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1.
Comparative mapping of QTLs for Al tolerance in rice and identification of positional Al-induced genes 总被引：2，自引：0，他引：2
INTRODUCTION Aluminum (Al) toxicity is one of the mostimportant yield-limiting factors for crop grown onacid upland and lowland acid sulphate soils (IRRI,1978). Al toxicity results in a reduced and damagedroot system, which in turn causes the affectedplants to be susceptible to drought stress and min-eral nutrient deficiencies (Foy, 1988). The physio-logical and biochemical mechanisms of the toxiceffect of Al on root elongation had been extensivelyinvestigated (Matsumoto, 2000). T… 相似文献
2.
Kevin H. Ashford-Rowe Marnie Holt 《美中教育评论》2011,(3):317-322
The ＂emerging educational institutional decision-making matrix＂ is developed to allow educational institutions to adopt a rigorous and consistent methodology of determining which of the myriad of emerging educational technologies will be the most compelling for the institution, particularly ensuring that it is the educational or pedagogical but not the technological imperative that drives the technology integration agenda. The matrix is designed to be used after some initial research into an emerging technology. Once a technology is put through the matrix, a member of options are available： （1） shelving the technology; （2） putting the technology on hold and maintaining a watching brief until the technology matures in the market; and （3） researching the product further by conducting a trial or placing in testing sandpit. After further research, the technology can be tested as a pilot to determine how well or otherwise, the technology works within the institution. If an emerging technology has more than one product associated with it, a second and third step in the matrix has been developed, and the second step assigns a rating to each of the categories within the matrix. With many products containing similar features, a third step has been developed to compare products on a feature level. 相似文献
3.
Nazir Hawi 《美中教育评论》2010,7(9):47-57
The author has undergone a major shift in the way of teaching his undergraduate computer programming courses. In the classroom, the teacher＇s computer is connected to a splitter and a video projector that display the computer＇s screen to the entire class. Using this technology, the programming language itself is used live in class to help the students learn how to program. The students are learning in a context by far livelier than those of previous methods. Teaching computer programming is not achieved by lecturing and writing the program instructions on board or by displaying program instructions to the class on transparencies or slides of electronic presentations. With the implementation of student-centered approaches, the students migrated from the state of passive receivers to constructors of computer programming concepts. Students are coached to develop a sense of exploration, individuality and autonomous thinking. The enthusiasm for technology has been facilitating and supporting the learner-centered approach. Everyone in this approach is a learner, including the teacher. 相似文献
4.
Assessing potential dietary toxicity of heavy metals in selected vegetables and food crops 总被引：3，自引：0，他引：3
Heavy metals, such as cadmium, copper, lead, chromium and mercury, are important environmental pollutants, particularly in areas with high anthropogenic pressure. Their presence in the atmosphere, soil and water, even in traces can cause serious problems to all organisms, and heavy metal bioaccumulation in the food chain especially can be highly dangerous to human health. Heavy metals enter the human body mainly through two routes namely： inhalation and ingestion, ingestion being the main route of exposure to these elements in human population. Heavy metals intake by human populations through food chain has been reported in many countries. Soil threshold for heavy metal toxicity is an important factor affecting soil environmental capacity of heavy metal and determines heavy metal cumulative loading limits. For soil-plant system, heavy metal toxicity threshold is the highest permissible content in the soil （total or bioavailable concentration） that does not pose any phytotoxic effects or heavy metals in the edible parts of the crops does not exceed food hygiene standards. Factors affecting the thresholds of dietary toxicity of heavy metal in soil-crop system include： soil type which includes soil pH, organic matter content, clay mineral and other soil chemical and biochemical properties; and crop species or cultivars regulated by genetic basis for heavy metal transport and accumulation in plants. In addition, the interactions of soil-plant root-microbes play important roles in regulating heavy metal movement from soil to the edible parts of crops. Agronomic practices such as fertilizer and water managements as well as crop rotation system can affect bioavailability and crop accumulation of heavy metals, thus influencing the thresholds for assessing dietary toxicity of heavy metals in the food chain. This paper reviews the phytotoxic effects and bioaccumulation of heavy metals in vegetables and food crops and assesses soil heavy metal thresholds for potential dietary toxicity. 相似文献
5.
