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Yea Hwang MOON Ji Un OK Shin Ja LEE Jong Kyu HA Sung Sill LEE 《Animal Science Journal》2010,81(6):642-647
A comparative study among Korean native cow (Hanwoo), Holstein dairy cow, Korean native goat and crossbred sheep on the population and marker concentration of ruminal microbes, the activities of carboxymethylcellulase (CMCase), xylanase and amylase, and in situ dry matter (DM) degradability were conducted. Twelve ruminally cannulated animals, three of each species, were used. Animals were fed the same diet containing 40% formula feed and 60% rice straw at the level of 2.5% of body weight. Total viable microbial populations in the rumen fluid were significantly (P < 0.01) greater for bacteria and fungi in goat than those of Holstein. The protozoan population among ruminant species was the reverse from that of bacteria. The concentrations of 2,6‐diaminopimelic acid and chitin as markers for bacteria and fungi in the rumen fluid, respectively, were highest in goat, which is in accordance with the above population data. The concentration of aminoethylphosphonic acid as marker of protozoa was highest in Hanwoo and lowest in sheep (P < 0.01). Goat had the highest (P < 0.01) activities of all the enzymes investigated among ruminants. In situ effective degradation of the DM of rice straw was approximately 19% higher in the rumen of goat compared with other animals. 相似文献
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Questions surrounding the impact of population migration on social capital is the focus of this study. Putnam observed that “for people as for plants, frequent repotting disrupts root systems. It takes time for a mobile individual to put down new roots.” However, because of a trending decrease in mobility over time, Putnam rules out migration as an explanation for the long‐term decline in social capital that was the subject of his widely read 1995 book Bowling Alone: America's Declining Social Capital. This study undertakes an empirical examination of the impact of migration on county‐level social capital, which in tribute to Putnam one might view as an attempt to answer the question—do migrants take their bowling balls with them when they move? The potential for county‐level migration of population to impact social capital levels at particular locations in space arises from the conventional argument that social capital promotes trust and cooperation among agents. This trust increases socially efficient collective action but requires investment in relationships and commitment of scarce resources to build social capital. It seems plausible that migration of population might have a negative impact on the stock of social capital by interfering with trust and cooperation among agents. However, it is also possible that migrants may take their social capital with them to new places of residence. In other words, the propensity to join social and civic organizations might reflect inherent traits of individuals who are willing to make commitments of their resources to building social capital in any community where they reside. 相似文献
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玉米多胞质雄性不育杂交种冀玉988的选育及利用 总被引:2,自引:0,他引:2
不育化制种主要在于保证杂交种子的质量及降低其生产成本。多胞质杂交种的利用主要拓宽胞质异质性,增强杂交种对环境的适应能力与防范小斑病菌新的专化小种的严重为害。本研究以优良玉米新品种冀玉988(6048×黄选921.6)为背景,以s组的s,M,R与21A及C组的Rb,Bb与Es雄性不育细胞质(CMS)为试材,将母本6048转育成同核异质体,不育性稳定。父本921.6对21A,s与R三种CMS具有强恢复性。本研究论证了多胞质杂交种在生产上利用的可行性。冀玉988已配制成具有恢复性能的多胞质雄性不育杂交种,可用于生产。 相似文献
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[目的]对典型干旱区绿洲城市新疆喀什市近20a来的乡村转型发展进行研究,评价当地的乡村转型发展程度及土地利用变化对乡村转型发展的影响。[方法]构建乡村转型度、城乡协调度两个评价体系,利用TOPSIS法量化喀什市1995—2015年乡村转型发展变化,通过Pearson相关分析法得出影响乡村转型发展程度的因子。[结果]喀什市乡村转型度在整体上处于上升态势,速率较慢,年际变化率为0.55%/a,城乡协调度在整体上处于微弱下降态势,年际变化率为-0.06%/a,近20a来喀什市乡村转型发展经历了低速—协调、中速—较协调、中速—不协调、高速—不协调、中速—协调5个阶段,乡村转型发展水平综合指数逐年上升,增率为0.31%/a,影响喀什市乡村转型发展的主要因子包括农业人口比重、乡村人均GDP、农民人均纯收入、第一产业劳动率及乡村污染物处理率。[结论]农业人口比重在数量上与乡村转型发展度的耦合度达0.786,农业人口比重在质量上与乡村转型发展度的耦合度达0.559,乡村人均GDP比重变化与乡村转型发展度的耦合度达0.877耕地转为建设用地的面积比重变化与乡村转型发展度的耦合度达0.641,喀什市的乡村转型发展与人口转型、经济转型、土地利用方式转型的一致性较高,属于良性的转型发展。 相似文献
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