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1.
Alain Pasquet Emilie Realis‐Doyelle Pascal Fontaine Fabrice Teletchea 《Aquaculture Research》2019,50(7):1824-1833
This study investigated the influence of temperature (4, 8 and 12°C) on development and survival of brown trout (Salmo trutta) fry. The three aims of this study were: (a) to propose a typology of malformations; (b) to compare malformation types between live and dead fry and (c) to establish relationships between temperature and malformation occurrences. It was found 20 single malformations and 39 combinations of two or more malformations. Comparison between dead and live fry at different development stages (hatching, emergence and first food intake) showed that malformations of yolk sac were predominant at hatching and then decreased, while malformations of skeleton or multiple malformations were higher thereafter. All dead fry, and only 14% of live fry were malformed. Dead fry were mainly characterized by yolk sac malformations and multiple malformations whatever the temperature. Live fry showed a higher rate of skeleton malformations at 12°C, and the different types of malformations were equally represented at two other temperatures (4 and 8°C). To conclude, it is suggested that some malformations (yolk sac at hatching, yolk sac associated with skeleton malformations at emergence and skeleton at first food intake or combinations of malformations at all stages)might be lethal as they were founding dead fry and that temperature influences differently the occurrence of malformations. 相似文献
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Tatiana Colchen Pascal Fontaine Yannick Ledor Fabrice Teletchea Alain Pasquet 《Aquaculture Research》2019,50(3):915-924
Cannibalism has been described in 390 teleost fish species belonging to 104 families. In rearing conditions, intra‐cohort cannibalism is one of the major bottlenecks during the early life stages of pikeperch (Sander lucioperca). This study aims to describe precisely the occurrence and the onset of cannibalism of this species during the first two post‐hatching months. In a first step, the cannibalistic behaviour was analysed through observations in three experiments. In each experiment, the number of cannibalistic cases was similar. From 14 to 48 days post‐hatching (dph), more than 60 % of prey ingestions were realized by tail‐first, but after 48 dph, the number of prey ingestions by head‐first increased. In a second step, the behavioural sequence exhibited to attack and to capture a conspecific was analysed, taking into account the size ratio between the cannibal and its prey. The behavioural sequence to capture was always the same, similar to a predatory sequence and it seems that the cannibal chose its prey about 10 s before attacking. Moreover, prey choice by a cannibal was based more on the size ratio between the cannibal and its prey than the previous activity of the potential prey. These new results could lead to solutions to decrease cannibalism in pikeperch rearing. 相似文献
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Cao Jin-zhen Yu Li-li You Xiao-di Kamdem D. Pascal 《中国林学(英文版)》2007,9(4):239-245
In order to clarify the interaction between copper and wood substances in wood treated with copper containing water-borne wood preservatives, the dielectric constant ε′ and dielectric loss factor ε″ of untreated wood and wood treated with four concentration levels of copper-ethanolamine (Cu-EA) solutions were determined within a temperature range from –100 to 40°C and a frequency range from 100 to 1 MHz. Three dielectric relaxation processes were observed in the ε″ spectrum; among them R-I is based on the reorientation of methylol groups in the amorphous region of wood cell walls and R-II is related to wood extractives. R-III appeared in Cu-EA treated wood, and its magnitude decreases with the concentration of Cu-EA solutions used in this experiment. This relaxation process was considered to be based on the reorientation of copper-ethanolamine-wood complexes in wood cell walls. At low copper retention, the hydrogen in the complex can form hydrogen bonding with adjacent hydroxyl groups, which results in a strong bonding state between copper and wood; at high copper retention, the numerous copper-ethanolamine complexes not only hinder them from forming hydrogen bonding with adjacent wood molecules due to steric hindrance, but also weaken the interaction between wood molecules themselves, which corresponds to reducing ε″ values of both R-I and R-III processes. The results explain the fact of in-creasing copper leaching in wood treated with high concentration copper-based water-borne preservatives. 相似文献
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This work presents evidence from three different valuation studieson the influence of gender in the formation of forestry-relatedvalues. Previous studies examined gender differences withoutexplicitly considering their interaction with other explanatoryvariables. Three separate studies dealing with forest-relatedgoods and services, revealed statistically significant differencesin peoples' preferences, especially between older women andolder men, and older and younger women. In these studies, althoughthere was no overall difference in preferences attributableto gender, there were significant differences related to ageand income, in combination with gender. 相似文献
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In this study, the contact angles of four different reference liquids (including distilled water, diiodomethane, formadide
and glycerol) formed on the surfaces of wood, treated with chromated copper arsenate (CCA) and two other emerging copper-based
water-borne systems (commercial names: NW and NS) were measured with sessile drop method. Based on the contact angle data,
the surface energy was obtained from the acid-base approach. The total surface energy consisted of Lifshiz-van der Waals parameter
and acid-base parameter. Results showed that the NW and CCA treatments made the wood surface more hydrophobic while the NS
treatment had the reverse effect on the wood surface mainly owing to the increased penetration of earlywood. By using three
liquids, diiodomethane, formamide and distilled water, the total surface energy obtained for untreated earlywood, untreated
latewood, CCA-treated earlywood, CCA-treated latewood, NW-treated earlywood, NW-treated latewood, NS-treated earlywood and
NS-treated latewood were 43.1, 44.5, 43.4, 45.1, 49.4, 40.6, 46.0 and 40.9 mJ/m2, respectively. The surface energy of CCA-treated wood was almost the same as untreated wood. After NW and NS treatments,
the surface energy of both earlywood and latewood changed a little. However, the change was not so obvious as to draw any
further conclusion concerning the influence of NW and NS treatments on the surface energy of wood.
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Translated from Journal of Beijing Forestry University, 2006, 28(4): 1–4 [译自: 北京林业大学学报] 相似文献
10.
Wafo P Kamdem RS Ali Z Anjum S Begum A Oluyemisi OO Khan SN Ngadjui BT Etoa XF Choudhary MI 《Fitoterapia》2011,82(4):642-646
A new diterpenoid, 15-angeloyloxy-16,17-epoxy-19-kauronic acid (1), along with five known metabolites, 16-kauren-19-oic acid (2), 6′-hydroxy-2′,3′,4,4′-tetramethoxychalcone (3), isosakuranetin (4), acacetin (5), and kaempferide (6) was isolated from the organic extracts of the roots of Chromoleana odorata. Their structures were determined by spectroscopic evidences. The structures of 1 and 2 were further confirmed by single-crystal X-ray diffraction studies. Compound 2 exhibited significant α-glucosidase inhibitory and antibacterial activities against Escherichia coli and Bacillus subtilis. 相似文献