Elite maize hybrid Guidan0810 was selected as material, and the effects of fertilizing level and planting densities on yield and nitrogen utilization were dis- cussed in the study. In field experiments as per double-c...Elite maize hybrid Guidan0810 was selected as material, and the effects of fertilizing level and planting densities on yield and nitrogen utilization were dis- cussed in the study. In field experiments as per double-cropping system, 4 main plots (fertilization levels) and 6 subplots (planting densities) were set in a split plot design. The results suggested that yield had close relationship with fertilization levels and planting densities. Different fertilization levels and planting densities significantly affected yield. With the increase of nitrogen fertilization, nitrogen use efficiency, nitrogen agronomic efficiency and nitrogen physiological efficiency declined. Under the same fertilization level, nitrogen use efficiency, nitrogen agronomic efficiency and nitrogen physiological efficiency grew a little with the increase of planting density, so nitrogen efficiency could be improved by regulating planting density. The results also showed that A2 (including N 225.0 kg/hm2, P205 75.0 kg/hm^2, K20 187.5 kg/hm^2) matching to B3 (52 500 plants/hm^2) or B4(60 000 plants/hm^2) was a better design, which could obtain a higher yield in the range of 7 913.2-8 207.8 kg/hm2, respectively.展开更多
In summer, Cha No. 39 of 292 bags and 205 of 244 bags were inter- planted with Dendrobium officinale on cultivation bed, respectively, whose yields and biological efficiencies reached 102.46 kg and 103.98%, and 96.77 ...In summer, Cha No. 39 of 292 bags and 205 of 244 bags were inter- planted with Dendrobium officinale on cultivation bed, respectively, whose yields and biological efficiencies reached 102.46 kg and 103.98%, and 96.77 kg and 113.32%, accordingly. The seedlings of Dendrobium officinale interplanted with Pleurotus os- treatus grew by 2.78 cm during 10 weeks on cultivation beds, and the seedlings grew by 2.68 cm in the cultivation beds without interplanting arrangement. These demonstrated that the interplanting of Dendrobium officinale and Pleurotus ostreatus has none adverse effects on growth of Dendrobium officinale.展开更多
[Purpose] The paper is to discuss the high-efficient breeding technology platform of dwarf male-sterile wheat.[Method] Conclusion was made upon the development of the creation and application of dwarf male-sterile whe...[Purpose] The paper is to discuss the high-efficient breeding technology platform of dwarf male-sterile wheat.[Method] Conclusion was made upon the development of the creation and application of dwarf male-sterile wheat,and the conception of introducing haploid breeding technology into the technological system of high-efficient breeding of dwarf male-sterile wheat was proposed.[Result] Dwarf male-sterile wheat not only retains the properties of total male abortion of Taigu Genetic Sterile Wheat,steady sterility,and high hybrid rate after open pollination,but also has the characteristic of high dwarfing ability of Aibian No.1,becoming a comparatively ideal population modification means.At present,the application of dwarf male-sterile wheat mainly includes germplasm resources platform of population modification by using dwarf male-sterile wheat,technology platform of constructing new high-efficient breeding system by using dwarf male-sterile wheat,and production platform of using dwarf male-sterile wheat to breed new varieties.Through the introduction of haploid breeding into the already established wheat high-efficient breeding system,a new system of high-efficient biological breeding technology of dwarf male-sterile wheat was constructed theoretically.[Conclusion] The study provides references to the further study and application of dwarf male-sterile wheat.展开更多
[Objective] The aim was to provide molecular basis for the identification of species in the moss family Bryaceae by the construction of inter-simple sequence repeats (ISSR) fingerprinting. [Method] In order to seek ...