Recent methodological advances provide a rigorous framework to de

Recent methodological advances provide a rigorous framework to determine the relative contribution of different biogeographic processes (e.g., vicariance,

land migration, long-distance dispersal) to the origin of island endemics. With its complex but well-known history of microplate movements and climatic oscillations, the Mediterranean region (including the Mediterranean basin and Macaronesia) provides the geographic backdrop selleck inhibitor for the diversification of Ruta L., the type genus of Rutaceae (citrus family). Phylogenetic, molecular dating, and ancestral range reconstruction analyses were carried out to investigate the extent to which past geological connections and climatic history of the Mediterranean region explain the current distribution of species in Ruta, with emphasis on its island endemics. The analyses showed that Ruta invaded the region from the north well before the onset of the Mediterranean climate and diversified in situ as the climate became Mediterranean. The continental fragment island endemics of the genus originated via processes of land migration/vicariance driven by connections/disconnections between microplates, whereas

the oceanic island endemics were the product of a single colonization event from the mainland followed by in situ diversification. This study emphasizes the need for an integrative, hypothesis-based approach to historical biogeography and stresses the importance of temporary land connections and colonization Selleck GDC 973 opportunity in the biotic assembly of continental fragment and

oceanic islands, respectively.”
“We show that Dirac points can emerge in photonic crystals possessing selleck kinase inhibitor mirror symmetry when band gap closes. The mechanism of generating Dirac points is discussed in a two-dimensional photonic square lattice, in which four Dirac points split out naturally after the touching of two bands with different parity. The emergence of such nodal points, characterized by vortex structure in momentum space, is attributed to the unavoidable band crossing protected by mirror symmetry. The Dirac nodes can be unbuckled through breaking the mirror symmetry and a photonic analog of Chern insulator can be achieved through time reversal symmetry breaking. Breaking time reversal symmetry can lead to unidirectional helical edge states and breaking mirror symmetry can reduce the band gap to amplify the finite size effect, providing ways to engineer helical edge states.”
“We discover Mn-VI-nanoparticles (NPs) bearing functional groups, high oxidation state, strong electron affinity, unique redox and paramagnetic nature, which opens up a new avenue to catalysis, magnetism and material application. However, its synthesis is challenging and remains unexplored because of associated serious difficulties. A simple benign synthetic strategy is devised to fabricate the high-valent NPs using mild reducing agent bromide, which transformed Mn-VII to valuable Mn-VI-species.

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