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- 1. This paper reports on the dynamics of the coral community structure at A Ma Wan (AMW) and A Ye Wan (AYW) in Tung Ping Chau, Hong Kong, focusing on data collected before and after the summer typhoon seasons in 1997 to 1999. This period (1999) experienced the highest frequency of severe tropical cyclones to hit Hong Kong with one cyclone being the strongest to hit in the last 23 years (1984 to 2006).
- 2. This is part of a long‐term monitoring programme of subtropical coral communities that has been set up in AMW since May 1997 and AYW since May 1998 with nine fixed position 40 m long transects and 0.5 m × 0.5 m permanent quadrats laid at 5 m intervals along each transect. A total of 45 scleractinian coral species from 21 genera (12 families) was recorded, with 40 species in AMW and 32 species in AYW recorded at the beginning of the study.
- 3. Multidimensional scaling ordinations showed distinct spatial variations in the coral communities within and between sites. These variations were probably a result of the differential effects of the repeated cyclone impacts on the communities. Cyphastrea serailia, Goniopora lobata, Montipora peltiformis and Pavona decussata were the dominant species most strongly affected by cyclone impacts at AMW, experiencing a 6.2–16.2% loss of mean area cover during the study period. Some dominant species (e.g. P. decussata) in AYW also experienced a 6.5–14.3% loss of mean area cover within the same period.
- 4. Overall, these coral community structures appeared relatively stable and resistant to repeated physical disturbances. However, they may have low resilience towards more severe disturbances in the future. Preserving the resilience of coral communities/species in Tung Ping Chau should be one of the main goals of coral conservation strategies for the island.
2.
Analysis for the prospe ct of mu tton sheep production its potentiali ties of market based on the present s tate of mutton sheep production fully investigatio n about pres ent state developing trend of mutton sheep
production. Put forward the measure the suggesti on about establish productive system
of mutton sheep in Jilin province 《吉林农业大学学报》2000,22(1):87-90
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以香菇(Lentinus edodes)锁状联合发育时期的双核菌丝为材料,通过对不同酶组合处理降解细胞壁的效果比较和电镜观察,对双核菌丝细胞壁作了研究,获得以下结果;①香菇双核时期的菌丝细胞壁的化学组成推断主要是为1,3和1,4糖苷键连接的多糖类;②双核菌丝细胞壁宽厚,分层明显,壁物质沉积不均匀.沉积物主要呈颗粒状与短纤丝状,直接沉积在质膜上形成厚壁内层;③在双核菌丝顶端与倒壁凹陷处,以及菌丝交界处的细胞壁附近,都观察到管状、囊泡状的细胞器集合体.管状或囊泡状细胞器的一端,囊泡常与细胞壁内侧质膜相联.这一现象表明,香菇双核时期菌丝细胞的合成是十分活跃的. 相似文献
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The effect of the addition of marine algae in fish feed on the levels of bromophenols in fish flesh was studied. These bromophenols include 2-bromophenol, 4-bromophenol, 2,4-dibromophenol, 2,6-dibromophenol, and 2,4,6-tribromophenol. Two types of algae-containing fish feeds with 30% Padina arborescens and 30% Sargassum siliquastrum were developed. The total bromophenol contents of these feeds were 132 and 340 ng/g respectively, which were significantly higher than that of the control feed (8.9 ng/g) (ANOVA, p < 0.05). Silver seabream was used as the model fish for the feeding experiment. Bromophenol contents of both fish gut and flesh were monitored at 2-week intervals throughout the 8-week period. Two-way ANOVA showed that only the 30% S. siliquastrum-containing feed significantly (p < 0.05) increased the total bromophenol content in the fish flesh with time. This also produced sensorial differences in the fish flesh. 相似文献
6.
Veerle Mommaerts Kurt Put Jessica Vandeven Kris Jans Guido Sterk Lucien Hoffmann Guy Smagghe 《Pest management science》2010,66(11):1199-1207
BACKGROUND: To date, in modern agriculture, biological control strategies are increasingly becoming the preferred pest management approach. However, the success of microbiological control agents (MCAs) largely depends on efficient dissemination into the crop. The pollinator‐and‐vector technology employs pollinating insects like bees for a better dissemination. In this study, a new dispenser for bumblebee workers of Bombus terrestris L. was developed. Binab‐T‐vector and Prestop‐Mix were used as two typical MCA products for dissemination. RESULTS: In a first series of experiments in the laboratory for optimisation, the newly developed dispenser was a two‐way type dispenser, 20 cm long, with two rectangular compartments and different entrance and exit holes. In addition, the amounts of MCA loaded on the workers were 10 times higher with the new dispenser as compared with the side‐by‐side passageway (SSP) dispenser. Typically, the highest amounts were recovered from the thorax and legs of the workers. In a second series of experiments under greenhouse conditions with the use of queen‐right B. terrestris hives, successful dissemination in strawberry flowers was obtained at different distances from the hive (0–8 m, 8–18 m and 18–21 m), and the workers inoculated the first, second and third flowers that were consecutively visited. In addition, the new dispenser caused no adverse effects on worker foraging intensity, whereas a dramatic reduction was scored with an SSP dispenser. Finally, the data suggested that it is necessary to refill the newly developed dispenser at 3 day intervals. CONCLUSIONS: The results demonstrated that, with the use of the newly developed dispenser, bumblebee workers carried high amounts of MCA, and this resulted in a successful dissemination of MCA into strawberry flowers. Copyright © 2010 Society of Chemical Industry 相似文献
7.
