WorldWideScience

Sample records for socioscientific issues inherently

  1. The Morality of Socioscientific Issues: Construal and Resolution of Genetic Engineering Dilemmas

    Science.gov (United States)

    Sadler, Troy D.; Zeidler, Dana L.

    2004-01-01

    The ability to negotiate and resolve socioscientific issues has been posited as integral components of scientific literacy. Although philosophers and science educators have argued that socioscientific issues inherently involve moral and ethical considerations, the ultimate arbiters of morality are individual decision-makers. This study explored…

  2. Promoting Preservice Teachers' Attitudes toward Socioscientific Issues

    Science.gov (United States)

    Yerdelen, Sundus; Cansiz, Mustafa; Cansiz, Nurcan; Akcay, Hakan

    2018-01-01

    In this study, we aimed to improve preservice teachers' attitudes toward socioscientific issues through socioscientific issue course. Moreover, we investigated whether this course influences preservice teachers studying in a science education and non-science education in a similar way. For this purpose, a semester-long socioscientific issues…

  3. Socioscientific Issues and the Affective Domain: Scientific Literacy's Missing Link.

    Science.gov (United States)

    Sadler, Troy D.

    The promotion of scientific literacy has become an important goal for science education, and the ability to negotiate socioscientific issues is at least one aspect of scientific literacy. This paper focuses on how the moral dimensions of socioscientific issues influence decision-making regarding these issues. Morality is examined from multiple…

  4. Contribution of socio-scientific issues to development of critical

    Directory of Open Access Journals (Sweden)

    Solbes, Jordi

    2013-01-01

    Full Text Available In this paper we try to justify that socio-scientific issues can help to develop critical thinking of students, based on the science education and history of science. These considerations of the history of science can be transformed into socio-scientific issues (SSI, which can be used in science classes.

  5. The role of socioscientific issues in biology teaching – from the perspective of teachers

    OpenAIRE

    Tidemand, Sofie; Nielsen, Jan Alexis

    2017-01-01

    Previous research has documented that students who engage with socioscientific issues can acquire some of the complex competences and skills typically related to scientific literacy. But an emerging field of research on science teachers’ understanding and use of socioscientific issues, has documented that a range of challenges hinders the uptake of socioscientific issues. In this study we investigated the interpretation and implementation of socioscientific issues among Danish biology teacher...

  6. The role of socioscientific issues in biology teaching – from the perspective of teachers

    DEFF Research Database (Denmark)

    Tidemand, Sofie; Nielsen, Jan Alexis

    2017-01-01

    Previous research has documented that students who engage with socioscientific issues can acquire some of the complex competences and skills typically related to scientific literacy. But an emerging field of research on science teachers’ understanding and use of socioscientific issues, has...... documented that a range of challenges hinders the uptake of socioscientific issues. In this study we investigated the interpretation and implementation of socioscientific issues among Danish biology teachers – who teach in a curriculum that, on paper, is permeated by socioscientific issues. We conducted five...... harbour a content-centred interpretation of socioscientific issues which manifests itself in at least three separate ways. First, the teachers generally use socioscientific issues as a means to an end of teaching factual biological content. Second, the teachers had a clear emphasis on mastery of factual...

  7. The morality of socioscientific issues: Construal and resolution of genetic engineering dilemmas

    Science.gov (United States)

    Sadler, Troy D.; Zeidler, Dana L.

    2004-01-01

    The ability to negotiate and resolve socioscientific issues has been posited as integral components of scientific literacy. Although philosophers and science educators have argued that socioscientific issues inherently involve moral and ethical considerations, the ultimate arbiters of morality are individual decision-makers. This study explored the extent to which college students construe genetic engineering issues as moral problems. Twenty college students participated in interviews designed to elicit their ideas, reactions, and feelings regarding a series of gene therapy and cloning scenarios. Qualitative analyses revealed that moral considerations were significant influences on decision-making, indicating a tendency for students to construe genetic engineering issues as moral problems. Students engaged in moral reasoning based on utilitarian analyses of consequences as well as the application of principles. Issue construal was also influenced by affective features such as emotion and intuition. In addition to moral considerations, a series of other factors emerged as important dimensions of socioscientific decision-making. These factors included personal experiences, family biases, background knowledge, and the impact of popular culture. The implications for classroom science instruction and future research are discussed.

  8. Science Teachers Taking their First Steps toward Teaching Socioscientific Issues through Collaborative Action Research

    Science.gov (United States)

    Lee, Hyunju; Yang, Jung-eun

    2017-06-01

    This study presents two science teachers, Catherine and Jennifer, who took their first steps toward teaching socioscientific issues through collaborative action research. The teachers participated in the collaborative action research project because they wanted to address socioscientific issues but had limited experience in teaching them. The research questions included what kinds of challenges the teachers encountered when implementing socioscientific issues and to what extent they resolved the challenging issues as participating in collaborative action research. The primary data source consisted of audiotapes of regular group meetings containing information on the process of constructing and implementing lesson plans and reflecting on their teaching of socioscientific issues. We also collected classroom videotapes of the teachers' instruction and audiotapes of students' small group discussions and their worksheets. The findings indicated that when addressing socioscientific issues in the classes, the teachers encountered several challenging issues. We categorized them into four: (1) restructuring classroom dynamics and culture, (2) scaffolding students' engagement in socioscientific issues, (3) dealing with values, and (4) finding their niche in schools. However, this study showed that collaborative action research could be a framework for helping the teachers to overcome such challenges and have successful experiences of teaching socioscientific issues. These experiences became good motivation, to gradually develop their understanding of teaching socioscientific issues and instructional strategies for integrating the knowledge and skills that they had accumulated over the years.

  9. Lack of Evolution Acceptance Inhibits Students' Negotiation of Biology-Based Socioscientific Issues

    Science.gov (United States)

    Fowler, S. R.; Zeidler, D. L.

    2016-01-01

    The purpose of this study was to explore science content used during college students' negotiation of biology-based socioscientific issues (SSI) and examine how it related to students' conceptual understanding and acceptance of biological evolution. The Socioscientific Issues Questionnaire (SSI-Q) was developed to measure depth of evolutionary…

  10. The Role of Socioscientific Issues in Biology Teaching: From the Perspective of Teachers

    Science.gov (United States)

    Tidemand, Sofie; Nielsen, Jan Alexis

    2017-01-01

    Previous research has documented that students who engage with socioscientific issues can acquire some of the complex competences and skills typically related to scientific literacy. But an emerging field of research on science teachers' understanding and use of socioscientific issues, has documented that a range of challenges hinders the uptake…

  11. Positive Emotional Responses to Hybridised Writing about a Socio-Scientific Issue

    Science.gov (United States)

    Tomas, Louisa; Ritchie, Stephen M.

    2012-01-01

    In order to understand better the role of affect in learning about socio-scientific issues (SSI), this study investigated Year 12 students' emotional arousal as they participated in an online writing-to-learn science project about the socio-scientific issue of biosecurity. Students wrote a series of hybridised scientific narratives, or BioStories,…

  12. Lakatos' Scientific Research Programmes as a Framework for Analysing Informal Argumentation about Socio-Scientific Issues

    Science.gov (United States)

    Chang, Shu-Nu; Chiu, Mei-Hung

    2008-01-01

    The purpose of this study is to explore how Lakatos' scientific research programmes might serve as a theoretical framework for representing and evaluating informal argumentation about socio-scientific issues. Seventy undergraduate science and non-science majors were asked to make written arguments about four socio-scientific issues. Our analysis…

  13. Teacher formation related to socio-scientific issues: complexity, contributions and limitations of an educational practice

    Directory of Open Access Journals (Sweden)

    Mariuce Campos de Moraes

    2015-12-01

    Full Text Available This reflection refers to teacher formation related to socio-scientific issues. Whereas such matters take into account the impact of scientific development in society, including ethical aspects and encompass dilemmas involving a wide range of prospects for its resolution, we propose analysis of the complexity that is inherent in their teaching. Thus, we aimed to analyze different spaces and teaching time that produce and are produced in close linkage between theory and practice, as well as their contributions and limitations. The study required a dynamic conversation system that led to the analysis indicators. The issue of sustainability was shown to be feasible for educational planning as cover technical and scientific knowledge, ethical, social and economic pressures. The collective production allowed understand arguments and reflective-creative processes. The lived relations in schools has accompanied and limited the ideas expressed on the socio-scientific issues. We understand that the simultaneity of research and reflection in the sociocultural context has strengthened teacher formation.

  14. Development of Socioscientific Issues-Based Teaching for Preservice Science Teachers

    OpenAIRE

    Prasart Nuangchalerm

    2009-01-01

    Problem statement: In the context of science education reform in Thailand, we need to prepare science teachers who can face science and social issues controversial; teachers can response the question socioscientific issues and let their students to meet the goal of science education. This study investigated the conception leading preservice science teachers approaching socioscientific issues-based teaching. The activities in classroom emphasized on peer discussion about science and social ref...

  15. Socioscientific issues: topics and importance to the scientific education

    Directory of Open Access Journals (Sweden)

    Díaz Moreno, Naira;

    2012-01-01

    Full Text Available Socioscientific debates arise and become widespread concerning the most popular and innovative issues in our society: transgenics, homeopathy, the impact of mobile phone network and so on. For this reason we believe it is important to analyse the meaning of these debates and the relationship between information processing in newspapers and teaching literature and to determine their possible use in a school context. The common image of scientific news that tends to appear in the media hampers its use in the classroom. On analysing didactic literature, we have selected activities that can be used as a model to plan debates in the science classroom with the objective of developing a series of capacities in students related to scientific literacy, critical thinking and the promotion of a scientific culture.

  16. Prospective Elementary School Teachers’ Views about Socioscientific Issues: A Concurrent Parallel Design Study

    OpenAIRE

    Muhammet ÖZDEN

    2015-01-01

    The purpose of this research is to examine the prospective elementary school teachers’ perceptions on socioscientific issues. The research was conducted on prospective elementary school teachers studying at a university located in western Turkey. The researcher first taught the subjects of global warming and nuclear power plants from a perspective of socioscientific issues in the science and technology education course and then conducted the research. Concurrent parallel design, one of the mi...

  17. Learning outcomes between Socioscientific Issues-Based Learning and Conventional Learning Activities

    OpenAIRE

    Piyaluk Wongsri; Prasart Nuangchalerm

    2010-01-01

    Problem statement: Socioscientific issues-based learning activity is essential for scientific reasoning skills and it could be used for analyzing problems be applied to each situation for more successful and suitable. The purposes of this research aimed to compare learning achievement, analytical thinking and moral reasoning of seventh grade students who were organized between socioscientific issues-based learning and conventional learning activities. Approach: The samples used in research we...

  18. Socioscientific Issues and Multidisciplinarity in School Science Textbooks

    Science.gov (United States)

    Morris, Helen

    2014-05-01

    The inclusion of socioscientific issues (SSIs) in the science curriculum is a well-established trend internationally. Apart from claims about its innate value, one of the rationales for this approach is its potential for helping to counter declining interest and participation. SSIs involve the use of science and are of interest to society, also raising ethical and moral dilemmas. Introducing such problems presents a significant and usually cross-disciplinary challenge to curriculum developers and teachers. The aim of this paper is to examine how this challenge has been met when judged against contemporary views of the issues concerned. It first explores how SSIs have been interpreted in an important and innovative science course for students aged 14-16 in England, entitled Twenty First Century Science. This paper analyses the Twenty First Century Science textbooks, focusing in detail on two SSIs, reproductive genetic technology and climate change. For each of these issues, the key ideas present in the social science literature surrounding the problems are outlined. This review is then used as an analytical framework to examine how the issues are presented in the textbooks. It is argued in this paper that the perspectives the textbooks take on these issues largely do not include perspectives from social science disciplines. It goes on to suggest that the development of future SSI-based curricula needs to take account of these wider, often interdisciplinary, perspectives.

  19. Teaching Controversial Socio-Scientific Issues in Biology and Geology Classes: A Case Study

    OpenAIRE

    Reis, Pedro; Galvão, Cecília

    2009-01-01

    Several educators in science have called for the inclusion of controversial socio-scientific issues’ discussion in science curricula because of its potential for creating a more real, humane image of scientific activity and for promoting scientific literacy, an essential tool for a responsible citizenship regarding decision-making processes related to socio-scientific issues. However, despite all the favourable opinions and empirical evidence concerning the educational potentia...

  20. Saudi Science Teachers' Views and Teaching Strategies of Socioscientific Issues

    Science.gov (United States)

    Alamri, Aziz S.

    Scientific developments such as cloning and nuclear energy have generated many controversial issues pertain to many political, social, environmental, ethical and cultural values in different societies around the globe. These controversies delimited and encircled the potential of including and teaching some important aspects of science in schools and therefore caused less consideration to the influence of these issues on enhancing the scientific literacy of people in general. The purpose of this study was to investigate how Saudi science teachers in the city of Tabuk in Saudi Arabia view and teach SSI in Saudi Arabia. This study employed semi-structured interviews with Saudi science teachers. Methodologically, this study used a constructivist grounded theory as a method for analysis to generate in-depth descriptive data about Saudi science teachers' views and teaching strategies of socio-scientific issues. Some direct and indirect benefits pertain to teaching science, understanding the relationship between science, religion, and society and some other topics are discussed in this study.

  1. "It's Still Science but Not Like Normal Science": Girls' Responses to the Teaching of Socio-Scientific Issues

    Science.gov (United States)

    Morris, Helen

    2014-01-01

    Socio-scientific issues, which are often controversial, involve the use of science and are of interest to society, raising ethical and moral dilemmas. Examples of these issues could include genetic technology or air pollution. Following a curriculum reform in England in 2006, socioscientific issues now have a heightened presence in the 14-16…

  2. Students' Use of Decision-Making Strategies with Regard to Socioscientific Issues: An Application of the Rasch Partial Credit Model

    Science.gov (United States)

    Eggert, Sabina; Bogeholz, Susanne

    2010-01-01

    Decision making about socioscientific issues is an important aspect of modern science education worldwide. Among the many topics that represent socioscientific issues, issues relating to the sustainable development of our environment are one crucial topic. However, difficulties exist with respect to the assessment of teaching outcomes related to…

  3. Development of Lesson Plans and Student Worksheets Based Socio-Scientific Issues on Pollution Environmental Topic

    Science.gov (United States)

    Rahayu, S.; Meyliana, M.; Arlingga, A.; Reny, R.; Siahaan, P.; Hernani, H.

    2017-09-01

    The aim of this study is to develop lesson plans and student worksheets based socio-scientific issues on pollution environmental topic for seventh-grade junior high school students. Environmental pollution topic split into several subtopics namely air pollution, water pollution and soil pollution. The composing of lesson plans were developed based on socio-scientific issues with five stages, namely (1) Motivate; (2) Challenge; (3) Collect scientific evidence; (4) Analyse the evidence; (5) Build knowledge and make connections; and (6) Use evidence. While student worksheets contain articles on socio-scientific issues, practice, and there are a few questions to determine students’ reasoning. The method that is used in this research is research and development (R & D method). Development model used in this study is a model of Plomp that consists of four stages, namely: (1) Initial Research; (2) Design; (3) Realization or Construction; (4) Testing, evaluation and revision; (5) Implementation, while the research was limited to the fourth stage. Lesson plans and student worksheets based on socio-scientific issues was validated through an expert validation. The result showed that lesson plans and student worksheets based socio-scientific issues on pollution theme have a very decent and be able to apply in science classroom.

  4. Case Studies of Secondary School Teachers Designing Socioscientific Issues-Based Instruction and Their Students' Socioscientific Reasoning

    Science.gov (United States)

    Karahan, Engin

    Addressing socioscientific issues (SSI) has been one of the main focuses in science education since the Science, Technology, and Society (STS) movement in the 1970s (Levinson, 2006); however, teaching controversial socioscientific issues has always been challenging for teachers (Dillon, 1994; Osborne, Duschl, & Fairbrother, 2002). Although teachers exhibit positive attitudes for using controversial socioscientific issues in their science classrooms, only a small percentage of them actually incorporate SSI content into their science curricula on a regular basis (Sadler, Amirshokoohi, Kazempour, & Allspaw, 2006; Lee & Witz, 2009). The literature in science education has highlighted the signi?cant relationships among teacher beliefs, teaching practices, and student learning (Bryan & Atwater, 2002; King, Shumow, & Lietz, 2001; Lederman, 1992). Despite the fact that the case studies present a relatively detailed picture of teachers' values and motivations for teaching SSI (e.g. Lee, 2006; Lee & Witz, 2009; Reis & Galvao, 2004), these studies still miss the practices of these teachers and potential outcomes for their students. Therefore, there is a great need for in-depth case studies that would focus on teachers' practices of designing and teaching SSI-based learning environments, their deeper beliefs and motivations for teaching SSI, and their students' response to these practices (Lee, 2006). This dissertation is structured as three separate, but related, studies about secondary school teachers' experiences of designing and teaching SSI-based classes and their students' understanding of science and SSI reasoning. The case studies in this dissertation seek answers for (1) teachers' practices of designing and teaching SSI-based instruction, as well as its relation to their deeper personal beliefs and motivations to teach SSI, and (2) how their students respond to their approaches of teaching SSI in terms of their science understanding and SSI reasoning. The first paper

  5. Moral Sensitivity and Its Contribution to the Resolution of Socio-Scientific Issues

    Science.gov (United States)

    Sadler, Troy

    2004-01-01

    This study explores models of how people perceive moral aspects of socio-scientific issues. Thirty college students participated in interviews during which they discussed their reactions to and resolutions of two genetic engineering issues. The interview data were analyzed qualitatively to produce an emergent taxonomy of moral concerns recognized…

  6. A Framework for Teachers' Assessment of Socio-Scientific Argumentation: An Example Using the GMO Issue

    Science.gov (United States)

    Christenson, Nina; Chang Rundgren, Shu-Nu

    2015-01-01

    Socio-scientific issues (SSI) have proven to be suitable contexts for students to actively reflect on and argue about complex social issues related to science. Research has indicated that explicitly teaching SSI argumentation is a good way to help students develop their argumentation skills and make them aware of the complexity of SSI. However,…

  7. Students' Reasoning Processes in Making Decisions about an Authentic, Local Socio-Scientific Issue: Bat Conservation

    Science.gov (United States)

    Lee, Yeung Chung; Grace, Marcus

    2010-01-01

    Education for scientific literacy entails the development of scientific knowledge and the ability to apply this knowledge and value judgments to decisions about real-life issues. This paper reports an attempt to involve secondary level biology students in making decisions about an authentic socio-scientific issue--that of bat conservation--through…

  8. Licensing issues for inherently safe fast reactors

    International Nuclear Information System (INIS)

    Kastenberg, W.E.; Lee, S.; Okrent, D.

    1986-01-01

    There has been considerable interest recently in a new generation of liquid metal reactor (LMR) concepts in the US. Some significant changes in regulatory philosophy will be required if the anticipated cost advantages of inherently safe designs are to be achieved. The defense in depth philosophy will need to be significantly re-evaluated in the context of inherently safe reactors. It is the purpose of this paper to begin such a re-evaluation of this regulatory philosophy

  9. Science teachers teaching socioscientific issues (SSI): Four case studies

    Science.gov (United States)

    Lee, Hyunju

    Socioscientific issues (SSI) are a class of issues that represent the social, ethical, and moral aspects of science in society. The need for the inclusion of SSI into science curricula has been generally accepted, but relatively few science teachers have incorporated SSI into their courses. Most science teachers feel that their most important task by far is to teach the principles of science, and any substantive pedagogical changes represent a burden. However, there are some teachers who address SSI out of personal initiatives. This dissertation study investigates four high school science teachers who address SSI out of their own initiative and explores their deeper inspirations, values, philosophies, and personal ideals that lead them to teach SSI. The overall approach is based on essentialist methodology (Witz, Goodwin, Hart, & Thomas, 2001; Witz, 2006a) with its focus on "the participant as ally" and "essentialist portraiture." The primary data source is four to six in-depth interviews with individual teachers (about 40-90 minutes for each interview). The interviews are complemented by extensive classroom observations of individual teachers' teaching SSI and by document analysis (including teaching materials, rubrics, student group projects and journals, etc.). There are two major findings. First, the teachers' deeper values and ideals are a source of larger inspiration that plays a significant role in changing their teaching practice. This inspiration may involve higher aspects (e.g., deep concern for students' development, unselfishness, caring, etc.) and commitment. Their teaching represents an integration of their personal experiences, values, concerns, and worldviews, which forms a larger inspiration for teaching. Teaching SSI is a part of this larger process. Second, the current curriculum reforms (STS, SSI, and NOS) only suggest theoretical ideals and do not effectively touch teachers' deeper values and ideals. Basically, the teachers are doing what they

  10. Nutrition Labelling: Applying Biological Concepts and Reasoning to Socio-Scientific Issues

    Science.gov (United States)

    Lee, Yeung Chung

    2016-01-01

    Nutrition labelling, which helps consumers to make informed choices, can be used as both a context and a vehicle for students to consolidate and apply their knowledge of food and nutrition to improve health. It also facilitates students' ability to negotiate socio-scientific issues from scientific and other perspectives. This article reports a…

  11. Turkish Preservice Science Teachers' Socioscientific Issues-Based Teaching Practices in Middle School Science Classrooms

    Science.gov (United States)

    Genel, Abdulkadir; Topçu, Mustafa Sami

    2016-01-01

    Background: Despite a growing body of research and curriculum reforms including socioscientific issues (SSI) across the world, how preservice science teachers (PST) or in-service science teachers can teach SSI in science classrooms needs further inquiry. Purpose: The purpose of this study is to describe the abilities of PSTs to teach SSI in middle…

  12. Introducing Argumentation About Climate Change Socioscientific Issues in a Disadvantaged School

    Science.gov (United States)

    Dawson, Vaille; Carson, Katherine

    2018-03-01

    Improving the ability of young people to construct arguments about controversial science topics is a desired outcome of science education. The purpose of this research was to evaluate the impact of an argumentation intervention on the socioscientific issue of climate change with Year 10 students in a disadvantaged Australian school. After participation in a professional development workshop on climate change science, socioscientific issues and argumentation, an early career teacher explicitly taught argumentation over four non-consecutive lessons as part of a 4 week (16 lesson) topic on Earth science. Thirty students completed a pre- and post-test questionnaire to determine their understanding of climate change science and their ability to construct an argument about a climate change socioscientific issue. Students' understanding of climate change improved significantly (p size. There was also a significant increase (p Qualitative data, comprising classroom observation field notes, lesson transcripts, work samples, and teacher and student interviews, were analysed for the extent to which the students' argumentation skills improved. At the end of the intervention, students became aware of the need to justify their decisions with scientific evidence. It is concluded that introducing argumentation about climate change socioscientific issues to students in a disadvantaged school can improve their argumentation skills.

  13. Science Teachers' Use of Mass Media to Address Socio-Scientific and Sustainability Issues

    Science.gov (United States)

    Klosterman, Michelle L.; Sadler, Troy D.; Brown, Julie

    2012-01-01

    The currency, relevancy and changing nature of science makes it a natural topic of focus for mass media outlets. Science teachers and students can capitalize on this wealth of scientific information to explore socio-scientific and sustainability issues; however, without a lens on how those media are created and how representations of science are…

  14. Promoting the Role of the Personal Narrative in Teaching Controversial Socio-Scientific Issues

    Science.gov (United States)

    Levinson, Ralph

    2008-01-01

    Citizens participating in contemporary socio-scientific issues (SSI) need to draw on local knowledge and personal experience. If curricular developments in the teaching of controversial SSI are to reflect contemporary notions of citizenship then the personal narrative is an indispensable instrument in bridging the gap between the local/personal…

  15. Contextualization of Nature of Science within the Socioscientific Issues Framework: A Review of Research

    Science.gov (United States)

    Karisan, Dilek; Zeidler, Dana L.

    2017-01-01

    The aim of this paper is to examine the importance of contextualization of Nature of Science (NOS) within the Socioscientific Issues (SSI) framework, because of the importance to science education. The emphasis on advancing scientific literacy is contingent upon a robust understanding and appreciation of NOS, as well as the acquisition of…

  16. A Pedagogical Model for Ethical Inquiry into Socioscientific Issues in Science

    Science.gov (United States)

    Saunders, Kathryn J.; Rennie, Leonie J.

    2013-01-01

    Internationally there is concern that many science teachers do not address socioscientific issues (SSI) in their classrooms, particularly those that are controversial. However with increasingly complex, science-based dilemmas being presented to society, such as cloning, genetic screening, alternative fuels, reproductive technologies and…

  17. Prospective Elementary School Teachers’ Views about Socioscientific Issues: A Concurrent Parallel Design Study

    Directory of Open Access Journals (Sweden)

    Muhammet ÖZDEN

    2015-06-01

    Full Text Available The purpose of this research is to examine the prospective elementary school teachers’ perceptions on socioscientific issues. The research was conducted on prospective elementary school teachers studying at a university located in western Turkey. The researcher first taught the subjects of global warming and nuclear power plants from a perspective of socioscientific issues in the science and technology education course and then conducted the research. Concurrent parallel design, one of the mixed-method research approaches, was used to conduct the research. In this context, semi-structured interviews were conducted with eight teachers in the qualitative strand of the study to explore the phenomenon. The data obtained from the interviews were analyzed using thematic analysis. During the quantitative strand of the research, 113 prospective teachers were administered a questionnaire form. The results of the study revealed that none of the participating prospective teachers mentioned about the religious and cultural characteristics of socioscientific issues, and they need training about how to use socioscientific issues in teaching.

  18. Prospective elementary school teachers’ views about socioscientific issues: A concurrent parallel design study

    Directory of Open Access Journals (Sweden)

    Muhammet Özden

    2015-07-01

    Full Text Available The purpose of this research is to examine the prospective elementary school teachers’ perceptions on socioscientific issues. The research was conducted on prospective elementary school teachers studying at a university located in western Turkey. The researcher first taught the subjects of global warming and nuclear power plants from a perspective of socioscientific issues in the science and technology education course and then conducted the research. Concurrent parallel design, one of the mixed-method research approaches, was used to conduct the research. In this context, semi-structured interviews were conducted with eight teachers in the qualitative strand of the study to explore the phenomenon. The data obtained from the interviews were analyzed using thematic analysis. During the quantitative strand of the research, 113 prospective teachers were administered a questionnaire form. The results of the study revealed that none of the participating prospective teachers mentioned about the religious and cultural characteristics of socioscientific issues, and they need training about how to use socioscientific issues in teaching.

  19. Enhancing Students' Communication Skills in the Science Classroom through Socioscientific Issues

    Science.gov (United States)

    Chung, Yoonsook; Yoo, Jungsook; Kim, Sung-Won; Lee, Hyunju; Zeidler, Dana L.

    2016-01-01

    Communication skills are one of the most important competencies for 21st century global citizens. Our guiding presupposition was that socioscientific issues (SSIs) could be used as an effective pedagogical tool for promoting students' communication skills by increasing peer interactions, stimulating students' reasoning, and in constructing shared…

  20. Thai Pre-Service Science Teachers' Struggles in Using Socio-Scientific Issues (SSIs) during Practicum

    Science.gov (United States)

    Pitiporntapin, Sasithep; Yutakom, Naruemon; Sadler, Troy D.

    2016-01-01

    In educational reform, teaching through socio-scientific issues (SSIs) is considered the best way to promote scientific literacy for citizenship as the goal of science teaching. To bring SSIs into the science classroom, Thai pre-service science teachers (PSTs) are expected to understand the concept of SSI-based teaching and to use it effectively…

  1. Teaching with Socio-Scientific Issues in Physical Science: Teacher and Students' Experiences

    Science.gov (United States)

    Talens, Joy

    2016-01-01

    Socio-scientific issues (SSI) are recommended by many science educators worldwide for learners to acquire first hand experience to apply what they learned in class. This investigated experiences of teacher-researcher and students in using SSI in Physical Science, Second Semester, School Year 2012-2013. Latest and controversial news articles on…

  2. Students' Reasoning and Decision Making about a Socioscientific Issue: A Cross-Context Comparison

    Science.gov (United States)

    Lee, Yeung Chung; Grace, Marcus

    2012-01-01

    It has been argued that decision making about socioscientific issue (SSIs) necessitates informal reasoning, which involves multiperspective thinking and moral judgment. This study extends the scope of the literature concerning students' reasoning on SSIs to a cross-contextual study by comparing decisions made on avian flu by 12-13-year-old Chinese…

  3. Turkish Preservice Science Teachers' Informal Reasoning regarding Socioscientific Issues and the Factors Influencing Their Informal Reasoning

    Science.gov (United States)

    Topcu, Mustafa Sami; Yilmaz-Tuzun, Ozgul; Sadler, Troy D.

    2011-01-01

    The purpose of the study is to explore Turkish preservice science teachers' informal reasoning regarding socioscientific issues and the factors influencing their informal reasoning. The researchers engaged 39 preservice science teachers in informal reasoning interview and moral decision-making interview protocols. Of the seven socioscientific…

  4. Post It!--A Cross-Disciplinary Approach to Teach Socioscientific Issues

    Science.gov (United States)

    Rundgren, Shu-Nu Chang

    2011-01-01

    Various socioscientific issues (SSIs) are emerging in today's science--and technology--dominant society, e.g. genetically modified organisms and global warming. To achieve the goal of scientific literacy, more and more science educators have devoted their attention to enhancing students' understanding of the multidimensional aspects of SSIs as…

  5. Socioscientific Issues-Based Instruction: An Investigation of Agriscience Students' Content Knowledge Based on Student Variables

    Science.gov (United States)

    Shoulders, Catherine W.; Myers, Brian E.

    2013-01-01

    Numerous researchers in science education have reported student improvement in areas of scientific literacy resulting from socioscientific issues (SSI)-based instruction. The purpose of this study was to describe student agriscience content knowledge following a six-week SSI-based instructional unit focusing on the introduction of cultured meat…

  6. Preservice Science Teachers' Efficacy Regarding a Socioscientific Issue: A Belief System Approach

    Science.gov (United States)

    Kilinç, Ahmet; Kartal, Tezcan; Eroglu, Baris; Demiral, Ümit; Afacan, Özlem; Polat, Dilber; Demirci Guler, Mutlu P.; Görgülü, Özkan

    2013-01-01

    The aim of the present study was to understand the nature of teaching efficacy beliefs related to a socioscientific issue (SSI). We investigated Turkish preservice science teachers' teaching efficacy beliefs about genetically modified (GM) foods using a belief system approach. We assumed that preservice teachers' beliefs about GM foods (content…

  7. Students' Argumentation Skills across Two Socio-Scientific Issues in a Confucian Classroom: Is Transfer possible?

    Science.gov (United States)

    Foong, Chan-Choong; Daniel, Esther G. S.

    2013-01-01

    This paper argues the possible simultaneous development and transfer of students' argumentation skills from one socio-scientific issue to another in a Confucian classroom. In Malaysia, the Chinese vernacular schools follow a strict Confucian philosophy in the teaching and learning process. The teacher talks and the students listen. This case study…

  8. The Significance of Content Knowledge for Informal Reasoning regarding Socioscientific Issues: Applying Genetics Knowledge to Genetic Engineering Issues

    Science.gov (United States)

    Sadler, Troy D.; Zeidler, Dana L.

    2005-01-01

    This study focused on informal reasoning regarding socioscientific issues. It sought to explore how content knowledge influenced the negotiation and resolution of contentious and complex scenarios based on genetic engineering. Two hundred and sixty-nine students drawn from undergraduate natural science and nonnatural science courses completed a…

  9. Pre-service Science Teachers’ Self-efficacy Beliefs to Teach Socio-scientific Issues

    OpenAIRE

    Muğaloğlu, Ebru Z.; Küçük, Zerrin Doğança; Güven, Devrim

    2016-01-01

    This study aims to examine self-efficacy of pre-service science teachers to teach socio-scientific issues (SSI). Twenty-three senior pre-service science teachers participated in the study. Science Teaching Efficacy Belief Instrument (STEBI) was modified with an emphasis on SSI rather than scientific issues. The modified STEBI was applied to the participants before and after the intervention. As for the six-week intervention, three modules, which focused on understanding nature of SSI, teachin...

  10. The use of narrative in supporting the teaching of socio-scientific issues: a study of teachers’ reflections

    OpenAIRE

    Levinson, Ralph

    2006-01-01

    While narratives which integrate aspects of human consciousness can be a powerful instrument in teaching and learning about socio-scientific issues, the science curriculum offers unfruitful grounds for the development of narrative in school students. Learning science and learning about socio-scientific issues are epistemologically distinct activities. The way teachers across the curriculum use narratives suggests that an interdisciplinary approach might be more effective for te...

  11. Turkish Preservice Science Teachers' Informal Reasoning Regarding Socioscientific Issues and the Factors Influencing Their Informal Reasoning

    Science.gov (United States)

    Topçu, Mustafa Sami; Yılmaz-Tüzün, Özgül; Sadler, Troy D.

    2011-06-01

    The purpose of the study is to explore Turkish preservice science teachers' informal reasoning regarding socioscientific issues and the factors influencing their informal reasoning. The researchers engaged 39 preservice science teachers in informal reasoning interview and moral decision-making interview protocols. Of the seven socioscientific issues, three issues were related to gene therapy, another three were related to human cloning, and one was related to global warming. The data were analyzed using an interpretive qualitative research approach. The characteristic of informal reasoning was determined as multidimensional, and the patterns of informal reasoning emerged as rationalistic, emotive, and intuitive reasoning. The factors influencing informal reasoning were: personal experiences, social considerations, moral-ethical considerations, and technological concerns.

  12. Scepticism and Trust: Two Counterpoint Essentials in Science Education for Complex Socio-Scientific Issues

    Science.gov (United States)

    Fensham, Peter J.

    2014-01-01

    In this response to Tom G. K. Bryce and Stephen P. Day's ("Cult Stud Sci Educ." doi:10.1007/s11422-013-9500-0, 2013) original article, I share with them their interest in the teaching of climate change in school science, but I widen it to include other contemporary complex socio-scientific issues that also need to be discussed. I…

  13. Enhancing nature of science understanding, reflective judgment, and argumentation through socioscientific issues

    Science.gov (United States)

    Callahan, Brendan E.

    There is a distinct divide between theory and practice in American science education. Research indicates that a constructivist philosophy, in which students construct their own knowledge, is conductive to learning, while in many cases teachers continue to present science in a more traditional manner. This study sought to explore possible relationships between a socioscientific issues based curriculum and three outcome variables: nature of science understanding, reflective judgment, and argumentation skill. Both quantitative and qualitative methods were used to examine both whole class differences as well as individual differences between the beginning and end of a semester of high school Biology I. Results indicated that the socioscientific issues based curriculum did not produce statistically significant changes over the course of one semester. However, the treatment group scored better on all three instruments than the comparison group. The small sample size may have contributed to the inability to find statistical significance in this study. The qualitative interviews did indicate that some students provided more sophisticated views on nature of science and reflective judgment, and were able to provide slightly more complex argumentation structures. Theoretical implications regarding the use of explicit use of socioscientific issues in the classroom are presented.

  14. Socio-Scientific Controversial Issues in 1st Cycle of Basic Education

    Directory of Open Access Journals (Sweden)

    Fábio Ribeiro

    2014-12-01

    Full Text Available Assuming the importance of science education, from early years, aiming to educate citizens capable of thinking critically and act in scientific and technological contexts, a study was carried out in order to develop learning situations focused on controversial socio-scientific issues to promote students’ argumentation skills and scientific knowledge building / mobilization. The study was based on a qualitative methodology, following an action research plan. It was conducted with a class of 3th grade, having been addressed controversial socio-scientific issues, framed in science curriculum topics, using strategies of debate, role-play and argumentative essays. Data was collected using an analyzing instrument of student´s oral and written productions. In data analysis the privileged technique was content analysis. The results suggest that students mobilized requested scientific knowledge, showing improvement in the effective use of argumentation skills required. This allows us to conclude that the approach of controversial socio-scientific issues contributes to the promotion students´ argumentation skills as well as for scientific knowledge construction / mobilization.

  15. The Effect of Using Socio-Scientific Issues Approach in Teaching Environmental Issues on Improving the Students' Ability of Making Appropriate Decisions towards These Issues

    Science.gov (United States)

    Zo'bi, Abdallah Salim

    2014-01-01

    This study aimed to identify nature of students' decisions patterns towards environmental issues and the possibility to improve these decisions during teaching process using Socio-Scientific Issues Approach. And to achieve this, the researcher prepared and developed tools of the study represented by a test of open questions focused on…

  16. Learning as change: Responding to socio-scientific issues through informal education

    Science.gov (United States)

    Allen, Lauren Brooks

    Informal learning is an important venue for educating the general public about complex socio-scientific issues: intersections of scientific understanding and society. My dissertation is a multi-tiered analysis of how informal education, and particularly informal educators, can leverage learning to respond to one particular socio-scientific issue: climate change. Life-long, life-wide, and life-deep learning not only about the science of climate change, but how communities and society as a whole can respond to it in ways that are commensurate with its scale are necessary. In my three-article dissertation, I investigated the changes in practice and learning that informal educators from a natural history museum underwent in the process of implementing a new type of field trip about climate change. This study focused on inquiry-based learning principles taken on by the museum educators, albeit in different ways: learner autonomy, conversation, and deep investigation. My second article, a short literature review, makes the argument that climate change education must have goals beyond simply increasing learners' knowledge of climate science, and proposes three research-based principles for such learning: participation, relevance, and interconnectedness. These principles are argued to promote learning to respond to climate change as well as increased collective efficacy, necessary for responding. Finally, my third article is an in-depth examination of a heterogeneous network of informal educators and environmental professionals who worked together to design and implement a city-wide platform for informal climate change learning. By conceptualizing climate change learning at the level of the learning ecology, educators and learners are able to see how it can be responded to at the community level, and understand how climate change is interconnected with other scientific, natural, and social systems. I briefly discuss a different socio-scientific issue to which these

  17. Analysis of students critical thinking skills in socio-scientific issues of biodiversity subject

    Science.gov (United States)

    Santika, A. R.; Purwianingsih, W.; Nuraeni, E.

    2018-05-01

    Critical thinking is a skills the which students should have in order to face 21st century demands. Critical thinking skills can help people in facing their daily problems, especially problems roommates relate to science. This research is aimed to analyze students critical thinking skills in socio-scientific issues of biodiversity subject. The method used in this research was descriptive method. The research subject is first-grade students’ in senior high school. The data collected by interview and open-ended question the which classified based on framework : (1) question at issue, (2) information (3) purpose (4) concepts (5) assumptions, (6) point of view, (7) interpretation and inference, and (8) implication and consequences, then it will be assessed by using rubrics. The result of the data showed students critical thinking skills in socio-scientific issues of biodiversity subject is in low and medium category. Therefore we need a learning activity that is able to develop student’s critical thinking skills, especially regarding issues of social science.

  18. A Pedagogical Model for Ethical Inquiry into Socioscientific Issues In Science

    Science.gov (United States)

    Saunders, Kathryn J.; Rennie, Léonie J.

    2013-02-01

    Internationally there is concern that many science teachers do not address socioscientific issues (SSI) in their classrooms, particularly those that are controversial. However with increasingly complex, science-based dilemmas being presented to society, such as cloning, genetic screening, alternative fuels, reproductive technologies and vaccination, there is a growing call for students to be more scientifically literate and to be able to make informed decisions on issues related to these dilemmas. There have been shifts in science curricula internationally towards a focus on scientific literacy, but research indicates that many secondary science teachers lack the support and confidence to address SSI in their classrooms. This paper reports on a project that developed a pedagogical model that scaffolded teachers through a series of stages in exploring a controversial socioscientific issue with students and supported them in the use of pedagogical strategies and facilitated ways of ethical thinking. The study builds on existing frameworks of ethical thinking. It presents an argument that in today's increasingly pluralistic society, these traditional frameworks need to be extended to acknowledge other worldviews and identities. Pluralism is proposed as an additional framework of ethical thinking in the pedagogical model, from which multiple identities, including cultural, ethnic, religious and gender perspectives, can be explored.

  19. A Comparison Study of Augmented Reality versus Interactive Simulation Technology to Support Student Learning of a Socio-Scientific Issue

    Science.gov (United States)

    Chang, Hsin-Yi; Hsu, Ying-Shao; Wu, Hsin-Kai

    2016-01-01

    We investigated the impact of an augmented reality (AR) versus interactive simulation (IS) activity incorporated in a computer learning environment to facilitate students' learning of a socio-scientific issue (SSI) on nuclear power plants and radiation pollution. We employed a quasi-experimental research design. Two classes (a total of 45…

  20. The Integration of HIV and AIDS as a Socio-Scientific Issue in the Life Sciences Curriculum

    Science.gov (United States)

    Wolff, Eugenie; Mnguni, Lindelani

    2015-01-01

    The potential of science to transform lives has been highlighted by a number of scholars. This means that critical socio-scientific issues (SSIs) must be integrated into science curricula. Development of context-specific scientific knowledge and twenty-first-century learning skills in science education could be used to address SSIs such as…

  1. Learning Science Content through Socio-Scientific Issues-Based Instruction: A Multi-Level Assessment Study

    Science.gov (United States)

    Sadler, Troy D.; Romine, William L.; Topçu, Mustafa Sami

    2016-01-01

    Science educators have presented numerous conceptual and theoretical arguments in favor of teaching science through the exploration of socio-scientific issues (SSI). However, the empirical knowledge base regarding the extent to which SSI-based instruction supports student learning of science content is limited both in terms of the number of…

  2. Using Social Media to Promote Pre-Service Science Teachers' Practices of Socio-Scientific Issue (SSI) - Based Teaching

    Science.gov (United States)

    Pitiporntapin, Sasithep; Lankford, Deanna Marie

    2015-01-01

    This paper addresses using social media to promote pre-service science teachers' practices of Socio-Scientific Issue (SSI) based teaching in a science classroom setting. We designed our research in two phases. The first phase examined pre-service science teachers' perceptions about using social media to promote their SSI-based teaching. The…

  3. Students' Socioscientific Reasoning and Decision-Making on Energy-Related Issues--Development of a Measurement Instrument

    Science.gov (United States)

    Sakschewski, Mark; Eggert, Sabina; Schneider, Susanne; Bögeholz, Susanne

    2014-01-01

    The concept of energy is one key component of science education curricula worldwide. While it is still being taught in many science classrooms from a mainly conceptual knowledge perspective, the need to frame the concept of energy as a socioscientific issue and implement it in the context of citizenship education and education for sustainable…

  4. Training in Decision-Making Strategies: An Approach to Enhance Students' Competence to Deal with Socio-Scientific Issues

    Science.gov (United States)

    Gresch, Helge; Hasselhorn, Marcus; Bögeholz, Susanne

    2013-01-01

    Dealing with socio-scientific issues in science classes enables students to participate productively in controversial discussions concerning ethical topics, such as sustainable development. In this respect, well-structured decision-making processes are essential for elaborate reasoning. To foster decision-making competence, a computer-based…

  5. Students' Environmental NOS Views, Compassion, Intent, and Action: Impact of Place-Based Socioscientific Issues Instruction

    Science.gov (United States)

    Herman, Benjamin C.

    2018-01-01

    Preparing students to achieve the lofty goal of functional scientific literacy entails addressing the normative and non-normative facets of socioscientific issues (SSI) such as scientific processes, the nature of science (NOS) and diverse sociocultural perspectives. SSI instructional approaches have demonstrated some efficacy for promoting…

  6. Argumentation as a Strategy for Increasing Preservice Teachers' Understanding of Climate Change, a Key Global Socioscientific Issue

    Science.gov (United States)

    Lambert, Julie L.; Bleicher, Robert E.

    2017-01-01

    Findings of this study suggest that scientific argumentation can play an effective role in addressing complex socioscientific issues (i.e. global climate change). This research examined changes in preservice teachers' knowledge and perceptions about climate change in an innovative undergraduate-level elementary science methods course. The…

  7. Rhetorical Use of Inscriptions in Students' Written Arguments About Socioscientific Issues

    Science.gov (United States)

    Xiao, Sihan

    2018-05-01

    Educators expect that students be able to make informed decisions about science-related problems in their everyday lives. Engaging science in such problems often entails evaluating available evidence for given arguments. This study explores how students use inscriptions as evidence to argue about socioscientific issues. Fifth- and sixth-grade students (N = 102) in two intact classrooms completed written argument tasks in which they were asked to cite given inscriptions to support their decisions about energy use or genetically modified organisms. Qualitative content analyses of these written arguments, which focused on the coordination between inscriptions and claims, show three patterns of rhetorical use of inscriptions: seeing is believing, believing is seeing, and asserting is inferring. What counts as evidence was not the inscriptions per se, but the rhetorical functions they performed in particular arguments. These findings suggest that justifying socioscientific decisions is functionally different from explaining scientific phenomena. Linking these two activities in school may help students more productively engage with science in their everyday lives.

  8. Body talk: students' identity construction while discussing a socioscientific issue

    Science.gov (United States)

    Ideland, Malin; Malmberg, Claes

    2012-06-01

    Vision II school science is often stated to be a democratic and inclusive form of science education. But what characterizes the subject who fits into the Vision II school science? Who is the desirable student and who is constructed as ill-fitting? This article explores discourses that structure the Vision II science classroom, and how different students construct their identities inside these discourses. In the article we consider school science as an order of discourses which restricts and enables what is possible to think and say and what subject-positions those are available and non-available. The results show that students' talk about a SSI about body and health is constituted by several discourses. We have analyzed how school science discourse, body discourse and general school discourse are structuring the discussions. But these discourses are used in different ways depending on how the students construct their identities in relation to available subject positions, which are dependent on how students at the same time are "doing" gender and social class. As an example, middle class girls show resistance against SSI-work since the practice is threatening their identity as "successful students". This article uses a sociopolitical perspective in its discussions on inclusion and exclusion in the practice of Vision II. It raises critical issues about the inherited complexity of SSI with meetings and/or collisions between discourses. Even if the empirical results from this qualitative study are situated in specific cultural contexts, they contribute with new questions to ask concerning SSI and Vision II school science.

  9. Engaging Elementary School Pre-service Teachers in Modeling a Socioscientific Issue as a Way to Help Them Appreciate the Social Aspects of Science

    OpenAIRE

    Evagorou, Maria; Puig Mauriz, Blanca

    2017-01-01

    Socioscientific issues are ill-structured problems that involve moral, ethical, and financial aspects, and lack clear-cut solutions. Teaching socioscientific issues necessarily puts a demand on teachers to draw on knowledge stemming from other domains, and to also appreciate, and present to the students the societal aspects of science. For new teachers, and those who have not tried integrating complex social issues into their instruction, SSI-based teaching may seem too great a hurdle to over...

  10. Informal reasoning regarding socioscientific issues: The influence of morality and content knowledge

    Science.gov (United States)

    Sadler, Troy Dow

    This study focused on informal reasoning regarding socioscientific issues. It explored how morality and content knowledge influenced the negotiation and resolution of contentious and complex scenarios based on genetic engineering. Two hundred and sixty-nine undergraduate students completed a quantitative test of genetics concepts. A sub-set of the students (n = 30) who completed this instrument and represented divergent levels of content knowledge participated in two individual interviews, during which they discussed their ideas, reactions, and solutions to three gene therapy scenarios and three cloning scenarios. A mixed-methods approach was used to examine patterns of informal reasoning and the influence of morality, the effects of content knowledge on the use of informal reasoning patterns, and the effects of content knowledge on the quality of informal reasoning. Students demonstrated evidence of rationalistic, emotive, and intuitive forms of informal reasoning. Rationalistic informal reasoning described reason-based considerations; emotive informal reasoning described care-based considerations; and intuitive reasoning described considerations based on immediate reactions to the context of a scenario. Participants frequently relied on combinations of these reasoning patterns as they worked to resolve individual socioscientific scenarios. Most of the participants appreciated at least some of the moral implications of their decisions, and these considerations were typically interwoven within an overall pattern of informal reasoning. Although differences in content knowledge were not found to be related to modes of informal reasoning (rationalistic, emotive, and informal), data did indicate that differences in content knowledge were related to variations in informal reasoning quality. Participants, with more advanced understandings of genetics, demonstrated fewer instances of reasoning flaws, as defined by a priori criteria (intra-scenario coherence, inter

  11. Integrating Bioethics in Sciences’ curricula using values in science and socio-scientific issues

    Directory of Open Access Journals (Sweden)

    C. Sousa

    2017-04-01

    Full Text Available The  The main objective of the present work is selection of ethical issues that should be addressed with first year undergraduate and K-12 students. Since K-12 Sciences’ curriculum, in Portugal, does not include bioethics content in any discipline explicitly, teachers need to make an effort to include it. Some online materials are available to use in high school classes and will be discussed. My proposal combines inquiry learning-teaching methods with the aim of promoting the discussion of bioethics issues in accordance to UNESCO Bioethics Core Curriculum already adopted by twenty universities throughout the world (Darwish 2015. Some of the issues that are addressed are: ecology and environment ethics, infectious diseases and vaccination, water for all, intellectual property, genomes and patents, biotechnological advances (genetic modified organisms and synthesis of genomes, future generations, climate hanges and natural resources, biomedical advances and human rights, authorship and contributions in scientific publications, and biobanks. In conclusion, this study may constitute an example to facilitate the implementation, by K-12 teachers, of active inquiry strategies, using features of science such as values and socio-scientific issues, and focused on the discussion of concrete ethical issues facing humanity. It also constitutes a proposal of integrating Bioethics in undergraduate sciences’ curricula.

  12. Developing Character and Values for Global Citizens: Analysis of pre-service science teachers' moral reasoning on socioscientific issues

    Science.gov (United States)

    Lee, Hyunju; Chang, Hyunsook; Choi, Kyunghee; Kim, Sung-Won; Zeidler, Dana L.

    2012-04-01

    Character and values are the essential driving forces that serve as general guides or points of reference for individuals to support decision-making and to act responsibly about global socioscientific issues (SSIs). Based on this assumption, we investigated to what extent pre-service science teachers (PSTs) of South Korea possess character and values as global citizens; these values include ecological worldview, socioscientific accountability, and social and moral compassion. Eighteen PSTs participated in the SSI programs focusing on developing character and values through dialogical and reflective processes. SSIs were centered on the use of nuclear power generation, climate change, and embryonic stem cell research. The results indicated that PSTs showed three key elements of character and values, but failed to apply consistent moral principles on the issues and demonstrated limited global perspectives. While they tended to approach the issues with emotion and sympathy, they nonetheless failed to perceive themselves as major moral agents who are able to actively resolve large-scale societal issues. This study also suggests that the SSI programs can facilitate socioscientific reasoning to include abilities such as recognition of the complexity of SSIs, examine issues from multiple perspectives, and exhibit skepticism about information.

  13. Argumentation as a Strategy for Increasing Preservice Teachers’ Understanding of Climate Change, a Key Global Socioscientific Issue

    OpenAIRE

    Lambert, Julie L.; Bleicher, Robert E.

    2017-01-01

    Findings of this study suggest that scientific argumentation can play an effective role in addressing complex socioscientific issues (i.e. global climate change). This research examined changes in preservice teachers’ knowledge and perceptions about climate change in an innovative undergraduate-level elementary science methods course. The preservice teachers’ understanding of fundamental concepts (e.g., the difference between weather and climate, causes of recent global warming, etc.) increas...

  14. Effects of socioscientific issues-based instruction on argumentation ability and biology concepts of upper secondary school students

    Science.gov (United States)

    Faelt, Surasak; Samiphak, Sara; Pattaradilokrat, Sittiporn

    2018-01-01

    Argumentation skill is an essential skill needed in students, and one of the competencies in scientific literacy. Through arguing on socioscientific issues, students may gain deeper conceptual understanding. The purpose of this research is to examine the efficacy of a socioscientific issues-based instruction compared with an inquirybased instruction. This is to determine which one is better in promoting 10th grade students' argumentation ability and biology concepts of digestive system and cellular respiration. The forty 10th grade students included in this study were from two mathematics-science program classes in a medium-sized secondary school located in a suburb of Buriram province, Thailand. The research utilizes a quasi-experimental design; pre-test post-test control group design. We developed and implemented 4 lesson plans for both socioscientific issues-based instruction and inquiry-based instruction. Ten weeks were used to collect the data. A paper-based questionnaire and informal interviews were designed to test students' argumentation ability, and the two-tier multiple-choice test was designed to test their biology concepts. This research explore qualitatively and quantitatively students' argumentation abilities and biology concepts, using arithmetic mean, mean of percentage, standard deviation and t-test. Results show that there is no significant difference between the two group regarding mean scores of the argumentation ability. However, there is significant difference between the two groups regarding mean scores of the biology concepts. This suggests that socioscientific issues-based instruction could be used to improve students' biology concepts.

  15. Progression in Ethical Reasoning When Addressing Socio-scientific Issues in Biotechnology

    Science.gov (United States)

    Berne, Birgitta

    2014-11-01

    This article reports on the outcomes of an intervention in a Swedish school in which the author, a teacher-researcher, sought to develop students' (14-15 years old) ethical reasoning in science through the use of peer discussions about socio-scientific issues. Prior to the student discussions various prompts were used to highlight different aspects of the issues. In addition, students were given time to search for further information themselves. Analysis of students' written arguments, from the beginning of the intervention and afterwards, suggests that many students seem to be moving away from their use of everyday language towards using scientific concepts in their arguments. In addition, they moved from considering cloning and 'designer babies' solely in terms of the present to considering them in terms of the future. Furthermore, the students started to approach the issues in additional ways using not only consequentialism but also the approaches of virtue ethics, and rights and duties. Students' progression in ethical reasoning could be related to the characteristics of the interactions in peer discussions as students who critically and constructively argued with each other's ideas, and challenged each other's claims, made progress in more aspects of ethical reasoning than students merely using cumulative talk. As such, the work provides valuable indications for the importance of introducing peer discussions and debates about SSIs in connection to biotechnology into the teaching of science in schools.

  16. Socio-Scientific Issues in Health Contexts: Treading a rugged terrain

    Science.gov (United States)

    Chung Lee, Yeung

    2012-02-01

    The science-technology-society agenda has evolved over time to meet emerging educational aims in the light of changes in society and the environment. There is increasing emphasis on students' decision-making on socio-scientific issues (SSIs) not only to highlight the intricate relationships between science, technology, society, and the environment, but also to allow students to incorporate multiple viewpoints into the development of critical reasoning and responsible citizenship. Most research emphases have been on the rationality of reasoning rather than on the internal psychological context that underpins reasoning. This paper explores how these various aspects of reasoning interact in decision-making on SSIs in health contexts through case studies of recent issues in this field. The case studies reveal the negotiation of multiple influences in addressing SSIs in health contexts and the potential interactions between the psychological processes of individuals, science, and sociocultural perspectives. A tentative model to address these interactions emerges from this explorative study and has implications for the use of health-related issues in promoting SSI education.

  17. Implementation of Socioscientific Issues Instruction to Fostering Students’ Decision Making Based Gender on Environmental Pollution

    Science.gov (United States)

    Rizal, H. P.; Siahaan, P.; Yuliani, G.

    2017-02-01

    The purpose of this study was to investigate the implementation socioscientific issues (SSI) instruction to examine students’ decision making based gender. Selection of environmental problem based on the consideration this issue has potential to evaluate from various scientific disciplines and may initiate to make decision. The participant was students grade VII in South Sulawesi. Pre experiment method was utilized in study with one group pre-test and post-test design. The instrument used in this study comprised of open-ended question, observation sheets for group discussion, sheet for interview and observation sheet of implementation instruction in class. The result indicated that instruction has been implemented successfully. It was found that pre-test and post-test was fostered with N-gain for male and female in medium category. Based on independent t test was found there was no difference improvement of decision making between male and female students. The group showed there was no difference between male group and female group, but a significant difference was noted in mix group. Students and teacher give positive response to the implementation of instruction. It is concluded that science instruction based SSI can be implemented to foster male and female decision making by forming group discussion.

  18. Argumentation, critical thinking, nature of science and socioscientific issues: a dialogue between two researchers

    Science.gov (United States)

    Yacoubian, Hagop A.; Khishfe, Rola

    2018-05-01

    The purpose of this paper is to compare and contrast between two theoretical frameworks for addressing nature of science (NOS) and socioscientific issues (SSI) in school science. These frameworks are critical thinking (CT) and argumentation (AR). For the past years, the first and second authors of this paper have pursued research in this area using CT and AR as theoretical frameworks, respectively. Yacoubian argues that future citizens need to develop a critical mindset as they are guided to (1) practice making judgments on what views of NOS to acquire and (2) practice making decisions on SSI through applying their NOS understandings. Khishfe asserts that AR is an important component of decision making when dealing with SSI and the practice in AR in relation to controversial issues is needed for informed decision making. She argues that AR as a framework may assist in the development of more informed understandings of NOS. In this paper, the authors delve into a dialogue for (1) elucidating strengths and potential of each framework, (2) highlighting challenges that they face in their research using the frameworks in question, (3) exploring the extent to which the frameworks can overlap, and (4) proposing directions for future research.

  19. Western Australian High School Students' Understandings about the Socioscientific Issue of Climate Change

    Science.gov (United States)

    Dawson, Vaille

    2015-05-01

    Climate change is one of the most significant science issues facing humanity; yet, teaching students about climate change is challenging: not only is it multidisciplinary, but also it is contentious and debated in political, social and media forums. Students need to be equipped with an understanding of climate change science to be able to participate in this discourse. The purpose of this study was to examine Western Australian high school students' understanding of climate change and the greenhouse effect, in order to identify their alternative conceptions about climate change science and provide a baseline for more effective teaching. A questionnaire designed to elicit students' understanding and alternative conceptions was completed by 438 Year 10 students (14-15 years old). A further 20 students were interviewed. Results showed that students know different features of both climate change and the greenhouse effect, however not necessarily all of them and the relationships between. Five categories of alternative conceptions were identified. The categories were (1) the greenhouse effect and the ozone layer; (2) types of greenhouse gases; (3) types of radiation; (4) weather and climate and (5) air pollution. These findings provide science educators a basis upon which to develop strategies and curriculum resources to improve their students' understanding and decision-making skills about the socioscientific issue, climate change.

  20. Argumentation Quality of Socio-scientific Issue between High School Students and Postgraduate Students about Cancer

    Science.gov (United States)

    Anisa, A.; Widodo, A.; Riandi, R.

    2017-09-01

    Argumentation is one factor that can help improve critical thinking skills. Arguing means to defend statements with the various data, denials, evidence, and reinforcement that support the statement. The research aimed to capture the quality of argument skills by students in grade 12 high school students and in postgraduate student on social-scientific issues of cancer. Both group subjects are not in the same school or institution, chosen purposively with the subject of 39 high school students of grade 12 in one district of West Java and 13 students of Biology education postgraduate in one of University in West Java - Indonesia. The results of the quality structure of arguments in both subject groups show the same pattern, which is claim - warrant - and ground, with the quality of counterclaim aspects on the postgraduate students look better than grade 12 students. This provides an illustration that the ability in argumentation between students and teachers in the socio-scientific issue of cancer should be evaluate so that the learning process would be more refined in schools.

  1. Adults' decision-making about the electronic waste issue: The role of the nature of science conceptualizations and moral concerns in socio-scientific decision-making

    Science.gov (United States)

    Yu, Yuqing

    Socio-scientific issues have become increasingly important in Science-Technology-Society (STS) education as a means to make science learning more relevant to students' lives. This study used the e-waste issue as a context to investigate two aspects of socio-scientific decision-making: (1) the relationship between the nature of science (NOS) conceptualizations and decision-making; and (2) moral concerns involved in the process of decision-making. This study contributes to the field of socio-scientific issue research and STS education in the following ways. First, it is the first study that performed meta-analysis to seek the relationship between the NOS understanding and decision-making. This study concludes that valuable NOS conceptualizations that are highly related to the socio-scientific issue under investigation, rather than general NOS understanding, exert statistically significant influences on decision-making. Second, this study empirically examined the Multiple Responses Model (MRM), which enables the transfer of qualitative NOS responses into quantitative data, and hence, inferential statistics. The current study justifies the significance of unidimensionality to the application of the MRM. It addresses the limitations associated with the MRM and provides implications for future use of the MRM in other contexts. Finally, the study explores the role of moral concerns in socio-scientific decision-making. Eight participants engaged in interviews that were designed to elicit their reactions and feelings regarding the issue of exporting e-waste to poor countries. Qualitative analyses demonstrated that moral considerations were significant influences on decision-making. In addition, participants' action responses revealed that they were motivated to take action to help the environment. The study has implications for socio-scientific issue studies in other contexts and for teacher education programs that use socio-scientific issues to advance teachers' reasoning

  2. Socioscientific Issues as a Vehicle for Promoting Character and Values for Global Citizens

    Science.gov (United States)

    Lee, Hyunju; Yoo, Jungsook; Choi, Kyunghee; Kim, Sung-Won; Krajcik, Joseph; Herman, Benjamin C.; Zeidler, Dana L.

