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1.
Abstract. This paper summarizes the economic aspects of production models and discusses the economic feasibilities and some marketing requirements of a proposed fisheries-aquaculture development at an ox-bow lake, isolated from the Perak River, at Teluk Intan, Perak, Malaysia. Measures of feasibility from a budgetary simulation model are expressed in terms of net present values of return (NPV), internal rate of return (IRR) and return on sale; their changes recalculated in relation to practical ranges of variations in sale prices and yields, and under conditions of normal and 20% increment in operational costs, are also expressed. Using appropriate real production data, the cage culture complex has an NPV of M$4.068 million with an IRR of 68% and return on sales of 31% at a sale price of M$10/kg and yield of 12kg/m3 (US$1.00 = M$2.30); capture fisheries integrated with livestock have an NPV of M$252410, IRR of 42% and return on sales of 18% at a sale price of M$2.50/kg and yield of 33 tonnes; the hatchery facility has an NPV of M$0.963 million, IRR of 38% and return on sales of 20% at a sale price of M$0.39/fry and yield of 2 million; and prawn pond culture has an NPV of M$314000, IRR of 43% and return on sales of 36% at a sale price of M$11/kg and yield of 2.5 tons/ha. Overall, the modular project has an NPV of M$5.596 million with an IRR and return on sales of 53% and 28% respectively. Should the operational costs increase by 20% above normal, project unviabilities are obvious at specific levels: cage culture is unviable at sale prices ≤M$8.00/kg and yields ≤10 kg/m3; capture fisheries at sale prices ≤M$1.5/kg; hatchery facility at sale prices of fry ≤M$0.30/fry; prawn culture at sale prices ≤M$8.00/kg and yields ≤2 tons/ha; and the overall project is unviable when the sale level of fisheries products drops to 80% of the normal and operational costs increase to 120%. With greater efforts at raising sales and securing better prices, and raising yields while reducing operational costs, the projects have a markedly improved economic profit. 相似文献
2.
为探讨育珠对壳基质蛋白基因表达的影响,开展了合浦珠母贝（Pinctada fucata）N19和Prismalin-14基因在育珠贝和非育珠贝中的荧光定量表达研究。结果显示,N19和Prismalin-14在育珠贝与非育珠贝的闭壳肌、肝胰脏、性腺、肠、鳃等组织中均无表达,在外套膜均有表达;N19在珍珠囊表达,而Prismalin-14则不表达。N19勺Prismalin．14在育珠贝外套膜的表达量均大于非育珠贝,表明育珠可能对某些壳基质蛋白的表达具有一定的促进作用。其中Prismalin-14在育珠贝外套膜的表达量最高（P〈0．01）,是非育珠贝外套膜Prismalin-14的1．23倍,是育珠贝外套膜N19的25．04倍,是非育珠贝外套膜N19的41．04倍,推测在珍珠贝生长过程中,对Prismalil7-14的需求量可能比N19大。N19在育珠贝珍珠囊中表达量最高（P〈0．01）,是育珠贝N19外套膜的11．58倍,是非育珠贝外套膜的18．97倍,推测在珍珠形成的过程中,对N19的需求量可能比贝壳自身生长对N19的需求量大。 相似文献
3.
遥感监测旱情的研究进展 总被引：20，自引：1，他引：20
干旱是威胁我国及世界农业发展的自然灾害之一，遥感技术已经成为监测旱情的重要手段。本文回顾了近些年来遥感监测旱情的研究进展，并总结了国内外常用的模型，着重从热惯量法，冠层温度法，植被指数法以及微波遥感等几方面做出评述，并对遥感监测旱情的下一步发展提出展望。 相似文献
4.
钟有为 《安徽农业大学学报》2005,(5):16-19,23
中国20多年发展的历程表明:中国己经走上“和平崛起”之际。中国为“和平崛起”正倡导并形成一整套适应世界潮流的国际关系新理念，即和平与发展的时代观以和为贵”、“和而不同”的文化价值观、互信互利平等协作的新安全观、公正合理的国际新秩序观，异国际关系民主化以及“以邻为伴”、“与邻为善”的新睦邻政策.在这些国际关系新理念支撑下正在崛起的中国就能够使世界各国充分相信中国是在维护世界和平中发展自己，并以自身的发展来促进世界和平。 相似文献
5.
RM ONG JP MORRIS JK O'DWYER JL BARNETT PH HEMSWORTH IJ CLARKE 《Australian veterinary journal》1997,75(3):189-193
Objective To measure acute pain in sheep, based on a human pain model, and examined changes in both electroencephalogram frequency spectrum and behavioural responses to increased electrical stimulation in sheep. Design Analysis of variance (treatment and animal effects) for stimulus intensity where each animal received each electric shock treatment given in the order 0, 5,10 and 20 mA. Procedure Eight sheep with electrodes implanted over the surface of the brain were examined for escape-avoidance and electroencephalogram responses to four levels of electrical stimulation from 0–20 mA. Results With increasing stimulus intensity at the time of feeding, the sheep were more hesitant to return to the feeder or remain near the feeder following stimulation. There was little difference between the 0 and 5 mA stimuli for any of the behaviour variables (P > 0.05). However, there were marked increases in the time taken to re-approach the feeder after receiving an electric shock of 5 mA and of 20 mA (P < 0.05; mean values 3 and 119 s, respectively) and remaining near the feeder for 5 s (P < 0.001; mean values 10 and 167 s, respectively). Following the stimulus, there was an overall increase in the electroencephalogram power spectrum in the first four seconds, which then rapidly returned to normal. In particular, the 20 mA stimulus resulted in higher absolute power values than in the control (0 mA) treatment for delta 2 (P < 0.001), theta 1 (P < 0.05), theta 2 (P < 0.05), alpha 1 (P < 0.001), alpha 2 (P < 0.001) and beta 1 (P < 0.01) band-widths. Similarly, for the 10 mA stimulus, the absolute power values were greater than the control treatment for delta 2 (P < 0.05), alpha 1 (P < 0.01), alpha 2 (P < 0.001) and beta 1 (P < 0.01) bandwidths. Conclusion The experiment suggests that a human acute pain model is applicable to sheep and that these electroencephalogram changes may provide a good measure of acute pain in sheep. 相似文献
6.
