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1.
Mycorrhizoremediation an enhanced form of phytoremediation   总被引:2,自引:0,他引:2  
Study of plant roots and the diversity of soil micro biota, such as bacteria, fungi and microfauna associated with them, is important for understanding the ecological complexities between diverse plants, microbes, soil and climates and their role in phytoremediation of contaminated soils. The arbuscular mycorrhizal fungi (AMF) are universal and ubiquitous rhizosphere mi- croflora forming symbiosis with plant roots and acting as biofertilizers, bioprotactants, and biodegraders. In addition to AMF, soils also contain various antagonistic and beneficial bacteria such as root pathogens, plant growth promoting rhizobacteria including free-living and symbiotic N-fixers, and mycorrhiza helping bacteria. Their potential role in phytoremediation of heavy metal (HM) contaminated soils and water is becoming evident although there is need to completely understand the ecological complexities of the plant-microbe-soil interactions and their better exploitation as consortia in remediation strategies employed for contaminated soils. These multitrophic root microbial associations deserve multi-disciplinary investigations using molecular, biochemical, and physiological techniques. Ecosystem restoration of heavy metal contaminated soils practices need to incorporate microbial biotechnology research and development. This review highlights the ecological complexity and diversity of plant-microbe-soil combinations, particularly AM and provides an overview on the recent developments in this area. It also discusses the role AMF play in phytorestoration of HM contaminated soils, i.e. mycorrhizoremediation.  相似文献   

2.
Handwriting: Evolution and evaluation   总被引:1,自引:1,他引:0  
Handwriting, “everyone’s art,” is an indispensable skill. The roots of our present forms of penmanship are traced. When and which initial style to teach children, especially the dyslexic or learning disabled, are discussed. The need for a good instrument to evaluate handwriting to prevent perpetuation of illegibilities or to determine if speed is rapid enough to meet the writer’s purpose is paramount. A new diagnostic tool, the Children’s Handwriting Evaluation Scale (CHES) and its college counterpart are detailed. The CHES also provides a projective scoring key based on graphoanalytic interpretations.  相似文献   

3.
Happy Me a Story     
Current research on the foundations of emotional well-being reveals how significant adults can establish roots of happiness in children. Carter (2005) suggests that these roots can be nourished through positive thoughts and emotions; flow and fulfillment; and relating to others, especially through the use of emotional intelligence. Twenty-five literature choices are reviewed and recommended to help adults nurture children’s happiness in these ways.  相似文献   

4.
1IntroductionTheHopfbifurcationisanimportantaspectofdynamicalsystems.SoseekingHopfbifuractionpointsisgetingveryimportant.[3],...  相似文献   

5.
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   

6.
In order to advance the purpose of education as creating a sustainable world yet to be imagined, educationally, queer (v.) queer (v.) expounds curriculum, pedagogy and being, which has roots in sexuality—the public face of the private confluence of sexuality, gender, race and class, are a necessary framework for queer. If queer is a complicated conversation of strangers’ eros, then queer facilitates the creation of space, revolution and transformation. In other words, queer, for science education, is more than increasing and privileging the heteronormative and non-heteronormative science content that extends capitalism’s hegemony, but rather science as the dignity, identity, and loving and caring of and by one’s self and fellow human beings as strangers.  相似文献   

7.
This paper presents a curriculum, textbook and test result analysis for the new (to California) elementary school “Key Standard” mathematics curriculum, transplanted in 1998 from it's foreign roots in Asia and Europe, locations with far different cultural and economic backgrounds. Based on topic analysis methods developed by Michigan State University, this curriculum is a “quality” curriculum, since it is closely aligned with the curriculum of the six leading TIMSS math countries. Five-year test results are presented for two cohorts totaling over 13,000 students, all from four “early adoption” urban districts where 68% of the students were economically disadvantaged. Included are two cohorts of English learning immigrants totaling over 4,400 students. Performance was found to be statistically superior to similar (control) districts which continued with the old 1991 curriculum and textbooks (0.003 < p < 0.015). The focus of this paper is on the transition from far-below to above average learning performance of these students over the 1998–2002 period.  相似文献   

8.
Representative pioneer tree root systems in the subtropical area of South China were examined with regard to their structure, underground stratification and biomass distribution. Excavation of skeleton roots and observation of fine roots of seven species including the Euphorbiaceae, Theaceae, Melastomataceae, Lauraceae and Fagaceae families was carried out. The results showed that: (1) Pioneer tree roots in the first stage of natural succession were of two types, one characterized by taproot system with bulky plagiotropic branches; the other characterized by flat root system with several tabular roots. The late mesophilous tree roots were characterized by one obvious taproot and tactic braches roots up and down. Shrub species roots were characterized by heart fibrous root type featured both by horizontally and transversally growing branches. Root shapes varied in different dominant species at different stages of succession. (2) Roots of the different species varied in the external features-color, periderm and structure of freshly cut slash. (3) In a set of successional stages the biomass of tree roots increased linearly with the age of growth. During monsoon, the total root biomass amounted to 115.70 t/ha in the evergreen broadqeaved forest; 50.61 t/ha in needle and broad-leaved mixed forest dominated by coniferous forest; and 64.20 t/ha in broad-and needle-leaved mixed forest dominated by broad-leaved heliophytes, and are comparable to the underground biomass observed in similar tropical forests. This is the first report about roots characteristics of forest in the lower sub-tropical area of Dinghushan, Guangdong, China.  相似文献   

