WorldWideScience

Sample records for group dynamic issues

  1. The Dynamics of Hope and Motivations in Groups Working on Complex Societal Issues

    Directory of Open Access Journals (Sweden)

    Pia Andersson

    2016-01-01

    Full Text Available This paper reports results from a study of how participants’ sense of personal hope and motivation was affected by a facilitated process in which four groups of people worked on different complex social issues. The group interventions were designed to scaffold increased understanding of the complexity of the chosen issue. A method called The Integral Process for Working on Complex Issues was used in all of the groups. Issues addressed in the four groups were: neighborhood deterioration, lack of community engagement, the need for better strategies for communication between rescue service actors in critical life-and-death situations, and transition to a more environmentally sustainable city. The study investigated the participants’ self-reported changes in their levels of hope regarding the possibility of achieving positive results on the selected issue, and changes in their motivation to engage in work to that end. The data were gathered through interviews with individual group participants before and after the group process. The sessions supported group members to develop more awareness of the complexity of the issues, and to develop strategies for action. The study indicates that the discovery of new potential pathways to manage an issue, through a more comprehensive understanding of the complexity involved, was a key factor influencing levels of hope and motivation. Reports from participants showed that when the participants formulated concrete actions that made sense to them, then “particularized hope” emerged, as well as motivation to continue to engage. Thus, increased levels of hope about a delimited part of the issue were reported, while in some cases, participants reported having less hope about the issue complex as a whole.

  2. Group dynamics.

    Science.gov (United States)

    Scandiffio, A L

    1990-12-01

    Group dynamics play a significant role within any organization, culture, or unit. The important thing to remember with any of these structures is that they are made up of people--people with different ideas, motivations, background, and sometimes different agendas. Most groups, formal or informal, look for a leader in an effort to maintain cohesiveness of the unit. At times, that cultural bond must be developed; once developed, it must be nurtured. There are also times that one of the group no longer finds the culture comfortable and begins to act out behaviorally. It is these times that become trying for the leader as she or he attempts to remain objective when that which was once in the building phase of group cohesiveness starts to fall apart. At all times, the manager must continue to view the employee creating the disturbance as an integral part of the group. It is at this time that it is beneficial to perceive the employee exhibiting problem behaviors as a special employee, as one who needs the benefit of your experience and skills, as one who is still part of the group. It is also during this time that the manager should focus upon her or his own views in the area of power, communication, and the corporate culture of the unit that one has established before attempting to understand another's point of view. Once we understand our own motivation and accept ourselves, it is then that we may move on to offer assistance to another. Once we understand our insecurities recognizing staff dysfunction as a symptom of system dysfunction will not be so threatening to the concept of the manager that we perceive ourselves to be. It takes a secure person to admit that she or he favors staff before deciding to do something to change things. The important thing to know is that it can be done. The favored staff can find a new way of relating to others, the special employee can find new modes of behavior (and even find self-esteem in the process), the group can find new ways

  3. Supervision and group dynamics

    DEFF Research Database (Denmark)

    Hansen, Søren; Jensen, Lars Peter

    2004-01-01

     An important aspect of the problem based and project organized study at Aalborg University is the supervision of the project groups. At the basic education (first year) it is stated in the curriculum that part of the supervisors' job is to deal with group dynamics. This is due to the experience...... that many students are having difficulties with practical issues such as collaboration, communication, and project management. Most supervisors either ignore this demand, because they do not find it important or they find it frustrating, because they do not know, how to supervise group dynamics...... as well as at Aalborg University. The first visible result has been participating supervisors telling us that the course has inspired them to try supervising group dynamics in the future. This paper will explore some aspects of supervising group dynamics as well as, how to develop the Aalborg model...

  4. Beam dynamics group summary

    International Nuclear Information System (INIS)

    Peggs, S.

    1994-01-01

    This paper summarizes the activities of the beam dynamics working group of the LHC Collective Effects Workshop that was held in Montreux in 1994. It reviews the presentations that were made to the group, the discussions that ensued, and the consensuses that evolved

  5. Theoretical Issues in Clinical Social Group Work.

    Science.gov (United States)

    Randall, Elizabeth; Wodarski, John S.

    1989-01-01

    Reviews relevant issues in clinical social group practice including group versus individual treatment, group work advantages, approach rationale, group conditions for change, worker role in group, group composition, group practice technique and method, time as group work dimension, pretherapy training, group therapy precautions, and group work…

  6. Climate change and group dynamics

    NARCIS (Netherlands)

    Postmes, Tom

    2015-01-01

    The characteristics and views of people sceptical about climate change have been analysed extensively. A study now confirms that sceptics in the US have some characteristics of a social movement, but shows that the same group dynamics propel believers

  7. Modelling group dynamic animal movement

    DEFF Research Database (Denmark)

    Langrock, Roland; Hopcraft, J. Grant C.; Blackwell, Paul G.

    2014-01-01

    makes its movement decisions relative to the group centroid. The basic idea is framed within the flexible class of hidden Markov models, extending previous work on modelling animal movement by means of multi-state random walks. While in simulation experiments parameter estimators exhibit some bias......, to date, practical statistical methods which can include group dynamics in animal movement models have been lacking. We consider a flexible modelling framework that distinguishes a group-level model, describing the movement of the group's centre, and an individual-level model, such that each individual......Group dynamic movement is a fundamental aspect of many species' movements. The need to adequately model individuals' interactions with other group members has been recognised, particularly in order to differentiate the role of social forces in individual movement from environmental factors. However...

  8. Dynamical issues in combustion theory

    International Nuclear Information System (INIS)

    Fife, P.C.; Williams, F.

    1991-01-01

    This book looks at the world of combustion phenomena covering the following topics: modeling, which involves the elucidation of the essential features of a given phenomenon through physical insight and knowledge of experimental results, devising appropriate asymptotic and computational methods, and developing sound mathematical theories. Papers in this book describe how all of these challenges have been met for particular examples within a number of common combustion scenarios: reactive shocks, low Mach number premixed reactive flow, nonpremixed phenomena, and solid propellants. The types of phenomena examined are also diverse: the stability and other properties of steady structures, the long time dynamics of evolving solutions, properties of interfaces and shocks, including curvature effects, and spatio-temporal patterns

  9. Beam dynamics issues for linear colliders

    International Nuclear Information System (INIS)

    Ruth, R.D.

    1987-09-01

    In this paper we discuss various beam dynamics issues for linear colliders. The emphasis is to explore beam dynamics effects which lead to an effective dilution of the emittance of the beam and thus to a loss of luminosity. These considerations lead to various tolerances which are evaluated for a particular parameter set

  10. Succession Planning: Building a Successful Organization in a Dynamic Environment. Report from the Study Group, Institute on Rehabilitation Issues (27th, Washington, DC, May 2001).

    Science.gov (United States)

    Radtke, Jean, Ed.

    This book is a guide designed for rehabilitation agencies to plan for staff retirements and other turnover. It examines the process of succession planning, necessary tools, resources, and positioning the organization for future success. Chapters have the following titles: (1) "Succession Planning in a Dynamic Environment"; (2)…

  11. SCOR Working Group 137: "Global Patterns of Phytoplankton Dynamics in Coastal Ecosystems": An introduction to the special issue of Estuarine, Coastal and Shelf Science

    Science.gov (United States)

    Paerl, Hans W.; Yin, Kedong; O'Brien, Todd D.

    2015-09-01

    Phytoplankton form the base of most aquatic food webs and play a central role in assimilation and processing of carbon and nutrients, including nitrogen, phosphorus, silicon, iron and a wide range of trace elements (Reynolds, 2006). In the marine environment, estuarine and coastal ecosystems (jointly termed coastal here) are among the most productive, resourceful and dynamic habitats on Earth (Malone et al., 1999; Day et al., 2012). These ecosystems constitute only ∼10% of the global oceans' surface, but account for over 30% of its primary production (Day et al., 2012). They process vast amounts of nutrients, sediments, carbonaceous, and xenobiotic compounds generated in coastal watersheds, in which approximately 70% of the world's human population resides (Nixon, 1995; Vitousek et al., 1997; NOAA, 2013). Estuarine and coastal ecosystems are also strongly influenced by localized nutrient enrichment from coastal upwelling, with major impacts on the structure and function of phytoplankton communities and the food webs they support (Legendre and Rassoulzadegan, 2012; Paerl and Justić, 2012). In addition, introductions and invasions of exotic plant and animal species have led to significant "top down" mediated changes in phytoplankton community structure and function (Carlton, 1999; Thompson, 2005). Lastly, the coastal zone is the "front line" of climatically-induced environmental change, including warming, altered rainfall patterns, intensities and magnitudes (Trenberth, 2005; IPCC, 2012), which jointly impact phytoplankton community structure and function (Cloern and Jassby, 2012; Hall et al., 2013). The combined effects of these pressures translate into a myriad of changes in phytoplankton production and community structure along geomorphological and geographic gradients (Fig. 1), with cascading quantitative and qualitative impacts on biogeochemical cycling, food web structure and function, water quality and overall resourcefulness and sustainability of these

  12. Critical Issues in International Group Counseling

    Science.gov (United States)

    Bemak, Fred; Chung, Rita Chi-Ying

    2015-01-01

    Three-quarters of the world come from collectivistic group-oriented cultures. As the world becomes more globalized it is inevitable that group counseling will be a major choice of healing and psychological intervention internationally. However, a review of scholarly articles from "The Journal for Specialists in Group Work" and…

  13. Group performance and group learning at dynamic system control tasks

    International Nuclear Information System (INIS)

    Drewes, Sylvana

    2013-01-01

    Proper management of dynamic systems (e.g. cooling systems of nuclear power plants or production and warehousing) is important to ensure public safety and economic success. So far, research has provided broad evidence for systematic shortcomings in individuals' control performance of dynamic systems. This research aims to investigate whether groups manifest synergy (Larson, 2010) and outperform individuals and if so, what processes lead to these performance advantages. In three experiments - including simulations of a nuclear power plant and a business setting - I compare the control performance of three-person-groups to the average individual performance and to nominal groups (N = 105 groups per experiment). The nominal group condition captures the statistical advantage of aggregated group judgements not due to social interaction. First, results show a superior performance of groups compared to individuals. Second, a meta-analysis across all three experiments shows interaction-based process gains in dynamic control tasks: Interacting groups outperform the average individual performance as well as the nominal group performance. Third, group interaction leads to stable individual improvements of group members that exceed practice effects. In sum, these results provide the first unequivocal evidence for interaction-based performance gains of groups in dynamic control tasks and imply that employers should rely on groups to provide opportunities for individual learning and to foster dynamic system control at its best.

  14. Political Justice, Schooling and Issues of Group Identity

    Science.gov (United States)

    Keddie, Amanda

    2014-01-01

    This article explores issues associated with schooling and political justice. Such issues are understood in light of the contention surrounding how Western schooling contexts might best represent marginalised groups--in ways that accord them a political voice. The significance of group identity politics is explored drawing on international debates…

  15. Ethical Issues in the Research of Group Work

    Science.gov (United States)

    Goodrich, Kristopher M.; Luke, Melissa

    2017-01-01

    This article provides a primer for researchers exploring ethical issues in the research of group work. The article begins with an exploration of relevant ethical issues through the research process and current standards guiding its practice. Next, the authors identify resources that group work researchers can consult prior to constructing their…

  16. Narcissistic group dynamics of multiparty systems

    NARCIS (Netherlands)

    Schruijer, S.G.L.

    2015-01-01

    Purpose – This paper aims to introduce and illustrate the notion of narcissistic group dynamics. It is claimed that narcissism does not simply reside within individuals but can be characteristic of groups and social systems. In this case, the focus is on narcissistic dynamics in multiparty systems.

  17. Secure Group Communications for Large Dynamic Multicast Group

    Institute of Scientific and Technical Information of China (English)

    Liu Jing; Zhou Mingtian

    2003-01-01

    As the major problem in multicast security, the group key management has been the focus of research But few results are satisfactory. In this paper, the problems of group key management and access control for large dynamic multicast group have been researched and a solution based on SubGroup Secure Controllers (SGSCs) is presented, which solves many problems in IOLUS system and WGL scheme.

  18. Group Dynamics in Automatic Imitation.

    Science.gov (United States)

    Gleibs, Ilka H; Wilson, Neil; Reddy, Geetha; Catmur, Caroline

    Imitation-matching the configural body movements of another individual-plays a crucial part in social interaction. We investigated whether automatic imitation is not only influenced by who we imitate (ingroup vs. outgroup member) but also by the nature of an expected interaction situation (competitive vs. cooperative). In line with assumptions from Social Identity Theory), we predicted that both social group membership and the expected situation impact on the level of automatic imitation. We adopted a 2 (group membership target: ingroup, outgroup) x 2 (situation: cooperative, competitive) design. The dependent variable was the degree to which participants imitated the target in a reaction time automatic imitation task. 99 female students from two British Universities participated. We found a significant two-way interaction on the imitation effect. When interacting in expectation of cooperation, imitation was stronger for an ingroup target compared to an outgroup target. However, this was not the case in the competitive condition where imitation did not differ between ingroup and outgroup target. This demonstrates that the goal structure of an expected interaction will determine the extent to which intergroup relations influence imitation, supporting a social identity approach.

  19. Supervision is also about Addressing the Group Dynamics

    DEFF Research Database (Denmark)

    Jensen, Lars Peter; Hansen, S.

    2003-01-01

    that many students are having difficulties with practical issues such as collaboration, communication, and project management. Most supervisors either ignore this demand, because they do not find it important or they find it frustrating, because they do not know, how to supervise group dynamics......An important aspect of the problem based and project organized study at Aalborg University is the supervision of the project groups. At the basic education (first year) it is stated in the curriculum that part of the supervisors' job is to deal with group dynamics. This is due to the experience...... as well as at Aalborg University. The first visible result has been participating supervisors telling us that the course has inspired them to try supervising group dynamics in the future. This paper will explore some aspects of supervising group dynamics as well as, how to develop the Aalborg model...

  20. Grouping of the design issues for KNGR MMI evaluation

    International Nuclear Information System (INIS)

    Oh, In Seok; Lee, Dong Young; Lee, Jung Woon; Lee, Hyn Chul; Park, Jae Chang

    2001-05-01

    The Korean Next Generation Reactor(KNGR) man-machine interface(MMI) design adopting digital technologies has been developed since 1997. The KNGR MMI consists of CRT-based operator workstations, large display panel(LDP), alarm System, soft control and computerized procedure system. Westinghouse tried to systematically identify and evaluate human factor potential issues of advanced control room. The KNGR MMI design features are very similar with those of the Westinghouse AP-600. The KNGR will try to reflect the evaluation results of 15 issues that the Westinghouse has developed. But it needs much time and costs to evaluate the 15 issues during this design phase. In this study, we analyzed evaluation issues of the AP-600 and classified the 13 issues, which the Westinghouse developed, into 5 groups to simultaneously except 2 issues which can not evaluate in this design phase

  1. Issues with performance measures for dynamic multi-objective optimisation

    CSIR Research Space (South Africa)

    Helbig, M

    2013-06-01

    Full Text Available Symposium on Computational Intelligence in Dynamic and Uncertain Environments (CIDUE), Mexico, 20-23 June 2013 Issues with Performance Measures for Dynamic Multi-objective Optimisation Mard´e Helbig CSIR: Meraka Institute Brummeria, South Africa...

  2. Dynamics of small groups of galaxies. I. Virialized groups

    International Nuclear Information System (INIS)

    Mamon, G.A.; New York Univ., NY)

    1987-01-01

    The dynamical evolution of small groups of galaxies from an initial virial equilibrium state is investigated by means of numerical simulations. The basic scheme is a gravitational N-body code in which galaxies and diffuse background are treated as single particles with both external parameters and internal structure; collisional and tidal stripping, dynamical friction, mergers, and orbital braking are taken into account. The results are presented in extensive tables and graphs and characterized in detail. Eight-galaxy groups with surface densities like those of compact groups (as defined by Hickson, 1982) are found to be unstable to rapid mergers after 1/30 to 1/8 Hubble time. The effects of dark-matter distribution (in galactic halos or in a common intergalactic background) are considered. 79 references

  3. Dynamic interaction effects in cooling tower groups

    International Nuclear Information System (INIS)

    Riera, J.D.

    1984-01-01

    A theoretical and experimental determination of the dynamic response of reinforced concrete cooling towers, taking into consideration group effects, are described. The results for an individual tower are thoroughly examined. A complete analysis is then performed for the critical wind orientations, for each tower in a six towers group. It's shown that ignoring group effects in the analysis may lead to a significant underestimation of the structural response. (E.G.) [pt

  4. Individual and group dynamics in purchasing activity

    Science.gov (United States)

    Gao, Lei; Guo, Jin-Li; Fan, Chao; Liu, Xue-Jiao

    2013-01-01

    As a major part of the daily operation in an enterprise, purchasing frequency is in constant change. Recent approaches on the human dynamics can provide some new insights into the economic behavior of companies in the supply chain. This paper captures the attributes of creation times of purchase orders to an individual vendor, as well as to all vendors, and further investigates whether they have some kind of dynamics by applying logarithmic binning to the construction of distribution plots. It’s found that the former displays a power-law distribution with approximate exponent 2.0, while the latter is fitted by a mixture distribution with both power-law and exponential characteristics. Obviously, two distinctive characteristics are presented for the interval time distribution from the perspective of individual dynamics and group dynamics. Actually, this mixing feature can be attributed to the fitting deviations as they are negligible for individual dynamics, but those of different vendors are cumulated and then lead to an exponential factor for group dynamics. To better describe the mechanism generating the heterogeneity of the purchase order assignment process from the objective company to all its vendors, a model driven by product life cycle is introduced, and then the analytical distribution and the simulation result are obtained, which are in good agreement with the empirical data.

  5. STATISTICAL TOOLS FOR CLASSIFYING GALAXY GROUP DYNAMICS

    International Nuclear Information System (INIS)

    Hou, Annie; Parker, Laura C.; Harris, William E.; Wilman, David J.

    2009-01-01

    The dynamical state of galaxy groups at intermediate redshifts can provide information about the growth of structure in the universe. We examine three goodness-of-fit tests, the Anderson-Darling (A-D), Kolmogorov, and χ 2 tests, in order to determine which statistical tool is best able to distinguish between groups that are relaxed and those that are dynamically complex. We perform Monte Carlo simulations of these three tests and show that the χ 2 test is profoundly unreliable for groups with fewer than 30 members. Power studies of the Kolmogorov and A-D tests are conducted to test their robustness for various sample sizes. We then apply these tests to a sample of the second Canadian Network for Observational Cosmology Redshift Survey (CNOC2) galaxy groups and find that the A-D test is far more reliable and powerful at detecting real departures from an underlying Gaussian distribution than the more commonly used χ 2 and Kolmogorov tests. We use this statistic to classify a sample of the CNOC2 groups and find that 34 of 106 groups are inconsistent with an underlying Gaussian velocity distribution, and thus do not appear relaxed. In addition, we compute velocity dispersion profiles (VDPs) for all groups with more than 20 members and compare the overall features of the Gaussian and non-Gaussian groups, finding that the VDPs of the non-Gaussian groups are distinct from those classified as Gaussian.

  6. Dynamical theory of dense groups of galaxies

    Science.gov (United States)

    Mamon, Gary A.

    1990-01-01

    It is well known that galaxies associate in groups and clusters. Perhaps 40% of all galaxies are found in groups of 4 to 20 galaxies (e.g., Tully 1987). Although most groups appear to be so loose that the galaxy interactions within them ought to be insignificant, the apparently densest groups, known as compact groups appear so dense when seen in projection onto the plane of the sky that their members often overlap. These groups thus appear as dense as the cores of rich clusters. The most popular catalog of compact groups, compiled by Hickson (1982), includes isolation among its selection critera. Therefore, in comparison with the cores of rich clusters, Hickson's compact groups (HCGs) appear to be the densest isolated regions in the Universe (in galaxies per unit volume), and thus provide in principle a clean laboratory for studying the competition of very strong gravitational interactions. The $64,000 question here is then: Are compact groups really bound systems as dense as they appear? If dense groups indeed exist, then one expects that each of the dynamical processes leading to the interaction of their member galaxies should be greatly enhanced. This leads us to the questions: How stable are dense groups? How do they form? And the related question, fascinating to any theorist: What dynamical processes predominate in dense groups of galaxies? If HCGs are not bound dense systems, but instead 1D change alignments (Mamon 1986, 1987; Walke & Mamon 1989) or 3D transient cores (Rose 1979) within larger looser systems of galaxies, then the relevant question is: How frequent are chance configurations within loose groups? Here, the author answers these last four questions after comparing in some detail the methods used and the results obtained in the different studies of dense groups.

  7. Dynamical interpretation of nonrelativistic conformal groups

    International Nuclear Information System (INIS)

    Andrzejewski, K.; Gonera, J.

    2013-01-01

    It is shown that N-Galilean conformal algebra with N odd and nontrivial central charge is the maximal symmetry algebra for higher derivative free theory both on classical and quantum levels. By maximal symmetry algebra the Lie algebra of the maximal group of space–time symmetry transformations is understood which preserves higher order free dynamics

  8. Introduction to Focus Issue: Time-delay dynamics

    Science.gov (United States)

    Erneux, Thomas; Javaloyes, Julien; Wolfrum, Matthias; Yanchuk, Serhiy

    2017-11-01

    The field of dynamical systems with time delay is an active research area that connects practically all scientific disciplines including mathematics, physics, engineering, biology, neuroscience, physiology, economics, and many others. This Focus Issue brings together contributions from both experimental and theoretical groups and emphasizes a large variety of applications. In particular, lasers and optoelectronic oscillators subject to time-delayed feedbacks have been explored by several authors for their specific dynamical output, but also because they are ideal test-beds for experimental studies of delay induced phenomena. Topics include the control of cavity solitons, as light spots in spatially extended systems, new devices for chaos communication or random number generation, higher order locking phenomena between delay and laser oscillation period, and systematic bifurcation studies of mode-locked laser systems. Moreover, two original theoretical approaches are explored for the so-called Low Frequency Fluctuations, a particular chaotical regime in laser output which has attracted a lot of interest for more than 30 years. Current hot problems such as the synchronization properties of networks of delay-coupled units, novel stabilization techniques, and the large delay limit of a delay differential equation are also addressed in this special issue. In addition, analytical and numerical tools for bifurcation problems with or without noise and two reviews on concrete questions are proposed. The first review deals with the rich dynamics of simple delay climate models for El Nino Southern Oscillations, and the second review concentrates on neuromorphic photonic circuits where optical elements are used to emulate spiking neurons. Finally, two interesting biological problems are considered in this Focus Issue, namely, multi-strain epidemic models and the interaction of glucose and insulin for more effective treatment.

  9. Complex dynamics in supervised work groups

    Science.gov (United States)

    Dal Forno, Arianna; Merlone, Ugo

    2013-07-01

    In supervised work groups many factors concur to determine productivity. Some of them may be economical and some psychological. According to the literature, the heterogeneity in terms of individual capacity seems to be one of the principal causes for chaotic dynamics in a work group. May sorting groups of people with same capacity for effort be a solution? In the organizational psychology literature an important factor is the engagement in the task, while expectations are central in the economics literature. Therefore, we propose a dynamical model which takes into account both engagement in the task and expectations. An important lesson emerges. The intolerance deriving from the exposure to inequity may not be only caused by differences in individual capacities, but also by these factors combined. Consequently, solutions have to be found in this new direction.

  10. Beam dynamic issues in TESLA damping ring

    International Nuclear Information System (INIS)

    Shiltsev, V.

    1996-05-01

    In this paper we study general requirements on impedances of the linear collider TESLA damping ring design. Quantitative consideration is performed for 17-km long ''dog-bone'' ring. Beam dynamics in alternative options of 6.3 and 2.3-km long damping rings is briefly discussed. 5 refs., 2 tabs

  11. Food Parenting Measurement Issues: Working Group Consensus Report

    OpenAIRE

    Hughes, Sheryl O.; Frankel, Leslie A.; Beltran, Alicia; Hodges, Eric; Hoerr, Sharon; Lumeng, Julie; Tovar, Alison; Kremers, Stef

    2013-01-01

    Childhood obesity is a growing problem. As more researchers become involved in the study of parenting influences on childhood obesity, there appears to be a lack of agreement regarding the most important parenting constructs of interest, definitions of those constructs, and measurement of those constructs in a consistent manner across studies. This article aims to summarize findings from a working group that convened specifically to discuss measurement issues related to parental influences on...

  12. Effect of social group dynamics on contagion

    Science.gov (United States)

    Zhao, Zhenyuan; Calderón, J. P.; Xu, Chen; Zhao, Guannan; Fenn, Dan; Sornette, Didier; Crane, Riley; Hui, Pak Ming; Johnson, Neil F.

    2010-05-01

    Despite the many works on contagion phenomena in both well-mixed systems and heterogeneous networks, there is still a lack of understanding of the intermediate regime where social group structures evolve on a similar time scale to individual-level transmission. We address this question by considering the process of transmission through a model population comprising social groups which follow simple dynamical rules for growth and breakup. Despite the simplicity of our model, the profiles produced bear a striking resemblance to a wide variety of real-world examples—in particular, empirical data that we have obtained for social (i.e., YouTube), financial (i.e., currency markets), and biological (i.e., colds in schools) systems. The observation of multiple resurgent peaks and abnormal decay times is qualitatively reproduced within the model simply by varying the time scales for group coalescence and fragmentation. We provide an approximate analytic treatment of the system and highlight a novel transition which arises as a result of the social group dynamics.

  13. Dynamic Incentives in Microfinance Group Lending

    Directory of Open Access Journals (Sweden)

    Naveen Kumar K

    2012-04-01

    Full Text Available One of the most essential tools of poverty reduction would be the viable expansion of institutional credit facilities to large sections of the people who neither have adequate collateral nor credit history to secure a loan. In this backdrop, social collateral is popularized through the group lending programs to address the credit market problems. Microfinance through group lending is acting as a screening device; the joint liability mechanism creates incentives for internal monitoring. Hence, it has received a lot of attention from policy makers as well as academicians. It is playing an important role in delivering financial services to the “socially and economically excluded” poor, in general, and women, in particular. The group lending works with various dynamic incentives. One such kind is principle of progressive lending and it plays a vital role in sustaining the groups for the persistent delivery of microfinance services to its members. In progressive lending, a typical borrower receives very small amounts at first, which increases with good repayment conduct or it links new, larger loans to past repayment. This article explores possible theoretical and empirical relationship between progressive lending and its determinants in group lending approach. The primary survey was conducted in 10 villages covering 106 self-help groups and 318 members in Karnataka, India. The empirical results show the progressive lending amount rising up to 698% of the initial loan of the self-help groups.

  14. Assessing Group Dynamics in a Mars Simulation

    Science.gov (United States)

    Bishop, S. L.

    2007-10-01

    International interest in psychosocial functioning generally and issues of group and inter-group function for space crews has increased as focus has shifted towards longer duration spaceflight and, particularly, the issues involved in sending a human crew to Mars (Kanas, et al., 2001; Dawson, 2002). Planning documents for a human mission to Mars such as the NASA Design Reference Mission (DRM 1.0) emphasize the need for adaptability of crewmembers and autonomy in the crew as a whole (Hoffman and Kaplan, 1997). Similarly a major study by the International Space University (ISU, 1991) emphasized the need for autonomy and initiative for a Mars crew given that many of the scenarios that will be encountered on Mars cannot be rehearsed on earth and given the lack of any realistic possibility for rescue of the crew. This research project was only one subset of data collected during the larger AustroMars Expedition at the Mars Desert Research Facility (MDRS) in 2006. The participating crew comprises part of a multi-year investigation on teams utilizing the MDRS facility. The program of research has included numerous researchers since 2002 with a progressive evolution of key foci addressing stress, personality, coping, adaptation, cognitive functioning, and group identity assessed across the duration period of the individual missions.

  15. Final report of the tritium issues working group. Vol. 1

    International Nuclear Information System (INIS)

    Spratt, Peter; Hardy, David; Peirce, Denny; Smith, Ron; Wyatt, Alan.

    1985-09-01

    Early in 1985 the proposed sale of the isotope 'tritium' by Ontario Hydro became a public issue. A number of community groups claimed in public forum that tritium recovered from Ontario Hydro's nuclear reactors would be sold or diverted to American thermonuclear (fusion) weapons. Their position was based on the following presumptions: that tritium was a major component in American nuclear weapons, that the United States has a supply problem with or shortage of this material, and that Ontario Hydro would directly or indirectly support the American nuclear weapons program: a) by providing tritium directly to the U.S. Department of Energy for use in nuclear weapons, or b) by supplying tritium to certain buyers - either traditional commercial facilities or the developing fusion research agencies associated with the Department of Energy, thus allowing or making possible the diversion of this isotope to nuclear weapons purposes, or c) by answering the needs of the commercial market, at present supplied from production reactors dedicated to supplying U.S. military requirements, indirectly allowing the U.S. government to concentrate its efforts on the production of tritium for nuclear weapons. When members of what has become known as the 'Tritium Issues Working Group' were first approached by Dr. T.S. Drolet in mid-April 1985, we were asked if we would agree to participate in a study to assess whether Canadian tritium, which is to be produced only for commercial and research purposes, could be inadvertantly utilized, either directly or indirectly, in the American nuclear weapons program. Our discussion of these issues is covered in Volume 1 of this report and is supplemented by appropriate Appendices in Volume 2. We could find absolutely nothing of a factual nature to justify the hypothesis that Canadian tritium would find its way into the American weapons program

  16. Treatment issues in the group psychotherapy of addicted physicians.

    Science.gov (United States)

    Fayne, M; Silvan, M

    1999-01-01

    For the most part, physician-addict patients are affable, cooperative and tend to be bright, verbal and engaging. However, on a deeper level they experience significant internal obstacles to truly using treatment. The role of the healer adopted after years of training and work experience is not easily exchanged for the role of patient. Furthermore, the armour of defenses and character style that have been built up over a lifetime is resistant to modification. Additionally, most of these patients have not chosen to change. They have been ordered into treatment under considerable duress and are aware that retaining their hard-earned careers is dependent on their successful performance in treatment. Given all these difficulties it is striking that the vast majority of these patients gradually come to experience a genuine and meaningful connection to the group and the therapeutic process. They develop close relationships with their fellow group members and come to use them as a support system, even at times when the group is not in session. They report looking forward to group and missing it when it does not meet. In this context they begin to take risks by sharing on a deeper level and slowly bring to the group issues in their life other than addiction. Their devotion to group is reflected by the fact that when no longer mandated, many continue voluntarily and maintain that the experience is central to their recovery. One of the major reasons recovering physicians are able to make this connection is that behind their fear of interpersonal relationships is a tremendous wish to join with others. Many report profound relief at discovering they are not alone and are able to use group to address their deeply felt sense of shame. For many this is their first experience of such strong feelings of attachment and affiliation to a group of peers. Their prior professional experience did not routinely allow for such relationships and as Smith (1978) has observed, their experience

  17. Food parenting measurement issues: working group consensus report.

    Science.gov (United States)

    Hughes, Sheryl O; Frankel, Leslie A; Beltran, Alicia; Hodges, Eric; Hoerr, Sharon; Lumeng, Julie; Tovar, Alison; Kremers, Stef

    2013-08-01

    Childhood obesity is a growing problem. As more researchers become involved in the study of parenting influences on childhood obesity, there appears to be a lack of agreement regarding the most important parenting constructs of interest, definitions of those constructs, and measurement of those constructs in a consistent manner across studies. This article aims to summarize findings from a working group that convened specifically to discuss measurement issues related to parental influences on childhood obesity. Six subgroups were formed to address key measurement issues. The conceptualization subgroup proposed to define and distinguish constructs of general parenting styles, feeding styles, and food parenting practices with the goal of understanding interrelating levels of parental influence on child eating behaviors. The observational subgroup identified the need to map constructs for use in coding direct observations and create observational measures that can capture the bidirectional effects of parent-child interactions. The self-regulation subgroup proposed an operational definition of child self-regulation of energy intake and suggested future measures of self-regulation across different stages of development. The translational/community involvement subgroup proposed the involvement of community in the development of surveys so that measures adequately reflect cultural understanding and practices of the community. The qualitative methods subgroup proposed qualitative methods as a way to better understand the breadth of food parenting practices and motivations for the use of such practices. The longitudinal subgroup stressed the importance of food parenting measures sensitive to change for use in longitudinal studies. In the creation of new measures, it is important to consider cultural sensitivity and context-specific food parenting domains. Moderating variables such as child temperament and child food preferences should be considered in models.

  18. Special Issue on Theoretical Chemistry/Chemical Dynamics

    Indian Academy of Sciences (India)

    2017-07-02

    Jul 2, 2017 ... This month's issue of the Journal of Chemical Sciences honours Professor Charusita Chakravarty, who has made immeasurable contributions to theoretical chemistry and chemical dynamics. The editors Biman Bagchi (FASc, FNA, FTWAS; Indian Institute of Science, Bangalore, India), David Clary (FRS; ...

  19. SURVEY ON SOLIDARITY GROUPS OF BUYERS: CRITICAL ISSUES

    Directory of Open Access Journals (Sweden)

    L. Pennisi

    2011-08-01

    Full Text Available This work is intended to provide, through the analysis of the dynamics of purchase of solidarity groups of buyers, a contribution to the study of current trends that are affecting the alternative to the dominant agro-food industry. Through the use of a questionnaire the paper investigated the perception as consumers this particular class of buyers have of themselves and how their concepts of “conscious choice” and “responsibility” drive their shopping list and consequently influence the growth and development of the Short Supply Chain, as the work remarked the progressive and notable increment of commerce and families circling around this young but widespreading phenomenon. Particularly striking, in fact, emerge from the role that consumers are becoming part of this phenomenon and the most of them have matured during time the idea that biological and hand-made products are for themselves also Safe, while the Long Supply Chain should incarnate the role of an alienating and wholly food system. The analysis of the questionnaires revealed some problems concerning the methods of transport and storage.

  20. Computational social dynamic modeling of group recruitment.

    Energy Technology Data Exchange (ETDEWEB)

    Berry, Nina M.; Lee, Marinna; Pickett, Marc; Turnley, Jessica Glicken (Sandia National Laboratories, Albuquerque, NM); Smrcka, Julianne D. (Sandia National Laboratories, Albuquerque, NM); Ko, Teresa H.; Moy, Timothy David (Sandia National Laboratories, Albuquerque, NM); Wu, Benjamin C.

    2004-01-01

    The Seldon software toolkit combines concepts from agent-based modeling and social science to create a computationally social dynamic model for group recruitment. The underlying recruitment model is based on a unique three-level hybrid agent-based architecture that contains simple agents (level one), abstract agents (level two), and cognitive agents (level three). This uniqueness of this architecture begins with abstract agents that permit the model to include social concepts (gang) or institutional concepts (school) into a typical software simulation environment. The future addition of cognitive agents to the recruitment model will provide a unique entity that does not exist in any agent-based modeling toolkits to date. We use social networks to provide an integrated mesh within and between the different levels. This Java based toolkit is used to analyze different social concepts based on initialization input from the user. The input alters a set of parameters used to influence the values associated with the simple agents, abstract agents, and the interactions (simple agent-simple agent or simple agent-abstract agent) between these entities. The results of phase-1 Seldon toolkit provide insight into how certain social concepts apply to different scenario development for inner city gang recruitment.

  1. An integrative framework for managing project issues across stakeholder groups

    NARCIS (Netherlands)

    van Offenbeek, Marjolein A.G.; Vos, Janita F.J.

    2016-01-01

    The stakeholders and the issues associated with a project are different concepts but closely interconnected. Despite this, the project stakeholder management literature falls short in analyzing the linkages between the stakeholders and the issues they bring. This paper develops a multilayered

  2. Final report of the tritium issues working group. Vol. 2

    International Nuclear Information System (INIS)

    Spratt, Peter; Hardy, David; Peirce, Denny; Smith, Ron; Wyatt, Alan.

    1985-09-01

    This report consists of a series of appendices relating to the sociological and technical considerations of tritium and its related technology. It is intended as a supplement to Volume 1 of the Final Report of the Tritium Issues Working Group. The work will the cover the following specific areas: A) Development of an ethical framework related to technology, morality, weapons, politics, etc. B) Review the history of nuclear power in Canada, placement of this technology in context with other technologies, waste products and the CANDU reactor system. C) Assessment of tritium as a unique product, as a class of isotopes, waste by-product and physical properties, effects on human life and its place in the natural environment. D) Assessment of tritium and the environment, diffusion through commerical application, European and American experience, waste management and recycling. E) Assessment of commercial applications, including current experience, historical applications for commercial purposes, offshore revenue for Canada value-added component and role of Ontario Hydro. F) Assessment of tritium and weapons, including technology and the military, past and future role of tritium in weapons, proliferation theories, generic conclusions regarding linkages, dependence of Americans on foreign sources of strategic resources. G) Review of regulations in effect now with respect to nuclear and/or other products with potential to military application, and what is needed. H) Review of traditional Canadian postures in the area of technology perception and political culture, the role, mandate and responsibility of Ontario Hydro, growth of international economy, Canada's competitive position in this economy and the challenges and dilemmas that modern decision makers have in a highly interrelated technological world

  3. Report of the working group on dynamics

    NARCIS (Netherlands)

    Casciati, F.; Grigoriu, M.; Kiureghian, A. der; Wen, Y.K.; Vrouwenvelder, T.

