Oscillatory Behavior of Critical Amplitudes of the Gaussian Model on a Hierarchical Structure

We studied oscillatory behavior of critical amplitudes for the Gaussian model on a hierarchical structure presented by a modified Sierpinski gasket lattice. This model is known to display non-standard critical behavior on the lattice under study. The leading singular behavior of the correlation length $\xi$ near the critical coupling $K=K_c$ is modulated by a function which is periodic in $\ln|\ln(K_c-K)|$. We have also shown that the common finite-size scaling hypothesis, according to which for a finite system at criticality $\xi$ should be of the order of the size of system, is not applicable in this case. As a consequence of this, the exact form of the leading singular behavior of $\xi$ differs from the one described earlier (which was based on the finite-size scaling assumption).Comment: 9 pages (REVTEX), 2 figures (EPS), Phys. Rev. E (accepted

Dipole representation of half-filled Landau level

We introduce a variant of dipole representation for composite fermions in a half-filled Landau level, taking into account the symmetry under exchange of particles and holes. This is implemented by a special constraint on composite fermion and composite hole degree of freedom (of an enlarged space), that makes the resulting composite particle, dipole, a symmetric object. We study an effective Hamiltonian, that commutes with the constraint on the physical space, and fulfills the requirement for boost invariance on the Fermi level. The calculated Fermi liquid parameter F2 is in a good agreement with numerical investigations in [Phys. Rev. Lett. 121, 147601 (2018)].Comment: 9 pages, 4 figure

Ages of asteroid families estimated using the YORP-eye method

In the present paper we complete the analysis discussed in a previous work, using an improved algorithm and an extended database of families. We confirm that the analysis connected to the search for the YORP-eye can lead to an estimate of the age

An open architecture control system for multi‐axis wood CNC machining center

Abstract: This paper presents an open architecture control system for multi‐axis wood computer numerical control (CNC) milling machining centre, based on LinuxCNC. The wood CNC machining system is supported by an equivalent virtual machine in a CAD/CAM environment, as well as in the control system. Simulation within virtual environment is essential for multi‐axis machining, and the developed virtual machines are used for program verification and monitoring of the machining process. The virtual machine in the programming system allows the verification of the program before it’s sent to the actual machine, while the virtual machine in the control system represents the final verification of the program, as well as the process monitoring system. Configuration of the control system and implementation of virtual machines will be shown, along with the conducted machining experiments that ensued after the successful simulation on developed virtual machines

Critical behavior of loops and biconnected clusters on fractals of dimension d < 2

We solve the O(n) model, defined in terms of self- and mutually avoiding loops coexisting with voids, on a 3-simplex fractal lattice, using an exact real space renormalization group technique. As the density of voids is decreased, the model shows a critical point, and for even lower densities of voids, there is a dense phase showing power-law correlations, with critical exponents that depend on n, but are independent of density. At n=-2 on the dilute branch, a trivalent vertex defect acts as a marginal perturbation. We define a model of biconnected clusters which allows for a finite density of such vertices. As n is varied, we get a line of critical points of this generalized model, emanating from the point of marginality in the original loop model. We also study another perturbation of adding local bending rigidity to the loop model, and find that it does not affect the universality class.Comment: 14 pages,10 figure

Measuring the efficiency of Serbian insurance companies

The transition period, and the still ongoing economic crisis, amplify the volatility in the domestic insurance market and forces the management of insurance companies to continuously monitor changes in the market, i.e. to identify risks and opportunities, and therefore to undertake certain activities. The focus of the business of insurance companies is based on satisfying the needs of existing and potential clients. Respecting the current situation in the insurance market in anticipation of future events, the management of insurance companies must create and implement the optimal strategy in line with the company’s capabilities. For this purpose it is necessary to measure the efficiency of the business, which is the subject of this paper where the Data Envelopment Analysis (DEA) method is applied to the case of insurance companies operating in Serbia

Double Tooth

The form of primary and permanent teeth can differ morphologically from that which is considered normal, completely or in some parts. The changes in tooth form can be hereditary or caused by some disease or trauma. Fusion is a union of one or more teeth during development. Gemination means that two separate morphological units were created by division of the tooth germ. The intention of this study was to state the prevalence of double teeth (fusion and gemination) among the persons tested, as to gender, distribution in the maxilla or mandible, and whether the anomaly occurred bilaterally or unilaterally. The results of this investigation have shown that in a total of examined 3,517 plaster models, a prevalence of double teeth was 0.2%. 57.2% of them were fusioned and 42.9% geminated