Brueckner Theory of Nuclear Matter with Nonnucleonic Degrees of Freedom and Relativity

For the past 40 years, Brueckner theory has proven to be a most powerful tool to investigate systematically models for nuclear matter. I will give an overview of the work done on nuclear matter theory, starting with the simplest model and proceeding step by step to more sophisticated models by extending the degrees of freedom and including relativity. The final results of a comprehensive hadronic theory of nuclear matter are compared to the predictions by currently fashionable two-nucleon force models. It turns out that a two-nucleon force can, indeed, reproduce those results if the potential is nonlocal, since nonlocality is an inherent quality of the more fundamental fieldtheoretic approach. This nonlocality is crucial for creating sufficient nuclear binding.Comment: Latex (WS style), 16 pages, 7 figures; invited talk presented at the Tenth International Conference on Recent Progress in Many-Body Theories, September 10-15, 1999, Seattle, Washington, USA; to be published in Advances in Quantum Many-Body Theory, Vol. 3 (World Scientific, Singapore); dedicated to Keith Brueckner on the occasion of his 75th birthda

On the Duality of Probing and Fault Attacks

In this work we investigate the problem of simultaneous privacy and integrity protection in cryptographic circuits. We consider a white-box scenario with a powerful, yet limited attacker. A concise metric for the level of probing and fault security is introduced, which is directly related to the capabilities of a realistic attacker. In order to investigate the interrelation of probing and fault security we introduce a common mathematical framework based on the formalism of information and coding theory. The framework unifies the known linear masking schemes. We proof a central theorem about the properties of linear codes which leads to optimal secret sharing schemes. These schemes provide the lower bound for the number of masks needed to counteract an attacker with a given strength. The new formalism reveals an intriguing duality principle between the problems of probing and fault security, and provides a unified view on privacy and integrity protection using error detecting codes. Finally, we introduce a new class of linear tamper-resistant codes. These are eligible to preserve security against an attacker mounting simultaneous probing and fault attacks

Gammel, Betty

Gammel is a store owner in Ecru, MS

Broken-Symmetry Ground States of Halogen-Bridged Binuclear Metal Complexes

Based on a symmetry argument, we study ground states of what we call MMX-chain compounds, which are the new class of halogen-bridged metal complexes. Commensurate density-wave solutions of a relevant multi-band Peierls-Hubbard model are systematically revealed within the Hartree-Fock approximation. We numerically draw ground-state phase diagrams, where various novel density-wave states appear.Comment: 5 pages, 4 figures embedded, to appear in Phys. Lett.

Lacing Up the Gloves: Women, Boxing and Modernity

This article explores women's early twentieth-century engagement with boxing as a means of expressing the fragmentations and contradictions of modern life. Equally drawn to and repelled by the visceral agonism of the sport, female artists and writers of the First World War and post-war era appropriated the boxer's virile body in written and visual autobiographies, effectively breaching male territory and anticipating contemporary notions of female autonomy and self-realization. Whether by reversing the gaze of desire as a ringside spectator or inhabiting the physical sublime of boxing itself, artists such as Djuna Barnes, Vicki Baum, Mina Loy and Clara Bow enlisted the tropes, metaphors and physicality of boxing to fashion a new understanding of their evolving status and identity within a changing social milieu. At the same time, their corporeal and textual self-inscriptions were used to stage their own exclusion from the sport and the realm of male agency and power. Ultimately, while modernist women employ boxing to signal a radical break with the past, or a reinvention of self, they also use it to stage the violence and trauma of the era, aware of limits and vulnerabilities