    1997-01-01

    This review article was especially prepared for possible use of code designers. Its purpose is to frame standard dynamics problems and algorithms within classical structural reliability schemes. © 1997 Elsevier Science Ltd.

  4. Beam dynamics issues of high-luminosity asymmetric collider rings

    International Nuclear Information System (INIS)

    Sessler, A.M.

    1990-01-01

    Machines for use in high-energy physics are advancing along two frontiers. First, there is the frontier of energy, currently being pressed by the Fermilab collider (p bar p), and SLC and LEP (e + e - ) and in the near future by HERA (ep), the LHC, and the SSC (pp). Second, there is the frontier of intensity, currently being pressed by a variety of low-energy machines and, at higher energies, by various linacs such as those at KEK. Fermilab, GSI, and LAMPF (p) and CEBAF (e - ). In the future there should be, along this frontier, various ''factories'' such as those for Kaons at TRIUMF, and those proposed for var-phi mesons, τ-charm particles, and B mesons. It is with the intensity frontier that these proceedings are concerned. The elementary particle motivation to study the nonconservation of PC in the B-stringB system (which topic is not covered in these Proceedings, but is treated extensively in the literature) has motivated the study of very high intensity asymmetric collider rings. It was for this purpose that a Workshop on Beam Dynamics Issues of High-Luminosity Asymmetric Collider Rings was held, in Berkeley, during February 12--16, 1990. A general introduction to the subject has been given in an article which is reprinted here as an Appendix. The nonexpert may wish to start there. The volume consists of four parts. The first part consists of Summaries; first an overall summary of the Workshop and then, second, more detailed summaries from each of the working groups. The second part consists of the Invited Talks at the workshop. The third part contains various Contributed Papers, most of which represent work that came out of the workshop. Finally, there are, in the fourth part, brief Summaries of the Various Proposed B-Factory Projects in the world

  5. A Dynamic Policy for Grouping Maintenance Activities

    NARCIS (Netherlands)

    R.E. Wildeman (Ralph); R. Dekker (Rommert); A.C.J.M. Smit

    1995-01-01

    textabstractA maintenance activity carried out on a technical system often involves a system-dependent set-up cost that is the same for all maintenance activities carried out on that system. Grouping activities thus saves costs since execution of a group of activities requires only one set-up. Many

  6. Regional disarmament and security issues. Report of working group II

    International Nuclear Information System (INIS)

    Ravenhill, J.

    1994-01-01

    Substantial progress has been made in building cooperation in the Asia-pacific region in remarkably short period of time. Problems of regional disarmament are analysed by linking the economic and security issues. International cooperation regimes, whether in the military sphere, such as the Non-proliferation treaty, or in the trade sphere such as the General Agreement on Tariffs and Trade, inevitably impose restrictions on the autonomy of member States. The integrity of the regime depends on countries' acceptance of the obligations it imposes. The task ahead is to convince all countries in the region that cooperation in the security sphere will be of even greater long-term benefit

  7. Total Quality Management (TQM): Group Dynamics Workshop

    Science.gov (United States)

    1990-05-15

    take for these changes to penetrate most OSD agencies. - The unique organizational culture, structure, and functioning of OSD (i.e., a gigantic size...Performing (group problem solving; Performing diagnosing and solving quality problems and sele2cting and implementing solutions). Total Quality Management...Stage, the quality improvement group diagnoses the quality problem/opportunity, gathers the right kind of quantitative data, and formulates, selects, and

  8. Kibel groups and their dynamic perspective

    DEFF Research Database (Denmark)

    Heinskou, Torben

    2010-01-01

    the uncontainable: A role for staff support groups. Ian Simpson Groupwork: The evidence base. Chris Evans et al The working alliance in groupwork on acute psychiatric wards. Oded Manor Part 2: Specific Therapeutic Applications Specific Therapeutic Applications. Inpatient group therapy based on the Yalom...... on acute inpatient wards. Oded Manor is a leading authority in groupwork, previously Principal Lecturer in Social Work at Middlesex University...

  9. Dynamical properties of compact groups of galaxies

    Science.gov (United States)

    Hickson, Paul; De Oliveira, Claudia M.; Huchra, John P.; Palumbo, Giorgio G.

    1992-01-01

    Radial velocities are presented for 457 galaxies in the 100 Hickson compact groups. More than 84 percent of the galaxies measured have velocities within 1000 km/s of the median velocity in the group. Ninety-two groups have at least three accordant members, and 69 groups have at least four. The radial velocities of these groups range from 1380 to 42,731 km/s with a median of 8889 km/s, corresponding to a median distance of 89/h Mpc. The apparent space density of these systems ranges from 300 to as much as 10 exp 8 sq h/sq Mpc, which exceeds the densities in the centers of rich clusters. The median projected separation between galaxies is 39/h kpc, comparable to the sizes of the galaxies themselves. A significant correlation is found between crossing time and the fraction of gas-rich galaxies in the groups, and a weak anticorrelation is found between crossing time and the luminosity contrast of the first-ranked galaxy.

  10. Information behavior in dynamic group work contexts

    DEFF Research Database (Denmark)

    Sonnenwald, Diane H.; Pierce, Linda G.

    2000-01-01

    personnel and documentation on C2. During data analysis, three important themes that highlight the why, what, how and consequences of information behavior in C2 emerged. The first is the concept of interwoven situational awareness consisting of individual, intragroup and intergroup shared understanding...... of the situation. Interwoven situational awareness appears to facilitate response to dynamic, constraint-bound situations. The second theme describes the need for dense social networks or frequent communication between participants about the work context and situation, the work process and domain...

  11. Kibel groups and their dynamic perspective

    DEFF Research Database (Denmark)

    Heinskou, Torben

    2010-01-01

    authors look the state of research on therapeutic groupwork in inpatient settings, and suggest how the evidence base might be strengthened. The book will be of great value to any mental health professional, whether qualified or in training. Although reflecting experience in British clinical settings...... Interpersonal Model. Katja Hajek The groupworker as consultant to the group. Adam Jefford, Bhupinderjit Kaur Pharwaha and Alistair Grandison Running structured problem solving groups on acute wards. Susan J. Grey Psychodynamically informed groupwork with patients with psychosis:Challenges for co...

  12. Rapid Prototyping of Social Group Dynamics in Multiagent Systems

    DEFF Research Database (Denmark)

    Rehm, Matthias; Endrass, Birgit

    2009-01-01

    In this article we present an engineering approach for the integration of social group dynamics in the behavior modeling of multiagent systems. To this end, a toolbox was created that brings together several theories from the social sciences, each focusing on different aspects of group dynamics. ...

  13. Some Practical Issues in the Design and Implementation of Group Communication Services

    National Research Council Canada - National Science Library

    Mishra, Shivakant

    2000-01-01

    The main objective of the proposed research was to investigate four important practical issues in the understanding, design, and implementation of group communication services. These issues were (1) Performance...

  14. Exploring Challenging Group Dynamics in Participatory Design with Children

    OpenAIRE

    Van Mechelen, Maarten; Gielen, Matthieu; Vanden Abeele, Vero; Laenen, Ann; Zaman, Bieke

    2014-01-01

    This paper presents a structured way to evaluate challenging group or 'codesign dynamics' in participatory design processes with children. In the form of a critical reflection on a project in which 103 children were involved as design partners, we describe the most prevalent codesign dynamics. For example, some groups rush too quickly towards consensus to safeguard group cohesiveness instead of examining other choice alternatives (i.e., groupthink). Besides 'groupthink' we describe five more ...

  15. Empirical study on social groups in pedestrian evacuation dynamics

    Science.gov (United States)

    von Krüchten, Cornelia; Schadschneider, Andreas

    2017-06-01

    Pedestrian crowds often include social groups, i.e. pedestrians that walk together because of social relationships. They show characteristic configurations and influence the dynamics of the entire crowd. In order to investigate the impact of social groups on evacuations we performed an empirical study with pupils. Several evacuation runs with groups of different sizes and different interactions were performed. New group parameters are introduced which allow to describe the dynamics of the groups and the configuration of the group members quantitatively. The analysis shows a possible decrease of evacuation times for large groups due to self-ordering effects. Social groups can be approximated as ellipses that orientate along their direction of motion. Furthermore, explicitly cooperative behaviour among group members leads to a stronger aggregation of group members and an intermittent way of evacuation.

  16. GROUP DYNAMICS AND TEAM FUNCTIONING IN ORGANIZATIONAL CONTEXT

    Directory of Open Access Journals (Sweden)

    Raluca ZOLTAN

    2015-07-01

    Full Text Available In all kind of organization many activities are done by groups and teams. But how are they formed? What factors influence their existence and development? How members of groups and teams are selected? Which are the consequences in organizational context? In order to answer these questions, in the present paper we describe and analyze the main approaches regarding the formation of work groups and work teams (sociometric approach and group dynamics approach, the main factors that affects group dynamics and the FIRO model for evaluation the team members’ needs.

  17. New Frontiers in Analyzing Dynamic Group Interactions: Bridging Social and Computer Science.

    Science.gov (United States)

    Lehmann-Willenbrock, Nale; Hung, Hayley; Keyton, Joann

    2017-10-01

    This special issue on advancing interdisciplinary collaboration between computer scientists and social scientists documents the joint results of the international Lorentz workshop, "Interdisciplinary Insights into Group and Team Dynamics," which took place in Leiden, The Netherlands, July 2016. An equal number of scholars from social and computer science participated in the workshop and contributed to the papers included in this special issue. In this introduction, we first identify interaction dynamics as the core of group and team models and review how scholars in social and computer science have typically approached behavioral interactions in groups and teams. Next, we identify key challenges for interdisciplinary collaboration between social and computer scientists, and we provide an overview of the different articles in this special issue aimed at addressing these challenges.

  18. Spontaneous formation of dynamical groups in an adaptive networked system

    International Nuclear Information System (INIS)

    Li Menghui; Guan Shuguang; Lai, C-H

    2010-01-01

    In this work, we investigate a model of an adaptive networked dynamical system, where the coupling strengths among phase oscillators coevolve with the phase states. It is shown that in this model the oscillators can spontaneously differentiate into two dynamical groups after a long time evolution. Within each group, the oscillators have similar phases, while oscillators in different groups have approximately opposite phases. The network gradually converts from the initial random structure with a uniform distribution of connection strengths into a modular structure that is characterized by strong intra-connections and weak inter-connections. Furthermore, the connection strengths follow a power-law distribution, which is a natural consequence of the coevolution of the network and the dynamics. Interestingly, it is found that if the inter-connections are weaker than a certain threshold, the two dynamical groups will almost decouple and evolve independently. These results are helpful in further understanding the empirical observations in many social and biological networks.

  19. Using Focus Groups to Research Sensitive Issues: Insights from Group Interviews on Nursing in the Northern Ireland “Troubles”

    Directory of Open Access Journals (Sweden)

    Joanne Jordan

    2007-12-01

    Full Text Available In this article the authors discuss the usefulness of focus groups for researching sensitive issues using evidence from a study examining the experiences of nurses providing care in the context of the Northern Ireland Troubles. They conducted three group interviews with nurses during which they asked about the issues the nurses face(d in providing nursing care amid enduring social division. Through a discursive analysis of within-group interaction, they demonstrate how participants employ a range of interpretive resources, the effect of which is to prioritize particular knowledge concerning the nature of nursing care. The identification of such patterned activity highlights the ethnographic value of focus groups to reveal social conventions guiding the production of accounts but also suggests that accounts cannot be divorced from the circumstances of their production. Consequently, the authors argue that focus groups should be considered most useful for illuminating locally sanctioned ways of talking about sensitive issues.

  20. New Frontiers in Analyzing Dynamic Group Interactions : Bridging Social and Computer Science

    NARCIS (Netherlands)

    Lehmann-Willenbrock, Nale; Hung, H.S.; Keyton, Joann

    2017-01-01

    This special issue on advancing interdisciplinary collaboration between computer scientists and social scientists documents the joint results of the international Lorentz workshop, “Interdisciplinary Insights into Group and Team Dynamics,” which took place in Leiden, The Netherlands, July 2016.

  1. Multi-group dynamic quantum secret sharing with single photons

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hongwei [School of Science and State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Ma, Haiqiang, E-mail: hqma@bupt.edu.cn [School of Science and State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Wei, Kejin [School of Science and State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Yang, Xiuqing [School of Science, Beijing Jiaotong University, Beijing 100044 (China); Qu, Wenxiu; Dou, Tianqi; Chen, Yitian; Li, Ruixue; Zhu, Wu [School of Science and State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China)

    2016-07-15

    In this letter, we propose a novel scheme for the realization of single-photon dynamic quantum secret sharing between a boss and three dynamic agent groups. In our system, the boss can not only choose one of these three groups to share the secret with, but also can share two sets of independent keys with two groups without redistribution. Furthermore, the security of communication is enhanced by using a control mode. Compared with previous schemes, our scheme is more flexible and will contribute to a practical application. - Highlights: • A multi-group dynamic quantum secret sharing with single photons scheme is proposed. • Any one of the groups can be chosen to share secret through controlling the polarization of photons. • Two sets of keys can be shared simultaneously without redistribution.

  2. Opinion dynamics within a virtual small group: the stubbornness effect

    Science.gov (United States)

    Guazzini, Andrea; Cini, Alessandro; Bagnoli, Franco; Ramasco, José

    2015-09-01

    The modeling of opinion dynamics is social systems has attracted a good deal of attention in the last decade. Even though based on intuition and observation, the mechanisms behind many of these models need solid empirical grounding. In this work, we investigate the relation among subjective variables (such as the personality), the dynamics of the affinity network dynamics, the communication patterns emerging throughout the social interactions and the opinions dynamics in a series of experiments with five small groups of ten people each. In order to ignite the discussion, the polemic topic of animal experimentation was proposed. The groups essentially polarized in two factions with a set of stubborn individuals (those not changing their opinions in time) playing the role of anchors. Our results suggest that the different layers present in the group dynamics (i.e., individual level, group dynamics and meso-communication) are deeply intermingled, specifically the stubbornness effect appears to be related to the dynamical features of the network topologies, and only in an undirected way to the personality of the participants.

  3. Opinion dynamics within a virtual small group: the stubbornness effect

    Directory of Open Access Journals (Sweden)

    Andrea eGuazzini

    2015-09-01

    Full Text Available The modeling of opinion dynamics is social systems has attracted a good deal of attention in the last decade. Even though based on intuition and observation, the mechanisms behind many of these models need solid empirical grounding. In this work, we investigate the relation among subjective variables (such as the personality, the dynamics of the affinity network dynamics, the communication patterns emerging throughout the social interactions and the opinions dynamics in a series of experiments with five small groups of ten people each. In order to ignite the discussion, the polemic topic of animal experimentation was proposed. The groups essentially polarized in two factions with a set of stubborn individuals (those not changing their opinions in time playing the role of anchors. Our results suggest that the different layers present in the group dynamics (i.e., individual level, group dynamics and meso-communication are deeply intermingled, specifically the stubbornness effect appears to be related to the dynamical features of the network topologies, and only in an undirected way to the personality of the participants.

  4. Nonlinear dynamics in the perceptual grouping of connected surfaces.

    Science.gov (United States)

    Hock, Howard S; Schöner, Gregor

    2016-09-01

    Evidence obtained using the dynamic grouping method has shown that the grouping of an object's connected surfaces has properties characteristic of a nonlinear dynamical system. When a surface's luminance changes, one of its boundaries is perceived moving across the surface. The direction of this dynamic grouping (DG) motion indicates which of two flanking surfaces has been grouped with the changing surface. A quantitative measure of overall grouping strength (affinity) for adjacent surfaces is provided by the frequency of DG motion perception in directions promoted by the grouping variables. It was found that: (1) variables affecting surface grouping for three-surface objects evolve over time, settling at stable levels within a single fixation, (2) how often DG motion is perceived when a surface's luminance is perturbed (changed) depends on the pre-perturbation affinity state of the surface grouping, (3) grouping variables promoting the same surface grouping combine cooperatively and nonlinearly (super-additively) in determining the surface grouping's affinity, (4) different DG motion directions during different trials indicate that surface grouping can be bistable, which implies that inhibitory interactions have stabilized one of two alternative surface groupings, and (5) when alternative surface groupings have identical affinity, stochastic fluctuations can break the symmetry and inhibitory interactions can then stabilize one of the surface groupings, providing affinity levels are not too high (which results in bidirectional DG motion). A surface-grouping network is proposed within which boundaries vary in salience. Low salience or suppressed boundaries instantiate surface grouping, and DG motion results from changes in boundary salience. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Metastable structures and size effects in small group dynamics.

    Science.gov (United States)

    Lauro Grotto, Rosapia; Guazzini, Andrea; Bagnoli, Franco

    2014-01-01

    In his seminal works on group dynamics Bion defined a specific therapeutic setting allowing psychoanalytic observations on group phenomena. In describing the setting he proposed that the group was where his voice arrived. This physical limit was later made operative by assuming that the natural dimension of a therapeutic group is around 12 people. Bion introduced a theory of the group aspects of the mind in which proto-mental individual states spontaneously evolve into shared psychological states that are characterized by a series of features: (1) they emerge as a consequence of the natural tendency of (both conscious and unconscious) emotions to combine into structured group patterns; (2) they have a certain degree of stability in time; (3) they tend to alternate so that the dissolution of one is rapidly followed by the emergence of another; (4) they can be described in qualitative terms according to the nature of the emotional mix that dominates the state, in structural terms by a kind of typical "leadership" pattern, and in "cognitive" terms by a set of implicit expectations that are helpful in explaining the group behavior (i.e., the group behaves "as if" it was assuming that). Here we adopt a formal approach derived from Socio-physics in order to explore some of the structural and dynamic properties of this small group dynamics. We will described data from an analytic DS model simulating small group interactions of agents endowed with a very simplified emotional and cognitive dynamic in order to assess the following main points: (1) are metastable collective states allowed to emerge in the model and if so, under which conditions in the parameter space? (2) can these states be differentiated in structural terms? (3) to what extent are the emergent dynamic features of the systems dependent of the system size? We will finally discuss possible future applications of the quantitative descriptions of the interaction structure in the small group clinical setting.

  6. Metastable structures and size effects in small group dynamics

    Directory of Open Access Journals (Sweden)

    Rosapia eLauro Grotto

    2014-07-01

    Full Text Available In his seminal works on group dynamics Bion defined a specific therapeutic setting allowing psychoanalytic observations on group phenomena. In describing the setting he proposed that the group was where his voice arrived. This physical limit was later made operative by assuming that the natural dimension of a therapeutic group is around 12 people. Bion introduced a theory of the group aspects of the mind in which proto-mental individual states spontaneously evolve into shared psychological states that are characterized by a series of features: 1 they emerge as a consequence of the natural tendency of (both conscious and unconscious emotions to combine into structured group patterns; 2 they have a certain degree of stability in time; 3 they tend to alternate so that the dissolution of one is rapidly followed by the emergence of another; 4 they can be described in qualitative terms according to the nature of the emotional mix that dominates the state, in structural terms by a kind of typical 'leadership’ pattern, and in 'cognitive’ terms by a set of implicit expectations that are helpful in explaining the group behavior (i.e. the group behaves 'as if’ it was assuming that…. Here we adopt a formal approach derived from Socio-physics in order to explore some of the structural and dynamic properties of this small group dynamics. We will described data from an analytic DS model simulating small group interactions of agents endowed with a very simplified emotional and cognitive dynamic in order to assess the following main points: 1 are metastable collective states allowed to emerge in the model and if so, under which conditions in the parameter space? 3 can these states be differentiated in structural terms? 3 to what extent are the emergent dynamic features of the systems dependent of the system size? We will finally discuss possible future applications of the quantitative descriptions of the interaction structure in the small group clinical

  7. Training Vocational Rehabilitation Counselors in Group Dynamics: A Psychoeducational Model.

    Science.gov (United States)

    Elliott, Timothy R.

    1990-01-01

    Describes a six-session psychoeducational program for training vocational rehabilitation counselors in group dynamics. Presents evaluation of program by counselors (N=15) in which leadership styles, conflict management, and typology of group tasks concepts were rated as most beneficial. (Author/ABL)

  8. Group Dynamics in the Interior Design Studio: Student Perceptions

    Science.gov (United States)

    Hill, Caroline

    2008-01-01

    This article presents the findings of a study measuring the classroom climates in collegiate interior design studios and considers these findings within the group dynamics theory framework. Three groups of students completed the College Classroom Environment Scales (CCES) questionnaire. Five of the six CCES subscale F ratios were statistically…

  9. Group dynamics challenges: Insights from Biosphere 2 experiments

    Science.gov (United States)

    Nelson, Mark; Gray, Kathelin; Allen, John P.

    2015-07-01

    Successfully managing group dynamics of small, physically isolated groups is vital for long duration space exploration/habitation and for terrestrial CELSS (Controlled Environmental Life Support System) facilities with human participants. Biosphere 2 had important differences and shares some key commonalities with both Antarctic and space environments. There were a multitude of stress factors during the first two year closure experiment as well as mitigating factors. A helpful tool used at Biosphere 2 was the work of W.R. Bion who identified two competing modalities of behavior in small groups. Task-oriented groups are governed by conscious acceptance of goals, reality-thinking in relation to time and resources, and intelligent management of challenges. The opposing unconscious mode, the "basic-assumption" ("group animal") group, manifests through Dependency/Kill the Leader, Fight/Flight and Pairing. These unconscious dynamics undermine and can defeat the task group's goal. The biospherians experienced some dynamics seen in other isolated teams: factions developing reflecting personal chemistry and disagreements on overall mission procedures. These conflicts were exacerbated by external power struggles which enlisted support of those inside. Nevertheless, the crew evolved a coherent, creative life style to deal with some of the deprivations of isolation. The experience of the first two year closure of Biosphere 2 vividly illustrates both vicissitudes and management of group dynamics. The crew overrode inevitable frictions to creatively manage both operational and research demands and opportunities of the facility, thus staying 'on task' in Bion's group dynamics terminology. The understanding that Biosphere 2 was their life support system may also have helped the mission to succeed. Insights from the Biosphere 2 experience can help space and remote missions cope successfully with the inherent challenges of small, isolated crews.

  10. Group dynamics challenges: Insights from Biosphere 2 experiments.

    Science.gov (United States)

    Nelson, Mark; Gray, Kathelin; Allen, John P

    2015-07-01

    Successfully managing group dynamics of small, physically isolated groups is vital for long duration space exploration/habitation and for terrestrial CELSS (Controlled Environmental Life Support System) facilities with human participants. Biosphere 2 had important differences and shares some key commonalities with both Antarctic and space environments. There were a multitude of stress factors during the first two year closure experiment as well as mitigating factors. A helpful tool used at Biosphere 2 was the work of W.R. Bion who identified two competing modalities of behavior in small groups. Task-oriented groups are governed by conscious acceptance of goals, reality-thinking in relation to time and resources, and intelligent management of challenges. The opposing unconscious mode, the "basic-assumption" ("group animal") group, manifests through Dependency/Kill the Leader, Fight/Flight and Pairing. These unconscious dynamics undermine and can defeat the task group's goal. The biospherians experienced some dynamics seen in other isolated teams: factions developing reflecting personal chemistry and disagreements on overall mission procedures. These conflicts were exacerbated by external power struggles which enlisted support of those inside. Nevertheless, the crew evolved a coherent, creative life style to deal with some of the deprivations of isolation. The experience of the first two year closure of Biosphere 2 vividly illustrates both vicissitudes and management of group dynamics. The crew overrode inevitable frictions to creatively manage both operational and research demands and opportunities of the facility, thus staying 'on task' in Bion's group dynamics terminology. The understanding that Biosphere 2 was their life support system may also have helped the mission to succeed. Insights from the Biosphere 2 experience can help space and remote missions cope successfully with the inherent challenges of small, isolated crews. Copyright © 2015 The Committee on

  11. What an understanding of the dynamics of gossip has to teach about group dynamics and group leadership.

    Science.gov (United States)

    Gans, Jerome S

    2014-01-01

    Although what transpires in group therapy is not gossip per se-except perhaps when absent or former members are discussed-listening to group interaction through an understanding of the dynamics of gossip can contribute to a greater appreciation of group dynamics and group leadership as well as enlarge therapeutic space. After examining the interpersonal dynamics of gossip, this paper discusses six ways in which an understanding of these dynamics can inform group leadership and shed light on group psychotherapy. Central features of gossip that appear in group interactions are explored: These include projection, displacement, self-esteem regulation, clarification of motivation, unself-consciousness, social comparison and bonding, avoidance of psychic pain, and making the ego-syntonic dystonic. The lively use of imagination in the mature phase of group therapy is conceived of as the time when the darker side of human nature-imagined gossip harnessed for therapeutic purposes-can be welcomed in and processed in a kind, playful, and compassionate manner.

  12. Issues in the Analysis of Focus Groups: Generalisability, Quantifiability, Treatment of Context and Quotations

    Science.gov (United States)

    Vicsek, Lilla

    2010-01-01

    In this paper I discuss some concerns related to the analysis of focus groups: (a) the issue of generalisation; (b) the problems of using numbers and quantifying in the analysis; (c) how the concrete situation of the focus groups could be included in the analysis, and (d) what formats can be used when quoting from focus groups. Problems with…

  13. Qualitative methods in nuclear reactor dynamics. Issue 23

    International Nuclear Information System (INIS)

    Goryachenko, V.D.

    1983-01-01

    Applicability of qualitative methods of the theory of nonlinear oscillations including the bifurcation theory to the problems of nuclear reactor nonlinear dynamics is investigated. Basic statements of the dynamic system qualitative theory on a phase plane and the bifurcation theory of multidimensional dynamic systems are briefly outlined. The model of reactor dynamics with two reactivity temperature coefficients neglecting delayed neutrons, the model of slow process dynamics in a reactor with two reactivity temperature coefficients, the simplified model of reactor dynamics as an object with delay and the model of a reactor with linear feedback are considered. A conclusion is drawn that the usage of the above models allows one to reveal qualitative peculiarities of reactor dynamics creating conditions for more purposeful utilization of more complicated models

  14. New insights in particle dynamics from group cohomology

    International Nuclear Information System (INIS)

    Aldaya, V; Jaramillo, J L; Guerrero, J

    2002-01-01

    The dynamics of a particle moving in background electromagnetic and gravitational fields is revisited from a Lie group cohomological perspective. Physical constants characterizing the particle appear as central extension parameters of a group which is obtained from a centrally extended kinematical group (Poincare or Galilei) by making some subgroup local. The corresponding dynamics is generated by a vector field inside the kernel of a pre-symplectic form which is derived from the canonical left-invariant 1-form on the extended group. A non-relativistic limit is derived from the geodesic motion via an Inoenue-Wigner contraction. A deeper analysis of the cohomological structure reveals the possibility of a new force associated with a non-trivial mixing of gravity and electromagnetism leading to, in principle, testable predictions. (letter to the editor)

  15. Relativized problems with abelian phase group in topological dynamics.

    Science.gov (United States)

    McMahon, D

    1976-04-01

    Let (X, T) be the equicontinuous minimal transformation group with X = pi(infinity)Z(2), the Cantor group, and S = [unk](infinity)Z(2) endowed with the discrete topology acting on X by right multiplication. For any countable group T we construct a function F:X x S --> T such that if (Y, T) is a minimal transformation group, then (X x Y, S) is a minimal transformation group with the action defined by (x, y)s = [xs, yF(x, s)]. If (W, T) is a minimal transformation group and varphi:(Y, T) --> (W, T) is a homomorphism, then identity x varphi:(X x Y, S) --> (X x W, S) is a homomorphism and has many of the same properties that varphi has. For this reason, one may assume that the phase group is abelian (or S) without loss of generality for many relativized problems in topological dynamics.

  16. Dynamics on the group manifolds and path integral

    International Nuclear Information System (INIS)

    Marinov, M.S.; Terentyev, M.V.

    1979-01-01

    Classical and quantum dynamics onn the compact simple Lie group and on the sphere of arbitrary dimensionality are considered. The accuracy of the semiclassical approximation for Green functions is discussed. Various path integral representations of the Green functions are presented. The special features of these representations due to the compactness and curvature are analysed. Basic results of the theory of Lie algebras and Lie groups used in the main text are presented

  17. Bottlenose dolphin Tursiops truncatus group dynamics, site fidelity ...

    African Journals Online (AJOL)

    ... ecology in these waters. Photo-identification undertaken during systematic, non-systematic and opportunistic surveys conducted between 2001 and 2012 was used to assess group dynamics, site fidelity, residency and movement patterns of bottlenose dolphins in the archipelago. Three different patterns of residency were ...

  18. The dynamics of access to groups in working memory.

    Science.gov (United States)

    Farrell, Simon; Lelièvre, Anna

    2012-11-01

    The finding that participants leave a pause between groups when attempting serial recall of temporally grouped lists has been taken to indicate access to a hierarchical representation of the list in working memory. An alternative explanation is that the dynamics of serial recall solely reflect output (rather than memorial) processes, with the temporal pattern at input merely suggesting a basis for the pattern of output buffering. Three experiments are presented here that disentangle input structure from output buffering in serial recall. In Experiment 1, participants were asked to recall a subset of visually presented digits from a temporally grouped list in their original order, where either within-group position or group position was kept constant. In Experiment 2, participants performed more standard serial recall of spoken digits, and input and output position were dissociated by asking participants to initiate recall from a post-cued position in the list. In Experiment 3, participants were asked to serially recall temporally grouped lists of visually presented digits where the grouping structure was unpredictable, under either articulatory suppression or silent conditions. The 3 experiments point to a tight linkage between implied memorial structures (i.e., the pattern of grouping at encoding) and the output structure implied by retrieval times and call into question a purely motoric account of the dynamics of recall.

  19. Dynamics of group knowledge production in facilitated modelling workshops

    DEFF Research Database (Denmark)

    Tavella, Elena; Franco, L. Alberto

    2015-01-01

    by which models are jointly developed with group members interacting face-to-face, with or without computer support. The models produced are used to inform negotiations about the nature of the issues faced by the group, and how to address them. While the facilitated modelling literature is impressive......, the workshop. Drawing on the knowledge-perspective of group communication, we conducted a micro-level analysis of a transcript of a facilitated modelling workshop held with the management team of an Alternative Food Network in the UK. Our analysis suggests that facilitated modelling interactions can take...

  20. Emergence of grouping in multi-resource minority game dynamics

    Science.gov (United States)

    Huang, Zi-Gang; Zhang, Ji-Qiang; Dong, Jia-Qi; Huang, Liang; Lai, Ying-Cheng

    2012-10-01

    Complex systems arising in a modern society typically have many resources and strategies available for their dynamical evolutions. To explore quantitatively the behaviors of such systems, we propose a class of models to investigate Minority Game (MG) dynamics with multiple strategies. In particular, agents tend to choose the least used strategies based on available local information. A striking finding is the emergence of grouping states defined in terms of distinct strategies. We develop an analytic theory based on the mean-field framework to understand the ``bifurcations'' of the grouping states. The grouping phenomenon has also been identified in the Shanghai Stock-Market system, and we discuss its prevalence in other real-world systems. Our work demonstrates that complex systems obeying the MG rules can spontaneously self-organize themselves into certain divided states, and our model represents a basic and general mathematical framework to address this kind of phenomena in social, economical and political systems.

  1. Dynamical evolution of clusters with two stellar groups

    Energy Technology Data Exchange (ETDEWEB)

    Angeletti, L; Giannone, P. (Rome Univ. (Italy))

    1977-08-01

    The generalization of the fluid-dynamical approach from one-component star clusters to clusters with several stellar groups (as far as the star masses are concerned) has been applied to the study of two-component clusters. Rather extreme values of stellar masses and masses of groups were chosen in order to emphasize the different dynamical evolutions and asymptotic behaviors. Escape of stars from clusters and the problem of equipartition of kinetic energy among the two star groups are discussed. Comparisons of the main features of the results with those obtained by other authors have shown a good agreement. Some characteristic properties of the last computed models with an age of 18x10/sup 9/ yr have been pointed out and discussed in relation with some observed features of galactic globular clusters.

  2. Action research in gender issues in science education: Towards an understanding of group work with science teachers

    Science.gov (United States)

    Nyhof-Young, Joyce Marion

    groups through a critical examination of the group dynamics and power issues arising within our group. The results of this study challenge us as educators to clarify our visions, to share power, to negotiate and to collaborate across our differences.

  3. Issues in Feminist Therapy: The Work of a Women's Study Group

    Science.gov (United States)

    Radov, Carol G.; And Others

    1977-01-01

    Discusses attempts of study groups of women in mental health professions that was instrumental in developing thearetical formulations concerning feminist therapy. From experiences both in the group and with clients, concludes that the profession as a whole must increase its responsiveness to concerns of women and issues of feminist therapy.…

  4. PWL approximation of nonlinear dynamical systems, part II: identification issues

    International Nuclear Information System (INIS)

    De Feo, O; Storace, M

    2005-01-01

    This paper and its companion address the problem of the approximation/identification of nonlinear dynamical systems depending on parameters, with a view to their circuit implementation. The proposed method is based on a piecewise-linear approximation technique. In particular, this paper describes a black-box identification method based on state space reconstruction and PWL approximation, and applies it to some particularly significant dynamical systems (two topological normal forms and the Colpitts oscillator)

  5. Modelling animal group fission using social network dynamics.

    Directory of Open Access Journals (Sweden)

    Cédric Sueur

    Full Text Available Group life involves both advantages and disadvantages, meaning that individuals have to compromise between their nutritional needs and their social links. When a compromise is impossible, the group splits in order to reduce conflict of interests and favour positive social interactions between its members. In this study we built a dynamic model of social networks to represent a succession of temporary fissions involving a change in social relations that could potentially lead to irreversible group fission (i.e. no more group fusion. This is the first study that assesses how a social network changes according to group fission-fusion dynamics. We built a model that was based on different parameters: the group size, the influence of nutritional needs compared to social needs, and the changes in the social network after a temporary fission. The results obtained from this theoretical data indicate how the percentage of social relation transfer, the number of individuals and the relative importance of nutritional requirements and social links influence the average number of days before irreversible fission occurs. The greater the nutritional needs and the higher the transfer of social relations during temporary fission, the fewer days will be observed before an irreversible fission. It is crucial to bridge the gap between the individual and the population level if we hope to understand how simple, local interactions may drive ecological systems.

  6. Structure and Dynamics of Humpback Whales Competitive Groups in Ecuador

    Directory of Open Access Journals (Sweden)

    Fernando Félix

    2015-02-01

    Full Text Available We assessed the social structure and behavior of humpback whale (Megaptera novaeangliae competitive groups off Ecuador between July and August 2010. During this time we followed 185 whales in 22 competitive groups for 41.45 hr. The average group size was 8.4 animals (SD = 2.85. The average sighting time was 113.05 min/group (SD = 47.1. We used photographs of dorsal fins and video to record interactions and estimate an association index (AI between each pair of whales within the groups. Sightings were divided into periods, which were defined by changes in group membership. On average, group composition changed every 30.2 min, which confirms that the structure of competitive groups is highly dynamic. Interactions between escorts characterized by low level of aggression. At least 60% of escorts joined or left together the group in small subunits between two and five animals, suggesting some type of cooperative association. Although singletons, as well as pairs or trios were able to join competitive groups at any moment, escorts that joined together were able to stay longer with the group and displace dominant escorts. Genetic analysis showed that in three occasions more than one female was present within a competitive group, suggesting either males are herding females or large competitive groups are formed by subunits. Males and females performed similar surface displays. We propose that competition and cooperation are interrelated in humpback whales’ competitive groups and that male cooperation would be an adaptive strategy either to displace dominant escorts or to fend off challengers.

  7. Dominance dynamics of competition between intrinsic and extrinsic grouping cues.

    Science.gov (United States)

    Luna, Dolores; Villalba-García, Cristina; Montoro, Pedro R; Hinojosa, José A

    2016-10-01

    In the present study we examined the dominance dynamics of perceptual grouping cues. We used a paradigm in which participants selectively attended to perceptual groups based on several grouping cues in different blocks of trials. In each block, single and competing grouping cues were presented under different exposure durations (50, 150 or 350ms). Using this procedure, intrinsic vs. intrinsic cues (i.e. proximity and shape similarity) were compared in Experiment 1; extrinsic vs. extrinsic cues (i.e. common region and connectedness) in Experiment 2; and intrinsic vs. extrinsic cues (i.e. common region and shape similarity) in Experiment 3. The results showed that in Experiment 1, no dominance of any grouping cue was found: shape similarity and proximity grouping cues showed similar reaction times (RTs) and interference effects. In contrast, in Experiments 2 and 3, common region dominated processing: (i) RTs to common region were shorter than those to connectedness (Exp. 2) or shape similarity (Exp. 3); and (ii) when the grouping cues competed, common region interfered with connectedness (Exp. 2) and shape similarity (Exp. 3) more than vice versa. The results showed that the exposure duration of stimuli only affected the connectedness grouping cue. An important result of our experiments indicates that when two grouping cues compete, both the non-attended intrinsic cue in Experiment 1, and the non-dominant extrinsic cue in Experiments 2 and 3, are still perceived and they are not completely lost. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Positive Nonlinear Dynamical Group Uniting Quantum Mechanics and Thermodynamics

    OpenAIRE

    Beretta, Gian Paolo

    2006-01-01

    We discuss and motivate the form of the generator of a nonlinear quantum dynamical group 'designed' so as to accomplish a unification of quantum mechanics (QM) and thermodynamics. We call this nonrelativistic theory Quantum Thermodynamics (QT). Its conceptual foundations differ from those of (von Neumann) quantum statistical mechanics (QSM) and (Jaynes) quantum information theory (QIT), but for thermodynamic equilibrium (TE) states it reduces to the same mathematics, and for zero entropy stat...

