Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Persson Anders) "

Sökning: WFRF:(Persson Anders)

Sortera/gruppera träfflistan
  • Hansson, Lars-Anders, et al. (författare)
  • Food-chain length alters community responses to global change in aquatic systems
  • 2013
  • Ingår i: Nature Climate Change. - Nature Publishing Group. - 1758-678X. ; 3:3, s. 228-233
  • Tidskriftsartikel (refereegranskat)abstract
    • Synergies between large-scale environmental changes, such as climate change(1) and increased humic content (brownification)(2), will have a considerable impact on future aquatic ecosystems. On the basis of modelling, monitoring and experimental data, we demonstrate that community responses to global change are determined by food-chain length and that the top trophic level, and every second level below, will benefit from climate change, whereas the levels in between will suffer. Hence, phytoplankton, and thereby algal blooms, will benefit from climate change in three-, but not in two-trophic-level systems. Moreover, we show that both phytoplankton (resource) and zooplankton (consumer) advance their spring peak abundances similarly in response to a 3 degrees C temperature increase; that is, there is no support for a consumer/resource mismatch in a future climate scenario. However, in contrast to other taxa, cyanobacteria-known as toxin-producing nuisance phytoplankton(3)-benefit from a higher temperature and humic content irrespective of the food-chain composition. Our results are mirrored in natural ecosystems. By mechanistically merging present food-chain theory with large-scale environmental and climate changes, we provide a powerful framework for predicting and understanding future aquatic ecosystems and their provision of ecosystem services and water resources.
  • Gjörloff Wingren, Anette, et al. (författare)
  • Protein expression and cellular localization in two prognostic subgroups of diffuse large B-cell lymphoma:
  • 2007
  • Ingår i: Leukemia Lymphoma;11. - InformaWorld. - 1042-8194. ; :11
  • Tidskriftsartikel (refereegranskat)abstract
    • Patients diagnosed with diffuse large B-cell lymphoma (DLBCL) show varying responses to conventional therapy, and this might be contributed to the differentiation stage of the tumor B-cells. The aim of the current study was to evaluate a panel of kinases (ZAP70, PKC-beta I and II and phosphorylated PKB/Akt) and phosphatases (PTEN, SHP1 and SHP2) known to be frequently deregulated in lymphoid malignancies. De novo DLBCL cases were divided into two subgroups, the germinal center (GC) group (14/28) and the non-germinal center (non-GC) or activated B-cell (ABC) group (14/28). ZAP70 and PKC-beta II were expressed in a significantly higher percentage of tumor cells in the clinically more aggressive non-GC group compared with the prognostically favourable GC group. Also, the subcellular localization of PKC-beta I and II differed in DLBCL cells, with the PKC-beta I isoform being expressed in both the cytoplasm and nucleus, while PKC-beta II was found exclusively in the cytoplasm. Loss of nuclear PTEN correlated with poor survival in cases from both subgroups. In addition, five cell lines of DLBCL origin were analyzed for protein expression and for mRNA levels of PTEN and SHP1. For the first time, we show that ZAP70 is expressed in a higher percentage of tumor cells in the aggressive non-GC subgroup of DLBCL and that PKC-beta I and II are differently distributed in the two prognostic subgroups of de novo DLBCL.
  • Hansson, Lars-Anders, et al. (författare)
  • Consumption patterns, complexity and enrichment in aquatic food chains
  • 1998
  • Ingår i: Proceedings of the Royal Society, London, B. - Royal Society Publishing. - 1471-2954 (Online) .- 0962-8452 (Print). ; 265:1399, s. 901-906
  • Tidskriftsartikel (refereegranskat)abstract
    • The interactions between consumers and prey, and their impact on biomass distribution among trophic levels, are central issues in both empirical and theoretical ecology. In a long-term experiment, where all organisms, including the top predator, were allowed to respond to environmental conditions by reproduction, we tested predictions from `prey-dependent' and `ratio-dependent' models. Prey-dependent models made correct predictions only in the presence of strong interactors in simple food chains, but failed to predict patterns in more complex situations. Processes such as omnivory, consumer excretion, and unsuitable prey-size windows (invulnerable prey) increased the complexity and created patterns resembling ratio-dependent consumption. However, whereas the prey-dependent patterns were created by the mechanisms predicted by the model, ratio-dependent patterns were not, suggesting that they may be right for the wrong reason'. We show here that despite the enormous complexity of ecosystems, it is possible to identify and disentangle mechanisms responsible for observed patterns in community structure, as well as in biomass development of organisms ranging in size from bacteria to fish.