9.
This study explores how elementary teachers perceive and use engaging oral strategies (i.e., manners of speaking that encourage students to participate and become engaged in science discussions). It is reported that the strategies employed as well as their frequency varied substantially depending upon on the teachers’ grade level and perceptions. While a kindergarten teacher viewed such strategies negatively and employed only a few figurative directives, fourth-grade teachers viewed them positively, frequently resorting to a variety of speech figures, parallel repetition and engaging questions. It is argued that teachers’ engaging oral strategies are multifunctional, serving important social and cognitive functions.  相似文献   

10.
Lead concentrations in roots, stems and leaves of accumulating and non-accumulating ecotypes ofSedum alfredii (Hance) were studied through a hydroponic experiment with different Pb concentrations supplied as Pb(NO3)2. Lead concentrations in leaves and stems of the accumulating ecotype were 4–9 times and 3–5 times those of the non-accumulating ecotype, and Pb-accumulated amounts in stems and leaves of the accumulating ecotype were 4–9 times and 8–11 times higher than those of the non-accumulating ecotype, respectively. The results indicated that the accumulating ecotype had better ability to transport Pb from roots to shoots. The subcellular distributions of Pb in the root, stem and leaf tissues were studied using sucrose differential centrifugation. Approximately 50% of Pb contents was found to be associated with the cell wall fraction in stems of the accumulating ecotype and the percentage increased to 80% both in roots and leaves, no matter when plants were grown with different levels of Pb. The results indicated that the distribution of Pb on cell walls of the accumulating ecotype could mainly account for the high tolerance to Pb. Project supported by a Key Project from the Educational Ministry of China (No:02180) and by the Outstanding Young Scientist Grant from the National Natural Science Foundation of China (No: 39925024).  相似文献   

11.
This paper proposes co-opting high school students’ paid part-time work experiences to develop their critical understanding of the world of work, beyond their schooling through post-school pathways. It argues that unlike work experience program or work placements organised through schools, students’ paid part-time employment provides authentic workplace experiences that have the potential to inform students deeply and critically about the world of work. These experiences include the reciprocal obligations that arise from paid employment and, as such, provide a rich base for high school students to explore the world of work, relationships in the workplace, what constitutes more and less valued work and how work is organised and rewarded. The co-opting of students’ work experiences for school-based activities may provide a useful base to explore the world of work both for those students who are employed part-time and those not employed in part-time work, but able to learn from their peers’ experiences. To assist achieving these goals some pedagogic tools are required to effectively describe, analyse and illuminate these experiences in classroom settings. A way of describing and critically appraising this paid work is proposed through individual and collective consideration of the activities and interactions that constitute students’ paid work experience. Given the difficulty of organising workplace placements and work experience programs, and the potentially richer outcomes, co-opting students’ paid work experiences presents a viable and worthwhile resource available in most classrooms for learning more about the world of work.  相似文献   

12.
In higher education dual systems, graduates are qualified to apply for jobs in same professional fields along two separated educational routes. The research problem is whether the rival applicants for professional positions are treated equally in the labour market despite their different qualifications. From the graduates point of view, to be equal means to have an opportunity to be employed in accordance with one’s professional skill. Applying European survey data, the article tests to what extent the ‘distribution of work’ between university and non-university graduates seems to be based on educational qualifications or actual competence. Among 4,000 German, Dutch, Finnish, and Swiss graduates primarily in business and administration and engineering, only slight and occasional evidence of ‘status-based recruitment’ was found. All in all, the research suggests that from the view of graduate employment, the European dual HE systems work very much following the principle of ‘different but equal’.  相似文献   

13.
The study reported here examined grade 2–4 children’s sensitivity to the consistency in the spelling of roots in related words. We build on earlier research by attempting to quantify the extent that children’s spellings of both inflected and derived forms accord with this principle. We contrasted children’s accuracy and consistency in spelling the root form (e.g., rock) with that of its spelling in related inflected and derived forms (e.g., rocks and rocky), as well as unrelated control forms (e.g., rocket). Across grades 2–4, children’s spellings accorded with the root consistency principle to the same extent for inflected and derived forms. Nevertheless, it was not until grade 4 that spellings maximally reflected the principle. These results are discussed in terms of how children’s spelling might come to reflect the root consistency principle that guides spelling in English.  相似文献   

