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| 2. |
- Lindeberg, Tony, 1964-
(author)
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On the behaviour in scale-space of local extrema and blobs
- 1991
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In: Theory and Applications of Image Analysis. - : World Scientific. ; , s. 38-47, s. 8-17
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Book chapter (peer-reviewed)abstract
- We apply elementary techniques from real analysis and singularity theory to derive analytical results for the behaviour in scale-space of critical points and related entities. The main results of the treatment comprise: a description of the general nature of trajectories of critical points in scale-space. an estimation of the drift velocity of critical points and edges. an analysis of the qualitative behaviour of critical points in bifurcation situations. a classification of what types of blob bifurcations are possible.
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| 3. |
- Hansson, B. S., et al.
(author)
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Sex pheromone perception in male pine sawflies, Neodiprion sertifer (Hymenoptera; Diprionidae)
- 1991
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In: Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology. - 0340-7594. ; 168:5, s. 533-538
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Journal article (peer-reviewed)abstract
- Electroantennographic and single sensillum recordings were performed on male pine sawfly, Neodiprion sertifer, antennae. Responses to the sex pheromone component (2S, 3S, 7S)- 3,7-dimethyl-2-pentadecenyl (diprionyl) acetate (SSS:OAc), to the behavioral inhibitor (2S, 3R, 7R)-diprionyl acetate (SRR:OAc), to the six other enantiomers of diprionyl acetate, and to the biosynthetic precursor diprionol were recorded. Responses to trans-perillenal, a monoterpene identified in female gland extracts and to (2S, 3S, 7S)-diprionyl propionate (SSS:OPr), a field attractant for N. sertifer and some related sawfly species were also recorded. EAG recordings demonstrated a high antennal sensitivity to SSS:OAc and to SSS:OPr. A somewhat lower response was elicited by SRR:OAc. Single sensillum recordings revealed 8–12 different cells firing in each sensillum, corresponding to the number of cells observed in earlier morphological investigations. Out of these cells all, except one, responded to SSS:OAc and to SSS:OPr. No differences in the response to the two components could be observed. The largest amplitude cell in each sensillum was specifically tuned to the behavioral antagonist, SRR:OAc. The pheromone perception system encountered in male pine sawflies thus differs clearly from that observed in moths.
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| 4. |
- Wassgren, Ann Britt, et al.
(author)
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Pheromone related compounds in pupal and adult female pine sawflies, Neodiprion sertifer, of different age and in different parts of the body
- 1992
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In: Journal of Insect Physiology. - 0022-1910. ; 38:11, s. 885-893
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Journal article (peer-reviewed)abstract
- The pine sawfly pheromone precursor 3,7-dimethyl-2-pentadecanol (diprionol) was quantified by gas chromatography in different body parts of virgin female Neodiprion sertifer. About one-third of the total amount (approx. 10 ng per female) was found in each of head + thorax, abdominal segments 1-3, and the remaining abdomen. Diprionol was also found in the respective parts of pupae, but in lower amounts. This suggests that at least the final steps of the pheromone biosynthesis take place in many parts of the body, possibly in the cuticle. The diprionol content remained relatively constant over the whole lifetime of virgin females. By using coupled gas chromatography-electroantennogram detection three active compounds in the acetylated female extract were observed. These corresponded to the pheromone, (2S,3S,7S)-diprionyl acetate, and its homologues with the chain shortened by one and two carbons respectively, as determined by gas chromatography-mass spectrometry. In addition, the homologue having a chain elongated by one carbon was found. The homologues occurred in amounts of 2-5% of the diprionyl acetate. When synthetic homologues were tested in the field, alone or in combination with diprionyl acetate, they were not behaviourally active to male sawflies, despite their electroantennogram activity. A threo-isomer of diprionol, most likely (2S,3R,7R), was present in the females in amounts less than 0.5% of the (2S,3S,7S)-content. The acetate of this threo-isomer is known as both synergist and inhibitor to the (2S,3S,7S)-isomer. trans-Perillenal was found in the abdominal segments 1-3 of both males and females and its possible biosynthetic relationship to diprionol is discussed.
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| 5. |
- Back, C, et al.
(author)
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High-dosage treatment of a Quebec stream with Bacillus thuringiensis serovar. israelensis : efficacy against black fly larvae (Diptera, Simuliidae) and impact on nontarget insects
- 1985
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In: Canadian Entomologist. - 0008-347X .- 1918-3240. ; 117:12, s. 1523-1534
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Journal article (peer-reviewed)abstract
- A typical lake outlet of the Canadian Shield was treated for 15 min with a high dose (5.28 g/L s−1 of discharge) of Teknar®, a commercial formulation of Bacillus thuringiensis serovar. israelensis. Efficacy on Simuliidae larvae and impact on non-target aquatic insects of this stream were monitored using drift nets, counting plates, and artificial turf substrates along a 1000-m section downstream of the site of application. Compared with a 4-day pre-treatment average for 12-h sampling periods, drift of Simuliidae increased from 64 to 92 ×, with shorter peaks of 133–184 ×, 2–6 h after treatment. There was no evident drift increase in larvae of Ephemeroptera, Plecoptera, Trichoptera, Chironomidae, or dipterous pupae, but larvae of Blephariceridae (Diptera) were severely affected as their drift was increased by up to 50 × and remained high for 3 days. After 30 h the mortality of Simuliidae on counting plates ranged from 95 to 82% in the first 300 m, with detachment rates of 78.5–46.5%. Densities of non-target insect larvae were not reduced on the artificial substrates, except for 2 genera of Chironomidae (Eukiefferella and Polypedilum) which were reduced 26 to 39% of their original density. Drifting larvae of 1 chironomid genus (Phaenopsectra) also showed symptoms of toxemia by B.t.i. The main impact of the treatment was thus seen in 2 Nematocera families (Chironomidae and Blephariceridae) which were mainly exposed to B.t.i. sedimented on the bottom of the stream or attached to periphyton growing on rocks.