  • Lindegren, Martin, et al. (författare)
  • Towards sustainable fisheries of the Oresund cod (Gadus morhua) through sub-stock-specific assessment and management recommendations
  • 2013
  • Ingår i: ICES Journal of Marine Science. - Oxford Univ. Press. - 1054-3139. ; 70:6, s. 1140-1150
  • Tidskriftsartikel (refereegranskat)abstract
    • Fisheries management traditionally relies on stock assessments assuming discrete populations within large administrational areas. However, failing to account for sub-stock structuring may result in overestimation of the stocks' true harvest potential and unsustainable exploitation of small stock elements. Atlantic cod (Gadus morhua) frequently occurs in spatially segregated populations, some of which exhibit fine-scaled stock structuring within current management boundaries. Here we use the locally spawning cod stock in the Sound ("Oresund") as a case study, and perform a sub-stock-specific assessment to evaluate biological and economic effects of managing the Sound cod as a separate stock. Our results indicate that reducing exploitation pressure, particularly through technical regulations i. e. increasing gill-net mesh sizes, would not only enhance the stock age distribution, but yield long-term net benefits to the local gill-net fishery. Furthermore, our study emphasizes the need for developing sub-stock-specific management recommendations in order to ensure the maintenance of fisheries resources in general, and the persistence of sub-stock structuring in particular.
  • Ljungberg, Peter, 1976-, et al. (författare)
  • Effects of small-scale habitat fragmentation on predator–prey interactions in a temperate sea grass system
  • 2013
  • Ingår i: Marine Biology. - 0025-3162. ; 160:3, s. 667-675
  • Tidskriftsartikel (refereegranskat)abstract
    • During the last decades, fragmentation has become an important issue in ecological research. Habitat fragmentation operates on spatial scales ranging over several magnitudes from patches to landscapes. We focus on small-scale fragmentation effects relevant to animal foraging decision making that could ultimately generate distribution patterns. In a controlled experimental environment, we tested small-scale fragmentation effects in artificial sea grass on the feeding behaviour of juvenile cod (Gadus morhua). Moreover, we examined the influence of fragmentation on the distribution of one of the juvenile cod’s main prey resources, the grass shrimp (Palaemon elegans), in association with three levels of risk provided by cod (no cod, cod chemical cues and actively foraging cod). Time spent by cod within sea grass was lower in fragmented landscapes, but total shrimp consumption was not affected. Shrimp utilised vegetation to a greater extent in fragmented treatments in combination with active predation. We suggest that shrimp choose between sand and vegetation habitats to minimize risk of predation according to cod habitat-specific foraging capacities, while cod aim to maximize prey-dependent foraging rates, generating a habitat-choice game between predator and prey. Moreover, aggregating behaviour in grass shrimp was only found in treatments with active predation. Hence, we argue that both aggregation and vegetation use are anti-predator defence strategies applied by shrimp. We therefore stress the importance of considering small-scale behavioural mechanisms when evaluating consequences from habitat fragmentation on trophic processes in coastal environments.
  • Ljungberg, Peter, et al. (författare)
  • Prey selectivity by juvenile Atlantic cod Gadus morhua in three coastal habitat types
  • 2012
  • Ingår i: Marine Ecology: Progress Series. - Inter-Research. - 0171-8630. ; 466, s. 215-223
  • Tidskriftsartikel (refereegranskat)abstract
    • Coastal habitats are heavily subjected to eutrophication and commercial fisheries, and such alterations can affect organism interaction strengths and potentially influence trophic dynamics. A key species inhabiting coastal environments in temperate waters is the Atlantic cod Gadus morhua, which utilises coastal areas for food and shelter. We used an experimental mechanistic approach to assay prey selectivity by juvenile cod when foraging on grass shrimp Palaemon elegans and brown shrimp Crangon crangon, under light and dark conditions, in 3 of the most abundant habitat types in temperate coastal environments-sand, eelgrass (artificial vegetation mimicking Zostera marina), and bladderwrack Fucus vesiculosus. Using functional response relationships from single-prey experiments, we calculated the energetically best foraging strategy for cod in the 3 habitats, i.e. feeding selectively on either of the shrimp species or on a combination of both. These predictions were tested in experiments where the cod predator was offered both prey species. Cod selected both prey species in accordance with our predictions in eelgrass and in bladderwrack under light conditions, but a lower than predicted consumption of grass shrimp was found in sand and in bladderwrack under dark conditions. Cod decreasingly selected grass shrimp with increasing habitat complexity, i.e. the highest selectivity was in sand and the lowest selectivity was in bladderwrack. As the 2 shrimp species have different trophic roles, cod selective predation may have effects on lower trophic levels. We provide a quantitative prediction of cod selective predation in habitat types that undergo degradation, and suggest that such predation can influence the trophic consequences from environmental change.
