Steppes, savannahs, forests and phytodiversity reservoirs during the Pleistocene in the Iberian Peninsula

A palaeobotanical analysis of the Pleistocene floras and vegetation in the Iberian Peninsula shows the existence of patched landscapes with Pinus woodlands, deciduous and mixed forests, parklands (savannah-like), shrublands, steppes and grasslands. Extinctions of Arctotertiary woody taxa are recorded during the Early and Middle Pleistocene, but glacial refugia facilitated the survival of a number of temperate, Mediterranean and Ibero-North African woody angiosperms. The responses of Iberian vegetation to climatic changes during the Pleistocene have been spatially and temporarily complex, including rapid changes of vegetation in parallel to orbital and suborbital variability, and situations of multi-centennial resilience or accommodation to climatic changes. Regional characteristics emerged as soon as for the Middle Pleistocene, if not earlier: Ericaceae in the Atlantic coast indicating wetter climate, thermo-mediterranean elements in the south as currently, and broad-leaf trees in the northeastern. Overall, steppe landscapes and open Pinus woodlands prevailed over many continental regions during the cold spells of the Late Pleistocene. The maintenance of a high phytodiversity during the glacials was linked to several refuge zones in the coastal shelves of the Mediterranean and intramountainous valleys. Northern Iberia, especially on coastal areas, was also patched with populations of tree species, and this is not only documented by palaeobotanical data (pollen, charcoal) but also postulated by phylogeographical models

Coalescent Simulations Reveal Hybridization and Incomplete Lineage Sorting in Mediterranean Linaria

We examined the phylogenetic history of Linaria with special emphasis on the Mediterranean sect. Supinae (44 species). We revealed extensive highly supported incongruence among two nuclear (ITS, AGT1) and two plastid regions (rpl32-trnLUAG, trnS-trnG). Coalescent simulations, a hybrid detection test and species tree inference in *BEAST revealed that incomplete lineage sorting and hybridization may both be responsible for the incongruent pattern observed. Additionally, we present a multilabelled *BEAST species tree as an alternative approach that allows the possibility of observing multiple placements in the species tree for the same taxa. That permitted the incorporation of processes such as hybridization within the tree while not violating the assumptions of the *BEAST model. This methodology is presented as a functional tool to disclose the evolutionary history of species complexes that have experienced both hybridization and incomplete lineage sorting. The drastic climatic events that have occurred in the Mediterranean since the late Miocene, including the Quaternary-type climatic oscillations, may have made both processes highly recurrent in the Mediterranean flora

Adsorption of U(VI) from Aqueous Solution onto Hydrotalcite-Like Compounds

Uranium adsorption by the synthesized compound of magnesium aluminum hydroxide hydrate – layered double hydrotalcite (STH)-like compounds was studied. The calcinated STH was proven to be a highly effective in U(VI) adsorption in pH range from 6.5 to 7. The time dependent experimental data were found to be fit to the pseudo-second-oder model. The equilibrium data have been modeled using Langmuir and Freundlich isotherms. The results showed that both model provide the best correlation with equilibrium data. The highest adsorption capacity, approximated 62.5 mg/g, was observed in the calcinated STH at 500 °C. The positive value of enthalpy change indicated that adsorption reaction of U(VI) on STH was endothermic process. The regeneration experiments of STH using 0.1M Na2CO3 solution was successfully demonstrated multiple times without any significant effect on the initial adsorption capacity

Antibacterial activities of gel-derived Ag-TiO₂-SiO₂ nanomaterials under different light irradiation

Gel-derived Ag-TiO2-SiO2 nanomaterials were prepared by sol-gel process to determine their disinfection efficiency under UV-C, UV-A, solar irradiations and in dark condition. The surface morphology and properties of gel-derived Ag-TiO2-SiO2 nanomaterials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and BET specific surface area. The results showed that the average particle size of Ag-TiO2-SiO2 was around 10.9–16.3 nm. SiO2 mixed with TiO2 (the weight ratio of Si to Ti = 10:90) in the synthesis of Ag-TiO2-SiO2 by sol-gel process was found to increase the specific surface area of the obtained photocatalyst (164.5 m2g−1) as compared with that of commercial TiO2(P25) (53.1 m2g−1). Meanwhile, Ag doped in TiO2 (the mole ratio of Ag to TiO2 = 1%) decreased the specific surface area to 147.3 m2g−1. The antibacterial activities of gel-derived Ag-TiO2-SiO2 nanomaterials were evaluated by photocatalytic reaction against Escherichia coli bacteria (ATCC®25922). Ag-TiO2-SiO2 nanomaterials was observed to achieve higher disinfection efficiency than the catalyst without silver since both Ag nanoparticles and ions exhibit a strong antibacterial activity and promoted the e− – h+ separation of TiO2. The bactericidal activity of Ag-TiO2-SiO2 nanomaterial under light irradiation was superior to that under dark and only light. The reaction time to achieve a reduction by 6 log of bacteria of UV-C light alone and Ag-TiO2-SiO2 with UV-C light irradiation were 30 and 5 minutes, respectively. In addition, the superior synergistic effect of Ag-TiO2-SiO2 under both UV-A and solar light as compared to that under UV-C counterpart could be ascribed to the red-shift of the absorbance spectrum of the Ag doped TiO2-based catalyst