Integrated chemo- and biostratigraphic calibration of early animal evolution: Neoproterozoic-early Cambrian of southwest Mongolia

Five overlapping sections from the thick Neoproterozoic to early Cambrian sediments of western Mongolia were analysed to yield a remarkable carbon-isotope, strontium-isotope and small shellyfossil (SSF) record. Chemostratigraphy suggests that barren limestones of sequences 3 and 4, which lie above the two Maikhan Uul diamictites, are post-Sturtian but pre-Varangerian in age. Limestones and dolomites of sequence 5, with Boxonia grumulosa, have geochemical signatures consistent with a post-Varangerian (Ediacarian) age. A major negative δ13C anomaly (feature ‘W') in sequence 6 lies a shortdistance above an Anabarites trisulcatus Zone SSF asemblage with hexactinellid sponges, of probable late Ediacarian age. Anomaly ‘W' provides an anchor point for cross-correlation charts of carbon isotopes and small shelly fossils. Trace fossil assemblages with a distinctly Cambrian character first appear in sequence 8(Purella Zone), at the level of carbon isotopic feature ‘B', provisionally correlated with the upper part of cycle Z in Siberia. A paradox is found from sequence 10 to 12 in Mongolia: Tommotian-type SSFs continue to appear, accompanied by Nemakit-Daldynian/Tommotian-type 87Sr/86Sr ratios but by increasingly heavyδ13C values that cannot be matched in the Tommotian of eastern Siberia. The steady rate of generic diversification in Mongolia also contrasts markedly with the Tommotian ‘diversity explosion' in eastern Siberia, which occurs just above a major karstic emergence surface. One explanation is that sequences 10 to 12 in Mongolia preserve a pre-Tommotian portion of the fossil record that was missing or removed in easternSiberia. The Mongolian sections certainly deserve an important place in tracing the true course and timing of the ‘Cambrian radiation

Long-term operation of a multi-channel cosmic muon system based on scintillation counters with MRS APD light readout

A Cosmic Ray Test Facility (CRTF) is the first large-scale implementation of a scintillation triggering system based on a new scintillation technique known as START. In START, the scintillation light is collected and transported by WLS optical fibers, while light detection is performed by pairs of avalanche photodiodes with the Metal-Resistor-Semiconductor structure operated in the Geiger mode (MRS APD). START delivers 100% efficiency of cosmic muon detection, while its intrinsic noise level is less than 10^{-2} Hz. CRTF, consisting of 160 START channels, has been continuously operated by the ALICE TOF collaboration for more than 25 000 hours, and has demonstrated a high level of stability. Fewer than 10% of MRS APDs had to be replaced during this period.Comment: Proceedings of NDIP-2008. 8 pages, 8 figures, 6 reference

Signal Processing

Contains reports on three research projects.Joint Services Electronics Programs (U. S. Army, U. S. Navy, and U. S. Air Force) under Contract DA 28-043-AMC-02536(E

Extra-Curricular Activities as an Important Factor for Developing Subject Qualities of Future Engineers

We examine the need to develop the subjective qualities of students at technical universities based on the analysis of Russian and foreign research on future engineers’ training. We consider the peculiarities of future engineers’ educational process, based on the importance of extracurricular activities in the development of such qualities. The purpose of the study is to test the hypothesis about the effectiveness of developing the subjective qualities of future engineers by involving them in extracurricular activities that were formed at the initial stage. The paper describes a pedagogical experiment that includes three stages. The set of research methods includes analysis, synthesis, comparison, generalization, pedagogical observation, questionnaire survey, testing, conversation, expert assessments, and statistics. We present different directions and types of activities organized within the experimental work with pedagogical support. Besides, we give examples of extracurricular activities that contribute to the successful development and manifestation of the specified personal qualities in students. The paper contains evidence of the effectiveness of extracurricular student activities as a factor in developing subjective qualities

Second virial coefficients of light nuclear clusters and their chemical freeze-out in nuclear collisions

