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41.
Thong Pham Van Olivier Le Duc Benjamin Leprince Cedric Bordes Vinh Quang Luu Luca Luiselli 《水产资源保护:海洋与淡水生态系统》2020,30(1):183-193
- Rafetus swinhoei, a giant softshell turtle from southern China and northern Vietnam, is the rarest turtle species on Earth, and only two individuals are known worldwide (one in the wild). There is very little ecological information for this species, and the remnant distribution remains completely unknown.
- This article reports for the first time in the international literature the results of a structured questionnaire survey concerning the ecology and distribution of R. swinhoei in Vietnam. The standardized questionnaire consisted of 15 questions and was administered to 10 former Rafetus hunters with several years of experience in catching this species.
- There was considerable consensus among the hunters regarding several aspects of the biology of R. swinhoei, with special reference to its reproductive and feeding habits. The mean weight of 58 captured individuals was 53 kg, with the majority of individuals weighing 15–40 kg (median = 40 kg) and only 17.2% of individuals weighing more than 100 kg.
- Based on the hunters'answers, it was established that the population collapse of R. swinhoei in Vietnam occurred in two phases: first during the 1980s, when the population size dramatically decreased, and second, at the beginning of the 1990s, when many hunters simultaneously collected multiple individuals from populations already experiencing severe impacts. There was also a general agreement that these turtles became very rare after 1991–92.
- In total, 90% of the hunters agreed that there should still be wild R. swinhoei individuals at their respective sites, and some of the hunters also reported a few recent sightings that they attributed to the target species.
- As several sites of likely presence were identified, we suggest that extensive trapping should be planned at these sites in future.
42.
Olivier Le Duc Thong Pham Van Benjamin Leprince Cedric Bordes Anh Nguyen Tuan John Sebit Benansio Nic Pacini Vinh Quang Luu Luca Luiselli 《水产资源保护:海洋与淡水生态系统》2020,30(6):1074-1087
- Next to cetaceans and megafishes, freshwater turtles are the most iconic endangered freshwater species.
- A detailed questionnaire survey conducted with more than 100 individuals from fishing communities in northern Vietnam was used to investigate the current status of Southeast Asian turtles and provides new hope concerning the survival of Rafetus swinhoei, for which recent official records in the wild are limited to a single individual in Vietnam.
- The survey included the entire Vietnamese portion of the Da River in Hoa Binh and Son La provinces, as well as the Chu and Ma river system in Thanh Hoa Province, as they are the last sites where the world's rarest and largest Asian softshell turtle has been seen. The questionnaire, conducted in Vietnamese, focused on demographic details, fishing intensity and gear, the status of fishing grounds, and the frequency of interaction with turtles.
- The great majority of fishers could recognize different turtle species from photographs and describe their preferential breeding habitats; not all knew that they are protected. A few confirmed that more than once each year they still encounter freshwater turtles during their fishing activities.
- This survey provides detailed information on sites where freshwater turtles are still seen in northern Vietnam and broadens our hope that wild individuals of the extremely rare R. swinhoei may still be present in the remaining riparian wetlands of these biodiverse, dammed, and controlled river basins in North Vietnam.
43.
King-Casas B Tomlin D Anen C Camerer CF Quartz SR Montague PR 《Science (New York, N.Y.)》2005,308(5718):78-83
Using a multiround version of an economic exchange (trust game), we report that reciprocity expressed by one player strongly predicts future trust expressed by their partner-a behavioral finding mirrored by neural responses in the dorsal striatum. Here, analyses within and between brains revealed two signals-one encoded by response magnitude, and the other by response timing. Response magnitude correlated with the "intention to trust" on the next play of the game, and the peak of these "intention to trust" responses shifted its time of occurrence by 14 seconds as player reputations developed. This temporal transfer resembles a similar shift of reward prediction errors common to reinforcement learning models, but in the context of a social exchange. These data extend previous model-based functional magnetic resonance imaging studies into the social domain and broaden our view of the spectrum of functions implemented by the dorsal striatum. 相似文献
44.
Purification of a Low Molecular Weight Fucoidan for SPECT Molecular Imaging of Myocardial Infarction
Pierre Saboural Frédéric Chaubet Francois Rouzet Faisal Al-Shoukr Rana Ben Azzouna Nadia Bouchemal Luc Picton Liliane Louedec Murielle Maire Lydia Rolland Guy Potier Dominique Le Guludec Didier Letourneur Cédric Chauvierre 《Marine drugs》2014,12(9):4851-4867
Fucoidans constitute a large family of sulfated polysaccharides with several biochemical properties. A commercial fucoidan from brown algae, containing low molecular weight polysaccharidic species constituted of l-fucose, uronic acids and sulfate groups, was simply treated here with calcium acetate solution. This treatment led to a purified fraction with a yield of 45%. The physicochemical characterizations of the purified fucoidan using colorimetric assay, MALLS, dRI, FT-IR, NMR, exhibited molecular weight distributions and chemical profiles similar for both fucoidans whereas the sulfate and l-fucose contents increased by 16% and 71%, respectively. The biodistribution study in rat of both compounds labeled with 99mTc evidenced a predominant renal elimination of the purified fucoidan, but the crude fucoidan was mainly retained in liver and spleen. In rat myocardial ischemia-reperfusion, we then demonstrated the better efficiency of the purified fucoidan. This purified sulfated polysaccharide appears promising for the development of molecular imaging in acute coronary syndrome. 相似文献
45.