[Objective] The aim was to provide molecular basis for the identification of species in the moss family Bryaceae by the construction of inter-simple sequence repeats (ISSR) fingerprinting. [Method] In order to seek standardizing PCR reaction set-up, an orthogonal design was used to optimize ISSR-PCR amplification system of Bryaceae in five factors (Mg2+, dNTPs, primer, DNA template, Taq DNA polymerase) at four levels respectively. [Result] A suitable ISSR reaction system was obtained, namely: 20 μl reaction system containing 5 ng of DNA template, 0.2 μmol/L primer, 2.25 mmol/L MgCl2, 0.6 U of Taq DNA polymerase, 0.4 mmol/L dNTPs. Proper annealing temperature was found at 48-50 ℃.The above system and six ISSR-PCR primers were used for the PCR amplification of 14 samples from Bryaceae and the related species in Mniaceae. A total of 86 bands were amplified, all showed polymorphism. NJ cluster analysis showed a star-shaped cladogram. [Conclusion] The results manifested that ISSR fingerprinting could provide the appropriate degree of polymorphism at low taxonomic level, so it would be a useful tool to provide additional evidence for resolving taxonomic relationships at the species level of Bryaceae.展开更多
A new breeding population of Mandarin Duck (Aix gaIericulata, Linnaeus) was first recorded in 2003 in Jiao- tanzhuang-Hehekou region of Pingshan county, Hebei Province, China. Recently, the gradually increasing popu...A new breeding population of Mandarin Duck (Aix gaIericulata, Linnaeus) was first recorded in 2003 in Jiao- tanzhuang-Hehekou region of Pingshan county, Hebei Province, China. Recently, the gradually increasing population indicates that there are suitable breeding habitats (such as foraging habitats and nesting sites) for Mandarin Duck. However, these habitats are always close to human disturbances, which are the potential risk for their population. Therefore, it is urgent to put forward an applicable protection strategy, in order to strengthen the public awareness for this unprotected population.展开更多
[Objective] The aim was to research balance between manure of breeding farm and farmland load. [Method] N balance of farmlands after manure fertilized was researched in a hoggery in Beijing (600 base sows and 647 bre...[Objective] The aim was to research balance between manure of breeding farm and farmland load. [Method] N balance of farmlands after manure fertilized was researched in a hoggery in Beijing (600 base sows and 647 breeding pigs). [Result] The suitable N input in neighboring farmlands was 191.9 kg/(hm 2 ·y) and the farmland area satisfying balance between growing and breeding was 53.7 hm 2 in the hoggery. [Conclusion] The research provided a scientific method for balance between growing and breeding.展开更多
By field experiments with Uniform Design, the effects of planting density and nitrogen rate on three varieties (Yunrui No.8, Yunrui No.6 and Yunrui No.88) grain yield under different ecological conditions were studi...By field experiments with Uniform Design, the effects of planting density and nitrogen rate on three varieties (Yunrui No.8, Yunrui No.6 and Yunrui No.88) grain yield under different ecological conditions were studied in Yunnan Province. The results showed that the grain yields were different among the five experiment locations, when increasing of planting density, it did not affected the plant height, ear height and ear factor, with the planting density increased, stem diameter, leaf width, ear length, number of grains per row and 1 000-grain weight decreased sig- nificantly, but the grain yield of the third varieties increased. High planting density had a negative impact on ear traits, but the grain yield increased by high-density compensate for the adverse effects.Control space and time of fertilizer application can reach the highest yield under less Nitrogen fertilizer Yunrui 88 had the charec- teristics of wide range of adaptability and the density-tolerance, high-yielding poten- tial, which was favorable in planting on large areas.展开更多
Total mercury concentration of typical wetland plants was analyzed in thispaper. There were great differences of total mercury concentration among different plants:moss>hydrophyte>sedge>herbage>shrub. Tota...Total mercury concentration of typical wetland plants was analyzed in thispaper. There were great differences of total mercury concentration among different plants:moss>hydrophyte>sedge>herbage>shrub. Total mercury concentrations show an increasing trend fromvascular plants to bryophytes, and from dry to wet lands. The mercury concentration of wetlandplants was higher than that of crops. The wetland soil was the source of mercury in the air close tothe ground, so it affected the concentration of mercury in the plant. In different parts of aplant, mercury concentration was in the order of: dead stand>root>leaf>stem. Mercury concentrationincreased at the initial stage and decreased in the end of the growing season. According to themercury content and biomass, mercury stock of plants was 39.4μg/m^2 above ground in Calamagrostisangustifolia wetland and 35.8μg /m^2 in Carex lasiocarpa wetland.展开更多
