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51.
依据2004—2018年中国、越南木质家具出口数据为基础,应用社会网络分析方法、描述性统计分析法与修正的恒定市场份额模型(CMS),分析国际木质家具出口贸易格局、中国与越南木质家具出口波动的特征与成因。结果表明:中国木质家具出口波动大于越南,中国与越南木质家具出口结构相似,中国木质家具出口市场比越南更为分散。对中国、越南木质家具出口波动的影响,由大到小依次为竞争力效应、需求规模效应、结构效应。中国政府应加强政策导向,wood,增强抵御风险能力;中国企业应注重优化产业链,提升木质家具的产品竞争力。  相似文献   
52.
This study was conducted in 20 reservoirs, ranging in size from 4 to 30 ha, in the mountainous, northern region of Vietnam, in ThaiNguyen and YenBai provinces, over two growth cycles in 2002/03 and 2003/04. The reservoirs are leased by farmers for fishery activities from the provincial administration, and the trials were managed by the lessee farmers. Three species combinations in ratios (by fingerling weight) of grass carp: silver carp: bighead carp: common carp: mrigal 1:2:1:1:3 (A), 1:3:1:1:2 (B) and 1:2:1:1:2 (C) were used as seed stock. The overall mean yield of stocked fish in 2002/03 and 2003/04 growth cycles in reservoirs in ThaiNguyen and YenBai provinces was 165 (±21) and 190 (39), and 287 (±22) and 325 (±24) kg ha?1 respectively. The yield in reservoirs in both provinces, in both growth cycles and irrespective of the species combinations, increased in relation to stocking density. In reservoirs in ThaiNguyen Province, the species combination B gave the lowest yield (both growth cycles and overall), and differed significantly (P<0.05) from combinations A and C. The stocking efficiency (ratio of the yield of stocked fish in kg ha?1 to the weight of the stocked fish in kg ha?1) in reservoirs in ThaiNguyen Province ranged from 2.9 to 5.1 over the two growth cycles and that in YenBai from 2.8 to 3.9. There was no discernible trend between growth cycles and/or between species combinations. The major cost incurred was for fingerling procurement. In all instances, a net profit was accrued. The mean (±standard error (SE)) net profit ha?1 (in 103VN dong; approximately 15 500 VND=1 US$) was 885 (±270) and 864 (±214), and 1322 (±176) and 1600 (±150) for the growth cycles 2002/03 and 2003/04 for reservoirs in ThaiNguyen and YenBai provinces respectively. Between the two growth cycles, the net profit increased in eight and three reservoirs from YenBai and ThaiNguyen, respectively, the maximum increase being recorded in Khuan Gio (165%) and Dong Man (39%) reservoirs.  相似文献   
53.
Aquaculture of Spinibarbus denticulatus (Oshima, 1926), a fish species indigenous to North Vietnam and Eastern China, is constrained by lack of fingerlings for stocking ponds and cages. As these fish do not naturally breed in captivity, carp pituitary extract (CPE), luteinizing hormone-releasing hormone analogue (LHRHa) with domperidone (DOM) and human chorionic gonadotropin (HCG) were administered at various doses to induce ovulation. A first set of experiments evaluated the response to LHRHa (30, 40 and 50 μg kg−1) with or without DOM (10 mg kg−1), CPE (20, 30 and 40 mg kg−1) and HCG (3000, 4000 and 5000 IU kg−1). A second set of experiments evaluated the dose response to LHRHa (30, 35, 40 and 50 μg kg−1) primed with 6 mg kg−1 of CPE, and HCG (3000, 3500, 4000, 5000 IU kg−1) primed with 6 mg kg−1 of CPE. The treatment groups were compared with each other and the control (injected with 0.9% saline solution). Only 25% and 50% ovulation resulted when treated with LHRHa at 40 and 50 μg kg−1, whereas 100% ovulation was achieved with an addition of DOM to LHRHa. Both 30 and 40 mg kg−1 CPE induced 100% ovulation. However, HCG (4000 and 5000 IU kg−1) induced ovulation in only 33% of females. When primed with CPE, the minimum dose of LHRHa required was 35 μg kg−1 to achieve 70% ovulation. Priming HCG with CPE also resulted in 100% ovulation, and the minimum effective dose of HCG to induce ovulation was 3500 IU kg−1 with 60% ovulation. Fertilization and hatch rates observed in this study with different hormonal stimulation were high (80–93%). The results indicate that while the use of combined hormone strategy has no apparent advantage over a single hormone strategy, LHRHa+DOM (40 μg kg−1+10.0 mg kg−1) and CPE (30 mg kg−1) are most effective in consistently inducing ovulation and thus can be used for commercial hatchery production of S. denticulatus larvae.  相似文献   
54.
55.
Maintaining a liveable environment in Vietnam's polluted craft villages is a daily challenge for state authorities and residents. Neighbouring urban populations demand that the state effectively curtails and manages pollution, while local residents prioritise their livelihoods and routinely flout regulations. The commune official, tasked with the seemingly impossible task of environmental regulation, occupies a fraught position, torn between the imperatives and constraints of craft producers and state regulatory demands. This study of water pollution in northern Vietnam's craft villages finds that commune officials' conflicted role in environmental governance is a central factor in the failure of the current environmental governance regime, and reflects the internally conflicted nature of the Vietnamese state.  相似文献   
56.