Cano-López M Pardo-Mínguez F Schmauch G Saucier C Teissedre PL López-Roca JM Gómez-Plaza E 《Journal of agricultural and food chemistry》2008,56(14):5932-5941
Several factors may affect the results obtained when micro-oxygenation is applied to red wines, the most important being the moment of application, the doses of oxygen, and the wine phenolic characteristics. In this study, three red wines, made from Vitis vinifera var. Monastrell (2005 vintage) and with different phenolic characteristics, were micro-oxygenated to determine as to how this technique affected the formation of new pigments in the wines and their chromatic characteristics. The results indicated that the different wines were differently affected by micro-oxygenation. In general, the micro-oxygenated wines had a higher percentage of new anthocyanin-derived pigments, being that this formation is more favored in the wines with the highest total phenol content. These compounds, in turn, significantly increased the wine color intensity. The wine with the lowest phenolic content was less influenced by micro-oxygenation, and the observed evolution in the degree of polymerization of tannins suggested that it might have suffered overoxygenation. 相似文献
46.
Barnabas Neba Nfornkah Louis Zapfack Martin Tchamba Cedric Djomo Chimi Bonaventure Sonke 《Journal of Sustainable Forestry》2018,37(6):619-631
Vascular epiphyte biomass is poorly studied in Congo Basin forest. The aim of this study was to develop a protocol to estimate epiphyte biomass. Epiphytes were collected on 77 phorophytes of diameter 57–169.5 cm, oven-dried for biomass. Allometric equations for epiphyte biomass were developed with diameter and phorophyte height as predictor variables using regression analysis. The mean epiphyte biomass was 24.48 kg/phorophyte with a standard deviation of ±49.99. Cylicodiscus gabunensis and Triplochiton scleroxylon hosted the greatest epiphyte biomass with a mean vascular epiphyte biomass of 71.65 and 62.3 kg/phorophyte, respectively. Kruskal–Wallis test (p = 0.005) showed that there was a significant difference between epiphyte biomass with respect to phorophyte species. The relationship found between epiphyte biomass and dendrometric variables of the phorophytes were intermediate (Adj.R2 < 0.630) meaning epiphyte biomass increased with increasing tree diameter. However, models with diameter input variables had greater prediction than input variables of total height. Based on the Akaike Information Criterion (AIC), the allometry lnY = ?21.37 + 5.21 x ln(D) ?0.35 x ln(H) with AIC (183) was the best equation for the prediction of epiphyte biomass. These findings shall contribute to REDD+ (Reducing Emissions from Deforestation and Forest Degradation) strategy for climate change mitigation in Congo Basin. 相似文献
47.
We report on the in situ synthesis and stabilization of manganese dioxide (MnO2) onto four different silk yarns (mulberry, tasar, muga and eri silks). A new ultrasound-assisted procedure was used to reduce permanganate (MnO4 ?) and yielded MnO2 nanoparticles (NPs) on/in the different silk fibers. Using a factorial design we assessed the influence of the silk type, manganese precursor concentration, sonication time, and temperature. The results indicated no measurable effect of the process parameters on the silk structures, but significant correlation with the rate of degradation of methylene blue (MB) and the fraction of permanganate consumed. Further optimization of the factorial model identified the optimal process conditions for each silks: mulberry (150 min sonication, 20 mM permanganate), eri (360 min, 10 mM), tasar (150 min, 10 mM) and Muga (20 min, 10 mM). The operational stability (successive catalysis) of the optimum hybrids showed good performance over 5 cycles and most importantly reduced direct dye absorption relatively to dye oxidation. Overall, we found that all silks could template the formation and stabilization of different MnO2 polymorphs and yielded catalytic instead of stoichiometric hybrid fibers. 相似文献
48.
Low feed consumption has been suggested as a major impediment for the development of effective formulated diets for spiny lobsters. To seek an explanation for the low feed consumption, this study compared the feed consumption, appetite revival, foregut evacuation and fecal production of different sizes of spiny lobster Jasus edwardsii juveniles fed a fresh natural diet (i.e. mussel flesh) and a dry formulated diet. In addition, the effect of feeding frequency was determined by feeding juvenile lobsters the same ration of formulated diet at different time intervals. i.e., same ration delivered 3 week− 1, 1 day− 1, 2 day− 1, 5 day− 1 and 5 night− 1. Lobster (10–15 g) growth and feed consumption (1.15% BW day− 1) was maximized when receiving a single ration daily of the formulated diet. A slow appetite revival (AR > 18 h) on the formulated diet was consistent with the negative effect of increasing feeding frequency on growth and consumption. In addition, there appeared to be no major advantage in dry matter intake by providing the nutrient dense dry formulated diet to Jasus edwardsii. Lobsters fed fresh mussel flesh (79.8% moisture) consumed similar levels of dry matter as those lobsters fed the dry formulated feed (7.3% moisture). This appears to be due to high moisture gain and expansion of the dry feed in the lobster foregut. Foregut evacuation lasted 10 h for the two diets but a delay in initial foregut evacuation and processing of the formulated diet was evident, and may have negatively affected feed consumption, appetite revival and dry matter digestibility (61.2%) of the dry formulated diet compared to the mussel flesh diet (89.2%). Appetite revival on mussel flesh was almost complete by 12 h after a satiation ration and was governed primarily by the rate of foregut evacuation. Differences in the timing of foregut evacuation and fecal production between the two diets suggested that a greater proportion of the formulated diet entered the midgut directly.The results indicate that J. edwardsii cannot achieve high levels of feed consumption on formulated diets because gut throughput is reduced due to a small foregut capacity, expansion of the feed post-ingestion, lengthy foregut filling time (1–2 h) and clearance time (10 h), combined with slow gut throughput time (34–42 h) and appetite revival (> 18 h). A slow appetite revival and difficulties in processing and digestion of formulated diets appear as major issues to be resolved to improve the performance of formulated diets required for the commercial aquaculture of J. edwardsii and possibly other spiny lobsters. 相似文献