4,224 research outputs found
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 Ξ΄13C anomaly (feature βW') in sequence 6 lies a shortdistance above an Anabarites trisulcatus Zone SSF asemblage with hexactinellid sponges, of probable late Ediacarian age. Anomaly βW' 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 βB', 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 heavyΞ΄13C 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 βdiversity 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 βCambrian radiation
Π Π΅Π³Π΅Π½Π΅ΡΠ°ΡΠΈΠ²Π½ΡΠΉ ΡΡΠΈΠ»ΠΈΡΠ΅Π»Ρ ΡΠΈΡΠΏΠΈΡΠΎΠ²Π°Π½Π½ΡΡ ΠΈΠΌΠΏΡΠ»ΡΡΠΎΠ² Π½Π° ΠΊΡΠΈΡΡΠ°Π»Π»Π΅ Yb3+:LuAlO3 Ρ ΡΡΠΈΠ»Π΅Π½ΠΈΠ΅ΠΌ ΠΎΡΠ΄Π΅Π»ΡΠ½ΡΡ ΡΠΏΠ΅ΠΊΡΡΠ°Π»ΡΠ½ΡΡ ΠΊΠΎΠΌΠΏΠΎΠ½Π΅Π½Ρ Π΄Π»Ρ ΠΏΡΠΈΠΌΠ΅Π½Π΅Π½ΠΈΠΉ Π² ΡΠ΅ΡΠ°Π³Π΅ΡΡΠΎΠ²ΠΎΠΉ ΠΎΠ±Π»Π°ΡΡΠΈ ΡΠΏΠ΅ΠΊΡΡΠ°
Compact diode-pumped chirped pulse regenerative amplifier systems with pulse repetition rate of hundreds kilohertz based on Yb3+-doped crystals are of practical importance for wide range of applications such as materials processing, medicine, scientific research, etc. The aim of this work was to study the Yb3+:LuAlO3 crystal based dual wavelength chirped pulse regenerative amplifier. Perovskite-like aluminate crystals have unique spectroscopic properties that allowed to use amplifier active element gain spectrum as an amplitude filter for amplified pulse spectrum and even obtained dual wavelength amplification without any additional components. In our work a simple way to obtain dual-wavelength operation of chirped pulse regenerative amplifier by using the active medium gain spectrum as an amplitude filter for the formation of the amplified pulses spectrum demonstrated for the first time to our knowledge. Maximum output power of 5.4 W of chirped pulses (3.8 W after compression) and optical-to-optical efficiency of 22.5 % have been obtained for Yb:LuAP E//b-polarization at 200 kHz repetition rate. Compressed amplified pulse duration was about 708 fs while separate spectral components durations were 643 fs and 536 fs at 1018.3 nm and 1041.1 nm central wavelengths, respectively. Performed investigations show high potential of Yb3+:LuAP crystals as active elements of compact diode pumped chirped pulse regenerative amplifiers