14.
Conclusion The goal here has been to offer just one possible path that HP technologists might take to meet the theoretical and practical challenges presented by knowledge management precepts and practices. Thinking about knowledge as a process and contemplating interventions at collective and organizational levels are not easy tasks, especially given our conventional roots. Fortunately, there are emerging perspectives that may greatly facilitate the HP technologist’s venture into this arena. My suggestion is that we begin to use these and related theories to inform and improve development.  相似文献   

15.
This paper reports on a study conducted among Greek kindergarten teachers aiming to explore their conceptual frameworks on a major environmental issue of our times: the ozone layer depletion. The choice of this particular issue was premised on its novelty, complexity and abstractness which present teachers with difficulties in its teaching. A free word association task was employed to identify the associative meaning of the issue among the participant teachers. The study’s results revealed the existence of a simplistic, linear, cause-and-effect scheme in the teachers’ conceptual frameworks, the two poles of which are “solar radiation” and “its harmful results for human health”. Some of the well-known misconceptions and misunderstandings already emerged in previous research also arise in this study. Prominent among them are the deeply rooted confusion between the “ozone hole” and “greenhouse effect”, a general fusion of ideas concerning all environmental problems and an overemphasis on the harmful consequences of the ozone depletion on human health. Implications for kindergarten teacher education are also discussed.The present study is part of a research project that is co-funded by the European Social Fund and National Resources – (EPEAEK II) PYTHAGORAS II.  相似文献   

16.
INTRODUCTION Dementia is becoming a big problem in modern life, and particularly, it takes place more frequently in mental job group and the elderly. Today, more than 20 million people in the world catch this disease (Francis et al., 1999; Almkvist et al., 1998). So how to detect underlying dementia and take preventive measure is critical for both the doctors and their patients. People with dementia always behave slowly and their memory decreases with the development of the disease. Curr…  相似文献   

17.
Comprehension of science topics occurs when learners meaningfully generate relationships and conceptions about what they read. In this generation process, learners’ cognitive and metacognitive regulation is one of the most critical factors influencing learning. However, learners are not always successful in regulating their own learning, especially in computer-based learning environments (CBLEs) where they are alone. Based on this rationale, the present study was designed to examine the effects of two scaffolding strategies—generative learning strategy prompts and metacognitive feedback—on learners’ comprehension and self-regulation while learning the human heart system in a CBLE. Participants were 223 undergraduate student volunteers. Structural Equation Modeling (SEM) was employed to conceptualize and empirically test a model that explains mediating processes among variables. Results revealed that the combination of generative learning strategy prompts with metacognitive feedback improved learners’ recall and comprehension by enhancing learners’ self-regulation and better use of highlighting and summarizing as generative learning strategies.  相似文献   

18.
The integration of history into educational practice can lead to the development of activities through the use of genetic ‘moments’ in the history of mathematics. In the present paper, we utilize Oresme’s genetic ideas – developed during the fourteenth century, including ideas on the velocity–time graphical representation as well as geometric transformations and reconfigurations – to develop mathematical models that can be employed for the solution of problems relating to linear motion. The representation of distance covered as the area of the figure between the graph of velocity and the time axis employed in these activities, leads on naturally to the study of problems on motion by means of functions, as well as allowing for the use of tools (concepts and propositions) from Euclidean geometry of relevance to such problems. By employing simple geometric transformations, equivalent real life problems are obtained which lead, in turn, to a simple classification of all linear motion-related problems. When applied to a wider range of motion problems, this approach prepares the way for the introduction of basic Calculus concepts (such as integral, derivative and their interrelation); in fact, we would argue that it could be beneficial to teach the basic concepts and results of Calculus from an early grade by employing natural extensions of the teaching methods considered in this paper.  相似文献   

19.
Few studies deal with teachers’ receptivity in the initiation stage of educational change, especially in a non-western cultural context like Mainland China. This study aims at investigating teachers’ receptivity to the system-wide curriculum reform of the senior secondary education in the initiation stage and understanding the factors influencing teachers’ receptivity in Mainland China. Questionnaire survey with open-ended question (n = 763) is employed to explore teachers’ receptivity in four selected experimental provinces, i.e., the first group of provinces which are selected by Ministry of Education to implement the curriculum reform. Results indicate teachers have positive attitudes and behavioral intentions toward promoting the curriculum reform of senior secondary education, and they consider the reform is valuable but difficult to carry out. The existing theoretical model can explain teachers’ behavioral intentions quite well, but its predicting ability to teachers’ general attitudes is limited, which indicates some new variables that need to be considered, too. Implications of this study and suggestions for future research are also discussed in the article.  相似文献   

20.
Organized research units—also known as centers, institutes, and laboratories—are increasingly prominent in the university. This paper examines how ORUs emerge to promote global agendas and international collaborations in an academic health center in North America. The roles these units play in helping researchers work across institutional and national boundaries are identified and analyzed. The concept of boundary organizations is employed to explain the features of ORUs and the challenges they face. Findings provide insight into how such units operate between local and global mandates, interest groups, and sources of influence, helping to extend university research into the global space.  相似文献   

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