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1.
ABSTRACT: Experimental insemination was performed using artificially produced low-motility sperm. A mathematical model was applied to the results of the insemination in order to clarify the relationship between sperm motility, the density of sperm and the fertilization rate of eggs. In the model, the probability of fertilization by individual spermatozoa was a function of sperm density in the insemination solution. The results showed that the probability of fertilization clearly decreased with increased sperm density, and the maximum possible fertilizing rate by increasing the sperm density was constrained by the proportion of motile sperm (% motility). The model was also applied to the results of insemination tests of cryopreserved sperm in order to evaluate the fertilizing capacity of cryopreserved sperm. It was proven that cryopreserved sperm needed a higher density to obtain the maximum fertilization rate compared with fresh sperm, and it was anticipated that the ratio of the motile inseminated cryopreserved sperm should be more than 5.0% to achieve an egg fertilization rate greater than 90%. 相似文献
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Sakai Toru Omori Keisuke Oo Aung Naing Ma Swe Swe Zaw Yan Naung 《Paddy and Water Environment》2021,19(2):295-306
In the last 40 years, the rice-cropping system has considerably changed in the Ayeyarwady Delta. The large archive of satellite imagery provides a history of how land and water resource managements have changed in the face of growing populations, resource demand, and climate change. This study aimed to assess the decadal changes in the rice-cropping system in the Ayeyarwady Delta by using the large archive of satellite imagery for the last 40 years (1981???2020). The long-term NDVI dataset provided various information on rice cultivation. Signal processing techniques were used to detect on the historical changes in the rice-cropping system, and the impact of climate change was assessed by using trend analysis. Until the 1980s, single-cropping of summer rice was dominant in the Delta. To enhance the grain yield of rice, the irrigation facilities were introduced in 1992 under an initiative of the Myanmar government. As a result, the annual cropping intensities increased from 1.087?±?0.390 in the 1980s to 1.422?±?0.499 in the 2010s. The information on historical change in the rice-cropping system would be useful to consider the practical and cost-effective utilization of remaining land and water resources. Moreover, the trend analysis of NDVI time-series showed negative trends in coastal areas. This indicates that the rice production in coastal areas has been constrained by the saline intrusion. The salt-affected areas are expected to expand under future climate change scenarios. Government support is highly required for sustainable rice production in the Delta.
相似文献3.
He Qiang Lee Tae-Rim Yu Jie Oo Win Htet Yoon Min-Young Min Myeong-Hyeon Chu Sang-Ho Kim Kyu-Won Lee Young-Sang Park Yong-Jin 《Journal of Crop Science and Biotechnology》2020,23(1):9-20
Journal of Crop Science and Biotechnology - Fatty acids (FAs) are important desirable compounds in oil crops. Here, we evaluated the amounts of 14 FAs in sesame grains using gas chromatography mass... 相似文献
4.
Wheat yellow dwarf disease (BYD), caused by different species of barley/cereal yellow dwarf viruses (B/CYDVs), is one of the most serious cereal diseases in China and the Czech Republic. Because genetic diversity of the virus directly influences disease epidemiology, the molecular diversity and population structure of 24 Chinese isolates and 16 the Czech Republic isolates of BYDV-PAV from different regions in two countries were analyzed by sequencing their coat protein (CP) and readthrough protein (RTP) domain (RTD) genes and comparing the sequences with six CP and 16 RTP sequences of BYDV-PAV isolates from the NCBI database based on nucleotide identity position, phylogenetic analysis and nucleotide diversity. Nucleotide identities between the Chinese and the Czech Republic isolates for the CP were 76.6–99.4%, 73.9–89.1% for RTD (ORF5), respectively. The Chinese and the other country isolates showed 74.7–99.2% nucleotide identity for RTP (ORF3+ORF5). Phylogenetic analysis of CP sequences showed that 20 Chinese isolates clustered in the same clade, but the other four Chinese isolates clustered in another clade with the isolates from the Czech Republic and other counties. The population of BYDV-PAV in China had greater nucleotide variability and was more divergent than that in the Czech Republic. Geographical and ecological factors but not hosts might contribute to the population differences in the two countries. 相似文献
5.
Sakai Toru Omori Keisuke Oo Aung Naing Zaw Yan Naung 《Paddy and Water Environment》2021,19(2):283-294
Paddy and Water Environment - Summer rice cannot be grown near the coast of the Ayeyarwady Delta, Myanmar, because of the high salinity in river water during the dry season. This means that saline... 相似文献
6.