  9. Embracing Advocacy: How Visible Minority and Dominant Group Beginning Teachers Take Up Issues of Equity

    Directory of Open Access Journals (Sweden)

    Naomi Norquay

    2011-05-01

    Full Text Available This paper is from a four-year research project that followed graduates of a teacher education program from teacher certification through their first three years of teaching. It focuses on participants' narratives about their advocacy efforts in both their pre-service practicum placements and their first year as probationary teachers. Our findings indicate that while dominant group white participants chose to advocate from a position of personal conviction (often based on new knowledge of equity issues, the visible minority participants were often summoned by others to advocate. The paper concludes with a discussion about how teacher education might better address advocacy issues, alongside the focus on equity issues.

  10. AGRICULTURAL DYNAMICS IN PAKISTAN: CURRENT ISSUES AND SOLUTIONS

    Directory of Open Access Journals (Sweden)

    Fawad Zafar Ahmad Khan

    2013-08-01

    Full Text Available Agriculture is heavily contributing towards the economy of Pakistan. Water deficiency and drought conditions, long duration load shedding issue, poor extension services, absence of land reforms, absence of distribution of certified varieties, high price of fertilizers, deliberate use of adulterated, non-recommended and expired insecticides, non utilization of cultivable waste land, conventional farming practices, indirect access of farmer to main market, absence of ecological based cropping pattern, smuggling of agricultural inputs and outputs, lack of cooperation between agricultural research, education & extension services, absence of crop insurance, depletion of forests, lack of modern post-harvest technologies and disease outbreaks of poultry birds are some of the key issues that are playing a negative role in demotion of agricultural sector in Pakistan. The review article will briefly discuss above mentioned issues and some of the possible remedies under the environment of Pakistanand their adoption to improve the agricultural productivity in the country.

  11. Dynamical groups of a particle in a periodic potential

    International Nuclear Information System (INIS)

    Yusuf, M.

    1992-09-01

    Solving the Schroedinger non-relativistic equation of a particle moving under the influence of the potential V(θ) = ω(1 - cosθ) leads to us to the standard Mathieu equation. Jahnke-Emde's(1938), the periodic solutions are Mathieu functions of even order. With an approximation we study two important limiting cases, a simple quantum rotator and one-dimensional linear oscillator. We show the dynamical groups of these special, and a further study of the real problem connects us an Euclidean group of 2D. An IRR of matrix elements give us the energy levels. The interface between the E 2 and Bessel Functions is showed. (author). 7 refs

  12. Group dynamics for the acquisition of competences in Project Management

    Science.gov (United States)

    Taguas, E. V.; Aguilar, M. C.; Castillo, C.; Polo, M. J.; Pérez, R.

    2012-04-01

    The Bologna Process promotes European citizens' employability from teaching fields in the University which implies the design of activities addressed to the development of skills for the labor market and engagement of employers. This work has been conceived for improving the formation of Engineering Project Management through group dynamics focused on: 1) the use of the creativity for solving problems; 2) promoting leadership capacities and social skills in multidisciplinary/multicultural work groups; 3) the ethical, social and environmental compromise; 4) the continuous learning. Different types of activities were designed: short activities of 15-30 minutes where fragments of books or songs are presented and discussed and long activities (2 h) where groups of students take different roles for solving common problems and situations within the Engineering Projects context. An electronic book with the content of the dynamics and the material for the students has been carried out. A sample of 20 students of Electronic Engineering degree which had participated at least in two dynamics, evaluated the utility for improving their formation in Engineering Project Management with a mark of 8.2 (scale 0-10, standard deviation equal to 0.9). On the other hand, the teachers observed how this type of work, promotes the interdisciplinary training and the acquisition of social skills, usually not-included in the objectives of the subjects.

  13. Group theoretic reduction of Laplacian dynamical problems on fractal lattices

    International Nuclear Information System (INIS)

    Schwalm, W.A.; Schwalm, M.K.; Giona, M.

    1997-01-01

    Discrete forms of the Schroedinger equation, the diffusion equation, the linearized Landau-Ginzburg equation, and discrete models for vibrations and spin dynamics belong to a class of Laplacian-based finite difference models. Real-space renormalization of such models on finitely ramified regular fractals is known to give exact recursion relations. It is shown that these recursions commute with Lie groups representing continuous symmetries of the discrete models. Each such symmetry reduces the order of the renormalization recursions by one, resulting in a system of recursions with one fewer variable. Group trajectories are obtained from inverse images of fixed and invariant sets of the recursions. A subset of the Laplacian finite difference models can be mapped by change of boundary conditions and time dependence to a diffusion problem with closed boundaries. In such cases conservation of mass simplifies the group flow and obtaining the groups becomes easier. To illustrate this, the renormalization recursions for Green functions on four standard examples are decoupled. The examples are (1) the linear chain, (2) an anisotropic version of Dhar close-quote s 3-simplex, similar to a model dealt with by Hood and Southern, (3) the fourfold coordinated Sierpiacute nski lattice of Rammal and of Domany et al., and (4) a form of the Vicsek lattice. Prospects for applying the group theoretic method to more general dynamical systems are discussed. copyright 1997 The American Physical Society

  14. Dynamical networks of influence in small group discussions.

    Science.gov (United States)

    Moussaïd, Mehdi; Noriega Campero, Alejandro; Almaatouq, Abdullah

    2018-01-01

    In many domains of life, business and management, numerous problems are addressed by small groups of individuals engaged in face-to-face discussions. While research in social psychology has a long history of studying the determinants of small group performances, the internal dynamics that govern a group discussion are not yet well understood. Here, we rely on computational methods based on network analyses and opinion dynamics to describe how individuals influence each other during a group discussion. We consider the situation in which a small group of three individuals engages in a discussion to solve an estimation task. We propose a model describing how group members gradually influence each other and revise their judgments over the course of the discussion. The main component of the model is an influence network-a weighted, directed graph that determines the extent to which individuals influence each other during the discussion. In simulations, we first study the optimal structure of the influence network that yields the best group performances. Then, we implement a social learning process by which individuals adapt to the past performance of their peers, thereby affecting the structure of the influence network in the long run. We explore the mechanisms underlying the emergence of efficient or maladaptive networks and show that the influence network can converge towards the optimal one, but only when individuals exhibit a social discounting bias by downgrading the relative performances of their peers. Finally, we find a late-speaker effect, whereby individuals who speak later in the discussion are perceived more positively in the long run and are thus more influential. The numerous predictions of the model can serve as a basis for future experiments, and this work opens research on small group discussion to computational social sciences.

  15. Risk perception in an interest group context: an examination of the TMI restart issue

    International Nuclear Information System (INIS)

    Soderstrom, E.J.; Sorensen, J.H.; Copenhaver, E.D.; Carnes, S.A.

    1984-01-01

    Human response to environmental hazards and risks has been the subject of considerable research by social scientists. Work has traditionally focused on either individual response to the risks of an ongoing or future threat (hazards research), or group and organizational response to a specific disaster event (disaster research). As part of a larger investigation of the restart of the Unit 1 reactor at Three Mile Island (TMI), the response of interest groups active in the restart issue to the continued threat of TMI and to future risks due to restart was examined. After reviewing the restart issue in general, the local dimensions of the restart issue from interest group perspectives are discussed. A method for defining appropriate issues at the community level is reviewed. Differences in the perceived local impacts of alternative decisions, and systems of beliefs associated with differing perceptions are discussed. Finally, the implications of interest group versus individual perceptions of local issues for decision making about TMI, in particular, and about technological hazards management, in general, are discussed. Associated implications for determining socially acceptable risk levels are identified

  16. The messenger matters: Pollinator functional group influences mating system dynamics.

    Science.gov (United States)

    Weber, Jennifer J

    2017-08-01

    The incredible diversity of plant mating systems has fuelled research in evolutionary biology for over a century. Currently, there is broad concern about the impact of rapidly changing pollinator communities on plant populations. Very few studies, however, examine patterns and mechanisms associated with multiple paternity from cross-pollen loads. Often, foraging pollinators collect a mixed pollen load that may result in the deposition of pollen from different sires to receptive stigmas. Coincident deposition of self- and cross-pollen leads to interesting mating system dynamics and has been investigated in numerous species. But, mixed pollen loads often consist of a diversity of cross-pollen and result in multiple sires of seeds within a fruit. In this issue of Molecular Ecology, Rhodes, Fant, and Skogen () examine how pollinator identity and spatial isolation influence multiple paternity within fruits of a self-incompatible evening primrose. The authors demonstrate that pollen pool diversity varies between two pollinator types, hawkmoths and diurnal solitary bees. Further, progeny from more isolated plants were less likely to have multiple sires regardless of the pollinator type. Moving forward, studies of mating system dynamics should consider the implications of multiple paternity and move beyond the self- and cross-pollination paradigm. Rhodes et al. () demonstrate the importance of understanding the roles that functionally diverse pollinators play in mating system dynamics. © 2017 John Wiley & Sons Ltd.

  17. Social Group Dynamics and Patterns of Latin American Integration Processes

    Directory of Open Access Journals (Sweden)

    Sébastien Dubé

    2017-04-01

    Full Text Available This article proposes to incorporate social psychology elements with mainstream political science and international relations theories to help understand the contradictions related to the integration processes in Latin America. Through a theoretical analysis, it contributes to the challenge proposed by Dabène (2009 to explain the “resilience” of the Latin American regional integration process in spite of its “instability and crises.” Our main proposition calls for considering Latin America as a community and its regional organizations as “social groups.” In conclusion, three phenomena from the field of social psychology and particularly social group dynamics shed light on these contradictory patterns: the value of the group and the emotional bond, groupthink, and cognitive dissonance.

  18. Dynamical realizations of l-conformal Newton–Hooke group

    International Nuclear Information System (INIS)

    Galajinsky, Anton; Masterov, Ivan

    2013-01-01

    The method of nonlinear realizations and the technique previously developed in [A. Galajinsky, I. Masterov, Nucl. Phys. B 866 (2013) 212, (arXiv:1208.1403)] are used to construct a dynamical system without higher derivative terms, which holds invariant under the l-conformal Newton–Hooke group. A configuration space of the model involves coordinates, which parametrize a particle moving in d spatial dimensions and a conformal mode, which gives rise to an effective external field. The dynamical system describes a generalized multi-dimensional oscillator, which undergoes accelerated/decelerated motion in an ellipse in accord with evolution of the conformal mode. Higher derivative formulations are discussed as well. It is demonstrated that the multi-dimensional Pais–Uhlenbeck oscillator enjoys the l=3/2 -conformal Newton–Hooke symmetry for a particular choice of its frequencies

  19. Gender Gaps in Group Listening and Speaking: Issues in Social Constructivist Approaches to Teaching and Learning

    Science.gov (United States)

    Hunter, Darryl; Gambell, Trevor; Randhawa, Bikkar

    2005-01-01

    Because of its centrality to school success, social status, and workplace effectiveness, oral and aural skills development has been increasingly emphasized in Canadian curricula, classrooms and, very recently, large-scale assessment. The corresponding emphasis on group processes and collaborative learning has aimed to address equity issues in…

  20. Analyzing repeated measures data on individuals nested within groups: accounting for dynamic group effects.

    Science.gov (United States)

    Bauer, Daniel J; Gottfredson, Nisha C; Dean, Danielle; Zucker, Robert A

    2013-03-01

    Researchers commonly collect repeated measures on individuals nested within groups such as students within schools, patients within treatment groups, or siblings within families. Often, it is most appropriate to conceptualize such groups as dynamic entities, potentially undergoing stochastic structural and/or functional changes over time. For instance, as a student progresses through school, more senior students matriculate while more junior students enroll, administrators and teachers may turn over, and curricular changes may be introduced. What it means to be a student within that school may thus differ from 1 year to the next. This article demonstrates how to use multilevel linear models to recover time-varying group effects when analyzing repeated measures data on individuals nested within groups that evolve over time. Two examples are provided. The 1st example examines school effects on the science achievement trajectories of students, allowing for changes in school effects over time. The 2nd example concerns dynamic family effects on individual trajectories of externalizing behavior and depression. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  1. Teacher’s action zone in facilitating group dynamics

    Directory of Open Access Journals (Sweden)

    Dagmara Gałajda

    2012-01-01

    Full Text Available As believed by many researchers (Dörnyei & Murphey 2003, Hadfield 1992, classroom climate is strongly determined by the dynamics of the learning group and its development over time. For this reason, the role of the teacher in facilitating group processes seems to be of primary importance since it is the teacher who has long been regarded as the group leader in both teacher-centred and learner-centred classrooms.The presentation focuses not only on positive but also on negative forms of classroom dynamics together with management techniques for dealing with conflicts, educational alienation and psychological defensiveness. This, in turn, leads to the concept of facilitator style based on Heron’s (2006 model of facilitation, which consists of six dimensions and three modes. In the paper particular emphasis is placed on the presentation and comparison of various theories of leadership, namely Heron’s system of facilitation, Hersey and Blanchard’s situational-leadership theory (1982 and Bass and Avolio’s transactional versus transformational leadership theory (1984.

  2. Dense interstellar cloud chemistry: Basic issues and possible dynamical solution

    International Nuclear Information System (INIS)

    Prasad, S.S.; Heere, K.R.; Tarafdar, S.P.

    1989-01-01

    Standing at crossroad of enthusiasm and frustration, dense intertellar cloud chemistry has a squarely posed fundamental problem: Why do the grains appear to play at best a minor role in the chemistry? Grain surface chemistry creates considerable difficulties when the authors treat dense clouds as static objects and ignore the implications of the processes by which the clouds became dense in the first place. A new generation of models which treat chemical and dynamical evolutions concurrently are therefore presented as possible solution to the current frustrations. The proposed modeling philosophy and agenda could make the next decade quite exciting for interstellar chemistry

  3. Addressing Thermal and Performance Variability Issues in Dynamic Processors

    Energy Technology Data Exchange (ETDEWEB)

    Yoshii, Kazutomo [Argonne National Lab. (ANL), Argonne, IL (United States); Llopis, Pablo [Univ. Carlos III de Madrid (Spain); Zhang, Kaicheng [Northwestern Univ., Evanston, IL (United States); Luo, Yingyi [Northwestern Univ., Evanston, IL (United States); Ogrenci-Memik, Seda [Northwestern Univ., Evanston, IL (United States); Memik, Gokhan [Northwestern Univ., Evanston, IL (United States); Sankaran, Rajesh [Argonne National Lab. (ANL), Argonne, IL (United States); Beckman, Pete [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-03-01

    As CMOS scaling nears its end, parameter variations (process, temperature and voltage) are becoming a major concern. To overcome parameter variations and provide stability, modern processors are becoming dynamic, opportunistically adjusting voltage and frequency based on thermal and energy constraints, which negatively impacts traditional bulk-synchronous parallelism-minded hardware and software designs. As node-level architecture is growing in complexity, implementing variation control mechanisms only with hardware can be a challenging task. In this paper we investigate a software strategy to manage hardwareinduced variations, leveraging low-level monitoring/controlling mechanisms.

  4. Some Remarks on Group Bundles and C*-dynamical systems

    OpenAIRE

    Vasselli, Ezio

    2003-01-01

    We introduce the notion of fibred action of a group bundle on a C(X)-algebra. By using such a notion, a characterization in terms of induced C*-bundles is given for C*-dynamical systems such that the relative commutant of the fixed-point algebra is minimal (i.e., it is generated by the centre of the given C*-algebra and the centre of the fixed-point algebra). A class of examples in the setting of the Cuntz algebra is given, and connections with superselection structures with nontrivial centre...

  5. Some Remarks on Group Bundles and C* Dynamical Systems

    Science.gov (United States)

    Vasselli, Ezio

    2007-08-01

    We introduce the notion of fibred action of a group bundle on a C(X)-algebra. By using such a notion, a characterization in terms of induced C*-bundles is given for C*-dynamical systems such that the relative commutant of the fixed-point C*-algebra is minimal (i.e., it is generated by the centre of the given C*-algebra and the centre of the fixed-point C*-algebra). A class of examples in the setting of the Cuntz algebra is given, and connections with superselection structures with nontrivial centre are discussed.

  6. Issues in computational fluid dynamics code verification and validation

    Energy Technology Data Exchange (ETDEWEB)

    Oberkampf, W.L.; Blottner, F.G.

    1997-09-01

    A broad range of mathematical modeling errors of fluid flow physics and numerical approximation errors are addressed in computational fluid dynamics (CFD). It is strongly believed that if CFD is to have a major impact on the design of engineering hardware and flight systems, the level of confidence in complex simulations must substantially improve. To better understand the present limitations of CFD simulations, a wide variety of physical modeling, discretization, and solution errors are identified and discussed. Here, discretization and solution errors refer to all errors caused by conversion of the original partial differential, or integral, conservation equations representing the physical process, to algebraic equations and their solution on a computer. The impact of boundary conditions on the solution of the partial differential equations and their discrete representation will also be discussed. Throughout the article, clear distinctions are made between the analytical mathematical models of fluid dynamics and the numerical models. Lax`s Equivalence Theorem and its frailties in practical CFD solutions are pointed out. Distinctions are also made between the existence and uniqueness of solutions to the partial differential equations as opposed to the discrete equations. Two techniques are briefly discussed for the detection and quantification of certain types of discretization and grid resolution errors.

  7. Dynamical Cognitive Models of Social Issues in Russia

    Science.gov (United States)

    Mitina, Olga; Abraham, Fred; Petrenko, Victor

    We examine and model dynamics in three areas of social cognition: (1) political transformations within Russia, (2) evaluation of political trends in other countries by Russians, and (3) evaluation of Russian stereotypes concerning women. We try to represent consciousness as vectorfields and trajectories in a cognitive state space. We use psychosemantic techniques that allow definition of the state space and the systematic construction of these vectorfields and trajectories and their portrait from research data. Then we construct models to fit them, using multiple regression methods to obtain linear differential equations. These dynamical models of social cognition fit the data quite well. (1) The political transformations were modeled by a spiral repellor in a two-dimensional space of a democratic-totalitarian factor and social depression-optimism factor. (2) The evaluation of alien political trends included a flow away from a saddle toward more stable and moderate political regimes in a 2D space, of democratic-totalitarian and unstable-stable cognitive dimensions. (3) The gender study showed expectations (attractors) for more liberated, emancipated roles for women in the future.

  8. Transcultural group performance in extreme environment: Issues, concepts and emerging theory

    Science.gov (United States)

    Lapierre, Judith; Bouchard, Stéphane; Martin, Thibault; Perreault, Michel

    2009-06-01

    A simulation for flight of international crew on space station took place in Moscow from July 1999 to April 2000 (SFINCS) at the State Biomedical Institute of Russia (IBMP) isolation chambers. Objectives of this study were to identify concepts of psychosocial adaptation and of social interactions to develop an explanation of the transcultural group performance. Method: constructivist epistemology with grounded theory research and fourth generation evaluation were used. Data on processes and interactions were gathered during 110 days of confinement as a subject and extended to 240 days as an outside scientist. Results indicate that coping is influenced by usual coping strategies and coping behaviors inside. Several stresses and human factor issues were identified altering well being and performance inside the chambers. Enabling and limiting forces are discussed. A theory on transcultural group performance is proposed. Issues are raised that appear critical to selection, training and group performance.

  9. Robustness and Vulnerability of Networks with Dynamical Dependency Groups.

    Science.gov (United States)

    Bai, Ya-Nan; Huang, Ning; Wang, Lei; Wu, Zhi-Xi

    2016-11-28

    The dependency property and self-recovery of failure nodes both have great effects on the robustness of networks during the cascading process. Existing investigations focused mainly on the failure mechanism of static dependency groups without considering the time-dependency of interdependent nodes and the recovery mechanism in reality. In this study, we present an evolving network model consisting of failure mechanisms and a recovery mechanism to explore network robustness, where the dependency relations among nodes vary over time. Based on generating function techniques, we provide an analytical framework for random networks with arbitrary degree distribution. In particular, we theoretically find that an abrupt percolation transition exists corresponding to the dynamical dependency groups for a wide range of topologies after initial random removal. Moreover, when the abrupt transition point is above the failure threshold of dependency groups, the evolving network with the larger dependency groups is more vulnerable; when below it, the larger dependency groups make the network more robust. Numerical simulations employing the Erdős-Rényi network and Barabási-Albert scale free network are performed to validate our theoretical results.

  10. Renormalization group method in the theory of dynamical systems

    International Nuclear Information System (INIS)

    Sinai, Y.G.; Khanin, K.M.

    1988-01-01

    One of the most important events in the theory of dynamical systems for the last decade has become a wide penetration of ideas and renormalization group methods (RG) into this traditional field of mathematical physics. RG-method has been one of the main tools in statistical physics and it has proved to be rather effective while solving problems of the theory of dynamical systems referring to new types of bifurcations (see further). As in statistical mechanics the application of the RG-method is of great interest in the neighborhood of the critical point concerning the order-chaos transition. First the RG-method was applied in the pioneering papers dedicated to the appearance of a stochastical regime as a result of infinite sequences of period doubling bifurcations. At present this stochasticity mechanism is the most studied one and many papers deal with it. The study of the so-called intermittency phenomenon was the next example of application of the RG-method, i.e. the study of such a situation where the domains of the stochastical and regular behavior do alternate along a trajectory of the dynamical system

  11. Dynamical renormalization group approach to relaxation in quantum field theory

    International Nuclear Information System (INIS)

    Boyanovsky, D.; Vega, H.J. de

    2003-01-01

    The real time evolution and relaxation of expectation values of quantum fields and of quantum states are computed as initial value problems by implementing the dynamical renormalization group (DRG). Linear response is invoked to set up the renormalized initial value problem to study the dynamics of the expectation value of quantum fields. The perturbative solution of the equations of motion for the field expectation values of quantum fields as well as the evolution of quantum states features secular terms, namely terms that grow in time and invalidate the perturbative expansion for late times. The DRG provides a consistent framework to resum these secular terms and yields a uniform asymptotic expansion at long times. Several relevant cases are studied in detail, including those of threshold infrared divergences which appear in gauge theories at finite temperature and lead to anomalous relaxation. In these cases the DRG is shown to provide a resummation akin to Bloch-Nordsieck but directly in real time and that goes beyond the scope of Bloch-Nordsieck and Dyson resummations. The nature of the resummation program is discussed in several examples. The DRG provides a framework that is consistent, systematic, and easy to implement to study the non-equilibrium relaxational dynamics directly in real time that does not rely on the concept of quasiparticle widths

  12. Dynamic Group Diffie-Hellman Key Exchange under standard assumptions

    International Nuclear Information System (INIS)

    Bresson, Emmanuel; Chevassut, Olivier; Pointcheval, David

    2002-01-01

    Authenticated Diffie-Hellman key exchange allows two principals communicating over a public network, and each holding public-private keys, to agree on a shared secret value. In this paper we study the natural extension of this cryptographic problem to a group of principals. We begin from existing formal security models and refine them to incorporate major missing details (e.g., strong-corruption and concurrent sessions). Within this model we define the execution of a protocol for authenticated dynamic group Diffie-Hellman and show that it is provably secure under the decisional Diffie-Hellman assumption. Our security result holds in the standard model and thus provides better security guarantees than previously published results in the random oracle model

  13. Beam dynamics issues in an extended relativistic klystron

    International Nuclear Information System (INIS)

    Giordano, G.; Li, H.; Goffeney, N.; Henestroza, E.; Sessler, A.; Yu, S.

    1995-04-01

    Preliminary studies of beam dynamics in a relativistic klystron were done to support a design study for a 1 TeV relativistic klystron two-beam accelerator (RK-TBA), 11.424 GHz microwave power source. This paper updates those studies. An induction accelerator beam is modulated, accelerated to 10 MeV, and injected into the RK with a rf current of about 1.2 kA. The main portion of the RK is the 300-m long extraction section comprise of 150 traveling-wave output structures and 900 induction accelerator cells. A periodic system of permanent quadrupole magnets is used for focusing. One and two dimensional numerical studies of beam modulation, injection into the main RK, transport and longitudinal equilibrium are presented. Transverse beam instability studies including Landau damping and the ''Betatron Node Scheme'' are presented

  14. Using Small Models for Big Issues : Exploratory System Dynamics Modelling and Analysis for Insightful Crisis Management

    NARCIS (Netherlands)

    Pruyt, E.

    2010-01-01

    The main goal of this paper is to explain and illustrate different exploratory uses of small System Dynamics models for analysis and decision support in case of dynamically complex issues that are deeply uncertain. The applied focuss of the paper is the field of inter/national safety and security.

  15. Small System dynamics models for big issues : Triple jump towards real-world complexity

    NARCIS (Netherlands)

    Pruyt, E.

    2013-01-01

    System Dynamics (SD) is a method to describe, model, simulate and analyze dynamically complex issues and/or systems in terms of the processes, information, organizational boundaries and strategies. Quantitative SD modeling, simulation and analysis facilitates the (re)design of systems and design of

  16. Dynamical renormalization group resummation of finite temperature infrared divergences

    International Nuclear Information System (INIS)

    Boyanovsky, D.; Vega, H.J. de; Boyanovsky, D.; Simionato, M.; Holman, R.; Simionato, M.

    1999-01-01

    We introduce the method of dynamical renormalization group to study relaxation and damping out of equilibrium directly in real time and apply it to the study of infrared divergences in scalar QED. This method allows a consistent resummation of infrared effects associated with the exchange of quasistatic transverse photons and leads to anomalous logarithmic relaxation of the form e -αampersandhthinsp;Tampersandhthinsp;tampersandhthinsp;ln[t/t 0 ] for hard momentum charged excitations. This is in contrast with the usual quasiparticle interpretation of charged collective excitations at finite temperature in the sense of exponential relaxation of a narrow width resonance for which the width is the imaginary part of the self-energy on shell. In the case of narrow resonances away from thresholds, this approach leads to the usual exponential relaxation. The hard thermal loop resummation program is incorporated consistently into the dynamical renormalization group yielding a picture of relaxation and damping phenomena in a plasma in real time that transcends the conceptual limitations of the quasiparticle picture and other types of resummation schemes. copyright 1999 The American Physical Society

  17. Avoiding Pitfalls and Realising Opportunities: Reflecting on Issues of Sampling and Recruitment for Online Focus Groups.

    Science.gov (United States)

    Boydell, Nicola; Fergie, Gillian; McDaid, Lisa; Hilton, Shona

    2014-02-01

    The increasing prominence of the Internet in everyday life has prompted methodological innovations in qualitative research, particularly the adaptation of established methods of data collection for use online. The alternative online context brings with it both opportunities and challenges. To date the literature on online focus groups has focused mainly on the suitability of the method for qualitative data collection, and the development of approaches to facilitation that maximise interaction. By reflecting on our experiences of designing and attempting to recruit participants to online focus groups for two exploratory research projects, we aim to contribute some novel reflections around the less articulated issues of sampling and recruitment for online focus groups. In particular, we highlight potentially problematic issues around offline recruitment for an online method of data collection; the potential of using social media for recruitment; and the uncertainties around offering incentives in online recruitment, issues which have received little attention in the growing literature around online focus groups. More broadly, we recommend continued examination of online social practices and the social media environment to develop appropriate and timely online recruitment strategies and suggest further areas for future research and innovation.

  18. Avoiding Pitfalls and Realising Opportunities: Reflecting on Issues of Sampling and Recruitment for Online Focus Groups

    Directory of Open Access Journals (Sweden)

    Nicola Boydell MSc

    2014-02-01

    Full Text Available The increasing prominence of the Internet in everyday life has prompted methodological innovations in qualitative research, particularly the adaptation of established methods of data collection for use online. The alternative online context brings with it both opportunities and challenges. To date the literature on online focus groups has focused mainly on the suitability of the method for qualitative data collection, and the development of approaches to facilitation that maximise interaction. By reflecting on our experiences of designing and attempting to recruit participants to online focus groups for two exploratory research projects, we aim to contribute some novel reflections around the less articulated issues of sampling and recruitment for online focus groups. In particular, we highlight potentially problematic issues around offline recruitment for an online method of data collection; the potential of using social media for recruitment; and the uncertainties around offering incentives in online recruitment, issues which have received little attention in the growing literature around online focus groups. More broadly, we recommend continued examination of online social practices and the social media environment to develop appropriate and timely online recruitment strategies and suggest further areas for future research and innovation.

  19. A REVIEW OF SELF HELP GROUPS: ISSUE AND CHALLENGES IN INDIA

    OpenAIRE

    Anoop Dixit *, Dr. S. K. Sharma

    2017-01-01

    Basic purpose of this study is to review the challenges and issues faced by SHGs in India. It was found that SHG’s facilitated the members to become self dependent for solving their social & economic problems and enhances the social status of members by virtue of their being members to the group. Self help groups are small informal association of the poor created at the grass root level for the purpose of enabling members to reap economic benefits out of mutual help solidarity and joint respo...

  20. Association of American Geographers, Remote Sensing Specialty Group Special Issue of Geocarto International

    Science.gov (United States)

    Allen, Thomas R. (Editor); Emerson, Charles W. (Editor); Quattrochi, Dale A. (Editor); Arnold, James E. (Technical Monitor)

    2001-01-01

    This special issue continues the precedence of the Association of American Geographers (AAG), Remote Sensing Specialty Group (RSSG) for publishing selected articles in Geocarto International as a by-product from the AAG annual meeting. As editors, we issued earlier this year, a solicitation for papers to be published in a special issue of Geocarto International that were presented in RSSG-sponsored sessions at the 2001 AAG annual meeting held in New York City on February 27-March 3. Although not an absolute requisite for publication, the vast majority of the papers in this special issue were presented at this year's AAG meeting in New York. Other articles in this issue that were not part of a paper or poster session at the 2001 AAG meeting are authored by RSSG members. Under the auspices of the RSSG, this special Geocarto International issue provides even more compelling evidence of the inextricable linkage between remote sensing and geography. The papers in this special issue fall into four general themes: 1) Urban Analysis and Techniques for Urban Analysis; 2) Land Use/Land Cover Analysis; 3) Fire Modeling Assessment; and 4) Techniques. The first four papers herein are concerned with the use of remote sensing for analysis of urban areas, and with use or development of techniques to better characterize urban areas using remote sensing data. As the lead paper in this grouping, Rashed et al., examine the usage of spectral mixture analysis (SMA) for analyzing satellite imagery of urban areas as opposed to more 'standard' methods of classification. Here SMA has been applied to IRS-1C satellite multispectral imagery to extract measures that better describe the 'anatomy' of the greater Cairo, Egypt region. Following this paper, Weng and Lo describe how Landsat TM data have been used to monitor land cover types and to estimate biomass parameters within an urban environment. The research reported in this paper applies an integrated GIS (Geographic Information System

  1. Combustion Dynamics Facility: April 1990 workshop working group reports

    Energy Technology Data Exchange (ETDEWEB)

    Kung, A.H.; Lee, Y.T.

    1990-04-01

    This document summarizes results from a workshop held April 5--7, 1990, on the proposed Combustion Dynamics Facility (CDF). The workshop was hosted by the Lawrence Berkeley Laboratory (LBL) and Sandia National Laboratories (SNL) to provide an opportunity for potential users to learn about the proposed experimental and computational facilities, to discuss the science that could be conducted with such facilities, and to offer suggestions as to how the specifications and design of the proposed facilities might be further refined to address the most visionary scientific opportunities. Some 130 chemical physicists, combustion chemists, and specialists in UV synchrotron radiation sources and free-electron lasers (more than half of whom were from institutions other than LBL and SNL) attended the five plenary sessions and participated in one or more of the nine parallel working group sessions. Seven of these sessions were devoted to broadening and strengthening the scope of CDF scientific opportunities and to detail the experimental facilities required to realize these opportunities. Two technical working group sessions addressed the design and proposed performance of two of the major CDF experimental facilities. These working groups and their chairpersons are listed below. A full listing of the attendees of the workshop is given in Appendix A. 1 tab.

  2. Some ethical issues in feminist-oriented therapeutic groups for women.

    Science.gov (United States)

    Lakin, M

    1991-04-01

    Review of the origins of group psychotherapy reveals concerns with social as well as with personal "psychopathology." Thus, group processes have been mobilized for curative or change purposes for ideological as well as individual therapeutic goals. Psychopolitical as well as personal change are the goals for some groups. The ethical problem stems from a persistent assumption that the group's processes are inherently benign and curative and beneficial to individual participants. A more sophisticated understanding takes into account their essential neutrality and their potential use (or abuse) for purposes of ideological persuasion that may or may not be personally therapeutic. As in other ethically implicated issues in the psychotherapies, the question becomes one of treatment versus exploitation, or therapy for the individual versus recruitment on behalf of a cause.

  3. A Group Creativity Support System for Dynamic Idea Evaluation

    DEFF Research Database (Denmark)

    Ulrich, Frank

    2015-01-01

    Idea evaluation is necessary in most modern organizations to identify the level of novelty and usefulness of new ideas. However, current idea evaluation research hinders creativity by primarily supporting convergent thinking (narrowing down ideas to a few tangible solutions), while divergent...... thinking (the development of wildly creative and novel thoughts patterns) is discounted. In this paper, this current view of idea evaluation is challenged through the development of a prototype that supports dynamic idea evaluation. The prototype uses knowledge created during evaluative processes...... to facilitate divergent thinking in a Group Creativity Support System (GCSS) designed from state-of-the-art research. The prototype is interpretively explored through a field experiment in a Danish IS research department. Consequently, the prototype demonstrates the ability to including divergent thinking...

  4. Contemporary Issues in Group Learning in Undergraduate Science Classrooms: A Perspective from Student Engagement.

    Science.gov (United States)

    Hodges, Linda C

    2018-06-01

    As the use of collaborative-learning methods such as group work in science, technology, engineering, and mathematics classes has grown, so has the research into factors impacting effectiveness, the kinds of learning engendered, and demographic differences in student response. Generalizing across the range of this research is complicated by the diversity of group-learning approaches used. In this overview, I discuss theories of how group-work formats support or hinder learning based on the ICAP (interactive, constructive, active, passive) framework of student engagement. I then use this model to analyze current issues in group learning, such as the nature of student discourse during group work, the role of group learning in making our classrooms inclusive, and how classroom spaces factor into group learning. I identify key gaps for further research and propose implications from this research for teaching practice. This analysis helps identify essential, effective, and efficient features of group learning, thus providing faculty with constructive guidelines to support their work and affirm their efforts.

  5. Working group II report: Production and dynamics of high brightness beams

    International Nuclear Information System (INIS)

    Sheffield, R.L.

    1996-01-01

    This paper summarizes the main discussions of the Working Group on the Production and Dynamics of High Brightness Beams. The following topics are covered in this paper. Proposed new electron sources and needed research on existing sources is covered. The discussions on issues relating to the description of phase space on non-thermalized electron beam distributions and the theoretical modeling on non-thermalized electron beam distributions is presented. Finally, the present status of the theoretical modeling of beam transport in bends is given

  6. Interactive affective sharing versus non-interactive affective sharing in work groups : Comparative effects of group affect on work group performance and dynamics

    NARCIS (Netherlands)

    Klep, Annefloor; Wisse, Barbara; Van Der Flier, Henk

    This study explores whether the dynamic path to group affect, which is characterized by interactive affective sharing processes, yields different effects on task performance and group dynamics than the static path to group affect, which arises from non-interactive affective sharing. The results of

  7. Interactive affective sharing versus non-interactive affective sharing in work groups: Comparative effects of group affect on work group performance and dynamics

    NARCIS (Netherlands)

    Klep, A.H.M.; Wisse, B.M.; van der Flier, H.

    2011-01-01

    This study explores whether the dynamic path to group affect, which is characterized by interactive affective sharing processes, yields different effects on task performance and group dynamics than the static path to group affect, which arises from non-interactive affective sharing. The results of

  8. EDITORIAL: Special issue on applied neurodynamics: from neural dynamics to neural engineering Special issue on applied neurodynamics: from neural dynamics to neural engineering

    Science.gov (United States)

    Chiel, Hillel J.; Thomas, Peter J.