    2013-08-01

    Our guiding presupposition in this study was that socioscientific issues (SSI) instruction, given the humanistic features that comprise this type of instruction, could play a role as a vehicle for cultivating character and values as global citizens. Our main objective was to observe how and to what extent SSI instruction might contribute to this. In order to achieve this aim, we implemented a SSI program on genetic modification technology for 132 ninth-grade students over 3-4 weeks and identified its educational effects using a mixed method approach. Data sources included student responses to questionnaire items that measure the students' character and values, records of student discussions, and semi-structured interviews with the students and their teachers. Results indicated that the students became more sensitive to moral and ethical aspects of scientific and technological development and compassionate to diverse people who are either alienated by the benefits of advanced technology or who are vulnerable to the dangers of its unintended effects. In addition, the students felt more responsible for the future resolution of the genetic SSI. However, the students struggled to demonstrate willingness and efficacy to participate within broader communities that entailed action toward SSI resolution.

  3. Scepticism and trust: two counterpoint essentials in science education for complex socio-scientific issues

    Science.gov (United States)

    Fensham, Peter J.

    2014-09-01

    In this response to Tom G. K. Bryce and Stephen P. Day's (Cult Stud Sci Educ. doi: 10.1007/s11422-013-9500-0, 2013) original article, I share with them their interest in the teaching of climate change in school science, but I widen it to include other contemporary complex socio-scientific issues that also need to be discussed. I use an alternative view of the relationship between science, technology and society, supported by evidence from both science and society, to suggest science-informed citizens as a more realistic outcome image of school science than the authors' one of mini-scientists. The intellectual independence of students Bryce and Day assume, and intend for school science, is countered with an active intellectual dependence. It is only in relation to emerging and uncertain scientific contexts that students should be taught about scepticism, but they also need to learn when, and why to trust science as an antidote to the expressions of doubting it. Some suggestions for pedagogies that could lead to these new learnings are made. The very recent fifth report of the IPCC answers many of their concerns about climate change.

  4. Does Evidence Matter? How Middle School Students Make Decisions About Socioscientific Issues

    Science.gov (United States)

    Emery, Katherine Beth

    People worldwide are faced with making decisions daily. While many decisions are quick (e.g., what clothes to wear), others, such as those about environmental issues (e.g., overfishing), require more thought and have less immediate outcomes. How one makes such decisions depends on how one interprets, evaluates, and uses evidence. The central objective of this thesis was to investigate environmental science literacy in general, and specifically, to understand how evidence and other factors impact decision-making. I conducted three main studies: First, I provide an example of how decision-making practices affect environmental systems and services through a descriptive case study of Atlantic bluefin tuna overfishing. I reviewed the scientific, historical and cultural factors contributing to a paradox of marine preservation in the Mediterranean and highlighted the need for education and informed decision-making about such social and ecological issues. This study motivated me to investigate how people make decisions about environmental issues. Second, I interviewed middle school students to understand how they describe and evaluate evidence hypothetically and in practice about environmental issues---a key component of environmental literacy. Students discussed how they would evaluate evidence and then were then given a packet containing multiple excerpts of information from conflicting stakeholders about an environmental issue and asked how they would make voting or purchasing decisions about these issues. Findings showed that students' ideas about evaluating evidence (e.g., by scientific and non-scientific criteria) match their practices in part. This study was unique in that it investigated how students evaluate evidence that (1) contradicts other evidence and (2), conflicts with the student's prior positions. Finally, I investigated whether middle school students used evidence when making decisions about socioscientific issues. I hypothesized that holding a strong

  5. The Relationship of Discipline Background to Upper Secondary Students' Argumentation on Socioscientific Issues

    Science.gov (United States)

    Christenson, Nina; Chang Rundgren, Shu-Nu; Zeidler, Dana L.

    2014-08-01

    In the present STEM (Science, Technology, Engineering, and Mathematics)-driven society, socioscientific issues (SSI) have become a focus globally and SSI research has grown into an important area of study in science education. Since students attending the social and science programs have a different focus in their studies and research has shown that students attending a science program are less familiar with argumentation practice, we make a comparison of the supporting reasons social science and science majors use in arguing different SSI with the goal to provide important information for pedagogical decisions about curriculum and instruction. As an analytical framework, a model termed SEE-SEP covering three aspects (of knowledge, value, and experiences) and six subject areas (of sociology/culture, economy, environment/ecology, science, ethics/morality, and policy) was adopted to analyze students' justifications. A total of 208 upper secondary students (105 social science majors and 103 science majors) from Sweden were invited to justify and expound their arguments on four SSI including global warming, genetically modified organisms (GMO), nuclear power, and consumer consumption. The results showed that the social science majors generated more justifications than the science majors, the aspect of value was used most in students' argumentation regardless of students' discipline background, and justifications from the subject area of science were most often presented in nuclear power and GMO issues. We conclude by arguing that engaging teachers from different subjects to cooperate when teaching argumentation on SSI could be of great value and provide students from both social science and science programs the best possible conditions in which to develop argumentation skills.

  6. Middle School Students' Use of Epistemological Resources while Reasoning about Science Performance Tasks and Media Reports of Socioscientific Issues

    Science.gov (United States)

    Buckingham, Brandy L. E.

    The goal of science education is to prepare students to make decisions about the complicated socioscientific issues that are an inescapable part of modern life, from personal medical decisions to evaluating a political candidate's environmental platform. We cannot expect adults to maintain a deep conceptual understanding of the current state of every branch of science that might prove relevant to their lives, so we must prepare them to rely on other knowledge to make these decisions. Epistemological beliefs about scientific knowledge--what it is, its purpose, how it is constructed--are one type of knowledge that could be brought to bear when evaluating scientific claims. Complicating this situation is the fact that most adults will get most of their information about these socioscientific issues from the news media. Journalists do not have the same goals or norms as scientists, and this media lens can distort scientific issues. This dissertation addresses the question of whether we can assess epistemological change in a way that gives us meaningful information about how people will apply their epistemological understanding of science when they make decisions in the real world. First, I designed a written assessment made up of performance tasks to assess middle school students' implicit epistemological beliefs, and looked at whether we can use such an assessment to see epistemological change over two years. I then gave the same students news articles about whether there is a link between vaccines and autism and looked at their reasoning about this issue and how the journalistic features of two different articles impacted their reasoning. Finally, I examined the external validity of the epistemology assessment by looking at whether it predicted anything about students' responses to the news articles. While I was able to find evidence of differences between eighth graders' and sixth graders' use of epistemological resources within the performance tasks, I found that

  7. Preservice Science Teachers' Epistemological Beliefs and Informal Reasoning Regarding Socioscientific Issues

    Science.gov (United States)

    Ozturk, Nilay; Yilmaz-Tuzun, Ozgul

    2017-12-01

    This study investigated preservice elementary science teachers' (PSTs) informal reasoning regarding socioscientific issues (SSI), their epistemological beliefs, and the relationship between informal reasoning and epistemological beliefs. From several SSIs, nuclear power usage was selected for this study. A total of 647 Turkish PSTs enrolled in three large universities in Turkey completed the open-ended questionnaire, which assessed the participants' informal reasoning about the target SSI, and Schommer's (1990) Epistemological Questionnaire. The participants' epistemological beliefs were assessed quantitatively and their informal reasoning was assessed both qualitatively and quantitatively. The findings revealed that PSTs preferred to generate evidence-based arguments rather than intuitive-based arguments; however, they failed to generate quality evidence and present different types of evidence to support their claims. Furthermore, among the reasoning quality indicators, PSTs mostly generated supportive argument construction. Regarding the use of reasoning modes, types of risk arguments and political-oriented arguments emerged as the new reasoning modes. The study demonstrated that the PSTs had different epistemological beliefs in terms of innate ability, omniscient authority, certain knowledge, and quick learning. Correlational analyses revealed that there was a strong negative correlation between the PSTs' certain knowledge and counterargument construction, and there were negative correlations between the PSTs' innate ability, certain knowledge, and quick learning dimensions of epistemological beliefs and their total argument construction. This study has implications for both science teacher education and the practice of science education. For example, PST teacher education programs should give sufficient importance to training teachers that are skillful and knowledgeable regarding SSIs. To achieve this, specific SSI-related courses should form part of science

  8. A Framework for Guiding Future Citizens to Think Critically about Nature of Science and Socioscientific Issues

    Science.gov (United States)

    Yacoubian, Hagop A.

    2015-01-01

    In this article, I introduce a framework for guiding future citizens to think critically about nature of science (NOS) and "with" NOS as they engage in socioscientific decision making. The framework, referred to as the critical thinking--nature of science (CT-NOS) framework, explicates and targets both NOS as a learning objective and NOS…

  9. Evolution of a Model for Socio-Scientific Issue Teaching and Learning

    Science.gov (United States)

    Sadler, Troy D.; Foulk, Jaimie A.; Friedrichsen, Patricia J.

    2017-01-01

    Socio-scientific teaching and learning (SSI-TL) has been suggested as an effective approach for supporting meaningful learning in school contexts; however, limited tools exist to support the work of designing and implementing this approach. In this paper, we draw from a series of four design based research projects that have produced SSI…

  10. The Relationship of Science Knowledge, Attitude and Decision Making on Socio-Scientific Issues: The Case Study of Students' Debates on a Nuclear Power Plant in Korea

    Science.gov (United States)

    Jho, Hunkoog; Yoon, Hye-Gyoung; Kim, Mijung

    2014-01-01

    The purpose of this study was to investigate the relationship of students' understanding of science knowledge, attitude and decision making on socio-scientific issues (SSI), especially on the issues of nuclear energy in Korea. SSI-focused instructions were developed to encourage students to understand and reflect on knowledge, attitude and…

  11. Turkish preservice science teachers' socioscientific issues-based teaching practices in middle school science classrooms

    Science.gov (United States)

    Genel, Abdulkadir; Sami Topçu, Mustafa

    2016-01-01

    Background: Despite a growing body of research and curriculum reforms including socioscientific issues (SSI) across the world, how preservice science teachers (PST) or in-service science teachers can teach SSI in science classrooms needs further inquiry. Purpose: The purpose of this study is to describe the abilities of PSTs to teach SSI in middle school science classrooms, and the research question that guided the present study is: How can we characterize Turkish PSTs' SSI-based teaching practices in middle school science classrooms (ages 11-14)? Sample: In order to address the research question of this study, we explored 10 Turkish PSTs' SSI-based teaching practices in middle school science classrooms. A purposeful sampling strategy was used, thus, PSTs were specifically chosen because they were ideal candidates to teach SSI and to integrate SSI into the science curricula since they were seniors in the science education program who had to take the field experience courses. Design and method: The participants' SSI teaching practices were characterized in light of qualitative research approach. SSI-based teaching practices were analyzed, and the transcripts of all videotape recordings were coded by two researchers. Results: The current data analysis describes Turkish PSTs' SSI-based teaching practices under five main categories: media, argumentation, SSI selection and presentation, risk analysis, and moral perspective. Most of PSTs did not use media resources in their lesson and none of them considered moral perspective in their teaching. While the risk analyses were very simple and superficial, the arguments developed in the classrooms generally remained at a simple level. PSTs did not think SSI as a central topic and discussed these issues in a very limited time and at the end of the class period. Conclusions: The findings of this study manifest the need of the reforms in science education programs. The present study provides evidence that moral, media

  12. Citizenship Education and Socioscientific Issues: Implicit Concept of Citizenship in the Curriculum, Views of French Middle School Teachers

    Science.gov (United States)

    Barrue, Catherine; Albe, Virginie

    2013-05-01

    The educative goal of citizenship education through science education converges to the declared purpose of the SSI research movement. Socioscientific issues formulated in science education research covering topics as biotechnology, environmental issues, sustainable development, energy choices, have been introduced in French Middle Schools. But citizenship is often not clarified and can be multiple. After having clarified who is the citizen targeted by SSI research movement, the concept of citizen in the French curriculum needs to be clarify. What do these citizens have in common with the citizen that a sociology literature review let see oscillating between obedience and critical thinking has also been investigated. The paper also looks at the teachers' views and their contribution to citizenship education through socioscientific topics described in the national curriculum. From the analysis, different teachers' views of citizenship education have been highlighted: a normative citizenship education in connection with civility and rules and an emancipatory citizenship education to develop pupils' skills such as searching and evaluating information, argumentation and critical thinking in order to enable pupils to build their own argued opinion and to participate to public debates. This last emancipatory view of citizenship education is congruent with the aim of social empowerment within the SSI research movement.

  13. Training in Decision-making Strategies: An approach to enhance students' competence to deal with socio-scientific issues

    Science.gov (United States)

    Gresch, Helge; Hasselhorn, Marcus; Bögeholz, Susanne

    2013-10-01

    Dealing with socio-scientific issues in science classes enables students to participate productively in controversial discussions concerning ethical topics, such as sustainable development. In this respect, well-structured decision-making processes are essential for elaborate reasoning. To foster decision-making competence, a computer-based programme was developed that trains secondary school students (grades 11-13) in decision-making strategies. The main research question is: does training students to use these strategies foster decision-making competence? In addition, the influence of meta-decision aids was examined. Students conducted a task analysis to select an appropriate strategy prior to the decision-making process. Hence, the second research question is: does combining decision-making training with a task analysis enhance decision-making competence at a higher rate? To answer these questions, 386 students were tested in a pre-post-follow-up control-group design that included two training groups (decision-making strategies/decision-making strategies combined with a task analysis) and a control group (decision-making with additional ecological information instead of strategic training). An open-ended questionnaire was used to assess decision-making competence in situations related to sustainable development. The decision-making training led to a significant improvement in the post-test and the follow-up, which was administered three months after the training. Long-term effects on the quality of the students' decisions were evident for both training groups. Gains in competence when reflecting upon the decision-making processes of others were found, to a lesser extent, in the training group that received the additional meta-decision training. In conclusion, training in decision-making strategies is a promising approach to deal with socio-scientific issues related to sustainable development.

  14. Students' Positioning in the Classroom: a Study of Teacher-Student Interactions in a Socioscientific Issue Context

    Science.gov (United States)

    Bossér, Ulrika; Lindahl, Mats

    2017-07-01

    The integration of socioscientific issues (SSI) in science education calls for emphasizing dialogic classroom practices that include students' views together with multiple sources of knowledge and diverse perspectives on the issues. Such classroom practices aim to empower students to participate in decision-making on SSI. This can be accomplished by enhancing their independence as learners and positioning them as legitimate participants in societal discussions. However, this is a complex task for science teachers. In this study, we introduce positioning theory as a lens to analyse classroom discourse on SSI in order to enhance our knowledge of the manners by which teachers' interactions with students make available or promote different positions for the students, that is, different parts for the students to play as participants, when dealing with SSI in the classroom. Transcripts of interactions between one teacher and six student groups, recorded during two lessons, were analysed with respect to the positioning of the students as participants in the classroom, and in relation to the SSI under consideration. The results show that the teacher-student interactions made available contrasting student positions. The students were positioned by the teacher or positioned themselves as independent learners or as dependent on the teacher. Furthermore, the students were positioned as affected by the issue but as spectators to public negotiations of the issue. Knowledge about the manner in which teacher-student interactions can function to position students seems important for dialogic classroom practices and the promotion of student positions that sustain the pursuit of intended educational outcomes.

  15. The Effects of Emotive Reasoning on Secondary School Students' Decision-Making in the Context of Socioscientific Issues

    Science.gov (United States)

    Powell, Wardell A.

    The discrepancy between what students are being taught within K-12 science classrooms and what they experience in the real world has been well documented. This study sought to explore the ways a high school biology curriculum, which integrates socioscientific issues, impacts students' emotive reasoning and their ability to evaluate evidence, make informed decisions on contemporary scientific dilemmas, and integrate scientific content knowledge in their reasoning on SSI. Both quantitative and qualitative methods were used to examine differences within and between an SSI treatment group and a comparison group as well as individual differences among students' responses over a semester of high school biology. Results indicated students used emotions largely to evaluate evidence and make decisions on contentious scientific dilemmas. In addition, the results showed students used newly gained scientific content knowledge to make logical predictions on contentious scientific issues. Statistical significance was found between groups of students in regard to their interest in the use of embryonic stem cell treatments to restore rats' vision, as well as students' abilities to evaluate evidence. Theoretical implications regarding the use of SSI in the classroom are presented.

  16. THE EFFECT OF 5E LEARNING CYCLE INSTRUCTIONAL MODEL USING SOCIOSCIENTIFIC ISSUES (SSI LEARNING CONTEXT ON STUDENTS’ CRITICAL THINKING

    Directory of Open Access Journals (Sweden)

    A. Cahyarini

    2016-11-01

    Full Text Available The aim of this study was to investigate the effect of 5E learning cycle instructional model using socioscientific issues (SSI learning context on students’ critical thinking skills of acid-base. This study used quasi-experimental posttest only control group design. The sample consisted of three classes, which were XI MIA-4class (n = 32 that learned using 5E LC model, XI MIA-5 class (n = 33 that learned using 5E LC+SSI, and XI MIA-6 class (n = 32 that learned using conventional method. The samples were choosen by convenience sampling technique. The test instrument consisted of 15 multiple choice items which were valid and reliable (r = 0.806. The data were analyzed using one way ANOVA test and LSD posthoc test. The results of this study indicated that the students who learned using 5E LC+SSI model showed greater levels of critical thinking skills (  = 74,95 than both the student who learned using 5E LC model (  = 74,17 and  the student who learned using conventional method (  = 68,96. Based on statistics analysis, there was significant differences on students’ critical thinkings between students taught using conventional method and students taught either using 5E LC+SSI model and 5E LC model. However,  there was no significant differences on students’ critical thinking skills between students taught using 5E LC+SSI model and the students taught using 5E LC model.

  17. Students' understandings of nature of science and their arguments in the context of four socio-scientific issues

    Science.gov (United States)

    Khishfe, Rola; Alshaya, Fahad S.; BouJaoude, Saouma; Mansour, Nasser; Alrudiyan, Khalid I.

    2017-02-01

    The purpose of this study was to examine students understandings about nature of science (NOS) and their arguments in context of controversial socio-scientific issue (SSI). A total of 74 11th graders in six schools in Saudi Arabia participated in the study. The instrument used was a questionnaire consisting of four scenarios addressing SSI about global warming, genetically modified food, acid rain, and human cloning. The scenarios were followed by questions relating to argumentation and NOS. Quantitative and qualitative measures were employed to analyze the data related to participants understandings of three NOS aspects (subjective, tentative, and empirical) and their arguments components (argument, counterargument, and rebuttal). Results showed no significant correlations between argument components and the NOS aspects. On the other hand, qualitative data showed that participants who generated well-developed arguments across the four SSI also exhibited more informed understandings of the NOS aspects, especially for female participants. Further, the chi-square analyses did not show significant differences in participants arguments and NOS understandings across the four scenarios. Again, the qualitative data from questionnaires showed differences in participants responses to the different scenarios. The results were interpreted along contextual factors, emotional factors, and cultural factors. Implications for the teaching of NOS and arguments were discussed.

  18. Using the SEE-SEP Model to Analyze Upper Secondary Students' Use of Supporting Reasons in Arguing Socioscientific Issues

    Science.gov (United States)

    Christenson, Nina; Chang Rundgren, Shu-Nu; Höglund, Hans-Olof

    2012-06-01

    To achieve the goal of scientific literacy, the skills of argumentation have been emphasized in science education during the past decades. But the extent to which students can apply scientific knowledge to their argumentation is still unclear. The purpose of this study was to analyse 80 Swedish upper secondary students' informal argumentation on four socioscientific issues (SSIs) to explore students' use of supporting reasons and to what extent students used scientific knowledge in their arguments. Eighty upper secondary students were asked to express their opinions on one SSI topic they chose through written reports. The four SSIs in this study include global warming, genetically modified organisms (GMO), nuclear power, and consumption. To analyse students' supporting reasons from a holistic view, we used the SEE-SEP model, which links the six subject areas of sociology/culture (So), environment (En), economy (Ec), science (Sc), ethics/morality (Et) and policy (Po) connecting with three aspects, knowledge, value and personal experience (KVP). The results showed that students used value to a greater extent (67%) than they did scientific knowledge (27%) for all four SSI topics. According to the SEE-SEP model, the distribution of supporting reasons generated by students differed among the SSI topics. Also, some alternative concepts were disclosed in students' arguments. The implications for research and education are discussed.

  19. The correlation between concept mastery and stage of moral reasoning student using socio-scientific issues on reproductive system material

    Science.gov (United States)

    Lestari, T. A.; Saefudin; Priyandoko, D.

    2018-05-01

    This research aims to analyze the correlation between concept mastery and moral stages of students. The research method using a correlational study with stratified random sampling technique. The population in this research is all of eleventh grade students in Senior High School Bandung. Data were collected from 297 eleventh grade students of three Senior High School in Bandung with use the instrument in the form of examination and stage of moral reasoning questionnaire. The stage of moral reasoning in this research consists of two student’s moral reasoning categories based on 16 questionnaire as the indicators from Jones et al. (2007). The results of this research shows that the average of eleventh grade student’s moral reasoning stage is the advanced stage. The results of this research shows that the concept mastery and the stage of moral reasoning indicates that there are 0.370 0f a positive correlation. This research provides an overview of eleventh grade student about concept mastery and stage of moral reasoning using socio-scientific issues.

  20. Teaching Strategies for Developing Students' Argumentation Skills about Socioscientific Issues in High School Genetics

    Science.gov (United States)

    Dawson, Vaille Maree; Venville, Grady

    2010-01-01

    An outcome of science education is that young people have the understandings and skills to participate in public debate and make informed decisions about science issues that influence their lives. Toulmin's argumentation skills are emerging as an effective strategy to enhance the quality of evidence based decision making in science classrooms. In…

  1. Western Australian High School Students' Understandings about the Socioscientific Issue of Climate Change

    Science.gov (United States)

    Dawson, Vaille

    2015-01-01

    Climate change is one of the most significant science issues facing humanity; yet, teaching students about climate change is challenging: not only is it multidisciplinary, but also it is contentious and debated in political, social and media forums. Students need to be equipped with an understanding of climate change science to be able to…

  2. Debate on global warming as a socio-scientific issue: science teaching towards political literacy

    Science.gov (United States)

    dos Santos, Wildson Luiz Pereira

    2014-09-01

    The focus of this response to the original article by Tom G. H. Bryce and Stephen P. Day (Cult Stud Sci Educ. doi: 10.1007/s11422-012-9407-1, 2013) is the use of empirical data to illustrate and expand the understanding of key points of their argument. Initially, I seek to discuss possible answers to the three questions posed by the authors related to: (1) the concerns to be addressed and the scientific knowledge to be taken into account in the climate change debate, (2) the attention to be paid to perspectives taken by "alarmists" and "deniers," and (3) the approaches to be used to conduct controversial global warming debate. In this discussion, I seek to contribute to the debate proposed by the original paper, illustrating various points commented on by the authors and expanding to other possibilities, which highlight the importance of political issues in the debate. Therefore, I argue that socio-political issues must be taken into account when I aim for a scientific literacy that can enhance students' political education. Likewise, I extend the debate presented in the original article, emphasizing the attention that should be paid to these aspects and approaching science education from a critical perspective. Highlighting only the confirmation bias without considering political implications of the debate can induce a reductionist and empiricist view of science, detached from the political power that acts on scientific activity. In conclusion, I support the idea that for a critical science education, the discussion of political issues should be involved in any controversial debate, a view, which goes beyond the confirmation bias proposed by Bryce and Day for the global warming debate. These issues are indeed vital and science teachers should take them into account when preparing their lessons for the debate on climate change.

  3. Integrating Bioethics in Sciences’ curricula using values in science and socio-scientific issues

    OpenAIRE

    Sousa, C.

    2017-01-01

    [EN] The The main objective of the present work is selection of ethical issues that should be addressed with first year undergraduate and K-12 students.Since K-12 Sciences’ curriculum, in Portugal, does not include bioethics content in any discipline explicitly, teachers need to make an effort to include it. Some online materials are available to use in high school classes and will be discussed.My proposal combines inquiry learning-teaching methods with the aim of promoting the discussion of ...

  4. Socio-scientific issues with CTS focus on training of science teachers: complementary perspective

    Directory of Open Access Journals (Sweden)

    Rosa Oliveira Marins Azevedo

    2013-06-01

    Full Text Available Theoretical work that seeks to highlight the possible reasons why the STS approach has not effectively be inserted in the educational process and point out alternative to its insertion. It thus explores the origin of the STS movement and discusses its focus on education, science teaching and teacher education. It is a study in a critical perspective, from a documentary research focused on scientific production published in books, theses, papers presented in conference proceedings and journals in the field of education. The readings allowed direct the discussions, assuming the interpretative analysis for the organization of the text. The study shows that teacher education, the problems presented in its theoretical and epistemological aspects and ethical, is the main obstacle to the insertion of the STS approach in the educational process. Alternatively, points to issues of social-scientific approach to STS approach in a complementary perspective, as the possibility of improvements in the aspects highlighted

  5. The implementation of integrated science teaching materials based socio-scientific issues to improve students scientific literacy for environmental pollution theme

    Science.gov (United States)

    Yenni, Rita; Hernani, Widodo, Ari

    2017-05-01

    The study aims to determine the increasing of students' science literacy skills on content aspects and competency of science by using Integrated Science teaching materials based Socio-scientific Issues (SSI) for environmental pollution theme. The method used in the study is quasi-experiment with nonequivalent pretest and posttest control group design. The students of experimental class used teaching materials based SSI, whereas the students of control class were still using the usual textbooks. The result of this study showed a significant difference between the value of N-gain of experimental class and control class, whichalso occurred in every indicator of content aspects and competency of science. This result indicates that using of Integrated Science teaching materials based SSI can improve content aspect and competency of science and can be used as teaching materials alternative in teaching of Integrated Science.

  6. Longitudinal study of a cooperation-driven, socio-scientific issue intervention on promoting students' critical thinking and self-regulation in learning science

    Science.gov (United States)

    Wang, Hsin-Hui; Chen, Hsiang-Ting; Lin, Huann-shyang; Huang, Yu-Ning; Hong, Zuway-R.

    2017-10-01

    This longitudinal study explored the effects of a Cooperation-driven Socioscientific Issue (CDSSI) intervention on junior high school students' perceptions of critical thinking (CT) and self-regulation (SR) in Taiwan. Forty-nine grade 7 students were randomly selected as an experimental group (EG) to attend a 3-semester 72-hour intervention; while another 49 grade 7 students from the same school were randomly selected as the comparison group (CG). All participants completed a 4-wave student questionnaire to assess their perceptions of CT and SR. In addition, 8 target students from the EG with the lowest scores on either CT or SR were purposefully recruited for weekly observation. These target students and their teachers were interviewed one month after the intervention in each semester. Analyses of covariance and paired-wise t-tests revealed that the EG students' perceptions of CT and SR in learning science were improved during the study and were significantly better than their counterparts' at the end of the study. Systematic interview and classroom observation results were consistent with the quantitative findings. This study adds empirical evidence and provides insights into how CDSSI can be integrated into planning and implementing effective pedagogical strategies aimed at increasing students' perceptions of CT and SR in learning science.

  7. Controversial socio-scientific issues / Controvérsias sociocientíficas: aspectos metodológicos para a aproximação...

    Directory of Open Access Journals (Sweden)

    Ralph Levinson

    2016-07-01

    Full Text Available Entrevista com Ralph Levinson coordenada pelo Prof. Dr. Danilo Seithi Kato (UFTM. Ralph Levinson é professor do Instituto de Educação da Universidade de Londres. Ele dirige o mestrado em Educação para Ciências e orienta trabalhos de doutorado. Seus interesses de pesquisa são questões sociocientíficas controversas, ciência e justiça social, educação para ciências e criatividade e pedagogia em ciência. Ele é o autor de “Towards a theoretical framework for teaching controversial socio‐scientific issues” (2006 e de “Science education and democratic participation: an uneasy congruence” (2010. * * * Interview with Ralph Levinson coordinated by professor Danilo Seithi Kato (Federal University of Triângulo Mineiro - UFTM. Ralph Levinson is Reader in Education at the Institute of Education (University of London. He is programme director of the MA in Science Education and supervises doctoral students. His research interests are in socio-scientific issues, science and social justice, science education and creativity, and pedagogy in science. He is the author of “Towards a theoretical framework for teaching controversial socio‐scientific issues” (2006 and “Science education and democratic participation: an uneasy congruence” (2010.

  8. A case-study of a socio-scientific issues curricular and pedagogical intervention in an undergraduate microbiology course: A focus on informal reasoning

    Science.gov (United States)

    Schalk, Kelly A.

    The purpose of this investigation was to measure specific ways a student interest SSI-based curricular and pedagogical affects undergraduates' ability informally reason. The delimited components of informal reasoning measured were undergraduates' Nature of Science conceptualizations and ability to evaluate scientific information. The socio-scientific issues (SSI) theoretical framework used in this case-study has been advocated as a means for improving students' functional scientific literacy. This investigation focused on the laboratory component of an undergraduate microbiology course in spring 2008. There were 26 participants. The instruments used in this study included: (1) Individual and Group research projects, (2) journals, (3) laboratory write-ups, (4) a laboratory quiz, (5) anonymous evaluations, and (6) a pre/post article exercise. All instruments yielded qualitative data, which were coded using the qualitative software NVivo7. Data analyses were subjected to instrumental triangulation, inter-rater reliability, and member-checking. It was determined that undergraduates' epistemological knowledge of scientific discovery, processes, and justification matured in response to the intervention. Specifically, students realized: (1) differences between facts, theories, and opinions; (2) testable questions are not definitively proven; (3) there is no stepwise scientific process; and (4) lack of data weakens a claim. It was determined that this knowledge influenced participants' beliefs and ability to informally reason. For instance, students exhibited more critical evaluations of scientific information. It was also found that undergraduates' prior opinions had changed over the semester. Further, the student interest aspect of this framework engaged learners by offering participants several opportunities to influentially examine microbiology issues that affected their life. The investigation provided empirically based insights into the ways undergraduates' interest

  9. The Reasoned Arguments of a Group of Future Biotechnology Technicians on a Controversial Socio-Scientific Issue: Human Gene Therapy

    Science.gov (United States)

    Simonneaux, Laurence; Chouchane, Habib

    2011-01-01

    We tried to determine the reasoning behind the stances taken by a group of 19-21-year-old students on the controversial issue of the feasibility and acceptability of human gene therapy. The students were in training at a biotechnology institute. We organised classroom debates, punctuated by phases of epistemological "disturbances". We…

  10. A teaching-learning sequence on a socio-scientific issue: analysis and evaluation of its implementation in the classroom*

    Science.gov (United States)

    Vázquez-Alonso, Ángel; Aponte, Abdiel; Manassero-Mas, María-Antonia; Montesano, Marisa

    2016-07-01

    This study examines the effectiveness of a teaching-learning sequence (TLS) to improve the understanding of the influences and interactions between a technology (mining) and society. The aim of the study is also to show the possibility of both teaching and assessing the most innovative issues and aspects of scientific competence and their impact on the understanding of the nature of science. The methodology used a quasi-experimental, pre-post-test design with a control group, with pre-post-test differences as the empirical indicators of improved understanding. Improvements were modest, as the empirical differences (pre-post and experimental-control group) were not large, but the experimental group scored more highly than the control group. The areas that showed improvement were identified. The paper includes the TLS itself and the standardized assessment tools that are functional and transferable to other researchers and teachers. This paper first appeared in Educ. Quim (2014), 25(1), 190-202, a journal in Spanish. It appears by kind permission of the Editor, Professor Jose Chamizo. It was chosen because it illustrates the value of studies that use a standard procedure to address learning in a novel context.

  11. Student Difficulties in Socio-Scientific Argumentation and Decision-Making Research Findings: Crossing the Borders of Two Research Lines

    Science.gov (United States)

    Acar, Omer; Turkmen, Lutfullah; Roychoudhury, Anita

    2010-01-01

    Students' poor argumentation in the context of socio-scientific issues has become a concern in science education. Identified problems associated with student argumentation in socio-scientific issues are misevaluation of evidence, naive nature of science conceptualizations, and inappropriate use of value-based reasoning. In this theoretical paper,…

  12. Delusions About Evidence: On Why Scientific Evidence Should Not Be the Main Concern in Socioscientific Decision-Making

    DEFF Research Database (Denmark)

    Nielsen, Jan Alexis

    2013-01-01

    This article takes issue with the widespread assumption that students’ socioscientific decisions ought to be evidence based. On the basis of a careful conceptual analysis, it is argued that it is misleading to think in terms of evidence in socioscientific decision making because such decision mak...

  13. Secondary School Students' Understanding of Science and Their Socioscientific Reasoning

    Science.gov (United States)

    Karahan, Engin; Roehrig, Gillian

    2017-01-01

    Research in socioscientific issue (SSI)-based interventions is relatively new (Sadler in "Journal of Research in Science Teaching" 41:513-536, 2004; Zeidler et al. in "Journal of Research in Science Teaching" 46:74-101, 2009), and there is a need for understanding more about the effects of SSI-based learning environments…

  14. Photovoice: A Community-Based Socioscientific Pedagogical Tool

    Science.gov (United States)

    Cook, Kristin; Buck, Gayle

    2010-01-01

    Situating instruction in a local context, socioscientific issues (SSIs) offers students an opportunity to become active participants in the community and has the potential to encourage them to authentically and critically participate and engage in understanding, caring for, and transforming the world to which they belong. Photovoice is one way…

  15. Toward socio-scientific participation: changing culture in the science classroom and much more. Setting the stage

    Science.gov (United States)

    Taylor, Peter; Lee, Stuart H.; Tal, Tali

    2006-12-01

    In response to Tali and Yarden's presentation of their efforts to teach socioscientific issues, the discussants address issues of authentic versus simulated activities; teachers as learners or co-creators with their students; educating people to contribute to science-based decisionmaking; the development of such socioscientific competence; the relationship between group or participatory processes and individual development; framing real world cases for every age of student; making space to delve into the historical and social background to any scientific theory, practice, or application; educating teachers who can coach students in socioscientific inquiry; and facing off against the traditional and resurgent emphasis on highstakes, content-oriented testing of students in science.

  16. Students' socio-scientific reasoning on controversies from the viewpoint of education for sustainable development

    Science.gov (United States)

    Simonneaux, Laurence; Simonneaux, Jean

    2009-09-01

    In this article, we study third-year university students' reasoning about three controversial socio-scientific issues from the viewpoint of education for sustainable development: local issues (the reintroduction of bears in the Pyrenees in France, wolves in the Mercantour) and a global one (global warming). We used the theoretical frameworks of social representations and of socio-scientific reasoning. Students' reasoning varies according to the issues, in particular because of their emotional proximity with the issues and their socio-cultural origin. About this kind of issues, it seems pertinent to integrate into the operations of socio-scientific reasoning not only the consideration of values, but also the analysis of the modes of governance and the place given to politics.

  17. Searching for Scientific Literacy and Critical Pedagogy in Socioscientific Curricula: A Critical Discourse Analysis

    Science.gov (United States)

    Cummings, Kristina M.

    2017-01-01

    The omnipresence of science and technology in our society require the development of a critical and scientifically literate citizenry. However, the inclusion of socioscientific issues, which are open-ended controversial issues informed by both science and societal factors such as politics, economics, and ethics, do not guarantee the development of…

  18. Secondary School Students' Understanding of Science and Their Socioscientific Reasoning

    Science.gov (United States)

    Karahan, Engin; Roehrig, Gillian

    2017-08-01

    Research in socioscientific issue (SSI)-based interventions is relatively new (Sadler in Journal of Research in Science Teaching 41:513-536, 2004; Zeidler et al. in Journal of Research in Science Teaching 46:74-101, 2009), and there is a need for understanding more about the effects of SSI-based learning environments (Sadler in Journal of Research in Science Teaching 41:513-536, 2004). Lee and Witz (International Journal of Science Education 31:931-960, 2009) highlighted the need for detailed case studies that would focus on how students respond to teachers' practices of teaching SSI. This study presents case studies that investigated the development of secondary school students' science understanding and their socioscientific reasoning within SSI-based learning environments. A multiple case study with embedded units of analysis was implemented for this research because of the contextual differences for each case. The findings of the study revealed that students' understanding of science, including scientific method, social and cultural influences on science, and scientific bias, was strongly influenced by their experiences in SSI-based learning environments. Furthermore, multidimensional SSI-based science classes resulted in students having multiple reasoning modes, such as ethical and economic reasoning, compared to data-driven SSI-based science classes. In addition to portraying how participants presented complexity, perspectives, inquiry, and skepticism as aspects of socioscientific reasoning (Sadler et al. in Research in Science Education 37:371-391, 2007), this study proposes the inclusion of three additional aspects for the socioscientific reasoning theoretical construct: (1) identification of social domains affecting the SSI, (2) using cost and benefit analysis for evaluation of claims, and (3) understanding that SSIs and scientific studies around them are context-bound.

  19. Beyond Evidence: A Critical Appraisal of Global Warming as a Socio-Scientific Issue and a Reflection on the Changing Nature of Scientific Literacy in School

    Science.gov (United States)

    Colucci-Gray, L.

    2014-01-01

    Tom G. K. Bryce and Stephen P. Day's (2013) original article on scepticism and doubt in science education explores the context of citizens' attitudes towards the complexities and uncertainties of global issues, namely global warming. This response aims to stimulate reflection on some of the implicit assumptions underpinning the…

  20. Beyond evidence: a critical appraisal of global warming as a socio-scientific issue and a reflection on the changing nature of scientific literacy in school

    Science.gov (United States)

    Colucci-Gray, L.

    2014-09-01

    Tom G. K. Bryce and Stephen P. Day's (2013) original article on scepticism and doubt in science education explores the context of citizens' attitudes towards the complexities and uncertainties of global issues, namely global warming. This response aims to stimulate reflection on some of the implicit assumptions underpinning the relationships between science, technology and the public. I argue that an underestimation of the political and ethical dimensions of science and technology limits the possibilities for education to set the agenda for citizens' participation in science and technological matters. Drawing on Sheila Jasanoff's model of co-production, this paper proposes a radical re-affirmation of the aims and purposes of science education to embrace a multiplicity of disciplines, narratives and ways of knowing in science, technology and society issues.

  1. Evaluation of Student Models on Current Socio-Scientific Topics Based on System Dynamics

    Science.gov (United States)

    Nuhoglu, Hasret

    2014-01-01

    This study aims to 1) enable primary school students to develop models that will help them understand and analyze a system, through a learning process based on system dynamics approach, 2) examine and evaluate students' models related to socio-scientific issues using certain criteria. The research method used is a case study. The study sample…

  2. Socio-scientific controversies and beginning teachers’ pedagogical practice

    Directory of Open Access Journals (Sweden)

    Pedro Reis

    2005-08-01

    Full Text Available The current investigation aimed to study the impact of recent socio-scientific controversies, made public through the media, on the concepts and practices of a group of Natural Science teachers at the start of their careers. This study is particularly relevant at a time that is heavily marked by much debate regarding the social and environmental impact of several scientific and technological innovations and by the implementation of new science curricula, that stress the importance of discussing socio-scientific controversies in the context of students’ scientific alphabetisation (namely in their understanding of the nature of science and its relation to society and culture (McComas, 2000. This investigation followed an interpretative approach of a qualitative nature. Through the construction of case studies, it sought to analyse the possible impact of socio-scientific controversies on the teachers’ concepts (about the nature, teaching and learning of science and pedagogic practice. For data collection semi-structured interviews were conducted and classes observed.The controversial issues raised by certain recent technological innovations – namely the environmental, social and cultural impact they may have – did have an impact on the teachers’ concepts about the nature, teaching and learning of science. Besides reinforcing the duality of feelings as regards science and technology, as a source of both progress and concern, they triggered in these teachers the idea of the need for a widespread scientific alphabetisation that empowers the population for understanding and deciding and acting upon these issues. However, the concept of scientific alphabetisation and the best way to achieve it vary among the teachers participating in this study.

  3. Searching for scientific literacy and critical pedagogy in socioscientific curricula: A critical discourse analysis

    Science.gov (United States)

    Cummings, Kristina M.

    The omnipresence of science and technology in our society require the development of a critical and scientifically literate citizenry. However, the inclusion of socioscientific issues, which are open-ended controversial issues informed by both science and societal factors such as politics, economics, and ethics, do not guarantee the development of these skills. The purpose of this critical discourse analysis is to identify and analyze the discursive strategies used in intermediate science texts and curricula that address socioscientific topics and the extent to which the discourses are designed to promote or suppress the development of scientific literacy and a critical pedagogy. Three curricula that address the issue of energy and climate change were analyzed using Gee's (2011) building tasks and inquiry tools. The curricula were written by an education organization entitled PreSEES, a corporate-sponsored group called NEED, and a non-profit organization named Oxfam. The analysis found that the PreSEES and Oxfam curricula elevated the significance of climate change and the NEED curriculum deemphasized the issue. The PreSEES and Oxfam curricula promoted the development of scientific literacy while the NEED curricula suppressed its development. The PreSEES and Oxfam curricula both promoted the development of the critical pedagogy; however, only the Oxfam curricula provided authentic opportunities to enact sociopolitical change. The NEED curricula suppressed the development of critical pedagogy. From these findings, the following conclusions were drawn. When socioscientific issues are presented with the development of scientific literacy and critical pedagogy, the curricula allow students to develop fact-based opinions about the issue. However, curricula that address socioscientific issues without the inclusion of these skills minimize the significance of the issue and normalize the hegemonic worldview promoted by the curricula's authors. Based on these findings

  4. Navigating the Complexity of Socio-scientific Controversies—How Students Make Multiple Voices Present in Discourse

    Science.gov (United States)

    Solli, Anne; Hillman, Thomas; Mäkitalo, Åsa

    2017-10-01

    In this article, we argue that students' unfolding discourse on socio-scientific issues (SSI) can be fruitfully analyzed by using dialogical theories of language and communication (Bakhtin 1986; Linell 2009). While research in science education often reports on how individual reasoning changes when bringing SSI into the classroom, we argue for the relevance of analyzing how the individual is "in dialogue" with present as well as remote interlocutors and contexts on the internet. We suggest that the analytical approach is particularly sensitized to illuminate how students' handle multiple perspectives. A dialogical perspective takes as its premise that SSI are part of society, where politicians, interest groups, and scientists engage in debates and offer perspectives that are often in conflict. Rather than assuming that the individual student is the primary unit for analysis, a dialogical approach is premised on an analysis that incorporates several perspectives and voices—a multivocality that also resides with the individual. Arguing for the relevance of this analytical approach to studies of SSI in the classroom, we analyze a group of students in upper secondary school as they discuss hydraulic fracturing after having worked with online data. The results illuminate how students discursively manage multivocality and multimodality inherent in the following SSI online. We describe a set of discursive means that the students use to handle the many perspectives involved when communicating about the issue. In addition, we describe and articulate what kind of communicative competences that are involved and, hence, could be cultivated through education, when engaging in public debates.

  5. Inherently safe reactors

    International Nuclear Information System (INIS)

    Maartensson, Anders

    1992-01-01

    A rethinking of nuclear reactor safety has created proposals for new designs based on inherent and passive safety principles. Diverging interpretations of these concepts can be found. This article reviews the key features of proposed advanced power reactors. An evaluation is made of the degree of inherent safety for four different designs: the AP-600, the PIUS, the MHTGR and the PRISM. The inherent hazards of today's most common reactor principles are used as reference for the evaluation. It is concluded that claims for the new designs being inherently, naturally or passively safe are not substantiated by experience. (author)

  6. Using Our Heads and HARTSS*: Developing Perspective-Taking Skills for Socioscientific Reasoning (*Humanities, ARTS, and Social Sciences)

    Science.gov (United States)

    Kahn, Sami; Zeidler, Dana L.

    2016-01-01

    Functional scientific literacy demands an informed citizenry capable of negotiating controversial socioscientific issues (SSI). Perspective taking is critical to SSI implementation as it enables understanding of the diverse cognitive and emotional perspectives of others. Science teacher educators must therefore facilitate teachers' promotion of…

  7. Discussing agrochemical themes: an approach through socio-scientific controversies

    Directory of Open Access Journals (Sweden)

    Eril Medeiros da Fonseca

    2017-12-01

    Full Text Available The theme of "agro-toxicology" in the Rural Education pervades key issues to be problematized, such as the care of rural workers, from the concept of health as something broad, involving access to cultural goods, leisure and communication and still, the collective physical, mental and social well-being. The use of pesticides, in addition to compromising the health of those who work in the field and those who feed on what is produced in the field, brings with it a conception of health that, in addition to suffering and individualizing, affects our biological diversity. The objective of this study is to discuss pesticides and their implications for health, through the approach of Socio-Scientific Controversies (CSC in Science Teaching and Rural Education.

  8. Socioscientific Argumentation: The effects of content knowledge and morality

    Science.gov (United States)

    Sadler, Troy D.; Donnelly, Lisa A.

    2006-10-01

    Broad support exists within the science education community for the incorporation of socioscientific issues (SSI) and argumentation in the science curriculum. This study investigates how content knowledge and morality contribute to the quality of SSI argumentation among high school students. We employed a mixed-methods approach: 56 participants completed tests of content knowledge and moral reasoning as well as interviews, related to SSI topics, which were scored based on a rubric for argumentation quality. Multiple regression analyses revealed no statistically significant relationships among content knowledge, moral reasoning, and argumentation quality. Qualitative analyses of the interview transcripts supported the quantitative results in that participants very infrequently revealed patterns of content knowledge application. However, most of the participants did perceive the SSI as moral problems. We propose a “Threshold Model of Knowledge Transfer” to account for the relationship between content knowledge and argumentation quality. Implications for science education are discussed.

  9. Raciocínio moral na tomada de decisões em relação a questões sociocientíficas: o exemplo do melhoramento genético humano Moral reasoning in decision-making regarding socioscientific issues: the human genetic improvement example

    Directory of Open Access Journals (Sweden)

    Márcio Andrei Guimarães

    2010-01-01

    Full Text Available Nos últimos anos, os avanços nas Ciências Biológicas têm levado a sociedade a discutir diversas questões no campo da moral e da ética. Questões como engenharia genética, clonagem e pesquisas com células-tronco são questões chamadas de sociocientíficas por estarem na interface entre a ciência e a sociedade. Nesse trabalho buscamos entender como estudantes de Ensino Médio percebem e interpretam questões relacionadas à manipulação genética em seres humanos. Houve divisão de opiniões em relação à eugenia negativa, que se destina a remover características desfavoráveis das pessoas; mas a eugenia positiva, que busca melhoramento de características estéticas, foi rejeitada por todos os estudantes. As variações nas opiniões em relação ao assunto tratado podem ser, em grande medida, devidas às representações sociais dos estudantes.In the recent years the advances in biological sciences has been convincing society to discuss issues concerning moral and ethics. Issues as cloning, stem-cell research and genetic engineering are called socioscientific issues because they put into evidence the interface between science and society. In this paper we aimed at understanding how High School students realize and interpret issues regarding human genetic improvement. As a result we have found divergent opinions regarding negative eugenics, specifically about its attempts of taking out undesirable characteristics of individuals; but there was an agreement among all the students in rejecting positive eugenics, that aims at improving individuals esthetical characteristics. The divergences and differences of opinions may be related to the students' social representations.

  10. Operation: Inherent Resolve

    DEFF Research Database (Denmark)

    Cramer-Larsen, Lars

    2015-01-01

    Kapitlet giver læseren indsigt i den internationale koalitions engagement mod IS igennem Operaton Inherent Resolve; herunder koalitionens strategi i forhold til IS strategi, ligesom det belyser kampagnens legalitet og folkeretlige grundlag, ligesom det giver et bud på overvejelser om kampagnens...

  11. Vowel Inherent Spectral Change

    CERN Document Server

    Assmann, Peter

    2013-01-01

    It has been traditional in phonetic research to characterize monophthongs using a set of static formant frequencies, i.e., formant frequencies taken from a single time-point in the vowel or averaged over the time-course of the vowel. However, over the last twenty years a growing body of research has demonstrated that, at least for a number of dialects of North American English, vowels which are traditionally described as monophthongs often have substantial spectral change. Vowel Inherent Spectral Change has been observed in speakers’ productions, and has also been found to have a substantial effect on listeners’ perception. In terms of acoustics, the traditional categorical distinction between monophthongs and diphthongs can be replaced by a gradient description of dynamic spectral patterns. This book includes chapters addressing various aspects of vowel inherent spectral change (VISC), including theoretical and experimental studies of the perceptually relevant aspects of VISC, the relationship between ar...

  12. Policy issues inherent in advanced technology development

    Energy Technology Data Exchange (ETDEWEB)

    Baumann, P.D.

    1994-12-31

    In the development of advanced technologies, there are several forces which are involved in the success of the development of those technologies. In the overall development of new technologies, a sufficient number of these forces must be present and working in order to have a successful opportunity at developing, introducing and integrating into the marketplace a new technology. This paper discusses some of these forces and how they enter into the equation for success in advanced technology research, development, demonstration, commercialization and deployment. This paper limits itself to programs which are generally governmental funded, which in essence represent most of the technology development efforts that provide defense, energy and environmental technological products. Along with the identification of these forces are some suggestions as to how changes may be brought about to better ensure success in a long term to attempt to minimize time and financial losses.

  13. Policy issues inherent in advanced technology development

    International Nuclear Information System (INIS)

    Baumann, P.D.

    1994-01-01

    In the development of advanced technologies, there are several forces which are involved in the success of the development of those technologies. In the overall development of new technologies, a sufficient number of these forces must be present and working in order to have a successful opportunity at developing, introducing and integrating into the marketplace a new technology. This paper discusses some of these forces and how they enter into the equation for success in advanced technology research, development, demonstration, commercialization and deployment. This paper limits itself to programs which are generally governmental funded, which in essence represent most of the technology development efforts that provide defense, energy and environmental technological products. Along with the identification of these forces are some suggestions as to how changes may be brought about to better ensure success in a long term to attempt to minimize time and financial losses

  14. Inherently safe characteristics of nuclear reactors

    International Nuclear Information System (INIS)

    1989-01-01

    This report is based on a detailed study which was carried out by Colenco (a company of the Motor-Columbus Group) on behalf of the Commission of the European Communities (CEC). It presents a summary of this study and concentrates more on the generic issues involved in the subject of inherent safety in nuclear power plants. It is assumed that the reader is reasonably familiar with the design outline of the systems included in the report. The report examines the role of inherent design features in achieving the safety of nuclear power plants as an alternative to the practice, which is largely followed in current reactors, of achieving safety by the addition of engineered safety features. The report examines current reactor systems to identify the extent to which their characteristics are either already inherently safe or, on the other hand, have inherent characteristics that require protective action to be taken. It then considers the advantages of introducing design changes to improve their inherent safety characteristics. Next, it looks at some new reactor types for which claims of inherent safety are made to see to what extent these claims are justified. The general question is then considered whether adoption of the inherently safe reactors would give advantages (by reducing risk in real terms or by improving the public acceptability of nuclear power) which are sufficient to offset the expected high costs and the technical risks associated with any new technology

  15. Socioscientific Argumentation of Pre-Service Teachers about Genetically Modified Organisms

    Science.gov (United States)

    Herawati, D.; Ardianto, D.

    2017-09-01

    This study aims to investigate socioscientific argumentation of pre-service teachers of science and non-science major regarding Genetically Modified Organisms (GMOs) issue. We used descriptive study and involved second-year pre-service teachers from two major, 28 pre-service science teachers (PSTs) and 28 pre-service non-science teachers (PNSTs) as participants. Paper and pencil test was administered in order to obtain the data of PSTs’ and PNSTs’ argument about GMOs. All of the data were analyzed by descriptive analysis. We applied Toulmin Argumentation Pattern (TAP) as a basic framework to identify the argumentation component. The result showed that both PSTs and PNSTs were able to propose an argument with a claim, data, and/or warrant.. Most of their argument contain data which provided in the text, without any further reasoning or relevant scientific knowledge. So, the coherency between argumentation component in both PSTs and PNSTs was limited. However, PSTs are more able to propose coherent arguments than PNSTs. These findings indicated that educational background and learning experiences may influence to pre-service teacher argumentation in the context of GMOs. Beside that, teaching and learning process which focused on the socioscientific issues is necessary to develop pre-service teachers’ argumentation

  16. Supporting Students' Learning and Socioscientific Reasoning About Climate Change—the Effect of Computer-Based Concept Mapping Scaffolds

    Science.gov (United States)

    Eggert, Sabina; Nitsch, Anne; Boone, William J.; Nückles, Matthias; Bögeholz, Susanne

    2017-02-01

    Climate change is one of the most challenging problems facing today's global society (e.g., IPCC 2013). While climate change is a widely covered topic in the media, and abundant information is made available through the internet, the causes and consequences of climate change in its full complexity are difficult for individuals, especially non-scientists, to grasp. Science education is a field which can play a crucial role in fostering meaningful education of students to become climate literate citizens (e.g., NOAA 2009; Schreiner et al., 41, 3-50, 2005). If students are, at some point, to participate in societal discussions about the sustainable development of our planet, their learning with respect to such issues needs to be supported. This includes the ability to think critically, to cope with complex scientific evidence, which is often subject to ongoing inquiry, and to reach informed decisions on the basis of factual information as well as values-based considerations. The study presented in this paper focused on efforts to advance students in (1) their conceptual understanding about climate change and (2) their socioscientific reasoning and decision making regarding socioscientific issues in general. Although there is evidence that "knowledge" does not guarantee pro-environmental behavior (e.g. Schreiner et al., 41, 3-50, 2005; Skamp et al., 97(2), 191-217, 2013), conceptual, interdisciplinary understanding of climate change is an important prerequisite to change individuals' attitudes towards climate change and thus to eventually foster climate literate citizens (e.g., Clark et al. 2013). In order to foster conceptual understanding and socioscientific reasoning, a computer-based learning environment with an embedded concept mapping tool was utilized to support senior high school students' learning about climate change and possible solution strategies. The evaluation of the effect of different concept mapping scaffolds focused on the quality of student

  17. Patterns of informal reasoning in the context of socioscientific decision making

    Science.gov (United States)

    Sadler, Troy D.; Zeidler, Dana L.

    2005-01-01

    The purpose of this study is to contribute to a theoretical knowledge base through research by examining factors salient to science education reform and practice in the context of socioscientific issues. The study explores how individuals negotiate and resolve genetic engineering dilemmas. A qualitative approach was used to examine patterns of informal reasoning and the role of morality in these processes. Thirty college students participated individually in two semistructured interviews designed to explore their informal reasoning in response to six genetic engineering scenarios. Students demonstrated evidence of rationalistic, emotive, and intuitive forms of informal reasoning. Rationalistic informal reasoning described reason-based considerations; emotive informal reasoning described care-based considerations; and intuitive reasoning described considerations based on immediate reactions to the context of a scenario. Participants frequently relied on combinations of these reasoning patterns as they worked to resolve individual socioscientific scenarios. Most of the participants appreciated at least some of the moral implications of their decisions, and these considerations were typically interwoven within an overall pattern of informal reasoning. These results highlight the need to ensure that science classrooms are environments in which intuition and emotion in addition to reason are valued. Implications and recommendations for future research are discussed.

  18. Inherently safe light water reactors

    International Nuclear Information System (INIS)

    Ise, Takeharu

    1987-01-01

    Today's large nuclear power reactors of world-wise use have been designed based on the philosophy. It seems that recent less electricity demand rates, higher capital cost and the TMI accident let us acknowledge relative small and simplified nuclear plants with safer features, and that Chernobyl accident in 1983 underlines the needs of intrinsic and passive safety characteristics. In such background, several inherently safe reactor concepts have been presented abroad and domestically. First describing 'Can inherently safe reactors be designed,' then I introduce representative reactor concepts of inherently safe LWRs advocated abroad so far. All of these innovative reactors employ intrinsic and passive features in their design, as follows: (1) PIUS, an acronym for Process Inherent Ultimate Safety, or an integral PWR with passive heat sink and passive shutdown mechanism, advocated by ASEA-ATOM of Sweden. (2) MAP(Minimum Attention Plant), or a self-pressurized, natural circulation integral PWR, promoted by CE Inc. of the U.S. (3) TPS(TRIGA Power System), or a compact PWR with passive heat sink and inherent fuel characteristics of large prompt temperature coefficient, prompted by GA Technologies Inc. of the U.S. (4) PIUS-BWR, or an inherently safe BWR employing passively actuated fluid valves, in competition with PIUS, prompted by ORNL of the U.S. Then, I will describe the domestic trends in Japan and the innovative inherently safe LWRs presented domestically so far. (author)

  19. A Conceptual Analysis of Perspective Taking in Support of Socioscientific Reasoning

    Science.gov (United States)

    Kahn, Sami

    Scientific literacy is concerned with the informed citizens' ability to negotiate scientifically-related societal issues. The suite of skills necessary to negotiate these complex issues is referred to as Socioscientific Reasoning (SSR). SSR requires, among other things, perspective-taking abilities in order to consider the multi-faceted nature of these open-ended, debatable socioscientific issues (SSI). Developing interventions and instruments to foster and measure perspective taking in support of SSR is therefore critical to the promotion of functional scientific literacy through both research and practice. Although widely studied in many disciplines, perspective taking is a particularly tangled construct that has been used to describe a range of activities representing different psychological domains and applied interchangeably with related constructs such as role taking, empathy, and theory of mind. This ambiguity makes it difficult to ensure construct validity and prevents science education researchers from honing in on the precise skills they wish to study and promote. To clarify the construct of perspective taking, this study undertook a conceptual analysis to operationalize perspective taking, drawing comparisons and distinctions between it and related constructs. Further, by applying a method known as conception development, perspective taking was positioned in the context of SSR, particularly as it relates to moral development, in order to devise a more precise construct relating perspective taking to SSR called socioscientific perspective taking (SSPT). It is asserted that SSPT requires engagement with others or their circumstances, an etic/emic shift, and a moral context comprised of reflective and reflexive judgment. Finally, in order to identify promising interventions for promoting SSPT in the science classroom, the newly-developed SSPT construct was applied to a series of extensively researched curricular frameworks that promote perspective taking in

  20. Intertextuality for Handling Complex Environmental Issues

    Science.gov (United States)

    Byhring, Anne Kristine; Knain, Erik

    2016-01-01

    Nowhere is the need for handling complexity more pertinent than in addressing environmental issues. Our study explores students' situated constructs of complexity in unfolding discourses on socio-scientific issues. Students' dialogues in two group-work episodes are analysed in detail, with tools from Systemic Functional Linguistics. We identify…

  1. Prospects for inherently safe reactors

    International Nuclear Information System (INIS)

    Barkenbus, J.N.

    1988-01-01

    Public fears over nuclear safety have led some within the nuclear community to investigate the possibility of producing inherently safe nuclear reactors; that is, reactors that are transparently incapable of producing a core melt. While several promising designs of such reactors have been produced, support for large-scale research and development efforts has not been forthcoming. The prospects for commercialization of inherently safe reactors, therefore, are problematic; possible events such as further nuclear reactor accidents and superpower summits, could alter the present situation significantly. (author)

  2. Fusion blanket inherent safety assessment

    International Nuclear Information System (INIS)

    Sze, D.K.; Jung, J.; Cheng, E.T.