CHEN Zu-yu 《浙江大学学报(A卷英文版)》2007,8(11):1712-1724
The solution of a slope stability problem can be approached by its least upper-bound and maximum lower-bound with high accuracy. The limit equilibrium methods that employ vertical slices imply a lower bound of the factor of safety. It has been successfully extended to the area of active earth pressure analysis that accounts for different input of locations of earth pressure applications. Those methods that employ slices with inclined interfaces give an upper-bound approach to the stability analysis. It enjoys a sound mechanical background and is able to provide accurate solutions of soil plasticity. It has been successfully extended to the area of bearing capacity analysis in which various empirical coefficients are no longer necessary. The 3D upper- and lower-bound methods under this framework have been made possible and show great potential for solving various engineering problems. 相似文献
6.
Yadolla Saeednia Mariani MD NOR 《美中教育评论》2010,7(5):94-100
Almost all schemes that have been issued by scholars or researchers to present Maslow＇s hierarchy of basic needs include a pyramid （triangle） in which the physiological needs are in the base and the self-actualization needs are in the top of the triangle. Although this scheming is inspiring to some results, basic needs have more characteristics that are significant however, this scheming is not able to inspire. Based on elaborating Maslow＇s theory and research＇s findings, this study aims to disclose weaknesses and strengths of traditional scheme （triangle）, and develop two innovated schemes of basic needs, which are more close to Maslow＇s ideas and more inspiring to realize the actuality of this hierarchy. 相似文献
7.
ASR technology for children with dyslexia： Enabling immediate intervention to support reading in Bahasa Melayu 总被引：1，自引：0，他引：1
Husniza Husni Zulikha Jamaludin 《美中教育评论》2009,6(6):64-70
Reading is an essential skill towards literacy development, and should be provided so that children can master the skill at their early ages. For dyslexic children, mastering the skill is a challenge. It has been widely agreed that the theory behind such difficulties in reading for dyslexic lies in the phonological-core deficits. Support has been given in many ways to dyslexic children to teach them reading through using various multi-sensory methods and using computer-based applications that include animated characters and text-to-speech （TTS） technology. In such applications, although stimulating, it requires the children to call for help by clicking on the custom-made buttons on the computer screen, often, such an application requires the dyslexic children to be aware of their mistakes and be able to judge when help is needed. They are just reluctant to ask the computer for help. Hence, such technology does not provide immediate intervention to correct any reading failure. It is therefore worth to look at the promising automatic speech recognition （ASR） technology to provide such intervention. Hence, this paper gives an overview of the use of ASR to facilitate immediate reading intervention which is the key element of remediating reading among dyslexic children. For such intervention to work, data on reading mistakes and patterns are observed and collected in audio format. The data serve as training and testing samples for an ASR to train on. An observation was carried out in two public schools participated in the study to record dyslexic children＇s reading in Bahasa Melayu （BM） and observe error patterns and their behaviors toward reading. A total of 10 dyslexic children are involved and a total of 6384 utterances from a set of selected words have been gathered and analyzed. Data are grouped into error type categories and the analysis performed gives ＂vowel substitution＂ as the most frequent error made （20%）. The significant findings can be of interest of special education teachers or parents to devise and use suitable approach to correct reading mistakes often made by dyslexic children. The findings also contribute to the development of a suitable and well-tuned ASR model focusing on dyslexic children reading aloud in BM. 相似文献
8.
