Tomographic images of Avacha and Koryaksky volcanoes in Kamchatka

2020 ◽  
Author(s):  
Natalia Bushenkova ◽  
Ivan Koulakov ◽  
Sergey Senyukov ◽  
Evgeny I. Gordeev ◽  
Hsin-Hua Huang ◽  
...  
Keyword(s):  
3D Structure ◽  
Thick Layer ◽  
Potential Hazard ◽  
Tomographic Images ◽  
Arrival Times ◽  
S Waves ◽  
Partial Melt ◽  
Magma Reservoirs ◽  
Upper Limit ◽  
First Time

<p>In this study, we have mapped for the first time robustly the 3D structure of two upper-crustal magmatic reservoirs beneath the active volcanoes Avacha and Koryaksky, which are called “home volcanoes” for Petropavlovsk-Kamchatsky, the main city of Kamchatka (~200,000 inhabitants). These volcanoes represent a serious potential hazard for the city, because they are located at a distance of 25–30 km from the populated areas. A new tomographic model (V<sub>P</sub>, V<sub>S</sub>, V<sub>P</sub>/V<sub>S</sub> ratio) was built, for which we used the arrival times of seismic P- and S-waves from almost 5,000 local events, recorded by a permanent network of seismic stations during 2009–2018.The resolution of the derived models was carefully tested by a series of synthetic simulations. Prominent anomalies with extremely high V<sub>P</sub>/V<sub>S</sub> ratios (up to 2.4) were retrieved directly beneath both volcanoes and interpreted as magma reservoirs containing high degrees of partial melt and/or fluids. Beneath Avacha, the upper limit of the anomaly is located at the depth of ~2 km below the surface. The reservoir appears to be connected to the surface by a neck-shaped anomaly of high V<sub>P</sub>/V<sub>S</sub> ratio associated with active seismicity, which is interpreted as a magma and fluid conduit. Beneath Koryaksky, the magma related anomaly is deeper: its upper limit is located at a depth of ~ 7 km below the surface. This anomaly is connected with the volcanic coneby a vertical seismicity cluster, which possibly marks the pathway of fluid ascent and degassing. Between the volcanoes, a 2–3 km thick layer of very low V<sub>P</sub> and V<sub>S</sub> is interpreted as deposits of volcanoclastic sediments. Generally low Vp/Vs ratios in the area between the volcanoes show that the magma reservoirs in the upper crust are not interconnected.</p><p>This study was partially supported by the RFBR project # 18-55-52003.</p>

scholarly journals Modeling and Molecular Dynamics of the 3D Structure of the HPV16 E7 Protein and Its Variants

2021 ◽  
Vol 22 (3) ◽  
pp. 1400
Author(s):  
Ciresthel Bello-Rios ◽  
Sarita Montaño ◽  
Olga Lilia Garibay-Cerdenares ◽  
Lilian Esmeralda Araujo-Arcos ◽  
Marco Antonio Leyva-Vázquez ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
3D Structure ◽  
Epidemiological Studies ◽  
Dynamics Simulation ◽  
Structural Refinement ◽  
Oncogenic Potential ◽  
Structural Differences ◽  
Reference Protein ◽  
E6 And E7 ◽  
First Time

The oncogenic potential of high-risk human papillomavirus (HPV) is predicated on the production of the E6 and E7 oncoproteins, which are responsible for disrupting the control of the cell cycle. Epidemiological studies have proposed that the presence of the N29S and H51N variants of the HPV16 E7 protein is significantly associated with cervical cancer. It has been suggested that changes in the amino acid sequence of E7 variants may affect the oncoprotein 3D structure; however, this remains uncertain. An analysis of the structural differences of the HPV16 E7 protein and its variants (N29S and H51N) was performed through homology modeling and structural refinement by molecular dynamics simulation. We propose, for the first time, a 3D structure of the E7 reference protein and two of Its variants (N29S and H51N), and conclude that the mutations induced by the variants in N29S and H51N have a significant influence on the 3D structure of the E7 protein of HPV16, which could be related to the oncogenic capacity of this protein.

scholarly journals Seismic detection of transient changes beneath Black Rapids Glacier, Alaska, U.S.A.: II. Basal morphology and processes

1999 ◽  
Vol 45 (149) ◽  
pp. 132-146 ◽  
Author(s):  
Matt Nolan ◽  
Keith Echelmeyer
Keyword(s):  
Hydraulic System ◽  
Seismic Analysis ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Basal Layer ◽  
Thick Layer ◽  
Reflection Coefficients ◽  
Overburden Pressure ◽  
Arrival Times ◽  
Black Rapids Glacier