    2011-12-01

    isolated spinal cord preparation from the cat) occurred only over a narrow range of supra-spinal drives compared to those supporting normal locomotion in a preparation in which feedback from the limb to the spinal cord was kept intact. The mechanisms by which locomotory behavior can be maintained, both under normal conditions and under reduced supraspinal drive (representing the effects of spinal cord injury (SCI)) are important building blocks for rehabilitative therapy post-SCI. Spardy et al (2011a, 2011b) analyze afferent control in a neuromechanical model of limbed locomotion that addresses these experimental results directly. Using sophisticated mathematical techniques from dynamical systems analysis, such as dissection of the dynamics into fast and slow subsystems, they are able to stitch together the geometry underlying transitions between different combinations of flexor/extensor activation and stance/swing phases of limb movement. Their analysis explains how peripheral feedback extends the range of supraspinal drives for which stable oscillations occur. In fact, they identify qualitatively distinct mechanisms by which the CPG creates rhythmic behavior in the presence and absence of feedback; in one case, the timing is determined by release from inhibition, and in the other case, escape from inhibition. In a companion paper, this same group carries out a further analysis of the locomotory control system, allowing them to resolve the following issue. As running speed increases, the durations of different component phases of the motion (stance/swing) do not change symmetrically. Instead, increase in velocity of forward motion is accomplished by decreasing the stance phase duration while the swing phase duration remains roughly constant. How is it that a CPG built of symmetrically related elements (flexor/extensor related rhythm generation neurons and interneurons), and symmetric descending drive, is able to produce asymmetric cycles? By finding a reduced model that

  9. Report of the working group on single-particle nonlinear dynamics

    International Nuclear Information System (INIS)

    Bazzani, A.; Bongini, L.; Corbett, J.; Dome, G.; Fedorova, A.; Freguglia, P.; Ng, K.; Ohmi, K.; Owen, H.; Papaphilippou, Y.; Robin, D.; Safranek, J.; Scandale, W.; Terebilo, A.; Turchetti, G.; Todesco, E.; Warnock, R.; Zeitlin, M.

    1999-01-01

    The Working Group on single-particle nonlinear dynamics has developed a set of tools to study nonlinear dynamics in a particle accelerator. The design of rings with large dynamic apertures is still far from automatic. The Working Group has concluded that nonlinear single-particle dynamics limits the performance of accelerators. (AIP) copyright 1999 American Institute of Physics

  10. Second Language Developmental Dynamics: How Dynamic Systems Theory Accounts for Issues in Second Language Learning

    Science.gov (United States)

    Rosmawati

    2014-01-01

    Dynamic systems theory (DST) is presented in this article as a suitable approach to research the acquisition of second language (L2) because of its close alignment with the process of second language learning. Through a process of identifying and comparing the characteristics of a dynamic system with the process of L2 learning, this article…

  11. Facebook Groups as a Powerful and Dynamic Tool in Medical Education: Mixed-Method Study

    Science.gov (United States)

    Schmidbauer, Moritz; Gradel, Maximilian; Ferch, Sabine; Antón, Sofía; Hoppe, Boj; Pander, Tanja; von der Borch, Philip; Pinilla, Severin; Fischer, Martin; Dimitriadis, Konstantinos

    2017-01-01

    categories ranged between 78% (11/14) and 100% (13/13), and the number of comments per post ranged from 8.4 to 13.7 compared with the average overall reply rate of 68.69% (1167/1699) and 3.9 comments per post. User typology revealed social media drivers (>30 posts per semester) as engines of group function, frequent users (11-30 posts), and a majority of average users acting rather as consumers or lurkers (1-10 posts). Conclusions For the moment, the medical faculty has no active involvement in these groups and therefore no influence on accuracy of information, professionalism, and ethical issues. Nevertheless, faculty could in the future benefit by extracting relevant information, identifying common problems, and understanding semester-related dynamics. PMID:29273572

  12. The uranium institute transport working group: a common approach to global issues

    International Nuclear Information System (INIS)

    Tissot-Colle, C.

    1998-01-01

    With more than 442 nuclear power plants in operation all over the world delivering clean and safe electricity on a daily basis, nuclear energy is and will undoubtedly be one of the most promising way to cope with present and future economic, demographic, and environmental challenges. Nuclear materials transportation business links the various nuclear actors: research institutes, utilities, fuel cycle industries, and waste management agencies. As pipelines or tankers for the petroleum industry, transportation gives nuclear energy its consistency. Still, conversely to other industrial areas, transportation volumes and figures are rather low in the nuclear business. For instance, transport of dangerous goods in France represents around 15 million packages per year. Out of this, only 15,000 or 0.1 % are nuclear fuel cycle materials. When applied to the USA, this figure is even more striking: 100 million of dangerous goods containers are shipped each year. Only 10,000 pertains to nuclear fuel cycle materials. Even so, in our world of economic and cultural globalization, transport of nuclear materials is no longer a domestic issue. It crosses boundaries and appeals to various areas ranging from safety to communication. That is why the Uranium Institute decided, in 1995, to set up a working group dedicated to transport issues. This paper covers the Uranium Institute Transport Working Group, from its creation to its most recent achievements. (author)

  13. Membership status and subjective group dynamics: who triggers the black sheep effect?

    Science.gov (United States)

    Pinto, Isabel R; Marques, José M; Levine, John M; Abrams, Dominic

    2010-07-01

    In 3 experiments, participants (Ns = 50, 95, and 75, respectively) judged 2 ingroup or outgroup members who occupied 1 of 3 statuses--new members, full members, or marginal members. In each case, 1 of these members adopted a normative position and another supported a deviant position regarding a relevant issue. Participants upgraded normative ingroup full members and derogated deviant ingroup full members compared with all other members. In addition, derogation of deviant ingroup members was associated with a socializing and a punishing intention toward new members and full members, respectively. These results are discussed in terms of the group socialization model (e.g., Levine & Moreland, 1994) and the subjective group dynamics model (e.g., Marques, Paez, & Abrams, 1998).

  14. Team Dynamics. Essays in the Sociology and Social Psychology of Sport Including Methodological and Epistemological Issues.

    Science.gov (United States)

    Lenk, Hans

    This document contains nine essays on the sociology and social psychology of team dynamics, including methodological and epistemological issues involved in such study. Essay titles are: (1) Conflict and Achievement in Top Athletic Teams--Sociometric Structures of Racing Eight Oar Crews; (2) Top Performance Despite Internal Conflict--An Antithesis…

  15. Social dynamics interest groups in a model of spatial competition

    NARCIS (Netherlands)

    Tuinstra, J.; Sadiraj, V.; van Winden, F.A.A.M.

    2000-01-01

    A well-known result in spatial voting theory is that, for a one-dimensional issue space and under certain mild conditions, political parties choose platforms coinciding with the median voter's position. This result does not carry over to multi-dimensional issue spaces however, since then an

  16. The positive group affect spiral : a dynamic model of the emergence of positive affective similarity in work groups

    NARCIS (Netherlands)

    Walter, F.; Bruch, H.

    This conceptual paper seeks to clarify the process of the emergence of positive collective affect. Specifically, it develops a dynamic model of the emergence of positive affective similarity in work groups. It is suggested that positive group affective similarity and within-group relationship

  17. Strong dynamics at the muon collider: Working group report

    International Nuclear Information System (INIS)

    Bhat, P.C.; Eichten, E.

    1998-03-01

    New strong dynamics at the energy scale ∼ 1 TeV is an attractive and elegant theoretical ansatz for the origin of electroweak symmetry breaking. We review here, the theoretical models for strong dynamics, particularly, technicolor theories and their low energy signatures. We emphasize that the fantastic beam energy resolution (σ E /E ∼ 10 -4 ) expected at the first muon collider (√s=100-500 GeV) allows the possibility of resolving some extraordinarily narrow technihadron resonances and, Higgs-like techniscalars produced in the s-channel. Investigating indirect probes for strong dynamics such as search for muon compositeness, we find that the muon colliders provide unparalleled reaches. A big muon collider (√s=3-4 TeV) would be a remarkable facility to study heavy technicolor particles such as the topcolor Z', to probe the dynamics underlying fermion masses and mixings and to fully explore the strongly interacting electroweak sector

  18. Reducing Deviance Through Youths' Mutual Aid Group Dynamics.

    Science.gov (United States)

    Cheung, Chau-kiu; Ngai, Steven Sek-yum

    2016-01-01

    The mutual aid group, as supported by the social worker, emerges to play a vital role in helping group members reduce their deviance or behavioral problem. However, how the collaboration of the group and social worker accomplishes the reduction has remained uncharted. Based on social capital theory, mutual aid and cohesion within the group and social workers' specific aid for the group are likely responsible for the reduction. The test of such hypotheses relies on a two-wave panel survey of the members of 60 mutual aid groups who had deviant behavioral problems, located in Hong Kong, China. These groups had 241 youths completing both initial and 1-year follow-up surveys. Results manifested the direct or unconditional contributions of mutual aid, group cohesion, and social workers' specific aid to reducing deviance. Hence, social workers can enhance the effectiveness of the mutual aid group in reducing youths' deviance. © The Author(s) 2014.

  19. Evaluation of the performance of diagnosis-related groups and similar casemix systems: methodological issues.

    Science.gov (United States)

    Palmer, G; Reid, B

    2001-05-01

    With the increasing recognition and application of casemix for managing and financing healthcare resources, the evaluation of alternative versions of systems such as diagnosis-related groups (DRGs) has been afforded high priority by governments and researchers in many countries. Outside the United States, an important issue has been the perceived need to produce local versions, and to establish whether or not these perform more effectively than the US-based classifications. A discussion of casemix evaluation criteria highlights the large number of measures that may be used, the rationale and assumptions underlying each measure, and the problems in interpreting the results. A review of recent evaluation studies from a number of countries indicates that considerable emphasis has been placed on the predictive validity criterion, as measured by the R2 statistic. However, the interpretation of the findings has been affected greatly by the methods used, especially the treatment and definition of outlier cases. Furthermore, the extent to which other evaluation criteria have been addressed has varied widely. In the absence of minimum evaluation standards, it is not possible to draw clear-cut conclusions about the superiority of one version of a casemix system over another, the need for a local adaptation, or the further development of an existing version. Without the evidence provided by properly designed studies, policy-makers and managers may place undue reliance on subjective judgments and the views of the most influential, but not necessarily best informed, healthcare interest groups.

  20. Theory and analysis of nonlinear dynamics and stability in storage rings: A working group summary

    International Nuclear Information System (INIS)

    Chattopadhyay, S.; Audy, P.; Courant, E.D.

    1988-07-01

    A summary and commentary of the available theoretical and analytical tools and recent advances in the nonlinear dynamics, stability and aperture issues in storage rings are presented. 11 refs., 4 figs

  1. Engineering science research issues in high power density transmission dynamics for aerospace applications. [rotorcraft geared rotors

    Science.gov (United States)

    Singh, Rajendra; Houser, Donald R.

    1993-01-01

    This paper discusses analytical and experimental approaches that will be needed to understand dynamic, vibro-acoustic and design characteristics of high power density rotorcraft transmissions. Complexities associated with mathematical modeling of such systems will be discussed. An overview of research work planned during the next several years will be presented, with emphasis on engineering science issues such as gear contact mechanics, multi-mesh drive dynamics, parameter uncertainties, vibration transmission through bearings, and vibro-acoustic characteristics of geared rotor systems and housing-mount structures. A few examples of work in progress are cited.

  2. Measuring Group Work Dynamics and Its Relation with L2 Learners' Task Motivation and Language Production

    Science.gov (United States)

    Poupore, Glen

    2016-01-01

    While learners of a second language (L2) are increasingly interacting in small groups as part of a communicative methodological paradigm, very few studies have investigated the social dynamics that occur in such groups. The aim of this study is to introduce a group work dynamic measuring instrument and to investigate the relationship between group…

  3. Relativistic kinematics and dynamics: a new group theoretical approach

    International Nuclear Information System (INIS)

    Giovannini, N.

    1983-01-01

    The author reanalyzes the relationships between physical states and space-time symmetries with a view to describing relativistic extended and interacting systems. For this description he proposes to introduce, in space-time, an additional observable, related to a natural notion of simultaneity. The introduction of this new observable is justified on the basis of the operational meaning of the relations between state descriptions and symmetries in this case. The Poincare transformations are correspondingly split into two parts: the first one, kinematical, related to the symmetries of the description of the states, the other one, dynamical, related to the possible forms for the evolution. It is shown that the kinematical symmetries lead in a straightforward way to the expected classical and quantal state spaces for single particles of arbitrary spin and the author shows how the remaining symmetries can be related to the derivation of the possible forms for the dynamics. He finds as a particular case the usual dynamics of single particles in external fields (with some satisfactory improvements due to the corresponding new interpretation) and extends the method to the dynamics of N interacting particles. He also shows why this new approach and interpretation of relativistic states is necessary and how it allows a covariant description in the problems raised by the (recently measured) quantum correlations at-a-distance concerning the Einstein-Podolsky-Rosen paradox, something which seems quite impossible in the usual frameworks. (Auth.)

  4. Materials compatibility issues related to thermal energy storage for a space solar dynamic power system

    Science.gov (United States)

    Faget, N. M.

    1986-01-01

    Attention is given to results obtained to date in developmental investigations of a thermal energy storage (TES) system for the projected NASA Space Station's solar dynamic power system; these tests have concentrated on issues related to materials compatibility for phase change materials (PCMs) and their containment vessels' materials. The five PCMs tested have melting temperatures that correspond to the operating temperatures of either the Brayton or Rankine heat engines, which were independently chosen for their high energy densities.

  5. Dynamic security issues in autonomous power systems with increasing wind power penetration

    DEFF Research Database (Denmark)

    Margaris, I.D.; Hansen, Anca Daniela; Sørensen, Poul Ejnar

    2011-01-01

    Asynchronous Generator (DFAG) and Permanent Magnet Synchronous Generator (PMSG) – are applied and issues regarding interaction with the power system are investigated. This paper provides conclusions about the dynamic security of non-interconnected power systems with high wind power penetration based...... on a complete model representation of the individual components of the system; three different types of conventional generators are included in the model, while the protection system is also incorporated. The load shedding following faults is finally discussed....

  6. How milk-fed dairy calves perform in stable versus dynamic groups

    DEFF Research Database (Denmark)

    Pedersen, Rikke Engelbrecht; Sørensen, Jan Tind; Skjøth, F

    2009-01-01

    The objective of the present field trial was to compare calf performance among pre-weaned calves in two different group housing systems, stable groups ("all in-all out") and dynamic groups (continuous introduction). Performance data was collected from 484 calves randomly assigned to the two syste....../days). The prevalence of both diarrhoea and respiratory disease were more than twice as high among calves in dynamic groups compared to calves in stable groups....

  7. A dynamic new group within Human Resources Division

    CERN Multimedia

    2003-01-01

    Since 1st May CERN's training and development and personnel management teams have been fused into a new group called Personnel Management and Development. The new Personnel Management and Development Group is responsible for career advancement and management, recruitment, remuneration and for language, communication, management, academic and technical training, keys to a sense of greater well-being and to career progression. The new group was born on 1st May out of the fusion of the "Personnel Management" and "Training and Development" Groups within CERN's Human Resources Division. Its aim is to offer a practical and easily accessible service to assist the members of the personnel and supervisors to manage careers more harmoniously, to make progress and to continue to learn on the job. With Sue Foffano as its Group Leader, the Group comprises four sections: Academic and Technical Training under the guiding hand of Mick Storr; Management, Communication and Language Training headed by Sudeshna Datta-Cockeril...

  8. Challenging gender stereotypes: Theory of mind and peer group dynamics.

    Science.gov (United States)

    Mulvey, Kelly Lynn; Rizzo, Michael T; Killen, Melanie

    2016-11-01

    To investigate the social cognitive skills related to challenging gender stereotypes, children (N = 61, 3-6 years) evaluated a peer who challenged gender stereotypic norms held by the peer's group. Participants with false belief theory of mind (FB ToM) competence were more likely than participants who did not have FB ToM to expect a peer to challenge the group's stereotypes and propose that the group engage in a non-stereotypic activity. Further, participants with FB ToM rated challenging the peer group more positively. Participants without FB ToM did not differentiate between their own and the group's evaluation of challenges to the group's stereotypic norms, but those with ToM competence asserted that they would be more supportive of challenging the group norm than would the peer group. Results reveal the importance of social-cognitive competencies for recognizing the legitimacy of challenging stereotypes, and for understanding one's own and other group perspectives. © 2015 John Wiley & Sons Ltd.

  9. Team confidence, motivated information processing, and dynamic group decision making

    NARCIS (Netherlands)

    de Dreu, C.K.W.; Beersma, B.

    2010-01-01

    According to the Motivated Information Processing in Groups (MIP-G) model, groups should perform ambiguous (non-ambiguous) tasks better when they have high (low) epistemic motivation and concomitant tendencies to engage in systematic (heuristic) information processing and exchange. The authors

  10. Dynamical behavior of price forecasting in structures of group correlations

    Science.gov (United States)

    Lim, Kyuseong; Kim, Soo Yong; Kim, Kyungsik

    2015-07-01

    We investigate the prediction of the future prices from the structures and the networks of the companies in special financial groups. After the financial group network has been constructed from the value of the high cross-correlation, each company in a group is simulated and analyzed how it buys or sells stock is anaylzed and how it makes rational investments is forecasted. In the shortmemory behavior rather than the long-memory behavior, each company among a group can make a rational investment decision by using a stochastic evolution rule in the financial network. In particular, we simulate and analyze the investment situation in connection with the empirical data and the simulated result.

  11. Dynamical Encoding by Networks of Competing Neuron Groups: Winnerless Competition

    International Nuclear Information System (INIS)

    Rabinovich, M.; Volkovskii, A.; Lecanda, P.; Huerta, R.; Abarbanel, H. D. I.; Laurent, G.

    2001-01-01

    Following studies of olfactory processing in insects and fish, we investigate neural networks whose dynamics in phase space is represented by orbits near the heteroclinic connections between saddle regions (fixed points or limit cycles). These networks encode input information as trajectories along the heteroclinic connections. If there are N neurons in the network, the capacity is approximately e(N-1) ! , i.e., much larger than that of most traditional network structures. We show that a small winnerless competition network composed of FitzHugh-Nagumo spiking neurons efficiently transforms input information into a spatiotemporal output

  12. Group Counseling in the Schools: Considerations for Child and Family Issues

    Science.gov (United States)

    Crespi, Tony D.; Gustafson, Amy L.; Borges, Silvia M.

    2006-01-01

    School psychologists are increasingly being confronted with a wide spectrum of psychological, psychosocial, familial, and home-school issues impacting child development. With one in six children raised in alcoholic families, with divorce impacting approximately 60% of families, and with such issues as teenage pregnancy, parental neglect, as well…

  13. Transference and Countertransference Issues Unique to Long-Term Group Psychotherapy of Adult Women Molested as Children: Trials and Rewards.

    Science.gov (United States)

    Abney, Veronica D.; And Others

    1992-01-01

    Discusses transference and countertransference issues associated with long-term psychodynamic group treatment of adult women molested as children. Describes and examines these women's transference reactions toward group members and the therapist. Also explores the specific effects of race and ethnicity, sexual orientation, and gender of the…

  14. The balancing act of establishing a policy agenda : Conceptualizing and measuring drivers of issue prioritization within interest groups

    NARCIS (Netherlands)

    Halpin, D.R.; Fraussen, B.; Nownes, A.J.

    2017-01-01

    Interest groups are important intermediaries in Western democracies, with the potential to offer political linkage and form a bridge between the concerns of citizens and the agendas of political elites. While we know an increasing amount about the issue-based activity of groups, we only have a

  15. Effects of Exposure to Environmental Groups on Student Awareness of Environmental Issues and Their Desire to Be Locally Involved

    Science.gov (United States)

    Burke, Ann M.

    2017-01-01

    This study investigated changes in high school students' awareness of environmental issues and their intent to be involved with local environmental groups after attendance at an environmental fair that exposed them to local environmental groups. A comparison of prefair and postfair surveys given to students indicated a highly significant increase…

  16. External evaluation of the Radiation Therapy Oncology Group brachial plexus contouring protocol: several issues identified

    International Nuclear Information System (INIS)

    Min, Myo; Carruthers, Scott; Zanchetta, Lydia; Roos, Daniel; Keating, Elly; Shakeshaft, John; Baxi, Siddhartha; Penniment, Michael; Wong, Karen

    2014-01-01

    The aims of the study were to evaluate interobserver variability in contouring the brachial plexus (BP) using the Radiation Therapy Oncology Group (RTOG)-approved protocol and to analyse BP dosimetries. Seven outliners independently contoured the BPs of 15 consecutive patients. Interobserver variability was reviewed qualitatively (visually by using planning axial computed-tomography images and anteroposterior digitally reconstructed radiographs) and quantitatively (by volumetric and statistical analyses). Dose–volume histograms of BPs were calculated and compared. We found significant interobserver variability among outliners in both qualitative and quantitative analyses. These were most pronounced for the T1 nerve roots on visual inspection and for the BP volume on statistical analysis. The BP volumes were smaller than those described in the RTOG atlas paper, with a mean volume of 20.8cc (range 11–40.7 cc) compared with 33±4cc (25.1–39.4cc). The average values of mean dose, maximum dose, V60Gy, V66Gy and V70Gy for patients treated with conventional radiotherapy and IMRT were 42.2Gy versus 44.8Gy, 64.5Gy versus 68.5Gy, 6.1% versus 7.6%, 2.9% versus 2.4% and 0.6% versus 0.3%, respectively. This is the first independent external evaluation of the published protocol. We have identified several issues, including significant interobserver variation. Although radiation oncologists should contour BPs to avoid dose dumping, especially when using IMRT, the RTOG atlas should be used with caution. Because BPs are largely radiologically occult on CT, we propose the term brachial-plexus regions (BPRs) to represent regions where BPs are likely to be present. Consequently, BPRs should in principle be contoured generously.

  17. Facebook Groups as a Powerful and Dynamic Tool in Medical Education: Mixed-Method Study.

    Science.gov (United States)

    Nicolai, Leo; Schmidbauer, Moritz; Gradel, Maximilian; Ferch, Sabine; Antón, Sofía; Hoppe, Boj; Pander, Tanja; von der Borch, Philip; Pinilla, Severin; Fischer, Martin; Dimitriadis, Konstantinos

    2017-12-22

    100% (13/13), and the number of comments per post ranged from 8.4 to 13.7 compared with the average overall reply rate of 68.69% (1167/1699) and 3.9 comments per post. User typology revealed social media drivers (>30 posts per semester) as engines of group function, frequent users (11-30 posts), and a majority of average users acting rather as consumers or lurkers (1-10 posts). For the moment, the medical faculty has no active involvement in these groups and therefore no influence on accuracy of information, professionalism, and ethical issues. Nevertheless, faculty could in the future benefit by extracting relevant information, identifying common problems, and understanding semester-related dynamics. ©Leo Nicolai, Moritz Schmidbauer, Maximilian Gradel, Sabine Ferch, Sofía Antón, Boj Hoppe, Tanja Pander, Philip von der Borch, Severin Pinilla, Martin Fischer, Konstantinos Dimitriadis. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 22.12.2017.

  18. Application of Lie group analysis in geophysical fluid dynamics

    CERN Document Server

    Ibragimov, Ranis

    2011-01-01

    This is the first monograph dealing with the applications of the Lie group analysis to the modeling equations governing internal wave propagation in the deep ocean. A new approach to describe the nonlinear interactions of internal waves in the ocean is presented. While the central idea of the book is to investigate oceanic internal waves through the prism of Lie group analysis, it is also shown for the first time that internal wave beams, representing exact solutions to the equation of motion of stratified fluid, can be found by solving the given model as invariant solutions of nonlinear equat

  19. Group Dynamics and Decision Making: Backcountry Recreationists in Avalanche Terrain

    Science.gov (United States)

    Bright, Leslie Shay

    2010-01-01

    The purpose of this study was to describe and determine the prevalence of decision-making characteristics of recreational backcountry groups when making a decision of where to travel and ride in avalanche terrain from the perspective of individuals. Decision-making characteristics encompassed communication, decision-making processes, leadership,…

  20. GPP Webinar: Solar Utilization in Higher Education Networking & Information Sharing Group: Financing Issues Discussion

    Science.gov (United States)

    This presentation from a Solar Utilization in Higher Education Networking and Information webinar covers financing and project economics issues related to solar project development in the higher education sector.

  1. Electronic [Re]Constitution of Groups: Group Dynamics from Face-to-Face to an Online Setting

    Science.gov (United States)

    Clouder, Lynn; Dalley, Jayne; Hargreaves, Julian; Parkes, Sally; Sellars, Julie; Toms, Jane

    2006-01-01

    The authors work as online tutors for a BSc (Hons) physiotherapy programme at Coventry University in the United Kingdom. This paper represents a stage in our developing understanding, over a 3 year period, of the impact of group dynamics on online interaction among physiotherapy students engaged in sharing with their peers their first experiences…

  2. Dynamics, control and sensor issues pertinent to robotic hands for the EVA retriever system

    Science.gov (United States)

    Mclauchlan, Robert A.

    1987-01-01

    Basic dynamics, sensor, control, and related artificial intelligence issues pertinent to smart robotic hands for the Extra Vehicular Activity (EVA) Retriever system are summarized and discussed. These smart hands are to be used as end effectors on arms attached to manned maneuvering units (MMU). The Retriever robotic systems comprised of MMU, arm and smart hands, are being developed to aid crewmen in the performance of routine EVA tasks including tool and object retrieval. The ultimate goal is to enhance the effectiveness of EVA crewmen.

  3. Addressing group dynamics in a brief motivational intervention for college student drinkers.

    Science.gov (United States)

    Faris, Alexander S; Brown, Janice M

    2003-01-01

    Previous research indicates that brief motivational interventions for college student drinkers may be less effective in group settings than individual settings. Social psychological theories about counterproductive group dynamics may partially explain this finding. The present study examined potential problems with group motivational interventions by comparing outcomes from a standard group motivational intervention (SGMI; n = 25), an enhanced group motivational intervention (EGMI; n = 27) designed to suppress counterproductive processes, and a no intervention control (n = 23). SGMI and EGMI participants reported disruptive group dynamics as evidenced by low elaboration likelihood, production blocking, and social loafing, though the level of disturbance was significantly lower for EGMI individuals (p = .001). Despite counteracting group dynamics in the EGMI condition, participants in the two interventions were statistically similar in post-intervention problem recognition and future drinking intentions. The results raise concerns over implementing individually-based interventions in group settings without making necessary adjustments.

  4. Preface: Special issue featuring papers from the International Conference on Nonequilibrium Carrier Dynamics in Semiconductors

    Science.gov (United States)

    Reggiani, L.; Bordone, P.; Brunetti, R.

    2004-02-01

    The International Conference on Nonequilibrium Carrier Dynamics in Semiconductors (HCIS-13) celebrates 30 years since it first took place in Modena. Nonequilibrium dynamics of charge carriers, pioneered by the hot-electron concept, is an important issue for understanding electro-optic transport properties in semiconductor materials and structures. In these 30 years several topics have matured, and new ones have emerged thus fertilizing the field with a variety of physical problems and new ideas. The history of the conference is summarized in the opening paper `30 years of HCIS'. The future of the conference seems secure considering the continued lively interest of the participants. The conference addressed eleven major topics which constitute the backbone of the proceedings and are summarized as follows: carrier transport in low dimensional and nanostructure systems, nonequilibrium carriers in superlattices and devices, small devices and related phenomena, carrier dynamics and fluctuations, carrier quantum dynamics, coherent/incoherent carrier dynamics of optical excitations and ultra-fast optical phenomena, nonlinear optical effects, transport in organic matter, semiconductor-based spintronics, coherent dynamics in solid state systems for quantum processing and communication, novel materials and devices. Nanometric space scale and femtosecond time scale represent the ultimate domains of theoretical, experimental and practical interest. Traditional fields such as bulk properties, quantum transport, fluctuations and chaotic phenomena, etc, have received thorough and continuous attention. Emerging fields from previous conferences, such as quantum processing and communication, have been better assessed. New fields, such as spintronics and electron transport in organic matter, have appeared for the first time. One plenary talk, 11 invited talks, 230 submitted abstracts covering all these topics constituted a single-session conference. Following scientific selection

  5. Focused Group Discussion of urban ASHA workers regarding their workrelated issues

    Directory of Open Access Journals (Sweden)

    Mansi M Brahmbhatt

    2017-06-01

    Full Text Available Background: Urban ASHA workers bridge the gap between the Urban Health system and urban poor to provide accessible, affordable, accountable, reliable & effective primary health care.  Amis & Objectives: To identify work related problems faced by urban ASHA workers and to seek suggestions for their work-related issues. Settings and Design: FGD of Urban ASHA workers posted at Urban Health Centres of Ahmedabad. Methods and Material: Random sampling was used to select two UHCs and 8 Urban ASHA workers from both the UHCs for conducting FGDs. Statistical analysis used: interview transcribing. Results: Service gave them satisfaction, Salary did not!!! Some of the other important issues related to their work include transportation, cooperation from community, environmental issues & extended working hours. Conclusions: The problems identified and suggestions received needs to be taken seriously, addressed promptly and timely to improve service delivery.

  6. Hospital Patient Room Design: The Issues Facing 23 Occupational Groups Who Work in Medical/Surgical Patient Rooms.

    Science.gov (United States)

    Lavender, Steven A; Sommerich, Carolyn M; Patterson, Emily S; Sanders, Elizabeth B-N; Evans, Kevin D; Park, Sanghyun; Umar, Radin Zaid Radin; Li, Jing

    2015-01-01

    The aim of this study was to learn from a wide range of hospital staff members about how the design of the patient room in which they work adversely affects their ergonomics or hinders their job performance. In addition to providing a healing space for patients, hospital patient rooms need to serve as functional workplaces for the people who provide clinical care, to clean, or to maintain room functions. Therefore, from a design perspective, it is important to understand the needs of all the users of hospital patient rooms with regard to room design. One hundred forty-seven people, representing 23 different occupational stakeholder groups, participated in either focus groups or interviews in which they were asked to identify room design issues that affect the performance of their work tasks. Key issues shared across multiple stakeholder groups included an inability to have eye contact with the patient when entering the room, inadequate space around the bed for the equipment used by stakeholders, the physical demands experienced as stakeholders move furnishings to accomplish their activities or access equipment, and a lack of available horizontal surfaces. Unique issues were also identified for a number of stakeholder groups. There are a number of issues that should be addressed in the next generation of hospital patient rooms, or when refurbishing existing facilities, so that all occupational stakeholder groups can work effectively, efficiently, and without undue physical stress. © The Author(s) 2015.

  7. Modeling Group Perceptions Using Stochastic Simulation: Scaling Issues in the Multiplicative AHP

    DEFF Research Database (Denmark)

    Barfod, Michael Bruhn; van den Honert, Robin; Salling, Kim Bang

    2016-01-01

    This paper proposes a new decision support approach for applying stochastic simulation to the multiplicative analytic hierarchy process (AHP) in order to deal with issues concerning the scale parameter. The paper suggests a new approach that captures the influence from the scale parameter by maki...

  8. Introduction to the special issue : "Cognitive perspectives on group decision and negotiation"

    NARCIS (Netherlands)

    Kolfschoten, G.L.; Reinig, B.A.

    2013-01-01

    Many organizations today rely heavily on their knowledge assets and engage in collaboration to leverage those assets.Managers and decision makers increasingly are forced to forge strategy, negotiate, and make decisions based on a vast amount of complex and dynamic information and expertise.

  9. A Multi-layer Dynamic Model for Coordination Based Group Decision Making in Water Resource Allocation and Scheduling

    Science.gov (United States)

    Huang, Wei; Zhang, Xingnan; Li, Chenming; Wang, Jianying

    Management of group decision-making is an important issue in water source management development. In order to overcome the defects in lacking of effective communication and cooperation in the existing decision-making models, this paper proposes a multi-layer dynamic model for coordination in water resource allocation and scheduling based group decision making. By introducing the scheme-recognized cooperative satisfaction index and scheme-adjusted rationality index, the proposed model can solve the problem of poor convergence of multi-round decision-making process in water resource allocation and scheduling. Furthermore, the problem about coordination of limited resources-based group decision-making process can be solved based on the effectiveness of distance-based group of conflict resolution. The simulation results show that the proposed model has better convergence than the existing models.

  10. Understanding the Influence of Organizational Culture and Group Dynamics on Organizational Change and Learning

    Science.gov (United States)

    Lucas, Colleen; Kline, Theresa

    2008-01-01

    Purpose: The purpose of this study is to investigate the relationship between organizational culture, group dynamics, and organizational learning in the context of organizational change. Design/methodology/approach: A case study was used to examine cultural and group level factors that potentially influence groups' learning in the context of…

  11. Consensus statement on transcultural issues in depression and anxiety from the International Consensus Group on Depression and Anxiety.

    Science.gov (United States)

    Ballenger, J C; Davidson, J R; Lecrubier, Y; Nutt, D J; Kirmayer, L J; Lépine, J P; Lin, K M; Tajima, O; Ono, Y

    2001-01-01

    To provide primary care physicians with a better understanding of transcultural issues in depression and anxiety. The 4 members of the International Consensus Group on Depression and Anxiety were James C. Ballenger (chair), Jonathan R. T. Davidson, Yves Lecrubier, and David J. Nutt. Five faculty invited by the chair also participated: Laurence J. Kirmayer, Jean-Pierre Lepine, Keh-Ming Lin, Osamu Tajima, and Yutaka Ono. The consensus statement is based on the 5 review articles that are published in this supplement and the scientific literature relevant to the issues reviewed in these articles. Group meetings were held over a 2-day period. On day 1, the group discussed the review articles, and the chair identified key issues for further debate. On day 2, the group discussed these issues to arrive at a consensus view. After the group meetings, the consensus statement was drafted by the chair and approved by all attendees. The consensus statement underlines the prevalence of depression and anxiety disorders across all cultures and nations while recognizing that cultural differences exist in symptom presentation and prevalence estimates. In all countries, the recognition of depression by clinicians in the primary care setting is low (generally less than 50%), and the consensus group recommends a 2-step process to aid the recognition and diagnosis of depression. In line with the low recognition of depression and anxiety disorders is the finding that only a small proportion of patients with depression or anxiety are receiving appropriate treatments for their condition. Biological diversity across ethnic groups may account for the differential sensitivity of some groups to psychotropic medication, but this area requires further investigation.

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

    Science.gov (United States)

    Simonneaux, Laurence; Chouchane, Habib

    2011-01-01

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

  13. Mindfulness-Based Group Approach for Undergraduate Students with Disordered Eating or Body Image Issues: A Case Study

    Directory of Open Access Journals (Sweden)

    Olivia Stumpf

    2017-11-01

    Conclusions: A mindfulness-based group approach to treatment of disordered eating or body image issues shows promise for improving the quality of life for college-aged students. Undergraduate institutions have the advantage of using social interaction to facilitate healthy behavioral change. Future research with larger and more diverse samples is suggested, and implications regarding practice and education are also discussed.

  14. Women's experiences of participation in a feminist group for women with complex mental health issues.

    Science.gov (United States)

    Clements Eaton, Emma Catherine; Cox, Rachel

    2015-01-01

    A sample of women (n = 5) participated in a qualitative service evaluation concerning an open-ended, therapeutic group for women only. Data analysis followed suggestions by Halcomb and Davidson (2006). Main themes derived from the evaluation included: 'Groups are different from individual work', 'Belonging/ not being alone', 'Performance in the group', 'The group as a safety net', 'Life improvements and hope for the future' and 'The extent of emotional despair felt'. In this paper, several sub-themes within the main themes and relevant theories and implications for theory and service provision are discussed.

  15. Scheduling with Group Dynamics: a Multi-Robot Task Allocation Algorithm based on Vacancy Chains

    National Research Council Canada - National Science Library

    Dahl, Torbjorn S; Mataric, Maja J; Sukhatme, Gaurav S

    2002-01-01

    .... We present a multi-robot task allocation algorithm that is sensitive to group dynamics. Our algorithm is based on vacancy chains, a resource distribution process common in human and animal societies...

  16. Group Counseling in the Schools: Legal, Ethical, and Treatment Issues in School Practice

    Science.gov (United States)

    Crespi, Tony D.

    2009-01-01

    School psychologists are interested in providing effective and efficient direct services to children. With a wide spectrum of psychological problems impacting children, group counseling represents one viable and valuable intervention. Given the complexity of group counseling, many schools and school psychologists are interested in legal and…

  17. COSTANZA, 1-D 2 Group Space-Dependent Reactor Dynamics of Spatial Reactor with 1 Group Delayed Neutrons

    International Nuclear Information System (INIS)

    Agazzi, A.; Gavazzi, C.; Vincenti, E.; Monterosso, R.

    1964-01-01

    1 - Nature of physical problem solved: The programme studies the spatial dynamics of reactor TESI, in the two group and one space dimension approximation. Only one group of delayed neutrons is considered. The programme simulates the vertical movement of the control rods according to any given movement law. The programme calculates the evolution of the fluxes and temperature and precursor concentration in space and time during the power excursion. 2 - Restrictions on the complexity of the problem: The maximum number of lattice points is 100

  18. Introduction to focus issue: intrinsic and designed computation: information processing in dynamical systems--beyond the digital hegemony.