The causes of tiller death in a 2-year-old perennial ryegrass sward were examined between April and August 1977. Physiological causes accounted for most tiller deaths and grazing by slugs and rodents was more important than the damage caused by stem-boring larvae. Tillers which died were mainly small and vegetative, although some flowering tillers died prematurely. Low nutrient status delayed but did not prevent tiller death. Using 14CO2 it was shown that small tillers fixed relatively less radiocarbon than did larger tillers and they did not receive much support for their carbon economy. Selective defoliation showed that in April defoliated tillers imported radiocarbon from undefoliated tillers but that in July at anthesis an undefoliated reproductive tiller retained most of the carbon it fixed, despite its vascular association with defoliated tillers. It appears that much of the tiller death during the period April-August is due to the failure of the more favourably placed tillers to support other tillers which are heavily shaded. 相似文献
7.
The effect of nutrient concentration on the reproductive development and seed yield of Poa annua was examined in a sand culture experiment. The nutrient concentration during the initial vegetative stage did not affect the time taken for double ridge formation by the main shoot but did influence the subsequent development of the inflorescence as did the post-initiation level of nutrients. At low nutrient levels flowering was inhibited in some individuals but at the higher concentrations inflorescence emergence was hastened, inflorescence size was increased and, in particular, the number of spikelets and hence the number of seeds per inflorescence was greatly increased. The mean weight of 100 seeds was unaffected by the nutrient concentration. The number of reproductive tillers per plant was increased by high nutrient supply but the proportion of dry weight allocated to root development was reduced. 相似文献
8.
The physiology of tiller death in grasses. 总被引：2，自引：0，他引：2
C. K. ONG 《Grass and Forage Science》1978,33(3):197-203
A reproducible method of causing tiller death on individual ryegrass (Lolium perenne L., cv. S23) plants is described. This was achieved by subjecting whole plants grown previously for 7 weeks in full light (100%) and full nutrient (100%) to either light stress (17.5% or 2.5%) or nutrient stress (10% or 0%) or various combinations of light and nutrient stress. Detailed records were made of tiller appearance, position and weight, and the probability of tiller death was calculated. Analysis of each plant indicated that the smallest tiller, which was often, but not always the youngest, was the most vulnerable when the whole plant was stressed. Tiller position was relatively unimportant in determining survival. The results are discussed in relation to tiller mortality in natural populations and crop communities. 相似文献
9.
【目的】了解不同披碱草种质性状,为优良披碱草种质材料筛选提供依据。【方法】以21份不同来源的披碱草种质为材料,通过测定17个农艺指标,利用相关性分析、主成分分析、多元逐步回归分析、聚类分析等统计分析方法,研究披碱草主要农艺性状的变异特征,明确披碱草产量形成的主要影响因子。【结果】披碱草农艺性状变异丰富,变异系数在11.07%（花序长）～45.53%（基部茎长）。相关性分析表明,披碱草单株干草产量与基部茎长、旗叶长呈显著正相关（P<0.05）,单株种子产量与分蘖数、千粒质量呈极显著正相关（P<0.01）。多元逐步回归与通径分析表明,株高、茎粗、基部茎长、穗下茎长、旗叶宽、倒二叶长、倒二叶叶鞘长、倒二叶宽、花序长、小穗长、茎叶比是影响单株干草产量的主要因子,其中茎粗、基部茎长、穗下茎长、旗叶宽、倒二叶叶鞘长、小穗长、茎叶比对单株干草产量的影响有直接效应;株高、倒二叶叶鞘长、小穗长、分蘖数、千粒质量是影响单株种子产量的主要因子,其中小穗长、分蘖数对单株种子产量的影响有直接效应。主成分分析表明,前5个主成分累积贡献率达79.304%。根据第1,2主成分筛选出PJC09、PJC14、PJC15、PJC17、PJC18、PJC26、PJC27共7份单株干草产量和单株种子产量表现均较高的披碱草种质材料,其平均单株干草产量为197.02 g,单株种子产量为21.39 g。聚类分析表明,21份披碱草种质材料被聚为3类,第Ⅰ类包含2份种质材料,可作为筛选单株种子产量高的种质利用,第Ⅱ类包含10份种质材料,可作为筛选单株干草产量和单株种子产量均高的种质利用,第Ⅲ类包含9份种质材料,可依据育种目标筛选特异性状的种质利用。【结论】确定了11个影响披碱草单株干草产量的主要因子和5个影响单株种子产量的主要因子,筛选出单株干草产量和单株种子产量均表现优异的7份披碱草种质材料。 相似文献
10.
指出了宁波市耕地安全的主要问题,并运用人均占有耕地面积、人均耕地后备资源量、耕地补充系数和耕地质量指标等4项指标进行了耕地的安全评价,结果表明：除耕地质量指标大多能达到安全或高度安全状态外,其余指标都处于值得关注状态以下,尤其是受污染比例指标和人均耕地面积指标属于高度危险状态和危险状态。为提高耕地的安全性程度,必须建立地区性的耕地安全体系,实现耕地可持续利用。 相似文献