Optimal stability and instability for near-linear Hamiltonians

In this paper, we will prove a very general result of stability for perturbations of linear integrable Hamiltonian systems, and we will construct an example of instability showing that both our result and our example are optimal. Moreover, in the same spirit as the notion of KAM stable integrable Hamiltonians, we will introduce a notion of effectively stable integrable Hamiltonians, conjecture a characterization of these Hamiltonians and show that our result prove this conjecture in the linear case

International Respiratory Infections Society COVID Research Conversations: Podcast 2 with Dr. Michael S. Niederman and Dr. Edward J. Schenck

Section(s) Topics 1–4 Introductions 5 COVID-19 in New York City 6–7 Telemedicine, long-term sequelae 8 Development of a multi-disciplinary ICU team 9–10 Treatment of ARDS, COVID-19 pathogenesis 11–12 Prioritizing treatment at research 13 Challenges in tracing the natural history of severe COVID-19 14–15 Experience with mechanically ventilated patients; non-pulmonary organ failure 16–17 Mapping COVID-19 trajectories by SOFA score 18–20 Findings: additive organ dysfunction, improving vs. worsening trajectory 21 ARDS therapeutic approaches 22 Clinical trials involving Cornell 23–25 Lessons learned: patient care, research, education, caring for critical care workers 26–30 2021 predictions: improved therapies and research, endemic COVID-19, vaccines 31–33 Prioritizing research projects at Cornell 34–38 Explanations for caseload reduction 39–43 Thanks and sign-of

Stability transitions for axisymmetric relative equilibria of Euclidean symmetric Hamiltonian systems

In the presence of noncompact symmetry, the stability of relative equilibria under momentum-preserving perturbations does not generally imply robust stability under momentum-changing perturbations. For axisymmetric relative equilibria of Hamiltonian systems with Euclidean symmetry, we investigate different mechanisms of stability: stability by energy-momentum confinement, KAM, and Nekhoroshev stability, and we explain the transitions between these. We apply our results to the Kirchhoff model for the motion of an axisymmetric underwater vehicle, and we numerically study dissipation induced instability of KAM stable relative equilibria for this system.Comment: Minor revisions. Typographical errors correcte

Revisiting Global Information Systems Management Education

Business enterprises continue to globalize, motivated by their search for new markets, greater efficiency in the use of resources, and greater competitiveness. Information systems and technologies serve as one of the critical success factors for making this possible. Some IS curricula supported this development by either integrating more globalization into current courses or by delivering stand-alone courses in Global IS Management as electives or requirements. The purpose of this paper is to review and propose best practices for the Global IS Management course, and consider contingencies that can be expected to influence the choice and success of various approaches. The paper provides a categorization of such courses based on differences in education level (graduate/undergraduate) and student population (MIS/InternationalBusiness/ mixed). We discuss experiences with approaches and practices that work across these segments, and activities targeted to each segment. The paper revisits and argues for the need to expand this curriculum, and provides practical details for MIS faculty who seek to integrate it into their own programs