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41.
Kunal Saha Kalpana Dash Arvind Sahu 《Comparative immunology, microbiology and infectious diseases》1993,16(4):323-330
The present communication is a continuation of our earlier study on the natural serum haemagglutinin/lectins of Cirrhina mrigala, Clarias batrachus and Heteropneustes fossilis. Sera of Cirrhina mrigala, belonging to the major carp family, could not only agglutinate heterologous rabbit erythrocytes, but also lyse them spontaneously. This lysis of rabbit RBC by Cirrhina mrigala sera was calcium ion dependent and heat sensitive, indicating thereby that the haemolysis was mediated by the fish serum complement system via the classical pathway. Quantification of CH50 and APCH50 levels in the sera of Clarias batrachus and Heteropneustes fossilis as well as in the sera of amphibia, aves and mammals showed that lower vertebrates predominantly possessed an alternative pathway of the complement system, while on the other hand, in the higher vertebrates the major pathway of complement activation was classical. Furthermore sera of Clarias batrachus and Heteropneustes fossilis had opsonins, which could stimulate heterologous rat peritoneal macrophages to engulf Staphylococcus aureus with the production of superoxide anion. From this study we concluded that fishes have been armed with various powerful natural humoral defense systems for their protection against environmental pathogens. 相似文献
42.
Swapan Kumar Sarker Muhammad Nur-Un-Nabi Md.Mohasinul Haque Mahmuda Sharmin Sanjay Saha Sonet Sourav Das Niamjit Das 《林业研究》2015,(1):159-169
Juri is a biodiversity-rich primary forest in Bangladesh, which remains ecologically unexplored. We identified tree species and examined the richness, alpha(a)diversity and floristic similarity patterns within the identified communities. Vegetation and environmental data were sampled in 120(0.04 ha) study plots. Tree communities were delimited by two-way indicator species analysis(TWINSPAN). In total, 78 tree species of 35 families and58 genera were identified. TWINSPAN identified six tree communities: A—Tricalysia singularis; B—Kydia calycina-Castanopsis tribuloides; C—Polyalthia simiarum-Duabanga grandiflora; D—Ficus roxburghii; E—Artocarpus lacucha; F—Artocarpus lacucha. Mean richness, Shannon and Gini-Simpson indices were highest for the Polyalthia simiarum-Duabanga grandiflora community, while Ficus roxburghii showed lowest diversity. Significant differences(p = 0.05) in three diversity indices were recorded between Polyalthia simiarum-Duabanga grandiflora and Ficus roxburghii. Tree compositional similarity was greatest between Kydia calycina-Castanopsis tribuloides and Polyalthia simiarum-Duabanga grandiflora(0.712). 相似文献
43.
Context
Cluster planting has become a conventional establishment method for oaks in Central Europe, where the spacing of seedlings within clusters varies between ‘nests’ (0.2?×?0.2 m) and ‘groups’ (1?×?1 m). Although the space between clusters is expected to fill with voluntary regeneration, its competitive effect on oak growth and quality had not been studied yet.Aims
The aim of the study was to analyse the effects of inter- and intraspecific interactions on growth and quality of oaks grown in cluster plantings by quantifying the influence of neighbouring trees. In addition, we analysed whether the spatial position of oaks within groups (inner section or periphery) influenced their quality development.Methods
Using Hegyi’s competition index, the influence of competition from intra- and interspecific trees from early, mid- and late-successional species, on diameter, height, slenderness and quality (length of branch-free bole) of 10- to 26-year-old oaks grown in cluster planting stands was quantified at seven sites in Baden-Württemberg and Hessen, Germany.Results
In general, mid- and late-successional trees exerted a stronger competitive influence on growth of target oaks in clusters than the conspecific oaks and pioneer tree species. Oak quality development benefited from intraspecific competition, but self-pruning was not further promoted through additional interspecific competition. Within groups, inner oaks had a higher probability of developing into potential future crop trees than outer oaks.Conclusion
Our study showed that intra- and interspecific competition had different effects on target oak trees and that these effect differed between nest and group plantings. The development of naturally regenerated and planted trainer trees in group plantings should be monitored carefully and if necessary be controlled through thinning or pollarding. 相似文献44.