Naveed Shibli 《美中教育评论》2009,6(5):61-66
Higher education is the product of three constituents, the policy makers or government, the executors or faculty and the recipients or the students or scholars. Steadiness among different constituents in given social interaction can act as facilitating motive and it could make higher education more smooth and productive. The “steadiness” in the pilot study is “a parameter that helps the three constituents of higher education to communicate to each other without ambiguity or say on a same frequency” and is very close to the factor “similarity”. Studies prove that “similarities” help group cohesion, improve performance and social relations etc. So to assume that the presence of like-mindedness or “similarity” or say “steadiness” in the field of higher education has the potential to decrease the amount of stress and to increase the productivity or outcome （successful policies, objective assessments, scholars, research, utility etc.）, is justified. And the assumption possesses the testable potential to study policy, assessment, implementation and other allied issues objectively. Many methods of social research and experimental designs are feasible for such study. A pilot study of a biography proves that the study of “similarity” in higher education for quality and assessment is viable and possesses the potential to produce better scholars, can enable the government to improve economy, can help to produce a strong next generation, can positively contribute to strengthen the social institutions and society and above all can bring a positive change in higher education that has been merely claimed for last many years. It is recommended that the proposed “similarity” may be studied in the field of higher education to help the government to formulate and execute policies based on social psychological evidence to enable the executors to best utilize their potential to help the recipients and learners to grow as per their full potential. 相似文献
9.
汤吉 《湖州师范学院学报》2003,25(Z1):149-153
Translation is a subject which needs to draw on findings and theories of other related subjects in order to develop andformalize its own methods. Stylistics is a borderline subject which has a great deal to offer to the translation studies. Since a lotof problems emerging in literary translation can be effectively solved by stylistic analysis, the present paper discusses tbe role ofstylistics in literary translation in deciding on methods of translation: literal translation or free translation and overcoming diffi-culties in translating poems. 相似文献
10.
During the decision-making process, especially in multi-disciplinary complex cases, assessment technique is needed to assist policy-makers in making the right decision. Many of such assessment techniques have been developed for policy-makers, but the inevitable subjectivity of policy-makers often becomes the main obstacle in making the right or proper policy. Interlink decision-making index （IDMI） is a newly proposed assessment method with the advantages of being simple to use and having less human interference over other methods, as it does not require a weighting process of each selection criterion. This paper implements IDMI to assist with decision-making in national or regional low-carbon development, using China as a case study. The Chinese government has annotmced its carbon emission reduction target along with other development targets by 2020. Many policy settings can be chosen in order to achieve those targets. The problem is how to determine the best setting and the means by which decision-makers can avoid subjectivity and extremes. A number of policy setting options are generated carefully by a system dynamic model under different policy scenarios. The IDMI demonstrates a perfect way to assist in selecting the ＂best＂ among all the options that can achieve the goals within the acceptable range. 相似文献
11.
Mwando Edward Angessa Tefera Tolera Han Yong Li Chengdao 《Journal of Zhejiang University. Science. B》2020,21(2):93-121
Salinity affects more than 6% of the world’s total land area, causing massive losses in crop yield. Salinity inhibits plant growth and development through osmotic and ionic stresses; however, some plants exhibit adaptations through osmotic regulation, exclusion, and translocation of accumulated Na+ or Cl-. Currently, there are no practical, economically viable methods for managing salinity, so the best practice is to grow crops with improved tolerance. Germination is the stage in a plant’s life cycle most adversely affected by salinity. Barley, the fourth most important cereal crop in the world, has outstanding salinity tolerance, relative to other cereal crops. Here, we review the genetics of salinity tolerance in barley during germination by summarizing reported quantitative trait loci (QTLs) and functional genes. The homologs of candidate genes for salinity tolerance in Arabidopsis, soybean, maize, wheat, and rice have been blasted and mapped on the barley reference genome. The genetic diversity of three reported functional gene families for salt tolerance during barley germination, namely dehydration-responsive element-binding (DREB) protein, somatic embryogenesis receptor-like kinase and aquaporin genes, is discussed. While all three gene families show great diversity in most plant species, the DREB gene family is more diverse in barley than in wheat and rice. Further to this review, a convenient method for screening for salinity tolerance at germination is needed, and the mechanisms of action of the genes involved in salt tolerance need to be identified, validated, and transferred to commercial cultivars for field production in saline soil.
相似文献12.