  • Persson, Anders, et al. (författare)
  • Effects of enrichment on simple aquatic food webs
  • 2001
  • Ingår i: American Naturalist. - University of Chicago Press. - 0003-0147. ; 157:6, s. 654-669
  • Tidskriftsartikel (refereegranskat)abstract
    • Simple models, based on Lotka-Volterra types of interactions between predator and prey, predict that enrichment will have a destabilizing effect on populations and that equilibrium population densities will change at the top trophic level and every second level below. We experimentally tested these predictions in three aquatic food web configurations subjected to either high or low nutrient additions. The results were structured by viewing the systems as either food chains or webs and showed that trophic level biomass increased with enrichment, which contradicts food chain theory. However, within each trophic level, food web configuration affected the extent to which different functional groups responded to enrichment. By dividing trophic levels into functional groups, based on vulnerability to consumption, we were able to identify significant effects that were obscured when systems were viewed as food chains. The results support the prediction that invulnerable prey may stabilize trophic-level dynamics by replacing other, more vulnerable prey. Furthermore, the vulnerable prey, such as Daphnia and edible algae, responded as predicted by the paradox of enrichment hypothesis; that is, variability in population density increased with enrichment. Hence, by describing ecosystems as a matrix of food web interactions, and by recognizing the interplay between interspecific competition and predation, a more complete description of the ecosystem function was obtained compared to when species were placed into distinct trophic levels.
Skapa referenser, mejla, bekava och länka
fritt online (308)
Typ av publikation
tidskriftsartikel (525)
konferensbidrag (237)
bokkapitel (76)
annan publikation (73)
rapport (69)
recension (45)
visa fler...
bok (30)
doktorsavhandling (13)
samlingsverk (redaktörskap) (9)
forskningsöversikt (8)
licentiatavhandling (6)
proceedings (redaktörskap) (1)
visa färre...
Typ av innehåll
refereegranskat (676)
övrigt vetenskapligt (317)
populärvet., debatt m.m. (99)
Persson, Anders (471)
Persson, Anders, 195 ... (83)
Wahlström, Claes-Gör ... (52)
Svanberg, Sune (25)
Lundh, Olle (25)
Persson, Anders, 195 ... (23)
visa fler...
Andersson, Gunnar (19)
Thornell, Greger, (18)
Lindau, Filip (17)
Nilsson, Anders, (16)
Bjartell, Anders (15)
Johansson, Roger, (15)
Persson, Henry (15)
Persson, Per, (14)
L'Huillier, Anne (14)
Ynnerman, Anders, (14)
Persson, Anders I., ... (13)
Persson, Kent (12)
Brönmark, Christer (12)
Johannisson, Anders, (12)
Persson, Jenny L (12)
Dahlström, Nils, 196 ... (12)
Lönnermark, Anders, ... (11)
Genoud, Guillaume (11)
Persson Waller, Kari ... (11)
Persson, Anders, 197 ... (11)
Smedby, Örjan, (10)
Smedby, Örjan, 1956- ... (10)
Larsson, Jörgen (10)
Burza, Matthias (10)
Persson, Kenneth (10)
Nguyen, Hugo, (10)
Jackowski, Christian ... (10)
Persson, Bengt, (9)
Olofsson, Anders, (9)
Hansson, Lars-Anders (9)
Persson, Fredrik (9)
Eriksson, Peter S, 1 ... (9)
Blomqvist, Per (9)
Persson, Kristian, (9)
Lindsjö, Anders, (9)
Lindhagen-Persson, M ... (9)
Persson, Anders J, (9)
Quick, Petter, (9)
Welin, Stellan (9)
Persson, Anders, 198 ... (9)
Persson, Lars-Erik, (8)
Eriksson, Anders (8)
Ottosson, Tony, 1969 ... (8)
Svensson, Kerstin (8)
visa färre...
Lunds universitet (496)
Linköpings universitet (205)
Uppsala universitet (107)
Göteborgs universitet (62)
Sveriges Lantbruksuniversitet (58)
Chalmers tekniska högskola (53)
visa fler...
Umeå universitet (47)
Kungliga Tekniska Högskolan (38)
Luleå tekniska universitet (33)
Högskolan i Halmstad (28)
Karolinska Institutet (25)
Linnéuniversitetet (15)
Mälardalens högskola (15)
Stockholms universitet (12)
Örebro universitet (12)
Mittuniversitetet (12)
Karlstads universitet (11)
Södertörns högskola (7)
Malmö högskola (7)
Högskolan Kristianstad (6)
Högskolan i Skövde (6)
Högskolan i Borås (5)
Blekinge Tekniska Högskola (3)
Naturvårdsverket (2)
Högskolan i Jönköping (1)
Högskolan i Gävle (1)
Högskolan Dalarna (1)
Högskolan Väst (1)
visa färre...
Engelska (754)
Svenska (300)
Odefinierat språk (7)
Danska (4)
Norska (2)
Franska (1)
Ämne (HSV)
Teknik (30)
Naturvetenskap (27)
Medicin och hälsovetenskap (27)
Samhällsvetenskap (10)


pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy