Effects of Dietary Vitamin C on the Immune Function of Shrimps, Penaeus chinensis     

Wang Weiqing  LI Aijie  Cheung Siugin 《中国海洋大学学报(英文版)》2002,1(1)

Prepared in this experiment were six groups of diets, i.e. VC0, VC1, VC2, VC3, VC4 and VC5 with the contents of vitamin C (VCmg(100g)-1 diet) of 0, 100, 200, 400, 800, and 1200 respectively. It was found that vitamin C increased the concentrations of immunoglobulin-like (IgG-like, IgA-like and IgM-like) substances in the serum of Penaeus chinensis after a feeding period of 3 weeks. The differences among groups were significant (P＜ 0.01), but there was no difference in the contents of complement3-1ike and complement4-1ike substances in the serum (P ＞0.05). Phenoloxidase (PO) activity in the serum of VC3 group shrimps was higher than that of VC0 and other groups, but no significant difference was observed between VC0 group and other groups. Furthermore, bactericidal activity of the serum to Vibrio parahaemolyticus in shrimps fed with the VC1 diet was higher than that in the other groups (P＜ 0.01), while no difference was demonstrated among all groups for the bactericidal activity to Vibrio alginolyticus (P ＞0.05). It is, therefore, suggested that vitamin C (100-400 mg(100 g) -1 diets) could be used as an immunostimulant of P. chinensis.  相似文献   

Assessing the Efficacy of Transition Theory to Identify Industry Transformation: a case study examining the deregulation of Australia's dairy industry     

Katrina Sinclair  Allan Curtis  Emily Mendham  Michael Mitchell 《The Australian geographer》2015,46(1):113-129

Transformation is a key concept in social-ecological systems research, and transition theory in particular; however, the essential elements of a transformation are yet to be clearly articulated. This article explores the changes that took place when Australian governments deliberately set out to restructure the Australian dairy industry. Using the subtropical dairy industry as a case study, we conducted semi-structured interviews with industry stakeholders. Our analysis was structured around transition concepts thus testing the framework's efficacy. We found that deregulation substantially altered the culture of the industry and the structure and working practices of the production system, supply chain, industry organisations and government agencies. Transition theory and its concepts provided a useful framework to explain how systemic change transformed the industry. Transition theory identified the multi-scalar nature of the interactions between structure and practice and the social and power relationships that reinforced change.  相似文献   

The X-ray jet and lobes of PKS 1354+195 (=4C 19.44)     

D. A. Schwartz  D. E. Harris  H. Landt  A. Siemiginowska  H. L. Marshall  J. M. Gelbord  E. S. Perlman  M. Georganopoulos  M. Birkinshaw  D. M. Worrall  C. C. Cheung  L. Stawarz  S. G. Jorstad  A. P. Marscher  Y. Uchiyama  C. M. Urry 《Astrophysics and Space Science》2007,311(1-3):341-345

We present a Chandra image of the quasar, jet, and lobes of PKS 1354+195 (=4C 19.44). The radio jet is 18 arcsec long, and appears to be very straight. The length gives many independent spatial resolution elements in the Chandra image while the straightness implies that the geometrical factors are constant along the jet although their values are uncertain. We also have 4 frequency radio images with half to one arcsecond angular resolution, and use HST and Spitzer data to study the broad band spectral energy distributions. The X-ray and radio spectra are both consistent with a spectrum f _ν ∝ ν ^−0.7 for the integrated jet. Using that spectral index, the model of inverse Compton scattering of electrons on the cosmic microwave background (IC/CMB) gives magnetic field strengths and Doppler factors that are relatively constant along the jet. Extended X-ray emission is evident in the direction of the otherwise unseen counter-jet. X-ray emission continues past the radio jet to the South, and is detected within both the southern and northern radio lobes.  相似文献   

Ten years to prevent catastrophe?: Discourses of climate change and international development in the UK press     

Hugh Doulton  Katrina Brown 《Global Environmental Change》2009,19(2):191-202

The science of climate change is full of uncertainty, but the greater vulnerability of poor countries to the impacts of climate change is one aspect that is widely acknowledged. This paper adapts Dryzek's ‘components’ approach to discourse analysis to explore the media construction of climate change and development in UK ‘quality’ newspapers between 1997 and 2007. Eight discourses are identified from more than 150 articles, based on the entities recognised, assumptions about natural relationships, agents and their motives, rhetorical devices and normative judgements. They show a wide range of opinions regarding the impacts of climate change on development and the appropriate action to be taken. Discourses concerned with likely severe impacts have dominated coverage in the Guardian and the Independent since 1997, and in all four papers since 2006. Previously discourses proposing that climate change was a low development priority had formed the coverage in the Times and the Telegraph. The classification of different discourses allows an inductive, nuanced analysis of the factors influencing representation of climate change and development issues; an analysis which highlights the role of key events, individual actors, newspaper ideology and wider social and political factors. Overall the findings demonstrate media perceptions of a rising sense of an impending catastrophe for the developing world that is defenceless without the help of the West, perpetuating to an extent views of the poor as victims.  相似文献   

Improved absorption cross-sections of oxygen in the wavelength region 205–240 nm of the Herzberg continuum     

K. Yoshino  A.S.-C. Cheung  J.R. Esmond  W.H. Parkinson  D.E. Freeman  S.L. Guberman  A. Jenouvrier  B. Coquart  M.F. Merienne 《Planetary and Space Science》1988,36(12):1469-1475

