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Sample records for perspectives structural problems

  1. Alternative Perspectives on Risk: Individual Differences in Problem Structuring

    NASA Technical Reports Server (NTRS)

    Orasanu, Judith; Fischer, Ute; Connors, Mary M. (Technical Monitor)

    1997-01-01

    Team decision making involves contributions of multiple players toward a common goal. While much has been written about the importance of developing shared mental models in order for teams to work together effectively, little has been done to determine the value of alternative perspectives on problem solving and decision making. Early studies of expertise contrasted experts with novices and noted that the two groups differ in the way they structure problems and in their selection of information as salient. Little attention has been given to differences among experts who differ in their specializations. A series of experiments was conducted to determine: (1) what dimensions of flight-related problem situations pilots judge to be most important when making flight-relevant decisions; and (2) whether pilots in different crew positions differ in the way they interpret problems relating to flight decisions. A sorting task was used to identify underlying dimensions judged as salient to individual pilots. Captains, first officers, and flight engineers from two major carriers participated in the study. Twenty-two flight scenarios were developed based on ASRS reports. Pilots were required to make judgments about how they would respond in each case and to sort the scenarios on the basis of similarity of decision factors. They were also asked to provide a verbal label that described each of their sorted categories. A second study required a different group of pilots (also captains, first officers and flight engineers) to sort on predetermined bases.

  2. Algorithmic Perspectives on Problem Formulations in MDO

    NASA Technical Reports Server (NTRS)

    Alexandrov, Natalia M.; Lewis, Robert Michael

    2000-01-01

    This work is concerned with an approach to formulating the multidisciplinary optimization (MDO) problem that reflects an algorithmic perspective on MDO problem solution. The algorithmic perspective focuses on formulating the problem in light of the abilities and inabilities of optimization algorithms, so that the resulting nonlinear programming problem can be solved reliably and efficiently by conventional optimization techniques. We propose a modular approach to formulating MDO problems that takes advantage of the problem structure, maximizes the autonomy of implementation, and allows for multiple easily interchangeable problem statements to be used depending on the available resources and the characteristics of the application problem.

  3. Comparing Multiple Solutions in the Structured Problem Solving: Deconstructing Japanese Lessons from Learner's Perspective

    ERIC Educational Resources Information Center

    Hino, Keiko

    2015-01-01

    The purpose of this study is to enhance our understanding of how students listen and attend to multiple solutions proposed by their classmates during the activity of comparison. This study examines ten consecutive lessons in each of the two eighth-grade classrooms in Tokyo that are organized in the style of "structured problem solving".…

  4. Problem-Framing: A perspective on environmental problem-solving

    NASA Astrophysics Data System (ADS)

    Bardwell, Lisa V.

    1991-09-01

    The specter of environmental calamity calls for the best efforts of an involved public. Ironically, the way people understand the issues all too often serves to discourage and frustrate rather than motivate them to action. This article draws from problem-solving perspectives offered by cognitive psychology and conflict management to examine a framework for thinking about environmental problems that promises to help rather than hinder efforts to address them. Problem-framing emphasizes focusing on the problem definition. Since how one defines a problem determines one's understanding of and approach to that problem, being able to redefine or reframe a problem and to explore the “problem space” can help broaden the range of alternatives and solutions examined. Problem-framing incorporates a cognitive perspective on how people respond to information. It explains why an emphasis on problem definition is not part of people's typical approach to problems. It recognizes the importance of structure and of having ways to organize that information on one's problem-solving effort. Finally, problem-framing draws on both cognitive psychology and conflict management for strategies to manage information and to create a problem-solving environment that not only encourages participation but can yield better approaches to our environmental problems.

  5. Perspectives on Problem Solving and Instruction

    ERIC Educational Resources Information Center

    van Merrienboer, Jeroen J. G.

    2013-01-01

    Most educators claim that problem solving is important, but they take very different perspective on it and there is little agreement on how it should be taught. This article aims to sort out the different perspectives and discusses problem solving as a goal, a method, and a skill. As a goal, problem solving should not be limited to well-structured…

  6. Theoretical and Philosophical Perspectives to Problem Solving.

    ERIC Educational Resources Information Center

    Sherman, Thomas M.; And Others

    1988-01-01

    Five articles explore various theoretical aspects of problems and problem solving skills. Highlights include strategies to learn problem solving skills; knowledge structures; metacognition; behavioral processes and cognitive psychology; erotetic logic; creativity as an aspect of computer problem solving; and programing as a problem-solving…

  7. [Addiction therapy. Limits, problems, perspectives].

    PubMed

    Kalapos, Miklós Péter

    2014-01-01

    In health care, tending is a process, which offers for the patients a continuous watching on, a control, a treatment, and the prevention of worsening of their medical status as well as the reduction of their complaints. In the article, some fundamental segments of tending in addictology are reviewed, particularly paying attention to whom, how, where and how long to take care. On the basis of literature, the author stresses whatever method is used to treat addict patients it is more beneficial to society than the avoidance of any intervention due to the negligence of the problem. Addictology has lost a lot from its power in Hungary. The author recommends the introduction of the methods of health quality assurance to decrease the effect of negative trends seen in addictology. The paper also deals with special patient groups including homeless clients, adolescents, elderly and pregnant patients as well as health care professionals. The author critically mentions the double communication of society, the dual-face character of politics and has the opinion that competences are not clear making the situation confused. As a mistake of the point of view is it regarded that the addictological problems are classified as to belonging to the authority of psychiatry. It is emphasized that multidisciplinary approach is needed to understand the problem and to treat the client. General screening for addictological diseases does not seem possible in the light of low capacity of the system, but the screening of adolescents and pregnant women is definitely recommended. And finally, a financial support for medicines to prevent craving, a moratorium for the continuous changing of rules and law, the sponsoring of harm reduction programs as well as a better utilization of opportunities offered by local drug coordinating boards are proposed.

  8. [Addiction therapy. Limits, problems, perspectives].

    PubMed

    Kalapos, Miklós Péter

    2014-01-01

    In health care, tending is a process, which offers for the patients a continuous watching on, a control, a treatment, and the prevention of worsening of their medical status as well as the reduction of their complaints. In the article, some fundamental segments of tending in addictology are reviewed, particularly paying attention to whom, how, where and how long to take care. On the basis of literature, the author stresses whatever method is used to treat addict patients it is more beneficial to society than the avoidance of any intervention due to the negligence of the problem. Addictology has lost a lot from its power in Hungary. The author recommends the introduction of the methods of health quality assurance to decrease the effect of negative trends seen in addictology. The paper also deals with special patient groups including homeless clients, adolescents, elderly and pregnant patients as well as health care professionals. The author critically mentions the double communication of society, the dual-face character of politics and has the opinion that competences are not clear making the situation confused. As a mistake of the point of view is it regarded that the addictological problems are classified as to belonging to the authority of psychiatry. It is emphasized that multidisciplinary approach is needed to understand the problem and to treat the client. General screening for addictological diseases does not seem possible in the light of low capacity of the system, but the screening of adolescents and pregnant women is definitely recommended. And finally, a financial support for medicines to prevent craving, a moratorium for the continuous changing of rules and law, the sponsoring of harm reduction programs as well as a better utilization of opportunities offered by local drug coordinating boards are proposed. PMID:25411227

  9. Food sustainability: problems, perspectives and solutions.

    PubMed

    Garnett, Tara

    2013-02-01

    The global food system makes a significant contribution to climate changing greenhouse gas emissions with all stages in the supply chain, from agricultural production through processing, distribution, retailing, home food preparation and waste, playing a part. It also gives rise to other major environmental impacts, including biodiversity loss and water extraction and pollution. Policy makers are increasingly aware of the need to address these concerns, but at the same time they are faced with a growing burden of food security and nutrition-related problems, and tasked with ensuring that there is enough food to meet the needs of a growing global population. In short, more people need to be fed better, with less environmental impact. How might this be achieved? Broadly, three main 'takes' or perspectives, on the issues and their interactions, appear to be emerging. Depending on one's view point, the problem can be conceptualised as a production challenge, in which case there is a need to change how food is produced by improving the unit efficiency of food production; a consumption challenge, which requires changes to the dietary drivers that determine food production; or a socio-economic challenge, which requires changes in how the food system is governed. This paper considers these perspectives in turn, their implications for nutrition and climate change, and their strengths and weaknesses. Finally, an argument is made for a reorientation of policy thinking which uses the insights provided by all three perspectives, rather than, as is the situation today, privileging one over the other. PMID:23336559

  10. Food sustainability: problems, perspectives and solutions.

    PubMed

    Garnett, Tara

    2013-02-01

    The global food system makes a significant contribution to climate changing greenhouse gas emissions with all stages in the supply chain, from agricultural production through processing, distribution, retailing, home food preparation and waste, playing a part. It also gives rise to other major environmental impacts, including biodiversity loss and water extraction and pollution. Policy makers are increasingly aware of the need to address these concerns, but at the same time they are faced with a growing burden of food security and nutrition-related problems, and tasked with ensuring that there is enough food to meet the needs of a growing global population. In short, more people need to be fed better, with less environmental impact. How might this be achieved? Broadly, three main 'takes' or perspectives, on the issues and their interactions, appear to be emerging. Depending on one's view point, the problem can be conceptualised as a production challenge, in which case there is a need to change how food is produced by improving the unit efficiency of food production; a consumption challenge, which requires changes to the dietary drivers that determine food production; or a socio-economic challenge, which requires changes in how the food system is governed. This paper considers these perspectives in turn, their implications for nutrition and climate change, and their strengths and weaknesses. Finally, an argument is made for a reorientation of policy thinking which uses the insights provided by all three perspectives, rather than, as is the situation today, privileging one over the other.

  11. Individual therapy for couple problems: perspectives and pitfalls.

    PubMed

    Gurman, Alan S; Burton, Mark

    2014-10-01

    Despite the demonstrated efficacy of conjoint couple therapy, many clients seeking help for couple problems ultimately find themselves in individual therapy for these concerns. Individual therapy for couple problems (ITCP) may evolve from a partner's refusal of conjoint therapy or from the treatment format preferences of either the client or therapist. Having acknowledged the role of partner refusals, we offer some perspectives about the idiosyncratic personal factors and professional background factors that may lead therapists to provide ITCP and discuss the significant pitfalls in its practice. We emphasize five central areas of concern in the ongoing practice of ITCP: structural constraints on change; therapist side-taking and the therapeutic alliance; inaccurate assessments based on individual client reports; therapeutic focus; and ethical issues relevant to both attending and nonattending partners. We conclude by urging that this very important but largely neglected topic be paid greater attention in psychotherapy research, training and continuing education. PMID:24773422

  12. A Set-Oriented Perspective on Solving Counting Problems

    ERIC Educational Resources Information Center

    Lockwood, Elise

    2014-01-01

    In this article, I present the notion of a set-oriented perspective for solving counting problems that emerged during task-based interviews with postsecondary students. Framing the findings within Harel's "ways of thinking", I argue that students may benefit from this perspective, in which they view attending to sets of outcomes as…

  13. New Perspectives on Human Problem Solving

    ERIC Educational Resources Information Center

    Goldstone, Robert L.; Pizlo, Zygmunt

    2009-01-01

    In November 2008 at Purdue University, the 2nd Workshop on Human Problem Solving was held. This workshop, which was a natural continuation of the first workshop devoted almost exclusively to optimization problems, addressed a wider range of topics that reflect the scope of the "Journal of Problem Solving." The workshop was attended by 35…

  14. Perspectives on the consecutive pages problem

    NASA Astrophysics Data System (ADS)

    Srinivasan, V. K.

    2011-04-01

    This article presents different approaches to a problem, dubbed by the author as 'the consecutive pages problem'. The aim of this teaching-oriented article is to promote the teaching of abstract concepts in mathematics, by selecting a challenging amusement problem and then presenting various solutions in such a way that it can engage the attention of a fourth-grade student, a high school senior student, an average college student and scholars.

  15. Dynamic Problem Solving: A New Assessment Perspective

    ERIC Educational Resources Information Center

    Greiff, Samuel; Wustenberg, Sascha; Funke, Joachim

    2012-01-01

    This article addresses two unsolved measurement issues in dynamic problem solving (DPS) research: (a) unsystematic construction of DPS tests making a comparison of results obtained in different studies difficult and (b) use of time-intensive single tasks leading to severe reliability problems. To solve these issues, the MicroDYN approach is…

  16. Rio Grande rift: problems and perspectives

    SciTech Connect

    Baldridge, W.S.; Olsen, K.H.; Callender, J.F.

    1984-01-01

    Topics and ideas addressed include: (1) the regional extent of the Rio Grande rift; (2) the structure of the crust and upper mantle; (3) whether the evidence for an axile dike in the lower crust is compelling; (4) the nature of faulting and extension in the crust; and (5) the structural and magmatic development of the rift. 88 references, 5 figures.

  17. PREFACE: The random search problem: trends and perspectives The random search problem: trends and perspectives

    NASA Astrophysics Data System (ADS)

    da Luz, Marcos G. E.; Grosberg, Alexander; Raposo, Ernesto P.; Viswanathan, Gandhi M.

    2009-10-01

    very important to solve computationally complex problems (e.g., protein folding), which involve optimizations in very high dimensional energy landscapes. On the other hand, random searches can also be studied from the perspective of diffusion and transport properties which is an important topic in condensed matter and statistical physics. For instance, the features of light scattered in a media, where the scatterers have a power-law distribution of sizes in many aspects, may resemble the patterns generated by a searcher performing Lévy walks. There are many questions related to random searches: how the searcher moves or should move, what are the patterns generated during the locomotion, how do the encounter rates depend on parameters of the search, etc. But perhaps, the most well known issue is how to optimize the search for specific target scenarios. The optimization can be in either continuous or discrete environments, when the information available is limited. The answer to this question determines specific strategies of movement that would maximize some properly defined search efficiency measure. The relevance of the question stems from the fact that the strategy-dynamics represents one of the most important factors that modulate the rate of encounters (e.g., the encounter rate between predator and prey). In the general context, strategy choices can be essential in determining the outcome and thus the success of a given search. For instance, realistic searches—and locomotion in general—require the expenditure of energy. Thus, inefficient search could deplete energy reserves (e.g., fat) and lead to rates of encounters below a minimum acceptable threshold (resulting in extinction of a species, for example). The framework of the random search `game' distinguishes between the two interacting players in a context of pursuit and chance. They are either a `searcher' (e.g., predator, protein, radar, `crawler') or a `target' (e.g., prey, DNA sequence, a missing

  18. A geometrical perspective for the bargaining problem.

    PubMed

    Wong, Kelvin Kian Loong

    2010-01-01

    A new treatment to determine the Pareto-optimal outcome for a non-zero-sum game is presented. An equilibrium point for any game is defined here as a set of strategy choices for the players, such that no change in the choice of any single player will increase the overall payoff of all the players. Determining equilibrium for multi-player games is a complex problem. An intuitive conceptual tool for reducing the complexity, via the idea of spatially representing strategy options in the bargaining problem is proposed. Based on this geometry, an equilibrium condition is established such that the product of their gains over what each receives is maximal. The geometrical analysis of a cooperative bargaining game provides an example for solving multi-player and non-zero-sum games efficiently. PMID:20436675

  19. Solving Math Problems Approximately: A Developmental Perspective

    PubMed Central

    Ganor-Stern, Dana

    2016-01-01

    Although solving arithmetic problems approximately is an important skill in everyday life, little is known about the development of this skill. Past research has shown that when children are asked to solve multi-digit multiplication problems approximately, they provide estimates that are often very far from the exact answer. This is unfortunate as computation estimation is needed in many circumstances in daily life. The present study examined 4th graders, 6th graders and adults’ ability to estimate the results of arithmetic problems relative to a reference number. A developmental pattern was observed in accuracy, speed and strategy use. With age there was a general increase in speed, and an increase in accuracy mainly for trials in which the reference number was close to the exact answer. The children tended to use the sense of magnitude strategy, which does not involve any calculation but relies mainly on an intuitive coarse sense of magnitude, while the adults used the approximated calculation strategy which involves rounding and multiplication procedures, and relies to a greater extent on calculation skills and working memory resources. Importantly, the children were less accurate than the adults, but were well above chance level. In all age groups performance was enhanced when the reference number was smaller (vs. larger) than the exact answer and when it was far (vs. close) from it, suggesting the involvement of an approximate number system. The results suggest the existence of an intuitive sense of magnitude for the results of arithmetic problems that might help children and even adults with difficulties in math. The present findings are discussed in the context of past research reporting poor estimation skills among children, and the conditions that might allow using children estimation skills in an effective manner. PMID:27171224

  20. Nigeria's internal petroleum problems: perspectives and choices

    SciTech Connect

    Iwayemi, A.

    1984-10-01

    Oil-producing Nigeria has been hard hit by weakening oil markets, the replacement of the civilian government by a military regime, and sporadic but severe energy supply problems. The latter included shortages of petroleum products and irregular availability of electricity. These conditions will worsen unless Nigeria takes immediate action to introduce demand management, including efficient pricing and other conservation measures, and timely investment to expand domestic energy facilities, change the institutional and policy environment, and assure the availability of imported supplies. It is also important to encourage the development of renewable energy sources. 16 references, 2 tables.

  1. Problems in Children's Peer Relations: A Broadening Perspective.

    ERIC Educational Resources Information Center

    Burton, Christine B.

    Examined are recent advances in knowledge about children with peer relationship problems. Two specific developments are described: (1) an emerging recognition of the differences that exist between socially rejected versus neglected children; and (2) a growing appreciation for children's own perspectives on their social situations. The discussion…

  2. [Problems and perspectives in child health care].

    PubMed

    Nikolić, N; Gebauer, E; Jovanović, M; Rakić, D; Katanić, D

    1997-01-01

    Health care protection of children in Vojvodina is of particular importance regarding the negative natural birth rate. In spite of difficult economic situation, health care of children in Vojvodina is permanently carried out and would be significantly better in quality if the education of subspecialized personnel, space facilities, technological innovations, computerization and continuous education were available. Introduction of microanalytic laboratory techniques is essential for monitoring of prematures. Propagation of natural nutrition is an obligation of pediatricians. Respiratory diseases are still on the top of morbidity pyramid but tuberculosis is evidently in increase. An important health care problem is the expansion of allergic diseases. The progressive incidence of insulin-dependent diabetes is also evident. The spheres of juvenile gynecological endocrinology and andrology are still underdeveloped and that also applies to adolescent medicine. Toxicology remains an ongoing problem in pediatrics due to an increased number of accidental poisoning. Pediatricians-gastroenterologists are lacking while paediatric hepatology should be brought into more advanced state. Bone marrow and stem cells transplantation is in the responsibility of the Centre for haematology and oncology. Nephrology department lacks children's haemodialysis, ultrasound biopsy of kidneys, urodynamic analyses and new staff facilities. The increased number of survivals in case of children with with sequeles inevitably asks for better development of rehabilitation, prolonged treatment and teamwork. Intensive care and therapy department requires new staff and high technology capacities. Development of children's surgery department inevitably means the reconstruction of space facilities, modern equipment and new subspecializations. Preventive outpatient service is performed through systematic examinations. ultrasound diagnostics of hips, auditive screening and educational program activities

  3. Problems of Teaching the Behaviorist Perspective in the Cognitive Revolution

    PubMed Central

    Abramson, Charles I.

    2013-01-01

    This article offers some personal reflections on the difficulty of teaching the behaviorist perspective in the psychology classroom. The problems focus on the inadequacy of introductory textbooks—which mischaracterize behaviorism, only present the most extreme behaviorist positions, make no mention of the neobehaviorist perspective, fail to discuss that there is no accepted criteria for determining what type of behavior is cognitive, and provide a definition of cognition that is, not only inconsistent across texts, but so broad as to overshadow the behaviorist contributions. Suggestions are provided for instructors on how to present to their students an accurate portrayal of behaviorism. PMID:25379226

  4. Problems of teaching the behaviorist perspective in the cognitive revolution.

    PubMed

    Abramson, Charles I

    2013-03-01

    This article offers some personal reflections on the difficulty of teaching the behaviorist perspective in the psychology classroom. The problems focus on the inadequacy of introductory textbooks-which mischaracterize behaviorism, only present the most extreme behaviorist positions, make no mention of the neobehaviorist perspective, fail to discuss that there is no accepted criteria for determining what type of behavior is cognitive, and provide a definition of cognition that is, not only inconsistent across texts, but so broad as to overshadow the behaviorist contributions. Suggestions are provided for instructors on how to present to their students an accurate portrayal of behaviorism. PMID:25379226

  5. Problem Structure and Performance on Two-Step Word Problems.

    ERIC Educational Resources Information Center

    Hocevar, Dennis; And Others

    1987-01-01

    The effects of problem structure on two-step word problems are analyzed in a sample of 91 fifth through eighth graders. Results showed that sequencing the first and second steps did not cause as much trouble as understanding the first step. (RB)

  6. PREFACE: The random search problem: trends and perspectives The random search problem: trends and perspectives

    NASA Astrophysics Data System (ADS)

    da Luz, Marcos G. E.; Grosberg, Alexander; Raposo, Ernesto P.; Viswanathan, Gandhi M.

    2009-10-01

    very important to solve computationally complex problems (e.g., protein folding), which involve optimizations in very high dimensional energy landscapes. On the other hand, random searches can also be studied from the perspective of diffusion and transport properties which is an important topic in condensed matter and statistical physics. For instance, the features of light scattered in a media, where the scatterers have a power-law distribution of sizes in many aspects, may resemble the patterns generated by a searcher performing Lévy walks. There are many questions related to random searches: how the searcher moves or should move, what are the patterns generated during the locomotion, how do the encounter rates depend on parameters of the search, etc. But perhaps, the most well known issue is how to optimize the search for specific target scenarios. The optimization can be in either continuous or discrete environments, when the information available is limited. The answer to this question determines specific strategies of movement that would maximize some properly defined search efficiency measure. The relevance of the question stems from the fact that the strategy-dynamics represents one of the most important factors that modulate the rate of encounters (e.g., the encounter rate between predator and prey). In the general context, strategy choices can be essential in determining the outcome and thus the success of a given search. For instance, realistic searches—and locomotion in general—require the expenditure of energy. Thus, inefficient search could deplete energy reserves (e.g., fat) and lead to rates of encounters below a minimum acceptable threshold (resulting in extinction of a species, for example). The framework of the random search `game' distinguishes between the two interacting players in a context of pursuit and chance. They are either a `searcher' (e.g., predator, protein, radar, `crawler') or a `target' (e.g., prey, DNA sequence, a missing

  7. Parenting Education in Australia: A Structural Perspective.

    ERIC Educational Resources Information Center

    Allan, June

    This paper offers critical reflections on parenting education in its social context. The paper is informed by a feminist perspective, and by a structural approach to practice that emphasizes the importance of changing social structures. An introductory section explores the impact of the ideologies of the traditional family, and of motherhood and…

  8. Structured problem solving for materiel managers.

    PubMed

    Samelson, Q B

    1998-05-01

    A structured approach to problem solving and solution documentation is one of the keys to continuous improvement. Without it, it is quite possible to solve the wrong problem, to solve the right problem in the wrong way, or (maybe worst of all) to solve the same problem over and over again. Companies that have figured out how to solve the right problems in the right way, once and for all, will ultimately move forward much faster than their competitors.

  9. Nursing Instructor and Students’ Perspectives on Clinical Education Apprenticeship Problems

    PubMed Central

    Hasanpour-Dehkordi, Ali

    2016-01-01

    Introduction Different problems might lead to reduction in the efficiency of nursing students’ apprenticeship education and solving those problems. Aim This study was conducted to determine nursing internship problems from the perspective of trainers and students. Materials and Methods In this descriptive cross-sectional study, 20 trainers and 43 senior students of nursing were selected using census method. A researcher-made questionnaire was used to collect data. Total internal consistency (α) of the questionnaire was 0.88 and had proper convergent validity. SPSS was used to analyse data with applying descriptive and inferential statistics. Results More than 50% considered their course relatively weak or weak in helping intern nurses to acquire comprehensive view of the nursing profession that takes a social perspective into account, skills required for the processes of nursing and instructing patients. Problems such as insufficient access to welfare and educational facilities, lack of co-operation among clinical team and scattering of internship sessions during a course were mentioned by nurses and their trainers. They believed that changes must take place in the way internship courses are carried out. Conclusion Although the internship courses seem to achieve their aim of improving students’ skills and independence in providing different nursing services to students and their trainers generally have a positive attitude towards such courses, there are still problems in effective exercise of the training. PMID:27790467

  10. Glutathione transferases: a structural perspective.

    PubMed

    Oakley, Aaron

    2011-05-01

    The glutathione transferases (GSTs) are one of the most important families of detoxifying enzymes in nature. The classic activity of the GSTs is conjugation of compounds with electrophilic centers to the tripeptide glutathione (GSH), but many other activities are now associated with GSTs, including steroid and leukotriene biosynthesis, peroxide degradation, double-bond cis-trans isomerization, dehydroascorbate reduction, Michael addition, and noncatalytic "ligandin" activity (ligand binding and transport). Since the first GST structure was determined in 1991, there has been an explosion in structural data across GSTs of all three families: the cytosolic GSTs, the mitochondrial GSTs, and the membrane-associated proteins in eicosanoid and glutathione metabolism (MAPEG family). In this review, the major insights into GST structure and function will be discussed.

  11. Perceived organizational problems in health care: a pilot test of the structured problem and success inventory.

    PubMed

    Nyström, Monica E; Terris, Darcey D; Sparring, Vibeke; Tolf, Sara; Brown, Claire R

    2012-01-01

    Our objective was to test whether the Structured Problem and Success Inventory (SPI) instrument could capture mental representations of organizational and work-related problems as described by individuals working in health care organizations and to test whether these representations varied according to organizational position. A convenience sample (n = 56) of middle managers (n = 20), lower-level managers (n = 20), and staff (n = 16) from health care organizations in Stockholm (Sweden) attending organizational development courses during 2003-2004 was recruited. Participants used the SPI to describe the 3 most pressing organizational and work-related problems. Data were systematically reviewed to identify problem categories and themes. One hundred sixty-four problems were described, clustered into 13 problem categories. Generally, middle managers focused on organizational factors and managerial responsibilities, whereas lower-level managers and staff focused on operational issues and what others did or ought to do. Furthermore, we observed similarities and variation in perceptions and their association with respondents' position within an organization. Our results support the need for further evaluation of the SPI as a promising tool for health care organizations. Collecting structured inventories of organizational and work-related problems from multiple perspectives may assist in the development of shared understandings of organizational challenges and lead to more effective and efficient processes of solution planning and implementation.

  12. Structural Perspective on Enzymatic Halogenation

    PubMed Central

    2008-01-01

    Simple halogen substituents frequently afford key structural features that account for the potency and selectivity of natural products, including antibiotics and hormones. For example, when a single chlorine atom on the antibiotic vancomycin is replaced by hydrogen, the resulting antibacterial activity decreases by up to 70% (HarrisC. M.; KannanR.; KopeckaH.; HarrisT. M.J. Am. Chem. Soc.1985, 107, 6652−6658). This Account analyzes how structure underlies mechanism in halogenases, the molecular machines designed by nature to incorporate halogens into diverse substrates. Traditional synthetic methods of integrating halogens into complex molecules are often complicated by a lack of specificity and regioselectivity. Nature, however, has developed a variety of elegant mechanisms for halogenating specific substrates with both regio- and stereoselectivity. An improved understanding of the biological routes toward halogenation could lead to the development of novel synthetic methods for the creation of new compounds with enhanced functions. Already, researchers have co-opted a fluorinase from the microorganism Streptomyces cattleya to produce 18F-labeled molecules for use in positron emission tomography (PET) (DengH.; CobbS. L.; GeeA. D.; LockhartA.; MartarelloL.; McGlincheyR. P.; O’HaganD.; OnegaM.Chem. Commun.2006, 652−654). Therefore, the discovery and characterization of naturally occurring enzymatic halogenation mechanisms has become an active area of research. The catalogue of known halogenating enzymes has expanded from the familiar haloperoxidases to include oxygen-dependent enzymes and fluorinases. Recently, the discovery of a nucleophilic halogenase that catalyzes chlorinations has expanded the repertoire of biological halogenation chemistry (DongC.; HuangF.; DengH.; SchaffrathC.; SpencerJ. B.; O’HaganD.; NaismithJ. H.Nature2004, 427, 561−56514765200). Structural characterization has provided a basis toward a mechanistic understanding of the specificity

  13. Structural damage assessment as an identification problem

    NASA Technical Reports Server (NTRS)

    Hajela, Prabhat; Soeiro, F. J.

    1989-01-01

    Damage assessment of structural assemblies is treated as an identification problem. A brief review of identification methods is first presented with particular focus on the output error approach. The use of numerical optimization methods in identifying the location and extent of damage in structures is studied. The influence of damage on eigenmode shapes and static displacements is explored as a means of formulating a measure of damage in the structure. Preliminary results obtained in this study are presented and special attention is directed at the shortcomings associated with the nonlinear programming approach to solving the optimization problem.

  14. Structural perspectives on secondary active transporters

    PubMed Central

    Boudker, Olga; Verdon, Grégory

    2010-01-01

    Secondary active transporters catalyze concentrative transport of substrates across lipid membranes by harnessing the energy of electrochemical ion gradients. These transporters bind their ligands on one side of the membrane, and undergo a global conformational change to release them on the other side of the membrane. Over the last few years, crystal structures have captured several bacterial secondary transporters in different states along their transport cycle, providing insight into possible molecular mechanisms. In this review, we will summarize recent findings focusing on the emerging structural and mechanistic similarities between evolutionary diverse transporters. We will also discuss the structural basis of substrate binding, ion coupling and inhibition viewed from the perspective of these similarities. PMID:20655602

  15. Unifying Temporal and Structural Credit Assignment Problems

    NASA Technical Reports Server (NTRS)

    Agogino, Adrian K.; Tumer, Kagan

    2004-01-01

    Single-agent reinforcement learners in time-extended domains and multi-agent systems share a common dilemma known as the credit assignment problem. Multi-agent systems have the structural credit assignment problem of determining the contributions of a particular agent to a common task. Instead, time-extended single-agent systems have the temporal credit assignment problem of determining the contribution of a particular action to the quality of the full sequence of actions. Traditionally these two problems are considered different and are handled in separate ways. In this article we show how these two forms of the credit assignment problem are equivalent. In this unified frame-work, a single-agent Markov decision process can be broken down into a single-time-step multi-agent process. Furthermore we show that Monte-Carlo estimation or Q-learning (depending on whether the values of resulting actions in the episode are known at the time of learning) are equivalent to different agent utility functions in a multi-agent system. This equivalence shows how an often neglected issue in multi-agent systems is equivalent to a well-known deficiency in multi-time-step learning and lays the basis for solving time-extended multi-agent problems, where both credit assignment problems are present.

  16. PERSPECTIVE VIEW OF THE STONEMASONRY STRUCTURE FOUND DURING DEMOLITION OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PERSPECTIVE VIEW OF THE STONEMASONRY STRUCTURE FOUND DURING DEMOLITION OF DOUGLAS FIR INTERPRETIVE SITE, VIEW LOOKING NORTH. - Oregon State Forester's Office Complex, 2600 State Street, Salem, Marion, OR

  17. Two-particle problem in comblike structures

    NASA Astrophysics Data System (ADS)

    Agliari, Elena; Cassi, Davide; Cattivelli, Luca; Sartori, Fabio

    2016-05-01

    Encounters between walkers performing a random motion on an appropriate structure can describe a wide variety of natural phenomena ranging from pharmacokinetics to foraging. On homogeneous structures the asymptotic encounter probability between two walkers is (qualitatively) independent of whether both walkers are moving or one is kept fixed. On infinite comblike structures this is no longer the case and here we deepen the mechanisms underlying the emergence of a finite probability that two random walkers will never meet, while one single random walker is certain to visit any site. In particular, we introduce an analytical approach to address this problem and even more general problems such as the case of two walkers with different diffusivity, particles walking on a finite comb and on arbitrary bundled structures, possibly in the presence of loops. Our investigations are both analytical and numerical and highlight that, in general, the outcome of a reaction involving two reactants on a comblike architecture can strongly differ according to whether both reactants are moving (no matter their relative diffusivities) or only one is moving and according to the density of shortcuts among the branches.

  18. Two-particle problem in comblike structures.

    PubMed

    Agliari, Elena; Cassi, Davide; Cattivelli, Luca; Sartori, Fabio

    2016-05-01

    Encounters between walkers performing a random motion on an appropriate structure can describe a wide variety of natural phenomena ranging from pharmacokinetics to foraging. On homogeneous structures the asymptotic encounter probability between two walkers is (qualitatively) independent of whether both walkers are moving or one is kept fixed. On infinite comblike structures this is no longer the case and here we deepen the mechanisms underlying the emergence of a finite probability that two random walkers will never meet, while one single random walker is certain to visit any site. In particular, we introduce an analytical approach to address this problem and even more general problems such as the case of two walkers with different diffusivity, particles walking on a finite comb and on arbitrary bundled structures, possibly in the presence of loops. Our investigations are both analytical and numerical and highlight that, in general, the outcome of a reaction involving two reactants on a comblike architecture can strongly differ according to whether both reactants are moving (no matter their relative diffusivities) or only one is moving and according to the density of shortcuts among the branches. PMID:27300834

  19. The relativistic inverse stellar structure problem

    SciTech Connect

    Lindblom, Lee

    2014-01-14

    The observable macroscopic properties of relativistic stars (whose equations of state are known) can be predicted by solving the stellar structure equations that follow from Einstein’s equation. For neutron stars, however, our knowledge of the equation of state is poor, so the direct stellar structure problem can not be solved without modeling the highest density part of the equation of state in some way. This talk will describe recent work on developing a model independent approach to determining the high-density neutron-star equation of state by solving an inverse stellar structure problem. This method uses the fact that Einstein’s equation provides a deterministic relationship between the equation of state and the macroscopic observables of the stars which are composed of that material. This talk illustrates how this method will be able to determine the high-density part of the neutron-star equation of state with few percent accuracy when high quality measurements of the masses and radii of just two or three neutron stars become available. This talk will also show that this method can be used with measurements of other macroscopic observables, like the masses and tidal deformabilities, which can (in principle) be measured by gravitational wave observations of binary neutron-star mergers.

  20. Current structural vibration problems associated with noise

    NASA Technical Reports Server (NTRS)

    Mixson, J. S.

    1974-01-01

    As the performance of aerospace vehicles has increased, the noise generated by the propulsion system and by the passage of the vehicle through the air has also increased. Further increases in performance are now underway for space vehicles such as the space shuttle vehicle and for short distance takeoff and landing (STOL) aircraft, and are being planned for supersonic aircraft. The flight profiles and design features of these high-performance vehicles are reviewed and an estimate made of selected noise-induced structural vibration problems. Considerations for the prevention of acoustic fatigue, noise transmission, and electronic instrument malfunction are discussed.

  1. Computational strategies to address chromatin structure problems

    NASA Astrophysics Data System (ADS)

    Perišić, Ognjen; Schlick, Tamar

    2016-06-01

    While the genetic information is contained in double helical DNA, gene expression is a complex multilevel process that involves various functional units, from nucleosomes to fully formed chromatin fibers accompanied by a host of various chromatin binding enzymes. The chromatin fiber is a polymer composed of histone protein complexes upon which DNA wraps, like yarn upon many spools. The nature of chromatin structure has been an open question since the beginning of modern molecular biology. Many experiments have shown that the chromatin fiber is a highly dynamic entity with pronounced structural diversity that includes properties of idealized zig-zag and solenoid models, as well as other motifs. This diversity can produce a high packing ratio and thus inhibit access to a majority of the wound DNA. Despite much research, chromatin’s dynamic structure has not yet been fully described. Long stretches of chromatin fibers exhibit puzzling dynamic behavior that requires interpretation in the light of gene expression patterns in various tissue and organisms. The properties of chromatin fiber can be investigated with experimental techniques, like in vitro biochemistry, in vivo imagining, and high-throughput chromosome capture technology. Those techniques provide useful insights into the fiber’s structure and dynamics, but they are limited in resolution and scope, especially regarding compact fibers and chromosomes in the cellular milieu. Complementary but specialized modeling techniques are needed to handle large floppy polymers such as the chromatin fiber. In this review, we discuss current approaches in the chromatin structure field with an emphasis on modeling, such as molecular dynamics and coarse-grained computational approaches. Combinations of these computational techniques complement experiments and address many relevant biological problems, as we will illustrate with special focus on epigenetic modulation of chromatin structure.

  2. Perspective-Taking in Structured and Unstructured Online Discussions

    ERIC Educational Resources Information Center

    Chadwick, Scott; Ralston, Ekaterina

    2010-01-01

    This study analyzes the extent to which students using web-based discussion boards show an increase in perspective-taking in structured and unstructured discussions. Messages from fifty-six students enrolled in one of two courses were content analyzed using Jarvela and Hakkinen's (2003) expansion of Selman's (1980) perspective-taking coding…

  3. Reading Multimodal Texts: Perceptual, Structural and Ideological Perspectives

    ERIC Educational Resources Information Center

    Serafini, Frank

    2010-01-01

    This article presents a tripartite framework for analyzing multimodal texts. The three analytical perspectives presented include: (1) perceptual, (2) structural, and (3) ideological analytical processes. Using Anthony Browne's picturebook "Piggybook" as an example, assertions are made regarding what each analytical perspective brings to the…

  4. Firefighter Hand Anthropometry and Structural Glove Sizing: A New Perspective

    PubMed Central

    Hsiao, Hongwei; Whitestone, Jennifer; Kau, Tsui-Ying; Hildreth, Brooke

    2015-01-01

    Objective We evaluated the current use and fit of structural firefighting gloves and developed an improved sizing scheme that better accommodates the U.S. firefighter population. Background Among surveys, 24% to 30% of men and 31% to 62% of women reported experiencing problems with the fit or bulkiness of their structural firefighting gloves. Method An age-, race/ethnicity-, and gender-stratified sample of 863 male and 88 female firefighters across the United States participated in the study. Fourteen hand dimensions relevant to glove design were measured. A cluster analysis of the hand dimensions was performed to explore options for an improved sizing scheme. Results The current national standard structural firefighting glove-sizing scheme underrepresents firefighter hand size range and shape variation. In addition, mismatch between existing sizing specifications and hand characteristics, such as hand dimensions, user selection of glove size, and the existing glove sizing specifications, is significant. An improved glove-sizing plan based on clusters of overall hand size and hand/finger breadth-to-length contrast has been developed. Conclusion This study presents the most up-to-date firefighter hand anthropometry and a new perspective on glove accommodation. The new seven-size system contains narrower variations (standard deviations) for almost all dimensions for each glove size than the current sizing practices. Application The proposed science-based sizing plan for structural firefighting gloves provides a step-forward perspective (i.e., including two women hand model–based sizes and two wide-palm sizes for men) for glove manufacturers to advance firefighter hand protection. PMID:26169309

  5. Team-Based Complex Problem Solving: A Collective Cognition Perspective

    ERIC Educational Resources Information Center

    Hung, Woei

    2013-01-01

    Today, much problem solving is performed by teams, rather than individuals. The complexity of these problems has exceeded the cognitive capacity of any individual and requires a team of members to solve them. The success of solving these complex problems not only relies on individual team members who possess different but complementary expertise,…

  6. Problem Solving in the School Curriculum from a Design Perspective

    ERIC Educational Resources Information Center

    Toh, Tin Lam; Leong, Yew Hoong; Dindyal, Jaguthsing; Quek, Khiok Seng

    2010-01-01

    In this symposium, the participants discuss some preliminary data collected from their problem solving project which uses a design experiment approach. Their approach to problem solving in the school curriculum is in tandem with what Schoenfeld (2007) claimed: "Crafting instruction that would make a wide range of problem-solving strategies…

  7. Human pharmaceutical products in the environment - the "problem" in perspective.

    PubMed

    Taylor, David; Senac, Thomas

    2014-11-01

    Concerns about the potential for significant environmental impact from residues of human pharmaceuticals emerged at the beginning of the 21st century. Since then there has been an exponential rise in the number of publications and conferences on this "problem". However, this intense focus on human pharmaceuticals is misplaced. Pharmaceuticals do not consist of a coherent group of substances with similar chemical, structural, biological or toxicological properties. Pharmaceuticals are only identifiable from their use: in other words substances can be divided into two classes, those that are used as pharmaceuticals and those for which a possible pharmaceutical use has not yet been discovered. For example, nitro-glycerine, Warfarin and dimethyl fumarate, initially sold respectively as an explosive, a rodenticide and a mould inhibitor have subsequently all been used as pharmaceuticals. As analytical science advances, an increasing range of environmental contaminants, including pharmaceuticals, is being identified at sub μgL(-1) concentrations. Although, human and environmental exposure to these contaminants will be low, all of them need to be subjected to risk assessment on a case by case basis. Many of these substances, including human pharmaceuticals, may have little, if any, impact on human health or the environment, however for some substances there may be a significant risk and in these cases appropriate action should be taken. However considering all human pharmaceuticals as a special case, isolated from the wider range of emerging contaminants, is scientifically unjustifiable and diverts resources away from the consideration of other substances that may be of considerably more significance.

  8. Sound absorption by subwavelength membrane structures: A geometric perspective

    NASA Astrophysics Data System (ADS)

    Yang, Min; Li, Yong; Meng, Chong; Fu, Caixing; Mei, Jun; Yang, Zhiyu; Sheng, Ping

    2015-12-01

    Decorated membranes comprising a thin layer of elastic film with small rigid platelets fixed on top have been found to be efficient absorbers of low-frequency sound. In this work we consider the problem of sound absorption from a perspective aimed at deriving upper bounds under different scenarios, i.e., whether the sound is incident from one side only or from both sides, and whether there is a reflecting surface on the back side of the membrane. By considering the negligible thickness of the membrane, usually on the order of a fraction of one millimeter, we derive a relation showing that the sum of the incoming sound waves' (complex) pressure amplitudes, averaged over the area of the membrane, must be equal to that of the outgoing waves. By using this relation, and without going to any details of the wave solutions, it is shown that the maximum absorption achievable from one-sided incidence is 50%, while the maximum absorption with a back-reflecting surface can reach 100%. The latter was attained by the hybridized resonances. All the results are shown to be in excellent agreement with the experiments. This generalized perspective, when used together with the Green function's formalism, can be useful in gaining insights into the constraints on what are achievable in scatterings and absorption by thin film structures and delineating them.

  9. PERSPECTIVE VIEW OF THE STONEMASONRY STRUCTURE FOUND UNDERNEATH THE DOUGLAS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PERSPECTIVE VIEW OF THE STONEMASONRY STRUCTURE FOUND UNDERNEATH THE DOUGLAS FIR INTERPRETIVE SITE AFTER DEMOLITION, VIEW LOOKING NORTHWEST. - Oregon State Forester's Office Complex, 2600 State Street, Salem, Marion, OR

  10. The Perspective Structure of Visual Space.

    PubMed

    Erkelens, Casper J

    2015-10-01

    Luneburg's model has been the reference for experimental studies of visual space for almost seventy years. His claim for a curved visual space has been a source of inspiration for visual scientists as well as philosophers. The conclusion of many experimental studies has been that Luneburg's model does not describe visual space in various tasks and conditions. Remarkably, no alternative model has been suggested. The current study explores perspective transformations of Euclidean space as a model for visual space. Computations show that the geometry of perspective spaces is considerably different from that of Euclidean space. Collinearity but not parallelism is preserved in perspective space and angles are not invariant under translation and rotation. Similar relationships have shown to be properties of visual space. Alley experiments performed early in the nineteenth century have been instrumental in hypothesizing curved visual spaces. Alleys were computed in perspective space and compared with reconstructed alleys of Blumenfeld. Parallel alleys were accurately described by perspective geometry. Accurate distance alleys were derived from parallel alleys by adjusting the interstimulus distances according to the size-distance invariance hypothesis. Agreement between computed and experimental alleys and accommodation of experimental results that rejected Luneburg's model show that perspective space is an appropriate model for how we perceive orientations and angles. The model is also appropriate for perceived distance ratios between stimuli but fails to predict perceived distances. PMID:27648222

  11. The Perspective Structure of Visual Space.

    PubMed

    Erkelens, Casper J

    2015-10-01

    Luneburg's model has been the reference for experimental studies of visual space for almost seventy years. His claim for a curved visual space has been a source of inspiration for visual scientists as well as philosophers. The conclusion of many experimental studies has been that Luneburg's model does not describe visual space in various tasks and conditions. Remarkably, no alternative model has been suggested. The current study explores perspective transformations of Euclidean space as a model for visual space. Computations show that the geometry of perspective spaces is considerably different from that of Euclidean space. Collinearity but not parallelism is preserved in perspective space and angles are not invariant under translation and rotation. Similar relationships have shown to be properties of visual space. Alley experiments performed early in the nineteenth century have been instrumental in hypothesizing curved visual spaces. Alleys were computed in perspective space and compared with reconstructed alleys of Blumenfeld. Parallel alleys were accurately described by perspective geometry. Accurate distance alleys were derived from parallel alleys by adjusting the interstimulus distances according to the size-distance invariance hypothesis. Agreement between computed and experimental alleys and accommodation of experimental results that rejected Luneburg's model show that perspective space is an appropriate model for how we perceive orientations and angles. The model is also appropriate for perceived distance ratios between stimuli but fails to predict perceived distances.

  12. The Perspective Structure of Visual Space

    PubMed Central

    2015-01-01

    Luneburg’s model has been the reference for experimental studies of visual space for almost seventy years. His claim for a curved visual space has been a source of inspiration for visual scientists as well as philosophers. The conclusion of many experimental studies has been that Luneburg’s model does not describe visual space in various tasks and conditions. Remarkably, no alternative model has been suggested. The current study explores perspective transformations of Euclidean space as a model for visual space. Computations show that the geometry of perspective spaces is considerably different from that of Euclidean space. Collinearity but not parallelism is preserved in perspective space and angles are not invariant under translation and rotation. Similar relationships have shown to be properties of visual space. Alley experiments performed early in the nineteenth century have been instrumental in hypothesizing curved visual spaces. Alleys were computed in perspective space and compared with reconstructed alleys of Blumenfeld. Parallel alleys were accurately described by perspective geometry. Accurate distance alleys were derived from parallel alleys by adjusting the interstimulus distances according to the size-distance invariance hypothesis. Agreement between computed and experimental alleys and accommodation of experimental results that rejected Luneburg’s model show that perspective space is an appropriate model for how we perceive orientations and angles. The model is also appropriate for perceived distance ratios between stimuli but fails to predict perceived distances. PMID:27648222

  13. Triumph or Triage? The World Food Problem in Geographical Perspective. Resource Paper No. 75-3.

    ERIC Educational Resources Information Center

    Knight, C. Gregory; Wilcox, R. Paul

    Emphasizing a problem-solving perspective, the document investigates the world food scene. Simply defined, the world food problem is the apparent inability of the world's people to feed themselves adequately and consistently. Intended for use by college level geography instructors as they develop courses on human uses of the environment, the…

  14. Facilitating Flexible Problem Solving: A Cognitive Load Perspective

    ERIC Educational Resources Information Center

    Kalyuga, Slava; Renkl, Alexander; Paas, Fred

    2010-01-01

    The development of flexible, transferable problem-solving skills is an important aim of contemporary educational systems. Since processing limitations of our mind represent a major factor influencing any meaningful learning, the acquisition of flexible problem-solving skills needs to be based on known characteristics of our cognitive architecture…

  15. Externalizing Behavior Problems during Adolescence: An Ecological Perspective

    ERIC Educational Resources Information Center

    White, Rachel; Renk, Kimberly

    2012-01-01

    Given the ramifications of difficulties related to externalizing behavior problems, the present study examined the relationships among adolescents' externalizing behavior problems, characteristics of adolescents' families, their perceived neighborhood support, and their acculturation. As part of this study, a culturally diverse sample of…

  16. Problem-Based Learning: A Critical Rationalist Perspective

    ERIC Educational Resources Information Center

    Parton, Graham; Bailey, Richard

    2008-01-01

    Although problem-based learning is being adopted by many institutions around the world as an effective model of learning in higher education, there is a surprising lack of critique in the problem-based learning literature in relation to its philosophical characteristics. This paper explores epistemology as a starting point for investigating the…

  17. Youth Education and Unemployment Problems. An International Perspective.

    ERIC Educational Resources Information Center

    Gordon, Margaret S.; Trow, Martin

    Essays focusing on issues concerning youth education and unemployment problems are presented in this document. It is divided into three general areas. The first, Youth Unemployment in Western Industrial Countries, reviews general dimensions of the problem, the cyclical hypothesis, the demand hypothesis, the supply hypothesis, disaggregating…

  18. Problems and Opportunities in School Financial Management: A Consultant's Perspective.

    ERIC Educational Resources Information Center

    Chabotar, Kent John

    1987-01-01

    Summarizes major problems in school financial management and suggests practical improvements to aid external reporting of financial data and internal management. Sections of the article describe these categories of problems: (1) budget presentation; (2) management control; (3) cost accounting; and (4) financial reporting. (PS)

  19. Early school adjustment problems: some perspectives and a project report.

    PubMed

    Adelman, H S; Taylor, L

    1991-07-01

    A kindergarten and elementary school intervention program for dealing with early school adjustment problems is described. It is designed to accommodate greater individual differences in classrooms, improve and augment regular support, and provide specialized staff development and interventions. Initial findings are presented, and the evolution of the program so as to address problems of school newcomers is discussed.

  20. Acoustic-structure interaction problems. Final report

    SciTech Connect

    Love, E.; Taylor, R.L.

    1993-12-01

    The purpose of this report is to compare and evaluate different numerical methods for solving problems of interaction between elastic solids and acoustic fluids. In particular, we concentrate our efforts on solution techniques involving the finite element method. To that end, in Chapter 2 we discuss different options for analysis of infinite fluids. In particular, the method of mesh trunction and the use of radiation elements and the use of infinite elements are discussed. Also discussed is the analysis of scattering from rigid boundaries. Chapter 3 is a brief discussion of finite element formulations for elastic solids. We review the development, of two dimensional plane strain elements and one dimensional plate and shell elements. In Chapter 4, there is a discussion of the method used to couple the solid and the fluid. We give examples for solution of scattering of pressure waves from thin elastic shell structures. Chapter 5 is a brief conclusion of results and includes recommendations for the best methods of solution and additional research.

  1. Effects of Exposure to Microwaves: Problems and Perspectives*

    PubMed Central

    Michaelson, Sol M.

    1974-01-01

    During the last 25 years, there has been a remarkable development and increase in the number of processes and devices that utilize or emit microwaves. Such devices are used in all sectors of our society for military, industrial, telecommunications, and consumer applications. Although there is information on biologic effects and potential hazard to man from exposure to microwaves, considerable confusion and misinformation has permeated not only the public press but also some scientific and technical publications. The purpose of this review is to place the available information on biologic effects of microwaves in proper perspective and to suggest approaches to future studies. PMID:4620329

  2. Bringing a Bayesian Perspective to Large Dimensional Problems in Geophysics

    NASA Astrophysics Data System (ADS)

    Duputel, Z.; Simons, M.; Jolivet, R.; Zaroli, C.; Rivera, L. A.; Ampuero, J. P.; Gombert, B.; Minson, S. E.

    2015-12-01

    The last decade has seen a substantial expansion of geophysical observations. Exploiting this wealth of data involves large ill-conditioned inverse problems requiring large numbers of uncertain parameters. A common approach in geophysics is to use some form of regularization that transforms the inversion into a well-conditioned optimization problem. While this approach is convenient and computationally inexpensive, the inherent non-uniqueness of our problems suggest that we should not simply search for a single optimal model, but rather attempt to describe the ensemble of plausible models that can fit the data and are consistent with prior information. This talk will present various applications of full Bayesian analysis techniques to large ill-posed inverse problems in geophysics. Despite significant computational cost, Bayesian sampling is a powerful tool to combine prior information, theoretical knowledge and data in order to address scientific problems probabilistically. We shall illustrate this by showing recent results for two types of problems: (1) the study of earthquakes sources and (2) imaging of the Earth interior. In particular, we will present different strategies that can be employed in order to achieve realistic uncertainty estimates.

  3. Characteristics of Problems for Problem-Based Learning: The Students' Perspective

    ERIC Educational Resources Information Center

    Sockalingam, Nachamma; Schmidt, Henk G.

    2011-01-01

    This study aimed to identify salient problem characteristics perceived by students in problem-based curricula. To this end, reflective essays from biomedical students (N = 34) on characteristics of good problems were text-analyzed. Students identified eleven characteristics, of which they found the extent to which the problem leads to desired…

  4. [Preimplantation Genetic Diagnosis by Blastocentesis: Problems and Perspectives].

    PubMed

    Zhigalina, D I; Skryabin, N A; Artyukhova, V G; Svetlakov, A V; Lebedev, I N

    2016-01-01

    The discovery of cell-free DNA in blastocoele fluid opens new perspectives for the development of preimplantation genetic diagnosis of human chromosomal and genetic diseases. In this review we analyzed the results of the first studies, which made it possible to evaluate the effectiveness of the application of a new source of biological material and showed a high degree of agreement between the results of molecular karyotyping with cell-free DNA and blastocyst cells. The results suggest the possibility of developing a noninvasive method of preimplantation genetic diagnosis, which may open a new round of progress in the field of assisted reproductive technologies and the genetics of early stages of human ontogenesis.

  5. How Problem Solving Can Develop an Algebraic Perspective of Mathematics

    ERIC Educational Resources Information Center

    Windsor, Will

    2011-01-01

    SProblem solving has a long and successful history in mathematics education and is valued by many teachers as a way to engage and facilitate learning within their classrooms. The potential benefit for using problem solving in the development of algebraic thinking is that "it may broaden and develop students' mathematical thinking beyond the…

  6. Accumulation of Welfare Problems in a Longitudinal Perspective

    ERIC Educational Resources Information Center

    Hallerod, Bjorn; Bask, Miia

    2008-01-01

    The central aim of the present paper is to analyse the degree to which welfare problems accumulate over time and to what extent such an accumulation is related to class position and household formation. We utilize longitudinal data from the Swedish Survey of Living Conditions, following a panel that was first interviewed in 1979 and, thereafter,…

  7. Adolescent Health Problems: Behavioral Perspectives. Advances in Pediatric Psychology.

    ERIC Educational Resources Information Center

    Wallander, Jan L., Ed.; Siegel, Lawrence J., Ed.

    This book examines the relationship between adolescent risk-taking behaviors and health. The health-related problems of adolescents frequently are manifestations of social, economic, or behavioral factors. Following an overview (Siegal), the chapters in the first section of the book explore general and conceptual issues: (1) "Epidemiology of…

  8. A Systemic Perspective of Solving Problems in the School.

    ERIC Educational Resources Information Center

    Molnar, Alex

    1986-01-01

    This article outlines the basic concepts in systemic therapy, including the nature of systemic behavior, the "punctuation" of behavior, the value of seeing behavior as "cooperative" rather than "resistant," and the concept of exception. Specific strategies school administrators and teachers can use when handling problem behavior are presented,…

  9. A Historical Perspective on Problems in Botany Teaching.

    ERIC Educational Resources Information Center

    Hershey, David R.

    1996-01-01

    Discusses how the many problems in botany teaching are interrelated and most have existed since at least the early 1900s. Considers botany teaching at both the precollege and introductory college levels. Discusses botany neglect in biology teaching, botanical illiteracy, uninteresting or irrelevant botany teaching, zoochauvinism, research…

  10. A Neuropsychological Perspective on Attention Problems in Neurofibromatosis Type 1

    ERIC Educational Resources Information Center

    Templer, Alexandra K.; Titus, Jeffrey B.; Gutmann, David H.

