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Carbonatites are rare igneous rocks that host the largest resources of REE and Nb, yet, their genesis and evolution are far from clear. The leading models of carbonatite formation are the direct melting of carbonate-bearing peridotites, silicate-carbonatite liquid immiscibility, and fractionation of carbonated silicate melts. The validity of these models has never been robustly addressed through combining the available experimental results with the natural rock record. We thus re-evaluate the presently 633 alleged carbonatite occurrences including carbonatite type, bulk composition, mineralogy, and field exposure, followed by a review of experimental data pertinent to carbonatite genesis and evolution. Based on the available data, 454 carbonatite occurrences are magmatic, of which 87 without and 338 with spatially associated alkaline magma, 9 with kimberlites, and 20 with ultramafic cumulates only. Eighty-four percent of the magmatic occurrences contain calcite carbonatite (of which 1/3 also contain dolomite carbonatite), only 9% have dolomite but not calcite carbonatite, the incidence of dolomite carbonatite being similar for occurrences with or without associated silicate magmas. Available experimental data show that crystallization of calcite, dolomite, ankerite, and siderite at crustal conditions requires moderately alkaline and/or hydrous carbonate melts with ≥20 to 25 wt % (Na,K)2CO3 + H2O. It follows that carbonatite rocks, poor in these elements, are at best magmatic cumulates (if not carbo- or hydrothermal) that lost these ephemeral components. Carbonatitic melts could form in the lithospheric mantle, but these are always dolomitic and cannot deviate from close-to-minimum compositions when rising, their strong adiabatic cooling keeping them on the solidus until they decompose to olivine, clinopyroxene (cpx), and CO2 when reaching <2.1 GPa, i.e. the carbonated peridotite solidus ledge, which renders their extraction from the mantle highly unlikely. Furthermore, dolomitic carbonate melts crystallize periclase + calcite at crustal conditions. Only when containing ≥15 wt % (Na,K)2O + H2O they may crystallize dolomite and form dolomitic carbonatites. This value is far above the 2 to 5 wt % (Na,K)2O of mantle-derived carbonatitic melts. Liquid immiscibility from CO2-bearing close-to-natural melilititic, nephelinitic, and phonolitic melts requires 10 to 15 wt % Na2O + K2O in the silicate melt, increasing with SiO2. Extensive differentiation of primitive alkaline melilititic or basanitic parents is hence required to achieve immiscibility. The experimental data show that evolved nephelinites and phonolites unmix calcic carbonatitic melts, while melilitites and undifferentiated nephelinites with >4 wt % MgO may also unmix dolomitic carbonatitic melts. The latter may hence arise from liquid immiscibility or develop through fractionation from calcic carbonatitic melts. Finally, carbonatites may also derive through fractionation of CO2-rich ultramafic melts, but a continuous increase in dissolved CO2 from a carbonated silicate melt to a carbonatitic melt requires ≥3 GPa. We conclude that the combination of the natural rock record with melting and crystallization phase relations excludes a direct mantle origin for almost all carbonatites found in the crust. Instead, their vast majority forms through immiscibility from an alkali-rich differentiated silicate melt that stems from a mantle-derived alkaline parent, consistent with the common spatial association with alkaline complexes and similar isotopic compositions of carbonatite and alkaline silicate rocks. Direct fractionation from silicate melts may occur for kimberlitic or ultramafic lamprophyric melts, but only at ≥3 GPa, i.e. within the lithospheric mantle. To make progress in this field, we suggest a more rigorous distinction of magmatic and carbo- or hydrothermal carbonatite rocks in each occurrence, and to focus on mineral compositions in the carbonatite and associated silicate magmas, as bulk rocks are at best cumulative in nature. Additional experimental work to understand the role of alkalis and H2O in the formation and evolution of carbonatites, in particular crystallization and fluid saturation at crustal conditions, will be essential to provide a more complete understanding of carbonatite petrogenesis. [ABSTRACT FROM AUTHOR]

Integrating domestic robots into the lives of older adults reflects a possible solution to provide adequate caregiving to an increasingly ageing population. Still, it is unclear how older adults perceive domestic robots and whether they are willing to adopt them into their homes. This paper analyses the attitudes of older adults towards domestic robots by proving the results of a qualitative study conducted during an experience of co-designing a robotic prototype, addressing 30 community-dwelling over-65s who are residents in Genoa, Italy. Our results show how attitudes toward the robot differ both due to individual and structural characteristics, but especially owing to generational and cultural factors, particularly between younger-old baby Boomers and olderold respondents. In conclusion, our study provides interesting suggestions for designers and engineers to consider generational differences as predictive factors of acceptance of domestic robots by senior end-users. [ABSTRACT FROM AUTHOR]

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Background: Frailty has been recognized as potential surrogate of biological age and relevant risk factor for COVID‐19 severity. Thus, it is important to explore the frailty trajectories during COVID‐19 pandemic and understand how COVID‐19 directly and indirectly impacts on frailty condition. Methods: We enrolled 217 community‐dwelling older adults with available information on frailty condition as assessed by multidimensional frailty model both at baseline and at one‐year follow‐up using Multidimensional Prognostic Index (MPI) tools. Pre‐frail/frail subjects were identified at baseline as those with MPI score >0.33 (MPI grades 2–3). Frailty worsening was defined by MPI difference between 12 months follow‐up and baseline ≥0.1. Multivariable logistic regression was modelled to identify predictors of worsening of frailty condition. Results: Frailer subjects at baseline (MPI grades 2–3 = 48.4%) were older, more frequently female and had higher rates of hospitalization and Sars‐CoV‐2 infection compared to robust ones (MPI grade 1). Having MPI grades 2–3 at baseline was associated with higher risk of further worsening of frailty condition (adjusted odd ratio (aOR): 13.60, 95% confidence interval (CI): 4.01–46.09), independently by age, gender and Sars‐CoV‐2 infection. Specifically, frail subjects without COVID‐19 (aOR: 14.84, 95% CI: 4.26–51.74) as well as those with COVID‐19 (aOR: 12.77, 95% CI: 2.66–61.40, p = 0.001) had significantly higher risk of worsening of frailty condition. Conclusions: Effects of COVID‐19 pandemic among community‐dwelling frailer individuals are far beyond the mere infection and disease, determining a significant deterioration of frailty status both in infected and non‐infected subjects. [ABSTRACT FROM AUTHOR]