Twisted bilayer graphene is an excellent example of highly correlated system demonstrating a nearly flat electron band, the Mott transition and probably a spin liquid state. Besides the one-electron ...picture, analysis of Dirac points is performed in terms of spinon Fermi surface in the limit of strong correlations. Application of gauge field theory to describe deconfined spin liquid phase is treated. Topological quantum transitions, including those from small to large Fermi surface in the presence of van Hove singularities, are discussed.
It was shown by (Nakamura et al. 1997), (Ioka et al. 1998), and (Sasaki et al. 2016) that primordial black holes (PBHs) binaries can form effectively at the cosmological stage of radiation dominance, ...and the merge of the PBHs in pairs can explain the gravitational wave burst GW150914. In this paper, the model is re-examined by considering the effect of inflationary dark matter density perturbations which produce additional tidal forces. As a result, the merge rate of PBHs binaries and the corresponding rate of the gravitational bursts can be suppressed by the factor ≈ 1.5 − 2 in comparison with previous calculations. This rate matches the LIGO data if the PBHs constitute the f ≈ 5 × 10-4 − 5 × 10-3 fraction of dark matter.
The work studied the influence of plant growth regulators as well as the effect of monochromatic radiation of different spectral composition on the growth and accumulation of secondary metabolites in ...the callus culture of sweet potato (
Ipomoea batatas
L.). It was found that auxin analogues in low concentrations (0.5 mg/L) significantly stimulated the growth of cell biomass, while the effect of 4-chlorophenoxyacetic acid (4-CPA) was more pronounced (stimulation 16 times) than that of 2,4-dichlorophenoxyacetic acid (2,4-D) (13.5 times stimulation). Both the increase in the concentration of 2,4-D and 4-CPA in the medium and the addition of cytokinin, 6-benzylaminopurine (BAP), led to a significant inhibition of culture growth (up to three times). In contrast to 2,4-D, the addition of 4-CPA led to an eightfold increase in the total content of polyphenolic compounds in cultured cells. Activating effect of 4-CPA on the biosynthetic characteristics of
I. batatas
cell culture persisted even with the addition of BAP, while an increase in the concentration of 4‑CPA led to the leveling of the activating effect. Monochromatic radiation—white, red (660 and 630 nm), yellow, green, and blue (440 and 460 nm) light—inhibited growth (up to 1.5 times) and the total accumulation of secondary metabolites in
I. batatas
cells (up to 1.8 times). At the same time, the white, bright blue, and red spectra differentially activated the formation of individual compounds 3,4-dicaffeoylquinic acid and 3-feruloyl-5-caffeoylquinic acid. Thus, the authors have established that both auxin analogues and spectral radiation exhibit different effects on the growth and biosynthetic characteristics of the
I. batatas
calli.
Sentiment analysis (SA) has become one of the most active and progressively popular areas in information retrieval and text mining due to the expansion of the World Wide Web (WWW). SA deals with the ...computational treatment or the classification of user’s sentiments, opinions and emotions hidden within the text. Aspect extraction is the most vital and extensively explored phase of SA to carry out the classification of sentiments in precise manners. During the last decade, enormous number of research has focused on identifying and extracting aspects. Therefore, in this survey, a comprehensive overview has been attempted for different aspect extraction techniques and approaches. These techniques have been categorized in accordance with the adopted approach. Despite being a traditional survey, a comprehensive comparative analysis is conducted among different approaches of aspect extraction, which not only elaborates the performance of any technique but also guides the reader to compare the accuracy with other state-of-the-art and most recent approaches.
Sulfation of larch wood arabinogalactan (AG) with sulfamic acid in dimethylsulfoxide (DMSO) medium in the presence of urea was studied for the first time. The use of DMSO as a solvent instead of more ...toxic 1,4-dioxane allows to sulfate AG under homogeneous conditions. The sulfated AG with a high sulfur content (12.0–12.5 wt %) was produced by sulfation at a temperature of 85–90 °C, the molar ratio of AG / sulfating agent equal to 1:0.85 during 2–3 h. The introduction of sulfate groups into the structure of arabinogalactan was confirmed by the appearance of new absorption bands in FTIR and FT Raman spectra, characteristic for the vibrations of the sulfate groups. It was proved by
13
C NMR spectroscopy that the predominant substitution of the primary hydroxyl groups at C6 carbon atoms of the terminal galactose units of main and side chains of arabinogalactan takes place. Simultaneously, the hydroxyl groups associated with C2 and C4 carbon atoms of galactose unit of the main chain are only partially sulfated. According to results of GPC study, the sulfated AG is characterized by a narrow molecular weight distribution with an average molecular weight of 18.8 kDa and a polydispersity of 1.3.
A
bstract
In this paper we study the SU(3)-gluodynamics shear viscosity temperature dependence on the lattice. To do so, we measure the correlation functions of the energy-momentum tensor in the ...range of temperatures
T /T
c
∈ 0
.
9
,
1
.
5. To extract the shear viscosity we used two approaches. The first one is to fit the lattice data with a physically motivated ansatz for the spectral function with unknown parameters and then determine the shear viscosity. The second approach is to apply the Backus-Gilbert method allowing to extract the shear viscosity from the lattice data nonparametrically. The results obtained within both approaches agree with each other. Our results allow us to conclude that within the range
T /T
c
∈ 0
.
9
,
1
.
5 the SU(3)-gluodynamics reveals the properties of a strongly interacting system, which cannot be described perturbatively, and has the ratio
η/s
close to the value 1
/
4
π
of the
N
= 4 Supersymmetric Yang-Mills theory.
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