属间远缘杂交水稻耐铁毒性研究 总被引：4，自引：0，他引：4
以吉田昌—培养液为对照，添加不同浓度ＦｅＳＯ４作为铁毒胁迫处理，对二个属间远缘杂交水稻“远诱１号”和“遗传工程水稻１号”及三系杂交组合“汕优６３”二叶龄幼苗进行耐铁毒性比较鉴定．试验结果表明，３个试验材料的耐铁毒性以高粱稻远诱１号及三系稻汕优６３较强，遗传工程水稻１号耐铁毒性相对较弱．根据溶液中Ｆｅ２＋／Ｆｅ３＋的变化规律，稻体内持铁量的差异，稻株根系氧化力的区别，拒斥可能是汕优６３的耐铁毒性生理基础，遗传工程水稻１号的耐性机制为容耐，而远诱１号的耐铁生理基础兼具拒斥与氧化双重机制而偏倚于主动氧化机制．体内钾、硅、镁、钙含量与铁离子含量密切相关，丰富的钾、硅、镁可以改善水稻的耐铁毒性 相似文献
13.
The effect of Al and Cd on the growth, photosynthesis, and accumulation of Al, Cd and plant nutrients in two soybean genotypes were determined using hydroponic culture. There were six treatments: pH 6.5; pH 4.0; pH 6.5 1.0 μmol/L Cd; pH 4.0 1.0 μmol/L Cd; pH 4.0 150 μmol/L Al; pH 4.0 1.0 μmol/L Cd 150 μmol/L Al. The low pH (4.0) and Al treatments caused marked reduction in root length, shoot height, dry weight, chlorophyll content (SPAD value) and photosynthetic rate. Al-sensitive cv. Zhechun 2 accumulated comparatively more Al and Cd in plants than Al-tolerant cv. Liao 1. Compared with pH 6.5, pH 4.0 resulted in significant increase in Cd and Al concentration in plants. Combined application of Cd and Al enhanced their accu-mulation in roots, but caused a reduction in shoots. The concentrations of all 10 nutrients (P, K, Ca, Mg, Fe, Mn, Cu, Zn and B), except Mo were also increased when plants were exposed to pH lower than pH 6.5. Al addition caused a reduction in the con-centration of most nutrients in plant roots and shoots; but K, Mn and Zn in roots were increased. Treatments with Cd alone or together with Al reduced the concentrations of all the plant nutrients in plants. Al-sensitive genotype Zhechun 2 has lower nutrient concentration than Al-tolerant genotype Liao 1. The current findings imply that Al and Cd are synergistic in their effect on plant growth, physiological traits and nutrient uptake. 相似文献
14.
Aluminum (Al) toxicity is the major factor limiting crop productivity in acid soils. In this study, a recombinant inbreed line (RIL) population derived from a cross between an A1 sensitive lowland indica rice variety IR1552 and an Al tolerant upland japonica rice variety Azucena, was used for mapping quantitative trait loci (QTLs) for A1 tolerance. Three QTLs for relative root length (RRL) were detected on chromosome 1, 9, 12, respectively, and I QTL for root length under Al stress is identical on chromosome I after one week and two weeks stress. Comparison of QTLs on chromosome 1 from different studies indicated an identical interval between C86 and RZ801 with gene(s) for Al tolerance. This interval provides an important start point for isolating genes responsible for A1 tolerance and understanding the genetic nature of Al tolerance in rice. Four Al induced ESTs located in this interval were screened by reverse Northern analysis and confirmed by Northern analysis. They would be candidate genes for the QTL. 相似文献
15.
Warren Chanda Thomson P. Joseph Xue-fang Guo Wen-dong Wang Min Liu Miza S. Vuai Arshad A. Padhiar Min-tao Zhong 《Journal of Zhejiang University. Science. B》2018,19(4):253-262
Microorganisms provide both beneficial and harmful effects to human beings. Beneficial effects come from the symbiotic relationship that exists between humans and microbiota, but then several human illnesses have turned some friendly microbes into opportunistic pathogens, causing several microbial-related diseases. Various efforts have been made to create and utilize antimicrobial agents in the treatment and prevention of these infections, but such efforts have been hampered by the emergence of antimicrobial resistance. Despite extensive studies on drug discovery to alleviate this problem, issues with the toxicity and tolerance of certain compounds and continuous microbial evolution have forced researchers to focus on screening various phytochemical dietary compounds for antimicrobial activity. Linolenic acid and its derivatives (eicosapentaenoic acid and docosahexaenoic acid) are omega-3 fatty acids that have been studied due to their role in human health, being important for the brain, the eye, the cardiovascular system, and general human growth. However, their utilization as antimicrobial agents has not been widely appreciated, perhaps due to a lack of understanding of antimicrobial mechanisms, toxicity, and route of administration. Therefore, this review focuses on the efficacy, mechanism, and toxicity of omega-3 fatty acids as alternative therapeutic agents for treating and preventing diseases associated with pathogenic microorganisms. 相似文献
16.
