Search results for " Evolution"
showing 10 items of 9699 documents
Shell evolution above Z,N=50 within Skyrme density functional theory: The impact of deformation and tensor interactions
2017
Background: Recent years have seen considerable effort in associating the shell evolution (SE) for a chain of isotones or isotopes with the underlying nuclear interactions. In particular, it has been fairly well established that the tensor part of the Skyrme interaction is indispensable for understanding certain SE above Z,N = 50 shell closures, as a function of nucleon numbers. Purpose: The purpose of the present work is twofold: (1) to study the effect of deformation due to blocking on the SE above Z,N = 50 shell closures and (2) to examine the optimal parametrizations in the tensor part which gives a proper description of the SE above Z,N = 50 shell closures. Methods: I use the Skyrme-Ha…
(no title)
2017
Biological invasions are recognized as a significant evolutionary factor over short time scales. In particular, their effect is well recorded on the genetic structure of populations, the patterns of phenotypic evolution and the richness of parasite fauna associated to invasive populations. This study aims at quantifying the consequences of a biological invasion according to these three levels (genetical, phenotypical and parasitological) taking as example the Mozambique tilapia Oreochromis mossambicus. This African cichlid is characterized by an unusual conservation status since it is both (i) ranked among the world's worst invasive species due to its global dispersion during the 20th centu…
To correct or to cooperate : Mediational processes and L2 development
2018
The present article argues for a conceptual distinction between corrective feedback and mediation that emphasizes the status of the latter not as an instructional practice but as a defining feature of human psychology (Vygotsky, 1987) that has direct implications for how instruction might be approached. Specifically, Sociocultural Theory (SCT) posits that humans are always and everywhere mediated, as individuals draw upon meanings and ways of thinking they have already internalized as well as those that are available in their immediate environment to regulate their actions. With regard to second language (L2) education, rather than exclusively focusing on learner independent performance or…
Environmental effects on the covariation among pace-of-life traits
2019
Pace‐of‐life syndromes (POLSs) are suites of life‐history, physiological and behavioural traits that arise due to trade‐offs between allocation to current and future reproduction. Traits generally show covariation that can arise from genetic and environmental influences on phenotypes and constrain the independent evolution of traits, resulting in fitness consequences and impacts on population dynamics. The notion that correlations among traits may vary among populations along environmental gradients suggests an important role for the environment in shaping and maintaining POLSs. However, no synthesis has been attempted of the myriad ways in which environmental factors should influence POLSs…
Diversification in evolutionary arenas - assessment and synthesis
2019
Abstract Understanding how and why rates of evolutionary diversification vary is a central issue in evolutionary biology and ecology. The concept of adaptive radiation has attracted much interest, but is metaphorical and verbal in nature, making it difficult to quantitatively compare different evolutionary lineages or geographic regions. In addition, the causes of evolutionary stasis are relatively neglected. Here we review the central concepts in the evolutionary diversification literature and bring these together by proposing a general framework for estimating rates of diversification and quantifying their underlying dynamics, which can be applied across clades and regions and across spat…
Evolutionary advantage conferred by an eukaryote-to-eukaryote gene transfer event in wine yeasts
2015
Although an increasing number of horizontal gene transfers have been reported in eukaryotes, experimental evidence for their adaptive value is lacking. Here, we report the recent transfer of a 158-kb genomic region between Torulaspora microellipsoides and Saccharomyces cerevisiae wine yeasts or closely related strains. This genomic region has undergone several rearrangements in S. cerevisiae strains, including gene loss and gene conversion between two tandemly duplicated FOT genes encoding oligopeptide transporters. We show that FOT genes confer a strong competitive advantage during grape must fermentation by increasing the number and diversity of oligopeptides that yeast can utilize as a s…
Comparison of wormlion behavior under man-made and natural shelters: urban wormlions more strongly prefer shaded, fine-sand microhabitats, construct …
2019
Abstract Urban habitats differ from their natural surroundings in various aspects, such as a higher temperature and a distinct species composition. It is therefore not surprising that animal behavior too differs between these habitat types. We studied the foraging and habitat selection behavior of a pit-building predator, a wormlion, originating from either an urban or a more natural site. Wormlions occur in nature under structures that provide shelter from sunlight and rain, such as caves, and are also common in cities, occurring under artificial shelters. Wormlions construct pit-traps to hunt arthropods, and the pits constructed by urban wormlions were larger than those constructed by wor…
Using machine learning on tree-ring data to determine the geographical provenance of historical construction timbers
2023
Funder: Bavarian Climate Research Network (BayKliF)
Upper thermal threshold of Lepidurus arcticus (Branchiopoda, Notostraca) in lakes on the southern outreach of its distribution range
2021
Qvenild T, Fjeld E, Fjellheim A, Hammar J, Hesthagen T and Lakka H-K. 2021. Upper thermal threshold of Lepidurus arcticus (Branchiopoda, Notostraca) in lakes on the southern outreach of its distribution range. Fauna norvegica 41: 50–88. The Arctic tadpole shrimp Lepidurus arcticus has a circumpolar distribution and the Scandes (Fennoscandian Mountains) marks its southernmost limit in Europe. Within this area, 391 natural and 88 regulated lakes with L. arcticus have been identified, of which 87% are above the treeline. The lakes hosting L. arcticus decrease in altitude from south to north, which results from its temperature preferences. The majority of the locations are at a lower lake air t…
Semi-natural habitats in boreal Europe: a rise of a social-ecological research agenda
2021
The European continent contains substantial areas of semi-natural habitats, mostly grasslands, which are among the most endangered habitats in Europe. Their continued existence depends on some form of human activity, for either production or conservation purposes, or both. We examined the share of semi-natural grasslands within the general grassland areas in boreal Europe. We reviewed research literature across the region to compile evidence on semi-natural grasslands and other semi-natural habitats, such as wooded pastures, in respect to a range of topics such as ecology, land-use change, socioeconomics, and production. We also explored drivers of the research agenda and outlined future re…