Differences in leaf construction cost between alien and native mangrove species in Futian, Shenzhen, China: implications for invasiveness of alien species   总被引：1，自引：0，他引：1  

Li F  Yang Q  Zan Q  Tam NF  Shin PK  Vrijmoed LL  Cheung SG 《Marine pollution bulletin》2011,62(9):1957-1962

Construction cost (CC) is a quantifiable measure of energy demand for biomass production, and low CC is hypothesized to give an alien plant growth advantages and increase its potential to be an invader. Comparison of leaf CC and growth traits between alien and native mangroves in Shenzhen Futian Nature Reserve showed CC per unit mass (CC_mass), carbon concentration and gross and ash-free caloric values of alien mangroves were significantly lower than those of native species, while the height and chest circumference were just the opposite. Alien species Sonneratia apetala had the lowest CC_mass while Sonneratia caseolaris had the lowest CC_area, and were 8.99% and 32.17% lower than those of native species, respectively. Conversely, specific leaf area (SLA) of these two Sonneratia species was significantly higher than native species. Lower CC and higher SLA make the two Sonneratia species grow and spread faster than other mangroves and enhance their invasive potential.  相似文献   

AFLP analysis of genetic variation among three natural populations of horseshoe crab Tachypleus tridentatus along Chinese coast     

����  �·�  ������  ���ؼ�  ����  �²Ż� 《中国海洋湖沼学报》2011,29(2):284-289

The AFLP(amplified fragment length polymorphism) technique was used to analyze and compare the genetic diversity of Tachypleus tridentatus from three south-eastern coastal sites of China(Pingtan,Hong Kong and Beihai).Eight pairs of primers generated 361 loci,including 285 polymorphic loci.The ratio of polymorphic loci was 96.97%.Nei's genetic diversity index was 0.420 8 and the Shannon information index was 0.607 5,both of which were higher than that reported for many other arthropods.These results show tha...  相似文献   

Response of meiofaunal and nematode communities to sewage pollution abatement: a field transplantation experiment   总被引：1，自引：0，他引：1  

������  ���ؼ�  ������ 《中国海洋湖沼学报》2011,29(6):1174-1185

To assess the recovery rate of meiofaunal and nematode communities upon abatement of sewage pollution, a field transplantation experiment was conducted in Tai Tam, which is a non-polluted, shallow subtidal habitat on the southern portion of Hong Kong Island. The sediments used were from one site located in Victoria Harbour that was heavily influenced by sewage pollution, and one site in the outside-harbor area, which was relatively clean. In addition, sediments from Tai Tam were used as a control. Fresh sediments with meiofauna were collected from the aforementioned sites, placed in plastic trays and transplanted to Tai Tam. Sediments were retrieved at the beginning of the experiment and at 1-, 3-, and 8-weeks after transplantation for analysis of the meiofaunal and nematode communities as well as the sediment characteristics. The results showed that the meiofaunal and nematode communities in the control sediments were consistent at the four sampling periods, while it took three and eight weeks, respectively, for the nematode communities from the outside-harbor and inside-harbor sites to become similar to the control. These findings indicated that the relatively poor habitat quality and the nematode community composition in the sewage polluted inside-harbor sediments required a longer time for recovery than samples from the better habitat quality and the nematode community composition in the outside-harbor sediments.  相似文献   

Vertical response of single piles: transient analysis by time-domain BEM     

Z.X. Lei  Y.K. Cheung  L.G. Tham 《Soil Dynamics and Earthquake Engineering》1993,12(1)

The transient dynamic response of single piles in a layered half-space under a time-dependent vertical force is analyzed by an FEM-BEM coupling approach. The pile is modeled by FEM and the layered half-space is modeled by a general cylindrical coordinates time-domain BEM. Only one-dimensional discretization is necessary on the boundaries of the three-dimensional layered half-space by virtue of the Fourier theory, while the pile shaft can be discretized as a one-dimensional elastic beam. The compatibility and equilibrium conditions between pile shaft and soil layers are employed to assemble respective equations into one. Fairly good agreement between two unknown solutions and the current approach is found. Parametric studies reveal the influences of several dimensionless factors, such as E_p/E_s, l/r₀, _p/_s and ν_s. The effect of soil layering and the support condition of the pile tip is also reported by numerical examples.  相似文献   

Development of Voronoi-based cellular automata -an integrated dynamic model for Geographical Information Systems     

Wenzhong Shi  Matthew Yick Cheung Pang 《International journal of geographical information science》2013,27(5):455-474

