Possibility of hypothetical stable micro black hole production at future 100 TeV collider

We study the phenomenology of TeV-scale black holes predicted in theories with large extra dimensions, under the further assumption that they are absolutely stable. Our goal is to present an exhaustive analysis of safety of the proposed 100 TeV collider, as it was done in the case of the LHC. We consider the theories with different number of extra dimensions and identify those for which a possible accretion to macroscopic size would have timescales shorter than the lifetime of the Solar system. We calculate the cross sections of the black hole production at the proposed 100 TeV collider, the fraction of the black holes trapped inside the Earth and the resulting rate of capture inside the Earth via an improved method. We study the astrophysical consequences of stable micro black holes existence, in particular its influence on the stability of white dwarfs and neutron stars. We obtain constraints for the previously unexplored range of higher-dimensional Planck mass values. Several astrophysical scenarios of the micro black hole production, which were not considered before, are taken into account. Finally, using the astrophysical constraints we consider the implications for future 100 TeV terrestrial experiments. We exclude the possibility of the charged stable micro black holes production.Comment: 11 pages, 8 figures, accepted for publication in EPJ

Surgeries on periodic links and homology of periodic 3-manifolds

We show that a closed orientable 3-manifold M admits an action of Z_p with fixed point set S^1 iff M can be obtained as the result of surgery on a p-periodic framed link L and Z_p acts freely on the components of L. We prove a similar theorem for free Z_p-actions. As an interesting application, we prove the following, rather unexpected result: for any M as above and for any odd prime p, H_1(M, Z_p)\ne Z_p. We also prove a similar criterion of 2-periodicity for rational homology 3-spheres.Comment: 3 figure

Stone Cutting in the Urals: Towards the Question of Regional Cultural Features

This study considers the phenomenon of the Ural school of artistic processing of colored ornamental stone as an educational process. Education in the field of stonecarving art in the Urals, despite following the all-Russian principles for the development of an art school, is a unique phenomenon, due to geographical and socio-cultural factors. The training of stone cutters arose along with the need to process stone directly in the vicinity of material extraction. The educational process was developed in the Soviet era as a means to gather personnel for stone-cutting production. More recently, the development of this artform has produced a new approach in the education of specialists in the artistic processing of stone. Both the traditions of the educational process and the problems of today are examined, revealing the general picture of the development of the trend. The study, regarding the development of a separate direction of the educational process, will supplement and concretize the general picture of the development of not only the Ural, but also the domestic art school. Keywords: educational process, Ural stone-cutting school, artistic processing of colored ornamental stone, educational institutio

Nanostructured Hybrids Based on Tantalum Bromide Octahedral Clusters and Graphene Oxide for Photocatalytic Hydrogen Evolution

[EN] The generation of hydrogen (H2) using sunlight has become an essential energy alternative for decarbonization. The need for functional nanohybrid materials based on photo- and electroactive materials and accessible raw materials is high in the field of solar fuels. To reach this goal, single-step synthesis of {Ta6Bri12}@GO (GO = graphene oxide) nanohybrids was developed by immobilization of [{Ta6Bri12}Bra2(H2O)a4]·4H2O (i = inner and a = apical positions of the Ta6 octahedron) on GO nanosheets by taking the advantage of the easy ligand exchange of the apical cluster ligands with the oxygen functionalities of GO. The nanohybrids were characterized by spectroscopic, analytical, and morphological techniques. The hybrid formation enhances the yield of photocatalytic H2 from water with respect to their precursors and this is without the presence of precious metals. This enhancement is attributed to the optimal cluster loading onto the GO support and the crucial role of GO in the electron transfer from Ta6 clusters into GO sheets, thus suppressing the charge recombination. In view of the simplicity and versatility of the designed photocatalytic system, octahedral tantalum clusters are promising candidates to develop new and environmentally friendly photocatalysts for H2 evolution.This research was funded by Ministerio de Ciencia e Innovación (MICINN), grant number PGC2018-099744. Parts of this research dealing with metal cluster synthesis and characterization received funding from project RTI2018-096399-A-I00 funded by MCIN/AEI/10.13039/501100011033/ and ¿ERDF A way of making Europe¿. J.S.H. gratefully acknowledges the Consejo Superior de Investigaciones Científicas (CSIC) and Generalitat Valenciana (GVA), Programa Santiago Grisolía, grant number GRISOLIA/2021/054. M.S. received financial support by the Russian Foundation for Basic Research (grant number 20-33-90010) and the Ministry of Science and Higher Education of the Russian Federation (grant number 121031700313¿8). The APC was funded by this journal.Hernandez-Niño, JS.; Shamsurin, M.; Puche Panadero, M.; Sokolov, MN.; Feliz Rodriguez, M. (2022). Nanostructured Hybrids Based on Tantalum Bromide Octahedral Clusters and Graphene Oxide for Photocatalytic Hydrogen Evolution. Nanomaterials. 12(20). https://doi.org/10.3390/nano12203647122

Phosducin regulates the expression of transducin betagamma subunits in rod photoreceptors and does not contribute to phototransduction adaptation.

For over a decade, phosducin's interaction with the betagamma subunits of the G protein, transducin, has been thought to contribute to light adaptation by dynamically controlling the amount of transducin heterotrimer available for activation by photoexcited rhodopsin. In this study we directly tested this hypothesis by characterizing the dark- and light-adapted response properties of phosducin knockout (Pd- / -) rods. Pd- / - rods were notably less sensitive to light than wild-type (WT) rods. The gain of transduction, as measured by the amplification constant using the Lamb-Pugh model of activation, was 32% lower in Pd- / - rods than in WT rods. This reduced amplification correlated with a 36% reduction in the level of transducin betagamma-subunit expression, and thus available heterotrimer in Pd- / - rods. However, commonly studied forms of light adaptation were normal in the absence of phosducin. Thus, phosducin does not appear to contribute to adaptation mechanisms of the outer segment by dynamically controlling heterotrimer availability, but rather is necessary for maintaining normal transducin expression and therefore normal flash sensitivity in rods

Searching for GUT-scale QCD Axions and Monopoles with a High Voltage Capacitor

The QCD axion has been postulated to exist because it solves the strong CP problem. Furthermore, if it exists axions should be created in the early Universe and could account for all the observed dark matter. In particular, axion masses of order $10^{-10}$ to $10^{-7}$ eV correspond to axions in the vicinity of the GUT-scale. In this mass range many experiments have been proposed to search for the axion through the standard QED coupling parameter $g_{a\gamma\gamma}$. Recently axion electrodynamics has been expanded to include two more coupling parameters, $g_{aEM}$ and $g_{aMM}$, which could arise if heavy magnetic monopoles exist. In this work we show that both $g_{aMM}$ and $g_{aEM}$ may be searched for using a high voltage capacitor. Since the experiment is not sensitive to $g_{a\gamma\gamma}$, it gives a new way to search for effects of heavy monopoles if the GUT-scale axion is shown to exist, or to simultaneously search for both the axion and the monopole at the same time