    1986-01-01

    Fusion has significant potential safety advantages. There is a strong incentive for designing fusion plants to ensure that inherent safety will be achieved. Accordingly, both the Tokamak Power Systems Studies and MINIMARS have identified inherent safety as a design goal. A necessary condition is for the blanket to maintain its configuration and integrity under all credible accident conditions. A main problem is caused by afterheat removal in an accident condition. In this regard, it is highly desirable to achieve the required level of protection of the plant capital investment and limitation of radioactivity release by systems that rely only on inherent properties of matter (e.g., thermal conductivity, specific heat, etc.) and without the use of active safety equipment. This paper assesses the conditions under which inherent safety is feasible. Three types of accident conditions are evaluated for two blankets. The blankets evaluated are a self cooled vanadium/lithium blanket and a self-cooled vanadium/Flibe blanket. The accident conditions evaluated are: (1) loss-of-flow accident; (2) loss-of-coolant accident (LOCA); and (3) partial loss-of-coolant accident

  3. The representation of inherent properties.

    Science.gov (United States)

    Prasada, Sandeep

    2014-10-01

    Research on the representation of generic knowledge suggests that inherent properties can have either a principled or a causal connection to a kind. The type of connection determines whether the outcome of the storytelling process will include intuitions of inevitability and a normative dimension and whether it will ground causal explanations.

  4. The Coastal Zone: Man and Nature. An Application of the Socio-Scientific Reasoning Model.

    Science.gov (United States)

    Maul, June Paradise; And Others

    The curriculum model described here has been designed by incorporating the socio-scientific reasoning model with a simulation design in an attempt to have students investigate the onshore impacts of Outer Continental Shelf (OCS) gas and oil development. The socio-scientific reasoning model incorporates a logical/physical reasoning component as…

  5. Investigation on the Inclusion of Socio-Scientific Acquisitions in Curriculum of Science and Technology Lesson

    Science.gov (United States)

    Guler, Mutlu Pinar Demirci

    2013-01-01

    According to its definition, socio-scientific subjects emerge during scientific and technologic developments. Besides information, attitude and value constraints are effective in decision-making processes and thus there is no consensus on socio-scientific subjects yet and it leads to social discussions. These subjects comprise decision making…

  6. Approaches to achieving inherently safe fusion power plants

    International Nuclear Information System (INIS)

    Piet, S.J.

    1986-01-01

    Achieving inherently safe fusion facilities and conceptual designs is a challenge to the fusion community. Success should provide fusion with important competitive advantages versus other energy technologies. Inherent safety should mean a facility designed with passive safety features such that the public is protected from any acute fatalities under all credible accidental circumstances. A key aspect to inherent safety is demonstrability - the ability to prove that a deign is as safe as claimed. Three complementary approaches to achieving inherent safety are examined: toxin inventory reduction, energy source reduction and design fault tolerance. Four levels of assurance are defined, associated with uncertainty in the words ''credible' and ''demonstrable.'' Sound reasons exist for believing that inherent safety puts a modest upper bound on all accident consequences; it should be considered a part of the collection of safety and environmental issues, which also include lower consequence accidents, waste management, and effluent control

  7. MHTGR inherent heat transfer capability

    International Nuclear Information System (INIS)

    Berkoe, J.M.

    1992-01-01

    This paper reports on the Commercial Modular High Temperature Gas-Cooled Reactor (MHTGR) which achieves improved reactor safety performance and reliability by utilizing a completely passive natural convection cooling system called the RCCS to remove decay heat in the event that all active cooling systems fail to operate. For the highly improbable condition that the RCCS were to become non-functional following a reactor depressurization event, the plant would be forced to rely upon its inherent thermo-physical characteristics to reject decay heat to the surrounding earth and ambient environment. A computational heat transfer model was created to simulate such a scenario. Plant component temperature histories were computed over a period of 20 days into the event. The results clearly demonstrate the capability of the MHTGR to maintain core integrity and provide substantial lead time for taking corrective measures

  8. Inherent/passive safety for fusion

    International Nuclear Information System (INIS)

    Piet, S.J.

    1986-06-01

    The concept of inherent or passive passive safety for fusion energy is explored, defined, and partially quantified. Four levels of safety assurance are defined, which range from true inherent safety to passive safety to protection via active engineered safeguard systems. Fusion has the clear potential for achieving inherent or passive safety, which should be an objective of fusion research and design. Proper material choice might lead to both inherent safety and high mass power density, improving both safety and economics. When inherent safety is accomplished, fusion will be well on the way to achieving its ultimate potential and to be truly different and superior

  9. Incorporation of Socio-scientific Content into Active Learning Activities

    Science.gov (United States)

    King, D. B.; Lewis, J. E.; Anderson, K.; Latch, D.; Sutheimer, S.; Webster, G.; Moog, R.

    2014-12-01

    Active learning has gained increasing support as an effective pedagogical technique to improve student learning. One way to promote active learning in the classroom is the use of in-class activities in place of lecturing. As part of an NSF-funded project, a set of in-class activities have been created that use climate change topics to teach chemistry content. These activities use the Process Oriented Guided Inquiry Learning (POGIL) methodology. In this pedagogical approach a set of models and a series of critical thinking questions are used to guide students through the introduction to or application of course content. Students complete the activities in their groups, with the faculty member as a facilitator of learning. Through assigned group roles and intentionally designed activity structure, process skills, such as teamwork, communication, and information processing, are developed during completion of the activity. Each of these climate change activities contains a socio-scientific component, e.g., social, ethical and economic data. In one activity, greenhouse gases are used to explain the concept of dipole moment. Data about natural and anthropogenic production rates, global warming potential and atmospheric lifetimes for a list of greenhouse gases are presented. The students are asked to identify which greenhouse gas they would regulate, with a corresponding explanation for their choice. They are also asked to identify the disadvantages of regulating the gas they chose in the previous question. In another activity, where carbon sequestration is used to demonstrate the utility of a phase diagram, students use economic and environmental data to choose the best location for sequestration. Too often discussions about climate change (both in and outside the classroom) consist of purely emotional responses. These activities force students to use data to support their arguments and hypothesize about what other data could be used in the corresponding discussion to

  10. Analysis of student’s scientific literacy skills through socioscientific issue’s test on biodiversity topics

    Science.gov (United States)

    Purwani, L. D.; Sudargo, F.; Surakusumah, W.

    2018-05-01

    The aim of this study was to describe student’s scientific literacy skills on biodiversity topics at grade X of senior high school. Dimension of scientific literacy that was asses is science’s competence and attitude towards science. The science competency tests and attitude rating scale based on biodiversity’s socio-scientific issue is used to measure scientific literacy skills. The result of study showed that student’s scientific literacy skills for science competence dimension are low (15.84% for class A and 19.50% for class B) and also for attitude toward science dimension (31.15% for class A and 37.05%). We concluded that student’s scientific literacy skills are low (23.49% and 28.55%).

  11. The Citizens' Exhibition: A Combination of Socio-scientific, Participative and Artistic Elements

    Directory of Open Access Journals (Sweden)

    Birgit Böhm

    2008-05-01

    Full Text Available Through its incorporation of socio-scientific, participative and artistic elements, the "Citizens' Exhibition" is an example of how applied performative social science can be implemented. The method was created by teaching qualitative methods and community psychology approaches in courses for students of psychology in the 1990's. The Citizens' Exhibition combines qualitative methods, such as interview and text interpretation, with artistic-aesthetic methods, such as photography and film, to form an integrated concept. In the tradition of action research, the practice is applied in the exploration of societal issues. The Citizens' Exhibition supports dialogue and furthering communication processes between the stakeholders through the presentation of diverse perspectives. In this regard, the staging of the exhibition opening has a particular importance. The following article about the Citizens' Exhibition presents the practice's origin and history in the first section and, in the second section, offers an introduction to the individual methodological steps. In the third section, various Citizens' Exhibitions are described as illustrations of the method. The last section discusses the vision of the Citizens' Exhibition, its performative component, strengths and limitations, considers the results of an existing evaluation study and looks at the future uses of the practice. Particular regard should be paid here to a combination of methods that enable a long-term participation effect, the expansion of participatory possibilities for the research subjects, and experimentation with additional artistic methods. URN: urn:nbn:de:0114-fqs0802337

  12. Effect of Religious Belief on Informal Reasoning about Biotechnology Issues

    Science.gov (United States)

    Pope, Timothy; Dawson, Vaille; Koul, Rekha

    2017-01-01

    The advances of modern biotechnology provide teachers with a number of opportunities to explore socioscientific issues, and in doing so to enhance students' reasoning skills. Although some attempt has been made to understand cultural differences in students' informal reasoning across international and regional boundaries, there is limited research…

  13. Can the inherence heuristic explain vitalistic reasoning?

    Science.gov (United States)

    Bastian, Brock

    2014-10-01

    Inherence is an important component of psychological essentialism. By drawing on vitalism as a way in which to explain this link, however, the authors appear to conflate causal explanations based on fixed features with those based on general causal forces. The disjuncture between these two types of explanatory principles highlights potential new avenues for the inherence heuristic.

  14. Inherent safety, ethics and human error.

    Science.gov (United States)

    Papadaki, Maria

    2008-02-11

    stated. The reason this article is presented here is that I believe that often, complex accidents, similarly to insignificant ones, often demonstrate an attitude which can be characterized as "inherently unsafe". I take the view that the enormous human potential and the human ability to minimize accidents needs to become a focal point towards inherent safety. Restricting ourselves to human limitations and how we could "treat" or prevent humans from not making accidents needs to be re-addressed. The purpose of this presentation is to highlight observations and provoke a discussion on how we could possibly improve the understanding of safety related issues. I do not intent to reject or criticize existing methodologies. (The entire presentation is strongly influenced by Trevor Kletz's work although our views are often different.).

  15. Using the Socioscientific Context of Climate Change to Teach Chemical Content and the Nature of Science

    Science.gov (United States)

    Flener-Lovitt, Charity

    2014-01-01

    A thematic course called "Climate Change: Chemistry and Controversy" was developed for upper-level non-STEM students. This course used the socioscientific context of climate change to teach chemical principles and the nature of science. Students used principles of agnotology (direct study of misinformation) to debunk climate change…

  16. Pre-service teachers and socio-scientific inquiry : Opportunities and challenges

    NARCIS (Netherlands)

    Knippels, M.C.P.J.; van Harskamp, M.; Verhoeff, R.P.; Postma, P.A.

    2017-01-01

    This paper presents the results of a teacher training program aiming to enable pre-service teachers to engage secondary education students in Socio-Scientific Inquiry-Based Learning (SSIBL). In SSIBL – an approach developed within the European project PARRISE – students formulate questions about

  17. Optimization as a Reasoning Strategy for Dealing with Socioscientific Decision-Making Situations

    Science.gov (United States)

    Papadouris, Nicos

    2012-01-01

    This paper reports on an attempt to help 12-year-old students develop a specific optimization strategy for selecting among possible solutions in socioscientific decision-making situations. We have developed teaching and learning materials for elaborating this strategy, and we have implemented them in two intact classes (N = 48). Prior to and after…

  18. College Students' Scientific Epistemological Views and Thinking Patterns in Socioscientific Decision Making

    Science.gov (United States)

    Liu, Shiang-Yao; Lin, Chuan-Shun; Tsai, Chin-Chung

    2011-01-01

    This study aims to test the nature of the assumption that there are relationships between scientific epistemological views (SEVs) and reasoning processes in socioscientific decision making. A mixed methodology that combines both qualitative and quantitative approaches of data collection and analysis was adopted not only to verify the assumption…

  19. Designing and Implementing Web-Based Scaffolding Tools for Technology-Enhanced Socioscientific Inquiry

    Science.gov (United States)

    Shin, Suhkyung; Brush, Thomas A.; Glazewski, Krista D.

    2017-01-01

    This study explores how web-based scaffolding tools provide instructional support while implementing a socio-scientific inquiry (SSI) unit in a science classroom. This case study focused on how students used web-based scaffolding tools during SSI activities, and how students perceived the SSI unit and the scaffolding tools embedded in the SSI…

  20. What's Natural about Nature? Deceptive Concepts in Socio-Scientific Decision-Making

    Science.gov (United States)

    Lindahl, Mats Gunnar; Linder, Cedric

    2015-01-01

    The conflicts between nature and nurture are brought to the fore and challenges socio-scientific decision-making in science education. The multitude of meanings of these concepts and their roles in societal discourses can impede students' development of understanding for different perspectives, e.g. on gene technology. This study problematizes…

  1. Implications of inherent safe nuclear power system

    International Nuclear Information System (INIS)

    Song, Yo-Taik

    1987-01-01

    The safety of present day nuclear power reactors and research reactors depends on a combination of design features of passive and active systems, and the alert judgement of their operators. A few inherently safe designs of nuclear reactors for power plants are currently under development. In these designs, the passive systems are emphasized, and the active systems are minimized. Also efforts are made to eliminate the potential for human failures that initiate the series of accidents. If a major system fails in these designs, the core is flooded automatically with coolants that flow by gravity, not by mechanical pumps or electromagnetic actuators. Depending on the choice of the coolants--water, liquid metal and helium gas--there are three principal types of inherently safe reactors. In this paper, these inherently safe reactor designs are reviewed and their implications are discussed. Further, future perspectives of their acceptance by nuclear industries are discussed. (author)

  2. Informing patients of risks inherent in treatment.

    Science.gov (United States)

    Griffith, Richard; Tengnah, Cassam

    2009-11-01

    Consent to treatment lies at the heart of autonomous decision making by patients who are entitled to make a free choice about whether to accept or refuse treatment. To help patients arrive at their decision district nurses must ensure that they give sufficient information about the nature and risks inherent in the treatment to allow an informed choice to be made. This article considers how much information regarding risks needs to be disclosed. It discusses how the law requires a different level of disclosure for patients who ask no questions about risks, those who make general enquiries about risks and those who ask specific questions about the risks inherent in treatment.

  3. Students' Perception of Live Lectures' Inherent Disadvantages

    Science.gov (United States)

    Petrovic, Juraj; Pale, Predrag

    2015-01-01

    This paper aims to provide insight into various properties of live lectures from the perspective of sophomore engineering students. In an anonymous online survey conducted at the Faculty of Electrical Engineering and Computing, University of Zagreb, we investigated students' opinions regarding lecture attendance, inherent disadvantages of live…

  4. An inherently safe power reactor module

    International Nuclear Information System (INIS)

    Salerno, L.N.

    1985-01-01

    General Electric's long participation in liquid metal reactor technology has led to a Power Reactor Inherently Safe Module (PRISM) concept supported by DOE contract DE-AC06-85NE37937. The reactor module is sized to maximize inherent safety features. The small size allows factory fabrication, reducing field construction and field QA/QC labor, and allows safety to be demonstrated in full scale, to support a pre-licensed standard commercial product. The module is small enough to be placed underground, and can be combined with steam and electrical generating equipment to provide a complete electrical power producing plant in the range of 400-1200 MWe. Initial assessments are that the concept has the potential to be economically competitive with existing methods of power production used by the utility industry

  5. Inherently safe technologies-chemical and nuclear

    International Nuclear Information System (INIS)

    Weinberg, A.M.

    1984-01-01

    Probabilistic risk assessments show an inverse relationship between the likelihood and the consequences of nuclear and chemical plant accidents, but the Bhopal accident has change public complacency about the safety of chemical plants to such an extent that public confidence is now at the same low level as with nuclear plants. The nuclear industry's response was to strengthen its institutions and improve its technologies, but the public may not be convinced. One solution is to develop reactors which do not depend upon the active intervention of humans of electromechanical devices to deal with emergencies, but which have physical properties that limit the possible temperature and power of a reactor. The Process Inherent Ultimately Safe and the modular High-Temperature Gas-Cooled reactors are two possibilities. the chemical industry needs to develop its own inherently safe design precepts that incorporate smallness, safe processes, and hardening against sabotage. 5 references

  6. A general index of inherent risk

    OpenAIRE

    Schnytzer, Adi; Westreich, Sara

    2009-01-01

    We extend the pioneering work of Aumann and Serrano by presenting an index of inherent riskiness of a gamble having the desirable properties of their index, while being applicable to gambles with either positive or negative expectations. As such, our index provides a measure of riskiness which is of use for both risk lovers and risk aversive gamblers, and is defined for all discrete and a large class of continuous gambles. We analyze abstract properties of our index, and present in addition t...

  7. Iser: an international inherently safe reactor concept

    International Nuclear Information System (INIS)

    Wakabayashi, Hiroaki

    1988-01-01

    Iser is a modular standardised 200-300 MWe power reactor based on the PIUS principle. It differs from PIUS in being simpler, and making full use of existing steel-vessel-based LWR technology. Iser is an inherently safe reactor concept under development in Japan. It is a generic concept, not a patented commodity, and it is expected that an international association to develop the concept will be formed. (U.K.)

  8. Integral fast reactor concept inherent safety features

    International Nuclear Information System (INIS)

    Marchaterre, J.F.; Sevy, R.H.; Cahalan, J.E.

    1987-01-01

    The Integral Fast Reactor (IFR) is an innovative liquid-metal-cooled reactor concept being developed at Argonne National Laboratory. The two major goals of the IFT development effort are improved economics and enhanced safety. The design features that together fulfill these goals are: 1) a liquid metal (sodium) coolant, 2) a pool-type reactor primary system configuration, 3) an advanced ternary alloy metallic fuel, and 4) an integral fuel cycle. This paper reviews the design features that contribute to the safety margins inherent to the IFR concept. Special emphasis is placed on the ability of the IFR design to accommodate anticipated transients without scram (ATWS)

  9. Integral Fast Reactor concept inherent safety features

    International Nuclear Information System (INIS)

    Marchaterre, J.F.; Sevy, R.H.; Cahalan, J.E.

    1986-01-01

    The Integral Fast Reactor (IFR) is an innovative liquid-metal-cooled reactor concept being developed at Argonne National Laboratory. The two major goals of the IFR development effort are improved economics and enhanced safety. The design features that together fulfill these goals are: (1) a liquid metal (sodium) coolant, (2) a pool-type reactor primary system configuration, (3) an advanced ternary alloy metallic fuel, and (4) an integral fuel cycle. This paper reviews the design features that contribute to the safety margins inherent to the IFR concept. Special emphasis is placed on the ability of the IFR design to accommodate anticipated transients without scram (ATWS)

  10. Is human fracture hematoma inherently angiogenic?

    LENUS (Irish Health Repository)

    Street, J

    2012-02-03

    This study attempts to explain the cellular events characterizing the changes seen in the medullary callus adjacent to the interfragmentary hematoma during the early stages of fracture healing. It also shows that human fracture hematoma contains the angiogenic cytokine vascular endothelial growth factor and has the inherent capability to induce angiogenesis and thus promote revascularization during bone repair. Patients undergoing emergency surgery for isolated bony injury were studied. Raised circulating levels of vascular endothelial growth factor were seen in all injured patients, whereas the fracture hematoma contained significantly higher levels of vascular endothelial growth factor than did plasma from these injured patients. However, incubation of endothelial cells in fracture hematoma supernatant significantly inhibited the in vitro angiogenic parameters of endothelial cell proliferation and microtubule formation. These phenomena are dependent on a local biochemical milieu that does not support cytokinesis. The hematoma potassium concentration is cytotoxic to endothelial cells and osteoblasts. Subcutaneous transplantation of the fracture hematoma into a murine wound model resulted in new blood vessel formation after hematoma resorption. This angiogenic effect is mediated by the significant concentrations of vascular endothelial growth factor found in the hematoma. This study identifies an angiogenic cytokine involved in human fracture healing and shows that fracture hematoma is inherently angiogenic. The differences between the in vitro and in vivo findings may explain the phenomenon of interfragmentary hematoma organization and resorption that precedes fracture revascularization.

  11. Inherently safe in situ uranium recovery

    International Nuclear Information System (INIS)

    Krumhansl, James Lee; Beauheim, Richard Louis; Brady, Patrick Vane; Arnold, Bill Walter; Kanney, Joseph F.; McKenna, Sean Andrew

    2009-01-01

    Expansion of uranium mining in the United States is a concern to some environmental groups and sovereign Native American Nations. An approach which may alleviate some problems is to develop inherently safe in situ uranium recovery ('ISR') technologies. Current ISR technology relies on chemical extraction of trace levels of uranium from aquifers that, once mined, can still contain dissolved uranium and other trace metals that are a health concern. Existing ISR operations are few in number; however, high uranium prices are driving the industry to consider expanding operations nation-wide. Environmental concerns and enforcement of the new 30 ppb uranium drinking water standard may make opening new mining operations more difficult and costly. Here we propose a technological fix: the development of inherently safe in situ recovery (ISISR) methods. The four central features of an ISISR approach are: (1) New 'green' leachants that break down predictably in the subsurface, leaving uranium, and associated trace metals, in an immobile form; (2) Post-leachant uranium/metals-immobilizing washes that provide a backup decontamination process; (3) An optimized well-field design that increases uranium recovery efficiency and minimizes excursions of contaminated water; and (4) A combined hydrologic/geochemical protocol for designing low-cost post-extraction long-term monitoring. ISISR would bring larger amounts of uranium to the surface, leave fewer toxic metals in the aquifer, and cost less to monitor safely - thus providing a 'win-win-win' solution to all stakeholders.

  12. Sensors and actuators inherent in biological species

    Science.gov (United States)

    Taya, Minoru; Stahlberg, Rainer; Li, Fanghong; Zhao, Ying Joyce

    2007-04-01

    This paper addresses examples of sensing and active mechanisms inherent in some biological species where both plants and animals cases are discussed: mechanosensors and actuators in Venus Fly Trap and cucumber tendrils, chemosensors in insects, two cases of interactions between different kingdoms, (i) cotton plant smart defense system and (ii) bird-of-paradise flower and hamming bird interaction. All these cases lead us to recognize how energy-efficient and flexible the biological sensors and actuators are. This review reveals the importance of integration of sensing and actuation functions into an autonomous system if we make biomimetic design of a set of new autonomous systems which can sense and actuate under a number of different stimuli and threats.

  13. The inherent limits of predicting school violence.

    Science.gov (United States)

    Mulvey, E P; Cauffman, E

    2001-10-01

    The recent media hype over school shootings has led to demands for methods of identifying school shooters before they act. Despite the fact that schools remain one of the safest places for youths to be, schools are beginning to adopt identification systems to determine which students could be future killers. The methods used to accomplish this not only are unproven but are inherently limited in usefulness and often do more harm than good for both the children and the school setting. The authors' goals in the present article are to place school shootings in perspective relative to other risks of violence that children face and to provide a reasonable and scientifically defensible approach to improving the safety of schools.

  14. Inherent Error in Asynchronous Digital Flight Controls.

    Science.gov (United States)

    1980-02-01

    operation will be eliminated. If T* is close to T, the inherent error (eA) is a small value. Then the deficiency of the basic model, which is de... tK2 at m ~VCONTR0RKIPPIL I~+ R tKT 2 TKT 5 ~I G E 1 i V OTN TRIL 2-REDN HNE IjT e UT 3 ~49__I 4.) 4 -4 - 4.-4 U 4.) k-4E-- Iz E-4 P E-44)-4. 4.)l 1s...indicate the channel failure. To reduce this deficiency , the new model computes a tolerance value equal to the maximum steady-state sample covariance of the

  15. Inherently safe in situ uranium recovery

    Science.gov (United States)

    Krumhansl, James L; Brady, Patrick V

    2014-04-29

    An in situ recovery of uranium operation involves circulating reactive fluids through an underground uranium deposit. These fluids contain chemicals that dissolve the uranium ore. Uranium is recovered from the fluids after they are pumped back to the surface. Chemicals used to accomplish this include complexing agents that are organic, readily degradable, and/or have a predictable lifetime in an aquifer. Efficiency is increased through development of organic agents targeted to complexing tetravalent uranium rather than hexavalent uranium. The operation provides for in situ immobilization of some oxy-anion pollutants under oxidizing conditions as well as reducing conditions. The operation also artificially reestablishes reducing conditions on the aquifer after uranium recovery is completed. With the ability to have the impacted aquifer reliably remediated, the uranium recovery operation can be considered inherently safe.

  16. Geometries inherent to N=1 supergravities

    International Nuclear Information System (INIS)

    Galperin, A.S.; Ogievetsky, V.I.; Sokatchev, E.S.

    1981-01-01

    The first part of the talk is devoted to a consideration of linearized N=1 supergravities. The second main part deals with complex geometries inherent to different N=1 supergravities. A special attention is paid to a new version with local symmetry. It is connected to the special nonminimal case (n=0) having a remarkable property of supervolume preservation in Csup(4.4) superspace. Therefore the superdeterminant of change of variables from left to right-handed Rsup(4.4) parametrization is a dimensionless scalar. This geometric invariant has to be constrained to obtain an action. Solving such a constraint on vector and spinor prepotentials in Wess-Zumino gauge one obtains the new supergravity with 12+12 fields and local symmetry. A possible relaxation of this constraint is briefly considered (16+16 fields version) [ru

  17. Magnetic latch trigger for inherent shutdown assembly

    International Nuclear Information System (INIS)

    Sowa, E.S.

    1976-01-01

    An inherent shutdown assembly for a nuclear reactor is provided. A neutron absorber is held ready to be inserted into the reactor core by a magnetic latch. The latch includes a magnet whose lines of force are linked by a yoke of material whose Curie point is at the critical temperature of the reactor at which the neutron absorber is to be inserted into the reactor core. The yoke is in contact with the core coolant or fissionable material so that when the coolant or the fissionable material increase in temperature above the Curie point the yoke loses its magnetic susceptibility and the magnetic link is broken, thereby causing the absorber to be released into the reactor core. 6 claims, 3 figures

  18. Inherent safety characteristics of innovative reactors

    International Nuclear Information System (INIS)

    Heil, J.A.

    1995-11-01

    The added safety value of innovative or third generation reactor designs has been evaluated in order to determine the most suitable candidate for Dutch government funded research and development support. To this end, four innovative reactor concepts, viz. PIUS (Process Inherent Ultimate Safety), PRISM (Power Reactor Innovative Small), HTR-M (High Temperature Reactor Module) and MHTGR (Modular High Temperature Gas-cooled Reactor), have been studied and their passive and inherent safety characteristics have been outlined. Also the outlook for further technological and industrial development has been considered. The results of the study confirm the perspective of the innovative reactors for reduced dependence on active safety provisions and for a further reduced vulnerability to technical failures and human errors. The accident responses to generic accident initiators, viz. reactivity and cooling accidents, and also to reactor specific accidents show that neither active safety systems nor short term operator actions are required for maintaining the reactor core in a controlled and coolable condition. Whether this gives rise to a higher total safety of the innovative reactor designs, compared to evolutionary or advanced reactors, cannot be concluded. Supplementary experimental and analytical analyses of reactor specific accidents are required to be able to assess the safety of these innovative designs in a more quantitative manner. It is believed that the safety case of innovative reactors, which are less dependent on active safety systems, can be communicated with the general public in a more transparent way. Considering the perspective for further technological and industrial development it is not expected that any of the considered innovative reactor concepts will become commercially available within the next one to two decades. However, they could be made available earlier if they would receive sufficient financial backing. Considering the added safety perspectives

  19. Weighing in on Genetic Engineering and Morality: Students Reveal Their Ideas, Expectations, and Reservations.

    Science.gov (United States)

    Sadler, Troy D.; Zeidler, Dana L.

    The ability to negotiate and resolve socioscientific issues has been posited as integral components of scientific literacy. Although philosophers and science educators have argued that socioscientific issues inherently involve moral and ethical considerations, the ultimate arbiters of morality are individual decision-makers. This study explored…

  20. Conceptual design of inherently safe integral reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J. I.; Chang, M. H.; Lee, D. J. and others

    1999-03-01

    The design concept of a 300 MWt inherently safe integral reactor(ISIR) for the propulsion of extra large and superhigh speed container ship was developed in this report. The scope and contents of this report are as follows : 1. The state of the art of the technology for ship-mounted reactor 2. Design requirements for ISIR 3. Fuel and core design 4. Conceptual design of fluid system 5. Conceptual design of reactor vessel assembly and primary components 6. Performance analyses and safety analyses. Installation of two ISIRs with total thermal power of 600MWt and efficiency of 21% is capable of generating shaft power of 126,000kW which is sufficient to power a container ship of 8,000TEU with 30knot cruise speed. Larger and speedier ship can be considered by installing 4 ISIRs. Even though the ISIR was developed for ship propulsion, it can be used also for a multi-purpose nuclear power plant for electricity generation, local heating, or seawater desalination by mounting on a movable floating barge. (author)

  1. The Inherent Asymmetry of DNA Replication.

    Science.gov (United States)

    Snedeker, Jonathan; Wooten, Matthew; Chen, Xin

    2017-10-06

    Semiconservative DNA replication has provided an elegant solution to the fundamental problem of how life is able to proliferate in a way that allows cells, organisms, and populations to survive and replicate many times over. Somewhat lost, however, in our admiration for this mechanism is an appreciation for the asymmetries that occur in the process of DNA replication. As we discuss in this review, these asymmetries arise as a consequence of the structure of the DNA molecule and the enzymatic mechanism of DNA synthesis. Increasing evidence suggests that asymmetries in DNA replication are able to play a central role in the processes of adaptation and evolution by shaping the mutagenic landscape of cells. Additionally, in eukaryotes, recent work has demonstrated that the inherent asymmetries in DNA replication may play an important role in the process of chromatin replication. As chromatin plays an essential role in defining cell identity, asymmetries generated during the process of DNA replication may play critical roles in cell fate decisions related to patterning and development.

  2. Improved inherent safety in liquid fuel reactors

    International Nuclear Information System (INIS)

    Taube, M.

    1982-01-01

    The molten salt reactor system divided into core (thermal and fast) and breeding zone (fission breeder reactor, fusion hybrid system, accelerator-spallation system) has some unique inherent safety properties: a) reduced inventory of fission products during normal operation due to on-line chemical reprocessing and in-core gas purging; b) fast removal of freshly bred fissile nuclides and fission products from the breeding zone (the so called suppressed fission system); c) pressureless fuel and primary coolant system; d) elimination of the possibility of a violent exoenergetic chemical reaction with air, water or metals; e) elimination of the possibility of gaseous hydrogen production during an accident; f) provides a non-engineered feature of dumping of fuel from the core and heat exchanger to a safe drain tank; g) presence of a large heat sink in the form of an inactive diluent salt; h) possibility of natural convection heat removal during an accident and even normal operation (by means of gas lifting); i) dissipation of the remaining decayheat by spraying water on the containment from outside, which allows to manage the worst accident; i) Even in the case of the destruction in the war by conventional or nuclear weapon the contaminated land is significantly reduced. The world-wide present activity in the field of molten salt technology is reviewed. (orig.)

  3. Indicators of Informal and Formal Decision-Making about a Socioscientific Issue

    Science.gov (United States)

    Dauer, Jenny M.; Lute, Michelle L.; Straka, Olivia

    2017-01-01

    We propose two contrasting types of student decision-making based on social and cognitive psychology models of separate mental processes for problem solving. Informal decision-making uses intuitive reasoning and is subject to cognitive biases, whereas formal decision-making uses effortful, logical reasoning. We explored indicators of students'…

  4. Debate on Global Warming as a Socio-Scientific Issue: Science Teaching towards Political Literacy

    Science.gov (United States)

    Pereira dos Santos, Wildson Luiz

    2014-01-01

    The focus of this response to the original article by Tom G. H. Bryce and Stephen P. Day ("Cult Stud Sci Educ." doi:10.1007/s11422-012-9407-1, 2013) is the use of empirical data to illustrate and expand the understanding of key points of their argument. Initially, I seek to discuss possible answers to the three questions posed by the…

  5. Process Inherent Ultimate Safety (PIUS) reactor evaluation study: Final report

    International Nuclear Information System (INIS)

    1987-02-01

    This report presents the results of an independent study by United Engineers and Constructors (UNITED) of the SECURE-P Process Inherent Ultimate Safety (PIUS) Reactor Concept which is presently under development by the Swedish light water reactor vendor ASEA-ATOM of Vasteras, Sweden. This study was performed to investigate whether there is any realistic basis for believing that the PIUS reactor could be a viable competitor in the US energy market in the future. Assessments were limited to the technical, economic and licensing aspects of PIUS. Socio-political issues, while certainly important in answering this question, are so broad and elusive that it was considered that addressing them with the limited perspective of one small group from one company would be of questionable value and likely be misleading. Socio-political issues aside, the key issue is economics. For this reason, the specific objectives of this study were to determine if the estimated PIUS plant cost will be competitive in the US market and to identify and evaluate the technical and licensing risks that might make PIUS uneconomical or otherwise unacceptable

  6. The inherent contradictions in data protection law

    DEFF Research Database (Denmark)

    Blume, Peter Erik

    2012-01-01

    . • Transparency is seen as important and through an information policy, real transparency may be achieved. • Another issue concerns whether it is expedient that the same data protection rules apply to the private and to the public sector. Having separate rules should be considered, as this would give the rules...

  7. Measurement of inherent optical properties in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Suresh, T.; Desa, E.; Kurian, J.; Mascarenhas, A.A.M.Q.

    Inherent optical properties, absorption and began attenuation were measured in situ using a reflective tube absorption meter at nint wavelength, 412, 440, 488, 510, 555, 630, 650, 676 and 715 nm, in the Arabian Sea during March. Since inherent...

  8. Inherent/passive safety in fusion power plants

    International Nuclear Information System (INIS)

    Piet, S.J.; Crocker, J.G.

    1986-01-01

    The concept of inherent or passive safety for fusion energy is explored, defined, and partially quantified. Four levels of safety assurance are defined, which range from true inherent safety to passive safety to protection via active engineered safeguard systems. Fusion has the clear potential for achieving inherent or passive safety, which should be an objective of fusion research and design. Proper material choice might lead to both inherent/passive safety and high mass power density, improving both safety and economics. When inherent or passive safety is accomplished, fusion will be well on the way to achieving its ultimate potential and to be a truly superior energy source for the future

  9. Inherent Controls on Ready Mix Cement Silos

    Science.gov (United States)

    This document may be of assistance in applying the New Source Review (NSR) air permitting regulations including the Prevention of Significant Deterioration (PSD) requirements. This document is part of the NSR Policy and Guidance Database. Some documents in the database are a scanned or retyped version of a paper photocopy of the original. Although we have taken considerable effort to quality assure the documents, some may contain typographical errors. Contact the office that issued the document if you need a copy of the original.

  10. The Effect of Socioscientific Topics on Discourse within an Online Game Designed to Engage Middle School Students in Scientific Argumentation

    Science.gov (United States)

    Craig-Hare, Jana; Ault, Marilyn; Rowland, Amber

    2017-01-01

    The purpose of this study was to investigate the types of argumentation discourse displayed by students when they engaged in chat as part of an online multiplayer game about both socioscientific and scientific topics. Specifically, this study analyzed discourse episodes created by middle school students as they discussed scientific and…

  11. A real-life example of choosing an inherently safer process option

    International Nuclear Information System (INIS)

    Study, Karen

    2007-01-01

    While choosing an inherently safer alternative may seem straightforward, sometimes what seems to be the most obvious alternative may not provide the best risk reduction. The process designer must maintain a broad perspective to be able to recognize all potential hazards when evaluating design options. All aspects of operation such as start-up, shut-down, utility failure, as well as normal operation should be considered. Choosing the inherently safer option is best accomplished early in the option selection phase of a project; however, recycle back to the option selection phase may be needed if an option is not thoroughly evaluated early in the process. In this paper, a project to supply ammonia to a catalytic reactor will be reviewed. During the course of the project, an 'inherently safer' alternative was selected and later discarded due to issues uncovered during the detail design phase. The final option chosen will be compared to (1) the original design and (2) the initial 'inherently safer' alternative. The final option was inherently safer than both the original design and the initial 'inherently safer' alternative even though the design team initially believed that it would not be

  12. The inherently-safe power reactor DYONISOS (Dynamic Nuclear Inherently-Safe Reactor Operating with Spheres)

    International Nuclear Information System (INIS)

    Taube, M.; Lanfranchi, M.; Weissenfluh, Th. von; Ligou, J.; Yadigaroglu, G.; Taube, P.

    1986-01-01

    A philosophy of inherent safety is formulated and an inherently-safe thermal power reactor is presented. Solid fuel in the form of spheres a few centimetres in diameter is suspended under the hydro-dynamic pressure of molten lead coolant in vertical channels within the graphite moderator. Loss of main pump pressure, or a loss-of-coolant accident (LOCA), results in immediate removal of the fuel to rigid sieves below the core, with consequent subcriticality. Residual and decay heat are carried away by thermal conduction through the coolant or, in the case of a LOCA, by a combination of radiation and natural convection of cover gas or incoming air from the fuel to the reactor vessel and convection of air between the vessel and steel containment wall. All decay heat removal systems are passive, though actively initiated external spray cooling of the containment can be used to reduce wall temperature. This, however, is only necessary in the case of a LOCA and after a period of 24 h. (author)

  13. The Development of a Socioscientific Issues-Based Curriculum Unit for Middle School Students: Global Warming Issue

    Science.gov (United States)

    Atabey, Nejla; Topçu, Mustafa Sami

    2017-01-01

    In this study, we aimed at developing "Human and Environment" unit around SSI based instruction. We followed action research methodology in development and implementation of the unit. The participants of this study were 24 seventh graders students and the instruction was extended to eight and a half weeks, taking four hours in a week.…

  14. Pair creation at large inherent angles

    International Nuclear Information System (INIS)

    Chen, P.; Tauchi, T.; Schroeder, D.V.

    1992-01-01

    In the next-generation linear colliders, the low-energy e + e - pairs created during the collision of high-energy e + e - beams would cause potential deleterious background problems to the detectors. At low collider energies, the pairs are made essentially by the incoherent process, where the pair is created by the interaction of beamstrahlung photons on the individual particles in the oncoming beam. This problem was first identified by Zolotarev, et al. At energies where the beamstrahlung parameter Υ lies approximately in the range 0.6 approx-lt Υ approx-lt 100, pair creation from the beamstrahlung photons is dominated by a coherent process, first noted by Chen. The seriousness of this pair creation problem lies in the transverse momenta that the pair particles carry when leaving the interaction point (IP) with large angles. Since the central issue is the transverse momentum for particles with large angles, the authors notice that there is another source for it. Namely, when the pair particles are created at low energies, the intrinsic angles of these pairs when produced may already be large. In this paper they reinvestigate the problem, following essentially the same equivalent photon approach, but with changes in specific details including the virtual photon spectrum. In addition, various assumptions are made more explicit. The formulas derived are then applied to the collider parameters designed by Palmer

  15. Inherent safety features in balance-of-plant layout

    International Nuclear Information System (INIS)

    Wattelet, P.L.; Green, K.J.

    1992-01-01

    Future nuclear units must be more economical to construct and operate, and, at the same time, clearly incorporate advances in safety over the current generation of light water reactors. To achieve these goals, the root causes of safety issues must be addressed. In this way, global, cost-effective solutions can be implemented. With simple, direct design approaches, the licensing risk is minimized and configuration control is enhanced. With proper planning in the early stages of plant design, postulated accidents and events can often be mitigated by passive features inherent in the basic structure and layout, eliminating expensive added protective structures and components often found in current designs. Korea Electric Power Corporation's Yonggwang (YGN) Units 3 and 4, shown in an artist's rendering in Figure 1, are now under construction in Korea. Engineering is more than 85% complete, and Unit 3 construction is more than 50% complete. Significant steps toward design simplification and safety enhancement have been made by addressing safety concerns very early in the design effort. The tools used to achieve this were improved symmetry and separation, isolation of potential hazards, and an improved design process

  16. Does the inherence heuristic take us to psychological essentialism?

    Science.gov (United States)

    Marmodoro, Anna; Murphy, Robin A; Baker, A G

    2014-10-01

    We argue that the claim that essence-based causal explanations emerge, hydra-like, from an inherence heuristic is incomplete. No plausible mechanism for the transition from concrete properties, or cues, to essences is provided. Moreover, the fundamental shotgun and storytelling mechanisms of the inherence heuristic are not clearly enough specified to distinguish them, developmentally, from associative or causal networks.

  17. Where Did You Come From? Where Will You Go? Human Evolutionary Biology Education and American Students' Academic Interests and Achievements, Professional Goals, and Socioscientific Decision-making

    Science.gov (United States)

    Schrein, Caitlin M.

    In the United States, there is a national agenda to increase the number of qualified science, technology, engineering, and maths (STEM) professionals and a movement to promote science literacy among the general public. This project explores the association between formal human evolutionary biology education (HEB) and high school science class enrollment, academic achievement, interest in a STEM degree program, motivation to pursue a STEM career, and socioscientific decision-making for a sample of students enrolled full-time at Arizona State University. Given a lack of a priori knowledge of these relationships, the Grounded Theory Method was used and was the foundation for a mixed-methods analysis involving qualitative and quantitative data from one-on-one interviews, focus groups, questionnaires, and an online survey. Theory development and hypothesis generation were based on data from 44 students. The survey instrument, developed to test the hypotheses, was completed by 486 undergraduates, age 18--22, who graduated from U.S. public high schools. The results showed that higher exposure to HEB was correlated with greater high school science class enrollment, particularly for advanced biological science classes, and that, for some students, HEB exposure may have influenced their enrollment, because the students found the content interesting and relevant. The results also suggested that students with higher K--12 HEB exposure felt more prepared for undergraduate science coursework. There was a positive correlation between HEB exposure and interest in a STEM degree and an indirect relationship between higher HEB exposure and motivation to pursue a STEM career. Regarding a number of socioscientific issues, including but not limited to climate change, homosexuality, and stem cell research, students' behaviors and decision-making more closely reflected a scientific viewpoint---or less-closely aligned to a religion-based perspective---when students had greater HEB exposure

  18. Socio-scientific research contribution to energy practice; Sozialwissenschaftlicher Forschungsbeitrag fuer die Energiepraxis

    Energy Technology Data Exchange (ETDEWEB)

    Artho, J.; Soland, M.

    2009-01-15

    This final report for the Swiss Federal Office of Energy (SFOE) takes a look at the findings of a study made by the University of Zurich, Switzerland, on socio-scientific aspects of energy use. Basic socio-psychological mechanisms are examined on which energy policy instruments can be based. Basic mechanisms are discussed such as enforced behaviour, non-enforced action, habitual acts and action taken on the basis of heuristics and rules-of-thumb. The second part of the paper looks at examples of the use of these principles, discussing, amongst other things, cost-benefit and moral reasoning, habits, mental accounting and boomerang effects. Finally the analyses are summarised and further research needed as a result of these analyses is noted.

  19. Development of physiotherapy inherent requirement statements - an Australian experience.

    Science.gov (United States)

    Bialocerkowski, Andrea; Johnson, Amanda; Allan, Trevor; Phillips, Kirrilee

    2013-04-16

    The United Nations Convention on the Rights of People with Disabilities promotes equal rights of people with a disability in all aspects of their life including their education. In Australia, Disability Discrimination legislation underpins this Convention. It mandates that higher education providers must demonstrate that no discrimination has occurred and all reasonable accommodations have been considered and implemented, to facilitate access and inclusion for a student with a disability. The first step to meeting legislative requirements is to provide students with information on the inherent requirements of a course. This paper describes the steps which were taken to develop inherent requirement statements for a 4-year entry-level physiotherapy program at one Australian university. Inherent requirement statements were developed using an existing framework, which was endorsed and mandated by the University. Items which described inherencies were extracted from Australian physiotherapy professional standards and statutory regulatory requirements, and units contained in the physiotherapy program. Data were integrated into the 8 prescribed domains: ethical behaviour, behavioural stability, legal, communication, cognition, sensory abilities, strength and mobility, and sustainable performance. Statements for each domain were developed using a 5-level framework (introductory statement, description of the inherent requirement, justification for inherency, characteristics of reasonable adjustments and exemplars) and reviewed by a University Review Panel. Refinement of statements continued until no further changes were required. Fifteen physiotherapy inherent requirement statements were developed. The eight domains identified in the existing framework, developed for Nursing, were relevant to the study of physiotherapy. The inherent requirement statements developed in this study provide a transparent, defensible position on the current requirements of physiotherapy study at

  20. Development of physiotherapy inherent requirement statements – an Australian experience

    Science.gov (United States)

    2013-01-01

    Background The United Nations Convention on the Rights of People with Disabilities promotes equal rights of people with a disability in all aspects of their life including their education. In Australia, Disability Discrimination legislation underpins this Convention. It mandates that higher education providers must demonstrate that no discrimination has occurred and all reasonable accommodations have been considered and implemented, to facilitate access and inclusion for a student with a disability. The first step to meeting legislative requirements is to provide students with information on the inherent requirements of a course. This paper describes the steps which were taken to develop inherent requirement statements for a 4-year entry-level physiotherapy program at one Australian university. Case presentation Inherent requirement statements were developed using an existing framework, which was endorsed and mandated by the University. Items which described inherencies were extracted from Australian physiotherapy professional standards and statutory regulatory requirements, and units contained in the physiotherapy program. Data were integrated into the 8 prescribed domains: ethical behaviour, behavioural stability, legal, communication, cognition, sensory abilities, strength and mobility, and sustainable performance. Statements for each domain were developed using a 5-level framework (introductory statement, description of the inherent requirement, justification for inherency, characteristics of reasonable adjustments and exemplars) and reviewed by a University Review Panel. Refinement of statements continued until no further changes were required. Fifteen physiotherapy inherent requirement statements were developed. The eight domains identified in the existing framework, developed for Nursing, were relevant to the study of physiotherapy. Conclusions The inherent requirement statements developed in this study provide a transparent, defensible position on the

  1. Changes in Pre-service Science Teachers' Understandings After Being Involved in Explicit Nature of Science and Socioscientific Argumentation Processes

    Science.gov (United States)

    Kutluca, A. Y.; Aydın, A.

    2017-08-01

    The study explored the changes in pre-service science teachers' understanding of the nature of science and their opinions about the nature of science, science teaching and argumentation after their participation in explicit nature of science (NOS) and socioscientific argumentation processes. The participants were 56 third-grade pre-service science teachers studying in a state university in Turkey. The treatment group comprised 27 participants, and there were 29 participants in the comparison group. The comparison group participants were involved in a student-centred science-teaching process, and the participants of the treatment group were involved in explicit NOS and socioscientific argumentation processes. In the study, which lasted a total of 11 weeks, a NOS-as-argumentation questionnaire was administered to all the participants to determine their understanding of NOS at the beginning and end of the data collection process, and six random participants of the treatment group participated in semi-structured interview questions in order to further understand their views regarding NOS, science teaching and argumentation. Qualitative and quantitative data analysis revealed that the explicit NOS and socioscientific argumentation processes had a significant effect on pre-service science teachers' NOS understandings. Furthermore, NOS, argumentation and science teaching views of the participants in the treatment group showed a positive change. The results of this study are discussed in light of the related literature, and suggestions are made within the context of contribution to science-teaching literature, improvement of education quality and education of pre-service teachers.

  2. Inherent Anticipation in the Pharmaceutical and Biotechnology Industries.

    Science.gov (United States)

    Goldman, Michael; Evans, Georgia; Zappia, Andrew

    2015-04-15

    Pharmaceutical and biotech research often involves discovering new properties of, or new methods to use, existing compositions. The doctrine of inherent anticipation, however, prevents the issuance and/or validity of a patent for discoveries deemed to have been implicitly disclosed in the prior art. This can be a barrier to patent rights in these technologies. Inherent anticipation therefore creates uncertainty for patent protection in the pharmaceutical and biotech sciences. Despite this uncertainty, Federal Circuit jurisprudence provides guidance on the boundaries of the inherent anticipation doctrine. In view of the case law, certain strategies may be employed to protect inventions that may potentially be viewed as inherent in the prior art. Copyright © 2015 Cold Spring Harbor Laboratory Press; all rights reserved.

  3. Non-technical issues in safety assessments for nuclear disposal facilities

    International Nuclear Information System (INIS)

    Kallenbach-Herbert, Beate; Brohmann, Bettina

    2010-09-01

    The paper highlights that a comprehensive approach to safety affords the consideration of technology, organisation, personnel and social environment. In several safety relevant contexts of nuclear waste disposal these fields are closely interrelated. The approach for the consideration of socio-scientific aspects which is sketched in this paper supports the systematic treatment of safety relevant non-technical issues in the safety case or in safety assessments for a disposal project. Furthermore it may foster the dialogue among specialists from the technical, the natural- and the socio-scientific field on questions of disposal safety. In this way it may contribute to a better understanding among the affected scientific disciplines in nuclear waste disposal.

  4. Mitigation of Severe Accident Consequences Using Inherent Safety Principles

    International Nuclear Information System (INIS)

    Wigeland, R.A.; Cahalan, J.E.

    2009-01-01

    Sodium-cooled fast reactors are designed to have a high level of safety. Events of high probability of occurrence are typically handled without consequence through reliable engineering systems and good design practices. For accidents of lower probability, the initiating events are characterized by larger and more numerous challenges to the reactor system, such as failure of one or more major engineered systems and can also include a failure to scram the reactor in response. As the initiating conditions become more severe, they have the potential for creating serious consequences of potential safety significance, including fuel melting, fuel pin disruption and recriticality. If the progression of such accidents is not mitigated by design features of the reactor, energetic events and dispersal of radioactive materials may result. For severe accidents, there are several approaches that can be used to mitigate the consequences of such severe accident initiators, which typically include fuel pin failures and core disruption. One approach is to increase the reliability of the reactor protection system so that the probability of an ATWS event is reduced to less than 1 x 10-6 per reactor year, where larger accident consequences are allowed, meeting the U.S. NRC goal of relegating such accident consequences as core disruption to these extremely low probabilities. The main difficulty with this approach is to convincingly test and guarantee such increased reliability. Another approach is to increase the redundancy of the reactor scram system, which can also reduce the probability of an ATWS event to a frequency of less than 1 x 10-6 per reactor year or lower. The issues with this approach are more related to reactor core design, with the need for a greater number of control rod positions in the reactor core and the associated increase in complexity of the reactor protection system. A third approach is to use the inherent reactivity feedback that occurs in a fast reactor to

  5. Inherent-opening-controlled pattern formation in carbon nanotube arrays

    International Nuclear Information System (INIS)

    Huang Xiao; Zhou, Jijie J; Sansom, Elijah; Gharib, Morteza; Haur, Sow Chorng

    2007-01-01

    We have introduced inherent openings into densely packed carbon nanotube arrays to study self-organized pattern formation when the arrays undergo a wetting-dewetting treatment from nanotube tips. These inherent openings, made of circular or elongated hollows in nanotube mats, serve as dewetting centres, from where liquid recedes from. As the dewetting centres initiate dry zones and the dry zones expand, surrounding nanotubes are pulled away from the dewetting centres by liquid surface tension. Among short nanotubes, the self-organized patterns are consistent with the shape of the inherent openings, i.e. slender openings lead to elongated trench-like structures, and circular holes result in relatively round nest-like arrangements. Nanotubes in a relatively high mat are more connected, like in an elastic body, than those in a short mat. Small cracks often initialize themselves in a relatively high mat, along two or more adjacent round openings; each of the cracks evolves into a trench as liquid dries up. Self-organized pattern control with inherent openings needs to initiate the dewetting process above the nanotube tips. If there is no liquid on top, inherent openings barely enlarge themselves after the wetting-dewetting treatment

  6. Cost-competitive, inherently safe LFMBR pool plant

    International Nuclear Information System (INIS)

    McDonald, J.S.; Brunings, J.E.; Chang, Y.I.; Hren, R.R.; Seidensticker, R.W.

    1984-01-01

    The Cost-Competitive, Inherently Safe LMFBR Pool Plant design was prepared in GFY 1983 under a DOE-sponsored program. This plant design was developed as a joint effort by Rockwell International and the Argonne National Laboratory with major contributions from the Bechtel Group, Inc.; Combustion engineering, Inc.; the Chicago Bridge and Iron Company; and the General Electric Company. Using current LMFBR technology, many innovative features were developed and incorporated into the design to meet the ultimate objectives of the Breeder Program, i.e., energy costs competitive with LWRs and inherent safety features to maintain the plant in a safe condition following assumed accidents without requiring operator action. This paper provides a description of the principal features that were incorporated into the design to achieve low cost and inherent safety

  7. The inherent politics of quality in public park management

    DEFF Research Database (Denmark)

    Lindholst, Andrej Christian; Konijnendijk, Cecil Cornelis; Fors, Hanna

    2012-01-01

    In this paper, we highlight and illustrate the inherent politics embedded in “quality” as a concept for managing public parks. Reflecting more generic quality concepts, contemporary quality models in park management include concepts for both operational, strategic and stakeholder management as well...... managing the park organisation itself. However, quality concepts and their application through various management models include as well as exclude the access, values and worldviews of particular interests. In this way, any particular quality concept and model embeds its own politics by inherent...... allocations of ‘who gets what, when and how’. We illustrate the inherent politics by providing a case study of a widely adopted quality model for operational management that has been adopted and implemented in Denmark as part of new public management reforms. In perspective, other quality concepts and models...

  8. A simplified analysis of uncertainty propagation in inherently controlled ATWS events

    International Nuclear Information System (INIS)

    Wade, D.C.

    1987-01-01

    The quasi static approach can be used to provide useful insight concerning the propagation of uncertainties in the inherent response to ATWS events. At issue is how uncertainties in the reactivity coefficients and in the thermal-hydraulics and materials properties propagate to yield uncertainties in the asymptotic temperatures attained upon inherent shutdown. The basic notion to be quantified is that many of the same physical phenomena contribute to both the reactivity increase of power reduction and the reactivity decrease of core temperature rise. Since these reactivities cancel by definition, a good deal of uncertainty cancellation must also occur of necessity. For example, if the Doppler coefficient is overpredicted, too large a positive reactivity insertion is predicted upon power reduction and collapse of the ΔT across the fuel pin. However, too large a negative reactivity is also predicted upon the compensating increase in the isothermal core average temperature - which includes the fuel Doppler effect

  9. "A Fiber Optic Ethernet With Inherent Migration Capability To FDDI"

    Science.gov (United States)

    Ferris, Kenneth D.; Chan, Tammy S.

    1988-12-01

    A Local Area Network (LAN) designed to a standard commercial interface, the Institute of Electrical and Electronics Engineers (IEEE) 802.3 or Ethernet, has been developed using fiber optics as the physical medium. The LAN, WhisperNet, operates in an active ring and thus has an inherent low cost migration path to a Fiber Distributed Data Interface (FDDI) implementation.

  10. The distribution of inherent phosphorus in fifteen water treatment ...

    African Journals Online (AJOL)

    The aim of this investigation was to characterise the chemical properties relevant to P-sorption/desorption processes of 15 South African WTR and to determine the inherent distribution of P within the WTR using a chemical fractionation procedure. The pH, exchangeable Ca and organic carbon content ranged from 4.77 to ...

  11. The application of probabilistic risk assessment to inherently safe reactors

    International Nuclear Information System (INIS)

    Cave, L.; Kastenberg, W.E.

    1987-01-01

    In the development of safety goals and design criteria for 'inherently safe' reactors a question which arises is 'To what extent is PRA relevant.' To answer this question it is necessary to consider both the risk to the public and the investment risk to the utility. In this paper the factors which are likely to determine safety objectives and their allocation are presented. (orig.)

  12. Influence of Inherent Moisture Content on the Deformation ...

    African Journals Online (AJOL)

    Influence of Inherent Moisture Content on the Deformation. Properties of Coconut Tissues During Mechanical Oil. Expression. *J. J. Mpagalile1 and B. Clarke2. 1Department of ... The study confirmed that moisture content has an important role in the deformation of coconut ..... A micro penetration technique for mechanical.

  13. Tactical supply chain planning models with inherent flexibility

    DEFF Research Database (Denmark)

    Esmaeilikia, Masoud; Fahimnia, Behnam; Sarkis, Joeseph

    2016-01-01

    Supply chains (SCs) can be managed at many levels. The use of tactical SC planning models with multiple flexibility options can help manage the usual operations efficiently and effectively, whilst improve the SC resiliency in response to inherent environmental uncertainties. This paper defines ta...

  14. Inherently safe high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Yamada, Masao; Hayakawa, Hitoshi

    1987-01-01

    It is recognized in general that High Temperature Gas-cooled Reactors have remarkable characteristics in inherent safety and it is well known that credits of the time margin have been admitted for accident evaluation in the licensing of the currently operating prototype HTGRs (300 MWe class). Recently, more inherently safe HTGRs are being developed in various countries and drawing attention on their possibility for urban siting. The inherent safety characteristics of these HTRs differ each other depending on their design philosophy and on the features of the components/structures which constitute the plant. At first, the specific features/characteristics of the elemental components/structures of the HTRs are explained one by one and then the overall safety features/characteristics of these HTR plants are explained in connection with their design philosophy and combination of the elemental features. Taking the KWU/Interatom Modular Reactor System as an example, the particular design philosophy and safety characteristics of the inherently safe HTR are explained with a result of preliminary evaluation on the possibility of siting close to densely populated area. (author)

  15. Inherent reactor power controller for a metal-fueled ALMR

    International Nuclear Information System (INIS)

    Wood, R.T.; Wilson, T.L. Jr.

    1990-01-01

    Inherent power control for metal-fueled ALMR designs involves using reactivity thermal feedback effects to control reactor power. This paper describes how, using classical control design techniques, a control system for normal load following maneuvers was deigned for a pool-type ALMR. This design provides active control of power removal in the balance of plant, direct control of selected primary and intermediate loop temperatures, and passive control of reactor power. The inherent stability of the strong, fast reactivity feedback effects bring heat production in the core into balance with the heat removal system temperatures, which are controlled to meet power demand. A simulation of the control system successfully responded to a 10% step change in power demand by changing power at an acceptable rate without causing large temperature fluctuations or exceeding thermal limits

  16. Observation and analysis of water inherent optical properties

    Science.gov (United States)

    Sun, Deyong; Li, Yunmei; Le, Chengfeng; Huang, Changchun

    2008-03-01

    Inherent optical property is an important part of water optical properties, and is the foundation of water color analytical model establishment. Through quantity filter technology (QFT) and backscattering meter BB9 (WETlabs Inc), absorption coefficients of CDOM, total suspended minerals and backscattering coefficients of total suspended minerals had been observed in Meiliang Bay of Taihu lake at summer and winter respectively. After analyzing the spectral characteristics of absorption and backscattering coefficients, the differences between two seasons had been illustrated adequately, and the reasons for the phenomena, which are related to the changes of water quality coefficient, had also been explained. So water environment states can be reflected by inherent optical properties. In addition, the relationship models between backscattering coefficients and suspended particle concentrations had been established, which can support coefficients for analytical models.

  17. Changes in Pre-Service Science Teachers' Understandings After Being Involved in Explicit Nature of Science and Socioscientific Argumentation Processes

    Science.gov (United States)

    Kutluca, A. Y.; Aydin, A.

    2017-01-01

    The study explored the changes in pre-service science teachers' understanding of the nature of science and their opinions about the nature of science, science teaching and argumentation after their participation in explicit nature of science (NOS) and socioscientific argumentation processes. The participants were 56 third-grade pre-service science…

  18. Science Education: Issues, Approaches and Challenges

    Directory of Open Access Journals (Sweden)

    Shairose Irfan Jessani

    2015-06-01

    Full Text Available In today’s global education system, science education is much more than fact-based knowledge. Science education becomes meaningless and incomprehensible for learners, if the learners are unable to relate it with their lives. It is thus recommended that Pakistan, like many other countries worldwide should adopt Science Technology Society (STS approach for delivery of science education. The purpose of the STS approach lies in developing scientifically literate citizens who can make conscious decisions about the socio-scientific issues that impact their lives. The challenges in adopting this approach for Pakistan lie in four areas that will completely need to be revamped according to STS approach. These areas include: the examination system; science textbooks; science teacher education programs; and available resources and school facilities.

  19. Posttest analysis of the FFTF inherent safety tests

    International Nuclear Information System (INIS)

    Padilla, A. Jr.; Claybrook, S.W.

