The characteristics of acoustic-gravity waves (waveforms, time durations, amplitudes, azimuths and horizontal phase speeds) from the eruption of the Hunga-Tonga-Hunga-Hapai volcano detected at ...different infrasound stations of the Infrasound Monitoring System and at a network of low-frequency microbarographs in the Moscow region are studied. Using the correlation analysis of the signals at different locations, six arrivals of signals from the volcano, which made up to two revolutions around the Earth, were detected. The Lamb mode of acoustic gravity waves from the volcano eruption is identified and the effect of this mode on generation of tsunami waves and variation of aerosol concentration is studied. The energy released from an underwater volcano into the atmosphere is estimated from the parameters of the Lamb wave and compared with the energy released from the most powerful nuclear bomb of 58 Mt TNT.
Data on internal gravity and infrasound waves recorded during the passage of both warm and cold fronts throughout Moscow, which are associated with the atmospheric storm of May 29, 2017, are given. ...These waves were recorded by four microbarographs located in the city of Moscow and Moscow region (and marked IFA, MGU, MSR, and ZNS in Fig. 1) and the data obtained were compared with data on infrasound waves recorded at the IS43 station in the town of Dubna. Time variations in the characteristics of internal gravity and infrasound waves (coherence, propagation azimuths, phase velocities, characteristic periods, and frequency spectra) during the passage of both warm and cold fronts are studied. The transition from the gravity to acoustic dispersive branch of acoustic-gravity waves due to increasing frequency and the temporal modulation of the phase velocity of infrasound waves due to internal gravity waves (IGWs) are also studied. Data on both aerosol (PM
10
) and gas (NO
2
) concentrations measured at different Moscow stations during the approaching atmospheric storm are given. The possibility of detecting wave precursors of atmospheric storms in simultaneous variations in atmospheric pressure, wind velocity, and pollutant concentrations is studied.
Short-lived ( τ ∼ 3 × 10 − 15 s ) π + K − , K + π − and π + π − atoms as well as long-lived ( τ ≥ 1 × 10 − 11 s) π + π − atoms produced in proton-nucleus interactions at 24 GeV c-1 are observed and ...studied in the DIRAC experiment at the CERN Proton Synchroton. The purpose of this paper is to show that the yields of the short-lived π + K − , K + π − and π + π − atoms in proton-nucleus interactions at 450 GeV c-1 and θ lab = 4 ° are estimated to be, respectively 67 13, 31 6 and 15 2 times higher. This may allow a significant improvement of the precision of their lifetime measurement and π π and π K scattering length combinations a 0 − a 2 and a 1 / 2 − a 3 / 2 . The yields of the long-lived π + K − , K + π − and π + π − atoms at 450 GeV c-1 are estimated to be 265 53, 120 24 and 60 9 times higher per time unit than at 24 GeV c-1. This may allow the resonance method to be used for measuring the Lamb shift in the π π atom and a new π π scattering length combination 2 a 0 + a 2 to be obtained.
The Drosophila MSL complex associates with active genes specifically on the male X chromosome to acetylate histone H4 at lysine 16 and increase expression approximately 2-fold. To date, no DNA ...sequence has been discovered to explain the specificity of MSL binding. We hypothesized that sequence-specific targeting occurs at “chromatin entry sites,” but the majority of sites are sequence independent. Here we characterize 150 potential entry sites by ChIP-chip and ChIP-seq and discover a GA-rich MSL recognition element (MRE). The motif is only slightly enriched on the X chromosome (∼2-fold), but this is doubled when considering its preferential location within or 3′ to active genes (>4-fold enrichment). When inserted on an autosome, a newly identified site can direct local MSL spreading to flanking active genes. These results provide strong evidence for both sequence-dependent and -independent steps in MSL targeting of dosage compensation to the male X chromosome.
