Nuclear angular momentum of early-type galaxies hosting nuclear star clusters

Nucleation is a common phenomenon in all types of galaxies and at least 70% of them host nuclear star clusters (NSCs) in their centres. Many of the NSCs co-habit with super-massive black holes and follow similar scaling relations with host galaxy properties. NSCs, unlike black holes, preserve the signature of their evolutionary path imprinted onto their kinematics and stellar populations. Thus their study provides us with important information about the formation of galactic nuclei. In this paper we explored the angular momentum of the nuclei of six intermediate mass (9.7 > log(Mdyn/M_sun) > 10.6) early-type galaxies in the Fornax cluster that host NSCs. Our goal was to derive a link between the nuclear angular momentum and the proposed formation scenarios of NSCs. We used Adaptive Optics assisted IFU observations with VLT/SINFONI to derive the spatially resolved stellar kinematics of the galaxy nuclei. We measured their specific stellar angular momenta ($\lambda_\mathrm{Re}$), and compared these with Milky Way globular clusters and N-body simulations of NSC formation. We found that all studied nuclei exhibit varied stellar kinematics. Their specific stellar angular momenta and ellipticities are similar to Milky Way globular clusters (GCs). Five out of six galaxy nuclei are consistent with the $\lambda_\mathrm{Re} - \epsilon_\mathrm{e}$ of simulated NSCs embedded in a contaminating nuclear bulge that have formed via the in-spiralling and merging of GCs. It has previously been suggested that the NSCs in higher mass galaxies, like the ones studied in this paper, form via dissipational sinking of gas onto the galactic nuclei with hints that some might also involve the merger of GCs. Here we showed that we cannot exclude the pure GC merging scenario as a viable path for the formation of NSCs.Comment: 8 pages, 3 figures, accepted for publication in A&

Comprehensive characterisation and modelling of the surface integrity by deep rolling on flat surface

The modern mechanical engineering is confronted with growing demands for production of high qualitative and durable products, manufactured at low costs and with short time to market. Those demands can be achieved by optimizing the product properties like lightweight, fatigue strength, corrosion resistance, etc. This thesis focuses on the characterisation of a special mechanical surface treatment called deep rolling, which can enhance the fatigue strength of the treated product by altering the material’s surface integrity as inducing favourable compressive residual stresses, a cold worked layer and by minimising the surface roughness. The available numerous deep rolling parameters, combined with the unknown material’s state inherited from previous manufacturing stages, complicate the prediction and the controlled generation of the above-mentioned treatment effects. In this work, a numerical-empirical approach for the comprehensive characterisation of surface integrity by deep rolling was defined. A finite element modelling was combined with x-ray diffraction method for the investigation of the residual stress state by variable treatment parameters and material’s state. Additionally, the cold worked amount, and the surface topography were analysed utilising finite element analysis, indentation micro-hardness method, x-ray diffraction peak widths investigations and mechanical tactile techniques. This work contributes to a better understanding of the deep rolling treatment and facilitates its integration into new product manufacturing chains.Der moderne Maschinenbau sieht sich mit wachsenden Anforderungen an die Herstel-lung qualitativ-hochwertiger und langlebiger Produkte konfrontiert, die kostengünstig und in kurzer Zeit auf den Markt gebracht werden sollen. Diese Anforderungen können durch Optimierung der Produkteigenschaften wie: Leichtgewicht, Dauerfestigkeit, Kor-rosionsbeständigkeit usw. erreicht werden. Der Schwerpunkt dieser Doktorarbeit ist die Charakterisierung einer speziellen mechanischen Oberflächenbehandlung, auch als „Festwalzen“ bezeichnet. Diese Oberflächenbehandlung kann positiv auf die Dau-erfestigkeit des behandelten Produkts wirken, mittels Erzeugung von günstigen Druckeigenspannungen, Kaltverfestigung und Minimierung der Oberflächenrauheit. Die zahlreichen verfügbaren Festwalzparameter, in Kombination mit dem unbekann-ten und aus früheren Fertigungsstufen übernommen Materialzustand, erschweren Vorhersage und kontrollierte Erzeugung der oben genannten Behandlungseffekte. In dieser Arbeit wurde ein numerisch-empirischer Ansatz zur umfassenden Charakte-risierung der Oberflächenbeschaffenheit durch Festwalzen definiert. Finite-Elemente-Modellierung wurde mit Röntgenbeugungsmethode kombiniert, um den Eigenspan-nungszustand bei variablen Behandlungsparameter und Materialzustand zu untersu-chen. Zusätzlich wurden die Kaltverfestigung sowie die Oberflächentopographie unter Verwendung von Finite-Elemente-Analyse, Mikrohärteprüfungen, Röntgenbeugungs-peakbreiten Untersuchungen und Tastschnittverfahren analysiert. Diese Arbeit trägt zu einem besseren Verständnis des Festwalzprozesses bei und erleichtert deren In-tegration in neue Produktfertigungsketten

BRAND TRUST AS A SOURCE OF BRAND EQUITY

The theoretical and empirical lack of support for including brand trust in the model of brand equity and the brand-customer relationship paradigm require further investigation of the links between the two terms. For the purposes of the current research, six proposals for operationalisation of brand trust are discussed. A novel classification of its dimensions, namely: consistency, honesty, and concern, and a hypothetical model of brand equity including brand are proposed

ECONOMIC INEQUALITY IN BULGARIA IN THE 21ST CENTURY

Research of economic inequality underlies the design and implementation of an adequate economic or social policy. This paper presents a survey of income inequality in Bulgaria in the period from 2001 to 2015 by studying the dynamics of the Gini coefficient, the integral coefficient of uneven distribution and decile ratios. We prove that despite the increase registered in the values of these indices in some years, the trend towards decreasing inequality is still weak. We also establish that there was significant income polarisation measured through the S90/10 and the S80/20 decile ratios. We prove that it is necessary to study the relation between the growth rate of the median income received by households in the first six deciles and the income received by households in the last four deciles by employing the growth rates ratio