    2013-01-01

    Cognitive problems are common in children with neurofibromatosis type 1 and they can often complicate treatment. The current literature review examines cognitive functioning in neurofibromatosis type 1, with a specific focus on executive functioning. This includes exploration of how deficits in executive functioning are expressed in children with…

  11. Protein aggregate spreading in neurodegenerative diseases: Problems and perspectives

    PubMed Central

    Lee, Seung-Jae; Lim, Hee-Sun; Masliah, Eliezer; Lee, He-Jin

    2014-01-01

    Progressive accumulation of specific protein aggregates is a defining feature of many major neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, fronto-temporal dementia, Huntington’s disease, and Creutzfeldt–Jakob disease (CJD). Findings from several recent studies have suggested that aggregation-prone proteins, such as tau, α-synuclein, polyglutamine-containing proteins, and amyloid-β, can spread to other cells and brain regions, a phenomenon considered unique to prion disorders, such as CJD and bovine spongiform encephalopathy. Cell-to-cell propagation of protein aggregates may be the general underlying principle for progressive deterioration of neurodegenerative diseases. This may also have significant implications in cell replacement therapies, as evidenced by the propagation of α-synuclein aggregates from host to grafted cells in long-term transplants in Parkinson’s patients. Here, we review recent progress in protein aggregate propagation in experimental model systems and discuss outstanding questions and future perspectives. Understanding the mechanisms of this pathological spreading may open the way to unique opportunities for development of diagnostic techniques and novel therapies for protein misfolding-associated neurodegenerative diseases. PMID:21624403

  12. Perspective on Microfluidic Cell Separation: A Solved Problem?

    PubMed Central

    2015-01-01

    The purification and sorting of cells using microfluidic methodologies has been a remarkably active area of research over the past decade. Much of the scientific and technological work associated with microfluidic cell separation has been driven by needs in clinical diagnostics and therapeutic monitoring, most notably in the context of circulating tumor cells. The last several years have seen advances in a broad range of separation modalities ranging from miniaturized analogs of established techniques such as fluorescence- and magnetic-activated cell sorting (FACS and MACS, respectively), to more specialized approaches based on affinity, dielectrophoretic mobility, and inertial properties of cells. With several of these technologies nearing commercialization, there is a sense that the field of microfluidic cell separation has achieved a high level of maturity over an unusually short span of time. In this Perspective, we set the stage by describing major scientific and technological advances in this field and ask what the future holds. While many scientific questions remain unanswered and new compelling questions will undoubtedly arise, the relative maturity of this field poses some unique challenges. PMID:25350696

  13. Searching for hard instances of CVP problem-cryptographic perspective

    NASA Astrophysics Data System (ADS)

    Pardyak, Jacek

    2008-01-01

    Lattice is regular arrangement of points in R n. The Closest Vector Problem (CVP) is defined as follow: given a point y in Rn and a lattice basis B find lattice vector Bx closest to y . The CVP problem is believed to be computationally intractable in average. Here we propose a new way to generate hard instances of CVP and a method that allows us to construct a cryptographic trapdoor function based on it. We start with brief introduction to lattices. Next we present a very natural application of lattices in cryptography, i.e. GGH cryptosystem and the way the system was broken. Finally we present our modifications way to generate hard instances of CVP, harder than previously proposed in GGH.

  14. Problem Behaviors of Homeless Youth: A Social Capital Perspective

    PubMed Central

    Bantchevska, Denitza; Bartle-Haring, Suzanne; Dashora, Pushpanjali; Glebova, Tatiana; Slesnick, Natasha

    2008-01-01

    Homeless youth are one of the most marginalized groups in our society. Many researchers identify much higher levels of various problem behaviors among these youth compared to their non-homeless peers. The current study examined the utility of social capital in predicting problem behaviors among homeless youth. Overall, the theoretically derived social capital variable significantly predicted substance use frequency, sexual risk behavior, depression, delinquent behavior as well as number of days homeless. Thus, social capital was useful in understanding and predicting the current life situation among these youth and may be worthy of further study. Findings suggest that meaningful change should utilize interventions that go beyond the individual and are geared towards modifying the social context of individuals’ lives. PMID:18787647

  15. [Nursing care in practice: problems, perspectives, and need for systematization].

    PubMed

    de Andrade, Joseilze Santos; Vieira, Maria Jésia

    2005-01-01

    Descriptive and qualitative study carried out to subsidize the implementation process of Nursing systematization in a University Hospital. It was used questionnaires approaching activities, perception on Nursing and customer, knowledge and application of the Nursing process and problems which are consequence of non systemized assistance. Results identified that the nurses activities are based on the technique and on the service administration; that nursing was related to the help of the human beings' basic needs and holism, being the customer defined as the one that needs care; that the majority of nurses knew, in theory, the Nursing process, but did not apply it in practice. The most mentioned problems which were consequence of the non systemized assistance were the following: the quality assistance detriment, the service disorganization and the conflict of roles.

  16. Managing problem wildlife in the 'Old World': a veterinary perspective.

    PubMed

    Artois, M

    1997-01-01

    This paper focuses on mammalian pest species mainly in Europe and Africa and on implications for animal health, human safety, wildlife management and animal welfare. Three examples of problem species are presented: the wild boar (Sus scrofa), the stray dog (Canis familiaris) and the red fox, (Vulpes vulpes). Several species are reservoirs or vectors of transmissible diseases of man and of economically valuable domestic species. The control of these and other infections and the limitation of the nuisance or damage caused by these pest species involves lethal or non-lethal methods which are briefly reviewed. Some control measures require veterinary expertise, and veterinary involvement in managing problem species is likely to increase. With regard to fertility control, methods are considered which will allow an appropriate choice of the best technique for the management of problem animals in various habitats. For desirable native species, traditional methods of control, especially hunting in the case of game species, is preferable to contraception. For exotic or feral species, control of fertility seems to be a worthwhile option.

  17. State of psychiatry in Serbia--problems, advances and perspectives.

    PubMed

    Tosevski, Dusica Lecic; Gajic, Saveta Draganic; Milovancevic, Milica Pejovic

    2012-08-01

    Serbia has been exposed to many severe stressors during the last 20 years and as a result there is an increase of the incidence of mental health problems in its population, so that mental disorders are the second largest public health problem, after cardiovascular diseases. The National Strategy for Development of Mental Health Care was approved by the government in January 2007 which initiated the reform of psychiatry in the country. The major advantages of the existing organization of mental healthcare are a sufficient number of psychiatric services and the number of well educated professionals, but there are considerable problems in big psychiatric hospitals which are significantly overcrowded with patients, as well as with the lack of a network of community services. In the future, key points of mental health reform aim to focus on improved cooperation and collaboration between primary, secondary and tertiary healthcare levels, definition of catchment areas and responsibilities, continuing education of general practitioners in mental health issues, and better cooperation between psychiatric and social welfare institutions. The profile of the Institute for Mental Health is described as a case of good practice in the field of mental healthcare in Serbia.

  18. Image definition evaluation functions for X-ray crystallography: a new perspective on the phase problem.

    PubMed

    Li, Hui; He, Meng; Zhang, Ze

    2015-09-01

    The core theme of X-ray crystallography is reconstructing the electron-density distribution of crystals under the constraints of observed diffraction data. Nevertheless, reconstruction of the electron-density distribution by straightforward Fourier synthesis is usually hindered due to the well known phase problem and the finite resolution of diffraction data. In analogy with optical imaging systems, the reconstructed electron-density map may be regarded as the image of the real electron-density distribution in crystals. Inspired by image definition evaluation functions applied in the auto-focusing process, two evaluation functions are proposed for the reconstructed electron-density images. One of them is based on the atomicity of the electron-density distribution and properties of Fourier synthesis. Tests were performed on synthetic data of known structures, and it was found that this evaluation function can distinguish the correctly reconstructed electron-density image from wrong ones when diffraction data of atomic resolution are available. An algorithm was established based on this evaluation function and applied in reconstructing the electron-density image from the synthetic data of known structures. The other evaluation function, which is based on the positivity of electron density and constrained power spectrum entropy maximization, was designed for cases where only diffraction data of rather limited resolution are available. Tests on the synthetic data indicate that this evaluation function may identify the correct phase set even for a data set with resolution as low as 3.5 Å. Though no algorithm for structure solution has been figured out based on the latter function, the results presented here provide a new perspective on the phase problem. PMID:26317195

  19. PREFACE: Open Problems in Nuclear Structure Theory: Introduction Open Problems in Nuclear Structure Theory: Introduction

    NASA Astrophysics Data System (ADS)

    Dobaczewski, Jacek

    2010-06-01

    Nuclear structure theory is a domain of physics faced at present with great challenges and opportunities. A larger and larger body of high-precision experimental data has been and continues to be accumulated. Experiments on very exotic short-lived isotopes are the backbone of activity at numerous large-scale facilities. Over the years, tremendous progress has been made in understanding the basic features of nuclei. However, the theoretical description of nuclear systems is still far from being complete and is often not very precise. Many questions, both basic and practical, remain unanswered. The goal of publishing this special focus issue of Journal of Physics G: Nuclear and Particle Physics on Open Problems in Nuclear Structure Theory (OPeNST) is to construct a fundamental inventory thereof, so that the tasks and available options become more clearly exposed and that this will help to stimulate a boost in theoretical activity, commensurate with the experimental progress. The requested format and scope of the articles on OPeNST was quite flexible. The journal simply offered the possibility to provide a forum for the material, which is very often discussed at conferences during the coffee breaks but does not normally have sufficient substance to form regular publications. Nonetheless, very often formulating a problem provides a major step towards its solution, and it may constitute a scientific achievement on its own. Prospective authors were therefore invited to find their own balance between the two extremes of very general problems on the one hand (for example, to solve exactly the many-body equations for a hundred particles) and very specific problems on the other hand (for example, those that one could put in one's own grant proposal). The authors were also asked not to cover results already obtained, nor to limit their presentations to giving a review of the subject, although some elements of those could be included to properly introduce the subject matter

  20. Discovering the structure of mathematical problem solving.

    PubMed

    Anderson, John R; Lee, Hee Seung; Fincham, Jon M

    2014-08-15

    The goal of this research is to discover the stages of mathematical problem solving, the factors that influence the duration of these stages, and how these stages are related to the learning of a new mathematical competence. Using a combination of multivariate pattern analysis (MVPA) and hidden Markov models (HMM), we found that participants went through 5 major phases in solving a class of problems: A Define Phase where they identified the problem to be solved, an Encode Phase where they encoded the needed information, a Compute Phase where they performed the necessary arithmetic calculations, a Transform Phase where they performed any mathematical transformations, and a Respond Phase where they entered an answer. The Define Phase is characterized by activity in visual attention and default network regions, the Encode Phase by activity in visual regions, the Compute Phase by activity in regions active in mathematical tasks, the Transform Phase by activity in mathematical and response regions, and the Respond phase by activity in motor regions. The duration of the Compute and Transform Phases were the only ones that varied with condition. Two features distinguished the mastery trials on which participants came to understand a new problem type. First, the duration of late phases of the problem solution increased. Second, there was increased activation in the rostrolateral prefrontal cortex (RLPFC) and angular gyrus (AG), regions associated with metacognition. This indicates the importance of reflection to successful learning. PMID:24746954

  1. Discovering the structure of mathematical problem solving.

    PubMed

    Anderson, John R; Lee, Hee Seung; Fincham, Jon M

    2014-08-15

    The goal of this research is to discover the stages of mathematical problem solving, the factors that influence the duration of these stages, and how these stages are related to the learning of a new mathematical competence. Using a combination of multivariate pattern analysis (MVPA) and hidden Markov models (HMM), we found that participants went through 5 major phases in solving a class of problems: A Define Phase where they identified the problem to be solved, an Encode Phase where they encoded the needed information, a Compute Phase where they performed the necessary arithmetic calculations, a Transform Phase where they performed any mathematical transformations, and a Respond Phase where they entered an answer. The Define Phase is characterized by activity in visual attention and default network regions, the Encode Phase by activity in visual regions, the Compute Phase by activity in regions active in mathematical tasks, the Transform Phase by activity in mathematical and response regions, and the Respond phase by activity in motor regions. The duration of the Compute and Transform Phases were the only ones that varied with condition. Two features distinguished the mastery trials on which participants came to understand a new problem type. First, the duration of late phases of the problem solution increased. Second, there was increased activation in the rostrolateral prefrontal cortex (RLPFC) and angular gyrus (AG), regions associated with metacognition. This indicates the importance of reflection to successful learning.

  2. Bioinformatics education dissemination with an evolutionary problem solving perspective.

    PubMed

    Jungck, John R; Donovan, Samuel S; Weisstein, Anton E; Khiripet, Noppadon; Everse, Stephen J

    2010-11-01

    Bioinformatics is central to biology education in the 21st century. With the generation of terabytes of data per day, the application of computer-based tools to stored and distributed data is fundamentally changing research and its application to problems in medicine, agriculture, conservation and forensics. In light of this 'information revolution,' undergraduate biology curricula must be redesigned to prepare the next generation of informed citizens as well as those who will pursue careers in the life sciences. The BEDROCK initiative (Bioinformatics Education Dissemination: Reaching Out, Connecting and Knitting together) has fostered an international community of bioinformatics educators. The initiative's goals are to: (i) Identify and support faculty who can take leadership roles in bioinformatics education; (ii) Highlight and distribute innovative approaches to incorporating evolutionary bioinformatics data and techniques throughout undergraduate education; (iii) Establish mechanisms for the broad dissemination of bioinformatics resource materials and teaching models; (iv) Emphasize phylogenetic thinking and problem solving; and (v) Develop and publish new software tools to help students develop and test evolutionary hypotheses. Since 2002, BEDROCK has offered more than 50 faculty workshops around the world, published many resources and supported an environment for developing and sharing bioinformatics education approaches. The BEDROCK initiative builds on the established pedagogical philosophy and academic community of the BioQUEST Curriculum Consortium to assemble the diverse intellectual and human resources required to sustain an international reform effort in undergraduate bioinformatics education. PMID:21036947

  3. On some structure-turbulence interaction problems

    NASA Technical Reports Server (NTRS)

    Maekawa, S.; Lin, Y. K.

    1976-01-01

    The interactions between a turbulent flow structure; responding to its excitation were studied. The turbulence was typical of those associated with a boundary layer, having a cross-spectral density indicative of convection and statistical decay. A number of structural models were considered. Among the one-dimensional models were an unsupported infinite beam and a periodically supported infinite beam. The fuselage construction of an aircraft was then considered. For the two-dimensional case a simple membrane was used to illustrate the type of formulation applicable to most two-dimensional structures. Both the one-dimensional and two-dimensional structures studied were backed by a cavity filled with an initially quiescent fluid to simulate the acoustic environment when the structure forms one side of a cabin of a sea vessel or aircraft.

  4. Structured Collaboration versus Individual Learning in Solving Physics Problems

    NASA Astrophysics Data System (ADS)

    Harskamp, Egbert; Ding, Ning

    2006-11-01

    The research issue in this study is how to structure collaborative learning so that it improves solving physics problems more than individual learning. Structured collaborative learning has been compared with individual learning environments with Schoenfeld’s problem-solving episodes. Students took a pre-test and a post-test and had the opportunity to solve six physics problems. Ninety-nine students from a secondary school in Shanghai participated in the study. Students who learnt to solve problems in collaboration and students who learnt to solve problems individually with hints improved their problem-solving skills compared with those who learnt to solve the problems individually without hints. However, it was hard to discern an extra effect for students working collaboratively with hints—although we observed these students working in a more structured way than those in the other groups. We discuss ways to further investigate effective collaborative processes for solving physics problems.

  5. Unsolved problems and future perspectives of hepatitis B virus vaccination

    PubMed Central

    Tajiri, Kazuto; Shimizu, Yukihiro

    2015-01-01

    Hepatitis B virus (HBV) infection is still a serious worldwide problem, and vaccination is the most effective strategy for primary prevention of the infection. Although universal vaccination may be required for total eradication, several countries, including Japan, have not yet adopted universal vaccination programs. Some individuals are non-responders to HBV vaccine and several mechanisms responsible for their poor response have been proposed. To overcome non-response, third generation vaccines with pre-S proteins have been developed. These vaccines have shown better anti-HBs responses and may also be effective in preventing infection by HBV with S mutant. Improvement of vaccine efficacy by intradermal administration, or co-administration with cytokines or adjuvants, may also be effective in non-responders. The necessity, timing and method of booster vaccination in responders with decreased anti-HBs responses, and effective vaccination against S-mutant HBV, are issues requiring resolution in the global prevention of HBV infection. PMID:26109794

  6. Unsolved problems and future perspectives of hepatitis B virus vaccination.

    PubMed

    Tajiri, Kazuto; Shimizu, Yukihiro

    2015-06-21

    Hepatitis B virus (HBV) infection is still a serious worldwide problem, and vaccination is the most effective strategy for primary prevention of the infection. Although universal vaccination may be required for total eradication, several countries, including Japan, have not yet adopted universal vaccination programs. Some individuals are non-responders to HBV vaccine and several mechanisms responsible for their poor response have been proposed. To overcome non-response, third generation vaccines with pre-S proteins have been developed. These vaccines have shown better anti-HBs responses and may also be effective in preventing infection by HBV with S mutant. Improvement of vaccine efficacy by intradermal administration, or co-administration with cytokines or adjuvants, may also be effective in non-responders. The necessity, timing and method of booster vaccination in responders with decreased anti-HBs responses, and effective vaccination against S-mutant HBV, are issues requiring resolution in the global prevention of HBV infection.

  7. Surgical approach to fragility fractures: problems and perspectives.

    PubMed

    Tarantino, Umberto; Cannata, Giuseppe; Cerocchi, Irene; Lecce, Domenico; Iundusi, Riccardo; Celi, Monica

    2007-08-01

    The frequency of osteoporosis is constantly increasing all over the world. This pathology generates several problems, mostly due to fragility fractures, the worst consequence of impaired bone quality. Osteoporotic fractures often cause disability and loss of independence, partly because fracture fixation is not always easy and durable. So orthopedic surgeons need to learn and use new techniques to improve bone healing and surgical outcome, in order to grant fragility fracture patients a good quality of life. There are nails, screws and plates designed to maximize the bone-implant interface, substances which can be used locally to stimulate bone formation, and systemic therapies which can be used as adjuvants to decrease bone loss and/or enhance bone formation. Here, we report our personal experience, describing our surgical patients and their response to a bone-forming agent, such as teriparatide.

  8. Inclusion Strategies for Students with Learning and Behavior Problems: Perspectives, Experiences, and Best Practices.

    ERIC Educational Resources Information Center

    Zionts, Paul, Ed.

    This book presents discussions of the practical implementation of inclusion principles with students having learning and/or behavioral problems and disorders. The chapters, arranged under two topical units, "Perspectives and Experiences" and "Best Practices" are: (1) "Inclusion: Chasing the Impossible Dream? Maybe" (Paul Zionts); (2) "Responsible…

  9. Using Ontological Engineering to Overcome AI-ED Problems: Contribution, Impact and Perspectives

    ERIC Educational Resources Information Center

    Mizoguchi, Riichiro; Bourdeau, Jacqueline

    2016-01-01

    This article reflects on the ontology engineering methodology discussed by the paper entitled "Using Ontological Engineering to Overcome AI-ED Problems" published in this journal in 2000. We discuss the achievements obtained in the last 10 years, the impact of our work as well as recent trends and perspectives in ontology engineering for…

  10. International Perspectives on Problem-Based Learning: Contexts, Cultures, Challenges, and Adaptations

    ERIC Educational Resources Information Center

    Hmelo-Silver, Cindy E.

    2012-01-01

    The theme of this special issue is timely as the world becomes increasingly flat and globally connected (Friedman, 2007). By focusing on an international perspective in problem-based learning (PBL), it puts culture squarely in the center, whether it is a national or disciplinary culture. The articles in this special issue represent Thailand, South…

  11. Learner Perspectives of Online Problem-Based Learning and Applications from Cognitive Load Theory

    ERIC Educational Resources Information Center

    Chen, Ruth

    2016-01-01

    Problem-based learning (PBL) courses have historically been situated in physical classrooms involving in-person interactions. As online learning is embraced in higher education, programs that use PBL can integrate online platforms to support curriculum delivery and facilitate student engagement. This report describes student perspectives of the…

  12. The Problems of "Competence" and Alternatives from the Scandinavian Perspective of "Bildung"

    ERIC Educational Resources Information Center

    Willbergh, Ilmi

    2015-01-01

    The paper aims to show how competence as an educational concept for the 21st century is struggling with theoretical problems for which the concept of "Bildung" in the European tradition can offer alternatives, and to discuss the possibility of developing a sustainable educational concept from the perspectives of competence and…

  13. The cosmological 7Li problem from a nuclear physics perspective

    NASA Astrophysics Data System (ADS)

    Broggini, C.; Canton, L.; Fiorentini, G.; Villante, F. L.

    2012-06-01

    The primordial abundance of 7Li as predicted by Big Bang Nucleosynthesis (BBN) is more than a factor 2 larger than what has been observed in metal-poor halo stars. Herein, we analyze the possibility that this discrepancy originates from incorrect assumptions about the nuclear reaction cross sections relevant for BBN. To do this, we introduce an efficient method to calculate the changes in the 7Li abundance produced by arbitrary (temperature dependent) modifications of the nuclear reaction rates. Then, considering that 7Li is mainly produced from 7Be via the electron capture process 7Be+e- → 7Li+νe, we assess the impact of the various channels of 7Be destruction. Differently from previous analysis, we consider the role of unknown resonances by using a complete formalism which takes into account the effect of Coulomb and centrifugal barrier penetration and that does not rely on the use of the narrow-resonance approximation. As a result of this, the possibility of a nuclear physics solution to the 7Li problem is significantly suppressed. Given the present experimental and theoretical constraints, it is unlikely that the 7Be+n destruction rate is underestimated by the 2.5 factor required to solve the problem. We exclude, moreover, that resonant destruction in the channels 7Be+t and 7Be+3He can explain the 7Li puzzle. New unknown resonances in 7Be+d and 7Be+α could potentially produce significant effects. Recent experimental results have ruled out such a possibility for 7Be+d. On the other hand, for the 7Be+α channel very favorable conditions are required. The possible existence of a partially suitable resonant level in 11C is studied in the framework of a coupled-channel model and the possibility of a direct measurement is considered.

  14. Problem-Based Learning: Using Ill-Structured Problems in Biology Project Work

    ERIC Educational Resources Information Center

    Chin, Christine; Chia, Li-Gek

    2006-01-01

    This case study involved year 9 students carrying out project work in biology via problem-based learning. The purpose of the study was to (a) find out how students approach and work through ill-structured problems, (b) identify some issues and challenges related to the use of such problems, and (c) offer some practical suggestions on the…

  15. Current perspectives on RNA secondary structure probing.

    PubMed

    Kenyon, Julia; Prestwood, Liam; Lever, Andrew

    2014-08-01

    The range of roles played by structured RNAs in biological systems is vast. At the same time as we are learning more about the importance of RNA structure, recent advances in reagents, methods and technology mean that RNA secondary structural probing has become faster and more accurate. As a result, the capabilities of laboratories that already perform this type of structural analysis have increased greatly, and it has also become more widely accessible. The present review summarizes established and recently developed techniques. The information we can derive from secondary structural analysis is assessed, together with the areas in which we are likely to see exciting developments in the near future. PMID:25110033

  16. [Health system in Afghanistan: problems and institutional perspectives].

    PubMed

    Lejars, M

    2008-10-01

    Afghanistan has been ravaged by years of conflict. To provide emergency services and restore access health services, the Public Health Ministry with the assistance of partners developed first a package of basic health services delivered by NGO contractors and second a package of essential hospital services. The Ministry's role consists of providing guidance. To reduce the many issues and problems affecting this role, reforms are now being undertaken and a new national health care strategy is being developed within the framework of the National Development Strategy. An institution-building project has been initiated with European Union funding to allow the Health Ministry to carry out its stewardship and management functions with greater effectiveness and transparency. This project is essential for the successful outcome of all future strategies and programs planned by the Health Ministry to enhance its institutional effectiveness. The objectives of this project are to strengthen planning and auditing activities, promote quality assurance, implement funding mechanisms for health-related activities, organize management of human resources, maintain ongoing efforts to reform the administration and fight against corruption, and lay the foundations for managing finances and procurement. The scope of this project underlines the importance of its outcome. However the institution-building process will be long and constantly threatened by political instability and insecurity.

  17. The mine--body problem in an evolutionary perspective.

    PubMed

    Bunge, M

    1979-01-01

    Charles Darwin realized that his theory of evolution, jointly with the psychoneural identity hypothesis, implies the conjecture that behaviour and ideation evolve alongside anatomical and physiological traits. He was therefore the founder of evolutionary psychology. However, this science has not been pursued with vigour: not even its name has attained currency. In fact most psychologists still think in a pre-evolutionary fashion and seldom ask questions about the adaptive value and possible evolution of behavioural and mental traits. One reason for the underdevelopment of evolutionary psychology is that, on the whole, psychology is still separate from biology. In turn, one reason for this estrangement between close relatives is that psychology is still to some extent in the grip of psychoneural dualism, or the prehistoric belief that mind and body are separate entities. This doctrine is bound to block the advance of evolutionary psychology because a dualist must either deny mental evolution or speculate that it proceeds by some mechanism other than genic variation and natural (and social) selection. On the other hand the psychoneural identity hypothesis fits in with biology and, in particular, with evolutionary biology. Moreover, by construing ideation as a brain process, psychoneural monism explains how ideas (via behaviour) can become a motor of evolution as well as an outcome of it. So, it is in the interest of evolutionary psychologists to pay closer attention to the mind-body problem and to adopt the psychoneural identity hypothesis and turn it into a full-fledged scientific theory.

  18. Interlocked Problem Posing and Children's Problem Posing Performance in Free Structured Situations

    ERIC Educational Resources Information Center

    Cankoy, Osman

    2014-01-01

    The aim of this study is to explore the mathematical problem posing performance of students in free structured situations. Two classes of fifth grade students (N = 30) were randomly assigned to experimental and control groups. The categories of the problems posed in free structured situations by the 2 groups of students were studied through…

  19. Local structure of equality constrained NLP problems

    SciTech Connect

    Mari, J.

    1994-12-31

    We show that locally around a feasible point, the behavior of an equality constrained nonlinear program is described by the gradient and the Hessian of the Lagrangian on the tangent subspace. In particular this holds true for reduced gradient approaches. Applying the same ideas to the control of nonlinear ODE:s, one can device first and second order methods that can be applied also to stiff problems. We finally describe an application of these ideas to the optimization of the production of human growth factor by fed-batch fermentation.

  20. Interface Problems: Structural Constraints on Interpretation?

    ERIC Educational Resources Information Center

    Frazier, Lyn; Clifton, Charles; Rayner, Keith; Deevy, Patricia; Koh, Sungryong; Bader, Markus

    2005-01-01

    Five experiments investigated the interpretation of quantified noun phrases in relation to discourse structure. They demonstrated, using questionnaire and on-line reading techniques, that readers in English prefer to give a quantified noun phrase in (VP-external) subject position a presuppositional interpretation, in which the noun phrase limits…

  1. An electronic structure perspective of graphene interfaces

    NASA Astrophysics Data System (ADS)

    Schultz, Brian J.; Dennis, Robert V.; Lee, Vincent; Banerjee, Sarbajit

    2014-03-01

    The unusual electronic structure of graphene characterized by linear energy dispersion of bands adjacent to the Fermi level underpins its remarkable transport properties. However, for practical device integration, graphene will need to be interfaced with other materials: 2D layered structures, metals (as ad-atoms, nanoparticles, extended surfaces, and patterned metamaterial geometries), dielectrics, organics, or hybrid structures that in turn are constituted from various inorganic or organic components. The structural complexity at these nanoscale interfaces holds much promise for manifestation of novel emergent phenomena and provides a means to modulate the electronic structure of graphene. In this feature article, we review the modifications to the electronic structure of graphene induced upon interfacing with disparate types of materials with an emphasis on iterative learnings from theoretical calculations and electronic spectroscopy (X-ray absorption fine structure (XAFS) spectroscopy, scanning transmission X-ray microscopy (STXM), angle-resolved photoemission spectroscopy (ARPES), and X-ray magnetic circular dichroism (XMCD)). We discuss approaches for engineering and modulating a bandgap in graphene through interfacial hybridization, outline experimental methods for examining electronic structure at interfaces, and overview device implications of engineered interfaces. A unified view of how geometric and electronic structure are correlated at interfaces will provide a rational means for designing heterostructures exhibiting emergent physical phenomena with implications for plasmonics, photonics, spintronics, and engineered polymer and metal matrix composites.

  2. An electronic structure perspective of graphene interfaces.

    PubMed

    Schultz, Brian J; Dennis, Robert V; Lee, Vincent; Banerjee, Sarbajit

    2014-04-01

    The unusual electronic structure of graphene characterized by linear energy dispersion of bands adjacent to the Fermi level underpins its remarkable transport properties. However, for practical device integration, graphene will need to be interfaced with other materials: 2D layered structures, metals (as ad-atoms, nanoparticles, extended surfaces, and patterned metamaterial geometries), dielectrics, organics, or hybrid structures that in turn are constituted from various inorganic or organic components. The structural complexity at these nanoscale interfaces holds much promise for manifestation of novel emergent phenomena and provides a means to modulate the electronic structure of graphene. In this feature article, we review the modifications to the electronic structure of graphene induced upon interfacing with disparate types of materials with an emphasis on iterative learnings from theoretical calculations and electronic spectroscopy (X-ray absorption fine structure (XAFS) spectroscopy, scanning transmission X-ray microscopy (STXM), angle-resolved photoemission spectroscopy (ARPES), and X-ray magnetic circular dichroism (XMCD)). We discuss approaches for engineering and modulating a bandgap in graphene through interfacial hybridization, outline experimental methods for examining electronic structure at interfaces, and overview device implications of engineered interfaces. A unified view of how geometric and electronic structure are correlated at interfaces will provide a rational means for designing heterostructures exhibiting emergent physical phenomena with implications for plasmonics, photonics, spintronics, and engineered polymer and metal matrix composites.

  3. RNA structure in splicing: An evolutionary perspective.

    PubMed

    Lin, Chien-Ling; Taggart, Allison J; Fairbrother, William G

    2016-09-01

    Pre-mRNA splicing is a key post-transcriptional regulation process in which introns are excised and exons are ligated together. A novel class of structured intron was recently discovered in fish. Simple expansions of complementary AC and GT dimers at opposite boundaries of an intron were found to form a bridging structure, thereby enforcing correct splice site pairing across the intron. In some fish introns, the RNA structures are strong enough to bypass the need of regulatory protein factors for splicing. Here, we discuss the prevalence and potential functions of highly structured introns. In humans, structured introns usually arise through the co-occurrence of C and G-rich repeats at intron boundaries. We explore the potentially instructive example of the HLA receptor genes. In HLA pre-mRNA, structured introns flank the exons that encode the highly polymorphic β sheet cleft, making the processing of the transcript robust to variants that disrupt splicing factor binding. While selective forces that have shaped HLA receptor are fairly atypical, numerous other highly polymorphic genes that encode receptors contain structured introns. Finally, we discuss how the elevated mutation rate associated with the simple repeats that often compose structured intron can make structured introns themselves rapidly evolving elements. PMID:27454491

  4. Perspectives on communication problems in the English-speaking Caribbean.

    PubMed

    Okwesa, B A

    1984-03-01

    The Caribbean is experiencing a host of serious socioeconomic problems that prevent the majority of the population from realizing and maintaining a satisfactory standard of living. Food and Nutrition Surveys of some countries identified a lack of information on health, food, and nutrition as a primary reason for the prevalence of malnutrition, infectious diseases, and nutrition related diseases. "Misinformation" creates an often insurmountable barrier to effective communication between source and receiver, in this case the health, food, and nutrition sector and the wider community. Misinformation occurs when the message is either incorrect, incomplete, inconsistent with other messages in the same program, or contradictory. This element of "misinformation" can negate the effectiveness of the message and an entire communication program. Some examples are cited which show that in programs aimed at effecting change in attitude or behavior it is essential to ensure that messages are clearly communicated to avoid misunderstanding and the right infrastructure is in place for the innovation proposed by the message to be carried out. In the Jamaica Nutrition Education Program (JNEP) were used to communicate the messages. Evaluation revealed that health staff were providing incorrect and contradictory advice about breastfeeding, which showed that they lacked basic information on the subject. In Barbados, despite an intensified health education campaign, face to face instruction in the clinics, and extensive use of the Caribbean Food and Nutrition Institute (CFNI) Breastfeeding Package as well as other locally developed materials, a marked decline in breastfeeding was recorded over the 1969-81 survey period. Misinformation and misunderstanding among mothers were identified as the key reasons for the failure of breastfeeding. In relation to the decline in breaastfeeding and incorrect weaning practices, mass media was implicated as luring mothers away from natural feeding

  5. Perspective view. Fivestory reinforced concrete factory building reveals the structural ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Perspective view. Five-story reinforced concrete factory building reveals the structural frame on the exterior of the facade. Twelve bay facade facing onto Clay Avenue (north facade) has first floor openings bricked up. Mix of typical factory windows and glass block windows fill the majority of the openings on the rest of building - Russell Industrial Center, 1600 Clay Avenue, Detroit, MI

  6. Solving Fluid Structure Interaction Problems with an Immersed Boundary Method

    NASA Technical Reports Server (NTRS)

    Barad, Michael F.; Brehm, Christoph; Kiris, Cetin C.

    2016-01-01

    An immersed boundary method for the compressible Navier-Stokes equations can be used for moving boundary problems as well as fully coupled fluid-structure interaction is presented. The underlying Cartesian immersed boundary method of the Launch Ascent and Vehicle Aerodynamics (LAVA) framework, based on the locally stabilized immersed boundary method previously presented by the authors, is extended to account for unsteady boundary motion and coupled to linear and geometrically nonlinear structural finite element solvers. The approach is validated for moving boundary problems with prescribed body motion and fully coupled fluid structure interaction problems. Keywords: Immersed Boundary Method, Higher-Order Finite Difference Method, Fluid Structure Interaction.

  7. A Topological Perspective of Neural Network Structure

    NASA Astrophysics Data System (ADS)

    Sizemore, Ann; Giusti, Chad; Cieslak, Matthew; Grafton, Scott; Bassett, Danielle

    The wiring patterns of white matter tracts between brain regions inform functional capabilities of the neural network. Indeed, densely connected and cyclically arranged cognitive systems may communicate and thus perform distinctly. However, previously employed graph theoretical statistics are local in nature and thus insensitive to such global structure. Here we present an investigation of the structural neural network in eight healthy individuals using persistent homology. An extension of homology to weighted networks, persistent homology records both circuits and cliques (all-to-all connected subgraphs) through a repetitive thresholding process, thus perceiving structural motifs. We report structural features found across patients and discuss brain regions responsible for these patterns, finally considering the implications of such motifs in relation to cognitive function.

  8. Arylamine N-acetyltransferases: a structural perspective

    PubMed Central

    Zhou, Xiaotong; Ma, Zhiguo; Dong, Dong; Wu, Baojian

    2013-01-01

    Arylamine N-acetyltransferase (NAT) plays an important role in metabolism and detoxification of many compounds including drugs and environmental carcinogens through chemical modification of the amine group with an acetyl group. Recent studies have suggested that NATs are also involved in cancer cell growth and inhibition of the enzymes may be a potential target for cancer chemotherapy. Three-dimensional (3D) structures are available for NATs from both prokaryotes and eukaryotes. These structures provide valuable insights into the acetylation mechanism, features of the active site and the structural determinants that govern substrate/inhibitor-binding specificity. Such insights allow a more precise understanding of the structure–activity relationships for NAT substrates and inhibitors. Furthermore, the structural elucidation of NATs has generated powerful tools in the design of small molecule inhibitors that should alleviate cancer, based on the important role of the enzyme in cancer biology. PMID:23517104

  9. New Perspectives on Structured Life Education Groups.

    ERIC Educational Resources Information Center

    Apgar, Kathryn; Coplon, Jennifer Kane

    1985-01-01

    Defines life education groups as educational, time-limited groups focusing on family and personal growth issues. Discusses the conceptual framework of the groups, the value of structure, prevention and intervention, and responding to the needs of diverse groups. (JAC)

  10. Structural dynamics technology research in NASA: Perspective on future needs

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The perspective of a NASA ad hoc study group on future research needs in structural dynamics within the aerospace industry is presented. The common aspects of the design process across the industry are identified and the role of structural dynamics is established through a discussion of various design considerations having their basis in structural dynamics. The specific structural dynamics issues involved are identified and assessed as to their current technological status and trends. Projections of future requirements based on this assessment are made and areas of research to meet them are identified.

  11. What makes a problem an ethical problem? An empirical perspective on the nature of ethical problems in general practice

    PubMed Central

    Braunack-Mayer, A. J.

    2001-01-01

    Whilst there has been considerable debate about the fit between moral theory and moral reasoning in everyday life, the way in which moral problems are defined has rarely been questioned. This paper presents a qualitative analysis of interviews conducted with 15 general practitioners (GPs) in South Australia to argue that the way in which the bioethics literature defines an ethical dilemma captures only some of the range of lay views about the nature of ethical problems. The bioethics literature has defined ethical dilemmas in terms of conflict and choice between values, beliefs and options for action. While some of the views of some of the GPs in this study about the nature of their ethical dilemmas certainly accorded with this definition, other explanations of the ethical nature of their problems revolved around the publicity associated with the issues they were discussing, concern about their relationships with patients, and anxiety about threats to their integrity and reputation. The variety of views about what makes a problem a moral problem indicates that the moral domain is perhaps wider and richer than mainstream bioethics would generally allow. Key Words: Empirical ethics • general practice • qualitative research PMID:11314166

  12. Cosmological structure problem of the ekpyrotic scenario

    NASA Astrophysics Data System (ADS)

    Hwang, Jai-Chan

    2002-03-01

    We address the perturbation power spectrum generated in the recently proposed ekpyrotic scenario by Khoury et al. The issue has been raised recently by Lyth who used the conventional method based on a conserved variable in the large-scale limit, and derived different results from Khoury et al. The calculation is straightforward in the uniform-curvature gauge where the generated blue spectrum with a suppressed amplitude survives as the final spectrum. Whereas, although the metric fluctuations become unimportant and a scale-invariant spectrum is generated in the zero-shear gauge, the mode does not survive the bounce, but has the same final result. Therefore, an exponential potential leads to a power-law expansion or contraction a~\\|t\\|p, and the power p dictates the final power spectra of both the scalar and tensor structures. If p<<1 as one realization of the ekpyrotic scenario suggests, the results are nS-1~=2~=nT and the amplitude of the scalar perturbation is suppressed relative to that of the gravitational wave by a factor (p)/2. Both results confirm Lyth's. An observation is made on the constraint on the dynamics of the seed generating stage from the requirement of a scale-invariant spectrum.

  13. Interface problems: structural constraints on interpretation?

    PubMed

    Frazier, Lyn; Clifton, Charles; Rayner, Keith; Deevy, Patricia; Koh, Sungryong; Bader, Markus

    2005-05-01

    Five experiments investigated the interpretation of quantified noun phrases in relation to discourse structure. They demonstrated, using questionnaire and on-line reading techniques, that readers in English prefer to give a quantified noun phrase in (VP-external) subject position a presuppositional interpretation, in which the noun phrase limits or restricts the interpretation of an already available set, rather than giving it a nonpresuppositional or existential interpretation, in which it introduces completely new entities into the discourse. Experiment 1 showed that readers prefer a presuppositional interpretation of three ships over the existential interpretation in Five ships appeared on the horizon. Three ships sank. Experiment 2 showed longer reading times in sentences that are disambiguated toward the existential interpretation than in sentences that permit the presuppositional interpretation. Experiment 3 suggested that the presuppositional preference is greater when the phrase three ships occurs outside the verb phrase than when it occurs inside the verb phrase. Experiment 4 showed that Korean subjects marked with a topic marker received more presuppositional interpretations than subjects marked with a nominative marker. Experiment 5 showed that German subjects in VP-external (but nontopic) position received more presuppositional interpretations than VP-internal subjects. The results suggest the syntactic position of a phrase is one determinant of its interpretation, as expected according to the mapping hypothesis of Diesing (1992).

  14. A VLSI structure for the deadlock avoidance problem

    SciTech Connect

    Bertolazzi, P.; Bongiovanni, G.

    1985-11-01

    In this paper the authors present two VLSI structures implementing the banker's algorithm for the deadlock avoidance problem, and we derive the area x (time)/sup 2/ lower bound for such an algorithm. The first structure is based on the VLSI mesh of trees. The second structure is a modification of the first one, and it approaches more closely the theoretical lower bound.

  15. New perspectives on the Popigai impact structure

    NASA Technical Reports Server (NTRS)

    Garvin, J. B.; Deino, A. L.

    1992-01-01

    The record of large-scale cratering on Earth is scant, and the only currently 'proven' 100-km-class impact structure known to have formed within the Cenozoic is Popigai, located in the Siberian Arctic at 71.5 deg N, 111 deg E. Popigai is clearly a multiringed impact basin formed within the crystalline shield rocks (Anabar) and platform sediments of the Siberian taiga, and estimates of the volume of preserved impact melt typically exceed 1700 cu km, which is within a factor of 2-3 of what would be predicted using scaling relationships. We present the preliminary results of an analysis of the present-day topography of the Popigai structure, together with refined absolute age estimates, in order to reconstruct the pre-erosional morphology of the basin, as well as to quantify the erosion or sediment infill rates in the Popigai region.

  16. Sphingosine-1-phosphate metabolism: A structural perspective.

    PubMed

    Pulkoski-Gross, Michael J; Donaldson, Jane C; Obeid, Lina M

    2015-01-01

    Sphingolipids represent an important class of bioactive signaling lipids which have key roles in numerous cellular processes. Over the last few decades, the levels of bioactive sphingolipids and/or their metabolizing enzymes have been realized to be important factors involved in disease development and progression, most notably in cancer. Targeting sphingolipid-metabolizing enzymes in disease states has been the focus of many studies and has resulted in a number of pharmacological inhibitors, with some making it into the clinic as therapeutics. In order to better understand the regulation of sphingolipid-metabolizing enzymes as well as to develop much more potent and specific inhibitors, the field of sphingolipids has recently taken a turn toward structural biology. The last decade has seen the structural determination of a number of sphingolipid enzymes and effector proteins. In these terms, one of the most complete arms of the sphingolipid pathway is the sphingosine-1-phosphate (S1P) arm. The structures of proteins involved in the function and regulation of S1P are being used to investigate further the regulation of said proteins as well as in the design and development of inhibitors as potential therapeutics.

  17. Human sulfatases: a structural perspective to catalysis.

    PubMed

    Ghosh, D

    2007-08-01

    The sulfatase family of enzymes catalyzes hydrolysis of sulfate ester bonds of a wide variety of substrates. Seventeen genes have been identified in this class of sulfatases, many of which are associated with genetic disorders leading to reduction or loss of function of the corresponding enzymes. Amino acid sequence homology suggests that the enzymes have similar overall folds, mechanisms of action, and bivalent metal ion-binding sites. A catalytic cysteine residue, strictly conserved in prokaryotic and eukaryotic sulfatases, is post-translationally modified into a formylglycine. Hydroxylation of the formylglycine residue by a water molecule forming the activated hydroxylformylglycine (a formylglycine hydrate or a gem-diol) is a necessary step for the enzyme's sulfatase activity. Crystal structures of three human sulfatases, arylsulfatases A and B(ARSA and ARSB), and estrone/dehydroepiandrosterone sulfatase or steroid sulfatase (STS), also known as arylsulfatase C, have been determined. While ARSA and ARSB are water-soluble enzymes, STS has a hydrophobic domain and is an integral membrane protein of the endoplasmic reticulum. In this article, we compare and contrast sulfatase structures and revisit the proposed catalytic mechanism in light of available structural and functional data. Examination of the STS active site reveals substrate-specific interactions previously identified as the estrogen-recognition motif. Because of the proximity of the catalytic cleft of STS to the membrane surface, the lipid bilayer has a critical role in the constitution of the active site, unlike other sulfatases.

  18. Structural qualia: a solution to the hard problem of consciousness

    PubMed Central

    Loorits, Kristjan

    2014-01-01

    The hard problem of consciousness has been often claimed to be unsolvable by the methods of traditional empirical sciences. It has been argued that all the objects of empirical sciences can be fully analyzed in structural terms but that consciousness is (or has) something over and above its structure. However, modern neuroscience has introduced a theoretical framework in which also the apparently non-structural aspects of consciousness, namely the so called qualia or qualitative properties, can be analyzed in structural terms. That framework allows us to see qualia as something compositional with internal structures that fully determine their qualitative nature. Moreover, those internal structures can be identified which certain neural patterns. Thus consciousness as a whole can be seen as a complex neural pattern that misperceives some of its own highly complex structural properties as monadic and qualitative. Such neural pattern is analyzable in fully structural terms and thereby the hard problem is solved. PMID:24672510

  19. "Opportunities in Work Clothes": Online Problem-Solving Project Structures.

    ERIC Educational Resources Information Center

    Harris, Judi

    1994-01-01

    Provides activity structures for and gives examples of problem-solving projects to be used with educational telecomputing. Highlights include information searches, electronic process writing, sequential creations, parallel problem solving, simulations, social action projects, and instructions for accessing information about these and other…

  20. Recent advances in numerical analysis of structural eigenvalue problems

    NASA Technical Reports Server (NTRS)

    Gupta, K. K.

    1973-01-01

    A wide range of eigenvalue problems encountered in practical structural engineering analyses is defined, in which the structures are assumed to be discretized by any suitable technique such as the finite-element method. A review of the usual numerical procedures for the solution of such eigenvalue problems is presented and is followed by an extensive account of recently developed eigenproblem solution procedures. Particular emphasis is placed on the new numerical algorithms and associated computer programs based on the Sturm sequence method. Eigenvalue algorithms developed for efficient solution of natural frequency and buckling problems of structures are presented, as well as some eigenvalue procedures formulated in connection with the solution of quadratic matrix equations associated with free vibration analysis of structures. A new algorithm is described for natural frequency analysis of damped structural systems.

  1. Exploring Teacher and School Resilience as a New Perspective to Solve Persistent Problems in the Educational Sector

    ERIC Educational Resources Information Center

    Schelvis, Roosmarijn M. C.; Zwetsloot, Gerard I. J. M.; Bos, Evelien H.; Wiezer, Noortje M.

    2014-01-01

    In this paper, we will explore the relevance, meaning and perspectives of teacher, team and school resilience. The central research questions are: does the concept of teacher, team and school resilience offer new and promising perspectives on persistent problems in the educational sector? And secondly; how can resilience at individual, team and…

  2. The Lunar Internal Structure Model: Problems and Solutions

    NASA Astrophysics Data System (ADS)

    Nefedyev, Yuri; Gusev, Alexander; Petrova, Natalia; Varaksina, Natalia

    The report is devoted the problems of the internal structure and gravitational field of the Moon. New data received from 14 newest instruments installed on low-orbit satellite Kaguya essentially enriched our knowledge of the Moon. Chinese satellite ChagE-1 and Indian Сhandrayan-1 have demonstrated strong potential of China and India in the field of lunar research and obtained new data on gravitational field, mascons, crust, and geochemical composition of the circumlunar space. Internal structure of the Moon: There are some essential arguments in favor of existence of a small-sized Moon’s core made of metallic iron alloyed with a small amount of sulfur and/or oxygen, and availability of hot viscous lower mantle. Structure of gravitational field of the Moon, determined by the comparison of high-precision trajectory measurements by Lunar Prospector (1998- 1999) with the results of laser altimetry obtained by Clementine (1994), as well as with data sets of laser ranging of the Moon (1970-2006), assumes the presence of a metal core. Interpretation of the polar moment value within the framework of chemical, thermal and density models of lunar crust and mantle informed conclusions about the weight and size of the core. LLR analysis of dissipation of rotation of the Moon points at two possible sources of dissipation: monthly solid-state inflows and liquid core, rotation of which differs from viscous-elastic mantle. Liquid (melted) core has its unique impact on the Moon’s rotation. In particular, there are two force moments due to topographical and phase interaction at the boundary between liquid core and elastic mantle (CMB). Liquid core can rotate independently from solid mantle Selenoid satellites (SS) open new and most perspective opportunities in the study of gravitational field and the Moon’s figure. SSs “Moon 10”, “Apollo”, “Clementine”, “Lunar Prospector” trajectory tracking data processing has allowed for identification of coefficients in

  3. Supporting teachers who introduce curricular innovations into their classrooms: A problem-solving perspective

    NASA Astrophysics Data System (ADS)

    Yerushalmi, Edit; Eylon, Bat-Sheva

    2013-06-01

    When classroom teachers introduce curricular innovations that conflict with their former deeply rooted practices, the teachers themselves experience a process of change. One professional development framework intended to support this change is the customization workshop, in which teachers cooperatively customize innovations to their own classroom contexts, reflect on the strengths and weaknesses of classroom implementation, and refine their innovations. Two goals sometimes conflict in such workshops: developing teachers’ skills as reflective practitioners (process) and maintaining crucial characteristics of the original innovations (product). This paper explores how to meet both challenges using the insights from a perspective that provides a striking parallel: developing expertlike problem-solving skills (process) as well as conceptual understanding (product) in the physics classroom. We apply this perspective by (a) characterizing an expertlike approach to pedagogical problem solving in the context of customization workshops, (b) determining the nature of pedagogical problems best suited for developing such an expertlike approach, (c) suggesting how to design customization workshops that support teachers to develop an expertlike approach to pedagogical problem solving. In particular, we hypothesize that applying cognitive apprenticeship in customization workshops in a manner similar to its application in the teaching of expertlike problem solving in the physics classroom should effectively help teachers approach the pedagogical problem of customization in an expertlike manner. We support our hypothesis with an empirical study of three year-long cooperative customization workshops for physics teachers that differed in terms of mentoring approach. We examined the questions (a) under which mentoring approaches did teachers perform an expertlike pedagogical problem-solving process and (b) which practices and perceptions emerged through execution of this process?

  4. [Mental representation, psychic structure, and behaviour problems in preschool children].

    PubMed

    Juen, Florian; Benecke, Cord; von Wyl, Agnes; Schick, Andreas; Cierpka, Manfred

    2005-03-01

    Mental health problems in terms of deviant behaviour and emotional problems are assumed in context with mental representations and indicators of internal psychic structure. In distinction to adults there is little empirical research concerning this matter. On the basis of Childrens' Play Narratives (MacArthur Story Stem Battery) we collected data about content-themes, structural indicators and process criteria of 73 preschool children and implicated these information with behaviour ratings of parents and kindergarden teachers. Many correlations were found particularly with structural indicators, process criteria and behaviour ratings. The results are discussed both with respect to content and methodical aspects. PMID:15850165

  5. Algebraic multigrid methods applied to problems in computational structural mechanics

    NASA Technical Reports Server (NTRS)

    Mccormick, Steve; Ruge, John

    1989-01-01

    The development of algebraic multigrid (AMG) methods and their application to certain problems in structural mechanics are described with emphasis on two- and three-dimensional linear elasticity equations and the 'jacket problems' (three-dimensional beam structures). Various possible extensions of AMG are also described. The basic idea of AMG is to develop the discretization sequence based on the target matrix and not the differential equation. Therefore, the matrix is analyzed for certain dependencies that permit the proper construction of coarser matrices and attendant transfer operators. In this manner, AMG appears to be adaptable to structural analysis applications.

  6. Variational structure of inverse problems in wave propagation and vibration

    SciTech Connect

    Berryman, J.G.

    1995-03-01

    Practical algorithms for solving realistic inverse problems may often be viewed as problems in nonlinear programming with the data serving as constraints. Such problems are most easily analyzed when it is possible to segment the solution space into regions that are feasible (satisfying all the known constraints) and infeasible (violating some of the constraints). Then, if the feasible set is convex or at least compact, the solution to the problem will normally lie on the boundary of the feasible set. A nonlinear program may seek the solution by systematically exploring the boundary while satisfying progressively more constraints. Examples of inverse problems in wave propagation (traveltime tomography) and vibration (modal analysis) will be presented to illustrate how the variational structure of these problems may be used to create nonlinear programs using implicit variational constraints.

  7. Whither Ribosome Structure and Dynamics Research? (A Perspective).

    PubMed

    Frank, Joachim

    2016-09-11

    As high-resolution cryogenic electron microscopy (cryo-EM) structures of ribosomes proliferate, at resolutions that allow atomic interactions to be visualized, this article attempts to give a perspective on the way research on ribosome structure and dynamics may be headed, and particularly the new opportunities we have gained through recent advances in cryo-EM. It is pointed out that single-molecule FRET and cryo-EM form natural complements in the characterization of ribosome dynamics and transitions among equilibrating states of in vitro translational systems. PMID:27178840

  8. Mlpnp - a Real-Time Maximum Likelihood Solution to the Perspective-N Problem

    NASA Astrophysics Data System (ADS)

    Urban, S.; Leitloff, J.; Hinz, S.

    2016-06-01

    In this paper, a statistically optimal solution to the Perspective-n-Point (PnP) problem is presented. Many solutions to the PnP problem are geometrically optimal, but do not consider the uncertainties of the observations. In addition, it would be desirable to have an internal estimation of the accuracy of the estimated rotation and translation parameters of the camera pose. Thus, we propose a novel maximum likelihood solution to the PnP problem, that incorporates image observation uncertainties and remains real-time capable at the same time. Further, the presented method is general, as is works with 3D direction vectors instead of 2D image points and is thus able to cope with arbitrary central camera models. This is achieved by projecting (and thus reducing) the covariance matrices of the observations to the corresponding vector tangent space.

  9. RNA structure: merging chemistry and genomics for a holistic perspective.

    PubMed

    Kubota, Miles; Chan, Dalen; Spitale, Robert C

    2015-10-01

    The advent of deep sequencing technology has unexpectedly advanced our structural understanding of molecules composed of nucleic acids. A significant amount of progress has been made recently extrapolating the chemical methods to probe RNA structure into sequencing methods. Herein we review some of the canonical methods to analyze RNA structure, and then we outline how these have been used to probe the structure of many RNAs in parallel. The key is the transformation of structural biology problems into sequencing problems, whereby sequencing power can be interpreted to understand nucleic acid proximity, nucleic acid conformation, or nucleic acid-protein interactions. Utilizing such technologies in this way has the promise to provide novel structural insights into the mechanisms that control normal cellular physiology and provide insight into how structure could be perturbed in disease.

  10. Home care assistants’ perspectives on detecting mental health problems and promoting mental health among community-dwelling seniors with multimorbidity

    PubMed Central

    Grundberg, Åke; Hansson, Anna; Religa, Dorota; Hillerås, Pernilla

    2016-01-01

    Introduction Elderly people with multiple chronic conditions, or multimorbidity, are at risk of developing poor mental health. These seniors often remain in their homes with support from home care assistants (HCAs). Mental health promotion by HCAs needs to be studied further because they may be among the first to observe changes in clients’ mental health status. Aim To describe HCAs’ perspectives on detecting mental health problems and promoting mental health among homebound seniors with multimorbidity. Methods We applied a descriptive qualitative study design using semi-structured interviews. Content analyses were performed on five focus group interviews conducted in 2014 with 26 HCAs. Results Most HCAs stated that they were experienced in caring for clients with mental health problems such as anxiety, depression, sleep problems, and high alcohol consumption. The HCAs mentioned as causes, or risk factors, multiple chronic conditions, feelings of loneliness, and social isolation. The findings reveal that continuity of care and seniors’ own thoughts and perceptions were essential to detecting mental health problems. Observation, collaboration, and social support emerged as important means of detecting mental health problems and promoting mental health. Conclusion The HCAs had knowledge of risk factors, but they seemed insecure about which health professionals had the primary responsibility for mental health. They also seemed to have detected early signs of mental health problems, even though good personal knowledge of the client and continuity in home visits were crucial to do so. When it came to mental health promotion, the suggestions related to the aim of ending social isolation, decreasing feelings of loneliness, and increasing physical activity. The results indicate that the HCAs seemed dependent on supervision by district nurses and on care managers’ decisions to support the needed care, to schedule assignments related to the detection of mental health

  11. The damper placement problem for large flexible space structures

    NASA Technical Reports Server (NTRS)

    Kincaid, Rex K.

    1992-01-01

    The damper placement problem for large flexible space truss structures is formulated as a combinatorial optimization problem. The objective is to determine the p truss members of the structure to replace with active (or passive) dampers so that the modal damping ratio is as large as possible for all significant modes of vibration. Equivalently, given a strain energy matrix with rows indexed on the modes and the columns indexed on the truss members, we seek to find the set of p columns such that the smallest row sum, over the p columns, is maximized. We develop a tabu search heuristic for the damper placement problems on the Controls Structures Interaction (CSI) Phase 1 Evolutionary Model (10 modes and 1507 truss members). The resulting solutions are shown to be of high quality.

