96 research outputs found
Palynostratigraphical review of the K–Pg boundary from the Ibero-Armorican Island: New data from the Maastrichtian dinosaur outcrop Veracruz 1 (Pyrenees, NE Iberian Peninsula)
The palynostratigraphy of the K-Pg boundary interval in SW Europe has been a subject of ongoing debate, despite numerous palynological studies in the region. To address this, we review previous publications and conduct analysis of new deposits to establish a palynostratigraphical chart. A total of 40 palynological studies within the Normapolles palynological province were reexamined to elucidate key taxa restricted to the Cretaceous (K-taxa), to the Maastrichtian-Danian interval (KPg-taxa) and those restricted to the Paleogene (Pg-taxa). Eventually, we propose 18 key taxa to differentiate a Maastrichtian from a Danian palynological assemblage within the Normapolles Province. Afterward, a palynostratigraphical analysis was carried out in Veracruz 1 (Aragonese Pyrenees), one of the more modern dinosaurbearing sites of Europe. The palynological assemblage corresponded to an upper Maastrichtian age and was composed by pteridophyte spores, gymnosperms, angiosperms, dinoflagellate cysts, algae, and fungal spores. It was predominated by angiosperm pollen (Liliaceae, post-Normapolles, and triporate pollen). The plant communities in Veracruz 1 seem to be characterized by plants from an open coastal forest prevailed by Liliaceae flowering herbs and Juglandaceae/Myricaceae dicotyledonous trees and shrubs thriving in temperate-warm paleoclimate. The Gondwanan botanical influence was also supported by the presence of Bacumorphomonocolpites sp., as this taxon was previously recorded in other upper Maastrichtian deposits from Europe.Agencia Estatal de Investigación | Ref. PID2021-122612OB-I00Xunta de Galicia | Ref. ED431C-2019/28Xunta de Galicia | Ref. ED481A-2020/175Universidad Nacional Autónoma de México | Ref. UNAM-DGAPA 2023–2024Swedish Research Council | Ref. VR 2022-03920Universidade de Vigo/CISU
Understanding the role of Ti-rich domains in the stabilization of gold nanoparticles on mesoporous silica-based catalysts
The preparation and stabilization of gold nanoparticles with a precise control of size and dispersion is highly attractive for a variety of applications, and a key aspect is thermal stability of the nanoparticles. This paper focuses on understanding the effect of TiO2-based nanodomains, dispersed on mesoporous silicas, and how they control gold nanoparticle stability. The anatase domains have been incorporated through two different strategies: co-hydrolysis of Si and Ti reagents that directly form the mesoporous material through self-assembling with surfactant micelles, or the post-impregnation of the mesosporous silica with Ti(acac)2. Both strategies lead to different incorporation of the anatase domains: partially embedded inside the silica walls, or occupying the mesopores. We have observed that the inclusion in the pores favors the stability of the final material due to a more favorable gold-support interaction and also due to a stabilizing effect associated with a scaffold effect of the anatase crystals, which hinders the collapse of the mesostructure
Operando Spectroscopy of the Gas-Phase Aldol Condensation of Propanal over Solid Base Catalysts
Palynostratigraphical review of the K–Pg boundary from the Ibero-Armorican Island: New data from the Maastrichtian dinosaur outcrop Veracruz 1 (Pyrenees, NE Iberian Peninsula)
Abstract
The palynostratigraphy of the K–Pg boundary interval in SW Europe has been a subject of ongoing debate, despite numerous palynological studies in the region. To address this, we review previous publications and conduct analysis of new deposits to establish a palynostratigraphical chart. A total of 40 palynological studies within the Normapolles palynological province were reexamined to elucidate key taxa restricted to the Cretaceous (K-taxa), to the Maastrichtian–Danian interval (KPg-taxa) and those restricted to the Paleogene (Pg-taxa). Eventually, we propose 18 key taxa to differentiate a Maastrichtian from a Danian palynological assemblage within the Normapolles Province. Afterward, a palynostratigraphical analysis was carried out in Veracruz 1 (Aragonese Pyrenees), one of the more modern dinosaur-bearing sites of Europe. The palynological assemblage corresponded to an upper Maastrichtian age and was composed by pteridophyte spores, gymnosperms, angiosperms, dinoflagellate cysts, algae, and fungal spores. It was predominated by angiosperm pollen (Liliaceae, post-Normapolles, and triporate pollen). The plant communities in Veracruz 1 seem to be characterized by plants from an open coastal forest prevailed by Liliaceae flowering herbs and Juglandaceae/Myricaceae dicotyledonous trees and shrubs thriving in temperate-warm paleoclimate. The Gondwanan botanical influence was also supported by the presence of Bacumorphomonocolpites sp., as this taxon was previously recorded in other upper Maastrichtian deposits from Europe
High-temperature stable gold nanoparticle catalysts for application under severe conditions: the role of TiO2 nanodomains in structure and activity
Metal nanoparticles with precisely controlled size are highly attractive for heterogeneous catalysis. However, their poor thermal stability remains a major concern in their application at realistic operating conditions. This paper demonstrates the possibility of synthesizing gold nanoparticles with exceptional thermal stability. This has been achieved by using a simple conventional deposition–precipitation technique. The material employed as catalyst consists of gold supported on a TiO2-impregnated SiO2 bimodal mesoporous support. The resulting material shows gold nanoparticles with a narrow size distribution around 3.0 nm, homogeneously dispersed over the TiO2/SiO2 material. Most interestingly, the gold nanoparticles show exceptional thermal stability; calcination temperatures as high as 800 °C have been employed, and negligible changes in the gold particle size distribution are apparent. Additionally, the presence of an amorphous titanium silicate phase is partially preserved, and these factors lead to remarkable activity to catalyze a range of oxidation reactions
Mental well-being of the general population : direct and indirect effects of socioeconomic, relational and health factors
Altres ajuts: Fondo Europeo de Desarrollo Regional (FEDER).Purpose: The aim of this study was to analyse the association between individual mental well-being and social, economic, lifestyle and health factors. Methods: Cross-sectional study on a representative sample of 13,632 participants (> 15y/o) from the Catalan Health Interview Survey 2013-2016 editions. Mental well-being was assessed with the Warwick-Edinburg Mental Well-being Scale (WEMWBS). Linear regressions were fitted to associate well-being and sociodemographic, relational, lifestyle and health variables according to minimally sufficient adjustment sets identified using directed acyclic graphs. Predictors entered the model in blocks of variable types and analysed individually. Direct and total effects were estimated. Results: Health factors significantly contributed to mental well-being variance. Presence of a mental disorder and self-reported health had the largest effect size (eta = 13.4% and 16.3%). The higher individual impact from a variable came from social support (β = − 12.8, SE = 0.48, eta = 6.3%). A noticeable effect gradient (eta = 4.2%) from low to high mental well-being emerged according to economic difficulties (from β = 1.59, SE = 0.33 for moderate difficulties to β = 6.02 SE = 0.55 for no difficulties). Younger age (β = 5.21, SE = 0.26, eta = 3.4%) and being men (β = 1.32, SE = 0.15, eta = 0.6%) were associated with better mental well-being. Direct gender effects were negligible. Conclusions: This study highlights health and social support as the most associated factors with individual mental well-being over socioeconomic factors. Interventions and policies aimed to these factors for health promotion would improve population mental well-being
Pelvic and femoral anatomy of the Allodaposuchidae (Crocodyliformes, Eusuchia) from the Late Cretaceous of Lo Hueco (Cuenca, Spain)
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