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| 7. |
- Andreasson, Maria, et al.
(author)
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TOXICITY OF BILE FROM FISH EXPOSED TO PCP-SPIKED SEDIMENT
- 1994
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In: AQUATIC TOXICOLOGY. - 0166-445X. ; 30:2, s. 171-182
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Journal article (peer-reviewed)abstract
- : In order to evaluate if toxicity of the bile may be used to establish lethal and sublethal exposure of fish to pollutants, rainbow trout (Oncorhynchus mykiss) were exposed to PCP-spiked sediment (4, 8, 16, 32 and 64 mg PCP/kg w.w.) for 1 or 2 days, sacrificed and their bile tested for toxicity to Daphnia magna. Exposure was monitored daily by Daphnia toxicity tests of sediment and water. The 24-h EC50s, expressed as mg PCP/kg sediment w.w., were 20 +/- 6.4 for sediment and 9.6 +/- 5.1 for water phase tests, respectively. The corresponding 24-h LC50 value for sediment to rainbow trout was ca 16 mg/kg w.w. Bile toxicity was tested directly and after hydrolysis by acid and by beta-glucuronidase. Bile and bile extract of surviving trout exposed to the median lethal concentration of sediment (16 mg PCP/kg w.w.) were 10 times more toxic than control fish. Hydrolyzed bile extract of fish exposed to 4 mg PCP/kg w.w. was 10-50 times more toxic than that of control fish. Thus, toxicity tests of extracts of hydrolyzed bile were more sensitive than toxicity tests based on water and sediment. Therefore, at least for chemicals which accumulate in the bile, toxicity tests of the bile may be used to establish sublethal exposure in fish.
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| 8. |
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| 9. |
- Berglind, Rune, 1952, et al.
(author)
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THE EFFECTS OF LEAD ON DELTA-AMINOLEVULINIC-ACID DEHYDRATASE ACTIVITY, GROWTH, HEMOGLOBIN CONTENT, AND REPRODUCTION IN DAPHNIA-MAGNA
- 1985
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In: ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY. - 0147-6513. ; 9:2, s. 216-229
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Journal article (peer-reviewed)abstract
- The effects of continuous exposure to lead for various periods and recovery in clean water on δ-aminolevulinic acid dehydratase (ALA-D) activity, hemoglobin content, growth, and reproduction were studied in Daphnia magna. Steady-state inhibition of ALA-D activity was reached within 2 days in 16, 64, and 256 μg Pb liter−1, but restoration in clean water was prolonged in relation to previous exposure. In spite of the inhibition of ALA-D activity hemoglobin content increased after 2 days in 16 and 24 μg Pb liter−1. Furthermore, hemoglobin content in previously exposed animals increased during recovery in clean water. Maximum hemoglobin content (2.9 times control value) was found after 2 days recovery of animals exposed to 64 μg Pb liter−1. These findings suggest that some enzyme(s) other than ALA-D in the biosynthetic pathway of hemoglobin formation is (are) more sensitive to lead. Growth, in contrast to reproduction, was stimulated by low concentrations of lead (<64 μg Pb liter−1), although in 256 μg Pb liter−1 growth was also significantly impaired. After 19 days the 16 and 50% reproductive impairment concentrations were ⩽1 and 10 μg Pb liter−1, respectively.
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| 10. |
- Dave, Göran, 1945, et al.
(author)
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PRECISION OF THE NITOCRA-SPINIPES ACUTE TOXICITY TEST AND THE EFFECT OF SALINITY ON TOXICITY OF THE REFERENCE TOXICANT POTASSIUM BICHROMATE
- 1993
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In: ENVIRONMENTAL TOXICOLOGY AND WATER QUALITY. - 1053-4725. ; 8:3, s. 271-277
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Journal article (peer-reviewed)abstract
- The precision of the 96-h LC50 test with the eurohaline copepod Nitocra spinipes was evaluated from a data set containing 85 tests with the reference toxicant potassium bichromate conducted at 12 laboratories during a 12-year period. The overall mean was 30 mg/L as K2Cr2O7 with a coefficient of variation (CV) of 47% (N = 85). Since salinity differed between tests (7-33 parts per thousand), it explained part of the variation (ca. 25%; Pearson two-tailed test r = 0.49; p = 0.0000; N = 85). The effect of salinity on Cr(VI) toxicity was confirmed in an experiment with 4 salinities (3.4, 6.8, 14.6, and 27 parts per thousand) and was explained to 99% by the equation 96-h LC50 (mg/L) = 2.58 + 1.79 x salinity (parts per thousand). Intralaboratory CVs for corresponding salinities ranged from 8 to 35% (repeatability). Interlaboratory CVs at two salinities were 42% (N = 11) at 7-9 parts per thousand and 47% (N = 4) at 15-16 parts per thousand.
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