    Science.gov (United States)

    Crutchfield, James P; Ditto, William L; Sinha, Sudeshna

    2010-09-01

    How dynamical systems store and process information is a fundamental question that touches a remarkably wide set of contemporary issues: from the breakdown of Moore's scaling laws--that predicted the inexorable improvement in digital circuitry--to basic philosophical problems of pattern in the natural world. It is a question that also returns one to the earliest days of the foundations of dynamical systems theory, probability theory, mathematical logic, communication theory, and theoretical computer science. We introduce the broad and rather eclectic set of articles in this Focus Issue that highlights a range of current challenges in computing and dynamical systems.

  19. Group dynamics in a long-term blind endeavor on Earth: An analog for space missions (Lewis & Clark Expedition group dynamic analysis)

    Science.gov (United States)

    Allner, M.; Rygalov, V.

    2008-12-01

    suggested distinguishable mission phase model, the Lewis and Clark Expedition will be analyzed for similarities to these space findings. Factors of consideration in support of this analysis involve an understanding of the leadership qualities of Lewis and Clark (and relations established and maintained with one another), the selection and diversity of their crew, and the group dynamics that were developed and maintained so carefully during the expedition. With this knowledge and understanding one can gain enormous insights useful in the planning and preparation for future long-duration space exploratory missions with high level of autonomy, mobility, minimal primary life support supply and high dependence on material re-circulation and In-Situ Resource Utilization approach.

  20. Introduction to Focus Issue: Rhythms and Dynamic Transitions in Neurological Disease: Modeling, Computation, and Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Kaper, Tasso J., E-mail: tasso@bu.edu; Kramer, Mark A., E-mail: mak@bu.edu [Department of Mathematics and Statistics, Boston University, Boston, Massachusetts 02215 (United States); Rotstein, Horacio G., E-mail: horacio@njit.edu [Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey 07102 (United States)

    2013-12-15

    Rhythmic neuronal oscillations across a broad range of frequencies, as well as spatiotemporal phenomena, such as waves and bumps, have been observed in various areas of the brain and proposed as critical to brain function. While there is a long and distinguished history of studying rhythms in nerve cells and neuronal networks in healthy organisms, the association and analysis of rhythms to diseases are more recent developments. Indeed, it is now thought that certain aspects of diseases of the nervous system, such as epilepsy, schizophrenia, Parkinson's, and sleep disorders, are associated with transitions or disruptions of neurological rhythms. This focus issue brings together articles presenting modeling, computational, analytical, and experimental perspectives about rhythms and dynamic transitions between them that are associated to various diseases.

  1. Surface Modeling, Grid Generation, and Related Issues in Computational Fluid Dynamic (CFD) Solutions

    Science.gov (United States)

    Choo, Yung K. (Compiler)

    1995-01-01

    The NASA Steering Committee for Surface Modeling and Grid Generation (SMAGG) sponsored a workshop on surface modeling, grid generation, and related issues in Computational Fluid Dynamics (CFD) solutions at Lewis Research Center, Cleveland, Ohio, May 9-11, 1995. The workshop provided a forum to identify industry needs, strengths, and weaknesses of the five grid technologies (patched structured, overset structured, Cartesian, unstructured, and hybrid), and to exchange thoughts about where each technology will be in 2 to 5 years. The workshop also provided opportunities for engineers and scientists to present new methods, approaches, and applications in SMAGG for CFD. This Conference Publication (CP) consists of papers on industry overview, NASA overview, five grid technologies, new methods/ approaches/applications, and software systems.

  2. Introduction to Focus Issue: Rhythms and Dynamic Transitions in Neurological Disease: Modeling, Computation, and Experiment

    International Nuclear Information System (INIS)

    Kaper, Tasso J.; Kramer, Mark A.; Rotstein, Horacio G.

    2013-01-01

    Rhythmic neuronal oscillations across a broad range of frequencies, as well as spatiotemporal phenomena, such as waves and bumps, have been observed in various areas of the brain and proposed as critical to brain function. While there is a long and distinguished history of studying rhythms in nerve cells and neuronal networks in healthy organisms, the association and analysis of rhythms to diseases are more recent developments. Indeed, it is now thought that certain aspects of diseases of the nervous system, such as epilepsy, schizophrenia, Parkinson's, and sleep disorders, are associated with transitions or disruptions of neurological rhythms. This focus issue brings together articles presenting modeling, computational, analytical, and experimental perspectives about rhythms and dynamic transitions between them that are associated to various diseases

  3. Self-esteem and anxiety: key issues in an abused women's support group.

    Science.gov (United States)

    Trimpey, M L

    1989-01-01

    A support group was organized for women who sought help to cope with physical and emotional abuse from their male partners. Women who have lived through the cycle of violence may experience a stress response that includes fear, depression, anxiety, and low self-esteem. High anxiety can interfere with problem solving and with developing new coping patterns. Low self-esteem can accompany depression and intensify the sense of helplessness and powerlessness abused women feel. A descriptive study was conducted to determine to what extent women in the group experienced high anxiety and low self-esteem. Results indicated that high levels of anxiety and low self-esteem were present in the group. Anxiety reduction strategies and techniques to enhance self-esteem were developed.

  4. Quantum groups, orthogonal polynomials and applications to some dynamical systems; Groupes quantiques, polynomes orthogonaux et applications a quelques systemes dynamiques

    Energy Technology Data Exchange (ETDEWEB)

    Campigotto, C

    1993-12-01

    The first part is concerned with the introduction of quantum groups as an extension of Lie groups. In particular, we study the case of unitary enveloping algebras in dimension 2. We then connect the quantum group formalism to the construction of g CGC recurrent relations. In addition, we construct g-deformed Krawtchouck and Meixner orthogonal polynomials and list their respective main characteristics. The second part deals with some dynamical systems from a classical, a quantum and a gp-analogue point of view. We investigate the Coulomb Kepler system by using the canonical namical systems which contain as special cases some interesting systems for nuclear of atomic physics and for quantum chemistry, such as the Hartmann system, the ring-shaped oscillator, the Smarodinsky-Winternitz system, the Aharonov-Bohen system and the dyania of Dirac and Schroedinger. (author). 291 refs.

  5. 77 FR 66920 - Registration of Claims to Copyright: Group Registration of Serial Issues Filed Electronically

    Science.gov (United States)

    2012-11-08

    ... registered on a single application and for a single fee. The group registration privilege is contingent upon... was limited to basic registrations, i.e., claims in single works, while the capacity to process online... of related serials. Revisions to the electronic registration system will upgrade the capacity of the...

  6. Gender Variant and Transgender Issues in a Professional Development Book Group

    Science.gov (United States)

    Parker, Bruce; Bach, Jacqueline

    2009-01-01

    The idea for a professional development book group emerged from the authors ongoing conversations with colleagues about how teachers can gain the understanding necessary not only to foster and support gender variant and transgender students, but also incorporate these experiences into their curriculum in a meaningful way. In this article, the…

  7. KEY ISSUES FOR THE ASSESSMENT OF THE ALLERGENIC POTENTIAL OF GENETICALLY MODIFIED FOODS: BREAKOUT GROUP REPORTS

    Science.gov (United States)

    AbstractOn the final afternoon of the Workshop, Assessment of the Allergenic Potential of Genetically Modified Foods, speakers and participants met in breakout groups to discuss specific questions in the areas of 1) Use of Human Clinical Data; 2) Animal Models to Assess Food ...

  8. Building consensus in strategic decision-making : system dynamics as a group support system

    NARCIS (Netherlands)

    Vennix, J.A.M.

    1995-01-01

    System dynamics was originally founded as a method for modeling and simulating the behavior of industrial systems. In recent years it is increasingly employed as a Group Support System for strategic decision-making groups. The model is constructed in direct interaction with a management team, and

  9. Group Dynamics and Individual Roles: A Differentiated Approach to Social-Emotional Learning

    Science.gov (United States)

    Dugas, Daryl

    2017-01-01

    Differentiated instruction is a set of strategies to help teachers meet each child where he or she is in order to improve students' engagement, lead them to do their best work, and maximize their success. This article describes a differentiated classroom management approach based in group dynamics which focuses on the development of group norms…

  10. A generalized Wigner function for quantum systems with the SU(2) dynamical symmetry group

    International Nuclear Information System (INIS)

    Klimov, A B; Romero, J L

    2008-01-01

    We introduce a Wigner-like quasidistribution function to describe quantum systems with the SU(2) dynamic symmetry group. This function is defined in a three-dimensional group manifold and can be used to represent the states defined in several SU(2) invariant subspaces. The explicit differential Moyal-like form of the star product is found and analyzed in the semiclassical limit

  11. Electricity company managers' views of environmental issues: Implications for environmental groups and government

    International Nuclear Information System (INIS)

    Fischhoff, Maya E.

    2007-01-01

    The electricity industry's environmental impacts are a matter of acute interest to many outsiders, including government and environmental groups-and they have sought to affect those impacts through regulations, public pressure, and technical assistance. These approaches reflect outsiders' intuitive theories regarding the industry's goals, practices, and capabilities. The research reported here provides a systematic insiders' view on these processes, based on in-depth interviews with 70 middle managers in two electricity companies heavily reliant on coal. It finds managers sincerely committed to environmental action, but often frustrated by confusing regulatory requirements, perceived costs, and other challenges. It identifies ways of enabling middle managers to act on their commitment, with lessons relevant for outside groups and those within companies seeking to effect change

  12. Building consensus in strategic decision-making : system dynamics as a group support system

    OpenAIRE

    Vennix, J.A.M.

    1995-01-01

    System dynamics was originally founded as a method for modeling and simulating the behavior of industrial systems. In recent years it is increasingly employed as a Group Support System for strategic decision-making groups. The model is constructed in direct interaction with a management team, and the procedure is generally referred to as group model-building. The model can be conceptual (qualitative) or a full-blown (quantitative) computer simulation model. In this article, a case is describe...

  13. Caregiver issues and AIDS orphans: perspectives from a social worker focus group.

    Science.gov (United States)

    Paige, C Y; Johnson, M S

    1997-10-01

    This study examines social workers' perceptions of the needs of families coping with acquired immunodeficiency syndrome (AIDS). This research investigates the problems of family caregivers of children orphaned by human immunodeficiency virus (HIV)-related death of their parents. A qualitative semistructured interview format was used in a focus group of 18 social workers. Four questions were designed to assess family needs and resources, as well as to evaluate the social workers' perspectives of governmental policies affecting these families. A list of four problems and two recommendations for change evolved from the focus group. Inadequate finances to house and care for the children was the primary cause for distress in these families. The major governmental policy that hindered the social workers' ability to assist families pertained to the low financial entitlement for caregivers who are related to the orphaned child. It was noted that unrelated caregivers receive substantially more money for the care of these children than family caregivers receive. Recommendations were made to change this policy and to develop guardianship laws that facilitate families' abilities to provide care to AIDS orphans. Family caregivers of AIDS orphans are bombarded with great demands and limited resources. This analysis of their situation from the social workers' perspective is a positive step toward the improvement of support services for these families. Further research should include individual qualitative interviews assessing the needs of the caregivers and AIDS orphans.

  14. The walking behaviour of pedestrian social groups and its impact on crowd dynamics.

    Directory of Open Access Journals (Sweden)

    Mehdi Moussaïd

    Full Text Available Human crowd motion is mainly driven by self-organized processes based on local interactions among pedestrians. While most studies of crowd behaviour consider only interactions among isolated individuals, it turns out that up to 70% of people in a crowd are actually moving in groups, such as friends, couples, or families walking together. These groups constitute medium-scale aggregated structures and their impact on crowd dynamics is still largely unknown. In this work, we analyze the motion of approximately 1500 pedestrian groups under natural condition, and show that social interactions among group members generate typical group walking patterns that influence crowd dynamics. At low density, group members tend to walk side by side, forming a line perpendicular to the walking direction. As the density increases, however, the linear walking formation is bent forward, turning it into a V-like pattern. These spatial patterns can be well described by a model based on social communication between group members. We show that the V-like walking pattern facilitates social interactions within the group, but reduces the flow because of its "non-aerodynamic" shape. Therefore, when crowd density increases, the group organization results from a trade-off between walking faster and facilitating social exchange. These insights demonstrate that crowd dynamics is not only determined by physical constraints induced by other pedestrians and the environment, but also significantly by communicative, social interactions among individuals.

  15. The maximal kinematical invariance group of fluid dynamics and explosion-implosion duality

    International Nuclear Information System (INIS)

    O'Raifeartaigh, L.; Sreedhar, V.V.

    2001-01-01

    It has recently been found that supernova explosions can be simulated in the laboratory by implosions induced in a plasma by intense lasers. A theoretical explanation is that the inversion transformation, (Σ:t→-1/t, x→x/t), leaves the Euler equations of fluid dynamics, with standard polytropic exponent, invariant. This implies that the kinematical invariance group of the Euler equations is larger than the Galilei group. In this paper we determine, in a systematic manner, the maximal invariance group G of general fluid dynamics and show that it is a semi-direct product G=SL(2, R) three G, where the SL(2, R) group contains the time-translations, dilations, and the inversion Σ, and G is the static (nine-parameter) Galilei group. A subtle aspect of the inclusion of viscosity fields is discussed and it is shown that the Navier-Stokes assumption of constant viscosity breaks the SL(2, R) group to a two-parameter group of time translations and dilations in a tensorial way. The 12-parameter group G is also known to be the maximal invariance group of the free Schroedinger equation. It originates in the free Hamilton-Jacobi equation which is central to both fluid dynamics and the Schroedinger equation

  16. Maintenance grouping strategy for multi-component systems with dynamic contexts

    International Nuclear Information System (INIS)

    Vu, Hai Canh; Do, Phuc; Barros, Anne; Bérenguer, Christophe

    2014-01-01

    This paper presents a dynamic maintenance grouping strategy for multi-component systems with both “positive” and “negative” economic dependencies. Positive dependencies are commonly due to setup cost whereas negative dependencies are related to shutdown cost. Actually, grouping maintenance activities can save part of the setup cost, but can also in the same time increase the shutdown cost. Until now, both types of dependencies have been jointly taken into account only for simple system structures as pure series. The first aim of this paper is to investigate the case of systems with any combination of basic structures (series, parallel or k-out-of n structures). A cost model and a heuristic optimization scheme are proposed since the optimization of maintenance grouping strategy for such multi-component systems leads to a NP-complete problem. Then the second objective is to propose a finite horizon (dynamic) model in order to optimize online the maintenance strategy in the presence of dynamic contexts (change of the environment, the working condition, the production process, etc). A numerical example of a 16-component system is finally introduced to illustrate the use and the advantages of the proposed approach in the maintenance optimization framework. - Highlights: • A dynamic grouping maintenance strategy for complex structure systems is proposed. • Impacts of the system structure on grouping maintenance are investigated. • A grouping approach based on the rolling horizon and GA algorithm is proposed. • Different dynamic contexts and their impacts on grouping maintenance are studied. • The proposed approach can help to update the maintenance planning in dynamic contexts

  17. Bifurcation and complex dynamics of a discrete-time predator-prey system involving group defense

    Directory of Open Access Journals (Sweden)

    S. M. Sohel Rana

    2015-09-01

    Full Text Available In this paper, we investigate the dynamics of a discrete-time predator-prey system involving group defense. The existence and local stability of positive fixed point of the discrete dynamical system is analyzed algebraically. It is shown that the system undergoes a flip bifurcation and a Neimark-Sacker bifurcation in the interior of R+2 by using bifurcation theory. Numerical simulation results not only show the consistence with the theoretical analysis but also display the new and interesting dynamical behaviors, including phase portraits, period-7, 20-orbits, attracting invariant circle, cascade of period-doubling bifurcation from period-20 leading to chaos, quasi-periodic orbits, and sudden disappearance of the chaotic dynamics and attracting chaotic set. The Lyapunov exponents are numerically computed to characterize the complexity of the dynamical behaviors.

  18. Selection of decommissioning strategies: Issues and factors. Report by an expert group

    International Nuclear Information System (INIS)

    2005-11-01

    A comprehensive assessment of possible strategies is the key step in a decommissioning process. It should be initiated at an early stage in a facility's lifecycle and include a number of factors. The IAEA has provided extensive guidance on decommissioning strategy selection, but there are a number of cases - particularly in countries with limited resources, but not limited to them - where the selection is forced and constrained by prevailing factors and conditions. In its role of an international expert committee assisting the IAEA, the Technical Group on Decommissioning (TEGDE) debates and draws conclusions on topics omitted from general guidance. TEGDE members met in Vienna in 2003, 2004 and 2005 to develop the basis for this publication. The views expressed here reflect those of TEGDE and not necessarily those of the IAEA

  19. Non-ladder extended renormalization group analysis of the dynamical chiral symmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, Ken-Ichi; Takagi, Kaoru; Terao, Haruhiko; Tomoyose, Masashi [Kanazawa Univ., Inst. for Theoretical Physics, Kanazawa, Ishikawa (Japan)

    2000-04-01

    The order parameters of dynamical chiral symmetry breaking in QCD, the dynamical mass of quarks and the chiral condensates, are evaluated by numerically solving the non-perturbative renormalization group (NPRG) equations. We employ an approximation scheme beyond 'the ladder', that is, beyond the (improved) ladder Schwinger-Dyson equations. The chiral condensates are enhanced in comparison with the ladder approximation, which is phenomenologically favorable. The gauge dependence of the order parameters is reduced significantly in this scheme. (author)

  20. Non-ladder extended renormalization group analysis of the dynamical chiral symmetry breaking

    International Nuclear Information System (INIS)

    Aoki, Ken-Ichi; Takagi, Kaoru; Terao, Haruhiko; Tomoyose, Masashi

    2000-01-01

    The order parameters of dynamical chiral symmetry breaking in QCD, the dynamical mass of quarks and the chiral condensates, are evaluated by numerically solving the non-perturbative renormalization group (NPRG) equations. We employ an approximation scheme beyond 'the ladder', that is, beyond the (improved) ladder Schwinger-Dyson equations. The chiral condensates are enhanced in comparison with the ladder approximation, which is phenomenologically favorable. The gauge dependence of the order parameters is reduced significantly in this scheme. (author)

  1. Teen Use of Marijuana Edibles: A Focus Group Study of an Emerging Issue.

    Science.gov (United States)

    Friese, Bettina; Slater, Michael D; Annechino, Rachelle; Battle, Robynn S

    2016-06-01

    Recent research indicates that marijuana-infused food product (i.e., edible) use is becoming nearly as common as smoking marijuana where medical marijuana is available. This study explores edible use among teens. We conducted four focus groups in the San Francisco Bay Area with youth, ages 15-17. The focus groups were divided by gender and whether they used marijuana. Some teens mentioned edible use at school. Youth reported that teens consume edibles, primarily to reduce the likelihood of getting caught. Edibles are also attractive to those who do not like to smoke or have concerns about smoking. Both male and female respondents suggested that females are more likely than males to prefer edibles over smoking, one reason for which may be to avoid smelling like marijuana smoke. For some young women, edibles may be a way to avoid publicly presenting themselves as marijuana users. Findings also suggest that youth have access to edibles through multiple sources. Youth reported that they can purchase edibles at school from other students who either make the edibles themselves or are reselling edibles obtained from dispensaries. Both users and non-users were aware of potentially negative consequences related to edible use. Some youth mentioned that they have heard of youth dying from edibles, and several reported being concerned about the high produced by edibles. Female non-users appeared to be more concerned than others about edibles and compared them to drinks that could be spiked with drugs. However, sentiment among some male marijuana users was that if you cannot handle edibles you should not be using them. These findings suggest that strategies to curb access to edibles and use among youth, such as restricting sales of edibles with strong youth appeal and educating youth on the risks of edibles, will need to be developed.

  2. The Dynamics of the Local Group in the Era of Precision Astrometry

    Science.gov (United States)

    Besla, Gurtina; Garavito-Camargo, Nicolas; Patel, Ekta

    2018-06-01

    Our understanding of the dynamics of our Local Group of galaxies has changed dramatically over the past few years owing to significant advancements in astrometry and our theoretical understanding of galaxy structure. New surveys now enable us to map the 3D structure of our Milky Way and the dynamics of tracers of its dark matter distribution, like globular clusters, satellite galaxies and streams, with unprecedented precision. Some results have met with controversy, challenging preconceived notions of the orbital dynamics of key components of the Local Group. I will provide an overview of this evolving picture of our Local Group and outline how we can test the cold dark matter paradigm in the era of Gaia, LSST and JWST.

  3. Renormalization group invariance and optimal QCD renormalization scale-setting: a key issues review

    Science.gov (United States)

    Wu, Xing-Gang; Ma, Yang; Wang, Sheng-Quan; Fu, Hai-Bing; Ma, Hong-Hao; Brodsky, Stanley J.; Mojaza, Matin

    2015-12-01

    A valid prediction for a physical observable from quantum field theory should be independent of the choice of renormalization scheme—this is the primary requirement of renormalization group invariance (RGI). Satisfying scheme invariance is a challenging problem for perturbative QCD (pQCD), since a truncated perturbation series does not automatically satisfy the requirements of the renormalization group. In a previous review, we provided a general introduction to the various scale setting approaches suggested in the literature. As a step forward, in the present review, we present a discussion in depth of two well-established scale-setting methods based on RGI. One is the ‘principle of maximum conformality’ (PMC) in which the terms associated with the β-function are absorbed into the scale of the running coupling at each perturbative order; its predictions are scheme and scale independent at every finite order. The other approach is the ‘principle of minimum sensitivity’ (PMS), which is based on local RGI; the PMS approach determines the optimal renormalization scale by requiring the slope of the approximant of an observable to vanish. In this paper, we present a detailed comparison of the PMC and PMS procedures by analyzing two physical observables R e+e- and Γ(H\\to b\\bar{b}) up to four-loop order in pQCD. At the four-loop level, the PMC and PMS predictions for both observables agree within small errors with those of conventional scale setting assuming a physically-motivated scale, and each prediction shows small scale dependences. However, the convergence of the pQCD series at high orders, behaves quite differently: the PMC displays the best pQCD convergence since it eliminates divergent renormalon terms; in contrast, the convergence of the PMS prediction is questionable, often even worse than the conventional prediction based on an arbitrary guess for the renormalization scale. PMC predictions also have the property that any residual dependence on

  4. Dynamics of infinite-dimensional groups the Ramsey-Dvoretzky-Milman phenomenon

    CERN Document Server

    Pestov, Vladimir

    2006-01-01

    The "infinite-dimensional groups" in the title refer to unitary groups of Hilbert spaces, the infinite symmetric group, groups of homeomorphisms of manifolds, groups of transformations of measure spaces, etc. The book presents an approach to the study of such groups based on ideas from geometric functional analysis and from exploring the interplay between dynamical properties of those groups, combinatorial Ramsey-type theorems, and the phenomenon of concentration of measure. The dynamics of infinite-dimensional groups is very much unlike that of locally compact groups. For instance, every locally compact group acts freely on a suitable compact space (Veech). By contrast, a 1983 result by Gromov and Milman states that whenever the unitary group of a separable Hilbert space continuously acts on a compact space, it has a common fixed point. In the book, this new fast-growing theory is built strictly from well-understood examples up. The book has no close counterpart and is based on recent research articles. At t...

  5. Nonequilibrium dynamical renormalization group: Dynamical crossover from weak to infinite randomness in the transverse-field Ising chain

    Science.gov (United States)

    Heyl, Markus; Vojta, Matthias

    2015-09-01

    In this work we formulate the nonequilibrium dynamical renormalization group (ndRG). The ndRG represents a general renormalization-group scheme for the analytical description of the real-time dynamics of complex quantum many-body systems. In particular, the ndRG incorporates time as an additional scale which turns out to be important for the description of the long-time dynamics. It can be applied to both translational-invariant and disordered systems. As a concrete application, we study the real-time dynamics after a quench between two quantum critical points of different universality classes. We achieve this by switching on weak disorder in a one-dimensional transverse-field Ising model initially prepared at its clean quantum critical point. By comparing to numerically exact simulations for large systems, we show that the ndRG is capable of analytically capturing the full crossover from weak to infinite randomness. We analytically study signatures of localization in both real space and Fock space.

  6. Sex differences in in-group cooperation vary dynamically with competitive conditions and outcomes.

    Science.gov (United States)

    Bailey, Drew H; Winegard, Benjamin; Oxford, Jon; Geary, David C

    2012-03-18

    Men's but not women's investment in a public goods game varied dynamically with the presence or absence of a perceived out-group. Three hundred fifty-four (167 male) young adults participated in multiple iterations of a public goods game under intergroup and individual competition conditions. Participants received feedback about whether their investments in the group were sufficient to earn a bonus to be shared among all in-group members. Results for the first trial confirm previous research in which men's but not women's investments were higher when there was a competing out-group. We extended these findings by showing that men's investment in the in-group varied dynamically by condition depending on the outcome of the previous trial: In the group condition, men, but not women, decreased spending following a win (i.e., earning an in-group bonus). In the individual condition, men, but not women, increased spending following a win. We hypothesize that these patterns reflect a male bias to calibrate their level of in-group investment such that they sacrifice only what is necessary for their group to successfully compete against a rival group.

  7. Sex Differences in In-Group Cooperation Vary Dynamically with Competitive Conditions and Outcomes

    Directory of Open Access Journals (Sweden)

    Drew H. Bailey

    2012-01-01

    Full Text Available Men's but not women's investment in a public goods game varied dynamically with the presence or absence of a perceived out-group. Three hundred fifty-four (167 male young adults participated in multiple iterations of a public goods game under intergroup and individual competition conditions. Participants received feedback about whether their investments in the group were sufficient to earn a bonus to be shared among all in-group members. Results for the first trial confirm previous research in which men's but not women's investments were higher when there was a competing out-group. We extended these findings by showing that men's investment in the in-group varied dynamically by condition depending on the outcome of the previous trial: In the group condition, men, but not women, decreased spending following a win (i.e., earning an in-group bonus. In the individual condition, men, but not women, increased spending following a win. We hypothesize that these patterns reflect a male bias to calibrate their level of in-group investment such that they sacrifice only what is necessary for their group to successfully compete against a rival group.

  8. Dynamic stiffness of pile groups in a multilayered soil. Part 1

    International Nuclear Information System (INIS)

    Ohta, Y.; Hijikata, K.; Kobayashi, Y.

    1989-01-01

    For evaluating the dynamic stiffness of the pile group foundations, forced vibration tests are executed on pile group foundation models. Two types of test models are used, one is a single pile model and the other a four-pile model. Dividing the tests into 4 steps, the forced vibration tests are performed. Step 1 is for the single pile model, and steps 2 to 4 are for the four-pile model. In step 2 and step 3, the gap effects between the foundation bottom and the ground surface are examined. In step 4, the backfill effects are obtained. Based on the test results, the pile group effects, the gap effects and the backfill effects on the dynamic characteristics of the pile group foundations are described in this paper

  9. Brain-to-Brain Synchrony Tracks Real-World Dynamic Group Interactions in the Classroom.

    Science.gov (United States)

    Dikker, Suzanne; Wan, Lu; Davidesco, Ido; Kaggen, Lisa; Oostrik, Matthias; McClintock, James; Rowland, Jess; Michalareas, Georgios; Van Bavel, Jay J; Ding, Mingzhou; Poeppel, David

    2017-05-08

    The human brain has evolved for group living [1]. Yet we know so little about how it supports dynamic group interactions that the study of real-world social exchanges has been dubbed the "dark matter of social neuroscience" [2]. Recently, various studies have begun to approach this question by comparing brain responses of multiple individuals during a variety of (semi-naturalistic) tasks [3-15]. These experiments reveal how stimulus properties [13], individual differences [14], and contextual factors [15] may underpin similarities and differences in neural activity across people. However, most studies to date suffer from various limitations: they often lack direct face-to-face interaction between participants, are typically limited to dyads, do not investigate social dynamics across time, and, crucially, they rarely study social behavior under naturalistic circumstances. Here we extend such experimentation drastically, beyond dyads and beyond laboratory walls, to identify neural markers of group engagement during dynamic real-world group interactions. We used portable electroencephalogram (EEG) to simultaneously record brain activity from a class of 12 high school students over the course of a semester (11 classes) during regular classroom activities (Figures 1A-1C; Supplemental Experimental Procedures, section S1). A novel analysis technique to assess group-based neural coherence demonstrates that the extent to which brain activity is synchronized across students predicts both student class engagement and social dynamics. This suggests that brain-to-brain synchrony is a possible neural marker for dynamic social interactions, likely driven by shared attention mechanisms. This study validates a promising new method to investigate the neuroscience of group interactions in ecologically natural settings. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. Condition-based dynamic maintenance operations planning and grouping. Application to commercial heavy vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Bouvard, K., E-mail: keomany.bouvard@volvo.co [Volvo Technology, 99 route de Lyon, 69806 Saint Priest cedex (France); Laboratoire d' Automatique de Genie Informatique et Signal - FRE3303 - Polytech' Lille, 59655 Villeneuve d' Ascq (France); Artus, S., E-mail: samuel.artus@volvo.co [Volvo Technology, 99 route de Lyon, 69806 Saint Priest cedex (France); Berenguer, C., E-mail: christophe.berenguer@utt.f [Universite de technologie de Troyes - Institut Charles Delaunay and UMR CNRS 6279 - 12, rue Marie Curie, BP2060, 10010 Troyes cedex (France); Cocquempot, V., E-mail: vincent.cocquempot@univ-lille1.f [Laboratoire d' Automatique de Genie Informatique et Signal - FRE3303 - Polytech' Lille, 59655 Villeneuve d' Ascq (France)

    2011-06-15

    This paper aims at presenting a method to optimize the maintenance planning for a commercial heavy vehicle. Such a vehicle may be considered as a multi-components system. Grouping maintenance operations related to each component reduces the global maintenance cost of the system. Classically, the optimization problem is solved using a priori reliability characteristics of components. Two types of methods may be used, i.e. static or dynamic methods. Static methods provide a fixed maintenance planning, whereas dynamic methods redefine the groups of maintenance operations at each decision time. Dynamic procedures can incorporate component information such as component states or detected failures. For deteriorating systems, reliability characteristics of each component may be estimated thanks to deterioration models and may be updated when a degradation measure is available. This additional information on degradation features allows to better follow the real state of each component and to improve the maintenance planning.

  11. Role of Dispersive Fluorous Interaction in the Solvation Dynamics of the Perfluoro Group Containing Molecules.

    Science.gov (United States)

    Mondal, Saptarsi; Chaterjee, Soumit; Halder, Ritaban; Jana, Biman; Singh, Prashant Chandra

    2017-08-17

    Perfluoro group containing molecules possess an important self-aggregation property through the fluorous (F···F) interaction which makes them useful for diverse applications such as medicinal chemistry, separation techniques, polymer technology, and biology. In this article, we have investigated the solvation dynamics of coumarin-153 (C153) and coumarin-6H (C6H) in ethanol (ETH), 2-fluoroethanol (MFE), and 2,2,2-trifluoroethanol (TFE) using the femtosecond upconversion technique and molecular dynamics (MD) simulation to understand the role of fluorous interaction between the solute and solvent molecules in the solvation dynamics of perfluoro group containing molecules. The femtosecond upconversion data show that the time scales of solvation dynamics of C6H in ETH, MFE, and TFE are approximately the same whereas the solvation dynamics of C153 in TFE is slow as compared to that of ETH and MFE. It has also been observed that the time scale of solvation dynamics of C6H in ETH and MFE is higher than that of C153 in the same solvents. MD simulation results show a qualitative agreement with the experimental data in terms of the time scale of the slow components of the solvation for all the systems. The experimental and simulation studies combined lead to the conclusion that the solvation dynamics of C6H in all solvents as well as C153 in ETH and MFE is mostly governed by the charge distribution of ester moieties (C═O and O) of dye molecules whereas the solvation of C153 in TFE is predominantly due to the dispersive fluorous interaction (F···F) between the perfluoro groups of the C153 and solvent molecules.

  12. Exploring Peer Relationships, Friendships and Group Work Dynamics in Higher Education: Applying Social Network Analysis

    Science.gov (United States)

    Mamas, Christoforos

    2018-01-01

    This study primarily applied social network analysis (SNA) to explore the relationship between friendships, peer social interactions and group work dynamics within a higher education undergraduate programme in England. A critical case study design was adopted so as to allow for an in-depth exploration of the students' voice. In doing so, the views…

  13. Density matrix renormalization group with efficient dynamical electron correlation through range separation

    DEFF Research Database (Denmark)

    Hedegård, Erik D.; Knecht, Stefan; Kielberg, Jesper Skau

    2015-01-01

    We present a new hybrid multiconfigurational method based on the concept of range-separation that combines the density matrix renormalization group approach with density functional theory. This new method is designed for the simultaneous description of dynamical and static electroncorrelation...... effects in multiconfigurational electronic structure problems....

  14. Selection-driven extinction dynamics for group II introns in Enterobacteriales.

    Directory of Open Access Journals (Sweden)

    Sébastien Leclercq

    Full Text Available Transposable elements (TEs are one of the major driving forces of genome evolution, raising the question of the long-term dynamics underlying their evolutionary success. Some TEs were proposed to evolve under a pattern of periodic extinctions-recolonizations, in which elements recurrently invade and quickly proliferate within their host genomes, then start to disappear until total extinction. Depending on the model, TE extinction is assumed to be driven by purifying selection against colonized host genomes (Sel-DE model or by saturation of host genomes (Sat-DE model. Bacterial group II introns are suspected to follow an extinction-recolonization model of evolution, but whether they follow Sel-DE or Sat-DE dynamics is not known. Our analysis of almost 200 group II intron copies from 90 sequenced Enterobacteriales genomes confirms their extinction-recolonization dynamics: patchy element distributions among genera and even among strains within genera, acquisition of new group II introns through plasmids or other mobile genetic elements, and evidence for recent proliferations in some genomes. Distributions of recent and past proliferations and of their respective homing sites further provide strong support for the Sel-DE model, suggesting that group II introns are deleterious to their hosts. Overall, our observations emphasize the critical impact of host properties on TE dynamics.

  15. Management factors affecting aggression in dynamic group housing systems with electronic sow feeding - a field trial

    DEFF Research Database (Denmark)

    Sørensen, L S; Bertelsen, D; Jensen, K H

    1999-01-01

    A series of 24-h video studies on four commercial Danish pig herds investigated the behaviour of pregnant sows kept in dynamic groups (72 to 200 sows) with electronic sow feeding (ESF). The herds mainly differed with respect to provision of a layer of unchopped straw as bedding material, the freq...

  16. Dynamic RCS Simulation of a Missile Target Group Based on the High-frequency Asymptotic Method

    Directory of Open Access Journals (Sweden)

    Zhao Tao

    2014-04-01

    Full Text Available To simulate dynamic Radar Cross Section (RCS of missile target group, an efficient RCS prediction approach is proposed based on the high-frequency asymptotic theory. The minimal energy trajectory and coordinate transformation is used to get trajectories of the missile, decoys and roll booster, and establish the dynamic scene for the separate procedure of the target group, and the dynamic RCS including specular reflection, edge diffraction and multi-reflection from the target group are obtained by Physical Optics (PO, Equivalent Edge Currents (EEC and Shooting-and-Bouncing Ray (SBR methods. Compared with the dynamic RCS result with the common interpolation method, the proposed method is consistent with the common method when the targets in the scene are far away from each other and each target is not sheltered by others in the incident direction. When the target group is densely distributed and the shelter effect can not be neglected, the interpolation method is extremely difficult to realize, whereas the proposed method is successful.

  17. A system dynamic modeling approach for evaluating municipal solid waste generation, landfill capacity and related cost management issues

    International Nuclear Information System (INIS)

    Kollikkathara, Naushad; Feng Huan; Yu Danlin

    2010-01-01

    As planning for sustainable municipal solid waste management has to address several inter-connected issues such as landfill capacity, environmental impacts and financial expenditure, it becomes increasingly necessary to understand the dynamic nature of their interactions. A system dynamics approach designed here attempts to address some of these issues by fitting a model framework for Newark urban region in the US, and running a forecast simulation. The dynamic system developed in this study incorporates the complexity of the waste generation and management process to some extent which is achieved through a combination of simpler sub-processes that are linked together to form a whole. The impact of decision options on the generation of waste in the city, on the remaining landfill capacity of the state, and on the economic cost or benefit actualized by different waste processing options are explored through this approach, providing valuable insights into the urban waste-management process.