Essa Ali Nazim Hussain Imran Haider Shamsi Zahra Jabeen Muzammil Hussain Siddiqui Li-xi Jiang 《Journal of Zhejiang University. Science. B》2018,19(2):130-146
The well-known detrimental effects of cadmium (Cd) on plants are chloroplast destruction, photosynthetic pigment inhibition, imbalance of essential plant nutrients, and membrane damage. Jasmonic acid (JA) is an alleviator against different stresses such as salinity and drought. However, the functional attributes of JA in plants such as the interactive effects of JA application and Cd on rapeseed in response to heavy metal stress remain unclear. JA at 50 μmol/L was observed in literature to have senescence effects in plants. In the present study, 25 μmol/L JA is observed to be a “stress ameliorating molecule” by improving the tolerance of rapeseed plants to Cd toxicity. JA reduces the Cd uptake in the leaves, thereby reducing membrane damage and malondialdehyde content and increasing the essential nutrient uptake. Furthermore, JA shields the chloroplast against the damaging effects of Cd, thereby increasing gas exchange and photosynthetic pigments. Moreover, JA modulates the antioxidant enzyme activity to strengthen the internal defense system. Our results demonstrate the function of JA in alleviating Cd toxicity and its underlying mechanism. Moreover, JA attenuates the damage of Cd to plants. This study enriches our knowledge regarding the use of and protection provided by JA in Cd stress. 相似文献
17.
T. Ramakrishna Rao 《Resonance》2018,23(5):545-553
In aquatic and moist soil environments subjected to periodic drying, a diverse group of organisms (mostly microscopic) have evolved extreme desiccation tolerance through a physiological adaptation called ‘anhydrobiosis’. Notable among such organisms are tardigrades, bdelloid rotifers, and nematodes. Anhydrobiosis also allows these organisms to tolerate extreme temperatures and ionizing radiation. In this article, the signi-cance and some mechanisms of anhydrobiosis are described. 相似文献
18.
酸性土壤中铝的活化及其对植物生长的影响 总被引：6，自引：0，他引：6
本文综述了酸雨对酸性土壤性质的影响及由此产生的对植物生长的影响。酸雨pH值越低 ,我国南方酸性土壤酸化越严重 ,土壤中盐基离子淋失量越大 ,铝的活化量也越大。土壤中盐基离子大量淋失 ,造成植物必要养分缺乏 ;铝的活化能够对植物产生毒害 ,影响植物的正常生长 ,甚至引起植物的死亡 相似文献
19.
Surface engineering has been emerging as one of the most promising technologies to improve the tribological properties of biomaterials with a view to extending the life span of medical implants. For example, some novel surface engineering techniques including ion implantation of ultra-high molecular weight polyethylene (UHMWPE) and thermal oxidation (TO) treatment of titanium alloy have been developed. However, the full potential of improving the wear resistance of orthopaedic implants based on the UHMWPE/ Ti6A14V system will not be realized until the tribological performance of this surface engineered tribo-system is fully characterized and the acting wear mechanisms are well understood. In this paper, a pin-on-disc tribometer was employed to evaluate the tribological response of the following three tribo-systems: (1) untreated UHMWPE/untreated Ti6A14V. (2) untreated UHMWPE/TO-treated Ti6A14V and (3) ion implanted UHMWPE/TO treated Ti6A14V under water lubricated conditions. Experimental results show that the tribological properties of UHMWPE can be significantly increased by surface enghmering its surface and/or the counterface. Tiffs can be attributed to the hardened surface of UHMWPE via molecular structure modification induced by ion bean bombardment coupled with the surface oxide layer on Ti6A14V formed during TO treatment, which has favorable tribological compatibility with UHMWPE. 相似文献