  12. Environmental Policies and Problems in Japan, China, and Hong Kong: Travel Perspectives.

    ERIC Educational Resources Information Center

    Therivel, Riki; Wrisberg, Mette

    1988-01-01

    Compared are some of the environmental planning policies and developmental policies of three regions of the Far East. Discusses the relationship between social structures and environmental problems such as pollution, erosion, waste disposal, and the uses of technology. (CW)

  13. Numerical methods on some structured matrix algebra problems

    SciTech Connect

    Jessup, E.R.

    1996-06-01

    This proposal concerned the design, analysis, and implementation of serial and parallel algorithms for certain structured matrix algebra problems. It emphasized large order problems and so focused on methods that can be implemented efficiently on distributed-memory MIMD multiprocessors. Such machines supply the computing power and extensive memory demanded by the large order problems. We proposed to examine three classes of matrix algebra problems: the symmetric and nonsymmetric eigenvalue problems (especially the tridiagonal cases) and the solution of linear systems with specially structured coefficient matrices. As all of these are of practical interest, a major goal of this work was to translate our research in linear algebra into useful tools for use by the computational scientists interested in these and related applications. Thus, in addition to software specific to the linear algebra problems, we proposed to produce a programming paradigm and library to aid in the design and implementation of programs for distributed-memory MIMD computers. We now report on our progress on each of the problems and on the programming tools.

  14. The Association between Sleep Problems and Psychotic Symptoms in the General Population: A Global Perspective

    PubMed Central

    Koyanagi, Ai; Stickley, Andrew

    2015-01-01

    Study Objectives: To assess the prevalence of sleep problems and their association with psychotic symptoms using a global database. Design: Community-based cross-sectional study. Setting: Data were analyzed from the World Health Organization's World Health Survey (WHS), a population-based survey conducted in 70 countries between 2002 and 2004. Patients or Participants: 261,547 individuals aged ≥ 18 years from 56 countries. Interventions: N/A. Measurements and Results: The presence of psychotic symptoms in the past 12 months was established using 4 questions pertaining to positive symptoms from the psychosis screening module of the Composite International Diagnostic Interview. Sleep problems referred to severe or extreme sleep problems in the past 30 days. Multivariable logistic regression was used to estimate the associations. The overall prevalence of sleep problems was 7.6% and ranged from 1.6% (China) to 18.6% (Morocco). Sleep problems were associated with significantly higher odds for at least one psychotic symptom in the vast majority of countries. In the pooled sample, after adjusting for demographic factors, alcohol consumption, smoking, and chronic medical conditions, having sleep problems resulted in an odds ratio (OR) for at least one psychotic symptom of 2.41 (95% confidence interval [CI] 2.18–2.65). This OR was 1.59 (1.40–1.81) when further adjusted for anxiety and depression. Conclusions: A strong association between sleep problems and psychotic symptoms was observed globally. These results have clinical implications and serve as a basis for future studies to elucidate the causal association between psychotic symptoms and sleep problems. Citation: Koyanagi A, Stickley A. The association between sleep problems and psychotic symptoms in the general population: a global perspective. SLEEP 2015;38(12):1875–1885. PMID:26085291

  15. A Qualitative Approach to a Better Understanding of the Problems Underlying Drug Shortages, as Viewed from Belgian, French and the European Union's Perspectives.

    PubMed

    Bogaert, Petronille; Bochenek, Tomasz; Prokop, Anna; Pilc, Andrzej

    2015-01-01

    The problem of drug shortages has been reported worldwide, gaining prominence in multiple domains and several countries in recent years. The aim of the study was to analyze, characterise and assess this problem in Belgium and France, while also adopting a wider perspective from the European Union. A qualitative methodological approach was employed, including semi-structured interviews with the representatives of respective national health authorities, pharmaceutical companies and wholesalers, as well as hospital and community pharmacists. The research was conducted in early 2014. Four themes, which were identified through the interviews, were addressed in the paper, i.e. a) defining drug shortages, b) their dynamics and perception, c) their determinants, d) the role of the European and national institutions in coping with the problem. Three groups of determinants of drug shortages were identified throughout this study: manufacturing problems, distribution and supply problems, and problems related to economic aspects. Currently, the Member States of the European Union are striving to resolve the problem very much on their own, although a far more focused and dedicated collaboration may well prove instrumental in coping with drug shortages throughout Europe more effectively. To the best of the authors' knowledge, this is the first qualitative study to investigate the characteristics, key determinants, and the problem drivers of drug shortages, focusing on this particular group of countries, while also adopting the European Union's perspective. PMID:25942432

  16. A Qualitative Approach to a Better Understanding of the Problems Underlying Drug Shortages, as Viewed from Belgian, French and the European Union’s Perspectives

    PubMed Central

    Prokop, Anna; Pilc, Andrzej

    2015-01-01

    The problem of drug shortages has been reported worldwide, gaining prominence in multiple domains and several countries in recent years. The aim of the study was to analyze, characterise and assess this problem in Belgium and France, while also adopting a wider perspective from the European Union. A qualitative methodological approach was employed, including semi-structured interviews with the representatives of respective national health authorities, pharmaceutical companies and wholesalers, as well as hospital and community pharmacists. The research was conducted in early 2014. Four themes, which were identified through the interviews, were addressed in the paper, i.e. a) defining drug shortages, b) their dynamics and perception, c) their determinants, d) the role of the European and national institutions in coping with the problem. Three groups of determinants of drug shortages were identified throughout this study: manufacturing problems, distribution and supply problems, and problems related to economic aspects. Currently, the Member States of the European Union are striving to resolve the problem very much on their own, although a far more focused and dedicated collaboration may well prove instrumental in coping with drug shortages throughout Europe more effectively. To the best of the authors’ knowledge, this is the first qualitative study to investigate the characteristics, key determinants, and the problem drivers of drug shortages, focusing on this particular group of countries, while also adopting the European Union’s perspective. PMID:25942432

  17. Promoting Issues-based STSE Perspectives in Science Teacher Education: Problems of Identity and Ideology

    NASA Astrophysics Data System (ADS)

    Pedretti, Erminia G.; Bencze, Larry; Hewitt, Jim; Romkey, Lisa; Jivraj, Ashifa

    2008-09-01

    Although science, technology, society and environment (STSE) education has gained considerable force in the past few years, it has made fewer strides in practice. We suggest that science teacher identity plays a role in the adoption of STSE perspectives. Simply put, issues-based STSE education challenges traditional images of a science teacher and science instructional ideologies. In this paper, we briefly describe the development of a multimedia documentary depicting issues-based STSE education in a teacher’s class and its subsequent implementation with 64 secondary student-teachers at a large Canadian university. Specifically, we set out to explore: (1) science teacher candidates’ responses to a case of issues-based STSE teaching, and (2) how science teacher identity intersects with the adoption of STSE perspectives. Findings reveal that although teacher candidates expressed confidence and motivation regarding teaching STSE, they also indicated decreased likelihood to teach these perspectives in their early years of teaching. Particular tensions or problems of practice consistently emerged that helped explain this paradox including issues related to: control and autonomy; support and belonging; expertise and negotiating curriculum; politicization and action; and biases and ideological bents. We conclude our paper with a discussion regarding the lessons learned about STSE education, teacher identity and the role of multimedia case methods.

  18. Teaching Mathematical Word Problem Solving: The Quality of Evidence for Strategy Instruction Priming the Problem Structure

    ERIC Educational Resources Information Center

    Jitendra, Asha K.; Petersen-Brown, Shawna; Lein, Amy E.; Zaslofsky, Anne F.; Kunkel, Amy K.; Jung, Pyung-Gang; Egan, Andrea M.

    2015-01-01

    This study examined the quality of the research base related to strategy instruction priming the underlying mathematical problem structure for students with learning disabilities and those at risk for mathematics difficulties. We evaluated the quality of methodological rigor of 18 group research studies using the criteria proposed by Gersten et…

  19. Can the Stark-Einstein law resolve the measurement problem from an animate perspective?

    PubMed

    Thaheld, Fred H

    2015-09-01

    Analysis of the Stark-Einstein law as it applies to the retinal molecule, which is part of the rhodopsin molecule within the rod cells of the retina, reveals that it may provide the solution to the measurement problem from an animate perspective. That it represents a natural boundary where the Schrödinger equation or wave function automatically goes from linear to nonlinear while remaining in a deterministic state. It will be possible in the near future to subject this theory to empirical tests as has been previously proposed. This analysis provides a contrast to the many decades well studied and debated inanimate measurement problem and would represent an addition to the Stark-Einstein law involving information carried by the photon.

  20. Cancer Biomarkers Discovery and Validation: State of the Art, Problems and Future Perspectives.

    PubMed

    Mordente, Alvaro; Meucci, Elisabetta; Martorana, Giuseppe Ettore; Silvestrini, Andrea

    2015-01-01

    Cancer is one of the major public health problems worldwide representing the leading cause of morbidity and mortality in industrialized countries. To reduce cancer morbidity and mortality as well as to facilitate the evolution from the traditional "one size fits all" strategy to a new "personalized" cancer therapy (i.e., the right drug to the right patient at the right time, using the right dose and schedule), there is an urgent need of reliable, robust, accurate and validated cancer biomarker tests.Unfortunately, despite the impressive advances in tumor biology research as well as in high-powerful "omics" technologies, the translation of candidate cancer biomarkers from bench to bedside is lengthy and challenging and only a few tumor marker tests have been adopted successfully into routine clinical care of oncologic patients.This chapter provides an updated background on biomarkers research in oncology, including biomarkers clinical uses, and discusses the problems of discovery pipeline, biomarkers failures and future perspectives.

  1. Time-Limited, Structured Youth Mentoring and Adolescent Problem Behaviors

    ERIC Educational Resources Information Center

    Weiler, Lindsey M.; Haddock, Shelley A.; Zimmerman, Toni S.; Henry, Kimberly L.; Krafchick, Jennifer L.; Youngblade, Lise M.

    2015-01-01

    Youth mentoring can have a profound impact on the lives of high-risk youth. This study presents the Campus Corps program, a time-limited (12-week), structured mentoring program for high-risk youth (ages 11--18), and results from a quasi-experimental pilot evaluation. Baseline and post-intervention problem behavior data from 315 offending youth…

  2. Detection of structural deterioration and associated airline maintenance problems

    NASA Technical Reports Server (NTRS)

    Henniker, H. D.; Mitchell, R. G.

    1972-01-01

    Airline operations involving the detection of structural deterioration and associated maintenance problems are discussed. The standard approach to the maintenance and inspection of aircraft components and systems is described. The frequency of inspections and the application of preventive maintenance practices are examined. The types of failure which airline transport aircraft encounter and the steps taken to prevent catastrophic failure are reported.

  3. PARTI primitives for unstructured and block structured problems

    NASA Technical Reports Server (NTRS)

    Sussman, Alan; Saltz, Joel; Das, Raja; Gupta, S.; Mavriplis, Dimitri; Ponnusamy, Ravi; Crowley, Kay

    1992-01-01

    Described here is a set of primitives (PARTI) developed to efficiently execute unstructured and block structured problems on distributed memory parallel machines. We present experimental data from a 3-D unstructured Euler solver run on the Intel Touchstone Delta to demonstrate the usefulness of our methods.

  4. Dynamic Programming for Structured Continuous Markov Decision Problems

    NASA Technical Reports Server (NTRS)

    Dearden, Richard; Meuleau, Nicholas; Washington, Richard; Feng, Zhengzhu

    2004-01-01

    We describe an approach for exploiting structure in Markov Decision Processes with continuous state variables. At each step of the dynamic programming, the state space is dynamically partitioned into regions where the value function is the same throughout the region. We first describe the algorithm for piecewise constant representations. We then extend it to piecewise linear representations, using techniques from POMDPs to represent and reason about linear surfaces efficiently. We show that for complex, structured problems, our approach exploits the natural structure so that optimal solutions can be computed efficiently.

  5. Quantum inferring acausal structures and the Monty Hall problem

    NASA Astrophysics Data System (ADS)

    Kurzyk, Dariusz; Glos, Adam

    2016-09-01

    This paper presents a quantum version of the Monty Hall problem based upon the quantum inferring acausal structures, which can be identified with generalization of Bayesian networks. Considered structures are expressed in formalism of quantum information theory, where density operators are identified with quantum generalization of probability distributions. Conditional relations between quantum counterpart of random variables are described by quantum conditional operators. Presented quantum inferring structures are used to construct a model inspired by scenario of well-known Monty Hall game, where we show the differences between classical and quantum Bayesian reasoning.

  6. Finite element solution of transient fluid-structure interaction problems

    NASA Technical Reports Server (NTRS)

    Everstine, Gordon C.; Cheng, Raymond S.; Hambric, Stephen A.

    1991-01-01

    A finite element approach using NASTRAN is developed for solving time-dependent fluid-structure interaction problems, with emphasis on the transient scattering of acoustic waves from submerged elastic structures. Finite elements are used for modeling both structure and fluid domains to facilitate the graphical display of the wave motion through both media. For the liquid, the use of velocity potential as the fundamental unknown results in a symmetric matrix equation. The approach is illustrated for the problem of transient scattering from a submerged elastic spherical shell subjected to an incident tone burst. The use of an analogy between the equations of elasticity and the wave equation of acoustics, a necessary ingredient to the procedure, is summarized.

  7. An Event-Based Solution to the Perspective-n-Point Problem.

    PubMed

    Reverter Valeiras, David; Kime, Sihem; Ieng, Sio-Hoi; Benosman, Ryad Benjamin

    2016-01-01

    The goal of the Perspective-n-Point problem (PnP) is to find the relative pose between an object and a camera from a set of n pairings between 3D points and their corresponding 2D projections on the focal plane. Current state of the art solutions, designed to operate on images, rely on computationally expensive minimization techniques. For the first time, this work introduces an event-based PnP algorithm designed to work on the output of a neuromorphic event-based vision sensor. The problem is formulated here as a least-squares minimization problem, where the error function is updated with every incoming event. The optimal translation is then computed in closed form, while the desired rotation is given by the evolution of a virtual mechanical system whose energy is proven to be equal to the error function. This allows for a simple yet robust solution of the problem, showing how event-based vision can simplify computer vision tasks. The approach takes full advantage of the high temporal resolution of the sensor, as the estimated pose is incrementally updated with every incoming event. Two approaches are proposed: the Full and the Efficient methods. These two methods are compared against a state of the art PnP algorithm both on synthetic and on real data, producing similar accuracy in addition of being faster. PMID:27242412

  8. An Event-Based Solution to the Perspective-n-Point Problem

    PubMed Central

    Reverter Valeiras, David; Kime, Sihem; Ieng, Sio-Hoi; Benosman, Ryad Benjamin

    2016-01-01

    The goal of the Perspective-n-Point problem (PnP) is to find the relative pose between an object and a camera from a set of n pairings between 3D points and their corresponding 2D projections on the focal plane. Current state of the art solutions, designed to operate on images, rely on computationally expensive minimization techniques. For the first time, this work introduces an event-based PnP algorithm designed to work on the output of a neuromorphic event-based vision sensor. The problem is formulated here as a least-squares minimization problem, where the error function is updated with every incoming event. The optimal translation is then computed in closed form, while the desired rotation is given by the evolution of a virtual mechanical system whose energy is proven to be equal to the error function. This allows for a simple yet robust solution of the problem, showing how event-based vision can simplify computer vision tasks. The approach takes full advantage of the high temporal resolution of the sensor, as the estimated pose is incrementally updated with every incoming event. Two approaches are proposed: the Full and the Efficient methods. These two methods are compared against a state of the art PnP algorithm both on synthetic and on real data, producing similar accuracy in addition of being faster. PMID:27242412

  9. Understanding congestion in China's medical market: an incentive structure perspective.

    PubMed

    Sun, Zesheng; Wang, Shuhong; Barnes, Stephen R

    2016-04-01

    Congestion has become one of the most important factors leading to patient dissatisfaction and doctor-patient conflicts in the medical market of China. In this study, we explore the causes and effects of structural congestion in the Chinese medical market from an incentive structure perspective. Our analysis reveals that prior medical system reforms with price regulation in China have induced hospitals to establish incentives for capital-intensive investments, while ignoring human capital, and have driven medical staff and patients to higher-level hospitals, reinforcing an incentive structure in which congestion in higher-level hospitals and idle resources in lower-level hospitals coexist. The existing incentive structure has led to cost increases and degradation of human capital and specific factor effects. Recent reforms to reduce congestion in the Chinese medical market were not effective. Most of them had no impact on and did not involve the existing distorted incentive structure. Future reforms should consider rebalancing expectations for medical quality, free flow of human capital and price regulation reforms to rebuild a new incentive structure. PMID:26185181

  10. Understanding congestion in China's medical market: an incentive structure perspective.

    PubMed

    Sun, Zesheng; Wang, Shuhong; Barnes, Stephen R

    2016-04-01

    Congestion has become one of the most important factors leading to patient dissatisfaction and doctor-patient conflicts in the medical market of China. In this study, we explore the causes and effects of structural congestion in the Chinese medical market from an incentive structure perspective. Our analysis reveals that prior medical system reforms with price regulation in China have induced hospitals to establish incentives for capital-intensive investments, while ignoring human capital, and have driven medical staff and patients to higher-level hospitals, reinforcing an incentive structure in which congestion in higher-level hospitals and idle resources in lower-level hospitals coexist. The existing incentive structure has led to cost increases and degradation of human capital and specific factor effects. Recent reforms to reduce congestion in the Chinese medical market were not effective. Most of them had no impact on and did not involve the existing distorted incentive structure. Future reforms should consider rebalancing expectations for medical quality, free flow of human capital and price regulation reforms to rebuild a new incentive structure.

  11. MSClique: Multiple Structure Discovery through the Maximum Weighted Clique Problem.

    PubMed

    Sanroma, Gerard; Penate-Sanchez, Adrian; Alquézar, René; Serratosa, Francesc; Moreno-Noguer, Francesc; Andrade-Cetto, Juan; González Ballester, Miguel Ángel

    2016-01-01

    We present a novel approach for feature correspondence and multiple structure discovery in computer vision. In contrast to existing methods, we exploit the fact that point-sets on the same structure usually lie close to each other, thus forming clusters in the image. Given a pair of input images, we initially extract points of interest and extract hierarchical representations by agglomerative clustering. We use the maximum weighted clique problem to find the set of corresponding clusters with maximum number of inliers representing the multiple structures at the correct scales. Our method is parameter-free and only needs two sets of points along with their tentative correspondences, thus being extremely easy to use. We demonstrate the effectiveness of our method in multiple-structure fitting experiments in both publicly available and in-house datasets. As shown in the experiments, our approach finds a higher number of structures containing fewer outliers compared to state-of-the-art methods. PMID:26766071

  12. MSClique: Multiple Structure Discovery through the Maximum Weighted Clique Problem.

    PubMed

    Sanroma, Gerard; Penate-Sanchez, Adrian; Alquézar, René; Serratosa, Francesc; Moreno-Noguer, Francesc; Andrade-Cetto, Juan; González Ballester, Miguel Ángel

    2016-01-01

    We present a novel approach for feature correspondence and multiple structure discovery in computer vision. In contrast to existing methods, we exploit the fact that point-sets on the same structure usually lie close to each other, thus forming clusters in the image. Given a pair of input images, we initially extract points of interest and extract hierarchical representations by agglomerative clustering. We use the maximum weighted clique problem to find the set of corresponding clusters with maximum number of inliers representing the multiple structures at the correct scales. Our method is parameter-free and only needs two sets of points along with their tentative correspondences, thus being extremely easy to use. We demonstrate the effectiveness of our method in multiple-structure fitting experiments in both publicly available and in-house datasets. As shown in the experiments, our approach finds a higher number of structures containing fewer outliers compared to state-of-the-art methods.

  13. MSClique: Multiple Structure Discovery through the Maximum Weighted Clique Problem

    PubMed Central

    Alquézar, René; Serratosa, Francesc; Moreno-Noguer, Francesc; Andrade-Cetto, Juan; González Ballester, Miguel Ángel

    2016-01-01

    We present a novel approach for feature correspondence and multiple structure discovery in computer vision. In contrast to existing methods, we exploit the fact that point-sets on the same structure usually lie close to each other, thus forming clusters in the image. Given a pair of input images, we initially extract points of interest and extract hierarchical representations by agglomerative clustering. We use the maximum weighted clique problem to find the set of corresponding clusters with maximum number of inliers representing the multiple structures at the correct scales. Our method is parameter-free and only needs two sets of points along with their tentative correspondences, thus being extremely easy to use. We demonstrate the effectiveness of our method in multiple-structure fitting experiments in both publicly available and in-house datasets. As shown in the experiments, our approach finds a higher number of structures containing fewer outliers compared to state-of-the-art methods. PMID:26766071

  14. Structural DNA Nanotechnology: State of the Art and Future Perspective

    PubMed Central

    2015-01-01

    Over the past three decades DNA has emerged as an exceptional molecular building block for nanoconstruction due to its predictable conformation and programmable intra- and intermolecular Watson–Crick base-pairing interactions. A variety of convenient design rules and reliable assembly methods have been developed to engineer DNA nanostructures of increasing complexity. The ability to create designer DNA architectures with accurate spatial control has allowed researchers to explore novel applications in many directions, such as directed material assembly, structural biology, biocatalysis, DNA computing, nanorobotics, disease diagnosis, and drug delivery. This Perspective discusses the state of the art in the field of structural DNA nanotechnology and presents some of the challenges and opportunities that exist in DNA-based molecular design and programming. PMID:25029570

  15. Structural DNA nanotechnology: state of the art and future perspective.

    PubMed

    Zhang, Fei; Nangreave, Jeanette; Liu, Yan; Yan, Hao

    2014-08-13

    Over the past three decades DNA has emerged as an exceptional molecular building block for nanoconstruction due to its predictable conformation and programmable intra- and intermolecular Watson-Crick base-pairing interactions. A variety of convenient design rules and reliable assembly methods have been developed to engineer DNA nanostructures of increasing complexity. The ability to create designer DNA architectures with accurate spatial control has allowed researchers to explore novel applications in many directions, such as directed material assembly, structural biology, biocatalysis, DNA computing, nanorobotics, disease diagnosis, and drug delivery. This Perspective discusses the state of the art in the field of structural DNA nanotechnology and presents some of the challenges and opportunities that exist in DNA-based molecular design and programming. PMID:25029570

  16. Mathematical theory of a relaxed design problem in structural optimization

    NASA Technical Reports Server (NTRS)

    Kikuchi, Noboru; Suzuki, Katsuyuki

    1990-01-01

    Various attempts have been made to construct a rigorous mathematical theory of optimization for size, shape, and topology (i.e. layout) of an elastic structure. If these are represented by a finite number of parametric functions, as Armand described, it is possible to construct an existence theory of the optimum design using compactness argument in a finite dimensional design space or a closed admissible set of a finite dimensional design space. However, if the admissible design set is a subset of non-reflexive Banach space such as L(sup infinity)(Omega), construction of the existence theory of the optimum design becomes suddenly difficult and requires to extend (i.e. generalize) the design problem to much more wider class of design that is compatible to mechanics of structures in the sense of variational principle. Starting from the study by Cheng and Olhoff, Lurie, Cherkaev, and Fedorov introduced a new concept of convergence of design variables in a generalized sense and construct the 'G-Closure' theory of an extended (relaxed) optimum design problem. A similar attempt, but independent in large extent, can also be found in Kohn and Strang in which the shape and topology optimization problem is relaxed to allow to use of perforated composites rather than restricting it to usual solid structures. An identical idea is also stated in Murat and Tartar using the notion of the homogenization theory. That is, introducing possibility of micro-scale perforation together with the theory of homogenization, the optimum design problem is relaxed to construct its mathematical theory. It is also noted that this type of relaxed design problem is perfectly matched to the variational principle in structural mechanics.

  17. Nonlinear Transient Problems Using Structure Compatible Heat Transfer Code

    NASA Technical Reports Server (NTRS)

    Hou, Gene

    2000-01-01

    The report documents the recent effort to enhance a transient linear heat transfer code so as to solve nonlinear problems. The linear heat transfer code was originally developed by Dr. Kim Bey of NASA Largely and called the Structure-Compatible Heat Transfer (SCHT) code. The report includes four parts. The first part outlines the formulation of the heat transfer problem of concern. The second and the third parts give detailed procedures to construct the nonlinear finite element equations and the required Jacobian matrices for the nonlinear iterative method, Newton-Raphson method. The final part summarizes the results of the numerical experiments on the newly enhanced SCHT code.

  18. Teaching mathematical word problem solving: the quality of evidence for strategy instruction priming the problem structure.

    PubMed

    Jitendra, Asha K; Petersen-Brown, Shawna; Lein, Amy E; Zaslofsky, Anne F; Kunkel, Amy K; Jung, Pyung-Gang; Egan, Andrea M

    2015-01-01

    This study examined the quality of the research base related to strategy instruction priming the underlying mathematical problem structure for students with learning disabilities and those at risk for mathematics difficulties. We evaluated the quality of methodological rigor of 18 group research studies using the criteria proposed by Gersten et al. and 10 single case design (SCD) research studies using criteria suggested by Horner et al. and the What Works Clearinghouse. Results indicated that 14 group design studies met the criteria for high-quality or acceptable research, whereas SCD studies did not meet the standards for an evidence-based practice. Based on these findings, strategy instruction priming the mathematics problem structure is considered an evidence-based practice using only group design methodological criteria. Implications for future research and for practice are discussed.

  19. Some problems of ultrasonic and laser cutting of biological structures

    NASA Astrophysics Data System (ADS)

    Gudra, T.; Muc, S.

    2008-02-01

    The paper presents the influence of the laser and ultrasonic cutter on biological structures and some problems bound up with the applications of lasers and ultrasounds in surgery. The advantages and disadvantages of contact and noncontact applications of the Nd:YAG laser were presented as well as the usefulness of the ultrasonic cutter for selective cutting of various tissues. The benefits resulting from a combination of the two technologies were discussed, and initial tests of the laser-ultrasonic cutter operation were performed, pointing to the possibility of improving the cutting of biological structures.

  20. Quantum N-body problem: Matrix structures and equations

    NASA Astrophysics Data System (ADS)

    Yakovlev, S. L.

    2014-10-01

    We consider matrix structures in the quantum N-body problem that generalize the Faddeev components for resolvents, T-matrices, and eigenfunctions of the continuous spectrum. We write matrix equations for the introduced components of T-matrices and resolvents and use these equations to obtain matrix operators generalizing the matrix three-particle Faddeev operators to the case of arbitrarily many particles. We determine the eigenfunctions of the continuous spectrum of these matrix operators.

  1. Potential structural material problems in a hydrogen energy system

    NASA Technical Reports Server (NTRS)

    Gray, H. R.; Nelson, H. G.; Johnson, R. E.; Mcpherson, W. B.; Howard, F. S.; Swisher, J. H.

    1976-01-01

    Potential structural material problems that may be encountered in the three components of a hydrogen energy system - production, transmission/storage, and utilization - have been identified. Hydrogen embrittlement, corrosion, oxidation, and erosion may occur during the production of hydrogen. Hydrogen embrittlement is of major concern during both transmission and utilization of hydrogen. Specific materials research and development programs necessary to support a hydrogen energy system are described. An awareness of probable shortages of strategic materials has been maintained in these suggested programs.

  2. Potential structural material problems in a hydrogen energy system

    NASA Technical Reports Server (NTRS)

    Gray, H. R.; Nelson, H. G.; Johnson, R. E.; Mcpherson, B.; Howard, F. S.; Swisher, J. H.

    1975-01-01

    Potential structural material problems that may be encountered in the three components of a hydrogen energy system - production, transmission/storage, and utilization - were identified. Hydrogen embrittlement, corrosion, oxidation, and erosion may occur during the production of hydrogen. Hydrogen embrittlement is of major concern during both transmission and utilization of hydrogen. Specific materials research and development programs necessary to support a hydrogen energy system are described.

  3. Applying simulation modeling to problems in toxicology and risk assessment--a short perspective.

    PubMed

    Andersen, M E; Clewell, H J; Frederick, C B

    1995-08-01

    The goals of this perspective have been to examine areas where quantitative simulation models may be useful in toxicology and related risk assessment fields and to offer suggestions for preparing manuscripts that describe these models. If developments in other disciplines serve as a bell-wether, the use of mathematical models in toxicology will continue to increase, partly, at least, because the new generations of scientists are being trained in an electronic environment where computation of all kinds is learned at an early age. Undoubtedly, however, the utility of these models will be directly tied to the skills of investigators in accurately describing models in their research papers. These publications should convey descriptions of both the insights obtained and the opportunities provided by these models to integrate existing data bases and suggest new and useful experiments. We hope these comments serve to facilitate the expansion of good modeling practices as applied to toxicological problems.

  4. [Between idealization and devaluation--problems and perspectives of theoretical analyses of female homo- and heterosexuality].

    PubMed

    Flaake, K

    1995-01-01

    Female homosexuality remains a controversial topic. Comparing psychoanalytic and sociological-feminist approaches to the phenomenon, the author points up clear theoretical distinctions between the two perspectives. Feminist authors tend towards an idealization of female homosexuality, while psychoanalysts display an inclination to devalue it as something pathological. However, the latent messages in both discourses have a number of points in common, traceable to a key problem they both have to come to grips with, the "lesbian complex". In lesbian relationships Flaake discerns a "third chance", an area not sanctioned by society, in which it is possible to re-attempt something left unattained in the early mother-daughter relationship: the appropriation of the female body. PMID:7480810

  5. A structural and functional perspective of alphavirus replication and assembly

    PubMed Central

    Jose, Joyce; Snyder, Jonathan E; Kuhn, Richard J

    2009-01-01

    Alphaviruses are small, spherical, enveloped, positive-sense ssRNA viruses responsible for a considerable number of human and animal diseases. Alphavirus members include Chikungunya virus, Sindbis virus, Semliki Forest virus, the western, eastern and Venezuelan equine encephalitis viruses, and the Ross River virus. Alphaviruses can cause arthritic diseases and encephalitis in humans and animals and continue to be a worldwide threat. The viruses are transmitted by blood-sucking arthropods, and replicate in both arthropod and vertebrate hosts. Alphaviruses form spherical particles (65–70 nm in diameter) with icosahedral symmetry and a triangulation number of four. The icosahedral structures of alphaviruses have been defined to very high resolutions by cryo-electron microscopy and crystallographic studies. In this review, we summarize the major events in alphavirus infection: entry, replication, assembly and budding. We focus on data acquired from structural and functional studies of the alphaviruses. These structural and functional data provide a broader perspective of the virus lifecycle and structure, and allow additional insight into these important viruses. PMID:19722838

  6. Caring for children with learning disabilities who present problem behaviours: a maternal perspective.

    PubMed

    Johnson, Robert F; O'Reilly, Michelle; Vostanis, Panos

    2006-09-01

    The theoretical cognitive model of stress and coping provides a structure to obtain and analyse maternal perceptions of caring for children with learning disabilities who present severe problem behaviours. The Family Fund database identified 18 families who met the sample criteria of children aged five years to 15 years with severe to moderate learning disability presenting severe problem behaviour. Physical aggression was reported to be the primary behavioural problem for 13 of the children. Interviews undertaken with the main carer of the child at their home were taped and transcribed. The data were analysed using grounded theory techniques which identified 'secondary stressors' for the parent. These were social isolation, conflict, limitation of lifestyle and self-blame. It is proposed that the amalgamated impact of these can weaken parents' coping resources and, therefore, may prove to be as significant to the negative association with maternal wellbeing as the problem behaviour. PMID:16940342

  7. Unitary inequivalence as a problem for structural realism

    NASA Astrophysics Data System (ADS)

    French, Steven

    2012-05-01

    The existence of unitarily inequivalent representations in quantum field theory has been presented as a serious problem for structural realism. In this paper I explore two possible responses. The first involves adopting Wallace's 'naïve Lagrangian' interpretation of QFT and dismissing the generation of inequivalent representations as either a mathematical artefact or as non-pathological. The second takes up Ruetsche's 'Swiss Army Knife' approach and understands the relevant structure as spanning a range of possibilities. Both options present interesting implications for structural realism and I shall also consider related issues to do with underdetermination, the significance of spontaneous symmetry breaking and how we should understand superselection rules in the context of quantum statistics. Finally, I shall suggest a way in which these options might be combined.

  8. A Benchmark Problem for Development of Autonomous Structural Modal Identification

    NASA Technical Reports Server (NTRS)

    Pappa, Richard S.; Woodard, Stanley E.; Juang, Jer-Nan

    1996-01-01

    This paper summarizes modal identification results obtained using an autonomous version of the Eigensystem Realization Algorithm on a dynamically complex, laboratory structure. The benchmark problem uses 48 of 768 free-decay responses measured in a complete modal survey test. The true modal parameters of the structure are well known from two previous, independent investigations. Without user involvement, the autonomous data analysis identified 24 to 33 structural modes with good to excellent accuracy in 62 seconds of CPU time (on a DEC Alpha 4000 computer). The modal identification technique described in the paper is the baseline algorithm for NASA's Autonomous Dynamics Determination (ADD) experiment scheduled to fly on International Space Station assembly flights in 1997-1999.

  9. REVIEWS OF TOPICAL PROBLEMS: 21st century: what is life from the perspective of physics?

    NASA Astrophysics Data System (ADS)

    Ivanitskii, Genrikh R.

    2010-07-01

    The evolution of the biophysical paradigm over 65 years since the publication in 1944 of Erwin Schrödinger's What is Life? The Physical Aspects of the Living Cell is reviewed. Based on the advances in molecular genetics, it is argued that all the features characteristic of living systems can also be found in nonliving ones. Ten paradoxes in logic and physics are analyzed that allow defining life in terms of a spatial-temporal hierarchy of structures and combinatory probabilistic logic. From the perspective of physics, life can be defined as resulting from a game involving interactions of matter one part of which acquires the ability to remember the success (or failure) probabilities from the previous rounds of the game, thereby increasing its chances for further survival in the next round. This part of matter is currently called living matter.

  10. Recent advances, trends and new perspectives via enthalpy-based finite element formulations for applications to solidification problems

    NASA Technical Reports Server (NTRS)

    Tamma, Kumar K.; Namburu, Raju R.

    1990-01-01

    The present paper describes recent advances and trends in finite element developments and applications for solidification problems. In particular, in comparison to traditional methods of approach, new enthalpy-based architectures based on a generalized trapezoidal family of representations are presented which provide different perspectives, physical interpretation and solution architectures for effective numerical simulation of phase change processes encountered in solidification problems. Various numerical test models are presented and the results support the proposition for employing such formulations for general phase change applications.

  11. Using the Ethnographer's Perspective to Diagnose Problems in Educational Practice: The Experience of the New York Region of DTA.

    ERIC Educational Resources Information Center

    Lenoir, Teresa C.

    This paper describes the use of the ethnographer's perspective in applying research knowledge to the improvement of educational practice. The Documentation and Technical Assistance Project (DTA) uses ethnographic methods to study problem solving in urban public schools. In the complicated culture of the urban school, social, economic and political…

  12. Employability Skills, Personal Qualities, and Early Employment Problems of Entry-Level Auditors: Perspectives from Employers, Lecturers, Auditors, and Students

    ERIC Educational Resources Information Center

    Lim, Yet-Mee; Lee, Teck Heang; Yap, Ching Seng; Ling, Chui Ching

    2016-01-01

    The authors examine the issue of employability of university accounting students from the perspectives of accounting firm employers, junior auditors, accounting lecturers, and accounting students. Areas of investigation include perceived importance of employability skills and desirable personal qualities; and early employment problems encountered…

  13. 'Confidentiality smokescreens' and carers for people with mental health problems: the perspectives of professionals.

    PubMed

    Gray, Ben; Robinson, Catherine; Seddon, Diane; Roberts, Angela

    2008-07-01

    This paper reports on some of the findings from a collaborative study funded by the Big Lottery and led by Crossroads Caring for Carers about carers for people with mental health problems. The protection and use of information in mental health are firmly rooted in ethics and professional codes, law and policy, as well as values and professional practice. While government initiatives have attempted to augment the role and rights of carers, policy guidance involving information sharing between professionals and carers has failed to deal with the practical dilemmas of patient confidentiality. Professional codes and training neither explore nor develop the moral and ethical ground that stands between the service user's need for privacy and the carer's need for information. Policy and training guidance on confidentiality is scattered, ambiguous, confusing for professionals and inconsistent. There is uncertainty in practice about the information that professionals may share, and many professionals do not take into account carers' rights, not least to basic information to help them care for service users. 'Confidentiality smokescreens' may sometimes lead to information being withheld from carers. Professionals sometimes find it easier and safer to say nothing. In order to explore these issues from the perspectives of professionals, 65 participants were interviewed. The sample included directors and senior staff from the health, social care and voluntary sectors. Respondents were asked to comment at length on their understanding of confidentiality and information sharing with carers. Findings highlight confidentiality smokescreens that erect barriers that limit effective information sharing; issues involving confidentiality, risk management and carers in crisis; examples of good practice; and the need for the training of professionals on confidentiality issues and the rights of carers. This paper explores the challenge of confidentiality smokescreens from the perspective

  14. On path-following methods for structural failure problems

    NASA Astrophysics Data System (ADS)

    Stanić, Andjelka; Brank, Boštjan; Korelc, Jože

    2016-08-01

    We revisit the consistently linearized path-following method that can be applied in the nonlinear finite element analysis of solids and structures in order to compute a solution path. Within this framework, two constraint equations are considered: a quadratic one (that includes as special cases popular spherical and cylindrical forms of constraint equation), and another one that constrains only one degree-of-freedom (DOF), the critical DOF. In both cases, the constrained DOFs may vary from one solution increment to another. The former constraint equation is successful in analysing geometrically nonlinear and/or standard inelastic problems with snap-throughs, snap-backs and bifurcation points. However, it cannot handle problems with the material softening that are computed e.g. by the embedded-discontinuity finite elements. This kind of problems can be solved by using the latter constraint equation. The plusses and minuses of the both presented constraint equations are discussed and illustrated on a set of numerical examples. Some of the examples also include direct computation of critical points and branch switching. The direct computation of the critical points is performed in the framework of the path-following method by using yet another constraint function, which is eigenvector-free and suited to detect critical points.

  15. CALL FOR PAPERS: Special issue on the random search problem: trends and perspectives

    NASA Astrophysics Data System (ADS)

    da Luz, Marcos G. E.; Grosberg, Alexander Y.; Raposo, Ernesto P.; Viswanathan, Gandhi M.

    2008-11-01

    field. The subject can be approached from the perspective of different fields: ecology, networks, transport problems, molecular biology, etc. The study of the problem is particularly suited to the concepts and methods of statistical physics and stochastic processes; for example, fractals, random walks, anomalous diffusion. Discrete landscapes can be approached via graph theory, random lattices and complex networks. Such topics are regularly discussed in Journal of Physics A: Mathematical and Theoretical. All such aspects of the problem fall within the scope and focus of this special issue on the random search problem: trends and perspectives. Editorial policy All contributions to the special issue will be refereed in accordance with the refereeing policy of the journal. In particular, all research papers will be expected to be original work reporting substantial new results. The issue will also contain a number of review articles by invitation only. The Guest Editors reserve the right to judge whether a contribution fits the scope of the special issue. Guidelines for preparation of contributions We aim to publish the special issue in August 2009. To realize this, the DEADLINE for contributed papers is 15 January 2009. There is a page limit of 15 printed pages (approximately 9000 words) per contribution. For papers exceeding this limit, the Guest Editors reserve the right to request a reduction in length. Further advice on document preparation can be found at www.iop.org/Journals/jphysa. Contributions to the special issue should if possible be submitted electronically by web upload at www.iop.org/Journals/jphysa, or by email to jphysa@iop.org, quoting 'J. Phys. A Special Issue— Random Search Problem'. Please state whether the paper has been invited or is contributed. Submissions should ideally be in standard LaTeX form. Please see the website for further information on electronic submissions. Authors unable to submit electronically may send hard-copy contributions to

  16. Consumption, Ecological Footprints and Global Inequality: A Lesson in Individual and Structural Components of Environmental Problems

    ERIC Educational Resources Information Center

    Obach, Brian K.

    2009-01-01

    As evidence of the growing ecological crisis mounts, it is imperative that sociologists speak to this social problem and incorporate a sociological perspective on environmental issues into the curriculum. Central to understanding how social issues relate to environmental problems is an examination of the ties between consumption and its ecological…

  17. The Influence of Family Structure, the TPH2 G-703T and the 5-HTTLPR Serotonergic Genes upon Affective Problems in Children Aged 10-14 Years

    ERIC Educational Resources Information Center

    Nobile, Maria; Rusconi, Marianna; Bellina, Monica; Marino, Cecilia; Giorda, Roberto; Carlet, Ombretta; Vanzin, Laura; Molteni, Massimo; Battaglia, Marco

    2009-01-01

    Background: Both genetic and psychosocial risk factors influence the risk for depression in development. While the impacts of family structure and of serotonergic polymorphisms upon individual differences for affective problems have been investigated separately, they have never been considered together in a gene-environment interplay perspective.…

  18. Debates—Perspectives on socio-hydrology: Changing water systems and the "tyranny of small problems"—Socio-hydrology

    NASA Astrophysics Data System (ADS)

    Sivapalan, Murugesu

    2015-06-01

    We are well and truly in the Anthropocene. Humans can no longer be considered as mere external drivers or boundary conditions in the hydrologic systems we study. The interactions and feedbacks between human actions and water cycle dynamics on the planet, combined with the evolution of human norms/values in relation to water, are throwing up a range of emergent "big problems." Understanding and offering sustainable solutions to these "big problems" require a broadening of hydrologic science to embrace the perspectives of both social and natural scientists. The new science of socio-hydrology was introduced with this in mind, yet faces major challenges due to the wide gulf that separates the knowledge foundations and methodologies of natural and social sciences. Yet, the benefits of working together are enormous, including through adoption of natural science methods for social science problems, and vice versa. Bringing together the perspectives of both social and natural scientists dealing with water is good for hydrologic science, having the salutary effect of revitalizing it as use-inspired basic science. It is good for management too, in that the broader, holistic perspectives provided by socio-hydrology can help recognize potential "big" problems that may otherwise be unforeseen and, equally, identify potential "alternative" solutions to otherwise intractable problems.

  19. Perspectives of Urban Corner Store Owners and Managers on Community Health Problems and Solutions

    PubMed Central

    Young, Candace R.; Cannuscio, Carolyn C.; Karpyn, Allison; Kounaves, Sarah; Strupp, Emily; McDonough, Kevin; Shea, Judy A.

    2016-01-01

    Introduction Urban corner store interventions have been implemented to improve access to and promote purchase of healthy foods. However, the perspectives of store owners and managers, who deliver and shape these interventions in collaboration with nonprofit, government, and academic partners, have been largely overlooked. We sought to explore the views of store owners and managers on the role of their stores in the community and their beliefs about health problems and solutions in the community. Methods During 2013 and 2014, we conducted semistructured, in-depth interviews in Philadelphia, Pennsylvania, and Camden, New Jersey, with 23 corner store owners/managers who participated in the Healthy Corner Store Initiative spearheaded by The Food Trust, a nonprofit organization focused on food access in low-income communities. We oversampled high-performing store owners. Results Store owners/managers reported that their stores served multiple roles, including providing a convenient source of goods, acting as a community hub, supporting community members, working with neighborhood schools, and improving health. Owners/managers described many challenging aspects of running a small store, including obtaining high-quality produce at a good price and in small quantities. Store owners/managers believed that obesity, diabetes, high cholesterol, and poor diet are major problems in their communities. Some owners/managers engaged with customers to discuss healthy behaviors. Conclusion Our findings suggest that store owners and managers are crucial partners for healthy eating interventions. Corner store owners/managers interact with community members daily, are aware of community health issues, and are community providers of access to food. Corner store initiatives can be used to implement innovative programs to further develop the untapped potential of store owners/managers. PMID:27736054

  20. Representation and constraints: the inverse problem and the structure of visual space.

    PubMed

    Hatfield, Gary

    2003-11-01

    Visual space can be distinguished from physical space. The first is found in visual experience, while the second is defined independently of perception. Theorists have wondered about the relation between the two. Some investigators have concluded that visual space is non-Euclidean, and that it does not have a single metric structure. Here it is argued (1) that visual space exhibits contraction in all three dimensions with increasing distance from the observer, (2) that experienced features of this contraction (including the apparent convergence of lines in visual experience that are produced from physically parallel stimuli in ordinary viewing conditions) are not the same as would be the experience of a perspective projection onto a frontoparallel plane, and (3) that such contraction is consistent with size constancy. These properties of visual space are different from those that would be predicted if spatial perception resulted from the successful solution of the inverse problem. They are consistent with the notion that optical constraints have been internalized. More generally, they are also consistent with the notion that visual spatial structures bear a resemblance relation to physical spatial structures. This notion supports a type of representational relation that is distinct from mere causal correspondence. The reticence of some philosophers and psychologists to discuss the structure of phenomenal space is diagnosed in terms of the simple materialism and the functionalism of the 1970s and 1980s.

  1. Topographic mapping of oral structures - problems and applications in prosthodontics

    NASA Astrophysics Data System (ADS)

    Young, John M.; Altschuler, Bruce R.

    1981-10-01

    The diagnosis and treatment of malocclusion, and the proper design of restorations and prostheses, requires the determination of surface topography of the teeth and related oral structures. Surface contour measurements involve not only affected teeth, but adjacent and opposing surface contours composing a complexly interacting occlusal system. No a priori knowledge is predictable as dental structures are largely asymmetrical, non-repetitive, and non-uniform curvatures in 3-D space. Present diagnosis, treatment planning, and fabrication relies entirely on the generation of physical replicas during each stage of treatment. Fabrication is limited to materials that lend themselves to casting or coating, and to hand fitting and finishing. Inspection is primarily by vision and patient perceptual feedback. Production methods are time-consuming. Prostheses are entirely custom designed by manual methods, require costly skilled technical labor, and do not lend themselves to centralization. The potential improvement in diagnostic techniques, improved patient care, increased productivity, and cost-savings in material and man-hours that could result, if rapid and accurate remote measurement and numerical (automated) fabrication methods were devised, would be significant. The unique problems of mapping oral structures, and specific limitations in materials and methods, are reviewed.

  2. [Factorial structure and reliability of Zimbardo Time Perspective Inventory].

    PubMed

    Díaz-Morales, Juan Francisco

    2006-08-01

    Time orientation is a fundamental psychological variable, what it flows all aspects of human behaviour. Past, present, and future orientation decomposed of allocated into different temporal frames the continual flow of behaviour, providing meaning and coherence. It has been proposed the Zimbardo Time Perspective Inventory (ZTPI) so multidimensional measure of time orientation, which include positive and negative evaluation of past and present, as well as future evaluation. The factorial structure and reliability of ZTPI was analysed on Spanish adult population. The participants were 756 adults with age range 19-67 years old ( M = 40.1, SD = 15.45). The principal components analyses showed five factors, very similar to obtain on nort-american undergraduate samples, even thought a little difference in composition of the present-fatalist factor. The reliability of each factor was suitable. Age and gender differences analysis showed that older groups were more future oriented and less present hedonist, female were high orientation to past negative, past positive and present fatalist, while young females were more future oriented than older females.

  3. Evolutionary perspectives of telomerase RNA structure and function.

    PubMed

    Podlevsky, Joshua D; Chen, Julian J-L

    2016-08-01

    Telomerase is the eukaryotic solution to the 'end-replication problem' of linear chromosomes by synthesising the highly repetitive DNA constituent of telomeres, the nucleoprotein cap that protects chromosome termini. Functioning as a ribonucleoprotein (RNP) enzyme, telomerase is minimally composed of the highly conserved catalytic telomerase reverse transcriptase (TERT) and essential telomerase RNA (TR) component. Beyond merely providing the template for telomeric DNA synthesis, TR is an innate telomerase component and directly facilitates enzymatic function. TR accomplishes this by having evolved structural elements for stable assembly with the TERT protein and the regulation of the telomerase catalytic cycle. Despite its prominence and prevalence, TR has profoundly diverged in length, sequence, and biogenesis pathway among distinct evolutionary lineages. This diversity has generated numerous structural and mechanistic solutions for ensuring proper RNP formation and high fidelity telomeric DNA synthesis. Telomerase provides unique insights into RNA and protein coevolution within RNP enzymes. PMID:27359343

  4. Visualizing the Structure of Medical Informatics Using Term Co-Occurrence Analysis: II. INSPEC Perspective.

    ERIC Educational Resources Information Center

    Morris, Theodore

    2001-01-01

    Term co-occurrence analysis of INSPEC classification codes and thesaurus terms used to index Medical Informatics literature reveals an information science and technology perspective on the field, to accompany the biomedical perspective previously reported. This study continues the search for a better understanding of the structure of Medical…

  5. Symplectic structures related with higher order variational problems

    NASA Astrophysics Data System (ADS)

    Kijowski, Jerzy; Moreno, Giovanni

    2015-06-01

    In this paper, we derive the symplectic framework for field theories defined by higher order Lagrangians. The construction is based on the symplectic reduction of suitable spaces of iterated jets. The possibility of reducing a higher order system of partial differential equations to a constrained first-order one, the symplectic structures naturally arising in the dynamics of a first-order Lagrangian theory, and the importance of the Poincaré-Cartan form for variational problems, are all well-established facts. However, their adequate combination corresponding to higher order theories is missing in the literature. Here we obtain a consistent and truly finite-dimensional canonical formalism, as well as a higher order version of the Poincaré-Cartan form. In our exposition, the rigorous global proofs of the main results are always accompanied by their local coordinate descriptions, indispensable to work out practical examples.

  6. Global structure of the multiverse and the measure problem

    NASA Astrophysics Data System (ADS)

    Vilenkin, Alexander

    2013-02-01

    An unresolved question in inflationary cosmology is the assignment of probabilities to different types of events that can occur in the eternally inflating multiverse. We explore the possibility that the resolution of this "measure problem" may rely on non-standard dynamics in regions of high curvature. In particular, "big crunch" singularities that develop in bubbles with negative vacuum energy density may lead to bounces, where contraction is replaced by inflationary expansion. Similarly, singularities inside of black holes might be gateways to other inflating vacua. This would drastically affect the global structure of the multiverse. We consider a measure based on a probe geodesic which undergoes an infinite number of passages through crunches. This can be thought of as the world-line of an eternal "watcher", collecting data in an orderly fashion. This watcher's measure is independent of initial conditions and does not suffer from ambiguities associated with the choice of a cut-off surface.

  7. Solving Optimal Control Problems by Exploiting Inherent Dynamical Systems Structures

    NASA Astrophysics Data System (ADS)

    Flaßkamp, Kathrin; Ober-Blöbaum, Sina; Kobilarov, Marin

    2012-08-01

    Computing globally efficient solutions is a major challenge in optimal control of nonlinear dynamical systems. This work proposes a method combining local optimization and motion planning techniques based on exploiting inherent dynamical systems structures, such as symmetries and invariant manifolds. Prior to the optimal control, the dynamical system is analyzed for structural properties that can be used to compute pieces of trajectories that are stored in a motion planning library. In the context of mechanical systems, these motion planning candidates, termed primitives, are given by relative equilibria induced by symmetries and motions on stable or unstable manifolds of e.g. fixed points in the natural dynamics. The existence of controlled relative equilibria is studied through Lagrangian mechanics and symmetry reduction techniques. The proposed framework can be used to solve boundary value problems by performing a search in the space of sequences of motion primitives connected using optimized maneuvers. The optimal sequence can be used as an admissible initial guess for a post-optimization. The approach is illustrated by two numerical examples, the single and the double spherical pendula, which demonstrates its benefit compared to standard local optimization techniques.

  8. Sparse Solution of High-Dimensional Model Calibration Inverse Problems under Uncertainty in Prior Structural Connectivity

    NASA Astrophysics Data System (ADS)

    Mohammad khaninezhad, M.; Jafarpour, B.

    2012-12-01

    Data limitation and heterogeneity of the geologic formations introduce significant uncertainty in predicting the related flow and transport processes in these environments. Fluid flow and displacement behavior in subsurface systems is mainly controlled by the structural connectivity models that create preferential flow pathways (or barriers). The connectivity of extreme geologic features strongly constrains the evolution of the related flow and transport processes in subsurface formations. Therefore, characterization of the geologic continuity and facies connectivity is critical for reliable prediction of the flow and transport behavior. The goal of this study is to develop a robust and geologically consistent framework for solving large-scale nonlinear subsurface characterization inverse problems under uncertainty about geologic continuity and structural connectivity. We formulate a novel inverse modeling approach by adopting a sparse reconstruction perspective, which involves two major components: 1) sparse description of hydraulic property distribution under significant uncertainty in structural connectivity and 2) formulation of an effective sparsity-promoting inversion method that is robust against prior model uncertainty. To account for the significant variability in the structural connectivity, we use, as prior, multiple distinct connectivity models. For sparse/compact representation of high-dimensional hydraulic property maps, we investigate two methods. In one approach, we apply the principle component analysis (PCA) to each prior connectivity model individually and combine the resulting leading components from each model to form a diverse geologic dictionary. Alternatively, we combine many realizations of the hydraulic properties from different prior connectivity models and use them to generate a diverse training dataset. We use the training dataset with a sparsifying transform, such as K-SVD, to construct a sparse geologic dictionary that is robust to

  9. Numerical Simulation of Liquid-Structure Interaction Problems in a Tank for Aerospace Applications

    NASA Astrophysics Data System (ADS)

    Bucchignani, E.; Pezzella, G.; Matrone, A.

    2009-01-01

    The current perspectives in the aerospace require a particular care for the analysis of several phenomena involving the coupling between the mechanical behaviour and other physics fields such as the fluid- structure interaction problem. This issue is particularly felt within the Reusable Launch Vehicle (RLV) design since, during reentry, such kind of vehicles carries large quantities of Main Engine Cut Off (MECO) residual propellants. The management of the residual propellant remaining in the reusable stage after MECO during a nominal mission is a crucial point for the design with respect to: dimensioning and weight, landing safety issues, and post landing procedures. The goal of this paper is the unsteady numerical simulation of a RLV-like tank configuration, filled with propellant, such as liquid Oxygen (LO2) and/or liquid Hydrogen (LH2), subject to a typical reentry loading environment. The flowfield pressure and the stress field in the tank structure have been evaluated considering the motion of an incompressible fluid with a mobile free surface, in a tank with deforming walls under the action of the liquid pressure. An unsteady Finite Element formulation is used, instead, for modelling the tank. The coupling algorithm, based on a staggered method, belongs to the class of the partition treatment techniques, which allow to solve the fluid and structural fields by means of two distinct models.