    1987-01-01

    Inherent safety tests were performed during 1986 in the 400-MW (thermal) Fast Flux Test Facility (FFTF) reactor to demonstrate the effectiveness of an inherent shutdown device called the gas expansion module (GEM). The GEM device provided a strong negative reactivity feedback during loss-of-flow conditions by increasing the neutron leakage as a result of an expanding gas bubble. The best-estimate pretest calculations for these tests were performed using the IANUS plant analysis code (Westinghouse Electric Corporation proprietary code) and the MELT/SIEX3 core analysis code. These two codes were also used to perform the required operational safety analyses for the FFTF reactor and plant. Although it was intended to also use the SASSYS systems (core and plant) analysis code, the calibration of the SASSYS code for FFTF core and plant analysis was not completed in time to perform pretest analyses. The purpose of this paper is to present the results of the posttest analysis of the 1986 FFTF inherent safety tests using the SASSYS code

  20. On the maximum entropy distributions of inherently positive nuclear data

    Energy Technology Data Exchange (ETDEWEB)

    Taavitsainen, A., E-mail: aapo.taavitsainen@gmail.com; Vanhanen, R.

    2017-05-11

    The multivariate log-normal distribution is used by many authors and statistical uncertainty propagation programs for inherently positive quantities. Sometimes it is claimed that the log-normal distribution results from the maximum entropy principle, if only means, covariances and inherent positiveness of quantities are known or assumed to be known. In this article we show that this is not true. Assuming a constant prior distribution, the maximum entropy distribution is in fact a truncated multivariate normal distribution – whenever it exists. However, its practical application to multidimensional cases is hindered by lack of a method to compute its location and scale parameters from means and covariances. Therefore, regardless of its theoretical disadvantage, use of other distributions seems to be a practical necessity. - Highlights: • Statistical uncertainty propagation requires a sampling distribution. • The objective distribution of inherently positive quantities is determined. • The objectivity is based on the maximum entropy principle. • The maximum entropy distribution is the truncated normal distribution. • Applicability of log-normal or normal distribution approximation is limited.

  1. Inherent Conservatism in Deterministic Quasi-Static Structural Analysis

    Science.gov (United States)

    Verderaime, V.

    1997-01-01

    The cause of the long-suspected excessive conservatism in the prevailing structural deterministic safety factor has been identified as an inherent violation of the error propagation laws when reducing statistical data to deterministic values and then combining them algebraically through successive structural computational processes. These errors are restricted to the applied stress computations, and because mean and variations of the tolerance limit format are added, the errors are positive, serially cumulative, and excessively conservative. Reliability methods circumvent these errors and provide more efficient and uniform safe structures. The document is a tutorial on the deficiencies and nature of the current safety factor and of its improvement and transition to absolute reliability.

  2. Inherently safe nuclear-driven internal combustion engines

    International Nuclear Information System (INIS)

    Alesso, P.; Chow, Tze-Show; Condit, R.; Heidrich, J.; Pettibone, J.; Streit, R.

    1991-01-01

    A family of nuclear driven engines is described in which nuclear energy released by fissioning of uranium or plutonium in a prompt critical assembly is used to heat a working gas. Engine performance is modeled using a code that calculates hydrodynamics, fission energy production, and neutron transport self-consistently. Results are given demonstrating a large negative temperature coefficient that produces self-shutoff of energy production. Reduced fission product inventory and the self-shutoff provide inherent nuclear safety. It is expected that nuclear engine reactor units could be scaled from 100 MW on up. 7 refs., 3 figs

  3. Inherent security benefits of underground dry storage of nuclear materials

    International Nuclear Information System (INIS)

    Moore, R.D.; Zahn, T.

    1997-07-01

    This paper, augmented by color slides and handouts, will examine the inherent security benefits of underground dry storage of nuclear materials. Specific items to be presented include: the successful implementation of this type of storage configuration at Argonne National Laboratory - West; facility design concepts with security as a primary consideration; physical barriers achieved by container design; detection, assessment, and monitoring capabilities; and open-quotes self protectionclose quotes strategies. This is a report on the security features of such a facility. The technical operational aspects of the facility are beyond the scope of this paper

  4. Inherent and antigen-induced airway hyperreactivity in NC mice

    OpenAIRE

    Tetsuto Kobayashi; Toru Miura; Tomoko Haba; Miyuki Sato; Masao Takei; Isao Serizawa

    1999-01-01

    In order to clarify the airway physiology of NC mice, the following experiments were carried out. To investigate inherent airway reactivity, we compared tracheal reactivity to various chemical mediators in NC, BALB/c, C57BL/6 and A/J mice in vitro. NC mice showed significantly greater reactivity to acetylcholine than BALB/c and C57BL/6 mice and a reactivity comparable to that of A/J mice, which are known as high responders. Then, airway reactivity to acetylcholine was investigated in those st...

  5. Plants status monitor: Modelling techniques and inherent benefits

    International Nuclear Information System (INIS)

    Breeding, R.J.; Lainoff, S.M.; Rees, D.C.; Prather, W.A.; Fickiessen, K.O.E.

    1987-01-01

    The Plant Status Monitor (PSM) is designed to provide plant personnel with information on the operational status of the plant and compliance with the plant technical specifications. The PSM software evaluates system models using a 'distributed processing' technique in which detailed models of individual systems are processed rather than by evaluating a single, plant-level model. In addition, development of the system models for PSM provides inherent benefits to the plant by forcing detailed reviews of the technical specifications, system design and operating procedures, and plant documentation. (orig.)

  6. The minimum attention plant inherent safety through LWR simplification

    International Nuclear Information System (INIS)

    Turk, R.S.; Matzie, R.A.

    1987-01-01

    The Minimum Attention Plant (MAP) is a unique small LWR that achieves greater inherent safety, improved operability, and reduced costs through design simplification. The MAP is a self-pressurized, indirect-cycle light water reactor with full natural circulation primary coolant flow and multiple once-through steam generators located within the reactor vessel. A fundamental tenent of the MAP design is its complete reliance on existing LWR technology. This reliance on conventional technology provides an extensive experience base which gives confidence in judging the safety and performance aspects of the design

  7. Inherent overload protection for the series resonant converter

    Science.gov (United States)

    King, R. J.; Stuart, T. A.

    1983-01-01

    The overload characteristics of the full bridge series resonant power converter are considered. This includes analyses of the two most common control methods presently in use. The first of these uses a current zero crossing detector to synchronize the control signals and is referred to as the alpha controller. The second is driven by a voltage controlled oscillator and is referred to as the gamma controller. It is shown that the gamma controller has certain reliability advantages in that it can be designed with inherent short circuit protection. Experimental results are included for an 86 kHz converter using power metal-oxide-semiconductor field-effect transistors (MOSFETs).

  8. Inherent uncertainties in meteorological parameters for wind turbine design

    Science.gov (United States)

    Doran, J. C.

    1982-01-01

    Major difficulties associated with meteorological measurments such as the inability to duplicate the experimental conditions from one day to the next are discussed. This lack of consistency is compounded by the stochastic nature of many of the meteorological variables of interest. Moreover, simple relationships derived in one location may be significantly altered by topographical or synoptic differences encountered at another. The effect of such factors is a degree of inherent uncertainty if an attempt is made to describe the atmosphere in terms of universal laws. Some of these uncertainties and their causes are examined, examples are presented and some implications for wind turbine design are suggested.

  9. Using the SEE-SEP Model to Analyze Upper Secondary Students' Use of Supporting Reasons in Arguing Socioscientific Issues

    Science.gov (United States)

    Christenson, Nina; Chang Rundgren, Shu-Nu; Hoglund, Hans-Olof

    2012-01-01

    To achieve the goal of scientific literacy, the skills of argumentation have been emphasized in science education during the past decades. But the extent to which students can apply scientific knowledge to their argumentation is still unclear. The purpose of this study was to analyse 80 Swedish upper secondary students' informal argumentation on…

  10. Scepticism and doubt in science and science education: the complexity of global warming as a socio-scientific issue

    Science.gov (United States)

    Bryce, Tom G. K.; Day, Stephen P.

    2014-09-01

    This article looks critically at the complexity of the debate among climate scientists; the controversies in the science of global temperature measurement; and at the role played by consensus. It highlights the conflicting perspectives figuring in the mass media concerned with climate change, arguing that science teachers should be familiar with them, particularly given the sharply contested views likely to be brought into classroom discussion and the importance of developing intellectual scepticism and robust scientific literacy in students. We distinguish between rational scepticism and the pejorative meaning of the expression associated with attitudinal opposition to global warming—similar to the way in which Bauer (2006) contrasts micro- scepticism and macro- scepticism in reasoning generally. And we look closely and critically at the approaches which teachers might adopt in practice to teach about global warming at this difficult time.

  11. Changes in Primary Students' Informal Reasoning during an Environment-Related Curriculum on Socio-Scientific Issues

    Science.gov (United States)

    Karpudewan, Mageswary; Roth, Wolff-Michael

    2018-01-01

    Recent studies emphasize the importance of learning science while considering multiple perspectives on environment, society, economy, and technology, which allows learners to relate what they do in the classroom to the world beyond. In this study, 68 12-year-old primary students from 1 Malaysian school were followed while they engaged in a science…

  12. Scepticism and Doubt in Science and Science Education: The Complexity of Global Warming as a Socio-Scientific Issue

    Science.gov (United States)

    Bryce, Tom G. K.; Day, Stephen P.

    2014-01-01

    This article looks critically at the complexity of the debate among climate scientists; the controversies in the science of global temperature measurement; and at the role played by "consensus." It highlights the conflicting perspectives figuring in the mass media concerned with climate change, arguing that science teachers should be…

  13. Using Memes and Memetic Processes to Explain Social and Conceptual Influences on Student Understanding about Complex Socio-Scientific Issues

    Science.gov (United States)

    Yoon, Susan

    2008-01-01

    This study investigated seventh grade learners' decision making about genetic engineering concepts and applications. A social network analyses supported by technology tracked changes in student understanding with a focus on social and conceptual influences. Results indicated that several social and conceptual mechanisms potentially affected how…

  14. Introduction: The Transparency Issue

    NARCIS (Netherlands)

    Teurlings, J.; Stauff, M.

    2014-01-01

    Besides giving an overview on the individual contributions, this introduction to the special issue on transparency delineates a conceptual context for a critical analysis of the contemporary discourse on transparency and the media mechanisms related to it. It focuses on three ambivalences inherent

  15. The inherent inefficiency of simultaneously feasible financial transmission rights auctions

    International Nuclear Information System (INIS)

    Deng, Shi-Jie; Oren, Shmuel; Meliopoulos, A.P.

    2010-01-01

    Empirical evidence from the New York ISO shows that the clearing prices for point-to-point congestion revenue rights, also known as financial transmission rights (FTRs), resulting from centralized auctions conducted by Independent System Operators differ significantly and systematically from the realized congestion revenues that determine the accrued payoffs of these rights. The question addressed by this paper is whether such deviations are due to price discovery errors which will eventually vanish or due to inherent inefficiencies in the auction structure. We show that even with perfect foresight of average congestion rents the clearing prices for the FTRs depend on the bid quantity and therefore may not be priced correctly in the financial transmission right (FTR) auction. In particular, we prove that quantity limits on the FTR bids may cause the auction clearing prices to differ from the bid prices. This phenomenon which is inherent in the theoretical properties of the optimization algorithm used to clear the auction, is further illustrated through numerical simulations with test systems. We conclude that price discovery alone would not remedy the discrepancy between the auction prices and the realized values of the FTRs. Secondary markets or frequent reconfiguration auctions are necessary in order to achieve such convergence. (author)

  16. Basis, evidences and consequences of the inherent stellar encocooning

    CERN Document Server

    Celis, L

    2002-01-01

    Based on 7093 observations with photoelectrical photometrical measurements of 191 Mira stars, the following equations (from the papers [1] to [18]) give the basis to establish the Inherent Stellar Encocooning with the spectro-photometric characteristics of the red giant variable stars, especially the Miras, which have large amplitudes (approx 50% of giant variables). The specific basis that justifies a progressive covering with ionized molecules, cold gases, dust and grains are: The relation of the visual amplitudes A sub v =A sub r +E sub A whose real luminosity separate the intrinsic pulsation and amplitude excess effects due to the presence of molecules [145] and an opaque envelope of cool gases; The relation of the visual absolute magnitudes M sub v =M sub v sub r (P)+M sub a (delta sub T sub i sub O V) which is affected by an inherent absorption and/or occultation, and; The relation that defines the probable absolute luminosity and depends on the period and the (Sa) spectral type at maximum M sub v =-2.2...

  17. Drug policy in sport: hidden assumptions and inherent contradictions.

    Science.gov (United States)

    Smith, Aaron C T; Stewart, Bob

    2008-03-01

    This paper considers the assumptions underpinning the current drugs-in-sport policy arrangements. We examine the assumptions and contradictions inherent in the policy approach, paying particular attention to the evidence that supports different policy arrangements. We find that the current anti-doping policy of the World Anti-Doping Agency (WADA) contains inconsistencies and ambiguities. WADA's policy position is predicated upon four fundamental principles; first, the need for sport to set a good example; secondly, the necessity of ensuring a level playing field; thirdly, the responsibility to protect the health of athletes; and fourthly, the importance of preserving the integrity of sport. A review of the evidence, however, suggests that sport is a problematic institution when it comes to setting a good example for the rest of society. Neither is it clear that sport has an inherent or essential integrity that can only be sustained through regulation. Furthermore, it is doubtful that WADA's anti-doping policy is effective in maintaining a level playing field, or is the best means of protecting the health of athletes. The WADA anti-doping policy is based too heavily on principals of minimising drug use, and gives insufficient weight to the minimisation of drug-related harms. As a result drug-related harms are being poorly managed in sport. We argue that anti-doping policy in sport would benefit from placing greater emphasis on a harm minimisation model.

  18. Inherent and antigen-induced airway hyperreactivity in NC mice

    Directory of Open Access Journals (Sweden)

    Tetsuto Kobayashi

    1999-01-01

    Full Text Available In order to clarify the airway physiology of NC mice, the following experiments were carried out. To investigate inherent airway reactivity, we compared tracheal reactivity to various chemical mediators in NC, BALB/c, C57BL/6 and A/J mice in vitro. NC mice showed significantly greater reactivity to acetylcholine than BALB/c and C57BL/6 mice and a reactivity comparable to that of A/J mice, which are known as high responders. Then, airway reactivity to acetylcholine was investigated in those strains in vivo. NC mice again showed comparable airway reactivity to that seen in A/J mice and a significantly greater reactivity than that seen in BALB/c and C57BL/6 mice. To investigate the effects of airway inflammation on airway reactivity to acetylcholine in vivo, NC and BALB/c mice were sensitized to and challenged with antigen. Sensitization to and challenge with antigen induced accumulation of inflammatory cells, especially eosinophils, in lung and increased airway reactivity in NC and BALB/c mice. These results indicate that NC mice exhibit inherent and antigen-induced airway hyperreactivity. Therefore, NC mice are a suitable strain to use in investigating the mechanisms underlying airway hyperreactivity and such studies will provide beneficial information for understanding the pathophysiology of asthma.

  19. The inherent catastrophic traps in retrograde CTO PCI.

    Science.gov (United States)

    Wu, Eugene B; Tsuchikane, Etsuo

    2018-05-01

    When we learn to drive, our driving instructor tells us how to check the side mirror and turn your head to check the blind spot before changing lanes. He tells us how to stop at stop signs, how to drive in slippery conditions, the safe stopping distances, and these all make our driving safe. Similarly, when we learn PCI, our mentors teach us to seat the guiding catheter co-axially, to wire the vessel safely, to deliver balloon and stents over the wire, to watch the pressure of the guiding, in order that we perform PCI safely and evade complications. In retrograde CTO PCI, there is no such published teaching. Also many individual mentors have not had the wide experience to see all the possible complications of retrograde CTO PCI and, therefore, may not be able to warn their apprentice. As the number of retrograde procedures increase worldwide, there is a corresponding increase in catastrophic complications, many of which, we as experts, can see are easily avoidable. To breach this gap in knowledge, this article describes 12 commonly met inherent traps in retrograde CTO PCI. They are inherent because by arranging our equipment in the manner to perform retrograde CTO PCI, these complications are either induced directly or happen easily. We hope this work will enhance safety of retrograde CTO PCI and avoid many catastrophic complications for our readers and operators. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  20. Inherent optical properties of the coccolithophore: Emiliania huxleyi.

    Science.gov (United States)

    Zhai, Peng-Wang; Hu, Yongxiang; Trepte, Charles R; Winker, David M; Josset, Damien B; Lucker, Patricia L; Kattawar, George W

    2013-07-29

    A realistic nonspherical model for Emiliania huxleyi (EHUX) is built, based on electron micrographs of coccolithophore cells. The Inherent Optical Properties (IOP) of the EHUX are then calculated numerically by using the discrete dipole approximation. The coccolithophore model includes a near-spherical core with the refractive index of 1.04 + m(i)j, and a carbonate shell formed by smaller coccoliths with refractive index of 1.2 + m(i)j, where m(i) = 0 or 0.01 and j(2) = -1. The reported IOP are the Mueller scattering matrix, backscattering probability, and depolarization ratio. Our calculation shows that the Mueller matrices of coccolithophores show different angular dependence from those of coccoliths.

  1. Project of a binary breeder reactor and its inherent safety

    International Nuclear Information System (INIS)

    Nascimento, J.A. do; Dias, A.F.; Ishiguro, Y.

    1983-01-01

    A core layout for the binary breeder reactor (BBR) is developed based on the results of preliminary burnup calculations. In the U 233 /TH fueled inner core, the apparent breeding ratio is low due to the accumulation of Pa-233 in the first few months of operation. The loss of reactivity during this time is approximatelly 3%. The BBR requires more reactivity control than Pu/U-fueled LMFBRs and the core layout developed has 19 control rod assemblies in the inner core. Three aspects related to the inherent safety of the BBR have been studied: radial distribution of the sodium-void reactivity, zone-wise Doppler reactivity, and the delayed neutron fractions. Results show excellent safety characteristics of the BBR. (Author) [pt

  2. A simple graphical method for measuring inherent safety

    International Nuclear Information System (INIS)

    Gupta, J.P.; Edwards, David W.

    2003-01-01

    Inherently safer design (ISD) concepts have been with us for over two decades since their elaboration by Kletz [Chem. Ind. 9 (1978) 124]. Interest has really taken off globally since the early nineties after several major mishaps occurred during the eighties (Bhopal, Mexico city, Piper-alfa, Philips Petroleum, to name a few). Academic and industrial research personnel have been actively involved into devising inherently safer ways of production. The regulatory bodies have also shown deep interest since ISD makes the production safer and hence their tasks easier. Research funding has also been forthcoming for new developments as well as for demonstration projects. A natural question that arises is as to how to measure ISD characteristics of a process? Several researchers have worked on this [Trans. IChemE, Process Safety Environ. Protect. B 71 (4) (1993) 252; Inherent safety in process plant design, Ph.D. Thesis, VTT Publication Number 384, Helsinki University of Technology, Espoo, Finland, 1999; Proceedings of the Mary Kay O'Connor Process Safety Center Symposium, 2001, p. 509]. Many of the proposed methods are very elegant, yet too involved for easy adoption by the industry which is scared of yet another safety analysis regime. In a recent survey [Trans. IChemE, Process Safety Environ. Prog. B 80 (2002) 115], companies desired a rather simple method to measure ISD. Simplification is also an important characteristic of ISD. It is therefore desirable to have a simple ISD measurement procedure. The ISD measurement procedure proposed in this paper can be used to differentiate between two or more processes for the same end product. The salient steps are: Consider each of the important parameters affecting the safety (e.g., temperature, pressure, toxicity, flammability, etc.) and the range of possible values these parameters can have for all the process routes under consideration for an end product. Plot these values for each step in each process route and compare. No

  3. Transient behaviour and inherent safety research of LMFBR power plants

    International Nuclear Information System (INIS)

    Zhu Jizhou; Wang Ping; Yu Baoan

    1995-06-01

    Fast Breeder Reactor will be the next generation reactor for nuclear electricity production, the development of FBR will give the profits of efficient utilization of nuclear resources. The fast reactor safety analysis is the foundation and key of FBR research work. Therefore, a block-oriented mathematical model for the primary system of LMFBRs was constructed, and the dynamic simulating results which have been carried out on micro-computer are presented for various transients, i.e. TOP, LOFS, LOHS. The results agree well with the corresponding results of the code NATDEMO and experiment results of EBR-II. Based on previous analysis, various methods are discussed to confirm the inherent safety of LMFBR

  4. Inherent calibration of microdosemeters for dose distributions in lineal energy

    Energy Technology Data Exchange (ETDEWEB)

    Crossman, J.S.P.; Watt, D.E. [Saint Andrews Univ. (United Kingdom). Dept. of Physics and Astronomy

    1994-12-31

    A method, utilising the inherent electron event spectra, is described for the absolute calibration of microdosemeters in the presence of a photon field. The method, which avoids the problems and uncertainties present in conventional calibration techniques, involves simple extrapolation of the dose distribution in lineal energy associated with `exact stopper` electrons. Validation of the method is made using the published experimental distributions of Rossi, of Kliauga, and of Dvorak and by direct theoretical calculation of the components of the microdose distributions for gamma rays. Further experimental data from a cylindrical TEPC in a photon field generated by an external source of {sup 137}Cs are obtained for comparison. A `universal` calibration curve for the dose-weighted lineal energy as a function of the simulated mean diameter of the microdosemeter, is presented for use in practical applications. (author).

  5. Inherent calibration of microdosemeters for dose distributions in lineal energy

    International Nuclear Information System (INIS)

    Crossman, J.S.P.; Watt, D.E.

    1994-01-01

    A method, utilising the inherent electron event spectra, is described for the absolute calibration of microdosemeters in the presence of a photon field. The method, which avoids the problems and uncertainties present in conventional calibration techniques, involves simple extrapolation of the dose distribution in lineal energy associated with 'exact stopper' electrons. Validation of the method is made using the published experimental distributions of Rossi, of Kliauga, and of Dvorak and by direct theoretical calculation of the components of the microdose distributions for gamma rays. Further experimental data from a cylindrical TEPC in a photon field generated by an external source of 137 Cs are obtained for comparison. A 'universal' calibration curve for the dose-weighted lineal energy as a function of the simulated mean diameter of the microdosemeter, is presented for use in practical applications. (author)

  6. Design strategy for control of inherently safe reactors

    International Nuclear Information System (INIS)

    Chisholm, G.H.

    1984-01-01

    Reactor power plant safety is assured through a combination of engineered barriers to radiation release (e.g., reactor containment) in combination with active reactor safety systems to shut the reactor down and remove decay heat. While not specifically identified as safety systems, the control systems responsible for continuous operation of plant subsystems are the first line of defense for mitigating radiation releases and for plant protection. Inherently safe reactors take advantage of passive system features for decay-heat removal and reactor shutdown functions normally ascribed to active reactor safety systems. The advent of these reactors may permit restructuring of the present control system design strategy. This restructuring is based on the fact that authority for protection against unlikely accidents is, as much as practical, placed upon the passive features of the system instead of the traditional placement upon the PPS. Consequently, reactor control may be simplified, allowing the reliability of control systems to be improved and more easily defended

  7. Results of the 1986 FFTF inherent safety tests

    International Nuclear Information System (INIS)

    Burke, T.M.; Campbell, L.R.; Franz, G.R.; Knecht, W.L.

    1987-01-01

    A series of tests was recently completed at the 400-MW (thermal) Fast Flux Test Facility (FFTF) to further demonstrate the passive safety characteristics of liquid-metal-cooled fast reactors. Earlier FFTF testing of decay heat removal by sodium natural circulation was reported in 1981. The main purpose of the 1986 test series was to demonstrate passive reactor shutdown during a loss-of-flow event when several inherent shutdown devices called gas expansion modules (GEMs) were installed in the reactor. However, these tests also provide further data on the natural circulation performance of the primary system, in particular the reactor core, and thus add to the data base available for checking the validity of available analytical tools

  8. Project of a binary breeder reactor and its inherent safety

    International Nuclear Information System (INIS)

    Nascimento, J.A. do; Dias, A.F.; Ishiguro, Y.

    1983-01-01

    A core layout for the binary breeder reactor (BBR) is developed based on the results of preliminary burnup calculations. The apparent breeding ratio, in the U 233 /Th fueled inner core, is low due to the accumulation of Pa-233 in the first few months of operation. The loss of reactivity during this time is around 3%. The BBR requires more reactivity control than Pu/U-fueled LMFBRs and the core layout developed has 19 control rod assemblies in the inner core. Three aspects related to the inherent safety of the Binary Breeder Reactor have been studied: the radial distribution of the sodium-void reactivity zone-wise Doppler reactivity and the fractions of delayed neutrons. The results show excellent characteristics for the BRB safety. (Author) [pt

  9. Contracting for independent evaluation: approaches to an inherent tension.

    Science.gov (United States)

    Klerman, Jacob Alex

    2010-08-01

    There has recently been discussion of whether independent contract evaluation is possible. This article acknowledges the inherent tension in contract evaluation and in response suggests a range of constructive approaches to improving the independence of contract evaluation. In particular, a clear separation between the official evaluation report and a contractor's own publication of analysis from the underlying evaluation appears to be a promising approach. In this approach, the funder would retain almost unfettered rights to the official contract report (including the right never to publish but not the right to change the contractor's text while leaving the contractor's authorship) and the contractor would retain clearly defined rights to publish any findings from the evaluation (subject only to the limitations of human subjects and proprietary data and some minimal notice).

  10. Development of inherent core technologies for advanced reactor

    International Nuclear Information System (INIS)

    Kim, Keung Koo; Noh, J.M.; Hwang, D.H.

    1999-03-01

    Recently, the developed countries made their effort on developing the advanced reactor which will result in significantly enhanced safety and economy. However, they will protect the advanced reactor and its design technology with patent and proprietary right. Therefore, it is very important to develop our own key core concepts and inherent core design technologies which can form a foundation of indigenous technologies for development of the domestic advanced reactor in order to keep the superiority in the nuclear plant building market among the developing countries. In order to provide the basic technology for the core design of advanced reactor, this project is for developing the inherent core design concepts with enhanced safety and economy, and associated methodologies and technologies for core analyses. The feasibility study of constructing domestic critical facilities are performed by surveying the status and utilization of foreign facilities and by investigating the demand for domestic facilities. The research results developed in this project, such as core analysis methodologies for hexagonal core, conceptual core design based on hexagonal fuel assemblies and soluble boron core design and control strategies, will provide a technical foundation in developing core design of domestic advanced reactor. Furthermore, they will strengthen the competitiveness of Korean nuclear technology. We also expect that some of the design concepts developed in this project to improve the reactor safety and economy can be applicable to the design of advanced reactor. This will significantly reduce the public anxiety on the nuclear power plant, and will contribute to the economy of construction and operation for the future domestic reactors. Even though the critical facility will not be constructed right now, the investigation of the status and utilization of foreign critical facility will contribute to the future critical facility construction. (author). 150 refs., 34 tabs., 103

  11. Development of inherent core technologies for advanced reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Keung Koo; Noh, J.M.; Hwang, D.H. [and others

    1999-03-01

    Recently, the developed countries made their effort on developing the advanced reactor which will result in significantly enhanced safety and economy. However, they will protect the advanced reactor and its design technology with patent and proprietary right. Therefore, it is very important to develop our own key core concepts and inherent core design technologies which can form a foundation of indigenous technologies for development of the domestic advanced reactor in order to keep the superiority in the nuclear plant building market among the developing countries. In order to provide the basic technology for the core design of advanced reactor, this project is for developing the inherent core design concepts with enhanced safety and economy, and associated methodologies and technologies for core analyses. The feasibility study of constructing domestic critical facilities are performed by surveying the status and utilization of foreign facilities and by investigating the demand for domestic facilities. The research results developed in this project, such as core analysis methodologies for hexagonal core, conceptual core design based on hexagonal fuel assemblies and soluble boron core design and control strategies, will provide a technical foundation in developing core design of domestic advanced reactor. Furthermore, they will strengthen the competitiveness of Korean nuclear technology. We also expect that some of the design concepts developed in this project to improve the reactor safety and economy can be applicable to the design of advanced reactor. This will significantly reduce the public anxiety on the nuclear power plant, and will contribute to the economy of construction and operation for the future domestic reactors. Even though the critical facility will not be constructed right now, the investigation of the status and utilization of foreign critical facility will contribute to the future critical facility construction. (author). 150 refs., 34 tabs., 103

  12. Inherent Efficiency, Security Markets, and the Pricing of Investments Strategies

    NARCIS (Netherlands)

    Zou, L.; Kin, L.

    2000-01-01

    This paper applies the dichotomous theory of choice by Zou (2000a) tothe analysis of investmentstrategies and security markets. Issues concerning individualoptimality, (approximate) arbitrage,capital market equilibrium, and Pareto efficiency are studied undervarious market conditions. Among the main

  13. Problems in the assessment of inherent safety characteristics of nuclear reactors

    International Nuclear Information System (INIS)

    Garribba, S.F.; Vivante, C.

    1988-01-01

    A number of proposals are being made for an increased RD and D effort on advanced nuclear power reactors that would display outstanding safety performance. A common characteristic of the different reactor concepts would be their limited reliance upon active engineered systems under major accident conditions. However, when submitted to a more close scrutiny reactor concept options may reveal diverging safety behaviors and also development opportunities. In this respect, three issues are explored in this paper. A first question is the meaning of non-active, i.e. inherent and passive safety features. Next, is the ranking of advanced and new reactor concepts from the viewpoint of inherent and passive safety. Multiple correspondence analysis may provide a simple tool, whose use is shown for the case of HTR-500, AP600 and PRISM. Conversely, probabilistic risk assessment would allow quantitative comparisons, although lack of information and data is an obstacle. Finally, is demonstration of safety performances as a step toward market deployment of the new reactor systems

  14. Communicating uncertainty: managing the inherent probabilistic character of hazard estimates

    Science.gov (United States)

    Albarello, Dario

    2013-04-01

    Science is much more fixing the limits of our knowledge about possible occurrences than the identification of any "truth". This is particularly true when scientific statements concern prediction of natural phenomena largely exceeding the laboratory scale as in the case of seismogenesis. In these cases, many scenarios about future occurrences result possible (plausible) and the contribution of scientific knowledge (based on the available knowledge about underlying processes or the phenomenological studies) mainly consists in attributing to each scenario a different level of likelihood (probability). In other terms, scientific predictions in the field of geosciences (hazard assessment) are inherently probabilistic. However, despite of this, many scientist (seismologists, etc.) in communicating their position in public debates tend to stress the " truth" of their statements against the fancy character of pseudo-scientific assertions: stronger is the opposition of science and pseudo-science, more hidden becomes the probabilistic character of scientific statements. The problem arises when this kind of "probabilistic" knowledge becomes the basis of any political action (e.g., to impose expensive form of risk reducing activities): in these cases the lack of any definitive "truth" requires a direct assumption of responsibility by the relevant decider (being the single citizen or the legitimate expression of a larger community) to choose among several possibilities (however characterized by different levels of likelihood). In many cases, this can be uncomfortable and strong is the attitude to delegate to the scientific counterpart the responsibility of these decisions. This "transfer" from the genuine political field to an improper scientific context is also facilitated by the lack of a diffuse culture of "probability" outside the scientific community (and in many cases inside also). This is partially the effect of the generalized adoption (by media and scientific

  15. Experimental quantum control landscapes: Inherent monotonicity and artificial structure

    International Nuclear Information System (INIS)

    Roslund, Jonathan; Rabitz, Herschel

    2009-01-01

    Unconstrained searches over quantum control landscapes are theoretically predicted to generally exhibit trap-free monotonic behavior. This paper makes an explicit experimental demonstration of this intrinsic monotonicity for two controlled quantum systems: frequency unfiltered and filtered second-harmonic generation (SHG). For unfiltered SHG, the landscape is randomly sampled and interpolation of the data is found to be devoid of landscape traps up to the level of data noise. In the case of narrow-band-filtered SHG, trajectories are taken on the landscape to reveal a lack of traps. Although the filtered SHG landscape is trap free, it exhibits a rich local structure. A perturbation analysis around the top of these landscapes provides a basis to understand their topology. Despite the inherent trap-free nature of the landscapes, practical constraints placed on the controls can lead to the appearance of artificial structure arising from the resultant forced sampling of the landscape. This circumstance and the likely lack of knowledge about the detailed local landscape structure in most quantum control applications suggests that the a priori identification of globally successful (un)constrained curvilinear control variables may be a challenging task.

  16. Performance improvement CME for quality: challenges inherent to the process.

    Science.gov (United States)

    Vakani, Farhan Saeed; O'Beirne, Ronan

    2015-01-01

    The purpose of this paper is to discuss the perspective debates upon the real-time challenges for a three-staged Performance Improvement Continuing Medical Education (PI-CME) model, an innovative and potential approach for future CME, to inform providers to think, prepare and to act proactively. In this discussion, the challenges associated for adopting the American Medical Association's three-staged PI-CME model are reported. Not many institutions in USA are using a three-staged performance improvement model and then customizing it to their own healthcare context for the specific targeted audience. They integrate traditional CME methods with performance and quality initiatives, and linking with CME credits. Overall the US health system is interested in a structured PI-CME model with the potential to improve physicians practicing behaviors. Knowing the dearth of evidence for applying this structured performance improvement methodology into the design of CME activities, and the lack of clarity on challenges inherent to the process that learners and providers encounter. This paper establishes all-important first step to render the set of challenges for a three-staged PI-CME model.

  17. Conceptual design of Inherently Safe Fast Reactor (ISFR)

    International Nuclear Information System (INIS)

    Asahi, Yoshiro

    2003-01-01

    ISFR is a boiling heavy water fast reactor of process inherent ultimate safety (PIUS) type. ISFR may breed fuel in the core. Owing to a positive void coefficient, the application of the PIUS concept to ISFR is not straightforward. Thus, the gap conductance is small so that the time constant τ α of the positive void feedback process is sufficiently large, while the initially-closed two-way check valves to be used as passive switches to the pumps are installed at the lower honeycombs. As a result, the passive shutdown mechanisms can come into effect sufficiently soon to suppress the positive feedback reactivity. Both large τ α and the passive switches also help stabilize the system so that ISFR can perform a constant power operation with a simple control logic for the main coolant pump speed. In a steam generator tube rupture, fuel temperature was found to smoothly decrease to the decay heat level with nucleate boiling. The feasibility of ISFR was proved only to some extent. (author)

  18. Demonstration of inherent safety features of HTGRs using the HTTR

    International Nuclear Information System (INIS)

    Tachibana, Yukio; Nakagawa, Shigeaki; Nakazawa, Toshio; Iyoku, Tatsuo

    2004-01-01

    Safety demonstration tests using the High Temperature Engineering Test Reactor (HTTR) are conducted for the purpose of demonstrating inherent safety features of High Temperature Gas-cooled Reactors (HTGRs) quantitatively as well as providing the core and plant transient data for validation of HTGR analysis codes for safety evaluation. The safety demonstration test are divided to the first phase and second phase tests. In the first phase tests, simulation tests of anticipated operational occurrences and anticipated transients without scram (ATWS) are conducted. The second phase tests will simulate accidents such as a depressurization accident (loss of coolant accident). The first phase test simulating reactivity insertion events and coolant flow reduction events stared in FY 2002. Post-test analyses have been conducted to reproduced the test results by using the core and plant dynamics analysis code, ACCORD and Monte Carlo code, MVP. The analysis results agreed fairly well with the test results of a control rod withdrawal test simulating reactivity insertion, and gas circulators trip test simulating coolant flow reduction, at power levels of 50% and 30% of the rated power, respectively. It is shown that improvement of the ACCORD code by taking into consideration vertical and horizontal temperature distribution gives better analysis results in the control rod withdrawal test. The fist phase safety demonstration tests will continue until FY 2005, and the second phase tests are planned to be started in FY 2006. (author)

  19. Accounting for inherent variability of growth in microbial risk assessment.

    Science.gov (United States)

    Marks, H M; Coleman, M E

    2005-04-15

    Risk assessments of pathogens need to account for the growth of small number of cells under varying conditions. In order to determine the possible risks that occur when there are small numbers of cells, stochastic models of growth are needed that would capture the distribution of the number of cells over replicate trials of the same scenario or environmental conditions. This paper provides a simple stochastic growth model, accounting only for inherent cell-growth variability, assuming constant growth kinetic parameters, for an initial, small, numbers of cells assumed to be transforming from a stationary to an exponential phase. Two, basic, microbial sets of assumptions are considered: serial, where it is assume that cells transform through a lag phase before entering the exponential phase of growth; and parallel, where it is assumed that lag and exponential phases develop in parallel. The model is based on, first determining the distribution of the time when growth commences, and then modelling the conditional distribution of the number of cells. For the latter distribution, it is found that a Weibull distribution provides a simple approximation to the conditional distribution of the relative growth, so that the model developed in this paper can be easily implemented in risk assessments using commercial software packages.

  20. Inherent aerobic capacity-dependent differences in breast carcinogenesis.

    Science.gov (United States)

    Thompson, Henry J; Jones, Lee W; Koch, Lauren G; Britton, Steven L; Neil, Elizabeth S; McGinley, John N

    2017-09-01

    Although regular physical activity is associated with improvement in aerobic capacity and lower breast cancer risk, there are heritable sets of traits that affect improvement in aerobic capacity in response to physical activity. Although aerobic capacity segregates risk for a number of chronic diseases, the effect of the heritable component on cancer risk has not been evaluated. Therefore, we investigated breast carcinogenesis in rodent models of heritable fitness in the absence of induced physical activity. Female offspring of N:NIH rats selectively bred for low (LIAC) or high (HIAC) inherent aerobic capacity were injected intraperitoneally with 1-methyl-1-nitrosurea (70 mg/kg body wt). At study termination 33 weeks post-carcinogen, cancer incidence (14.0 versus 47.3%; P < 0.001) and multiplicity (0.18 versus 0.85 cancers per rat; P < 0.0001) were significantly decreased in HIAC versus LIAC rats, respectively. HIAC had smaller visceral and subcutaneous body fat depots than LIAC and activity of two proteins that regulated the mammalian target of rapamycin, protein kinase B (Akt), and adenosine monophosphate-activated protein kinase were suppressed and activated, respectively, in HIAC. Although many factors distinguish between HIAC and LIAC, it appears that the protective effect of HIAC against breast carcinogenesis is mediated, at least in part, via alterations in core metabolic signaling pathways deregulated in the majority of human breast cancers. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Tumor inherent interferons: Impact on immune reactivity and immunotherapy.

    Science.gov (United States)

    Brockwell, Natasha K; Parker, Belinda S

    2018-04-19

    Immunotherapy has revolutionized cancer treatment, with sustained responses to immune checkpoint inhibitors reported in a number of malignancies. Such therapeutics are now being trialed in aggressive or advanced cancers that are heavily reliant on untargeted therapies, such as triple negative breast cancer. However, responses have been underwhelming to date and are very difficult to predict, leading to an inability to accurately weigh up the benefit-to-risk ratio for their implementation. The tumor immune microenvironment has been closely linked to immunotherapeutic response, with superior responses observed in patients with T cell-inflamed or 'hot' tumors. One class of cytokines, the type I interferons, are a major dictator of tumor immune infiltration and activation. Tumor cell inherent interferon signaling dramatically influences the immune microenvironment and the expression of immune checkpoint proteins, hence regulators and targets of this pathway are candidate biomarkers of immunotherapeutic response. In support of a link between IFN signaling and immunotherapeutic response, the combination of type I interferon inducers with checkpoint immunotherapy has recently been demonstrated critical for a sustained anti-tumor response in aggressive breast cancer models. Here we review evidence that links type I interferons with a hot tumor immune microenvironment, response to checkpoint inhibitors and reduced risk of metastasis that supports their use as biomarkers and therapeutics in oncology. Copyright © 2018. Published by Elsevier Ltd.

  2. Inherent Difference in Saliency for Generators with Different PM Materials

    Directory of Open Access Journals (Sweden)

    Sandra Eriksson

    2014-01-01

    Full Text Available The inherent differences between salient and nonsalient electrical machines are evaluated for two permanent magnet generators with different configurations. The neodymium based (NdFeB permanent magnets (PMs in a generator are substituted with ferrite magnets and the characteristics of the NdFeB generator and the ferrite generator are compared through FEM simulations. The NdFeB generator is a nonsalient generator, whereas the ferrite machine is a salient-pole generator, with small saliency. The two generators have almost identical properties at rated load operation. However, at overload the behaviour differs between the two generators. The salient-pole, ferrite generator has lower maximum torque than the NdFeB generator and a larger voltage drop at high current. It is concluded that, for applications where overload capability is important, saliency must be considered and the generator design adapted according to the behaviour at overload operation. Furthermore, if the maximum torque is the design criteria, additional PM mass will be required for the salient-pole machine.

  3. Inherent variation in multiple shoe-sole test impressions.

    Science.gov (United States)

    Shor, Yaron; Wiesner, Sarena; Tsach, Tsadok; Gurel, Ron; Yekutieli, Yoram

    2018-04-01

    Shoeprints left at crime scenes are seldom perfect. Many prints are distorted or contaminated by various materials. Noisy background often contributes to vagueness on the shoeprints as well. Test impressions made from the suspect's shoes in the laboratory are considered a genuine replication of the shoe-sole. This naïve attitude is far from being correct. Consecutive test impressions made in the laboratory under strict similar conditions revealed differences among the exemplars of the same sole. Some of them are minor, but some are major, and can mislead the less experienced practitioners during the comparison process. This article focuses on the inherent within source variability between controlled shoeprints made from the same shoe, as it appears on the RACs. To describe and analyze this variability, repeated test impressions were prepared, and datasets were created. Several RACs were marked on each test impression, using an expert assisting software tool (developed in the authors' lab). The variance in repeated test impressions is demonstrated and possible sources are discussed. This variance should be considered when trying to establish the degree of matching between individual characteristics. Copyright © 2017. Published by Elsevier B.V.

  4. Metal-fuel modeling for inherently safe reactor designs

    International Nuclear Information System (INIS)

    Miles, K.J. Jr.

    1987-01-01

    Current development of breeder reactor systems has led to the renewed interest in metal fuels. These fuels have properties that enhance the inherent safety of the system, such as high thermal conductivity, compatibility with liquid sodium, and low fuel/cladding mechanical interaction. While metal-fuel irradiation behavior is well understood, there are some areas where more information is needed to fully understand the various safety-related phenomena, such as fuel/cladding chemical interaction, eutectic melting and penetration, and axial relocation of molten fuel prior to cladding breach. Because many of these phenomena can cause changes in the reactivity state of the system, their effects on whole-core normal, anticipated, and hypothetical accident scenarios need to be studied. The metal-fuel behavior model DEFORM-5 is being developed to provide the necessary phenomenological basis for these studies. The first stage in the DEFORM-5 development has been completed. Presently, DEFORM-5 calculates the cladding strain, life fraction, and eutectic penetration thinning for Types D9, HT9, or 316 steels. This first stage of DEFORM-5 has been used to analyze the TREAT M2, M3, and M4 transients with irradiated Experimental Breeder Reactor-II driver fuel. The paper shows the DEFORM-5 and experimental results for failure times for the test pins. The results provide confidence and validation of the DEFORM-5 modeling of the cladding behavior

  5. Managing inherent complexity for sustainable walleye fisheries in Lake Erie

    Science.gov (United States)

    Roseman, Edward F.; Drouin, Richard; Gaden, Marc; Knight, Roger; Tyson, Jeff; Zhao, Yingming; Taylor, William W.; Lynch, Abigail J.; Léonard, Nancy J.

    2012-01-01

    In Lake Erie, Walleye (Sander vitreus vitreus) is king. The naturally occurring species is the foundation of commercial fishing operations on the Canadian side of the lake and is a much-prized sport fish on the American side. Management of Lake Erie walleye fisheries is complex and takes place in an inter-jurisdictional setting composed of resource agencies from the states of Michigan (MDNR), Ohio (ODNR), Pennsylvania (PFBC), and New York (NYDEC) and the province of Ontario (OMNR). The complexity of walleye management is exacerbated by interactions among environmental and ecological changes in Lake Erie, complex life-history characteristics of the species, public demand for walleye, and cultural/governance differences among managing groups and their respective constituents. Success of future management strategies will largely hinge upon our ability to understand these inherent complexities and to employ tactics that successfully accommodate stock productivity and human demand in a highly dynamic environment. In this report, we review the history of Lake Erie walleye management, outline the multi-jurisdictional process for international management of walleye, and discuss strategies to address challenges facing managers.

  6. On the fundamentals of nuclear reactor safety assessment. Inherent threats and their implications

    Energy Technology Data Exchange (ETDEWEB)

    Hyvaerinen, J. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland). Nuclear Safety Dept.

    1996-12-01

    The thesis addresses some fundamental questions related to implementation and assessment of nuclear safety. The safety principles and assessment methods are described, followed by descriptions of selected novel technical challenges to nuclear safety. The novel challenges encompass a wide variety of technical issues, thus providing insights on the limitations of conventional safety assessment methods. Study of the limitations suggests means to improve nuclear reactor design criteria and safety assessment practices. The novel safety challenges discussed are (1) inherent boron dilution in PWRs, (2) metallic insulation performance with respect to total loss of emergency cooling systems in a loss-of-coolant accident, and (3) horizontal steam generator heat transfer performance at natural circulation conditions. (50 refs.).

  7. On the fundamentals of nuclear reactor safety assessment. Inherent threats and their implications

    International Nuclear Information System (INIS)

    Hyvaerinen, J.

    1996-12-01

    The thesis addresses some fundamental questions related to implementation and assessment of nuclear safety. The safety principles and assessment methods are described, followed by descriptions of selected novel technical challenges to nuclear safety. The novel challenges encompass a wide variety of technical issues, thus providing insights on the limitations of conventional safety assessment methods. Study of the limitations suggests means to improve nuclear reactor design criteria and safety assessment practices. The novel safety challenges discussed are (1) inherent boron dilution in PWRs, (2) metallic insulation performance with respect to total loss of emergency cooling systems in a loss-of-coolant accident, and (3) horizontal steam generator heat transfer performance at natural circulation conditions. (50 refs.)

  8. Inherent risk and organisational design in European tort law

    NARCIS (Netherlands)

    W.H. van Boom (Willem)

    2009-01-01

    textabstractThis paper is devoted to a complex set of issues relating to the functions of tort law in distinguishing acceptable and unacceptable risks. Often, such risks are brought about by deliberate organisational design choice. On many occasions, legislators and courts are called upon to assess

  9. Thermally responsive polymer electrolytes for inherently safe electrochemical energy storage

    Science.gov (United States)

    Kelly, Jesse C.

    Electrochemical double layer capacitors (EDLCs), supercapacitors and Li-ion batteries have emerged as premier candidates to meet the rising demands in energy storage; however, such systems are limited by thermal hazards, thermal runaway, fires and explosions, all of which become increasingly more dangerous in large-format devices. To prevent such scenarios, thermally-responsive polymer electrolytes (RPEs) that alter properties in electrochemical energy storage devices were designed and tested. These RPEs will be used to limit or halt device operation when temperatures increase beyond a predetermined threshold, therefore limiting further heating. The development of these responsive systems will offer an inherent safety mechanism in electrochemical energy storage devices, while preserving the performance, lifetimes, and versatility that large-format systems require. Initial work focused on the development of a model system that demonstrated the concept of RPEs in an electrochemical device. Aqueous electrolyte solutions of polymers exhibiting properties that change in response to temperature were developed for applications in EDLCs and supercapacitors. These "smart materials" provide a means to control electrochemical systems where polymer phase separation at high temperatures affects electrolyte properties and inhibits device performance. Aqueous RPEs were synthesized using N-isopropylacrylamide, which governs the thermal properties, and fractions of acrylic acid or vinyl sulfonic acids, which provide ions to the solution. The molecular properties of these aqueous RPEs, specifically the ionic composition, were shown to influence the temperature-dependent electrolyte properties and the extent to which these electrolytes control the energy storage characteristics of a supercapacitor device. Materials with high ionic content provided the highest room temperature conductivity and electrochemical activity; however, RPEs with low ionic content provided the highest "on

  10. Large Eddy Simulation for an inherent boron dilution transient

    International Nuclear Information System (INIS)

    Jayaraju, S.T.; Sathiah, P.; Komen, E.M.J.; Baglietto, E.

    2013-01-01

    Highlights: • Large Eddy Simulation is performed for a transient boron dilution scenario in the scaled experimental facility of ROCOM. • Fully conformal polyhedral grid of 14 million is created to capture all details of the domain. • Systematic multi-step validation methodology is followed to assess the accuracy of LES model. • For the presently simulated BDT scenario, the LES results lend support to its reliability in consistently predicting the slug transport in the RPV. -- Abstract: The present paper focuses on the validation and applicability of large eddy simulation (LES) to analyze the transport and mixing in the reactor pressure vessel (RPV) during an inherent boron dilution transient (BDT) scenario. Extensive validation data comes from relevant integral tests performed in the scaled ROCOM experimental facility. The modeling of sub-grid-scales is based on the WALE model. A fully conformal polyhedral grid of about 15 million cells is constructed to capture all details in the domain, including the complex structures of the lower-plenum. Detailed qualitative and quantitative validations are performed by following a systematic multi-step validation methodology. Qualitative comparisons to the experimental data in the cold legs, downcomer and the core inlet showed good predictions by the LES model. Minor deviations seen in the quantitative comparisons are rigorously quantified. A key parameter which is affecting the core neutron kinetics response is the value of highest deborated slug concentration that occurs at the core inlet during the transient. Detailed analyses are made at the core inlet to evaluate not only the value of the maximum slug concentration, but also the location and the time at which it occurs during the transient. The relative differences between the ensemble averaged experimental data and CFD predictions were within the range of relative differences seen within 10 different experimental realizations. For the studied scenario, the

  11. An inherently parallel method for solving discretized diffusion equations

    International Nuclear Information System (INIS)

    Eccleston, B.R.; Palmer, T.S.

    1999-01-01

    A Monte Carlo approach to solving linear systems of equations is being investigated in the context of the solution of discretized diffusion equations. While the technique was originally devised decades ago, changes in computer architectures (namely, massively parallel machines) have driven the authors to revisit this technique. There are a number of potential advantages to this approach: (1) Analog Monte Carlo techniques are inherently parallel; this is not necessarily true to today's more advanced linear equation solvers (multigrid, conjugate gradient, etc.); (2) Some forms of this technique are adaptive in that they allow the user to specify locations in the problem where resolution is of particular importance and to concentrate the work at those locations; and (3) These techniques permit the solution of very large systems of equations in that matrix elements need not be stored. The user could trade calculational speed for storage if elements of the matrix are calculated on the fly. The goal of this study is to compare the parallel performance of Monte Carlo linear solvers to that of a more traditional parallelized linear solver. The authors observe the linear speedup that they expect from the Monte Carlo algorithm, given that there is no domain decomposition to cause significant communication overhead. Overall, PETSc outperforms the Monte Carlo solver for the test problem. The PETSc parallel performance improves with larger numbers of unknowns for a given number of processors. Parallel performance of the Monte Carlo technique is independent of the size of the matrix and the number of processes. They are investigating modifications to the scheme to accommodate matrix problems with positive off-diagonal elements. They are also currently coding an on-the-fly version of the algorithm to investigate the solution of very large linear systems

  12. Inherent Reward and Risk (Part I): Towards a Universal Paradigm for Investment Analysis

    OpenAIRE

    Liang Zou

    2000-01-01

    In this paper, a new paradigm is developed for analyzinginvestment strategies and pricing financial assets. This paradigmassumes that any investment strategy has its own “inherent reward”and “inherent risk” that can be judged with common sense. Ijustify axiomatically the existence and uniqueness (ratio scale)of inherent reward (U) and inherent risk (D) that could beregarded as universal measures of reward and risk for any giveninvestment strategy. Incorporating the notion of “inherentefficien...

  13. Is it about "pink" or about "girls"? The inherence heuristic across social and nonsocial domains.

    Science.gov (United States)

    Kinzler, Katherine D; Sullivan, Kathleen R

    2014-10-01

    The inherence heuristic provides an intriguing and novel explanation for early thought in a variety of domains. Exploring similarities and differences in inherent reasoning across social and nonsocial domains can help us understand the role that inherent thinking plays in the development of human reasoning and the process by which more elaborate essentialist reasoning develops.

  14. Chemical looping combustion. Fuel conversion with inherent CO2 capture

    Energy Technology Data Exchange (ETDEWEB)

    Brandvoll, Oeyvind

    2005-07-01

    ONiAl do not rule out CLC as a viable alternative for CO2 capture, but long term durability studies along with realistic testing of the carrier in a continuous rig is needed to firmly conclude. For comparative purposes a perovskite was synthesized and tested in CLC, under similar conditions as NiONiAl. The results indicate that in a moving bed CLC application, perovskites have inherent disadvantages as compared to simpler compounds, by virtue of low relative oxygen content. (Author)

  15. Technology which led to the westinghouse inherently safe liquid metal reactor

    International Nuclear Information System (INIS)

    Schmidt, J.E.; Coffield, R.D.; Doncals, R.A.; Kalinowski, J.E.; Markley, R.A.

    1985-01-01

    The Fast Flux Test Facility (FFTF) and the Clinch River Breeder Reactor programs resulted in an understanding of liquid metal reactor behavior that is being used to design inherent safety capability into liquid metal reactors. Technological advances give the same beneficial operating characteristics of conventional liquid metal reactors, however, the addition of inherently safe design features precludes the initiation of hypothetical core disruptive accidents. These innovative features permit inherent safety capability to be demonstrated with more than adequate margins. Also, the variety of inherent safety features provides the designers with options in selecting inherent design features for a specific reactor application

  16. Inherent risks associated with manufacture of bioengineered ocular surface tissue.

    Science.gov (United States)

    Schwab, Ivan R; Johnson, Nigel T; Harkin, Damien G

    2006-12-01

    To review the potential health risks associated with bioengineered ocular surface tissue, which serves as a bellwether for other tissues. All clinical trials using bioengineered ocular surface tissue published between July 1, 1996, and June 30, 2005, were reviewed with respect to materials used and statements of risk assessment, risk remediation, adverse events, manufacturing standards, and regulatory oversight. Ninety-five percent of investigational protocols used 1 or more animal-derived products and an overlapping 95% used 1 or more donor human tissues. Consideration of risks reveals a very low probability of potential harm but a significant risk of disability or death if such an event were to occur. Details of ethics approval, patient consent, and donor serologic test results were not consistently provided. No references were made to risk assessment or to codes of manufacturing and clinical practice. While a degree of risk is associated with bioengineered ocular surface tissue, investigational reports of this new technology have yet to address issues of risk management and regulatory oversight. Attention to risk and codes of manufacturing and clinical practice will be required for advancement of the technology. We suggest the adoption of international standards to address these issues.

  17. Perspectives on learning through research on critical issues-based science center exhibitions

    Science.gov (United States)

    Pedretti, Erminia G.

    2004-07-01

    Recently, science centers have created issues-based exhibitions as a way of communicating socioscientific subject matter to the public. Research in the last decade has investigated how critical issues-based installations promote more robust views of science, while creating effective learning environments for teaching and learning about science. The focus of this paper is to explore research conducted over a 10-year period that informs our understanding of the nature of learning through these experiences. Two specific exhibitions - Mine Games and A Question of Truth - provide the context for discussing this research. Findings suggest that critical issues-based installations challenge visitors in different ways - intellectually and emotionally. They provide experiences beyond usual phenomenon-based exhibitions and carry the potential to enhance learning by personalizing subject matter, evoking emotion, stimulating dialogue and debate, and promoting reflexivity. Critical issues-based exhibitions serve as excellent environments in which to explore the nature of learning in these nonschool settings.

  18. Understanding the Spatiotemporal Variability of Inherent Water Use Efficiency

    Science.gov (United States)

    Boese, Sven; Jung, Martin; Carvalhais, Nuno; Reichstein, Markus

    2015-04-01

    The global carbon and water cycles are coupled via plant physiology. However, the resulting spatial and temporal covariability of both fluxes on a global scale lacks sufficient understanding. This is required to estimate the impact of atmospheric drought on photosynthesis in water-limited ecosystems. Water use efficiency (WUE) is an essential ecosystem diagnostic defined as the ratio between gross primary productivity (GPP) and transpiration (T). WUE is known to vary with vapour-pressure deficit (VPD) and therefore also in time. The inherent water use efficiency (iWUE) accounts for the VPD effect on WUE and aims at representing a largely time-invariant ecosystem property. However, different ways of describing the functional response of iWUE to VPD are found in the literature. One established iWUE definition was proposed by Beer et al. (2009) and takes the form of iWUE = GPP--VPD- . T (1) A similar definition can be derived from stomatal conductance theories such as Katul et al. (2010) and takes the form of √ -- GPP---VPD- iWUE = T . (2) Here, we use eddy covariance measurements from the FLUXNET database to evaluate both approaches for a globally representative set of biomes including tropical, temperate and semi-arid ecosystems. Testing both definitions in a model-data fusion setup indicated that (2) is more consistent with FLUXNET observations than (1). However, there still remains considerable temporal variability of iWUE which is linked to seasonal changes in VPD. To explore up to which extent the temporal variability of iWUE may be related to the prescribed functional responses to VPD, we treated the exponent of VPD as a global parameter, here termed γ. When γ = 1 the functional response is equivalent to (1), while when γ = 0.5 it corresponds to formulation of model (2)). The global estimate was found to be significantly lower than 0.5, which would have been expected from stomatal conductance theory at leaf level. We assessed whether adding γ as site

  19. Validating safeguards effectiveness given inherently limited test data

    International Nuclear Information System (INIS)

    Sicherman, A.

    1987-01-01

    A key issue in designing and evaluating nuclear safeguards systems is how to validate safeguards effectiveness against a spectrum of potential threats. Safeguards effectiveness is measured by a performance indicator such as the probability of defeating an adversary attempting a malevolent act. Effectiveness validation means a testing program that provides sufficient evidence that the performance indicator is at an acceptable level. Traditional statistical program when numerous independent system trials are possible. However, within the safeguards environment, many situations arise for which traditional statistical approaches may be neither feasible nor appropriate. Such situations can occur, for example, when there are obvious constraints on the number of possible tests due to operational impacts and testing costs. Furthermore, these tests are usually simulations (e.g., staged force-on-force exercises) rather than actual tests, and the system is often modified after each test. Under such circumstances, it is difficult to make and justify inferences about system performance by using traditional statistical techniques. In this paper, the authors discuss several alternative quantitative techniques for validating system effectiveness. The techniques include: (1) minimizing the number of required tests using sequential testing; (2) combining data from models inspections and exercises using Bayesian statistics to improve inferences about system performance; and (3) using reliability growth and scenario modeling to help specify which safeguards elements and scenarios to test

  20. The inherent advantages of delayed dismantling of decommissioning nuclear stations

    International Nuclear Information System (INIS)

    Liederman, J.M.; Saroudis, J.I.

    1985-01-01

    Recent studies in Canada pertaining to the decommissioning of the CANDU 600 MW(e) reactor have led to the development of the option of a ''static state'' condition. This alternative is based on judging risk and benefit to society considering the greatly reduced potential radiation exposure to personnel after 30 to 80 years have elapsed, following the final shutdown of the reactor. After approximately 80 to 120 years have elapsed, the decay in all systems and components (with the exception of the reactor assembly) would be such that radiation fields would be at background levels producing an environment that would be acceptable for Stage 3 decommissiong. This philosophy is based on the current engineering judgement that: - All systems, components, and structures which were associated with the nuclear processes and are radioactive, can be put into a static or storage state, and a containment function maintained at low cost for prolonged periods of between 80 to 120 years. - Between 80 to 120 years after shutdown, most of the radioactivity, except for some long lived radionuclides in the reactor vessel itself and its vault, will have naturally decayed to near releasable limits without any external intervention. - There is a lower overall risk to society in this approach, than dismantling and transporting radioactive materials prematurely. This philosophy is developed taking into consideration radiation protection, financial and risk assessment issues. The Canadian concept of dry storage of spent fuel is part of this philosophy and may be of interest to decommissioned nuclear plants of other types. 4 tables, 5 graphs

  1. Bayesian estimation inherent in a Mexican-hat-type neural network

    Science.gov (United States)

    Takiyama, Ken

    2016-05-01

    Brain functions, such as perception, motor control and learning, and decision making, have been explained based on a Bayesian framework, i.e., to decrease the effects of noise inherent in the human nervous system or external environment, our brain integrates sensory and a priori information in a Bayesian optimal manner. However, it remains unclear how Bayesian computations are implemented in the brain. Herein, I address this issue by analyzing a Mexican-hat-type neural network, which was used as a model of the visual cortex, motor cortex, and prefrontal cortex. I analytically demonstrate that the dynamics of an order parameter in the model corresponds exactly to a variational inference of a linear Gaussian state-space model, a Bayesian estimation, when the strength of recurrent synaptic connectivity is appropriately stronger than that of an external stimulus, a plausible condition in the brain. This exact correspondence can reveal the relationship between the parameters in the Bayesian estimation and those in the neural network, providing insight for understanding brain functions.

