment conducted with a 1:1 mixture of wild-type strain PAO1 and a vfr mutant of PAO1, we observed that the vfr mutant had a selective advantage over the wild type after growth in static culture for 4 days. Under these conditions, spontaneous vfr emerged in a strain PAO1 population after four growth cycles, and these mutants accounted for more than 40% of the population after seven cycles. These results suggest that partial or complete loss of quorum sensing and secretion can be beneficial to P. aeruginosa under certain environmental conditions.

Emergence of normative beliefs legitimizing antisocial behaviour in adolescents : the roles of monitoring, attachment, and temperament /

Beliefs about the rightness or wrongness of engaging in various antisocial acts, referred to here as nonnative beliefs legitimizing antisocial behaviour (nblab), have been shown to playa role in the emergence oflater antisocial behaviour. The current study represented an attempt to understand whether parental monitoring and parent-child attachment have differential relationships with these antisocial nonnative beliefs in adolescents of different temperaments. The participants, 7135 adolescents in 25 high schools (ages 10- 18 years, M = 15.7) completed a wide-ranging questionnaire as part of the broad Youth Lifestyle Choices - Community University Research Alliance project, whose goal is to identify and describe the major developmental pathways of risk behaviours and resilience in youth. Two aspects of monitoring (monitoring knowledge and surveillance/tracking), attachment security, and two measures of temperament (activity level and approach) were examined for main effects and in interactions as predictors of adolescent nonnative beliefs. All of these measures were based on adolescent self-ratings on either 3- or 4-point Likert-type scales. Several important results emerged from the study. Males were higher than females in nblab; parental monitoring knowledge and adolescent attachment security were negatively related to nblab; and temperamental activity level was positively related. Monitoring knowledge, the strongest of the predictors, was much more strongly related to nonnative beliefs than was parental surveillance/tracking, supporting the contention that it is how much parents actually know, and not their surveillance efforts, that predict adolescent nonnative beliefs. A surprising finding that is of the utmost importance was that, although several of the interactions tested were significant, none were considered to be of a meaningful magnitude (defined as sr^ > .01). The current study supported the suggestion that normative beliefs legitimizing antisocial behaviour are multiply determined, and the results were discussed with respect to the observed differential relations of parental monitoring, parent-child attachment, temperament, age, and gender to antisocial normative beliefs in adolescents. Also discussed were the need to test other parenting, temperament, and other variables that may be involved in the development of nblab; the need to directly test possible mechanisms explaining the links among the variables; and the usefulness of longitudinal research in determining possible directions of causality and developmental changes in the relationships.

Revisiting the emergence of the modern business enterprise: entrepreneurship and the Singer global distribution system

This paper approaches the question of why entrepreneurial firms exist from a broad business historical perspective. It observes that the original development of the modern business enterprise was very strongly associated with entrepreneurial innovation rather than an extension of managerial routine. The widely-used theory of the entrepreneur as a specialist in judgmental decision making is applied to the particular point in time when entrepreneurs had to develop novel organizational designs in what Chandler described as the prelude to the ‘managerial revolution’. The paper illustrates how the theory of entrepreneurship then best explains the rise of the modern corporation by focusing on the case study of vertical integration par excellence, Singer.

Latin America’s emergence in global services A new driver of structural change in the region?

Includes bibliography.

The Emergence of Partnership Networks in the Enterprise Application Development Industry - A Global Corporation Perspective

Currently, dramatic changes are happening in the IS development industry. The incumbent system developers (hubs) are embracing partnerships with less well established companies (spokes), acting in specific niches. This paper seeks to establish a better understanding of the motives for this strategy. Relying on existing work on strategic alliance formation, it is argued that partnering is particularly attractive, if these small companies possess certain capabilities that are difficult to obtain through other arrangements than partnering. Again drawing on the literature, three categories of capabilities are identified: the capability to innovate within their niche, the capability to provide a specific functionality that can be integrated with the incumbents’ systems, and the capability to address novel markets. These factors are analyzed through a case study. The case represents a market leader in the global IS development industry, which fosters a network of smaller partner firms. The study reveals that temporal dynamics between the identified factors are playing a dominant role in these networks. A cyclical partnership model is developed that attempts to explain the life cycle of a partnership within such a network.