Browsing by Subject "LIMITS"

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  • Rutkowski, Tomasz; Maak, Istvsn; Vepsäläinen, Kari; Trigos-Peral, Gema; Stephan, Wojciech; Wojtaszyn, Grzegorz; Czechowski, Wojciech (2019)
    Successful evacuation of a peculiar 'colony' of the wood ant Formica polyctena Forst., for years trapped within an old bunker previously used for storing nuclear weapons (see Czechowski et al. 2016), is reported. Using an experimentally installed boardwalk, the imprisoned ants managed to get through the ventilation pipe to their maternal nest on the top of the bunker. In our previous report, we left open the question of how the 'colony' could survive seemingly without food. Here we show that the 'colony' in the bunker survived and grew thanks to an influx of workers from the source nest above the bunker and mass consumption of corpses of the imprisoned nestmates.
  • Holma, Maija; Lindroos, Marko; Romakkaniemi, Atso; Oinonen, Soile (2019)
  • Oishi, Tomohiro; Kortelainen, Markus; Pastore, Alessandro (2017)
    Sensitivity of two-proton emitting decay to nuclear pairing correlation is discussed within a time-dependent three-body model. We focus on the Be-6 nucleus assuming alpha + p + p configuration, and its decay process is described as a time evolution of the three-body resonance state. For a proton-proton subsystem, a schematic density-dependent contact (SDDC) pairing model is employed. From the time-dependent calculation, we observed the exponential decay rule of a two-proton emission. It is shown that the density dependence does not play a major role in determining the decay width, which can be controlled only by the asymptotic strength of the pairing interaction. This asymptotic pairing sensitivity can be understood in terms of the dynamics of the wave function driven by the three-body Hamiltonian, by monitoring the time-dependent density distribution. With this simple SDDC pairing model, there remains an impossible trinity problem: it cannot simultaneously reproduce the empirical Q value, decay width, and the nucleon-nucleon scattering length. This problem suggests that a further sophistication of the theoretical pairing model is necessary, utilizing the two-proton radioactivity data as the reference quantities.
  • Ruuska, Toni; Heikkurinen, Pasi; Wilen, Kristoffer (2020)
    In this article, we study politics as domination. From our point of view, domination, especially in the Anthropocene, has had two vital components-power and supremacy. In order to dominate, one has to have power over others. In addition, the politics of domination, such as colonial oppression of Latin America, has required reasoning, justification, and legitimation, often connected to superiority (because of religion, society, or civilization) from the oppressor's end. Past and present political ideologies and programs, such as colonialism, imperialism, but also welfare state capitalism, neoliberalism and increasingly popular Green New Deal are examples of what we call "anthropolitics", an anthropocentric approach to politics based on domination, power, and supremacist exploitation. In contrast to the prevailing anthropolitics, this article discusses post-Anthropocene politics, characterized by localization and decentralization, as well as a steep reduction of matter-energy throughput by introducing a theoretical frame called ecological realism.
  • Hindmarsh, Mark; Rummukainen, Kari; Weir, David J. (2017)
    We perform the first numerical simulations of necklaces in a non-Abelian gauge theory. Necklaces are composite classical solutions which can be interpreted as monopoles trapped on strings, rather generic structures in a Grand Unified Theory. We generate necklaces from random initial conditions, modeling a phase transition in the early Universe, and study the evolution. For all cases, we find that the necklace system shows scaling behavior similar to that of a network of ordinary cosmic strings. Furthermore, our simulations indicate that comoving distance between the monopoles or semipoles along the string asymptotes to a constant value at late times. This means that, while the monopole-to-string energy density ratio decreases as the inverse of the scale factor, a horizon-size length of string has a large number of monopoles, significantly affecting the dynamics of string loops. We argue that gravitational wave bounds from millisecond pulsar timing on the string tension in the Nambu-Goto scenario are greatly relaxed.
  • Batista, Romina; Olsson, Urban; Andermann, Tobias; Aleixo, Alexandre; Ribas, Camila Cherem; Antonelli, Alexandre (2020)
    To elucidate the relationships and spatial range evolution across the world of the bird genus Turdus (Aves), we produced a large genomic dataset comprising ca 2 million nucleotides for ca 100 samples representing 53 species, including over 2000 loci. We estimated time-calibrated maximum-likelihood and multispecies coalescentphylogenies and carried out biogeographic analyses. Our results indicate that there have been considerably fewer trans-oceanic dispersals within the genus Turdus than previously suggested, such that the Palaearctic clade did not originate in America and the African clade was not involved in the colonization of the Americas. Instead, our findings suggest that dispersal from the Western Palaearctic via the Antilles to the Neotropics might have occurred in a single event, giving rise to the rich Neotropical diversity of Turdus observed today, with no reverse dispersals to thePalaearctic or Africa. Our large multilocus dataset, combined with dense species-level sampling and analysed under probabilistic methods, brings important insights into historical biogeography and systematics, even in a scenario of fast and spatially complex diversification.
