We revisit the question of when can dispersal-induced coupling between discrete sink populations cause overall population growth? Such a phenomenon is called dispersal driven growth and provides a simple explanation of how dispersal can allow populations to persist across discrete, spatially heterogeneous, environments even when individual patches are adverse or unfavourable. For two classes of mathematical models, one linear and one non-linear, we provide necessary conditions for dispersal driven growth in terms of the non-existence of a common linear Lyapunov function, which we describe. Our approach draws heavily upon the underlying positive dynamical systems structure. Our results apply to both discrete- and continuous-time models. The theory is illustrated with examples and both biological and mathematical conclusions are drawn.
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http://dx.doi.org/10.1016/j.jtbi.2017.03.030 | DOI Listing |
ACS Omega
January 2025
Department of Chemistry, School of Natural Sciences, National University of Sciences and Technology, H-12, Islamabad 44000, Pakistan.
Implementing a hydrogen economy on an industrial scale poses challenges, particularly in developing cost-effective and stable catalysts for water electrolysis. This study explores the catalytic potential of selenium nanoparticles (Se-NPs) synthesized via a simple chemical bath deposition method for electrochemical and photoelectrochemical (PEC) water splitting. The successful fabrication of Se-NPs on fluorine-doped tin oxide (FTO) electrodes has been confirmed using a wide range of analytical tools like X-ray diffraction, energy-dispersive X-ray spectroscopy, and scanning electron microscopy.
View Article and Find Full Text PDFEcol Lett
January 2025
State Key Laboratory of Plant Diversity and Specialty Crops, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China.
Biotic interactions play an important role in species diversification and maintenance and, thus, are regarded as the architecture of biodiversity. Since Darwin and Wallace, biologists have debated whether biotic interactions are stronger towards the tropics and on continents, when compared to temperate regions and islands. Here, based on 354 avian frugivory networks accounting for 22,199 interactions between 1247 bird species and 2126 plant species, we quantified trait matching strength, which reflects interaction strength and specificity, across gradients of latitude and insularity globally.
View Article and Find Full Text PDFSoft Matter
January 2025
Soft Condensed Matter Group, Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bangalore 560 080, India.
The adsorption of charged clay nanoplatelets plays an important role in stabilizing emulsions by forming a barrier around the emulsion droplets and preventing coalescence. In this work, the adsorption of charged clay nanoplatelets on a preformed Latex microsphere in an aqueous medium is investigated at high temporal resolution using optical tweezer-based single-colloid electrophoresis. Above a critical clay concentration, charged clay nanoplatelets in an aqueous medium self-assemble gradually to form gel-like networks that become denser with increasing medium salinity.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States.
Stacking interactions are a recurring motif in supramolecular chemistry and biochemistry, where a persistent theme is a preference for parallel-displaced aromatic rings rather than face-to-face π-stacking. This is typically explained in terms of quadrupole-quadrupole interactions between the arene moieties but that interpretation is inconsistent with accurate calculations, which reveal that the quadrupolar picture is qualitatively wrong. At typical π-stacking distances, quadrupolar electrostatics may differ in sign from an exact calculation based on charge densities of the interacting arenes.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China.
In traditional atom transfer radical polymerization (ATRP), oxygen must be meticulously eliminated due to its propensity to quench radical species and halt the polymerization process. Additionally, oxygen oxidizes the lower-valent Cu catalyst, compromising its ability to activate alkyl halides and propagate polymerization. In this study, we present an oxygen-driven ATRP utilizing alkylborane compounds, a method that not only circumvents the need for stringent oxygen removal but also exploits oxygen as an essential cofactor to promote polymerization.
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