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We investigated the effect of raising runt white sturgeon (Acipenser transmontanus) separately from dominant fish during the initial stages of grow-out in a commercial farm. Runt fish are poor-growers, have underdeveloped muscle mass, swim slowly and are more-frequently found at the top of the water column. The objective of the study was to describe the mortality and recovery rates (and their determinants) of white-sturgeon runts after separating them from dominant fish. Runt white sturgeon were stocked into twelve 2 m × 2 m rectangular tanks and graded periodically during a follow-up of 46–102 days. Overall mortality rates ranged from 0.3 to 7 dead fish per 1000 sturgeon-days at risk and overall recovery rates from 3.9 to 13.5 recovered fish per 1000 sturgeon-days at risk. Period-specific mortality and recovery rates increased over time. The period-specific mortality rates for all three periods were significantly higher for tanks of runts originating from grow-out tanks with high mortality (p-values: first period = 0.06; second period = 0.09; third period = 0.03), but were similar for tanks of runts of high- and low-mean initial weight. The period-specific recovery rates were significantly higher in runts originating from high-mortality grow-out tanks only for the third period (p = 0.05) but not the first and second periods (p-values = 0.33 and 0.25, respectively). Recovery rates were significantly higher in the higher-mean-weight runts tanks for the first and third period but not for the second (p-values: first period = 0.02; second period = 0.65; third period = 0.06). We concluded that the proportion of runts that recover during a 46–89 day period is substantial (16–58%); therefore, it might be worthwhile growing such fish separately in a fish farm for about three months. Financial analysis showed that this practice was profitable, if the value of white sturgeon fish for the farm exceeded $2.05 per kg. 相似文献
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Our study area in the Chaobai watershed, upstream of Miyun Reservoir, has been undergoing agricultural water transfers to downstream municipal uses in Beijing. We examine the impacts of water reallocation on crop production and farmers’ income and discuss issues relating to current compensation mechanisms. We use data from a survey of 349 farm households and their farm plots in the upper Chaobai watershed within Hebei province. Water reallocation from upstream to downstream areas has reduced agricultural water supply and the area irrigated. Regression results show that in plots deprived of irrigation, maize yields decrease by 21% and crop revenues decline by 32%. On average, losing irrigation on one hectare of cultivated land reduces net crop income by 2422 yuan. We examine compensation arrangements and social equity for the major policies implemented in the region and we identify gaps between current compensation levels and farmers’ income and production losses. The current compensation received by farmers is generally lower than the losses incurred due to reduced irrigation. A more appropriate compensation mechanism is called for in future water transfers. 相似文献
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我国是农业大国,但由于经济起步较晚,农业发展相对落后,农民的受教育程度普遍较低,农户在从事家庭生产经营中难以运用科学的经济管理方式,尤其在财务管理方面。对农户家庭经营财务管理方面进行了简单分析,并提出了一些建设性意见。 相似文献
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本文在阐述负债经营为企业带来诸多经济利益的同时,也阐述了它给企业带来的财务风险。控制财务风险的关键在于把握负债经营的适度性。为此,着重论述企业如何通过财务管理手段,并运用一系列财务指标的计算、预测和分析,确定负债经营的最佳度,尽可能地降低负债经营的财务风险 相似文献
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基于对广西田东县实地调研的基础上,对其金融服务带动模式进行分析,总结了该模式的特点及取得的成效,并立足田东县的实际情况指出了金融服务带动模式存在的问题,提出相关政策建议. 相似文献
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阐述了农民专业合作社发展过程中财务管理方面存在的问题,分析了其产生的原因,论述了规范农民专业合作社财务管理的必要性,提出了完善农民专业合作社财务管理的若干对策与建议. 相似文献
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张军华 《湖南农业大学学报(自然科学版)》2014,(3):80-86
以2004~2011年沪深A股上市公司为样本,研究权益资本成本的行业差异以及行业特征对权益资本成本的影响。研究发现:行业门类层面和制造业次类层面的权益资本成本差异显著,这种差异在时序上较为稳定。行业竞争程度越低,权益资本成本越小,体现了产品市场竞争的特质性风险效应,行业收益波动和行业成长性分别对权益资本成本产生显著的正向影响和负向影响。企业会计准则的改革强化了行业因素对权益资本成本的影响。 相似文献
30.
提出了一种基于灰色-ARIMA的金融时间序列智能混合预测模型。首先建立金融时间序列灰色预测模型,并采用PSO算法对灰色模型的三个参数进行优化;利用ARIMA算法对预测模型的残差进行分析,同时采用遗传算法对ARIMA的系数进行优化;最后用ARIMA的残差预测结果对灰色预测模型进行补偿。结果表明,以较好的精度拟合一段时期内MA<107的时间序列,预测误差控制在5%以上,与单纯的灰色预测算法和神经网络算法相比,在平均绝对误差、均方根误差和趋势准确率三项评价指标上,具有明显优势。 相似文献