  18. Dynamics of safety performance and culture: a group model building approach.

    Science.gov (United States)

    Goh, Yang Miang; Love, Peter E D; Stagbouer, Greg; Annesley, Chris

    2012-09-01

    The management of occupational health and safety (OHS) including safety culture interventions is comprised of complex problems that are often hard to scope and define. Due to the dynamic nature and complexity of OHS management, the concept of system dynamics (SD) is used to analyze accident prevention. In this paper, a system dynamics group model building (GMB) approach is used to create a causal loop diagram of the underlying factors influencing the OHS performance of a major drilling and mining contractor in Australia. While the organization has invested considerable resources into OHS their disabling injury frequency rate (DIFR) has not been decreasing. With this in mind, rich individualistic knowledge about the dynamics influencing the DIFR was acquired from experienced employees with operations, health and safety and training background using a GMB workshop. Findings derived from the workshop were used to develop a series of causal loop diagrams that includes a wide range of dynamics that can assist in better understanding the causal influences OHS performance. The causal loop diagram provides a tool for organizations to hypothesize the dynamics influencing effectiveness of OHS management, particularly the impact on DIFR. In addition the paper demonstrates that the SD GMB approach has significant potential in understanding and improving OHS management. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Noninvasive diagnosis of hepatocellular carcinoma: Elaboration on Korean liver cancer study group-National Cancer Center Korea Practice Guidelines compared with other guidelines and remaining issues

    International Nuclear Information System (INIS)

    Yoon, Jeong Hee; Lee, Jeong Min; Park, Joong Won

    2016-01-01

    Hepatocellular carcinoma (HCC) can be diagnosed based on characteristic findings of arterial-phase enhancement and portal/delayed 'washout' in cirrhotic patients. Several countries and major academic societies have proposed varying specific diagnostic criteria for HCC, largely reflecting the variable HCC prevalence in different regions and ethnic groups, as well as different practice patterns. In 2014, a new version of Korean practice guidelines for management of HCC was released by the Korean Liver Cancer Study Group (KLCSG) and the National Cancer Center (NCC). According to the KLCSG-NCC Korea practice guidelines, if the typical hallmark of HCC (i.e., hypervascularity in the arterial phase with washout in the portal or 3 min-delayed phases) is identified in a nodule ≥ 1 cm in diameter on either dynamic CT, dynamic MRI, or MRI using hepatocyte-specific contrast agent in high-risk groups, a diagnosis of HCC is established. In addition, the KLCSG-NCC Korea practice guidelines provide criteria to diagnose HCC for subcentimeter hepatic nodules according to imaging findings and tumor marker, which has not been addressed in other guidelines such as Association for the Study of Liver Diseases and European Association for the Study of the Liver. In this review, we briefly review the new HCC diagnostic criteria endorsed by the 2014 KLCSG-NCC Korea practice guidelines, in comparison with other recent guidelines; we furthermore address several remaining issues in noninvasive diagnosis of HCC, including prerequisite of sonographic demonstration of nodules, discrepancy between transitional phase and delayed phase, and implementation of ancillary features for HCC diagnosis

  20. Noninvasive diagnosis of hepatocellular carcinoma: Elaboration on Korean liver cancer study group-National Cancer Center Korea Practice Guidelines compared with other guidelines and remaining issues

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Jeong Hee; Lee, Jeong Min [Dept. of Radiology, Seoul National University Hospital, Seoul (Korea, Republic of); Park, Joong Won [Center for Liver Cancer, National Cancer Center, Goyang (Korea, Republic of)

    2016-02-15

    Hepatocellular carcinoma (HCC) can be diagnosed based on characteristic findings of arterial-phase enhancement and portal/delayed 'washout' in cirrhotic patients. Several countries and major academic societies have proposed varying specific diagnostic criteria for HCC, largely reflecting the variable HCC prevalence in different regions and ethnic groups, as well as different practice patterns. In 2014, a new version of Korean practice guidelines for management of HCC was released by the Korean Liver Cancer Study Group (KLCSG) and the National Cancer Center (NCC). According to the KLCSG-NCC Korea practice guidelines, if the typical hallmark of HCC (i.e., hypervascularity in the arterial phase with washout in the portal or 3 min-delayed phases) is identified in a nodule ≥ 1 cm in diameter on either dynamic CT, dynamic MRI, or MRI using hepatocyte-specific contrast agent in high-risk groups, a diagnosis of HCC is established. In addition, the KLCSG-NCC Korea practice guidelines provide criteria to diagnose HCC for subcentimeter hepatic nodules according to imaging findings and tumor marker, which has not been addressed in other guidelines such as Association for the Study of Liver Diseases and European Association for the Study of the Liver. In this review, we briefly review the new HCC diagnostic criteria endorsed by the 2014 KLCSG-NCC Korea practice guidelines, in comparison with other recent guidelines; we furthermore address several remaining issues in noninvasive diagnosis of HCC, including prerequisite of sonographic demonstration of nodules, discrepancy between transitional phase and delayed phase, and implementation of ancillary features for HCC diagnosis.

  1. Extending systems thinking in planning and evaluation using group concept mapping and system dynamics to tackle complex problems.

    Science.gov (United States)

    Hassmiller Lich, Kristen; Urban, Jennifer Brown; Frerichs, Leah; Dave, Gaurav

    2017-02-01

    Group concept mapping (GCM) has been successfully employed in program planning and evaluation for over 25 years. The broader set of systems thinking methodologies (of which GCM is one), have only recently found their way into the field. We present an overview of systems thinking emerging from a system dynamics (SD) perspective, and illustrate the potential synergy between GCM and SD. As with GCM, participatory processes are frequently employed when building SD models; however, it can be challenging to engage a large and diverse group of stakeholders in the iterative cycles of divergent thinking and consensus building required, while maintaining a broad perspective on the issue being studied. GCM provides a compelling resource for overcoming this challenge, by richly engaging a diverse set of stakeholders in broad exploration, structuring, and prioritization. SD provides an opportunity to extend GCM findings by embedding constructs in a testable hypothesis (SD model) describing how system structure and changes in constructs affect outcomes over time. SD can be used to simulate the hypothesized dynamics inherent in GCM concept maps. We illustrate the potential of the marriage of these methodologies in a case study of BECOMING, a federally-funded program aimed at strengthening the cross-sector system of care for youth with severe emotional disturbances. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Problem Based Learning as a Shared Musical Journey – Group Dynamics, Communication and Creativity

    Directory of Open Access Journals (Sweden)

    Charlotte Lindvang

    2015-06-01

    Full Text Available The focus of this paper is how we can facilitate problem based learning (PBL more creatively. We take a closer look upon the connection between creative processes and social communication in the PBL group including how difficulties in the social interplay may hinder creativity. The paper draws on group dynamic theory, and points out the importance of building a reflexive milieu in the group. Musical concepts are used to illustrate the communicative and creative aspects of PBL and the paper uses the analogy between improvising together and do a project work together. We also discuss the role of the supervisor in a PBL group process. Further we argue that creativity is rooted deep in our consciousness and connected to our ability to work with a flexible mind. In order to enhance the cohesion as well as the creativity of the group a model of music listening as a concrete intervention tool in PBL processes is proposed.

  3. Technip. Group dynamics and activities. Competitive environment and strategic perspectives. Release - February 2017

    International Nuclear Information System (INIS)

    2017-02-01

    After a synthesis which notably proposes a SWOT analysis of the Technip group, this report proposes a presentation of the Technip Group (general overview, presentation of activities per department, human resources, stock market data, and competitive environment). It gives an overview of the Technip group dynamics and of its activities through a presentation of an environment analysis (world oil demand and production, hydrocarbon prices), a presentation of the group activity (turnover, order takings, performance per activity pole, turnover per geographical area, operational income). It addresses important events and development axes: strategic axes, group restructuring, widening of service provision, R and D investments. Financial data are presented along with the main economic and financial indicators. Important statistical data are provided

  4. Issues in educating health professionals to meet the diverse needs of patients and other service users from ethnic minority groups.

    Science.gov (United States)

    Chevannes, Mel

    2002-08-01

    The main aim of the study was to undertake training needs analysis among a multi-professional group for the purpose of improving care for ethnic minority patients and other service users. Evidence from the literature identifies that some of the explanations advanced for the failure of health professionals to meet the needs of ethnic minorities include lack of understanding of cultural diversities, racism, racial stereotyping, lack of knowledge, exclusivity, and ethnocentrism. While these issues have been addressed in different countries, little work has been carried out to examine these from the perspective of health professionals caring for ethnic minorities. This study is therefore an attempt to find out what health professionals know about caring for patients and other service users from minority ethnic groups and their perception of training needs in this area of work. A pre- and post-training design phase structured the qualitative approach. A purposive sample of individuals working across five health service organizations located in a multi-racial city yielded a multi-professional group of participants. Views of 22 participants were obtained by semi-structured interviews at a pretraining phase. Training needs of health professionals drew on Walklin's (1992) six stages used to structure data collection, data analysis and delivery of training. The post-training phase used questionnaires to evaluate immediate learning that based on a 4-week period of reflection and applied to practice. The questionnaires were complemented by a facilitator-lead focus group. The majority of the participants confirmed that no attention was given in their initial education to the health care needs of minority ethnic groups. Instead, participants engaged in self-initiated learning to improve their knowledge and understanding. The issue of communication was viewed with dissatisfaction and seen as affecting the sufficiency of caring for these patients. All participants rated meeting

  5. Key practical issues in strengthening safety culture. INSAG-15. A report by the International Safety Advisory Group [Russian Edition

    International Nuclear Information System (INIS)

    2015-01-01

    This report describes the essential practical issues to be considered by organizations aiming to strengthen safety culture. It is intended for senior executives, managers and first line supervisors in operating organizations. Although safety culture cannot be directly regulated, it is important that members of regulatory bodies understand how their actions affect the development of attempts to strengthen safety culture and are sympathetic to the need to improve the less formal human related aspects of safety. The report is therefore of relevance to regulators, although not intended primarily for them. The International Nuclear Safety Advisory Group (INSAG) introduced the concept of safety culture in its INSAG-4 report in 1991. Since then, many papers have been written on safety culture, as it relates to organizations and individuals, its improvement and its underpinning prerequisites. Variations in national cultures mean that what constitutes a good approach to enhancing safety culture in one country may not be the best approach in another. However, INSAG seeks to provide pragmatic and practical advice of wide applicability in the principles and issues presented in this report. Nuclear and radiological safety are the prime concerns of this report, but the topics discussed are so general that successful application of the principles should lead to improvements in other important areas, such as industrial safety, environmental performance and, in some respects, wider business performance. This is because many of the attitudes and practices necessary to achieve good performance in nuclear safety, including visible commitment by management, openness, care and thoroughness in completing tasks, good communication and clarity in recognizing major issues and dealing with them as a priority, have wide applicability

  6. Key practical issues in strengthening safety culture. INSAG-15. A report by the International Safety Advisory Group

    International Nuclear Information System (INIS)

    2002-01-01

    This report describes the essential practical issues to be considered by organizations aiming to strengthen safety culture. It is intended for senior executives, managers and first line supervisors in operating organizations. Although safety culture cannot be directly regulated, it is important that members of regulatory bodies understand how their actions affect the development of attempts to strengthen safety culture and are sympathetic to the need to improve the less formal human related aspects of safety. The report is therefore of relevance to regulators, although not intended primarily for them. The International Nuclear Safety Advisory Group (INSAG) introduced the concept of safety culture in its INSAG-4 report in 1991. Since then, many papers have been written on safety culture, as it relates to organizations and individuals, its improvement and its underpinning prerequisites. Variations in national cultures mean that what constitutes a good approach to enhancing safety culture in one country may not be the best approach in another. However, INSAG seeks to provide pragmatic and practical advice of wide applicability in the principles and issues presented in this report. Nuclear and radiological safety are the prime concerns of this report, but the topics discussed are so general that successful application of the principles should lead to improvements in other important areas, such as industrial safety, environmental performance and, in some respects, wider business performance. This is because many of the attitudes and practices necessary to achieve good performance in nuclear safety, including visible commitment by management, openness, care and thoroughness in completing tasks, good communication and clarity in recognizing major issues and dealing with them as a priority, have wide applicability

  7. Dynamic Covalent Chemistry of Carbon Dioxide: Opportunities to Address Environmental Issues.

    Science.gov (United States)

    Septavaux, Jean; Germain, Geoffroy; Leclaire, Julien

    2017-07-18

    Extraction and purification of basic chemicals from complex mixtures has been a persistent issue throughout the development of the chemical sciences. The chemical industry and academic research have grown over the centuries by following a deconstruction-reconstruction approach, reminiscent of the metabolism process. Chemists have designed and optimized extraction, purification, and transformation processes of molecules from natural deposits (fossil fuels, biomass, ores), in order to reassemble them into complex adducts. These highly selective and cost-effective techniques arose from developments in physical chemistry but also in supramolecular chemistry, long before the term was even coined. Thanks to the extremely diverse toolbox currently available to the scientific community, artificial molecular systems of increasing complexity can be built and integrated into high-technology products. If humanity has proven through the ages how gifted it can be at this deconstruction-reconstruction game, which has transformed the natural world to a human-shaped one, it has been confronted for more than a century by a new challenge: the deconstruction and reconstruction from a new type of deposit, the waste resulting from the mass production of disposable manufactured goods. In this Account, we will explore the potential contribution of controlled molecular and supramolecular self-assembly phenomena to the challenge of selective and efficient capture of valuable target molecules from mixtures found in postconsumer waste. While it may appear paradoxical to add more molecular ingredients to an already compositionally complex system in order to address a purification issue, we will compare the selectivity, yield, and cost of such an atypical procedure with traditional physical techniques. In the context of carbon dioxide capture or release, we will specifically focus on the coupling between this reversible covalent fixation of the gas by amines and an additional chemical

  8. Symmetry breaking in the opinion dynamics of a multi-group project organization

    International Nuclear Information System (INIS)

    Zhu Zhen-Tao; Zhou Jing; Chen Xing-Guang; Li Ping

    2012-01-01

    A bounded confidence model of opinion dynamics in multi-group projects is presented in which each group's opinion evolution is driven by two types of forces: (i) the group's cohesive force which tends to restore the opinion back towards the initial status because of its company culture; and (ii) nonlinear coupling forces with other groups which attempt to bring opinions closer due to collaboration willingness. Bifurcation analysis for the case of a two-group project shows a cusp catastrophe phenomenon and three distinctive evolutionary regimes, i.e., a deadlock regime, a convergence regime, and a bifurcation regime in opinion dynamics. The critical value of initial discord between the two groups is derived to discriminate which regime the opinion evolution belongs to. In the case of a three-group project with a symmetric social network, both bifurcation analysis and simulation results demonstrate that if each pair has a high initial discord, instead of symmetrically converging to consensus with the increase of coupling scale as expected by Gabbay's result (Physica A 378 (2007) p. 125 Fig. 5), project organization (PO) may be split into two distinct clusters because of the symmetry breaking phenomenon caused by pitchfork bifurcations, which urges that apart from divergence in participants' interests, nonlinear interaction can also make conflict inevitable in the PO. The effects of two asymmetric level parameters are tested in order to explore the ways of inducing dominant opinion in the whole PO. It is found that the strong influence imposed by a leader group with firm faith on the flexible and open minded follower groups can promote the formation of a positive dominant opinion in the PO

  9. Symmetry breaking in the opinion dynamics of a multi-group project organization

    Science.gov (United States)

    Zhu, Zhen-Tao; Zhou, Jing; Li, Ping; Chen, Xing-Guang

    2012-10-01

    A bounded confidence model of opinion dynamics in multi-group projects is presented in which each group's opinion evolution is driven by two types of forces: (i) the group's cohesive force which tends to restore the opinion back towards the initial status because of its company culture; and (ii) nonlinear coupling forces with other groups which attempt to bring opinions closer due to collaboration willingness. Bifurcation analysis for the case of a two-group project shows a cusp catastrophe phenomenon and three distinctive evolutionary regimes, i.e., a deadlock regime, a convergence regime, and a bifurcation regime in opinion dynamics. The critical value of initial discord between the two groups is derived to discriminate which regime the opinion evolution belongs to. In the case of a three-group project with a symmetric social network, both bifurcation analysis and simulation results demonstrate that if each pair has a high initial discord, instead of symmetrically converging to consensus with the increase of coupling scale as expected by Gabbay's result (Physica A 378 (2007) p. 125 Fig. 5), project organization (PO) may be split into two distinct clusters because of the symmetry breaking phenomenon caused by pitchfork bifurcations, which urges that apart from divergence in participants' interests, nonlinear interaction can also make conflict inevitable in the PO. The effects of two asymmetric level parameters are tested in order to explore the ways of inducing dominant opinion in the whole PO. It is found that the strong influence imposed by a leader group with firm faith on the flexible and open minded follower groups can promote the formation of a positive dominant opinion in the PO.

  10. Protic ammonium carboxylate ionic liquids: insight into structure, dynamics and thermophysical properties by alkyl group functionalization.

    Science.gov (United States)

    Reddy, Th Dhileep N; Mallik, Bhabani S

    2017-04-19

    This study is aimed at characterising the structure, dynamics and thermophysical properties of five alkylammonium carboxylate ionic liquids (ILs) from classical molecular dynamics simulations. The structural features of these ILs were characterised by calculating the site-site radial distribution functions, g(r), spatial distribution functions and structure factors. The structural properties demonstrate that ILs show greater interaction between cations and anions when alkyl chain length increases on the cation or anion. In all ILs, spatial distribution functions show that the anion is close to the acidic hydrogen atoms of the ammonium cation. We determined the role of alkyl group functionalization of the charged entities, cations and anions, in the dynamical behavior and the transport coefficients of this family of ionic liquids. The dynamics of ILs are described by studying the mean square displacement (MSD) of the centres of mass of the ions, diffusion coefficients, ionic conductivities and hydrogen bonds as well as residence dynamics. The diffusion coefficients and ionic conductivity decrease with an increase in the size of the cation or anion. The effect of alkyl chain length on ionic conductivity calculated in this article is consistent with the findings of other experimental studies. Hydrogen bond lifetimes and residence times along with structure factors were also calculated, and are related to alkyl chain length.

  11. The hydrogen atom in a magnetic field. Spectrum from the Coulomb dynamical group approach

    International Nuclear Information System (INIS)

    Delande, D.; Gay, J.C.

    1986-01-01

    Some sample results are presented for the problems of the hydrogen atom in a magnetic field. The energies have been computed for a typical Rydberg situation of atomic physics interest using limited computer facilities. The use of the Coulomb dynamical group allows a complete description of the symmetries and a rational choice of a Sturmian type basis set. Moreover, comparison with Rayleigh-Schrodinger perturbative expansions of the energies is performed. (author)

  12. Dynamical renormalization group approach to transport in ultrarelativistic plasmas: The electrical conductivity in high temperature QED

    International Nuclear Information System (INIS)

    Boyanovsky, Daniel; Vega, Hector J. de; Wang Shangyung

    2003-01-01

    The dc electrical conductivity of an ultrarelativistic QED plasma is studied in real time by implementing the dynamical renormalization group. The conductivity is obtained from the real-time dependence of a dissipative kernel closely related to the retarded photon polarization. Pinch singularities in the imaginary part of the polarization are manifest as secular terms that grow in time in the perturbative expansion of this kernel. The leading secular terms are studied explicitly and it is shown that they are insensitive to the anomalous damping of hard fermions as a result of a cancellation between self-energy and vertex corrections. The resummation of the secular terms via the dynamical renormalization group leads directly to a renormalization group equation in real time, which is the Boltzmann equation for the (gauge invariant) fermion distribution function. A direct correspondence between the perturbative expansion and the linearized Boltzmann equation is established, allowing a direct identification of the self-energy and vertex contributions to the collision term. We obtain a Fokker-Planck equation in momentum space that describes the dynamics of the departure from equilibrium to leading logarithmic order in the coupling. This equation determines that the transport time scale is given by t tr =24 π/e 4 T ln(1/e). The solution of the Fokker-Planck equation approaches asymptotically the steady-state solution as ∼e -t/(4.038...t tr ) . The steady-state solution leads to the conductivity σ=15.698 T/e 2 ln(1/e) to leading logarithmic order. We discuss the contributions beyond leading logarithms as well as beyond the Boltzmann equation. The dynamical renormalization group provides a link between linear response in quantum field theory and kinetic theory

  13. State and group dynamics of world stock market by principal component analysis

    Science.gov (United States)

    Nobi, Ashadun; Lee, Jae Woo

    2016-05-01

    We study the dynamic interactions and structural changes by a principal component analysis (PCA) to cross-correlation coefficients of global financial indices in the years 1998-2012. The variances explained by the first PC increase with time and show a drastic change during the crisis. A sharp change in PC coefficient implies a transition of market state, a situation which occurs frequently in the American and Asian indices. However, the European indices remain stable over time. Using the first two PC coefficients, we identify indices that are similar and more strongly correlated than the others. We observe that the European indices form a robust group over the observation period. The dynamics of the individual indices within the group increase in similarity with time, and the dynamics of indices are more similar during the crises. Furthermore, the group formation of indices changes position in two-dimensional spaces due to crises. Finally, after a financial crisis, the difference of PCs between the European and American indices narrows.

  14. Total. Group dynamics and activities. Competitive environment and strategic perspectives. Release - July 2017

    International Nuclear Information System (INIS)

    2017-07-01

    After a synthesis which notably proposes a SWOT analysis of the Total group, this report proposes a presentation of the Total Group (general overview, presentation of activities, human resources, shareholder structure and stock market data, competitive environment). It gives an overview of the Total group dynamics and of its activities through a presentation of an environment analysis (world oil demand, refining-chemistry activity, hydrocarbon prices), a presentation of the group activity (turnover, turnover per segment, operational income and financial results of competitors). It comments important events and development axes: four strategic orientations, strengthening of the upstream pole, restructuring of refining and chemical activities, widening of the energy provision, consolidation of positions in the marketing and services sector. Financial data are presented along with the main economic and financial indicators. Important statistical data are provided

  15. On the influence of latency estimation on dynamic group communication using overlays

    Science.gov (United States)

    Vik, Knut-Helge; Griwodz, Carsten; Halvorsen, Pål

    2009-01-01

    Distributed interactive applications tend to have stringent latency requirements and some may have high bandwidth demands. Many of them have also very dynamic user groups for which all-to-all communication is needed. In online multiplayer games, for example, such groups are determined through region-of-interest management in the application. We have investigated a variety of group management approaches for overlay networks in earlier work and shown that several useful tree heuristics exist. However, these heuristics require full knowledge of all overlay link latencies. Since this is not scalable, we investigate the effects that latency estimation techqniues have ton the quality of overlay tree constructions. We do this by evaluating one example of our group management approaches in Planetlab and examing how latency estimation techqniues influence their quality. Specifically, we investigate how two well-known latency estimation techniques, Vivaldi and Netvigator, affect the quality of tree building.

  16. Areva. Group dynamics and activities. Competitive environment and strategic perspectives. Release - October 2016

    International Nuclear Information System (INIS)

    2016-10-01

    After a synthesis which notably proposes a SWOT analysis of the Areva group, this report proposes a presentation of the Areva Group (general overview, mining, upstream and downstream poles, shareholder structure and stock market data, competitive environment). It gives an overview of the Areva group dynamics and of its activities through a presentation of an environment analysis (world electric power production, uranium production and consumption, operated nuclear plants in the world), a presentation of the group activity (turnover and order backlog, turnover per segment and per geographical area, operational and net income). It indicates important events and comments development axes: strategic orientations, new partnership with EDF, stronger presence in China, asset disposal, and organisation optimisation. Financial data are presented along with the main economic and financial indicators. Important statistical data are provided

  17. Foreword to the Special Issue on "Dynamic Models in Economics and Finance"

    Science.gov (United States)

    Gardini, Laura; Kubin, Ingrid; Tramontana, Fabio; Wagener, Florian

    2018-05-01

    International workshops on Dynamic Models in Economics and Finance (MDEF) take place every two years in Urbino (Italy); since the inception of the series in 2000, there have been nine editions. The subject has become a central topic for scholars working on economic dynamics. In 2016 the workshop was held under the auspices of University of Urbino "Carlo Bo" , DESP1

  18. A strategic conflict avoidance approach based on cooperative coevolutionary with the dynamic grouping strategy

    Science.gov (United States)

    Guan, Xiangmin; Zhang, Xuejun; Wei, Jian; Hwang, Inseok; Zhu, Yanbo; Cai, Kaiquan

    2016-07-01

    Conflict avoidance plays a crucial role in guaranteeing the safety and efficiency of the air traffic management system. Recently, the strategic conflict avoidance (SCA) problem has attracted more and more attention. Taking into consideration the large-scale flight planning in a global view, SCA can be formulated as a large-scale combinatorial optimisation problem with complex constraints and tight couplings between variables, which is difficult to solve. In this paper, an SCA approach based on the cooperative coevolution algorithm combined with a new decomposition strategy is proposed to prevent the premature convergence and improve the search capability. The flights are divided into several groups using the new grouping strategy, referred to as the dynamic grouping strategy, which takes full advantage of the prior knowledge of the problem to better deal with the tight couplings among flights through maximising the chance of putting flights with conflicts in the same group, compared with existing grouping strategies. Then, a tuned genetic algorithm (GA) is applied to different groups simultaneously to resolve conflicts. Finally, the high-quality solutions are obtained through cooperation between different groups based on cooperative coevolution. Simulation results using real flight data from the China air route network and daily flight plans demonstrate that the proposed algorithm can reduce the number of conflicts and the average delay effectively, outperforming existing approaches including GAs, the memetic algorithm, and the cooperative coevolution algorithms with different well-known grouping strategies.

  19. Deliberations of working group 4: is there a new dynamics of dialogue and decision making?

    International Nuclear Information System (INIS)

    Kotra, J.P.

    2000-01-01

    The context for the working group's discussions was set by two papers: 'Lessons Learnt from the DECI project on different processes for Public Participation and Transparency in Decision making' and 'A New Siting Process in France for a URL in Granite: Lessons Learnt from the recently undertaken Consultation Mission (January-June 2000). As further evidence of change affecting the way waste managers and regulators communicate with their stakeholders, the group heard two presentations of specific case studies of waste disposal programmes encountering and responding to a new dynamic. (Belgium's revised approach to siting a low- and intermediate-level waste facility). Key factors in the new approach adopted by the Belgian government were the clear separation of ethical and technical choices, and the pursuit of partnerships with local municipalities. Many members of the working group were clearly impressed with the extent of trust and reliance placed on the decisions of the participating communities. Next, the group chairperson, discussed recent attempts by the US Nuclear Regulatory Commission to encourage greater public involvement in the development of new regulations for the proposed repository at Yucca Mountain. This was followed by an active and lively discussion among all members of the working group. Frequently the 'new dynamics of dialogue and decision making' were characterised as a shift from the traditional 'decide, announce and defend' approach for which the focus was almost exclusively on technical content, to one of 'engage, interact and co-operate' for which both technical content and quality of process are of comparable import to a constructive outcome. The session culminated with the identification of several possible means through which the FSC (Forum on Stakeholder Confidence) might contribute to and support member programmes as they endeavour to rise to the challenges posed y the new dynamics of dialogue. (author)

  20. BEYOND SOCIAL SKILLS: GROUP DYNAMICS AT SOCIAL SKILLS TRAINING FOR HIGH FUNCTIONING ADOLESCENTS WITH AUTISM SPECTRUM DISORDERS

    Directory of Open Access Journals (Sweden)

    Agnieszka Siedler

    2015-06-01

    Full Text Available The usefulness of group social skills training in Autism Spectrum Disorder therapy has been well established. However, little is known about the group dynamics of this kind of intervention. The current multiple case studies were conducted to demonstrate that, despite of the functioning specifics of participants with ASD, processes associated with the dynamics of the group during group social skills training session may be noticeable. Intervention groups consisted of fifteen adolescents and preadolescents with high functioning Autism Spectrum Disorders aged between 11 to 17 years old divided into three training groups. The social skills training sessions were conducted on a weekly basis. The observation lasted for six months and it included the formation of the group, the period of stability and unexpected changes. After each group session, the therapists filled in a detailed report about the participants’ behavior and interactions between participants. Collected data were carefully analyzed for group dynamic features. It was noticed that adolescents participating in group interventions are susceptible to the influence of the group, take different individual roles and are moderately sensitive to changes in the group structure. The influence of the disorder characteristics on group dynamics was also observed. Although the results show that group dynamics can be observed at a group training for ASD, the need for further structured observation should be emphasized as a current study constituted the first approach to the subject.

  1. Dynamic remodeling of in-group bias during the 2008 presidential election.

    Science.gov (United States)

    Rand, David G; Pfeiffer, Thomas; Dreber, Anna; Sheketoff, Rachel W; Wernerfelt, Nils C; Benkler, Yochai

    2009-04-14

    People often favor members of their own group, while discriminating against members of other groups. Such in-group favoritism has been shown to play an important role in human cooperation. However, in the face of changing conflicts and shifting alliances, it is essential for group identities to be flexible. Using the dictator game from behavioral economics, we demonstrate the remodeling of group identities among supporters of Democratic presidential candidates Barack Obama and Hillary Clinton. After Clinton's concession in June 2008, Democrats were more generous toward supporters of their own preferred candidate than to supporters of the other Democratic candidate. The bias observed in June persisted into August, and disappeared only in early September after the Democratic National Convention. We also observe a strong gender effect, with bias both appearing and subsiding among men only. This experimental study illustrates a dynamic change in bias, tracking the realignment of real world conflict lines and public efforts to reconstitute group identity. The change in salient group identity we describe here likely contributed to the victory of Barack Obama in the 2008 presidential election.

  2. A secure effective dynamic group password-based authenticated key agreement scheme for the integrated EPR information system

    Directory of Open Access Journals (Sweden)

    Vanga Odelu

    2016-01-01

    Full Text Available With the rapid growth of the Internet, a lot of electronic patient records (EPRs have been developed for e-medicine systems. The security and privacy issues of EPRs are important for the patients in order to understand how the hospitals control the use of their personal information, such as name, address, e-mail, medical records, etc. of a particular patient. Recently, Lee et al. proposed a simple group password-based authenticated key agreement protocol for the integrated EPR information system (SGPAKE. However, in this paper, we show that Lee et al.’s protocol is vulnerable to the off-line weak password guessing attack and as a result, their scheme does not provide users’ privacy. To withstand this security weakness found in Lee et al.’s scheme, we aim to propose an effective dynamic group password-based authenticated key exchange scheme for the integrated EPR information system, which retains the original merits of Lee et al.’s scheme. Through the informal and formal security analysis, we show that our scheme provides users’ privacy, perfect forward security and known-key security, and also protects online and offline password guessing attacks. Furthermore, our scheme efficiently supports the dynamic group password-based authenticated key agreement for the integrated EPR information system. In addition, we simulate our scheme for the formal security verification using the widely-accepted AVISPA (Automated Validation of Internet Security Protocols and Applications tool and show that our scheme is secure against passive and active attacks.

  3. Aperiodic dynamics in a deterministic adaptive network model of attitude formation in social groups

    Science.gov (United States)

    Ward, Jonathan A.; Grindrod, Peter

    2014-07-01

    Adaptive network models, in which node states and network topology coevolve, arise naturally in models of social dynamics that incorporate homophily and social influence. Homophily relates the similarity between pairs of nodes' states to their network coupling strength, whilst social influence causes coupled nodes' states to convergence. In this paper we propose a deterministic adaptive network model of attitude formation in social groups that includes these effects, and in which the attitudinal dynamics are represented by an activato-inhibitor process. We illustrate that consensus, corresponding to all nodes adopting the same attitudinal state and being fully connected, may destabilise via Turing instability, giving rise to aperiodic dynamics with sensitive dependence on initial conditions. These aperiodic dynamics correspond to the formation and dissolution of sub-groups that adopt contrasting attitudes. We discuss our findings in the context of cultural polarisation phenomena. Social influence. This reflects the fact that people tend to modify their behaviour and attitudes in response to the opinions of others [22-26]. We model social influence via diffusion: agents adjust their state according to a weighted sum (dictated by the evolving network) of the differences between their state and the states of their neighbours. Homophily. This relates the similarity of individuals' states to their frequency and strength of interaction [27]. Thus in our model, homophily drives the evolution of the weighted ‘social' network. A precise formulation of our model is given in Section 2. Social influence and homophily underpin models of social dynamics [21], which cover a wide range of sociological phenomena, including the diffusion of innovations [28-32], complex contagions [33-36], collective action [37-39], opinion dynamics [19,20,40,10,11,13,15,41,16], the emergence of social norms [42-44], group stability [45], social differentiation [46] and, of particular relevance

  4. Large-scale effects of migration and conflict in pre-agricultural groups: Insights from a dynamic model.

    Directory of Open Access Journals (Sweden)

    Francesco Gargano

    Full Text Available The debate on the causes of conflict in human societies has deep roots. In particular, the extent of conflict in hunter-gatherer groups remains unclear. Some authors suggest that large-scale violence only arose with the spreading of agriculture and the building of complex societies. To shed light on this issue, we developed a model based on operatorial techniques simulating population-resource dynamics within a two-dimensional lattice, with humans and natural resources interacting in each cell of the lattice. The model outcomes under different conditions were compared with recently available demographic data for prehistoric South America. Only under conditions that include migration among cells and conflict was the model able to consistently reproduce the empirical data at a continental scale. We argue that the interplay between resource competition, migration, and conflict drove the population dynamics of South America after the colonization phase and before the introduction of agriculture. The relation between population and resources indeed emerged as a key factor leading to migration and conflict once the carrying capacity of the environment has been reached.

  5. Capturing dynamic processes of change in GROW mutual help groups for mental health.

    Science.gov (United States)

    Finn, Lizzie D; Bishop, Brian J; Sparrow, Neville

    2009-12-01

    The need for a model that can portray dynamic processes of change in mutual help groups for mental health (MHGMHs) is emphasized. A dynamic process model has the potential to capture a more comprehensive understanding of how MHGMHs may assist their members. An investigation into GROW, a mutual help organization for mental health, employed ethnographic, phenomenological and collaborative research methods. The study examined how GROW impacts on psychological well being. Study outcomes aligned with the social ecological paradigm (Maton in Understanding the self-help organization: frameworks and findings. Sage, Thousand Oaks 1994) indicating multifactorial processes of change at and across three levels of analysis: group level, GROW program/community level and individual level. Outcome themes related to life skills acquisition and a change in self-perception in terms of belonging within community and an increased sense of personal value. The GROW findings are used to assist development of a dynamic multi-dimensional process model to explain how MHGMHs may promote positive change.

  6. A study of collective coordinates and dynamical groups in nuclear theory

    International Nuclear Information System (INIS)

    Papadopolos, Z.

    1983-01-01

    Lie-algebraic techniques for the group action on manifolds given as a direct product of coset spaces and group manifolds are developed. The microscopic realisation of the Mass Quadrupole Collective Model (MQC) in the S0(3)xSO(n) and GLsub(+)(3, R)xSO(n) schemes is studied. The problem of the separation of the kinetic energy and the velocity field into a collective and an intrinsic part is analyzed. Different coordinate schemes in phase space for the U(n)-invariant collective motion and the U(3) dynamical group are introduced. In the GL(3,C)xU(n) scheme, the invariant volume element in the new coordinates and a completely orthonormal basis is constructed. (orig.) [de

  7. Dynamic spontaneous breaking of gauge invariance in asymptotically free theories. [Mechanism mass, group renormalization

    Energy Technology Data Exchange (ETDEWEB)

    Ansel' m, A A; D' yakonov, D I [AN SSSR, Leningrad. Inst. Yadernoj Fiziki

    1975-01-01

    The mechanism of dynamic spontaneous breaking of the Coleman-Weinberg gauge invariance is discussed in which scalar fields assume nonzero mean values owing to quantum effects in higher orders of the perturbation theory. Group renormalization methods are used to study scalar electrodynamics and gauge theories similar to that of Yang and Mills; for these gauge theories it is established that by choosing proper constants it is possible to combine the acquisition of a mass by particles, owing to a dynamic violation of symmetry, with the asymptotic freedom of the theory. The symmetry violation is found to be closely related to infrared poles observed in effective charge for asymptotically free theories. The emerging masses of particles automatically cover these poles. It is proved that physical results due to symmetry violation do not depend, at least in the first non-trivial order of the perturbation theory, on the initial gauging of vector fields.

  8. Global dynamics of a novel multi-group model for computer worms

    International Nuclear Information System (INIS)

    Gong Yong-Wang; Song Yu-Rong; Jiang Guo-Ping

    2013-01-01

    In this paper, we study worm dynamics in computer networks composed of many autonomous systems. A novel multi-group SIQR (susceptible-infected-quarantined-removed) model is proposed for computer worms by explicitly considering anti-virus measures and the network infrastructure. Then, the basic reproduction number of worm R 0 is derived and the global dynamics of the model are established. It is shown that if R 0 is less than or equal to 1, the disease-free equilibrium is globally asymptotically stable and the worm dies out eventually, whereas, if R 0 is greater than 1, one unique endemic equilibrium exists and it is globally asymptotically stable, thus the worm persists in the network. Finally, numerical simulations are given to illustrate the theoretical results. (general)

  9. Do Dental Students' Personality Types and Group Dynamics Affect Their Performance in Problem-Based Learning?

    Science.gov (United States)

    Ihm, Jung-Joon; An, So-Youn; Seo, Deog-Gyu

    2017-06-01

    The aim of this study was to determine whether the personality types of dental students and their group dynamics were linked to their problem-based learning (PBL) performance. The Myers-Briggs Type Indicator (MBTI) instrument was used with 263 dental students enrolled in Seoul National University School of Dentistry from 2011 to 2013; the students had participated in PBL in their first year. A four-session PBL setting was designed to analyze how individual personality types and the diversity of their small groups were associated with PBL performance. Overall, the results showed that the personality type of PBL performance that was the most prominent was Judging. As a group became more diverse with its different constituent personality characteristics, there was a tendency for the group to be higher ranked in terms of PBL performance. In particular, the overperforming group was clustered around three major profiles: Extraverted Intuitive Thinking Judging (ENTJ), Introverted Sensing Thinking Judging (ISTJ), and Extraverted Sensing Thinking Judging (ESTJ). Personality analysis would be beneficial for dental faculty members in order for them to understand the extent to which cooperative learning would work smoothly, especially when considering group personalities.