AbstractUsing changes observed in daily seismic reflections, we have investigated the basal morphology of Black Rapids Glacier, Alaska, U.S.A. The englacial drainage of ice-marginal lakes caused significant changes in the daily reflections, as well as dramatic increases in basal motion. Changes in reflection arrival times and amplitudes indicate that there is a basal till layer at least 5 m thick at some locations beneath this surge-type glacier. Rapid changes in the observed reflection coefficients during the drainage events indicate that changes in till properties must occur throughout the entire 5 m thick layer, they must last for several days following the lake drainages and they must be completely reversible over as little as 36 min. Our seismic analysis shows that changes in effective pressure of the till are unlikely to cause the required changes in the reflection coefficients, but that a decrease in till saturation is likely. We therefore interpret the cause of the seismic anomalies as being a temporary decrease in saturation as water is input to the subglacial hydraulic system, and propose that such a change may occur quickly and reversibly by a redistribution of overburden pressure. Higher water pressures within the hydraulic system cause that region to support more of the glacier’s weight, leaving the remaining areas to support less. Any till within these areas of decreased normal stress would experience a consequent decrease in pore-water pressure, causing gas to exolve, thus decreasing saturation. This decrease in saturation would cause a change in the strength of the basal layer and may affect basal dynamics.

scholarly journals Preloading Effect On The Strength of Cement Mass Mixing Treated Salty Sand

2021 ◽  
Author(s):  
Rasoul Alipour
Keyword(s):  
Thick Layer ◽  
Test Results ◽  
Cement Slurry ◽  
Sem Images ◽  
Treated Soil ◽  
Pure Salt ◽  
Ucs Test ◽  
Southwest Of Iran ◽  
First Time ◽  
Electronic Microscope

Abstract Existing problematic sub-layers in mixing technologies are a challenge, and for the first time, the effects of salt sub-layers in mass mixing technology have been investigated in this study for sandy salt in the southwest of Iran. This paper discusses the influence of adding various cement contents, Aw, and imposing different preloading values on the salty sand soil. First, salt and sand samples were dried, then, 90 % sand was mixed with 10% salt. After that, 30 % water was mixed thoroughly with the mixture of salty sand to obtain slurries. Cement slurry at a water-cement ratio (w/c) of 0.6 was then added to the sample and thoroughly mixed. The amount of cement in a slurry form that was added to the salty soil was 2, 4, 6, 8, and 10% by mass of dry soil. Each treated soil preloaded by 0, 9, and 45 kPa. After 120 days, the unconfined compressive strength of the sample was determined. Furthermore, by Scanning Electronic Microscope, SEM, the microstructures of treated samples were analyzed. At the end Unconfined Compression Strength, UCS, test results normalized to the non-preloaded treated soil. By increasing cement content, the effect of preloading in increasing UCS will decrease. In the SEM images for Aw=2%, the effect of preloading indicates porous shape for non-preloaded samples. Vice versa by Aw=8%, porous shape in the SEM images will disappear. In the end, treatability studies of pure salt in the thick layer have been investigated.

scholarly journals Dynamic Range Analysis of the Phase Generated Carrier Demodulation Technique

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
M. J. Plotnikov ◽  
A. V. Kulikov ◽  
V. E. Strigalev ◽  
I. K. Meshkovsky
Keyword(s):  
Theoretical Analysis ◽  
Dynamic Range ◽  
Range Analysis ◽  
Upper Limit ◽  
Low Pass ◽  
Nonlinear Character ◽  
Simulation Results ◽  
Low Pass Filters ◽  
First Time ◽  
Phase Generated Carrier

The dependence of the dynamic range of the phase generated carrier (PGC) technique on low-pass filters passbands is investigated using a simulation model. A nonlinear character of this dependence, which could lead to dynamic range limitations or measurement uncertainty, is presented for the first time. A detailed theoretical analysis is provided to verify the simulation results and these results are consistent with performed calculations. The method for the calculation of low-pass filters passbands according to the required dynamic range upper limit is proposed.

scholarly journals “What’s the Robo-Driver up to?” Requirements for Screen-based Awareness and Intent Communication in Autonomous Buses

i-com ◽  
2019 ◽  
Vol 18 (2) ◽  
pp. 151-165 ◽  
Author(s):  
Peter Fröhlich ◽  
Raimund Schatz ◽  
Markus Buchta ◽  
Johann Schrammel ◽  
Stefan Suette ◽  
...  
Keyword(s):  
Augmented Reality ◽  
Visual Communication ◽  
State Of The Art ◽  
User Studies ◽  
Potential Hazard ◽  
The Road ◽  
On The Road ◽  
Study Participants ◽  
First Time ◽  
Public Demonstration

Abstract Autonomous buses are expected to become a cornerstone of future mobility systems. Especially during their introduction, passengers may require reassurance about the vehicle’s awareness of the situation on the road and of its intended next actions to further acceptance. In order to investigate the need and requirements for information about the vehicle’s awareness and intent from the perspective of first-time users, we conducted two user studies in a state-of-the-art autonomous bus at public demonstration spaces. In the first study, participants underwent a demonstration ride with the bus and were then asked about their needs for awareness and intent communication. The second study took participants on a ‘simulated ride’ within a stationary bus, in which typical scenarios of the road ahead were presented, together with different awareness and intent cues. Our results suggest that, first, future autonomous bus passengers may be in need of such awareness and intent communication screens. Second, we found that awareness and intent communication may be of greater importance for the indication of potential hazard recognition than for indicating route directions. Third, due to their complementary strengths, none of the three compared types of visual communication (text, icon and augmented reality) should be used in isolation.