  10. PERSPECTIVE VIEW OF THE C. 1925 AUTO SALES/GARAGE STRUCTURE LOCATED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PERSPECTIVE VIEW OF THE C. 1925 AUTO SALES/GARAGE STRUCTURE LOCATED AT 205-209 SECOND STREET NORTHWEST. - Corvallis Downtown Historic District, Bounded by First & Sixth Streets, Van Buren & Western Avenues, Corvallis, Benton County, OR

  11. Perspectives on Sleep, Sleep Problems, and Their Treatment, in People with Serious Mental Illnesses: A Systematic Review

    PubMed Central

    Bee, Penny

    2016-01-01

    Sleep problems are common in people with serious mental illness, and impact negatively on functioning and wellbeing. To understand the development of sleep problems, their maintenance, and their treatment, an in depth understanding of patient perspectives is crucial. A systematic literature review was conducted using Medline, AMED, PsychInfo, Embase and CINAHL. Qualitative and quantitative studies were included if they explored or measured patient perspectives on sleep, sleep problems or sleep treatments in people with serious mental illness. Of the 2,067 hits, only 22 met review inclusion criteria, and high quality evidence was sparse. The limited findings suggested sleep was seen as highly interlinked with mental health. Evaluations of treatments varied, however perceived efficacy and personalisation of treatments were valued. Some evidence suggested patient priorities and conceptualisations regarding sleep may diverge from those of validated screening tools developed in general population and sleep medicine samples. More rigorous research is needed to support adaptation and development of interventions and outcome measures for use in specialist mental health settings. Qualitative studies exploring the experience of sleep disturbance in particular diagnostic groups and contexts are urgently required, as are patient perspectives on sleep interventions. PMID:27657927

  12. Effects of a Problem-Based Structure of Physics Contents on Conceptual Learning and the Ability to Solve Problems

    ERIC Educational Resources Information Center

    Becerra-Labra, Carlos; Gras-Marti, Albert; Torregrosa, Joaquin Martinez

    2012-01-01

    A model of teaching/learning is proposed based on a "problem-based structure" of the contents of the course, in combination with a training in paper and pencil problem solving that emphasizes discussion and quantitative analysis, rather than formulae plug-in. The aim is to reverse the high failure and attrition rate among engineering…

  13. Detangling the Interrelationships between Self- Regulation and Ill-Structured Problem Solving in Problem-Based Learning

    ERIC Educational Resources Information Center

    Ge, Xun; Law, Victor; Huang, Kun

    2016-01-01

    One of the goals for problem-based learning (PBL) is to promote self-regulation. Although self-regulation has been studied extensively, its interrelationships with ill-structured problem solving have been unclear. In order to clarify the interrelationships, this article proposes a conceptual framework illustrating the iterative processes among…

  14. Applying Quantum Monte Carlo to the Electronic Structure Problem

    NASA Astrophysics Data System (ADS)

    Powell, Andrew D.; Dawes, Richard

    2016-06-01

    Two distinct types of Quantum Monte Carlo (QMC) calculations are applied to electronic structure problems such as calculating potential energy curves and producing benchmark values for reaction barriers. First, Variational and Diffusion Monte Carlo (VMC and DMC) methods using a trial wavefunction subject to the fixed node approximation were tested using the CASINO code.[1] Next, Full Configuration Interaction Quantum Monte Carlo (FCIQMC), along with its initiator extension (i-FCIQMC) were tested using the NECI code.[2] FCIQMC seeks the FCI energy for a specific basis set. At a reduced cost, the efficient i-FCIQMC method can be applied to systems in which the standard FCIQMC approach proves to be too costly. Since all of these methods are statistical approaches, uncertainties (error-bars) are introduced for each calculated energy. This study tests the performance of the methods relative to traditional quantum chemistry for some benchmark systems. References: [1] R. J. Needs et al., J. Phys.: Condensed Matter 22, 023201 (2010). [2] G. H. Booth et al., J. Chem. Phys. 131, 054106 (2009).

  15. An embodied perspective on expertise in solving the problem of making a geologic map

    NASA Astrophysics Data System (ADS)

    Callahan, Caitlin Norah

    The task of constructing a geologic map is a cognitively and physically demanding field-based problem. The map produced is understood to be an individual's two-dimensional interpretation or mental model of the three-dimensional underlying geology. A popular view within the geoscience community is that teaching students how to make a geologic map is valuable for preparing them to deal with disparate and incomplete data sets, for helping them develop problem-solving skills, and for acquiring expertise in geology. Few previous studies have focused specifically on expertise in geologic mapping. Drawing from literature related to expertise, to problem solving, and to mental models, two overarching research questions were identified: How do geologists of different levels of expertise constrain and solve an ill-structured problem such as making a geologic map? How do geologists address the uncertainties inherent to the processes and interpretations involved in solving a geologic mapping problem? These questions were answered using a methodology that captured the physical actions, expressed thoughts, and navigation paths of geologists as they made a geologic map. Eight geologists, from novice to expert, wore a head-mounted video camera with an attached microphone to record those actions and thoughts, creating "video logs" while in the field. The video logs were also time-stamped, which allowed the visual and audio data to be synchronized with the GPS data that tracked participants' movements in the field. Analysis of the video logs yielded evidence that all eight participants expressed thoughts that reflected the process of becoming mentally situated in the mapping task (e.g. relating between distance on a map and distance in three-dimensional space); the prominence of several of these early thoughts waned in the expressed thoughts later in the day. All participants collected several types of data while in the field; novices, however, did so more continuously throughout

  16. Semantic Annotation of Complex Text Structures in Problem Reports

    NASA Technical Reports Server (NTRS)

    Malin, Jane T.; Throop, David R.; Fleming, Land D.

    2011-01-01

    Text analysis is important for effective information retrieval from databases where the critical information is embedded in text fields. Aerospace safety depends on effective retrieval of relevant and related problem reports for the purpose of trend analysis. The complex text syntax in problem descriptions has limited statistical text mining of problem reports. The presentation describes an intelligent tagging approach that applies syntactic and then semantic analysis to overcome this problem. The tags identify types of problems and equipment that are embedded in the text descriptions. The power of these tags is illustrated in a faceted searching and browsing interface for problem report trending that combines automatically generated tags with database code fields and temporal information.

  17. Assisting Workers Displaced by Structural Change. An International Perspective.

    ERIC Educational Resources Information Center

    Leigh, Duane E.

    This monograph takes the perspective that increased awareness of how active labor market programs operate in other nations can substantially improve the way in which the United States deals with worker displacement. Chapter 1 considers the costs of worker displacement and how government programs designed to reduce these costs are evaluated.…

  18. Incremental Validity and Informant Effect from a Multi-Method Perspective: Assessing Relations between Parental Acceptance and Children’s Behavioral Problems

    PubMed Central

    Izquierdo-Sotorrío, Eva; Holgado-Tello, Francisco P.; Carrasco, Miguel Á.

    2016-01-01

    This study examines the relationships between perceived parental acceptance and children’s behavioral problems (externalizing and internalizing) from a multi-informant perspective. Using mothers, fathers, and children as sources of information, we explore the informant effect and incremental validity. The sample was composed of 681 participants (227 children, 227 fathers, and 227 mothers). Children’s (40% boys) ages ranged from 9 to 17 years (M = 12.52, SD = 1.81). Parents and children completed both the Parental Acceptance Rejection/Control Questionnaire (PARQ/Control) and the check list of the Achenbach System of Empirically Based Assessment (ASEBA). Statistical analyses were based on the correlated uniqueness multitrait-multimethod matrix (model MTMM) by structural equations and different hierarchical regression analyses. Results showed a significant informant effect and a different incremental validity related to which combination of sources was considered. A multi-informant perspective rather than a single one increased the predictive value. Our results suggest that mother–father or child–father combinations seem to be the best way to optimize the multi-informant method in order to predict children’s behavioral problems based on perceived parental acceptance. PMID:27242582

  19. Practice Constraints, Behavioral Problems, and Dementia Care: Primary Care Physicians’ Perspectives

    PubMed Central

    Hinton, Ladson; Reddy, Geetha; Flores, Yvette; Kravitz, Richard L.; Barker, Judith C.

    2007-01-01

    Objectives To examine how practice constraints contribute to barriers in the health care of persons with dementia and their families, particularly with respect to behavioral aspects of care. Design Cross-sectional qualitative interview study of primary care physicians. Setting Physicians’ offices. Participants Forty primary care physicians in Northern California. Measurements Open-ended interviews lasted 30–60 minutes and were structured by an interview guide covering clinician background and practice setting, clinical care of a particular patient, and general approach to managing patients with AD or dementia. Interviews were transcribed and themes reflecting constraints of practice were identified through a systematic coding process. Results Recurring themes (i.e., those present in ≥25% of physician interviews) included insufficient time, difficulty in accessing and communicating with specialists, low reimbursement, poor connections with community social service agencies, and lack of interdisciplinary teams. Physician narratives suggest that these constraints may lead to delayed detection of behavior problems, “reactive” as opposed to proactive management of dementia, and increased reliance on pharmacological rather than psychosocial approaches. Conclusion Physicians often feel challenged in caring for dementia patients, particularly those who are more behaviorally complex, because of time and reimbursement constraints as well as other perceived barriers. Our results suggest that more effective educational interventions (for families and physicians) and broader structural changes are needed to better meet the needs of the elderly with dementia and their families now and in the future. Without these changes, dementia care is likely to continue to fall short. PMID:17823840

  20. Historical perspective: The problem of the origin of life in the context of developments in biology

    NASA Astrophysics Data System (ADS)

    Kamminga, Harmke

    1988-03-01

    The structure of the history of scientific ideas on the origin of life, after Darwin's theory of evolution brought the problem into focus, is discussed. 19th-century theories in the mainstream of historical development already included some notion of chemical evolution. These theories were limited, however, by their reliance on a protoplasmic view of life, according to which the protoplasmic substance combines all vital properties. It was only when this holistic concept of protoplasm was abandoned that a clear distinction between different vital functions such as metabolism and replication was made. This led to two schools of thought in the origin of life field, one inspired by biochemistry and one by genetics. Oparin's theory, which was rooted in the metabolic traditions of biochemistry, provided a model which has had a lasting impact in methodological terms and which helped to transform the field from a largely theoretical one to an area of active research. Genetically based theories, on the other hand, had a delayed impact in this respect, because of long-lasting uncertainty regarding the structural basis of gene function.

  1. The Nature and Use of Open Problems in Mathematics Education: Mathematical and Pedagogical Perspectives.

    ERIC Educational Resources Information Center

    Silver, Edward A.

    1995-01-01

    Discusses varieties of open-ended problems in mathematics, including problems that are unsolved in the field of mathematics, are open with respect to solution method, are open to interpretation of the problem or solutions, or that invite other problems as follow-up. (Author/MKR)

  2. On the Structure of the Fixed Charge Transportation Problem

    ERIC Educational Resources Information Center

    Kowalski, K.

    2005-01-01

    This work extends the theory of the fixed charge transportation problem (FCTP), currently based mostly on a forty-year-old publication by Hirsch and Danzig. This paper presents novel properties that need to be considered by those using existing, or those developing new methods for optimizing FCTP. It also defines the problem in an easier way,…

  3. Mathematical Abstraction in the Solving of Ill-Structured Problems by Elementary School Students in Korea

    ERIC Educational Resources Information Center

    Hong, Jee Yun; Kim, Min Kyeong

    2016-01-01

    Ill-structured problems can be regarded as one of the measures that meet recent social needs emphasizing students' abilities to solve real-life problems. This study aimed to analyze the mathematical abstraction process in solving such problems, and to identify the mathematical abstraction level ([I] Recognition of mathematical structure through…

  4. Pre-Service Elementary Teachers' Motivation and Ill-Structured Problem Solving in Korea

    ERIC Educational Resources Information Center

    Kim, Min Kyeong; Cho, Mi Kyung

    2016-01-01

    This article examines the use and application of an ill-structured problem to pre-service elementary teachers in Korea in order to find implications of pre-service teacher education with regard to contextualized problem solving by analyzing experiences of ill-structured problem solving. Participants were divided into small groups depending on the…

  5. Solution to certain problems in the failure of composite structures

    NASA Astrophysics Data System (ADS)

    Goodsell, Johnathan

    The present work contains the solution of two problems in composite structures. In the first, an approximate elasticity solution for prediction of the displacement, stress and strain fields within the m-layer, symmetric and balanced angle-ply composite laminate of finite-width subjected anticlastic bending deformation is developed. The solution is shown to recover classical laminated plate theory predictions at interior regions of the laminate and thereby illustrates the boundary layer character of this interlaminar phenomenon. The results exhibit the anticipated response in congruence with the solutions for uniform axial extension and uniform temperature change, where divergence of the interlaminar shearing stress is seen to occur at the intersection of the free-edge and planes between lamina of +theta and -theta orientation. The analytical results show excellent agreement with the finite-element predictions for the same boundary-value problem and thereby provide an efficient and compact solution available for parametric studies of the influence of geometry and material properties. The solution is combined with previously developed solutions for uniform axial extension and uniform temperature change of the identical laminate and the combined solution is exercised to compare the relative magnitudes of free-edge phenomenon arising from the different loading conditions, to study very thick laminates and laminates where the laminate width is less than the laminate thickness. Significantly, it was demonstrated that the solution is valid for arbitrary stacking sequence and the solution was exercised to examine antisymmetric and non-symmetric laminates. Finally, the solution was exercised to determine the dimensions of the boundary layer for very large numbers of layers. It was found that the dimension of the boundary layer width in bending is approximately twice that in uniform axial extension and uniform temperature change. In the second, the intrinsic flaw concept is

  6. The Space Physics ``Data Problem'' from the Perspectives of Different Stakeholders (Invited)

    NASA Astrophysics Data System (ADS)

    Donovan, E. F.

    2010-12-01

    Researchers, the PIs of VOs, and funding agencies frequently refer to an overarching “the data problem”. The Heliophysical Data Environment and other programs in the US and around the world have been put in place to address this issue. The data environment in space physics has evolved significantly in the last decade, and as a result there has been a dramatic and definitely positive increase in the effectiveness of systems for delivery of data to the research community. This has manifested itself in the form of in general much shorter (frequently less than a day) times between observation and the availability of scientific data products, greater uniformity in and long-term stability of file types and structures, the implementation of metadata standards, the establishment of remarkably effective summary plots and web-based browsing tools, and the growing availability of software that makes working with the scientific data products much easier than it used to be. Still, there are issues related to data and data services that need to be revisited as the data environment continues to evolve. Foremost in my mind is a sense that from the perspectives of funding agencies, producers of different types of data, and data users there is certainly not one “data problem”. For example, as a general rule funding agencies want data widely used, while university researchers who are producing data want to lead discovery-type research that uses that data in some key way. The PI of a big project usually benefits optimally if the data is totally open and widely utilized, while the interests of a grad student carrying out a project that centers in some way on data are often best served by a possibly years-long period during which access to that specific data is not open to the broader community. Novice or one-time users of a type of data are often best served by a web-based tool that will make a straightforward plot for them, while expert users usually just want access to a

  7. "The Problem of Trinity College Dublin": A Historical Perspective on Rationalisation in Higher Education in Ireland

    ERIC Educational Resources Information Center

    Walsh, John

    2014-01-01

    This paper offers a historical perspective on government policies for the rationalisation of higher education (HE) in Ireland through a critical re-appraisal of the initiative for "merger" of Trinity College and University College Dublin. The initiative launched by Donogh O'Malley in 1967 was the first significant attempt by an…

  8. When Your "Problem" Becomes Mine: Adult Female Siblings' Perspectives of Having a Brother with a Disability

    ERIC Educational Resources Information Center

    Pompeo, Michelle N.

    2009-01-01

    This study is a retrospective look at adult female siblings' perspectives of their childhoods and present identities based on having a brother with a disability. This paper focuses on siblings' experiences within educational and public domains, and how such experiences have shaped their personalities and career choices. Qualitative findings were…

  9. The Problem of the Pyramid or Egyptian Mathematics from a Postmodern Perspective

    ERIC Educational Resources Information Center

    Shutler, Paul M. E.

    2009-01-01

    We consider Egyptian mathematics from a postmodern perspective, by which we mean suspending judgement as to strict correctness in order to appreciate the genuine mathematical insights which they did have in the context in which they were working. In particular we show that the skill which the Egyptians possessed of obtaining the general case from…

  10. The Problem of Data in the Cognitive Linguistic Research on Metonymy: A Cross-Linguistic Perspective

    ERIC Educational Resources Information Center

    Brdar-Szabo, Rita; Brdar, Mario

    2012-01-01

    The general goal of the present paper is to demonstrate how cross-linguistic (contrastive) data can broaden the perspective in cognitive linguistic research on metonymy, which may raise a host of questions calling for a revision of some widely accepted views. A more specific, methodological goal is to show how the introspection-driven research and…

  11. How Can One Learn Mathematical Word Problems in a Second Language? A Cognitive Load Perspective

    ERIC Educational Resources Information Center

    Moussa-Inaty, Jase; Causapin, Mark; Groombridge, Timothy

    2015-01-01

    Language may ordinarily account for difficulties in solving word problems and this is particularly true if mathematical word problems are taught in a language other than one's native language. Research into cognitive load may offer a clear theoretical framework when investigating word problems because memory, specifically working memory, plays a…

  12. Parent and Teacher Perspectives about Problem Behavior in Children with Williams Syndrome

    ERIC Educational Resources Information Center

    Klein-Tasman, Bonita P.; Lira, Ernesto N.; Li-Barber, Kirsten T.; Gallo, Frank J.; Brei, Natalie G.

    2015-01-01

    Problem behavior of 52 children with Williams syndrome ages 6 to 17 years old was examined based on both parent and teacher report. Generally good inter-rater agreement was found. Common areas of problem behavior based both on parent and teacher report included attention problems, anxiety difficulties, repetitive behaviors (e.g., obsessions,…

  13. Middle School Children's Problem-Solving Behavior: A Cognitive Analysis from a Reading Comprehension Perspective

    ERIC Educational Resources Information Center

    Pape, Stephen J.

    2004-01-01

    Many children read mathematics word problems and directly translate them to arithmetic operations. More sophisticated problem solvers transform word problems into object-based or mental models. Subsequent solutions are often qualitatively different because these models differentially support cognitive processing. Based on a conception of problem…

  14. Integrated Force Method Solution to Indeterminate Structural Mechanics Problems

    NASA Technical Reports Server (NTRS)

    Patnaik, Surya N.; Hopkins, Dale A.; Halford, Gary R.

    2004-01-01

    Strength of materials problems have been classified into determinate and indeterminate problems. Determinate analysis primarily based on the equilibrium concept is well understood. Solutions of indeterminate problems required additional compatibility conditions, and its comprehension was not exclusive. A solution to indeterminate problem is generated by manipulating the equilibrium concept, either by rewriting in the displacement variables or through the cutting and closing gap technique of the redundant force method. Compatibility improvisation has made analysis cumbersome. The authors have researched and understood the compatibility theory. Solutions can be generated with equal emphasis on the equilibrium and compatibility concepts. This technique is called the Integrated Force Method (IFM). Forces are the primary unknowns of IFM. Displacements are back-calculated from forces. IFM equations are manipulated to obtain the Dual Integrated Force Method (IFMD). Displacement is the primary variable of IFMD and force is back-calculated. The subject is introduced through response variables: force, deformation, displacement; and underlying concepts: equilibrium equation, force deformation relation, deformation displacement relation, and compatibility condition. Mechanical load, temperature variation, and support settling are equally emphasized. The basic theory is discussed. A set of examples illustrate the new concepts. IFM and IFMD based finite element methods are introduced for simple problems.

  15. [Problems of formal organizational structure of industrial health care complexes].

    PubMed

    Włodarczyk, C

    1978-01-01

    The author formulates the thesis that the description of organizational structure of industrial health care complex calls for isolation of the following aspects:--structure of territorial links--systemof organizational units and divisions--organization of basic functions--structure of management--structure of supervision of middle and lowe-level personnel--composition of health care complex council--system of accessibility ranges. Each of the above aspects has been considered on the basis of operative rules of law, using organizational analysis methods.

  16. Hybrid schemes based on quantum mechanics/molecular mechanics simulations goals to success, problems, and perspectives.

    PubMed

    Ferrer, Silvia; Ruiz-Pernía, Javier; Martí, Sergio; Moliner, Vicent; Tuñón, Iñaki; Bertrán, Juan; Andrés, Juan

    2011-01-01

    The development of characterization techniques, advanced synthesis methods, as well as molecular modeling has transformed the study of systems in a well-established research field. The current research challenges in biocatalysis and biotransformation evolve around enzyme discovery, design, and optimization. How can we find or create enzymes that catalyze important synthetic reactions, even reactions that may not exist in nature? What is the source of enzyme catalytic power? To answer these and other related questions, the standard strategies have evolved from trial-and-error methodologies based on chemical knowledge, accumulated experience, and common sense into a clearly multidisciplinary science that allows one to reach the molecular design of tailor-made enzyme catalysts. This is even more so when one refers to enzyme catalysts, for which the detailed structure and composition are known and can be manipulated to introduce well-defined residues which can be implicated in the chemical rearrangements taking place in the active site. The methods and techniques of theoretical and computational chemistry are becoming more and more important in both understanding the fundamental biological roles of enzymes and facilitating their utilization in biotechnology. Improvement of the catalytic function of enzymes is important from scientific and industrial viewpoints, and to put this fact in the actual perspective as well as the potentialities, we recommend the very recent report of Sanderson [Sanderson, K. (2011). Chemistry: enzyme expertise. Nature 471, 397.]. Great fundamental advances have been made toward the ab initio design of enzyme catalysts based on molecular modeling. This has been based on the molecular mechanistic knowledge of the reactions to be catalyzed, together with the development of advanced synthesis and characterization techniques. The corresponding molecular mechanism can be studied by means of powerful quantum chemical calculations. The catalytic

  17. Structuring Video Cases to Support Future Teachers' Problem Solving

    ERIC Educational Resources Information Center

    Kale, Ugur; Whitehouse, Pamela

    2012-01-01

    This study examined preservice teachers' problem-solving skills through the use of an online video case study. Eighty preservice teachers participated in the study with a three-level video presentation by a two-grade-level between-subjects factorial design. The study incorporates a content analysis framework to examine both the components and the…

  18. Perspectives

    ERIC Educational Resources Information Center

    Tarone, Elaine

    2013-01-01

    The topic of this "Perspectives" column is "Requiring a Proficiency Level as a Requirement for U.S. K-12 Teacher Licensure." In 1998, the American Council of Teachers of Foreign Languages (ACTFL) began to work with the National Council for Accreditation of Teacher Education (NCATE), which accredits teacher education programs…

  19. Perspectives.

    ERIC Educational Resources Information Center

    Robertson, Shari; Camerini, Michael

    2001-01-01

    Provides background information on the U.S. Immigration and Naturalization Service Asylum office. Uses the perspective of two movie producers as they filmed a documentary film, "Well-founded Fear", about asylum and refugee protection. Includes information on how to order a classroom aid and the film. (CMK)

  20. Boundary value problems of explicit ordinary differential equations from probabilistic evolution perspective

    NASA Astrophysics Data System (ADS)

    Demiralp, Metin

    2012-11-01

    The boundary value problems of ordinary differential equations have many important features in comparison with the initial value problems of ODEs. However, one of the basic tendencies is to evaluate forward and backward evolutions and then to combine them to satisfy the boundary conditions. One other issue is also the possibility of more than one type of problems: eigenvalue problems and inversion problems. In this or that way, the basic issue is the solution of ODEs. We use a recently developed method we call "Probabilistic Evolution Approach" whose mainlines are recalled in this paper. Then the boundary condition are imposed for the resulting infinite number of ODEs. This is perhaps the most elementary but promising approach to the boundary value problems of ODEs and works not only for linear but also for nonlinear ODEs.

  1. The Structure of the Help-Seeking Process in Collaboratively Using a Computer Coach in Problem-Based Learning

    ERIC Educational Resources Information Center

    Mercier, Julien; Frederiksen, Carl

    2008-01-01

    Research on help seeking with a computer coach providing on-demand help has not produced fully adequate models of the process from a cognitive perspective. The present study postulates a model of help seeking from a cognitive perspective and tests this model in a learning situation characterized as problem-based and computer-supported. The…

  2. The problem of disposing of plaster waste from building sites: problem structuring based on value focus thinking methodology.

    PubMed

    Alencar, Luciana Hazin; Mota, Caroline Maria de Miranda; Alencar, Marcelo Hazin

    2011-12-01

    Plaster is a material which is widely used in Brazil on construction sites. However, its use in recent years has been limited by a legal resolution on the environment introduced in Brazil. One of the regions most affected by these restrictions is the Northeast where the strategic importance of plaster for the region is apparent from the extensive economic development, centered on the gypsum pole of Araripe in the state of Pernambuco. This problem has involved many interested parties, among whom are plaster producers, plastering companies, builders, unions (for plaster workers, and construction workers), Town Halls, and so forth. Therefore, there is a need to structure the problem with a view to obtaining a better understanding of the problem given the lack of information on the real decision problem. To reach this objective, value focus thinking (VFT), a methodology that addresses how values can be used to improve the decision making process, was applied and the problem was structured. Thus, it was possible for the parties involved to clarify their objectives, and specify more precisely the consequences and constraints for the decision problem. In addition, each party involved could get a better understanding of their own wishes. In conclusion, the VFT methodology application enables the parties involved to make more consistent decisions, and therefore to ensure that plaster will continue to be used in the construction industry.

  3. The problem of disposing of plaster waste from building sites: problem structuring based on value focus thinking methodology.

    PubMed

    Alencar, Luciana Hazin; Mota, Caroline Maria de Miranda; Alencar, Marcelo Hazin

    2011-12-01

    Plaster is a material which is widely used in Brazil on construction sites. However, its use in recent years has been limited by a legal resolution on the environment introduced in Brazil. One of the regions most affected by these restrictions is the Northeast where the strategic importance of plaster for the region is apparent from the extensive economic development, centered on the gypsum pole of Araripe in the state of Pernambuco. This problem has involved many interested parties, among whom are plaster producers, plastering companies, builders, unions (for plaster workers, and construction workers), Town Halls, and so forth. Therefore, there is a need to structure the problem with a view to obtaining a better understanding of the problem given the lack of information on the real decision problem. To reach this objective, value focus thinking (VFT), a methodology that addresses how values can be used to improve the decision making process, was applied and the problem was structured. Thus, it was possible for the parties involved to clarify their objectives, and specify more precisely the consequences and constraints for the decision problem. In addition, each party involved could get a better understanding of their own wishes. In conclusion, the VFT methodology application enables the parties involved to make more consistent decisions, and therefore to ensure that plaster will continue to be used in the construction industry. PMID:21816597

  4. Sampling problems: The small scale structure of precipitation

    NASA Technical Reports Server (NTRS)

    Crane, R. K.

    1981-01-01

    The quantitative measurement of precipitation characteristics for any area on the surface of the Earth is not an easy task. Precipitation is rather variable in both space and time, and the distribution of surface rainfall data given location typically is substantially skewed. There are a number of precipitation process at work in the atmosphere, and few of them are well understood. The formal theory on sampling and estimating precipitation appears considerably deficient. Little systematic attention is given to nonsampling errors that always arise in utilizing any measurement system. Although the precipitation measurement problem is an old one, it continues to be one that is in need of systematic and careful attention. A brief history of the presently competing measurement technologies should aid us in understanding the problem inherent in this measurement task.

  5. A Modeling Perspective on Metacognition in Everyday Problem-Solving Situations.

    ERIC Educational Resources Information Center

    Hjalmarson, Margret

    This paper describes a models and modeling framework that has been applied to various areas in teaching, learning and problem solving. It examines the implications of that framework on metacognition and higher order thinking during everyday problem-solving situations that required teams of students to produce complex solutions in approximately 1-2…

  6. Saudi English-Major Undergraduates' Academic Writing Problems: A Taif University Perspective

    ERIC Educational Resources Information Center

    Al-Khairy, Mohamed Ali

    2013-01-01

    This study attempted to investigate Saudi English-major undergraduates studying at Taif University to identify a) the types of academic writing Saudi English-major undergraduates carry out at English departments, b) Saudi English-major undergraduates' writing problems, c) the reasons behind Saudi English-major undergraduates' writing problems and…

  7. Developing Physics Concepts through Hands-On Problem Solving: A Perspective on a Technological Project Design

    ERIC Educational Resources Information Center

    Hong, Jon-Chao; Chen, Mei-Yung; Wong, Ashley; Hsu, Tsui-Fang; Peng, Chih-Chi

    2012-01-01

    In a contest featuring hands-on projects, college students were required to design a simple crawling worm using planning, self-monitoring and self-evaluation processes to solve contradictive problems. To enhance the efficiency of problem solving, one needs to practice meta-cognition based on an application of related scientific concepts. The…

  8. Solving the Teacher Shortage Problem in Ghana: Critical Perspectives for Understanding the Issues

    ERIC Educational Resources Information Center

    Cobbold, Cosmas

    2015-01-01

    The problem of getting sufficient numbers of qualified teachers to staff classrooms is one of the most significant public policy issues facing many countries. In Ghana, the problem of teacher shortage has been a perennial one, necessitated by educational expansion as well as adverse socio-economic and political circumstances, and exacerbated by…

  9. Self-and Peer Perspectives on Pathological Personality Traits and Interpersonal Problems

    ERIC Educational Resources Information Center

    Clifton, Allan; Turkheimer, Eric; Oltmanns, Thomas F.

    2005-01-01

    This study compares the relationship between personality disorders and interpersonal problems as obtained by self-report and peer-report measures. Participants (N=393) were administered self-and peer-report versions of the Peer Inventory for Personality Disorder and the Inventory of Interpersonal Problems-64. Canonical analyses demonstrated…

  10. Cognitive Load for Configuration Comprehension in Computer-Supported Geometry Problem Solving: An Eye Movement Perspective

    ERIC Educational Resources Information Center

    Lin, John Jr-Hung; Lin, Sunny S. J.

    2014-01-01

    The present study investigated (a) whether the perceived cognitive load was different when geometry problems with various levels of configuration comprehension were solved and (b) whether eye movements in comprehending geometry problems showed sources of cognitive loads. In the first investigation, three characteristics of geometry configurations…

  11. Problem-Solving Mechanisms in L2 Communication: A Psycholinguistic Perspective.

    ERIC Educational Resources Information Center

    Dornyei, Zoltan; Kormos, Judit

    1998-01-01

    Investigates ways speakers manage problems and overcome difficulties in second language (L2) communication. Distinguishes four main sources of L2 communication problems; resource deficits; processing time pressure; perceived deficiencies in one's own language output; and perceived deficiencies in interlocutors performance. Adopts a…

  12. A Developmental Perspective on Peer Rejection, Deviant Peer Affiliation, and Conduct Problems Among Youth.

    PubMed

    Chen, Diane; Drabick, Deborah A G; Burgers, Darcy E

    2015-12-01

    Peer rejection and deviant peer affiliation are linked consistently to the development and maintenance of conduct problems. Two proposed models may account for longitudinal relations among these peer processes and conduct problems: the (a) sequential mediation model, in which peer rejection in childhood and deviant peer affiliation in adolescence mediate the link between early externalizing behaviors and more serious adolescent conduct problems; and (b) parallel process model, in which peer rejection and deviant peer affiliation are considered independent processes that operate simultaneously to increment risk for conduct problems. In this review, we evaluate theoretical models and evidence for associations among conduct problems and (a) peer rejection and (b) deviant peer affiliation. We then consider support for the sequential mediation and parallel process models. Next, we propose an integrated model incorporating both the sequential mediation and parallel process models. Future research directions and implications for prevention and intervention efforts are discussed.

  13. Quantum few-body problem with internal structure. I. Two-body problem

    SciTech Connect

    Kuperin, Yu.A.; Makarov, K.A.; Merkur'ev, S.P.; Motovilov, A.K.; Pavlov, B.S.

    1988-12-01

    The methods of the theory of extensions to an auxiliary Hilbert space are used to construct in the two-particle sector a scattering theory for particles possessing internal structure. The analytic properties of the amplitudes of resonance scattering and Green's functions corresponding to a class of singular energy-dependent interactions are investigated.

  14. Perspective: Role of structure prediction in materials discovery and design

    NASA Astrophysics Data System (ADS)

    Needs, Richard J.; Pickard, Chris J.

    2016-05-01

    Materials informatics owes much to bioinformatics and the Materials Genome Initiative has been inspired by the Human Genome Project. But there is more to bioinformatics than genomes, and the same is true for materials informatics. Here we describe the rapidly expanding role of searching for structures of materials using first-principles electronic-structure methods. Structure searching has played an important part in unraveling structures of dense hydrogen and in identifying the record-high-temperature superconducting component in hydrogen sulfide at high pressures. We suggest that first-principles structure searching has already demonstrated its ability to determine structures of a wide range of materials and that it will play a central and increasing part in materials discovery and design.

  15. Transfer from Structured to Open-Ended Problem Solving in a Computerized Metacognitive Environment

    ERIC Educational Resources Information Center

    Kapa, Esther

    2007-01-01

    A new computerized environment introducing a variety of metacognitive support mechanisms (MSMs) in different phases of the problem-solving process was designed to influence students' transfer from solving structured problems (near transfer) to solving open-ended problems (far transfer). Two hundred and thirty one students (aged 13-14 years) were…

  16. Using Jigsaw-Style Spectroscopy Problem-Solving to Elucidate Molecular Structure through Online Cooperative Learning

    ERIC Educational Resources Information Center

    Winschel, Grace A.; Everett, Renata K.; Coppola, Brian P.; Shultz, Ginger V.

    2015-01-01

    Cooperative learning was employed as an instructional approach to facilitate student development of spectroscopy problem solving skills. An interactive online environment was used as a framework to structure weekly discussions around spectroscopy problems outside of class. Weekly discussions consisted of modified jigsaw-style problem solving…

  17. Fusion proteins as alternate crystallization paths to difficult structure problems

    NASA Technical Reports Server (NTRS)

    Carter, Daniel C.; Rueker, Florian; Ho, Joseph X.; Lim, Kap; Keeling, Kim; Gilliland, Gary; Ji, Xinhua

    1994-01-01

    The three-dimensional structure of a peptide fusion product with glutathione transferase from Schistosoma japonicum (SjGST) has been solved by crystallographic methods to 2.5 A resolution. Peptides or proteins can be fused to SjGST and expressed in a plasmid for rapid synthesis in Escherichia coli. Fusion proteins created by this commercial method can be purified rapidly by chromatography on immobilized glutathione. The potential utility of using SjGST fusion proteins as alternate paths to the crystallization and structure determination of proteins is demonstrated.

  18. Typical Behavior of the Linear Programming Method for Combinatorial Optimization Problems: A Statistical-Mechanical Perspective

    NASA Astrophysics Data System (ADS)

    Takabe, Satoshi; Hukushima, Koji

    2014-04-01

    The typical behavior of the linear programming (LP) problem is studied as a relaxation of the minimum vertex cover problem, which is a type of integer programming (IP) problem. To deal with LP and IP using statistical mechanics, a lattice-gas model on the Erdös-Rényi random graphs is analyzed by a replica method. It is found that the LP optimal solution is typically equal to that given by IP below the critical average degree c*=e in the thermodynamic limit. The critical threshold for LP = IP extends the previous result c = 1, and coincides with the replica symmetry-breaking threshold of the IP.

  19. Relative Effects of Three Questioning Strategies in Ill-Structured, Small Group Problem Solving

    ERIC Educational Resources Information Center

    Byun, Hyunjung; Lee, Jung; Cerreto, Frank A.

    2014-01-01

    The purpose of this research is to investigate the relative effectiveness of using three different question-prompt strategies on promoting metacognitive skills and performance in ill-structured problem solving by examining the interplay between peer interaction and cognitive scaffolding. An ill-structured problem-solving task was given to three…

  20. Solving Ill-Structured Problems in Asynchronous Online Discussions: Built-in Scaffolds vs. No Scaffolds

    ERIC Educational Resources Information Center

    Ng, Connie Siew Ling; Cheung, Wing Sum; Hew, Khe Foon

    2010-01-01

    Solving ill-structured problems is regarded as an important learning outcome in education as it allows learners to apply theories learnt into real practice. An asynchronous online discussion, with extended time for reflection, is an appropriate learning environment to engage learners in solving ill-structured problems. However, scaffolds may be…

  1. Identifying and Measuring Ill-Structured Problem Formulation and Resolution in Online Asynchronous Discussions

    ERIC Educational Resources Information Center

    Murphy, Elizabeth

    2004-01-01

    This paper reports on a study involving the development and application of an instrument to identify and measure ill-structured problem formulation and resolution (PFR) in online asynchronous discussions (OADs). The instrument was developed by first determining PFR processes relevant to ill-structured problems in professional practice. The…

  2. Sequence and structural perspectives of bacterial β-stranded porins.

    PubMed

    Kumar, Abhishek; Bhandari, Anita; Krishnaswamy, Sankaran

    2015-01-01

    Porins are integral membrane proteins found in the outer membrane of bacteria, mitochondria and chloroplasts. Herein, we have reviewed sequence and structural understanding about bacterial porins. The first porin structure from Rhodobacter capsulatus at 1.8 Å resolution in 1991 till the recent structural advancement, coupled by immunological properties, diffusion and ion permeation has been taken into account In the later part, we have presented our computational analysis of conformational mobility in selected porins. Atomic B-factors (in crystal structures) are indicative of the degree of intrinsic mobility associated with residues and secondary structural elements of a particular protein. We have explored and extended the intrinsic motilities within porins using selected six porins structures. These six porins were collected from PDB and B-factor analyses were performed using AWK scripts. Distributions of residues and mobilities were characteristic of different porins. These distribution patterns follow the level of homology at the sequence and structural level. The inner walls constituting the trimer interface were found to be more rigid than the outer walls. These mobility differences are intrinsic structural components of these porins.

  3. Advances in understanding glycosyltransferases from a structural perspective

    PubMed Central

    Gloster, Tracey M

    2014-01-01

    Glycosyltransferases (GTs), the enzymes that catalyse glycosidic bond formation, create a diverse range of saccharides and glycoconjugates in nature. Understanding GTs at the molecular level, through structural and kinetic studies, is important for gaining insights into their function. In addition, this understanding can help identify those enzymes which are involved in diseases, or that could be engineered to synthesize biologically or medically relevant molecules. This review describes how structural data, obtained in the last 3–4 years, have contributed to our understanding of the mechanisms of action and specificity of GTs. Particular highlights include the structure of a bacterial oligosaccharyltransferase, which provides insights into N-linked glycosylation, the structure of the human O-GlcNAc transferase, and the structure of a bacterial integral membrane protein complex that catalyses the synthesis of cellulose, the most abundant organic molecule in the biosphere. PMID:25240227

  4. Theoretical Borderlands: Using Multiple Theoretical Perspectives to Challenge Inequitable Power Structures in Student Development Theory

    ERIC Educational Resources Information Center

    Abes, Elisa S.

    2009-01-01

    This article is an exploration of possibilities and methodological considerations for using multiple theoretical perspectives in research that challenges inequitable power structures in student development theory. Specifically, I explore methodological considerations when partnering queer theory and constructivism in research on lesbian identity…

  5. Cognitive Structures of the Gifted: Theoretical Perspectives, Factor Analysis, Triarchic Theories of Intelligence, and Insight Issues.

    ERIC Educational Resources Information Center

    Shaughnessy, Michael F.

    The paper reviews research on the cognitive structures of gifted students. Theories of R. Sternberg and his triarchic model of intelligence are described. Sternberg asserts that three processes appear to account for insight: selective encoding, selective combination, and selective comparison. H. Gardner's perspective citing six types of…

  6. Professional Orientation and Structural Components of Early Childhood Programs: A Social-Ecological Perspective.

    ERIC Educational Resources Information Center

    Jorde-Bloom, Paula

    A 1987 study, which involved 26 male and 805 female early childhood workers from 85 center-based programs in 20 states, was conducted to develop a social-ecological perspective on professional orientation and job satisfaction and on structural components of early childhood programs. Professional orientation is characterized by a person's emphasis…

  7. Atomic and Molecular Structure in Chemical Education: A Critical Analysis from Various Perspectives of Science Education.

    ERIC Educational Resources Information Center

    Tsaparlis, Georgios

    1997-01-01

    Provides a critical analysis of the role that atomic theory plays in the science curriculum from elementary through secondary school. Examines structural concepts from the perspective of the theory of meaningful learning, information processing theory, and the alternative conceptions movement. Contains 54 references. (DDR)

  8. A Structure-Agency Perspective on Young Children's Engagement in School Science: Carlos's Performance and Narrative

    ERIC Educational Resources Information Center

    Varelas, Maria; Tucker-Raymond, Eli; Richards, Kimberly

    2015-01-01

    Guided by sociological perspectives that view (young) children as agents who are shaped by and shape the structures of social systems in which they live, we studied forms that agency of young children from historically marginalized groups may take in science class when offered opportunities to engage in science in a variety of ways, how curricular…

  9. The Quality of High School Students' Problem Solving from an Expertise Development Perspective

    ERIC Educational Resources Information Center

    Elvira, Quincy; Imants, Jeroen; deMaeyer, Sven; Segers, Mien

    2015-01-01

    The ability to solve problems is a key skill and is essential to our day-to-day lives, at home, at school and at work. The present study explores the quality of managerial problem-solving of participants who are in secondary education. We studied 10th, 11th, and 12th graders following a business track in the Netherlands. Participants were asked to…

  10. Cosmological structure problem of the pre-big bang scenario

    NASA Astrophysics Data System (ADS)

    Hwang, Jai-chan

    1998-02-01

    We calculate the density and gravitational wave spectrums generated in a version of string cosmology termed pre-big bang scenario. The large scale structures are originated from quantum fluctuations of the metric and dilaton field during a pole-like inflation stage driven by a potential-less dilaton field realized in the low-energy effective action of string theory. The generated classical density field and the gravitational wave in the second horizon crossing epoch show tilted spectrums with n ⋍ 4 and n T ⋍ 3 , respectively. These differ from the observed spectrum of the large angular scale anisotropy of the cosmic microwave background radiation which supports scale invariant ones with n ⋍ 1 and n T ⋍ 0 . This suggests that the pre-big bang stage is not suitable for generating the present day observable large scale structures, and suggests the importance of investigating the quantum generation processes during stringy era with higher order quantum correction terms.

  11. [Rehabilitation after kidney transplantation: Old problems and new structures].

    PubMed

    Schiffer, L; Krautzig, S; Gerbig, D; Bintaro, P; Haller, H; Schiffer, M

    2016-01-01

    Kidney transplantation is currently the best therapeutic option for patients with end stage renal disease. Alternative treatment with hemo- or peritoneal dialysis is associated with higher comorbidities, higher morbidity/mortality, and reduced quality of life. Thus, a major aim in posttransplant care is to develop strategies to increase transplant survival and reduce known risk factors and comorbidities. In this overview, we propose a concept to include rehabilitation clinics in all aspects of the transplant process. This concept includes pretransplant care on the waiting list to prepare the patient for the transplant, the direct postoperative treatment phase, and repeated and risk adapted stays in rehabilitation clinics during long-term follow-up to address specific and individual problems.

  12. NASA Langley's Approach to the Sandia's Structural Dynamics Challenge Problem

    NASA Technical Reports Server (NTRS)

    Horta, Lucas G.; Kenny, Sean P.; Crespo, Luis G.; Elliott, Kenny B.

    2007-01-01

    The objective of this challenge is to develop a data-based probabilistic model of uncertainty to predict the behavior of subsystems (payloads) by themselves and while coupled to a primary (target) system. Although this type of analysis is routinely performed and representative of issues faced in real-world system design and integration, there are still several key technical challenges that must be addressed when analyzing uncertain interconnected systems. For example, one key technical challenge is related to the fact that there is limited data on target configurations. Moreover, it is typical to have multiple data sets from experiments conducted at the subsystem level, but often samples sizes are not sufficient to compute high confidence statistics. In this challenge problem additional constraints are placed as ground rules for the participants. One such rule is that mathematical models of the subsystem are limited to linear approximations of the nonlinear physics of the problem at hand. Also, participants are constrained to use these models and the multiple data sets to make predictions about the target system response under completely different input conditions. Our approach involved initially the screening of several different methods. Three of the ones considered are presented herein. The first one is based on the transformation of the modal data to an orthogonal space where the mean and covariance of the data are matched by the model. The other two approaches worked solutions in physical space where the uncertain parameter set is made of masses, stiffnesses and damping coefficients; one matches confidence intervals of low order moments of the statistics via optimization while the second one uses a Kernel density estimation approach. The paper will touch on all the approaches, lessons learned, validation 1 metrics and their comparison, data quantity restriction, and assumptions/limitations of each approach. Keywords: Probabilistic modeling, model validation

  13. A structural biology perspective on NMDA receptor pharmacology and function.

    PubMed

    Regan, Michael C; Romero-Hernandez, Annabel; Furukawa, Hiro

    2015-08-01

    N-methyld-aspartate receptors (NMDARs) belong to the large family of ionotropic glutamate receptors (iGluRs), which are critically involved in basic brain functions as well as multiple neurological diseases and disorders. The NMDARs are large heterotetrameric membrane protein complexes. The extensive extracellular domains recognize neurotransmitter ligands and allosteric compounds and translate the binding information to regulate activity of the transmembrane ion channel. Here, we review recent advances in the structural biology of NMDARs with a focus on pharmacology and function. Structural analysis of the isolated extracellular domains in combination with the intact heterotetrameric NMDAR structure provides important insights into how this sophisticated ligand-gated ion channel may function.

  14. An adaptive inverse iteration algorithm using interpolating multiwavelets for structural eigenvalue problems

    NASA Astrophysics Data System (ADS)

    Wang, Youming; Chen, Xuefeng; He, Zhengjia

    2011-02-01

    Structural eigenvalues have been broadly applied in modal analysis, damage detection, vibration control, etc. In this paper, the interpolating multiwavelets are custom designed based on stable completion method to solve structural eigenvalue problems. The operator-orthogonality of interpolating multiwavelets gives rise to highly sparse multilevel stiffness and mass matrices of structural eigenvalue problems and permits the incremental computation of the eigenvalue solution in an efficient manner. An adaptive inverse iteration algorithm using the interpolating multiwavelets is presented to solve structural eigenvalue problems. Numerical examples validate the accuracy and efficiency of the proposed algorithm.

  15. Perspectives for the structure-based design of acetylcholinesterase reactivators.

    PubMed

    Ochoa, Rodrigo; Rodriguez, Carlos A; Zuluaga, Andres F

    2016-07-01

    Rational design of active molecules through structure-based methods has been gaining adepts during the last decades due to the wider availability of protein structures, most of them conjugated with relevant ligands. Acetylcholinesterase (AChE) is a molecular target with a considerable amount of data related to its sequence and 3-dimensional structure. In addition, there are structural insights about the mechanism of action of the natural substrate and drugs used in Alzheimer's disease, organophosphorus compounds, among others. We looked for AChE structural data useful for in silico design of potential interacting molecules. In particular, we focused on information regarding the design of ligands aimed to reactivate AChE catalytic activity. The structures of 178 AChE were annotated and categorized on different subsets according to the nature of the ligand, source organisms and experimental details. We compared sequence homology among the active site from Torpedo californica, Mus musculus and Homo sapiens with the latter two species having the closest relationship (88.9% identity). In addition, the mechanism of organophosphorus binding and the design of effective reactivators are reviewed. A curated data collection obtained with information from several sources was included for researchers working on the field. Finally, a molecular dynamics simulation with human AChE indicated that the catalytic pocket volume stabilizes around 600 Å(3), providing additional clues for drug design. PMID:27450771

  16. Illuminating the dark matter of social neuroscience: Considering the problem of social interaction from philosophical, psychological, and neuroscientific perspectives

    PubMed Central

    Przyrembel, Marisa; Smallwood, Jonathan; Pauen, Michael; Singer, Tania

    2012-01-01

    Successful human social interaction depends on our capacity to understand other people's mental states and to anticipate how they will react to our actions. Despite its importance to the human condition, the exact mechanisms underlying our ability to understand another's actions, feelings, and thoughts are still a matter of conjecture. Here, we consider this problem from philosophical, psychological, and neuroscientific perspectives. In a critical review, we demonstrate that attempts to draw parallels across these complementary disciplines is premature: The second-person perspective does not map directly to Interaction or Simulation theories, online social cognition, or shared neural network accounts underlying action observation or empathy. Nor does the third-person perspective map onto Theory-Theory (TT), offline social cognition, or the neural networks that support Theory of Mind (ToM). Moreover, we argue that important qualities of social interaction emerge through the reciprocal interplay of two independent agents whose unpredictable behavior requires that models of their partner's internal state be continually updated. This analysis draws attention to the need for paradigms in social neuroscience that allow two individuals to interact in a spontaneous and natural manner and to adapt their behavior and cognitions in a response contingent fashion due to the inherent unpredictability in another person's behavior. Even if such paradigms were implemented, it is possible that the specific neural correlates supporting such reciprocal interaction would not reflect computation unique to social interaction but rather the use of basic cognitive and emotional processes combined in a unique manner. Finally, we argue that given the crucial role of social interaction in human evolution, ontogeny, and every-day social life, a more theoretically and methodologically nuanced approach to the study of real social interaction will nevertheless help the field of social cognition

  17. PREDICTORS OF EMOTIONAL AND BEHAVIORAL PROBLEMS IN 1-YEAR-OLD CHILDREN: A LONGITUDINAL PERSPECTIVE.

    PubMed

    Sirvinskiene, Giedre; Zemaitiene, Nida; Jusiene, Roma; Markuniene, Egle

    2016-07-01

    Emotional and behavioral problems at an early age can reasonably be considered a high-risk factor for later mental health disorders. The aim of the article is to reveal predictive factors of 1½-year-old children's emotional and behavioral problems. The study was a part of a prospective birth-cohort study. The study sample consisted of 172 full-term infants (born during Gestational Weeks 37-42) and their mothers. Emotional and behavioral problems at the age of 1½ years were measured using the Child Behavior Checklist for Ages 1½-5 (T. Achenbach & L. Rescorla, 2000), which was completed by mothers. Emotional and behavioral problems at age of 1½ years were more prevalent in infants born via cesarean section, as compared to infants born vaginally without administration of medication. Newborns' suboptimal functioning after birth, complicated emotional acceptance of pregnancy, a couple's nonsatisfactory relationship during pregnancy, maternal distress during pregnancy and in the first months after childbirth, and inflexible and parent-oriented attitudes toward infant-rearing also predicted children's emotional and behavioral problems independent of sociodemographic factors. Results suggest that biomedical and psychosocial factors which manifest themselves in the prenatal and perinatal periods can have associations with later infant and child mental health. PMID:27336695

  18. PREDICTORS OF EMOTIONAL AND BEHAVIORAL PROBLEMS IN 1-YEAR-OLD CHILDREN: A LONGITUDINAL PERSPECTIVE.

    PubMed

    Sirvinskiene, Giedre; Zemaitiene, Nida; Jusiene, Roma; Markuniene, Egle

    2016-07-01

    Emotional and behavioral problems at an early age can reasonably be considered a high-risk factor for later mental health disorders. The aim of the article is to reveal predictive factors of 1½-year-old children's emotional and behavioral problems. The study was a part of a prospective birth-cohort study. The study sample consisted of 172 full-term infants (born during Gestational Weeks 37-42) and their mothers. Emotional and behavioral problems at the age of 1½ years were measured using the Child Behavior Checklist for Ages 1½-5 (T. Achenbach & L. Rescorla, 2000), which was completed by mothers. Emotional and behavioral problems at age of 1½ years were more prevalent in infants born via cesarean section, as compared to infants born vaginally without administration of medication. Newborns' suboptimal functioning after birth, complicated emotional acceptance of pregnancy, a couple's nonsatisfactory relationship during pregnancy, maternal distress during pregnancy and in the first months after childbirth, and inflexible and parent-oriented attitudes toward infant-rearing also predicted children's emotional and behavioral problems independent of sociodemographic factors. Results suggest that biomedical and psychosocial factors which manifest themselves in the prenatal and perinatal periods can have associations with later infant and child mental health.

  19. Structural problems of the Brooks Range ophiolite, Alaska

    SciTech Connect

    Harris, R.A.; Bickerstaff, D. . Dept. of Geology); Stone, D.B. . Geophysical Inst.)

    1993-04-01

    Structural and paleogeographic restorations of the Brooks Range ophiolite (hereafter BRO) and other associated mafic and ultramafic bodies of N. Alaska are difficult because of ambiguous relations between sheeted dikes, cover sediments, and steep NW and SE dipping magmatic flow fabrics. Paleomagnetically enhanced structural studies at Misheguk, Avan, and Siniktanneyak Mountains provide new constraints for the initial dip and sequence of deformation for various structural features of the BRO. The angle between magmatic layers near the petrologic moho and the paleomagnetic inclination of these layers is 50--63[degree] at Misheguk. High level gabbro layers that are disrupted by syn- and post-cooling intrusions display a greater variation. Assuming that the characteristic magnetization is primary, and that the primary inclination was > 80[degree], magmatic layers and the moho had initial dips from 17--40[degree]. These layers now dip 40--70[degree]SE suggesting some post-magmatic tilt. The variation of inclinations with depth in the ophiolite suggest that high level gabbro has tilted most. Sheeted dikes are documented at the Maiyumerak and Siniktanneyak ophiolite bodies. At both locations the dikes dip steeply and strike NE-SW. Sedimentary and volcanic flow layers associated with the dikes have the same strike and dip 0--30[degree]. Parallelism between various planar features throughout the BRO indicates that rotations about a vertical axis are either uniform throughout the ophiolite belt or negligible. Assuming the later, the BRO may represent a linear zone of SSZ magmatism that was oriented NE-SW prior to collision. Post-emplacement long wavelength folding of the ophiolite lid can account for its variation in facing direction and some steepening of magmatic layers.

  20. The extension problem for partial Boolean structures in quantum mechanics

    NASA Astrophysics Data System (ADS)

    Budroni, Costantino; Morchio, Giovanni

    2010-12-01

    Alternative partial Boolean structures, implicit in the discussion of classical representability of sets of quantum mechanical predictions, are characterized, with definite general conclusions on the equivalence of the approaches going back to Bell and Kochen-Specker. An algebraic approach is presented, allowing for a discussion of partial classical extension, amounting to reduction of the "number of contexts," classical representability arising as a special case. As a result, known techniques are generalized and some of the associated computational difficulties overcome. The implications on the discussion of Boole-Bell inequalities are indicated.

  1. Self- and Peer Perspectives on Pathological Personality Traits and Interpersonal Problems

    PubMed Central

    Clifton, Allan; Turkheimer, Eric; Oltmanns, Thomas F.

    2015-01-01

    This study compares the relationship between personality disorders and interpersonal problems as obtained by self-report and peer-report measures. Participants (N = 393) were administered self- and peer-report versions of the Peer Inventory for Personality Disorder and the Inventory of Interpersonal Problems–64. Canonical analyses demonstrated similar relationships between personality disorder features and interpersonal problems as measured by either self or peer. Analyses between self and peer found little shared variance across sources, indicating a large method variance. Results indicate that although similar constructs are identified by self and peers in their understanding of personality pathology and associated interpersonal problems, self-report information overlaps very little with information obtained from peers, underscoring the importance of obtaining multiple sources of information. PMID:16029099

  2. Problems of providing services to people affected by HIV/AIDS: service providers and recipients perspectives.

    PubMed

    Moradi, G; Mohraz, M; Gouya, M M; Dejman, M; Alinaghi, S S; Rahmani, K; Malekafzali-Ardakani, H

    2015-02-25

    This qualitative study aimed to identify the health-care problems of people living with HIV (PLHIV) in 2 large cities: Tehran and Kermanshah. Two main groups of stakeholders - service providers (policy-makers, managers, physicians and counsellors) and service recipients (PLHIV and their relatives) - participated in focus group discussions and in-depth interviews. We identified 24 themes covering the major health problems of PLHIV, including: incomplete and inadequate coverage of health-care services; patients' substance abuse; patients' fear of stigma; occupational burnout of certain service providers; patients' dissatisfaction with some of the services provided by counselling centres/clinics; medical staff's failure to observe confidentiality; and patients' lack of access to required specialized services. The problems and needs identified can inform the design and implementation of health programmes in our country and elsewhere in the Eastern Mediterranean Region.

  3. Health promotion teams' effectiveness: a structural perspective from Israel.

    PubMed

    Drach-Zahavy, Anat; Baron-Epel, Orna

    2006-09-01

    This study addressed the question of how to structure coalitions in order to increase their engagement in multiple strategies for health promotion and consequently to improve their effectiveness. Three structural variables were chosen: (i) coalition's heterogeneity, captured by the professional diversity of its members; (ii) coalition's configuration, defined as the way members were involved in the coalition: full- or part-cycle membership, full- or part-time assignment, and core or peripheral membership; and (iii) coalition's contractual collaborations with external professionals. A large non-profit network of community centers served as the setting for this study. The sample consisted of 37 coordinators of local coalitions for health promotion in Israel. The study's design was a cross-sectional survey. Data were collected by a multimethod (semistructured interviews, self reported questionnaires and administrative data) approach. Effectiveness was assessed by a self-report questionnaire administrated to coalition coordinators. Engagements in multistrategies as well as structural variables were measured by semistructured interviews with coalition coordinators. Results demonstrated that while a homogeneous, bounded structure seemed to promote the implementation of health education programs, a more flexible coalition configuration with frequent use of professionals contributed more to working by multiple strategies and improved coalition's effectiveness. In addition, the use of external professionals promoted action for a healthier environment, but did not add to empowering the community. The results contribute to shifting the conception of a coalition as a tightly bounded, well-defined, stable entity to that of a more fluid and permeable structure interacting with an external environment. These findings highlight the importance of incorporating structural considerations into the management of coalitions and are discussed in light of the potential costs and benefits

  4. Narcissism as a motivational structure: the problem of personal significance.

    PubMed

    Shaw, J A

    2000-01-01

    An understanding of individual life is contingent on understanding not only man's traditional motivations but also the individual strategy for resolving the problem of personal insignificance. Man's sense of personal insignificance comes from two primary experiences: (a) the developmental experience with its increasing awareness of separation and loss, transience, and the sense of lost felt perfectibility; and (b) the increasing cognitive awareness of the immutable laws of biology and the limitations of the self and others in which idealization gives way to painful reality. Each individual seeks narcissistic reparation through the elaboration of a personal narrative or myth, a story, which gives one's life a feeling of personal significance, meaning, and purpose. What is relevant is not the presence or absence of a myth or personal narrative but within which myth one chooses to live one's life. Myths are not explanations rooted in scientific evidence but rather are belief systems lived as if they were truths. Myths provide the individual with a personal sense of identity, and they confirm and affirm memberships in a group or community, and provide guidelines and an idealized set of behaviors within which to operate. Lastly, they may endorse an explanation for the mysterious universe. Three motivational strategies in which the aim is to create a personal myth or personal narrative that ensures a sense of personal significance are described in this article: (a) transcendental or spiritual myths, (b) group or interpersonal myths, and (c) humanistic or personal myths.

