Morphological and biochemical responses of Oryza sativa L. (cultivar MR219) to ion beam irradiation   总被引：1，自引：0，他引：1  

Anna Pick Kiong Ling  Ying Chian Ung  Sobri Hussein  Abdul Rahim Harun  Atsushi Tanaka  Hase Yoshihiro 《Journal of Zhejiang University. Science. B》2013,14(12):1132-1143

Objective

Heavy ion beam, which has emerged as a new mutagen in the mutation breeding of crops and ornamental plants, is expected to result in the induction of novel mutations. This study investigates the morphological and biochemical responses of Oryza sativa toward different doses of carbon ion beam irradiation.

Methods

In this study, the dry seeds of O. sativa were irradiated at 0, 20, 40, 60, 80, 100, and 120 Gy, followed by in-vitro germination under controlled conditions. Morphological and biochemical studies were conducted to investigate the morphological and physiological responses of O. sativa towards ion beam irradiation.

Results

The study demonstrated that low doses (10 Gy) of ion beam have a stimulating effect on the height, root length, and fresh weight of the plantlets but not on the number of leaves. Meanwhile, doses higher than 10 Gy caused reductions in all the morphological parameters studied as compared to the control samples. The highest total soluble protein content [(2.11±0.47) mg/g FW] was observed in plantlets irradiated at 20 Gy. All irradiated plantlets were found to have 0.85% to 58.32% higher specific activity of peroxidase as compared to the control samples. The present study also revealed that low doses of ion beam (10 and 20 Gy) had negligible effect on the total chlorophyll content of O. sativa plantlets while 40 Gy had a stimulating effect on the chlorophyll content. Plantlets irradiated between 40 to 120 Gy were shown to be 0.38% to 9.98% higher in total soluble nitrogen content which, however, was not significantly different from the control samples.

Conclusions

Carbon ion beam irradiation administered at low to moderate doses of 10 to 40 Gy may induce O. sativa mutants with superior characteristics.  相似文献   

Training Planning and Working Memory in Third Graders     

Andrea Paula Goldin  María Soledad Segretin  María Julia Hermida  Luciano Paz  Sebastián Javier Lipina  Mariano Sigman 《Mind, Brain, and Education》2013,7(2):136-146

Working memory and planning are fundamental cognitive skills supporting fluid reasoning. We show that 2 games that train working memory and planning skills in school‐aged children promote transfer to 2 different tasks: an attentional test and a fluid reasoning test. We also show long‐term improvement of planning and memory capacities in 8‐year‐old children after playing adaptive computer games specifically tailored to entrain these cognitive functions. Working memory capacity expanded from 5 to 7 items by using our games. Furthermore, steady progression in the task indicates that this capacity can be trained rapidly. Planning abilities persisted in a nonmarkovian form of play, where a move is highly influenced by previous moves, avoiding back‐ups. Here, we introduce a public and growing platform ( http://www.matemarote.com.ar/ ) developed for this research which has the potential for wide use in educational research.  相似文献   

The Influence of Reading Expertise in Mirror‐Letter Perception: Evidence From Beginning and Expert Readers     

Jon Andoni Duñabeitia  María Dimitropoulou  Adelina Estévez  Manuel Carreiras 《Mind, Brain, and Education》2013,7(2):124-135

The visual word recognition system recruits neuronal systems originally developed for object perception which are characterized by orientation insensitivity to mirror reversals. It has been proposed that during reading acquisition beginning readers have to “unlearn” this natural tolerance to mirror reversals in order to efficiently discriminate letters and words. Therefore, it is supposed that this unlearning process takes place in a gradual way and that reading expertise modulates mirror‐letter discrimination. However, to date no supporting evidence for this has been obtained. We present data from an eye‐movement study that investigated the degree of sensitivity to mirror‐letters in a group of beginning readers and a group of expert readers. Participants had to decide which of the two strings presented on a screen corresponded to an auditorily presented word. Visual displays always included the correct target word and one distractor word. Results showed that those distractors that were the same as the target word except for the mirror lateralization of two internal letters attracted participants' attention more than distractors created by replacement of 2 internal letters. Interestingly, the time course of the effects was found to be different for the 2 groups, with beginning readers showing a greater tolerance (decreased sensitivity) to mirror‐letters than expert readers. Implications of these findings are discussed within the framework of preceding evidence showing how reading expertise modulates letter identification.  相似文献   

Outcomes of a scientific nonformal educational initiative for youth in Rio de Janeiro     

Isabela Cabral Félix de Sousa 《Cultural Studies of Science Education》2013,8(1):193-213

The aim of this research is to understand how former students view their professional and academic paths after taking part in a specific scientific nonformal educational initiative during high school. This program is called Vocational Scientific Program (Provoc) and is carried out in the Oswald Cruz Foundation (Fiocruz), Rio de Janeiro, Brazil. This institution has for over 100 years played a pioneer role in public health research in the country. This institution has many graduate programs and a high school dedicated to training students in health issues. Provoc was originated in this school and has been part of it for the last 25 years. Since its beginning, this program has been characterized by a significant predominance of women which relates to the female predominance of professionals in this institution working in the traditional areas of Fiocruz, which are Biology, Medicine, Public Health, Humanities and Social Sciences. This study was qualitative in nature and involved observations and 34 individual interviews, which followed a semi structured questionnaire, designed for this research. The results indicate that the majority of participants see their program participation experiences as an asset in their academic and professional careers. Many describe feeling empowered by presenting their work in seminars and a few by writing a research article. Many former students also testified to the establishment of social long lasting relationships in the research work environment. And finally, the interviews reveal a few moments and the factors involved in the selection of a profession by youth.  相似文献   