ΠΡΡΠΎΠΊΠΎΠΌΠΎΡΠ½ΡΠΉ Π»Π°Π·Π΅Ρ Π½Π° ΠΊΡΠΈΡΡΠ°Π»Π»Π΅ Yb3+:YAlO3, ΡΠ°Π±ΠΎΡΠ°ΡΡΠΈΠΉ Π² ΡΠ΅ΠΆΠΈΠΌΠ΅ ΡΠΈΠ½Ρ ΡΠΎΠ½ΠΈΠ·Π°ΡΠΈΠΈ ΠΌΠΎΠ΄ Π½Π° ΠΎΡΠ½ΠΎΠ²Π΅ ΠΏΠΎΠ»ΡΠΏΡΠΎΠ²ΠΎΠ΄Π½ΠΈΠΊΠΎΠ²ΡΡ Π·Π΅ΡΠΊΠ°Π» Ρ Π½Π°ΡΡΡΠ°ΡΡΠΈΠΌΡΡ ΠΏΠΎΠ³Π»ΠΎΡΠΈΡΠ΅Π»Π΅ΠΌ
Yttrium aluminium perovskite YAlO3 (YAP) crystal, doped with rare-earth ions, has been extensively studied as a diode-pumped laser host material. The wide interest to rare-earth ions doped YAP crystals is explained by its good thermal and mechanical properties, high natural birefringence, widely used Czochralski growth method. The aim of this work was to study the Yb3+:YAlO3 crystal as an active medium for high power mode-locked laser. Yb3+-doped perovskite-like aluminate crystals have unique spectroscopic and thermooptical properties that allowed using these crystals as an active medium of high power continuous wave (CW) and modelocked (ML) bulk lasers with diode pumping. In our work spectroscopic properties of Yb:YAP crystal and laser characteristics in CW and ML regimes are investigated. Maximum output power of 4 W with optical-to-optical efficiency of 16.3 % and 140 fs pulse duration have been obtained for Yb:YAP E //c-polarization with 10 % output coupler transmittance. Tunability range as wide as 67 nm confirms high promise of using Yb:YAP crystal for lasers working in wide spectral range
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
Probing invisible vector meson decay mode with hadronic beam in the NA64 experiment at SPS/CERN
We test a novel idea of using a beam in the fixed-target experiments
to search for New Physics in the events with missing energy. Bounds for
invisible vector meson decay were derived, analyzed, and compared with
the current limits on searching Dark Matter in the accelerator based
experiments. We demonstrate that the new approach can be effective tool to
probe sub-GeV Dark Matter parameter space.Comment: 8 pages,, 5 figures and 1 Tabl
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
