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951.
糖蜜酒精废水两相UASB处理工艺的酸化段特征 总被引:7,自引:0,他引:7
文章考察了糖蜜酒精废水二相UASB处理工艺的酸化段特征 ,试验结果表明酸化段的容积负荷达到3 0kgCOD/m3 时 ,系统仍能正常运行 ,TOC去除率在 3 5%以上 ,酸化段的SO4 2 -去除率在 70 %。糖蜜酒精废水酸化率在 50 % ,二相厌氧生物处理系统并未将产酸微生物与产甲烷微生物截然分开 ,在产酸相中仍含有一定数量的产甲烷菌。 相似文献
952.
对蕃茄基因转化的受体系统进行了研究结果表明:在蕃茄离体子叶(或子叶切段)培养中,只加细胞分裂素(Zt或BA)即可使不定芽充分分化,而少量生长素对不定芽的分化反而有抑制作用;在所试验过的多种外植体中,以2/3子叶片处切割子叶所产生的外植体用作转化受体最好;不同蕃茄品种、同一品种的不同外植体及同一外植体的不同培养方式等均对转化频率有一定的影响;通过生长素短期刺激诱导,可解决转基因植物生很困难的问题. 相似文献
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There is increasing recognition among conservation scientists that long‐term conservation outcomes could be improved through better integration of evolutionary theory into management practices. Despite concerns that the importance of key concepts emerging from evolutionary theory (i.e., evolutionary principles and processes) are not being recognized by managers, there has been little effort to determine the level of integration of evolutionary theory into conservation policy and practice. We assessed conservation policy at 3 scales (international, national, and provincial) on 3 continents to quantify the degree to which key evolutionary concepts, such as genetic diversity and gene flow, are being incorporated into conservation practice. We also evaluated the availability of clear guidance within the applied evolutionary biology literature as to how managers can change their management practices to achieve better conservation outcomes. Despite widespread recognition of the importance of maintaining genetic diversity, conservation policies provide little guidance about how this can be achieved in practice and other relevant evolutionary concepts, such as inbreeding depression, are mentioned rarely. In some cases the poor integration of evolutionary concepts into management reflects a lack of decision‐support tools in the literature. Where these tools are available, such as risk‐assessment frameworks, they are not being adopted by conservation policy makers, suggesting that the availability of a strong evidence base is not the only barrier to evolutionarily enlightened management. We believe there is a clear need for more engagement by evolutionary biologists with policy makers to develop practical guidelines that will help managers make changes to conservation practice. There is also an urgent need for more research to better understand the barriers to and opportunities for incorporating evolutionary theory into conservation practice. 相似文献
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C.R.M. Attard L.M. Möller M. Sasaki M.P. Hammer C.M. Bice C.J. Brauer D.C. Carvalho J.O. Harris L.B. Beheregaray 《Conservation biology》2016,30(5):1060-1069
Research in reintroduction biology has provided a greater understanding of the often limited success of species reintroductions and highlighted the need for scientifically rigorous approaches in reintroduction programs. We examined the recent genetic‐based captive‐breeding and reintroduction literature to showcase the underuse of the genetic data gathered. We devised a framework that takes full advantage of the genetic data through assessment of the genetic makeup of populations before (past component of the framework), during (present component), and after (future component) captive‐breeding and reintroduction events to understand their conservation potential and maximize their success. We empirically applied our framework to two small fishes: Yarra pygmy perch (Nannoperca obscura) and southern pygmy perch (Nannoperca australis). Each of these species has a locally adapted and geographically isolated lineage that is endemic to the highly threatened lower Murray–Darling Basin in Australia. These two populations were rescued during Australia's recent decade‐long Millennium Drought, when their persistence became entirely dependent on captive‐breeding and subsequent reintroduction efforts. Using historical demographic analyses, we found differences and similarities between the species in the genetic impacts of past natural and anthropogenic events that occurred in situ, such as European settlement (past component). Subsequently, successful maintenance of genetic diversity in captivity—despite skewed brooder contribution to offspring—was achieved through carefully managed genetic‐based breeding (present component). Finally, genetic monitoring revealed the survival and recruitment of released captive‐bred offspring in the wild (future component). Our holistic framework often requires no additional data collection to that typically gathered in genetic‐based breeding programs, is applicable to a wide range of species, advances the genetic considerations of reintroduction programs, and is expected to improve with the use of next‐generation sequencing technology. 相似文献
959.
Prenatal diagnosis of mosaicism involving an apparently unstable 13/14 Robertsonian trans-location is reported. This illustrates the difficulties encountered in counselling when mosaicism is ascertained prenatally. Other reported examples of apparently unstable Robertsonian translocations are discussed. 相似文献
960.
Dr Jean Cazenave LABM Francois Forestier Marie Hélène Bessieres Bernard Broussin Joël Begueret 《黑龙江环境通报》1992,12(2):119-127
A polymerase chain reaction (PCR) assay has been developed for the detection of Toxoplasma gondii. The target sequence (88 bp) is part of a rDNA repetitive gene. A signal can be observed with only one parasite. It is directly and rapidly detected by electrophoresis and ethidium bromide staining. We report a prospective study of 80 documented cases of toxoplasmic seroconversions during pregnancy. The PCR assay of the amniotic fluids was compared with the current standard methods for diagnosis of fetal infection. Seventy specimens gave no PCR signal, and were negative according to prenatal tests and postnatal examinations. The presence of T. gondii was detected in ten specimens by PCR analysis. Four were confirmed by isolation of the parasite from the amniotic fluid; four by biological study of the fetal blood. For the remaining two, infection was diagnosed after birth. Together with ultrasonographic and biological data, this technique permits prenatal diagnosis within 1 day. 相似文献