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| 2. |
- Brandt, JC, et al.
(författare)
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A Goddard High Resolution Spectrograph atlas of echelle observations of the HgMn star chi Lupi
- 1999
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Ingår i: The Astronomical Journal. - : American Astronomical Society. - 1538-3881 .- 0004-6256. ; 117:3, s. 1505-1548
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Tidskriftsartikel (refereegranskat)abstract
- Observations of the ultra-sharp-lined, chemically peculiar star chi Lupi taken by the Goddard High Resolution Spectrograph in echelle mode are presented. Thirty-six intervals of the spectral region between 1249 and 2688 Angstrom are covered with resolving powers in the range 75,000-93,000. Line identifications are provided, and the observed spectra are compared with synthetic spectra calculated using the SYNTHE program and associated line lists with changes to the line lists. The significance of these spectra for the chi Lupi Pathfinder Project and the closely related atomic physics effort is discussed in a companion paper.
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| 3. |
- Danilov, Roman, et al.
(författare)
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Influence of waste water from the paper industry and UV-B radiation on the photosynthetic efficiency of Euglena gracilis
- 1999
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Ingår i: Journal of Applied Phycology. - 0921-8971 .- 1573-5176. ; 11, s. 157-163
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Tidskriftsartikel (refereegranskat)abstract
- The green flagellate Euglena gracilis has been used as a model organism to elucidate the possible large-scale and short-term effects of waste substances from the pulp and paper industry on photosynthetic efficiency (PE). Different concentrations of waste substances before and after treatment in a cleaning system were studied. The uncleaned sample at concentrations up to 1:10 and the cleaned sample at concentrations up to 1:5 showed stimulating effects on the PE after 7 days of incubation compared to the control. The effects of waste substances on the PE of E. gracilis were also studied in combination with short-term studies (20 and 40 min) of ultraviolet-B radiation (UV-B, 280–320 nm). It was shown that increasing concentrations of the uncleaned sample had continuously stimulating effects on the PE and worked protectively against UV-B radiation. The cleaned sample exhibited no effects, or negative effects, on the PE of E. gracilis together with UV-B radiation compared to the experiments with only UV-B radiation. At the concentration 1:1 of the cleaned sample an increase in the PE was detected due to the high concentration of the coloured substances and a decrease in the UV-B penetration. PE revealed itself to be highly sensitive for detecting toxic effects on E. gracilis and is thus very promising for use in regular toxicity tests of waste water from pulp and paper industry.
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| 4. |
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| 5. |
- Ekelund, Nils, 1956-
(författare)
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Effects of protein synthesis inhibitors on photoinhibition by UV–B (280-320 nm) radiation in the flagellate Euglena gracilis
- 1996
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Ingår i: Scienta Marina. ; 60:1, s. 95-100
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Tidskriftsartikel (refereegranskat)abstract
- Irradiation of the flagellate Euglena gracilis by UV-B radiation resulted in inhibition of photosynthesis and motility. After 2 h of UV-B radiation (1.2 W m super(-2)) the rates of photosynthesis did not completely recover until after 24 h in visible light. After 24 h in darkness the rate of photosynthesis was lower but the recovery time in darkness after UV-B radiation was about the same as in the visible light. In the presence of lincomycin, inhibitor of chloroplast protein synthesis, therecovery of photoinhibition was totally blocked for up to 16 h recovery in visible light. However, after 24 h recovery in visible light together with lincomycin, photosynthesis was partially recovered but recovery in darkness together with lincomycindid not give any reparation at all of photosynthesis. The inhibition of motility had a slower recovery phase and had not fully recovered even after 72 h in visible light.
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| 6. |
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| 7. |
- Ghetti, R, et al.
(författare)
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Influence of cross-talk rejection procedures on two-neutron intensity interferometry.
- 1999
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 421:3, s. 542-551
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Tidskriftsartikel (refereegranskat)abstract
- This work investigates the effects of a cross-talk rejection procedure on the two-neutron correlation function. The rejection method relies only upon simple kinematic relations between the energy of the detected neutrons and can be applied to commonly used detector configurations. It is demonstrated that the comparison of a cross-talk corrected correlation function with the theory is meaningful as long as the cross-talk rejection procedure and the response of the detector filter are consistently incorporated into the theoretical calculations.
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| 8. |
- Krznaric, Drago, et al.
(författare)
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Minimum Spanning Trees in d Dimensions
- 1999
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Ingår i: Nordic Journal of Computing. - : Publishing Association Nordic Journal of Computing. ; 6:4, s. 446-461
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Tidskriftsartikel (refereegranskat)abstract
- It is shown that a minimum spanning tree of $n$ points in $R^d$ under any fixed $L_p$-metric, with $p=1,2,\ldots,\infty$, can be computed in optimal $O(T_d(n,n) )$ time in the algebraic computational tree model. $T_d(n,m)$ denotes the time to find a bichromatic closest pair between $n$ red points and $m$ blue points. The previous bound in the model was $O( T_d(n,n) \log n )$ and it was proved only for the $L_2$ (Euclidean) metric. Furthermore, for $d = 3$ it is shown that a minimum spanning tree can be found in $O(n \log n)$ time under the $L_1$ and $L_\infty$-metrics. This is optimal in the algebraic computation tree model. The previous bound was $O(n \log n \log \log n)$.
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| 9. |
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| 10. |
- Nielsen, Tom, 1956-, et al.
(författare)
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Impact of natural and artificial ultraviolet-B radiation on motility and growth rate of marine dinoflagellates
- 1995
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Ingår i: Journal of Photochemistry and Photobiology. B. - 1011-1344 .- 1873-2682. ; 27, s. 73-79
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Tidskriftsartikel (refereegranskat)abstract
- The growth rates and motility of dinoflagellates were studied in the field in the presence or absence of UVB radiation, as well as in the laboratory under artificial radiation conditions. Photosynthetically active radiation (PAR, 400–700 nm) and UVB radiation showed large variations due to cloud cover and seasonal changes in natural daylight. In Swedish coastal water, UVB radiation was attenuated to about 10% of surface irradiance at a depth of 120 cm. There was no significant difference in the motility of two strains of Prorocentrum minimum (Atlantic, LAC4LI; Kattegat, LAC6KA83) kept in the water at different depths (35 and 120 cm) for 4 h, with or without natural solar UV radiation, except for a day with high UVB irradiance (1.2 W m−2), which decreased the motility at a depth of 35 cm for the two species). Simulated in situ experiments with 2 h natural daylight, with and without natural UV radiation (UVB, 1.6 W m−2), had a dramatic effect on the motility of Gyrodinium aureolum. Artificial UVB radiation from UV lamps (4 h, 2.72 kJ m−2 day−1, biologically effective UVB radiation, UVBBE) in the laboratory decreased the motility of Heterocapsa triquetra (LAC20) by 56% and the two strains of P. minimum (Atlantic, LAC4LI; Kattegat, LAC6KA83) by 43% and 36% respectively; the growth was inhibited for all species, as well as for Amphidinium carterae (LAC1KA83), when organisms were exposed to more than 0.7 kJ m−2 day−1 of UVBBE radiation.
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