Doing dissections differently: A structured,peer‐assisted learning approach to maximizing learning in dissections     

Emma R. Hall  Rachel C. Davis  Renate Weller  Sonya Powney  Sarah B. Williams 《Anatomical sciences education》2013,6(1):56-66

Areas of difficulty faced by our veterinary medicine students, with respect to their learning in dissection classes, were identified. These challenges were both general adult‐learning related and specific to the discipline of anatomy. Our aim was to design, implement, and evaluate a modified reciprocal peer‐assisted/team‐based learning format—Doing Dissections Differently (DDD)—to complement existing dissection classes, with the intention of enhancing both student learning and the student learning experience. Second year veterinary medicine students (n = 193), in their usual dissection groups, were randomly assigned to one of four roles: anatomist, clinician, radiologist, and learning resources manager. Students attended a preparatory workshop outlining the skills required for effective execution of their role. They were then asked to perform their roles throughout five consecutive musculoskeletal dissection classes. Student attitudes to dissection classes before and after DDD were evaluated by questionnaire (146 respondents). There was a significant (P = 0.0001) improvement after DDD in a number of areas: increased perceived value of dissection classes as an anatomy learning aid; improved appreciation of the clinical relevance of anatomy; increased use of resources before and during dissection classes; and longer preparation time for dissection classes. Before DDD, 45% of students felt that at least one peer did not contribute usefully to the group during dissection classes; no improvement was seen in this measure after DDD. Although the new format highlighted a potential need to improve teamwork, most students actively engaged with DDD, with dissection classes valued more highly and utilized more effectively. © 2012 American Association of Anatomists.  相似文献   

Talking about death: Implementing peer discussion as a coping mechanism to overcome fears about dissection,death, and dying     

Sanet Henriët Kotzé  Calvin Gerald Mole 《Anatomical sciences education》2013,6(3):191-198

Many studies have reported on the perceptions of medical students toward dissection. It is important to understand the feelings and symptoms experienced during dissection so that they can be adequately handled. Prior to dissection, first year students are given lectures on aspects of dissection, death and dying, and death rituals in various cultures. Two separate questionnaires, one given during the first week of dissection and another given one month into the program were then completed anonymously by dissection groups. The questions were designed to be open‐ended, thereby encouraging group discussion amongst students. The questionnaires were used to determine the perception of students to dissection and to discover if these perceptions change during the dissection program. The first questionnaire revealed that students do experience fears and anxiety prior to and at the beginning of dissection; however, most of these fears dissipated by the time of the second questionnaire. One month into dissection students cited talking to peers as their main coping mechanism and fewer students mentioned emotional detachment from their cadaver as a coping mechanism, as was the case in the first questionnaire. Dissection was perceived as a positive experience by our student cohort and most students cited the main advantage of dissection as the ability to visualize organs in three dimensions. The comprehensive answers received from the students indicated that thorough discussion of feelings amongst peers occurred, introducing students to an important coping mechanism at an early stage of their learning. Anat Sci Educ. © 2013 American Association of Anatomists.  相似文献   

Guiding Principles for In-Service Improvement     

Daniel R. Hall 《College Teaching》2013,61(2)

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The View from Above     

Derek Potgieter  Sandra Olën 《International Information and Library Review》2013,45(4):259-271

Abstract

In South Africa the education system for black children is fraught with problems. These problems are the direct result of apartheid and have been compounded by poverty and illiteracy. In this article the problem of poorly qualified or unqualified teachers is discussed especially with regard to the teaching of map skills to children in their fifth school year. The project team needed to develop affordable materials which could be used in large classes by teachers after a very short period of training. Books and other materials which are available commercially were examined, but for various reasons were found to be unsuitable for local conditions. After determining the extent of the problem, the project team followed a grassroots process of developing a flip chart which teachers learnt to use with confidence and which enabled pupils to master the concepts and skills necessary for understanding a map.  相似文献   

Convergence of Visions     

Thérèse Paquet-Sévigny 《International Information and Library Review》2013,45(3-4):447-454

The right for everyone to access “the promised land” of the InfoSociety is widely recognized. The “wiring of the universe” is now technically and financially possible. One should do it quickly in the respect of human values and rights, freedom of opinion, transparency and cultural diversity. However, in the context of communication developments in 1997, it is a multifacet issue of concern to all the countries. The cyberspace era brings many new challenges to the communications' academic curricula, professional practices, media owners and the research and development (R&D) of industries across the world. The emerging virtual communities change social and political relationships, as well as the job market well beyond national and linguistic boundaries. The paper examines the minimal conditions needed for this open process to take place with the participation of all players and the possible role of ORBICOM, the network of UNESCO Chairs in Communication.  相似文献   

Commercial ethnicity: Language,class and race in the marketing of the hispanic audience     

América Rodriguez 《The Communication Review》2013,16(3):283-309

This essay examines the historical construction of the Hispanic audience and analyzes how contemporary Hispanic audience researchers/marketers have disrupted that unitary, essentialist construction by segmenting the Hispanic audience by class. The principal tool in this effort is language: the Spanish language is proxy for the “mass” of lower socioeconomic class Hispanic audience; English language usage by Hispanics is the sign of a higher class of Hispanic audience. The clearly defined panethnic conceptualization of the Hispanic audience, the nexus of which is the Spanish language, has been blurred. The study draws on interviews with Hispanic media marketers and audience researchers and on analysis of Hispanic market research reports.  相似文献