TeV and by STAR at 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 MeV, while at STAR energy there is a
single freeze-out of hadrons and nuclei at the temperature
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
Study of Antibiotic Resistance of the Oropharyngeal Hemolytic Microflora in Preschool Children
It is impossible to imagine modern medical practice without antibiotic therapy. However, the rapid development of the pharmaceutical industry expands free access of the population to antibacterial drugs. At the same time, the illiteracy of people with respect to the principles of rational antibiotic therapy also increases. The problem of microbial resistance to antibacterial drugs remains relevant to this day. Special attention should be paid to rational antibiotic therapy applied to children.The purpose of this work was to study the resistance of hemolytic microorganisms, which are often the cause of upper respiratory infection in preschool children, to the main antibacterial drugs used in pediatric practice. The results of this scientific research can be advisory and useful to pediatricians and other specialists whose professional activities are related to childrenβs health.
Keywords: hemolytic active microorganisms, bacterial carriage, antibiotic resistance, childrenβs healt
ΠΠ΅Π³ΠΎΡΠ½Π°Ρ ΡΠ΅Π°Π±ΠΈΠ»ΠΈΡΠ°ΡΠΈΡ ΠΏΠ°ΡΠΈΠ΅Π½ΡΠΎΠ², ΠΏΠ΅ΡΠ΅Π½Π΅ΡΡΠΈΡ ΠΊΠΎΡΠΎΠ½Π°Π²ΠΈΡΡΡΠ½ΡΡ ΠΈΠ½ΡΠ΅ΠΊΡΠΈΡ COVID-19 (ΠΊΠ»ΠΈΠ½ΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΏΡΠΈΠΌΠ΅ΡΡ)
At the end of 2019, an outbreak of a new coronavirus infection was identified in the Peopleβs Republic of China centerd in the city of Wuhan. The official name COVID-19 (COronaVIrus Disease 2019) was assigned to the infection caused by the novel coronavirus by the World Health Organization on February 11, 2020. The International Committee on Taxonomy of Viruses assigned the name to the causative agent of the infection β SARS-CoV-2 on February 11, 2020. The bilateral pneumonia is currently known to be the most common clinical manifestation of the variant of coronavirus infection. The development of acute