  5. [A historical-epistemological perspective of the ontological problem of Positivism. Positivism and psychiatry].

    PubMed

    Fantin, Juan Carlos

    2005-01-01

    The present article reviews epistemological problems related to the philosophical and scientific current known as Positivism. The revision begins with the study of the historical period during which the Logical Positivism emerges (early in the decade of 1920); and finishes with the analysis of its influence on psychiatry and its relation with other epistemological currents in the same period. The article reviews the historical and epistemological outlook at te beginning of the XX th century, when the problem of language became ontologically outstanding. The question of language remains important in the present discussions. PMID:16314903

  6. Synthesis, spectroscopic and structural perspective of new ferrocenyl amides

    NASA Astrophysics Data System (ADS)

    Etter, Martin; Nigar, Asifa; Ali, Naveed Zafar; Akhter, Zareen; Dinnebier, Robert E.

    2016-05-01

    Two new ferrocene derivatives with amide linkages were synthesized by the condensation of 4-ferrocenylaniline with n-alkyl acid chloride derivatives as pristine orange solids in good yields. FTIR and 1H/13C NMR studies have confirmed the basic structure of the molecules with the involvement of intermolecular H-bonding, which together with the ferrocene-like packing ensures the stability of the crystal structure. Crystal structures for both compounds were solved by Rietveld refinements of high resolution X-ray powder diffraction data. The XRD results show that both compounds crystallize in the monoclinic space group P21/c. The primary feature of the crystal structure is a double layer of ferrocenyl groups stretched out in the b-c -plane perpendicular to the a-axis, with packing of the ferrocenyl groups occurring in a manner similar to that of pure ferrocene. Despite the close structural similarity, both compounds differ in the optimized geometry of respective Ferrocene conformers. The Cp rings are eclipsed for one Ferrocene conformer and close to staggered for the other, owing to the low energy barrier for the rotation of a cyclopentadienyl ring relative to the rest of the molecule.

  7. Manipulation of logical structure of chemistry problems and its effect on student performance

    NASA Astrophysics Data System (ADS)

    Niaz, Mansoor; Robinson, William R.

    It has been shown previously that manipulation of the M demand (amount of information needed for processing) of chemistry problems affects student performance, which suggests that manipulation of logical structure of chemistry problems could also lead to significant changes in performance. The objective of this study is to investigate the following: Given the opportunity for training, what is the effect of increasing (manipulation) the complexity of logical structure of chemistry problems on student performance, and to what extent can cognitive variables explain changes in performance. Results obtained show that (a) even a small increase in the logical structure of a problem can change the role of cognitive variables (mental capacity and formal reasoning) to the extent that increase in logical complexity outweighs the advantage students may have gained through training on a similar problem; (b) the use of algorithms and training on particular types of chemistry problems could lead to a situation in which formal reasoning is the only cognitive variable that explains variance in performance significantly; and (c) after having solved very similar problems on two different occasions with improving performance, the improvement is not retained if the logical structure of a third problem increases considerably. It is concluded that when dealing with significant changes in logical complexity of chemistry problems, developmental level of students is the most consistent predictor of success. A model for the qualitative analysis of logical complexity of chemistry problems is presented.

  8. A Structural Perspective on the Regulation of the EGF Receptor

    PubMed Central

    Kovacs, Erika; Zorn, Julie Anne; Huang, Yongjian; Barros, Tiago; Kuriyan, John

    2015-01-01

    The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase that plays a critical role in the pathogenesis of many cancers. EGFR is unique in that its ligand-induced dimerization is established solely by contacts between regions of the receptor that are occluded within the monomeric, unliganded state. Activation of EGFR depends on the formation of an asymmetric dimer of the intracellular module of two receptor molecules, a configuration observed in crystal structures of the EGFR kinase domain in the active state. Coupling between the extracellular and intracellular modules is achieved by a switch between alternative geometries of the transmembrane and juxtamembrane segments within the receptor dimer. As the structure of the full-length receptor is yet to be determined, here we review recent structural studies on isolated modules of EGFR and molecular dynamics simulations that have provided much of our current understanding of its signaling mechanism, including how its regulation is compromised by oncogenic mutations. PMID:25621509

  9. Varying Fine-Structure Constant and the Cosmological Constant Problem

    NASA Astrophysics Data System (ADS)

    Fujii, Yasunori

    We start with a brief account of the latest analysis of the Oklo phenomenon providing the still most stringent constraint on time variability of the fine-structure constant α. Comparing this with the recent result from the measurement of distant QSO's appears to indicate a non-uniform time-dependence, which we argue to be related to another recent finding of the accelerating universe. This view is implemented in terms of the scalar-tensor theory, applied specifically to the small but nonzero cosmological constant. Our detailed calculation shows that these two phenomena can be understood in terms of a common origin, a particular behavior of the scalar field, dilaton. We also sketch how this theoretical approach makes it appropriate to revisit non-Newtonian gravity featuring small violation of Weak Equivalence Principle at medium distances.

  10. ESP Teaching at the Institutions of Higher Education in Modern Russia: Problems and Perspectives

    ERIC Educational Resources Information Center

    Prudnikova, Nadezhda

    2013-01-01

    The author analyses ESP teaching at the institutions of higher education in modern Russia, explains the main problems and suggests the ways of their solving, details the quality control system of the students' progress improvement, presents the complex approach to interactive ESP teaching and views it as an integral part of up-to-date…

  11. Students' Perspectives on Problem-Based Learning in a Transitional Doctorate of Physical Therapy Program

    ERIC Educational Resources Information Center

    Larin, Helene M.; Buccieri, Kathleen M.; Wessel, Jean

    2010-01-01

    Doctor of physical therapy (DPT) graduates are expected to be competent in professional behaviors, communication, critical inquiry, clinical decision making, and evidence-based practice. The purpose of this qualitative study was to describe the experience of students enrolled in a single, problem-based learning (PBL) course within a conventional…

  12. Children's Comprehension Problems in Oral and Written Language: A Cognitive Perspective. Challenges in Language and Literacy

    ERIC Educational Resources Information Center

    Cain, Kate, Ed.; Oakhill, Jane, Ed.

    2007-01-01

    Comprehension is the ultimate aim of reading and listening. How do children develop the ability to comprehend written and spoken language, and what can be done to help those who are having difficulties? This book presents cutting-edge research on comprehension problems experienced by children without any formal diagnosis as well as those with…

  13. Age and Gender Differences in Coping Style across Various Problems: Omani Adolescents' Perspective

    ERIC Educational Resources Information Center

    Al-Bahrani, Muna; Aldhafri, Said; Alkharusi, Hussain; Kazem, Ali; Alzubiadi, Abdulqawi

    2013-01-01

    This study examines adolescents' coping styles, with relation to their gender and age and level, of six types of problems. The participants were 1843 adolescents (51.7% female and 48.3% male) from the Sultanate of Oman with a mean age of 15.75. Two scales examining general adaptive and maladaptive coping styles and levels of school, economic,…

  14. A Modeling Perspective on the Teaching and Learning of Mathematical Problem Solving

    ERIC Educational Resources Information Center

    Mousoulides, Nicholas G.; Christou, Constantinos; Sriraman, Bharath

    2008-01-01

    This study analyzed the processes used by students when engaged in modeling activities and examined how students' abilities to solve modeling problems changed over time. Two student populations, one experimental and one control group, participated in the study. To examine students' modeling processes, the experimental group participated in an…

  15. Facilitators' Perspectives of the Factors That Affect the Effectiveness of Problem-Based Learning Process

    ERIC Educational Resources Information Center

    Chan, Cecilia K. Y.

    2016-01-01

    Many educational researchers have established problem-based learning (PBL) as a total approach to education--both a product and a process--from a pedagogical instructional strategy to skills development to assessment. This study provides qualitative evidences from educational practitioners in various professional disciplines, namely, Medicine,…

  16. Do Students Trust in Mathematics or Intuition during Physics Problem Solving? An Epistemic Game Perspective

    ERIC Educational Resources Information Center

    Yavuz, Ahmet

    2015-01-01

    This study aims to investigate (1) students' trust in mathematics calculation versus intuition in a physics problem solving and (2) whether this trust is related to achievement in physics in the context of epistemic game theoretical framework. To achieve this research objective, paper-pencil and interview sessions were conducted. A paper-pencil…

  17. The Effects of Teaching Programming via Scratch on Problem Solving Skills: A Discussion from Learners' Perspective

    ERIC Educational Resources Information Center

    Kalelioglu, Filiz; Gülbahar, Yasemin

    2014-01-01

    Computer programming is perceived as an important competence for the development of problem solving skills in addition to logical reasoning. Hence, its integration throughout all educational levels, as well as the early ages, is considered valuable and research studies are carried out to explore the phenomenon in more detail. In light of these…

  18. Human IgG4: a structural perspective

    PubMed Central

    Davies, Anna M; Sutton, Brian J

    2015-01-01

    IgG4, the least represented human IgG subclass in serum, is an intriguing antibody with unique biological properties, such as the ability to undergo Fab-arm exchange and limit immune complex formation. The lack of effector functions, such as antibody-dependent cell-mediated cytotoxicity and complement-dependent cytotoxicity, is desirable for therapeutic purposes. IgG4 plays a protective role in allergy by acting as a blocking antibody, and inhibiting mast cell degranulation, but a deleterious role in malignant melanoma, by impeding IgG1-mediated anti-tumor immunity. These findings highlight the importance of understanding the interaction between IgG4 and Fcγ receptors. Despite a wealth of structural information for the IgG1 subclass, including complexes with Fcγ receptors, and structures for intact antibodies, high-resolution crystal structures were not reported for IgG4-Fc until recently. Here, we highlight some of the biological properties of human IgG4, and review the recent crystal structures of IgG4-Fc. We discuss the unexpected conformations adopted by functionally important Cγ2 domain loops, and speculate about potential implications for the interaction between IgG4 and FcγRs. PMID:26497518

  19. Research Articles in Applied Linguistics: Structures from a Functional Perspective

    ERIC Educational Resources Information Center

    Ruiying, Yang; Allison, Desmond

    2004-01-01

    This paper presents the main lines of a genre analysis of the macro-structures of research articles (RAs) in applied linguistics, an area that deserves more attention both for pedagogic and research reasons. The analysis is based upon a detailed study of a corpus of 40 RAs, selected as random sets of 10 drawn from four leading journals in the…

  20. Perspectives on "Bakke": Equal Protection, Procedural Fairness, or Structural Justice?

    ERIC Educational Resources Information Center

    Tribe, Laurence H.

    1979-01-01

    The "Bakke" case is examined for what it has to say regarding first the area of equal protection, then the idea of procedural fairness as distinct from accuracy of result, and finally the notion of structural justice. Available from Harvard Law Review, Harvard Law Review Association, Gannett House, Cambridge, Massachusetts 02138; sc $5.50.…

  1. The Structure of Women's Employment in Comparative Perspective

    ERIC Educational Resources Information Center

    Pettit, Becky; Hook, Jennifer Lynn

    2005-01-01

    In this paper we analyze social survey data from 19 countries using multi-level modeling methods in an effort to synthesize structural and institutional accounts for variation in women's employment. Observed demographic characteristics show much consistency in their relationship to women's employment across countries, yet there is significant…

  2. Normative and Structural Perspectives on Age in a Work Organization.

    ERIC Educational Resources Information Center

    Lawrence, Barbara S.

    Age grading, the differentiation of social groups by members' age judgments, is widely regarded to be a universal aspect of social life. Most studies have examined age structurally (demographically), rather than normatively (modally). This study presents survey data measuring employees' age judgments of managerial careers collected from an…

  3. A Historical Perspective and Overview of Protein Structure Prediction

    NASA Astrophysics Data System (ADS)

    Wooley, John C.; Ye, Yuzhen

    Carrying on many different biological functions, proteins are all composed of one or more polypeptide chains, each containing from several to hundreds or even thousands of the 20 amino acids. During the 1950s at the dawn of modern biochemistry, an essential question for biochemists was to understand the structure and function of these polypeptide chains. The sequences of protein, also referred to as their primary structures, determine the different chemical properties for different proteins, and thus continue to captivate much of the attention of biochemists. As an early step in characterizing protein chemistry, British biochemist Frederick Sanger designed an experimental method to identify the sequence of insulin (Sanger et al., 1955). He became the first person to obtain the primary structure of a protein and in 1958 won his first Nobel Price in Chemistry. This important progress in sequencing did not answer the question of whether a single (individual) protein has a distinctive shape in three dimensions (3D), and if so, what factors determine its 3D architecture. However, during the period when Sanger was studying the primary structure of proteins, American biochemist Christian Anfinsen observed that the active polypeptide chain of a model protein, bovine pancreatic ribonuclease (RNase), could fold spontaneously into a unique 3D structure, which was later called native conformation of the protein (Anfinsen et al., 1954). Anfinsen also studied the refolding of RNase enzyme and observed that an enzyme unfolded under extreme chemical environment could refold spontaneously back into its native conformation upon changing the environment back to natural conditions (Anfinsen et al., 1961). By 1962, Anfinsen had developed his theory of protein folding (which was summarized in his 1972 Nobel acceptance speech): "The native conformation is determined by the totality of interatomic interactions and hence, by the amino acid sequence, in a given environment."

  4. The effect of neighborhood structures on tabu search algorithm in solving university course timetabling problem

    NASA Astrophysics Data System (ADS)

    Shakir, Ali; AL-Khateeb, Belal; Shaker, Khalid; Jalab, Hamid A.

    2014-12-01

    The design of course timetables for academic institutions is a very difficult job due to the huge number of possible feasible timetables with respect to the problem size. This process contains lots of constraints that must be taken into account and a large search space to be explored, even if the size of the problem input is not significantly large. Different heuristic approaches have been proposed in the literature in order to solve this kind of problem. One of the efficient solution methods for this problem is tabu search. Different neighborhood structures based on different types of move have been defined in studies using tabu search. In this paper, different neighborhood structures on the operation of tabu search are examined. The performance of different neighborhood structures is tested over eleven benchmark datasets. The obtained results of every neighborhood structures are compared with each other. Results obtained showed the disparity between each neighborhood structures and another in terms of penalty cost.

  5. Gauging the Potential of Socially Critical Environmental Education (EE): Examining Local Environmental Problems through Children's Perspective

    ERIC Educational Resources Information Center

    Tsoubaris, Dimitris; Georgopoulos, Aleksandros

    2013-01-01

    The objective of this qualitative research work is to detect the needs, aspirations and feelings of pupils experiencing local environmental problems and elaborate them through the prism of a socially critical educational approach. Semi-structured focus group interviews are used as a research method applied to four primary schools located near…

  6. Predicting the future from the past: An old problem from a modern perspective

    NASA Astrophysics Data System (ADS)

    Cecconi, F.; Cencini, M.; Falcioni, M.; Vulpiani, A.

    2012-11-01

    The idea of predicting the future from the knowledge of the past is quite natural, even when dealing with systems whose equations of motion are not known. This long-standing issue is revisited in the light of modern ergodic theory of dynamical systems and becomes particularly interesting from a pedagogical perspective due to its close link with Poincaré's recurrence. Using such a connection, a very general result of ergodic theory—Kac's lemma—can be used to establish the intrinsic limitations to the possibility of predicting the future from the past. In spite of a naive expectation, predictability is hindered more by the effective number of degrees of freedom of a system than by the presence of chaos. If the effective number of degrees of freedom becomes large enough, whether the system is chaotic or not, predictions turn out to be practically impossible. The discussion of these issues is illustrated with the help of the numerical study of simple models.

  7. Perspective: Closing the Dietary Fiber Gap: An Ancient Solution for a 21st Century Problem.

    PubMed

    Thompson, Henry J; Brick, Mark A

    2016-07-01

    An important gap exists between the daily amounts of fiber recommended in the human diet (28-42 g/d) and that which is actually consumed (median intake, 12-14 g/d). In fact, <5% of Americans meet the recommended intake for dietary fiber, and the magnitude of the gap is large, approximately a 50-70% shortfall. Because considerable evidence indicates that dietary fiber affects normal physiologic function and the onset of chronic diseases and their progression, the fiber gap represents an opportune target at which dietary interventions can be directed. This perspective considers whether a scientific basis exists for the current lack of emphasis on pulse crops, that is, grain legumes (common bean, chickpea, lentils, and garden pea) as a concentrated, inexpensive, and widely available source of dietary fiber. Attention is directed to this topic because the fiber gap has existed for decades with little improvement despite nutrition labeling, consumer education about the value of whole-grain cereal crop-based products, and the introduction of many fiber-enriched foods. The time is long overdue to identify additional approaches that have the potential to close the dietary fiber gap. To this end, the potential role of pulse crops in remediating this gap is examined. PMID:27422499

  8. Fetal alcohol syndrome: new perspectives for an ancient and underestimated problem.

    PubMed

    de Sanctis, Luisa; Memo, Luigi; Pichini, Simona; Tarani, Luigi; Vagnarelli, Federica

    2011-10-01

    The knowledge of the dangers of alcohol consumption during pregnancy isn't indeed a new issue, but the recent evidences of ethyl-glucuronide and ethyl-sulfate in meconium as novel biomarkers of prenatal ethanol exposure open new perspectives for the early diagnosis of the alcohol-related birth defects. This is crucial for a better developmental outcome of the affected patients and for preventing additional cases in at risk families. The fetal alcohol syndrome is not a single entity but represents the most severe form of a spectrum of disorders, including distinctive craniofacial alterations, stunted growth and behavioral abnormalities, caused by complex gene-environment interactions. FAS must always be a diagnosis of exclusion and have to be differentiated from many conditions caused by other embryotoxin agents and genetic syndromes that share some phenotypic features. Even if the first trimester is considered the most vulnerable period, nowadays is known that a fetal damage might occur throughout all gestation. Since ethanol consumption is constantly increasing among young women, a substantial amount of work has to be made to implement the knowledge on alcohol fetal effects among women of childbearing age; moreover, awareness and training among professionals in the health care system might play a critical role in the early diagnosis of these serious conditions.

  9. Contraceptive services for adolescents in Latin America: facts, problems and perspectives.

    PubMed

    Pons, J E

    1999-12-01

    This review presents facts about sexual and contraceptive behavior of Latin American adolescents, analyzes barriers to contraception, and summarizes present perspectives. Between 13 and 30% of Latin American adolescent women live in union before their 20th birthday and between 46 and 63% have had sexual relations. The prevalence of contraceptive use among adolescents at risk of pregnancy remains very low. The pill is the best known contraceptive method. When sexual activity becomes a permanent practice, contraceptive use increases but remains low. Barriers to contraception can be identified as: (1) arising from adolescents themselves (moral objections, alleged medical reasons, lack of confidence in adults and in the health system, promiscuity; (2) arising from the sexual partner (partner's opposition, masculine irresponsibility); (3) arising from adults (moral objections, fear of sex education, adult control and power of decision-making); (4) arising from the health system (inappropriateness of services, regulatory barriers, gender inequality); (5) arising from health professionals (medical barriers to contraceptive use, discomfort with sexual matters); (6) arising from the educational system (educational failure, teachers' reluctance); and (7) arising from other social agents (religious opposition, media ambivalent messages, fund restraints). There have been improvements in recent years, including the achievements of groups working for and with adolescents, and the support from distinguished personalities.

  10. Evolutionary perspectives of telomerase RNA structure and function

    PubMed Central

    Podlevsky, Joshua D.; Chen, Julian J.-L.

    2016-01-01

    ABSTRACT Telomerase is the eukaryotic solution to the ‘end-replication problem’ of linear chromosomes by synthesising the highly repetitive DNA constituent of telomeres, the nucleoprotein cap that protects chromosome termini. Functioning as a ribonucleoprotein (RNP) enzyme, telomerase is minimally composed of the highly conserved catalytic telomerase reverse transcriptase (TERT) and essential telomerase RNA (TR) component. Beyond merely providing the template for telomeric DNA synthesis, TR is an innate telomerase component and directly facilitates enzymatic function. TR accomplishes this by having evolved structural elements for stable assembly with the TERT protein and the regulation of the telomerase catalytic cycle. Despite its prominence and prevalence, TR has profoundly diverged in length, sequence, and biogenesis pathway among distinct evolutionary lineages. This diversity has generated numerous structural and mechanistic solutions for ensuring proper RNP formation and high fidelity telomeric DNA synthesis. Telomerase provides unique insights into RNA and protein coevolution within RNP enzymes. PMID:27359343

  11. Strengths and weaknesses of Problem Based Learning from the professional perspective of registered nurses 1

    PubMed Central

    Cónsul-Giribet, María; Medina-Moya, José Luis

    2014-01-01

    OBJECTIVE: to identify competency strengths and weaknesses as perceived by nursing professionals who graduated with a integrated curriculum and competency-based through Problem Based Learning in small groups. METHOD: an intrinsic case study method was used, which analyzes this innovation through former students (from the first class) with three years of professional experience. The data were collected through a questionnaire and discussion groups. RESULTS: the results show that their competency level is valued in a very satisfactory manner. This level paradoxically contrasts with the lack of theoretical knowledge they perceived at the end of their education, when they started working in clinical practice. CONCLUSIONS: the teaching strategy was key to motivate an in-depth study and arouse the desire to know. In addition, Problem Based Learning favors and reinforces the decision to learn, which is that necessary in the course of professional life. PMID:25493666

  12. Buckling of structures with uncertain imperfections - Personal perspective

    NASA Technical Reports Server (NTRS)

    Elishakoff, Isaac

    1998-01-01

    The previous review on stochastic buckling of structures was written by Amazigo in 1976. This review summarizes some of the developments which took place in recent two decades. A brief overview is given of the effect on uncertainty in the initial geometric imperfections, elastic moduli, applied forces, and thickness variation. For the benefit of the thinking reader, the review has a critical nature. It should be noted that this manuscript has yet to be completed.

  13. A Structural Perspective on the Dynamics of Kinesin Motors

    PubMed Central

    Hyeon, Changbong; Onuchic, José N.

    2011-01-01

    Despite significant fluctuation under thermal noise, biological machines in cells perform their tasks with exquisite precision. Using molecular simulation of a coarse-grained model and theoretical arguments, we envisaged how kinesin, a prototype of biological machines, generates force and regulates its dynamics to sustain persistent motor action. A structure-based model, which can be versatile in adapting its structure to external stresses while maintaining its native fold, was employed to account for several features of kinesin dynamics along the biochemical cycle. This analysis complements our current understandings of kinesin dynamics and connections to experiments. We propose a thermodynamic cycle for kinesin that emphasizes the mechanical and regulatory role of the neck linker and clarify issues related to the motor directionality, and the difference between the external stalling force and the internal tension responsible for the head-head coordination. The comparison between the thermodynamic cycle of kinesin and macroscopic heat engines highlights the importance of structural change as the source of work production in biomolecular machines. PMID:22261064

  14. Dietary lipids from an evolutionary perspective: sources, structures and functions.

    PubMed

    German, J Bruce

    2011-04-01

    Lipids are a complex group of biomolecules whose precise functions remain poorly understood. As a result of this poor understanding, it is difficult to make mechanistically based recommendations for appropriate dietary intakes. It is equally difficult to develop methods that are capable of diagnosing functional impairments because of insufficiencies or excesses in particular fatty acids. Lipids are abundant building blocks of cellular membranes, supply components for lipid particle assembly and substrates for metabolic fuel, and provide a precursor pool for an astonishingly diverse range of signalling molecules. In each of these broad functions, the functional consequences of different structures of fatty acids are not fully understood. According to research on membrane functions through early evolution, docosahexaenoic acid provides two biophysical properties to membranes - accelerating the lateral motion of lipids and proteins within the plane of the membrane and simultaneously slowing the rate of diffusion/leakage of charged species across the plane of the membrane. The range of fatty acid structures used as substrates for assembly of either lipoproteins or milk fat globules is broad, yet the functional consequences of differences are not known. Different lipids signal into a remarkable range of biological processes. Saturated and monounsaturated fatty acids are becoming recognized as signal molecules in their own right. The complex composition of human milk lipids implies that diets with a diversity of fatty acids in complex lipid forms and structures is more beneficial than a narrow range of any particular group of fatty acids. PMID:21366863

  15. [Music therapy and "brain music": state of the art, problems and perspectives].

    PubMed

    Fedotchev, A I; Radchenko, G S

    2013-01-01

    Recent literature on the problem of interaction between music and the brain is reviewed and summarized. Mechanisms and effects of two most popular music therapy applications are picked out, including music listening and music making. Special attention is paid to relatively new line of investigations that is called "music of the brain" and deals with transformation of bioelectric processes of human organism into music. Unresolved questions of music therapy are identified and some promising lines of future investigations are delineated.

  16. Perspectives of pupils, parents, and teachers on mental health problems among Vietnamese secondary school pupils

    PubMed Central

    2013-01-01

    Background Secondary school can be a stressful period for adolescents, having to cope with many life changes. Very little research has been conducted on the mental health status of secondary school pupils in South East Asian countries, such as Vietnam. The study aimed to explore perceptions of mental health status, risk factors for mental health problems and strategies to improve mental health among Vietnamese secondary school students. Methods A qualitative design was used to address the main study question including: six in-depth interviews conducted with professionals (with two researchers, two psychiatrists, and two secondary school teachers) to learn about their experience of mental health problems among secondary school pupils; 13 focus group discussions (four with teachers, four with parents, and five with pupils); and 10 individual in-depth interviews with pupils who did not take part in the FGDs, to reflect on the collected data and to deepen the authors’ understanding. All interviews and FGDs were audio-taped, transcribed and analyzed for the identification of emerging issues using qualitative techniques of progressive coding, analytic memoing and ongoing comparison. Results Our study confirms the need to pay attention to mental health of pupils in Vietnam. Depression, anxiety, stress, suicidal thoughts and suicide attempts were seen as major problems by all stakeholders. Mental health problems were mainly associated with academic pressure, resulting from an overloaded curriculum and pressure from teachers and parents to succeed. The study found that pupils’ mental health demands interventions at many levels, including at the level of government (Ministry of Education and Training), schools, communities, families and pupils themselves. Conclusions Vietnamese secondary school pupils feel that their mental health status is poor, because of many risk factors in their learning and living environment. The need now is to investigate further to identify and

  17. [Music therapy and "brain music": state of the art, problems and perspectives].

    PubMed

    Fedotchev, A I; Radchenko, G S

    2013-01-01

    Recent literature on the problem of interaction between music and the brain is reviewed and summarized. Mechanisms and effects of two most popular music therapy applications are picked out, including music listening and music making. Special attention is paid to relatively new line of investigations that is called "music of the brain" and deals with transformation of bioelectric processes of human organism into music. Unresolved questions of music therapy are identified and some promising lines of future investigations are delineated. PMID:25438561

  18. [Music therapy and "brain music": state of the art, problems and perspectives].

    PubMed

    2013-01-01

    Recent literature on the problem of interaction between music and the brain is reviewed and summarized. Mechanisms and effects of two most popular music therapy applications are picked out, including music listening and music making. Special attention is paid to relatively new line of investigations that is called "music of the brain" and deals with transformation of bioelectric processes of human organism into music. Unresolved questions of music therapy are identified and some promising lines of future investigations are delineated. PMID:25508092

  19. A Conceptual Framework Mapping the Application of Information Search Strategies to Well and Ill-Structured Problem Solving

    ERIC Educational Resources Information Center

    Laxman, Kumar

    2010-01-01

    Problem-based learning (PBL) is an instructional approach that is organized around the investigation and resolution of problems. Problems are neither uniform nor similar. Jonassen (1997, 2000) in his design theory of problem solving has categorized problems into two broad types--well-structured and ill-structured. He has also described a host of…

  20. The Effect of Visual Representation Style in Problem-Solving: A Perspective from Cognitive Processes

    PubMed Central

    Nyamsuren, Enkhbold; Taatgen, Niels A.

    2013-01-01

    Using results from a controlled experiment and simulations based on cognitive models, we show that visual presentation style can have a significant impact on performance in a complex problem-solving task. We compared subject performances in two isomorphic, but visually different, tasks based on a card game of SET. Although subjects used the same strategy in both tasks, the difference in presentation style resulted in radically different reaction times and significant deviations in scanpath patterns in the two tasks. Results from our study indicate that low-level subconscious visual processes, such as differential acuity in peripheral vision and low-level iconic memory, can have indirect, but significant effects on decision making during a problem-solving task. We have developed two ACT-R models that employ the same basic strategy but deal with different presentations styles. Our ACT-R models confirm that changes in low-level visual processes triggered by changes in presentation style can propagate to higher-level cognitive processes. Such a domino effect can significantly affect reaction times and eye movements, without affecting the overall strategy of problem solving. PMID:24260415

  1. The Experimental Investigation of the Missing N*- and Δ-RESONANCES Problem:. Current Status and Perspectives

    NASA Astrophysics Data System (ADS)

    Sumachev, V. V.; Bekrenev, V. S.; Beloglazov, Yu. A.; Filimonov, E. A.; Kovalev, A. I.; Kozlenko, N. G.; Kruglov, S. P.; Kulbardis, A. A.; Lopatin, I. V.; Novinsky, D. V.; Shchedrov, V. A.; Trautman, V. Yu.; Alekseev, I. G.; Budkovsky, P. E.; Kanavets, V. P.; Koroleva, L. I.; Morozov, B. V.; Nesterov, V. M.; Ryltsov, V. V.; Sulimov, A. D.; Svirida, D. N.; Bazhanov, N. A.; Bunyatova, E. I.

    2007-11-01

    Numerous attempts to create a model that would exactly reproduce the N* - and Δ - resonances spectrum (that was presented in the Review of Particle Physics) failed. The existing models usually predicted considerably more resonances (twice or more in number) than were found in elastic πN - scattering. This problem is known as the problem of "missing" resonances. The recent partial wave analysis (PWA) SP06 that was made at George Washington University (2006) and included the modern experimental data revealed considerably fewer (approximately half) the N*- and Δ-resonances than those presented in the Review of Particle Physics (RPP) tables (2006). This disagreement invites further experimental investigation of the pion-nucleon interactions. Recent spin rotation parameter A and R measurements of the PNPI and PNPI-ITEP collaborations resolved a part of the twofold ambiguities of the PWA's. These results were used in the last PWA of the George Washington University (GWU) groups. The proposal for the additional measurements of the differential cross section and spin-rotation parameters R and A in the resonance region of the πN interactions is motivated. Such additional experiments are necessary to resolve the problem of the narrow (Γ < 30 MeV) baryon resonances existing and to complete monosemantic PWA of the πN elastic scattering.

  2. The effect of visual representation style in problem-solving: a perspective from cognitive processes.

    PubMed

    Nyamsuren, Enkhbold; Taatgen, Niels A

    2013-01-01

    Using results from a controlled experiment and simulations based on cognitive models, we show that visual presentation style can have a significant impact on performance in a complex problem-solving task. We compared subject performances in two isomorphic, but visually different, tasks based on a card game of SET. Although subjects used the same strategy in both tasks, the difference in presentation style resulted in radically different reaction times and significant deviations in scanpath patterns in the two tasks. Results from our study indicate that low-level subconscious visual processes, such as differential acuity in peripheral vision and low-level iconic memory, can have indirect, but significant effects on decision making during a problem-solving task. We have developed two ACT-R models that employ the same basic strategy but deal with different presentations styles. Our ACT-R models confirm that changes in low-level visual processes triggered by changes in presentation style can propagate to higher-level cognitive processes. Such a domino effect can significantly affect reaction times and eye movements, without affecting the overall strategy of problem solving. PMID:24260415

  3. Some New Problems on Shells and Thin Structures

    NASA Technical Reports Server (NTRS)

    Vlasov, V. S.

    1949-01-01

    Cylindrical shells of arbitrary section, reinforced by longitudinal and transverse members (stringers and ribs) are considered by us, for a sufficiently close spacing of the ribs, as in our previously published papers (references 1 end 2), as thin-walled orthotropic spatial systems at the cross-sections of which only axial (normal and shearing) forces can arise. The longitudinal bending and twisting moments, due to their weak effect on the stress state of the shell, are taken equal to zero. Along the longitudinal sections of the shell there may arise transverse forces in addition to the normal d shearing forces. Under the so-called static assumptions there is taken for the computation model of the shell a thin-walled spatial system consisting along its length (along a generator) of an infinite number of elementary strips capable of bending. Each of these strips is likened to a curved rod operating in each of its sections not only in tension (compression)but also in transverse bending and shear. The interaction between two adjoining transverse strips in the shell expresses itself in the transmission from one strip to the other of only the normal and shearing stresses. The static structure of the computation model here described is shown in figure 1, where the connections through which the normal and shearing stresses transmitted from one transverse strip to smother are indicated schematically by the rods located in the middle surface of the shell. In addition to the static hypothesis we introduce also geometric hypotheses. According to the latter the elongational deformations of the shell along lines parallel to the generator of its middle surface and the shear deformations in the middle surface, as ma+gitudes having . little effect on the state of the fundamental internal forces of the shell, are taken equal to zero. The deformations of the shell in our computational model are such that in the first place the lines of this surface perpendicular to the generator are

  4. Structure, function and evolution of the gas exchangers: comparative perspectives.

    PubMed

    Maina, J N

    2002-10-01

    Over the evolutionary continuum, animals have faced similar fundamental challenges of acquiring molecular oxygen for aerobic metabolism. Under limitations and constraints imposed by factors such as phylogeny, behaviour, body size and environment, they have responded differently in founding optimal respiratory structures. A quintessence of the aphorism that 'necessity is the mother of invention', gas exchangers have been inaugurated through stiff cost-benefit analyses that have evoked transaction of trade-offs and compromises. Cogent structural-functional correlations occur in constructions of gas exchangers: within and between taxa, morphological complexity and respiratory efficiency increase with metabolic capacities and oxygen needs. Highly active, small endotherms have relatively better-refined gas exchangers compared with large, inactive ectotherms. Respiratory structures have developed from the plain cell membrane of the primeval prokaryotic unicells to complex multifunctional ones of the modern Metazoa. Regarding the respiratory medium used to extract oxygen from, animal life has had only two choices--water or air--within the biological range of temperature and pressure the only naturally occurring respirable fluids. In rarer cases, certain animals have adapted to using both media. Gills (evaginated gas exchangers) are the primordial respiratory organs: they are the archetypal water breathing organs. Lungs (invaginated gas exchangers) are the model air breathing organs. Bimodal (transitional) breathers occupy the water-air interface. Presentation and exposure of external (water/air) and internal (haemolymph/blood) respiratory media, features determined by geometric arrangement of the conduits, are important features for gas exchange efficiency: counter-current, cross-current, uniform pool and infinite pool designs have variably developed. PMID:12430953

  5. Pilins in gram-positive bacteria: A structural perspective.

    PubMed

    Krishnan, Vengadesan

    2015-07-01

    Pilins or fimbrilins are a class of proteins found in bacterial surface pilus, a hair-like surface appendage. Both the Gram-negative and -positive bacteria produce pilins to assemble pili on their cell-surface for different purposes including adherence, twitching motility, conjugation, immunomodulation, biofilm formation, and electron transfer. Immunogenic properties of the pilins make them attractive vaccine candidates. The polymerized pilins play a key role in the initiation of host adhesion, which is a critical step for bacterial colonization and infection. Because of their key role in adhesion and exposure on the cell surface, targeting the pilins-mediated adhesion (anti-adhesion therapy) is also seen as a promising alternative approach for preventing and treating bacterial infections, one that may overcome their ever-increasing repertoires of resistance mechanisms. Individual pilins interact with each other non-covalently to assemble the pilus fiber with the help of associated proteins like chaperones and Usher in Gram-negative bacteria. In contrast, the pilins in Gram-positive bacteria often connect with each other covalently, with the help of sortases. Certain unique structural features present on the pilins distinguish them from one another across different bacterial strains, and these dictate their cellular targets and functions. While the structure of pilins has been extensively studied in Gram-negative pathogenic bacteria, the pilins in Gram-positive pathogenic bacteria have been in only during the last decade. Recently, the discovery of pilins in non-pathogenic bacteria, such as Lactobacillus rhamnosus GG, has received great attention, though traditionally the attention was on pathogenic bacteria. This review summarizes and discusses the current structural knowledge of pilins in Gram-positive bacteria with emphasis on those pilins which are sortase substrates.

  6. Evolutionary perspectives on protein structure, stability, and functionality

    NASA Astrophysics Data System (ADS)

    Goldstein, Richard A.

    Proteins are the result of a long process of evolution. It is due to this process that they have developed properties rather different from those of random strings of amino acids. If we wish to understand the properties of proteins, we need to understand the underlying process of Darwinian evolution, and how its stochastic nature interacts with the underlying fitness landscape. In this review, I describe some of the underlying theory of evolution. I then discuss how these theories can help us understand the structure, thermodynamics, and functioning of naturally-occurring proteins.

  7. Structure-property relationships of multiferroic materials: A nano perspective

    NASA Astrophysics Data System (ADS)

    Bai, Feiming

    The integration of sensors, actuators, and control systems is an ongoing process in a wide range of applications covering automotive, medical, military, and consumer electronic markets. Four major families of ceramic and metallic actuators are under development: piezoelectrics, electrostrictors, magnetostrictors, and shape-memory alloys. All of these materials undergo at least two phase transformations with coupled thermodynamic order parameters. These transformations lead to complex domain wall behaviors, which are driven by electric fields (ferroelectrics), magnetic fields (ferromagnetics), or mechanical stress (ferroelastics) as they transform from nonferroic to ferroic states, contributing to the sensing and actuating capabilities. This research focuses on two multiferroic crystals, Pb(Mg1/3Nb 2/3)O3-PbTiO3 and Fe-Ga, which are characterized by the co-existence and coupling of ferroelectric polarization and ferroelastic strain, or ferro-magnetization and ferroelastic strain. These materials break the conventional boundary between piezoelectric and electrostrictors, or magnetostrictors and shape-memory alloys. Upon applying field or in a poled condition, they yield not only a large strain but also a large strain over field ratio, which is desired and much benefits for advanced actuator and sensor applications. In this thesis, particular attention has been given to understand the structure-property relationships of these two types of materials from atomic to the nano/macro scale. X-ray and neutron diffraction were used to obtain the lattice structure and phase transformation characteristics. Piezoresponse and magnetic force microscopy were performed to establish the dependence of domain configurations on composition, thermal history and applied fields. It has been found that polar nano regions (PNRs) make significant contributions to the enhanced electromechanical properties of PMN-x%PT crystals via assisting intermediate phase transformation. With increasing PT

  8. Raman-based geobarometry of ultrahigh-pressure metamorphic rocks: applications, problems, and perspectives.

    PubMed

    Korsakov, Andrey V; Zhukov, Vladimir P; Vandenabeele, Peter

    2010-08-01

    Raman-based geobarometry has recently become increasingly popular because it is an elegant way to obtain information on peak metamorphic conditions or the entire pressure-temperature-time (P-T-t) path of metamorphic rocks, especially those formed under ultrahigh-pressure (UHP) conditions. However, several problems need to be solved to get reliable estimates of metamorphic conditions. In this paper we present some examples of difficulties which can arise during the Raman spectroscopy study of solid inclusions from ultrahigh-pressure metamorphic rocks.

  9. Research on alcohol problems from the perspective of changes--1940 to 1990.

    PubMed Central

    Straus, R

    1988-01-01

    The nature of alcohol problems, knowledge about alcohol use and abuse, and public perceptions and responses have all undergone substantial change during the past half-century. This paper traces some interrelationships between changes in alcohol-specific knowledge and behavior and other relevant social forces. The importance of change in the derivation, utilization, and interpretation of this knowledge is emphasized. Special emphasis is also placed on changes that make the integration of research between the biological and behavioral sciences desirable and necessary. PMID:3141968

  10. The Influence of Gender and Sexual Orientation on Alcohol Use and Alcohol-Related Problems: Toward a Global Perspective.

    PubMed

    Hughes, Tonda L; Wilsnack, Sharon C; Kantor, Lori Wolfgang

    2016-01-01

    Although there are wide differences in alcohol use patterns among countries, men are consistently more likely than women to be drinkers and to drink heavily. Studies of alcohol use among sexual minorities (SMs), however, reflect a more complex picture. Such research has found higher rates of alcohol use and alcohol-related problems among SM persons than among heterosexuals and greater differences between SM and heterosexual women than between SM and heterosexual men. A variety of factors may contribute to differences in alcohol use and alcohol-related problems between men and women and between SM and heterosexual people. An improved understanding of these factors is important to guide prevention and treatment efforts. Although there is a dearth of literature on use of alcohol by SMs in many parts of the world, especially lower- and middle-income countries, we attempt to review and integrate the sparse data that are available from these lower-resourced countries. The global perspective presented in this article is the first attempt to go beyond a general review of literature in the Western world to document the gender paradox in alcohol use among heterosexuals and SMs in diverse countries worldwide. PMID:27159819

  11. The Dreyfus model of clinical problem-solving skills acquisition: a critical perspective

    PubMed Central

    Peña, Adolfo

    2010-01-01

    Context The Dreyfus model describes how individuals progress through various levels in their acquisition of skills and subsumes ideas with regard to how individuals learn. Such a model is being accepted almost without debate from physicians to explain the ‘acquisition’ of clinical skills. Objectives This paper reviews such a model, discusses several controversial points, clarifies what kind of knowledge the model is about, and examines its coherence in terms of problem-solving skills. Dreyfus' main idea that intuition is a major aspect of expertise is also discussed in some detail. Relevant scientific evidence from cognitive science, psychology, and neuroscience is reviewed to accomplish these aims. Conclusions Although the Dreyfus model may partially explain the ‘acquisition’ of some skills, it is debatable if it can explain the acquisition of clinical skills. The complex nature of clinical problem-solving skills and the rich interplay between the implicit and explicit forms of knowledge must be taken into consideration when we want to explain ‘acquisition’ of clinical skills. The idea that experts work from intuition, not from reason, should be evaluated carefully. PMID:20563279

  12. Characterization of NEOs from the Policy Perspective: Implications from Problem and Solution Definitions

    NASA Astrophysics Data System (ADS)

    Lindquist, E.

    2015-12-01

    The characterization of near-Earth-objects (NEOs) in regard to physical attributes and potential risk and impact factors presents a complex and complicates scientific and engineering challenge. The societal and policy risks and impacts are no less complex, yet are rarely considered in the same context as material properties or related factors. The objective of this contribution is to position the characterization of NEOs within the public policy process domain as a means to reflect on the science-policy nexus in regard to risks associated with NEOs. This will be accomplished through, first, a brief overview of the science-policy nexus, followed by a discussion of several policy process frameworks, such as agenda setting and the multiple streams model, focusing events, and punctuated equilibrium, and their application and appropriateness to the problem of NEOs. How, too, for example, does NEO hazard and risk compare with other low probability, high risk, hazards in regard to public policy? Finally, we will reflect on the implications of alternative NEO "solutions" and the characterization of the NEO "problem," and the political and public acceptance of policy alternatives as a way to link NEO science and policy in the context of the overall NH004 panel.

  13. Near Earth Objects and Cascading Effects from the Policy Perspective: Implications from Problem and Solution Definition

    NASA Astrophysics Data System (ADS)

    Lindquist, Eric

    2016-04-01

    The characterization of near-Earth-objects (NEOs) in regard to physical attributes and potential risk and impact factors presents a complex and complicates scientific and engineering challenge. The societal and policy risks and impacts are no less complex, yet are rarely considered in the same context as material properties or related factors. Further, NEO impacts are typically considered as discrete events, not as initial events in a dynamic cascading system. The objective of this contribution is to position the characterization of NEOs within the public policy process domain as a means to reflect on the science-policy nexus in regard to risks and multi-hazard impacts associated with these hazards. This will be accomplished through, first, a brief overview of the science-policy nexus, followed by a discussion of policy process frameworks, such as agenda setting and the multiple streams model, focusing events, and punctuated equilibrium, and their application and appropriateness to the problem of NEOs. How, too, for example, does NEO hazard and risk compare with other low probability, high risk, hazards in regard to public policy? Finally, we will reflect on the implications of alternative NEO "solutions" and the characterization of the NEO "problem," and the political and public acceptance of policy alternatives as a way to link NEO science and policy in the context of the overall NH9.12 panel.

  14. Materials by Design—A Perspective From Atoms to Structures

    PubMed Central

    Buehler, Markus J.

    2013-01-01

    Biological materials are effectively synthesized, controlled, and used for a variety of purposes—in spite of limitations in energy, quality, and quantity of their building blocks. Whereas the chemical composition of materials in the living world plays a some role in achieving functional properties, the way components are connected at different length scales defines what material properties can be achieved, how they can be altered to meet functional requirements, and how they fail in disease states and other extreme conditions. Recent work has demonstrated this by using large-scale computer simulations to predict materials properties from fundamental molecular principles, combined with experimental work and new mathematical techniques to categorize complex structure-property relationships into a systematic framework. Enabled by such categorization, we discuss opportunities based on the exploitation of concepts from distinct hierarchical systems that share common principles in how function is created, linking music to materials science. PMID:24163499

  15. Materials by Design-A Perspective From Atoms to Structures.

    PubMed

    Buehler, Markus J

    2013-02-01

    Biological materials are effectively synthesized, controlled, and used for a variety of purposes-in spite of limitations in energy, quality, and quantity of their building blocks. Whereas the chemical composition of materials in the living world plays a some role in achieving functional properties, the way components are connected at different length scales defines what material properties can be achieved, how they can be altered to meet functional requirements, and how they fail in disease states and other extreme conditions. Recent work has demonstrated this by using large-scale computer simulations to predict materials properties from fundamental molecular principles, combined with experimental work and new mathematical techniques to categorize complex structure-property relationships into a systematic framework. Enabled by such categorization, we discuss opportunities based on the exploitation of concepts from distinct hierarchical systems that share common principles in how function is created, linking music to materials science. PMID:24163499

  16. Twin Masks of Spiral Structure? A Local Perspective

    NASA Astrophysics Data System (ADS)

    Steiman-Cameron, Thomas Y.

    We examine models for the spiral structure of the Milky Way proposed over the past half century. Many approaches have been pursued to decipher the geometry of the Galaxy's spiral arms, often with conflicting results. While a general consensus exists that a global pattern exists, considerable disagreement remains in the details. Arm geometries, orientations, and even the number of arms are still debated. Close examination of the literature reveals a clear division between four- and two-arm spiral arms. Four-arm models follow naturally from observations of classical tracers of spiral arms - enhanced gas densities and associated star formation - while two-arm models primarily flow from observations linked to the distribution of cool evolved stars. We examine the dichotomy between two-arm and four-arm models and discuss its implications.

  17. Assessing psychopathology from a structural perspective: A psychodynamic model.

    PubMed

    Trimboli, Frank; Marshall, Rycke L; Keenan, Charles W

    2013-01-01

    This article presents a guide for conceptualizing psychological difficulties across the broad spectrum of personality and symptom disorders. A psychodynamic model is used to organize these disorders along a structural continuum of severity. The authors propose that seven key indices of personality functioning be evaluated: cognition, affect, self-object relations, interpersonal relations, defenses, superego functioning, and primary dynamics. The results are then employed to determine where the patient should be placed along a continuum of nine diagnostic categories of ego development and their associated disorders. These include "normal," neurotic trait, and neurotic symptom organization; high-, mid-, and low-level borderline organization; and affective, cognitive-affective, and cognitive psychotic organization. An accurate evaluation of the seven variables will permit a more precise formulation of the nature and severity of the patient's difficulties, which will hopefully result in more accurate and appropriate treatment planning. Examples of the application of this model to a common symptom complaint are provided. PMID:23697819

  18. Materials by Design-A Perspective From Atoms to Structures.

    PubMed

    Buehler, Markus J

    2013-02-01

    Biological materials are effectively synthesized, controlled, and used for a variety of purposes-in spite of limitations in energy, quality, and quantity of their building blocks. Whereas the chemical composition of materials in the living world plays a some role in achieving functional properties, the way components are connected at different length scales defines what material properties can be achieved, how they can be altered to meet functional requirements, and how they fail in disease states and other extreme conditions. Recent work has demonstrated this by using large-scale computer simulations to predict materials properties from fundamental molecular principles, combined with experimental work and new mathematical techniques to categorize complex structure-property relationships into a systematic framework. Enabled by such categorization, we discuss opportunities based on the exploitation of concepts from distinct hierarchical systems that share common principles in how function is created, linking music to materials science.

  19. Structure, function and evolution of the gas exchangers: comparative perspectives

    PubMed Central

    Maina, JN

    2002-01-01

    Over the evolutionary continuum, animals have faced similar fundamental challenges of acquiring molecular oxygen for aerobic metabolism. Under limitations and constraints imposed by factors such as phylogeny, behaviour, body size and environment, they have responded differently in founding optimal respiratory structures. A quintessence of the aphorism that ‘necessity is the mother of invention’, gas exchangers have been inaugurated through stiff cost–benefit analyses that have evoked transaction of trade-offs and compromises. Cogent structural–functional correlations occur in constructions of gas exchangers: within and between taxa, morphological complexity and respiratory efficiency increase with metabolic capacities and oxygen needs. Highly active, small endotherms have relatively better-refined gas exchangers compared with large, inactive ectotherms. Respiratory structures have developed from the plain cell membrane of the primeval prokaryotic unicells to complex multifunctional ones ofthe modern Metazoa. Regarding the respiratory medium used to extract oxygen from, animal life has had only two choices – water or air – within the biological range of temperature and pressure the only naturally occurring respirable fluids. In rarer cases, certain animalshave adapted to using both media. Gills (evaginated gas exchangers) are the primordial respiratory organs: they are the archetypal water breathing organs. Lungs (invaginated gas exchangers) are the model air breathing organs. Bimodal (transitional) breathers occupy the water–air interface. Presentation and exposure of external (water/air) and internal (haemolymph/blood) respiratory media, features determined by geometric arrangement of the conduits, are important features for gas exchange efficiency: counter-current, cross-current, uniform pool and infinite pool designs have variably developed. PMID:12430953

  20. Self-structuring properties of dominance hierarchies a new perspective.

    PubMed

    Chase, Ivan D; Seitz, Kristine

    2011-01-01

    Using aggressive behavior, animals of many species establish dominance hierarchies in both nature and the laboratory. Rank in these hierarchies influences many aspects of animals' lives including their health, physiology, weight gain, genetic expression, and ability to reproduce and raise viable offspring. In this chapter, we define dominance relationships and dominance hierarchies, discuss several model species used in dominance studies, and consider factors that predict the outcomes of dominance encounters in dyads and small groups of animals. Researchers have shown that individual differences in attributes, as well as in states (recent behavioral experiences), influence the outcomes of dominance encounters in dyads. Attributes include physical, physiological, and genetic characteristics while states include recent experiences such as winning or losing earlier contests. However, surprisingly, we marshal experimental and theoretical evidence to demonstrate that these differences have significantly less or no ability to predict the outcomes of dominance encounters for animals in groups as small as three or four individuals. Given these results, we pose an alternative research question: How do animals of so many species form hierarchies with characteristic linear structures despite the relatively low predictability based upon individual differences? In answer to this question, we review the evidence for an alternative approach suggesting that dominance hierarchies are self-structuring. That is, we suggest that linear forms of organization in hierarchies emerge from several kinds of behavioral processes, or sequences of interaction, that are common across many different species of animals from ants to chickens and fish and even some primates. This new approach inspires a variety of further questions for research.

  1. Evidence of Second-Order Factor Structure in a Diagnostic Problem Space: Implications for Medical Education.

    ERIC Educational Resources Information Center

    Papa, Frank J.; And Others

    1997-01-01

    Chest pain was identified as a specific medical problem space, and disease classes were modeled to define it. Results from a test taken by 628 medical residents indicate a second-order factor structure that suggests that chest pain is a multidimensional problem space. Implications for medical education are discussed. (SLD)

  2. Percentages: The Effect of Problem Structure, Number Complexity and Calculation Format

    ERIC Educational Resources Information Center

    Baratta, Wendy; Price, Beth; Stacey, Kaye; Steinle, Vicki; Gvozdenko, Eugene

    2010-01-01

    This study reports how the difficulty of simple worded percentage problems is affected by the problem structure and the complexity of the numbers involved. We also investigate which methods students know. Results from 677 Year 8 and 9 students are reported. Overall the results indicate that more attention needs to be given to this important topic.…

  3. Structured Parenting of Toddlers at High versus Low Genetic Risk: Two Pathways to Child Problems

    ERIC Educational Resources Information Center

    Leve, Leslie D.; Harold, Gordon T.; Ge, Xiaojia; Neiderhiser, Jenae M.; Shaw, Daniel; Scaramella, Laura V.; Reiss, David

    2009-01-01

    Objective: Little is known about how parenting might offset genetic risk to prevent the onset of child problems during toddlerhood. We used a prospective adoption design to separate genetic and environmental influences and test whether associations between structured parenting and toddler behavior problems were conditioned by genetic risk for…

  4. Structural Variables That Determine Problem-Solving Difficulty in Computer Assisted Instruction

    ERIC Educational Resources Information Center

    Loftus, Elizabeth F.; Suppes, Patrick

    1972-01-01

    Analysis showed that a word problem is difficult to solve if: it is of a different type from the problem that preceded it; its solution requires a large number of different operations; its surface structure is complex; it has a large number of words; or it requires a conversion of units. (Authors)

  5. How Instructional Design Experts Use Knowledge and Experience to Solve Ill-Structured Problems

    ERIC Educational Resources Information Center

    Ertmer, Peggy A.; Stepich, Donald A.; York, Cindy S.; Stickman, Ann; Wu, Xuemei (Lily); Zurek, Stacey; Goktas, Yuksel

    2008-01-01

    This study examined how instructional design (ID) experts used their prior knowledge and previous experiences to solve an ill-structured instructional design problem. Seven experienced designers used a think-aloud procedure to articulate their problem-solving processes while reading a case narrative. Results, presented in the form of four…

  6. Perceptual Learning in Early Mathematics: Interacting with Problem Structure Improves Mapping, Solving and Fluency

    ERIC Educational Resources Information Center

    Thai, Khanh-Phuong; Son, Ji Y.; Hoffman, Jessica; Devers, Christopher; Kellman, Philip J.

    2014-01-01

    Mathematics is the study of structure but students think of math as solving problems according to rules. Students can learn procedures, but they often have trouble knowing when to apply learned procedures, especially to problems unlike those they trained with. In this study, the authors rely on the psychological mechanism of perceptual learning…

  7. Clinician and Parent Perspectives on Parent and Family Contextual Factors that Impact Community Mental Health Services for Children with Behavior Problems

    ERIC Educational Resources Information Center

    Baker-Ericzen, Mary J.; Jenkins, Melissa M.; Brookman-Frazee, Lauren

    2010-01-01

    The present study employed qualitative methods to examine multiple stakeholder perspectives regarding the role of parent and family contextual factors on community child mental health treatment for children with behavior problems. Findings suggest agreement between clinicians and parents on the number, types and importance of parent and family…

  8. The adaptability rating for military aeronautics: an historical perspective of a continuing problem.

    PubMed

    Mills, J G; Jones, D R

    1984-06-01

    Healthy candidates for military flying training may vary considerably in their ability and in their motivation to fly. A variety of tests are used to predict flying ability, but motivation may be assessed only through such subjective measures as a semi-structured interview. This paper reviews the historical background of such interviews in the U.S. Army and the U.S. Air Force, and suggests some possible improvements.

  9. Metals for Cryotank Structures. Present and Future: MSFC Perspective

    NASA Technical Reports Server (NTRS)

    Vaughn, Timothy P.