AIM: To investigate the effect of Mirtazapine on tumor growth, food intake, body weight, and nutritional status in gemcitabine-induced mild cachexia. METHODS: Fourteen mice with subcutaneous xenografts of a pancreatic...AIM: To investigate the effect of Mirtazapine on tumor growth, food intake, body weight, and nutritional status in gemcitabine-induced mild cachexia. METHODS: Fourteen mice with subcutaneous xenografts of a pancreatic cancer cell line (SW1990) were randomly divided into Mirtazapine and control groups. Either Mirtazapine (10 mg/kg) or saline solution was orally fed to the mice every day after tumor implantation. A model of mild cachexia was then established in both groups by intraperitoneal injection of Gemcitabine (50 mg/kg) 10 d, 13 d, and 16 d after tumor implanta- tion. Tumor size, food intake, body weight, and nutritional status were measured during the experiment. All mice were sacrificed at day 28. RESULTS: (1) After 7 d of gemcitabine administration, body-weight losses of 5%-7% which suggested mild cachexia were measured; (2) No significant difference in tumor size was detected between the Mirtazapine and control groups (P > 0.05); and (3) During the entire experimental period, food intake and body weight were slightly greater for the Mirtazapine group compared with controls (although these differences were not statistically significant). After 21 d, mice in the Mirtazapine group consumed significantly more food than control mice (3.95 ± 0.14 g vs 3.54 ± 0.10 g, P = 0.004). After 25 d, mice in the Mirtazapine group were also significantly heavier than control mice (17.24 ± 0.53 g vs 18.05 ± 0.68 g, P = 0.014). CONCLUSION: Mild cachexia model was successfully established by gemcitabine in pancreatic tumor-bearing mice. Mirtazapine can improve gemcitabine-induced mild cachexia in pancreatic tumor-bearing mice. It was believed to provide a potential therapeutic perspective for further studies on cachexia.展开更多
This paper reports for the first time a species of polychaetous family Paraonidae, Paraonella platybranchia (Hartman, 1961), a rare species found previously only in the coast near the boundary between the United State...This paper reports for the first time a species of polychaetous family Paraonidae, Paraonella platybranchia (Hartman, 1961), a rare species found previously only in the coast near the boundary between the United States and Mexico, and it was recently discovered in the samples collected in 1982 from Chinese side of the Yellow Sea. This is the first record of the species in China as well as in the Northwest Pacific.展开更多
This paper describes a new species of Nassarius from the South China Sea,which was recognized when re-sorting the collection of Nassariidae in the Marine Biological Museum,Chinese Academy of Sciences,Qingdao,China.The...This paper describes a new species of Nassarius from the South China Sea,which was recognized when re-sorting the collection of Nassariidae in the Marine Biological Museum,Chinese Academy of Sciences,Qingdao,China.The shells were collected during several investigations,including the National Comprehensive Oceanic Survey in 1958-1959,and the China-Vietnam Co-Investigation on Marine Resource of the Beibu Gulf during 1959-1962.The morphology of the shell and the radula places the new species of Nassarius within the subgenus Zeuxis.It is named Nassarius(Zeuxis) nanhaiensis sp.nov.展开更多
On the basis of population balance a mathematical model is developed to describe the formation of polymer particle in styrene suspension polymerization. The characteristics of coalescence and breakage of droplets and ...On the basis of population balance a mathematical model is developed to describe the formation of polymer particle in styrene suspension polymerization. The characteristics of coalescence and breakage of droplets and the gel effect are analyzed in particular. Parameters of the models are estimated by experimental data on reaction conversion and particle size distribution. The results show that the model is suitable for predicting polymerization processes.展开更多