The laboratory values of the Herzberg continuum absorption cross-section of oxygen at room temperature from Cheung et al. (1986, Planet. Space Sci. 34, 1007), Jenouvrier et al. (1986a, Planet. Space Sci. 34, 253) and Jenouvrier et al. (1986, J. quant. Spectrosc. radiat. Transfer 36, 349) have been compared and re-analyzed. There is no discrepancy between the absolute values of these two sets of independent measurements. These values have been combined together in a linear least-squares fit to obtain improved values of the Herzberg continuum cross-section of oxygen at room temperature throughout the wavelength region 205–240 nm. Agreement with in situ and other laboratory measurements is discussed.  相似文献   

Identification and characterization of a new degradation product of Irgarol-1051 in mercuric chloride-catalyzed hydrolysis reaction and in coastal waters     

Lam KH  Lam MH  Lam PK  Qian T  Cai Z  Yu H  Cheung RY 《Marine pollution bulletin》2004,49(4):361-367

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Statistical and hydrochemical methods to compare basalt- and basement rock-hosted groundwaters: Atherton Tablelands,north-eastern Australia   总被引：1，自引：0，他引：1  

Katrina L. Locsey  Malcolm E. Cox 《Environmental Geology》2003,43(6):698-713

Multivariate analysis of physico-chemical and chemical data has enabled differentiation among groundwaters sourced from different lithological formations in the Atherton Tablelands region of north-eastern Australia. The main water resource is stored in basalt, although basement rocks such as granite and metamorphics also contain variable amounts of water. Groundwater in the basalt is mostly Mg-Ca-Na, HCO₃ type, with electrical conductivities less than 300 µS/cm and pH values from 6.5 to 8.5. Some of the other groundwater is quite similar, making the identification of hydrochemical facies difficult. Groundwater samples were grouped based on the results of a principal component factor analysis of the major dissolved constituents H₄SiO₄, Na⁺, Ca²⁺, Mg²⁺ and HCO₃^-, as well as pH and electrical conductivity. Based on this differentiation it was possible to identify the likely host rocks of groundwaters from unidentified lithological units, define the basalt thickness and provide a better understanding of the groundwater resource. Principal component factor analysis has also been useful in identifying the likely hydrochemical processes controlling the composition of these groundwaters, including the production of weak acids in the soil layers, silicate mineral weathering, ion-exchange reactions, evapotranspiration and the leaching of ions from organic matter. Supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s00254-002-0667-z.  相似文献   

Burrowing responses of the short-neck clam Ruditapes philippinarum to sediment contaminants     

P. K. S. Shin  A. W. M. Ng  R. Y. H. Cheung 《Marine pollution bulletin》2002,45(1-12)

The burrowing responses of a common tropical bivalve, the short-neck clam Ruditapes philippinarum, to cadmium (Cd)-spiked sediment, variations of sediment grain size and natural sediments collected from 15 locations in Hong Kong's inshore waters were investigated through a series of laboratory tests. Results showed that the burrowing response exhibited a negative relationship with an increase in Cd concentration in the spiked sediments. The level of Cd was also found to be directly proportional to the percent mortality of the clam. However, there was no significant difference (p>0.05) in the time elapsed for the clam to burrow into sediments with different grain size composition. The elapsed time for 50% of the test clams to burrow into the sediment (ET₅₀) over a period of 48 h was calculated for the sediment samples collected from the 15 locations. Results of ANOVA showed significant difference (p<0.05) among the sediment samples. Tukey's multiple comparison test revealed two groups of sediments: group 1 containing 3 sediment samples collected from Victoria Harbour and group 2 containing 12 samples obtained from other coastal areas of Hong Kong. The ET₅₀ value for group 1 sediments was found to be greater than 2880 min whilst the ET₅₀ for group 2 sediments had a mean of 173.9 min. Agglomerative classification of the sediment samples, based on metal content (As, Cd, Cr, Cu, Ni, Pb, Zn), also showed two similar groups, suggesting that the ET₅₀ values were correlated with the metal level of the sediment samples. Group 1 sediments collected from Victoria Harbour had greater concentrations of Cd, Cr, Cu, Ni and Zn as compared to that in group 2. The present study demonstrated that high metal content in the sediment tends to inhibit the burrowing responses of the clam and that there is potential to develop the burrowing responses of R. philippinarum as a sublethal sediment toxicity test.  相似文献   

Innovations for conservation and development   总被引：10，自引：0，他引：10  

Katrina Brown 《The Geographical journal》2002,168(1):6-17

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Effects of heavy metals on the survival and feeding behaviour of the sandy shore scavenging gastropod Nassarius festivus (Powys)   总被引：1，自引：0，他引：1  

Cheung SG  Tai KK  Leung CK  Siu YM 《Marine pollution bulletin》2002,45(1-12):107-113

The effects of Cu, Cd, Zn and Cr on the survival and feeding behaviour of the sandy shore scavenging gastropod Nassarius festivus were compared. The 96-h LC₅₀ for Cu, Cd, Zn and Cr were 0.36, 1.52, 1.76 and 36.9 mg l⁻¹, respectively. Four sublethal concentrations of each metal plus a control were prepared and the snails were exposed to experimental solutions for 96 h. Feeding behaviour was studied after the snails were starved for five days. As compared with the control, the number of individuals feeding was significantly reduced by exposure to 0.05 mg l⁻¹ Cu, 0.2 mg l⁻¹ Zn, 0.5 mg l⁻¹ Cd and 5 mg l⁻¹ Cr. The time spent feeding was greater for individuals exposed to greater concentrations of Zn and Cd but no effect was found for Cu and Cr. Chemoreception of food was studied by placing the snails at a fixed distance of 15 cm from the bait. The success rate of reaching the bait was less for individuals exposed to Cr but no effect was found for Zn, Cu or Cd. The time required for an individual to reach the bait decreased as the concentration of Zn increased. In contrast, a longer time was required for individuals exposed to Cr whereas the effect of Cd and Cu was insignificant. The potential of using feeding behaviour and chemoreception in contaminant evaluations is discussed.  相似文献