  • Westerbom, Mats; Mustonen, Olli; Jaatinen, Kim; Kilpi, Mikael; Norkko, Alf (2019)
    Examining changes in abundance and demographic rates at species distribution margins may provide the first signs of broader species responses to environmental change. Still, the joint impact of space and time have remained relatively unstudied in most marginal regions. In order to examine the influence of climate variability on mussel distribution patterns, we monitored three sublittoral and marginal blue mussel (Mytilus trossulus) populations, spaced along a salinity gradient. Densities and biomasses peaked toward the saltier parts of the study area and showed relatively larger variations toward the low saline edge. Temporally, the areas showed a consistent increase in abundance after a synchronized large-scale recruitment event, which was followed by a decline in population size, occurring much faster toward the very range edge. Salinity, temperature, winter severity, and wave exposure explained most of the spatiotemporal variation in mussel abundances and adults showed positive effects on recruit abundance. We show empirically that the dynamics of edge populations are not driven by large changes in climate variables but that small spatial and temporal changes in key environmental variables have large and non-linear population level effects. Our results also show that fluctuating recruitment is a key factor for population stability affecting the storage potential of marginal populations, which dramatically decrease toward the edge. Our study provides a window into future population patterns and processes that drive marginal mussel populations in an altered sea characterized by rising temperature and declining salinity.
  • Byrnes, Christian T.; Hindmarsh, Mark; Young, Sam; Hawkins, Michael R. S. (2018)
    Making use of definitive new lattice computations of the Standard Model thermodynamics during the quantum chromodynamic (QCD) phase transition, we calculate the enhancement in the mass distribution of primordial black holes (PBHs) due to the softening of the equation of state. We find that the enhancement peaks at approximately 0.7 M-circle dot, with the formation rate increasing by at least two orders of magnitude due to the softening of the equation of state at this time, with a range of approximately 0.3 M-circle dot <M <1.4 M-circle dot at full width half-maximum. PBH formation is increased by a smaller amount for PBHs with masses spanning a large range, 10(-3) M-circle dot <M-PBH <10(3) M-circle dot, which includes the masses of the BHs that LIGO detected. The most significant source of uncertainty in the number of PBHs formed is now due to unknowns in the formation process, rather than from the phase transition. A near scale-invariant density power spectrum tuned to generate a population with mass and merger rate consistent with that detected by LIGO should also produce a much larger energy density of PBHs with solar mass. The existence of BHs below the Chandresekhar mass limit would be a smoking gun for a primordial origin and they could arguably constitute a significant fraction of the cold dark matter density. They also pose a challenge to infiationary model building which seek to produce the LIGO BHs without overproducing lighter PBHs.
  • Garate-Escamilla, Homero; Hampe, Arndt; Vizcaino-Palomar, Natalia; Robson, T. Matthew; Garzon, Marta Benito (2019)
    Aim To better understand and more realistically predict future species distribution ranges, it is critical to account for local adaptation and phenotypic plasticity in populations' responses to climate. This is challenging because local adaptation and phenotypic plasticity are trait-dependent and traits covary along climatic gradients, with differential consequences for fitness. Our aim is to quantify local adaptation and phenotypic plasticity of vertical and radial growth, leaf flushing and survival across the range of Fagus sylvatica and to estimate the contribution of each trait to explaining the species' occurrence. Location Europe. Time period 1995-2014; 2070. Major taxa studied Fagus sylvatica L. Methods We used vertical and radial growth, flushing phenology and mortality of F. sylvatica L. recorded in the BeechCOSTe52 database (>150,000 trees). Firstly, we performed linear mixed-effect models that related trait variation and covariation to local adaptation (related to the planted populations' climatic origin) and phenotypic plasticity (accounting for the climate of the plantation), and we made spatial predictions under current and representative concentration pathway (RCP 8.5) climates. Secondly, we combined spatial trait predictions in a linear model to explain the occurrence of the species. Results The contribution of plasticity to intraspecific trait variation is always higher than that of local adaptation, suggesting that the species is less sensitive to climate change than expected; different traits constrain beech's distribution in different parts of its range: the northernmost edge is mainly delimited by flushing phenology (mostly driven by photoperiod and temperature), the southern edge by mortality (mainly driven by intolerance to drought), and the eastern edge is characterized by decreasing radial growth (mainly shaped by precipitation-related variables in our model); considering trait covariation improved single-trait predictions. Main conclusions Population responses to climate across large geographical gradients are dependent on trait x environment interactions, indicating that each trait responds differently depending on the local environment.