Daniel Basalirwa Shigeto Sudo Cosmas Wacal Aung Zaw Oo Daisuke Sasagawa Sadahiro Yamamoto 《Soil Science and Plant Nutrition》2020,66(2):328-343
ABSTRACT Biochar can reduce N2O emissions and it can be added to the soil once, whereas fertilizers are often applied every cultivation season. The aging of biochar in soil affects its functioning but it is unclear whether palm shell biochar (PSB) could still mitigate N2O emissions even when additional basal N fertilizers are applied 1 year after the initial biochar application. We studied the impact of fresh and aged PSB (0%, 6%, 12%, and 18% w/w of dry soil) on N2O emissions, soil properties, nutrient content and yield of Komatsuna (Brassica rapa var. perviridis) under sandy soil conditions. The aged PSB non-significantly reduced N2O emissions but significantly offset soil acidification, and maintained a high soil nutrient status. Biochar application with fertilizer significantly increased plant tissue K and Ca content but decreased N, P and Mg content compared to the treatments without biochar. At higher application rates, biochar had negative effects on crop yield but as it aged, the negative effects were offset as a result of the similar variation in plant N uptake. Since seasonal N fertilizer application seems to be inevitable in Komatsuna cultivation, addition of biochar could be a possible way of counteracting the effects of excessive fertilizer use. Further research is needed to assess the feasible biochar application rates for Komatsuna fields in various soil types under field conditions. 相似文献
7.
Myanmar is home to Asiatic black bears and sun bears. We gained insight into illegal hunting and trade of these species in and out of Myanmar through conversations with 40 self-declared bear poachers. All respondents were males who typically killed or caught one to three bears a year, mostly by setting snares. There was a preference for Asiatic black bear. Perceptions were that bears were less abundant now than 5 years ago, but it was not more arduous to obtain one. Most poachers (75%) consumed less valuable parts and sold the remainder, whereas others trapped only to sell. Preferred tradable parts were gall bladder, meat, and paws. Chinese nationals or Burmese of Chinese descent were mentioned as playing key roles (ordering, buying, selling) in trade. Instead of focusing on poachers, we recommend that authorities focus on disrupting trade networks and markets. Cooperation with neighboring countries, especially China, is needed to stem the flow of bear parts. 相似文献
8.
Optimization of Phosphorus Fertilizer in Supplemental Feed‐Fed Based Nile Tilapia (Oreochromis niloticus) Ponds 
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下载免费PDF全文 Moe Thidar Oo A M Shahabuddin Dhirendra P Thakur Aye Aye Mon Amararatne Yakupitiyage Amrit N Bart Ram C Bhujel Jim S Diana 《Aquaculture Research》2015,46(12):2859-2870
An experiment was conducted in earthen ponds at the Asian Institute of Technology, Thailand to determine different phosphorus fertilizer dose effects on Nile tilapia production, water quality variables, nutrient utilization and cost‐benefit under supplemental feeding. Five phosphorus fertilization rates were used as treatments e.g. 100%, 75%, 50%, 25% and 0% of 7 kg P ha week?1. Nitrogen fertilization rate was fixed at 28 kg N ha week?1 for all the treatments. Sex‐reversed Nile tilapia were stocked at 3 fish m?2, and 30% CP floating feed fed at 50% satiation feeding rate. Nutrient budget showed higher phosphorus fertilizer input resulted in higher phosphorus sink in the sediment. Mean weight, mean weight gain, daily weight gain and net yield were not significantly different among treatments (P > 0.05). Total Kjeldahl nitrogen, total phosphorus and soluble reactive phosphorus were significantly different among treatments. Economic analysis showed phosphorus fertilization resulted in positive net returns. Though the gross income was not affected by different fertilization rates, significantly lowest cost was found in the treatment using 25% phosphorus fertilizer. It can be concluded from the research that 25% phosphorus fertilization might be used as an alternative strategy of Nile tilapia pond culture in terms of economic return and nutrient loss in sediment. 相似文献
9.
Zaw Win Tu Tu Campbell Angus Soares Magalhães Ricardo J. Oo Kyaw Naing Henning Joerg 《Tropical animal health and production》2019,51(3):643-654
Tropical Animal Health and Production - The central dry zone of Myanmar is the area with the highest density of small-scale livestock farmers under harsh environmental condition. In this study, we... 相似文献
10.
G. Tondi C.W. Oo A. Pizzi A. Trosa M.F. Thevenon 《Industrial Crops and Products》2009,29(2-3):336-340
Tannin based rigid foams are structures in which flavonoids are randomly cross-linked with furanic units throughout covalent bonds. The use of these aromatic substrates from natural materials to trap some heavy metal ions dissolved in water solutions is described. Interesting results have been achieved using different mimosa bark tannin (Acacia mearnsii formerly mollissima, De Wildt) and pine bark tannin (Pinus radiata) mixed foams. Capability to catch Pb2+ and Cu2+ ions at different concentrations has been verified throughout ICP-OES analysis of the foams. A reliable proportionality has been found between initial concentration and percentage of metal ions adsorbed. These foams were able to adsorb up to 12.5% of Cu(II) and 20.1% of Pb(II) with respect to the concentration of these ions in solution. 相似文献