The effect of the shape and size of silver nanoparticles on the electrochemical characteristics of sensors based on them is considered by the example of the hydrogen peroxide (H2O2) determination. A ...sodium-borohydride-based electrochemical sensor yields a one-fold increase in the analytical signal when H2O2 in a concentration of 1 × 10‒7 M is added. A sensor based on the finest (0.5–17.5 nm) spherical silver nanoparticles obtained using two reducing agents (sodium borohydride and sodium citrate) simultaneously makes it possible to increase the H2O2-determination sensitivity by six orders of magnitude (the detection limit is 0.16 × 10–13 M). The detectable H2O2-concentration range varies within half an order of magnitude and is (0.8‒3.0) × 10‒13 M. A sensor based on silver nanoparticles of various shapes 10‒55 nm in size obtained using sodium citrate also exhibits an increase in the H2O2-determination sensitivity by six orders of magnitude (the detection limit is 0.74 × 10–13 M). This sensor has a detectable H2O2 concentration range within an order of magnitude: (1.0‒10.0) × 10‒13 M. The causes of the different sensitivities and detectable H2O2-concentration ranges for the electrochemical sensors are discussed depending on the size and shape of silver nanoparticles. The mechanism of the interaction of adsorbed oxygen with silver nanoparticles on the sensor surface is proposed.
We present new constraints on sub-GeV dark-matter particles scattering off electrons based on 6780.0 kg d of data collected with the DarkSide-50 dual-phase argon time projection chamber. This ...analysis uses electroluminescence signals due to ionized electrons extracted from the liquid argon target. The detector has a very high trigger probability for these signals, allowing for an analysis threshold of three extracted electrons, or approximately 0.05 keVee. We calculate the expected recoil spectra for dark matter-electron scattering in argon and, under the assumption of momentum-independent scattering, improve upon existing limits from XENON10 for dark-matter particles with masses between 30 and 100 MeV/c^{2}.
The DarkSide-50 direct-detection dark matter experiment is a dual-phase argon time projection chamber operating at Laboratori Nazionali del Gran Sasso. This paper reports on the blind analysis of a ...(16 660±270) kg d exposure using a target of low-radioactivity argon extracted from underground sources. We find no events in the dark matter selection box and set a 90% C.L. upper limit on the dark matter–nucleon spin-independent cross section of 1.14×10−44 cm2 (3.78×10−44 cm2, 3.43×10−43 cm2) for a WIMP mass of 100 GeV/c2 (1 TeV/c2, 10 TeV/c2).
Chagas disease, caused by Trypanosoma cruzi, is a major neglected tropical disease affecting the Americas. The epidemiology of this disease in the United States is incomplete. We report evidence of ...likely autochthonous vectorborne transmission of T. cruzi and health outcomes in T. cruzi-seropositive blood donors in south central Texas, USA.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The stepwise mechanism of electrooxidation and reduction of silver nanophases and microphases is proposed on the graphite electrodes surface in alkaline medium. The electrochemical splitting of ...silver nanophases peak is observed on the anodic branch of the cyclic current-voltage curve. There is the shoulder at E = 0.2 V on the he anodic branch of cyclic current-voltage curve. The appearance of additional cathodic wave at E = -0.08 V is observed on the cathodic branch of the cyclic current-voltage curve that is caused by the reduction of silver nanoparticles. The additional cathode maximum is represented at 0.3 V on the cathodic branch of the cylic current-voltage curves of only silver nanophases. This effect is associated the catalytic process of decomposition of hydrogen peroxide on silver nanoparticles surface. The offset of the cathodic maxima of current-voltage curves of silver nanophases obtained with an excess of a reducing agent are observed to more negative potentials. There is a significant decrease of the all currents maxima compared to silver nanophases obtained with an equal molar ratio of reactants. These results may be connected with the formation of silver oxide monolayers in the different oxidation in the presence of large amounts a reducing agent. The excess of the reducing agent required for the preparation of silver nanoparticles leads to decrease of the cathodic maximum of silver nanoparticles
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