Laurence J. McCook Jiansheng Lian Xinming Lei Zhu Chen Guifang Xue Put Ang Xiong Zhang Hui Huang 《水产资源保护:海洋与淡水生态系统》2019,29(Z2):33-43
- ensuring that marine systems are not overwhelmed within the new national jurisdiction, and maintaining and enhancing marine capacity;
- increased resourcing, supported by comprehensive and systematic economic valuations of ecosystem goods and services and natural capital;
- upgraded enforcement of existing environmental laws and regulations, combined with further refinement and development, especially around cumulative impact management;
- a particular focus on major reduction in water pollution in all forms;
- integration of marine management between Hong Kong SAR and surrounding Guangdong Province; and
- enhanced community engagement, participation and education.
- Finally, much greater, collaborative engagement by the international community with Chinese marine management and conservation would bring major, and very mutual, benefits.
8.
BACKGROUND: Entomovectoring as a plant protection strategy demands the design of an appropriate bioassay to assess the risks of potential side effects of the powder formulations in the dispenser towards the vectoring insect. This study reports on the development of a laboratory miniature‐dispenser‐based bioassay. This bioassay system was used to investigate the compatibility of five model products, Prestop‐Mix, Signum, kaolin, wheat flour and cellulose, with the bumblebee, Bombus terrestris L. RESULTS: The laboratory one‐way miniature‐dispenser bioassay showed that the fungicides and the carrier/diluent kaolin caused a worker mortality of > 70% after 5 weeks of exposure, while worker loss with wheat flour and cellulose was no higher than in the blank control (i.e. empty miniature dispenser) (<25%). The laboratory two‐way miniature‐dispenser bioassay comprised separated passageways and demonstrated that only kaolin was toxic (89 ± 11%). These results were also confirmed in a flight‐cage experiment. In addition, a negative effect was observed against reproduction/colony development when nests were exposed to kaolin (P < 0.05) in the two‐way miniature‐dispenser and flight‐cage bioassays. CONCLUSIONS: In the context of entomovectoring technology, the developed laboratory two‐way miniature‐dispenser bioassay gives a reliable prediction of the hazards associated with powder products. Additionally, the present data indicate the possibility of using cellulose and kaolin as respective negative and positive control carriers/diluents in future risk assessment experiments. Overall, the results show that, apart from kaolin, the tested fungicides and carriers/diluents are safe to be used with B. terrestris. Copyright © 2011 Society of Chemical Industry 相似文献
9.
A continuum failure criterion applicable to wood 总被引：1，自引：0，他引：1
Tom A.C.M. van der Put 《Journal of Wood Science》2009,55(5):315-322
The failure criterion is an essential part of all strength calculations of design. It was shown in the past that the tensor-polynomial
equation could be regarded as a polynomial expansion of the real failure surface. Now it is shown that the third-degree polynomial
is identical to the real failure criterion. It is also shown that the second-degree part of the polynomial is identical to
the orthotropic extension of the von Mises criterion for initial yield. The third-degree polynomial hardening terms of the
criterion are also shown to incorporate the earlier theoretical explained mixed-mode I-II fracture equation, showing hardening
to be based on hindered microcrack extension. For uniaxial loading, the failure criterion can be resolved in factors, leading
to the derivation of extended Hankinson equations. This allows the relations between the constants of the total failure criterion
to be elucidated, which is necessary for data fitting of this criterion and providing a simple method to determine the constants
by the simple uniaxial, oblique-grain compression and tension tests. Based on this, the numerical failure criterion is given
with the simple lower bound criterion for practice and for the codes. 相似文献
10.
- 1. A detailed study on the spatial and temporal patterns of reef fish assemblages associated with non‐reefal coral communities at A Ma Wan (AMW) and A Ye Wan (AYW) in Tung Ping Chau, Hong Kong, China, was carried out using an underwater visual census method from January 1998 to December 1999.
- 2. The study identified a total of 106 species (76 genera in 39 families) of fish in the study sites, in which 88 species were recorded in AMW and 78 species in AYW. Seasonal patterns in the abundance and species richness of all reef fishes and most of the frequently encountered families/trophic groups in both study sites were observed. Seasonal fluctuation of macroalgae, the influence of recruitment of larvae, and the possible seasonal variation in the behaviour of fish may all contribute to these observed seasonal patterns.
- 3. Multidimensional scaling (MDS) ordinations demonstrated that there were spatial variations in the fish community structures within and between sites. Such spatial patterns were possibly related to the spatial variation of the coral community structures in the study sites. The ordinations also showed that the fish community structures in the study sites were not seasonally stable. Such temporal instability of the fish community structures may be partly due to habitat isolation among the fish communities around the island.
- 4. These results imply that preservation and enhancement of habitat connectivity of the coral communities should be one of the main conservation strategies for the reef fish communities of Tung Ping Chau, and those of Hong Kong in general. This strategy may be equally applicable to other non‐reefal coral communities elsewhere around the world.