Two-path succussive relaying with hybrid demodulate and forward

This paper proposes a novel demodulation-and-forward (DMF) scheme for the two-path succussive relay system. While the two-path relaying avoids the data rate loss that occurs in many one-relay cooperative systems, its performance is severely limited by interrelay interference. In this paper, we propose a hybrid DMF scheme for the two-path relay system so that the relays can switch between direct and differential demodulation modes according to channel conditions. The hybrid DMF scheme not only performs better than existing two-path approaches but is easy to achieve synchronization at the relays as well, which is particularly important as a relay receives signals from both the source and the other relay. The proposed hybrid DMF scheme provides an innovative way to implement the two-path relaying scheme

Графический дизайн как визуальный язык межкультурного взаимодействия

This article describes how visual graphics language as a sign system can be in contact with the audience, overcoming the language barrier. In terms of graphic design it can be available to transfer information, and even affect the viewer, causing artistic and emotional reflection.Эта статья о том, как визуальный язык графики в виде знаковой символики может входить в контакт со зрителем, преодолевая языковый барьер. На языке графического дизайна можно доступно передать информацию и даже воздействовать на зрителя, вызывая при этом художественно-эмоциональные образы

Ab Initio Calculation of the Heats of Formation of Nitrosamides: Comparison with Nitramides

Ab initio calculations of the structures and energies of the mono-, di-, and trinitrosamides are compared to mono-, di-, and trinitramides. Highly accurate standard heats of formation of this series of nitramides and nitrosamides are calculated using isodesmic reactions and high-level theories. The nitrosamides have heats of formation at 0 K that are 20−40 kcal/mol higher than the analogous nitramides. The N−N bond strengths are comparable whether a NO or NO2 group is bonded to the central nitrogen atom. The data suggest that converting the nitro groups to nitroso groups will result in compounds that have lower weight, shorter N−N bond lengths, and higher energy content, at the expense of lower oxygen balance. This suggests that nitrosamides are potentially useful high-energy materials. A revised ΔHf° for NH2NO2 is proposed to be 3.8 kcal/mol at 0 K, in close agreement with previous theory and very different from experiment. Recommended values for ΔHf° are 34 and 71 kcal/mol for di- and trinitramide, respectively, and 22, 65, and 112 kcal/mol for mono-, di- and trinitrosamide, respectively. The errors in the monosubstituted molecules are estimated at 1 kcal/mol, and the errors are estimated at ±2 and ±3 kcal/mol for the di- and trisubstituted molecules, respectively. Nitrosamides have bond strengths comparable to those of the nitramides

<i>Ab Initio</i> Study of Pernitric Acid: Comparison with Experimental Spectra

A high-level ab initio theoretical study has been performed on the spectra and bond energies of pernitric acid, HO2NO2. Excellent agreement with experimental rotational constants, 15N NMR chemical shifts, HO2 + NO2 reaction enthalpy, and vibrational frequencies are obtained. Slight revisions of low-frequency normal modes have been made. Vertical excitations are computed by CASPT2 for comparison with future high-resolution UV−visible spectra and match the low resolution UV−visible spectra of pernitric acid in solution. The optimized geometries reported are superior to previous microwave structures because assumptions of bond lengths and angles from the analogous nitric acid and hydrogen peroxide molecules introduce significant errors

Preoperative, intraoperative and postoperative data of patients.

<p>CAG = conventional antegrade MAG = modified antegrade.</p

Asymmetric [4 + 3] Annulations for Constructing Divergent Oxepane Frameworks via Cooperative Tertiary Amine/Transition Metal Catalysis

We report asymmetric [4 + 3] annulations between isatin-derived Morita–Baylis–Hillman carbonates and two types of vinyl carbonates synergistically catalyzed by tertiary amines and transition metals, through chemoselective assemblies of in situ formed allylic ylides and metal-containing 1,4-dipoles. A range of oxepane frameworks are generally constructed in moderate to good yields with high stereocontrol. Moreover, all four diastereomers for the products bearing vicinal stereocenters are accessible by tuning tertiary amine and metal catalysts

Additional file 1 of The putative mechanistic insights on how SARS-CoV-2 might influence the outcomes in cancer patients

