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Theoretical ecologists have long sought to understand how the persistence of populations depends on the interactions between exogenous (biotic and abiotic) and endogenous (e.g., demographic and genetic) drivers of population dynamics. Recent work focuses on the autocorrelation structure of environmental perturbations and its effects on the persistence of populations. Accurate estimation of extinct
The Baltic Sea has experienced three major intervals of bottom water hypoxia following the intrusion of seawater circa 8 kyr ago. These intervals occurred during the Holocene Thermal Maximum (HTM), Medieval Climate Anomaly (MCA), and during recent decades. Here we show that sequestration of both Fe and Mn in Baltic Sea sediments generally increases with water depth, and we attribute this to shelf-
BACKGROUND: Patterns of spatial variation in discrete phenotypic traits can be used to draw inferences about the adaptive significance of traits and evolutionary processes, especially when compared to patterns of neutral genetic variation. Population divergence in adaptive traits such as color morphs can be influenced by both local ecology and stochastic factors such as genetic drift or founder ev
Global patterns in soil, plant, and fungal stable isotopes of N (delta N-15) show promise as integrated metrics of N cycling, particularly the activity of ectomycorrhizal (ECM) fungi. At small spatial scales, however, it remains difficult to differentiate the underlying causes of plant delta N-15 variability and this limits the application of such measurements to better understand N cycling. We co
Agricultural management and vegetation complexity affect arthropod diversity and may alter trophic interactions between predators and their prey. Web-building spiders are abundant generalist predators and important natural enemies of pests. We analyzed how management intensity (tillage, cutting of the vegetation, grazing by cattle, and synthetic and organic inputs) and vegetation complexity (plant
A spinel-type catalyst of the composition Fe(2.50(1-z/3))V(0.20(1-z/3))Mo(0.30(1-z/3))square(z)O(4), where z is the number of cation vacancies (El), was prepared under reducing atmosphere. From the reduced sample a number of preoxidized samples were made by TPO treatment of the reduced material to different end temperatures ranging from 150 to 450 degrees C. XRD shows that the spinel-type structur
This work presents studies of the valence band of two Kondo lattice systems: Ce2Co0.8Si3.2, which is paramagnetic with the Kondo temperature T-K approximate to 50 K and Ce2RhSi3, which is antiferromagnetic below T-N = 4.5 K and exhibits TK approximate to 9 K. The photoemission spectra, which are obtained with photon energy tuned to Ce - 4d 4f resonance, reveal a Kondo peak at the Fermi energy (E-F
The large bloom-forming flagellate Gonyostomum semen has been hypothesized to be inedible to naturally occurring zooplankton due to its large cell size and ejection of long slimy threads (trichocysts) induced by physical stimulation. In a grazing experiment using radiolabelled algae and zooplankton collected from lakes with recurring blooms of G. semen and lakes that rarely experience blooms, we f
We used a nested PCR protocol to examine the genetic diversity of cytochrome b (cyt b) lineages from blood parasites of the genera Plasmodium and Haemoproteus in birds in Bulgaria. In total, 460 birds of 43 species and 14 families (mostly passerines) were examined for the presence of infections. Of them, 267 were recognised as infected with haemosporidian parasites. Mixed infections were recorded
Dissolved organic carbon (DOC) is one of the most active and mobile carbon pools, and thus an important component of the global carbon cycle. Previous research on DOC transport in the soil and on factors controlling DOC export towards the river system focused mainly on forest and wetland areas, with only limited information available from agricultural soils. We carried out rainfall simulations on
I denna uppsats behandlas satsadverbialen inte, nog och visst. De undersöks, var för sig, i två positioner i satsen, nämligen fundamentet och den typiska satsadverbials¬positionen (A1). Syftet är att beskriva adverbialens möjliga betydelser i respektive position. Utifrån hur de, i olika talsituationer och kontexter, inverkar på talarens inställning till satsens proposition i fundamentet och i A1,
Despite increasing recognition of the relevance of biological cycling for Si cycling in ecosystems and for Si export from soils to fluvial systems, effects of human cultivation on the Si cycle are still relatively understudied. Here we examined stable Si isotope (delta Si-30) signatures in soil water samples across a temperate land use gradient. We show that - independent of geological and climato
Objectives To determine the detection rate of fetal malformations and chromosomal abnormalities and the rate of false-positive ultrasound diagnoses at routine ultrasound examinations carried out by specially trained midwives in an unselected pregnant population front 2000 to 2005, and to describe the consequences of true-positive and false-positive ultrasound diagnoses of fetal malformations. Meth
Abstract in UndeterminedThe upwelling region off northwest Africa is one of the most productive regions in the world ocean. This study details the response of surface-and deep-water environments off Mauritania, northwest Africa, to the rapid climate events of the last deglaciation, especially the Bolling-Allerod (15.5-13.5 ka BP) and Younger Dryas (13.5-11.5 ka BP). A high accumulation rate gravit
Increasing restrictions on hazardous emissions combined with demands for good profitability from the operators in the energy market have contributed strongly to the development of innovations in which the emphasis is on low emissions and high efficiency. For gas turbine-based power plants, emission of NOx in particular is governed by stringent legislation. To meet these restrictions, most of the m
Knowledge of the processes favouring the establishment of exotic parasites is poor. Herein, we test the characteristics of successful exotic parasites that have co-established in the remote island archipelago of New Zealand, due to the introduction of numerous avian host species. Our results show that avian malaria parasites (AM; parasites of the genus Plasmodium) that successfully invaded are mor
In cases in which experimental data on chemical-specific input parameters are lacking, chemical regulations allow the use of alternatives to testing, such as in silico predictions based on quantitative structureproperty relationships (QSPRs). Such predictions are often given as point estimates; however, little is known about the extent to which uncertainties associated with QSPR predictions contri
The evolution of natural organisms is ultimately driven by the invasion and possible fixation of mutant alleles. The invasion process is highly stochastic, however, and the probability of success is generally low, even for advantageous alleles. Additionally, all organisms live in a stochastic environment, which may have a large influence on what alleles are favorable, but also contributes to the u
Social information is used widely in breeding habitat selection and provides an efficient means for individuals to select habitat, but the population-level consequences of this process are not well explored. At low population densities, efficiencies may be reduced because there are insufficient information providers to cue high-quality habitat. This constitutes what we call an information-mediated