This paper presents a development of the extended Cellular Automata (CA), a Voronoi-based CA, to model dynamic interactions among spatial objects. Cellular automata are efficient models for representing dynamic spatial interactions. A complex global spatial pattern is generated by a set of simple local transition rules. However, its original definition for a two-dimensional array limits its application to raster spatial data only. This paper presents a newly developed Voronoi-based CA in which the CA is extended by using the Voronoi spatial model as its spatial framework. The Voronoi spatial model offers a ready solution to handling neighbourhood relations among spatial objects dynamically. By implementing this model, we have demonstrated that the Voronoi-based CA can model local interactions among spatial objects to generate complex global patterns. The Voronoi-based CA can further model interactions among point, line and polygon objects with irregular shapes and sizes in a dynamic system. Each of these objects possesses its own set of attributes, transition rules and neighbourhood relationships. The Voronoi-based CA models spatial interactions among real entities, such as shops, residential areas, industries and cities. Compared to the original CA, the Voronoi-based CA is a more natural and efficient representation of human knowledge over space.  相似文献   

Stellar collisions during binary–binary and binary–single star interactions     

J. M. Fregeau  P. Cheung  S. F. Portegies Zwart  F. A. Rasio 《Monthly notices of the Royal Astronomical Society》2004,352(1):1-19

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Supernova remnant G292.2–0.5, its pulsar, and the Galactic magnetic field     

J. L. Caswell  N. M. McClure-Griffiths  M. C. M. Cheung 《Monthly notices of the Royal Astronomical Society》2004,352(4):1405-1412

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Simple metrics for representing East Asian winter monsoon variability: Urals blocking and western Pacific teleconnection patterns   总被引：1，自引：0，他引：1  

Hoffman H. N. Cheung  Wen Zhou 《大气科学进展》2016,33(6):695-705

Instead of conventional East Asian winter monsoon indices(EAWMIs), we simply use two large-scale teleconnection patterns to represent long-term variations in the EAWM. First, the Urals blocking pattern index(UBI) is closely related to cold air advection from the high latitudes towards western Siberia, such that it shows an implicit linkage with the Siberian high intensity and the surface air temperature(SAT) variations north of 40?N in the EAWM region. Second, the well-known western Pacific teleconnection index(WPI) is connected with the meridional displacement of the East Asian jet stream and the East Asian trough. This is strongly related to the SAT variations in the coastal area south of 40?N in the EAWM region.The temperature variation in the EAWM region is also represented by the two dominant temperature modes, which are called the northern temperature mode(NTM) and the southern temperature mode(STM). Compared to 19 existing EAWMIs and other well-known teleconnection patterns, the UBI shows the strongest correlation with the NTM, while the WPI shows an equally strong correlation with the STM as four EAWMIs. The UBI–NTM and WPI–STM relationships are robust when the correlation analysis is repeated by(1) the 31-year running correlation and(2) the 8-year high-pass and low-pass filter. Hence,these results are useful for analyzing the large-scale teleconnections of the EAWM and for evaluating this issue in climate models. In particular, more studies should focus on the teleconnection patterns over extratropical Eurasia.  相似文献   

Evaluating the impacts of cumulus,land surface and ocean surface schemes on summertime rainfall simulations over East-to-southeast Asia and the western north Pacific by RegCM4     

Yu-Bin Li  Chi-Yung Tam  Wan-Ru Huang  Kevin K. W. Cheung  Zhiqiu Gao 《Climate Dynamics》2016,46(7-8):2487-2505

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Confidence and Trust in Public Institution Natural Hazards Management: Case Studies in Urban and Rural China     

Alex Y. Lo  Lewis T. O. Cheung  Anna Ka-Yin Lee  Bixia Xu 《The Professional geographer》2016,68(3):475-484

This research aims to investigate the extent to which urban and rural residents trust grassroots-level institutions and how this might affect community resilience to environmental change in China. It focuses on the commitments of institutional actors and their capacities to manage natural hazards and coordinate the community's response. Semistructured interviews were conducted with megacity (Tianjin) and remote village (Wolong) residents in China. We found that public confidence in grassroots-level institutions is limited due to inherent constraints on resources and power. Residents of Wolong tend to recognize the commitment and role of those institutions in connecting individuals with one another, whereas their urban counterparts in Tianjin remain skeptical. Issues of solidarity might account for this difference. These findings will have implications for state–society cooperation and disaster risk comanagement in both urban and rural China.  相似文献