198 research outputs found
Conformal symmetry and light flavor baryon spectra
The degeneracy among parity pairs systematically observed in the N and Delta
spectra is interpreted to hint on a possible conformal symmetry realization in
the light flavor baryon sector in line with AdS_5/CFT_4. The case is made by
showing that all the observed N and Delta resonances with masses below 2500 MeV
distribute fairly well each over the first levels of a unitary representation
of the conformal group, a representation that covers the spectrum of a
quark-diquark system, placed directly on the AdS_5 cone, conformally
compactified to R^1*S^3. The free geodesic motion on the S^3 manifold is
described by means of the scalar conformal equation there, which is of the
Klein-Gordon type. The equation is then gauged by the "curved" Coulomb
potential that has the form of a cotangent function. Conformal symmetry is not
exact, this because the gauge potential slightly modifies the conformal
centrifugal barrier of the free geodesic motion. Thanks to this, the degeneracy
between P11-S11 pairs from same level is relaxed, while the remaining states
belonging to same level remain practically degenerate. The model describes the
correct mass ordering in the P11-S11 pairs through the nucleon spectrum as a
combined effect of the above conformal symmetry breaking, on the one side, and
a parity change of the diquark from a scalar at low masses, to a pseudoscalar
at higher masses, on the other. The quality of the wave functions is
illustrated by calculations of realistic mean-square charge radii and electric
charge form-factors on the examples of the proton, and the protonic P11(1440),
and S11(1535) resonances. The scheme also allows for a prediction of the
dressing function of an effective instantaneous gluon propagator from the
Fourier transform of the gauge potential. We find a dressing function that is
finite in the infrared and tends to zero at infinity.Comment: Latex, 5 figures, 2 tables; Paper upgraded in accord with the
published version. Discussion on the meson sector include
Trends and Vectors of Development of Information Educational Resources in the Context of Military Aggression
Under conditions of large-scale military aggression, Ukrainians had to mobilize and clearly respond to radical changes in all spheres of life. The education system updates and diversifies educational resources, disciplinary knowledge, and demonstrates readiness for all possible types of education: off-line (in regions without warfare), online (in red zones and in case of massive rocket attacks), hybrid education, individualized education (for refugees), etc. Education in war involves the use of a variety of information resources and technologies, in addition, involves research operations, selection, use, resulting in a powerful educational system response experience. In fact, in the past three years, humanity became a witness of significant changes in the information landscape available to education. Thus, it can be noted that all these reasons developed the proliferation of online learning and social platforms, the increasing complexity of information storage and sharing methods. Namely, it is the education that offers the deployment of private or free educational resources, or the generalization of content sharing platforms, community websites, or the personal blogs of teachers
Determination of Fenspiride Hydrochloride Residues on Pharmaceutical Manufacturing Equipment Surfaces by HPLC Method
The cleaning procedure must be validated, so special attention must be devoted to the methods used for determination of trace amounts of drugs. A rapid, sensitive, and specific reverse phase high-performance liquid chromatographic (HPLC) method was developed for the quantitative determination of fenspiride hydrochloride residues on pharmaceutical manufacturing equipment surfaces. The calibration curve was linear over a concentration range from 1.0 to 100.0 μg/ml with a correlation coefficient of 0.99994. The detection limit and quantitation limit were 0.41 μg/ml and 1.25 μg/ml, respectively. The developed method was validated with respect to specificity, linearity, limit of detection, accuracy and precision
Marketing activity in the context of the digital economy
Purpose: The presented article aims to identify and assess the prospects of construction companies' marketing activities in the digital economy. Design/Methodology/Approach: For the description of the construction companies'marketing activities prospects in the digital economy it is necessary: first, to determine the specifics of the construction companies marketing activities; second, to assess the trends in the digital economy development in relation to the construction product promotion; third, to determine the directions of construction marketing development. Findings: For the estimating of the construction companies'marketing activities prospects in the digital economy the basic principles of the choice of the construction product making by the target consumers have been identified, the analysis of the efforts of construction companies marketing activities and potential buyers in the digital space has been carried. The authors systematized the basic directions of the development of construction companies' marketing activities in the digital economy. Practical Implications: The research results may be implemented into managerial practices in order to improve and increase the efficiency of construction companies' marketing activities. Originality/Value: The main contribution of this study is the assessment of the basic trends of development of construction companies'marketing activities in the digital economy, on the basis of which specific events of marketing policy can be implemented.peer-reviewe
Scaling Analysis of Solving Algorithms for Canonical Problem of Dispatching in the Context of Dynamic Programming
The paper analyses computational model based on dynamic programming for platforms with multicore processors and heterogeneous architectures with FPGA. The models are applied for solving a canonical problem of dispatching where the computation time significantly depends on the problem scale factor. The parallel algorithms of NP-hard problem of dispatching are complicate and require intensive RAM data exchange. In order to reduce the computation time, it is suggested to use FPGA as a coprocessor providing massively parallel computation and increase the operational performance of the system in one order
Synthesis of Serving Policies for Objects Flow in the System with Refillable Storage Component
This paper discusses the solution of the logistic problem occurred in a management system to supply fuel to inhabitants in the Arctic regions using bulk water transport delivery. The suggested mathematical model of a logistic scheme is designed in the form of uniprocessor system with refillable storage component providing a single stage service of deterministic objects flow. The task scheduling optimisation problem is formulated in the way where service policies are estimated by two independent minimised criteria. Proposed synthesis algorithm of Pareto-efficient service policies utilises a bicriterial approach of dynamic programming. The algorithm has been verified by the simulation example
Boron-carbon coatings: structure, morphology and mechanical properties
Boron-doped carbon coatings have been produced by a method combining the deposition of a pulsed carbon plasma coating and a boron flow formed as a result of the evaporation of a boron target by pulsed YAG: Nd3+ laser irradiation. Phase, chemical composition, structure, and mechanical properties of composite boron-carbon coatings have been determined. Changes in the coatings’ roughness depending on the boron concentration have been established using atomic force microscopy. It has been shown that the grain size is on the rise with increasing boron concentration. Raman spectroscopy has revealed that at a boron concentration of 43.2 at. %. There is a sharp increase in the ID/IG ratio, which indicates the carbon component’s graphitization. Low ID/IG ratios are observed in the coating at low boron concentrations (no more than 17.4 at. %), suggesting a high content of carbon atoms with sp3 bond hybridization. The coating studies, carried out by X-ray photoelectron microscopy, showed that boron could be in a free state or in the form of carbide or oxide depending on the concentration in the coating. In this case, with an increase in boron concentration, there is a decrease in the concentration of carbon atoms in the state with sp3 bond hybridization, accompanied by an increase in the number of B-C bonds and a reduction in the boron concentration not associated with carbon and oxygen. These coating and chemical composition features determine the boron concentration’s established non-monotonic nature on their microhardness, elastic and mechanical properties
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