scholarly journals Rindera graeca (Boraginaceae) Phytochemical Profile and Biological Activities

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3625
Author(s):  
Christos Ganos ◽  
Nektarios Aligiannis ◽  
Ioanna Chinou ◽  
Nikolaos Naziris ◽  
Maria Chountoulesi ◽  
...  
Keyword(s):  
Free Radical ◽  
Biological Activities ◽  
Biological Membrane ◽  
3D Structure ◽  
Total Phenolic ◽  
Phytochemical Analysis ◽  
Endemic Plant ◽  
Aerial Parts ◽  
Potential Applications ◽  
First Time

Rindera graeca is a Greek endemic plant of the Boraginaceae family which has never been studied before. Consequently, this study attempted to phytochemically examine the aerial parts of this species. Nine phenolic secondary metabolites were identified, consisting of seven caffeic acid derivatives and two flavonol glucosides, namely rutin and quercetin-3-rutinoside-7-rhamnoside. These flavonoids, together with rosmarinic acid, were isolated via column chromatography and structurally determined through spectral analysis. Quercetin-3-rutinoside-7-rhamnoside is an unusual triglycoside, which is identified for the first time in Rindera genus and among Boraginaceae plants. This metabolite was further examined with thermal analysis and its 3D structure was simulated, revealing some intriguing information on its interaction with biological membrane models, which might have potential applications in microcirculation-related conditions. R. graeca was also analyzed for its pyrrolizidine alkaloids content, and it was found to contain echinatine together with echinatine N-oxide and rinderine N-oxide. Additionally, the total phenolic and flavonoid contents of R. graeca methanol extract were determined, along with free radical inhibition assays. High total phenolic content and almost complete inhibition at experimental doses at the free radical assays indicate a potent antioxidant profile for this plant. Overall, through phytochemical analysis and biological activity assays, insight was gained on an endemic Greek species of the little-studied Rindera genus, while its potential for further applications has been assessed.

Growth of Cubic Silicon Carbide on Silicon Using Hot Filament CVD

2017 ◽  
Vol 897 ◽  
pp. 91-94
Author(s):  
Philip Hens ◽  
Ryan Brow ◽  
Hannah Robinson ◽  
Michael Cromar ◽  
Bart van Zeghbroeck
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Degrees Of Freedom ◽  
Thick Layer ◽  
Chemical Vapor ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Hot Filament ◽  
Cubic Silicon Carbide ◽  
First Time

In this paper, we report, for the first time, growth of high-quality single-crystalline 3C-SiC on silicon substrates using Hot Filament Chemical Vapor Deposition (HF-CVD). Rocking curve X-Ray diffraction (XRD) measurements revealed a full-width at half maximum (FWHM) as low as 333 arcsec for a 15 μm thick layer. Low tensile strain, below 0.1%, was measured using Raman spectroscopy. This quality was achieved with a carefully optimized process making use of the additional degrees of freedom the hot filaments create. For example, the hot filaments allow for precursor pre-cracking. Additionally, they allow a tuning of the vertical thermal gradient which creates an improved thermal field compared to classic Chemical Vapor Deposition techniques used for the deposition of this material today.

scholarly journals Long term Arecibo monitoring of the water megamaser in MG J0414+0534

2012 ◽  
Vol 8 (S287) ◽  
pp. 340-344
Author(s):  
Paola Castangia ◽  
C. M. Violette Impellizzeri ◽  
John P. McKean ◽  
Christian Henkel ◽  
Andreas Brunthaler ◽  
...  
Keyword(s):  
High Redshift ◽  
Main Peak ◽  
Powerful Radio ◽  
Upper Limit ◽  
Maser Line ◽  
Line Widths ◽  
Velocity Drift ◽  
First Time ◽  
Water Maser

AbstractWe monitored the 22 GHz maser line in the lensed quasar MG J0414+0534 at z = 2.64 with the 300-m Arecibo telescope for almost two years to detect possible additional maser components and to measure a potential velocity drift of the lines. The main maser line profile is complex and can be resolved into a number of broad features with line widths of 30-160 km s−1. A new maser component was tentatively detected in October 2008 at a velocity of +470 km s−1. After correcting for the estimated lens magnification, we find that the H2O isotropic luminosity of the maser in MG J0414+0534 is ~26,000 solar luminosities, making this source the most luminous ever discovered. Both the main line peak and continuum flux densities are surprisingly stable throughout the period of the observations. An upper limit on the velocity drift of the main peak of the line has been estimated from our observations and is of the order of 2 km s−1 per year. We discuss the results of the monitoring in terms of the possible nature of the maser emission, associated with an accretion disk or a radio jet. This is the first time that such a study is performed in a water maser source at high redshift, potentially allowing us to study the parsec-scale environment around a powerful radio source at cosmological distances.

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