  10. Determination of arterial input function in dynamic susceptibility contrast MRI using group independent component analysis technique

    International Nuclear Information System (INIS)

    Chen, S.; Liu, H.-L.; Yang Yihong; Hsu, Y.-Y.; Chuang, K.-S.

    2006-01-01

    Quantification of cerebral blood flow (CBF) with dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI) requires the determination of the arterial input function (AIF). The segmentation of surrounding tissue by manual selection is error-prone due to the partial volume artifacts. Independent component analysis (ICA) has the advantage in automatically decomposing the signals into interpretable components. Recently group ICA technique has been applied to fMRI study and showed reduced variance caused by motion artifact and noise. In this work, we investigated the feasibility and efficacy of the use of group ICA technique to extract the AIF. Both simulated and in vivo data were analyzed in this study. The simulation data of eight phantoms were generated using randomized lesion locations and time activity curves. The clinical data were obtained from spin-echo EPI MR scans performed in seven normal subjects. Group ICA technique was applied to analyze data through concatenating across seven subjects. The AIFs were calculated from the weighted average of the signals in the region selected by ICA. Preliminary results of this study showed that group ICA technique could not extract accurate AIF information from regions around the vessel. The mismatched location of vessels within the group reduced the benefits of group study

  11. Global dynamics of multi-group SEI animal disease models with indirect transmission

    International Nuclear Information System (INIS)

    Wang, Yi; Cao, Jinde

    2014-01-01

    A challenge to multi-group epidemic models in mathematical epidemiology is the exploration of global dynamics. Here we formulate multi-group SEI animal disease models with indirect transmission via contaminated water. Under biologically motivated assumptions, the basic reproduction number R 0 is derived and established as a sharp threshold that completely determines the global dynamics of the system. In particular, we prove that if R 0 <1, the disease-free equilibrium is globally asymptotically stable, and the disease dies out; whereas if R 0 >1, then the endemic equilibrium is globally asymptotically stable and thus unique, and the disease persists in all groups. Since the weight matrix for weighted digraphs may be reducible, the afore-mentioned approach is not directly applicable to our model. For the proofs we utilize the classical method of Lyapunov, graph-theoretic results developed recently and a new combinatorial identity. Since the multiple transmission pathways may correspond to the real world, the obtained results are of biological significance and possible generalizations of the model are also discussed

  12. Dynamical symmetry breaking of the electroweak interactions and the renormalization group

    International Nuclear Information System (INIS)

    Hill, C.T.

    1990-08-01

    We discuss dynamical symmetry breaking with an emphasis on the renormalization group as the key tool to obtaining reliable predictions. In particular we discuss the mechanism for breaking the electroweak interactions which relies upon the formation of condensates involving the conventional quarks and leptons. Such a scheme indicates that the top quark is heavy, greater than or of order 200 GeV, and gives further predictions for the Higgs boson mass. We also briefly describe recent attempts to incorporate a 4th generation in a more natural scheme. 13 refs., 3 figs., 1 tab

  13. Methyl group dynamics in a glass and its crystalline counterpart by neutron scattering

    CERN Document Server

    Moreno, A J; Colmenero, J; Frick, B

    2002-01-01

    Methyl group dynamics in the same sample of sodium acetate trihydrate in crystalline and glassy states have been investigated by neutron scattering. Measurements have been carried out in the whole temperature range covering the crossover from rotational tunneling to classical hopping. The results in the crystalline sample have been analyzed according to the usual single-particle model, while those in the glass were analyzed in terms of a broad Gaussian distribution of single-particle potentials, with a standard deviation of 205 K. The average barrier in the glass (417 K) takes, within the experimental error, the same value as the unique barrier in the crystal. (orig.)

  14. A summary of the conclusions of generic issue 113: Dynamic qualification and testing of large bore hydraulic snubbers

    International Nuclear Information System (INIS)

    Ware, A.G.; Nitzel, M.E.

    1993-01-01

    The Nuclear Regulatory Commission (NRC) developed Generic Issue 113, Dynamic Qualification and Testing of Large Bore Hydraulic Snubbers (LBHSs), with the objective of evaluating the reliability of LBHSs in operating commercial nuclear power plants. For the purposes of this research, LBHSs were defined as those hydraulic snubbers with rated load capacities ≥50 kips. Relatively high LBHS failure rates were common during the early 1980s; however, industry actions taken during the last several years in response to increased inspection and testing requirements have resulted in lower LBHS failure rates. To address the issue of LBHS adequacy, the NRC developed Generic Issue 113 (GI-113). This paper provides a summary of the important findings of the GI-113 research program and a discussion of the recommendations that were made in NUREG/CR-5416. Fifteen potential improvements in LBHS reliability were identified, covering the areas of design, environmental (including dynamic) qualification, functional testing, visual inspection, and personnel training. Probabilistic risk assessment studies were used to perform a cost/benefit analysis for each. There were five potential improvements in functional testing and visual inspections with low cost/benefit ratios for both existing and future nuclear plants, and an additional six potential improvements that were determined to be cost beneficial only for future plants. Further investigations of the single failure of snubbers that could damage critical components or systems were recommended in NUREG/CR-5416

  15. Tuning of electronic properties and dynamical stability of graphene oxide with different functional groups

    Science.gov (United States)

    Dabhi, Shweta D.; Jha, Prafulla K.

    2017-09-01

    The structural, electronic and vibrational properties of graphene oxide (GO) with varying proportion of epoxy and hydroxyl functional groups have been studied using density functional theory. The functional groups and oxygen density have an obvious influence on the electronic and vibrational properties. The dependence of band gap on associated functional groups and oxygen density shows a possibility of tuning the band gap of graphene by varying the functional groups as well as oxidation level. The absorption of high oxygen content in graphene leads to the gap opening and resulting in a transition from semimetal to semiconductor. Phonon dispersion curves show no imaginary frequency or no softening of any phonon mode throughout the Brillouin zone which confirms the dynamical stability of all considered GO models. Different groups and different oxygen density result into the varying characteristics of phonon modes. The computed results show good agreement with the experimental observations. Our results present interesting possibilities for engineering the electronic properties of graphene and GO and impact the fabrication of new electronics.

  16. Hydrogen bonding analysis of hydroxyl groups in glucose aqueous solutions by a molecular dynamics simulation study

    International Nuclear Information System (INIS)

    Chen, Cong; Li, Wei Zhong; Song, Yong Chen; Weng, Lin Dong; Zhang, Ning

    2012-01-01

    Molecular dynamics simulations have been performed to investigate hydrogen bonding characteristics of hydroxyl groups in glucose aqueous solutions with different concentrations. The hydrogen bonding abilities and strength of different O and H atom types have been calculated and compared. The acceptor/donor efficiencies have been predicted and it has been found that: (1) O2-HO2 and O3-HO3 are more efficient intramolecular hydrogen bonding acceptors than donors; (2) O1-HO1, O4-HO4 and O6-HO6 are more efficient intramolecular hydrogen bonding donors than acceptors; (5) O1-HO1 and O6-HO6 are more efficient intermolecular hydrogen bonding acceptors than donors while hydroxyl groups O2-HO2 and O4-HO4 are more efficient intermolecular hydrogen bonding donors than acceptors. The hydrogen bonding abilities of hydroxyl groups revealed that: (1) the hydrogen bonding ability of OH2-H w is larger than that of hydroxyl groups in glucose; (2) among the hydroxyl groups in glucose, the hydrogen bonding ability of O6-HO6 is the largest and the hydrogen bonding ability of O4-HO4 is the smallest; (3) the intermolecular hydrogen bonding ability of O6-HO6 is the largest; (4) the order for intramolecular hydrogen bonding abilities (from large to small) is O2-HO2, O1-HO1, O3-HO3, O6-HO6 and O4-HO4

  17. Dynamic of consumer groups and response of commodity markets by principal component analysis

    Science.gov (United States)

    Nobi, Ashadun; Alam, Shafiqul; Lee, Jae Woo

    2017-09-01

    This study investigates financial states and group dynamics by applying principal component analysis to the cross-correlation coefficients of the daily returns of commodity futures. The eigenvalues of the cross-correlation matrix in the 6-month timeframe displays similar values during 2010-2011, but decline following 2012. A sharp drop in eigenvalue implies the significant change of the market state. Three commodity sectors, energy, metals and agriculture, are projected into two dimensional spaces consisting of two principal components (PC). We observe that they form three distinct clusters in relation to various sectors. However, commodities with distinct features have intermingled with one another and scattered during severe crises, such as the European sovereign debt crises. We observe the notable change of the position of two dimensional spaces of groups during financial crises. By considering the first principal component (PC1) within the 6-month moving timeframe, we observe that commodities of the same group change states in a similar pattern, and the change of states of one group can be used as a warning for other group.

  18. Systems approach to studying animal sociality: individual position versus group organization in dynamic social network models.

    Directory of Open Access Journals (Sweden)

    Karlo Hock

    2010-12-01

    Full Text Available Social networks can be used to represent group structure as a network of interacting components, and also to quantify both the position of each individual and the global properties of a group. In a series of simulation experiments based on dynamic social networks, we test the prediction that social behaviors that help individuals reach prominence within their social group may conflict with their potential to benefit from their social environment. In addition to cases where individuals were able to benefit from improving both their personal relative importance and group organization, using only simple rules of social affiliation we were able to obtain results in which individuals would face a trade-off between these factors. While selection would favor (or work against social behaviors that concordantly increase (or decrease, respectively fitness at both individual and group level, when these factors conflict with each other the eventual selective pressure would depend on the relative returns individuals get from their social environment and their position within it. The presented results highlight the importance of a systems approach to studying animal sociality, in which the effects of social behaviors should be viewed not only through the benefits that those provide to individuals, but also in terms of how they affect broader social environment and how in turn this is reflected back on an individual's fitness.

  19. A wide-range model of two-group gross sections in the dynamics code HEXTRAN

    International Nuclear Information System (INIS)

    Kaloinen, E.; Peltonen, J.

    2002-01-01

    In dynamic analyses the thermal hydraulic conditions within the reactor core may have a large variation, which sets a special requirement on the modeling of cross sections. The standard model in the dynamics code HEXTRAN is the same as in the static design code HEXBU-3D/MODS. It is based on a linear and second order fitting of two-group cross sections on fuel and moderator temperature, moderator density and boron density. A new, wide-range model of cross sections developed in Fortum Nuclear Services for HEXBU-3D/MOD6 has been included as an option into HEXTRAN. In this model the nodal cross sections are constructed from seven state variables in a polynomial of more than 40 terms. Coefficients of the polynomial are created by a least squares fitting to the results of a large number of fuel assembly calculations. Depending on the choice of state variables for the spectrum calculations, the new cross section model is capable to cover local conditions from cold zero power to boiling at full power. The 5. dynamic benchmark problem of AER is analyzed with the new option and results are compared to calculations with the standard model of cross sections in HEXTRAN (Authors)

  20. Explorations in combining cognitive models of individuals and system dynamics models of groups.

    Energy Technology Data Exchange (ETDEWEB)

    Backus, George A.

    2008-07-01

    This report documents a demonstration model of interacting insurgent leadership, military leadership, government leadership, and societal dynamics under a variety of interventions. The primary focus of the work is the portrayal of a token societal model that responds to leadership activities. The model also includes a linkage between leadership and society that implicitly represents the leadership subordinates as they directly interact with the population. The societal model is meant to demonstrate the efficacy and viability of using System Dynamics (SD) methods to simulate populations and that these can then connect to cognitive models depicting individuals. SD models typically focus on average behavior and thus have limited applicability to describe small groups or individuals. On the other hand, cognitive models readily describe individual behavior but can become cumbersome when used to describe populations. Realistic security situations are invariably a mix of individual and population dynamics. Therefore, the ability to tie SD models to cognitive models provides a critical capability that would be otherwise be unavailable.

  1. Dynamic stiffness and seismic input motion of a group of battered piles

    International Nuclear Information System (INIS)

    Wolf, J.P.

    1979-01-01

    The dynamic stiffness (impedance function) and the corresponding seismic input motion of a group of battered piles, which can be end-bearing and floating, situated in any desired configuration in horizontally stratified soil, are determined. The soil and the piles consist of (frequency-dependent) visco-elastic material with hysteretic damping. The base mat can be rigid or flexible. Any seismic excitation, for which the free-field motion can be calculated, can be specified (body waves, propagating at an arbitrary angle, generalized surface waves). The soil is discretized by toroidal finite elements in conjunction with a Fourier expansion in the circumferential direction. Radiation and hysteretic damping are accounted for. The dynamic-flexibility matrix of the soil is generated, superimposing the basic dynamic-flexibility coefficients calculated by applying sequentially a horizontal and a vertical force at all nodes located on the axis of symmetry. The influence of the soil which is subsequently replaced by piles is taken into consideration. Pile-soil-pile interaction is accounted for in this method. The formulation can also be applied to embedded foundation and buried structures such as tunnels and pipe systems. (Auth.)

  2. Intersection Group Dynamic Subdivision and Coordination at Intraregional Boundaries in Sudden Disaster

    Directory of Open Access Journals (Sweden)

    Ciyun Lin

    2015-01-01

    Full Text Available This paper aims at the traffic flow agglomeration effect characteristics and rapid evacuation requirement in sudden disaster; operation time of intraregional boundaries traffic signal coordination was presented firstly. Then intraregional boundaries intersection group dynamic subdivision and consolidation method based on relative similarity degree and similarity coefficient of adjacent intersections was put forward. As to make the traffic control strategy adapt to traffic condition of different intraregional boundaries intersection groups, this paper proposes an intraregional boundaries traffic signal coordination and optimization technology based on organic computing theory. Finally, this paper uses Delphi 7.0, MapX, and Oracle developing a software package, combined with Paramics V6 Simulator to validate the methods of this paper. The result shows that it can obviously improve disaster affected regional traffic signal control efficiency which reduces average traffic delay by 30–35%, decreases vehicle queue by more than 20% and reduces evacuation time more than 13.06%.

  3. EDF. Group dynamics and activities. Competitive environment and strategic perspectives. Release - October 2017

    International Nuclear Information System (INIS)

    2017-10-01

    After a synthesis, this report proposes a presentation of the EDF Group (general overview, activities, human resources, share-holding structure, stock market data). It gives an overview of the EDF Group dynamics and of its activities: environment analysis (world electric power production, power consumption in France, regulated and spot prices, turnover in France and per area and market segment), performance analysis, and competitive analysis (comparison with the main European energy companies). It analyses the different development axes and discusses main events regarding the consolidation of nuclear activities, investments in renewable energies, withdrawal from coal and fuel, diversification in energy services, and financial consolidation. Financial data are presented along with the main economic and financial indicators. Important statistical data are provided

  4. The dynamics of the Local Group as a probe of dark energy and modified gravity

    Science.gov (United States)

    Carlesi, Edoardo; Mota, David F.; Winther, Hans A.

    2017-04-01

    In this work, we study the dynamics of the Local Group (LG) within the context of cosmological models beyond General Relativity (GR). Using observable kinematic quantities to identify candidate pairs, we build up samples of simulated LG-like objects drawing from f(R), symmetron, Dvali, Gabadadze & Porrati and quintessence N-body simulations together with their Λ cold dark matter (ΛCDM) counterparts featuring the same initial random phase realizations. The variables and intervals used to define LG-like objects are referred to as LG model; different models are used throughout this work and adapted to study their dynamical and kinematic properties. The aim is to determine how well the observed LG dynamics can be reproduced within cosmological theories beyond GR, We compute kinematic properties of samples drawn from alternative theories and ΛCDM and compare them to actual observations of the LG mass, velocity and position. As a consequence of the additional pull, pairwise tangential and radial velocities are enhanced in modified gravity and coupled dark energy with respect to ΛCDM inducing significant changes to the total angular momentum and energy of the LG. For example, in models such as f(R) and the symmetron this increase can be as large as 60 per cent, peaking well outside of the 95 per cent confidence region allowed by the data. This shows how simple considerations about the LG dynamics can lead to clear small-scale observational signatures for alternative scenarios, without the need of expensive high-resolution simulations.

  5. Individual killer whale vocal variation during intra-group behavioral dynamics

    Science.gov (United States)

    Grebner, Dawn M.

    calls discussed in Chapter 6 showed that the higher frequency component (HFC) was always associated with sideband 7 (SB7) of the lower frequency component (LFC). Insight into Northern Resident killer whale intra-group vocal dynamics would aid our understanding of vocal behaviors of many other marine mammal species that rely on vocal exchanges for prey capture, group movement or survival. This is the first study to focus on killer whale vocal content and usage as it pertains to intra-group dynamics for (1) mother and offspring separations and (2) for all individuals prior to joining events, as well as (3) individual usage in a diverging pulsed call. It is also the first time the N04 call has been parsed into subtypes.

  6. Dynamic Group Management Scheme for Sustainable and Secure Information Sensing in IoT

    Directory of Open Access Journals (Sweden)

    Hyungjoo Kim

    2016-10-01

    Full Text Available The services provided to users in the environment associated with the Internet of Things (hereinafter referred to as IoT begin with the information collected from sensors. It is imperative to transmit high-quality sensor data for providing better services. It is also required to collect data only from those authenticated sensors. Moreover, it is imperative to collect high-quality data on a sustainable and continuous basis in order to provide services anytime and anywhere in the IoT environment. Therefore, high-quality, authenticated sensor networks should be constructed. The most prominent routing protocol to enhance the energy consumption efficiency for the sustainable data collection in a sensor network is the LEACH routing protocol. The LEACH routing protocol transmits sensor data by measuring the energy of sensors and allocating sensor groups dynamically. However, these sensor networks have vulnerabilities such as key leakage, eavesdropping, replay attack and relay attack, given the nature of wireless network communication. A large number of security techniques have been studied in order to solve these vulnerabilities. Nonetheless, these studies still cannot support the dynamic sensor group allocation of the LEACH routing protocol. Furthermore, they are not suitable for the sensor nodes whose hardware computing ability and energy resources are limited. Therefore, this paper proposed a group sensor communication protocol that utilizes only the four fundamental arithmetic operations and logical operation for the sensor node authentication and secure data transmission. Through the security analysis, this paper verified that the proposed scheme was secure to the vulnerabilities resulting from the nature of wireless network communication. Moreover, this paper verified through the performance analysis that the proposed scheme could be utilized efficiently.

  7. Computational issues in the analysis of nonlinear two-phase flow dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Rosa, Mauricio A. Pinheiro [Centro Tecnico Aeroespacial (CTA-IEAv), Sao Jose dos Campos, SP (Brazil). Inst. de Estudos Avancados. Div. de Energia Nuclear], e-mail: pinheiro@ieav.cta.br; Podowski, Michael Z. [Rensselaer Polytechnic Institute, New York, NY (United States)

    2001-07-01

    This paper is concerned with the issue of computer simulations of flow-induced instabilities in boiling channels and systems. A computational model is presented for the time-domain analysis of nonlinear oscillations in interconnected parallel boiling channels. The results of model testing and validation are shown. One of the main concerns here has been to show the importance in performing numerical testing regarding the selection of a proper numerical integration method and associated nodalization and time step as well as to demonstrate the convergence of the numerical solution prior to any analysis. (author)

  8. Issues in radioactive waste disposal. Second report of the working group on principles and criteria for radioactive waste disposal

    International Nuclear Information System (INIS)

    1996-10-01

    This report discusses issues related to long time-scale underground disposal of radioactive wastes. The chapters are devoted to the following issues: (1) Post closure issues of underground repositories, e.g., record keeping and markers, public reassurance and prevention of misuse; (2) Optimization of radiation protection by optimizing radioactive waste management, siting analysis, repository design etc.; (3) An interface between nuclear safeguards and radioactive waste management by safeguarding conditioning of spent fuel, during operational phase of repository and post-closure phase of the repository. 31 refs

  9. Calculation of the electrostatic potential of lipid bilayers from molecular dynamics simulations: methodological issues

    DEFF Research Database (Denmark)

    Gurtovenko, Andrey A; Vattulainen, Ilpo

    2009-01-01

    of the electrostatic potential from atomic-scale molecular dynamics simulations of lipid bilayers. We discuss two slightly different forms of Poisson equation that are normally used to calculate the membrane potential: (i) a classical form when the potential and the electric field are chosen to be zero on one...... systems). For symmetric bilayers we demonstrate that both approaches give essentially the same potential profiles, provided that simulations are long enough (a production run of at least 100 ns is required) and that fluctuations of the center of mass of a bilayer are properly accounted for. In contrast...

  10. GPP Webinar: Solar Utilization in Higher Education Networking & Information Sharing Group: RFP, Contract, and Administrative Issues Discussion

    Science.gov (United States)

    This presentation from a Solar Utilization in Higher Education Networking and Information webinar covers contracts, Request for Proposals (RFPs), and administrative issues related to solar project development in the higher education sector.

  11. Extremist Construction of Identity: How Escalating Demands for Legitimacy Shape and Define In-Group and Out-Group Dynamics

    Directory of Open Access Journals (Sweden)

    J.M. Berger

    2017-04-01

    Full Text Available This Research Paper examines how the white supremacist movement Christian Identity emerged from a non-extremist forerunner known as British Israelism. By examining ideological shifts over the course of nearly a century, the paper seeks to identify key pivot points in the movement’s shift toward extremism and explain the process through which extremist ideologues construct and define in-group and out-group identities. Based on these findings, the paper proposes a new framework for analysing and understanding the behaviour and emergence of extremist groups. The proposed framework can be leveraged to design strategic counter-terrorism communications programmes using a linkage-based approach that deconstructs the process of extremist in-group and out-group definition. Future publications will continue this study, seeking to refine the framework and operationalise messaging recommendations.

  12. Engie. Group dynamics and activities. Competitive environment and strategic perspectives. Release - October 2017

    International Nuclear Information System (INIS)

    2017-09-01

    After a synthesis, this report proposes a presentation of the Engie Group (general overview, activities in the different parts of the world, evolution of human resources, share-holding structure, stock market data, high management, competitive environment). It gives an overview of the Engie group dynamics and of its activities through a presentation of an environment analysis (world energy market, European gas and electricity market, gas consumption in France, regulated tariffs and spot prices, temperatures in France, regulatory evolutions), a presentation of the group activity (turnover in France, gas and electricity sales, turnover per area and market segment), a performance analysis (operating income), and a competitive analysis (comparison with the main European energy companies). It analyses the different development axes and discusses main events regarding Engie's strategy, the implementation of a large asset disposal, how Engie gets on the path of renewable energies, and the development of energy services. Financial data are presented along with the main economic and financial indicators. Important statistical data are provided

  13. Impact of weather on dynamics of plant functional groups in an abandoned limestone grassland

    Directory of Open Access Journals (Sweden)

    Zbigniew Dzwonko

    2011-12-01

    Full Text Available We examined to what extend the rate and direction of changes in unmanaged grassland depend on fluctuations in climatic conditions. Vegetation data from permanent plots in a semi-natural grassland in southern Poland collected over 12 years were used. Relations between weather variables, time, and the cover of 41 more frequent species and 14 plant functional groups were analysed. The greatest effect on the dynamics of species and functional groups had precipitation in spring and/or early summer, particularly in the current year. The majority of plant groups were significantly affected also by the temperature in spring and early summer in one of the three previous years. During 12 years, the cover of annuals and biennials, short plants, and plants with small leaves decreased, while the cover of taller plants, plants with larger leaves, and with vegetative spread increased. The analyses suggest that these successional changes were not directly associated with climatic conditions but were affected by them indirectly through interspecific competition. The fluctuations in climatic conditions, chiefly precipitation, had a significant effect on both the composition and the rate of changes in abandoned grassland. The increase in the cover of tall perennial species with broad leaves hindered succession towards woodland despite of the presence of woods in the closed vicinity. It can be expected that during drier periods colonisation of grassland by later successional species could be easier.

  14. Business potentials related to smart grid. Issue paper - working group 5; Denmark. Smart Grid Network; Erhvervspotentialer i Smart Grid. Issue paper, arbejdsgruppe 5

    Energy Technology Data Exchange (ETDEWEB)

    Hauge, B. (Villawatt, Taastrup (Denmark)); Mortensen, E. (DI Energibranchen, Copenhagen (Denmark)); Lyck, L.L. (DONG Energy A/S, Fredericia (Denmark)); Hillingsoee Stubberup, M. (Udenrigsministeriet. Invest in Denmark, Copenhagen (Denmark)); Baadsgaard Trolle, M. (Dansk Energi, Frederiksberg (Denmark)); Lomholt Svensson, N. (Klima- og Energiministeriet, Copenhagen (Denmark)); Roemer Kofod, P. (ABB A/S, Skovlunde); Hauch, R. (IBM A/S, Kgs. Lyngby (Denmark)); Cajus, S. (DI ITEK, Copenhagen (Denmark)); Stroem, S. (Vindmoelleindustrien, Frederiksberg (Denmark))

    2011-07-01

    The Smart Grid Network was established in 2010 by the Danish climate and energy minister tasked with developing recommendations for future actions and initiatives that make it possible to handle up to 50% electricity from wind energy in the power system in 2020. The task of working group 5 provides an immediate assessment of business potential at the sector level based on the recommendations contained in the reports of the working groups 1-4. The working group has only drawn preliminary conclusions regarding business opportunities that may arise as a result of the other network groups' recommendations. In particular three areas, Denmark has at present the potential to strengthen the Danish business potential: 1) System Solutions. The intelligent energy system is more about interaction between different system components than the components themselves. Here Denmark belongs to the world elite, including the extensive use of cogeneration and wind power; 2) Market Solutions. The Nordic electricity trading system ''Nord Pool'' is the most efficient market-based electricity system in the world, and Denmark has thus a good basis for creating market-based solutions for future power systems; 3) Large-scale demonstration environments creates opportunities for companies to test and refine their products, solutions and services. In Denmark, Energinet.dk and utility companies have opened up for companies to use the Danish network for testing solutions to real customers. More foreign players thus regard Denmark as an attractive market to test new technologies, partly because the Danish market is homogeneous and clear, and partly because Denmark in relation to the power system has a robust and well-managed network. Finally, the high share of fluctuating energy production helps to clarify the need for a flexible and intelligent power system. It is this combination of strengths that make Denmark a unique market for international companies to locate their

  15. Intra-Party Dynamics and the Political Transformation of Non-State Armed Groups

    Directory of Open Access Journals (Sweden)

    Véronique Dudouet

    2012-05-01

    Full Text Available Although non-state armed groups are primary stakeholders in contemporary political conflicts, there has been little research into their members’ perspectives on internal factors shaping radicalisation and de-radicalisation. State and international actors often assume that bringing rebel leaders to the negotiating table or “converting” them to peaceful politicians means weakening, splitting, or dismantling militant structures. This paper re-evaluates those assumptions in the light of rebel leaders’ own accounts of internal organisational dynamics before, during, and after political conflicts and peace settlements. Participatory action research with “insider experts” from armed movements in Northern Ireland, Kosovo, Nepal, Aceh, El Salvador, Colombia, and South Africa reveals insiders’ analysis of leadership and organisational dynamics during armed conflict and political talks and highlights the rational decision-making process whereby proactive leaders constantly (reassess and adjust their tactics (from unarmed to armed and vice versa as the strategic environment evolves. Horizontal and vertical communication between members is critical for enabling collective ownership of transformation processes from violent insurgency to peaceful transition and preventing internal splits and disaffection during peace negotiations. The claim that rebel organisations should be dismantled as quickly as possible during peace processes is found to be dubious, highlighting instead the importance of retaining cohesive coordination and communication structures during volatile post-war transitions.

  16. Molecular dynamics simulations of single siloxane dendrimers: Molecular structure and intramolecular mobility of terminal groups

    Science.gov (United States)

    Kurbatov, A. O.; Balabaev, N. K.; Mazo, M. A.; Kramarenko, E. Yu.

    2018-01-01

    Molecular dynamics simulations of two types of isolated siloxane dendrimers of various generations (from the 2nd to the 8th) have been performed for temperatures ranging from 150 K to 600 K. The first type of dendrimer molecules has short spacers consisting of a single oxygen atom. In the dendrimers of the second type, spacers are longer and comprised of two oxygen atoms separated by a single silicon atom. A comparative analysis of molecular macroscopic parameters such as the gyration radius and the shape factor as well as atom distributions within dendrimer interior has been performed for varying generation number, temperature, and spacer length. It has been found that the short-spacer dendrimers of the 7th and 8th generations have a stressed central part with elongated bonds and deformed valence angles. Investigation of the time evolution of radial displacements of the terminal Si atoms has shown that a fraction of the Si groups have a reduced mobility. Therefore, rather long time trajectories (of the order of tens of nanoseconds) are required to study dendrimer intramolecular dynamics.

  17. Vibrational properties of the amide group in acetanilide: A molecular-dynamics study

    Science.gov (United States)

    Campa, Alessandro; Giansanti, Andrea; Tenenbaum, Alexander

    1987-09-01

    A simplified classical model of acetanilide crystal is built in order to study the mechanisms of vibrational energy transduction in a hydrogen-bonded solid. The intermolecular hydrogen bond is modeled by an electrostatic interaction between neighboring excess charges on hydrogen and oxygen atoms. The intramolecular interaction in the peptide group is provided by a dipole-charge interaction. Forces are calculated up to second-order terms in the atomic displacements from equilibrium positions; the model is thus a chain of nonlinear coupled oscillators. Numerical molecular-dynamics experiments are performed on chain segments of five molecules. The dynamics is ordered, at all temperatures. Energy is widely exchanged between the stretching and the bending of the N-H bond, with characteristic times of the order of 0.2 ps. Energy transduction through the H bond is somewhat slower and of smaller amplitude, and is strongly reduced when the energies of the two bound molecules are very different: This could reduce the dissipation of localized energy fluctuations.

  18. Dynamic two-stage mechanism of versatile DNA damage recognition by xeroderma pigmentosum group C protein

    Energy Technology Data Exchange (ETDEWEB)

    Clement, Flurina C.; Camenisch, Ulrike; Fei, Jia; Kaczmarek, Nina; Mathieu, Nadine [Institute of Pharmacology and Toxicology, University of Zuerich-Vetsuisse, Winterthurerstrasse 260, CH-8057 Zuerich (Switzerland); Naegeli, Hanspeter, E-mail: naegelih@vetpharm.uzh.ch [Institute of Pharmacology and Toxicology, University of Zuerich-Vetsuisse, Winterthurerstrasse 260, CH-8057 Zuerich (Switzerland)

    2010-03-01

    The recognition and subsequent repair of DNA damage are essential reactions for the maintenance of genome stability. A key general sensor of DNA lesions is xeroderma pigmentosum group C (XPC) protein, which recognizes a wide variety of helix-distorting DNA adducts arising from ultraviolet (UV) radiation, genotoxic chemicals and reactive metabolic byproducts. By detecting damaged DNA sites, this unique molecular sensor initiates the global genome repair (GGR) pathway, which allows for the removal of all the aforementioned lesions by a limited repertoire of excision factors. A faulty GGR activity causes the accumulation of DNA adducts leading to mutagenesis, carcinogenesis, neurological degeneration and other traits of premature aging. Recent findings indicate that XPC protein achieves its extraordinary substrate versatility by an entirely indirect readout strategy implemented in two clearly discernible stages. First, the XPC subunit uses a dynamic sensor interface to monitor the double helix for the presence of non-hydrogen-bonded bases. This initial screening generates a transient nucleoprotein intermediate that subsequently matures into the ultimate recognition complex by trapping undamaged nucleotides in the abnormally oscillating native strand, in a way that no direct contacts are made between XPC protein and the offending lesion itself. It remains to be elucidated how accessory factors like Rad23B, centrin-2 or the UV-damaged DNA-binding complex contribute to this dynamic two-stage quality control process.

  19. Investigations of Beam Dynamics Issues at Current and Future Hadron Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Ellison, James [Univ. of New Mexico, Albuquerque, NM (United States); Lau, Stephen [Univ. of New Mexico, Albuquerque, NM (United States); Heinemann, Klaus [Univ. of New Mexico, Albuquerque, NM (United States); Bizzozero, David [Univ. of New Mexico, Albuquerque, NM (United States)

    2015-03-12

    Final Report Abstract for DE-FG02-99ER4110, May 15, 2011- October 15, 2014 There is a synergy between the fields of Beam Dynamics (BD) in modern particle accelerators and Applied Mathematics (AMa). We have formulated significant problems in BD and have developed and applied tools within the contexts of dynamical systems, topological methods, numerical analysis and scientific computing, probability and stochastic processes, and mathematical statistics. We summarize the three main areas of our AMa work since 2011. First, we continued our study of Vlasov-Maxwell systems. Previously, we developed a state of the art algorithm and code (VM3@A) to calculate coherent synchrotron radiation in single pass systems. In this cycle we carefully analyzed the major expense, namely the integral-over-history (IOH), and developed two approaches to speed up integration. The first strategy uses a representation of the Bessel function J0 in terms of exponentials. The second relies on “local sequences” developed recently for radiation boundary conditions, which are used to reduce computational domains. Although motivated by practicality, both strategies involve interesting and rather deep analysis and approximation theory. As an alternative to VM3@A, we are integrating Maxwell’s equations by a time-stepping method, bypass- ing the IOH, using a Discontinuous Galerkin (DG) method. DG is a generalization of Finite Element and Finite Volume methods. It is spectrally convergent, unlike the commonly used Finite Difference methods, and can handle complicated vacuum chamber geometries. We have applied this in several contexts and have obtained very nice results including an explanation of an experiment at the Canadian Light Source, where the geometry is quite complex. Second, we continued our study of spin dynamics in storage rings. There is much current and proposed activity where spin polarized beams are being used in testing the Standard Model and its modifications. Our work has focused

  20. Microbiota: an index of group membership, and the dynamics of social inclusion and exclusion

    Directory of Open Access Journals (Sweden)

    Augusto Jacobo Montiel Castro

    2017-12-01

    Full Text Available The possibility that microbiota mediates social behaviour and the implications of such relationship, is still a relatively recent field of research that starts to attract the interest of the scientific community. The present review compiles studies suggesting that microbiota is homogenized between different individuals through social interactions, and that, in turn, it may be differentiated as a consequence of social isolation or social exclusion. Therefore, that the study of such possibilities suggests its utility as a novel index of the dynamics of social inclusion and exclusion. One useful in evaluating whether subjects belong to specific social groups or not. We consider that these possibilities should motivate relevant empirical studies regarding the link between the homogenization of microbiota, social inclusion and exclusion, a useful effort from a diversity of research fields.

  1. Standard model group, QCD subgroup - dynamics isolating and testing the elementary QCD subprocess

    International Nuclear Information System (INIS)

    Tannenbaum, M.J.

    1982-01-01

    QCD to an experimentalist is the theory of interactions of quarks and gluons. Experimentalists like QCD because QCD is analogous to QED. Thus, following Drell and others who have for many years studied the validity of QED, one has a ready-made menu for tests of QCD. There are the static and long distance tests. These topics are covered by Peter LePage in the static properties group. In this report, dynamic and short distance tests of QCD will be discussed, primarily via reactions with large transverse momenta. This report is an introduction and overview of the subject, to serve as a framework for other reports from the subgroup. In the last two sections, the author has taken the opportunity to discuss his own ideas and opinions

  2. An algebraic approach to the inverse eigenvalue problem for a quantum system with a dynamical group

    International Nuclear Information System (INIS)

    Wang, S.J.

    1993-04-01

    An algebraic approach to the inverse eigenvalue problem for a quantum system with a dynamical group is formulated for the first time. One dimensional problem is treated explicitly in detail for both the finite dimensional and infinite dimensional Hilbert spaces. For the finite dimensional Hilbert space, the su(2) algebraic representation is used; while for the infinite dimensional Hilbert space, the Heisenberg-Weyl algebraic representation is employed. Fourier expansion technique is generalized to the generator space, which is suitable for analysis of irregular spectra. The polynormial operator basis is also used for complement, which is appropriate for analysis of some simple Hamiltonians. The proposed new approach is applied to solve the classical inverse Sturn-Liouville problem and to study the problems of quantum regular and irregular spectra. (orig.)

  3. Dynamical diffusion and renormalization group equation for the Fermi velocity in doped graphene

    International Nuclear Information System (INIS)

    Ardenghi, J.S.; Bechthold, P.; Jasen, P.; Gonzalez, E.; Juan, A.