This study evaluates smallholder pig production systems in North Vietnam, comparing a semi-intensive system near a town with good market access, where a Vietnamese improved breed has replaced the indigenous pig breed, and an extensive system away from town, where the indigenous breed still prevails. Fieldwork was conducted in 64 households in four villages. Repeated farm visits yielded 234 structured interviews. Data were analysed by linear models and non-parametric tests. Production inputs and outputs were quantified, and feed use efficiency and economic efficiency were assessed. The gross margin was higher for semi-intensive production with the improved breed, while the benefit–cost ratio was higher under extensive conditions with the indigenous breed. The net benefit did not differ between systems. Twenty-four per cent of farmers yielded a negative net benefit. In one village under extensive conditions, live weight output from indigenous sows with crossbred offspring compared positively with the output from semi-intensive production with improved genotypes, but was associated with high inputs, making production inefficient. Results indicate that improved genotypes might not be an efficient production alternative for saving-oriented production with limited resource supply. Suitability of evaluation parameters, farmers’ production aims, and factors impacting the production success in different systems are discussed.  相似文献   
57.
东南亚、南亚地区是世界上重要的稻米产区,稻米在民众饮食生活和国家社会政治中占有重要地位,民众生活中也保存了非常悠久和丰富的稻作文化习俗及稻谷起源神话传说。本文分析了水稻在东南亚、南亚主要国家印度、印度尼西亚、泰国、越南、菲律宾、孟加拉国、缅甸的作用、地位、生产、消费、文化等情况,并指出了印度、印度尼西亚稻文化的主要标志。  相似文献   
58.
缪苗  刘晃  张成林  陈军 《农学学报》2021,11(7):77-83
越南是“一带一路”沿线国家中唯一一个与中国海陆相连的国家。本文在实地调研的基础上,借助相关数据库,对越南渔业资源、产量规模、养殖和捕捞模式、水产品进出口贸易以及越南渔业管理架构、科研院所及渔业政策进行详尽阐释,分析越南渔业产业可持续发展的制约因素及中越渔业合作潜力,并结合当前形势下中越渔业产业发展及合作面临的挑战,提出加强数字政府引导助推水产业的恢复,加速水产业全行业的智能化和信息化,凭借电商平台整合产销对接,依靠互联网助力线上的洽谈与交流,秉承“搁置争议,面向未来,共同发展”的原则开展多领域多层次多渠道的合作,加强国际化复合型人才的培养的未来发展策略。  相似文献   
59.
Abstract

To evaluate arsenic (As) levels in agricultural soils of the Red River Delta in northern Vietnam, surface (0–5 cm) and subsurface (20–25 cm) soil samples were collected from 18 paddy and six upland fields on both sides of the river. As a reference, forest soils were also sampled at two sites of the upper river basin. The total As contents of approximately 80% of the surface paddy and upland soils exceeded the maximum allowable limit for Vietnamese agricultural soils (12 mg kg?1). Arsenic contents higher than 35 mg kg?1 were found in soils from the Hungyen and Hanam provinces, where high As levels in the groundwater have also been reported. Sequential fractionation of As in these soils indicated that the amounts of As in the phosphate-extractable and residual fractions were higher than those in the forest soils. Elevated total As contents were also detected in the surface soil of a paddy field near a fertilizer factory in Hanoi (site P10). The amount of HCl-extractable As in the surface soil at P10 corresponded to 84% of the total As, while the proportion never exceeded 40% at other locations. In the surface soil at P10, most of the As was part of the phosphate-extractable fraction. Significant correlations between the total As contents of the upland soils and their non-crystalline Fe oxide contents (r = 0.652, P ≤ 0.05) and between As levels of paddy soils and their crystalline Fe oxide contents (r = 0.544, P ≤ 0.01) were observed. Overall, the present study indicated that although serious As pollution was not found in the studied area, there were some point pollutions caused by industrial activities, in addition to some non-point pollutions resulting from high As concentrations in the groundwater. In addition, Fe oxides in the soils are important factors affecting the As contents of agricultural soils in the Red River Delta.  相似文献   
60.
Abstract

In Vietnam, the Co Dinh mine is the largest chromite mine in the country. Mining, ore dressing and disposal of the tailings provide obvious sources of heavy metal contamination in the mine area. The present study examined the influence of chromite mining activities on the adjacent lowland paddy field by investigating heavy metal and As levels in the mine tailings, sediments, paddy soils and water. At paddy fields located near the mine tailings, the total contents of Cr, Co and Ni were 5,750, 375 and 5,590?mg?kg?1, and the contents of their water-extractable form were 12.7, 1.16 and 32.3?mg?kg?1, respectively. These results revealed severe contamination of lowland paddy soils with Cr, Co and Ni as a result of mining activity, suggesting serious health hazards through agricultural products, including livestock in this area. The principal source of the pollution was sediment inflow owing to the collapse of the dike, which was poorly constructed by heaping up soil. Moreover, water flowing out from the mining area was also polluted with Cr and Ni (15.0–41.0 and 20.0–135?μg?L?1, respectively). This might raise another problem of heavy metal pollution of watercourses in the area, indicating the need for further investigation and monitoring of fluctuations of water quality with seasonal changes.  相似文献   
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