  2. Conservatism inherent to simplified qualification techniques used for piping steady state vibration

    International Nuclear Information System (INIS)

    Olson, D.E.; Smetters, J.L.

    1983-01-01

    This paper examines some of the qualification techniques currently used by the power industry, including the techniques specified in a recently issued standard related to this subject (ANSI/ASME OM-3, Requirements for Preoperational and Initial Startup Vibration Testing of Nuclear Power Plant Piping Systems). Several methods are used to demonstrate the amount of conservatism inherent in these techniques. Allowable limits calculated by the use of simplified techniques are compared to limits calculated by more detailed computer analysis. A portion of a reactor feedwater piping system along with the results of a piping vibration monitoring program recently completed in a nuclear power plant are used as case studies. The limits determined by the use of simplified criteria are also compared to limits determined empirically through the use of strain gauges. The simple beam analogies that use vibrational displacement as acceptance criteria were found to be conservative for all the examples studied. However, when velocity was used as a criterion, it was not always conservative. Simplified techniques that result in displacement allowables appear to be the most viable method of qualifying piping vibrations. Quantities referred to in the paper are cited in British units throughout. These may be converted to the International System of Units (SI) as follows: 1 foot=0.3048 meter; 1 inch=0.0254 meter=1,000 mils; 1 psi=6,894 pascals; and 1 inch/second=0.0254 meter/second. (orig.)

  3. Congenital short QT syndrome and implantable cardioverter defibrillator treatment: inherent risk for inappropriate shock delivery.

    Science.gov (United States)

    Schimpf, Rainer; Wolpert, Christian; Bianchi, Francesca; Giustetto, Carla; Gaita, Florenzo; Bauersfeld, Urs; Borggrefe, Martin

    2003-12-01

    A congenital short QT interval constitutes a new primary electrical abnormality associated with syncope and/or sudden cardiac death. We report on the initial use of implantable cardioverter defibrillator (ICD) therapy in patients with inherited short QT interval and discuss sensing abnormalities and detection issues. In five consecutive patients from two unrelated European families who had structurally normal hearts, excessively shortened QT intervals, and a strong positive family history of sudden cardiac death, ICDs were placed for primary and secondary prevention. Mean QT intervals were 252 +/- 13 ms (QTc 287 +/- 13 ms). Despite normal sensing behavior during intraoperative and postoperative device testing, 3 of 5 patients experienced inappropriate shock therapies for T wave oversensing 30 +/- 26 days after implantation. Programming lower sensitivities and decay delays prevented further inappropriate discharges. The congenital short QT syndrome constitutes a new clinical entity with an increased risk for sudden cardiac death. Currently, ICD treatment is the only therapeutic option. In patients with short QT interval and implanted ICD, increased risk for inappropriate therapy is inherent due to the detection of short-coupled and prominent T waves. Careful testing of ICD function and adaptation of sensing levels and decay delays without sacrificing correct arrhythmia detection are essential.

  4. Concept of an inherently-safe high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Ohashi, Hirofumi; Sato, Hiroyuki; Tachibana, Yukio; Kunitomi, Kazuhiko; Ogawa, Masuro

    2012-01-01

    As the challenge to ensure no harmful release of radioactive materials at the accidents by deterministic approach instead to satisfy acceptance criteria or safety goal for risk by probabilistic approach, new concept of advanced reactor, an inherently-safe high temperature gas-cooled reactor, is proposed based on the experience of the operation of the actual High Temperature Gas-cooled Reactor (HTGR) in Japan, High Temperature Engineering Test Reactor (HTTR), and the design of the commercial plant (GTHTR300), utilizing the inherent safety features of the HTGR (i.e., safety features based on physical phenomena). The safety design philosophy of the inherently-safe HTGR for the safety analysis of the radiological consequences is determined as the confinement of radioactive materials is assured by only inherent safety features without engineered safety features, AC power or prompt actions by plant personnel if the design extension conditions occur. Inherent safety features to prevent the loss or degradation of the confinement function are identified. It is proposed not to apply the probabilistic approach for the evaluation of the radiological consequences of the accidents in the safety analysis because no inherent safety features fail for the mitigation of the consequences of the accidents. Consequently, there are no event sequences to harmful release of radioactive materials if the design extension conditions occur in the inherently-safe HTGR concept. The concept and future R and D items for the inherently-safe HTGR are described in this paper.

  5. Inherent reward & risk (Part I): Towards a universal paradigm for investment analysis

    NARCIS (Netherlands)

    Zou, L.

    2000-01-01

    In this paper, a new paradigm is developed for analyzinginvestment strategies and pricing financial assets. This paradigmassumes that any investment strategy has its own "inherent reward"and "inherent risk" that can be judged with common sense. Ijustify axiomatically the existence and uniqueness

  6. Ordeals of Chernobyl and the rejustification of the inherently safe reactors

    International Nuclear Information System (INIS)

    Lu, Y.

    1989-01-01

    This paper presents the necessity of developing inherently safe economic reactors (ISERs). Two characteristics which define inherent safety are discussed on the basis of various applications of such a principle in practice. Different design concepts of ISERs are then evaluated and their possible role in the future nuclear program of PRC discussed. A three-stage development strategy of ISERs in PRC is proposed

  7. A case for inherent geometric and geodetic accuracy in remotely sensed VNIR and SWIR imaging products

    Science.gov (United States)

    Driver, J. M.

    1982-01-01

    Significant aberrations can occur in acquired images which, unless compensated on board the spacecraft, can seriously impair throughput and timeliness for typical Earth observation missions. Conceptual compensations options are advanced to enable acquisition of images with inherent geometric and geodetic accuracy. Research needs are identified which, when implemented, can provide inherently accurate images. Agressive pursuit of these research needs is recommended.

  8. Promoting Scientific Thinking and Conceptual Change about Alternative Explanations of Climate Change and Other Controversial Socio-scientific Topics

    Science.gov (United States)

    Lombardi, D.; Sinatra, G. M.

    2013-12-01

    Critical evaluation and plausibility reappraisal of scientific explanations have been underemphasized in many science classrooms (NRC, 2012). Deep science learning demands that students increase their ability to critically evaluate the quality of scientific knowledge, weigh alternative explanations, and explicitly reappraise their plausibility judgments. Therefore, this lack of instruction about critical evaluation and plausibility reappraisal has, in part, contributed to diminished understanding about complex and controversial topics, such as global climate change. The Model-Evidence Link (MEL) diagram (originally developed by researchers at Rutgers University under an NSF-supported project; Chinn & Buckland, 2012) is an instructional scaffold that promotes students to critically evaluate alternative explanations. We recently developed a climate change MEL and found that the students who used the MEL experienced a significant shift in their plausibility judgments toward the scientifically accepted model of human-induced climate change. Using the MEL for instruction also resulted in conceptual change about the causes of global warming that reflected greater understanding of fundamental scientific principles. Furthermore, students sustained this conceptual change six months after MEL instruction (Lombardi, Sinatra, & Nussbaum, 2013). This presentation will discuss recent educational research that supports use of the MEL to promote critical evaluation, plausibility reappraisal, and conceptual change, and also, how the MEL may be particularly effective for learning about global climate change and other socio-scientific topics. Such instruction to develop these fundamental thinking skills (e.g., critical evaluation and plausibility reappraisal) is demanded by both the Next Generation Science Standards (Achieve, 2013) and the Common Core State Standards for English Language Arts and Mathematics (CCSS Initiative-ELA, 2010; CCSS Initiative-Math, 2010), as well as a

  9. Safety assessment in plant layout design using indexing approach: Implementing inherent safety perspective

    International Nuclear Information System (INIS)

    Tugnoli, Alessandro; Khan, Faisal; Amyotte, Paul; Cozzani, Valerio

    2008-01-01

    Layout planning plays a key role in the inherent safety performance of process plants since this design feature controls the possibility of accidental chain-events and the magnitude of possible consequences. A lack of suitable methods to promote the effective implementation of inherent safety in layout design calls for the development of new techniques and methods. In the present paper, a safety assessment approach suitable for layout design in the critical early phase is proposed. The concept of inherent safety is implemented within this safety assessment; the approach is based on an integrated assessment of inherent safety guideword applicability within the constraints typically present in layout design. Application of these guidewords is evaluated along with unit hazards and control devices to quantitatively map the safety performance of different layout options. Moreover, the economic aspects related to safety and inherent safety are evaluated by the method. Specific sub-indices are developed within the integrated safety assessment system to analyze and quantify the hazard related to domino effects. The proposed approach is quick in application, auditable and shares a common framework applicable in other phases of the design lifecycle (e.g. process design). The present work is divided in two parts: Part 1 (current paper) presents the application of inherent safety guidelines in layout design and the index method for safety assessment; Part 2 (accompanying paper) describes the domino hazard sub-index and demonstrates the proposed approach with a case study, thus evidencing the introduction of inherent safety features in layout design

  10. Long range stress correlations in the inherent structures of liquids at rest

    Energy Technology Data Exchange (ETDEWEB)

    Chowdhury, Sadrul; Abraham, Sneha; Hudson, Toby; Harrowell, Peter [School of Chemistry, University of Sydney, Sydney, NSW 2006 (Australia)

    2016-03-28

    Simulation studies of the atomic shear stress in the local potential energy minima (inherent structures) are reported for binary liquid mixtures in 2D and 3D. These inherent structure stresses are fundamental to slow stress relaxation and high viscosity in supercooled liquids. We find that the atomic shear stress in the inherent structures (IS’s) of both liquids at rest exhibits slowly decaying anisotropic correlations. We show that the stress correlations contribute significantly to the variance of the total shear stress of the IS configurations and consider the origins of the anisotropy and spatial extent of the stress correlations.

  11. The role of passive and inherent safety properties in Siemens/KWU nuclear power plants

    International Nuclear Information System (INIS)

    Gremm, O.

    1990-01-01

    In Siemens/KWU Nuclear Power Plants the applied safety concept consist of a well balanced combination of active, passive use well is inherent safety measures. In principle it is not possible to realise a safety concept exclusively with inherent and/or passive safety properties. The respective measures and arguments will be explained in detail in the presentation. In addition the Siemens/KWU safety concept with examples of the role of inherent and passive safety measures will be illustrated. (author). 9 refs, 9 figs

  12. Compact All Solid State Oceanic Inherent Optical Property Sensor, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Light propagation in the sea and the consequent remote sensing signals seen by aircraft and spacecraft is fundamentally governed by the inherent optical properties...

  13. Probabilities of inherent shutdown of unprotected events in innovative liquid metal reactors

    International Nuclear Information System (INIS)

    Mueller, C.J.; Wade, D.C.

    1988-01-01

    The uncertainty in predicting the effectiveness of inherent shutdown in innovative liquid metal cooled reactors with metallic fuel results from three broad contributing areas of uncertainty: (1) the inability to exactly predict the frequency of ATWS events with potential to challenge the safety systems and require inherent shutdown; (2) the approximation of representing all such events by a selected set of ''generic scenarios''; and (3) the inability to exactly calculate the core response to the selected generic scenarios. This paper discusses the work being done to address each of these contributing areas, identifies the design and research approaches being used at Argonne National Laboratory to reducing the key contributions to uncertainties in inherent shutdown, and presents results. The conditional probabilities (given ATWS initiation) of achieving temperatures capable of defeating inherent shutdown are shown to range from /approximately/0.1% to negligible for current designs

  14. Progress on PRISM, an inherently safe, economic, and testable advanced liquid metal reactor

    International Nuclear Information System (INIS)

    Tippets, F.E.; Salerno, L.N.; Boardman, C.E.; Kwant, W.; Murata, R.E.; Snyder, C.R.

    1987-01-01

    This paper reports progress on the design of PRISM (Power Reactor Inherently Safe Module) under the DOE-sponsored innovative reactor program now in its third year at General Electric. The purpose of this program is to develop a design for an inherently safe, reliable, and marketable liquid metal fast reactor power plant. The PRISM design approach includes the following key elements: Compact sodium-cooled pool-type reactor modules that are sized to enable factory fabrication, economical shipment to inland as well as water-side sites, and economical full-scale prototype testing for design certification; Nuclear safety-related envelope limited to the reactor modules and their service systems; Inherent, passive shutdown heat removal for loss-of-cooling events; Inherent, passive reactivity shutdown for failure-to-scram events

  15. Food plant toxicants and safety - Risk assessment and regulation of inherent toxicants in plant foods

    DEFF Research Database (Denmark)

    Essers, A.J.A.; Alink, G.M.; Speijers, G.J.A.

    1998-01-01

    The ADI as a tool for risk management and regulation of food additives and pesticide residues is not readily applicable to inherent food plant toxicants: The margin between actual intake and potentially toxic levels is often small; application of the default uncertainty factors used to derive ADI...... values, particularly when extrapolating from animal data, would prohibit the utilisation of the food, which may have an overall beneficial health effect. Levels of inherent toxicants are difficult to control; their complete removal is not always wanted, due to their function for the plant or for human...... health. The health impact of the inherent toxicant is often modified by factors in the food, e.g. the bioavailability from the matrix and interaction with other inherent constituents. Risk-benefit analysis should be made for different consumption scenarios, without the use of uncertainty factors. Crucial...

  16. Quantification of Inherent Respirable Dust Generation Potential (IRDGP) of South African Coals

    CSIR Research Space (South Africa)

    Phillips, H

    2003-08-01

    Full Text Available Advisory Committee Project Summary Project Title: Inherent Respirable Dust Generation Potential (IRDGP) of South African Coals-SIM020604 Author(s): H.R.Phillips and B. K. Belle Agency: University of Witwatersrand Report Date: July2003... Related Projects: Health 607, Sim 02-06-03 Category: Occupational Health Applied Research Occupational Hygiene Summary Project SIM020604 was formulated to determine the Inherent Respirable Dust Generation Potential (IRDGP) of various South...

  17. Novel OSNR Monitoring Technique in Dense WDM Systems using Inherently Generated CW Monitoring Channels

    DEFF Research Database (Denmark)

    Petersen, Martin Nordal

    2007-01-01

    We present a simple, yet effective OSNR monitoring technique based on an inherent effect in the optical modulator. Highly accurate OSNR monitoring is demonstrated in a 40 Gb/s dense WDM system with 50 GHz channel spacing.......We present a simple, yet effective OSNR monitoring technique based on an inherent effect in the optical modulator. Highly accurate OSNR monitoring is demonstrated in a 40 Gb/s dense WDM system with 50 GHz channel spacing....

  18. [THE CYTOMETRIC TECHNIQUE OF BINDING OF EOSIN-5-MALEIMIDE IN DIAGNOSTIC OF INHERENT SPHEROCYTOSIS].

    Science.gov (United States)

    Kuzminova, J A; Plyasunova, S A; Jogov, V V; Smetanina, N S

    2016-03-01

    The laboratory diagnostic of inherent spherocytosis is based on detection of spherocytes in peripheral blood, decreasing of index of sphericity, decreasing of osmotic resistance of erythrocytes. The new test of diagnostic of hereditary spherocytosis build on molecular defect was developed on the basis of binding extracellular fragments of protein of band 3 with eosin-5-maleimide (EMA-test). The study was carried out to implement comparative analysis of sensitivity and specificity of techniques applied to diagnose inherent spherocytosis. The sampling of 94 patients with various forms of anemias was analyzed All patients were applied complex clinical laboratory examination including analysis of osmotic resistance of erythrocytes, erythrocytometry and EMA-test as specific techniques of diagnostic of inherent spherocytosis. In 51 out of 94 patients (54%) decreasing of values of EMA-test was detected and in 47 patients diagnosis of inherent spherocytosis was confirmed. The standard values of EMA-test were established in 43 patients (46%) and 12 patients out of them with established diagnosis of inherent spherocytosis. Therefore, sensitivity of EMA-test made up to 79% and specificity - 80%. The most sensitive techniques of diagnostic remain osmotic resistance of erythrocytes (91%) and index of sphericity (up to 96%). But the highest specificity in this respect has EMA-test (80%). Nowadays, none of implemented techniques of diagnostic of inherent spherocytosis can be applied as a universal one. The implementation of complex examination is needed for proper diagnostic of disease.

  19. Development of quantitative goals for inherent safety feature design and licensing

    International Nuclear Information System (INIS)

    Kastenberg, W.E.; Apostolakis, G.; Dhir, V.K.; Okrent, D.

    1987-01-01

    There is now considerable interest in the development of advanced fast reactors whose major focus is inherent safety. The achievement of inherent safety can be viewed from several aspects. In the Integral Fast Reactor Concept the approach is to utilize the intrinsic characteristics of pool-type liquid metal fast breeder reactors (LMFBRs) and the properties of metal fuels to integrate a high degree of inherent safety into the design. The PRISM and SAFR concepts focus on other inherent safety features. The reactors discussed above represent a radical departure from existing LWR designs as well as previous LMFBR designs (e.g., CRBRP) which are based, for the most part, on the General Design Criteria found in 10CFR50 Appendix. In view of these parallel developments (advanced reactors exploiting inherent safety and the use of quantitative goals to augment licensing), there appears to be a need to perform research on the development of methods for designing, assessing, and licensing inherent safety features in advanced reactors. The objectives of such research are outlined

  20. Inherent work suit buoyancy distribution: effects on lifejacket self-righting performance.

    Science.gov (United States)

    Barwood, Martin J; Long, Geoffrey M; Lunt, Heather; Tipton, Michael J

    2014-09-01

    Accidental immersion in cold water is an occupational risk. Work suits and life jackets (LJ) should work effectively in combination to keep the airway clear of the water (freeboard) and enable self-righting. We hypothesized that inherent buoyancy, in the suit or LJ, would be beneficial for enabling freeboard, but its distribution may influence LJ self-righting. Six participants consented to complete nine immersions. Suits and LJ tested were: flotation suit (FLOAT; 85 N inherent buoyancy); oilskins 1 (OS-1) and 2 (OS-2), both with no inherent buoyancy; LJs (inherent buoyancy/buoyancy after inflation/total buoyancy), LJ-1 50/150/200 N, LJ-2 0/290/290 N, LJ-3 80/190/270 N. Once dressed, the subject entered an immersion pool where uninflated freeboard, self-righting performance, and inflated freeboard were measured. Data were compared using Friedman's test to the 0.05 alpha level. All suits and LJs enabled uninflated and inflated freeboard, but differences were seen between the suits and LJs. Self-righting was achieved on 43 of 54 occasions, irrespective of suit or LJ. On all occasions that self-righting was not achieved, this occurred in an LJ that included inherent buoyancy (11/54 occasions). Of these 11 failures, 8 occurred (73% of occasions) when the FLOAT suit was being worn. LJs that included inherent buoyancy, that are certified as effective on their own, worked less effectively from the perspective of self-righting in combination with a work suit that also included inherent buoyancy. Equipment that is approved for use in the workplace should be tested in combination to ensure adequate performance in an emergency scenario.

  1. Is the inherent potential of maize roots efficient for soil phosphorus acquisition?

    Science.gov (United States)

    Deng, Yan; Chen, Keru; Teng, Wan; Zhan, Ai; Tong, Yiping; Feng, Gu; Cui, Zhenling; Zhang, Fusuo; Chen, Xinping

    2014-01-01

    Sustainable agriculture requires improved phosphorus (P) management to reduce the overreliance on P fertilization. Despite intensive research of root adaptive mechanisms for improving P acquisition, the inherent potential of roots for efficient P acquisition remains unfulfilled, especially in intensive agriculture, while current P management generally focuses on agronomic and environmental concerns. Here, we investigated how levels of soil P affect the inherent potential of maize (Zea mays L.) roots to obtain P from soil. Responses of root morphology, arbuscular mycorrhizal colonization, and phosphate transporters were characterized and related to agronomic traits in pot and field experiments with soil P supply from deficiency to excess. Critical soil Olsen-P level for maize growth approximated 3.2 mg kg(-1), and the threshold indicating a significant environmental risk was about 15 mg kg(-1), which represented the lower and upper levels of soil P recommended in current P management. However, most root adaptations involved with P acquisition were triggered when soil Olsen-P was below 10 mg kg(-1), indicating a threshold for maximum root inherent potential. Therefore, to maintain efficient inherent potential of roots for P acquisition, we suggest that the target upper level of soil P in intensive agriculture should be reduced from the environmental risk threshold to the point maximizing the inherent potential of roots.

  2. Memory accessibility shapes explanation: Testing key claims of the inherence heuristic account.

    Science.gov (United States)

    Hussak, Larisa J; Cimpian, Andrei

    2018-01-01

    People understand the world by constructing explanations for what they observe. It is thus important to identify the cognitive processes underlying these judgments. According to a recent proposal, everyday explanations are often constructed heuristically: Because people need to generate explanations on a moment-by-moment basis, they cannot perform an exhaustive search through the space of possible reasons, but may instead use the information that is most easily accessible in memory (Cimpian & Salomon 2014a, b). In the present research, we tested two key claims of this proposal that have so far not been investigated. First, we tested whether-as previously hypothesized-the information about an entity that is most accessible in memory tends to consist of inherent or intrinsic facts about that entity, rather than extrinsic (contextual, historical, etc.) facts about it (Studies 1 and 2). Second, we tested the implications of this difference in the memory accessibility of inherent versus extrinsic facts for the process of generating explanations: Does the fact that inherent facts are more accessible than relevant extrinsic facts give rise to an inherence bias in the content of the explanations generated (Studies 3 and 4)? The findings supported the proposal that everyday explanations are generated in part via a heuristic process that relies on easily accessible-and often inherent-information from memory.

  3. Is the inherent potential of maize roots efficient for soil phosphorus acquisition?

    Directory of Open Access Journals (Sweden)

    Yan Deng

    Full Text Available Sustainable agriculture requires improved phosphorus (P management to reduce the overreliance on P fertilization. Despite intensive research of root adaptive mechanisms for improving P acquisition, the inherent potential of roots for efficient P acquisition remains unfulfilled, especially in intensive agriculture, while current P management generally focuses on agronomic and environmental concerns. Here, we investigated how levels of soil P affect the inherent potential of maize (Zea mays L. roots to obtain P from soil. Responses of root morphology, arbuscular mycorrhizal colonization, and phosphate transporters were characterized and related to agronomic traits in pot and field experiments with soil P supply from deficiency to excess. Critical soil Olsen-P level for maize growth approximated 3.2 mg kg(-1, and the threshold indicating a significant environmental risk was about 15 mg kg(-1, which represented the lower and upper levels of soil P recommended in current P management. However, most root adaptations involved with P acquisition were triggered when soil Olsen-P was below 10 mg kg(-1, indicating a threshold for maximum root inherent potential. Therefore, to maintain efficient inherent potential of roots for P acquisition, we suggest that the target upper level of soil P in intensive agriculture should be reduced from the environmental risk threshold to the point maximizing the inherent potential of roots.

  4. Results and implications of the EBR-II inherent safety demonstration tests

    International Nuclear Information System (INIS)

    Planchon, H.P.; Golden, G.H.; Sackett, J.I.; Mohr, D.; Chang, L.K.; Feldman, E.E.; Betten, P.R.

    1987-01-01

    On April 3, 1986 two milestone tests were conducted in Experimental Breeder Reactor-2 (EBR-II). The first test was a loss of flow without scram and the second was a loss of heat sink without scram. Both tests were initiated from 100% power and in both tests the reactor was shut down by natural processes, principally thermal expansion, without automatic scram, operator intervention or the help of special in-core devices. The temperature transients during the tests were mild, as predicted, and there was no damage to the core or reactor plant structures. In a general sense, therefore, the tests plus supporting analysis demonstrated the feasibility of inherent passive shutdown for undercooling accidents in metal-fueled LMRs. The results provide a technical basis for future experiments in EBR-II to demonstrate inherent safety for overpower accidents and provide data for validation of computer codes used for design and safety analysis of inherently safe reactor plants

  5. Deliberate practice theory: perceived relevance, effort, and inherent enjoyment of music practice: study II.

    Science.gov (United States)

    Hyllegard, Randy; Bories, Tamara L

    2009-10-01

    This study, based on the theory of deliberate practice, examined the practice relevance, effort, and inherent enjoyment aspects of the theory. 25 college undergraduates practiced playing a melody on an electronic keyboard for three 20-min. practice sessions. Following each session, the perceived relevance of the practice for improving performance of the melody, the effort needed to learn the melody, and the inherent enjoyment of the practice were each rated on 10-point scales. Findings were consistent with theory and similar to previous studies also involving music practice and other tasks.

  6. Impacts of reactivity feedback uncertainties on inherent shutdown in innovative designs

    International Nuclear Information System (INIS)

    Mueller, C.J.

    1986-01-01

    The concept of inherent shutdown is emphasized in the approach to the design of innovative, small pool-type liquid-metal reactors (LMRs). This paper reports an evaluation of reactivity feedback uncertainties used in the analyses of anticipated transients without scram for innovative LMRs, and the associated impacts on safety margins and inherent shutdown success probabilities on unprotected loss-of-flow (LOF) events. It then assesses the ultimate importance of these uncertainties on LOF and transient overpower events in evolving metal and oxide innovative designs

  7. Chimera Type Behavior in Nonlocal Coupling System with Two Different Inherent Frequencies

    Science.gov (United States)

    Lin, Larry; Li, Ping-Cheng; Tseng, Hseng-Che

    2014-03-01

    From the research of Kuramoto and Strogatz, arrays of identical oscillators can display a remarkable pattern, named chimera state, in which phase-locked oscillators coexist with drifting ones in nonlocal coupling oscillator system. We consider further in this study, two groups of oscillators with different inherent frequencies and arrange them in a ring. When the difference of the inherent frequencies is within some specific parameter range, oscillators of nonlocal coupling system show two distinct chimera states. When the parameter value exceeds some threshold value, two chimera states disappear. They show different features. The statistical dynamic behavior of the system can be described by Kuramoto theory.

  8. Inherent safe design of advanced high temperature reactors - concepts for future nuclear power plants

    International Nuclear Information System (INIS)

    Hodzic, A.; Kugeler, K.

    1997-01-01

    This paper discusses the applicable solutions for a commercial size High Temperature Reactor (HTR) with inherent safety features. It describes the possible realization using an advanced concept which combines newly proposed design characteristics with some well known and proven HTR inherent safety features. The use of the HTR technology offers the conceivably best solution to meet the legal criteria, recently stated in Germany, for the future reactor generation. Both systems, block and pebble bed ,reactor, could be under certain design conditions self regulating in terms of core nuclear heat, mechanical stability and the environmental transfer. 23 refs., 7 figs

  9. Probabilities of inherent shutdown of unprotected events in innovative liquid metal reactors

    International Nuclear Information System (INIS)

    Mueller, C.J.

    1987-01-01

    The uncertainty in predicting the effectiveness of inherent shutdown (ISD) in innovative designs results from three broad contributing areas of uncertainty: (1) the inability to exactly predict the frequency of ATWS events with potential to challenge the safety systems and require ISD; (2) the approximation of representing all such ATWS events by a selected set of ''generic scenarios''; and (3) the inability to exactly calculate the core response to the selected generic scenarios. In this summary, the methodology and associated results of work used to establish probabilities of failure of inherent shutdown of innovative LMRs to the unprotected loss-of-flow (LOF) accident are discussed

  10. Government can regulate food advertising to children because cognitive research shows that it is inherently misleading.

    Science.gov (United States)

    Graff, Samantha; Kunkel, Dale; Mermin, Seth E

    2012-02-01

    The childhood obesity crisis has prompted repeated calls for government action to curb the marketing of unhealthy food to children. Food and entertainment industry groups have asserted that the First Amendment prohibits such regulation. However, case law establishes that the First Amendment does not protect "inherently misleading" commercial speech. Cognitive research indicates that young children cannot effectively recognize the persuasive intent of advertising or apply the critical evaluation required to comprehend commercial messages. Given this combination--that government can prohibit "inherently misleading" advertising and that children cannot adequately understand commercial messages--advertising to children younger than age twelve should be considered beyond the scope of constitutional protection.

  11. Inherent Limitations in Mid-Wave and Long-Wave-IR Upconversion Detector

    DEFF Research Database (Denmark)

    Barh, Ajanta; Tseng, Yu-Pei; Pedersen, Christian

    2017-01-01

    Inherent limitations in terms of optical losses, selection of nonlinear crystal(s), detection efficiency and pumping conditions in mid-wave (3-5 µm) and long-wave (8-12 µm) infrared frequency upconversion modules are investigated in this paper.......Inherent limitations in terms of optical losses, selection of nonlinear crystal(s), detection efficiency and pumping conditions in mid-wave (3-5 µm) and long-wave (8-12 µm) infrared frequency upconversion modules are investigated in this paper....

  12. Impacts of reactivity feedback uncertainties on inherent shutdown in innovative designs

    International Nuclear Information System (INIS)

    Mueller, C.J.

    1986-01-01

    The concept of ''inherent shutdown'' is emphasized in the approach to the design of innovative, small pool-type liquid metal reactors (LMRs). This paper reports an evaluation of reactivity feedback uncertainties used in the analyses of anticipated transients without scram (ATWS) for innovative LMRs, and the associated impacts on safety margins and inherent shutdown success probabilities on unprotected loss-of-flow (LOF) events. It then assesses the ultimate importance of these uncertainties on LOF and transient overpower (TOP) events in evolving metal and oxide innovative designs

  13. Controversial socio-scientific issues / Controvérsias sociocientíficas: aspectos metodológicos para a aproximação...

    OpenAIRE

    Ralph Levinson; Danilo Seithi Kato

    2016-01-01

    Entrevista com Ralph Levinson coordenada pelo Prof. Dr. Danilo Seithi Kato (UFTM). Ralph Levinson é professor do Instituto de Educação da Universidade de Londres. Ele dirige o mestrado em Educação para Ciências e orienta trabalhos de doutorado. Seus interesses de pesquisa são questões sociocientíficas controversas, ciência e justiça social, educação para ciências e criatividade e pedagogia em ciência. Ele é o autor de “Towards a theoretical framework for teaching controversial socio‐scientifi...

  14. A Perspective on Knowing about Global Warming and a Critical Comment about Schools and Curriculum in Relation to Socio-Scientific Issues

    Science.gov (United States)

    Levinson, Ralph

    2012-01-01

    The focus of this response to Virginie Albe and Marie-Jose Gombert's (2011) article on a research study of students' school science conference on global warming is to develop some thoughts on covert assumptions which underpin any such conference. My comments refer to the politics behind the production of scientific knowledge of climate change and…

  15. Using Social Network Graphs as Visualization Tools to Influence Peer Selection Decision-Making Strategies to Access Information about Complex Socioscientific Issues

    Science.gov (United States)

    Yoon, Susan A.

    2011-01-01

    This study extends previous research that explores how visualization affordances that computational tools provide and social network analyses that account for individual- and group-level dynamic processes can work in conjunction to improve learning outcomes. The study's main hypothesis is that when social network graphs are used in instruction,…

  16. The Market for Academic Knowledge: Its Historical Emergence and Inherent Tensions

    Science.gov (United States)

    Weik, Elke

    2014-01-01

    This paper contributes to the discussion about the marketisation of universities by providing a historical perspective. Going back to the time when the market for academic knowledge emerged, I argue that it was created through incorporating a number of inherent tensions that have been, and still are, shaping its development. I show how these…

  17. Generalizing a model beyond the inherence heuristic and applying it to beliefs about objective value.

    Science.gov (United States)

    Wood, Graham

    2014-10-01

    The inherence heuristic is characterized as part of an instantiation of a more general model that describes the interaction between undeveloped intuitions, produced by System 1 heuristics, and developed beliefs, constructed by System 2 reasoning. The general model is described and illustrated by examining another instantiation of the process that constructs belief in objective moral value.

  18. Remote sensing reflectance and inherent optical properties of oceanic waters derived from above-water measurements

    Science.gov (United States)

    Lee, Zhongping; Carder, Kendall L.; Steward, Robert G.; Peacock, Thomas G.; Davis, Curtiss O.; Mueller, James L.

    1997-02-01

    Remote-sensing reflectance and inherent optical properties of oceanic properties of oceanic waters are important parameters for ocean optics. Due to surface reflectance, Rrs or water-leaving radiance is difficult to measure from above the surface. It usually is derived by correcting for the reflected skylight in the measured above-water upwelling radiance using a theoretical Fresnel reflectance value. As it is difficult to determine the reflected skylight, there are errors in the Q and E derived Rrs, and the errors may get bigger for high chl_a coastal waters. For better correction of the reflected skylight,w e propose the following derivation procedure: partition the skylight into Rayleigh and aerosol contributions, remove the Rayleigh contribution using the Fresnel reflectance, and correct the aerosol contribution using an optimization algorithm. During the process, Rrs and in-water inherent optical properties are derived at the same time. For measurements of 45 sites made in the Gulf of Mexico and Arabian Sea with chl_a concentrations ranging from 0.07 to 49 mg/m3, the derived Rrs and inherent optical property values were compared with those from in-water measurements. These results indicate that for the waters studied, the proposed algorithm performs quite well in deriving Rrs and in- water inherent optical properties from above-surface measurements for clear and turbid waters.

  19. Thermosetting resins with high fractions of free volume and inherently low dielectric constants.

    Science.gov (United States)

    Lin, Liang-Kai; Hu, Chien-Chieh; Su, Wen-Chiung; Liu, Ying-Ling

    2015-08-18

    This work demonstrates a new class of thermosetting resins, based on Meldrum's acid (MA) derivatives, which have high fractions of free volume and inherently low k values of about 2.0 at 1 MHz. Thermal decomposition of the MA groups evolves CO2 and acetone to create air-trapped cavities so as to reduce the dielectric constants.

  20. An corrective method to correct of the inherent flaw of the asynchronization direct counting circuit

    International Nuclear Information System (INIS)

    Wang Renfei; Liu Congzhan; Jin Yongjie; Zhang Zhi; Li Yanguo

    2003-01-01

    As a inherent flaw of the Asynchronization Direct Counting Circuit, the crosstalk, which is resulted from the randomicity of the time-signal always exists between two adjacent channels. In order to reduce the counting error derived from the crosstalk, the author propose an effective method to correct the flaw after analysing the mechanism of the crosstalk

  1. Location estimation of approaching objects is modulated by the observer's inherent and momentary action capabilities

    NARCIS (Netherlands)

    Kandula, Manasa; Hofman, Dennis; Dijkerman, H Chris

    2016-01-01

    Action capability may be one of the factors that can influence our percept of the world. A distinction can be made between momentary action capability (action capability at that particular moment) and inherent action capability (representing a stable action capability). In the current study, we

  2. 16 CFR 1211.13 - Inherent force activated secondary door sensors.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Inherent force activated secondary door sensors. 1211.13 Section 1211.13 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT... across the door so that the axis is perpendicular to the plane of the door. See Figure 6 of this part...

  3. 40 CFR 88.312-93 - Inherently Low-Emission Vehicle labeling.

    Science.gov (United States)

    2010-07-01

    ... stroke width not less than 0.5 inches (1.3 centimeters). In addition, the words “INHERENTLY LOW-EMISSION..., the words “CLEAN AIR VEHICLE” must be present in lettering no smaller than 0.8 inches (2.0 centimeters... loan to someone who has not demonstrated eligibility for expanded TCMs available to ILEVs according to...

  4. [The concentration of growth factors in patients with inherent and acquired shortenings of limbs bones].

    Science.gov (United States)

    Strogov, M V; Luneva, S N; Novikov, K I

    2013-04-01

    The article deals with the results of study of level of growth factors in blood serum of patients with inherent and post-traumatic shortenings of limbs' bones. The detection in blood serum the level of epidermal growth factor insulin-like growth factor I and angiopoetins is proposed to monitor in given patients the reparative bone formation.

  5. Toxic release consequence analysis tool (TORCAT) for inherently safer design plant

    International Nuclear Information System (INIS)

    Shariff, Azmi Mohd; Zaini, Dzulkarnain

    2010-01-01

    Many major accidents due to toxic release in the past have caused many fatalities such as the tragedy of MIC release in Bhopal, India (1984). One of the approaches is to use inherently safer design technique that utilizes inherent safety principle to eliminate or minimize accidents rather than to control the hazard. This technique is best implemented in preliminary design stage where the consequence of toxic release can be evaluated and necessary design improvements can be implemented to eliminate or minimize the accidents to as low as reasonably practicable (ALARP) without resorting to costly protective system. However, currently there is no commercial tool available that has such capability. This paper reports on the preliminary findings on the development of a prototype tool for consequence analysis and design improvement via inherent safety principle by utilizing an integrated process design simulator with toxic release consequence analysis model. The consequence analysis based on the worst-case scenarios during process flowsheeting stage were conducted as case studies. The preliminary finding shows that toxic release consequences analysis tool (TORCAT) has capability to eliminate or minimize the potential toxic release accidents by adopting the inherent safety principle early in preliminary design stage.

  6. The Inherent Politics of Managing the Quality of Urban Green Spaces

    DEFF Research Database (Denmark)

    Lindholst, Christian; Sullivan, Sidney George; Konijnendijk van den Bosch, Cecil C.

    2015-01-01

    of such ‘inherent politics’ through a case study of a widespread approach to operationalizing quality in urban green space management. We conclude that adoption of any quality model has both limiting and enabling implications for public participation and decision-making and that a critical stance is needed within...

  7. Manson Chicks and Microskirted Cuties : Pornification in Thomas Pynchon's Inherent Vice

    NARCIS (Netherlands)

    Cook, S.J.|info:eu-repo/dai/nl/411939432

    2015-01-01

    Many sexual encounters in Thomas Pynchon’s fiction have occurred beyond the mainstream, generating theatres of perversity which dramatise the death wish and enact power relations from wider arenas. However, in Inherent Vice they change in nature. With the exception of scenes which use Charles Manson

  8. Development status of PIUS/ISER - a inherently safe reactor for the international use

    International Nuclear Information System (INIS)

    Wakabayashi, Hiroaki

    1987-01-01

    It is just in early 1980s that LWR-based nuclear power has become a substantial power source. Though the safety level of nuclear power is always claimed to be sufficiently high by the industry, it rests on the idea of defense in depth, the calculation by probabilistic risk assessment (PRA) or probabilistic safety assessment (PSA). The TMI-2 and Chernobyl-4 accidents occurred in the industrially most advanced countries. In this paper, an alternative way to safe nuclear power is sought in so-called inherently safe reactors (ISR) including the LWR type PIUS/ISER. With proper consideration into the design of nuclear reactor plants, those can be made basically safe through the use of passive safe mechanism for their design. In short, an ISR is a nuclear power reactor which has passive and intrinsic core cooling capability and automatic shutdown capability. As the nuclear power reactors which are currently claimed to be inherently safe, there are the process inherent and ultimately safe reactor (PIUS) of ASEA-ATOM Sweden and the inherently safe and economical reactor (ISER) of the University of Tokyo, Japan, of LWR type. The current status of the development, the reliability, and some technical problems of ISER/PIUS and the attitude of various countries toward ISER/PIUS are described. (Kako, I.)

  9. Food plant toxicants and safety: risk assessment and regulation of inherent toxicants in plant foods.

    NARCIS (Netherlands)

    Essers, A.J.; Alink, G.M.; Speijers, G.J.A.; Alexander, J.; Bouwmeister, P.J.; Brandt, van den P.A.; Ciere, S.; Gry, J.; Herrman, J.; Kuiper, H.A.; Mortby, E.; Renwickn, A.G.

    1998-01-01

    The ADI as a tool for risk management and regulation of food additives and pesticide residues is not readily applicable to inherent food plant toxicants: The margin between actual intake and potentially toxic levels is often small; application of the default uncertainty factors used to derive ADI

  10. Unlocking variability: inherent variation and developmental traits of garlic plants originated from sexual reproduction

    NARCIS (Netherlands)

    Shemesh, E.; Scholten, O.E.; Rabinowitch, H.D.; Kamenetsky, R.

    2008-01-01

    Recent collections of fertile garlic (Allium sativum) accessions from Central Asia allow a detailed study of seedling developments and the evaluation of inherent variations. We hereby provide a comprehensive account of the ontogenesis of a population of garlic seedlings and their vegetative and

  11. The attractive Achilles heel of germ cell tumours : an inherent sensitivity to apoptosis-inducing stimuli

    NARCIS (Netherlands)

    Spierings, DCJ; de Vries, EGE; Vellenga, E; de Jong, S

    Testicular germ cell tumours (TGCTs) are extremely sensitive to cisplatin-containing chemotherapy. The rapid time course of apoptosis induction after exposure to cisplatin suggests that TGCT cells are primed to undergo programmed cell death as an inherent property of the cell of origin. In fact,

  12. Efficiency of inherent protection mechanisms for an improved HTR safety concept

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, K.; Buescher, R.; Gerwin, H.; Schenk, W. [Kernforschungsanlage Juelich G.m.b.H. (Germany, F.R.). Inst. fuer Reaktorentwicklung

    1981-01-15

    For a preliminary design of a 350 MWsub(th) annular core derived from AVR-reactor the efficiency of inherent protection mechanisms is discussed. After-heat removal and auto-shut down potential are demonstrated for intact and complete failure of core heat sinks.

  13. Making the Grade: Describing Inherent Requirements for the Initial Teacher Education Practicum

    Science.gov (United States)

    Sharplin, Elaine; Peden, Sanna; Marais, Ida

    2016-01-01

    This study explores the development, description, and illustration of inherent requirement (IR) statements to make explicit the requirements for performance on an initial teacher education (ITE) practicum. Through consultative group processes with stakeholders involved in ITE, seven IR domains were identified. From interviews with academics,…

  14. Inherent Safety Feature of Hybrid Low Power Research Reactor during Reactivity Induced Accident

    Energy Technology Data Exchange (ETDEWEB)

    Kim, DongHyun; Yum, Soo Been; Hong, Sung Teak; Lim, In-Cheol [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    Hybrid low power research reactor(H-LPRR) is the new design concept of low power research reactor for critical facility as well as education and training. In the case of typical low power research reactor, the purposes of utilization are the experiments for education of nuclear engineering students, Neutron Activation Analysis(NAA) and radio-isotope production for research purpose. H-LPRR is a light-water cooled and moderated research reactor that uses rod-type LEU UO{sub 2} fuels same as those for commercial power plants. The maximum core thermal power is 70kW and, the core is placed in the bottom of open pool. There are 1 control rod and 2 shutdown rods in the core. It is designed to cool the core by natural convection, retain negative feedback coefficient for entire fuel periods and operate for 20 years without refueling. Inherent safety in H-LPRR is achieved by passive design features such as negative temperature feedback coefficient and core cooling by natural convection during normal and emergency conditions. The purpose of this study is to find out that the inherent safety characteristics of H-LPRR is able to control the power and protect the reactor from the RIA(Reactivity induced accident). RIA analysis was performed to investigate the inherent safety feature of H-LPRR. As a result, it was found that the reactor controls its power without fuel damage in the event and that the reactor remains safe states inherently. Therefore, it is believed that high degree of safety inheres in H-LPRR.

  15. Family Issues

    Science.gov (United States)

    ... es Autismo? Family Issues Home / Living with Autism / Family Issues Stress Siblings A child’s autism diagnosis affects every member of the family in different ways. Parents/caregivers must now place their ... may put stress on their marriage, other children, work, finances, and ...

  16. Multi-objective optimization of a cascade refrigeration system: Exergetic, economic, environmental, and inherent safety analysis

    International Nuclear Information System (INIS)

    Eini, Saeed; Shahhosseini, Hamidreza; Delgarm, Navid; Lee, Moonyong; Bahadori, Alireza

    2016-01-01

    Highlights: • A multi-objective optimization is performed for a cascade refrigeration cycle. • The optimization problem considers inherently safe design as well as 3E analysis. • As a measure of inherent safety level a quantitative risk analysis is utilized. • A CO 2 /NH 3 cascade refrigeration system is compared with a CO 2 /C 3 H 8 system. - Abstract: Inherently safer design is the new approach to maximize the overall safety of a process plant. This approach suggests some risk reduction strategies to be implemented in the early stages of design. In this paper a multi-objective optimization was performed considering economic, exergetic, and environmental aspects besides evaluation of the inherent safety level of a cascade refrigeration system. The capital costs, the processing costs, and the social cost due to CO 2 emission were considered to be included in the economic objective function. Exergetic efficiency of the plant was considered as the second objective function. As a measure of inherent safety level, Quantitative Risk Assessment (QRA) was performed to calculate total risk level of the cascade as the third objective function. Two cases (ammonia and propane) were considered to be compared as the refrigerant of the high temperature circuit. The achieved optimum solutions from the multi–objective optimization process were given as Pareto frontier. The ultimate optimal solution from available solutions on the Pareto optimal curve was selected using Decision-Makings approaches. NSGA-II algorithm was used to obtain Pareto optimal frontiers. Also, three decision-making approaches (TOPSIS, LINMAP, and Shannon’s entropy methods) were utilized to select the final optimum point. Considering continuous material release from the major equipment in the plant, flash and jet fire scenarios were considered for the CO 2 /C 3 H 8 cycle and toxic hazards were considered for the CO 2 /NH 3 cycle. The results showed no significant differences between CO 2 /NH 3 and

  17. Global Issues

    Energy Technology Data Exchange (ETDEWEB)

    Seitz, J.L.

    2001-10-15

    Global Issues is an introduction to the nature and background of some of the central issues - economic, social, political, environmental - of modern times. This new edition of this text has been fully updated throughout and features expanded sections on issues such as global warming, biotechnology, and energy. Fully updated throughout and features expanded sections on issues such as global warming, biotechnology, and energy. An introduction to the nature and background of some of the central issues - economic, social, political, environmental - of modern times. Covers a range of perspectives on a variety of societies, developed and developing. Extensively illustrated with diagrams and photographs, contains guides to further reading, media, and internet resources, and includes suggestions for discussion and studying the material. (author)

  18. Inherent optical properties of pollen particles: a case study for the morning glory pollen.

    Science.gov (United States)

    Liu, Chao; Yin, Yan

    2016-01-25

    Biological aerosols, such as bacteria, fungal spores, and pollens, play an important role on various atmospheric processes, whereas their inherent optical property is one of the most uncertainties that limit our ability to assess their effects on weather and climate. A numerical model with core-shell structure, hexagonal grids and barbs is developed to represent one kind of realistic pollen particles, and their inherent optical properties are simulated using a pseudo-spectral time domain method. Both the hexagonal grids and barbs substantially affect the modeled pollen optical properties. Results based on the realistic particle model are compared with two equivalent spherical approximations, and the significant differences indicate the importance of considering pollen geometries for their optical properties.

  19. Searching for Models Exhibiting High Circularly Polarized Luminescence: the Electroactive Inherently Chiral Oligothiophenes.

    Science.gov (United States)

    Benincori, Tiziana; Appoloni, Giulio; Mussini, Patrizia Romana; Arnaboldi, Serena; Cirilli, Roberto; Quartapelle Procopio, Elsa; Panigati, Monica; Abbate, Sergio; Mazzeo, Giuseppe; Longhi, Giovanna

    2018-05-02

    Two new inherently chiral oligothiophenes characterized by the atropisomeric 3,3'-bithianaphtene scaffold functionalized with fused ring bithiophene derivatives, namely 4H-cyclopenta [2,1-b3:4b']dithiophene (CPDT) and dithieno[3,3-b:2',3'-d]pyrrole (DTP), were synthesized. The racemates were fully characterized and resolved into antipodes by enantioselective HPLC. The enantiomers were analyzed through different chiroptical techniques: electronic circular dichroism (ECD) and vibrational circular dichroism (VCD) were employed to attribute the absolute configuration (AC). Comparison of experimental and calculated VCD spectra confirmed the DFT calculated conformational characteristics. The compound functionalized with two CPDT units was oxidized with FeCl3 and ECD and CPL of the resulting material were measured. Circularly Polarized Luminescence (CPL) was measured in order to verify if inherently chiral oligothiophenes could be promising systems for chiral photonics applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Integral Inherently Safe Light Water Reactor (I2S-LWR)

    International Nuclear Information System (INIS)

    Petrovic, Bojan; Memmott, Matthew; Boy, Guy; Charit, Indrajit; Manera, Annalisa; Downar, Thomas; Lee, John; Muldrow, Lycurgus; Upadhyaya, Belle; Hines, Wesley; Haghighat, Alierza

    2017-01-01

    This final report summarizes results of the multi-year effort performed during the period 2/2013- 12/2016 under the DOE NEUP IRP Project ''Integral Inherently Safe Light Water Reactors (I 2 S-LWR)''. The goal of the project was to develop a concept of a 1 GWe PWR with integral configuration and inherent safety features, at the same time accounting for lessons learned from the Fukushima accident, and keeping in mind the economic viability of the new concept. Essentially (see Figure 1-1) the project aimed to implement attractive safety features, typically found only in SMRs, to a larger power (1 GWe) reactor, to address the preference of some utilities in the US power market for unit power level on the order of 1 GWe.

  1. Inherent wettability of different rock surfaces at nanoscale: a theoretical study

    Science.gov (United States)

    Chang, Xiao; Xue, Qingzhong; Li, Xiaofang; Zhang, Jianqiang; Zhu, Lei; He, Daliang; Zheng, Haixia; Lu, Shuangfang; Liu, Zilong

    2018-03-01

    Investigating the inherent wettability of rock surfaces at nanoscale is of great importance in ore floatation and oil recovery field. Using molecular dynamics simulations, we systematically study the wetting behavior of water on different rock surfaces (silica, calcite, gypsum, halite and graphite) at nanoscale. It is demonstrated that the inherent rock wettability follows the order of gypsum > calcite > halite > silica > graphite. Remarkably, we also manifest that the polarity of oil molecules can affect the water contact angles on silica surface. For example, the water contact angles on silica surface in hexane, dodecane, thiophene and toluene are 58 ± 2°, 63 ± 3°, 90 ± 1°, 118 ± 1°, respectively. Furthermore, we investigate the wetting behavior of water on heterogeneous rock surfaces and find that water molecules can move from hydrophobic surface to hydrophilic surface.

  2. Passive and inherent safety technologies for light-water nuclear reactors

    International Nuclear Information System (INIS)

    Forsberg, C.W.

    1990-07-01

    Passive/inherent safety implies a technical revolution in our approach to nuclear power safety. This direction is discussed herein for light-water reactors (LWRs) -- the predominant type of power reactor used in the world today. At Oak Ridge National Laboratory (ORNL) the approach to the development of passive/inherent safety for LWRs consists of four steps: identify and quantify safety requirements and goals; identify and quantify the technical functional requirements needed for safety; identify, invent, develop, and quantify technical options that meet both of the above requirements; and integrate safety systems into designs of economic and reliable nuclear power plants. Significant progress has been achieved in the first three steps of this program. The last step involves primarily the reactor vendors. These activities, as well as related activities worldwide, are described here. 27 refs., 7 tabs

  3. Integral Inherently Safe Light Water Reactor (I2S-LWR)

    Energy Technology Data Exchange (ETDEWEB)

    Petrovic, Bojan [Georgia Inst. of Technology, Atlanta, GA (United States); Memmott, Matthew [Brigham Young Univ., Provo, UT (United States); Boy, Guy [Florida Inst. of Technology, Melbourne, FL (United States); Charit, Indrajit [Univ. of Idaho, Moscow, ID (United States); Manera, Annalisa [Univ. of Michigan, Ann Arbor, MI (United States); Downar, Thomas [Univ. of Michigan, Ann Arbor, MI (United States); Lee, John [Univ. of Michigan, Ann Arbor, MI (United States); Muldrow, Lycurgus [Morehouse College, Atlanta, GA (United States); Upadhyaya, Belle [Univ. of Tennessee, Knoxville, TN (United States); Hines, Wesley [Univ. of Tennessee, Knoxville, TN (United States); Haghighat, Alierza [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

    2017-10-02

    This final report summarizes results of the multi-year effort performed during the period 2/2013- 12/2016 under the DOE NEUP IRP Project “Integral Inherently Safe Light Water Reactors (I2S-LWR)”. The goal of the project was to develop a concept of a 1 GWe PWR with integral configuration and inherent safety features, at the same time accounting for lessons learned from the Fukushima accident, and keeping in mind the economic viability of the new concept. Essentially (see Figure 1-1) the project aimed to implement attractive safety features, typically found only in SMRs, to a larger power (1 GWe) reactor, to address the preference of some utilities in the US power market for unit power level on the order of 1 GWe.

  4. Is damage to the common bile duct during laparoscopic cholecystectomy an inherent risk of the operation?

    Science.gov (United States)

    Fischer, Josef E

    2009-06-01

    Laparoscopic cholocystectomy has been practiced for close to 20 years. The rate of common duct injury remains somewhere between 0.4 to 0.7 percent and is approximately the same around the world. Recent papers have stressed ways in which laparoscopic common duct injury can be avoided, but none of the methods mentioned is foolproof. In addition, this complication can occur to even the most experienced laparoscopic surgeon. The author believes that injury to the common duct during laparoscopic cholocystectomy is not a result of the practice below the standard, but an inherent risk of the operation. This injury needs to be emphasized by the surgical community as an inherent risk of the operation, and patients should be fully informed of this potential complication.

  5. Role of FFTF in assessing structural feedbacks and inherent safety of LMR's

    International Nuclear Information System (INIS)

    Padilla, A.; Omberg, R.P.; O'Dell, L.D.; Harris, R.A.; Nguyen, D.H.; Waltar, A.E.

    1985-03-01

    The possibility of developing reactor designs with inherent safety characteristics sufficient to provide ''walk away'' safety is receiving additional emphasis in the LMR program. A key element in this effort is the recognition that LMR's possess safety characteristics above and beyond those employed in past safety review processes. Some of these additional safety characteristics are due to reactivity feedback effects caused by small structural movements during hypothetical severe design transients. The effect of these characteristics upon the behavior of the FFTF under such transients has been assessed and is discussed in this paper. The paper also presents a preliminary test matrix which might allow experimental verification of the structural reactivity feedback effects. Such experimental verification should be very useful to innovative designers seeking to optimize inherent safety. 8 refs., 1 fig., 2 tabs

  6. An assessment of the low seismic risk of the inherently safe sodium advanced fast reactor (SAFR)

    International Nuclear Information System (INIS)

    Rutherford, P.D.

    1988-01-01

    A recent probabilistic risk assessment (PRA) of the sodium advanced fast reactor (SAFR) demonstrated the inherently low risk of advanced liquid-metal, pool-type fast reactors with inherent safety systems. As a result, it was recognized that external events, especially seismic events, may not only be a major contributor to risk (as shown in several LWR PRAs) but also may completely dominate the risk. Accordingly, a seismic risk assessment has been completed for SAFR, which resulted in a core damage frequency of 2 x 10 -7 /year and a large release frequency of 4 x 10 -9 /year. This paper reports that public health risk in terms of early fatality risk and latent fatality risk were also several orders of magnitude below the NRC safety goals and below recent LWR risks reported in NUREB/CR1150

  7. [Differences of inherent optical properties of inland lake water body in typical seasons].

    Science.gov (United States)

    Sun, De-Yong; Li, Yun-Mei; Wang, Qiao; Le, Cheng-Fen; Huang, Chang-Chun; Wang, Li-Zhen

    2008-05-01

    Inherent optical property is one of the important properties of water body, which lays the foundation for the establishment of water color analytical models. By using quantity filter technology (QFT) and BB9 backscattering meter, the absorption coefficients of chromophoric dissolved organic matter (CDOM) and total suspended matters (TSM) and the backscattering coefficient of TSM in the water body at Meiliang Bay of Taihu Lake were measured in summer and winter. Based on the spectral comparison of the absorption and backscattering coefficients, their differences between the two seasons were demonstrated, and the reasons that caused these differences were also explored in the context of their relations to the changes in water quality. Consequently, water environment condition could be revealed by using the inherent optical property. The relationship between the backscattering coefficient and the TSM concentration was established, which could provide supporting coefficients to the analytical models to be developed.

  8. Acoustic resonance scattering by a system of concentrically multilayered shells: the inherent background and resonance coefficients

    CERN Document Server

    Choi, M S; Lee, S H

    1999-01-01

    The inherent background coefficients that exactly describe the background amplitudes in the scattered field have been presented for the scattering of plane acoustic waves by a system of concentrically multilayered solid and/or fluid shells submerged in a fluid. The coefficients have been obtained by replacing the mechanical surface admittance function with the zero-frequency limit of the admittance function for the analogous fluid system, where the shear wave speeds in the solid layers are set to zero. By taking advantage of the concept of incoming and outgoing waves, we find the surface admittance function for the fluid system in such a form that the analytical generalization for any number of layers and the physical interpretation are very easy. The background coefficients obtained are independent of the bulk wave speeds in the system: they depend on the mass densities and the thickness of the shells. With increasing frequency, the inherent background undergoes a transition from the soft to the rigid backgr...

  9. Disease resistance is related to inherent swimming performance in Atlantic salmon

    OpenAIRE

    Castro, Vicente; Grisdale-Helland, Barbara; Jørgensen, Sven Martin; Helgerud, Jan; Claireaux, Guy; Farrell, Anthony P.; Krasnov, Aleksei; Helland, Ståle; Takle, Harald Rune

    2013-01-01

    Background Like humans, fish can be classified according to their athletic performance. Sustained exercise training of fish can improve growth and physical capacity, and recent results have documented improved disease resistance in exercised Atlantic salmon. In this study we investigated the effects of inherent swimming performance and exercise training on disease resistance in Atlantic salmon. Atlantic salmon were first classified as either poor or good according to their swimming per...

  10. Ethical problems inherent in psychological research based on internet communication as stored information

    DEFF Research Database (Denmark)

    Øhrstrøm, Peter; Dyhrberg, Johan

    2007-01-01

    This paper deals with certain ethical problems inherent in psychological research based on internet communication as stored information. Section 1 contains an analysis of research on Internet debates. In particular, it takes into account a famous example of deception for psychology research...... purposes. In section 2, the focus is on research on personal data in texts published on the Internet. Section 3 includes an attempt to formulate some ethical principles and guidelines, which should be regarded as fundamental in research on stored information....

  11. Quantification of the inherent uncertainty in the relaxation modulus and creep compliance of asphalt mixes

    Science.gov (United States)

    Kassem, Hussein A.; Chehab, Ghassan R.; Najjar, Shadi S.

    2017-08-01

    Advanced material characterization of asphalt concrete is essential for realistic and accurate performance prediction of flexible pavements. However, such characterization requires rigorous testing regimes that involve mechanical testing of a large number of laboratory samples at various conditions and set-ups. Advanced measurement instrumentation in addition to meticulous and accurate data analysis and analytical representation are also of high importance. Such steps as well as the heterogeneous nature of asphalt concrete (AC) constitute major factors of inherent variability. Thus, it is imperative to model and quantify the variability of the needed asphalt material's properties, mainly the linear viscoelastic response functions such as: relaxation modulus, E(t), and creep compliance, D(t). The objective of this paper is to characterize the inherent uncertainty of both E(t) and D(t) over the time domain of their master curves. This is achieved through a probabilistic framework using Monte Carlo simulations and First Order approximations, utilizing E^{*} data for six AC mixes with at least eight replicates per mix. The study shows that the inherent variability, presented by the coefficient of variation (COV), in E(t) and D(t) is low at small reduced times, and increases with the increase in reduced time. At small reduced times, the COV in E(t) and D(t) are similar in magnitude; however, differences become significant at large reduced times. Additionally, the probability distributions and COVs of E(t) and D(t) are mix dependent. Finally, a case study is considered in which the inherent uncertainty in D(t) is forward propagated to assess the effect of variability on the predicted number of cycles to fatigue failure of an asphalt mix.

