Internet addiction in adolescents: prevalence and risk factors

As new media are becoming daily fare, Internet addiction appears as a potential problem in adolescents. From the reported negative consequences, it appears that Internet addiction can have a variety of detrimental outcomes for young people that may require professional intervention. Researchers have now identified a number of activities and personality traits associated with Internet addiction. This study aimed to synthesise previous findings by (i) assessing the prevalence of potential Internet addiction in a large sample of adolescents, and (ii) investigating the interactions between personality traits and the usage of particular Internet applications as risk factors for Internet addiction. A total of 3,105 adolescents in the Netherlands filled out a self-report questionnaire including the Compulsive Internet Use Scale and the Quick Big Five Scale. Results indicate that 3.7% of the sample were classified as potentially being addicted to the Internet. The use of online gaming and social applications (online social networking sites and Twitter) increased the 2 risk for Internet addiction, whereas extraversion and conscientiousness appeared as protective factors in high frequency online gamers. The findings support the inclusion of 'Internet addiction' in the DSM-V. Vulnerability and resilience appear as significant aspects that require consideration in further studies

A Markov model for inferring flows in directed contact networks

Directed contact networks (DCNs) are a particularly flexible and convenient class of temporal networks, useful for modeling and analyzing the transfer of discrete quantities in communications, transportation, epidemiology, etc. Transfers modeled by contacts typically underlie flows that associate multiple contacts based on their spatiotemporal relationships. To infer these flows, we introduce a simple inhomogeneous Markov model associated to a DCN and show how it can be effectively used for data reduction and anomaly detection through an example of kernel-level information transfers within a computer.Comment: 12 page

The ISIS project: Fault-tolerance in large distributed systems

The semi-annual status report covers activities of the ISIS project during the second half of 1989. The project had several independent objectives: (1) At the level of the ISIS Toolkit, ISIS release V2.0 was completed, containing bypass communication protocols. Performance of the system is greatly enhanced by this change, but the initial software release is limited in some respects. (2) The Meta project focused on the definition of the Lomita programming language for specifying rules that monitor sensors for conditions of interest and triggering appropriate reactions. This design was completed, and implementation of Lomita is underway on the Meta 2.0 platform. (3) The Deceit file system effort completed a prototype. It is planned to make Deceit available for use in two hospital information systems. (4) A long-haul communication subsystem project was completed and can be used as part of ISIS. This effort resulted in tools for linking ISIS systems on different LANs together over long-haul communications lines. (5) Magic Lantern, a graphical tool for building application monitoring and control interfaces, is included as part of the general ISIS releases

Lithuanian financial system transformation in the context of globalization

Purpose of the article: The purpose of the article is to discuss the transformation of the Lithuania finance system in the context of globalization. Exploring the interdependence between the financial system and the economy, in different periods. Analyze the country’s financial system transformation after the crisis period. Methodology/methods: Contribution use general scientific methods, especially analysis, synthesis, comparison, induction and deduction. Essential sources of information were professional publications , statistic data of state Statistics Department, Bank of Lithuania, Euro stat. Scientific aim: Main aim of this article is to analyze the transformation of the Lithuania financial system and fined out the country’s economic growth and the financial system correlation, the main factors having a both positive and negative impact on economic growth. Findings: Findings of this article are new information in this area, which can be useful for another research. The correlation between the banks‚ loans and GDP. However, this does not apply at the time of the economy fall. Conclusions: Economic growth in the financial sector and economic development is best visible analyzing in the correlation between the banks ‚ loans and GDP. However, this does not apply at the time of the economy fall. Banks ‚ relative indicators better reflects the weight of the financial sector and the impact on the national economy. We can see that 2011 banks relative indicators dropped to 2006 level. This shows how much the financial sector’s contribution decreased to economic development. Banks’ loans demand fall down. Lithuania has taken strict fiscal discipline and austerity measures. This have produced results quite quickly, in 2010 GDP grew by 3.4 percent, and in 2011 even 11.5 percent. Lithuania’s economy is recovering, but the financial sector and in particular banks still not recovering. The economic crisis has intervened in the banking system and has been surviving until now

Liquidity – Profitability Relationship Analysed with the Granger Causality Test on the Example of the Warsaw Stock Exchange

Theoretical background: The liquidity – profitability relationship is widely analysed in the literature. The surveys are based on different ratios, and different results as far as the sign of this relationship is concerned. The theory says that liquidity affects profitability but there are some findings suggesting that this relationship is reversed, namely profitability affects liquidity.Purpose of the article: The purpose of this paper is to compare the main and alternative markets of the Warsaw Stock Exchange according to the mutual influence of financial liquidity and profitability. The companies listed on those two markets are in a different stage of development and it is expected that the direction of the mutual impact of liquidity and profitability will be opposite.Research methods: The Granger causality test is applied for the data representing the financial liquidity and profitability ratios.Main findings: It was found that the mutual impact of liquidity and profitability is not opposite and profitability has a greater influence on financial liquidity in case of both markets which means that although the companies listed on the main and alternative WSE markets differ with regard to the stage of development, their management goals are the same.Theoretical background: The liquidity – profitability relationship is widely analysed in the literature. The surveys are based on different ratios, and different results as far as the sign of this relationship is concerned. The theory says that liquidity affects profitability but there are some findings suggesting that this relationship is reversed, namely profitability affects liquidity.Purpose of the article: The purpose of this paper is to compare the main and alternative markets of the Warsaw Stock Exchange according to the mutual influence of financial liquidity and profitability. The companies listed on those two markets are in a different stage of development and it is expected that the direction of the mutual impact of liquidity and profitability will be opposite.Research methods: The Granger causality test is applied for the data representing the financial liquidity and profitability ratios.Main findings: It was found that the mutual impact of liquidity and profitability is not opposite and profitability has a greater influence on financial liquidity in case of both markets which means that although the companies listed on the main and alternative WSE markets differ with regard to the stage of development, their management goals are the same

No-go theorem for bimetric gravity with positive and negative mass

We argue that the most conservative geometric extension of Einstein gravity describing both positive and negative mass sources and observers is bimetric gravity and contains two copies of standard model matter which interact only gravitationally. Matter fields related to one of the metrics then appear dark from the point of view of an observer defined by the other metric, and so may provide a potential explanation for the dark universe. In this framework we consider the most general form of linearized field equations compatible with physically and mathematically well-motivated assumptions. Using gauge-invariant linear perturbation theory, we prove a no-go theorem ruling out all bimetric gravity theories that, in the Newtonian limit, lead to precisely opposite forces on positive and negative test masses.Comment: 19 pages, no figures, journal versio

Giants at the Gate: On the Cross-section of Private Equity Investment Returns

We examine the determinants of private equity returns using a newly constructed database of 7,500 investments worldwide over forty years. The median investment IRR (PME) is 21% (1.3), gross of fees. One in ten investments goes bankrupt, whereas one in four has an IRR above 50%. Only one in eight investments is held for less than 2 years, but such investments have the highest returns. The scale of private equity firms is a significant driver of returns: investments held at times of a high number of simultaneous investments underperform substantially. The median IRR is 36% in the lowest scale decile and 16% in the highest. Results survive robustness tests. Diseconomies of scale are linked to firm structure: independent firms, less hierarchical firms, and those with managers of similar professional backgrounds exhibit smaller diseconomies of scale.Private Equity, investment, LBOs, Buyouts