Observational constraints on the types of cosmic strings

This paper is aimed at setting observational limits to the number of cosmic strings (Nambu-Goto, Abelian-Higgs, semilocal) and other topological defects (textures). Radio maps of CMB anisotropy, provided by the space mission Planck for various frequencies, were filtered and then processed by the method of convolution with modified Haar functions (MHF) to search for cosmic string candidates. This method was designed to search for solitary strings, without additional assumptions about the presence of networks of such objects. The sensitivity of the MHF method is $\delta T \approx 10 \mu K$ in a background of $\delta T \approx 100 \mu K$. The comparison of these with previously known results on search string network shows that strings can only be semilocal in an amount of $1 \div 5$, with the upper restriction on individual strings tension (linear density) of $G\mu/c^2 \le 7.36 \cdot 10^{-7}$. The texture model is also legal. There are no strings with $G\mu/c^2 > 7.36 \cdot 10^{-7}$. However, comparison with the data for the search of non-Gaussian signals shows that the presence of several (up to 3) of Nambu-Goto strings is also possible. For $G\mu/c^2 \le 4.83 \cdot 10^{-7}$ the MHF method is ineffective because of unverifiable spurious string candidates. Thus the existence of strings with tensions $G\mu/c^2 \le 4.83 \cdot 10^{-7}$ is not prohibited but it is beyond the Planck data possibilities.Comment: 15 pages, 10 figures; accepted by the European Physical Journal

Residents’ Attitudes Towards Place Marketing: Tourism Marketing Focus

This article examines theoretical aspects of the co-production concept and illustrates its applicability within the framework of place marketing and tourism. A theoretical exploratory technique based on literature and discussion is employed to propose a conceptual model on residents’ willingness to be engaged in co-production activities.

The role of urban development in formation of countries' comparative advantages

Factors that increase the competitiveness of developed countries are very important aspects nowadays. The Nordic countries are increasing their competitiveness at the same time with the growth of the urban population. The paper analyzes the indirect impact of urbanization on countries’ comparative advantages and the consequences of this relationship for business

Entangled resource for interfacing single- and dual-rail optical qubits

Today's most widely used method of encoding quantum information in optical qubits is the dual-rail basis, often carried out through the polarisation of a single photon. On the other hand, many stationary carriers of quantum information - such as atoms - couple to light via the single-rail encoding in which the qubit is encoded in the number of photons. As such, interconversion between the two encodings is paramount in order to achieve cohesive quantum networks. In this paper, we demonstrate this by generating an entangled resource between the two encodings and using it to teleport a dual-rail qubit onto its single-rail counterpart. This work completes the set of tools necessary for the interconversion between the three primary encodings of the qubit in the optical field: single-rail, dual-rail and continuous-variable.Comment: Published in Quantu

Energy spectra of proton and nuclei of primary cosmic rays in energy region 10 TeV/particle

To investigate the chemical composition of primary cosmic rays, several emulsion chambers were exposed at a 10.8 g/sq cm. depth in the stratosphere. Each chamber has the area of 0.92x0.46 sq m. and the depth of 14 c.u. The exposure time of chambers processed by now is 260 hours. The detecting layers were X-ray films and nuclear emulsions, which allowed to measure an energy of cascade and a type of primary particle. Results and techniques are described