We show that the onset of global chaos in a time periodically perturbed Hamiltonian system may occur at unusually small magnitudes of perturbation if the unperturbed system possesses more than one separatrix. The relevant scenario is the combination of the overlap in the phase space between resonances of the same order and their overlap in energy with chaotic layers associated with separatrices of the unperturbed system. We develop the asymptotic theory and verify it in simulations.
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http://dx.doi.org/10.1103/PhysRevLett.90.174101 | DOI Listing |
Environ Manage
January 2025
TECNALIA Research & Innovation, Basque Research and Technology Alliance (BRTA), Energy, climate, and urban transition, Parque Tecnológico de Bizkaia, Derio, Spain.
The extent and timescale of climate change impacts remain uncertain, including global temperature increase, sea level rise, and more frequent and intense extreme events. Uncertainties are compounded by cascading effects. Nevertheless, decision-makers must take action.
View Article and Find Full Text PDFJ Electrocardiol
January 2025
Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan. Electronic address:
Purpose Of Review: WHO defines SCD as sudden unexpected death either within 1 h of symptom onset (witnessed) or within 24 h of having been observed alive and symptom-free (unwitnessed). Sudden cardiac arrest is a major cause of mortality worldwide, with survival to hospital discharge for hospital cardiac arrest and in-hospital cardiac arrest being only 9.3 % and 21.
View Article and Find Full Text PDFJ Gerontol B Psychol Sci Soc Sci
January 2025
Helsinki Institute for Demography and Population Health, Faculty of Social Sciences, University of Helsinki, Helsinki, Finland.
Objectives: Cardiovascular disease (CVD) is the leading cause of mortality globally. Examining trends in CVD burden and associated sociodemographic disparities can contribute to tailoring policies that promote cardiovascular health and narrow health disparities. However, existing studies predominantly focus only on mortality.
View Article and Find Full Text PDFViruses
December 2024
Laboratory of Microbiology and Biochemistry (LR16SP01), Aziza Othmana Hospital, University Tunis El Manar, Tunis 1068, Tunisia.
Coronavirus disease 2019 (COVID-19) has been associated with a significant fatality rate and persistent evolution in immunocompromised patients. In this prospective study, we aimed to determine the duration of excretion of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 37 Tunisian patients with hematological malignancies (40.5% with lymphoma and 37.
View Article and Find Full Text PDFViruses
December 2024
University Hospital of UFMA, Federal University of Maranhao, São Luís 65080-805, Maranhão, Brazil.
Chordomas are a low-to-intermediate-grade slow-growing subtype of sarcoma, but show propensity to grow and invade locally with recurrence and metastasis in 10-40% of cases. We describe the first case of spontaneous regression of a solid tumor (histologically and immunohistochemically proven chordoma) after COVID-19. A female patient with clival chordoma underwent occipitocervical fixation prior to tumor resection.
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