Subedi R Shneor R Monaghan P Anderson BD Aniol K Annand J Arrington J Benaoum H Benmokhtar F Boeglin W Chen JP Choi S Cisbani E Craver B Frullani S Garibaldi F Gilad S Gilman R Glamazdin O Hansen JO Higinbotham DW Holmstrom T Ibrahim H Igarashi R de Jager CW Jans E Jiang X Kaufman LJ Kelleher A Kolarkar A Kumbartzki G Lerose JJ Lindgren R Liyanage N Margaziotis DJ Markowitz P Marrone S Mazouz M Meekins D Michaels R Moffit B Perdrisat CF Piasetzky E Potokar M Punjabi V Qiang Y Reinhold J Ron G 《Science (New York, N.Y.)》2008,320(5882):1476-1478
The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, in which a proton is knocked out of the nucleus with high-momentum transfer and high missing momentum, show that in carbon-12 the neutron-proton pairs are nearly 20 times as prevalent as proton-proton pairs and, by inference, neutron-neutron pairs. This difference between the types of pairs is due to the nature of the strong force and has implications for understanding cold dense nuclear systems such as neutron stars. 相似文献
45.
Samarium-neodymium data for nine granitic and tonalite gneisses occurring as remnants within the Singhbhum granite batholith in eastern India define an isochron of age 3775 +/- 89 x 10(6) years with an initial (143)Nd/(144)Nd ratio of 0.50798 +/- 0.00007. This age contrasts with the rubidium-strontium age of 3200 x 10(6) years for the same suite of rocks. On the basis of the new samarium-neodynium data, field data, and petrologic data, a scheme of evolution is proposed for the Archean crust in eastern India. The isotopic data provide evidence that parts of the earth's mantle were already differentiated with respect to the chondritic samarium-neodymium ratio 3800 x l0(6) years ago. 相似文献
46.
Summary The genetics of stem elongation ability in rice was studied in parents, F1, F2 and backcross generations of six crosses. Segregation analysis indicated dominance for stem elongation ability. Estimation of genetic parameters under epistatic model indicated more than one locus control stem elongation ability and both additive and nonadditive gene effects were important. Epistatic effects were predominant over additive and dominance effects with an important role of duplicate type of epistasis. The occurrence of significant additive and additive x additive types of genetic variation and the moderately high broad sense heritability indicated the possibility of selection for an increased manifestation of stem elongation ability. 相似文献
47.
48.
Tropical Animal Health and Production - Search for cost-effective, eco-friendly and sustainable plant resources as potential feedstuff to replace fishmeal in the formulation of feed for fish has... 相似文献
49.
Effect of polyacrylamide and gypsum on surface runoff, sediment yield and nutrient losses from steep slopes 总被引:1,自引:0,他引:1
Hilly terrains with steep slopes and poor vegetative cover are prone to soil erosion. Crop productivity from such lands can be increased by adding correct amounts of soil conditioners such as polyacrylamide (PAM) and gypsum (G) to reduce soil erosion and to improve settling of suspended sediment. The field experiments were conducted in hilly areas with 97% land slope to evaluate the effectiveness of PAM and G when applied as single and concurrent doses of 20 and 2500 kg ha−1, respectively to check surface runoff, sediment yield and major nutrient (N, P, and K) losses under natural rainfall conditions. The results indicate that concurrent application of PAM and G was most effective closely followed by G alone. However, considering the costs of PAM and gypsum and labor involved in their concurrent application on large scale, the application of gypsum alone is recommended in controlling the surface runoff, sediment yield and major nutrient losses from steeply sloped lands in Indian Himalayas. 相似文献
50.
P. S. Srivastava S. R. P. Sinha P. D. Juyal A. K. Saha 《Veterinary research communications》1987,11(2):185-190
A marked reduction in the faecal excretion of sporocysts was observed in experimental pups, following the repeated oral administration to them of buffalo cardiac muscle infected with Sarcocystis levinei. Sporocysts excreted from days 9 to 25 post-infection (pi) exhibited a gradual reduction in the quantum. Maximum intensity of excretion of sporocysts was recorded between days 9 and 16 pi, becoming moderate after day 16, light after day 21 and completely absent after day 36. After the subsequent feeding to pups of S. levinei infected buffalo cardiac tissues at 40 day intervals the quantity of sporocysts shed was less, the prepatent period was prolonged and the patent period was considerably shortened. The peak period of excretion varied depending upon the number of exposures of the pups to the infected S. levinei tissues from buffaloes (Bubalus bubalis). 相似文献