    1999-01-01

    The Cryogenic Tank Technology Program (CTTP) program has been a cooperative effort between NASA LARC, NASA MSFC, NASA Headquarters, and industry (Lockheed Martin Aeronautics, Lockheed Martin Manned Space Systems, Wyman Gordon, and Ladish). The scope of the CTTP is to develop state-of-the-art, flight-size, flight-quality, low cost hardware, and use this hardware to design, fabricate and test an all aluminum-lithium, all near net shape-component 14' diameter cryogenic tank with a unique low profile bulkhead design. The logical conclusion to the CTTP is to validate these various technologies to a Technology Readiness Level (TRL) of 6 through the proposed structural test program. The CTTP supports the advancement of key enabling technologies required for aluminum lithium cryogenic tanks. The technologies are focused towards innovative and low cost manufacturing processes such as near net shape technologies: one piece spun formed domes, extruded barrel panels, and one piece roll forged ring frames. Other innovative technologies include the friction stir weld process and weight-efficient low profile bulkhead designs. All of these technologies are of primary importance for NASA's mission plan for reusable and expendable launch vehicles. This program fills the niche for an all 2195 aluminum lithium alloy cryogenic tank which is not being covered by existing NASA technology work.

  10. Composites for Cryotank Structures. Present and Future: MSFC Perspective

    NASA Technical Reports Server (NTRS)

    Vaughn, Timothy P.

    1999-01-01

    The development of reusable launch vehicle systems for a single stage to orbit vehicle requires vehicles at liftoff with 85% to 94% of its mass consisting exclusively of propellants. These dry mass requirements drive designs to utilize stronger, lighter weight materials for structures. This technology development focus has allowed the introduction of composite materials in lieu of conventional metallic materials due to their higher specific strengths. Composite materials were successfully used for the liquid hydrogen tanks for the DC-XA, and a multi-lobed liquid hydrogen tank will be employed for the X-33. Another potential non-traditional application for composite materials is for liquid oxygen tanks, which is still being investigated. Traditionally, organic materials have been avoided wherever possible, due the potential fire hazard and the fact that composites fail conventional oxygen compatibility requirements. However, the potential weight savings warrant the investigation of the use of polymeric composite materials in oxygen environments. Since composites fail the conventional, time-proven test methods because they are considered flammable by test, we have embarked on an innovative approach to oxygen compatibility testing and evaluation focused on the use environments and attempts to eliminate or "design away" all potential ignition sources. Oxygen compatibility is defined as the ability of a material to coexist with oxygen and potential ignition sources with an acceptable, manageable degree of risk.

  11. Richat Structure, Mauritania, Perspective View, Landsat Image over SRTM Elevation

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This prominent circular feature, known as the Richat Structure, in the Sahara desert of Mauritania is often noted by astronauts because it forms a conspicuous 50-kilometer-wide (30-mile-wide) bull's-eye on the otherwise rather featureless expanse of the desert. Initially mistaken for a possible impact crater, it is now known to be an eroded circular anticline (structural dome) of layered sedimentary rocks.

    Extensive sand dunes occur in this region and the interaction of bedrock topography, wind, and moving sand is evident in this scene. Note especially how the dune field ends abruptly short of the cliffs at the far right as wind from the northeast (lower right) apparently funnels around the cliff point, sweeping clean areas near the base of the cliff. Note also the small isolated peak within the dune field. That peak captures some sand on its windward side, but mostly deflects the wind and sand around its sides, creating a sand-barren streak that continues far downwind.

    This view was generated from a Landsat satellite image draped over an elevation model produced by the Shuttle Radar Topography Mission (SRTM). The view uses a 6-times vertical exaggeration to greatly enhance topographic expression. For vertical scale, note that the height of the mesa ridge in the back center of the view is about 285 meters (about 935 feet) tall. Colors of the scene were enhanced by use of a combination of visible and infrared bands, which helps to differentiate bedrock (browns), sand (yellow, some white), minor vegetation in drainage channels (green), and salty sediments (bluish whites). Some shading of the elevation model was included to further highlight the topographic features.

    Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR

  12. The mediating role of perceived peer support in the relation between quality of attachment and internalizing problems in adolescence: a longitudinal perspective.

    PubMed

    Pace, Ugo; Zappulla, Carla; Di Maggio, Rosanna

    2016-10-01

    The study was aimed to verify, from a longitudinal perspective, whether perceived peer support would mediate the relationship between attachment and internalizing problems. Longitudinal participants included 482 adolescents (245 boys) aged 14-15 years in Wave 1 and 17-18 years in Wave 2. Participants in Wave 1 completed the Relationship Questionnaire, and those in Wave 2 completed the Social Support Questionnaire and the Youth Self-Report. Results showed that secure attachment positively predicted high levels of perceived peer support and negatively predicted internalizing problems, whereas fearful and preoccupied attachment negatively predicted perceived peer support and positively predicted internalizing problems. The mediation models showed that perceived peer support partially mediated the relationship between secure attachment and internalizing problems as well as between preoccupied attachment and internalizing problems and between fearful attachment and internalizing problems. Our results confirm the role of subjective perception of peer support in contributing to the prediction of internalizing problems beyond attachment styles.

  13. The cosmological {sup 7}Li problem from a nuclear physics perspective

    SciTech Connect

    Broggini, C.; Canton, L.; Fiorentini, G.; Villante, F.L. E-mail: luciano.canton@pd.infn.it E-mail: francesco.villante@lngs.infn.it

    2012-06-01

    The primordial abundance of {sup 7}Li as predicted by Big Bang Nucleosynthesis (BBN) is more than a factor 2 larger than what has been observed in metal-poor halo stars. Herein, we analyze the possibility that this discrepancy originates from incorrect assumptions about the nuclear reaction cross sections relevant for BBN. To do this, we introduce an efficient method to calculate the changes in the {sup 7}Li abundance produced by arbitrary (temperature dependent) modifications of the nuclear reaction rates. Then, considering that {sup 7}Li is mainly produced from {sup 7}Be via the electron capture process {sup 7}Be+e{sup −} → {sup 7}Li+ν{sub e}, we assess the impact of the various channels of {sup 7}Be destruction. Differently from previous analysis, we consider the role of unknown resonances by using a complete formalism which takes into account the effect of Coulomb and centrifugal barrier penetration and that does not rely on the use of the narrow-resonance approximation. As a result of this, the possibility of a nuclear physics solution to the {sup 7}Li problem is significantly suppressed. Given the present experimental and theoretical constraints, it is unlikely that the {sup 7}Be+n destruction rate is underestimated by the 2.5 factor required to solve the problem. We exclude, moreover, that resonant destruction in the channels {sup 7}Be+t and {sup 7}Be+{sup 3}He can explain the {sup 7}Li puzzle. New unknown resonances in {sup 7}Be+d and {sup 7}Be+α could potentially produce significant effects. Recent experimental results have ruled out such a possibility for {sup 7}Be+d. On the other hand, for the {sup 7}Be+α channel very favorable conditions are required. The possible existence of a partially suitable resonant level in {sup 11}C is studied in the framework of a coupled-channel model and the possibility of a direct measurement is considered.

  14. Studies on clonogenic hemopoietic cells of vertebrate in space: problems and perspectives

    NASA Astrophysics Data System (ADS)

    Domaratskaya, E. I.; Michurina, T. V.; Bueverova, E. I.; Bragina, E. V.; Nikonova, T. A.; Starostin, V. I.; Khrushchov, N. G.

    Hemopoietic tissues were studied in vertebrates launched aboard the Soviet (Russian) biosatellites ("Cosmos-1129, 1514, 1667, 1887 and 2044"; "Bion-10 and 11") between 1980 and 1996. In the bone marrow of rats exposed to spaceflight conditions, a statistically significant decrease in cell number was revealed in the progenitor cell compartment accounting for the compensatory response of granulocyte—macrophage (CFU-gm) and erythrocyte lineages (BFU-e and CFU-e) and in the compartment of multipotent hemopoietic stem cells (CFU-s), which is responsible for the permanent renewal of hemopoietic tissue. The number of stromal fibroblastic progenitors (CFC-f) in the bone marrow of these rats was also reduced. Apparently, changes in the hemopoietic stroma damage the hemopoietic microenvironment and, hence, may be responsible for changes observed in the hemopoietic tissue proper. Attempts were made to develop methods for analyzing morphologically indiscernible clonogenic hemopoietic cells of newts, and studies on the effects of spaceflight factors on these cells were performed. The results showed that the numbers of clonogenic cells in newts of the flight group newts were significantly lower than in control newts. The data obtained are used as the basis for formulating the problems to be studied, drawing up a program for further research on the effects of spaceflight factors on stem and other clonogenic hemopoietic cells, and developing new experimental models for analyzing stem cells, the state of the hemopoietic stroma, etc.

  15. Hyperthermia in the treatment of cancer. Perspectives on its promise and its problems.

    PubMed

    Stewart, J R; Gibbs, F A

    1984-12-01

    The potential for the use of hyperthermia in the treatment of cancer is based on a strong and compelling biologic rationale. In the laboratory it has been shown in quantitative assays both in vitro and in vivo that (1) hyperthermia is cytotoxic to tumor cells as a function of time at temperatures above 42 degrees C; (2) cytotoxicity is relatively high for radioresistant S-phase cells and for cells that are nutritionally deprived and acidotic, conditions one might expect in regions of tumors containing large numbers of radioresistant hypoxic cells; and (3) heat is a radiosensitizer and a chemosensitizer. Clinical study is hampered by less than optimal physical heating methods and the need for invasive thermometry. Ultrasonic and electromagnetic approaches each have limitations and advantages. In spite of technical limitations, efficacy has been shown for superficial tumor sites treated by local hyperthermia and Phase I studies are underway investigating the more complicated problem of deep regional hyperthermia. Although whole body hyperthermia has the attractive capability of treating metastatic as well as more localized cancer, it is toxic therapy and its role in treatment remains undefined. Research advances in equipment design and treatment optimization are needed; however, there are studies underway utilizing existing methods and rationale which should further clarify the potential clinical usefulness of regional hyperthermia in combined modality approaches to cancer therapy.

  16. Debates—Perspectives on socio-hydrology: Modeling flood risk as a public policy problem

    NASA Astrophysics Data System (ADS)

    Gober, Patricia; Wheater, Howard S.

    2015-06-01

    Socio-hydrology views human activities as endogenous to water system dynamics; it is the interaction between human and biophysical processes that threatens the viability of current water systems through positive feedbacks and unintended consequences. Di Baldassarre et al. implement socio-hydrology as a flood risk problem using the concept of social memory as a vehicle to link human perceptions to flood damage. Their mathematical model has heuristic value in comparing potential flood damages in green versus technological societies. It can also support communities in exploring the potential consequences of policy decisions and evaluating critical policy tradeoffs, for example, between flood protection and economic development. The concept of social memory does not, however, adequately capture the social processes whereby public perceptions are translated into policy action, including the pivotal role played by the media in intensifying or attenuating perceived flood risk, the success of policy entrepreneurs in keeping flood hazard on the public agenda during short windows of opportunity for policy action, and different societal approaches to managing flood risk that derive from cultural values and economic interests. We endorse the value of seeking to capture these dynamics in a simplified conceptual framework, but favor a broader conceptualization of socio-hydrology that includes a knowledge exchange component, including the way modeling insights and scientific results are communicated to floodplain managers. The social processes used to disseminate the products of socio-hydrological research are as important as the research results themselves in determining whether modeling is used for real-world decision making.

  17. [The transcultural perspective in health promotion, not just a problem of language. Transculturation and health promotion].

    PubMed

    Angelino, E

    2007-01-01

    Health behaviours, physician-patient communication and health outcomes are all influenced by the individual's perception of illness, which in turn is significantly influenced by one's cultural background. The nature of communication between people from different cultural groups is a complex phenomenon: communication even in a shared language can be hindered by the ambiguity of words that carry multiple meanings. Creating an environment of cultural awareness and sensitivity which respects the different values and beliefs of individuals is a first step in resolving this problem. Health education programs must take into account the subjective experience of illness, and on this basis promote collaboration with the patient, so improving not only the clinical outcome but also the patient's perceived satisfaction. Despite the current, general trend to promote the need for training of health professionals to give sensitive, empathetic patient care that guarantees full respect for the individual's autonomy, there are few empirical data available on the link between specific cultural skills and improved health care.

  18. An integer programming approach to the phase problem for centrosymmetric structures.

    PubMed

    Vaia, Anastasia; Sahinidis, Nikolaos V

    2003-09-01

    The problem addressed in this paper is the determination of three-dimensional structures of centrosymmetric crystals from X-ray diffraction measurements. The 'minimal principle' that a certain quantity is minimized only by the crystal structure is employed to solve the phase problem. The mathematical formulation of the minimal principle is a nonconvex nonlinear optimization problem. To date, local optimization techniques and advanced computer architectures have been used to solve this problem, which may have a very large number of local optima. In this paper, the minimal principle model is reformulated for the case of centrosymmetric structures into an integer programming problem in terms of the missing phases. This formulation is solvable by well established combinatorial optimization techniques that are guaranteed to provide the global optimum in a finite number of steps without explicit enumeration of all possible combinations of phases. Computational experience with the proposed method on a number of structures of moderate complexity is provided and demonstrates that the approach yields a fast and reliable method that resolves the crystallographic phase problem for the case of centrosymmetric structures. PMID:12944609

  19. Opportunity Structure for Gambling and Problem Gambling among Employees in the Transport Industry

    ERIC Educational Resources Information Center

    Revheim, Tevje; Buvik, Kristin

    2009-01-01

    Working conditions for employees in the transport sector might present an opportunity structure for gambling by providing access to gambling during the workday. This study investigates connections between opportunity structure, gambling during the workday, and gambling problems among employees in the transport sector. Data has been collected from…

  20. Analysis, preliminary design and simulation systems for control-structure interaction problems

    NASA Technical Reports Server (NTRS)

    Park, K. C.; Alvin, Kenneth F.

    1991-01-01

    Software aspects of control-structure interaction (CSI) analysis are discussed. The following subject areas are covered: (1) implementation of a partitioned algorithm for simulation of large CSI problems; (2) second-order discrete Kalman filtering equations for CSI simulations; and (3) parallel computations and control of adaptive structures.

  1. The Influence of Science Knowledge Structures on Children's Success in Solving Academic Problems.

    ERIC Educational Resources Information Center

    Champagne, Audrey B.; And Others

    Presented is a study of eighth-grade students' academic problem-solving ability based on their knowledge structures, or their information stored in semantic or long-term memory. The authors describe a technique that they developed to probe knowledge structures with an extension of the card-sort method. The method, known as the Concept Structure…

  2. Basic problems of digital simulation of solid rocket motor (SRM) structural reliability

    NASA Astrophysics Data System (ADS)

    Tan, Sanwu; Wang, Binxun

    1993-08-01

    Discussed are several basic problems in the digital simulation of SRM structural reliability, such as verification testing for critical components. Simulations of fiber-reinforced composite cases and SRM solid grains are presented to illustrate the general program of digital simulation for SRM structural reliability.

  3. Structural limitations for optimizing garnet-type solid electrolytes: a perspective.

    PubMed

    Zeier, Wolfgang G

    2014-11-21

    Lithium ion batteries exhibit the highest energy densities of all battery types and are therefore an important technology for energy storage in every day life. Today's commercially available batteries employ organic polymer lithium conducting electrolytes, leading to multiple challenges and safety issues such as poor chemical stability, leakage and flammability. The next generation lithium ion batteries, namely all solid-state batteries, can overcome these limitations through employing a ceramic Li(+) conducting electrolyte. In the past decade, there has been a major focus on the structural and ionic transport properties of lithium-conducting garnets, and the extensive research efforts have led to a thorough understanding of the structure-property relationships in this class of materials. However, further improvement seems difficult due to structural limitations. The purpose of this Perspective article is to provide a brief structural overview of Li conducting garnets and the structural influence on the optimization of Li-ionic conductivities. PMID:25277079

  4. Preparation of biosilica structures from frustules of diatoms and their applications: current state and perspectives.

    PubMed

    Wang, Yu; Cai, Jun; Jiang, Yonggang; Jiang, Xinggang; Zhang, Deyuan

    2013-01-01

    Frustules, the silica shells of diatoms, have unique porous architectures with good mechanical strength. In recent years, biologists have learned more about the mechanism of biosilica shells formation; meanwhile, physicists have revealed their optical and microfluidic properties, and chemists have identified ways to modify them into various materials while maintaining their hierarchical structures. These efforts have provided more opportunities to use biosilica structures in microsystems and other commercial products. This review focuses on the preparation of biosilica structures and their applications, especially in the development of microdevices. We discuss existing methods of extracting biosilica from diatomite and diatoms, introduce methods of separating biosilica structures by shape and sizes, and summarize recent studies on diatom-based devices used for biosensing, drug delivery, and energy applications. In addition, we introduce some new findings on diatoms, such as the elastic deformable characteristics of biosilica structures, and offer perspectives on planting diatom biosilica in microsystems.

  5. Structural limitations for optimizing garnet-type solid electrolytes: a perspective.

    PubMed

    Zeier, Wolfgang G

    2014-11-21

    Lithium ion batteries exhibit the highest energy densities of all battery types and are therefore an important technology for energy storage in every day life. Today's commercially available batteries employ organic polymer lithium conducting electrolytes, leading to multiple challenges and safety issues such as poor chemical stability, leakage and flammability. The next generation lithium ion batteries, namely all solid-state batteries, can overcome these limitations through employing a ceramic Li(+) conducting electrolyte. In the past decade, there has been a major focus on the structural and ionic transport properties of lithium-conducting garnets, and the extensive research efforts have led to a thorough understanding of the structure-property relationships in this class of materials. However, further improvement seems difficult due to structural limitations. The purpose of this Perspective article is to provide a brief structural overview of Li conducting garnets and the structural influence on the optimization of Li-ionic conductivities.

  6. Exact solution to the problem of N bodies forming a multi-layer rotating structure.

    PubMed

    Smulsky, Joseph J

    2015-01-01

    Exact solutions to the problem of the Newtonian gravitational interaction of N material points moving around N 2 concentric circular orbits are considered. Each circular orbit contains N 3 axisymmetrically located bodies having identical masses. The structure as a whole rotates around its symmetry axis. Such structures are identical to the homographic-dynamics configurations, or planar central configurations, known from literature. Conceptually, those structures can be considered as structures formed by mutually embedded polygons with point bodies placed at polygon vortices. For structures involving less than 20 bodies, solutions were obtained using Hamiltonian-mechanics methods. In the study, the forces acting on each body in the rotating structure from the side of all other bodies were found. The differential motion equations of the bodies were reduced to a system of linear algebraic equations for the body masses. Solutions in various forms were obtained. For specifying the initial parameters and for calculating all other characteristics of the structures, a computer program RtCrcSt2.for has been developed. Structures comprising up to one million bodies have been calculated. Graphical images of obtained structures are presented, and their properties are described. Stability problems for examined structures are considered, and possible application of obtained results to celestial- and space-mechanics problems is discussed. PMID:26203407

  7. Exact solution to the problem of N bodies forming a multi-layer rotating structure.

    PubMed

    Smulsky, Joseph J

    2015-01-01

    Exact solutions to the problem of the Newtonian gravitational interaction of N material points moving around N 2 concentric circular orbits are considered. Each circular orbit contains N 3 axisymmetrically located bodies having identical masses. The structure as a whole rotates around its symmetry axis. Such structures are identical to the homographic-dynamics configurations, or planar central configurations, known from literature. Conceptually, those structures can be considered as structures formed by mutually embedded polygons with point bodies placed at polygon vortices. For structures involving less than 20 bodies, solutions were obtained using Hamiltonian-mechanics methods. In the study, the forces acting on each body in the rotating structure from the side of all other bodies were found. The differential motion equations of the bodies were reduced to a system of linear algebraic equations for the body masses. Solutions in various forms were obtained. For specifying the initial parameters and for calculating all other characteristics of the structures, a computer program RtCrcSt2.for has been developed. Structures comprising up to one million bodies have been calculated. Graphical images of obtained structures are presented, and their properties are described. Stability problems for examined structures are considered, and possible application of obtained results to celestial- and space-mechanics problems is discussed.

  8. Finite element analysis of structural engineering problems using a viscoplastic model incorporating two back stresses

    NASA Technical Reports Server (NTRS)

    Arya, Vinod K.; Halford, Gary R.

    1993-01-01

    The feasibility of a viscoplastic model incorporating two back stresses and a drag strength is investigated for performing nonlinear finite element analyses of structural engineering problems. To demonstrate suitability for nonlinear structural analyses, the model is implemented into a finite element program and analyses for several uniaxial and multiaxial problems are performed. Good agreement is shown between the results obtained using the finite element implementation and those obtained experimentally. The advantages of using advanced viscoplastic models for performing nonlinear finite element analyses of structural components are indicated.

  9. Family Structure and Adolescent Alcohol Use Problems: Extending Popular Explanations to American Indiansc

    PubMed Central

    Eitle, Tamela McNulty; Johnson-Jennings, Michelle; Eitle, David J.

    2013-01-01

    Competing explanations of the relationship between family structure and alcohol use problems are examined using a sample of American Indian adolescents from the National Longitudinal Study of Adolescent Health. Living in a single-parent family is found to be a marker for the unequal distribution of stress exposure and parental alcohol use, but the effects of other family structures like non-parent families and the presence of under 21-year-old extended family or non-family members emerge or remain as risk or protective factors for alcohol use problems after a consideration of SES, family processes, peer socialization, and social stress. In particular, a non-parent family structure that has not been considered in prior research emerged as a protective family structure for American Indian adolescent alcohol use problems. PMID:24014896

  10. Geographic variation in plant community structure of salt marshes: species, functional and phylogenetic perspectives.

    PubMed

    Guo, Hongyu; Chamberlain, Scott A; Elhaik, Eran; Jalli, Inder; Lynes, Alana-Rose; Marczak, Laurie; Sabath, Niv; Vargas, Amy; Więski, Kazimierz; Zelig, Emily M; Pennings, Steven C

    2015-01-01

    In general, community similarity is thought to decay with distance; however, this view may be complicated by the relative roles of different ecological processes at different geographical scales, and by the compositional perspective (e.g. species, functional group and phylogenetic lineage) used. Coastal salt marshes are widely distributed worldwide, but no studies have explicitly examined variation in salt marsh plant community composition across geographical scales, and from species, functional and phylogenetic perspectives. Based on studies in other ecosystems, we hypothesized that, in coastal salt marshes, community turnover would be more rapid at local versus larger geographical scales; and that community turnover patterns would diverge among compositional perspectives, with a greater distance decay at the species level than at the functional or phylogenetic levels. We tested these hypotheses in salt marshes of two regions: The southern Atlantic and Gulf Coasts of the United States. We examined the characteristics of plant community composition at each salt marsh site, how community similarity decayed with distance within individual salt marshes versus among sites in each region, and how community similarity differed among regions, using species, functional and phylogenetic perspectives. We found that results from the three compositional perspectives generally showed similar patterns: there was strong variation in community composition within individual salt marsh sites across elevation; in contrast, community similarity decayed with distance four to five orders of magnitude more slowly across sites within each region. Overall, community dissimilarity of salt marshes was lowest on the southern Atlantic Coast, intermediate on the Gulf Coast, and highest between the two regions. Our results indicated that local gradients are relatively more important than regional processes in structuring coastal salt marsh communities. Our results also suggested that in

  11. Geographic Variation in Plant Community Structure of Salt Marshes: Species, Functional and Phylogenetic Perspectives

    PubMed Central

    Guo, Hongyu; Chamberlain, Scott A.; Elhaik, Eran; Jalli, Inder; Lynes, Alana-Rose; Marczak, Laurie; Sabath, Niv; Vargas, Amy; Więski, Kazimierz; Zelig, Emily M.; Pennings, Steven C.

    2015-01-01

    In general, community similarity is thought to decay with distance; however, this view may be complicated by the relative roles of different ecological processes at different geographical scales, and by the compositional perspective (e.g. species, functional group and phylogenetic lineage) used. Coastal salt marshes are widely distributed worldwide, but no studies have explicitly examined variation in salt marsh plant community composition across geographical scales, and from species, functional and phylogenetic perspectives. Based on studies in other ecosystems, we hypothesized that, in coastal salt marshes, community turnover would be more rapid at local versus larger geographical scales; and that community turnover patterns would diverge among compositional perspectives, with a greater distance decay at the species level than at the functional or phylogenetic levels. We tested these hypotheses in salt marshes of two regions: The southern Atlantic and Gulf Coasts of the United States. We examined the characteristics of plant community composition at each salt marsh site, how community similarity decayed with distance within individual salt marshes versus among sites in each region, and how community similarity differed among regions, using species, functional and phylogenetic perspectives. We found that results from the three compositional perspectives generally showed similar patterns: there was strong variation in community composition within individual salt marsh sites across elevation; in contrast, community similarity decayed with distance four to five orders of magnitude more slowly across sites within each region. Overall, community dissimilarity of salt marshes was lowest on the southern Atlantic Coast, intermediate on the Gulf Coast, and highest between the two regions. Our results indicated that local gradients are relatively more important than regional processes in structuring coastal salt marsh communities. Our results also suggested that in

  12. Packing, Scheduling and Covering Problems in a Game-Theoretic Perspective

    NASA Astrophysics Data System (ADS)

    Karlstrom, Leif

    Magma transport pathways through Earth's crust span 12--15 orders of magnitude in time and space, with unsteadiness at all scales. However emergent organization of this system is widespread, recorded by spatial loci of volcanism at the surface and large-scale, rapid outpourings of magma throughout the geologic record. This thesis explores several mechanisms for the organization and time evolution of magma transport, from the deep crust to the surface. A primary focus (Chapters 2--5) is the filling, stability and drainage of magma chambers, structures which function both as reservoirs feeding individual volcanic eruptions and as stalling points in the crust where magma accumulates and differentiation occurs. We show that magma chambers may dictate the spatio-temporal organization of magma rising through crust (Chapters 2--3), control the surface eruptive progression of extreme mantle melting events (Chapter 4), and actively set the size of calderas that form during shallow, crystal rich eruptions (Chapter 5). Each of these chapters explores variations on a hypothesis: interactions between magma chamber stresses and the rheology of surrounding crustal materials evolve during magma transport and this unsteady process helps determine the magnitude, location, and timing of surface eruptions. The last part of this thesis (Chapters 6--7) focuses on surface transport processes, the meandering of melt channels on the surface of glaciers and lava flows. We show that the meandering instability is a generic feature of flow over an erodable substrate, despite significantly different fluid characteristics and erosion mechanics.

  13. Fast algorithm for solving the Hankel/Toeplitz Structured Total Least Squares problem

    NASA Astrophysics Data System (ADS)

    Lemmerling, Philippe; Mastronardi, Nicola; van Huffel, Sabine

    2000-07-01

    The Structured Total Least Squares (STLS) problem is a natural extension of the Total Least Squares (TLS) problem when constraints on the matrix structure need to be imposed. Similar to the ordinary TLS approach, the STLS approach can be used to determine the parameter vector of a linear model, given some noisy measurements. In many signal processing applications, the imposition of this matrix structure constraint is necessary for obtaining Maximum Likelihood (ML) estimates of the parameter vectorE In this paper we consider the Toeplitz (Hankel) STLS problem (i.e., an STLS problem in which the Toeplitz (Hankel) structure needs to be preserved). A fast implementation of an algorithm for solving this frequently occurring STLS problem is proposed. The increased efficiency is obtained by exploiting the low displacement rank of the involved matrices and the sparsity of the associated generators. The fast implementation is compared to two other implementations of algorithms for solving the Toeplitz (Hankel) STLS problem. The comparison is carried out on a recently proposed speech compression scheme. The numerical results confirm the high efficiency of the newly proposed fast implementation: the straightforward implementations have a complexity of O((m+n)3) and O(m3) whereas the proposed implementation has a complexity of O(mn+n2).

  14. US EPA (Environmental Protection Agency) perspective on AOC (assimilable organic carbon) research as related to coliform colonization and compliance problems

    SciTech Connect

    Reasoner, D.J.; Rice, E.W.

    1989-01-01

    The biological stability of treated drinking water has become a major concern for water utilities. The U.S. E.P.A. is concerned from the perspective of coliform MCL compliance and remediation of coliform biofilm problems. The levels of readily assimilable nutrients present in treated water are affected by water treatment processes, but of greatest concern are those processes, such as ozonation, that cause increases in the levels of assimilable organic carbon (AOC) and therefore contribute to biological instability of the water. Thus, the combined use of ozonation (pre-oxidant) and a lower disinfectant residual as an approach to reducing disinfectant byproducts may result in increased bacterial growth, including coliforms, in the distribution system. Information is needed on: the AOC flux level that stimulate coliform growth in biofilm: the specific nutrients and concentrations that can stimulate growth of both coliforms and HPC; treatment strategies to reduce AOC levels and strategies to effectively control biofilm formation where AOC levels cannot be reduced.

  15. Outpatients' Perspectives on Problems and Needs Related to Female Genital Mutilation/Cutting: A Qualitative Study from Somaliland

    PubMed Central

    Fried, Sarah; Mahmoud Warsame, Amina; Berggren, Vanja; Isman, Elisabeth; Johansson, Annika

    2013-01-01

    Aim. To explore female outpatients' perspectives on problems related to female genital mutilation/cutting (FGM/C) and their views on information, care, and counseling. Setting. An FGM/C support center at a maternity clinic in Hargeisa, Somaliland. Methods. A qualitative, descriptive study, using content analysis of seven semistructured interviews with female outpatients. Results. All participants had been ignorant of the etiology of their FGM/C-related complications and hesitant to seek care. All had undergone infibulation but did not wish the same for their daughters. In recent years they had learnt through religious leaders and media campaigns that infibulation was unapproved by Islam. A less severe FGM/C type, “Sunna,” was more accepted; however, few could define what “Sunna” meant. Condemning and ridiculing attitudes against uncircumcised women prevailed in their community. Conclusions. New ideas and concepts related to FGM/C enter the common discourse in the Somali society while traditional norms and values still prevail. Religion was shown to have a strong impact on FGM/C practices and beliefs. Interventions aiming to raise awareness of health consequences of all types of FGM/C, as well as where to seek care for complications, are needed in Somaliland. Involvement of religious leaders in anti-FGM/C programs is essential. PMID:24151505

  16. Palaeo sea-level and ice-sheet databases: problems, strategies and perspectives

    NASA Astrophysics Data System (ADS)

    Rovere, Alessio; Düsterhus, André; Carlson, Anders; Barlow, Natasha; Bradwell, Tom; Dutton, Andrea; Gehrels, Roland; Hibbert, Fiona; Hijma, Marc; Horton, Benjamin; Klemann, Volker; Kopp, Robert; Sivan, Dorit; Tarasov, Lev; Törnqvist, Torbjorn

    2016-04-01

    Databases of palaeoclimate data have driven many major developments in understanding the Earth system. The measurement and interpretation of palaeo sea-level and ice-sheet data that form such databases pose considerable challenges to the scientific communities that use them for further analyses. In this paper, we build on the experience of the PALSEA (PALeo constraints on SEA level rise) community, which is a working group inside the PAGES (Past Global Changes) project, to describe the challenges and best strategies that can be adopted to build a self-consistent and standardised database of geological and geochemical data related to palaeo sea levels and ice sheets. Our aim in this paper is to identify key points that need attention and subsequent funding when undertaking the task of database creation. We conclude that any sea-level or ice-sheet database must be divided into three instances: i) measurement; ii) interpretation; iii) database creation. Measurement should include postion, age, description of geological features, and quantification of uncertainties. All must be described as objectively as possible. Interpretation can be subjective, but it should always include uncertainties and include all the possible interpretations, without unjustified a priori exclusions. We propose that, in the creation of a database, an approach based on Accessibility, Transparency, Trust, Availability, Continued updating, Completeness and Communication of content (ATTAC3) must be adopted. Also, it is essential to consider the community structure that creates and benefits of a database. We conclude that funding sources should consider to address not only the creation of original data in specific research-question oriented projects, but also include the possibility to use part of the funding for IT-related and database creation tasks, which are essential to guarantee accessibility and maintenance of the collected data.

  17. Exploring the views of people with mental health problems' on the concept of coercion: Towards a broader socio-ethical perspective.

    PubMed

    Norvoll, Reidun; Pedersen, Reidar

    2016-05-01

    In mental health care, coercion is a controversial issue that has led to much debate and research on its nature and use. Yet, few previous studies have explicitly explored the views on the concept of coercion among people with first-hand experiences of being coerced. This study includes semi-structured focus-groups and individual interviews with 24 participants who had various mental health problems and experiences with coercion. Data were collected in 2012-2013 in three regions of Norway and analysed by a thematic content analysis. Findings show that participants had wide-ranging accounts of coercion, including formal and informal coercion across health- and welfare services. They emphasised that using coercion reflects the mental health system's tendency to rely on coercion and the lack of voluntary services and treatment methods that are more helpful. Other core characteristics of coercion were deprivation of freedom, power relations, in terms of powerlessness and 'counter-power,' and coercion as existential and social life events. Participants' views are consistent with prevailing theories of coercion and research on perceived coercion. However, this study demonstrates a need for broader existential and socio-ethical perspectives on coercion that are intertwined with treatment and care systems in research and practice. Implications for mental health policy and services are discussed.

  18. Exploring the views of people with mental health problems' on the concept of coercion: Towards a broader socio-ethical perspective.

    PubMed

    Norvoll, Reidun; Pedersen, Reidar

    2016-05-01

    In mental health care, coercion is a controversial issue that has led to much debate and research on its nature and use. Yet, few previous studies have explicitly explored the views on the concept of coercion among people with first-hand experiences of being coerced. This study includes semi-structured focus-groups and individual interviews with 24 participants who had various mental health problems and experiences with coercion. Data were collected in 2012-2013 in three regions of Norway and analysed by a thematic content analysis. Findings show that participants had wide-ranging accounts of coercion, including formal and informal coercion across health- and welfare services. They emphasised that using coercion reflects the mental health system's tendency to rely on coercion and the lack of voluntary services and treatment methods that are more helpful. Other core characteristics of coercion were deprivation of freedom, power relations, in terms of powerlessness and 'counter-power,' and coercion as existential and social life events. Participants' views are consistent with prevailing theories of coercion and research on perceived coercion. However, this study demonstrates a need for broader existential and socio-ethical perspectives on coercion that are intertwined with treatment and care systems in research and practice. Implications for mental health policy and services are discussed. PMID:27054304

  19. Advances in Rosetta structure prediction for difficult molecular-replacement problems

    SciTech Connect

    DiMaio, Frank

    2013-11-01

    Modeling advances using Rosetta structure prediction to aid in solving difficult molecular-replacement problems are discussed. Recent work has shown the effectiveness of structure-prediction methods in solving difficult molecular-replacement problems. The Rosetta protein structure modeling suite can aid in the solution of difficult molecular-replacement problems using templates from 15 to 25% sequence identity; Rosetta refinement guided by noisy density has consistently led to solved structures where other methods fail. In this paper, an overview of the use of Rosetta for these difficult molecular-replacement problems is provided and new modeling developments that further improve model quality are described. Several variations to the method are introduced that significantly reduce the time needed to generate a model and the sampling required to improve the starting template. The improvements are benchmarked on a set of nine difficult cases and it is shown that this improved method obtains consistently better models in less running time. Finally, strategies for best using Rosetta to solve difficult molecular-replacement problems are presented and future directions for the role of structure-prediction methods in crystallography are discussed.

  20. Perspective: Structural dynamics in condensed matter mapped by femtosecond x-ray diffraction

    SciTech Connect

    Elsaesser, T.; Woerner, M.

    2014-01-14

    Ultrashort soft and hard x-ray pulses are sensitive probes of structural dynamics on the picometer length and femtosecond time scales of electronic and atomic motions. Recent progress in generating such pulses has initiated new directions of condensed matter research, exploiting a variety of x-ray absorption, scattering, and diffraction methods to probe photoinduced structural dynamics. Atomic motion, changes of local structure and long-range order, as well as correlated electron motion and charge transfer have been resolved in space and time, providing a most direct access to the physical mechanisms and interactions driving reversible and irreversible changes of structure. This perspective combines an overview of recent advances in femtosecond x-ray diffraction with a discussion on ongoing and future developments.

  1. ATLAS, an integrated structural analysis and design system. Volume 5: System demonstration problems

    NASA Technical Reports Server (NTRS)

    Samuel, R. A. (Editor)

    1979-01-01

    One of a series of documents describing the ATLAS System for structural analysis and design is presented. A set of problems is described that demonstrate the various analysis and design capabilities of the ATLAS System proper as well as capabilities available by means of interfaces with other computer programs. Input data and results for each demonstration problem are discussed. Results are compared to theoretical solutions or experimental data where possible. Listings of all input data are included.

  2. Approximate analysis for repeated eigenvalue problems with applications to controls-structure integrated design

    NASA Technical Reports Server (NTRS)

    Kenny, Sean P.; Hou, Gene J. W.

    1994-01-01

    A method for eigenvalue and eigenvector approximate analysis for the case of repeated eigenvalues with distinct first derivatives is presented. The approximate analysis method developed involves a reparameterization of the multivariable structural eigenvalue problem in terms of a single positive-valued parameter. The resulting equations yield first-order approximations to changes in the eigenvalues and the eigenvectors associated with the repeated eigenvalue problem. This work also presents a numerical technique that facilitates the definition of an eigenvector derivative for the case of repeated eigenvalues with repeated eigenvalue derivatives (of all orders). Examples are given which demonstrate the application of such equations for sensitivity and approximate analysis. Emphasis is placed on the application of sensitivity analysis to large-scale structural and controls-structures optimization problems.

  3. Psychosocial Problems Among Truant Youth: A Multi-Group, Exploratory Structural Equation Modeling Analysis

    PubMed Central

    Dembo, Richard; Briones-Robinson, Rhissa; Barrett, Kimberly; Winters, Ken C.; Ungaro, Rocio; Karas, Lora; Wareham, Jennifer; Belenko, Steven

    2012-01-01

    Truant youth represent a critical group needing problem-oriented research and involvement in effective services. The limited number of studies on the psychosocial functioning of truant youths have focused on one or a few problem areas, rather than examining co-morbid problem behaviors. The present study addresses the need to examine the interrelationships of multiple domains of psychosocial functioning, including substance involvement, mental health, and delinquency, among truant youth. Exploratory structural equation modeling on baseline data collected on 219 truant youths identified two major factors reflecting psychosocial functioning, and found the factor structure was similar across major sociodemographic subgroups. Further analyses supported the validity of the factor structure. The research and service delivery implications of the findings are discussed. PMID:23243383

  4. Perspective - Open problems in earth surface dynamics require innovative new methodologies from graph theory and non-linear analysis

    NASA Astrophysics Data System (ADS)

    Foufoula-Georgiou, Efi; Schwenk, Jon; Tejedor, Alejandro

    2015-04-01

    Are the dynamics of meandering rivers non-linear? What information does the shape of an oxbow lake carry about its forming process? How to characterize self-dissimilar landscapes carrying the signature of larger-scale geologic or tectonic controls? Do we have proper frameworks for quantifying the topology and dynamics of deltaic systems? What can the structural complexity of river networks (erosional and depositional) reveal about their vulnerability and response to change? Can the structure and dynamics of river networks reveal potential hotspots of geomorphic change? All of the above problems are at the heart of understanding landscape evolution, relating process to structure and form, and developing methodologies for inferring how a system might respond to future changes. We argue that a new surge of rigorous methodologies is needed to address these problems. The innovations introduced herein are: (1) gradual wavelet reconstruction for depicting threshold nonlinearity (due to cutoffs) versus inherent nonlinearity (due to underlying dynamics) in river meandering, (2) graph theory for studying the topology and dynamics of deltaic river networks and their response to change, and (3) Lagrangian approaches combined with topology and non-linear dynamics for inferring sediment-driven hotspots of geomorphic change.

  5. A computational algorithm for a disturbance rejection problem in structural acoustics

    SciTech Connect

    Hendrickson, E.

    1994-12-31

    We consider a disturbance rejection problem for an optimal control problem arising in structural acoustics. The solution to the control problem with unbounded control action involves the solution to an algebraic Riccati equation as well as an associated linear, nonhomogeneous differential equation. The goal is to construct a numerical algorithm based on the FEM for the computations of solutions to associated matrix algebraic Riccati equations. The Riccati-based feedback control will be used to minimize the effect of the disturbance for a given performance index.

  6. Numerical investigation of transport mechanism in four-body problem using Lagrangian coherent structure

    NASA Astrophysics Data System (ADS)

    Qi, Rui; Huang, Biao

    2016-01-01

    Transport mechanism is critical for understanding natural phenomena in the solar system and is beneficial to space mission design. In this study, transport mechanism in the bicircular four-body problem is numerically explored by using Lagrangian coherent structure (LCS), a tool widely used for identifying transport barriers in fluid flow. First, equations of motion of the bicircular problem are derived and five topology configurations of forbidden region are presented. Then, definition and computational method of LCS are introduced. Finally, properties of LCS which are useful for revealing transport mechanism in the four-body problem are numerically investigated.

  7. The Transition to Preschool: A Problem or an Opportunity for Children? A Sociological Perspective in the Context of a "Split System"

    ERIC Educational Resources Information Center

    Amerijckx, Gaëlle; Humblet, Perrine C.

    2015-01-01

    This article discusses the central issue of the transition to preschool. Individual semi-structured interviews with school professionals and parents in the Brussels region revealed that this issue is crucial for the well-being of young children, from both an educational and a social perspective. We discovered that the education system works under…

  8. Emotional and Behavioral Problems among Impoverished Kenyan Youth: Factor Structure and Sex-Differences

    PubMed Central

    Harder, Valerie S.; Mutiso, Victoria N.; Khasakhala, Lincoln I.; Burke, Heather M.; Rettew, David C.; Ivanova, Masha Y.; Ndetei, David M.

    2014-01-01

    Data on youth emotional and behavioral problems from societies in Sub-Saharan Africa are lacking. This may be due to the fact that few youth mental health assessments have been tested for construct validity of syndrome structure across multicultural societies that include developing countries, and almost none have been tested in Sub-Saharan Africa. The Youth Self-Report (YSR), for example, has shown great consistency of its syndrome structure across many cultures, yet data from only one developing country in Sub-Saharan Africa have been included. In this study, we test the factor structure of YSR syndromes among Kenyan youth ages 11–18 years from an informal settlement in Nairobi, Kenya and examine sex-differences in levels of emotional and behavioral problems. We find the eight syndrome structure of the YSR to fit these data well (Root Mean Square Error of Approximation=.049). While Kenyan girls have significantly higher internalizing (Anxious/Depressed, Withdrawn/Depressed, Somatic) problem scores than boys, these differences are of similar magnitude to published multicultural findings. The results support the generalizability of the YSR syndrome structure to Kenyan youth and are in line with multicultural findings supporting the YSR as an assessment of emotional and behavioral problems in diverse societies. PMID:25419046

  9. Problems in functioning from the patient perspective using the International Classification of Functioning, Disability and Health (ICF) as a reference.

    PubMed

    Gradinger, Felix; Köhler, Barbara; Khatami, Ramin; Mathis, Johannes; Cieza, Alarcos; Bassetti, Claudio

    2011-03-01

    We conducted a qualitative, multicenter study using a focus group design to explore the lived experiences of persons with any kind of primary sleep disorder with regard to functioning and contextual factors using six open-ended questions related to the International Classification of Functioning, Disability and Health (ICF) components. We classified the results using the ICF as a frame of reference. We identified the meaningful concepts within the transcribed data and then linked them to ICF categories according to established linking rules. The six focus groups with 27 participants yielded a total of 6986 relevant concepts, which were linked to a total of 168 different second-level ICF categories. From the patient perspective, the ICF components: (1) Body Functions; (2) Activities & Participation; and (3) Environmental Factors were equally represented; while (4) Body Structures appeared poignantly less frequently. Out of the total number of concepts, 1843 concepts (26%) were assigned to the ICF component Personal Factors, which is not yet classified but could indicate important aspects of resource management and strategy development of those who have a sleep disorder. Therefore, treatment of patients with sleep disorders must not be limited to anatomical and (patho-)physiological changes, but should also consider a more comprehensive view that includes patient's demands, strategies and resources in daily life and the contextual circumstances surrounding the individual.

  10. Understanding ill-structured engineering ethics problems through a collaborative learning and argument visualization approach.

    PubMed

    Hoffmann, Michael; Borenstein, Jason

    2014-03-01

    As a committee of the National Academy of Engineering recognized, ethics education should foster the ability of students to analyze complex decision situations and ill-structured problems. Building on the NAE's insights, we report about an innovative teaching approach that has two main features: first, it places the emphasis on deliberation and on self-directed, problem-based learning in small groups of students; and second, it focuses on understanding ill-structured problems. The first innovation is motivated by an abundance of scholarly research that supports the value of deliberative learning practices. The second results from a critique of the traditional case-study approach in engineering ethics. A key problem with standard cases is that they are usually described in such a fashion that renders the ethical problem as being too obvious and simplistic. The practitioner, by contrast, may face problems that are ill-structured. In the collaborative learning environment described here, groups of students use interactive and web-based argument visualization software called "AGORA-net: Participate - Deliberate!". The function of the software is to structure communication and problem solving in small groups. Students are confronted with the task of identifying possible stakeholder positions and reconstructing their legitimacy by constructing justifications for these positions in the form of graphically represented argument maps. The argument maps are then presented in class so that these stakeholder positions and their respective justifications become visible and can be brought into a reasoned dialogue. Argument mapping provides an opportunity for students to collaborate in teams and to develop critical thinking and argumentation skills.

  11. Boundary velocity method for continuum shape sensitivity of nonlinear fluid-structure interaction problems

    NASA Astrophysics Data System (ADS)

    Liu, Shaobin; Canfield, Robert A.

    2013-07-01

    A Continuum Sensitivity Equation (CSE) method was developed in local derivative form for fluid-structure shape design problems. The boundary velocity method was used to derive the continuum sensitivity equations and sensitivity boundary conditions in local derivative form for a built-up joined beam structure under transient aerodynamic loads. For nonlinear problems, when the Newton-Raphson method is used, the tangent stiffness matrix yields the desired sensitivity coefficient matrix for solving the linear sensitivity equations in the Galerkin finite element formulation. For built-up structures with strain discontinuity, the local sensitivity variables are not continuous at the joints, requiring special treatment to assemble the elemental local sensitivities and the generalized force vector. The coupled fluid-structure physics and continuum sensitivity equations for gust response of a nonlinear joined beam with an airfoil model were posed and solved. The results were compared to the results obtained by finite difference (FD) method.

  12. Reviewing the impact of problem structure on planning: a software tool for analyzing tower tasks.

    PubMed

    Kaller, Christoph P; Rahm, Benjamin; Köstering, Lena; Unterrainer, Josef M

    2011-01-01

    Cognitive, clinical, and neuroimaging studies on planning abilities most frequently implement the Tower of London task or one of its variants. Yet, cumulating evidence from a series of experiments suggests that the commonly used approximation of problem difficulty in terms of the minimum number of moves for goal attainment is too coarse a measure for the underlying cognitive operations, and in some cases may be even misleading. Rather, problem difficulty can be more specifically characterized by a set of structural task parameters such as the number and nature of optimal and suboptimal solution paths, the required search depths, the patterns of intermediate and goal moves, goal hierarchies and the associated degree of ambiguity in the sequential ordering of goal moves. First applications in developmental and patient studies have proven fruitful in targeting fundamental alterations of planning abilities in healthy and clinical conditions. In addition, recent evidence from neuroimaging shows that manipulations of problem structure relate to separate cognitive and neural processes and are accompanied by dissociable brain activation patterns. Here, we briefly review these structural problem parameters and the concepts behind. As controlling for task parameters and selecting a balanced problem set is a complex and error-prone endeavor, we further present TowerTool, a software solution that allows easy access to in-depth analysis of the problem structure of widely used planning tasks like the Tower of London, the Tower of Hanoi, and their variants. Thereby, we hope to encourage and facilitate the implementation of structurally balanced task sets in future studies on planning and to promote transfer between the cognitive, developmental, and clinical neurosciences. PMID:20723568

  13. Relation between parent psychiatric symptoms and youth problems: moderation through family structure and youth gender.

    PubMed

    Schleider, Jessica L; Chorpita, Bruce F; Weisz, John R

    2014-02-01

    Links between parents' psychiatric symptoms and their children's behavioral and emotional problems have been widely documented in previous research, and the search for moderators of this association has begun. However, family structure (single versus dual-parent households) has received little attention as a potential moderator, despite indirect evidence that risk may be elevated in single-parent homes. Two other candidate moderators-youth gender and age-have been tested directly, but with inconsistent findings across studies, perhaps in part because studies have differed in whether they used youth clinical samples and in which informants (parents vs. youths) reported on youth problems. In the present study, we examined these three candidate moderators using a sample of exclusively clinic-referred youths (N = 333, 34 % girls, aged 7-14,) and assessing youth problems through both parent- and youth-reports. Both family structure and youth gender emerged as robust moderators across parent and youth informants. Parent symptoms were associated with youth internalizing and externalizing problems in single-parent but not dual-parent homes; and parent symptoms were associated with youth internalizing problems among boys, but not girls. The moderator findings suggest that the risks associated with parent psychopathology may not be uniform but may depend, in part, on family structure and youth gender.

  14. Time dependent adjoint-based optimization for coupled fluid-structure problems

    NASA Astrophysics Data System (ADS)

    Mishra, Asitav; Mani, Karthik; Mavriplis, Dimitri; Sitaraman, Jay

    2015-07-01

    A formulation for sensitivity analysis of fully coupled time-dependent aeroelastic problems is given in this paper. Both forward sensitivity and adjoint sensitivity formulations are derived that correspond to analogues of the fully coupled non-linear aeroelastic analysis problem. Both sensitivity analysis formulations make use of the same iterative disciplinary solution techniques used for analysis, and make use of an analogous coupling strategy. The information passed between fluid and structural solvers is dimensionally equivalent in all cases, enabling the use of the same data structures for analysis, forward and adjoint problems. The fully coupled adjoint formulation is then used to perform rotor blade design optimization for a four bladed HART2 rotor in hover conditions started impulsively from rest. The effect of time step size and mesh resolution on optimization results is investigated.

  15. Lagrangian heuristic method for the wireless sensor network design problem in railway structural health monitoring

    NASA Astrophysics Data System (ADS)

    Hada, Akio; Soga, Kenichi; Liu, Ruoshui; Wassell, Ian J.

    2012-04-01

    In this paper, we study a design method for minimizing the total cost of a wireless sensor network (WSN) used for health monitoring of railway structures. First, we present the problem, that is to simultaneously determine the number of relays and their deployment locations, the transmission power level for each sensor and relay, and the routes for transferring sensor data to a gateway using multi-hop wireless communication. Second, we formulate this task as a mathematical programming problem, and to solve this problem, we propose a near optimal algorithm based on the Lagrangian heuristic method. Finally, we verify the effectiveness of our algorithm through computational experiments carried out using data acquired from a real WSN used for railway structural health monitoring.

  16. Effective dimensional reduction algorithm for eigenvalue problems for thin elastic structures: A paradigm in three dimensions

    PubMed Central

    Ovtchinnikov, Evgueni E.; Xanthis, Leonidas S.

    2000-01-01

    We present a methodology for the efficient numerical solution of eigenvalue problems of full three-dimensional elasticity for thin elastic structures, such as shells, plates and rods of arbitrary geometry, discretized by the finite element method. Such problems are solved by iterative methods, which, however, are known to suffer from slow convergence or even convergence failure, when the thickness is small. In this paper we show an effective way of resolving this difficulty by invoking a special preconditioning technique associated with the effective dimensional reduction algorithm (EDRA). As an example, we present an algorithm for computing the minimal eigenvalue of a thin elastic plate and we show both theoretically and numerically that it is robust with respect to both the thickness and discretization parameters, i.e. the convergence does not deteriorate with diminishing thickness or mesh refinement. This robustness is sine qua non for the efficient computation of large-scale eigenvalue problems for thin elastic structures. PMID:10655469

  17. Developing Ill-Structured Problem-Solving Skills through Wilderness Education

    ERIC Educational Resources Information Center

    Collins, Rachel H.; Sibthorp, Jim; Gookin, John

    2016-01-01

    In a society that is becoming more dynamic, complex, and diverse, the ability to solve ill-structured problems (ISPs) has become an increasingly critical skill. Students who enter adult roles with the cognitive skills to address ISPs will be better able to assume roles in the emerging economies. Opportunities to develop and practice these skills…

  18. Epistemological Beliefs and Ill-Structured Problem-Solving in Solo and Paired Contexts

    ERIC Educational Resources Information Center

    Angeli, Charoula; Valanides, Nicos

    2012-01-01

    A mixed-method exploratory approach was employed to examine the relationship between epistemological beliefs and quality of thinking when participants first thought about an ill-structured problem alone, and then with another person in a dyad. The results showed that there was not a systematic connection between epistemological beliefs and…

  19. Parallel-vector solution of large-scale structural analysis problems on supercomputers

    NASA Technical Reports Server (NTRS)

    Storaasli, Olaf O.; Nguyen, Duc T.; Agarwal, Tarun K.

    1989-01-01

    A direct linear equation solution method based on the Choleski factorization procedure is presented which exploits both parallel and vector features of supercomputers. The new equation solver is described, and its performance is evaluated by solving structural analysis problems on three high-performance computers. The method has been implemented using Force, a generic parallel FORTRAN language.

  20. Solving the Problems of Iowa Food Deserts: Food Insecurity and Civic Structure

    ERIC Educational Resources Information Center

    Morton, Lois Wright; Bitto, Ella Annette; Oakland, Mary Jane; Sand, Mary

    2005-01-01

    Rural regions include places where food sources are not evenly distributed, leading to areas of concentration and food desert--places where few or no grocery stores exist. Individuals are hypothesized to depend on personal connections and the civic structure of where they live to help them solve the problem of food insecurity. We find that…

  1. Family Structure and Its Effect on Behavioral and Emotional Problems in Young Adolescents.

    ERIC Educational Resources Information Center

    Lee, Valerie E.; And Others

    This study gauged the effects of divorce and remarriage on the emotional adjustment of young adolescents. Using a large and nationally representative sample of eighth graders, the study investigated the incidence of school-related emotional and behavioral problems associated with variation in family structure. Data were collected on: (1) family…

  2. Vocational Education in France--Structural Problems and Present Efforts towards Reform. CEDEFOP Document.

    ERIC Educational Resources Information Center

    Koch, Richard

    The structural problems present in vocational education in France and reform efforts under way to solve them were studied. Eighteen experts from government, science, and industry were interviewed, and statistics and other relevant publications were analyzed. The development of the French initial training system was outlined, and trends in…

  3. Case Designs for Ill-Structured Problems: Analysis and Implications for Practice

    ERIC Educational Resources Information Center

    Dabbagh, Nada; Blijd, Cecily Williams

    2009-01-01

    This study is a third in a series of studies that examined students' information seeking and problem solving behaviors while interacting with one of two types of web-based representations of an ill-structured instructional design case: hierarchical (tree-like) and heterarchical (network-like). A Java program was used to track students' hypermedia…

  4. Structured Medication Review to Improve Pharmacotherapy in People with Intellectual Disability and Behavioural Problems

    ERIC Educational Resources Information Center

    Scheifes, Arlette; Egberts, Toine C. G.; Stolker, Joost Jan; Nijman, Henk. L. I.; Heerdink, Eibert R.

    2016-01-01

    Background: Polypharmacy and chronic drug use are common in people with intellectual disability and behavioural problems, although evidence of effectiveness and safety in this population is lacking. This study examined the effects of a structured medication review and aimed to improve pharmacotherapy in inpatients with intellectual disability.…

  5. The analytic solution of the structural analysis problem and its use in structural synthesis

    NASA Astrophysics Data System (ADS)

    Fuchs, M. B.

    An overview is presented of the analytic expressions for the inverse of the stiffness matrix, the nodal displacements, and the internal forces in linear elastic redundant structures. The inverse of the stiffness matrix and the nodal displacements are obtained using Binet and Cauchy's theorem on the product of compound matrices. The formula for the internal forces is derived from the principles of structural mechanics. This approach is shown to apply to all framed structures via the unimodal stiffnesses of its elements. Approximate models are constructed which are exact at preselected points along a line in the analysis space. An argument is also made for the use of multilinear polynomials as an alternative to Taylor expansion-based approximations.