respiratory distress syndrome was found in 3 β 4% of patients. As a result of pneumonia, patients develop ventilation and perfusion disorders, weakness of skeletal muscles. To recover patients after viral pneumonia, methods of pulmonary rehabilitation should be applied. This article represents the methods of pulmonary rehabilitation aimed to improve the blood circulation in the lungs, the ventilation-perfusion ratios, and to the restoration of the skeletal muscles.Π ΠΊΠΎΠ½ΡΠ΅ 2019 Π³ΠΎΠ΄Π° Π² ΠΠΈΡΠ°ΠΉΡΠΊΠΎΠΉ ΠΠ°ΡΠΎΠ΄Π½ΠΎΠΉ Π Π΅ΡΠΏΡΠ±Π»ΠΈΠΊΠ΅ ΠΏΡΠΎΠΈΠ·ΠΎΡΠ»Π° Π²ΡΠΏΡΡΠΊΠ° Π½ΠΎΠ²ΠΎΠΉ ΠΊΠΎΡΠΎΠ½Π°Π²ΠΈΡΡΡΠ½ΠΎΠΉ ΠΈΠ½ΡΠ΅ΠΊΡΠΈΠΈ Ρ ΡΠΏΠΈΡΠ΅Π½ΡΡΠΎΠΌ Π² Π³ΠΎΡΠΎΠ΄Π΅ Π£Ρ
Π°Π½Ρ. ΠΡΠ΅ΠΌΠΈΡΠ½Π°Ρ ΠΎΡΠ³Π°Π½ΠΈΠ·Π°ΡΠΈΡ Π·Π΄ΡΠ°Π²ΠΎΠΎΡ
ΡΠ°Π½Π΅Π½ΠΈΡ 11.02.20 ΠΏΡΠΈΡΠ²ΠΎΠΈΠ»Π° ΠΎΡΠΈΡΠΈΠ°Π»ΡΠ½ΠΎΠ΅ Π½Π°Π·Π²Π°Π½ΠΈΠ΅ ΠΈΠ½ΡΠ΅ΠΊΡΠΈΠΈ, Π²ΡΠ·Π²Π°Π½Π½ΠΎΠΉ Π½ΠΎΠ²ΡΠΌ ΠΊΠΎΡΠΎΠ½Π°Π²ΠΈΡΡΡΠΎΠΌ, COVID-19 (CΠronaVIrus DiseaseΒ2019). ΠΠ΅ΠΆΠ΄ΡΠ½Π°ΡΠΎΠ΄Π½ΡΠΉ ΠΊΠΎΠΌΠΈΡΠ΅Ρ ΠΏΠΎ ΡΠ°ΠΊΡΠΎΠ½ΠΎΠΌΠΈΠΈ Π²ΠΈΡΡΡΠΎΠ² 11.02.20 ΠΏΡΠΈΡΠ²ΠΎΠΈΠ» Π½Π°Π·Π²Π°Π½ΠΈΠ΅ Π²ΠΎΠ·Π±ΡΠ΄ΠΈΡΠ΅Π»Ρ ΠΈΠ½ΡΠ΅ΠΊΡΠΈΠΈ SARS-CoV-2. Π Π½Π°ΡΡΠΎΡΡΠ΅Π΅ Π²ΡΠ΅ΠΌΡ ΠΈΠ·Π²Π΅ΡΡΠ½ΠΎ, ΡΡΠΎ Π½Π°ΠΈΠ±ΠΎΠ»Π΅Π΅ ΡΠ°ΡΠΏΡΠΎΡΡΡΠ°Π½Π΅Π½Π½ΡΠΌ ΠΊΠ»ΠΈΠ½ΠΈΡΠ΅ΡΠΊΠΈΠΌ ΠΏΡΠΎΡΠ²Π»Π΅Π½ΠΈΠ΅ΠΌ Π²Π°ΡΠΈΠ°Π½ΡΠ° ΠΊΠΎΡΠΎΠ½Π°Π²ΠΈΡΡΡΠ½ΠΎΠΉ ΠΈΠ½ΡΠ΅ΠΊΡΠΈΠΈ ΡΠ²Π»ΡΠ΅ΡΡΡ Π΄Π²ΡΡΡΠΎΡΠΎΠ½Π½ΡΡ ΠΏΠ½Π΅Π²ΠΌΠΎΠ½ΠΈΡ, Ρ 3β4 % ΠΏΠ°ΡΠΈΠ΅Π½ΡΠΎΠ² Π·Π°ΡΠ΅Π³ΠΈΡΡΡΠΈΡΠΎΠ²Π°Π½ΠΎ ΡΠ°Π·Π²ΠΈΡΠΈΠ΅ ΠΎΡΡΡΠΎΠ³ΠΎ ΡΠ΅ΡΠΏΠΈΡΠ°ΡΠΎΡΠ½ΠΎΠ³ΠΎ Π΄ΠΈΡΡΡΠ΅ΡΡΡΠΈΠ½Π΄ΡΠΎΠΌΠ°. ΠΡΠΈ ΠΏΠ½Π΅Π²ΠΌΠΎΠ½ΠΈΠΈ Ρ ΠΏΠ°ΡΠΈΠ΅Π½ΡΠΎΠ² ΡΠ°Π·Π²ΠΈΠ²Π°ΡΡΡΡ Π²Π΅Π½ΡΠΈΠ»ΡΡΠΈΠΎΠ½Π½ΠΎ-ΠΏΠ΅ΡΡΡΠ·ΠΈΠΎΠ½Π½ΡΠ΅ Π½Π°ΡΡΡΠ΅Π½ΠΈΡ, ΡΠ»Π°Π±ΠΎΡΡΡ ΡΠΊΠ΅Π»Π΅ΡΠ½ΠΎΠΉ ΠΌΡΡΠΊΡΠ»Π°ΡΡΡΡ. ΠΠ»Ρ Π²ΠΎΡΡΡΠ°Π½ΠΎΠ²Π»Π΅Π½ΠΈΡ ΠΏΠ°ΡΠΈΠ΅Π½ΡΠΎΠ² ΠΏΠΎΡΠ»Π΅ Π²ΠΈΡΡΡΠ½ΠΎΠΉ ΠΏΠ½Π΅Π²ΠΌΠΎΠ½ΠΈΠΈ Π½Π΅ΠΎΠ±Ρ
ΠΎΠ΄ΠΈΠΌΠ° Π»Π΅Π³ΠΎΡΠ½Π°Ρ ΡΠ΅Π°Π±ΠΈΠ»ΠΈΡΠ°ΡΠΈΡ. Π Π΄Π°Π½Π½ΠΎΠΉ ΡΡΠ°ΡΡΠ΅ ΠΏΡΠΈΠ²Π΅Π΄Π΅Π½Ρ ΠΌΠ΅ΡΠΎΠ΄Ρ Π»Π΅Π³ΠΎΡΠ½ΠΎΠΉ ΡΠ΅Π°Π±ΠΈΠ»ΠΈΡΠ°ΡΠΈΠΈ, Π½Π°ΠΏΡΠ°Π²Π»Π΅Π½Π½ΡΠ΅ Π½Π° ΡΠ»ΡΡΡΠ΅Π½ΠΈΠ΅ ΠΊΡΠΎΠ²ΠΎΠΎΠ±ΡΠ°ΡΠ΅Π½ΠΈΡ Π² Π»Π΅Π³ΠΊΠΈΡ
, Π²Π΅Π½ΡΠΈΠ»ΡΡΠΈΠΎΠ½Π½ΠΎ-ΠΏΠ΅ΡΡΡΠ·ΠΈΠΎΠ½Π½ΡΡ
ΠΎΡΠ½ΠΎΡΠ΅Π½ΠΈΠΉ, Π²ΠΎΡΡΡΠ°Π½ΠΎΠ²Π»Π΅Π½ΠΈΠ΅ ΡΠ°Π±ΠΎΡΡ ΡΠΊΠ΅Π»Π΅ΡΠ½ΠΎΠΉ ΠΌΡΡΠΊΡΠ»Π°ΡΡΡΡ
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