| 21. |
- Albertsson, Jan, 1959-, et al.
(författare)
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Deposit-feeding amphipods (Monoporeia affinis) reduce the recruitment of copepod nauplii from benthic resting eggs in the northern Baltic Sea
- 2001
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Ingår i: Marine Biology. - Umea Univ, Dept Ecol & Environm Sci, S-90187 Umea, Sweden. Umea Univ, Umea Marine Sci Ctr, S-90187 Umea, Sweden. : Springer Science and Business Media LLC. - 0025-3162 .- 1432-1793. ; 138:4, s. 793-801
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Tidskriftsartikel (refereegranskat)abstract
- We experimentally investigated the effect of different densities of the burrowing, deposit-feeding amphipod Monoporeia affinis on the recruitment of zooplankton from benthic resting eggs. Intact sediment cores with in situ density and species composition of zooplankton resting eggs and benthic fauna were collected in the northern Bothnian Sea, part of the Baltic Sea. We removed as many M, affinis as possible from the cores and then added different numbers of ill. affinis to the cores to generate a range of densities. The cores were exposed to different densities of M. affinis for either 3 or 40 days, after which the hatched zooplankton was registered. One subset of the cores were initially incubated under low temperature (2-3 degreesC, to prevent hatching) for 37 days (the resting phase), to allow for effects of M. affinis on unhatched resting eggs. These cores were then incubated under higher temperature (13 degreesC) for 3 days (the hatching phase), to induce hatching and allow for effects on hatching or hatched specimens. In a second subset of cores with the same time and temperature schedule, the M. affinis density was experimentally reduced at the start of the hatching phase, to evaluate the effect of M. affinis during the hatching phase. To a third subset of cores, we immediately initiated the hatching phase, without an experimental resting phase, to evaluate the effects induced during the resting phase. The most common zooplankton species that hatched was Eurytemora affinis (Copepoda), followed by Bosmina longispina maritima (Cladocera). In all cores that were subjected to a resting phase, the numbers of hatched E. affinis were log-linearly negatively related to density of M. affinis. An increase of M. affinis density from 1,000 to 5,000 individuals m(-2), normal field densities, reduced the hatching by 60-70%. The negative impact was mainly exerted during the hatching phase, suggesting predation on, burial of or physical injury of hatching nauplii or eggs in a late development stage as likely mechanisms. Also, the number of B. longispina maritima that hatched was reduced by M. affinis during the hatching phase, but no clear relation to density of M. affinis could be identified. The results show that M. affinis can reduce recruitment to zooplankton from benthic resting eggs. Such impact by the benthos on resting stages of zooplankton is therefore a potentially significant link between the benthic and pelagic systems.
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| 22. |
- Albertsson, Jan, 1959-, et al.
(författare)
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Impact of a borrowing deposit-feeder, Monoporeia affinis, on viable zooplankton resting eggs in the northern Baltic Sea
- 2000
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Ingår i: Marine Biology. - Umea Univ, Dept Ecol & Environm Sci, S-90187 Umea, Sweden. : Springer Science and Business Media LLC. - 0025-3162 .- 1432-1793. ; 136:4, s. 611-619
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the effect of different densities of the burrowing deposit-feeding amphipod Monoporeia affinis on the potential for recruitment of zooplankton from benthic resting eggs. Hatching of resting eggs was induced in the laboratory on sliced and resuspended 1-cm depth-sections of sediment cores, collected at six stations ill an archipelago area of the Gulf of Bothnia, Baltic Sea. The uppermost 5 cm of the sediment was studied. The most common species that hatched was Eurytemor affinis (Copepoda). Individuals from another copepod genus, Acartia, hatched in significant numbers only in the cores from two stations with low amphipod abundance. Cores from stations with high amphipod densities showed a deeper distribution of emerging E. affinis nauplii compared with stations with few amphipods: the oxidised sediment layer was also deeper at high M. affinis densities than at low. Total (0 to 5 cm strata pooled) number of hatched E. affinis nauplii was independent of amphipod density. This indicates that the effect of M. affinis on E. affinis eggs involves deeper burial due to bioturbation, rather than predation. Decreased benthic recruitment of zooplankton at localities with high M. affinis density is suggested, since more deeply positioned eggs are less likely to hatch. When hatching was induced in intact, non-sliced cores from one station, the number of E. affinis nauplii that hatched was on average 43% of the number that hatched in the upper centimetre of the sliced cores from the same station. This fraction (43%), if applied to the other stations, implied a potential for benthic recruitment of up to 80000 ind m(-2) for E. affinis. Due to its high abundance, M. affinis is likely to greatly reduce benthic recruitment of zooplankton in this system.
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| 23. |
- Albertsson, Per, 1964, et al.
(författare)
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Astatine-211 based radionuclide therapy: Current clinical trial landscape
- 2023
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Ingår i: Frontiers in Medicine. - : Frontiers Media SA. - 2296-858X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Astatine-211 (At-211) has physical properties that make it one of the top candidates for use as a radiation source for alpha particle-based radionuclide therapy, also referred to as targeted alpha therapy (TAT). Here, we summarize the main results of the completed clinical trials, further describe ongoing trials, and discuss future prospects.
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| 24. |
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| 25. |
- Aljetlawi, A A, et al.
