| 1. |
- Santoro, V., et al.
(author)
-
HighNESS conceptual design report: Volume I
- 2024
-
In: Journal of Neutron Research. - 1023-8166 .- 1477-2655. ; 25:3-4, s. 85-314
-
Journal article (peer-reviewed)abstract
- The European Spallation Source, currently under construction in Lund, Sweden, is a multidisciplinary international laboratory. Once completed to full specifications, it will operate the world’s most powerful pulsed neutron source. Supported by a 3 million Euro Research and Innovation Action within the EU Horizon 2020 program, a design study (HighNESS) has been completed to develop a second neutron source located below the spallation target. Compared to the first source, designed for high cold and thermal brightness, the new source has been optimized to deliver higher intensity, and a shift to longer wavelengths in the spectral regions of cold (CN, 2–20 Å), very cold (VCN, 10–120 Å), and ultracold (UCN, >500 Å) neutrons. The second source comprises a large liquid deuterium moderator designed to produce CN and support secondary VCN and UCN sources. Various options have been explored in the proposed designs, aiming for world-leading performance in neutronics. These designs will enable the development of several new instrument concepts and facilitate the implementation of a high-sensitivity neutron-antineutron oscillation experiment (NNBAR). This document serves as the Conceptual Design Report for the HighNESS project, representing its final deliverable.
|
|
| 2. |
- Santoro, V., et al.
(author)
-
HighNESS conceptual design report: Volume II. the NNBAR experiment.
- 2024
-
In: Journal of Neutron Research. - 1023-8166 .- 1477-2655. ; 25:3-4, s. 315-406
-
Journal article (peer-reviewed)abstract
- A key aim of the HighNESS project for the European Spallation Source is to enable cutting-edge particle physics experiments. This volume presents a conceptual design report for the NNBAR experiment. NNBAR would exploit a new cold lower moderator to make the first search in over thirty years for free neutrons converting to anti-neutrons. The observation of such a baryon-number-violating signature would be of fundamental significance and tackle open questions in modern physics, including the origin of the matter-antimatter asymmetry. This report shows the design of the beamline, supermirror focusing system, magnetic and radiation shielding, and anti-neutron detector necessary for the experiment. A range of simulation programs are employed to quantify the performance of the experiment and show how background can be suppressed. For a search with full background suppression, a sensitivity improvement of three orders of magnitude is expected, as compared with the previous search. Civil engineering studies for the NNBAR beamline are also shown, as is a costing model for the experiment.
|
|
| 3. |
- Cucherousset, J., et al.
(author)
-
Growth-enhanced salmon modify stream ecosystem functioning
- 2021
-
In: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 99:6, s. 1978-1989
-
Journal article (peer-reviewed)abstract
- Use of fast-growing domesticated and/or genetically modified strains of fish is becoming increasingly common in aquaculture, increasing the likelihood of deliberate or accidental introductions into the wild. To date, their ecological impacts on ecosystems remain to be quantified. Here, using a controlled phenotype manipulation by implanting growth hormone in juvenile Atlantic salmon (Salmo salar), we found that growth-enhanced fish display changes in several phenotypic traits known to be important for ecosystem functioning, such as habitat use, morphology and excretion rate. Furthermore, these phenotypic changes were associated with significant impacts on the invertebrate community and key stream ecosystem functions such as primary production and leaf-litter decomposition. These findings provide novel evidence that introductions of growth-enhanced fish into the wild can affect the functioning of natural ecosystems and represent a form of intraspecific invasion. Consequently, environmental impact assessments of growth-enhanced organisms need to explicitly consider ecosystem-level effects.
|
|
| 4. |
- Zavorka, L., et al.
(author)
-
Laboratory captivity can affect scores of metabolic rates and activity in wild brown trout
- 2019
-
In: Journal of Zoology. - : Wiley. - 0952-8369 .- 1469-7998. ; 307:4, s. 249-255
-
Journal article (peer-reviewed)abstract
- Phenotypic scoring of wild animals under standardized laboratory conditions is important as it allows field ecologists and evolutionary biologists to understand the development and maintenance of interindividual differences in plastic traits (e.g. behaviour and physiology). However, captivity is associated with a shift from a natural familiar environment to an unfamiliar and artificial environment, which may affect estimates of plastic phenotypic traits. In this study, we tested how previous experience with laboratory environments and time spent in captivity affects behavioural (i.e. activity) and metabolic (i.e. standard and maximum metabolic rates) scoring of our model species, wild brown trout Salmo trutta. We found that individuals with previous experience of laboratory captivity (10.5 months earlier) showed higher activity in an open field test than individuals with no prior experience of laboratory captivity. Previous experience with captivity had no significant effect on metabolic rates. However, metabolic rates seemed to increase with increasing time spent in captivity prior to the collection of measurements. Although there are benefits of keeping wild animals in captivity prior to scoring, our results suggest that while allowing for sufficient acclimatization researchers should aim at minimizing time in captivity of wild animals to increase accuracy and ecological relevance of the scoring of plastic phenotypic traits.
|
|
| 5. |
- Zavorka, L., et al.
(author)
-
Linking omega-3 polyunsaturated fatty acids in natural diet with brain size of wild consumers
- 2022
-
In: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 199:4, s. 797-807
-
Journal article (peer-reviewed)abstract
- Omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) are key structural lipids and their dietary intake is essential for brain development of virtually all vertebrates. The importance of n-3 LC-PUFA has been demonstrated in clinical and laboratory studies, but little is known about how differences in the availability of n-3 LC-PUFA in natural prey influence brain development of wild consumers. Consumers foraging at the interface of aquatic and terrestrial food webs can differ substantially in their intake of n-3 LC-PUFA, which may lead to differences in brain development, yet this hypothesis remains to be tested. Here we use the previously demonstrated shift towards higher reliance on n-3 LC-PUFA deprived terrestrial prey of native brown trout Salmo trutta living in sympatry with invasive brook trout Salvelinus fontinalis to explore this hypothesis. We found that the content of n-3 LC-PUFA in muscle tissues of brown trout decreased with increasing consumption of n-3 LC-PUFA deprived terrestrial prey. Brain volume was positively related to the content of the n-3 LC-PUFA, docosahexaenoic acid, in muscle tissues of brown trout. Our study thus suggests that increased reliance on diets low in n-3 LC-PUFA, such as terrestrial subsidies, can have a significant negative impact on brain development of wild trout. Our findings provide the first evidence of how brains of wild vertebrate consumers response to scarcity of n-3 LC-PUFA content in natural prey.
|
|
| 6. |
- Lovén Wallerius, Magnus, et al.
(author)
-
Asymmetric competition over space use and territory between native brown trout (Salmo trutta) and invasive brook trout (Salvelinus fontinalis)
- 2022
-
In: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 100:4, s. 1033-1043
-
Journal article (peer-reviewed)abstract
- Interference competition over food and territory can shape population structure and habitat use within and between species. The introduction of invasive species often leads to novel competitive interactions over shared resources and invaders can eventually exclude the native species from preferred habitats. Invasive brook trout (Salvelinus fontinalis) introduced to northern Europe have excluded native brown trout (Salmo trutta) from numerous headwater streams. The fact that invasive brook trout can displace the more aggressive brown trout is puzzling. However, the earlier spawning and hatching of brook trout, compared to brown trout, may lead to unequal competition due to size advantage and prior resident status of brook trout at the fry stage. In this study, we examine the effect of competition between brown trout and brook trout using the natural size distribution of the two species. In two consecutive experiments, we first measured space use and feeding of a fry (age 0+) in the presence of a juvenile (age 1+). In experiment 2, we assessed territorial interactions between the species at the fry stage (age 0+) and if smaller brown trout could compensate the disadvantage by manipulating residence duration. Fry of brook trout feed sooner and spend more time close to the larger individual than brown trout fry. We also found that brook trout fry won most territorial contests against brown trout, and that increased residence duration led to longer and more aggressive interactions. The results suggest that smaller brown trout are displaced to suboptimal habitats in the presence of a larger brook trout. Therefore, the later emergence from gravel beds resulting in the naturally occurring size disadvantage of brown trout at the fry stage may lead to unequal territorial interactions that could explain why brown trout are displaced from preferred habitats in sympatry with brook trout. © 2022 The Authors. Journal of Fish Biology published by John Wiley & Sons Ltd on behalf of Fisheries Society of the British Isles.
|
|
| 7. |
- Zavorka, Libor, et al.