Here we develop a new strategy to analyze the chemical freeze-out of light (anti)nuclei produced in high energy collisions of heavy atomic nuclei within an advanced version of the hadron resonance gas model. It is based on two different, but complementary approaches to model the hard-core repulsion between the light nuclei and hadrons. The first approach is based on an approximate treatment of the equivalent hard-core radius of a roomy nuclear cluster and pions, while the second approach is rigorously derived here using a self-consistent treatment of classical excluded volumes of light (anti)nuclei and hadrons. By construction, in a hadronic medium dominated by pions, both approaches should give the same results. Employing this strategy to the analysis of hadronic and light (anti)nuclei multiplicities measured by ALICE at $\sqrt{s_{NN}} =2.76$ TeV and by STAR at $\sqrt{s_{NN}} =200$ GeV, we got rid of the existing ambiguity in the description of light (anti)nuclei data and determined the chemical freeze-out parameters of nuclei with high accuracy and confidence. At ALICE energy the nuclei are frozen prior to the hadrons at the temperature $T = 175.1^{+2.3}_{-3.9}$ MeV, while at STAR energy there is a single freeze-out of hadrons and nuclei at the temperature $T = 167.2 \pm 3.9$ MeV. We argue that the found chemical freeze-out volumes of nuclei can be considered as the volumes of quark-gluon bags that produce the nuclei at the moment of hadronization.Comment: 15 pages, 4 figures, 3 table

Paleogeographical reorganization of the Moscow Syneclise during the Severodvinian (Capitanian–Wuchiapingian) time based on isotopic (δ13C and δ18O) and paleontological data, Permian Period, East European Platform

© 2015, Pleiades Publishing, Ltd. Detailed studies of the isotope composition of carbon and oxygen (δ13C and δ18O) in sedimentary and pedogenic carbonates from the stratotype of the Severodvinian Stage of the Permian System (Sukhona River, Vologda Region) are provided. In these deposits, the value of δ13C is the greatest for the Upper Permian and Lower Triassic of European Russia. This level is correlated with the Kamura isotopic geochemical event in the marine sections of Panthalassa and the Tethyan Region, which was connected with a fall in temperature during the Early–Middle Capitanian. Variations of δ18O in the Severodvinian Stage also support the concept of general fall in temperature. The lower part of the Severodvinian Stage is characterized by carbonates with a very heavy oxygen isotope composition, about 32–34‰ SMOW, which accumulated during evaporitization of a large basin. In the upper part of the Severodvinian Stage, the value of δ18O rhythmically changes from 22–24‰ SMOW to 34‰, naturally following the cyclicity established based on sedimentological features. The minimal values of δ18O are episodes of a significant decrease in salinity as a result of decreased temperature and humidification. The highest values of the isotope content of oxygen correspond to the episodes of short warming and evaporitization of shallow lakes. A general decrease in average annual temperature in the middle of the Severodvinian Age was associated with activation of rivers and intensification of terrigenous sedimentation, which resulted in replacement of the basin facies by alluvial facies and to wide occurrence of aerial and subaerial conditions. Simultaneously, in the latter half of the Severodvinian Age on the East European Platform, there was essential renewal of assemblages of tetrapods, fishes, ostracodes, mollusks, and plants

Passive mode locking of a Tm,Ho:KY(WO4)(2) laser around 2 μm

We report the first demonstration, to our knowledge, of passive mode locking in a Tm3+, Ho3+-codoped KYWO42 laser operating in the 2000-2060 nm spectral region. An InGaAsSb-based quantum well semiconductor saturable absorber mirror is used for the initiation and stabilization of the ultrashort pulse generation. Pulses as short as 3.3 ps were generated at 2057 nm with average output powers up to 315 mW at a pulse repetition frequency of 132 MHz for 1.15 W of absorbed pump power at 802 nm from a Ti:sapphire laser

Baikal-GVD: status and prospects

Baikal-GVD is a next generation, kilometer-scale neutrino telescope under construction in Lake Baikal. It is designed to detect astrophysical neutrino fluxes at energies from a few TeV up to 100 PeV. GVD is formed by multi-megaton subarrays (clusters). The array construction started in 2015 by deployment of a reduced-size demonstration cluster named "Dubna". The first cluster in its baseline configuration was deployed in 2016, the second in 2017 and the third in 2018. The full scale GVD will be an array of ~10000 light sensors with an instrumented volume of about 2 cubic km. The first phase (GVD-1) is planned to be completed by 2020-2021. It will comprise 8 clusters with 2304 light sensors in total. We describe the design of Baikal-GVD and present selected results obtained in 2015-2017.Comment: 9 pages, 8 figures. Conference proceedings for QUARKS201