לוח שנה משולב

The Acheulo-Yabrudian Cultural Complex (AYCC, ~420,000-200,000 years ago) is a local Levantine entity, characterized by a set of innovative human cultural and biological adaptations, including the habitual use of fire, technological innovations such as blade and Quina scraper production, and more. Qesem Cave (QC, central Israel) is one of the key sites of the AYCC. I will present the results of two recent studies, exploring the rich lithic assemblages yielded from this important site.
The first combines macroscopic classification of flint artefacts with a geological survey and petrographic and geochemical analyses, aimed at identifying patterns of flint acquisition and use. The results show that local Turonian flint was often brought and used at the cave, while flint from other, non-Turonian origins, was also used in noteworthy proportions, in specific categories, implying selectivity in flint procurement and exploitation through time.
The second study combines Raman spectroscopy and artificial intelligence (AI) to build temperature predictive models, aimed at identifying the temperatures to which flint artefacts were exposed. The results show that blades were heated at lower median temperatures (259℃) compared to flakes (413℃), suggesting the intentional and controlled heat treatment of flint specifically for blade production, more than 300,000 years ago.
Both datasets and their implications will be discussed in a broader perspective.

For the past two years we have been involved in the synthesis and characterization of new Uranium-based endohedral fullerenes and have obtained X-Ray crystal structures for several of these compounds. Some are mono-uranium species, U@C2n, while some are di-uranium compounds (see structure at the left), U2@C2n.1 Very recently we isolated two new mono-uranium compounds that violate the Isolated Pentagon Rule (IPR) with a C76 and a C80 cage possessing fused five-membered rings (pentalenes) on their surfaces.2 Still other endohedral structures are much more interesting and totally unanticipated, with formula U2X@C2n, where X= C, O, S or N and 2n= 72, 78 or 80, which reveal interesting metal-cage interactions and totally unprecedented clusters trapped inside. Some of the carbide compounds have been crystallized and the encapsulated U2C cluster (in U=C=U@C80) exhibits unprecedented bonding with totally unanticipated properties (see structure to the right).3
Finally, we have found that bis-porphyrin capsules exhibit exquisitely selective supramolecular binding for several of these uranium-based endohedral fullerene compounds.4
The synthesis, purification and characterization of these interesting endohedral fullerenes will be presented and discussed, along with very recent results about uranium-based endohedrals.

References
1. Zhang, X.; Wang, Y.; Morales-Martínez, R.; Zhong, J.; de Graaf, C.; Rodríguez-Fortea, A.; Poblet, J. M.; Echegoyen, L.; Feng, L.; Chen, N., J. Am. Chem. Soc. 2018, 140 (11), 3907-3915.
2. Cai, W.; Abella, L.; Zhuang, J.; Zhang, X.; Feng, L.; Wang, Y.; Morales-Martínez, R.; Esper, R.; Boero, M.; Metta-Magaña, A.; Rodríguez-Fortea, A.; Poblet, J. M.; Echegoyen, L.; Chen, N., J. Am. Chem. Soc. 2018, 140 (51), 18039-18050.
3. Zhang, X.; Li, W.; Feng, L.; Chen, X.; Hansen, A.; Grimme, S.; Fortier, S.; Sergentu, D.-C.; Duignan, T. J.; Autschbach, J.; Wang, S.; Wang, Y.; Velkos, G.; Popov, A. A.; Aghdassi, N.; Duhm, S.; Li, X.; Li, J.; Echegoyen, L.; Schwarz, W. H. E.; Chen, N., Nature Comm. 2018, 9 (1), 2753.
4. Fuertes-Espinosa, C.; Gómez-Torres, A.; Morales-Martínez, R.; Rodríguez-Fortea, A.; García-Simón, C.; Gándara, F.; Imaz, I.; Juanhuix, J.; Maspoch, D.; Poblet, J. M.; Echegoyen, L.; Ribas, X., Angew. Chem. Int. Ed. 2018, 57 (35), 11294-11299.

At high accretion rates, the outward force of radiation pressure generated by energy released by infalling matter can exceed the inward pull of gravity.  Such super-Eddington accretion flows occur in many systems, such as the inner regions of quasars and luminous AGN, ultra-luminous X-ray sources (ULXs), and tidal disruption events.  Understanding such flows is important not only for interpreting the spectra and variability of these sources, but also to predict the rate of growth of black holes in the early universe, and to quantify energy and momentum feedback into the medium surrounding the black hole, a process likely to be important in galaxy formation.  New results from a study of the magnetohydrodynamics of luminous accretion flows, in which radiation pressure dominates, will be presented. Our results reveal new physical effects, such as turbulent transport of radiation energy, that require extension of standard thin-disk models.  We discuss the implications of our results for the astrophysics of accreting black holes.