(author)
-
Demogenetic structure of brown trout Salmo trutta Linnaeus, 1758 populations in mountain headwaters: Implications for conservation management
- 2015
-
In: Journal of Applied Ichtyology. - : Hindawi Limited. - 0175-8659. ; 31:3, s. 501-508
-
Journal article (peer-reviewed)abstract
- A demogenetic analysis based on 7years of observation (2005-2011) was conducted to examine the population structure of brown trout Salmo trutta in pristine dendritic headwaters. The value of genetic divergence (FST) among sampling units ranged from -0.03 to 0.16. Demographic synchrony was low or moderate, and the average correlation coefficient of population growth between sampling units (r-) ranged from 0.28 to 0.66. No isolation by distance was observed, but genetic divergence was negatively correlated with demographic synchrony among sampling units. Variance in the population growth rate (i.e. local extinction probability) increased with distance from the mainstream and from other sampling units. In contradiction with the usual model of stream-dwelling salmonids, the upstream sections of headwaters holds only ephemeral subpopulations, whereas the mainstream played a role in the source area of the metapopulation. These findings stress the importance of the mainstream in management conservation for brown trout in low productive mountain headwaters. © 2015 Blackwell Verlag GmbH.
|
|
| 8. |
- Zavorka, L., et al.
(author)
-
Effect of individuals' local persistence, and spatial and temporal scale, on density-dependent growth: a study in brown trout Salmo trutta
- 2016
-
In: Ethology Ecology & Evolution. - : Informa UK Limited. - 0394-9370 .- 1828-7131. ; 28:3, s. 272-283
-
Journal article (peer-reviewed)abstract
- This study focuses on the mechanism of density-dependent growth in a stream-dwelling landlocked population of brown trout Salmo trutta. Specifically, body growth estimated by scale reading was examined in relation to population density and recapture rate (approximation of persistence of individuals within a location associated with dispersal and mortality) across 7 years and two spatial scales a reach and a whole stream. In concordance with previous studies, the whole-stream population density had a crucial effect on body growth in juveniles, but not in adult individuals. Furthermore, growth was negatively associated with the whole-stream population density in reaches with a low recapture rate, whereas no such relationship could be detected in reaches with a high recapture rate. Since persistence within a certain locality increases the familiarity of individuals with the habitat and with other conspecifics, we suggest that the negative effect of population density on growth might be relaxed in groups with a high recapture rate by positive influence of the familiarity both within the habitat but also towards other conspecifics, which decreases competition pressure.
|
|
| 9. |
- Zavorka, Libor, et al.
(author)
-
Within-stream phenotypic divergence in head shape of brown trout associated with invasive brook trout
- 2020
-
In: Biological Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4066 .- 1095-8312. ; 129:2, s. 347-355
-
Journal article (peer-reviewed)abstract
- Competition with a non-native species can lead to morphological changes in native organisms induced by phenotypic plasticity, and by selection against individuals that do not adjust their morphology to the novel selection pressure. The morphological changes in native organisms are often associated with rapid behavioural responses to competition with the invader. However, knowledge of the interaction between the behaviour and morphology of native organisms competing with a non-native species remains scarce. Here, we investigated the effect of competition with non-native brook trout Salvelinus fontinalis on head shape of native brown trout Salmo trutta in a stream system where changes in diet and territorial behaviour of sympatric brown trout have previously been demonstrated. We found that sympatric brown trout had smaller eyes, shorter lower jaws and more terminal mouth than allopatric conspecifics. These differences in head shape were highly repeatable over a period of 12 months. Apparent survival indicated that the selection on head shape of brown trout was weaker in the sympatric than in the allopatric stretch of the stream. The results suggest that these changes reinforce divergences of foraging strategies between the allopatric and sympatric brown trout, which can negatively affect their population dynamics and trophic function in the food-web.
|
|