Additional file 1. Detailed information for materials, methods and results

Air quality modeling for effective environmental management in the mining region

<p>Air quality in the mining sector is a serious environmental concern and associated with many health issues. Air quality management in mining regions has been facing many challenges due to lack of understanding of atmospheric factors and physical removal mechanisms. A modeling approach called the mining air dispersion model (MADM) is developed to predict air pollutants concentration in the mining region while considering the deposition effect. The model takes into account the planet’s boundary conditions and assumes that the eddy diffusivity depends on the downwind distance. The developed MADM is applied to a mining site in Canada. The model provides values for the predicted concentrations of PM₁₀, PM_2.5, TSP, NO₂, and six heavy metals (As, Pb, Hg, Cd, Zn, Cr) at various receptor locations. The model shows that neutral stability conditions are dominant for the study site. The maximum mixing height is achieved (1280 m) during the evening in summer, and the minimum mixing height (380 m) is attained during the evening in winter. The dust fall (PM coarse) deposition flux is maximum during February and March with a deposition velocity of 4.67 cm/sec. The results are evaluated with the monitoring field values, revealing a good agreement for the target air pollutants with <i>R</i>-squared ranging from 0.72 to 0.96 for PM_2.5, from 0.71 to 0.82 for PM₁₀, and from 0.71 to 0.89 for NO₂. The analyses illustrate that the presented algorithm in this model can be used to assess air quality for the mining site in a systematic way. Comparisons of MADM and CALPUFF modeling values are made for four different pollutants (PM_2.5, PM₁₀, TSP, and NO₂) under three different atmospheric stability classes (stable, neutral, and unstable). Further, MADM results are statistically tested against CALPUFF for the air pollutants and model performance is found satisfactory.</p> <p><i>Implications</i>: The mathematical model (MADM) is developed by extending the Gaussian equation particularly when examining the settling process of important pollutants for the industrial region. Physical removal effects of air pollutants with field data have been considerred for the MADM development and for an extensive field case study. The model is well validated in the field of an open pit mine to assess the regional air quality. The MADA model helps to facilitate the management of the mining industry in doing estimation of emission rate around mining activities and predicting the resulted concentration of air pollutants together in one integrated approach.</p

Dynamically Coupled 3D Pollutant Dispersion Model for Assessing Produced Water Discharges in the Canadian Offshore Area

Produced water is the contaminated water that is brought to the surface in the process of recovering oil and gas. On the basis of discharge volume, this type of contaminated water is the largest contributor to the offshore waste stream. Modeling studies of large amounts of wastewater discharge into offshore areas have helped in the understanding of pollutant dispersion behaviors in marine environments and in further evaluating the potential environmental effects resulting from produced water discharges. This study presents an integrated three-dimensional (3D) approach for the simulation of produced water discharges in offshore areas. Specifically, an explicit second-order finite difference method was used to model the far-field pollutant dispersion behavior, and this method was coupled with the jet-plume model JETLAG with an extension of the 3D cross-flow conditions to simulate the near-field mixing processes. A dynamic coupling technique with full consideration of the interaction between the discharged fluids and receiving waters was employed in the model. A case study was conducted on the Grand Banks of Newfoundland, Canada. The field validation of the modeling results was conducted for both the near-field and far-field dispersion processes, and the modeling results were in good agreement with the field observations. This study provides an integrated system tool for the simulation of complex transport processes in offshore areas, and the results from such modeling systems can be further used for the risk assessment analysis of the surface water environment

Boron Coprecipitation with Calcite: Distinguishing Calcite-Hosted B by NMR Spectroscopy

The boron isotope composition for boron incorporated in marine calcium carbonate minerals has become an increasingly important proxy for seawater pH and thus a key constraint for the concentration of atmospheric carbon dioxide in the geologic past. We report here the results of a solid-state NMR study undertaken to investigate the nature of the boron substitution in calcite and its relationship to the calcite structure. Calcite/boron coprecipitates with B concentrations ranging from 149 to 1260 μg/g were prepared using the constant rate of addition method with 99% 13C-carbonate to facilitate the application of double-resonance NMR techniques. The 11B MAS/NMR spectra indicate the presence of both three-coordinated (B(3)) and four-coordinated boron (B(4)) in all of the synthetic samples, with subequal abundances. Strong dephasing effects were observed in 11B-observed/13C rotational-echo double-resonance (REDOR) experiments for both B(3) and B(4), indicating that both types of coordination environment occur in the calcite structure and in atomically close proximity to carbonate groups. The variation in the REDOR spectra with dephasing time for the sample with the highest B content reveals the presence of two distinct trigonal B environments that differ principally in the quadrupolar asymmetry parameter (η). Only the asymmetric B(3) (η ≅ 0.65) occurs in the REDOR difference spectra and can be assigned to calcite-hosted boron. The signal from an axially symmetric trigonal environment (η ≅ 0) dominates the dephased REDOR spectra at intermediate dephasing times and exhibits rapid spin–spin relaxation, suggesting assignment to B[OH]3 groups external to calcite. The symmetric B(3) accounts for ∼15% of the B for samples with the highest B content but appears to be much less abundant or absent in samples with a lower B content, including modern and fossil brachiopods. Model-free decomposition of the 11B spin–echo spectra corroborates this interpretation of the REDOR results. Comparison of the NMR parameters calculated in a previous study with those measured for B(4) and the asymmetric B(3) indicates assignment, respectively, to B[OH]4– and BO2[OH]2– groups in calcite. These results are consistent with the incorporation of trigonal B in calcite during coprecipitation but inconclusive as to whether it results from deprotonation of boric acid or coordination change of the borate ion through deprotonation and hydroxyl transfer reactions. In either case, incorporation of trigonal B must involve multiple hydrolytic processes at the calcite/fluid interface during crystal growth, which converge to yield a surprisingly structurally homogeneous B(3) substitution