Based on the data from the Cost-benefit Data of Farm Produce and the China Agricultural Yearbook, this paper aims to examine the spatial and temporal change characteristics of total grain production and its affecting ...Based on the data from the Cost-benefit Data of Farm Produce and the China Agricultural Yearbook, this paper aims to examine the spatial and temporal change characteristics of total grain production and its affecting factors. The results show that: 1) During 1980 to 2007, total grain production increased from 3.20 ~ 108 t to 5.02 x 108 t in China, with annual increasing rate of 1.68%. From the regional disparities, most of the regions present increasing trend of total grain production except for several regions with higher level of economic development; 2) Grain sown area decreased from 1.17 × 108 ha in 1980 to 1.06 x 108 ha in 2007, which has negative effect on total grain production; 3) The increase of grain yield per unit area caused by land use intensity changes contributed to the increase of total grain yield greatly. However, as the land use intensity showed that farmers pay more attention to labor-saving input but not yield-increasing input, the less enthusiasm of farmers in grain production may become an important constraint on fu- ture grain production increase in China; 4) Based on the results, this paper proposed different land management poli- cies in different regions, for example, the government should protect cultivated land, promote large scale production. As to the less developed regions, the government should pay more attention to agricultural subsidies to promote farm- ers' enthusiasm in grain production.展开更多
Unsystematic selection and planting of tree seedlings in road borders, forest regeneration, development of parks and green spaces which are incompatible with the given climate zone, is a kind of interference and viola...Unsystematic selection and planting of tree seedlings in road borders, forest regeneration, development of parks and green spaces which are incompatible with the given climate zone, is a kind of interference and violation of ecosystem privacy. Therefore, the stability and persistence of species in the forest protection is important for planners of natural resources. Field station of spreading Dehloran aquifer is one of the major forestations in Ilam province. It aimed of protecting the soil and underground water table feeding in hot dry plains of Mosian, which have been planted with native and non-native species. In the present article 100 trees of each species were planted during the years 1998 and 1999 in the station, such as Ziziphus spina-christi, Prosopis juliflora, Eucalyptus camaldulensis and Acacia sp. They were randomly selected and information about this species measured and recorded annually has been used. Finally the data has been analysis; by comparison test to compare the growth and persistence. Results indicate that despite high average in height growth (85.4 cm/year) and relatively large diameter growth (2.43 cm/year), non-native species of Eucalyptus are not in good condition in terms of viability (36.2 percent) and freshness. On the contrary, the native species of Ziziphus with relatively low in average height and diameter growth (22.64 and 2.28 cm/year respectively) represent a better index of viability (65.4 percent) and freshness.展开更多
The Thai mahseer is one of the high-value freshwater fish species, especially m Malaysia where it is cultured commercially but poorly known in Thailand. This paper reviews a recent knowledge necessary for commercial c...The Thai mahseer is one of the high-value freshwater fish species, especially m Malaysia where it is cultured commercially but poorly known in Thailand. This paper reviews a recent knowledge necessary for commercial culture of Thai mahseer based on the breeding and rearing practices in Malaysia. Breeding data shows that this species can be spawned all year round. On average, the size of mature female that can be induced to spawn is 678 mm total length (TL) and 3,817 g in weight and the size of mature male is 599 mm TL and 2,414 g in weight. Induced spawning using an analogue of sGnRH Ovaprim at 0.5 ml/kg body weight (BW) is the most successful hormone treatment and dosage for Thai mahseer. The average number of eggs is 875 egg/kg BW. Eggs of the Thai mahseer are spherical, demersal and non-sticky, and hatching occurs 69-90 hours post-fertilization. At 60 weeks of age, average body weight is 179 g. Polynomial regression analysis revealed a maximum specific growth rate at 48% dietary protein. General biology, water quality requirements, feeding strategies and genetic structure of the Thai mahseer are also summarized in this paper.展开更多
