12,495 research outputs found
Against the realistic interpretation of the Theory of Relativity
The Theory of Relativity has been portrayed as a theory that redefined the way we look at the cosmos, enabling us to unlock the reality we live in. Its proponents are constantly reminding us of how Einstein managed to reveal the true nature of the universe with his groundbreaking theory, which has been proved multiple times until now. Yet, philosophy of science teaches us that no theory has any privileged connection with what we call reality per se. The role of science is to formulate models of the cosmos we see and not to try to interpret or reveal reality. This paper tries to show how this holds true even for the famous relativity theory, by showing specific objections to the connection of the theory with the Holy Grail of philosophers. By analyzing various subjects related to the theory, from the twins’ paradox to the GPS satellites, this paper illustrates that relativity is much less connected to reality than what we would like to think. At the end, what Einstein’s theory provides is nothing more than a way to formalize the interactions of the world but without being able to make any claims whatsoever regarding the ‘reality’ of its conclusions
Biological invasions in agricultural settings: insights from evolutionary biology and population genetics
Invasion biology and agriculture are intimately related for several reasons and in particular because many agricultural pest species are recent invaders. In this article we suggest that the reconstruction of invasion routes with population genetics-based methods can address fundamental questions in ecology and practical aspects of the management of biological invasions in agricultural settings. We provide a brief description of the methods used to reconstruct invasion routes and describe their main characteristics. In particular, we focus on a scenario - the bridgehead invasion scenario -, which had been overlooked until recently. We show that this scenario, in which an invasive population is the source of other invasive populations, is evolutionarily parsimonious and may have played a crucial role in shaping the distribution of many recent agricultural pests
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Patterns of contribution to citizen science biodiversity projects increase understanding of volunteers’ recording behaviour
The often opportunistic nature of biological recording via citizen science leads to taxonomic, spatial and temporal biases which add uncertainty to biodiversity estimates. However, such biases may also give valuable insight into volunteers’ recording behaviour. Using Greater London as a case-study we examined the composition of three citizen science datasets – from Greenspace Information for Greater London CIC, iSpot and iRecord - with respect to recorder contribution and spatial and taxonomic biases, i.e. when, where and what volunteers record. We found most volunteers contributed few records and were active for just one day. Each dataset had its own taxonomic and spatial signature suggesting that volunteers’ personal recording preferences may attract them towards particular schemes. There were also patterns across datasets: species’ abundance and ease of identification were positively associated with number of records, as was plant height. We found clear hotspots of recording activity, the 10 most popular sites containing open water. We note that biases are accrued as part of the recording process (e.g. species’ detectability) as well as from volunteer preferences. An increased understanding of volunteer behaviour gained from analysing the composition of records could thus enhance the fit between volunteers’ interests and the needs of scientific projects
Investigating the "kink" plot as a signal of the onset of deconfinement
One of the physics goals of the NA61/SHINE collaboration at the CERN Super
Proton Synchrotron is to study the phase diagram of hadronic matter. To this
end, a series of heavy ion collision measurements are performed. It is believed
that above a certain collision energy and system size a phase transition
between hadronic matter and quark-gluon plasma occurs. A number of observables
has been developed to determine which of the phases was created at the early
stage of the collision. This report discusses the dependence of the ratio of
the mean number of produced pions to the mean number of wounded nucleons on the
Fermi energy measure. For comparison with other measurements this is often
presented in the form of the the "kink" plot. This plot is presented enriched
with preliminary results for Ar+Sc central collisions at 13A, 19A, 30A, 40A,
75A and 150A GeV/c beam momentum. The results are finally compared to data from
other experiments
Balance sheet versus earnings conservatism in Europe.
In this study we extend prior research on the international analysis of accounting conservatism (Joos and Lang, 1994; Ball et al., 2000; Giner and Rees, 2001), by examining the level of accounting conservatism across eight European countries (United Kingdom, Germany, France, Switzerland, the Netherlands, Italy, Spain and Belgium), and assessing the statistical significance of the differences among them. The definitions of conservatism that we use are, on the one hand, the Feltham and Ohlson (1995) definition, which implies a persistent understatement of book value of shareholders' equity (balance sheet conservatism). On the other hand, we use the one proposed by Basu (1997), that is, a timelier recognition of bad news in earnings relative to good news (earnings conservatism). We also address the possible scale problems of the models used to measure balance sheet conservatism. Finally, we check whether our comparative results could be influenced by a different sample composition in each country. Our results show that there are both balance sheet and earnings conservatism practices in all countries under study. In addition, while continental countries show larger balance sheet conservatism, differences in earnings conservative practices between countries are not that pronounced, although they tend to be larger in the UK. We also find that the existence of balance sheet conservative practices is associated with reduced levels of earnings conservatism, which is consistent with the results in Pope and Walker (2003).Order reprints; Request permissions;
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