  12. Experimental evidence for inherent Lévy search behaviour in foraging animals.

    Science.gov (United States)

    Kölzsch, Andrea; Alzate, Adriana; Bartumeus, Frederic; de Jager, Monique; Weerman, Ellen J; Hengeveld, Geerten M; Naguib, Marc; Nolet, Bart A; van de Koppel, Johan

    2015-05-22

    Recently, Lévy walks have been put forward as a new paradigm for animal search and many cases have been made for its presence in nature. However, it remains debated whether Lévy walks are an inherent behavioural strategy or emerge from the animal reacting to its habitat. Here, we demonstrate signatures of Lévy behaviour in the search movement of mud snails (Hydrobia ulvae) based on a novel, direct assessment of movement properties in an experimental set-up using different food distributions. Our experimental data uncovered clusters of small movement steps alternating with long moves independent of food encounter and landscape complexity. Moreover, size distributions of these clusters followed truncated power laws. These two findings are characteristic signatures of mechanisms underlying inherent Lévy-like movement. Thus, our study provides clear experimental evidence that such multi-scale movement is an inherent behaviour rather than resulting from the animal interacting with its environment. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  13. Disease resistance is related to inherent swimming performance in Atlantic salmon.

    Science.gov (United States)

    Castro, Vicente; Grisdale-Helland, Barbara; Jørgensen, Sven M; Helgerud, Jan; Claireaux, Guy; Farrell, Anthony P; Krasnov, Aleksei; Helland, Ståle J; Takle, Harald

    2013-01-21

    Like humans, fish can be classified according to their athletic performance. Sustained exercise training of fish can improve growth and physical capacity, and recent results have documented improved disease resistance in exercised Atlantic salmon. In this study we investigated the effects of inherent swimming performance and exercise training on disease resistance in Atlantic salmon.Atlantic salmon were first classified as either poor or good according to their swimming performance in a screening test and then exercise trained for 10 weeks using one of two constant-velocity or two interval-velocity training regimes for comparison against control trained fish (low speed continuously). Disease resistance was assessed by a viral disease challenge test (infectious pancreatic necrosis) and gene expression analyses of the host response in selected organs. An inherently good swimming performance was associated with improved disease resistance, as good swimmers showed significantly better survival compared to poor swimmers in the viral challenge test. Differences in mortalities between poor and good swimmers were correlated with cardiac mRNA expression of virus responsive genes reflecting the infection status. Although not significant, fish trained at constant-velocity showed a trend towards higher survival than fish trained at either short or long intervals. Finally, only constant training at high intensity had a significant positive effect on fish growth compared to control trained fish. This is the first evidence suggesting that inherent swimming performance is associated with disease resistance in fish.

  14. Disease resistance is related to inherent swimming performance in Atlantic salmon

    Directory of Open Access Journals (Sweden)

    Castro Vicente

    2013-01-01

    Full Text Available Abstract Background Like humans, fish can be classified according to their athletic performance. Sustained exercise training of fish can improve growth and physical capacity, and recent results have documented improved disease resistance in exercised Atlantic salmon. In this study we investigated the effects of inherent swimming performance and exercise training on disease resistance in Atlantic salmon. Atlantic salmon were first classified as either poor or good according to their swimming performance in a screening test and then exercise trained for 10 weeks using one of two constant-velocity or two interval-velocity training regimes for comparison against control trained fish (low speed continuously. Disease resistance was assessed by a viral disease challenge test (infectious pancreatic necrosis and gene expression analyses of the host response in selected organs. Results An inherently good swimming performance was associated with improved disease resistance, as good swimmers showed significantly better survival compared to poor swimmers in the viral challenge test. Differences in mortalities between poor and good swimmers were correlated with cardiac mRNA expression of virus responsive genes reflecting the infection status. Although not significant, fish trained at constant-velocity showed a trend towards higher survival than fish trained at either short or long intervals. Finally, only constant training at high intensity had a significant positive effect on fish growth compared to control trained fish. Conclusions This is the first evidence suggesting that inherent swimming performance is associated with disease resistance in fish.

  15. Model development for the dynamic analysis of the OSU inherently safe reactor. Part 1

    International Nuclear Information System (INIS)

    Aybar, H.S.

    1992-01-01

    Faculty and students in the Nuclear Engineering Program at the Ohio State University (OSU) have proposed a conceptual design for an inherently safe 340 MWe power reactor. The design is based on the state-of-the-art technology of LWRs and the High Temperature Gas- cooled Reactors (HTGRs). The OSU Inherently Safe Reactor (OSU-ISR) concept uses shorter than standard BWR fuel elements in the reactor core. All the fluid on the primary side is contained within a Prestressed Concrete Reactor Vessel (PCRV). This important feature significantly reduces the probability of a LOCA. A new feature of the OSU-ISR is an operator independent steam driven Emergency Core Cooling System (ECCS) housed within the PCRV. In accident conditions where the steam generators are incapacitated, steam from the core drives a jet injector, which takes water from the suppression pool and pumps it into the core cavity to maintain core coverability. The preliminary analysis of the concept was performed as a design project in the Nuclear Engineering Program at the OSU during the Spring of 1985, and published in ''Nuclear Technology.'' The use of a PCRV for ducting and containment and the replacement of forced recirculation with natural circulation on the primary side significantly improve the inherent safety of the plant. Currently, work is in progress for the refinement of the OSU-ISR concept, partially supported by a grant from the U.S. Department of Energy

  16. Liver-inherent immune system: its role in blood-stage malaria.

    Science.gov (United States)

    Wunderlich, Frank; Al-Quraishy, Saleh; Dkhil, Mohamed A

    2014-01-01

    The liver is well known as that organ which is obligately required for the intrahepatocyte development of the pre-erythrocytic stages of the malaria-causative agent Plasmodium. However, largely neglected is the fact that the liver is also a central player of the host defense against the morbidity- and mortality-causing blood stages of the malaria parasites. Indeed, the liver is equipped with a unique immune system that acts locally, however, with systemic impact. Its main "antipodal" functions are to recognize and to generate effective immunoreactivity against pathogens on the one hand, and to generate tolerance to avoid immunoreactivity with "self" and harmless substances as dietary compounds on the other hand. This review provides an introductory survey of the liver-inherent immune system: its pathogen recognition receptors including Toll-like receptors (TLRs) and its major cell constituents with their different facilities to fight and eliminate pathogens. Then, evidence is presented that the liver is also an essential organ to overcome blood-stage malaria. Finally, we discuss effector responses of the liver-inherent immune system directed against blood-stage malaria: activation of TLRs, acute phase response, phagocytic activity, cytokine-mediated pro- and anti-inflammatory responses, generation of "protective" autoimmunity by extrathymic T cells and B-1 cells, and T cell-mediated repair of liver injuries mainly produced by malaria-induced overreactions of the liver-inherent immune system.

  17. Safety assessment in plant layout design using indexing approach: Implementing inherent safety perspective

    International Nuclear Information System (INIS)

    Tugnoli, Alessandro; Khan, Faisal; Amyotte, Paul; Cozzani, Valerio

    2008-01-01

    The design of layout plans requires adequate assessment tools for the quantification of safety performance. The general focus of the present work is to introduce an inherent safety perspective at different points of the layout design process. In particular, index approaches for safety assessment and decision-making in the early stages of layout design are developed and discussed in this two-part contribution. Part 1 (accompanying paper) of the current work presents an integrated index approach for safety assessment of early plant layout. In the present paper (Part 2), an index for evaluation of the hazard related to the potential of domino effects is developed. The index considers the actual consequences of possible escalation scenarios and scores or ranks the subsequent accident propagation potential. The effects of inherent and passive protection measures are also assessed. The result is a rapid quantification of domino hazard potential that can provide substantial support for choices in the early stages of layout design. Additionally, a case study concerning selection among various layout options is presented and analyzed. The case study demonstrates the use and applicability of the indices developed in both parts of the current work and highlights the value of introducing inherent safety features early in layout design

  18. Interdependency control : compensation strategies for the inherent vulnerability of critical infrastructure networks

    International Nuclear Information System (INIS)

    Mao, D.; Sotoodeh, M.; Monu, K.; Marti, J.R.; Srivastava, K.D.

    2009-01-01

    Today's increasingly interacting national critical infrastructures (NCIs) can tolerate most stochastic local disturbances. However, they are extremely fragile under global disturbances, as the latter may either push the whole system into a critical state or reveal many unexpected hidden interdependencies, inducing or triggering cascading failures among all possible layers. This robust yet fragile duality is an inherent vulnerability of modern infrastructures. It is therefore expected that weather-related disasters will be more frequent under a changing climate. This paper proposed an interdependency control strategy (ICS) that would maintain the survival of the most critical services, and compensate for this inherent vulnerability during emergency states. The paper also proposed a generalized adjacency matrix (GAM) to represent the physical interdependencies intra/inter of various infrastructure networks. The vulnerable section in the network can be identified, based on computed results of GAM, number of islands in the network, and influence domain(s) of each component. These features render ICS more effective and convincing. Last, the paper proposed a survivability index for isolated sub-networks and described relevant measures for improving this index during the four phases of emergency management. It was concluded that the proposed strategy is an effective means to reduce the inherent vulnerability and increase the resiliency of these critical infrastructures networks. 20 refs., 5 figs

  19. Possibility of a pressurized water reactor concept with highly inherent heat removal following capability

    International Nuclear Information System (INIS)

    Araya, Fumimasa; Murao, Yoshio

    1995-01-01

    If the core power inherently follows change in heat removal rate from the primary coolant system within small thermal expansion of the coolant which can be absorbed in a practical size of pressurizer, reactor systems may have more safety and load following capability. In order to know possibility and necessary conditions of a concept on reactor core and primary coolant system of a pressurized water reactor (PWR) with such 'highly inherent heat removal following capability', transient analyses on an ordinary two-loop PWR have been performed for a transient due to 50% change in heat removal with the RETRAN-02 code. The possibility of a PWR concept with the highly inherent heat removal following capability has been demonstrated under the conditions of the absolute value of ratio of the coolant density reactivity coefficient to the Doppler reactivity coefficient more than 10x10 3 kg·cm 3 which is two to three times larger than that at beginning of cycle (BOC) in an ordinary PWR and realized by elimination of the chemical shim, the 12% lower average linear heat generation rate of 17.9 kW/m, and the 1.5 times larger pressurizer volume than those of the ordinary PWR. (author)

  20. A compact, inherently safe liquid metal reactor plant concept for terrestrial defense power applications

    International Nuclear Information System (INIS)

    Magee, P.M.; Dubberley, A.E.; Lutz, D.E.; Palmer, R.S.

    1987-01-01

    A compact, inherently safe, liquid metal reactor concept based on the GE PRISM innovative LMR design has been developed for terrestrial defense power applications in the 2-50 MWe range. The concept uses a small, sodium-cooled, U-5%Zr metal fueled reactor contained within two redundant steel vessels. The core is designed to operate at a low power density and temperature (925 F) and can operate 30 years without refueling. One two primary coolant loops, depending upon the plant size, transport heat from the core to sodium-to-air, double-wall heat exchangers. Power is produced by a gas turbine operated in a closed ''bottoming'' cycle that employs intercoolers between the compressor stages and a recuperator. Inherent safety is provided by passive means only; operator action is not required to ensure plant safety even for events normally considered Beyond Design Basis Accidents. In addition to normal shutdown heat removal via the sodium-to-air heat exchangers, the design utilizes an inherently passive radiant vessel auxiliary cooling system similar to that designed for PRISM. The use of an air cycle gas turbine eliminates the cost and complexity of the sodium-water reactor pressure relief system required for a steam cycle sodium-cooled reactor

  1. Developing a model for hospital inherent safety assessment: Conceptualization and validation.

    Science.gov (United States)

    Yari, Saeed; Akbari, Hesam; Gholami Fesharaki, Mohammad; Khosravizadeh, Omid; Ghasemi, Mohammad; Barsam, Yalda; Akbari, Hamed

    2018-01-01

    Paying attention to the safety of hospitals, as the most crucial institute for providing medical and health services wherein a bundle of facilities, equipment, and human resource exist, is of significant importance. The present research aims at developing a model for assessing hospitals' safety based on principles of inherent safety design. Face validity (30 experts), content validity (20 experts), construct validity (268 examples), convergent validity, and divergent validity have been employed to validate the prepared questionnaire; and the items analysis, the Cronbach's alpha test, ICC test (to measure reliability of the test), composite reliability coefficient have been used to measure primary reliability. The relationship between variables and factors has been confirmed at 0.05 significance level by conducting confirmatory factor analysis (CFA) and structural equations modeling (SEM) technique with the use of Smart-PLS. R-square and load factors values, which were higher than 0.67 and 0.300 respectively, indicated the strong fit. Moderation (0.970), simplification (0.959), substitution (0.943), and minimization (0.5008) have had the most weights in determining the inherent safety of hospital respectively. Moderation, simplification, and substitution, among the other dimensions, have more weight on the inherent safety, while minimization has the less weight, which could be due do its definition as to minimize the risk.

  2. The impac t of a scientific issue aproac h on the scientific and technological literac y of youth and adults

    Directory of Open Access Journals (Sweden)

    Natalia Katherine García Ramírez

    2015-01-01

    Full Text Available The processes of the scientific and technological literacy (STL developed with communities of youth and adults do not usually emerge beyond the classroom, these are simply compulsory for obtaining a degree. In such a context, this paper presents the results of a research whose purpose was to analyze the impact of the discussion about controversial aspects of a socioscientific issue (SCI on the SLT process of a group of youth and adults who studied a secondary school program by cycles in the town of Chia, Cundinamarca (Colombia. Some SCI-based activities related to the pollution caused by the industrial action in the Rio Frio sub-basin river (Cundinamarca, Colombia were designed and implemented for the analysis. It was found that working with SCI in literacy processes allows the formation of a critical and participatory subject, thus encouraging the learning of science concepts and their relationship with social and technological implications.

  3. Mapping Satellite Inherent Optical Properties Index in Coastal Waters of the Yucatán Peninsula (Mexico

    Directory of Open Access Journals (Sweden)

    Jesús A. Aguilar-Maldonado

    2018-06-01

    Full Text Available The Yucatán Peninsula hosts worldwide-known tourism destinations that concentrate most of the Mexico tourism activity. In this region, tourism has exponentially increased over the last years, including wildlife oriented tourism. Rapid tourism development, involving the consequent construction of hotels and tourist commodities, is associated with domestic sewage discharges from septic tanks. In this karstic environment, submarine groundwater discharges are very important and highly vulnerable to anthropogenic pollution. Nutrient loadings are linked to harmful algal blooms, which are an issue of concern to local and federal authorities due to their recurrence and socioeconomic and human health costs. In this study, we used satellite products from MODIS (Moderate Resolution Imaging Spectroradiometer to calculate and map the satellite Inherent Optical Properties (IOP Index. We worked with different scenarios considering both holiday and hydrological seasons. Our results showed that the satellite IOP Index allows one to build baseline information in a sustainable mid-term or long-term basis which is key for ecosystem-based management.

  4. Deliberate practice theory: relevance, effort, and inherent enjoyment of music practice.

    Science.gov (United States)

    Hyllegard, Randy; Bories, Tamara L

    2008-10-01

    This study examined three assumptions of the theory of deliberate practice for practice playing music on an electronic keyboard. 40 undergraduate students, divided into two separate groups, practiced one of two music sequences and rated the relevance of practice for improving performance on the sequences, the amount of effort needed to learn the sequences, and the inherent enjoyment of practice sessions. Findings for each assumption were consistent with those suggested by theory but also showed that perceptions are affected by the amount of practice completed and performance of the skill.

  5. Inherently safe SNR shutdown system with Curie point controlled sensor/switch unit

    International Nuclear Information System (INIS)

    Mueller, K.; Norajitra, P.; Reiser, H.

    1987-02-01

    Inherent shutdown due to increase in the sodium temperature at the core outlet is triggered by interruption of the current supply to the electromagnet coupling of absorber elements via curie point controlled sensor/switch units. These switches are arranged above suitable fuel element positions and spatially independent of the shutdown elements. Compared with other similar systems very short response times are achieved. A prototype switch unit has already undergone extensive testing. These tests have confirmed that switching takes place in a very narrow temperature range. (orig./HP) [de

  6. The development of a small inherently safe homogeneous reactor for the production of medical isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Carlin, G.E.; Bonin, H.W., E-mail: george.carlin@rmc.ca [Royal Military College of Canada, Kingston, Ontario (Canada)

    2013-07-01

    The use of radioisotopes for various procedures in the health care industry has become one of the most important practices in medicine. New interest has been found in the use of liquid fueled nuclear reactors to produce these isotopes due to the ease of fuel processing and ability to efficiently use LEU as the fuel source. A version of this reactor is being developed at the Royal Military College of Canada to act as a successor to the SLOWPOKE-2 platform. The thermal hydraulic and transient characteristics of a 20 kWt version are being studied to verify inherent safety abilities. (author)

  7. On the inherent self-excited macroscopic randomness of chaotic three-body system

    OpenAIRE

    Liao, Shijun; Li, Xiaoming

    2014-01-01

    What is the origin of macroscopic randomness (uncertainty)? This is one of the most fundamental open questions for human being. In this paper, 10000 samples of reliable (convergent), multiple-scale (from 1.0E-60 to 100) numerical simulations of a chaotic three-body system indicate that, without any external disturbance, the microscopic inherent uncertainty (in the level of 1.0E-60) due to physical fluctuation of initial positions of the three-body system enlarges exponentially into macroscopi...

  8. Treatment of inherently unstable open or infected fractures by open wound management and external skeletal fixation.

    Science.gov (United States)

    Ness, M G

    2006-02-01

    To assess the use of external skeletal fixation with open wound management for the treatment of inherently unstable open or infected fractures in dogs. A retrospective review of 10 cases. Fracture stabilisation and wound management required only a single anaesthetic, and despite the challenging nature of these injuries, the final outcome was acceptable or good in every case. However, minor complications associated with the fixator pins were quite common, and two dogs developed complications which required additional surgery. Open management of wounds, even when bone was exposed, proved to be an effective technique, and external skeletal fixators were usually effective at maintaining stability throughout an inevitably extended fracture healing period.

  9. Multiformity of inherent randomicity and visitation density in n symbolic dynamics

    International Nuclear Information System (INIS)

    Zhang Yagang; Wang Changjiang

    2007-01-01

    The multiformity of inherent randomicity and visitation density in n symbolic dynamics will be clarified in this paper. These stochastic symbolic sequences bear three features. The distribution of frequency, inter-occurrence times and the alignment of two random sequences are amplified in detail. The features of visitation density in surjective maps presents catholicity and the catholicity in n letters randomicity has the same measure foundation. We hope to offer a symbolic platform that satisfies these stochastic properties and to attempt to study certain properties of DNA base sequences, 20 amino acids symbolic sequences of proteid structure, and the time series that can be symbolic in finance market et al

  10. Workforce Issues.

    Science.gov (United States)

    1996

    This document consists of four papers presented during a symposium on work force issues moderated by Jan DeJong at the 1996 conference of the Academy of Human Resource Development (AHRD). "Rethinking the Ties that Bind: An Exploratory Study of Employee Development in Utilities in Canada and the United States" (Michael Aherne, David…

  11. Sanskrit Issue.

    Science.gov (United States)

    Miller, Barbara Stoler, Ed.

    1971-01-01

    This issue of "Mahfil" is devoted to Sanskrit literature and contains a note on Sanskrit pronunciation and selections of Sanskrit literature. It also contains articles analyzing and discussing various aspects of the literature, including "Sanskrit Rhetoric and Poetic,""The Creative Role of the Goddess Vac in the…

  12. Bond Issues.

    Science.gov (United States)

    Pollack, Rachel H.

    2000-01-01

    Notes trends toward increased borrowing by colleges and universities and offers guidelines for institutions that are considering issuing bonds to raise money for capital projects. Discussion covers advantages of using bond financing, how use of bonds impacts on traditional fund raising, other cautions and concerns, and some troubling aspects of…

  13. Dynamics and inherent safety features of small modular high temperature gas-cooled reactors

    International Nuclear Information System (INIS)

    Harrington, R.M.; Ball, S.J.; Cleveland, J.C.

    1986-01-01

    Investigations were made at Oak Ridge National Laboratory to characterize the dynamics and inherent safety features of various modular high temperature gas-cooled reactor (HTGR) designs. This work was sponsored by the US Nuclear Regulatory Commission's HTGR Safety Research program. The US Department of Energy (DOE) and the Gas Cooled Reactor Associates (GCRA) have sponsored studies of several modular HTGR concepts, each having it own unique advantageous economic and inherent safety features. The DOE design team has recently choses a 350-MW(t) annular core with prismatic, graphite matrix fuel for its reference plant. The various safety features of this plant and of the pebble-bed core designs similar to those currently being developed and operated in the Federal Republic of Germany (FRG) are described. A varity of postulated accident sequences involving combinations of loss of forced circulation of the helium primary coolant, loss of primary coolant pressurization, and loss of normal and backup heat sinks were studied and are discussed. Results demonstrate that each concept can withstand an uncontrolled heatup accident without reaching excessive peak fuel temperatures. Comparisons of calculated and measured response for a loss of forced circulation test on the FRG reactor, AVR, are also presented. 10 refs

  14. DEM Simulation of Biaxial Compression Experiments of Inherently Anisotropic Granular Materials and the Boundary Effects

    Directory of Open Access Journals (Sweden)

    Zhao-Xia Tong

    2013-01-01

    Full Text Available The reliability of discrete element method (DEM numerical simulations is significantly dependent on the particle-scale parameters and boundary conditions. To verify the DEM models, two series of biaxial compression tests on ellipse-shaped steel rods are used. The comparisons on the stress-strain relationship, strength, and deformation pattern of experiments and simulations indicate that the DEM models are able to capture the key macro- and micromechanical behavior of inherently anisotropic granular materials with high fidelity. By using the validated DEM models, the boundary effects on the macrodeformation, strain localization, and nonuniformity of stress distribution inside the specimens are investigated using two rigid boundaries and one flexible boundary. The results demonstrate that the boundary condition plays a significant role on the stress-strain relationship and strength of granular materials with inherent fabric anisotropy if the stresses are calculated by the force applied on the wall. However, the responses of the particle assembly measured inside the specimens are almost the same with little influence from the boundary conditions. The peak friction angle obtained from the compression tests with flexible boundary represents the real friction angle of particle assembly. Due to the weak lateral constraints, the degree of stress nonuniformity under flexible boundary is higher than that under rigid boundary.

  15. A fit method for the determination of inherent filtration with diagnostic x-ray units

    International Nuclear Information System (INIS)

    Meghzifene, K; Nowotny, R; Aiginger, H

    2006-01-01

    A method for the determination of total inherent filtration for clinical x-ray units using attenuation curves was devised. A model for the calculation of x-ray spectra is used to calculate kerma values which are then adjusted to the experimental data in minimizing the sum of the squared relative differences in kerma using a modified simplex fit process. The model considers tube voltage, voltage ripple, anode angle and additional filters. Fit parameters are the thickness of an additional inherent Al filter and a general normalization factor. Nineteen sets of measurements including attenuation data for three tube voltages and five Al-filter settings each were obtained. Relative differences of experimental and calculated kerma using the data for the additional filter thickness are within a range of -7.6% to 6.4%. Quality curves, i.e. the relationship of additional filtration to HVL, are often used to determine filtration but the results show that standard quality curves do not reflect the variety of conditions encountered in practice. To relate the thickness of the additional filter to the condition of the anode surface, the data fits were also made using tungsten as the filter material. These fits gave an identical fit quality compared to aluminium with a tungsten filter thickness of 2.12-8.21 μm which is within the range of the additional absorbing layers determined for rough anodes

  16. Are autobiographical memories inherently social? Evidence from an fMRI study.

    Directory of Open Access Journals (Sweden)

    Linda Wilbers

    Full Text Available The story of our lifetime - our narrative self - is constructed from our autobiographical memories. A central claim of social psychology is that this narrative self is inherently social: When we construct our lives, we do so in a real or imagined interaction. This predicts that self-referential processes which are involved in recall of autobiographical memories overlap with processes involved in social interactions. Indeed, previous functional MRI studies indicate that regions in the medial prefrontal cortex (mPFC are activated during autobiographical memory recall and virtual communication. However, no fMRI study has investigated recall of autobiographical memories in a real-life interaction. We developed a novel paradigm in which participants overtly reported self-related and other-related memories to an experimenter, whose non-verbal reactions were being filmed and online displayed to the participants in the scanner. We found that recall of autobiographical vs. non-autobiographical memories was associated with activation of the mPFC, as was recall in the social as compared to a non-social control condition; however, both contrasts involved different non-overlapping regions within the mPFC. These results indicate that self-referential processes involved in autobiographical memory recall are different from processes supporting social interactions, and argue against the hypothesis that autobiographical memories are inherently social.

  17. Worldwide advanced nuclear power reactors with passive and inherent safety: What, why, how, and who

    International Nuclear Information System (INIS)

    Forsberg, C.W.; Reich, W.J.

    1991-09-01

    The political controversy over nuclear power, the accidents at Three Mile Island (TMI) and Chernobyl, international competition, concerns about the carbon dioxide greenhouse effect and technical breakthroughs have resulted in a segment of the nuclear industry examining power reactor concepts with PRIME safety characteristics. PRIME is an acronym for Passive safety, Resilience, Inherent safety, Malevolence resistance, and Extended time after initiation of an accident for external help. The basic ideal of PRIME is to develop power reactors in which operator error, internal sabotage, or external assault do not cause a significant release of radioactivity to the environment. Several PRIME reactor concepts are being considered. In each case, an existing, proven power reactor technology is combined with radical innovations in selected plant components and in the safety philosophy. The Process Inherent Ultimate Safety (PIUS) reactor is a modified pressurized-water reactor, the Modular High Temperature Gas-Cooled Reactor (MHTGR) is a modified gas-cooled reactor, and the Advanced CANDU Project is a modified heavy-water reactor. In addition to the reactor concepts, there is parallel work on super containments. The objective is the development of a passive ''box'' that can contain radioactivity in the event of any type of accident. This report briefly examines: why a segment of the nuclear power community is taking this new direction, how it differs from earlier directions, and what technical options are being considered. A more detailed description of which countries and reactor vendors have undertaken activities follows. 41 refs

  18. Inherent Immunogenicity or Lack Thereof of Pluripotent Stem Cells: Implications for Cell Replacement Therapy

    Directory of Open Access Journals (Sweden)

    Arvind Chhabra

    2017-08-01

    Full Text Available Donor-specific induced pluripotent stem cells (iPSCs offer opportunities for personalized cell replacement therapeutic approaches due to their unlimited self-renewal potential and ability to differentiate into different somatic cells. A significant progress has been made toward generating iPSC lines that are free of integrating viral vectors, development of xeno-free culture conditions, and differentiation of pluripotent stem cells (PSCs into functional somatic cell lineages. Since donor-specific iPSC lines are genetically identical to the individual, they are expected to be immunologically matched and these iPSC lines and their cellular derivatives are not expected to be immunologically rejected. However, studies in mouse models, utilizing rejection of teratomas as a model, have claimed that syngenic iPSC lines, especially the iPSC lines derived with integrating viral vectors, could be inherently immunogenic. This manuscript reviews current understanding of inherent immunogenicity of PSC lines, especially that of the human iPSC lines and their cellular derivatives, and strategies to overcome it.

  19. Indispensable role of biochar-inherent mineral constituents in its environmental applications: A review.

    Science.gov (United States)

    Xu, Xiaoyun; Zhao, Yinghao; Sima, Jingke; Zhao, Ling; Mašek, Ondřej; Cao, Xinde

    2017-10-01

    Biochar typically consists of both carbon and mineral fractions, and the carbon fraction has been generally considered to determine its properties and applications. Recently, an increasing body of research has demonstrated that mineral components inherent in biochar, such as alkali or alkaline earth metals in the form of carbonates, phosphates, or oxides, could also influence the properties and thus the applications. The review articles published thus far have mainly focused on multiple environmental and agronomic applications of biochar, including carbon sequestration, soil improvement, environmental remediation, etc. This review aims to highlight the indispensable role of the mineral fraction of biochar in these different applications, especially in environmental applications. Specifically, it provides a critical review of current research findings related to the mineral composition of biochar and the effect of the mineral fraction on the physicochemical properties, contaminant sorption, carbon retention and stability, and nutrient bioavailability of biochar. Furthermore, the role of minerals in the emerging applications of biochar, as a precursor for fuel cells, supercapacitors, and photoactive components, is also summarized. Overall, inherent minerals should be fully considered while determining the most appropriate application for any given biochar. A thorough understanding of the role of biochar-bound minerals in different applications will also allow the design or selection of the most suitable biochar for specific applications based on the consideration of feedstock composition, production parameters, and post-treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. INHERENT ASPECT: A SOCIOFUNCTIONALIST APPROACH OF PAST IMPERFECTIVE VERBAL FORMS IN SPANISH

    Directory of Open Access Journals (Sweden)

    Márluce Coan

    2014-03-01

    Full Text Available : We deal with the category aspect in a lexical dimension – an inherent aspect - and its interaction with the grammatical aspect, in order to inquire the convergences and divergences in the compositional shaping of the aspect. Our data come from twenty four short stories written in Spanish language, selected based on the cultural region parameter: Caribe; Mexico and Central America; Andes, Rio of the Prata; Chile and Spain. It was obtained a total of 2.093 data: 290 of them are imperfective periphrasis of past, that is, 13,85% of the total. These forms encode variably the descriptive, narrative, habitual and desiderative functions. The other identified functions – interactive, politeness, present, future, simultaneity, contrariety and playful – were only encoded by the imperfective past tense. The analysis of the correlation between the inherent aspect and the grammatical one corroborates the range of imperfectiviness by Givón (2001, which issupported by criteria of Vendler’s typology (2005 [1967]: states, the ones less marked and predicable, present more occurrences; followed at scale by activities, culminated processes, and culminations, the ones which are more marked and less predictable.

  1. INHERENT ASPECT: A SOCIOFUNCTIONALIST APPROACH OF PAST IMPERFECTIVE VERBAL FORMS IN SPANISH

    Directory of Open Access Journals (Sweden)

    Márluce COAN

    2013-12-01

    Full Text Available We deal with the category aspect in a lexical dimension – an inherent aspect - and its interaction with the grammatical aspect, in order to inquire the convergences and divergences in the compositional shaping of the aspect. Our data come from twenty four short stories written in Spanish language, selected based on the cultural region parameter: Caribe; Mexico and Central America; Andes, Rio of the Prata; Chile and Spain. It was obtained a total of 2.093 data: 290 of them are imperfective periphrasis of past, that is, 13,85% of the total. These forms encode variably the descriptive, narrative, habitual and desiderative functions. The other identified functions – interactive, politeness, present, future, simultaneity, contrariety and playful – were only encoded by the imperfective past tense. The analysis of the correlation between the inherent aspect and the grammatical one corroborates the range of imperfectiviness by Givón (2001, which issupported by criteria of Vendler’s typology (2005 [1967]: states, the ones less marked and predicable, present more occurrences; followed at scale by activities, culminated processes, and culminations, the ones which are more marked and less predictable.

  2. Optimal control of quantum systems: Origins of inherent robustness to control field fluctuations

    International Nuclear Information System (INIS)

    Rabitz, Herschel

    2002-01-01

    The impact of control field fluctuations on the optimal manipulation of quantum dynamics phenomena is investigated. The quantum system is driven by an optimal control field, with the physical focus on the evolving expectation value of an observable operator. A relationship is shown to exist between the system dynamics and the control field fluctuations, wherein the process of seeking optimal performance assures an inherent degree of system robustness to such fluctuations. The presence of significant field fluctuations breaks down the evolution of the observable expectation value into a sequence of partially coherent robust steps. Robustness occurs because the optimization process reduces sensitivity to noise-driven quantum system fluctuations by taking advantage of the observable expectation value being bilinear in the evolution operator and its adjoint. The consequences of this inherent robustness are discussed in the light of recent experiments and numerical simulations on the optimal control of quantum phenomena. The analysis in this paper bodes well for the future success of closed-loop quantum optimal control experiments, even in the presence of reasonable levels of field fluctuations

  3. Inherent safety features of the HTTR revealed in the accident condition

    International Nuclear Information System (INIS)

    Kunitomi, K.; Shinozaki, M.; Baba, O.; Saito, S.

    1992-01-01

    The High Temperature Engineering Test Reactor (HTTR) being constructed by JAERI (Japan Atomic Energy Research Institute) is a graphite-moderated and helium-cooled reactor with an outlet gas temperature of 950degC. The inherent safety characteristics in the HTTR prevent temperature increase of reactor fuels and fission product release from the reactor core in postulated accident conditions. The reactor core can be cooled by a Vessel Cooling System (VCS) indirectly, even in the case that no forced cooling is expected during the accident such as primary pipe break. The VCS consists of independent water cooling loop and cooling panel around the reactor pressure vessel. The cooling panel whose temperature of 60-90degC cools the reactor pressure vessel by radiation and removes the decay heat from the core indirectly. Furthermore, even if failure of VCS is assumed during this accident as a severe accident, the reactor core is remained safe despite the temperature increase of biological concrete shield around the reactor pressure vessel. This paper describes the inherent safety features of the HTTR specially focused on the accident condition without forced cooling. The detailed analytical results of such an accident are described together with clarifying the role of the VCS. (author)

  4. Dealing with uncertainty and pursuing superior technology options in risk management-The inherency risk analysis

    International Nuclear Information System (INIS)

    Helland, Aasgeir

    2009-01-01

    Current regulatory systems focus on the state of scientific evidence as the predominant factor for how to handle risks to human health and the environment. However, production and assessment of risk information are costly and time-consuming, and firms have an intrinsic disincentive to produce and distribute information about risks of their products as this could endanger their production opportunities and sales. An emphasis on more or better science may result in insufficient thought and attention going into the exploration of technology alternatives, and that risk management policies miss out on the possible achievement of a more favorable set of consequences. In this article, a method is proposed that combines risk assessment with the search for alternative technological options as a part of the risk management procedure. The method proposed is the inherency risk analysis where the first stage focuses on the original agent subject to investigation, the second stage focuses on identifying technological options whereas the third stage reviews the different alternatives, searching for the most attractive tradeoffs between costs and inherent safety. This is then used as a fundament for deciding which technology option to pursue. This method aims at providing a solution-focused, systematic technology-based approach for addressing and setting priorities for environmental problems. By combining risk assessment with a structured approach to identify superior technology options within a risk management system, the result could very well be a win-win situation for both company and the environment.

  5. The development of an inherent safety approach to the prevention of domino accidents.

    Science.gov (United States)

    Cozzani, Valerio; Tugnoli, Alessandro; Salzano, Ernesto

    2009-11-01

    The severity of industrial accidents in which a domino effect takes place is well known in the chemical and process industry. The application of an inherent safety approach for the prevention of escalation events leading to domino accidents was explored in the present study. Reference primary scenarios were analyzed and escalation vectors were defined. Inherent safety distances were defined and proposed as a metric to express the intensity of the escalation vectors. Simple rules of thumb were presented for a preliminary screening of these distances. Swift reference indices for layout screening with respect to escalation hazard were also defined. Two case studies derived from existing layouts of oil refineries were selected to understand the potentialities coming from the application in the methodology. The results evidenced that the approach allows a first comparative assessment of the actual domino hazard in a layout, and the identification of critical primary units with respect to escalation events. The methodology developed also represents a useful screening tool to identify were to dedicate major efforts in the design of add-on measures, optimizing conventional passive and active measures for the prevention of severe domino accidents.

  6. Synthesis and Characterization of Pure Copper Nanostructures Using Wood Inherent Architecture as a Natural Template

    Science.gov (United States)

    Dong, Youming; Wang, Kaili; Tan, Yi; Wang, Qingchun; Li, Jianzhang; Mark, Hughes; Zhang, Shifeng

    2018-04-01

    The inherent sophisticated structure of wood inspires researchers to use it as a natural template for synthesizing functional nanoparticles. In this study, pure copper nanoparticles were synthesized using poplar wood as a natural inexpensive and renewable template. The crystal structure and morphologies of the copper nanoparticles were characterized by X-ray diffraction and field emission scanning electron microscopy. The optical properties, antibacterial properties, and stability of the hybrid wood materials were also tested. Due to the hierarchical and anisotropic structure and electron-rich components of wood, pure copper nanoparticles with high stability were synthesized with fcc structure and uniform sizes and then assembled into corncob-like copper deposits along the wood cell lumina. The products of nanoparticles depended strongly on the initial OH- concentration. With an increase in OH- concentration, Cu2O gradually decreased and Cu remained. Due to the restrictions inherent in wood structure, the derived Cu nanoparticles showed similar grain size in spite of increased Cu2+ concentration. This combination of Cu nanostructures and wood exhibited remarkable optical and antibacterial properties.

  7. Effective material parameter retrieval of anisotropic elastic metamaterials with inherent nonlocality

    Science.gov (United States)

    Lee, Hyung Jin; Lee, Heung Son; Ma, Pyung Sik; Kim, Yoon Young

    2016-09-01

    In this paper, the scattering (S-) parameter retrieval method is presented specifically for anisotropic elastic metamaterials; so far, no retrieval has been accomplished when elastic metamaterials exhibit fully anisotropic behavior. Complex constitutive property and intrinsic scattering behavior of elastic metamaterials make their characterization far more complicated than that for acoustic and electromagnetic metamaterials. In particular, elastic metamaterials generally exhibit anisotropic scattering behavior due to higher scattering modes associated with shear deformation. They also exhibit nonlocal responses to some degrees, which originate from strong multiple scattering interactions even in the long wavelength limit. Accordingly, the conventional S-parameter retrieval methods cannot be directly used for elastic metamaterials, because they determine only the diagonal components in effective tensor property. Also, the conventional methods simply use the analytic inversion formulae for the material characterization so that inherent nonlocality cannot be taken into account. To establish a retrieval method applicable to anisotropic elastic metamaterials, we propose an alternative S-parameter method to deal with full anisotropy of elastic metamaterials. To retrieve the whole effective anisotropic parameter, we utilize not only normal but also oblique wave incidences. For the retrieval, we first retrieve the ratio of the effective stiffness tensor to effective density and then determine the effective density. The proposed retrieval method is validated by characterizing the effective material parameters of various types of non-resonant anisotropic metamaterials. It is found that the whole effective parameters are retrieved consistently regardless of used retrieval conditions in spite of inherent nonlocality.

  8. Theoretical Issues

    Energy Technology Data Exchange (ETDEWEB)

    Marc Vanderhaeghen

    2007-04-01

    The theoretical issues in the interpretation of the precision measurements of the nucleon-to-Delta transition by means of electromagnetic probes are highlighted. The results of these measurements are confronted with the state-of-the-art calculations based on chiral effective-field theories (EFT), lattice QCD, large-Nc relations, perturbative QCD, and QCD-inspired models. The link of the nucleon-to-Delta form factors to generalized parton distributions (GPDs) is also discussed.

  9. Transmission issues

    International Nuclear Information System (INIS)

    Bradford, J.; Wilson, L.; Thon, S.; Millar, N.

    2005-01-01

    This session on transmission issues focused on the role that transmission plays in electricity markets and the importance of getting the market structure right in terms of generation divestiture with buy back contracts, demand side responsive programs, transmission upgrades and long term contracts. The difficulties of distinguishing between market power and scarcity were examined along with some of the complications that ensue if transmission experiences congestion, as exemplified by the August 2003 blackout in eastern North America. The presentations described the best ways to handle transmission issues, and debated whether transmission should be deregulated or follow market forces. Issues of interconnections and reliability of connections were also debated along with the attempt to integrate renewables into the grid. Some presentations identified what new transmission must be built and what must be done to ensure that transmission gets built. The challenges and business opportunities for transmission in Alberta were discussed with reference to plans to invest in new infrastructure, where it is going outside of the province and how it works with other jurisdictions. Manitoba's Conawapa Hydro Project and its 2000 MW tie line to Ontario was also discussed. Some examples of non-optimal use of interconnections in Europe were also discussed in an effort to learn from these mistakes and avoid them in Canada. tabs., figs

  10. Miscellaneous issues

    International Nuclear Information System (INIS)

    2002-01-01

    The New Brunswick Market Design Committee has examined several issues regarding the restructuring of the province's electricity sector. This report presents issues that require guidance for implementation, with particular focus on options available for their resolutions. The issues include: (1) rate principles for stranded offer service (SOS) supply, (2) the ability of contestable customers to return to SOS after having left it, (3) whether loads embedded in distribution systems are eligible to participate in the bilateral contract market, (4) whether generators or suppliers can offer capacity and energy to SOS suppliers in competition with the SOS supplier, and (5) details for the balancing market, including pricing, bidding protocols, settlements and how intermittent power sources can participate in the market. A section on pricing for SOS explains pricing principles, the use of export profits, pricing for SOS capacity, and time of use pricing. The Committee has made recommendations for the electricity system in the province to have an energy imbalance service that can move towards a market in order to develop an efficient and effective service. This report also explains pricing in the balancing market, penalties, and settlements. 7 refs

  11. Safety assessment in plant layout design using indexing approach: implementing inherent safety perspective. Part 1 - guideword applicability and method description.

    Science.gov (United States)

    Tugnoli, Alessandro; Khan, Faisal; Amyotte, Paul; Cozzani, Valerio

    2008-12-15

    Layout planning plays a key role in the inherent safety performance of process plants since this design feature controls the possibility of accidental chain-events and the magnitude of possible consequences. A lack of suitable methods to promote the effective implementation of inherent safety in layout design calls for the development of new techniques and methods. In the present paper, a safety assessment approach suitable for layout design in the critical early phase is proposed. The concept of inherent safety is implemented within this safety assessment; the approach is based on an integrated assessment of inherent safety guideword applicability within the constraints typically present in layout design. Application of these guidewords is evaluated along with unit hazards and control devices to quantitatively map the safety performance of different layout options. Moreover, the economic aspects related to safety and inherent safety are evaluated by the method. Specific sub-indices are developed within the integrated safety assessment system to analyze and quantify the hazard related to domino effects. The proposed approach is quick in application, auditable and shares a common framework applicable in other phases of the design lifecycle (e.g. process design). The present work is divided in two parts: Part 1 (current paper) presents the application of inherent safety guidelines in layout design and the index method for safety assessment; Part 2 (accompanying paper) describes the domino hazard sub-index and demonstrates the proposed approach with a case study, thus evidencing the introduction of inherent safety features in layout design.

  12. European Constitutional Identity “Inside Out”: Inherent Risks of the Pluralist Structure

    DEFF Research Database (Denmark)

    Cebulak, Pola Paula

    2012-01-01

    The jurisprudence of the CJEU and the national constitutional courts referring to the national constitutional identities of the Members States fits into the framework of constitutional pluralism as modus vivendi of the European legal order. This paper focuses in particular on the recent judgments...... the tensions inherent in the pluralist structure of the relationships between legal orders in the European arena. Constitutional identity is yet another concept used in this debate about the ultimate authority. Pluralism assumes that the courts will compete over the ultimate authority and will try to use...... for fruitful interaction of competing visions of Europe. Single criticisable judgments do not put in question the viability of the whole framework, but it is important to be aware of the systemic risks....

  13. Evaluation of design variants for improved inherent regulation of advanced small modular reactors - 15325

    International Nuclear Information System (INIS)

    Vilim, R.B.; Passerini, S.

    2015-01-01

    This paper examines design variants that can improve inherent regulation in Advanced Small Modular Reactors (ASMR). It looks at the nature of unprotected upsets and then develops appropriate design measures to ensure that no upset can override a capability for safe self-regulation. This work adopts a reference sodium fast reactor (SFR) design to serve as a baseline for operational and safety performance and for comparison with variants on this design. The effect of design measures on plant stability is then examined. It is found that compared to full-power operation, the stability margin is reduced under islanded-operation. Islanded-operation is more likely for an ASMR deployed in a small regional electric grid with high penetration of renewable energy sources. The stability of core power production is a function of the inlet temperature coefficient, coolant transport times, and temperature-front attenuation in heat exchangers. The interaction of these phenomena with the control system is described

  14. Design of a Single Motor Based Leg Structure with the Consideration of Inherent Mechanical Stability

    Science.gov (United States)

    Taha Manzoor, Muhammad; Sohail, Umer; Noor-e-Mustafa; Nizami, Muhammad Hamza Asif; Ayaz, Yasar

    2017-07-01

    The fundamental aspect of designing a legged robot is constructing a leg design that is robust and presents a simple control problem. In this paper, we have successfully designed a robotic leg based on a unique four bar mechanism with only one motor per leg. The leg design parameters used in our platform are extracted from design principles used in biological systems, multiple iterations and previous research findings. These principles guide a robotic leg to have minimal mechanical passive impedance, low leg mass and inertia, a suitable foot trajectory utilizing a practical balance between leg kinematics and robot usage, and the resultant inherent mechanical stability. The designed platform also exhibits the key feature of self-locking. Theoretical tools and software iterations were used to derive these practical features and yield an intuitive sense of the required leg design parameters.

  15. Utopia and Debt in Postmodernity; or, Time Management in Inherent Vice

    Directory of Open Access Journals (Sweden)

    James Liner

    2016-05-01

    Full Text Available The category of postmodernism has come under renewed scrutiny in recent years. Indeed, it has become rather commonplace to pronounce the death or obsolescence of postmodernism today. Unsurprisingly, the increasingly questioned status of postmodernism also impacts the field of Pynchon studies. This article reads 'Inherent Vice' as symptomatic not of the end but of a transformation of postmodernism and postmodernity. Pynchon’s novel simultaneously registers a contemporary intensification of postmodern/late capitalism and, crucially, participates in a minor current in postmodernism, one which insists on collective agency and utopian thinking despite the atomization and isolation of subjects accomplished by late capitalism and which, against all odds, remembers how to think historically—or better, invents new ways of thinking historically.

  16. Comments on the variability of inherent bioelement contents of spruce needles

    International Nuclear Information System (INIS)

    Wyttenbach, A.; Tobler, L.; Bajo, S.

    1991-01-01

    Inherent needle contents are the relevant concentrations within the needle, excluding surface contaminations by aerosols. The error arising from the analysis of unwashed needles is quantified. For many elements it is the source of a large apparent variability. Spatial variability is discussed under the aspects of variability among trees within a plot and of variability among different plots. Both terms have implications as to the number of trees that should be sampled for the characterization of a plot. Variability with time is investigated by following the needle concentrations from an age of 1 to 23 months. The results give indications on favourable sampling dates and on the physiology of the different elements. All investigations refer to 20 elements, which have been determined by neutron activation analysis. (author) 6 figs., 5 tabs., 16 refs

  17. A level III PSA for the inherently safe CAREM-25 nuclear power station

    International Nuclear Information System (INIS)

    Baron, Jorge H.; Nunez McLeod, J.; Rivera, S.S.

    2000-01-01

    A Level III PSA has been performed for the inherently safe CAREM-25 nuclear power station, as a requirement for licensing according to argentinian regulations. The CAREM-25 project is still at a detailed design state, therefore only internal events have been considered, and a representative site has been assumed for dose estimations. Several conservative hypothesis have been formulated, but even so an overall core melt frequency of 2.3E -5 per reactor year has been obtained. The risk estimations comply with the regulations. The risk values obtained are compared to the 700MW(e) nuclear power plant Atucha II PSA result, showing an effective risk reduction not only in the severe accident probability but alto in the consequence component of the risk estimation. (author)

  18. Why infest the loved ones--inherent human behaviour indicates former mutualism with head lice.

    Science.gov (United States)

    Rózsa, Lajos; Apari, Péter

    2012-05-01

    Head lice transmit to new hosts when people lean their heads together. Humans frequently touch their heads to express friendship or love, while this behaviour is absent in apes. We hypothesize that this behaviour was adaptive because it enabled people to acquire head lice infestations as early as possible to provoke an immune response effective against both head lice and body lice throughout the subsequent periods of their life. This cross-immunity could provide some defence against the body-louse-borne lethal diseases like epidemic typhus, trench fever, relapsing fever and the classical plague. Thus the human 'touching heads' behaviour probably acts as an inherent and unconscious 'vaccination' against body lice to reduce the threat exposed by the pathogens they may transmit. Recently, the eradication of body-louse-borne diseases rendered the transmission of head lice a maladaptive, though still widespread, behaviour in developed societies.

  19. Inherently safe aircooling for the storage of self-heating configurations of radionuclides

    International Nuclear Information System (INIS)

    Hame, W.; Klein, D.; Pirk, H.

    1980-01-01

    NUKEM developed a technical concept of a radionuclide storage facility based on aircooling, which provides that - the radionuclides, i.e. spent fuel elements, are tightly canned in steel canisters - the canned elements are put into individual cooling channels, which form the storage rack within the storage cell - the produced heat is removed from the surface of the canisters through free convection. This cooling concept shows the following advantages: - The cooling is inherently safe, as the driving force of the coolant is reliably supplied by the heat production of the system to be cooled. - The system is self-controlled and self-regulated because of the physically based correlation of heat production, heat transfer coefficients and air flow resistances. (orig.) 891 RB/orig. 892 MKO [de

  20. Dynamic operator actions analysis for inherently safe fast reactors and light water reactors

    International Nuclear Information System (INIS)

    Ho, V.; Apostolakis, G.

    1988-01-01

    A comparative dynamic human actions analysis of inherently safe fast reactors (ISFRs) and light water reactors (LWRs) in terms of systems response and estimated human error rates is presented. Brief overviews of the ISFR and LWR systems are given to illustrate the design differences. Key operator actions required by the ISFR reactor shutdown and decay heat removal systems are identified and are compared with those of the LWR. It is observed that, because of the passive nature of the ISFR safety-related systems, a large time window is available for operator actions during transient events. Furthermore, these actions are fewer in number, are less complex, and have lower error rates and less severe consequences than those of the LWRs. We expect the ISFR operator errors' contribution to risk is smaller (at least in the context of the existing human reliability models) than that of the LWRs. (author)

  1. Quick and Easy Measurements of the Inherent Optical Property of Water by Laser

    International Nuclear Information System (INIS)

    Izadi, Dina; Hajiesmaeilbaigi, Fereshteh

    2009-01-01

    To generate realistic images of natural waters, one must consider in some detail the interaction of light with the water body. The reflectance and attenuation coefficient of the second harmonic of Nd:YAG laser light through distilled water and a sample of water from the Oman Sea were measured in a solid-state laser laboratory to estimate inherent optical properties of natural waters. These measurements determined the bottom conditions and the impurities of the water. The water's reflectivity varied depending on the angle of incidence, height of the laser from water surface, wavelength of laser light, radiant intensities, and depth of water. In these experiments laser light propagated through the water nonlinearly, and different reflectance showed different bottom slopes. The differences among various water samples were obtained taking into account the exponential equation in attenuation coefficient versus depth graphs.

  2. Evaluation of different in vitro assays of inherent sensitivity as predictors of radiotherapy response

    International Nuclear Information System (INIS)

    Schwartz, J.L.; Chicago Univ., IL; Beckett, M.A.; Mustafi, R.; Weichselbaum, R.R.; Vaughan, A.T.M.

    1991-01-01

    The inherent sensitivity of cells within a tumor plays an important role in the response of the tumor to radiotherapy. Clonogenic assays show that cells established from in-field radiotherapy failures are significantly more resistant to radiation than cell lines established from pre-treatment samples. Clonogenic assays fail to predict tumor response to radiotherapy, however. The failure might be due to the small sample size in this study, or the complicating factors of staging, surgery, and chemotherapy, and/or in vivo selection by radiotherapy for resistant tumor cells. In vitro selection for resistant cell lines does not appear to be a complicating factor. Nonclonogenic assays such as those that measure DNA strand break rejoining rates (filter elution, pulse-field gel electrophoresis) or chromosome structure (flow cytometric analysis) show promise as alternative rapid assays of radiation sensitivity and possibly tumor response. 16 refs., 2 figs

  3. Contrasting Inherent Optical Properties and Carbon Metabolism Between Five Northeastern (USA) Estuary-plume Systems

    Science.gov (United States)

    Vandemark, Doug; Salisbury, Joe; Hunt, Chris; McGillis, Wade R.

    2004-01-01

    We have recently developed the ability to rapidly assess Surface inherent optical properties (IOP), oxygen concentration and pCO2 in estuarine-plume systems using flow-through instrumentation. During the summer of 2004, several estuarine-plume systems were surveyed which include the Pleasant (ME), Penobscot (ME), Kennebec-Androscoggin (ME), Merrimack (NH-MA) and Hudson (NY). Continuous measurements of surface chlorophyll and colored dissolved organic carbon (CDOM) fluorescence, beam attenuation, temperature, salinity, oxygen and pC02 were taken at each system along a salinity gradient from fresh water to near oceanic endmembers. CTD and IOP profiles were also taken at predetermined surface salinity intervals. These were accompanied by discrete determinations of chlorophyll (HPLC and fluorometric), total suspended solids (TSS), dissolved organic carbon (DOC) and alkalinity. IOP data were calibrated using chlorophyll, DOC and TSS data to enable the retrieval of these constituents from IOP data. Considerable differences in the data sets were observed between systems. These ranged from the DOC-enriched, strongly heterotrophic Pleasant River System to the high-chlorophyll autotrophic Merrimack River System. Using pCO2 and oxygen saturation measurements as proxies for water column metabolism, distinct relationships were found between trophic status and inherent optical properties. The nature of these relationships varies between systems and is likely a function of watershed and estuarine attributes including carbon and nutrient loading, in-situ production and related autochthonous inputs of DOC and alkalinity. Our results suggest that IOP data may contain significant information about the trophic status of estuarine and plume systems.

  4. Analysis Relationship Among Descriptor, References and Citation to Contruct the Inherent Structure of Document Collection

    International Nuclear Information System (INIS)

    Hasibuan, Zainal A.; Mustangimah

    2001-01-01

    There are many characteristics can be used to identify a document which cover characteristics of the documents, cited documents, and citing documents This research explored the inherent structure of a document collection as one of main components of information retrieval system. The characteristics examined are: descriptors, references (cited documents), and citations (citing documents). Three independent variables were studied: co-descriptor, bibliographic coupling, and co-citation. A test collection was constructed by searching on a single descriptor i nformation retrieval i n the CD-ROM version of Education Resource Information Clearinghouse (ERIC), covering the period 1981 through 1985. Descriptors were extracted from ERIC; cited and citing documents associated with the test collection were derived from Social Sciences Citation Index (SSCI), covering the period 1981 through 1990. Three hypothesis were tested in this study, that are: (1) the higher the frequency of co-descriptors between documents, the higher the frequencies of their bibliographic coupling and co-citation; (2) the higher the frequency of bibliographic coupling between documents, the higher the frequencies of their co-citation and co-descriptors; and (3) the higher the frequency of co-citation between documents, the higher the frequencies of their co-descriptors and bibliographic coupling. The results showed that all of three hypothesis are supported statistically and there is a significant linear relationship among the observed variables. It is mean that there is a significant relationship among descriptors, references, and citation, so that it can be used to construct the inherent structure of document collection in order to improve information retrieval system performance

  5. Nuclear desalination in the Arab world - Part II: Advanced inherent and passive safe nuclear reactors

    International Nuclear Information System (INIS)

    Karameldin, A.; Samer S. Mekhemar

    2004-01-01

    Rapid increases in population levels have led to greater demands for fresh water and electricity in the Arab World. Different types of energies are needed to contribute to bridging the gap between increased demand and production. Increased levels of safeguards in nuclear power plants have became reliable due to their large operational experience, which now exceeds 11,000 years of operation. Thus, the nuclear power industry should be attracting greater attention. World electricity production from nuclear power has risen from 1.7% in 1970 to 17%-20% today. This ratio had increased in June 2002 to reach more than 30%, 33% and 42% in Europe, Japan, and South Korea respectively. In the Arab World, both the public acceptance and economic viability of nuclear power as a major source of energy are greatly dependent on the achievement of a high level of safety and environmental protection. An assessment of the recent generation of advanced reactor safety criteria requirements has been carried out. The promising reactor designs adapted for the Arab world and other similar developing countries are those that profit from the enhanced and passive safety features of the new generation of reactors, with a stronger focus on the effective use of intrinsic characteristics, simplified plant design, and easy construction, operation and maintenance. In addition, selected advanced reactors with a full spectrum from small to large capacities, and from evolutionary to radical types, which have inherent and passive safety features, are discussed. The relevant economic assessment of these reactors adapted for water/electricity cogeneration have been carried out and compared with non-nuclear desalination methods. This assessment indicates that, water/electricity cogeneration by the nuclear method with advanced inherent and passive safe nuclear power plants, is viable and competitive. (author)

  6. The inherent weaknesses in industrial control systems devices; hacking and defending SCADA systems

    Science.gov (United States)

    Bianco, Louis J.

    The North American Electric Reliability Corporation (NERC) is about to enforce their NERC Critical Infrastructure Protection (CIP) Version Five and Six requirements on July 1st 2016. The NERC CIP requirements are a set of cyber security standards designed to protect cyber assets essential the reliable operation of the electric grid. The new Version Five and Six requirements are a major revision to the Version Three (currently enforced) requirements. The new requirements also bring substations into scope alongside Energy Control Centers. When the Version Five requirements were originally drafted they were vague, causing in depth discussions throughout the industry. The ramifications of these requirements has made owners look at their systems in depth, questioning how much money it will take to meet these requirements. Some owners saw backing down from routable networks to non-routable as a means to save money as they would be held to less requirements within the standards. Some owners saw removing routable connections as a proper security move. The purpose of this research was to uncover the inherent weaknesses in Industrial Control Systems (ICS) devices; to show how ICS devices can be hacked and figure out potential protections for these Critical Infrastructure devices. In addition, this research also aimed to validate the decision to move from External Routable connectivity to Non-Routable connectivity, as a security measure and not as a means of savings. The results reveal in order to ultimately protect Industrial Control Systems they must be removed from the Internet and all bi-directional external routable connections must be removed. Furthermore; non-routable serial connections should be utilized, and these non-routable serial connections should be encrypted on different layers of the OSI model. The research concluded that most weaknesses in SCADA systems are due to the inherent weaknesses in ICS devices and because of these weaknesses, human intervention is

  7. Anomalous baroreflex functionality inherent in floxed and Cre-Lox mice: an overlooked physiological phenotype.

    Science.gov (United States)

    Tsai, Ching-Yi; Poon, Yan-Yuen; Chen, Chang-Han; Chan, Samuel H H

    2017-10-01

    The last two decades have seen the emergence of Cre-Lox recombination as one of the most powerful and versatile technologies for cell-specific genetic engineering of mammalian cells. Understandably, the primary concerns in the practice of Cre-Lox recombination are whether the predicted genome has been correctly modified and the targeted phenotypes expressed. Rarely are the physiological conditions of the animals routinely examined because the general assumption is that they are normal. Based on corroborative results from radiotelemetric recording, power spectral analysis, and magnetic resonance imaging/diffusion tensor imaging in brain-derived neurotrophic factor-floxed mice, the present study revealed that this assumption requires amendment. We found that despite comparable blood pressure and heart rate with C57BL/6 or Cre mice under the conscious state, floxed and Cre-Lox mice exhibited diminished baroreflex-mediated sympathetic vasomotor tone and cardiac vagal baroreflex. We further found that the capacity and plasticity of baroreflex of these two strains of mice under isoflurane anesthesia were retarded, as reflected by reduced connectivity between the nucleus tractus solitarii and rostral ventrolateral medulla or nucleus ambiguus. The identification of anomalous baroreflex functionality inherent in floxed and Cre-Lox mice points to the importance of incorporating physiological phenotypes into studies that engage gene manipulations such as Cre-Lox recombination. NEW & NOTEWORTHY We established that anomalous baroreflex functionality is inherent in floxed and Cre-Lox mice. These two mouse strains exhibited diminished baroreflex-mediated sympathetic vasomotor tone and cardiac vagal baroreflex under the conscious state, retarded capacity and plasticity of baroreflex under isoflurane anesthesia, and reduced connectivity between key nuclei in the baroreflex neural circuits. Copyright © 2017 the American Physiological Society.