Relatively short historical catch records show that anchovy populations have exhibited large variability over multi-decadal timescales.In order to understand the driving factors(anthropogenic and/or natural) of such v...Relatively short historical catch records show that anchovy populations have exhibited large variability over multi-decadal timescales.In order to understand the driving factors(anthropogenic and/or natural) of such variability,it is essential to develop long-term time series of the population prior to the occurrence of notable anthropogenic impact.Well-preserved fish scales in the sediments are regarded as useful indicators reflecting the fluctuations of fish populations over the last centuries.This study aims to validate the anchovy scale deposition rate as a proxy of local anchovy biomass in the Yellow Sea adjoining the western North Pacific.Our reconstructed results indicated that over the last 150 years,the population size of anchovy in the Yellow Sea has exhibited great fluctuations with periodicity of around 50 years,and the pattern of current recovery and collapse is similar to that of historical records.The pattern of large-scale population synchrony with remote ocean basins provides further evidence proving that fish population dynamics are strongly affected by global and basin-scale oceanic/climatic variability.展开更多
文摘Elite maize hybrid Guidan0810 was selected as material, and the effects of fertilizing level and planting densities on yield and nitrogen utilization were dis- cussed in the study. In field experiments as per double-cropping system, 4 main plots (fertilization levels) and 6 subplots (planting densities) were set in a split plot design. The results suggested that yield had close relationship with fertilization levels and planting densities. Different fertilization levels and planting densities significantly affected yield. With the increase of nitrogen fertilization, nitrogen use efficiency, nitrogen agronomic efficiency and nitrogen physiological efficiency declined. Under the same fertilization level, nitrogen use efficiency, nitrogen agronomic efficiency and nitrogen physiological efficiency grew a little with the increase of planting density, so nitrogen efficiency could be improved by regulating planting density. The results also showed that A2 (including N 225.0 kg/hm2, P205 75.0 kg/hm^2, K20 187.5 kg/hm^2) matching to B3 (52 500 plants/hm^2) or B4(60 000 plants/hm^2) was a better design, which could obtain a higher yield in the range of 7 913.2-8 207.8 kg/hm2, respectively.
基金Supported by Fundamental Research Funds for Guangxi Academy of Sciences(13YJ22SWS20)~~
文摘In summer, Cha No. 39 of 292 bags and 205 of 244 bags were inter- planted with Dendrobium officinale on cultivation bed, respectively, whose yields and biological efficiencies reached 102.46 kg and 103.98%, and 96.77 kg and 113.32%, accordingly. The seedlings of Dendrobium officinale interplanted with Pleurotus os- treatus grew by 2.78 cm during 10 weeks on cultivation beds, and the seedlings grew by 2.68 cm in the cultivation beds without interplanting arrangement. These demonstrated that the interplanting of Dendrobium officinale and Pleurotus ostreatus has none adverse effects on growth of Dendrobium officinale.
基金Supported by Innovation Center of Agricultural Sciences,HubeiProvince~~
文摘[Purpose] The paper is to discuss the high-efficient breeding technology platform of dwarf male-sterile wheat.[Method] Conclusion was made upon the development of the creation and application of dwarf male-sterile wheat,and the conception of introducing haploid breeding technology into the technological system of high-efficient breeding of dwarf male-sterile wheat was proposed.[Result] Dwarf male-sterile wheat not only retains the properties of total male abortion of Taigu Genetic Sterile Wheat,steady sterility,and high hybrid rate after open pollination,but also has the characteristic of high dwarfing ability of Aibian No.1,becoming a comparatively ideal population modification means.At present,the application of dwarf male-sterile wheat mainly includes germplasm resources platform of population modification by using dwarf male-sterile wheat,technology platform of constructing new high-efficient breeding system by using dwarf male-sterile wheat,and production platform of using dwarf male-sterile wheat to breed new varieties.Through the introduction of haploid breeding into the already established wheat high-efficient breeding system,a new system of high-efficient biological breeding technology of dwarf male-sterile wheat was constructed theoretically.[Conclusion] The study provides references to the further study and application of dwarf male-sterile wheat.