  6. Hybrid preconditioning for iterative diagonalization of ill-conditioned generalized eigenvalue problems in electronic structure calculations

    SciTech Connect

    Cai, Yunfeng; Bai, Zhaojun; Pask, John E.; Sukumar, N.

    2013-12-15

    The iterative diagonalization of a sequence of large ill-conditioned generalized eigenvalue problems is a computational bottleneck in quantum mechanical methods employing a nonorthogonal basis for ab initio electronic structure calculations. We propose a hybrid preconditioning scheme to effectively combine global and locally accelerated preconditioners for rapid iterative diagonalization of such eigenvalue problems. In partition-of-unity finite-element (PUFE) pseudopotential density-functional calculations, employing a nonorthogonal basis, we show that the hybrid preconditioned block steepest descent method is a cost-effective eigensolver, outperforming current state-of-the-art global preconditioning schemes, and comparably efficient for the ill-conditioned generalized eigenvalue problems produced by PUFE as the locally optimal block preconditioned conjugate-gradient method for the well-conditioned standard eigenvalue problems produced by planewave methods.

  7. The reduced order model problem in distributed parameter systems adaptive identification and control. [large space structures

    NASA Technical Reports Server (NTRS)

    Johnson, C. R., Jr.; Lawrence, D.

    1981-01-01

    The basic assumption that a large space structure can be decoupled preceding the application of reduced order active control was considered and alternative solutions to the control of such structures (in contrast to the strict modal control) were investigated. The transfer function matrix from the actuators to the sensors was deemed to be a reasonable candidate. More refined models from multivariable systems theory were studied and recent results in the multivariable control field were compared with respect to theoretical deficiencies and likely problems in application to large space structures.

  8. Response to Masafumi Ogawa, "Music Teacher Education in Japan: Structure, Problems, and Perspectives"

    ERIC Educational Resources Information Center

    Hornbach, Christina

    2004-01-01

    Masafumi Ogawa cares deeply about improving music teacher education and has grave concerns about Japan's current music education and teacher training system. He notes reduced instructional time, cuts in teaching positions, and classroom management issues resulting in the devaluing of music education by administrators, students, and the general…

  9. A molecular picture of the problems in ensuring structural purity of tazofelone

    NASA Astrophysics Data System (ADS)

    Price, Louise S.; McMahon, Jennifer A.; Lingireddy, Sreenivas R.; Lau, Suk-Fai; Diseroad, Benjamin A.; Price, Sarah L.; Reutzel-Edens, Susan M.

    2014-12-01

    Almost twenty years after the crystal polymorphism of tazofelone was first studied at Lilly, the compound was revisited by calculating the crystal energy landscape and complementing the calculations with experimental work for calibration purposes. The crystal structure prediction study confirmed the stability of racemic form II (RCII) and showed that the racemic compound had greater potential for polymorphism than the single enantiomer. The seeding experiment that has previously been shown to produce a racemic solid solution (SS) correlates with the isostructurality between some low energy racemic structures and the enantiopure form. Other low energy structures have the same layer structure as both racemic polymorphs and the newly-discovered, but closely related, polymorph RCIII, which accounts for the difficulty in obtaining phase pure samples of the metastable RCI and RCIII and the problems of structural purity evidenced by streaked diffraction spots for RCI-III in the single crystal diffraction. This molecular picture of the problems in ensuring structural purity in the layer structure polymorphs of tazofelone not only explains the crystal dependent thermochemistry measurements of tazofelone, but also shows the value of combining a range of experimental and computational techniques to investigate the organic solid state.

  10. Designing and Implementing a Case-Based Learning Environment for Enhancing Ill-Structured Problem Solving: Classroom Management Problems for Prospective Teachers

    ERIC Educational Resources Information Center

    Choi, Ikseon; Lee, Kyunghwa

    2009-01-01

    This design-based research study is aimed at two goals: (1) developing a feasible case-based instructional model that could enhance college students' ill-structured problem solving abilities, while (2) implementing the model to improve teacher education students' real-world problem solving abilities to deal with dilemmas faced by practicing…

  11. How much will China weigh? Perspectives from consumption structure and technology development.

    PubMed

    Xu, Ming; Zhang, Tianzhu; Allenby, Braden

    2008-06-01

    Current patterns and future possibilities of China's material metabolism are evaluated from perspectives of consumption structure change and technology development using the approach of input-output modeling to integrate ecological and economic systems. A physical input monetary output (PIMO) model is created and is applied to the Chinese economy with 43 sectors and 25 material categories. A set of scenarios, five exploring aspects of consumption structure change and three doing the same for technology development, is analyzed to quantitatively predict China's future possible material metabolism patterns in 2010. The results provide a foundation for quantitative studies of resource consumption and waste generation in China, which given its increasing pivotal role in manufacturing is also helpful for research on the material metabolism of the entire world. PMID:18589961

  12. Solvers for large-displacement fluid structure interaction problems: segregated versus monolithic approaches

    NASA Astrophysics Data System (ADS)

    Heil, Matthias; Hazel, Andrew L.; Boyle, Jonathan

    2008-12-01

    We compare the relative performance of monolithic and segregated (partitioned) solvers for large- displacement fluid structure interaction (FSI) problems within the framework of oomph-lib, the object-oriented multi-physics finite-element library, available as open-source software at http://www.oomph-lib.org . Monolithic solvers are widely acknowledged to be more robust than their segregated counterparts, but are believed to be too expensive for use in large-scale problems. We demonstrate that monolithic solvers are competitive even for problems in which the fluid solid coupling is weak and, hence, the segregated solvers converge within a moderate number of iterations. The efficient monolithic solution of large-scale FSI problems requires the development of preconditioners for the iterative solution of the linear systems that arise during the solution of the monolithically coupled fluid and solid equations by Newton’s method. We demonstrate that recent improvements to oomph-lib’s FSI preconditioner result in mesh-independent convergence rates under uniform and non-uniform (adaptive) mesh refinement, and explore its performance in a number of two- and three-dimensional test problems involving the interaction of finite-Reynolds-number flows with shell and beam structures, as well as finite-thickness solids.

  13. Analytical solution to a fracture problem in a tough layered structure

    NASA Astrophysics Data System (ADS)

    Hamamoto, Yukari; Okumura, Ko

    2008-08-01

    Nacre causes the shining beauty of pearl due to its remarkable layered structure, which is also strong. We reconsider a simplified layered model of nacre proposed previously [Okumura and de Gennes, Eur. Phys. J. E 4, 121 (2001)] and obtain an analytical solution to a fundamental crack problem. The result asserts that the fracture toughness is enhanced due to a large displacement around the crack tip (even if the crack-tip stress is not reduced). The derivation offers ideas for solving a number of boundary problems for partial differential equations important in many fields.

  14. Solving the structural inverse gravity problem by the modified gradient methods

    NASA Astrophysics Data System (ADS)

    Martyshko, P. S.; Akimova, E. N.; Misilov, V. E.

    2016-09-01

    New methods for solving the three-dimensional inverse gravity problem in the class of contact surfaces are described. Based on the approach previously suggested by the authors, new algorithms are developed. Application of these algorithms significantly reduces the number of the iterations and computing time compared to the previous ones. The algorithms have been numerically implemented on the multicore processor. The example of solving the structural inverse gravity problem for a model of four-layer medium (with the use of gravity field measurements) is constructed.

  15. Two Point Exponential Approximation Method for structural optimization of problems with frequency constraints

    NASA Technical Reports Server (NTRS)

    Fadel, G. M.

    1991-01-01

    The point exponential approximation method was introduced by Fadel et al. (Fadel, 1990), and tested on structural optimization problems with stress and displacement constraints. The reports in earlier papers were promising, and the method, which consists of correcting Taylor series approximations using previous design history, is tested in this paper on optimization problems with frequency constraints. The aim of the research is to verify the robustness and speed of convergence of the two point exponential approximation method when highly non-linear constraints are used.

  16. Exploiting special problem structure when reliably investigating the solution of systems of IVPs and DDEs

    NASA Astrophysics Data System (ADS)

    Enright, W. H.

    2016-06-01

    In recent years we have developed a class of reliable order p methods for the approximate solution of general systems of initial value problems (IVPs) and delay differential equations (DDEs). In the theoretical analysis of these methods we have identified several trade-offs that do arise and have to be addressed when applying these methods to problems that exhibit special structure. Similar trade-offs also arise when one is concerned with investigating other important properties of the solutions. We will give examples of such trade-offs that arise when investigating the sensitivities of the solutions, and when very accurate approximate solutions are required.

  17. Numerical Study of the Structure of Metastable Configurations for the Thomson Problem

    NASA Astrophysics Data System (ADS)

    Bondarenko, A. N.; Bugueva, T. V.; Kozinkin, L. A.

    2016-05-01

    A numerical method is proposed for solving the Thomson problem - finding stable positions for a system of N point charges distributed on a sphere that minimize the potential energy of the system. The behavior of this system is essentially nonlinear, and the number of metastable structures grows exponentially with N. This makes the problem of finding all stable configurations extremely difficult. The results of testing of the developed algorithm and of numerical study of the properties of the local potential energy minima for a system of point charges are presented.

  18. Investigating information-processing performance of different command team structures in the NATO Problem Space.

    PubMed

    Stanton, Neville A; Rothrock, Ling; Harvey, Catherine; Sorensen, Linda

    2015-01-01

    The structure of command teams is a significant factor on their communications and ability to process, and act upon, information. The NATO Problem Space was used in this study to represent three of the main dimensions in the battle-space environment: familiarity, rate of change, and strength of information position. Results show that the five common team structures (chain, Y, circle, wheel and all-connected) did not generally perform as predicted in team literature. Findings suggest that under dynamic and highly variable conditions, high levels of synchronisation and trust should be present. On the other hand, synchronisation and trust are less important in hierarchical, highly centralised structures, because team members are more willing to accept the authority of a single leader and this tight control ensures that these teams can perform well as long as the Problem Space is familiar, information is explicit and the environment does not change. Practitioner Summary: Some types of team structures are better suited to particular constraints of the battle-space than others. This research has shown that the much touted all-connected structure is often the worst performing structure and that the traditional hierarchy of command and control has much merit in the digital information age. PMID:25992491

  19. Investigating information-processing performance of different command team structures in the NATO Problem Space.

    PubMed

    Stanton, Neville A; Rothrock, Ling; Harvey, Catherine; Sorensen, Linda

    2015-01-01

    The structure of command teams is a significant factor on their communications and ability to process, and act upon, information. The NATO Problem Space was used in this study to represent three of the main dimensions in the battle-space environment: familiarity, rate of change, and strength of information position. Results show that the five common team structures (chain, Y, circle, wheel and all-connected) did not generally perform as predicted in team literature. Findings suggest that under dynamic and highly variable conditions, high levels of synchronisation and trust should be present. On the other hand, synchronisation and trust are less important in hierarchical, highly centralised structures, because team members are more willing to accept the authority of a single leader and this tight control ensures that these teams can perform well as long as the Problem Space is familiar, information is explicit and the environment does not change. Practitioner Summary: Some types of team structures are better suited to particular constraints of the battle-space than others. This research has shown that the much touted all-connected structure is often the worst performing structure and that the traditional hierarchy of command and control has much merit in the digital information age.

  20. Correlations among knowledge structures, force concept inventory, and problem-solving behaviors

    NASA Astrophysics Data System (ADS)

    Malone, Kathy L.

    2008-12-01

    The modeling instruction pedagogy for the teaching of physics has been proven to be quite effective at increasing the conceptual understanding and problem-solving abilities of students to a much greater extent than that of nonmodeling students. Little research has been conducted concerning the cognitive and metacognitive skills that modeling students develop that allow for these increases. Two studies were designed to answer the following question: In what ways do the knowledge structures, metacognitive skills, and problem-solving abilities differ between modeling and nonmodeling students? In study 1, the knowledge structures developed by two groups of high school physics students taught using differing pedagogies (modeling instruction in physics and traditional methods) were determined using a card-sort task. The student’s knowledge structures were then correlated with the scores they obtained on two measures: the force concept inventory (FCI) and a problem-solving task (PS task) developed for this study. The modeling students had a more expertlike knowledge structure, while the nonmodeling students produced structures that were novicelike. In addition, the expert score correlated highly with performance on both the FCI and PS task scores demonstrating that a higher expert score predicted a higher value on each of these measures while a higher surface feature score predicted a lower score on both of these measures. In study 2, a verbal protocol design allowed for a detailed study of the problem-solving and metacognitive skills utilized by the two groups. It was determined that the skills utilized by the modeling instruction students were more expertlike. In addition, the modeling students produced significantly fewer physics errors while catching and repairing a greater percentage of their errors.

  1. Parallel-vector computation for structural analysis and nonlinear unconstrained optimization problems

    NASA Technical Reports Server (NTRS)

    Nguyen, Duc T.

    1990-01-01

    Practical engineering application can often be formulated in the form of a constrained optimization problem. There are several solution algorithms for solving a constrained optimization problem. One approach is to convert a constrained problem into a series of unconstrained problems. Furthermore, unconstrained solution algorithms can be used as part of the constrained solution algorithms. Structural optimization is an iterative process where one starts with an initial design, a finite element structure analysis is then performed to calculate the response of the system (such as displacements, stresses, eigenvalues, etc.). Based upon the sensitivity information on the objective and constraint functions, an optimizer such as ADS or IDESIGN, can be used to find the new, improved design. For the structural analysis phase, the equation solver for the system of simultaneous, linear equations plays a key role since it is needed for either static, or eigenvalue, or dynamic analysis. For practical, large-scale structural analysis-synthesis applications, computational time can be excessively large. Thus, it is necessary to have a new structural analysis-synthesis code which employs new solution algorithms to exploit both parallel and vector capabilities offered by modern, high performance computers such as the Convex, Cray-2 and Cray-YMP computers. The objective of this research project is, therefore, to incorporate the latest development in the parallel-vector equation solver, PVSOLVE into the widely popular finite-element production code, such as the SAP-4. Furthermore, several nonlinear unconstrained optimization subroutines have also been developed and tested under a parallel computer environment. The unconstrained optimization subroutines are not only useful in their own right, but they can also be incorporated into a more popular constrained optimization code, such as ADS.

  2. Gastropod diversification and community structuring processes in ancient Lake Ohrid: a metacommunity speciation perspective

    NASA Astrophysics Data System (ADS)

    Hauffe, T.; Albrecht, C.; Wilke, T.

    2015-09-01

    The Balkan Lake Ohrid is the oldest and most speciose freshwater lacustrine system in Europe. However, it remains unclear whether the diversification of its endemic taxa is mainly driven by neutral processes, environmental factors, or species interactions. This calls for a holistic perspective involving both evolutionary processes and ecological dynamics. Such a unifying framework - the metacommunity speciation model - considers how community assembly affects diversification and vice versa by assessing the relative contribution of the three main community assembly processes, dispersal limitation, environmental filtering, and species interaction. The current study therefore used the species-rich model taxon Gastropoda to assess how extant communities in Lake Ohrid are structured by performing process based metacommunity analyses. Specifically, the study aimed at (i) identifying the relative importance of the three community assembly processes and (ii) to test whether the importance of these individual processes changes gradually with lake depth or whether they are distinctively related to eco-zones. Based on specific simulation steps for each of the three processes, it could be demonstrated that dispersal limitation had the strongest influence on gastropod community structures in Lake Ohrid. However, it was not the exclusive assembly process but acted together with the other two processes - environmental filtering, and species interaction. In fact, the relative importance of the three community assembly processes varied both with lake depth and eco-zones, though the processes were better predicted by the latter. The study thus corroborated the high importance of dispersal limitation for both maintaining species richness in Lake Ohrid (through its impact on community structure) and generating endemic biodiversity (via its influence on diversification processes). However, according to the metacommunity speciation model, the inferred importance of environmental

  3. On a numerical solution of the plastic buckling problem of structures

    NASA Technical Reports Server (NTRS)

    Gupta, K. K.

    1978-01-01

    An automated digital computer procedure is presented for the accurate and efficient solution of the plastic buckling problem of structures. This is achieved by a Sturm sequence method employing a bisection strategy, which eliminates the need for having to solve the buckling eigenvalue problem at each incremental (decremental) loading stage that is associated with the usual solution techniques. The plastic buckling mode shape is determined by a simple inverse iteration process, once the buckling load has been established. Numerical results are presented for plate problems with various edge conditions. The resulting computer program written in FORTRAN V for the JPL UNIVAC 1108 machine proves to be most economical in comparison with other existing methods of such analysis.

  4. PRESENT STATE AND PROBLEMS OF ASSET MANAGEMENT IN THE UNDERGROUND STRUCTURE

    NASA Astrophysics Data System (ADS)

    Kamemura, Katsumi; Ikejiri, Takeshi; Kushido, Hitoshi; Sasao, Haruo; Takahashi, Akira; Yamada, Hiroyuki

    Improvement of infrastructures in Japan is now shifting its pivoting foot from the age of construction and increasing to the age of maintenance. After the importance of maintenance was pointed out, a lot of studies about engineering techniques concerning to the maintenance has been carried out at various organizations and authorities.However, their effort is not enough till now for the establishment of rational maintenance techniques, especially in the underground structures. On the other hand, against the background of the realization for safer and more secured society, the use of an underground space is more and more expected. So the development of the maintenance and management technique in the underground structure becomes more and more important, indispensable problem. Here, the technique to evaluate the performance and the deterioration characteristic of the underground structure were examined from the viewpoint of the asset management, aiming at contributing to the establishment of the maintenance and management technique of the underground structure.

  5. Key labeling technologies to tackle sizeable problems in RNA structural biology.

    PubMed

    Dayie, Kwaku T

    2008-06-01

    The ability to adopt complex three-dimensional (3D) structures that can rapidly interconvert between multiple functional states (folding and dynamics) is vital for the proper functioning of RNAs. Consequently, RNA structure and dynamics necessarily determine their biological function. In the post-genomic era, it is clear that RNAs comprise a larger proportion (>50%) of the transcribed genome compared to proteins (< or =2%). Yet the determination of the 3D structures of RNAs lags considerably behind those of proteins and to date there are even fewer investigations of dynamics in RNAs compared to proteins. Site specific incorporation of various structural and dynamic probes into nucleic acids would likely transform RNA structural biology. Therefore, various methods for introducing probes for structural, functional, and biotechnological applications are critically assessed here. These probes include stable isotopes such as (2)H, (13)C, (15)N, and (19)F. Incorporation of these probes using improved RNA ligation strategies promises to change the landscape of structural biology of supramacromolecules probed by biophysical tools such as nuclear magnetic resonance (NMR) spectroscopy, X-ray crystallography and Raman spectroscopy. Finally, some of the structural and dynamic problems that can be addressed using these technological advances are outlined.

  6. The significance of the evanescent spectrum in structure-waveguide interaction problems.

    PubMed

    Tsouvalas, Apostolos; van Dalen, Karel N; Metrikine, Andrei V

    2015-10-01

    Modal decomposition is often applied in elastodynamics and acoustics for the solution of problems related to propagation of mechanical disturbances in waveguides. One of the key elements of this method is the solution of an eigenvalue problem for obtaining the roots of the dispersion equation, which signify the wavenumbers of the waves that may exist in the system. For non-dissipative media, the wavenumber spectrum consists of a finite number of real roots supplemented by infinitely many imaginary and complex ones. The former refer to the propagating modes in the medium, whereas the latter constitute the so-called evanescent spectrum. This study investigates the significance of the evanescent spectrum in structure-waveguide interaction problems. Two cases are analysed, namely, a beam in contact with a fluid layer and a cylindrical shell interacting with an acousto-elastic waveguide. The first case allows the introduction of a modal decomposition method and the establishment of appropriate criteria for the truncation of the modal expansions in a simple mathematical framework. The second case describes structure-borne wave radiation in an offshore environment during the installation of a pile with an impact hammer-a problem that has raised serious concerns in recent years due to the associated underwater noise pollution. PMID:26520340

  7. Protein production from the structural genomics perspective: achievements and future needs

    PubMed Central

    Almo, Steven C; Garforth, Scott J; Hillerich, Brandan S; Love, James D; Seidel, Ronald D; Burley, Stephen K

    2014-01-01

    Despite a multitude of recent technical breakthroughs speeding high-resolution structural analysis of biological macromolecules, production of sufficient quantities of well-behaved, active protein continues to represent the rate-limiting step in many structure determination efforts. These challenges are only amplified when considered in the context of ongoing structural genomics efforts, which are now contending with multi-domain eukaryotic proteins, secreted proteins, and ever-larger macromolecular assemblies. Exciting new developments in eukaryotic expression platforms, including insect and mammalian-based systems, promise enhanced opportunities for structural approaches to some of the most important biological problems. Development and implementation of automated eukaryotic expression techniques promises to significantly improve production of materials for structural, functional, and biomedical research applications. PMID:23642905

  8. Hybrid state vector methods for structural dynamic and aeroelastic boundary value problems

    NASA Technical Reports Server (NTRS)

    Lehman, L. L.

    1982-01-01

    A computational technique is developed that is suitable for performing preliminary design aeroelastic and structural dynamic analyses of large aspect ratio lifting surfaces. The method proves to be quite general and can be adapted to solving various two point boundary value problems. The solution method, which is applicable to both fixed and rotating wing configurations, is based upon a formulation of the structural equilibrium equations in terms of a hybrid state vector containing generalized force and displacement variables. A mixed variational formulation is presented that conveniently yields a useful form for these state vector differential equations. Solutions to these equations are obtained by employing an integrating matrix method. The application of an integrating matrix provides a discretization of the differential equations that only requires solutions of standard linear matrix systems. It is demonstrated that matrix partitioning can be used to reduce the order of the required solutions. Results are presented for several example problems in structural dynamics and aeroelasticity to verify the technique and to demonstrate its use. These problems examine various types of loading and boundary conditions and include aeroelastic analyses of lifting surfaces constructed from anisotropic composite materials.

  9. Physician perspectives on the structure and function of group practice HMOs.

    PubMed

    Kralewski, J E; Feldman, R; Gifford, G

    1992-01-01

    This article explores physicians' perspectives regarding how their HMOs function and their satisfaction with and loyalty to HMOs. Three HMOs were studied: a mature (28-year-old) staff model, a 16-year-old staff model, and a 13-year-old group model with both HMO and fee-for-service patients. While these HMOs were found to vary somewhat in terms of emphasis on patient care versus costs, methods used to control costs and degrees of centralization of decision making, they all received high overall satisfaction and loyalty scores. The staff model HMO with a more decentralized decision making structure received the highest satisfaction/loyalty score from its physicians. The degree to which physicians perceive the HMO to be effective and supportive and the use of educational programs and peer review to influence resource use were also found to be significantly related to physician satisfaction and loyalty.

  10. The "Prisoners Are People" Perspective--And the Problems of Promoting Learning Where This Outlook Is Rejected.

    ERIC Educational Resources Information Center

    Warner, Kevin

    1998-01-01

    Explores the philosophy in the Council of Europe's European Prison Rules and a report advocating a transformative adult education orientation in corrections. Contrasts this perspective with current Anglo-American penal policy, in which negative stereotypes, vengeful attitudes, and massive increases in incarceration are inimical to genuine…

  11. Supporting Graduate Students of Color in Educational Administration Preparation Programs: Faculty Perspectives on Best Practices, Possibilities, and Problems

    ERIC Educational Resources Information Center

    Young, Michelle D.; Brooks, Jeffrey S.

    2008-01-01

    Overview: This article presents findings from a study that examined faculty perspectives on how individual faculty members and institutions support graduate students of color in educational administration preparation programs. Purpose: The purpose of this study was to identify strategies that faculty members and institutions employ to support…

  12. Who Is Your Champion? A Close Look at How Plant and Animal Structures Can Help Solve a Problem

    ERIC Educational Resources Information Center

    Walker, Caryn; Ethington, Roberta L.; Stark, Alyssa Y.

    2016-01-01

    Everyone has problems, from the smallest ant competing for a food source to the largest elephant needing to cool down. Fortunately, organisms have structures that function to help them solve these problems. So when a group of fourth-grade students look for solutions to their problems, who do they turn to? A biological champion, of course! Plants…

  13. Identifying the number of population clusters with structure: problems and solutions.

    PubMed

    Gilbert, Kimberly J

    2016-05-01

    The program structure has been used extensively to understand and visualize population genetic structure. It is one of the most commonly used clustering algorithms, cited over 11,500 times in Web of Science since its introduction in 2000. The method estimates ancestry proportions to assign individuals to clusters, and post hoc analyses of results may indicate the most likely number of clusters, or populations, on the landscape. However, as has been shown in this issue of Molecular Ecology Resources by Puechmaille (), when sampling is uneven across populations or across hierarchical levels of population structure, these post hoc analyses can be inaccurate and identify an incorrect number of population clusters. To solve this problem, Puechmaille () presents strategies for subsampling and new analysis methods that are robust to uneven sampling to improve inferences of the number of population clusters. PMID:27062588

  14. Analysis of random structure-acoustic interaction problems using coupled boundary element and finite element methods

    NASA Technical Reports Server (NTRS)

    Mei, Chuh; Pates, Carl S., III

    1994-01-01

    A coupled boundary element (BEM)-finite element (FEM) approach is presented to accurately model structure-acoustic interaction systems. The boundary element method is first applied to interior, two and three-dimensional acoustic domains with complex geometry configurations. Boundary element results are very accurate when compared with limited exact solutions. Structure-interaction problems are then analyzed with the coupled FEM-BEM method, where the finite element method models the structure and the boundary element method models the interior acoustic domain. The coupled analysis is compared with exact and experimental results for a simplistic model. Composite panels are analyzed and compared with isotropic results. The coupled method is then extended for random excitation. Random excitation results are compared with uncoupled results for isotropic and composite panels.

  15. Identifying the number of population clusters with structure: problems and solutions.

    PubMed

    Gilbert, Kimberly J

    2016-05-01

    The program structure has been used extensively to understand and visualize population genetic structure. It is one of the most commonly used clustering algorithms, cited over 11,500 times in Web of Science since its introduction in 2000. The method estimates ancestry proportions to assign individuals to clusters, and post hoc analyses of results may indicate the most likely number of clusters, or populations, on the landscape. However, as has been shown in this issue of Molecular Ecology Resources by Puechmaille (), when sampling is uneven across populations or across hierarchical levels of population structure, these post hoc analyses can be inaccurate and identify an incorrect number of population clusters. To solve this problem, Puechmaille () presents strategies for subsampling and new analysis methods that are robust to uneven sampling to improve inferences of the number of population clusters.

  16. Associations between family structure change and child behavior problems: the moderating effect of family income.

    PubMed

    Ryan, Rebecca M; Claessens, Amy; Markowitz, Anna J

    2015-01-01

    This study investigated conditions under which family structure matters most for child well-being. Using data from the Children of the National Longitudinal Survey of Youth (n = 3,936), a national sample of U.S. families, it was estimated how changes in family structure related to changes in children's behavior between age 3 and 12 separately by household income level to determine whether associations depended on families' resources. Early changes in family structure, particularly from a two-biological-parent to single-parent family, predicted increases in behavior problems more than later changes, and movements into single and stepparent families mattered more for children of higher versus lower income parents. Results suggest that for children of higher income parents, moving into a stepfamily may improve, not undermine, behavior.

  17. Current Crisis in Science Education? Women in Science and Problems for the Behavioral Scientists. Some Perspectives of a Physicist.

    ERIC Educational Resources Information Center

    Dresselhaus, Mildred S.

    A number of problems exist in society which require the cooperation of physical and social scientists. One of these problems is the current crisis in science education. There are several aspects to this problem, including the declining interest of students in math and science at a time when functioning in our society requires more, not less,…

  18. You Need to Know: There Is a Causal Relationship between Structural Knowledge and Control Performance in Complex Problem Solving Tasks

    ERIC Educational Resources Information Center

    Goode, Natassia; Beckmann, Jens F.

    2010-01-01

    This study investigates the relationships between structural knowledge, control performance and fluid intelligence in a complex problem solving (CPS) task. 75 participants received either complete, partial or no information regarding the underlying structure of a complex problem solving task, and controlled the task to reach specific goals.…

  19. Coulombic Interaction in Finnish Middle School Chemistry: A Systemic Perspective on Students' Conceptual Structure of Chemical Bonding

    ERIC Educational Resources Information Center

    Joki, Jarkko; Lavonen, Jari; Juuti, Kalle; Aksela, Maija

    2015-01-01

    The aim of this study was to design a novel and holistic way to teach chemical bonding at the middle school level according to research on the teaching and learning of bonding. A further aim was to investigate high achieving middle school students' conceptual structures concerning chemical bonding by using a systemic perspective. Students in one…

  20. Experiences and Perspectives of Diverse Adolescent Youth Who Are Gifted: Navigating the Social and Organizational Structures of Public Schooling

    ERIC Educational Resources Information Center

    Baker, Jamie S.

    2012-01-01

    This qualitative case study explores the experiences and perspectives of seven diverse adolescent youth who are gifted as they navigate the social and organizational structures of public schooling as participants in gifted programming. Recent trends in education and the historical exploitations of giftedness that service the few, rather than the…

  1. Structural and Psychological Empowerment Climates, Performance, and the Moderating Role of Shared Felt Accountability: A Managerial Perspective

    ERIC Educational Resources Information Center

    Wallace, J. Craig; Johnson, Paul D.; Mathe, Kimberly; Paul, Jeff

    2011-01-01

    The authors proposed and tested a model in which data were collected from managers (n = 539) at 116 corporate-owned quick service restaurants to assess the structural and psychological empowerment process as moderated by shared-felt accountability on indices of performance from a managerial perspective. The authors found that empowering leadership…

  2. Activity Structures and the Unfolding of Problem-Solving Actions in High-School Chemistry Classrooms

    NASA Astrophysics Data System (ADS)

    Criswell, Brett A.; Rushton, Greg T.

    2014-02-01

    In this paper, we argue for a more systematic approach for studying the relationship between classroom practices and scientific practices—an approach that will likely better support the systemic reforms being promoted in the Next Generation Science Standards in the USA and similar efforts in other countries. One component of that approach is looking at how the nature of the activity structure may influence the relative alignment between classroom and scientific practices. To that end, we build on previously published research related to the practices utilized by five high-school chemistry teachers as they enacted problem-solving activities in which students were likely to generate proposals that were not aligned with normative scientific understandings. In that prior work, our analysis had emphasized micro-level features of the talk interactions and how they related to the way students' ideas were explored; in the current paper, the analysis zooms out to consider the macro-level nature of the enactments associated with the activity structure of each lesson examined. Our data show that there were two general patterns to the activity structure across the 14 lessons scrutinized, and that each pattern had associated with it a constellation of features that impinged on the way the problem space was navigated. A key finding is that both activity structures (the expansive and the open) had features that aligned with scientific practices espoused in the Next Generation Science Standards—and both had features that were not aligned with those practices. We discuss the nature of these two structures, evidence of the relationship of each structure to key features of how the lessons unfolded, and the implications of these findings for both future research and the training of teachers.

  3. Semi-analytic approach for electromagnetic problems of large arrays structures

    NASA Astrophysics Data System (ADS)

    Rostami-Angas, Masoud

    helps us in finding the microscopic charactristics of the structure. Building on the theory that the molecules can be modeled by electric dipoles; a semi-analytic and semi-classical approach is developed to solve the electromagnetic problem of large array of dipoles and simulate the optical response of molecular aggregates. In chapter 3, a double negative (DNG) metamaterial structure is designed by unit cells of multilayer (concentric) spheres. The dispersion diagram is analyzed to find the frequency band with negative group velocity and the losses in DNG region. Basically, the combination of a positive permittivity dielectric and a negative permittivity plasmonic material can control the resonances of unit cells and therefore the effective permittivity of the 3-D structure. It is also discussed how a novel design of multilayer sphere unit cells leads to the DNG performance at the desired frequency band. In chapter 4, analytical solution to the problem of electromagnetic wave scattering by an arbitrary array of non-concentric spheres is derived. A full wave multipole expansion method is applied to express the electromagnetic fields in terms of the electric and magnetic dipole modes and the higher order moments. Vector spherical wave functions are used as the basis functions of the multipole expansions and the translation addition theorem is implemented to expand fields in desired coordinate systems. The accuracy and computational performance of the model are investigated and some interesting applications are discussed.

  4. Explicit and implicit soil modelling for dynamic soil-structure interaction problems

    NASA Astrophysics Data System (ADS)

    Dasgupta, Aaron

    1986-10-01

    Increased application of nonlinear viscoelastic materials in structures and consideration of operating environments require modeling of interaction of such structures with the surrounding soil medium which significantly influences the dynamic response when subjected to an impulse or blast overpressure loading. The need is accentuated by the rapid advances in numerical modeling of dynamic problems using either finite difference or finite element techniques of structural analysis. An explicit modeling technique is recommended whereby a few layers of soil surrounding the base of the structure are modeled as an assembly of elements in contact with the structure. The interfacing contact elements for both structure and soil are allowed to stick, slide or separate from each other to simulate the appropriate boundary conditions. The explicit modeling technique using a finite element code requires characterization of constitutive relationship of geological materials from shock compression behavior of such materials and their Hugoniot characteristics. The characterization technique used here is currently restricted to materials with linear Hugoniot characteristics at all pressure ranges.

  5. Possibilities of the particle finite element method for fluid-soil-structure interaction problems

    NASA Astrophysics Data System (ADS)

    Oñate, Eugenio; Celigueta, Miguel Angel; Idelsohn, Sergio R.; Salazar, Fernando; Suárez, Benjamín

    2011-09-01

    We present some developments in the particle finite element method (PFEM) for analysis of complex coupled problems in mechanics involving fluid-soil-structure interaction (FSSI). The PFEM uses an updated Lagrangian description to model the motion of nodes (particles) in both the fluid and the solid domains (the later including soil/rock and structures). A mesh connects the particles (nodes) defining the discretized domain where the governing equations for each of the constituent materials are solved as in the standard FEM. The stabilization for dealing with an incompressibility continuum is introduced via the finite calculus method. An incremental iterative scheme for the solution of the non linear transient coupled FSSI problem is described. The procedure to model frictional contact conditions and material erosion at fluid-solid and solid-solid interfaces is described. We present several examples of application of the PFEM to solve FSSI problems such as the motion of rocks by water streams, the erosion of a river bed adjacent to a bridge foundation, the stability of breakwaters and constructions sea waves and the study of landslides.

  6. Traveling salesman problems with PageRank Distance on complex networks reveal community structure

    NASA Astrophysics Data System (ADS)

    Jiang, Zhongzhou; Liu, Jing; Wang, Shuai

    2016-12-01

    In this paper, we propose a new algorithm for community detection problems (CDPs) based on traveling salesman problems (TSPs), labeled as TSP-CDA. Since TSPs need to find a tour with minimum cost, cities close to each other are usually clustered in the tour. This inspired us to model CDPs as TSPs by taking each vertex as a city. Then, in the final tour, the vertices in the same community tend to cluster together, and the community structure can be obtained by cutting the tour into a couple of paths. There are two challenges. The first is to define a suitable distance between each pair of vertices which can reflect the probability that they belong to the same community. The second is to design a suitable strategy to cut the final tour into paths which can form communities. In TSP-CDA, we deal with these two challenges by defining a PageRank Distance and an automatic threshold-based cutting strategy. The PageRank Distance is designed with the intrinsic properties of CDPs in mind, and can be calculated efficiently. In the experiments, benchmark networks with 1000-10,000 nodes and varying structures are used to test the performance of TSP-CDA. A comparison is also made between TSP-CDA and two well-established community detection algorithms. The results show that TSP-CDA can find accurate community structure efficiently and outperforms the two existing algorithms.

  7. A Philosophical Perspective on the Relation between Cortical Midline Structures and the Self

    PubMed Central

    Musholt, Kristina

    2013-01-01

    In recent years there has been increasing evidence that an area in the brain called the cortical midline structures (CMSs) is implicated in what has been termed self-related processing. This article will discuss recent evidence for the relation between CMS and self-consciousness in light of several important philosophical distinctions. First, we should distinguish between being a self (i.e., being a subject of conscious experience) and being aware of being a self (i.e., being able to think about oneself as such). While the former consists in having a first-person perspective on the world, the latter requires the ability to explicitly represent one’s own perspective as such. Further, we should distinguish between being aware of oneself “as subject” and being aware of oneself “as object.” The focus of existing studies investigating the relation between CMS and self has been predominantly on the ability to think about oneself (and in particular thinking of oneself “as object”), while the more basic aspects involved in being a self have been neglected. However, it is important to widen the scope of the cognitive neuroscience to include the latter, not least because this might have important implications for a better understanding of disorders of the self, such as those involved in schizophrenia. In order to do so, cognitive neuroscience should work together with philosophy, including phenomenology. Second, we need to distinguish between personal and subpersonal level explanations. It will be argued that although it is important to respect this distinction, in principle, some subpersonal facts can enter into constitutive conditions of personal-level phenomena. However, in order for this to be possible, one needs both careful conceptual analysis and knowledge about relevant cognitive mechanisms. PMID:24032013

  8. Scaffolding Middle School Students' Content Knowledge and Ill-Structured Problem Solving in a Problem-Based Hypermedia Learning Environment

    ERIC Educational Resources Information Center

    Bulu, Saniye Tugba; Pedersen, Susan

    2010-01-01

    This study investigated the effects of domain-general and domain-specific scaffolds with different levels of support, continuous and faded, on learning of scientific content and problem-solving. Students' scores on a multiple-choice pretest, posttest, and four recommendation forms were analyzed. Students' content knowledge in all conditions…

  9. First-passage problems: A probabilistic dynamic analysis for degraded structures

    NASA Technical Reports Server (NTRS)

    Shiao, Michael C.; Chamis, Christos C.

    1990-01-01

    Structures subjected to random excitations with uncertain system parameters degraded by surrounding environments (a random time history) are studied. Methods are developed to determine the statistics of dynamic responses, such as the time-varying mean, the standard deviation, the autocorrelation functions, and the joint probability density function of any response and its derivative. Moreover, the first-passage problems with deterministic and stationary/evolutionary random barriers are evaluated. The time-varying (joint) mean crossing rate and the probability density function of the first-passage time for various random barriers are derived.

  10. Fractal structures for the Jacobi Hamiltonian of restricted three-body problem

    NASA Astrophysics Data System (ADS)

    Rollin, G.; Lages, J.; Shepelyansky, D. L.

    2016-08-01

    We study the dynamical chaos and integrable motion in the planar circular restricted three-body problem and determine the fractal dimension of the spiral strange repeller set of non-escaping orbits at different values of mass ratio of binary bodies and of Jacobi integral of motion. We find that the spiral fractal structure of the Poincaré section leads to a spiral density distribution of particles remaining in the system. We also show that the initial exponential drop of survival probability with time is followed by the algebraic decay related to the universal algebraic statistics of Poincaré recurrences in generic symplectic maps.

  11. Analysis of factors affecting satisfaction level on problem based learning approach using structural equation modeling

    NASA Astrophysics Data System (ADS)

    Hussain, Nur Farahin Mee; Zahid, Zalina

    2014-12-01

    Nowadays, in the job market demand, graduates are expected not only to have higher performance in academic but they must also be excellent in soft skill. Problem-Based Learning (PBL) has a number of distinct advantages as a learning method as it can deliver graduates that will be highly prized by industry. This study attempts to determine the satisfaction level of engineering students on the PBL Approach and to evaluate their determinant factors. The Structural Equation Modeling (SEM) was used to investigate how the factors of Good Teaching Scale, Clear Goals, Student Assessment and Levels of Workload affected the student satisfaction towards PBL approach.

  12. Teaching ill-structured problem solving using occupational therapy practice epistemology.

    PubMed

    Mitchell, Anita Witt

    2013-01-01

    ABSTRACT Epistemic and ontological cognition (EOC) have to do with an individual's beliefs about knowledge and knowing. Research has shown that EOC have an influence on learning and achievement. EOC may be discipline-specific with a profession being defined by its practice epistemology. If an individual's EOC is inconsistent with the profession's practice epistemology, the student or practitioner may struggle with effectively solving ill-structured occupational performance problems. The purpose of this paper is to increase awareness of the constructs of EOC, to describe its importance to occupational therapy education and practice, and to provide recommendations for educators and researchers. Specific examples are detailed and recommendations for future research are proposed.

  13. Algorithmic Perspectives of Network Transitive Reduction Problems and their Applications to Synthesis and Analysis of Biological Networks

    PubMed Central

    Aditya, Satabdi; DasGupta, Bhaskar; Karpinski, Marek

    2013-01-01

    In this survey paper, we will present a number of core algorithmic questions concerning several transitive reduction problems on network that have applications in network synthesis and analysis involving cellular processes. Our starting point will be the so-called minimum equivalent digraph problem, a classic computational problem in combinatorial algorithms. We will subsequently consider a few non-trivial extensions or generalizations of this problem motivated by applications in systems biology. We will then discuss the applications of these algorithmic methodologies in the context of three major biological research questions: synthesizing and simplifying signal transduction networks, analyzing disease networks, and measuring redundancy of biological networks. PMID:24833332

  14. Key technological issues in LMFBR high-temperature structural design - the US perspective

    SciTech Connect

    Corum, J.M.

    1984-01-01

    The purpose of this paper is: (1) to review the key technological issues in LMFBR high-temperature structural design, particularly as they relate to cost reduction; and (2) to provide an overview of activities sponsored by the US Department of Energy to resolve the issues and to establish stable, standardized, and defensible structural design methods and criteria. Specific areas of discussion include: weldments, structural validation tests, simplified design analysis procedures, design procedures for piping, validation of the methodology for notch-like geometries, improved life assessment procedures, thermal striping, extension of the methodology to new materials, and ASME high-temperature Code reform needs. The perceived problems and needs in each area are discussed, and the current status of related US activities is given.

  15. An explicit solution to the optimal LQG problem for flexible structures with collocated rate sensors

    NASA Technical Reports Server (NTRS)

    Balakrishnan, A. V.

    1993-01-01

    We present a class of compensators in explicit form (not requiring numerical computer calculations) for stabilizing flexible structures with collocated rate sensors. They are based on the explicit solution, valid for both Continuum and FEM Models, of the LQG problem for minimizing mean square rate. They are robust with respect to system stability (will not destabilize modes even with mismatch of parameters), can be instrumented in state space form suitable for digital controllers, and can be specified directly from the structure modes and mode 'signature' (displacement vectors at sensor locations). Some simulation results are presented for the NASA LaRC Phase-Zero Evolutionary Model - a modal Trust model with 86 modes - showing damping ratios attainable as a function of compensator design parameters and complexity.

  16. Self-assembly and structural-functional flexibility of oxygenic photosynthetic machineries: personal perspectives.

    PubMed

    Garab, Győző

    2016-01-01

    This short review, with a bit of historical aspect and a strong personal bias and emphases on open questions, is focusing on the (macro-)organization and structural-functional flexibilities of the photosynthetic apparatus of oxygenic photosynthetic organisms at different levels of the structural complexity-selected problems that have attracted most my attention in the past years and decades. These include (i) the anisotropic organization of the pigment-protein complexes and photosynthetic membranes-a basic organizing principle of living matter, which can, and probably should be adopted to intelligent materials; (ii) the organization of protein complexes into chiral macrodomains, large self-assembling highly organized but structurally flexible entities with unique spectroscopic fingerprints-structures, where, important, high-level regulatory functions appear to 'reside'; (iii) a novel, dissipation-assisted mechanism of structural changes, based on a thermo-optic effect: ultrafast thermal transients in the close vicinity of dissipation of unused excitation energy, which is capable of inducing elementary structural changes; it makes plants capable of responding to excess excitation with reaction rates proportional to the overexcitation above the light-saturation of photosynthesis; (iv) the 3D ultrastructure of the granum-stroma thylakoid membrane assembly and other multilamellar membrane systems, and their remodelings-associated with regulatory mechanisms; (v) the molecular organization and structural-functional plasticity of the main light-harvesting complex of plants, in relation to their crystal structure and different in vivo and in vitro states; and (vi) the enigmatic role of non-bilayer lipids and lipid phases in the bilayer thylakoid membrane-warranting its high protein content and contributing to its structural flexibility. PMID:26494196

  17. Socio-Demographic and Practice-Oriented Factors Related to Proficiency in Problem Solving: A Lifelong Learning Perspective

    ERIC Educational Resources Information Center

    Desjardins, Richard; Ederer, Peer

    2015-01-01

    This article explores the relative importance of different socio-demographic and practice-oriented factors that are related to proficiency in problem solving in technology-rich environments (PSTREs) and by extension may be related to complex problem solving (CPS). The empirical analysis focuses on the proficiency measurements of PSTRE made…

  18. The Perspectives of Individuals with Cognitive Disabilities and/or Autism on Their Lives and Their Problem Behavior.

    ERIC Educational Resources Information Center

    Ruef, Michael B.; Turnbull, Ann P.

    2002-01-01

    This study explored perceptions of nine adults with cognitive disabilities and/or autism regarding barriers and solutions experienced due to problem behavior and elicited suggestions for improving quality of life while reducing problem behavior. Emergent themes included communication difficulties, need for privacy and personal decision making, and…

  19. Enhancing Grade 10 Thai Students' Stoichiometry Understanding and Ability to Solve Numerical Problems via a Conceptual Change Perspective

    ERIC Educational Resources Information Center

    Dahsah, Chanyah; Coll, Richard K.; Sung-ong, Sunan; Yutakom, Naruemon; Sanguanruang, Sudjit

    2008-01-01

    The international literature suggests students frequently resort to the use of formulae when solving stoichiometry problems without understanding the concepts. In prior work we identified Thai student alternative conceptions and ability to solve numerical problem for stoichiometry. The results indicate that many Thai students also hold alternative…

  20. A memory structure adapted simulated annealing algorithm for a green vehicle routing problem.

    PubMed

    Küçükoğlu, İlker; Ene, Seval; Aksoy, Aslı; Öztürk, Nursel

    2015-03-01

    Currently, reduction of carbon dioxide (CO2) emissions and fuel consumption has become a critical environmental problem and has attracted the attention of both academia and the industrial sector. Government regulations and customer demands are making environmental responsibility an increasingly important factor in overall supply chain operations. Within these operations, transportation has the most hazardous effects on the environment, i.e., CO2 emissions, fuel consumption, noise and toxic effects on the ecosystem. This study aims to construct vehicle routes with time windows that minimize the total fuel consumption and CO2 emissions. The green vehicle routing problem with time windows (G-VRPTW) is formulated using a mixed integer linear programming model. A memory structure adapted simulated annealing (MSA-SA) meta-heuristic algorithm is constructed due to the high complexity of the proposed problem and long solution times for practical applications. The proposed models are integrated with a fuel consumption and CO2 emissions calculation algorithm that considers the vehicle technical specifications, vehicle load, and transportation distance in a green supply chain environment. The proposed models are validated using well-known instances with different numbers of customers. The computational results indicate that the MSA-SA heuristic is capable of obtaining good G-VRPTW solutions within a reasonable amount of time by providing reductions in fuel consumption and CO2 emissions. PMID:25056743

  1. A practical solution in delineating thin conducting structures and suppression problem in direct current resistivity sounding

    NASA Astrophysics Data System (ADS)

    Sharma, Shashi Prakash; Biswas, Arkoprovo

    2013-08-01

    In hard rock areas, conventional apparent resistivity measurement using Schlumberger resistivity sounding fails to detect thin conducting structures (2-D and 3-D fractures filled with groundwater and mineral aggregate) concealed at a large depth. In the present study, an attempt is made to way-out the detection problem of deep seated thin conducting layer. It is proposed to study the apparent conductance simultaneously with resistivity sounding to detect such conductive zones qualitatively. Apparent conductance is defined as the magnitude of current flowing in the subsurface for a unit applied voltage through current electrodes. Even though such measurement is of qualitative importance, it gives extremely valuable information for the presence of conductive zones at depth in challenging hard rock terrain. It has been observed that apparent conductance increases significantly when groundwater bearing fractures and conductive bodies are encountered in the subsurface. Field data from different locations are presented to demonstrate the efficacy of such measurement. The measurement assists to the conventional resistivity sounding for successful prediction of groundwater zones at large depth in different hard rock areas and is of enormous importance. The approach is also used for possible solution of suppression problem in the DC resistivity sounding when intermediate layer is not reflected in the resistivity sounding curve. Finally, the approach can be used together with resistivity sounding to solve many practical problems.

  2. Structuring policy problems for plastics, the environment and human health: reflections from the UK

    PubMed Central

    Shaxson, Louise

    2009-01-01

    How can we strengthen the science–policy interface for plastics, the environment and human health? In a complex policy area with multiple stakeholders, it is important to clarify the nature of the particular plastics-related issue before trying to understand how to reconcile the supply and demand for evidence in policy. This article proposes a simple problem typology to assess the fundamental characteristics of a policy issue and thus identify appropriate processes for science–policy interactions. This is illustrated with two case studies from one UK Government Department, showing how policy and science meet over the environmental problems of plastics waste in the marine environment and on land. A problem-structuring methodology helps us understand why some policy issues can be addressed through relatively linear flows of science from experts to policymakers but why others demand a more reflexive approach to brokering the knowledge between science and policy. Suggestions are given at the end of the article for practical actions that can be taken on both sides. PMID:19528061

  3. A memory structure adapted simulated annealing algorithm for a green vehicle routing problem.

    PubMed

    Küçükoğlu, İlker; Ene, Seval; Aksoy, Aslı; Öztürk, Nursel

    2015-03-01

    Currently, reduction of carbon dioxide (CO2) emissions and fuel consumption has become a critical environmental problem and has attracted the attention of both academia and the industrial sector. Government regulations and customer demands are making environmental responsibility an increasingly important factor in overall supply chain operations. Within these operations, transportation has the most hazardous effects on the environment, i.e., CO2 emissions, fuel consumption, noise and toxic effects on the ecosystem. This study aims to construct vehicle routes with time windows that minimize the total fuel consumption and CO2 emissions. The green vehicle routing problem with time windows (G-VRPTW) is formulated using a mixed integer linear programming model. A memory structure adapted simulated annealing (MSA-SA) meta-heuristic algorithm is constructed due to the high complexity of the proposed problem and long solution times for practical applications. The proposed models are integrated with a fuel consumption and CO2 emissions calculation algorithm that considers the vehicle technical specifications, vehicle load, and transportation distance in a green supply chain environment. The proposed models are validated using well-known instances with different numbers of customers. The computational results indicate that the MSA-SA heuristic is capable of obtaining good G-VRPTW solutions within a reasonable amount of time by providing reductions in fuel consumption and CO2 emissions.

  4. Differential evolution: Global search problem in LEED-IV surface structural analysis

    SciTech Connect

    Nascimento, V.B.; Plummer, E.W.

    2015-02-15

    The search process associated with the quantitative theory–experiment comparison in Low Energy Electron Diffraction surface structural analysis can be very time consuming, especially in the case of complex materials with many atoms in the unit cell. Global search algorithms need to be employed to locate the global minimum of the reliability factor in the multi-dimensional structural parameter space. In this study we investigate the use of the Differential Evolution algorithm in Low Energy Electron Diffraction structural analysis. Despite the simplicity of its mechanism the Differential Evolution algorithm presents an impressive performance when applied to ultra-thin films of BaTiO{sub 3}(001) in a theory–theory comparison. A scaling relation of N{sup (1.47} {sup ±} {sup 0.08)} was obtained, where N is the total number of parameters to be optimized. - Highlights: • We investigated the use of the Differential Evolution algorithm (DE) for the LEED search problem. • The DE method was applied to the optimization of the surface structure of the BaTiO{sub 3}(001) ultra-thin films. • A very favorable scaling relation of N{sup 1.47} was obtained, where N is the total number of parameters to be optimized.

  5. Climate-Change Problem Solving: Structured Approaches Based on Real-World Experiences

    NASA Astrophysics Data System (ADS)

    Rood, R. B.; Briley, L. J.; Brown, D. A.

    2012-12-01

    Nearly two decades of experience using both seasonal and long-term climate model projections has led to the identification of a set of characteristics of the successful use of climate knowledge in planning and adaptation applications. These characteristics include end-to-end knowledge systems, co-generation or co-production of solution approaches by scientists and practitioners, and tailoring climate model information to the decision-making processes of the specific application. Glisaclimate.org strives to apply the growing body of research into the successful use of climate knowledge using a set of prototype, real-world applications. We describe an online problem-solving environment whose design is based on the characteristics of the successful use of climate predictions and projections by practitioners such as resource managers, urban planners, public health professionals, and policy makers. Design features of Glisaclimate.org include: Based on principles extracted from social science studies of the use of climate information. Anchored on structured templates of problem solving with the identification of common steps in problem solving that are repeated in one application to the next. Informed by interviews with real-world users who desire to incorporate climate-science knowledge into their decision making. Built with open-source tools to allow participation of a community of developers and to facilitate the sustainability of the effort. A structured approach to problem solving is described by four functions of information management. At the foundation of problem solving is the collection of existing information, an inventory stage. Following the collection of the information there are analysis and evaluation stages. In the analysis stage interfaces are described and knowledge gaps are identified. The evaluation stage assesses the quality of the information and the relevance of the information to the specific attributes of the problem. The development of plans

  6. The intentional stance as structure learning: a computational perspective on mindreading.

    PubMed

    Dindo, Haris; Donnarumma, Francesco; Chersi, Fabian; Pezzulo, Giovanni

    2015-10-01

    Recent theories of mindreading explain the recognition of action, intention, and belief of other agents in terms of generative architectures that model the causal relations between observables (e.g., observed movements) and their hidden causes (e.g., action goals and beliefs). Two kinds of probabilistic generative schemes have been proposed in cognitive science and robotics that link to a "theory theory" and "simulation theory" of mindreading, respectively. The former compares perceived actions to optimal plans derived from rationality principles and conceptual theories of others' minds. The latter reuses one's own internal (inverse and forward) models for action execution to perform a look-ahead mental simulation of perceived actions. Both theories, however, leave one question unanswered: how are the generative models - including task structure and parameters - learned in the first place? We start from Dennett's "intentional stance" proposal and characterize it within generative theories of action and intention recognition. We propose that humans use an intentional stance as a learning bias that sidesteps the (hard) structure learning problem and bootstraps the acquisition of generative models for others' actions. The intentional stance corresponds to a candidate structure in the generative scheme, which encodes a simplified belief-desire folk psychology and a hierarchical intention-to-action organization of behavior. This simple structure can be used as a proxy for the "true" generative structure of others' actions and intentions and is continuously grown and refined - via state and parameter learning - during interactions. In turn - as our computational simulations show - this can help solve mindreading problems and bootstrap the acquisition of useful causal models of both one's own and others' goal-directed actions.

  7. Detection and characterization of usability problems in structured data entry interfaces in dentistry

    PubMed Central

    Walji, Muhammad F; Kalenderian, Elsbeth; Tran, Duong; Kookal, Krishna K; Nguyen, Vickie; Tokede, Oluwabunmi; White, Joel M; Vaderhobli, Ram; Ramoni, Rachel; Stark, Paul C; Kimmes, Nicole S.; Schoonheim-Klein, Meta E.; Patel, Vimla L

    2012-01-01

    Background Poor usability is one of the major barriers for optimally using electronic health records (EHRs). Dentists are increasingly adopting EHRs, and are using structured data entry interfaces to enter data such that the data can be easily retrieved and exchanged. Until recently, dentists have lacked a standardized terminology to consistently represent oral health diagnoses. Objectives In this study we evaluated the usability of a widely used EHR interface that allow the entry of diagnostic terms, using multi-faceted methods to identify problems and work with the vendor to correct them using an iterative design method. Methods Fieldwork was undertaken at two clinical sites, and dental students as subjects participated in user testing (n=32), interviews (n=36) and observations (n=24). Results User testing revealed that only 22–41% of users were able to successfully complete a simple task of entering one diagnosis, while no user was able to complete a more complex task. We identified and characterized 24 high-level usability problems reducing efficiency and causing user errors. Interface-related problems included unexpected approaches for displaying diagnosis, lack of visibility, and inconsistent use of UI widgets. Terminology related issues included missing and mis-categorized concepts. Work domain issues involved both absent and superfluous functions. In collaboration with the vendor, each usability problem was prioritized and a timeline set to resolve the concerns. Discussion Mixed methods evaluations identified a number of critical usability issues relating to the user interface, underlying terminology of the work domain. The usability challenges were found to prevent most users from successfully completing the tasks. Our further work we will determine if changes to the interface, terminology and work domain do result in improved usability. PMID:22749840

  8. Preferential flow in connected soil structures and the principle of "maximum energy dissipation": A thermodynamic perspective

    NASA Astrophysics Data System (ADS)

    Zehe, E.; Blume, T.; Bloeschl, G.