Bulgaria’s Financial Markets In Agribusiness - Size, Structure And Development Trends

The aim of the study is to establish the size, structure and financing trends of Bulgaria’s agribusiness. Improving the liquidity and turnover of short-term assets of farms is a goal of paramount importance because it also improves profitability. This necessitates diversification of the sources and instruments to finance the operating capital, such as credits, leasing, factoring, forfeiting, etc. At micro- and macro-level, the provision of information for financial management purposes should be improved to facilitate the access to public and corporate financial markets of short-term and long-term funds for the agribusiness. Public financial markets in Bulgaria’s agribusiness grew steadily from over BGN 1 billion/year during the first reference period of the common agricultural policy of the EU (2007–2013) to BGN 4 billion/year at the end of the 2014–2020 period. They also played an important role in generating reciprocal company financing of over BGN 3 billion/year of over BGN 7 billion/year of all financing in the sector. Structurally, short-term financing accounts for more than 2/3 to 3/4 of all financing

Biotests in Ecotoxicology: Current Practice and Problems

Nowadays ecotoxicology plays the role of a theoretician – methodical unifying centre for the optimization of man – biosphere relations and sustainable existence of life on the Earth. The main basis for its development is the classical toxicology—studies of chemical compounds’ effects on man, but ecotoxicology is the original part, following it. According to the modern concept, the ecotoxicology is a science for migration, transformation and utilization of different toxic ingredients (with organic, inorganic or organic-mineral chemical nature; with natural biotic or abiotic origin and artificial, mainly anthropogenic origin) in the environment and their impact on Macro- biological systems with different levels of integration as groups of individuals, population, community, ecosystem, etc. studied in ecology. In this chapter, the types of ecotoxicological tests are discussed in detail with a set of examples about used species, advantages and disadvantages of different types of toxicity testing. The application of exposed natural ecosystems or man-made analogue systems is also commented as the environmentally more realistic approach for ecotoxicological testing. These test systems are increasingly becoming in aquatic ecotoxicology practice, but they are contemporary challenge in terrestrial testing. The development of test systems for realistic assessment of contaminant toxicity is essential for the efficient control of human influence on the environment

Full-field stress analysis by holographic phase-stepping implementation of the photoelastic-coating method

In this paper, we describe a system for polariscopic and holographic phase-shifting implementation of the photoelastic-coating method for a full-field stress analysis. The easiest way to build the combined system is to employ a laser light source. However, coherent illumination introduces a signal-dependent speckle noise which worsens the accurate phase estimation and unwrapping. To answer the question of how it affects the phase retrieval of isochromatics, isoclinics and isopachics, we modeled in the present paper the phase-shifting photoelastic measurement in the presence of speckle noise through the calculation of the complex amplitudes in a Mach-Zender interferometer combined with a circular polariscope and made denoising of simulated and experimental fringe patterns. The latter were recorded at pure tensile load for PhotoStress (R)-coated samples with a mechanical stress concentrator

The inner mass distribution of late-type spiral galaxies from SAURON stellar kinematic maps

We infer the central mass distributions within 0.4-1.2 disc scale lengths of 18 late-type spiral galaxies using two different dynamical modelling approaches - the Asymmetric Drift Correction (ADC) and axisymmetric Jeans Anisotropic Multi-gaussian expansion (JAM) model. ADC adopts a thin disc assumption, whereas JAM does a full line-of-sight velocity integration. We use stellar kinematics maps obtained with the integral-field spectrograph SAURON to derive the corresponding circular velocity curves from the two models. To find their best-fit values, we apply Markov Chain Monte Carlo (MCMC) method. ADC and JAM modelling approaches are consistent within 5% uncertainty when the ordered motions are significant comparable to the random motions, i.e, $\overline{v_{\phi}}/\sigma_R$ is locally greater than 1.5. Below this value, the ratio $v_\mathrm{c,JAM}/v_\mathrm{c,ADC}$ gradually increases with decreasing $\overline{v_{\phi}}/\sigma_R$, reaching $v_\mathrm{c,JAM}\approx 2 \times v_\mathrm{c,ADC}$. Such conditions indicate that the stellar masses of the galaxies in our sample are not confined to their disk planes and likely have a non-negligible contribution from their bulges and thick disks.Comment: 44 pages, 60 figures, MNRAS accepted. The ADC-MCMC and JAM-MCMC python codes are available at: https://github.com/Kalinova/Dyn_models. The Multi-Gaussian Expansion (MGE) results are also available in the Appendi

Financial Issues And Funding In The Bulgarian Beekeeping Sector

The aim of the study is to establish the amount of funding in Bulgarian beekeeping and their trends. The goal is achived through an analysis of the tendencies and the main sources of financial means. The study analyses the financial support from European and national funds (the National Beekeeping Program, the de minimis scheme, the Rural Development Program) for over BGN 18 million and from commercial banks and own sources for over BGN 3 million. Together they form financial markets for over BGN 21 million a year in Bulgarian beekeeping. The European and state financial resources intended for Bulgarian beekeeping from the country's membership in the EU are increasing in absolute terms, but are decreasing relative to the total funds. Bulgarian beekeeping has gained access to additional funding, which is not proportionate in comparison with other sectors. Additional financial support is needed per hive for the ecosystem pollination service in order to ensure biodiversity and food security in the EU. The financing of the Bulgarian beekeeping will continue to grow steadily