Suchergebnisse

While DNA-ancestry test kits are growing in popularity, can they really tell you who you are? Here, the authors explore why identity and ancestry are not the same.

Online social networks have increasing influence on our society, they may play decisive roles in politics and can be crucial for the fate of companies. Such services compete with each other and some may even break down rapidly. Using social network datasets we show the main factors leading to such a dramatic collapse. At early stage mostly the loosely bound users disappear, later collective effects play the main role leading to cascading failures. We present a theory based on a generalised threshold model to explain the findings and show how the collapse time can be estimated in advance using the dynamics of the churning users. Our results shed light to possible mechanisms of instabilities in other competing social processes.

"Throughout Eastern Europe, the unexpected and irrevocable fall of communism that began in the late 1980s presented enormous challenges in the spheres of politics and society, as well at the level of individual experience. Excitement, uncertainty and fear predicated the shaping of a new order, the outcome of which was anything but predetermined. Recent studies have focused on the ambivalent impact of capitalism. Yet, at the time, parliamentary democracy had equally few traditions to return to, and membership in the European Union was a distant dream at best. Nowadays, as new threats arise, Europe's current political crises prompt us to reconsider how liberal democracy in Eastern Europe came about in the first place. This book undertakes an analysis of the year 1990 in several countries throughout Europe to consider the role of uncertainty and change in shaping political nations."--

Understanding attention dynamics on social media during pandemics could help governments minimize the effects. We focus on how COVID-19 has influenced the attention dynamics on the biggest Chinese microblogging website Sina Weibo during the first four months of the pandemic. We study the real-time Hot Search List (HSL), which provides the ranking of the most popular 50 hashtags based on the amount of Sina Weibo searches. We show how the specific events, measures and developments during the epidemic affected the emergence of different kinds of hashtags and the ranking on the HSL. A significant increase of COVID-19 related hashtags started to occur on HSL around January 20, 2020, when the transmission of the disease between humans was announced. Then very rapidly a situation was reached where COVID-related hashtags occupied 30–70% of the HSL, however, with changing content. We give an analysis of how the hashtag topics changed during the investigated time span and conclude that there are three periods separated by February 12 and March 12. In period 1, we see strong topical correlations and clustering of hashtags; in period 2, the correlations are weakened, without clustering pattern; in period 3, we see a potential of clustering while not as strong as in period 1. We further explore the dynamics of HSL by measuring the ranking dynamics and the lifetimes of hashtags on the list. This way we can obtain information about the decay of attention, which is important for decisions about the temporal placement of governmental measures to achieve permanent awareness. Furthermore, our observations indicate abnormally higher rank diversity in the top 15 ranks on HSL due to the COVID-19 related hashtags, revealing the possibility of algorithmic intervention from the platform provider. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1140/epjds/s13688-021-00263-0.

3. Modeling minorities in social networks -- 4. Measuring voting power and behavior in liquid democracy -- 5. Conclusions -- Science of success: An introduction -- 1. Introduction -- 2. Performance and success -- 2.1. Performance drives success -- 2.2. Perfomance is bounded -- 3. Success as a collective phenomenon -- 3.1. Success or recognition is unbounded -- 3.2. Success breeds success -- 3.3. Quality times previous success determines future success -- 4. Science of science -- 4.1. Quantifying long-term scientific impact -- 4.2. The Q-model -- 4.3. Credit is based on perception, not performance

Current forestry laws and regulations are not applicable to woody energy plantations. The cultivation technology used in these plantations differs from ones used in conventional forest management; thereby, specific legislation to regulate cultivation in woody energy plantations is required. Hungary passed its first regulations for woody energy plantations in 2007. The legislation addressed permitting, range of plantable species, planting procedures, cultivation, and plantation harvesting. The legislation overregulated coppice technology and only targeted roundwood energy plantation. The legislation does not mandate forest site surveys and its related expert opinions despite their importance in plantation establishment, particularly regarding tree species selection. The latest legislation, which improves earlier deficiencies and prescribes planting-execution plans for all plantations, came into effect 2017. Another important change is the industrial purpose categorization of woody plantations, which appeared beside coppice and roundwood energy plantations. In addition to raw material production, this type of plantation also increases the carbon sequestration of agriculture. The availability of financial resources heavily influenced plantation area size and planting intensity over the years. Investigating plantation tendencies provides an opportunity to identify forms of support that play an important role in creating the conditions for rational land use. Our research presents the effects these changes in legislation and financial support have had on energy plantations.