  8. Seeds of Brassicaceae weeds have an inherent or inducible response to the germination stimulant karrikinolide.

    Science.gov (United States)

    Long, Rowena L; Stevens, Jason C; Griffiths, Erin M; Adamek, Markus; Gorecki, Marta J; Powles, Stephen B; Merritt, David J

    2011-10-01

    Karrikinolide (KAR(1)) is a smoke-derived chemical that can trigger seeds to germinate. A potential application for KAR(1) is for synchronizing the germination of weed seeds, thereby enhancing the efficiency of weed control efforts. Yet not all species germinate readily with KAR(1), and it is not known whether seemingly non-responsive species can be induced to respond. Here a major agronomic weed family, the Brassicaceae, is used to test the hypothesis that a stimulatory response to KAR(1) may be present in physiologically dormant seeds but may not be expressed under all circumstances. Seeds of eight Brassicaceae weed species (Brassica tournefortii, Raphanus raphanistrum, Sisymbrium orientale, S. erysimoides, Rapistrum rugosum, Lepidium africanum, Heliophila pusilla and Carrichtera annua) were tested for their response to 1 µm KAR(1) when freshly collected and following simulated and natural dormancy alleviation, which included wet-dry cycling, dry after-ripening, cold and warm stratification and a 2 year seed burial trial. Seven of the eight Brassicaceae species tested were stimulated to germinate with KAR(1) when the seeds were fresh, and the remaining species became responsive to KAR(1) following wet-dry cycling and dry after-ripening. Light influenced the germination response of seeds to KAR(1), with the majority of species germinating better in darkness. Germination with and without KAR(1) fluctuated seasonally throughout the seed burial trial. KAR(1) responses are more complex than simply stating whether a species is responsive or non-responsive; light and temperature conditions, dormancy state and seed lot all influence the sensitivity of seeds to KAR(1), and a response to KAR(1) can be induced. Three response types for generalizing KAR(1) responses are proposed, namely inherent, inducible and undetected. Given that responses to KAR(1) were either inherent or inducible in all 15 seed lots included in this study, the Brassicaceae may be an ideal target for

  9. PRISM [Power Reactor Inherently Safe Module] design concept enhances waste management

    International Nuclear Information System (INIS)

    Thompson, M.L.; Berglund, R.C.

    1989-01-01

    PRISM, a modular advanced liquid metal reactor (ALMR), has been designed conceptually by GE under the US Department of Energy sponsorship. The concept design and analyses have been primarily focused on passive safety and improved construction and operating costs. Significantly, the unique design of multiple modules and features of PRISM enhance waste management over conventional reactor systems. This paper provides an overview of PRISM of these enhancements. Inherent to the ALMR's, the sodium coolant precludes crud buildup on reactor surfaces and in components and waste for disposal. Preliminary evaluations indicate this fundamental feature results in factors of 2-4 less waste volume and 2-3 orders of magnitude less curies per megawatt-electric for ultimate disposal. For example, the tap designed for sodium cleanup is expected to be exchanged only once every thirty years. Also, inherent to ALMR's, burning waste actinides and selected fission products to preclude their accumulation and burial is very attractive. The hard neutron spectrum of ALMR burns the actinides efficiently and is not poisoned by the actinides and fission products. The modular design of PRISM components (and the fuel cycle equipment) permit replacement without expensive and potentially hazardous volume reduction. For example, the functional components of the reference electromagnetic pump and IHK can be removed intact for waste disposal. Although development of the reference metal fuel is not completed, it is estimated that (low-level) waste from recycle of the fuel will result in significantly less volume than would be generated by aqueous recycle of oxide fuel. 6 refs., 10 figs

  10. Liability Issues

    International Nuclear Information System (INIS)

    O’Donoghue, K.

    2016-01-01

    Nuclear liability conventions try to provide a set of rules to govern third party liability. Not all States are parties to one of the existing liability conventions. There are a number of reasons why individual States may choose not to join one of the existing conventions. These include limits of compensation, jurisdiction issues, complexity, cost and definition of damage among others. This paper looks at the existing conventions and identifies some of the main issues in the existing conventions which prevent some States from signing them. The paper attempts to tease out some of the perceived gaps in the existing conventions and give a brief description of the reasons why non-Contracting Parties have difficulty with the provisions of the conventions. The paper recognizes that there has been work done in this area previously by the International Expert Group on Nuclear Liability (INLEX) and others to try to develop the existing frameworks to enhance global adherence by nuclear and non-nuclear States to an effective nuclear liability regime. (author)

  11. Licensing issues

    International Nuclear Information System (INIS)

    Roberts, J.P.; Desell, L.J.; Birch, M.L.; Berkowitz, L.; Bader, J.F.

    1992-01-01

    To provide guidance for the Department of Energy's (DOE) Civilian Radioactive Waste Management Program, the Nuclear Regulatory Commission (NRC) has issued a draft regulatory guide on the Format and Content for the License Application for the High-Level Waste Repository (FCRG). To facilitate the development of the FCRG, NRC suggested that DOE use the draft guide as the basis for preparing an annotated outline for a license application. DOE is doing so using an iterative process called the Annotated Outline Initiative. DOE;s use of the Initiative will assist in achieving the desired incorporation of actual experience in the FCRG, contribute to the development of shared interpretation and understanding of NRC regulations, and provide other important programmatic benefits described in this paper

  12. Design of a mutual authentication based on NTRUsign with a perturbation and inherent multipoint control protocol frames in an Ethernet-based passive optical network

    Science.gov (United States)

    Yin, Aihan; Ding, Yisheng

    2014-11-01

    Identity-related security issues inherently present in passive optical networks (PON) still exist in the current (1G) and next-generation (10G) Ethernet-based passive optical network (EPON) systems. We propose a mutual authentication scheme that integrates an NTRUsign digital signature algorithm with inherent multipoint control protocol (MPCP) frames over an EPON system between the optical line terminal (OLT) and optical network unit (ONU). Here, a primitive NTRUsign algorithm is significantly modified through the use of a new perturbation so that it can be effectively used for simultaneously completing signature and authentication functions on the OLT and the ONU sides. Also, in order to transmit their individual sensitive messages, which include public key, signature, and random value and so forth, to each other, we redefine three unique frames according to MPCP format frame. These generated messages can be added into the frames and delivered to each other, allowing the OLT and the ONU to go ahead with a mutual identity authentication process to verify their legal identities. Our simulation results show that this proposed scheme performs very well in resisting security attacks and has low influence on the registration efficiency to to-be-registered ONUs. A performance comparison with traditional authentication algorithms is also presented. To the best of our knowledge, no detailed design of mutual authentication in EPON can be found in the literature up to now.

  13. The nature of inherent bactericidal activity: insights from the nanotopology of three species of dragonfly

    Science.gov (United States)

    Mainwaring, David E.; Nguyen, Song Ha; Webb, Hayden; Jakubov, Timur; Tobin, Mark; Lamb, Robert N.; Wu, Alex H.-F.; Marchant, Richard; Crawford, Russell J.; Ivanova, Elena P.

    2016-03-01

    While insect wings are widely recognised as multi-functional, recent work showed that this extends to extensive bactericidal activity brought about by cell deformation and lysis on the wing nanotopology. We now quantitatively show that subtle changes to this topography result in substantial changes in bactericidal activity that are able to span an order of magnitude. Notably, the chemical composition of the lipid nanopillars was seen by XPS and synchrotron FTIR microspectroscopy to be similar across these activity differences. Modelling the interaction between bacterial cells and the wing surface lipids of 3 species of dragonflies, that inhabit similar environments, but with distinctly different behavioural repertoires, provided the relationship between surface structure and antibacterial functionality. In doing so, these principal behavioural patterns correlated with the demands for antimicrobial efficiency dictated by differences in their foraging strategies. This work now reveals a new feature in the design elegance of natural multi-functional surfaces as well providing insights into the bactericidal mechanism underlying inherently antimicrobial materials, while suggesting that nanotopology is related to the evolutionary development of a species through the demands of its behavioural repertoire. The underlying relationship between the processes of wetting, adhesion and capillarity of the lipid nanopillars and bactericidal efficiency suggests new prospects for purely mechano-responsive antibacterial surfaces.While insect wings are widely recognised as multi-functional, recent work showed that this extends to extensive bactericidal activity brought about by cell deformation and lysis on the wing nanotopology. We now quantitatively show that subtle changes to this topography result in substantial changes in bactericidal activity that are able to span an order of magnitude. Notably, the chemical composition of the lipid nanopillars was seen by XPS and synchrotron

  14. Dissociable Changes of Frontal and Parietal Cortices in Inherent Functional Flexibility across the Human Life Span.

    Science.gov (United States)

    Yin, Dazhi; Liu, Wenjing; Zeljic, Kristina; Wang, Zhiwei; Lv, Qian; Fan, Mingxia; Cheng, Wenhong; Wang, Zheng

    2016-09-28

    Extensive evidence suggests that frontoparietal regions can dynamically update their pattern of functional connectivity, supporting cognitive control and adaptive implementation of task demands. However, it is largely unknown whether this flexibly functional reconfiguration is intrinsic and occurs even in the absence of overt tasks. Based on recent advances in dynamics of resting-state functional resonance imaging (fMRI), we propose a probabilistic framework in which dynamic reconfiguration of intrinsic functional connectivity between each brain region and others can be represented as a probability distribution. A complexity measurement (i.e., entropy) was used to quantify functional flexibility, which characterizes heterogeneous connectivity between a particular region and others over time. Following this framework, we identified both functionally flexible and specialized regions over the human life span (112 healthy subjects from 13 to 76 years old). Across brainwide regions, we found regions showing high flexibility mainly in the higher-order association cortex, such as the lateral prefrontal cortex (LPFC), lateral parietal cortex, and lateral temporal lobules. In contrast, visual, auditory, and sensory areas exhibited low flexibility. Furthermore, we observed that flexibility of the right LPFC improved during maturation and reduced due to normal aging, with the opposite occurring for the left lateral parietal cortex. Our findings reveal dissociable changes of frontal and parietal cortices over the life span in terms of inherent functional flexibility. This study not only provides a new framework to quantify the spatiotemporal behavior of spontaneous brain activity, but also sheds light on the organizational principle behind changes in brain function across the human life span. Recent neuroscientific research has demonstrated that the human capability of adaptive task control is primarily the result of the flexible operation of frontal brain networks. However

  15. No inherent left and right side in human 'mental number line': evidence from right brain damage.

    Science.gov (United States)

    Aiello, Marilena; Jacquin-Courtois, Sophie; Merola, Sheila; Ottaviani, Teresa; Tomaiuolo, Francesco; Bueti, Domenica; Rossetti, Yves; Doricchi, Fabrizio

    2012-08-01

    Spatial reasoning has a relevant role in mathematics and helps daily computational activities. It is widely assumed that in cultures with left-to-right reading, numbers are organized along the mental equivalent of a ruler, the mental number line, with small magnitudes located to the left of larger ones. Patients with right brain damage can disregard smaller numbers while mentally setting the midpoint of number intervals. This has been interpreted as a sign of spatial neglect for numbers on the left side of the mental number line and taken as a strong argument for the intrinsic left-to-right organization of the mental number line. Here, we put forward the understanding of this cognitive disability by discovering that patients with right brain damage disregard smaller numbers both when these are mapped on the left side of the mental number line and on the right side of an imagined clock face. This shows that the right hemisphere supports the representation of small numerical magnitudes independently from their mapping on the left or the right side of a spatial-mental layout. In addition, the study of the anatomical correlates through voxel-based lesion-symptom mapping and the mapping of lesion peaks on the diffusion tensor imaging-based reconstruction of white matter pathways showed that the rightward bias in the imagined clock-face was correlated with lesions of high-level middle temporal visual areas that code stimuli in object-centred spatial coordinates, i.e. stimuli that, like a clock face, have an inherent left and right side. In contrast, bias towards higher numbers on the mental number line was linked to white matter damage in the frontal component of the parietal-frontal number network. These anatomical findings show that the human brain does not represent the mental number line as an object with an inherent left and right side. We conclude that the bias towards higher numbers in the mental bisection of number intervals does not depend on left side spatial

  16. Handbook of critical issues in goal programming

    CERN Document Server

    Romero, C

    1991-01-01

    Goal Programming (GP) is perhaps the oldest and most widely used approach within the Multiple Criteria Decision Making (MCDM) paradigm. GP combines the logic of optimisation in mathematical programming with the decision maker's desire to satisfy several goals. The primary purpose of this book is to identify the critical issues in GP and to demonstrate different procedures capable of avoiding or mitigating the inherent pitfalls associated with these issues. The outcome of a search of the literature shows many instances where GP models produced misleading or even erroneous results simply because

  17. Transitional issues

    International Nuclear Information System (INIS)

    1998-01-01

    This discussion paper, the fifth in the series developed at the IPPSO Market Design Conference, addressed the issue of the need to prevent Ontario Hydro from taking unfair advantage of independent producers and other stakeholders through activities and investments in new power generating capacity in the transitional period leading up to deregulation. The need for controls is predicated on the assumption that the short-term actions and investments of Ontario Hydro could seriously compromise the position of independent generators, and that without such controls the level playing field essential to the operation of a competitive market, does not exist. Various actual and potential actions of Ontario Hydro were discussed, all of which point to the need for strict controls over Ontario Hydro exercising its dominant market power in an unfair way. It was recommended that as a minimum, the provincial government should no longer provide guarantees for Ontario Hydro capital projects, and that Ontario Hydro be instructed to defer any investment on new or returning generating capacity until the new market is in place. Limits could also be placed on Ontario Hydro's marketing efforts to enter into contracts during the transition period, and Ontario Hydro and municipal utilities should be required to keep separate accounts of their commercial preparation, and to settle such accounts separate from ratepayer revenue

  18. Underwater Inherent Optical Properties Estimation Using a Depth Aided Deep Neural Network

    Directory of Open Access Journals (Sweden)

    Zhibin Yu

    2017-01-01

    Full Text Available Underwater inherent optical properties (IOPs are the fundamental clues to many research fields such as marine optics, marine biology, and underwater vision. Currently, beam transmissometers and optical sensors are considered as the ideal IOPs measuring methods. But these methods are inflexible and expensive to be deployed. To overcome this problem, we aim to develop a novel measuring method using only a single underwater image with the help of deep artificial neural network. The power of artificial neural network has been proved in image processing and computer vision fields with deep learning technology. However, image-based IOPs estimation is a quite different and challenging task. Unlike the traditional applications such as image classification or localization, IOP estimation looks at the transparency of the water between the camera and the target objects to estimate multiple optical properties simultaneously. In this paper, we propose a novel Depth Aided (DA deep neural network structure for IOPs estimation based on a single RGB image that is even noisy. The imaging depth information is considered as an aided input to help our model make better decision.

  19. Simple frequency-dependent tools for analysis of inherent control limitations

    Directory of Open Access Journals (Sweden)

    Sigurd Skogestad

    1991-10-01

    Full Text Available By a plant's inherent control limitations we mean the characteristics of the plant which will cause poor control performance irrespective of what controller is used. Another frequently used term is 'dynamic resilience' which is the best closed-loop performance achievable using any controller. Since a plant's dynamic resilience cannot be altered by change of the control algorithm, but only by design modifications, it follows that the term controllability provides a link between process design and process control. In this paper we focus on two aspects of controllability. The plants' sensitivity to disturbances and the limitations imposed by interactions when using decentralized control. We use simple tools such as the RGA, the PRGA (Performance RGA and the closely related Closed Loop Disturbance Gain (CLDG. For example, if kth column of the CLDG is large, then this indicates that disturbance k will be difficult to reject. This may pinpoint the need for modifying the process. The PRGA provides a measure of interaction which also includes one-way coupling. In the paper we apply these measures to distillation column control and fluid catalytic cracker (FCC control.

  20. Distinct Short-Range Order Is Inherent to Small Amorphous Calcium Carbonate Clusters (<2 nm)

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Shengtong [Physical Chemistry, University of Konstanz, Universitätsstrasse 10 78457 Konstanz Germany; School of Chemical Engineering, State Key Laboratory of Chemical Engineering, Shanghai Key Laboratory of Multiphase Materials Chemical Engineering, East China University of Science and Technology, 130 Meilong Road Shanghai 200237 P.R. China; Chevrier, Daniel M. [Department of Chemistry and Institute for Research in Materials, Dalhousie University, Halifax Nova Scotia B3H 4R2 Canada; Zhang, Peng [Department of Chemistry and Institute for Research in Materials, Dalhousie University, Halifax Nova Scotia B3H 4R2 Canada; Gebauer, Denis [Physical Chemistry, University of Konstanz, Universitätsstrasse 10 78457 Konstanz Germany; Cölfen, Helmut [Physical Chemistry, University of Konstanz, Universitätsstrasse 10 78457 Konstanz Germany

    2016-09-09

    Amorphous intermediate phases are vital precursors in the crystallization of many biogenic minerals. While inherent short-range orders have been found in amorphous calcium carbonates (ACCs) relating to different crystalline forms, it has never been clarified experimentally whether such orders already exist in very small clusters less than 2 nm in size. Here, we studied the stability and structure of 10,12-pentacosadiynoic acid (PCDA) protected ACC clusters with a core size of ca. 1.4 nm consisting of only seven CaCO3 units. Ligand concentration and structure are shown to be key factors in stabilizing the ACC clusters. More importantly, even in such small CaCO3 entities, a proto-calcite short-range order can be identified but with a relatively high degree of disorder that arises from the very small size of the CaCO3 core. Our findings support the notion of a structural link between prenucleation clusters, amorphous intermediates, and final crystalline polymorphs, which appears central to the understanding of polymorph selection.

  1. A Mechanistic Reliability Assessment of RVACS and Metal Fuel Inherent Reactivity Feedbacks

    Energy Technology Data Exchange (ETDEWEB)

    Grabaskas, David; Brunett, Acacia J.; Passerini, Stefano; Grelle, Austin

    2017-09-24

    GE Hitachi Nuclear Energy (GEH) and Argonne National Laboratory (Argonne) participated in a two year collaboration to modernize and update the probabilistic risk assessment (PRA) for the PRISM sodium fast reactor. At a high level, the primary outcome of the project was the development of a next-generation PRA that is intended to enable risk-informed prioritization of safety- and reliability-focused research and development. A central Argonne task during this project was a reliability assessment of passive safety systems, which included the Reactor Vessel Auxiliary Cooling System (RVACS) and the inherent reactivity feedbacks of the metal fuel core. Both systems were examined utilizing a methodology derived from the Reliability Method for Passive Safety Functions (RMPS), with an emphasis on developing success criteria based on mechanistic system modeling while also maintaining consistency with the Fuel Damage Categories (FDCs) of the mechanistic source term assessment. This paper provides an overview of the reliability analyses of both systems, including highlights of the FMEAs, the construction of best-estimate models, uncertain parameter screening and propagation, and the quantification of system failure probability. In particular, special focus is given to the methodologies to perform the analysis of uncertainty propagation and the determination of the likelihood of violating FDC limits. Additionally, important lessons learned are also reviewed, such as optimal sampling methodologies for the discovery of low likelihood failure events and strategies for the combined treatment of aleatory and epistemic uncertainties.

  2. Circumvention of inherent or acquired cytotoxic drug resistance in vitro using combinations of modulating agents.

    Science.gov (United States)

    Cadagan, David; Merry, Stephen

    2013-10-01

    Modulating agents are used to circumvent drug resistance in the clinical setting. However achievable serum concentrations are often lower than those which are optimal in vitro. Combination of modulating agents with non-overlapping toxicities may overcome this obstacle. We have investigated combinations of three modulating agents (quinine, verapamil, and cinnarizine) to circumvent inherent or acquired resistance to the cytotoxic drugs doxorubicin, vincristine and paclitaxel. Dose-response curves to cytotoxic drugs in the presence/absence of modulating agents were determined using colony formation and cell proliferation assays. Doxorubicin accumulation into cell monolayers was measured by fluorescence spectrophotometry. Greater (1.9-fold) sensitisation to particular cytotoxic drugs was observed for certain combinations of modulating agents compared to individual effects. The most effective combination was quinine-plus-verapamil with the cytotoxic drug doxorubicin. This increase in sensitivity was associated with increased doxorubicin accumulation. Such enhanced activity was, however, not observed for all combinations of modulating agents or for all studied cytotoxic drugs. The findings of the present study suggest certain combinations of modulating agents to have a clinical role in circumventing drug resistance. Particular combinations of modulating agents must be carefully chosen to suit particular cytotoxic drug treatments.

  3. Bionic Ears: Their Development and Future Advances Using Neurotrophins and Inherently Conducting Polymers

    Directory of Open Access Journals (Sweden)

    Graeme M. Clark

    2004-01-01

    Full Text Available The development of the multiple-channel bionic ear for hearing and speech understanding in profoundly deaf people is the result of integrating biological and physical sciences with engineering. It is the first clinically successful restoration of sensory and brain function, and brings electronic technology into a direct functional relationship with human consciousness. It presently transmits essential place and coarse temporal information for the coding of frequency, but the fine temporal and place excitation of groups of nerve fibres is inadequate for high-fidelity sound. This is required for adequate musical appreciation and hearing in noise. Research has demonstrated that nerve growth factors preserve the peripheral processes of the auditory nerves so that an electrode array placed close to these fibres could produce this fine temporal and spatial coding. The nerve growth factors can be incorporated into inherently conducting polymers that are part of the array so the peripheral processes can be preserved at the same time as they are electrically stimulated.

  4. Retrieving Marine Inherent Optical Properties from Satellites Using Temperature and Salinity-dependent Backscattering by Seawater

    Science.gov (United States)

    Werdell, Paul J.; Franz, Bryan Alden; Lefler, Jason Travis; Robinson, Wayne D.; Boss, Emmanuel

    2013-01-01

    Time-series of marine inherent optical properties (IOPs) from ocean color satellite instruments provide valuable data records for studying long-term time changes in ocean ecosystems. Semi-analytical algorithms (SAAs) provide a common method for estimating IOPs from radiometric measurements of the marine light field. Most SAAs assign constant spectral values for seawater absorption and backscattering, assume spectral shape functions of the remaining constituent absorption and scattering components (e.g., phytoplankton, non-algal particles, and colored dissolved organic matter), and retrieve the magnitudes of each remaining constituent required to match the spectral distribution of measured radiances. Here, we explore the use of temperature- and salinity-dependent values for seawater backscattering in lieu of the constant spectrum currently employed by most SAAs. Our results suggest that use of temperature- and salinity-dependent seawater spectra elevate the SAA-derived particle backscattering, reduce the non-algal particles plus colored dissolved organic matter absorption, and leave the derived absorption by phytoplankton unchanged.

  5. An analytic framework for developing inherently-manufacturable pop-up laminate devices

    International Nuclear Information System (INIS)

    Aukes, Daniel M; Goldberg, Benjamin; Wood, Robert J; Cutkosky, Mark R

    2014-01-01

    Spurred by advances in manufacturing technologies developed around layered manufacturing technologies such as PC-MEMS, SCM, and printable robotics, we propose a new analytic framework for capturing the geometry of folded composite laminate devices and the mechanical processes used to manufacture them. These processes can be represented by combining a small set of geometric operations which are general enough to encompass many different manufacturing paradigms. Furthermore, such a formulation permits one to construct a variety of geometric tools which can be used to analyze common manufacturability concepts, such as tool access, part removability, and device support. In order to increase the speed of development, reduce the occurrence of manufacturing problems inherent with current design methods, and reduce the level of expertise required to develop new devices, the framework has been implemented in a new design tool called popupCAD, which is suited for the design and development of complex folded laminate devices. We conclude with a demonstration of utility of the tools by creating a folded leg mechanism. (paper)

  6. Generalized Ocean Color Inversion Model for Retrieving Marine Inherent Optical Properties

    Science.gov (United States)

    Werdell, P. Jeremy; Franz, Bryan A.; Bailey, Sean W.; Feldman, Gene C.; Boss, Emmanuel; Brando, Vittorio E.; Dowell, Mark; Hirata, Takafumi; Lavender, Samantha J.; Lee, ZhongPing; hide

    2013-01-01

    Ocean color measured from satellites provides daily, global estimates of marine inherent optical properties (IOPs). Semi-analytical algorithms (SAAs) provide one mechanism for inverting the color of the water observed by the satellite into IOPs. While numerous SAAs exist, most are similarly constructed and few are appropriately parameterized for all water masses for all seasons. To initiate community-wide discussion of these limitations, NASA organized two workshops that deconstructed SAAs to identify similarities and uniqueness and to progress toward consensus on a unified SAA. This effort resulted in the development of the generalized IOP (GIOP) model software that allows for the construction of different SAAs at runtime by selection from an assortment of model parameterizations. As such, GIOP permits isolation and evaluation of specific modeling assumptions, construction of SAAs, development of regionally tuned SAAs, and execution of ensemble inversion modeling. Working groups associated with the workshops proposed a preliminary default configuration for GIOP (GIOP-DC), with alternative model parameterizations and features defined for subsequent evaluation. In this paper, we: (1) describe the theoretical basis of GIOP; (2) present GIOP-DC and verify its comparable performance to other popular SAAs using both in situ and synthetic data sets; and, (3) quantify the sensitivities of their output to their parameterization. We use the latter to develop a hierarchical sensitivity of SAAs to various model parameterizations, to identify components of SAAs that merit focus in future research, and to provide material for discussion on algorithm uncertainties and future ensemble applications.

  7. Chronic kidney disease: an inherent risk factor for acute kidney injury?

    Science.gov (United States)

    Singh, Prabhleen; Rifkin, Dena E; Blantz, Roland C

    2010-09-01

    Epidemiologic evidence suggests that chronic kidney disease (CKD) is a risk factor for acute kidney injury (AKI) due to the prevalence of CKD in patients who have episodes of AKI. However, the high burden of comorbidities such as age, diabetes, peripheral vascular, cardiovascular, and liver disease accompanying CKD, and the difficulties of defining AKI in the setting of CKD make these observations difficult to interpret. These comorbidities not only could alter the course of AKI but also may be the driving force behind the epidemiologic association between CKD and AKI because of systemic changes and/or increased exposure to potential nephrotoxic risks. Here, we contend that studies suggesting that CKD is a risk factor for AKI may suffer from residual confounding and reflect an overall susceptibility to illness rather than biologic susceptibility of the kidney parenchyma to injury. In support of our argument, we discuss the clinical evidence from epidemiologic studies, and the knowledge obtained from animal models on the pathophysiology of AKI and CKD, demonstrating a preconditioning influence of the previously impaired kidneys against subsequent injury. We conclude that, under careful analysis, factors apart from the inherent pathophysiology of the diseased kidney may be responsible for the increased frequency of AKI in CKD patients, and the impact of CKD on the risk and severity of AKI needs further investigation. Moreover, certain elements in the pathophysiology of a previously injured kidney may, surprisingly, bear out to be protective against AKI.

  8. Preliminary risk assessment of the Integral Inherently-Safe Light Water Reactor

    International Nuclear Information System (INIS)

    McCarroll, Kellen R.; Lee, John C.; Manera, Annalisa; Memmott, Matthew J.; Ferroni, Paolo

    2017-01-01

    The Integral, Inherently Safe Light Water Reactor (I 2 S-LWR) concept seeks to significantly increase nuclear power plant safety. The project implements a safety-by-design philosophy, eliminating several initiating events and providing novel, passive safety systems at the conceptual phase. Pursuit of unparalleled safety employs an integrated development process linking design with deterministic and probabilistic safety analyses. Unique aspects of the I 2 S-LWR concept and design process present challenges to the probabilistic risk assessment (PRA), particularly regarding overall flexibility, auditability and resolution of results. Useful approaches to initiating events and conditional failures are presented. To exemplify the risk-informed design process using PRA, a trade-off study of two safety system configurations is presented. Although further optimization is required, preliminary results indicate that the I 2 S-LWR can achieve a core damage frequency (CDF) from internal events less than 1.01 × 10 −8 /ry, including reactor vessel ruptures. Containment bypass frequency due to primary heat exchanger rupture is found to be comparable to non-vessel rupture CDF.

  9. Inherent Tumor Characteristics That Limit Effective and Safe Resection of Giant Nonfunctioning Pituitary Adenomas.

    Science.gov (United States)

    Nishioka, Hiroshi; Hara, Takayuki; Nagata, Yuichi; Fukuhara, Noriaki; Yamaguchi-Okada, Mitsuo; Yamada, Shozo

    2017-10-01

    Surgical treatment of giant pituitary adenomas is sometimes challenging. We present our surgical series of giant nonfunctioning adenomas to shed light on the limitations of effective and safe tumor resection. The preoperative tumor characteristics, surgical approaches, outcome, and histology of giant nonfunctioning adenoma (>40 mm) in 128 consecutive surgical patients are reviewed. The follow-up period ranged from 19 to 113 months (mean 62.2 months). A transsphenoidal approach was used in the treatment of 109 patients and a combined transsphenoidal transcranial approach in 19 patients. A total of 93 patients (72.7%) underwent total resection or subtotal resection apart from the cavernous sinus (CS). The degree of tumor resection, excluding the marked CS invasion, was lower in tumors that were larger (P = 0.0107), showed massive intracranial extension (P = 0.0352), and had an irregular configuration (P = 0.0016). Permanent surgical complications developed in 28 patients (22.0%). Long-term tumor control was achieved in all patients by single surgery, including 43 patients with adjuvant radiotherapy. Most tumors were histologically benign, with a low MIB-1 index (inherent factors that independently limit effective resection. These high-risk tumors require an individualized therapeutic strategy. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Late-onset Alzheimer's disease is associated with inherent changes in bioenergetics profiles.

    Science.gov (United States)

    Sonntag, Kai-C; Ryu, Woo-In; Amirault, Kristopher M; Healy, Ryan A; Siegel, Arthur J; McPhie, Donna L; Forester, Brent; Cohen, Bruce M

    2017-10-25

    Body-wide changes in bioenergetics, i.e., energy metabolism, occur in normal aging and disturbed bioenergetics may be an important contributing mechanism underlying late-onset Alzheimer's disease (LOAD). We investigated the bioenergetic profiles of fibroblasts from LOAD patients and healthy controls, as a function of age and disease. LOAD cells exhibited an impaired mitochondrial metabolic potential and an abnormal redox potential, associated with reduced nicotinamide adenine dinucleotide metabolism and altered citric acid cycle activity, but not with disease-specific changes in mitochondrial mass, production of reactive oxygen species, transmembrane instability, or DNA deletions. LOAD fibroblasts demonstrated a shift in energy production to glycolysis, despite an inability to increase glucose uptake in response to IGF-1. The increase of glycolysis and the abnormal mitochondrial metabolic potential in LOAD appeared to be inherent, as they were disease- and not age-specific. Our findings support the hypothesis that impairment in multiple interacting components of bioenergetic metabolism may be a key mechanism contributing to the risk and pathophysiology of LOAD.

  11. Widespread protein aggregation as an inherent part of aging in C. elegans.

    Directory of Open Access Journals (Sweden)

    Della C David

    Full Text Available Aberrant protein aggregation is a hallmark of many age-related diseases, yet little is known about whether proteins aggregate with age in a non-disease setting. Using a systematic proteomics approach, we identified several hundred proteins that become more insoluble with age in the multicellular organism Caenorhabditis elegans. These proteins are predicted to be significantly enriched in beta-sheets, which promote disease protein aggregation. Strikingly, these insoluble proteins are highly over-represented in aggregates found in human neurodegeneration. We examined several of these proteins in vivo and confirmed their propensity to aggregate with age. Different proteins aggregated in different tissues and cellular compartments. Protein insolubility and aggregation were significantly delayed or even halted by reduced insulin/IGF-1-signaling, which also slows aging. We found a significant overlap between proteins that become insoluble and proteins that influence lifespan and/or polyglutamine-repeat aggregation. Moreover, overexpressing one aggregating protein enhanced polyglutamine-repeat pathology. Together our findings indicate that widespread protein insolubility and aggregation is an inherent part of aging and that it may influence both lifespan and neurodegenerative disease.

  12. Visual analytics of inherently noisy crowdsourced data on ultra high resolution displays

    Science.gov (United States)

    Huynh, Andrew; Ponto, Kevin; Lin, Albert Yu-Min; Kuester, Falko

    The increasing prevalence of distributed human microtasking, crowdsourcing, has followed the exponential increase in data collection capabilities. The large scale and distributed nature of these microtasks produce overwhelming amounts of information that is inherently noisy due to the nature of human input. Furthermore, these inputs create a constantly changing dataset with additional information added on a daily basis. Methods to quickly visualize, filter, and understand this information over temporal and geospatial constraints is key to the success of crowdsourcing. This paper present novel methods to visually analyze geospatial data collected through crowdsourcing on top of remote sensing satellite imagery. An ultra high resolution tiled display system is used to explore the relationship between human and satellite remote sensing data at scale. A case study is provided that evaluates the presented technique in the context of an archaeological field expedition. A team in the field communicated in real-time with and was guided by researchers in the remote visual analytics laboratory, swiftly sifting through incoming crowdsourced data to identify target locations that were identified as viable archaeological sites.

  13. Improvement of inherent safety features in CSR (Coupled Spectrum Reactor) for treating MA

    International Nuclear Information System (INIS)

    Aziz, F.; Kitamoto, Asashi.

    1996-01-01

    Burning and/or transmutation (B/T) of MA is proposed here using a CSR (Coupled Spectrum Reactor) concept. CSR was based on a modified conventional 1150 MWe-PWR system, and consisted of two core regions for thermal and fast neutrons, respectively. The B/T fuel used was supposed such that MA discharged from 1 GWe-LWR were mixed homogeneously in LWR fuel. The geometry of B/T fuel in the outer region was left the same with that of PWR, while in the inner region the B/T fuel was arranged in a tight-lattice geometry that allowed a higher fuel to coolant volume ratio, (V m /V f ). In order to improve its inherent safety features, several cases of CSR were studied and compared, each case used different fuel type in the inner region. The result of the calculations showed that safety features can be improved by using composite fuel of ( 235 U-Pu- 238 U) in the inner region. The equilibrium of main isotopes in CSR can be achieved after about 5 recycle stages. This study also showed that the CSR can burn and transmute MA up to 808 kg/stage in a single reactor operated with a reactivity swing of 2.8 % Δk/kk'. (author)

  14. Latent HIV reservoirs exhibit inherent resistance to elimination by CD8+ T cells.

    Science.gov (United States)

    Huang, Szu-Han; Ren, Yanqin; Thomas, Allison S; Chan, Dora; Mueller, Stefanie; Ward, Adam R; Patel, Shabnum; Bollard, Catherine M; Cruz, Conrad Russell; Karandish, Sara; Truong, Ronald; Macedo, Amanda B; Bosque, Alberto; Kovacs, Colin; Benko, Erika; Piechocka-Trocha, Alicja; Wong, Hing; Jeng, Emily; Nixon, Douglas F; Ho, Ya-Chi; Siliciano, Robert F; Walker, Bruce D; Jones, R Brad

    2018-02-01

    The presence of persistent, latent HIV reservoirs in CD4+ T cells obstructs current efforts to cure infection. The so-called kick-and-kill paradigm proposes to purge these reservoirs by combining latency-reversing agents with immune effectors such as cytotoxic T lymphocytes. Support for this approach is largely based on success in latency models, which do not fully reflect the makeup of latent reservoirs in individuals on long-term antiretroviral therapy (ART). Recent studies have shown that CD8+ T cells have the potential to recognize defective proviruses, which comprise the vast majority of all infected cells, and that the proviral landscape can be shaped over time due to in vivo clonal expansion of infected CD4+ T cells. Here, we have shown that treating CD4+ T cells from ART-treated individuals with combinations of potent latency-reversing agents and autologous CD8+ T cells consistently reduced cell-associated HIV DNA, but failed to deplete replication-competent virus. These CD8+ T cells recognized and potently eliminated CD4+ T cells that were newly infected with autologous reservoir virus, ruling out a role for both immune escape and CD8+ T cell dysfunction. Thus, our results suggest that cells harboring replication-competent HIV possess an inherent resistance to CD8+ T cells that may need to be addressed to cure infection.

  15. Readjusting one's life in the tension inherent in work and motherhood.

    Science.gov (United States)

    Alstveit, Marit; Severinsson, Elisabeth; Karlsen, Bjørg

    2011-10-01

    This paper is a report on a study undertaken to interpret employed first-time mothers' experiences of returning to work after maternity leave, in a Norwegian context. Despite the increasing rate of employed fertile women and increasing welfare benefits to support the work-life balance, the first years after giving birth are described as being the most demanding on mothers' health. However, little is known about mothers' experiences of returning to work after maternity leave. The study included nine Norwegian employees who were individually interviewed during the first months after their return to work following maternity leave. The interviews were conducted during 2009 and interpreted using a method grounded in hermeneutics. Overall, the meaning of returning to work was interpreted as 'Readjusting one's life in the tension inherent in work and motherhood'. This comprehensive theme was based on three sub-themes: (a) Striving to manage the workload and taking responsibility for the best interests of the child, (b) Struggling with feelings of not being a good enough mother, and (c) Maintaining a balance between sensitivity and self-confidence. Returning to work after maternity leave appears to be a transitional phase that can be critical to the well-being of first-time mothers. To support women during this phase, employers and public health nurses should monitor the work in relation to the women's capacity and value their competence both as employees and mothers. © 2011 The Authors. Journal of Advanced Nursing © 2011 Blackwell Publishing Ltd.

  16. Underwater Inherent Optical Properties Estimation Using a Depth Aided Deep Neural Network.

    Science.gov (United States)

    Yu, Zhibin; Wang, Yubo; Zheng, Bing; Zheng, Haiyong; Wang, Nan; Gu, Zhaorui

    2017-01-01

    Underwater inherent optical properties (IOPs) are the fundamental clues to many research fields such as marine optics, marine biology, and underwater vision. Currently, beam transmissometers and optical sensors are considered as the ideal IOPs measuring methods. But these methods are inflexible and expensive to be deployed. To overcome this problem, we aim to develop a novel measuring method using only a single underwater image with the help of deep artificial neural network. The power of artificial neural network has been proved in image processing and computer vision fields with deep learning technology. However, image-based IOPs estimation is a quite different and challenging task. Unlike the traditional applications such as image classification or localization, IOP estimation looks at the transparency of the water between the camera and the target objects to estimate multiple optical properties simultaneously. In this paper, we propose a novel Depth Aided (DA) deep neural network structure for IOPs estimation based on a single RGB image that is even noisy. The imaging depth information is considered as an aided input to help our model make better decision.

  17. Uncovering inherent cellular plasticity of multiciliated ependyma leading to ventricular wall transformation and hydrocephalus.

    Science.gov (United States)

    Abdi, Khadar; Lai, Chun-Hsiang; Paez-Gonzalez, Patricia; Lay, Mark; Pyun, Joon; Kuo, Chay T

    2018-04-25

    Specialized, differentiated cells often perform unique tasks that require them to maintain a stable phenotype. Multiciliated ependymal cells (ECs) are unique glial cells lining the brain ventricles, important for cerebral spinal fluid circulation. While functional ECs are needed to prevent hydrocephalus, they have also been reported to generate new neurons: whether ECs represent a stable cellular population remains unclear. Via a chemical screen we found that mature ECs are inherently plastic, with their multiciliated state needing constant maintenance by the Foxj1 transcription factor, which paradoxically is rapidly turned over by the ubiquitin-proteasome system leading to cellular de-differentiation. Mechanistic analyses revealed a novel NF-κB-independent IKK2 activity stabilizing Foxj1 in mature ECs, and we found that known IKK2 inhibitors including viruses and growth factors robustly induced Foxj1 degradation, EC de-differentiation, and hydrocephalus. Although mature ECs upon de-differentiation can divide and regenerate multiciliated ECs, we did not detect evidence supporting EC's neurogenic potential.

  18. The Development and Evaluation of Inherent RPCS for the APR1400

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jae D.; Ryu, Seok H.; Jung, Dong C.; Kim, Joon S.; Baek, Byung C.; Sung, Song K.; You, Guk J. [KNF, Daejeon (Korea, Republic of); Kim, Han G. [KHNP, Daejeon (Korea, Republic of); Chi, Sung G. [KOPEC, Daejeon (Korea, Republic of)

    2008-10-15

    The APR1400 RPCS (Reactor Power Cutback System) is designed to rapidly reduce the core power to eliminate the need for a reactor trip following a large load rejection or a loss of two main feedwater pumps at high power. GDC (General Design Criteria) 25 says 'Protection system requirements for reactivity control malfunctions. The protection system shall be designed to assure that SAFDL (Specified Acceptable Fuel Design Limits) are not exceeded for any single malfunction of the reactivity control systems, such as accidental withdrawal (not ejection or dropout) of control rods.' In order to comply GDC 25, CPCS (Core Protection Calculator System) will apply a big power penalty({approx} 1.3) to determine the minimum DNBR (Departure from Nucleate Boiling Ratio), the maximum LPD(Local Power Density) and reactor may immediately trip by CPCS low DNBR and high LPD during high power operation for 12-finger CEA drop. The purpose of this study is to develop the inherent RPCS to avoid unwanted reactor trips due to a 12-finger CEA drop. In order to accomplish this purpose, the CPCS should be modified to send RPCS actuation signal and not to apply power penalty due to 12-finger CEA drop for a shot period. During this period which is determined by assessment of safety, the SAFDL will not be violated without any CPCS trip function. The system and CPCS performance is evaluated to verify that CPCS trip does not occurred during 12-finger CEA drop event.

  19. Stable Regulation of Cell Cycle Events in Mycobacteria: Insights From Inherently Heterogeneous Bacterial Populations.

    Science.gov (United States)

    Logsdon, Michelle M; Aldridge, Bree B

    2018-01-01

    Model bacteria, such as E. coli and B. subtilis , tightly regulate cell cycle progression to achieve consistent cell size distributions and replication dynamics. Many of the hallmark features of these model bacteria, including lateral cell wall elongation and symmetric growth and division, do not occur in mycobacteria. Instead, mycobacterial growth is characterized by asymmetric polar growth and division. This innate asymmetry creates unequal birth sizes and growth rates for daughter cells with each division, generating a phenotypically heterogeneous population. Although the asymmetric growth patterns of mycobacteria lead to a larger variation in birth size than typically seen in model bacterial populations, the cell size distribution is stable over time. Here, we review the cellular mechanisms of growth, division, and cell cycle progression in mycobacteria in the face of asymmetry and inherent heterogeneity. These processes coalesce to control cell size. Although Mycobacterium smegmatis and Mycobacterium bovis Bacillus Calmette-Guérin (BCG) utilize a novel model of cell size control, they are similar to previously studied bacteria in that initiation of DNA replication is a key checkpoint for cell division. We compare the regulation of DNA replication initiation and strategies used for cell size homeostasis in mycobacteria and model bacteria. Finally, we review the importance of cellular organization and chromosome segregation relating to the physiology of mycobacteria and consider how new frameworks could be applied across the wide spectrum of bacterial diversity.

  20. Stable Regulation of Cell Cycle Events in Mycobacteria: Insights From Inherently Heterogeneous Bacterial Populations

    Directory of Open Access Journals (Sweden)

    Michelle M. Logsdon

    2018-03-01

    Full Text Available Model bacteria, such as E. coli and B. subtilis, tightly regulate cell cycle progression to achieve consistent cell size distributions and replication dynamics. Many of the hallmark features of these model bacteria, including lateral cell wall elongation and symmetric growth and division, do not occur in mycobacteria. Instead, mycobacterial growth is characterized by asymmetric polar growth and division. This innate asymmetry creates unequal birth sizes and growth rates for daughter cells with each division, generating a phenotypically heterogeneous population. Although the asymmetric growth patterns of mycobacteria lead to a larger variation in birth size than typically seen in model bacterial populations, the cell size distribution is stable over time. Here, we review the cellular mechanisms of growth, division, and cell cycle progression in mycobacteria in the face of asymmetry and inherent heterogeneity. These processes coalesce to control cell size. Although Mycobacterium smegmatis and Mycobacterium bovis Bacillus Calmette-Guérin (BCG utilize a novel model of cell size control, they are similar to previously studied bacteria in that initiation of DNA replication is a key checkpoint for cell division. We compare the regulation of DNA replication initiation and strategies used for cell size homeostasis in mycobacteria and model bacteria. Finally, we review the importance of cellular organization and chromosome segregation relating to the physiology of mycobacteria and consider how new frameworks could be applied across the wide spectrum of bacterial diversity.

  1. Architecture and inherent robustness of a bacterial cell-cycle control system.

    Science.gov (United States)

    Shen, Xiling; Collier, Justine; Dill, David; Shapiro, Lucy; Horowitz, Mark; McAdams, Harley H

    2008-08-12

    A closed-loop control system drives progression of the coupled stalked and swarmer cell cycles of the bacterium Caulobacter crescentus in a near-mechanical step-like fashion. The cell-cycle control has a cyclical genetic circuit composed of four regulatory proteins with tight coupling to processive chromosome replication and cell division subsystems. We report a hybrid simulation of the coupled cell-cycle control system, including asymmetric cell division and responses to external starvation signals, that replicates mRNA and protein concentration patterns and is consistent with observed mutant phenotypes. An asynchronous sequential digital circuit model equivalent to the validated simulation model was created. Formal model-checking analysis of the digital circuit showed that the cell-cycle control is robust to intrinsic stochastic variations in reaction rates and nutrient supply, and that it reliably stops and restarts to accommodate nutrient starvation. Model checking also showed that mechanisms involving methylation-state changes in regulatory promoter regions during DNA replication increase the robustness of the cell-cycle control. The hybrid cell-cycle simulation implementation is inherently extensible and provides a promising approach for development of whole-cell behavioral models that can replicate the observed functionality of the cell and its responses to changing environmental conditions.

  2. Computability, Gödel's incompleteness theorem, and an inherent limit on the predictability of evolution.

    Science.gov (United States)

    Day, Troy

    2012-04-07

    The process of evolutionary diversification unfolds in a vast genotypic space of potential outcomes. During the past century, there have been remarkable advances in the development of theory for this diversification, and the theory's success rests, in part, on the scope of its applicability. A great deal of this theory focuses on a relatively small subset of the space of potential genotypes, chosen largely based on historical or contemporary patterns, and then predicts the evolutionary dynamics within this pre-defined set. To what extent can such an approach be pushed to a broader perspective that accounts for the potential open-endedness of evolutionary diversification? There have been a number of significant theoretical developments along these lines but the question of how far such theory can be pushed has not been addressed. Here a theorem is proven demonstrating that, because of the digital nature of inheritance, there are inherent limits on the kinds of questions that can be answered using such an approach. In particular, even in extremely simple evolutionary systems, a complete theory accounting for the potential open-endedness of evolution is unattainable unless evolution is progressive. The theorem is closely related to Gödel's incompleteness theorem, and to the halting problem from computability theory.

  3. Key issues

    International Nuclear Information System (INIS)

    Cook, N.G.W.

    1980-01-01

    Successful modeling of the thermo-mechanical and hydrochemical behavior of radioactive waste repositories in hard rock is possible in principle. Because such predictions lie outside the realm of experience, their adequacy depends entirely upon a thorough understanding of three fundamental questions: an understanding of the chemical and physical processess that determine the behavior of rock and all its complexities; accurate and realistic numerical models of the geologic media within which a repository may be built; and sufficient in-situ data covering the entire geologic region affected by, or effecting the behavior of a repository. At present sufficient is known to be able to identify most of those areas which require further attention. These areas extend all the way from a complete understanding of the chemical and physical processes determining the behavior of rock through to the exploration mapping and testing that must be done during the development of any potential repository. Many of the techniques, laboratory equipment, field instrumentation, and numerical methods needed to accomplish this do not exist at present. Therefore it is necessary to accept that a major investment in scientific research is required to generate this information over the next few years. The spectrum of scientific and engineering activities is wide extending from laboratory measurements through the development of numerical models to the measurement of data in-situ, but there is every prospect that sufficient can be done to resolve these key issues. However, to do so requires overt recognition of the many gaps which exist in our knowledge and abilities today, and of the need to bridge these gaps and of the significant costs involved in doing so

  4. Predicting welding distortion in a panel structure with longitudinal stiffeners using inherent deformations obtained by inverse analysis method.

    Science.gov (United States)

    Liang, Wei; Murakawa, Hidekazu

    2014-01-01

    Welding-induced deformation not only negatively affects dimension accuracy but also degrades the performance of product. If welding deformation can be accurately predicted beforehand, the predictions will be helpful for finding effective methods to improve manufacturing accuracy. Till now, there are two kinds of finite element method (FEM) which can be used to simulate welding deformation. One is the thermal elastic plastic FEM and the other is elastic FEM based on inherent strain theory. The former only can be used to calculate welding deformation for small or medium scale welded structures due to the limitation of computing speed. On the other hand, the latter is an effective method to estimate the total welding distortion for large and complex welded structures even though it neglects the detailed welding process. When the elastic FEM is used to calculate the welding-induced deformation for a large structure, the inherent deformations in each typical joint should be obtained beforehand. In this paper, a new method based on inverse analysis was proposed to obtain the inherent deformations for weld joints. Through introducing the inherent deformations obtained by the proposed method into the elastic FEM based on inherent strain theory, we predicted the welding deformation of a panel structure with two longitudinal stiffeners. In addition, experiments were carried out to verify the simulation results.

  5. Factors contributing to inherent varus alignment of lower limb in normal Asian adults: role of tibial plateau inclination.

    Science.gov (United States)

    Shetty, Gautam M; Mullaji, Arun; Bhayde, Sagar; Nha, Kyung Wook; Oh, Hyoung Keun

    2014-03-01

    This prospective study aimed to evaluate radiographically, mechanical or hip-knee-ankle (HKA) axis in healthy, asymptomatic, Asian (Indian and Korean) adults between 20 and 40 years of age to determine the incidence of inherent varus (mechanical limb alignment of >3° varus) and the factors influencing it. Three hundred and eighty-eight lower limbs were evaluated using full length, standing hip-to-ankle radiographs in 198 healthy, asymptomatic, Asian (Indian and Korean) adults between 20 and 40 years of age to assess the hip-knee-ankle (HKA) angle, medial proximal tibial angle (MPTA), femoral bowing and femoral neck-shaft angle to determine the incidence of inherent varus (mechanical limb alignment of >3° varus) and the factors influencing it. Overall, the mean HKA angle was 177.6°±2.6° with 34.5% of limbs in inherent varus (mean HKA angle 174.9°±1.8°). The incidence of inherent varus was significantly higher (p=0.01) in males (40%) compared to females (28%) but similar among Indian (34%) and Korean subjects (35%). The hip-knee-ankle (HKA) angle showed significant positive correlation (r=0.82, palignment of the lower limb is fairly common among asymptomatic, Asian adults. These results raise several pertinent questions regarding the role of inherent varus in the aetiopathogenesis of knee osteoarthritis and in lower limb realignment procedures. © 2013 Elsevier B.V. All rights reserved.

  6. Identification and characterization of passive safety system and inherent safety feature building blocks for advanced light-water reactors

    International Nuclear Information System (INIS)

    Forsberg, C.W.

    1989-01-01

    Oak Ridge National Laboratory (ORNL) is investigating passive and inherent safety options for Advanced Light-Water Reactors (ALWRs). A major activity in 1989 includes identification and characterization of passive safety system and inherent safety feature building blocks, both existing and proposed, for ALWRs. Preliminary results of this work are reported herein. This activity is part of a larger effort by the US Department of Energy, reactor vendors, utilities, and others in the United States to develop improved LWRs. The Advanced Boiling Water Reactor (ABWR) program and the Advanced Pressurized Water Reactor (APWR) program have as goals improved, commercially available LWRs in the early 1990s. The Advanced Simplified Boiling Water Reactor (ASBWR) program and the AP-600 program are developing more advanced reactors with increased use of passive safety systems. It is planned that these reactors will become commercially available in the mid 1990s. The ORNL program is an exploratory research program for LWRs beyond the year 2000. Desired long-term goals for such reactors include: (1) use of only passive and inherent safety, (2) foolproof against operator errors, (3) malevolence resistance against internal sabotage and external assault and (4) walkaway safety. The acronym ''PRIME'' [Passive safety, Resilient operation, Inherent safety, Malevolence resistance, and Extended (walkaway) safety] is used to summarize these desired characteristics. Existing passive and inherent safety options are discussed in this document

  7. Improving Coastal Ocean Color Validation Capabilities through Application of Inherent Optical Properties (IOPs)

    Science.gov (United States)

    Mannino, Antonio

    2008-01-01

    Understanding how the different components of seawater alter the path of incident sunlight through scattering and absorption is essential to using remotely sensed ocean color observations effectively. This is particularly apropos in coastal waters where the different optically significant components (phytoplankton, detrital material, inorganic minerals, etc.) vary widely in concentration, often independently from one another. Inherent Optical Properties (IOPs) form the link between these biogeochemical constituents and the Apparent Optical Properties (AOPs). understanding this interrelationship is at the heart of successfully carrying out inversions of satellite-measured radiance to biogeochemical properties. While sufficient covariation of seawater constituents in case I waters typically allows empirical algorithms connecting AOPs and biogeochemical parameters to behave well, these empirical algorithms normally do not hold for case I1 regimes (Carder et al. 2003). Validation in the context of ocean color remote sensing refers to in-situ measurements used to verify or characterize algorithm products or any assumption used as input to an algorithm. In this project, validation capabilities are considered those measurement capabilities, techniques, methods, models, etc. that allow effective validation. Enhancing current validation capabilities by incorporating state-of-the-art IOP measurements and optical models is the purpose of this work. Involved in this pursuit is improving core IOP measurement capabilities (spectral, angular, spatio-temporal resolutions), improving our understanding of the behavior of analytical AOP-IOP approximations in complex coastal waters, and improving the spatial and temporal resolution of biogeochemical data for validation by applying biogeochemical-IOP inversion models so that these parameters can be computed from real-time IOP sensors with high sampling rates. Research cruises supported by this project provides for collection and

  8. The in vitro digestibility of beef varies with its inherent ultimate pH.

    Science.gov (United States)

    Farouk, Mustafa M; Wu, Guojie; Frost, Deborah A; Clerens, Stefan; Knowles, Scott O

    2014-11-01

    Animal carcasses and cuts of meat are usually differentiated and valued according to size and compositional attributes. An underappreciated variable of red meat is its inherent ultimate pH (pHu) value, which affects organoleptic and processing characteristics. This study tests the hypothesis that high pHu aged meat would be more digestible than low pHu unaged (fresh) meat. Longissimus dorsi muscles collected from 59 bull carcasses had pHu values of 5.6-6.9. These were aged for 21 days at -1.5 °C, then raw and cooked (72 °C) samples were enzymatically digested at 37 °C with pepsin (pH 1.9 for 90 min) followed by pancreatin (pH 8.0 for an additional 120 min) to simulate conditions in the stomach and small intestine, respectively. Meat proteins and peptides in the digests were separated by 1D SDS PAGE. Regardless of pHu, ageing or cooking, most sarcoplasmic and myofibrillar proteins were rapidly digested by pepsin, with concomitant release of products identified by LC-MS/MS as mainly myosin-1, -2 and -7, α-actinin-2 or -3 and tropomyosin beta and alpha chains. These products were resistant to further digestion for the entire 210 min duration of the incubation. In terms of rate and extent of digestibility of these resistant products, high pHu > low pHu (P unaged (P meat samples increased with increasing pHu (P meat was highly digestible but could be further differentiated on the basis of its pHu and the ease of digestibility of proteins. Specific carcasses or cuts could be targeted to consumer groups in order to provide benefits and add value.

  9. An optimized power conversion system concept of the integral, inherently-safe light water reactor

    International Nuclear Information System (INIS)

    Memmott, Matthew J.; Wilding, Paul R.; Petrovic, Bojan

    2017-01-01

    Highlights: • Three power conversion systems (PCS) for the I"2S-LWR are presented. • An optimization analyses was performed to evaluate these PCS alternatives. • The ideal PCS consists of 5 turbines, and obtains an overall efficiency of 35.7%. - Abstract: The integral, inherently safe light water reactor (I"2S-LWR) has been developed to significantly enhance passive safety capabilities while maintaining cost competitiveness relative to the current light water reactor (LWR) fleet. The compact heat exchangers of the I"2S-LWR preclude boiling of the secondary fluid, which decreases the probability of heat exchanger failure, but this requires the addition of a flash drum, which negatively affects the overall plant thermodynamic efficiency. A state of the art Rankine cycle is proposed for the I"2S-LWR to increase the thermodynamic efficiency by utilizing a flash drum with optimized operational parameters. In presenting this option for power conversion in the I"2S-LWR power plant, the key metric used in rating the performance is the overall net thermodynamic efficiency of the cycle. In evaluating the flash-Rankine cycle, three basic industrial concepts are evaluated, one without an intermediate pressure turbine, one with an intermediate turbine and one reheat stream, and one with an intermediate turbine and two reheat streams. For each configuration, a single-path multi-variable optimization is undertaken to maximize the thermal efficiency. The third configuration with an intermediate turbine and 2 reheat streams is the most effective concept, with an optimized efficiency of 35.7%.

  10. Impact of calcification state on the inherent optical properties of Emiliania huxleyi coccoliths and coccolithophores

    Science.gov (United States)

    Bi, Lei; Yang, Ping

    2015-04-01

    Understanding the inherent optical properties (IOPs) of coccoliths and coccolithophores is important in oceanic radiative transfer simulations and remote sensing implementations. In this study, the invariant imbedding T-matrix method (II-TM) is employed to investigate the IOPs of coccoliths and coccolithophores. The Emiliania huxleyi (Ehux) coccolith and coccolithophore models are built based on observed biometric parameters including the eccentricity, the number of slits, and the rim width of detached coccoliths. The calcification state that specifies the amount of calcium of a single coccolith is critical in the determination of the size-volume/mass relationship (note, the volume/mass of coccoltihs at different calcification states are different although the diameters are the same). The present results show that the calcification state, namely, under-calcification, normal-calcification, or over-calcification, significantly influences the backscattering cross section and the phase matrix. Furthermore, the linear depolarization ratio of the light scattered by coccoliths is sensitive to the degree of calcification, and provides a potentially valuable parameter for interpreting oceanic remote sensing data. The phase function of an ensemble of randomly oriented coccolithophores has a similar pattern to that of individual coccoliths, but the forward scattering is dominant in the coccolithophores due to the large geometric cross sections. The linear depolarization ratio associated with coccolithophores is found to be larger than that for coccoliths as polarization is more sensitive to multiple scattering than the phase function. The simulated coccolithophore phase matrix numerical results are compared with laboratory measurements. For scattering angles larger than 100°, an increase of the phase function with respect to the scattering angle is confirmed based on the present coccolithophore model while the spherical approximation fails.