Leading followers and teams in innovation processes

Leaders must support their followers’ and teams’ innovation to maintain the competitive advantage of their organisation. Rosing, Frese, and Bausch (2011) proposed that leaders can facilitate follower and team innovation through Ambidextrous Leadership (AL), which consists of the following subcomponents: Opening Leader Behaviour (OLB) for the support of idea generation, Closing Leader Behaviour (CLB) for the support of idea implementation, and temporal flexibility, that is, the leader’s ability to flexibly switch between OLB and CLB as situationally required in innovation processes. This thesis aims to contribute to the study of AL by further validating the concept and showing if and how exactly AL relates to different measures of follower and team innovation. In particular, the thesis addresses the following research needs that arise from the AL literature. First, existing studies have measured AL as the combination of OLB and CLB but have not yet specified nor measured temporal flexibility. Second, AL must yet prove that it is distinguishable from existing leadership constructs and that it predicts innovation outcomes beyond these. Third, although innovation work is often carried out by teams, evidence for the positive relationship of AL with team innovation is insufficient and mediators, which explain this relationship, remain unclear. This thesis consists of four empirical studies that address these shortcomings. In Study 1, I explored manifestations of temporal flexibility in the form of the observable Temporal Flexibility Behaviour (TFB) using data from qualitative interviews. The interviews revealed manifestations of TFB through which leaders orchestrate and stimulate followers’ switching between idea generation and implementation. In Study 2, I used these findings and cross sectional data from employees to develop a reliable 6-item TFB scale, which I then combined with existing scales for OLB and CLB to introduce a conceptually complete AL measure for questionnaire based research. In Study 3, I used new cross-sectional data from employees to investigate the convergent, discriminant, and incremental validity of AL in relation to established leadership constructs and to test whether adding TFB to OLB and CLB increased the predictive power of the AL measure with regard to follower innovation outcomes. Results indicated that AL, measured with and without TFB, has convergent and discriminant validity in relation to transformational leadership, contingent rewards, Leader-Member-Exchange, consideration, and initiating structure. The incomplete measure of AL (combination of OLB and CLB) predicted follower innovation outcomes beyond the established leadership constructs. However, adding TFB to OLB and CLB did not consistently increase the predictive power of AL. In Study 4, I used cross sectional data from work teams to test if AL also positively relates to team innovation and whether adding TFB to OLB and CLB increases the predictive power of the AL measure for team innovation. I found that AL was positively related to team innovation (as rated by team members) and that adding TFB increased the predictive power of the AL measure, which shows the relevance of TFB. Team Climate for Innovation (perceived support for innovation in particular) mediated the relationship. In sum, the thesis provides an extension of existing AL measures and new evidence for the validity of AL in its proposed domain of application, that is, follower and team innovation.Führungskräfte müssen die Innovationskraft ihrer Mitarbeiter und Teams fördern, um ihrer Organisation einen langfristigen Wettbewerbsvorteil zu verschaffen. Rosing, Frese und Bausch (2011) schlugen vor, dass Mitarbeiter und Teaminnovation durch Ambidextrous Leadership (AL) gefördert werden können. AL besteht aus den Führungsverhaltensweisen (1) Opening Leader Behaviour (OLB), welches Ideengenerierung fördert, (2) Closing Leader Behaviour (CLB), welches die Umsetzung von Ideen fördert und (3) Temporal Flexibility – der Fähigkeit, zwischen OLB und CLB flexibel zu wechseln, so wie es der Innovationsprozess erfordert. Diese Doktorarbeit möchte dazu beitragen, das Konzept von AL weiter zu validieren und zu zeigen, ob und wie genau AL mit Mitarbeiter- und Teaminnovation zusammenhängt. Dabei adressiert die Arbeit folgende Forschungslücken, die sich aus der bestehenden Literatur ergeben: Erstens haben Studien zwar Skalen für OLB und CLB zur Messung von AL kombiniert, jedoch nicht die dritte Teilkomponente Temporal Flexibility spezifiziert oder gemessen. Zweitens wurde noch nicht umfassend gezeigt, inwiefern AL von existierenden Führungskonstrukten unterscheidbar ist und über diese hinaus Innovation vorhersagt. Drittens gibt es in der bisherigen Forschung kaum Befunde über den positiven Zusammenhang von AL und Teaminnovation sowie über dahinter liegende Mechanismen, obwohl Innovationsarbeit meist in Teams geschieht. Diese Arbeit besteht aus vier empirischen Studien, die diese Forschungslücken behandeln. In Studie 1 wurde mithilfe von qualitativen Interviews konkretes Führungsverhalten exploriert, in welchem sich Temporal Flexibility manifestiert (Temporal Flexibility Behaviour, TFB). Darauf aufbauend wurde in Studie 2 eine TFB Skala mithilfe von Querschnittsdaten von Angestellten entwickelt und mit existierenden Skalen für OLB und CLB kombiniert, um ein vollständiges Messinstrument für AL zu bilden. In Studie 3 wurde anschließend und auf Basis neuer Querschnittsdaten von Angestellten untersucht, ob AL von etablierten Führungskonstrukten unterscheidbar ist und inkrementelle Validität in Bezug auf Mitarbeiterinnovation besitzt. Zu zeigen galt dabei ebenso, ob das Hinzufügen von TFB zu OLB und CLB die Vorhersagekraft des AL Messinstruments erhöht. Studie 4 testete dann mithilfe von Querschnittsdaten aus Arbeitsteams, ob AL ebenso mit Teaminnovation positiv zusammenhängt und die Hinzunahme von TFB die Vorhersagekraft des Messinstruments wiederum erhöht. Darüber hinaus testete die Studie, ob ein Teamklima für Innovation (West, 1990) den Zusammenhang zwischen AL und Teaminnovation mediiert. Die Ergebnisse von Studie 1 zeigten, dass TFB in Form von spezifischen Verhaltensweisen beobachtbar ist, mit welchen Führungskräfte das Wechseln zwischen Phasen der Ideengenerierung und umsetzung orchestrieren und stimulieren. Studie 2 resultierte in einer reliablen 6 Item Skala für TFB. Studie 3 zeigte dann, dass AL (gemessen mit und ohne TFB) in Relation zu den Führungskonstrukten transformationale Führung, Contingent Rewards, Leader-Member-Exchange, Consideration, und Initiating Structure konvergente und diskriminante Validität besitzt. Die Kombination von OLB und CLB als Maß für AL sagte Mitarbeiterinnovation über diese Konstrukte hinaus vorher. Die Hinzunahme von TFB zu OLB und CLB führte jedoch nicht in allen Analysen zu einem Zugewinn an Vorhersagekraft. Die Ergebnisse von Studie 4 zeigten hingegen, dass AL positiv mit Teaminnovation (eingeschätzt durch die Teammitglieder) zusammenhängt und dabei die Hinzunahme von TFB zu OLB und CLB die Vorhersagekraft des AL-Messinstruments erhöhte, was die Bedeutung von TFB betont. Darüber hinaus vermittelte das Teamklima für Innovation – insbesondere die wahrgenommene Unterstützung für Innovation – den positiven Zusammenhang zwischen AL und Teaminnovation. Diese Doktorarbeit ermöglicht damit eine Erweiterung der Messung von AL und liefert neue Evidenz für die Relevanz und Wirkmechanismen von AL im Innovationskontext