Filamentary fragmentation in a turbulent medium

We present the results of smoothed particle hydrodynamic simulations investigating the evolution and fragmentation of filaments that are accreting from a turbulent medium. We show that the presence of turbulence, and the resulting inhomogeneities in the accretion flow, play a significant role in the fragmentation process. Filaments which experience a weakly turbulent accretion flow fragment in a two-tier hierarchical fashion, similar to the fragmentation pattern seen in the Orion Integral Shaped Filament. Increasing the energy in the turbulent velocity field results in more sub-structure within the filaments, and one sees a shift from gravity-dominated fragmentation to turbulence-dominated fragmentation. The sub-structure formed in the filaments is elongated and roughly parallel to the longitudinal axis of the filament, similar to the fibres seen in observations of Taurus, and suggests that the fray and fragment scenario is a possible mechanism for the production of fibres. We show that the formation of these fibre-like structures is linked to the vorticity of the velocity field inside the filament and the filament's accretion from an inhomogeneous medium. Moreover, we find that accretion is able to drive and sustain roughly sonic levels of turbulence inside the filaments, but is not able to prevent radial collapse once the filaments become supercritical. However, the supercritical filaments which contain fibre-like structures do not collapse radially, suggesting that fibrous filaments may not necessarily become radially unstable once they reach the critical line-density.Comment: (Accepted for publication in MNRAS

The role of human resources on the economy: a study of the Balkan eu member states

In this paper we analyze the impact of the quality of human capital on the main economic indicators of South-Eastern Europe countries [SEE] at the NUTS 2 level. The subjects of this research are the human capital indicators of regional competitiveness. The quality of human capital depends largely on the age structure of the population and the quality of education. Those regions, which have the highest percentage of the working-age population and highly educated people, are able to achieve higher productivity and gain a competitive advantage over other regions. As main indicators of the quality of human capital we identified: population; persons aged 25-64 with tertiary education attainment; students in tertiary education and participation of adults aged 25-64 in education and training and human resources in science and technology. As main economic indicators, we identified: regional gross domestic product; employment and income of households. The aim of this paper is to determine whether there is a correlation between the indicators of the quality of human capital and economic indicators. As a main methodology we have used the correlation coefficient which shows interdependence of the analyzed indicators. As part of our analysis, we consider only EU member states that belong to the SEE countries: Slovenia, Croatia, Romania, Bulgaria and Greece. We conclude that in all countries there is a high multiple correlation coefficient between the indicators human resources in science and technology, number of students and employment.This paper is the result of the project No. 47007 III funded by the Ministry for Education, Science and Technological Development of Republic of Serbia

Gluon and Ghost Dynamics from Lattice QCD

The two point gluon and ghost correlation functions and the three gluon vertex are investigated, in the Landau gauge, using lattice simulations. For the two point functions, we discuss the approach to the continuum limit looking at the dependence on the lattice spacing and volume. The analytical structure of the propagators is also investigated by computing the corresponding spectral functions using an implementation of the Tikhonov regularisation to solve the integral equation. For the three point function we report results when the momentum of one of the gluon lines is set to zero and discuss its implications.Comment: Proceedings of Light Cone 2016, held in Lisbon, September 2016. Minor changes in text. To appear in Few B Sy

Statistical mixing and aggregation in Feller diffusion

We consider Feller mean-reverting square-root diffusion, which has been applied to model a wide variety of processes with linearly state-dependent diffusion, such as stochastic volatility and interest rates in finance, and neuronal and populations dynamics in natural sciences. We focus on the statistical mixing (or superstatistical) process in which the parameter related to the mean value can fluctuate - a plausible mechanism for the emergence of heavy-tailed distributions. We obtain analytical results for the associated probability density function (both stationary and time dependent), its correlation structure and aggregation properties. Our results are applied to explain the statistics of stock traded volume at different aggregation scales.Comment: 16 pages, 3 figures. To be published in Journal of Statistical Mechanics: Theory and Experimen

Relationship between buyer and supplier in outsourcing of information technology services

Companies rely on others to achieve its goals. This is not only true in terms of management of the flows of information and materials through the supply chain but also in terms of performing specific processes and sub-processes intimately related to the company’s operation. IT Outsourcing (ITO) is increasing worldwide and the relational governance impacts the outsourcing outcomes (Lacity et al, 2016). This perspective is usually visited for the buyer and supplier perspectives using decision makers and leaving a gap in literature in terms of the perspective of the consultants. This paper aims at analysing, in ITO, how the development of the relationship between buyer and supplier strengthens supplier performance over time, from the perspective of the consultants. A survey to IT consultants was applied and then a multilevel analysis was performed, taking account for the aggregate values of the variables characterizing buyer supplier relationships based on Johnston and Staughton (2009), Krause et al. (2007) and Blonska et al. (2013). Findings show that strategic relationships are associated with higher supplier investment in relational management. In this type of relationship higher levels of trust are linked to an attribution of more recognised benefits from the relationship, and reciprocal investment to the buyer. Furthermore, an improvement of the dedication in the relation and an improved service performance were attributed by IT consultants to the supplier.info:eu-repo/semantics/publishedVersio

Satisfação com as práticas de gestão de recursos humanos e intenção de turn over num hotel de cinco estrelas: o papel mediador da perceção de suporte organizacional

Employees’ satisfaction with human resources management (HRM) practices has been envisaged as a solid predictor of turnover; nonetheless, how these practices may influence employee’s behavior is still an unclear process. There are suggestions that HRM practices may be distal determinants of turnover, as their effects may be mediated by more proximal variables such as perceived organizational support. This study empirically tested a model of research arising from these theoretical suggestions in a five-star hotel. The data collected from the survey of 152 workers were subjected to structural equation analyses. The results showed that the theoretical model had a strong fit to the data, giving empirical support to the prediction that satisfaction with HRM practices reduces turnover intentions, by increasing perceived organizational support. The importance of these results is discussed and interpreted from the point of view of strategic gains associated to the quality of HRM practices for the management of voluntary turnover.info:eu-repo/semantics/publishedVersio