基金Supported by Natural Science Foundation of Hebei Province(C2006000147)Zhengzhou Science and Technology Program(10PTGN449-6)~~
文摘[Objective] The aim was to provide molecular basis for the identification of species in the moss family Bryaceae by the construction of inter-simple sequence repeats (ISSR) fingerprinting. [Method] In order to seek standardizing PCR reaction set-up, an orthogonal design was used to optimize ISSR-PCR amplification system of Bryaceae in five factors (Mg2+, dNTPs, primer, DNA template, Taq DNA polymerase) at four levels respectively. [Result] A suitable ISSR reaction system was obtained, namely: 20 μl reaction system containing 5 ng of DNA template, 0.2 μmol/L primer, 2.25 mmol/L MgCl2, 0.6 U of Taq DNA polymerase, 0.4 mmol/L dNTPs. Proper annealing temperature was found at 48-50 ℃.The above system and six ISSR-PCR primers were used for the PCR amplification of 14 samples from Bryaceae and the related species in Mniaceae. A total of 86 bands were amplified, all showed polymorphism. NJ cluster analysis showed a star-shaped cladogram. [Conclusion] The results manifested that ISSR fingerprinting could provide the appropriate degree of polymorphism at low taxonomic level, so it would be a useful tool to provide additional evidence for resolving taxonomic relationships at the species level of Bryaceae.
基金supported by Natural Science Foun-dation of Hebei Province (D2006000701, C2007000247)Doctoral Fund of Hebei Normal University (L2008B11)
文摘A new breeding population of Mandarin Duck (Aix gaIericulata, Linnaeus) was first recorded in 2003 in Jiao- tanzhuang-Hehekou region of Pingshan county, Hebei Province, China. Recently, the gradually increasing population indicates that there are suitable breeding habitats (such as foraging habitats and nesting sites) for Mandarin Duck. However, these habitats are always close to human disturbances, which are the potential risk for their population. Therefore, it is urgent to put forward an applicable protection strategy, in order to strengthen the public awareness for this unprotected population.
文摘[Objective] The aim was to research balance between manure of breeding farm and farmland load. [Method] N balance of farmlands after manure fertilized was researched in a hoggery in Beijing (600 base sows and 647 breeding pigs). [Result] The suitable N input in neighboring farmlands was 191.9 kg/(hm 2 ·y) and the farmland area satisfying balance between growing and breeding was 53.7 hm 2 in the hoggery. [Conclusion] The research provided a scientific method for balance between growing and breeding.
文摘By field experiments with Uniform Design, the effects of planting density and nitrogen rate on three varieties (Yunrui No.8, Yunrui No.6 and Yunrui No.88) grain yield under different ecological conditions were studied in Yunnan Province. The results showed that the grain yields were different among the five experiment locations, when increasing of planting density, it did not affected the plant height, ear height and ear factor, with the planting density increased, stem diameter, leaf width, ear length, number of grains per row and 1 000-grain weight decreased sig- nificantly, but the grain yield of the third varieties increased. High planting density had a negative impact on ear traits, but the grain yield increased by high-density compensate for the adverse effects.Control space and time of fertilizer application can reach the highest yield under less Nitrogen fertilizer Yunrui 88 had the charec- teristics of wide range of adaptability and the density-tolerance, high-yielding poten- tial, which was favorable in planting on large areas.
文摘Total mercury concentration of typical wetland plants was analyzed in thispaper. There were great differences of total mercury concentration among different plants:moss>hydrophyte>sedge>herbage>shrub. Total mercury concentrations show an increasing trend fromvascular plants to bryophytes, and from dry to wet lands. The mercury concentration of wetlandplants was higher than that of crops. The wetland soil was the source of mercury in the air close tothe ground, so it affected the concentration of mercury in the plant. In different parts of aplant, mercury concentration was in the order of: dead stand>root>leaf>stem. Mercury concentrationincreased at the initial stage and decreased in the end of the growing season. According to themercury content and biomass, mercury stock of plants was 39.4μg/m^2 above ground in Calamagrostisangustifolia wetland and 35.8μg /m^2 in Carex lasiocarpa wetland.