(författare)
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Effect of food and sediment pre-treatment in experiments with a deposit-feeding amphipod, Monoporeia affinis
- 2000
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Ingår i: Journal of Experimental Marine Biology and Ecology. - Umea Univ, Dept Ecol & Environm Sci, SE-90187 Umea, Sweden.. - 0022-0981 .- 1879-1697. ; 249:2, s. 263-280
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Tidskriftsartikel (refereegranskat)abstract
- We experimentally investigated the effects of different pre-treatments of the sediment, and the effect of daily addition of fresh phytoplankton, on the growth and survival of 1-year-old (1 +) individuals of the deposit feeder Monoporeia affinis (Amphipoda). We used three different types of sieved sediment: pre-frozen muddy clay, non-pre-frozen muddy clay, and fine sand. The muddy clay contained phytoplankton originating from the surface sediment sampled in the field during the late spring bloom. No phytoplankton was initially present in sand. The experiment lasted for 18 days. M. affinis responded to the daily phytoplankton addition by increasing growth. Phytoplankton addition had no significant effects on the survival of M. affinis. Upon phytoplankton addition, the sandy and non-frozen muddy clay gave similar growth and survival responses. In contrast, the pre-frozen sediment resulted in significantly lower growth and survival. The growth was negative in all treatments without phytoplankton. Thus, the high initial chlorophyll content in the muddy clay was not of sufficient quality or concentration to allow a positive growth response in M. affinis. The growth of M. affinis was significantly correlated with the reduction of the chlorophyll. Our results indicated that M. affinis is capable of assimilating settled phytoplankton with no, or only a few days' time delay. (C) 2000 Elsevier Science BN: All rights reserved.
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| 26. |
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| 27. |
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| 28. |
- Barnes, A. T., et al.
(författare)
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LEGO - II. A 3mm molecular line study covering 100 pc of one of the most actively star-forming portions within the Milky Way disc
- 2020
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Ingår i: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 497:2, s. 1972-2001
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Tidskriftsartikel (refereegranskat)abstract
- The current generation of (sub)mm-telescopes has allowed molecular line emission to become a major tool for studying the physical, kinematic, and chemical properties of extragalactic systems, yet exploiting these observations requires a detailed understanding of where emission lines originate within the Milky Way. In this paper, we present 60'' (similar to 3pc) resolution observations of many 3mm-band molecular lines across a large map of the W49 massive star-forming region (similar to 100x100pc at 11kpc), which were taken as part of the 'LEGO' IRAM-30m large project. We find that the spatial extent or brightness of the molecular line transitions are not well correlated with their critical densities, highlighting abundance and optical depth must be considered when estimating line emission characteristics. We explore how the total emission and emission efficiency (i.e. line brightness per H-2 column density) of the line emission vary as a function of molecular hydrogen column density and dust temperature. We find that there is not a single region of this parameter space responsible for the brightest and most efficiently emitting gas for all species. For example, we find that the HCN transition shows high emission efficiency at high column density (10(22)cm(-2)) and moderate temperatures (35K), whilst e.g. N2H+ emits most efficiently towards lower temperatures (10(22)cm(-2); <20K). We determine XCO(1-0)similar to 0.3 x 10(20)cm(-2)(Kkms(-1))(-1), and alpha(HCN(1-0))similar to 30M(circle dot)(Kkms(-1)pc(2))(-1), which both differ significantly from the commonly adopted values. In all, these results suggest caution should be taken when interpreting molecular line emission.
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| 29. |
- Beltrand, Jacques, et al.
(författare)
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Post-Term Birth is Associated with Greater Risk of Obesity in Adolescent Males.
- 2012
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Ingår i: The Journal of pediatrics. - : Elsevier BV. - 1097-6833 .- 0022-3476. ; 160:5, s. 769-773
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To test the hypothesise that post-term birth (>42 weeks gestation) adversely affects longitudinal growth and weight gain throughout childhood. STUDY DESIGN: A total of 525 children (including 17 boys and 20 girls born post-term) were followed from birth to age 16 years. Weight and height were recorded prospectively throughout childhood, and respective velocities from birth to end of puberty were calculated using a mathematical model. RESULTS: At birth, post-term girls were slimmer than term girls (ponderal index, 27.7±2.6 kg/m(3) vs 26.3±2.8 kg/m(3); P<.05). At age 16 years, post-term boys were 11.8 kg heavier than term subjects (body mass index [BMI], 25.4±5.5 kg/m(2) vs 21.7±3.1 kg/m(2); P<.01). The rate of obesity was 29% in post-term boys and 7% in term boys (P<.01), and the combined rate of overweight and obesity was 47% in post-term boys and 13% in term boys (P<.01). Weight velocity, but not height velocity, was higher in post-term boys at age 1.5-7 years (P<.05) and again at age 11.5-16 years (P<.05). BMI was higher in post-term boys at age 3 years, with the difference increasing thereafter. BMI and growth were similar in post-term and term girls. CONCLUSION: In this post-term birth cohort, boys, but not girls, demonstrated accelerated weight gain during childhood, leading to greater risk of obesity in adolescence.
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| 30. |
- Bjarnason, R, et al.
(författare)
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Leptin levels are strongly correlated with those of GH-binding protein in prepubertal children.
- 1997
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Ingår i: European Journal of Endocrinology. - 0804-4643 .- 1479-683X. ; 137:1, s. 68-73
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Tidskriftsartikel (refereegranskat)abstract
- There was a highly significant correlation between serum levels of leptin and those of GHBP, except in children with GHD. The possibility that leptin could mediate the effects of body fat mass on GH sensitivity, therefore, merits further investigation.
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