  11. Impact of calcification state on the inherent optical properties of Emiliania huxleyi coccoliths and coccolithophores

    International Nuclear Information System (INIS)

    Bi, Lei; Yang, Ping

    2015-01-01

    Understanding the inherent optical properties (IOPs) of coccoliths and coccolithophores is important in oceanic radiative transfer simulations and remote sensing implementations. In this study, the invariant imbedding T-matrix method (II-TM) is employed to investigate the IOPs of coccoliths and coccolithophores. The Emiliania huxleyi (Ehux) coccolith and coccolithophore models are built based on observed biometric parameters including the eccentricity, the number of slits, and the rim width of detached coccoliths. The calcification state that specifies the amount of calcium of a single coccolith is critical in the determination of the size–volume/mass relationship (note, the volume/mass of coccoltihs at different calcification states are different although the diameters are the same). The present results show that the calcification state, namely, under-calcification, normal-calcification, or over-calcification, significantly influences the backscattering cross section and the phase matrix. Furthermore, the linear depolarization ratio of the light scattered by coccoliths is sensitive to the degree of calcification, and provides a potentially valuable parameter for interpreting oceanic remote sensing data. The phase function of an ensemble of randomly oriented coccolithophores has a similar pattern to that of individual coccoliths, but the forward scattering is dominant in the coccolithophores due to the large geometric cross sections. The linear depolarization ratio associated with coccolithophores is found to be larger than that for coccoliths as polarization is more sensitive to multiple scattering than the phase function. The simulated coccolithophore phase matrix numerical results are compared with laboratory measurements. For scattering angles larger than 100°, an increase of the phase function with respect to the scattering angle is confirmed based on the present coccolithophore model while the spherical approximation fails. - Highlights: • Realistic

  12. Gene network inherent in genomic big data improves the accuracy of prognostic prediction for cancer patients.

    Science.gov (United States)

    Kim, Yun Hak; Jeong, Dae Cheon; Pak, Kyoungjune; Goh, Tae Sik; Lee, Chi-Seung; Han, Myoung-Eun; Kim, Ji-Young; Liangwen, Liu; Kim, Chi Dae; Jang, Jeon Yeob; Cha, Wonjae; Oh, Sae-Ock

    2017-09-29

    Accurate prediction of prognosis is critical for therapeutic decisions regarding cancer patients. Many previously developed prognostic scoring systems have limitations in reflecting recent progress in the field of cancer biology such as microarray, next-generation sequencing, and signaling pathways. To develop a new prognostic scoring system for cancer patients, we used mRNA expression and clinical data in various independent breast cancer cohorts (n=1214) from the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) and Gene Expression Omnibus (GEO). A new prognostic score that reflects gene network inherent in genomic big data was calculated using Network-Regularized high-dimensional Cox-regression (Net-score). We compared its discriminatory power with those of two previously used statistical methods: stepwise variable selection via univariate Cox regression (Uni-score) and Cox regression via Elastic net (Enet-score). The Net scoring system showed better discriminatory power in prediction of disease-specific survival (DSS) than other statistical methods (p=0 in METABRIC training cohort, p=0.000331, 4.58e-06 in two METABRIC validation cohorts) when accuracy was examined by log-rank test. Notably, comparison of C-index and AUC values in receiver operating characteristic analysis at 5 years showed fewer differences between training and validation cohorts with the Net scoring system than other statistical methods, suggesting minimal overfitting. The Net-based scoring system also successfully predicted prognosis in various independent GEO cohorts with high discriminatory power. In conclusion, the Net-based scoring system showed better discriminative power than previous statistical methods in prognostic prediction for breast cancer patients. This new system will mark a new era in prognosis prediction for cancer patients.

  13. Measuring situational awareness and resolving inherent high-level fusion obstacles

    Science.gov (United States)

    Sudit, Moises; Stotz, Adam; Holender, Michael; Tagliaferri, William; Canarelli, Kathie

    2006-04-01

    Information Fusion Engine for Real-time Decision Making (INFERD) is a tool that was developed to supplement current graph matching techniques in Information Fusion models. Based on sensory data and a priori models, INFERD dynamically generates, evolves, and evaluates hypothesis on the current state of the environment. The a priori models developed are hierarchical in nature lending them to a multi-level Information Fusion process whose primary output provides a situational awareness of the environment of interest in the context of the models running. In this paper we look at INFERD's multi-level fusion approach and provide insight on the inherent problems such as fragmentation in the approach and the research being undertaken to mitigate those deficiencies. Due to the large variance of data in disparate environments, the awareness of situations in those environments can be drastically different. To accommodate this, the INFERD framework provides support for plug-and-play fusion modules which can be developed specifically for domains of interest. However, because the models running in INFERD are graph based, some default measurements can be provided and will be discussed in the paper. Among these are a Depth measurement to determine how much danger is presented by the action taking place, a Breadth measurement to gain information regarding the scale of an attack that is currently happening, and finally a Reliability measure to tell the user the credibility of a particular hypothesis. All of these results will be demonstrated in the Cyber domain where recent research has shown to be an area that is welldefined and bounded, so that new models and algorithms can be developed and evaluated.

  14. Demonstrated operational and inherent safety of the prototype fast reactor (PFR)

    International Nuclear Information System (INIS)

    Smedley, J.A.; Gregory, C.V.; Judd, A.M.

    1983-01-01

    The Prototype Fast Reactor (PFR) is sited at Dounreay, on the north coast of Scotland in the United Kingdom, and has been in operation since 1974. Three aspects of the safety of the reactor are described, including the all-important practical consideration of operational safety, a demonstration of the limited consequences of a sodium/water reaction in a steam generator and the ability of the reactor to protect itself against highly improbable incidents. Attention is drawn to the low radiation levels in the plant and the correspondingly low dose rate to personnel. A feature of PFR operation has been the stable and predictable behaviour of its core together with the high degree of reliability exhibited by the engineered safety system. No failures have occurred within the standard driver charge but two experimental fuel pins suffered cladding failure, which was detected easily by the fission gas and delayed neutron detection systems. In the steam generating units sodium and water are separated by the single steel wall of the steam tubes. Although no under-sodium leak has occurred, an experimental programme is continuing and demonstrates that were any such leak to occur its consequences would be containable and would not result in the release of sodium to the environment or any breach of the reactor containment. The final section describes the inherent safety features of the reactor which enable it to survive a range of very improbable incidents even when the engineered safeguards fail. The features considered are natural circulation, which has been demonstrated by reactor experiment; the reactor's negative power coefficient, which, for example, enables the reactor to survive a complete loss of heat sink; and the durability of the fuel pins, demonstrated by a series of boiling experiments in the Dounreay Fast Reactor (DFR). (author)

  15. Influence of the inherent properties of drinking water treatment residuals on their phosphorus adsorption capacities.

    Science.gov (United States)

    Bai, Leilei; Wang, Changhui; He, Liansheng; Pei, Yuansheng

    2014-12-01

    Batch experiments were conducted to investigate the phosphorus (P) adsorption and desorption on five drinking water treatment residuals (WTRs) collected from different regions in China. The physical and chemical characteristics of the five WTRs were determined. Combined with rotated principal component analysis, multiple regression analysis was used to analyze the relationship between the inherent properties of the WTRs and their P adsorption capacities. The results showed that the maximum P adsorption capacities of the five WTRs calculated using the Langmuir isotherm ranged from 4.17 to 8.20mg/g at a pH of 7 and further increased with a decrease in pH. The statistical analysis revealed that a factor related to Al and 200 mmol/L oxalate-extractable Al (Alox) accounted for 36.5% of the variations in the P adsorption. A similar portion (28.5%) was attributed to an integrated factor related to the pH, Fe, 200 mmol/L oxalate-extractable Fe (Feox), surface area and organic matter (OM) of the WTRs. However, factors related to other properties (Ca, P and 5 mmol/L oxalate-extractable Fe and Al) were rejected. In addition, the quantity of P desorption was limited and had a significant negative correlation with the (Feox+Alox) of the WTRs (p<0.05). Overall, WTRs with high contents of Alox, Feox and OM as well as large surface areas were proposed to be the best choice for P adsorption in practical applications. Copyright © 2014. Published by Elsevier B.V.

  16. Inherent and passive safety measures in accelerator driven systems: a safety strategy for ADS

    International Nuclear Information System (INIS)

    Maschek, W.; Rineiski, A.; Morita, K.; Flad, M.

    2001-01-01

    The efficiency of Accelerator Driven Systems (ADSs) for the transmutation and incineration of nuclear waste is strongly related to the utilization of so-called dedicated fuels. In the ideal case these fuels should consist of pure TRUs without fertile materials as 238 U or 232 Th to achieve highest incineration/transmutation rates. Dedicated fuels still have to be developed and programs are under way for their fabrication, irradiation and testing. These fertile-free fuels may suffer from deteriorated thermal or thermo-mechanical properties, as a reduced melting point, reduced thermal conductivity or even thermal instability. First analyses have shown that the use of dedicated fuels may lead to a strong deterioration of the safety parameters of the reactor core as e.g. the void worth, the Doppler or the kinetics quantities as neutron generation time and β eff . In addition, a dedicated core may contain multiple ''critical'' fuel masses, resulting in a considerable recriticality potential. Current knowledge on these dedicated fuels suggests that ''critical'' reactors may not be feasible, because of safety reasons. However, for ADSs, the salient hope has been promoted that due to the subcriticality of the system the poor safety features of such fuels could be coped with. Analyses are presented which show potential safety problems for such dedicated cores. Respecting the results of these analyses a safety strategy is proposed along the lines of defense approach in analogy with ideas formerly developed for fast reactors. Inherent and passive safety measures are integrated into the various defense lines. (author)

  17. The hype cycle in 3D displays: inherent limits of autostereoscopy

    Science.gov (United States)

    Grasnick, Armin

    2013-06-01

    Since a couple of years, a renaissance of 3dimensional cinema can be observed. Even though the stereoscopy was quite popular within the last 150 years, the 3d cinema has disappeared and re-established itself several times. The first boom in the late 19th century stagnated and vanished after a few years of success, the same happened again in 50's and 80's of the 20th century. With the commercial success of the 3d blockbuster "Avatar" in 2009, at the latest, it is obvious that the 3d cinema is having a comeback. How long will it last this time? There are already some signs of a declining interest in 3d movies, as the discrepancy between expectations and the results delivered becomes more evident. From the former hypes it is known: After an initial phase of curiosity (high expectations and excessive fault tolerance), a phase of frustration and saturation (critical analysis and subsequent disappointment) will follow. This phenomenon is known as "Hype Cycle" The everyday experienced evolution of technology has conditioned the consumers. The expectation "any technical improvement will preserve all previous properties" cannot be fulfilled with present 3d technologies. This is an inherent problem of stereoscopy and autostereoscopy: The presentation of an additional dimension caused concessions in relevant characteristics (i.e. resolution, brightness, frequency, viewing area) or leads to undesirable physical side effects (i.e. subjective discomfort, eye strain, spatial disorientation, feeling of nausea). It will be verified that the 3d apparatus (3d glasses or 3d display) is also the source for these restrictions and a reason for decreasing fascination. The limitations of present autostereoscopic technologies will be explained.

  18. Ethical issues in the application of genetic engineering | Ukah ...

    African Journals Online (AJOL)

    The position of this paper titled “Ethical Issues in the Application of Genetic Engineering” is that science needs to be overseen by ethics. The science of genetics is used as case study here to highlight the difficulties inherent in the application of the discoveries of geneticists. Whereas we have acknowledged the positive ...

  19. Selective nature and inherent variability of interrill erosion across prolonged rainfall simulation

    Science.gov (United States)

    Hu, Y.; Kuhn, N. J.; Fister, W.

    2012-04-01

    Sediment of interrill erosion has been generally recognized to be selectively enriched with soil organic carbon (SOC) and fine fractions (clay/silt-sized particles or aggregates) in comparison to source area soil. Limited kinetic energy and lack of concentrated runoff are the dominant factors causing selective detachment and transportation. Although enrichment ratios of SOC (ERsoc) in eroded sediment were generally reported > 1, the values varied widely. Causal factors to variation, such as initial soil properties, rainfall properties and experimental conditions, have been extensively discussed. But less attention was directed to the potential influence of prolonged rainfall time onto the temporal pattern of ERsoc. Conservation of mass dictates that ERsoc must be balanced by a decline in the source material which should also lead to a reduced or even negative ERsoc in sediment over time. Besides, the stabilizing effects of structural crust on reducing erosional variation, and the unavoidable variations of erosional response induced by the inherent complexity of interrill erosion, have scarcely been integrated. Moreover, during a prolonged rainfall event surface roughness evolves and affects the movement of eroded aggregates and mineral particles. In this study, two silt loams from Möhlin, Switzerland, organically (OS) and conventionally farmed (CS), were exposed to simulated rainfall of 30 mm h-1 for up to 6 hours. Round donut-flumes with a confined eroding area (1845 cm2) and limited transporting distance (20 cm) were used. Sediments, runoff and subsurface flow were collected in intervals of 30 min. Loose aggregates left on the eroded soil surface, crusts and the soil underneath the crusts were collected after the experiment. All the samples were analyzed for total organic carbon (TOC) content, and texture. Laser scanning of soil surface was applied before and after the rainfall event. The whole experiment was repeated for 10 times. Results from this study showed

  20. MOX-fuel inherent proliferation-protection due to {sup 231}Pa admixture

    Energy Technology Data Exchange (ETDEWEB)

    Kryuchkov, E.F.; Glebov, V.B.; Apse, V.A.; Shmelev, A.N. [Moscow Engineering Physics Institute (State University), Moscow (Russian Federation)

    2003-07-01

    The proliferation protection levels of MOX-fuel containing small additions of protactinium are evaluated for equilibrium closed and open cycles of a light-water reactor (LWR).Analysis of the ways to the proliferation protection of MOX-fuel by small {sup 231}Pa addition and comparison of this way with another options for giving MOX-fuel the proliferation self-protection property enable us to make the 3 following conclusions: -1) Unique nature of protactinium as a small addition to MOX-fuel is determined by the following properties: - Protactinium is available in the nature (uranium ore) as a long-lived mono-isotope {sup 231}Pa, - under neutron irradiation, {sup 231}Pa is converted into {sup 232}U, which is a long-term source of high energy gamma-radiation and practically non-separable from main fuel mass, - essentially, {sup 231}Pa is a high-quality burnable neutron absorber. -2) From the proliferation self-protection point of view, nuclear fuel cycle closure with fuel recycle is a preferable option because, under this condition, introduction of protactinium into MOX-fuel allows to create the inherent radiation barrier which is in action during full cycle of fuel management at the level corresponding to the accepted today criterion of the Spent Fuel Standard (SFS). In particular, the considered example of multiple MOX-fuel recycle with small addition of {sup 231}Pa (0.2% HM) at each cycle demonstrates a possibility to reach the proliferation protection level of fresh MOX-fuel corresponding to once irradiated fuel with the same cooling time. In this case, the lethal dose (at 30 cm distance from fuel assembly) is received within the minute range. -3) Introduction of {sup 231}Pa into MOX-fuel composition in amount of 0.5% HM allows to prolong action of the SFS from 100 to 200 years. If {sup 231}Pa content is increased up to 5% HM, then MOX-fuel conserves the proliferation self-protection property in respect to short-term unauthorized actions for 200-year period of its

  1. Summary of advanced LMR [Liquid Metal Reactor] evaluations: PRISM [Power Reactor Inherently Safe Module] and SAFR [Sodium Advanced Fast Reactor

    International Nuclear Information System (INIS)

    Van Tuyle, G.J.; Slovik, G.C.; Chan, B.C.; Kennett, R.J.; Cheng, H.S.; Kroeger, P.G.

    1989-10-01

    In support of the US Nuclear Regulatory Commission (NRC), Brookhaven National Laboratory (BNL) has performed independent analyses of two advanced Liquid Metal Reactor (LMR) concepts. The designs, sponsored by the US Department of Energy (DOE), the Power Reactor Inherently Safe Module (PRISM) [Berglund, 1987] and the Sodium Advanced Fast Reactor (SAFR) [Baumeister, 1987], were developed primarily by General Electric (GE) and Rockwell International (RI), respectively. Technical support was provided to DOE, RI, and GE, by the Argonne National Laboratory (ANL), particularly with respect to the characteristics of the metal fuels. There are several examples in both PRISM and SAFR where inherent or passive systems provide for a safe response to off-normal conditions. This is in contrast to the engineered safety systems utilized on current US Light Water Reactor (LWR) designs. One important design inherency in the LMRs is the ''inherent shutdown'', which refers to the tendency of the reactor to transition to a much lower power level whenever temperatures rise significantly. This type of behavior was demonstrated in a series of unscrammed tests at EBR-II [NED, 1986]. The second key design feature is the passive air cooling of the vessel to remove decay heat. These systems, designated RVACS in PRISM and RACS in SAFR, always operate and are believed to be able to prevent core damage in the event that no other means of heat removal is available. 27 refs., 78 figs., 3 tabs

  2. The inherence heuristic: an intuitive means of making sense of the world, and a potential precursor to psychological essentialism.

    Science.gov (United States)

    Cimpian, Andrei; Salomon, Erika

    2014-10-01

    We propose that human reasoning relies on an inherence heuristic, an implicit cognitive process that leads people to explain observed patterns (e.g., girls wear pink) predominantly in terms of the inherent features of their constituents (e.g., pink is a delicate color). We then demonstrate how this proposed heuristic can provide a unified account for a broad set of findings spanning areas of research that might at first appear unrelated (e.g., system justification, nominal realism, is-ought errors in moral reasoning). By revealing the deep commonalities among the diverse phenomena that fall under its scope, our account is able to generate new insights into these phenomena, as well as new empirical predictions. A second main goal of this article, aside from introducing the inherence heuristic, is to articulate the proposal that the heuristic serves as a foundation for the development of psychological essentialism. More specifically, we propose that essentialism - which is the common belief that natural and social categories are underlain by hidden, causally powerful essences - emerges over the first few years of life as an elaboration of the earlier, and more open-ended, intuitions supplied by the inherence heuristic. In the final part of the report, we distinguish our proposal from competing accounts (e.g., Strevens's K-laws) and clarify the relationship between the inherence heuristic and related cognitive tendencies (e.g., the correspondence bias). In sum, this article illuminates a basic cognitive process that emerges early in life and is likely to have profound effects on many aspects of human psychology.

  3. Plant-based assessment of inherent soil productivity and contributions to China's cereal crop yield increase since 1980.

    Directory of Open Access Journals (Sweden)

    Mingsheng Fan

    Full Text Available OBJECTIVE: China's food production has increased 6-fold during the past half-century, thanks to increased yields resulting from the management intensification, accomplished through greater inputs of fertilizer, water, new crop strains, and other Green Revolution's technologies. Yet, changes in underlying quality of soils and their effects on yield increase remain to be determined. Here, we provide a first attempt to quantify historical changes in inherent soil productivity and their contributions to the increase in yield. METHODS: The assessment was conducted based on data-set derived from 7410 on-farm trials, 8 long-term experiments and an inventory of soil organic matter concentrations of arable land. RESULTS: Results show that even without organic and inorganic fertilizer addition crop yield from on-farm trials conducted in the 2000s was significantly higher compared with those in the 1980s - the increase ranged from 0.73 to 1.76 Mg/ha for China's major irrigated cereal-based cropping systems. The increase in on-farm yield in control plot since 1980s was due primarily to the enhancement of soil-related factors, and reflected inherent soil productivity improvement. The latter led to higher and stable yield with adoption of improved management practices, and contributed 43% to the increase in yield for wheat and 22% for maize in the north China, and, 31%, 35% and 22% for early and late rice in south China and for single rice crop in the Yangtze River Basin since 1980. CONCLUSIONS: Thus, without an improvement in inherent soil productivity, the 'Agricultural Miracle in China' would not have happened. A comprehensive strategy of inherent soil productivity improvement in China, accomplished through combining engineering-based measures with biological-approaches, may be an important lesson for the developing world. We propose that advancing food security in 21st century for both China and other parts of world will depend on continuously improving

  4. SVBR-75/100 multi-purpose modular inherent-safety fast reactor

    International Nuclear Information System (INIS)

    Dragunov, Yu.G.; Stepanov, V.S.; Klimov, N.N.; Dedul, A.V.; Zrodnokov, A.V.; Toshinsky, G.I.; Komlev, O.G.; Krushelnitsky, V.N.; Takh, S.M.

    2006-01-01

    In this century energy consumption, including electric power, will continue growing on a large scale especially in developing countries. Significant changes in electric power market needs are to be expected in the direction of decreasing and varying the capacity of power sources. To satisfy the expected growth of demand for electric power and to take a decision concerning the ways of further development of global power, including nuclear engineering, it is very important to continue the development of innovative concepts of nuclear power sources, which might successfully compete with alternative power technologies at the future power markets. The proposed nuclear power source (or in other words - reactor plant) of new generation is supposed: - to have small power capacity in the range of 10 - 100 MW (electric) and possibility of its multi-purpose application (independent nuclear power source for desalination installations and electricity supply, nuclear power plants (NPP) of various capacity and purpose; - to use modular principle of construction of NPP of various capacity on the basis of unified 'typical' reactor plants; - to have qualitatively new level of passive safety and possess properties of inherent safety, deterministically excluding any opportunity of severe accidents; - to have an opportunity to use different kinds of fuel and to work in various fuel cycles at various stages of development of nuclear power without change in the design. And also to have long (7-10 years, and in the long term 15-20 years) core life time and enrichment on U-235 not higher than 20 % (which is in compliance with recommendations of IAEA under non-proliferation condition); - to be completely factory-manufactured, and an opportunity of its safe transportation to and from the NPP site shall be provided. Unified multi-purpose reactor plant SVBR-75/100 (Lead-Bismuth Fast Reactor with equivalent electric power of 75 - 100 MW-e depending on the steam parameters) meets the set of the

  5. Inherent Safety Features and Passive Prevention Approaches for Pb/Bi-cooled Accelerator-Driven Systems

    Energy Technology Data Exchange (ETDEWEB)

    Carlsson, Johan

    2003-03-01

    This thesis is devoted to the investigation of passive safety and inherent features of subcritical nuclear transmutation systems - accelerator-driven systems. The general objective of this research has been to improve the safety performance and avoid elevated coolant temperatures in worst-case scenarios like unprotected loss-of-flow accidents, loss-of-heat-sink accidents, and a combination of both these accident initiators. The specific topics covered are emergency decay heat removal by reactor vessel auxiliary cooling systems, beam shut-off by a melt-rupture disc, safety aspects from locating heat-exchangers in the riser of a pool-type reactor system, and reduction of pressure resistance in the primary circuit by employing bypass routes. The initial part of the research was focused on reactor vessel auxiliary cooling systems. It was shown that an 80 MW{sub th} Pb/Bi-cooled accelerator-driven system of 8 m height and 6 m diameter vessel can be well cooled in the case of loss-of-flow accidents in which the accelerator proton beam is not switched off. After a loss-of-heat-sink accident the proton beam has to be interrupted within 40 minutes in order to avoid fast creep of the vessel. If a melt-rupture disc is included in the wall of the beam pipe, which breaks at 150 K above the normal core outlet temperature, the grace period until the beam has to be shut off is increased to 6 hours. For the same vessel geometry, but an operating power of 250 MW{sub th} the structural materials can still avoid fast creep in case the proton beam is shut off immediately. If beam shut-off is delayed, additional cooling methods are needed to increase the heat removal. Investigations were made on the filling of the gap between the guard and the reactor vessel with liquid metal coolant and using water spray cooling on the guard vessel surface. The second part of the thesis presents examinations regarding an accelerator-driven system also cooled with Pb/Bi but with heat-exchangers located

  6. Inherent Safety Features and Passive Prevention Approaches for Pb/Bi-cooled Accelerator-Driven Systems

    International Nuclear Information System (INIS)

    Carlsson, Johan

    2003-03-01

    This thesis is devoted to the investigation of passive safety and inherent features of subcritical nuclear transmutation systems - accelerator-driven systems. The general objective of this research has been to improve the safety performance and avoid elevated coolant temperatures in worst-case scenarios like unprotected loss-of-flow accidents, loss-of-heat-sink accidents, and a combination of both these accident initiators. The specific topics covered are emergency decay heat removal by reactor vessel auxiliary cooling systems, beam shut-off by a melt-rupture disc, safety aspects from locating heat-exchangers in the riser of a pool-type reactor system, and reduction of pressure resistance in the primary circuit by employing bypass routes. The initial part of the research was focused on reactor vessel auxiliary cooling systems. It was shown that an 80 MW th Pb/Bi-cooled accelerator-driven system of 8 m height and 6 m diameter vessel can be well cooled in the case of loss-of-flow accidents in which the accelerator proton beam is not switched off. After a loss-of-heat-sink accident the proton beam has to be interrupted within 40 minutes in order to avoid fast creep of the vessel. If a melt-rupture disc is included in the wall of the beam pipe, which breaks at 150 K above the normal core outlet temperature, the grace period until the beam has to be shut off is increased to 6 hours. For the same vessel geometry, but an operating power of 250 MW th the structural materials can still avoid fast creep in case the proton beam is shut off immediately. If beam shut-off is delayed, additional cooling methods are needed to increase the heat removal. Investigations were made on the filling of the gap between the guard and the reactor vessel with liquid metal coolant and using water spray cooling on the guard vessel surface. The second part of the thesis presents examinations regarding an accelerator-driven system also cooled with Pb/Bi but with heat-exchangers located in the

  7. Issues of power and control in STEM education: a reading through the postmodern condition

    Science.gov (United States)

    Zouda, Majd

    2018-02-01

    STEM, or the integration of science, technology, engineering and mathematics, has rapidly become a dominant discourse in political, economic and educational spheres. In the U.S., the STEM movement has been boosted by global economic-based competition and associated fears, in terms of STEM graduates, when compared with other nations. However, many critiques question the nature and goals of this competition, as well as, the possibilities to improve STEM talents through the current dominant conceptualizations and practices of STEM education. In addition, the apparent lack of significant and coherent embracement of (and sometimes silence about) socioscientific and socio-political issues and perspectives renders STEM education incapable of preparing learners for active citizenships. Building on these critiques, I argue that these problems are possible consequences of STEM as a construct of power. My arguments are based on Lyotard's conceptions of knowledge in postmodern society (as reported in The postmodern condition: A report on knowledge, University Press, Manchester, 1984), which I use to analyze some aspects of the STEM educational movement. Throughout the paper, I explore the construction of STEM education within competitive frames that place prime value on high performativity. There seem to be two characteristics of current STEM education that support performativity; these are an increased focus on technological and engineering designs, and a tendency for interdisciplinary education. At the same time, the eagerness for performativity and competition seems to drag STEM education into selectiveness, thereby jeopardizing its possible benefits. Recommendations are also discussed.

  8. Measurement Model of Reasoning Skills among Science Students Based on Socio Scientific Issues (SSI

    Directory of Open Access Journals (Sweden)

    MOHD AFIFI BAHURUDIN SETAMBAH

    2018-05-01

    Full Text Available The lack of reasoning skills has been recognized as one of the contributing factors to the declined achievement in the Trends in Mathematics and Science Studies (TIMSS and Programme for International Student Assessment (PISA assessments in Malaysia. The use of socio-scientific issues (SSI as a learning strategy offers the potential of improving the level of students' reasoning skills and consequently improves students’ achievement in science subjects. This study examined the development of a measurement model of reasoning skills among science students based on SSI using the analysis of moment structure (AMOS approach before going to second level to full structured equation modelling (SEM. A total of 450 respondents were selected using a stratified random sampling. Results showed a modified measurement model of reasoning skills consisting of the View Knowledge (VK was as a main construct. The items that measure the level of pre-reflection of students fulfilled the elements of unidimensionality, validity, and reliability. Although the level of student reasoning skills was still low but this development of measurement model could be identified and proposed teaching methods that could be adopted to improve students’ reasoning skills.

  9. The Context and Values Inherent in Human Capital as Core Principles for New Economic Theory

    Directory of Open Access Journals (Sweden)

    Winston P. Nagan

    2018-05-01

    Full Text Available This paper has a specific focus on the core foundation of New Economic Theory. That is, the focus on human capital and its implications for the theory and method of the new form of political economy. The central issue that is underlined is the importance of scientific and technological innovation and its necessary interdependence on global values and value analysis. The paper discusses the issue of scientific consciousness as a generator of technological value, and places scientific process at the heart of human consciousness. It discusses the complex interdependence of human relational subjectivity, scientific consciousness, and modern science. The paper draws attention to the problems of observation and participation, and the influence of modern quantum physics in drawing attention to aspects of human consciousness that go beyond the points of conventional science, and open up concern for the principle of non-locality. It explores human subjectivity in terms of the way in which “emotionalized behaviors” have effects on scientific objectivity. It also briefly touches on consciousness and its observable scientific role in the possible reconstruction of some aspects of reality. Mention is made of the Copenhagen perspective, the Many Worlds perspective, and the Penrose interpretation. These insights challenge us to explore human consciousness and innovation in economic organization. The discussion also brings in the principle of relational inter-subjectivity, emotion, and consciousness as a potential driver of human capital and value. In short, positive emotions can influence economic decision-making, as can negative emotions. These challenges stress the problem of human relational subjectivity, values, and technology as the tools to better understand the conflicts and potentials of human capital for New Economic Theory. The issue of value-analysis has both a descriptive and normative dimension. Both of these aspects raise important challenges

  10. A Novel Low Power Bitcell Design Featuring Inherent SEU Prevention and Self Correction Capabilities

    Directory of Open Access Journals (Sweden)

    Oron Chertkow

    2015-06-01

    Full Text Available The pursuit of continuous scaling of electronic devices in the semiconductor industry has led to two unintended but significant outcomes: a rapid increase in susceptibility to radiation induced errors, and an overall rise in power consumption. Operating under low voltage to reduce power only aggravates radiation related reliability issues. The proposed “SEU Hardening Incorporating Extreme Low Power Bitcell Design” (SHIELD addresses these two major concerns simultaneously. It is based on the concept of gating the conventional cross-coupled inverters while introducing a novel “cut-off” network. This creates redundant storage nodes and eliminates the internal feedback loop during radiation particle impact. The SHIELD bitcell tolerates upsets with charge deposits over 1 pC. Simulations confirm its advantages in terms of leakage power, with more than twofold lower leakage currents than previous solutions when operated at a 700mV supply voltage in a 65 nm process. To validate the bitcell’s robustness, several test cases and special concerns, including multiple node upsets (MNU and half-select, are examined.

  11. Apical extrusion of debris: a literature review of an inherent occurrence during root canal treatment.

    Science.gov (United States)

    Tanalp, J; Güngör, T

    2014-03-01

    Extrusion of intracanal debris as well as irrigants is a common occurrence during root canal treatment, and no instrument or technique has thoroughly solved this problem. Because flare-ups may arise with any irritation directed towards periapical tissues, a shaping or irrigation technique should minimize the risk of apical extrusion, even though it may not be prevented. There has been a rapid evolution of root canal instruments and irrigation systems through the last decade, and many have been assessed for their debris extrusion potential. The purpose of this review was to identify publications regarding the evaluation of debris, bacteria and irrigant extrusion during root canal treatment. A PubMed, Ovid and MEDLINE search was conducted using the keywords "apical extrusion", "debris extrusion" and "endodontic treatment". The literature search extended over a period of more than 30 years up to 2012. Content of the review was limited to apical extrusion of debris and irrigants, extrusion of liquid by irrigation methods and bacterial extrusion. Issues relevant to apical extrusion were obtained by further search in the reference sections of the retrieved articles. The review provides an update on the current status of apical extrusion. © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  12. Finite-time and fixed-time leader-following consensus for multi-agent systems with discontinuous inherent dynamics

    Science.gov (United States)

    Ning, Boda; Jin, Jiong; Zheng, Jinchuan; Man, Zhihong

    2018-06-01

    This paper is concerned with finite-time and fixed-time consensus of multi-agent systems in a leader-following framework. Different from conventional leader-following tracking approaches where inherent dynamics satisfying the Lipschitz continuous condition is required, a more generalised case is investigated: discontinuous inherent dynamics. By nonsmooth techniques, a nonlinear protocol is first proposed to achieve the finite-time leader-following consensus. Then, based on fixed-time stability strategies, the fixed-time leader-following consensus problem is solved. An upper bound of settling time is obtained by using a new protocol, and such a bound is independent of initial states, thereby providing additional options for designers in practical scenarios where initial conditions are unavailable. Finally, numerical simulations are provided to demonstrate the effectiveness of the theoretical results.

  13. Increasing Soil Organic Matter Enhances Inherent Soil Productivity while Offsetting Fertilization Effect under a Rice Cropping System

    Directory of Open Access Journals (Sweden)

    Ya-Nan Zhao

    2016-09-01

    Full Text Available Understanding the role of soil organic matter (SOM in soil quality and subsequent crop yield and input requirements is useful for agricultural sustainability. SOM is widely considered to affect a wide range of soil properties, however, great uncertainty still remains in identifying the relationships between SOM and crop yield due to the difficulty in separating the effect of SOM from other yield-limiting factors. Based on 543 on-farm experiments, where paired treatments with and without NPK fertilizer were conducted during 2005–2009, we quantified the inherent soil productivity, fertilization effect, and their contribution to rice yield and further evaluated their relationships with SOM contents under a rice cropping system in the Sichuan Basin of China. The inherent soil productivity assessed by rice grain yield under no fertilization (Y-CK was 5.8 t/ha, on average, and contributed 70% to the 8.3 t/ha of rice yield under NPK fertilization (Y-NPK while the other 30% was from the fertilization effect (FE. No significant correlation between SOM content and Y-NPK was observed, however, SOM content positively related to Y-CK and its contribution to Y-NPK but negatively to FE and its contribution to Y-NPK, indicating an increased soil contribution but a decreased fertilizer contribution to rice yield with increasing SOM. There were significantly positive relationships between SOM and soil available N, P, and K, indicating the potential contribution of SOM to inherent soil productivity by supplying nutrients from mineralization. As a result, approaches for SOM accumulation are practical to improve the inherent soil productivity and thereafter maintain a high crop productivity with less dependence on chemical fertilizers, while fertilization recommendations need to be adjusted with the temporal and spatial SOM variation.

  14. Inherently variable responses to glucocorticoid stress among endogenous retroviruses isolated from 23 mouse strains.

    Science.gov (United States)

    Hsu, Karen; Lee, Young-Kwan; Chew, Alex; Chiu, Sophia; Lim, Debora; Greenhalgh, David G; Cho, Kiho

    2017-10-01

    Active participation of endogenous retroviruses (ERVs) in disease processes has been exemplified by the finding that the HERV (human ERV)-W envelope protein is involved in the pathogenesis of multiple sclerosis, an autoimmune disease. We also demonstrated that injury-elicited stressors alter the expression of murine ERVs (MuERVs), both murine leukemia virus-type and mouse mammary tumor virus (MMTV)-type (MMTV-MuERV). In this study, to evaluate MMTV-MuERVs' responses to stress (e.g., injury, infection)-elicited systemic glucocorticoid (GC) levels, we examined the GC-stress response of 64 MMTV-MuERV promoters isolated from the genomes of 23 mouse strains. All 64 promoters responded to treatment with a synthetic GC, dexamethasone (DEX), at a wide range from a 0.6- to 85.7-fold increase in reporter activity compared to no treatment. An analysis of the 10 lowest and 10 highest DEX responders revealed specific promoter elements exclusively present in either the three lowest or the two highest responders. Each promoter had a unique profile of transcription regulatory elements and the glucocorticoid response element (GRE) was identified in all promoters with the number of GREs ranging from 2 to 7. The three lowest DEX responders were the only promoters with two GREs. The findings from this study suggest that certain MMTV-MuERVs are more responsive to stress-elicited systemic GC elevation compared to the others. The mouse strain-specific genomic MMTV-MuERV profiles and individual MMTV-MuERVs' differential responses to GC-stress might explain, at least in part, the variable inflammatory responses to injury and/or infection, often observed among different mouse strains. This article is part of a Special Issue entitled: Immune and Metabolic Alterations in Trauma and Sepsis edited by Dr. Raghavan Raju. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Subjectivity Inherent In By-Eye Symmetry Judgements and the Large Cutting Tools at the Cave of Hearths, Limpopo Province, South Africa

    Directory of Open Access Journals (Sweden)

    Dave Underhill

    2007-11-01

    Full Text Available The Stone Age of South Africa is an area of study due for a renaissance, and there is a real need for unification of the extant evidence. As a beginning to this, new methodologies have been proposed. This paper tackles the issue of symmetry, specifically the subjectivity involved in by-eye judgements. Assumptions of subjectivity, however, are not proof: presented here is a critical analysis of the inherent bias of by-eye symmetry judgements. Ultimately it is clear that the method contains a level of subjectivity which strips it of any analytical value. The by-eye judgement of symmetry is replaced by the more robust Flip Test computer program, and a brief study is made of the Large Cutting Tools (LCT at a vitally important, yet often overlooked, site dating from the Pleistocene in South Africa, the Cave of Hearths, Limpopo province. The corollary is that the symmetry present in the Cave of Hearths Large Cutting Tools can be studied with some measure of confidence: suggestions are made regarding the nature of tool typologies and the knappers’ ultimate focus on tip shape and utility.

  16. Survey and evaluation of inherent safety characteristics and passive safety systems for use in probabilistic safety analyses

    International Nuclear Information System (INIS)

    Wetzel, N.; Scharfe, A.

    1998-01-01

    The present report examines the possibilities and limits of a probabilistic safety analysis to evaluate passive safety systems and inherent safety characteristics. The inherent safety characteristics are based on physical principles, that together with the safety system lead to no damage. A probabilistic evaluation of the inherent safety characteristic is not made. An inventory of passive safety systems of accomplished nuclear power plant types in the Federal Republic of Germany was drawn up. The evaluation of the passive safety system in the analysis of the accomplished nuclear power plant types was examined. The analysis showed that the passive manner of working was always assumed to be successful. A probabilistic evaluation was not performed. The unavailability of the passive safety system was determined by the failure of active components which are necessary in order to activate the passive safety system. To evaluate the passive safety features in new concepts of nuclear power plants the AP600 from Westinghouse, the SBWR from General Electric and the SWR 600 from Siemens, were selected. Under these three reactor concepts, the SWR 600 is specially attractive because the safety features need no energy sources and instrumentation in this concept. First approaches for the assessment of the reliability of passively operating systems are summarized. Generally it can be established that the core melt frequency for the passive concepts AP600 and SBWR is advantageous in comparison to the probabilistic objectives from the European Pressurized Water Reactor (EPR). Under the passive concepts is the SWR 600 particularly interesting. In this concept the passive systems need no energy sources and instrumentation, and has active operational systems and active safety equipment. Siemens argues that with this concept the frequency of a core melt will be two orders of magnitude lower than for the conventional reactors. (orig.) [de

  17. Making the invisible, visible: challenging the knowledge structures inherent in International Relations Theory in order to create knowledge plural curricula

    Directory of Open Access Journals (Sweden)

    Jacqueline de Matos-Ala

    2018-02-01

    Full Text Available Abstract This article problematizes the lack of plurality of knowledges in International Relations theory curricula. The increase in knowledges and scholarship from the South has not seemingly filtered into International Relations theory curricula significantly. Thus Western knowledges still dominates the narrative. It investigates how knowledge structures inherent in the discipline coupled with Western centric ontology and epistemology function to exclude or marginalize knowledge that does not conform to specific criteria. I demonstrate how the third year IR theory curriculum at Wits University, has engaged with discipline’s knowledge structures as well as its ontology and epistemology to develop a knowledge plural curricula.

  18. 1H NMR-based metabolic profiling reveals inherent biological variation in yeast and nematode model systems

    International Nuclear Information System (INIS)

    Szeto, Samuel S. W.; Reinke, Stacey N.; Lemire, Bernard D.

    2011-01-01

    The application of metabolomics to human and animal model systems is poised to provide great insight into our understanding of disease etiology and the metabolic changes that are associated with these conditions. However, metabolomic studies have also revealed that there is significant, inherent biological variation in human samples and even in samples from animal model systems where the animals are housed under carefully controlled conditions. This inherent biological variability is an important consideration for all metabolomics analyses. In this study, we examined the biological variation in 1 H NMR-based metabolic profiling of two model systems, the yeast Saccharomyces cerevisiae and the nematode Caenorhabditis elegans. Using relative standard deviations (RSD) as a measure of variability, our results reveal that both model systems have significant amounts of biological variation. The C. elegans metabolome possesses greater metabolic variance with average RSD values of 29 and 39%, depending on the food source that was used. The S. cerevisiae exometabolome RSD values ranged from 8% to 12% for the four strains examined. We also determined whether biological variation occurs between pairs of phenotypically identical yeast strains. Multivariate statistical analysis allowed us to discriminate between pair members based on their metabolic phenotypes. Our results highlight the variability of the metabolome that exists even for less complex model systems cultured under defined conditions. We also highlight the efficacy of metabolic profiling for defining these subtle metabolic alterations.

  19. The inherent dynamics of a molecular liquid: Geodesic pathways through the potential energy landscape of a liquid of linear molecules

    Science.gov (United States)

    Jacobson, Daniel; Stratt, Richard M.

    2014-05-01

    Because the geodesic pathways that a liquid follows through its potential energy landscape govern its slow, diffusive motion, we suggest that these pathways are logical candidates for the title of a liquid's "inherent dynamics." Like their namesake "inherent structures," these objects are simply features of the system's potential energy surface and thus provide views of the system's structural evolution unobstructed by thermal kinetic energy. This paper shows how these geodesic pathways can be computed for a liquid of linear molecules, allowing us to see precisely how such molecular liquids mix rotational and translational degrees of freedom into their dynamics. The ratio of translational to rotational components of the geodesic path lengths, for example, is significantly larger than would be expected on equipartition grounds, with a value that scales with the molecular aspect ratio. These and other features of the geodesics are consistent with a picture in which molecular reorientation adiabatically follows translation—molecules largely thread their way through narrow channels available in the potential energy landscape.

  20. Inherent unsharpness of neutron radiographic image on X-ray films; Notranja neostrina nevtronografke slike na roentgenskih filmih

    Energy Technology Data Exchange (ETDEWEB)

    Ilic, R; Najzer, M [Institut Jozef Stefan, Ljubljana (Yugoslavia)

    1979-07-01

    The inherent unsharpness of the AGFA GEVART Structurix D-4 X-ray film was determined in terms of the unsharpness of the image of the knife edge test object for Gd converter 25 {mu}m In converters 50, 150 and 250 {mu}m and by Dy converters 7, 12, 25 and 60 {mu}m thick. The unsharpness of single coated film for Gd converter was found to be 56{+-}5 {mu}m. For In and Dy a value of 230 {+-} was obtained which was found to be independent on the converter type or thickness at least in the range of measuring error. The Inherent unsharpness of double coated film was 440 {+-} for In and 550{+-}50 {mu}m for Dy converter and was not dependent on the converter thickness. Comparing with single coated film the sensitivity was for a factor 1.6 higher for In and Dy converters. For Gd converter there was no gain in sensitivity and even the contrast was worse due to higher gamma ray background. (author)

  1. {sup 1}H NMR-based metabolic profiling reveals inherent biological variation in yeast and nematode model systems

    Energy Technology Data Exchange (ETDEWEB)

    Szeto, Samuel S. W.; Reinke, Stacey N.; Lemire, Bernard D., E-mail: bernard.lemire@ualberta.ca [University of Alberta, Department of Biochemistry, School of Molecular and Systems Medicine (Canada)

    2011-04-15

    The application of metabolomics to human and animal model systems is poised to provide great insight into our understanding of disease etiology and the metabolic changes that are associated with these conditions. However, metabolomic studies have also revealed that there is significant, inherent biological variation in human samples and even in samples from animal model systems where the animals are housed under carefully controlled conditions. This inherent biological variability is an important consideration for all metabolomics analyses. In this study, we examined the biological variation in {sup 1}H NMR-based metabolic profiling of two model systems, the yeast Saccharomyces cerevisiae and the nematode Caenorhabditis elegans. Using relative standard deviations (RSD) as a measure of variability, our results reveal that both model systems have significant amounts of biological variation. The C. elegans metabolome possesses greater metabolic variance with average RSD values of 29 and 39%, depending on the food source that was used. The S. cerevisiae exometabolome RSD values ranged from 8% to 12% for the four strains examined. We also determined whether biological variation occurs between pairs of phenotypically identical yeast strains. Multivariate statistical analysis allowed us to discriminate between pair members based on their metabolic phenotypes. Our results highlight the variability of the metabolome that exists even for less complex model systems cultured under defined conditions. We also highlight the efficacy of metabolic profiling for defining these subtle metabolic alterations.

  2. Feasibility study of a dedicate nuclear desalination system: Low-pressure inherent heat sink nuclear desalination plant (LIND)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ho Sik; No, Hee Cheon; Jo, Yu Gwan; Wivisono, Andhika Feri; Park, Byung Ha; Choi, Jin Young; Lee, Jeong Ik; Jeong, Yong Hoon; Cho, Nam Zin [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2015-04-15

    In this paper, we suggest the conceptual design of a water-cooled reactor system for a low-pressure inherent heat sink nuclear desalination plant (LIND) that applies the safety-related design concepts of high temperature gas-cooled reactors to a water-cooled reactor for inherent and passive safety features. Through a scoping analysis, we found that the current LIND design satisfied several essential thermal-hydraulic and neutronic design requirements. In a thermal-hydraulic analysis using an analytical method based on the Wooton-Epstein correlation, we checked the possibility of safely removing decay heat through the steel containment even if all the active safety systems failed. In a neutronic analysis using the Monte Carlo N-particle transport code, we estimated a cycle length of approximately 6 years under 200 MW{sub th} and 4.5% enrichment. The very long cycle length and simple safety features minimize the burdens from the operation, maintenance, and spent-fuel management, with a positive impact on the economic feasibility. Finally, because a nuclear reactor should not be directly coupled to a desalination system to prevent the leakage of radioactive material into the desalinated water, three types of intermediate systems were studied: a steam producing system, a hot water system, and an organic Rankine cycle system.

  3. Feasibility study of a dedicated nuclear desalination system: Low-pressure Inherent heat sink Nuclear Desalination plant (LIND

    Directory of Open Access Journals (Sweden)

    Ho Sik Kim

    2015-04-01

    Full Text Available In this paper, we suggest the conceptual design of a water-cooled reactor system for a low-pressure inherent heat sink nuclear desalination plant (LIND that applies the safety-related design concepts of high temperature gas-cooled reactors to a water-cooled reactor for inherent and passive safety features. Through a scoping analysis, we found that the current LIND design satisfied several essential thermal–hydraulic and neutronic design requirements. In a thermal–hydraulic analysis using an analytical method based on the Wooton–Epstein correlation, we checked the possibility of safely removing decay heat through the steel containment even if all the active safety systems failed. In a neutronic analysis using the Monte Carlo N-particle transport code, we estimated a cycle length of approximately 6 years under 200 MWth and 4.5% enrichment. The very long cycle length and simple safety features minimize the burdens from the operation, maintenance, and spent-fuel management, with a positive impact on the economic feasibility. Finally, because a nuclear reactor should not be directly coupled to a desalination system to prevent the leakage of radioactive material into the desalinated water, three types of intermediate systems were studied: a steam producing system, a hot water system, and an organic Rankine cycle system.

  4. Structural Integrity and Aging-Related Issues of Helicopters

    Science.gov (United States)

    2000-10-01

    inherently damage lolerant , any damage- inspection in critical locations where tests have indicated tolerant features in airframe design only enhances...required, so European Rotorcraft Forum. Marseilles, France, 15- that helicopters are equipped with such features as fly- 17 September 1998 . by-wire and...fatigue Evaluation of structural integrity issues of aging helicopters. The Structure," 29 April, 1998 . extended safe-life approach encompasses the best

  5. Operation Inherent Resolve

    Science.gov (United States)

    2015-04-01

    a revised certification with Jordan’s Water Author- ity to inform funding decisions, in particular, for a new plant in Tafilah Governorate worth...Germany Moldova Slovakia Bahrain Greece Montenegro Slovenia Belgium Hungary Morocco Somalia Bosnia and Herzegovina Iceland The Netherlands...treatment plant in Tafilah Governorate worth about $18 million. Certification is required by Section 611(e) of the Foreign Assistance Act of 1961, as

  6. Nuclear deterrence: Inherent escalation?

    International Nuclear Information System (INIS)

    Bergbauer, J.R. Jr.

    1993-01-01

    Despite 40 years of peace between the super powers, there is increasing clamor to the effect that nuclear war between the super powers is imminent; or could occur through escalation from a minor conflict; or could result from harsh rhetoric (but only on the part of the U.S.) in the super power dialogue. The factor that is ignored is that a massive nuclear attack would be rational ONLY if that attack could inflict such damage that the other super power could not launch a significant retaliatory nuclear attack. ONLY in this circumstance would there be any profit in launching an initial Strategic Nuclear Attack. This First Strike capability is not now possessed nor projected to be developed by either super power. As long as ANY possible Strategic Nuclear Attack against the national territory of one super power would be insufficient to prevent an equally destructive retaliatory attack, then a Strategic Nuclear Attack would inevitably result in the destruction of both and would be profitless, hence, pointless. This situation describes Mutually Assured Destruction (MAD), the governing conflict paradigm applicable to both super powers. The only convential attack that would even remotely rival the national-destruction potential of a Strategic Nuclear Attack and could cause the attacked power to consider launching a retaliatory Strategic Nuclear Attack would be a massive land-air invasion/occupation of one super power by the other. Since neither super power can successfully execute such a conventional invasion/occupation, this situation is moot. The geo-political environments of the two super powers are so asymmetrical and their military positions so symmetrical that the probability of ANY forseeable situation resulting in their resorting to a Strategic Nuclear Exchange is vanishingly small. It is possible escape the Chicken-Little syndrome and, instead, devote energy to ensuring the maintenance of this favorable, but fragile, world system

  7. Characterization of Inherent Particles and Mechanism of Thermal Stress Induced Particle Formation in HSV-2 Viral Vaccine Candidate.

    Science.gov (United States)

    Li, Lillian; Kirkitadze, Marina; Bhandal, Kamaljit; Roque, Cristopher; Yang, Eric; Carpick, Bruce; Rahman, Nausheen

    2017-11-10

    Vaccine formulations may contain visible and/or subvisible particles, which can vary in both size and morphology. Extrinsic particles, which are particles not part of the product such as foreign contaminants, are generally considered undesirable and should be eliminated or controlled in injectable products. However, biological products, in particular vaccines, may also contain particles that are inherent to the product. Here we focus on the characterization of visible and subvisible particles in a live, replication-deficient viral vaccine candidate against HSV genital herpes in an early developmental stage. HSV-2 viral vaccine was characterized using a panel of analytical methods, including Fourier transform infrared spectroscopy (FTIR), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Western blot, liquid chromatography-mass spectrometry (LC-MS), light microscopy, transmission electron microscopy (TEM), micro-flow imaging (MFI), dynamic light scattering (DLS), right angle light scattering (RALS), and intrinsic fluorescence. Particles in HSV-2 vaccine typically ranged from hundreds of nanometers to hundreds of micrometers in size and were determined to be inherent to the product. The infectious titer did not correlate with any trend in subvisible particle concentration and size distribution as shown by DLS, MFI, and TEM under stressed conditions. This suggested that particle changes in the submicron range were related to HSV-2 virion structure and had direct impact on biological activity. It was also observed that subvisible and visible particles could induce aggregation in the viral product. The temperature induced aggregation was observed by RALS, intrinsic fluorescence, and DLS. The increase of subvisible particle size with temperature could be fitted to a two-step thermokinetic model. Visible and subvisible particles were found to be inherent to the HSV-2 viral vaccine product. The mechanism of protein aggregation was discussed and a two

  8. Effect of x-ray treatments on pathogenic bacteria, inherent microbiota, color, and texture on parsley leaves.

    Science.gov (United States)

    Mahmoud, Barakat S M

    2012-10-01

    This work is a part of systematic studies of the effect of X-ray treatments on fresh produce. The main objective of this investigation was to study the effects of X-ray treatments in reducing the concentration of artificially inoculated Escherichia coli O157:H7, Listeria monocytogenes, Salmonella enterica, and Shigella flexneri, and inherent microbiota on parsley leaves. The secondary objective was to study the effects of X-ray treatments on color and texture parameters on treated parsley leaves. The Dip-inoculated method was used to inoculate parsley leaves with a mixture of two or three strains of each tested organism at 10(8) to 10(9) colony-forming unit (CFU)/mL; the inoculated parsley leaves were then air-dried and followed by treatment with different doses of X-ray (0, 0.1, 0.5, 1.0, and 1.5 kGy) at 22°C and 55-60% relative humidity. Surviving bacterial populations on parsley leaves were evaluated using a nonselective medium (tryptic soy agar) with a selective medium overlay for each bacterium: E. coli O157:H7 (CT-SMAC agar), L. monocytogenes (MOA), and S. enterica and S. flexneri (XLD). Approximately 5.8, 3.1, 5.7, and 5.2 log CFU reductions of E. coli O157:H7, L. monocytogenes, S. enterica, and Shigella flexneri were achieved by treatment with 1.0 kGy X-ray, respectively. Furthermore, the populations of E. coli O157:H7, L. monocytogenes, S. enterica, and Shigella flexneri were reduced to less than the detectable limit (1.0 log CFU/g) by treatment with 1.5 kGy X-ray. Treatment with 1.5 kGy X-ray significantly reduced the initial inherent microbiota on parsley leaves, and inherent levels were significantly (p 0.05) in color or texture of control and treated samples with 0.1-1.5 X-ray were observed. The results of investigation indicated that X-ray is an effective technology to eliminate E. coli O157:H7, L. monocytogenes, S. enterica, and Shigella flexneri, and to extend the shelf life of parsley leaves.

  9. Research Article Special Issue

    African Journals Online (AJOL)

    2016-05-15

    May 15, 2016 ... Near-fault earthquake issue is almost a new issue in earthquake engineering. ... although those countries had advanced regulations for seismic design of ... allocating the plastic joints according to development guideline and ...

  10. Future accelerators: physics issues

    International Nuclear Information System (INIS)

    Bjorken, J.D.

    1977-11-01

    High energy physics of the future using future accelerators is discussed. The proposed machines and instruments, physics issues and opportunities including brief sketches of outstanding recent results, and the way the proposed machines address these issues are considered. 42 references

  11. Medical Issues: Orthopedics

    Science.gov (United States)

    ... Information Packets Equipment Pool Living With SMA Medical Issues Palliative Breathing Orthopedics Nutrition Equipment Daily Life At ... curesma.org > support & care > living with sma > medical issues > orthopedics Orthopedics In SMA, muscle weakness can cause ...

  12. Medical Issues: Equipment

    Science.gov (United States)

    ... Information Packets Equipment Pool Living With SMA Medical Issues Palliative Breathing Orthopedics Nutrition Equipment Daily Life At ... curesma.org > support & care > living with sma > medical issues > equipment Equipment Individuals with SMA often require a ...

  13. Health Issues and Treatments

    Science.gov (United States)

    ... About Us Information For… Media Policy Makers Health Issues & Treatments Language: English (US) Español (Spanish) Recommend on ... people with spina bifida are exactly alike. Health issues and treatments for people with spina bifida will ...

  14. Medical Issues: Breathing

    Science.gov (United States)

    ... Information Packets Equipment Pool Living With SMA Medical Issues Palliative Breathing Orthopedics Nutrition Equipment Daily Life At ... curesma.org > support & care > living with sma > medical issues > breathing Breathing Breathing problems are the most common ...

  15. Space Station Engineering Design Issues

    Science.gov (United States)

    Mcruer, Duane T.; Boehm, Barry W.; Debra, Daniel B.; Green, C. Cordell; Henry, Richard C.; Maycock, Paul D.; Mcelroy, John H.; Pierce, Chester M.; Stafford, Thomas P.; Young, Laurence R.

    1989-01-01

    Space Station Freedom topics addressed include: general design issues; issues related to utilization and operations; issues related to systems requirements and design; and management issues relevant to design.

  16. A model for roll stall and the inherent stability modes of low aspect ratio wings at low Reynolds numbers

    Science.gov (United States)

    Shields, Matt

    The development of Micro Aerial Vehicles has been hindered by the poor understanding of the aerodynamic loading and stability and control properties of the low Reynolds number regime in which the inherent low aspect ratio (LAR) wings operate. This thesis experimentally evaluates the static and damping aerodynamic stability derivatives to provide a complete aerodynamic model for canonical flat plate wings of aspect ratios near unity at Reynolds numbers under 1 x 105. This permits the complete functionality of the aerodynamic forces and moments to be expressed and the equations of motion to solved, thereby identifying the inherent stability properties of the wing. This provides a basis for characterizing the stability of full vehicles. The influence of the tip vortices during sideslip perturbations is found to induce a loading condition referred to as roll stall, a significant roll moment created by the spanwise induced velocity asymmetry related to the displacement of the vortex cores relative to the wing. Roll stall is manifested by a linearly increasing roll moment with low to moderate angles of attack and a subsequent stall event similar to a lift polar; this behavior is not experienced by conventional (high aspect ratio) wings. The resulting large magnitude of the roll stability derivative, Cl,beta and lack of roll damping, Cl ,rho, create significant modal responses of the lateral state variables; a linear model used to evaluate these modes is shown to accurately reflect the solution obtained by numerically integrating the nonlinear equations. An unstable Dutch roll mode dominates the behavior of the wing for small perturbations from equilibrium, and in the presence of angle of attack oscillations a previously unconsidered coupled mode, referred to as roll resonance, is seen develop and drive the bank angle? away from equilibrium. Roll resonance requires a linear time variant (LTV) model to capture the behavior of the bank angle, which is attributed to the

  17. Prostaglandin E2 enhances long-term repopulation but does not permanently alter inherent stem cell competitiveness.

    Science.gov (United States)

    Hoggatt, Jonathan; Mohammad, Khalid S; Singh, Pratibha; Pelus, Louis M

    2013-10-24

    Hematopoietic stem cell (HSC) transplantation is a lifesaving therapy for malignant and nonmalignant hematologic diseases and metabolic disorders. Although successful, hematopoietic transplantation can be hindered by inadequate stem cell number or poor engrafting efficiency. To overcome these deficits, we and others have previously reported the HSC-enhancing ability of a short-term exposure of prostaglandin E2 (PGE2); this strategy has now progressed to phase 1 clinical trials in double cord blood transplantation. To further analyze the short- and long-term effects of HSC exposure to PGE2, we followed the repopulation kinetics of PGE2-treated hematopoietic grafts through 5 serial transplantations and compared inherent long-term competitiveness in a HSC head-to-head secondary transplantation model. Treatment with PGE2 did not result in a long-term increase in HSC competitiveness, lineage bias, or enhanced proliferative potential, demonstrating that pulse exposure to PGE2 results in transient increases in HSC homing and engraftment potential.

  18. Inherent Electrochemistry and Charge Transfer Properties of Few-Layer Two Dimensional Ti3C2Tx MXene

    KAUST Repository

    Nayak, Pranati

    2018-05-25

    We report the effect of Ti3C2Tx MXene flake thickness on its inherent electrochemistry and heterogeneous charge transfer characteristics. It is shown that the Ti3C2Tx undergoes irreversible oxidation in the positive potential window, which strongly depends on the flake thickness and pH of the electrolyte. Few-layer Ti3C2Tx exhibits faster electron transfer kinetics (k0=0.09533 cm/s) with Fe(CN)64−/3− redox mediator compared to multi-layer Ti3C2Tx (k0= 0.00503 cm/s). In addition, few-layer free standing Ti3C2Tx film electrode remains intact after enduring irreversible oxidation.

  19. Movie Popularity Classification based on Inherent Movie Attributes using C4.5, PART and Correlation Coefficient

    DEFF Research Database (Denmark)

    Ibnal Asad, Khalid; Ahmed, Tanvir; Rahman, Md. Saiedur

    2012-01-01

    Abundance of movie data across the internet makes it an obvious candidate for machine learning and knowledge discovery. But most researches are directed towards bi-polar classification of movie or generation of a movie recommendation system based on reviews given by viewers on various internet...... sites. Classification of movie popularity based solely on attributes of a movie i.e. actor, actress, director rating, language, country and budget etc. has been less highlighted due to large number of attributes that are associated with each movie and their differences in dimensions. In this paper, we...... propose classification scheme of pre-release movie popularity based on inherent attributes using C4.S and PART classifier algorithm and define the relation between attributes of post release movies using correlation coefficient....

  20. Generating millimeter-wave Bessel beam with orbital angular momentum using reflective-type metasurface inherently integrated with source

    Science.gov (United States)

    Shen, Yizhu; Yang, Jiawei; Meng, Hongfu; Dou, Wenbin; Hu, Sanming

    2018-04-01

    Metasurfaces, orbital angular momenta (OAM), and non-diffractive Bessel beams have been attracting worldwide research. Combining the benefits of these three promising techniques, this paper proposes a metasurface-based reflective-type approach to generate a first-order Bessel beam carrying OAM. To validate this approach, a millimeter-wave metasurface is analyzed, designed, fabricated, and measured. Experimental results agree well with simulation. Moreover, this reflective-type metasurface, generating a Bessel beam with OAM, is inherently integrated with a planar feeding source in the same single-layer printed circuit board. Therefore, the proposed design features low profile, low cost, easy integration with front-end active circuits, and no alignment error between the feeding source and the metasurface.