文摘AIM: To investigate the effect of Mirtazapine on tumor growth, food intake, body weight, and nutritional status in gemcitabine-induced mild cachexia. METHODS: Fourteen mice with subcutaneous xenografts of a pancreatic cancer cell line (SW1990) were randomly divided into Mirtazapine and control groups. Either Mirtazapine (10 mg/kg) or saline solution was orally fed to the mice every day after tumor implantation. A model of mild cachexia was then established in both groups by intraperitoneal injection of Gemcitabine (50 mg/kg) 10 d, 13 d, and 16 d after tumor implanta- tion. Tumor size, food intake, body weight, and nutritional status were measured during the experiment. All mice were sacrificed at day 28. RESULTS: (1) After 7 d of gemcitabine administration, body-weight losses of 5%-7% which suggested mild cachexia were measured; (2) No significant difference in tumor size was detected between the Mirtazapine and control groups (P > 0.05); and (3) During the entire experimental period, food intake and body weight were slightly greater for the Mirtazapine group compared with controls (although these differences were not statistically significant). After 21 d, mice in the Mirtazapine group consumed significantly more food than control mice (3.95 ± 0.14 g vs 3.54 ± 0.10 g, P = 0.004). After 25 d, mice in the Mirtazapine group were also significantly heavier than control mice (17.24 ± 0.53 g vs 18.05 ± 0.68 g, P = 0.014). CONCLUSION: Mild cachexia model was successfully established by gemcitabine in pancreatic tumor-bearing mice. Mirtazapine can improve gemcitabine-induced mild cachexia in pancreatic tumor-bearing mice. It was believed to provide a potential therapeutic perspective for further studies on cachexia.
基金Supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (No. O72715)
文摘This paper reports for the first time a species of polychaetous family Paraonidae, Paraonella platybranchia (Hartman, 1961), a rare species found previously only in the coast near the boundary between the United States and Mexico, and it was recently discovered in the samples collected in 1982 from Chinese side of the Yellow Sea. This is the first record of the species in China as well as in the Northwest Pacific.
基金Supported by the National Natural Science Foundation of China(No.41076104)the Knowledge Innovation Program of the Chinese Academy of Sciences(No.KSCX2-YW-Z-0916)
文摘This paper describes a new species of Nassarius from the South China Sea,which was recognized when re-sorting the collection of Nassariidae in the Marine Biological Museum,Chinese Academy of Sciences,Qingdao,China.The shells were collected during several investigations,including the National Comprehensive Oceanic Survey in 1958-1959,and the China-Vietnam Co-Investigation on Marine Resource of the Beibu Gulf during 1959-1962.The morphology of the shell and the radula places the new species of Nassarius within the subgenus Zeuxis.It is named Nassarius(Zeuxis) nanhaiensis sp.nov.
文摘On the basis of population balance a mathematical model is developed to describe the formation of polymer particle in styrene suspension polymerization. The characteristics of coalescence and breakage of droplets and the gel effect are analyzed in particular. Parameters of the models are estimated by experimental data on reaction conversion and particle size distribution. The results show that the model is suitable for predicting polymerization processes.