    2009-04-01

    "There is preferential flow at all scales"? This was a key message in a talk on ?Idle thoughts on a unifying theory of catchment hydrology? given by Bloeschl (2006). In this context ?preferential flow? was used to address rapid water flow along spatially connected flow paths of minimum flow resistance. Preferential flow seems in fact rather the rule than the exception. It occurs locally in non capillary macropores, at the hillslope scale in surface rills or through subsurface pipes. Rapid flow in connected biopores or sometimes shrinkage cracks is today accepted to play a key role for transport of agrochemicals in cohesive soils. The spatial distribution of worm burrows in the landscape may, furthermore, exert crucial control on rainfall runoff response and sediment yields at the hillslope and catchment scales. However, even if the population of connected biopores/macropores is known in soil we struggle in predicting onset, timing and strength of preferential flow events. Preferential flow is an intermittent, threshold phenomenon. Onset and intensity seems to be determined by the strength of the rainfall forcing and the wetness state of the soil. Furthermore, burrows of deep digging aenecic earthworms can ? even when being abandoned ? persist over decades as suggested by accumulation of clay particles or even radio nuclides. Thus, these structures ?survive? severe rainfall and subsurface flow events and still remain functional in the hydrological system. Why is it sometimes ?favourable? to take flow paths of minimum flow resistance and sometimes not? Why do these flow paths/ structures persist such a long time? Following Kleidon and Schimansky (2008) we suggest that a thermodynamic perspective ? looking at soil water flow as dissipative process in an open, non equilibrium thermodynamic system ? may help unrevealing these questions. However, we suggest a complementary perspective on soil water flow focusing rather on entropy production but on dissipation of

  9. The four ingredients of single-sequence RNA secondary structure prediction. A unifying perspective

    PubMed Central

    Rivas, Elena

    2013-01-01

    Any method for RNA secondary structure prediction is determined by four ingredients. The architecture is the choice of features implemented by the model (such as stacked basepairs, loop length distributions, etc.). The architecture determines the number of parameters in the model. The scoring scheme is the nature of those parameters (whether thermodynamic, probabilistic, or weights). The parameterization stands for the specific values assigned to the parameters. These three ingredients are referred to as “the model.” The fourth ingredient is the folding algorithms used to predict plausible secondary structures given the model and the sequence of a structural RNA. Here, I make several unifying observations drawn from looking at more than 40 years of methods for RNA secondary structure prediction in the light of this classification. As a final observation, there seems to be a performance ceiling that affects all methods with complex architectures, a ceiling that impacts all scoring schemes with remarkable similarity. This suggests that modeling RNA secondary structure by using intrinsic sequence-based plausible “foldability” will require the incorporation of other forms of information in order to constrain the folding space and to improve prediction accuracy. This could give an advantage to probabilistic scoring systems since a probabilistic framework is a natural platform to incorporate different sources of information into one single inference problem. PMID:23695796

  10. The four ingredients of single-sequence RNA secondary structure prediction. A unifying perspective.

    PubMed

    Rivas, Elena

    2013-07-01

    Any method for RNA secondary structure prediction is determined by four ingredients. The architecture is the choice of features implemented by the model (such as stacked basepairs, loop length distributions, etc.). The architecture determines the number of parameters in the model. The scoring scheme is the nature of those parameters (whether thermodynamic, probabilistic, or weights). The parameterization stands for the specific values assigned to the parameters. These three ingredients are referred to as "the model." The fourth ingredient is the folding algorithms used to predict plausible secondary structures given the model and the sequence of a structural RNA. Here, I make several unifying observations drawn from looking at more than 40 years of methods for RNA secondary structure prediction in the light of this classification. As a final observation, there seems to be a performance ceiling that affects all methods with complex architectures, a ceiling that impacts all scoring schemes with remarkable similarity. This suggests that modeling RNA secondary structure by using intrinsic sequence-based plausible "foldability" will require the incorporation of other forms of information in order to constrain the folding space and to improve prediction accuracy. This could give an advantage to probabilistic scoring systems since a probabilistic framework is a natural platform to incorporate different sources of information into one single inference problem.

  11. Associations between Psychological Problems and Quality of Life in Pediatric Short Stature from Patients' and Parents' Perspectives.

    PubMed

    Quitmann, Julia Hannah; Bullinger, Monika; Sommer, Rachel; Rohenkohl, Anja Christine; Bernardino Da Silva, Neuza Maria

    2016-01-01

    Short stature has been associated with psychosocial impairments, but whether treatments and achieved height impact on health-related quality of life (HrQoL) and psychological functioning of children/adolescents is still controversial. This study aimed to examine the effects of height deviation and treatment status on psychosocial adaptation outcomes and to identify clinical and psychosocial determinants of internalizing/externalizing problems in a large cohort of short statured children/adolescents from seven European countries. Participants were 345 children aged 8-18 years with a clinical diagnosis of short stature and 421 parents of 4-18 year-old patients. Children and parents reported on psychological problems (Strengths and Difficulties Questionnaire), generic (KIDSCREEN) and condition-specific HrQoL (QoLISSY). According to analyses of covariance, children/adolescents with current short stature presented more parent-reported internalizing problems and lower self- and parent-reported condition-specific HrQoL, compared to patients with an achieved height above -2SD. Treated children self-reported better HrQoL than the untreated group. Hierarchical regression analysis showed that, rather than height-related clinical variables, children's sex, younger age and poorer HrQoL were the best predictors of psychological problems, explaining 39% of the variance in patient- and 42% in parent-reported internalizing problems, and 22% of the variance in patient- and 24% in parent-reported externalizing problems. Treatment status also moderated the negative links between patient-reported HrQoL and internalizing problems, explaining 2% of additional variance. These results suggest that children with current short stature are at greater risk for internalizing problems. Routine assessment of HrQoL in pediatric healthcare may help identify children for referral to specialized psychological assessment and intervention. PMID:27097033

  12. Associations between Psychological Problems and Quality of Life in Pediatric Short Stature from Patients’ and Parents’ Perspectives

    PubMed Central

    Bullinger, Monika; Sommer, Rachel; Rohenkohl, Anja Christine; Bernardino Da Silva, Neuza Maria

    2016-01-01

    Short stature has been associated with psychosocial impairments, but whether treatments and achieved height impact on health-related quality of life (HrQoL) and psychological functioning of children/adolescents is still controversial. This study aimed to examine the effects of height deviation and treatment status on psychosocial adaptation outcomes and to identify clinical and psychosocial determinants of internalizing/externalizing problems in a large cohort of short statured children/adolescents from seven European countries. Participants were 345 children aged 8–18 years with a clinical diagnosis of short stature and 421 parents of 4–18 year-old patients. Children and parents reported on psychological problems (Strengths and Difficulties Questionnaire), generic (KIDSCREEN) and condition-specific HrQoL (QoLISSY). According to analyses of covariance, children/adolescents with current short stature presented more parent-reported internalizing problems and lower self- and parent-reported condition-specific HrQoL, compared to patients with an achieved height above -2SD. Treated children self-reported better HrQoL than the untreated group. Hierarchical regression analysis showed that, rather than height–related clinical variables, children’s sex, younger age and poorer HrQoL were the best predictors of psychological problems, explaining 39% of the variance in patient- and 42% in parent-reported internalizing problems, and 22% of the variance in patient- and 24% in parent-reported externalizing problems. Treatment status also moderated the negative links between patient-reported HrQoL and internalizing problems, explaining 2% of additional variance. These results suggest that children with current short stature are at greater risk for internalizing problems. Routine assessment of HrQoL in pediatric healthcare may help identify children for referral to specialized psychological assessment and intervention. PMID:27097033

  13. Modulation of Epigenetic Targets for Anticancer Therapy: Clinicopathological Relevance, Structural Data and Drug Discovery Perspectives

    PubMed Central

    Andreol, Federico; Barbosa, Arménio Jorge Moura; Daniele Parenti, Marco; Rio, Alberto Del

    2013-01-01

    Research on cancer epigenetics has flourished in the last decade. Nevertheless growing evidence point on the importance to understand the mechanisms by which epigenetic changes regulate the genesis and progression of cancer growth. Several epigenetic targets have been discovered and are currently under validation for new anticancer therapies. Drug discovery approaches aiming to target these epigenetic enzymes with small-molecules inhibitors have produced the first pre-clinical and clinical outcomes and many other compounds are now entering the pipeline as new candidate epidrugs. The most studied targets can be ascribed to histone deacetylases and DNA methyltransferases, although several other classes of enzymes are able to operate post-translational modifications to histone tails are also likely to represent new frontiers for therapeutic interventions. By acknowledging that the field of cancer epigenetics is evolving with an impressive rate of new findings, with this review we aim to provide a current overview of pre-clinical applications of small-molecules for cancer pathologies, combining them with the current knowledge of epigenetic targets in terms of available structural data and drug design perspectives. PMID:23016851

  14. A Cultural Perspective on the Structure of Student Interest in Science

    NASA Astrophysics Data System (ADS)

    Ainley, Mary; Ainley, John

    2011-01-01

    In this paper, we examine the nature of interest in science as represented in the Programme for International Student Assessment (PISA) 2006 data. We discuss the interconnections between measures of knowledge, affect, and value as components of interest in science. Working from a perspective acknowledging that many of the models of motivation represented in the literature have been developed in Western countries, we investigated whether the ways that knowledge, affect, and value combine in the structure of students' interest in science might vary in line with historical and cultural traditions. Four countries were chosen to represent contrasting cultural values as defined in analyses of the World Values Surveys and the European Values Surveys-Colombia, Estonia, USA, and Sweden. Models are described showing variations in fit across the four countries. Efforts to increase the attractiveness of science to students should take heed of the fact that all models indicated a central role for enjoyment of science in the paths linking personal value, interest, and current science activities with intentions for future participation in science. Differences in the strength of the associations between science knowledge and interest in science support the proposition that the interconnections between knowledge, affect, and value need to be understood in relation to students' broader historical and cultural context.

  15. Factor structure of the adolescent coping orientation for problem experiences in Spanish adolescents.

    PubMed

    Forns, Maria; Kirchner, Teresa; Peró, Maribel; Pont, Elisenda; Abad, Judit; Soler, Laia; Paretilla, Claudia

    2013-06-01

    The present study aimed to identify the best structure of the Adolescent Coping Orientation for Problem Experiences when applied to Spanish adolescents. A confirmatory factor analysis of five previous factor structures was conducted. As the data did not fit previous factor models, two exploratory factor analyses (first- and second-order) were carried out to identify the structure for Spanish adolescents and to analyse its criterion validity in relation to mental health, which was assessed by means of the Youth Self-Report. A first-wave sample of 1,152 secondary education pupils (645 boys, 56%; 507 girls, 44%; M age = 14.4 yr., SD = 1.4) was involved in the confirmatory and exploratory factor analyses. A second-wave sample of = 374 secondary education pupils (188 boys, 50.5%; 186 girls, 49.5%; M age = 15.4 yr., SD = 1.1) was used to assess criterion validity. The results yielded eight first-order factors with Cronbach's alpha ranging from .63 to .79, and two second-order factors that replicated the Approach and Avoidance focus of coping. The paper discusses both the content of the extracted factors and mental health issues. PMID:24245077

  16. Design of a Dual-Mapping Learning Approach for Problem Solving and Knowledge Construction in Ill-Structured Domains

    ERIC Educational Resources Information Center

    Wu, Bian; Wang, Minhong; Spector, J. Michael; Yang, Stephen J. H.

    2013-01-01

    Problem solving has been increasingly used as an important approach to learning especially in ill-structured domains. It is assumed that knowledge can be better consolidated and extended through problem-solving experience. However, many learners do not have the ability to separate general knowledge from specific cases, which inhibits successful…

  17. Validation Study of a Method for Assessing Complex Ill-Structured Problem Solving by Using Causal Representations

    ERIC Educational Resources Information Center

    Eseryel, Deniz; Ifenthaler, Dirk; Ge, Xun

    2013-01-01

    The important but little understood problem that motivated this study was the lack of research on valid assessment methods to determine progress in higher-order learning in situations involving complex and ill-structured problems. Without a valid assessment method, little progress can occur in instructional design research with regard to designing…

  18. Structural geology practice and learning, from the perspective of cognitive science

    NASA Astrophysics Data System (ADS)

    Shipley, Thomas F.; Tikoff, Basil; Ormand, Carol; Manduca, Cathy

    2013-09-01

    Spatial ability is required by practitioners and students of structural geology and so, considering spatial skills in the context of cognitive science has the potential to improve structural geology teaching and practice. Spatial thinking skills may be organized using three dichotomies, which can be linked to structural geology practice. First, a distinction is made between separating (attending to part of a whole) and combining (linking together aspects of the whole). While everyone has a basic ability to separate and combine, experts attend to differences guided by experiences of rock properties in context. Second, a distinction is made between seeing the relations among multiple objects as separate items or the relations within a single object with multiple parts. Experts can flexibly consider relations among or between objects to optimally reason about different types of spatial problems. Third, a distinction is made between reasoning about stationary and moving objects. Experts recognize static configurations that encode a movement history, and create mental models of the processes that led to the static state. The observations and inferences made by a geologist leading a field trip are compared with the corresponding observations and inferences made by a cognitive psychologist interested in spatial learning. The presented framework provides a vocabulary for discussing spatial skills both within and between the fields of structural geology and cognitive psychology.

  19. Graph theory approach to the eigenvalue problem of large space structures

    NASA Technical Reports Server (NTRS)

    Reddy, A. S. S. R.; Bainum, P. M.

    1981-01-01

    Graph theory is used to obtain numerical solutions to eigenvalue problems of large space structures (LSS) characterized by a state vector of large dimensions. The LSS are considered as large, flexible systems requiring both orientation and surface shape control. Graphic interpretation of the determinant of a matrix is employed to reduce a higher dimensional matrix into combinations of smaller dimensional sub-matrices. The reduction is implemented by means of a Boolean equivalent of the original matrices formulated to obtain smaller dimensional equivalents of the original numerical matrix. Computation time becomes less and more accurate solutions are possible. An example is provided in the form of a free-free square plate. Linearized system equations and numerical values of a stiffness matrix are presented, featuring a state vector with 16 components.

  20. Method of adiabatic modes in studying problems of smoothly irregular open waveguide structures

    SciTech Connect

    Sevastianov, L. A.; Egorov, A. A.; Sevastyanov, A. L.

    2013-02-15

    Basic steps in developing an original method of adiabatic modes that makes it possible to solve the direct and inverse problems of simulating and designing three-dimensional multilayered smoothly irregular open waveguide structures are described. A new element in the method is that an approximate solution of Maxwell's equations is made to obey 'inclined' boundary conditions at the interfaces between themedia being considered. These boundary conditions take into account the obliqueness of planes tangent to nonplanar boundaries between the media and lead to new equations for coupled vector quasiwaveguide hybrid adiabatic modes. Solutions of these equations describe the phenomenon of 'entanglement' of two linear polarizations of an irregular multilayered waveguide, the appearance of a new mode in an entangled state, and the effect of rotation of the polarization plane of quasiwaveguide modes. The efficiency of the method is demonstrated by considering the example of numerically simulating a thin-film generalized waveguide Lueneburg lens.

  1. School Attendance Problems and Youth Psychopathology: Structural Cross-Lagged Regression Models in Three Longitudinal Datasets

    PubMed Central

    Wood, Jeffrey J.; Lynne, Sarah D.; Langer, David A.; Wood, Patricia A.; Clark, Shaunna L.; Eddy, J. Mark; Ialongo, Nicholas

    2011-01-01

    This study tests a model of reciprocal influences between absenteeism and youth psychopathology using three longitudinal datasets (Ns= 20745, 2311, and 671). Participants in 1st through 12th grades were interviewed annually or bi-annually. Measures of psychopathology include self-, parent-, and teacher-report questionnaires. Structural cross-lagged regression models were tested. In a nationally representative dataset (Add Health), middle school students with relatively greater absenteeism at study year 1 tended towards increased depression and conduct problems in study year 2, over and above the effects of autoregressive associations and demographic covariates. The opposite direction of effects was found for both middle and high school students. Analyses with two regionally representative datasets were also partially supportive. Longitudinal links were more evident in adolescence than in childhood. PMID:22188462

  2. Tackling pseudosymmetry problems in electron backscatter diffraction (EBSD) analyses of perovskite structures

    NASA Astrophysics Data System (ADS)

    Mariani, Elisabetta; Kaercher, Pamela; Mecklenburgh, Julian; Wheeler, John

    2016-04-01

    Perovskite minerals form an important mineral group that has applications in Earth science and emerging alternative energy technologies, however crystallographic quantification of these minerals with electron backscatter diffraction (EBSD) is not accurate due to pseudosymmetry problems. The silicate perovskite Bridgmanite, (Mg,Fe)SiO3, is understood to be the dominant phase in the Earth's lower mantle. Gaining insight into its physical and rheological properties is therefore vital to understand the dynamics of the Earth's deep interior. Rock deformation experiments on analogue perovskite phases, for example (Ca,Sr)TiO3, combined with quantitative microstructural analyses of the recovered samples by EBSD, yield datasets that can reveal what deformation mechanisms may dominate the flow of perovskite in the lower mantle. Additionally, perovskite structures have important technological applications as new, suitable cathodes for the operation of more efficient and environmentally-friendly solid oxide fuel cells (SOFC). In recent years they have also been recognised as a potential substitute for silicon in the next generation of photovoltaic cells for the construction of economic and energy efficient solar panels. EBSD has the potential to be a valuable tool for the study of crystal orientations achieved in perovskite substrates as crystal alignment has a direct control on the properties of these materials. However, perovskite structures currently present us with challenges during the automated indexing of Kikuchi bands in electron backscatter diffraction patterns (EBSPs). Such challenges are represented by the pseudosymmetric character of perovskites, where atoms are subtly displaced (0.005 nm to 0.05 nm) from their higher symmetry positions. In orthorhombic Pbnm perovskites, for example, pseudosymmetry may be evaluated from the c/a unit cell parameter ratio, which is very close to 1. Two main types of distortions from the higher symmetry structure are recognised: a

  3. Lagrangian coherent structures in the planar elliptic restricted three-body problem

    NASA Astrophysics Data System (ADS)

    Gawlik, Evan S.; Marsden, Jerrold E.; Du Toit, Philip C.; Campagnola, Stefano

    2009-03-01

    This study investigates Lagrangian coherent structures (LCS) in the planar elliptic restricted three-body problem (ER3BP), a generalization of the circular restricted three-body problem (CR3BP) that asks for the motion of a test particle in the presence of two elliptically orbiting point masses. Previous studies demonstrate that an understanding of transport phenomena in the CR3BP, an autonomous dynamical system (when viewed in a rotating frame), can be obtained through analysis of the stable and unstable manifolds of certain periodic solutions to the CR3BP equations of motion. These invariant manifolds form cylindrical tubes within surfaces of constant energy that act as separatrices between orbits with qualitatively different behaviors. The computation of LCS, a technique typically applied to fluid flows to identify transport barriers in the domains of time-dependent velocity fields, provides a convenient means of determining the time-dependent analogues of these invariant manifolds for the ER3BP, whose equations of motion contain an explicit dependency on the independent variable. As a direct application, this study uncovers the contribution of the planet Mercury to the Interplanetary Transport Network, a network of tubes through the solar system that can be exploited for the construction of low-fuel spacecraft mission trajectories.

  4. Beyond static structures: Putting forth REMD as a tool to solve problems in computational organic chemistry.

    PubMed

    Petraglia, Riccardo; Nicolaï, Adrien; Wodrich, Matthew D; Ceriotti, Michele; Corminboeuf, Clemence

    2016-01-01

    Computational studies of organic systems are frequently limited to static pictures that closely align with textbook style presentations of reaction mechanisms and isomerization processes. Of course, in reality chemical systems are dynamic entities where a multitude of molecular conformations exists on incredibly complex potential energy surfaces (PES). Here, we borrow a computational technique originally conceived to be used in the context of biological simulations, together with empirical force fields, and apply it to organic chemical problems. Replica-exchange molecular dynamics (REMD) permits thorough exploration of the PES. We combined REMD with density functional tight binding (DFTB), thereby establishing the level of accuracy necessary to analyze small molecular systems. Through the study of four prototypical problems: isomer identification, reaction mechanisms, temperature-dependent rotational processes, and catalysis, we reveal new insights and chemistry that likely would be missed using static electronic structure computations. The REMD-DFTB methodology at the heart of this study is powered by i-PI, which efficiently handles the interface between the DFTB and REMD codes.

  5. ALPS: The Age-Layered Population Structure for Reducing the Problem of Premature Convergence

    NASA Technical Reports Server (NTRS)

    Hornby, Gregory S.

    2006-01-01

    To reduce the problem of premature convergence we define a new attribute of an individual, its age, and propose the Age-Layered Population Structure (ALPS), in which age is used to restrict competition and breeding between members of the population. ALPS differs from a typical EA by segregating individuals into different age-layers by their age - a measure of how long the genetic material has been in the population - and by regularly replacing all individuals in the bottom layer with randomly generated ones. The introduction of new, randomly generated individuals at regular intervals results in an EA that is never completely converged and is always looking at new parts of the fitness landscape. By using age to restrict competition and breeding search is able to develop promising young individuals without them being dominated by older ones. We demonstrate the effectiveness of the ALPS algorithm on an antenna design problem in which evolution with ALPS produces antennas more than twice as good as does evolution with two other types of EAs. Further analysis shows that the ALPS model does allow the offspring of newly generated individuals to move the population out of mediocre local-optima to better parts of the fitness landscape.

  6. A systematic review of qualitative research on the contributory factors leading to medicine-related problems from the perspectives of adult patients with cardiovascular diseases and diabetes mellitus

    PubMed Central

    Al Hamid, A; Ghaleb, M; Aljadhey, H; Aslanpour, Z

    2014-01-01

    Objectives To synthesise contributing factors leading to medicine-related problems (MRPs) in adult patients with cardiovascular diseases and/or diabetes mellitus from their perspectives. Design A systematic literature review of qualitative studies regarding the contributory factors leading to MRPs, medication errors and non-adherence, followed by a thematic synthesis of the studies. Data sources We screened Pubmed, EMBASE, ISI Web of Knowledge, PsycInfo, International Pharmaceutical Abstract and PsycExtra for qualitative studies (interviews, focus groups and questionnaires of a qualitative nature). Review methods Thematic synthesis was achieved by coding and developing themes from the findings of qualitative studies. Results The synthesis yielded 21 studies that satisfied the inclusion and exclusion criteria. Three themes emerged that involved contributing factors to MRPs: patient-related factors including socioeconomic factors (beliefs, feeling victimised, history of the condition, lack of finance, lack of motivation and low self-esteem) and lifestyle factors (diet, lack of exercise/time to see the doctor, obesity, smoking and stress), medicine-related factors (belief in natural remedies, fear of medicine, lack of belief in medicines, lack of knowledge, non-adherence and polypharmacy) and condition-related factors (lack of knowledge/understanding, fear of condition and its complications, and lack of control). Conclusions MRPs represent a major health threat, especially among adult patients with cardiovascular diseases and/or diabetes mellitus. The patients’ perspectives uncovered hidden factors that could cause and/or contribute to MRPs in these groups of patients. PMID:25239295

  7. Modular localization and the holistic structure of causal quantum theory, a historical perspective

    NASA Astrophysics Data System (ADS)

    Schroer, Bert

    2015-02-01

    Recent insights into the conceptual structure of localization in QFT (modular localization) led to clarifications of old unsolved problems. The oldest one is the Einstein-Jordan conundrum which led Jordan in 1925 to the discovery of quantum field theory. This comparison of fluctuations in subsystems of heat bath systems (Einstein) with those resulting from the restriction of the QFT vacuum state to an open subvolume (Jordan) leads to a perfect analogy; the globally pure vacuum state becomes upon local restriction a strongly impure KMS state. This phenomenon of localization-caused thermal behavior as well as the vacuum-polarization clouds at the causal boundary of the localization region places localization in QFT into a sharp contrast with quantum mechanics and justifies the attribute "holstic". In fact it positions the E-J Gedankenexperiment into the same conceptual category as the cosmological constant problem and the Unruh Gedankenexperiment. The holistic structure of QFT resulting from "modular localization" also leads to a revision of the conceptual origin of the crucial crossing property which entered particle theory at the time of the bootstrap S-matrix approach but suffered from incorrect use in the S-matrix settings of the dual model and string theory. The new holistic point of view, which strengthens the autonomous aspect of QFT, also comes with new messages for gauge theory by exposing the clash between Hilbert space structure and localization and presenting alternative solutions based on the use of stringlocal fields in Hilbert space. Among other things this leads to a reformulation of the Englert-Higgs symmetry breaking mechanism.

  8. Effects of structural and dynamic family characteristics on the development of depressive and aggressive problems during adolescence. The TRAILS study.

    PubMed

    Sijtsema, J J; Oldehinkel, A J; Veenstra, R; Verhulst, F C; Ormel, J

    2014-06-01

    Both structural (i.e., SES, familial psychopathology, family composition) and dynamic (i.e., parental warmth and rejection) family characteristics have been associated with aggressive and depressive problem development. However, it is unclear to what extent (changes in) dynamic family characteristics have an independent effect on problem development while accounting for stable family characteristics and comorbid problem development. This issue was addressed by studying problem development in a large community sample (N = 2,230; age 10-20) of adolescents using Linear Mixed models. Paternal and maternal warmth and rejection were assessed via the Egna Minnen Beträffande Uppfostran for Children (EMBU-C). Aggressive and depressive problems were assessed via subscales of the Youth/Adult Self-Report. Results showed that dynamic family characteristics independently affected the development of aggressive problems. Moreover, maternal rejection in preadolescence and increases in paternal rejection were associated with aggressive problems, whereas decreases in maternal rejection were associated with decreases in depressive problems over time. Paternal and maternal warmth in preadolescence was associated with fewer depressive problems during adolescence. Moreover, increases in paternal warmth were associated with fewer depressive problems over time. Aggressive problems were a stable predictor of depressive problems over time. Finally, those who increased in depressive problems became more aggressive during adolescence, whereas those who decreased in depressive problems became also less aggressive. Besides the effect of comorbid problems, problem development is to a large extent due to dynamic family characteristics, and in particular to changes in parental rejection, which leaves much room for parenting-based interventions. PMID:24043499

  9. Existence of a weak solution to a fluid-elastic structure interaction problem with the Navier slip boundary condition

    NASA Astrophysics Data System (ADS)

    Muha, Boris; Čanić, Sunčica

    2016-06-01

    We study a nonlinear, moving boundary fluid-structure interaction (FSI) problem between an incompressible, viscous Newtonian fluid, modeled by the 2D Navier-Stokes equations, and an elastic structure modeled by the shell or plate equations. The fluid and structure are coupled via the Navier slip boundary condition and balance of contact forces at the fluid-structure interface. The slip boundary condition might be more realistic than the classical no-slip boundary condition in situations, e.g., when the structure is "rough", and in modeling FSI dynamics near, or at a contact. Cardiovascular tissue and cell-seeded tissue constructs, which consist of grooves in tissue scaffolds that are lined with cells, are examples of "rough" elastic interfaces interacting with an incompressible, viscous fluid. The problem of heart valve closure is an example of a FSI problem with a contact involving elastic interfaces. We prove the existence of a weak solution to this class of problems by designing a constructive proof based on the time discretization via operator splitting. This is the first existence result for fluid-structure interaction problems involving elastic structures satisfying the Navier slip boundary condition.

  10. Problem-Based Learning at the Receiving End: A "Mixed Methods" Study of Junior Medical Students' Perspectives

    ERIC Educational Resources Information Center

    Maudsley, Gillian; Williams, Evelyn M. I.; Taylor, David C. M.

    2008-01-01

    Qualitative insights about students' personal experience of inconsistencies in implementation of problem-based learning (PBL) might help refocus expert discourse about good practice. Aim: This study explored how junior medical students conceptualize: PBL; good tutoring; and less effective sessions. Methods: Participants comprised junior medical…

  11. Finding help for sexual problems after prostate cancer treatment: a phone survey of men's and women's perspectives.

    PubMed

    Neese, Leah E; Schover, Leslie R; Klein, Eric A; Zippe, Craig; Kupelian, Patrick A

    2003-01-01

    As part of a larger postal survey, 320 survivors of prostate cancer who reported they were likely to seek help in the next year for a sexual problem were interviewed by phone about their strategies for finding help and the types of treatment that would help resolve post-cancer sexual problems. In addition, 164 sexual partners (including 160 wives, three female partners in committed relationships, and one gay male partner) were interviewed. Educational materials were used by patients and partners to answer questions about sexual dysfunction but were less useful in helping to find professional referrals or in actually resolving sexual problems, particularly for African-American couples. Men's preferred method of finding help was to consult a urologist or prostate cancer specialist to find a medical treatment for erectile dysfunction. Ninety-one percent of men had already tried to find medical help for erectile dysfunction, but previous attempts remained unsuccessful. Men wanted an oral medication that would resolve their sexual problem naturally, without major side effects. Only 43% of men said their partners had encouraged them to find help, and indeed a large minority of women had resigned themselves to having unsatisfying sex lives. These data suggest that including the partner in counseling about medical treatments for sexual function, and giving both men and partners realistic expectations about the limitations of existing treatments could boost the success of sexual rehabilitation after prostate cancer.

  12. A Perspective on AIDS: A Catastrophic Disease but a Symptom of Deeper Problems in the Black Community.

    ERIC Educational Resources Information Center

    McBride, Andrew D.

    1988-01-01

    Acquired Immune Deficiency Syndrome (AIDS) is undisputedly the most significant public health problem facing the Black community today. From the outset, it was apparent that the disease disproportionately affected Blacks. In 1981, when AIDS was first identified, 21.5 percent of the first 107 cases were Blacks and Hispanics. This report discusses…

  13. Interagency Collaboration in Vocational Rehabilitation for Persons with Mental Health Problems: The Perspective of the Service Users and the Professionals

    ERIC Educational Resources Information Center

    Germundsson, Per; Hillborg, Helene; Danermark, Berth

    2011-01-01

    There is an aspiration and policy within the European Union to fully involve persons with disabilities in the community; this implies an opportunity to gainful employment. A large percentage of disabled persons remain unemployed despite this policy, especially persons with mental health problems. This study aims at investigating how people with…

  14. Perspectives and problems on quality of nursing care: an overview of contributions from North America and recent developments in Europe.

    PubMed

    van Maanen, H M

    1979-07-01

    The author focuses on the quality of nursing care and discusses the major problems inherent in control of the quality of nursing care. The concept of quality is analysed and the approaches of health care professionals to the concept are discussed. An overview of the American contribution to the relevant research is presented together with ongoing deveopments in Europe.

  15. English for Academic Study, With Special Reference to Science and Technology: Problems and Perspectives. An ETIC Occasional Paper.

    ERIC Educational Resources Information Center

    British Council, London (England). English-Teaching Information Centre.

    The four articles in this volume address themselves to issues in the teaching of English for science and technology (EST). H.G. Widdowson, in "EST in Theory and Practice," argues that teaching that is not informed by a functional approach to language can oversimplify pedagogical problems. "Designing English for Science and Technology (EST)…

  16. The Effect of Multiple Scaffolding Tools on Students' Understanding, Consideration of Different Perspectives, and Misconceptions of a Complex Problem

    ERIC Educational Resources Information Center

    Zydney, Janet Mannheimer

    2010-01-01

    This study investigated the effectiveness of multiple scaffolding tools in helping students understand a complex problem. In order to support students with this task, a multimedia learning environment was developed based on the cognitive flexibility theory (CFT) and scaffolding through computer-based tools. Seventy-nine 10th-grade students in an…

  17. On Index Structures in Hybrid Metaheuristics for Routing Problems with Hard Feasibility Checks: An Application to the 2-Dimensional Loading Vehicle Routing Problem

    NASA Astrophysics Data System (ADS)

    Strodl, Johannes; Doerner, Karl F.; Tricoire, Fabien; Hartl, Richard F.

    In this paper we study the impact of different index structures used within hybrid solution approaches for vehicle routing problems with hard feasibility checks. We examine the case of the vehicle routing problem with two-dimensional loading constraints, which combines the loading of freight into the vehicles and the routing of the vehicles to satisfy the demands of the customers. The problem is solved by a variable neighborhood search for the routing part, in which we embed an exact procedure for the loading subproblem. The contribution of the paper is threefold: i) Four different index mechanisms for managing the subproblems are implemented and tested. It is shown that simple index structures tend to lead to better solutions than more powerful albeit complex ones, when using the same runtime limits. ii) The problem of balancing the CPU budget between exploration of different solutions and exact solution of the loading subproblem is investigated; experiments show that solving exactly hard subproblems can lead to better solution quality over the whole solution process. iii) New best results are presented on existing benchmark instances.

  18. QUANTITATIVE STRUCTURE-ACTIVITY RELATIONSHIP METHODS: PERSPECTIVES ON DRUG DISCOVERY AND TOXICOLOGY. (R826133)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  19. Designing a Beryllium-Free Deep-Ultraviolet Nonlinear Optical Material without a Structural Instability Problem.

    PubMed

    Zhao, Sangen; Kang, Lei; Shen, Yaoguo; Wang, Xiaodong; Asghar, Muhammad Adnan; Lin, Zheshuai; Xu, Yingying; Zeng, Siyuan; Hong, Maochun; Luo, Junhua

    2016-03-01

    A beryllium-free deep-ultraviolet (deep-UV) nonlinear optical (NLO) material K3Ba3Li2Al4B6O20F is developed mainly by the element substitution of Be for Al and Li from Sr2Be2B2O7 that was considered as one of the most promising deep-UV NLO materials. K3Ba3Li2Al4B6O20F preserves the structural merits of Sr2Be2B2O7 and thus exhibits no layering growth tendency and possesses the optical properties required for deep-UV NLO applications, including deep-UV transparency, phase-matchability, and sufficiently large second-harmonic generation (1.5 × KH2PO4). Furthermore, it overcomes the structural instability problem of Sr2Be2B2O7, which is confirmed by the obtainment of large single crystals and phonon dispersion calculations. These attributes make it very attractive for next-generation deep-UV NLO materials. The substitution of Be for Al and Li in beryllium borates provides a new opportunity to design beryllium-free deep-UV NLO materials with good performance.

  20. Designing a Beryllium-Free Deep-Ultraviolet Nonlinear Optical Material without a Structural Instability Problem.

    PubMed

    Zhao, Sangen; Kang, Lei; Shen, Yaoguo; Wang, Xiaodong; Asghar, Muhammad Adnan; Lin, Zheshuai; Xu, Yingying; Zeng, Siyuan; Hong, Maochun; Luo, Junhua

    2016-03-01

    A beryllium-free deep-ultraviolet (deep-UV) nonlinear optical (NLO) material K3Ba3Li2Al4B6O20F is developed mainly by the element substitution of Be for Al and Li from Sr2Be2B2O7 that was considered as one of the most promising deep-UV NLO materials. K3Ba3Li2Al4B6O20F preserves the structural merits of Sr2Be2B2O7 and thus exhibits no layering growth tendency and possesses the optical properties required for deep-UV NLO applications, including deep-UV transparency, phase-matchability, and sufficiently large second-harmonic generation (1.5 × KH2PO4). Furthermore, it overcomes the structural instability problem of Sr2Be2B2O7, which is confirmed by the obtainment of large single crystals and phonon dispersion calculations. These attributes make it very attractive for next-generation deep-UV NLO materials. The substitution of Be for Al and Li in beryllium borates provides a new opportunity to design beryllium-free deep-UV NLO materials with good performance. PMID:26889570

  1. Key Problems in Organizing and Structuring University Research in Vietnam: The Lack of an Effective Research "Behaviour Formalization" System

    ERIC Educational Resources Information Center

    Nguyen, Huong Thi Lan; Meek, Vincent Lynn

    2016-01-01

    Structure and organization seems to be at the root of many of the questions raised about institutional behaviour; however, with respect to research on university capacity building, few studies have examined research organizational problems, particularly in developing countries. This study investigates academic reactions to the structure and…

  2. The soil-like substrate: problems and perspective of its use for higher plants cultivation in LSS

    NASA Astrophysics Data System (ADS)

    Tikhomirov, Alexander A.; Velichko, Vladimir; Nickolay Manukovsky, D..; Ushakova, Sofya; Kovalev, Vladimir

    Being the product of biological mineralization of plant wastes, the soil-like substrate (SLS) contains sufficient amount of nutrients required for plant growth and development. The multiple experiments carried out at the IBP SB RAS demonstrated the SLS fitness for cultivation of higher plant of phototrophic unit in biological-technical life support systems (BTLSS). Together with it, some problems demanding further investigations and solutions had revealed. One of the cardinal problems was interlinked with a relatively low allowance of assimilable nitrogen in comparison with other elements contained in the SLS. Different problems arising under a durational plant cultivation on the SLS in a regime of multi-species uneven-aged conveyer is considered. The work attends considerable attention to analysis of questions occurring at plant cultivation on a reusable SLS that resulted in a yield decrease. The ways of more effective exploitation of the SLS both as a bioreactor for plant wastes mineralization and as a substrate for plant cultivation in a long-functioning BTLSS of an increased closure level of mass exchange processes are suggested.

  3. Parents' and Adolescents' Perspectives on Parenting: Evaluating Conceptual Structure, Measurement Invariance, and Criterion Validity.

    PubMed

    Janssens, Annelies; Goossens, Luc; Van Den Noortgate, Wim; Colpin, Hilde; Verschueren, Karine; Van Leeuwen, Karla

    2015-08-01

    Uncertainty persists regarding adequate measurement of parenting behavior during early adolescence. The present study aimed to clarify the conceptual structure of parenting by evaluating three different models that include support, psychological control, and various types of behavioral control (i.e., proactive, punitive, and harsh punitive control). Furthermore, we examined measurement invariance of parenting ratings by 1,111 Flemish adolescents from Grade 7 till 9, their mother, and father. Finally, criterion validity of parenting ratings was estimated in relation to adolescent problem behavior. Results supported a five-factor parenting model indicating multiple aspects of behavioral control, with punitive and harsh punitive control as more intrusive forms and proactive control as a more supportive form. Similar constructs were measured for adolescents, mothers, and fathers (i.e., configural and metric invariance), however on a different scale (i.e., scalar noninvariance). Future research and clinical practices should acknowledge these findings in order to fully grasp the parenting process.

  4. Factor structure and item level psychometrics of the Social Problem Solving Inventory-Revised: Short Form in traumatic brain injury.

    PubMed

    Li, Chih-Ying; Waid-Ebbs, Julia; Velozo, Craig A; Heaton, Shelley C

    2016-01-01

    Social problem-solving deficits characterise individuals with traumatic brain injury (TBI), and poor social problem solving interferes with daily functioning and productive lifestyles. Therefore, it is of vital importance to use the appropriate instrument to identify deficits in social problem solving for individuals with TBI. This study investigates factor structure and item-level psychometrics of the Social Problem Solving Inventory-Revised: Short Form (SPSI-R:S), for adults with moderate and severe TBI. Secondary analysis of 90 adults with moderate and severe TBI who completed the SPSI-R:S was performed. An exploratory factor analysis (EFA), principal components analysis (PCA) and Rasch analysis examined the factor structure and item-level psychometrics of the SPSI-R:S. The EFA showed three dominant factors, with positively worded items represented as the most definite factor. The other two factors are negative problem-solving orientation and skills; and negative problem-solving emotion. Rasch analyses confirmed the three factors are each unidimensional constructs. It was concluded that the total score interpretability of the SPSI-R:S may be challenging due to the multidimensional structure of the total measure. Instead, we propose using three separate SPSI-R:S subscores to measure social problem solving for the TBI population.

  5. Platelet-rich plasma therapy for knee joint problems: review of the literature, current practice and legal perspectives in Korea.

    PubMed

    Park, Yong-Geun; Han, Seung Beom; Song, Sang Jun; Kim, Tae Jin; Ha, Chul-Won

    2012-06-01

    Platelet-rich plasma (PRP) is a concentrate extract of platelets from autologous blood, and represents a possible treatment option for the stimulation and acceleration of soft-tissue healing and regeneration in orthopedics. Currently, the availability of devices for outpatient preparation and delivery contributes to the increase in the clinical use of PRP therapy in practical setting of orthopedic fields. However, there is still paucity of scientific evidence in the literature to prove efficacy of PRP therapy for the treatment of ligament or tendon problems around the knee joint. Moreover, strong evidence from well-designed clinical trials to support the PRP therapy for osteoarthritis of the knee joint is yet scanty in the literature. Scientific studies need to be performed to assess clinical indications, efficacy, and safety of PRP, and this will require high powered randomized controlled trials. Nonetheless, some hospitals exaggeratedly advertise PRP procedures as the ultimate treatment and a novel technology with abundant scientific evidence for the treatment of knee problems. As a matter of fact, PRP protocols are currently approved only for use in clinical trials and research, and are not allowed for treatment purpose by any institutions in Korea. At present, clinical use of PRP therapy for ligament or tendon problems or osteoarthritis of knee joint is defined as illegal medical practice, regardless of whether it is performed as a sole procedure or as a part of prolotherapy, because the safety and validity are not yet approved by the Ministry of Health and Welfare and Health Insurance Review and Assessment Service. Practicing physicians should remember that injection of PRP to patients by imposing medical charge is still illegal as per the current medical law in Korea. PMID:22708106

  6. [Gender identity disorder and related sexual behavior problems in children and adolescents: from the perspective of development and child psychiatry].

    PubMed

    Yamashita, Hiroshi

    2013-01-01

    exaggerates to gender-related problems. However, these views do not explain all cases; true comorbidity of ASD and GID should be considered. A full assessment including evaluation of the family, school, and social environment is essential as other emotional and behavioral problems are very common and unresolved issues in the child's environment are often present e. g., loss. Separation problems are particularly common in the younger group. Intervention should aim to assist development, particularly that of gender identity. It should focus on ameliorating the comorbid problems and difficulties in the child's life and reducing the distress experienced by the child.

  7. Error and Uncertainty in the Structure of a Model: A Philosophical Perspective (Invited)

    NASA Astrophysics Data System (ADS)

    Beck, B.; Lin, Z.

    2009-12-01

    Working before the advent of the now commonplace computational model, American pragmatist philosopher Lewis held that there were three elements to the growth of knowledge: the set of concepts; the given data; and those acts which reconcile the data with the concepts. Today, we might call this third element the matter of system identification, or, more precisely, model structure identification. We review briefly the historical developments in dealing with structural error, structural uncertainty, and structural change in models of the behavior of environmental systems. Our focus, however, is on scientific visualization of model structure and the way in which such can assist the process of model structure identification. It is obvious that there has been literally a huge expansion over the decades in our capacity to realize Lewis’s “set of concepts”, as in the ever expanding scope and complexity of our computer-based models, i.e., very high order models (or VHOMs). Together with the oncoming environmental cyber-infrastructure, including novel sensors and sensor technologies, the Environmental Observatories (EOs) of the US National Science Foundation (NSF) share the collective ambition of bringing unprecedented streams of observations to bear on Environmental Science in the decades to come. In short, we can expect a yet further massive expansion in the “given data”. Under such prospects, it has to be the case that Lewis’s “acts” — system identification and, more especially, model structure identification — will likewise be presented with new opportunities for progress and (just as much) confronted with new barriers to be overcome in achieving such progress. Current developments in addressing some of these problems of model structure identification are illustrated using a field case study of nutrient cycling and biomass dynamics in a manipulated aquaculture pond and a simple, hypothetical, biotechnical system. We employ the latter for sharpening our

  8. Nonlinear dynamics and neo-piagetian theories in problem solving: perspectives on a new epistemology and theory development.

    PubMed

    Stamovlasis, Dimitrios

    2011-04-01

    In this study, an attempt is made to integrate Nonlinear Dynamical Systems theory and neo-Piagetian theories applied to creative mental processes, such as problem solving. A catastrophe theory model is proposed, which implements three neo-Piagetian constructs as controls: the functional M-capacity as asymmetry and logical thinking and the degree of field dependence independence as bifurcation. Data from achievement scores of students in tenth grade physics were analyzed using dynamic difference equations and statistical regression techniques. The cusp catastrophe model proved superior comparing to the pre-post linear counterpart and demonstrated nonlinearity at the behavioral level. The nonlinear phenomenology, such as hysteresis effects and bifurcation, is explained by an analysis, which provides a causal interpretation via the mathematical theory of self-organization and thus building bridges between NDS-theory concepts and neo-Piagetian theories. The contribution to theory building is made, by also addressing the emerging philosophical, - ontological and epistemological- questions about the processes of problem solving and creativity.

  9. Counselling teenage girls on problems related to the 'protection of family honour' from the perspective of school nurses and counsellors.

    PubMed

    Alizadeh, Venus; Törnkvist, Lena; Hylander, Ingrid

    2011-09-01

    Approximately 1,500 young immigrant women living in Sweden sought help from various public organisations during 2004 due to problems related to Protection of Family Honour (PFH). Often they seek help from school nurses and counsellors. Information on how the school nurses and counsellors manage this complex PFH phenomenon is limited in Sweden. The aim was to generate a theoretical model that illuminates the experiences of school counsellors and school nurses counselling teenage girls, who worry about problems related to protection of family honour. Data were collected through individual interviews of the school welfare staff. The study subjects included welfare staff from six upper-secondary schools consisting of four nurses and six counsellors. Grounded theory methods were used to generate new knowledge as this is a new field of research. The staff's main goal was to provide the best support and help for the teenage girls. In addition, they wanted to be true to their professional ethics and values. However, this was difficult and created professional dilemmas because some teenage girls prevented them from doing what they thought was needed to support the teenage girls and protect them from violence. As a result, staff sometimes felt hampered, unable to help or able to help only in ways hidden from the teenage girls' families.

  10. Structuring Word Problems for Diagnostic Teaching: Helping Teachers Meet the Needs of Children with Mild Disabilities.

    ERIC Educational Resources Information Center

    Parmar, Rene S.; Cawley, John F.

    1994-01-01

    Matrix organization can be used to construct math word problems for children with mild disabilities. Matrix organization specifies the characteristics of problems, such as problem theme or setting, operations, level of computation complexity, reading vocabulary level, and need for classification. A sample scope and sequence and 16 sample word…

  11. Psychosocial Problems among Truant Youths: A Multi-Group, Exploratory Structural Equation Modeling Analysis

    ERIC Educational Resources Information Center

    Dembo, Richard; Briones-Robinson, Rhissa; Barrett, Kimberly; Winters, Ken C.; Ungaro, Rocio; Karas, Lora; Wareham, Jennifer; Belenko, Steven

    2012-01-01

    Truant youths represent a critical group needing problem-oriented research and involvement in effective services. The limited number of studies on the psychosocial functioning of truant youths have focused on one or a few problem areas, rather than examining comorbid problem behaviors. The present study addresses the need to examine the…

  12. The Structure of Experience Acquired While Learning to Solve a Class of Problems.

    ERIC Educational Resources Information Center

    Egan, Dennis Edmund

    In this study three issues related to "expert" problem solving were studied; the problems considered were based on Tower of Hanoi puzzles. A computer simulation was proposed and tested, effects of cues on subjects' performance were studied, and inter-problem transfer was analyzed. Four predictions were posed for the simulation study. Two of these…

  13. Low Dimensional Tools for Flow-Structure Interaction Problems: Application to Micro Air Vehicles

    NASA Technical Reports Server (NTRS)

    Schmit, Ryan F.; Glauser, Mark N.; Gorton, Susan A.

    2003-01-01

    A low dimensional tool for flow-structure interaction problems based on Proper Orthogonal Decomposition (POD) and modified Linear Stochastic Estimation (mLSE) has been proposed and was applied to a Micro Air Vehicle (MAV) wing. The method utilizes the dynamic strain measurements from the wing to estimate the POD expansion coefficients from which an estimation of the velocity in the wake can be obtained. For this experiment the MAV wing was set at five different angles of attack, from 0 deg to 20 deg. The tunnel velocities varied from 44 to 58 ft/sec with corresponding Reynolds numbers of 46,000 to 70,000. A stereo Particle Image Velocimetry (PIV) system was used to measure the wake of the MAV wing simultaneously with the signals from the twelve dynamic strain gauges mounted on the wing. With 20 out of 2400 POD modes, a reasonable estimation of the flow flow was observed. By increasing the number of POD modes, a better estimation of the flow field will occur. Utilizing the simultaneously sampled strain gauges and flow field measurements in conjunction with mLSE, an estimation of the flow field with lower energy modes is reasonable. With these results, the methodology for estimating the wake flow field from just dynamic strain gauges is validated.

  14. Combined aerodynamic and structural dynamic problem emulating routines (CASPER): Theory and implementation

    NASA Technical Reports Server (NTRS)

    Jones, William H.

    1985-01-01

    The Combined Aerodynamic and Structural Dynamic Problem Emulating Routines (CASPER) is a collection of data-base modification computer routines that can be used to simulate Navier-Stokes flow through realistic, time-varying internal flow fields. The Navier-Stokes equation used involves calculations in all three dimensions and retains all viscous terms. The only term neglected in the current implementation is gravitation. The solution approach is of an interative, time-marching nature. Calculations are based on Lagrangian aerodynamic elements (aeroelements). It is assumed that the relationships between a particular aeroelement and its five nearest neighbor aeroelements are sufficient to make a valid simulation of Navier-Stokes flow on a small scale and that the collection of all small-scale simulations makes a valid simulation of a large-scale flow. In keeping with these assumptions, it must be noted that CASPER produces an imitation or simulation of Navier-Stokes flow rather than a strict numerical solution of the Navier-Stokes equation. CASPER is written to operate under the Parallel, Asynchronous Executive (PAX), which is described in a separate report.

  15. From video to computation of biological fluid-structure interaction problems

    NASA Astrophysics Data System (ADS)

    Dillard, Seth I.; Buchholz, James H. J.; Udaykumar, H. S.

    2016-04-01

    This work deals with the techniques necessary to obtain a purely Eulerian procedure to conduct CFD simulations of biological systems with moving boundary flow phenomena. Eulerian approaches obviate difficulties associated with mesh generation to describe or fit flow meshes to body surfaces. The challenges associated with constructing embedded boundary information, body motions and applying boundary conditions on the moving bodies for flow computation are addressed in the work. The overall approach is applied to the study of a fluid-structure interaction problem, i.e., the hydrodynamics of swimming of an American eel, where the motion of the eel is derived from video imaging. It is shown that some first-blush approaches do not work, and therefore, careful consideration of appropriate techniques to connect moving images to flow simulations is necessary and forms the main contribution of the paper. A combination of level set-based active contour segmentation with optical flow and image morphing is shown to enable the image-to-computation process.

  16. Limitations of cadaveric organ donation on judicial cases and problems confronted in autopsy: Istanbul data in comparative perspective.

    PubMed

    Arslan, M N; Esen Melez, I; Melez, D O; Cavlak, M; Gur, A

    2014-04-01

    Organ transplantation is one of the most important services of modern medicine to the humanity. In judicial death cases the interaction between judicial needs and transplantation needs is inevitable and both should be provided in a short time before the decomposition of the body. Thus, the description of this interaction and the algorithm which should be carried out to manage these cases are important. Aim of this study is to determine the problems confronted in forensic autopsies and to determine what to do for both judicial processes' and cadaveric organ donations' not becoming limited due to each other. With these aims, autopsy case archive of the Council of Forensic Medicine Istanbul Morgue Department was reviewed, between the years 2009 and 2011, to reveal the number of organ donors among autopsy cases and also to find out the judicial problems confronted during autopsies. Among 12,016 judicial death cases referred to Istanbul Morgue Department in 3 years, 35 cases were found to have undergone cadaveric solid organ harvesting procedure and 307 cases cornea-only harvesting procedure. Manner of deaths for organ donor cases were blunt trauma due to traffic accident in 20 cases, firearm injury in 3 cases, stabbing in 2 cases, suspicious criminal battery in 4 cases and fatal falls in 5 cases. Only 1 case was suspected to have died due to high dose insulin administration. Through the whole data presented in this study, it can be concluded that consulting with the Forensic Medicine Expert not only for the autopsies but also during the clinical process of a judicial case, who is a candidate to be an organ donor, is absolutely important. The early contribution of the Forensic Medicine Expert would provide help to plan both the judicial process and the transplantation process which needs urgent decisions. A Forensic Medicine Expert may be an organ harvest team member performing initial investigations on the cause of death and collecting some of the toxicological

  17. Iterative solution of multiple radiation and scattering problems in structural acoustics using the BL-QMR algorithm

    SciTech Connect

    Malhotra, M.

    1996-12-31

    Finite-element discretizations of time-harmonic acoustic wave problems in exterior domains result in large sparse systems of linear equations with complex symmetric coefficient matrices. In many situations, these matrix problems need to be solved repeatedly for different right-hand sides, but with the same coefficient matrix. For instance, multiple right-hand sides arise in radiation problems due to multiple load cases, and also in scattering problems when multiple angles of incidence of an incoming plane wave need to be considered. In this talk, we discuss the iterative solution of multiple linear systems arising in radiation and scattering problems in structural acoustics by means of a complex symmetric variant of the BL-QMR method. First, we summarize the governing partial differential equations for time-harmonic structural acoustics, the finite-element discretization of these equations, and the resulting complex symmetric matrix problem. Next, we sketch the special version of BL-QMR method that exploits complex symmetry, and we describe the preconditioners we have used in conjunction with BL-QMR. Finally, we report some typical results of our extensive numerical tests to illustrate the typical convergence behavior of BL-QMR method for multiple radiation and scattering problems in structural acoustics, to identify appropriate preconditioners for these problems, and to demonstrate the importance of deflation in block Krylov-subspace methods. Our numerical results show that the multiple systems arising in structural acoustics can be solved very efficiently with the preconditioned BL-QMR method. In fact, for multiple systems with up to 40 and more different right-hand sides we get consistent and significant speed-ups over solving the systems individually.

  18. School Structure and the Identity of Teacher Leaders: Perspectives of Principals and Teachers

    ERIC Educational Resources Information Center

    Angelle, Pamela S.; Schmid, Jessie B.

    2007-01-01

    This qualitative study examines the concept of teacher leadership from the perspective of those who practice it. Viewed through the lens of identity theory, analysis yielded five categories that define and describe a teacher leader--namely, as a decision maker, an educational role model, a positional designee, a supra-practitioner, and a…

  19. A Cultural Perspective on the Structure of Student Interest in Science

    ERIC Educational Resources Information Center

    Ainley, Mary; Ainley, John

    2011-01-01

    In this paper, we examine the nature of interest in science as represented in the Programme for International Student Assessment (PISA) 2006 data. We discuss the interconnections between measures of knowledge, affect, and value as components of interest in science. Working from a perspective acknowledging that many of the models of motivation…

  20. A review of maturation diets for mud crab genus Scylla broodstock: Present research, problems and future perspective.

    PubMed

    Azra, Mohamad N; Ikhwanuddin, Mhd

    2016-03-01

    Study of broodstock maturation diets is important in order to increase the quality of berried females, which indirectly improve the larval quantity in the hatchery production of cultured species. This paper reviewed the studies on the maturation diets for mud crab broodstock, genus Scylla and compared independently to identify their effect on reproductive performance and larval quality. The broodstock is usually caught from the wild and held in the spawning or maturation tank for further use of hatchery seed production. Mud crab broodstock was fed either natural diet, artificial diet or mixed diet. Trash fishes were commonly used as a natural feed for mud crab broodstock; meanwhile artificial diets are from formulated fish meal and various kinds of feed. The results indicated that mud crab broodstock has a high dietary requirement for lipids, fatty acids and protein which are to be used during the maturation and breeding processes. However, the natural diet produce better larval quality compared to the artificial diet. The mixed diet is the better diet which resulted in better reproductive performances such as growth, survival, fecundity and maturation processes. This review also discusses the problems in the previous studies for the potential future research to develop very high quality and cost-effective formulated diet for the enhancement of broodstock and seed production technology. Information from this review can be useful in developing a better quality of crustacean broodstock's diet for commercial hatchery production. PMID:26981008