We analyze a discrete-time model of populations that grow and disperse in separate phases. The growth phase is a nonlinear process that allows for the effects of local crowding. The dispersion phase is a linear process that distributes the population throughout its spatial habitat. Our study quantifies the issues of survival and extinction, the existence and stability of nontrivial steady states, and the comparison of various dispersion strategies. Our results show that all of these issues are tied to the global nature of various model parameters. The extreme strategies of staying-in-place and going-everywhere-uniformly are compared numerically to diffusion strategies in various contexts. We approach the mathematical analysis of our model from a functional analysis and an operator theory point of view. We use recent results from the theory of positive operators in Banach lattices.
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J Genet
January 2024
1Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu, Kuala Nerus, Terengganu, Malaysia.
The Brownstripe Snapper, (Quoy and Gaimard, 1824) is a commercially important snapper extensively caught in Malaysia. We examined genetic diversity, population connectivity, and historical demographics of the , off the eastern coast of peninsular Malaysia based on an 817 bp region of the mtDNA control region sequences. Maximum likelihood gene trees demonstrated that the populations under study had limited structuring and formed a single panmictic population that lacks support for internal clades.
View Article and Find Full Text PDFBMC Endocr Disord
December 2024
Basic and Clinical Immunology, Department of Pathology, Faculty of Medicine, University of Porto, Porto, Portugal.
Background: Hashimoto's thyroiditis (HT) is associated with high cardiovascular risk. Thyroid volume has a notable dispersion of values in these patients. This study aims to clarify the association between thyroid antibodies, thyroid morphology, insulin resistance, and lipid profile in patients with HT.
View Article and Find Full Text PDFJ Math Biol
December 2024
Institut de Recherche pour le Développement, IRD, UMMISCO, Sorbonne Université, 93143, Bondy, France.
In this work, we study the model of a fish species growing logistically exploited by a fishing fleet in a heterogeneous environment. The environment is made up of a network of fishing patches connected by fish migrations taking place on a fast time scale. We are interested in the maximum economic yield (MEY) which corresponds to the maximum profit made by the fishing fleet.
View Article and Find Full Text PDFSci Rep
December 2024
Clermont Auvergne University, CNRS, IRD, OPGC, Magmas and Volcanoes Laboratory, 63000, Clermont-Ferrand, France.
The new submarine volcano Fani Maoré offshore Mayotte (Comoros archipelago) discovered in 2019 has raised the awareness of a possible future eruption in Petite-Terre island, located on the same 60 km-long volcanic chain. In this context of a renewal of the volcanic activity, we present here the first volcanic hazard assessment in Mayotte, focusing on the potential reactivation of the Petite-Terre eruptive centers. Using the 2-D tephra dispersal model HAZMAP and the 1979 - 2021 meteorological ERA-5 database, we first identify single eruptive scenarios of various impacts for the population of Mayotte.
View Article and Find Full Text PDFData Brief
December 2024
Instituto de Ciencias de la Atmósfera y Cambio Climático, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico.
Tropical cyclones (TCs) are catastrophic phenomena that constantly threaten populations settled in the tropics. Their direct effects (strong winds, storm surges, and intense precipitation) are confined near the TC center. On the other hand, the indirect effects are due to extreme rainfall events associated with rainbands distant from the TC center.
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