Russian Academy of Sciences

About: Russian Academy of Sciences is a government organization based out in Moscow, Russia. It is known for research contribution in the topics: Catalysis & Laser. The organization has 272615 authors who have published 417512 publications receiving 4538835 citations. The organization is also known as: RAS & RAN.

Detection of the aromatic molecule benzonitrile (c-C6H5CN) in the interstellar medium.

Abstract: Polycyclic aromatic hydrocarbons and polycyclic aromatic nitrogen heterocycles are thought to be widespread throughout the universe, because these classes of molecules are probably responsible for the unidentified infrared bands, a set of emission features seen in numerous Galactic and extragalactic sources. Despite their expected ubiquity, astronomical identification of specific aromatic molecules has proven elusive. We present the discovery of benzonitrile (c-C6H5CN), one of the simplest nitrogen-bearing aromatic molecules, in the interstellar medium. We observed hyperfine-resolved transitions of benzonitrile in emission from the molecular cloud TMC-1. Simple aromatic molecules such as benzonitrile may be precursors for polycyclic aromatic hydrocarbon formation, providing a chemical link to the carriers of the unidentified infrared bands.

Infrared-modified gravities and massive gravitons

Abstract: We review some theoretical and phenomenological aspects of massive gravities in 4 dimensions. We start from the Fierz–Pauli theory with Lorentz-invariant mass terms and then proceed to Lorentz-violating masses. Unlike the former theory, some models with Lorentz violation have no pathologies in the spectrum in flat and nearly flat backgrounds and lead to an interesting phenomenology.

Remobilisation of the continental lithosphere by a mantle plume: major-, trace-element, and Sr-, Nd-, and Pb-isotope evidence from picritic and tholeiitic lavas of the Noril'sk District, Siberian Trap, Russia

Abstract: The Late Permian to Early Triassic Siberian Traps have been sampled by drill core (core SG-9) and from surface exposure (section 1F) in the Noril'sk region of the Siberian Platform, Russia. Combined major, trace element, and Nd-, Sr-, and Pb-isotope data on selected samples through the Siberia Trap, offer new chemostratigraphic criteria for the identification and characterisation of two fundamentally different magma types and 9 of the 11 formations of lava developed near Noril'sk. A Lower Sequence of sub-alkalic basalts, tholeiites, and picritic basalts (upwards these are the Ivakinsky, Syverminsky, and Gudchichinsky formations) are overlain by an Upper Sequence of picritic basalts and tholeiites interbedded with tuffs (upwards, these are the Khakanchansky, Tuklonsky, Nadezhdinsky, Morongovsky, Mokulaevsky and Kharayelakhsky formations).The Gudchichinsky and Tuklonsky formations contain both picritic and tholeiitic lavas. The Tuklonsky formation tholeiites and picrites have moderate Gd/Yb (1.6–1.8), low TiO2 (0.45–0.95 wt%), a significant negative Ta and Nb anomaly (Nb/La =0.42–0.57) and unradiogenic Nd (ɛ Nd CHUR = to -4.6). In contrast, both the Gudchichinsky formation tholeiites and picrites have high Gd/Yb (2.3–3.1), and TiO2 (1.2–2.3 wt%), no significant Nb or Ta anomaly (Nb/La =0.8–1.1), and radiogenic Nd (ɛ Nd CHUR = to 7.3). The low-Ti and Nb/La, high La/Sm, and unradiogenic Nd-isotope signatures of the picritic Tuklonsky formation lavas and the tholeiitic lavas of the Upper Sequence are characteristic of magmas strongly influenced by material from the continental lithosphere, whereas the high-Ti and Nb/La, low La/Sm and radiogenic Nd-isotope signatures of the Lower Sequence are more comparable to deeper asthenospheric mantle-plume generated lavas similar to oceanic island basalts. The lavas overlying the Tuklonsky formation have mg-numbers of 0.63 to 0.68, and are more evolved than the Tuklonsky (Mg-number < 0.62) and have more radiogenic ɛ Nd CHUR (Tuklonsky:-0.03 to-4.66; Mokulaevsky: + 0.60 to + 1.61), but have many of the incompatible trace element features of the Tuklonsky sky type magma. These lavas show a progressive upwards decline in SiO2 (55–49 wt%), La/Sm (4.6–2.0), and ɛ UR Sr ( + 67 to + 13) which has previously been attributed to a decrease in the proportion of crustal material contributed to the magma. This paper explores and alternative model where a component of the crustal contribution might be derived from within an ancient region of the mantle lithosphere as recycled sediment rather than from the overlying continental crust.

The Formation of Human Populations in South and Central Asia

Abstract: By sequencing 523 ancient humans, we show that the primary source of ancestry in modern South Asians is a prehistoric genetic gradient between people related to early hunter-gatherers of Iran and Southeast Asia. After the Indus Valley Civilization's decline, its people mixed with individuals in the southeast to form one of the two main ancestral populations of South Asia, whose direct descendants live in southern India. Simultaneously, they mixed with descendants of Steppe pastoralists who, starting around 4000 years ago, spread via Central Asia to form the other main ancestral population. The Steppe ancestry in South Asia has the same profile as that in Bronze Age Eastern Europe, tracking a movement of people that affected both regions and that likely spread the distinctive features shared between Indo-Iranian and Balto-Slavic languages.