基金Under the auspices of National Natural Science Foundation of China (No. 40971062)China Postdoctoral ScienceFundation (No. 20100480441)
文摘Based on the data from the Cost-benefit Data of Farm Produce and the China Agricultural Yearbook, this paper aims to examine the spatial and temporal change characteristics of total grain production and its affecting factors. The results show that: 1) During 1980 to 2007, total grain production increased from 3.20 ~ 108 t to 5.02 x 108 t in China, with annual increasing rate of 1.68%. From the regional disparities, most of the regions present increasing trend of total grain production except for several regions with higher level of economic development; 2) Grain sown area decreased from 1.17 × 108 ha in 1980 to 1.06 x 108 ha in 2007, which has negative effect on total grain production; 3) The increase of grain yield per unit area caused by land use intensity changes contributed to the increase of total grain yield greatly. However, as the land use intensity showed that farmers pay more attention to labor-saving input but not yield-increasing input, the less enthusiasm of farmers in grain production may become an important constraint on fu- ture grain production increase in China; 4) Based on the results, this paper proposed different land management poli- cies in different regions, for example, the government should protect cultivated land, promote large scale production. As to the less developed regions, the government should pay more attention to agricultural subsidies to promote farm- ers' enthusiasm in grain production.
文摘Unsystematic selection and planting of tree seedlings in road borders, forest regeneration, development of parks and green spaces which are incompatible with the given climate zone, is a kind of interference and violation of ecosystem privacy. Therefore, the stability and persistence of species in the forest protection is important for planners of natural resources. Field station of spreading Dehloran aquifer is one of the major forestations in Ilam province. It aimed of protecting the soil and underground water table feeding in hot dry plains of Mosian, which have been planted with native and non-native species. In the present article 100 trees of each species were planted during the years 1998 and 1999 in the station, such as Ziziphus spina-christi, Prosopis juliflora, Eucalyptus camaldulensis and Acacia sp. They were randomly selected and information about this species measured and recorded annually has been used. Finally the data has been analysis; by comparison test to compare the growth and persistence. Results indicate that despite high average in height growth (85.4 cm/year) and relatively large diameter growth (2.43 cm/year), non-native species of Eucalyptus are not in good condition in terms of viability (36.2 percent) and freshness. On the contrary, the native species of Ziziphus with relatively low in average height and diameter growth (22.64 and 2.28 cm/year respectively) represent a better index of viability (65.4 percent) and freshness.
文摘The Thai mahseer is one of the high-value freshwater fish species, especially m Malaysia where it is cultured commercially but poorly known in Thailand. This paper reviews a recent knowledge necessary for commercial culture of Thai mahseer based on the breeding and rearing practices in Malaysia. Breeding data shows that this species can be spawned all year round. On average, the size of mature female that can be induced to spawn is 678 mm total length (TL) and 3,817 g in weight and the size of mature male is 599 mm TL and 2,414 g in weight. Induced spawning using an analogue of sGnRH Ovaprim at 0.5 ml/kg body weight (BW) is the most successful hormone treatment and dosage for Thai mahseer. The average number of eggs is 875 egg/kg BW. Eggs of the Thai mahseer are spherical, demersal and non-sticky, and hatching occurs 69-90 hours post-fertilization. At 60 weeks of age, average body weight is 179 g. Polynomial regression analysis revealed a maximum specific growth rate at 48% dietary protein. General biology, water quality requirements, feeding strategies and genetic structure of the Thai mahseer are also summarized in this paper.
基金supported by the National Basic Research Program (973 Program 2010CB428902)the National Natural Science Foundation of China (40876088)
文摘Relatively short historical catch records show that anchovy populations have exhibited large variability over multi-decadal timescales.In order to understand the driving factors(anthropogenic and/or natural) of such variability,it is essential to develop long-term time series of the population prior to the occurrence of notable anthropogenic impact.Well-preserved fish scales in the sediments are regarded as useful indicators reflecting the fluctuations of fish populations over the last centuries.This study aims to validate the anchovy scale deposition rate as a proxy of local anchovy biomass in the Yellow Sea adjoining the western North Pacific.Our reconstructed results indicated that over the last 150 years,the population size of anchovy in the Yellow Sea has exhibited great fluctuations with periodicity of around 50 years,and the pattern of current recovery and collapse is similar to that of historical records.The pattern of large-scale population synchrony with remote ocean basins provides further evidence proving that fish population dynamics are strongly affected by global and basin-scale oceanic/climatic variability.