    2014-01-01

    The aim of this work is to study the electron transport in graphene with impurities by introducing a generalization of linear response theory for linear dispersion relations and spinor wave functions. Current response and density response functions are derived and computed in the Boltzmann limit showing that in the former case a minimum conductivity appears in the no-disorder limit. In turn, from the generalization of both functions, an exact relation can be obtained that relates both. Combining this result with the relation given by the continuity equation it is possible to obtain general functional behavior of the diffusion pole. Finally, a dynamical diffusion is computed in the quasistatic limit using the definition of relaxation function. A lower cutoff must be introduced to regularize infrared divergences which allow us to obtain a full renormalization group equation for the Fermi velocity, which is solved up to order O(ℏ 2 )

  4. Dynamical R Matrices of Elliptic Quantum Groups and Connection Matrices for the q-KZ Equations

    Directory of Open Access Journals (Sweden)

    Hitoshi Konno

    2006-12-01

    Full Text Available For any affine Lie algebra ${mathfrak g}$, we show that any finite dimensional representation of the universal dynamical $R$ matrix ${cal R}(lambda$ of the elliptic quantum group ${cal B}_{q,lambda}({mathfrak g}$ coincides with a corresponding connection matrix for the solutions of the $q$-KZ equation associated with $U_q({mathfrak g}$. This provides a general connection between ${cal B}_{q,lambda}({mathfrak g}$ and the elliptic face (IRF or SOS models. In particular, we construct vector representations of ${cal R}(lambda$ for ${mathfrak g}=A_n^{(1}$, $B_n^{(1}$, $C_n^{(1}$, $D_n^{(1}$, and show that they coincide with the face weights derived by Jimbo, Miwa and Okado. We hence confirm the conjecture by Frenkel and Reshetikhin.

  5. Methyl group dynamics in paracetamol and acetanilide: probing the static properties of intermolecular hydrogen bonds formed by peptide groups

    Science.gov (United States)

    Johnson, M. R.; Prager, M.; Grimm, H.; Neumann, M. A.; Kearley, G. J.; Wilson, C. C.

    1999-06-01

    Measurements of tunnelling and librational excitations for the methyl group in paracetamol and tunnelling excitations for the methyl group in acetanilide are reported. In both cases, results are compared with molecular mechanics calculations, based on the measured low temperature crystal structures, which follow an established recipe. Agreement between calculated and measured methyl group observables is not as good as expected and this is attributed to the presence of comprehensive hydrogen bond networks formed by the peptide groups. Good agreement is obtained with a periodic quantum chemistry calculation which uses density functional methods, these calculations confirming the validity of the one-dimensional rotational model used and the crystal structures. A correction to the Coulomb contribution to the rotational potential in the established recipe using semi-emipircal quantum chemistry methods, which accommodates the modified charge distribution due to the hydrogen bonds, is investigated.

  6. Space-Time Dynamics of Soil Moisture and Temperature: Scale issues

    Science.gov (United States)

    Mohanty, Binayak P.; Miller, Douglas A.; Th.vanGenuchten, M.

    2003-01-01

    The goal of this project is to gain further understanding of soil moisture/temperature dynamics at different spatio-temporal scales and physical controls/parameters.We created a comprehensive GIS database, which has been accessed extensively by NASA Land Surface Hydrology investigators (and others), is located at the following URL: http://www.essc.psu.edu/nasalsh. For soil moisture field experiments such as SGP97, SGP99, SMEX02, and SMEX03, cartographic products were designed for multiple applications, both pre- and post-mission. Premission applications included flight line planning and field operations logistics, as well as general insight into the extent and distribution of soil, vegetation, and topographic properties for the study areas. The cartographic products were created from original spatial information resources that were imported into Adobe Illustrator, where the maps were created and PDF versions were made for distribution and download.

  7. Modelling voltage sag mitigation using dynamic voltage restorer and analyzing power quality issue

    Science.gov (United States)

    Ismail, Nor Laili; Hidzir, Hizrin Dayana Mohd; Thanakodi, Suresh; Nazar, Nazatul Shiema Moh; Ibrahim, Pungut; Ali, Che Ku Muhammad Sabri Che Ku

    2018-02-01

    Power quality problem which are arise due to a fault or a pulsed load can have caused an interruption of critical load. The modern power systems are becoming more sensitive to the quality of the power supplied by the utility company. Voltage sags and swells, flicker, interruptions, harmonic distortion and other distortion to the sinusoidal waveform are the examples of the power quality problems. The most affected due to these problems is industrial customers who use a lot of sensitive equipment. There has suffered a huge loss to these problems. Resulting of broken or damage equipment if voltage sag exceeds the sensitive threshold of the equipment. Thus, device such as Static Synchronous Compensator (STATCOM) and Dynamic Voltage Restorer (DVR) has been created to solve this problem among users. DVR is a custom power device that most effective and efficient. This paper intended to report the DVR operations during voltage sag compensation.

  8. Research, development and demonstration. Issue paper - working group 3; Denmark. Smart Grid Network; Forskning, udvikling og demonstration. Issue paper, arbejdsgruppe 3

    Energy Technology Data Exchange (ETDEWEB)

    Balasiu, A [Siemens A/S, Ballerup (Denmark); Troi, A [Danmarks Tekniske Univ. Risoe Nationallaboratoriet for Baeredygtig Energi, Roskilde (Denmark); Andersen, Casper [DI Energibranchen, Copenhagen (Denmark); and others

    2011-07-01

    The Smart Grid Network was established in 2010 by the Danish climate and energy minister tasked with developing recommendations for future actions and initiatives that make it possible to handle up to 50% electricity from wind energy in the power system in 2020. The task of working group 3 was defined as: - An overview of the Danish research and development of smart grids and related areas; - Conducting an analysis of the research and development needs required for the introduction of a smart grid in Denmark. Based on this analysis, provide suggestions for new large research and development projects; - Provide recommendations on how the activities are best carried out taking into account innovation, economic growth and jobs. In the analysis it is explained that Denmark so far has a strong position in several elements of RD and D activities. This position will soon be threatened as several European countries have launched ambitious initiatives to strengthen the national position. The working group recommends that Denmark gives priority to Smart Grids as a national action in order to solve the challenge of technically and economically efficient integration of renewable energy. Smart Grid is a catalyst that strengthens a new green growth industry (cleantech) in Denmark. Research and development has an important role to play in this development. A common vision and roadmap must be established for research institutions, energy companies and industries related to research, development and demonstration of Smart Grid, which can maintain and expand Denmark's global leadership position. As part of this, there is a need to strengthen and market research infrastructures, which can turn Denmark into a global hub for smart grid development. There is a current need to strengthen the advanced technical and scientific research in the complexities of the power system, research on market design, user behavior and smart grid interoperability. (LN)

  9. Research, development and demonstration. Issue paper - working group 3; Denmark. Smart Grid Network; Forskning, udvikling og demonstration. Issue paper, arbejdsgruppe 3

    Energy Technology Data Exchange (ETDEWEB)

    Balasiu, A. (Siemens A/S, Ballerup (Denmark)); Troi, A. (Danmarks Tekniske Univ.. Risoe Nationallaboratoriet for Baeredygtig Energi, Roskilde (Denmark)); Andersen, Casper (DI Energibranchen, Copenhagen (Denmark)) (and others)

    2011-07-01

    The Smart Grid Network was established in 2010 by the Danish climate and energy minister tasked with developing recommendations for future actions and initiatives that make it possible to handle up to 50% electricity from wind energy in the power system in 2020. The task of working group 3 was defined as: - An overview of the Danish research and development of smart grids and related areas; - Conducting an analysis of the research and development needs required for the introduction of a smart grid in Denmark. Based on this analysis, provide suggestions for new large research and development projects; - Provide recommendations on how the activities are best carried out taking into account innovation, economic growth and jobs. In the analysis it is explained that Denmark so far has a strong position in several elements of RD and D activities. This position will soon be threatened as several European countries have launched ambitious initiatives to strengthen the national position. The working group recommends that Denmark gives priority to Smart Grids as a national action in order to solve the challenge of technically and economically efficient integration of renewable energy. Smart Grid is a catalyst that strengthens a new green growth industry (cleantech) in Denmark. Research and development has an important role to play in this development. A common vision and roadmap must be established for research institutions, energy companies and industries related to research, development and demonstration of Smart Grid, which can maintain and expand Denmark's global leadership position. As part of this, there is a need to strengthen and market research infrastructures, which can turn Denmark into a global hub for smart grid development. There is a current need to strengthen the advanced technical and scientific research in the complexities of the power system, research on market design, user behavior and smart grid interoperability. (LN)

  10. Dynamic triggering of volcano drumbeat-like seismicity at the Tatun volcano group in Taiwan

    Science.gov (United States)

    Lin, Cheng-Horng

    2017-07-01

    Periodical seismicity during eruptions has been observed at several volcanoes, such as Mount St. Helens and Soufrière Hills. Movement of magma is often considered one of the most important factors in its generation. Without any magma movement, drumbeat-like (or heartbeat-like) periodical seismicity was detected twice beneath one of the strongest fumarole sites (Dayoukeng) among the Tatun volcano group in northern Taiwan in 2015. Both incidences of drumbeat-like seismicity were respectively started after felt earthquakes in Taiwan, and then persisted for 1-2 d afterward with repetition intervals of ∼18 min between any two adjacent events. The phenomena suggest both drumbeat-like (heartbeat-like) seismicity sequences were likely triggered by dynamic waves generated by the two felt earthquakes. Thus, rather than any involvement of magma, a simplified pumping system within a degassing conduit is proposed to explain the generation of drumbeat-like seismicity. The collapsed rocks within the conduit act as a piston, which was repeatedly lifted up by ascending gas from a deeper reservoir and dropped down when the ascending gas was escaping later. These phenomena show that the degassing process is still very strong in the Tatun volcano group in Taiwan, even though it has been dormant for about several thousand years.

  11. Group Dynamics as a Critical Component of Successful Space Exploration: Conceptual Theory and Insights from the Biosphere 2 Closure Experiment

    Science.gov (United States)

    Nelson, Mark; Allen, John P.

    As space exploration and eventually habitation achieves longer durations, successfully managing group dynamics of small, physically isolated groups will become vital. The paper summarizes important underlying research and conceptual theory and how these manifested in a well-documented example: the closure experiments of Biosphere 2. Key research breakthroughs in discerning the operation of small human groups comes from the pioneering work of W.R. Bion. He discovered two competing modalities of behavior. The first is the “task-oriented” or work group governed by shared acceptance of goals, reality-thinking in relation to time, resources and rational, and intelligent management of challenges presented. The opposing, usually unconscious, modality is what Bion called the “basic-assumption” group and alternates between three “group animal” groups: dependency/kill the leader; fight/flight and pairing. If not dealt with, these dynamics work to undermine and defeat the conscious task group’s goal achievement. The paper discusses crew training and selection, various approaches to structuring the work and hierarchy of the group, the importance of contact with a larger population through electronic communication and dealing with the “us-them” syndrome frequently observed between crew and Mission Control. The experience of the first two year closure of Biosphere 2 is drawn on in new ways to illustrate vicissitudes and management of group dynamics especially as both the inside team of biospherians and key members of Mission Control had training in working with group dynamics. Insights from that experience may help mission planning so that future groups in space cope successfully with inherent group dynamics challenges that arise.

  12. 41 CFR 301-71.102 - May we issue a single authorization for a group of employees?

    Science.gov (United States)

    2010-07-01

    ... Federal Travel Regulation System TEMPORARY DUTY (TDY) TRAVEL ALLOWANCES AGENCY RESPONSIBILITIES 71-AGENCY TRAVEL ACCOUNTABILITY REQUIREMENTS Travel Authorization § 301-71.102 May we issue a single authorization... are traveling together on a single trip. However, you must attach a list of all travelers to the...

  13. Ethical issues regarding the donation and source of cells for tissue engineering: a European focus group study

    NARCIS (Netherlands)

    Oerlemans, A.J.M.; Berg, P.P. van den; Leeuwen, E. van; Dekkers, W.J.M.

    2011-01-01

    This article is part of the EuroSTEC project, which aims at developing tissue engineering-based treatments for structural disorders present at birth. EuroSTEC is positioned at the intersection of three areas with their own ethical issues: (1) regenerative medicine, (2) research with pregnant women

  14. Minority Language Issues in Chinese Higher Education: Policy Reforms and Practice among the Korean and Mongol Ethnic Groups

    Science.gov (United States)

    Xiong, Weiyan; Jacob, W. James; Ye, Huiyuan

    2016-01-01

    The purpose of this study is to compare Korean and Mongol minorities in the People's Republic of China in terms of their native language preservation and educational experiences at the higher education level, and to investigate differences and similarities between Korean and Mongol minorities' language issues. Content area experts on Chinese…

  15. Ethical issues regarding the donation and source of cells for tissue engineering : a European focus group study

    NARCIS (Netherlands)

    van den Berg, P.P.; van Leeuwen, E.; Dekkers, W.J.M.; Oerlemans, A.J.

    This article is part of the EuroSTEC project, which aims at developing tissue engineering-based treatments for structural disorders present at birth. EuroSTEC is positioned at the intersection of three areas with their own ethical issues: (1) regenerative medicine, (2) research with pregnant women

  16. Are the Deaf a Disabled Group, or a Linguistic Minority? Issues for Librarians in Victoria's Public Libraries

    Science.gov (United States)

    McQuigg, Karen

    2003-01-01

    Presents a brief overview of the sociological forces shaping the discourse of disability; examines the part that public libraries have played, or failed to play, in addressing issues of exclusion as they relate to people with disabilities. Focuses on Australia's deaf community and its particular informational needs. The low impact of the…

  17. Consciousness viewed in the framework of brain phase space dynamics, criticality, and the Renormalization Group

    International Nuclear Information System (INIS)

    Werner, Gerhard

    2013-01-01

    The topic of this paper will be addressed in three stages: I will first review currently prominent theoretical conceptualizations of the neurobiology of consciousness and, where appropriate, identify ill-advised and flawed notions in theoretical neuroscience that may impede viewing consciousness as a phenomenon in the physics of brain. In this context, I will also introduce relevant facts that tend not to receive adequate attention in much of the current consciousness discourse. Next, I will review the evidence that accrued in the last decade that identifies the resting brain as being in a state of criticality. In the framework of state phase dynamics of statistical physics, this observational evidence also entails that the resting brain is poised at the brink of a second order phase transition. On this basis, I will in the third stage propose applying the framework of the Renormalization Group to viewing consciousness as a phenomenon in statistical physics. In physics, concepts of phase space transitions and the Renormalization Group are powerful tools for interpreting phenomena involving many scales of length and time in complex systems. The significance of these concepts lies in their accounting for the emergence of different levels of new collective behaviors in complex systems, each level with its distinct macroscopic physics, organization, and laws, as a new pattern of reality. In this framework, I propose to view subjectivity as the symbolic description of the physical brain state of consciousness that emerges as one of the levels of phase transitions of the brain-body-environment system, along the trajectory of Renormalization Group Transformations

  18. Strong-coupling Bose polarons out of equilibrium: Dynamical renormalization-group approach

    Science.gov (United States)

    Grusdt, Fabian; Seetharam, Kushal; Shchadilova, Yulia; Demler, Eugene

    2018-03-01

    When a mobile impurity interacts with a surrounding bath of bosons, it forms a polaron. Numerous methods have been developed to calculate how the energy and the effective mass of the polaron are renormalized by the medium for equilibrium situations. Here, we address the much less studied nonequilibrium regime and investigate how polarons form dynamically in time. To this end, we develop a time-dependent renormalization-group approach which allows calculations of all dynamical properties of the system and takes into account the effects of quantum fluctuations in the polaron cloud. We apply this method to calculate trajectories of polarons following a sudden quench of the impurity-boson interaction strength, revealing how the polaronic cloud around the impurity forms in time. Such trajectories provide additional information about the polaron's properties which are challenging to extract directly from the spectral function measured experimentally using ultracold atoms. At strong couplings, our calculations predict the appearance of trajectories where the impurity wavers back at intermediate times as a result of quantum fluctuations. Our method is applicable to a broader class of nonequilibrium problems. As a check, we also apply it to calculate the spectral function and find good agreement with experimental results. At very strong couplings, we predict that quantum fluctuations lead to the appearance of a dark continuum with strongly suppressed spectral weight at low energies. While our calculations start from an effective Fröhlich Hamiltonian describing impurities in a three-dimensional Bose-Einstein condensate, we also calculate the effects of additional terms in the Hamiltonian beyond the Fröhlich paradigm. We demonstrate that the main effect of these additional terms on the attractive side of a Feshbach resonance is to renormalize the coupling strength of the effective Fröhlich model.

  19. Dynamic virtual fixture on the Euclidean group for admittance-type manipulator in deforming environments.

    Science.gov (United States)

    Zhang, Dongwen; Zhu, Qingsong; Xiong, Jing; Wang, Lei

    2014-04-27

    In a deforming anatomic environment, the motion of an instrument suffers from complex geometrical and dynamic constraints, robot assisted minimally invasive surgery therefore requires more sophisticated skills for surgeons. This paper proposes a novel dynamic virtual fixture (DVF) to enhance the surgical operation accuracy of admittance-type medical robotics in the deforming environment. A framework for DVF on the Euclidean Group SE(3) is presented, which unites rotation and translation in a compact form. First, we constructed the holonomic/non-holonomic constraints, and then searched for the corresponded reference to make a distinction between preferred and non-preferred directions. Second, different control strategies are employed to deal with the tasks along the distinguished directions. The desired spatial compliance matrix is synthesized from an allowable motion screw set to filter out the task unrelated components from manual input, the operator has complete control over the preferred directions; while the relative motion between the surgical instrument and the anatomy structures is actively tracked and cancelled, the deviation relative to the reference is compensated jointly by the operator and DVF controllers. The operator, haptic device, admittance-type proxy and virtual deforming environment are involved in a hardware-in-the-loop experiment, human-robot cooperation with the assistance of DVF controller is carried out on a deforming sphere to simulate beating heart surgery, performance of the proposed DVF on admittance-type proxy is evaluated, and both human factors and control parameters are analyzed. The DVF can improve the dynamic properties of human-robot cooperation in a low-frequency (0 ~ 40 rad/sec) deforming environment, and maintain synergy of orientation and translation during the operation. Statistical analysis reveals that the operator has intuitive control over the preferred directions, human and the DVF controller jointly control the

  20. Fort Collins Science Center Ecosystem Dynamics branch--interdisciplinary research for addressing complex natural resource issues across landscapes and time

    Science.gov (United States)

    Bowen, Zachary H.; Melcher, Cynthia P.; Wilson, Juliette T.

    2013-01-01

    The Ecosystem Dynamics Branch of the Fort Collins Science Center offers an interdisciplinary team of talented and creative scientists with expertise in biology, botany, ecology, geology, biogeochemistry, physical sciences, geographic information systems, and remote-sensing, for tackling complex questions about natural resources. As demand for natural resources increases, the issues facing natural resource managers, planners, policy makers, industry, and private landowners are increasing in spatial and temporal scope, often involving entire regions, multiple jurisdictions, and long timeframes. Needs for addressing these issues include (1) a better understanding of biotic and abiotic ecosystem components and their complex interactions; (2) the ability to easily monitor, assess, and visualize the spatially complex movements of animals, plants, water, and elements across highly variable landscapes; and (3) the techniques for accurately predicting both immediate and long-term responses of system components to natural and human-caused change. The overall objectives of our research are to provide the knowledge, tools, and techniques needed by the U.S. Department of the Interior, state agencies, and other stakeholders in their endeavors to meet the demand for natural resources while conserving biodiversity and ecosystem services. Ecosystem Dynamics scientists use field and laboratory research, data assimilation, and ecological modeling to understand ecosystem patterns, trends, and mechanistic processes. This information is used to predict the outcomes of changes imposed on species, habitats, landscapes, and climate across spatiotemporal scales. The products we develop include conceptual models to illustrate system structure and processes; regional baseline and integrated assessments; predictive spatial and mathematical models; literature syntheses; and frameworks or protocols for improved ecosystem monitoring, adaptive management, and program evaluation. The descriptions

  1. Summary report of the group on single-particle nonlinear dynamics

    International Nuclear Information System (INIS)

    Axinescu, S.; Bartolini, R.; Bazzani, A.

    1996-10-01

    This report summarizes the research on single-particle nonlinear beam dynamics. It discusses the following topics: analytical and semi-analytical tools; early prediction of the dynamic aperture; how the results are commonly presented; Is the mechanism of the dynamic aperture understand; ripple effects; and beam-beam effects

  2. Minority Language Issues in Chinese Higher Education: Policy Reforms and Practice among the Korean and Mongol Ethnic Groups

    Institute of Scientific and Technical Information of China (English)

    Weiyan XIONG; W.James JACOB; Huiyuan YE

    2016-01-01

    The purpose of this study is to compare Korean and Mongol minorities in the People's Republic of China in terms of their native language preservation and educational experiences at the higher education level,and to investigate differences and similarities between Korean and Mongol minorities' language issues.Content area experts on Chinese minority education from China,South Korea,and the United States were interviewed for this study.Findings include suggestions for helping to formulate government educational policies regarding issues related to language in Chinese minority education at the higher education level.This information is helpful to better understand and educate others in school and home settings where Chinese ethnic minority students reside.The advancement of Chinese minority education knowledge related to higher education will significantly strengthen and empower individuals,families,and communities throughout the People's Republic of China.

  3. Real-Time Station Grouping under Dynamic Traffic for IEEE 802.11ah.

    Science.gov (United States)

    Tian, Le; Khorov, Evgeny; Latré, Steven; Famaey, Jeroen

    2017-07-04

    RAW grouping under dynamic traffic in real time, which is a major leap towards applying RAW mechanism in real-life IoT networks.

  4. Effects of group dynamics and diet on the ranging patterns of a western gorilla group (Gorilla gorilla gorilla) at Bai Hokou, Central African Republic.

    Science.gov (United States)

    Cipolletta, Chloé

    2004-10-01

    This study describes how group dynamics and diet have influenced the ranging patterns of a western gorilla group at Bai Hokou, Central African Republic. The results are compared with those from an earlier study [Cipolletta, International Journal of Primatology, 2003], when the same group was larger and undergoing the process of habituation to humans. Data were obtained from maps of the gorillas' travel routes, direct observations, and analysis of fecal samples. Through the years, the group has experienced a decrease in size, from eight to three individuals, with periods of membership fluctuation. The male's search for new mates resulted in a larger home range than was recorded when the group consisted of more individuals. Moreover, despite an average group size of three throughout this study, the monthly range and mean daily path length (DPL) were also larger when the group was acquiring/losing members in new areas, than when no new members joined or left the group. Fruit was consumed year-round, although more heavily so during wet months. The influence of fruit consumption on the ranging patterns was concealed initially by the effect of habituation [Cipolletta, International Journal of Primatology, 2003], and later (at least partially) by the male's search for new mates. In the last 14 months of the study, when the group numbered only three individuals and was ranging in a restricted area, the average DPL, but not the monthly range, increased when the gorillas were consuming more fruit.

  5. A Mathematical Framework for the Complex System Approach to Group Dynamics: The Case of Recovery House Social Integration.

    Science.gov (United States)

    Light, John M; Jason, Leonard A; Stevens, Edward B; Callahan, Sarah; Stone, Ariel

    2016-03-01

    The complex system conception of group social dynamics often involves not only changing individual characteristics, but also changing within-group relationships. Recent advances in stochastic dynamic network modeling allow these interdependencies to be modeled from data. This methodology is discussed within a context of other mathematical and statistical approaches that have been or could be applied to study the temporal evolution of relationships and behaviors within small- to medium-sized groups. An example model is presented, based on a pilot study of five Oxford House recovery homes, sober living environments for individuals following release from acute substance abuse treatment. This model demonstrates how dynamic network modeling can be applied to such systems, examines and discusses several options for pooling, and shows how results are interpreted in line with complex system concepts. Results suggest that this approach (a) is a credible modeling framework for studying group dynamics even with limited data, (b) improves upon the most common alternatives, and (c) is especially well-suited to complex system conceptions. Continuing improvements in stochastic models and associated software may finally lead to mainstream use of these techniques for the study of group dynamics, a shift already occurring in related fields of behavioral science.

  6. Efficient traffic grooming with dynamic ONU grouping for multiple-OLT-based access network

    Science.gov (United States)

    Zhang, Shizong; Gu, Rentao; Ji, Yuefeng; Wang, Hongxiang

    2015-12-01

    Fast bandwidth growth urges large-scale high-density access scenarios, where the multiple Passive Optical Networking (PON) system clustered deployment can be adopted as an appropriate solution to fulfill the huge bandwidth demands, especially for a future 5G mobile network. However, the lack of interaction between different optical line terminals (OLTs) results in part of the bandwidth resources waste. To increase the bandwidth efficiency, as well as reduce bandwidth pressure at the edge of a network, we propose a centralized flexible PON architecture based on Time- and Wavelength-Division Multiplexing PON (TWDM PON). It can provide flexible affiliation for optical network units (ONUs) and different OLTs to support access network traffic localization. Specifically, a dynamic ONU grouping algorithm (DGA) is provided to obtain the minimal OLT outbound traffic. Simulation results show that DGA obtains an average 25.23% traffic gain increment under different OLT numbers within a small ONU number situation, and the traffic gain will increase dramatically with the increment of the ONU number. As the DGA can be deployed easily as an application running above the centralized control plane, the proposed architecture can be helpful to improve the network efficiency for future traffic-intensive access scenarios.

  7. Dynamical mean-field theory and path integral renormalisation group calculations of strongly correlated electronic states

    Energy Technology Data Exchange (ETDEWEB)

    Heilmann, D.B.

    2007-02-15

    The two-plane HUBBARD model, which is a model for some electronic properties of undoped YBCO superconductors as well as displays a MOTT metal-to-insulator transition and a metal-to-band insulator transition, is studied within Dynamical Mean-Field Theory using HIRSCH-FYE Monte Carlo. In order to find the different transitions and distinguish the types of insulator, we calculate the single-particle spectral densities, the self-energies and the optical conductivities. We conclude that there is a continuous transition from MOTT to band insulator. In the second part, ground state properties of a diagonally disordered HUBBARD model is studied using a generalisation of Path Integral Renormalisation Group, a variational method which can also determine low-lying excitations. In particular, the distribution of antiferromagnetic properties is investigated. We conclude that antiferromagnetism breaks down in a percolation-type transition at a critical disorder, which is not changed appreciably by the inclusion of correlation effects, when compared to earlier studies. Electronic and excitation properties at the system sizes considered turn out to primarily depend on the geometry. (orig.)

  8. Dynamical mean-field theory and path integral renormalisation group calculations of strongly correlated electronic states

    International Nuclear Information System (INIS)

    Heilmann, D.B.

    2007-02-01

    The two-plane HUBBARD model, which is a model for some electronic properties of undoped YBCO superconductors as well as displays a MOTT metal-to-insulator transition and a metal-to-band insulator transition, is studied within Dynamical Mean-Field Theory using HIRSCH-FYE Monte Carlo. In order to find the different transitions and distinguish the types of insulator, we calculate the single-particle spectral densities, the self-energies and the optical conductivities. We conclude that there is a continuous transition from MOTT to band insulator. In the second part, ground state properties of a diagonally disordered HUBBARD model is studied using a generalisation of Path Integral Renormalisation Group, a variational method which can also determine low-lying excitations. In particular, the distribution of antiferromagnetic properties is investigated. We conclude that antiferromagnetism breaks down in a percolation-type transition at a critical disorder, which is not changed appreciably by the inclusion of correlation effects, when compared to earlier studies. Electronic and excitation properties at the system sizes considered turn out to primarily depend on the geometry. (orig.)

  9. Executive functioning in three groups of pupils in D-KEFS: Selected issues in adapting the test battery for Slovakia

    Directory of Open Access Journals (Sweden)

    Ferjenčík Ján

    2015-06-01

    Full Text Available The paper reports on the adaptation of a D-KEFS test battery for Slovakia. Drawing on concrete examples, it describes and illustrates the key issues relating to the transfer of test items from one socio-cultural environment to another. The standardisation sample of the population of Slovak pupils in the fourth year of primary school included 250 children with an average age of 9.7 years. The two comparative samples of the same age range were analysed at the same time. They included pupils from classes for gifted children (n = 55 and Roma children from socially disadvantaging environments (n = 50.

  10. Perspectives of Community Co-Researchers About Group Dynamics and Equitable Partnership Within a Community-Academic Research Team.

    Science.gov (United States)

    Vaughn, Lisa M; Jacquez, Farrah; Zhen-Duan, Jenny

    2018-04-01

    Equitable partnership processes and group dynamics, including individual, relational, and structural factors, have been identified as key ingredients to successful community-based participatory research partnerships. The purpose of this qualitative study was to investigate the key aspects of group dynamics and partnership from the perspectives of community members serving as co-researchers. Semistructured, in-depth interviews were conducted with 15 Latino immigrant co-researchers from an intervention project with Latinos Unidos por la Salud (LU-Salud), a community research team composed of Latino immigrant community members and academic investigators working in a health research partnership. A deductive framework approach guided the interview process and qualitative data analysis. The LU-Salud co-researchers described relationships, personal growth, beliefs/identity motivation (individual dynamics), coexistence (relational dynamics), diversity, and power/resource sharing (structural dynamics) as key foundational aspects of the community-academic partnership. Building on existing CBPR and team science frameworks, these findings demonstrate that group dynamics and partnership processes are fundamental drivers of individual-level motivation and meaning making, which ultimately sustain efforts of community partners to engage with the research team and also contribute to the achievement of intended research outcomes.

  11. The Himalia Satellite Group: A Case Study on the Dynamical Self-spreading of Families of Irregular Satellites and Asteroids

    Science.gov (United States)

    Li, Daohai; Christou, Apostolos A.

    2015-11-01

    Many of the outer planets' irregular satellites are grouped into families, thought to originate from collisional fragmentation (Nesvorný et al 2004, AJ). Interestingly, families associated with the largest irregulars are either more dispersed than expected (e.g. J6 Himalia; Nesvorný et al 2003, AJ), or do not exist at all (e.g. S9 Phoebe; Ćuk et al 2003, DDA meeting #34). Christou (2005, Icarus) found that gravitational scattering by Himalia of its own group could explain the large velocity dispersion found by Nesvorný et al (2003, AJ). At the same time, Christou identified a new type of dynamical mechanism that intermittently locks the node of the satellite J10 Lysithea to that of Himalia. The same mechanism, but due to Ceres, was recently found to operate within the Hoffmeister family, dispersing its members and allowing an estimate of its age (Novaković et al 2015, ApJ).Here we revisit the issue of family self-dispersion, aiming to better understand it by studying its effects on the Himalia group. For this we utilise (a) intensive test particle simulations on a larger scale than those by Christou (2005, Icarus) (b) a semi-analytical treatment of the new resonance based on the secular theory of coorbital motion by Namouni (1999, Icarus). This has allowed us to obtain firmer constraints on the rate of dispersion over time and on how the resonance affects the long-term evolution of the orbital elements. A principal result of this work is that particles near the resonance evolve differently than those away from it. During the meeting, we will present a new estimate of the family’s age as well as an analysis of the resonant structure and how it affects Himalia family members. We will also discuss the broader implications for the long-term evolution of orbital concentrations of small bodies in the solar system.Astronomical research at the Armagh Observatory is funded by the Northern Ireland Department of Culture, Arts and Leisure (DCAL).

  12. Group dynamics of zebra and wildebeest in a woodland savanna: effects of predation risk and habitat density.

    Directory of Open Access Journals (Sweden)

    Maria Thaker

    Full Text Available BACKGROUND: Group dynamics of gregarious ungulates in the grasslands of the African savanna have been well studied, but the trade-offs that affect grouping of these ungulates in woodland habitats or dense vegetation are less well understood. We examined the landscape-level distribution of groups of blue wildebeest, Connochaetes taurinus, and Burchell's zebra, Equus burchelli, in a predominantly woodland area (Karongwe Game Reserve, South Africa; KGR to test the hypothesis that group dynamics are a function of minimizing predation risk from their primary predator, lion, Panthera leo. METHODOLOGY/PRINCIPAL FINDINGS: Using generalized linear models, we examined the relative importance of habitat type (differing in vegetation density, probability of encountering lion (based on utilization distribution of all individual lions in the reserve, and season in predicting group size and composition. We found that only in open scrub habitat, group size for both ungulate species increased with the probability of encountering lion. Group composition differed between the two species and was driven by habitat selection as well as predation risk. For both species, composition of groups was, however, dominated by males in open scrub habitats, irrespective of the probability of encountering lion. CONCLUSIONS/SIGNIFICANCE: Distribution patterns of wildebeest and zebra groups at the landscape level directly support the theoretical and empirical evidence from a range of taxa predicting that grouping is favored in open habitats and when predation risk is high. Group composition reflected species-specific social, physiological and foraging constraints, as well as the importance of predation risk. Avoidance of high resource open scrub habitat by females can lead to loss of foraging opportunities, which can be particularly costly in areas such as KGR, where this resource is limited. Thus, landscape-level grouping dynamics are species specific and particular to the

  13. Group Dynamic Assessment (G-DA: The Case for the Development of Control over the Past Tense

    Directory of Open Access Journals (Sweden)

    Ehsan Mehri

    2015-09-01

    Full Text Available The introduction of dynamic assessment within sociocultural theory opened a new door toward looking at the relationship between the teaching and assessment. The dialectic relationship between the two processes provides previously unfound information regarding the assessment and the development of the learners. However, the implementation of the interactionist dynamic assessment has carried some difficulties in class in general and the groups in particular. The current study tries to address the effect of group dynamic assessment on the development of the control over the past tense; therefore, it is two-folded in the aim. Not only does it work as a practical sample of group dynamic assessment in class, but also it seeks to analyze its effect on the development of control over the past tense. To this end, three learners at the levels of elementary, low-intermediate, and intermediate general proficiency were asked to read a novel and retell the story. The dynamic intervention provided by the teacher during the story retelling was later evaluated in the transcendence tasks of writing. The Friedman test indicated that the three learners had significant development in their control over the past tense in their writing. Moreover, the qualitative analysis of the interactions suggests that the learners changed their role from the mere receivers of the teacher's mediator into the active providers of mediation to other group members. Also, they developed their understanding of the concept of the past tense through implementing it in transcendence tasks of writing.

  14. Neural dynamics of motion perception: direction fields, apertures, and resonant grouping.

    Science.gov (United States)

    Grossberg, S; Mingolla, E

    1993-03-01

    A neural network model of global motion segmentation by visual cortex is described. Called the motion boundary contour system (BCS), the model clarifies how ambiguous local movements on a complex moving shape are actively reorganized into a coherent global motion signal. Unlike many previous researchers, we analyze how a coherent motion signal is imparted to all regions of a moving figure, not only to regions at which unambiguous motion signals exist. The model hereby suggests a solution to the global aperture problem. The motion BCS describes how preprocessing of motion signals by a motion oriented contrast (MOC) filter is joined to long-range cooperative grouping mechanisms in a motion cooperative-competitive (MOCC) loop to control phenomena such as motion capture. The motion BCS is computed in parallel with the static BCS of Grossberg and Mingolla (1985a, 1985b, 1987). Homologous properties of the motion BCS and the static BCS, specialized to process motion directions and static orientations, respectively, support a unified explanation of many data about static form perception and motion form perception that have heretofore been unexplained or treated separately. Predictions about microscopic computational differences of the parallel cortical streams V1-->MT and V1-->V2-->MT are made--notably, the magnocellular thick stripe and parvocellular interstripe streams. It is shown how the motion BCS can compute motion directions that may be synthesized from multiple orientations with opposite directions of contrast. Interactions of model simple cells, complex cells, hyper-complex cells, and bipole cells are described, with special emphasis given to new functional roles in direction disambiguation for endstopping at multiple processing stages and to the dynamic interplay of spatially short-range and long-range interactions.

  15. A polarizable QM/MM approach to the molecular dynamics of amide groups solvated in water

    Energy Technology Data Exchange (ETDEWEB)

    Schwörer, Magnus; Wichmann, Christoph; Tavan, Paul, E-mail: tavan@physik.uni-muenchen.de [Lehrstuhl für BioMolekulare Optik, Ludwig-Maximilians Universität München, Oettingenstr. 67, 80538 München (Germany)

    2016-03-21

    The infrared (IR) spectra of polypeptides are dominated by the so-called amide bands. Because they originate from the strongly polar and polarizable amide groups (AGs) making up the backbone, their spectral positions sensitively depend on the local electric fields. Aiming at accurate computations of these IR spectra by molecular dynamics (MD) simulations, which derive atomic forces from a hybrid quantum and molecular mechanics (QM/MM) Hamiltonian, here we consider the effects of solvation in bulk liquid water on the amide bands of the AG model compound N-methyl-acetamide (NMA). As QM approach to NMA we choose grid-based density functional theory (DFT). For the surrounding MM water, we develop, largely based on computations, a polarizable molecular mechanics (PMM) model potential called GP6P, which features six Gaussian electrostatic sources (one induced dipole, five static partial charge distributions) and, therefore, avoids spurious distortions of the DFT electron density in hybrid DFT/PMM simulations. Bulk liquid GP6P is shown to have favorable properties at the thermodynamic conditions of the parameterization and beyond. Lennard-Jones (LJ) parameters of the DFT fragment NMA are optimized by comparing radial distribution functions in the surrounding GP6P liquid with reference data obtained from a “first-principles” DFT-MD simulation. Finally, IR spectra of NMA in GP6P water are calculated from extended DFT/PMM-MD trajectories, in which the NMA is treated by three different DFT functionals (BP, BLYP, B3LYP). Method-specific frequency scaling factors are derived from DFT-MD simulations of isolated NMA. The DFT/PMM-MD simulations with GP6P and with the optimized LJ parameters then excellently predict the effects of aqueous solvation and deuteration observed in the IR spectra of NMA. As a result, the methods required to accurately compute such spectra by DFT/PMM-MD also for larger peptides in aqueous solution are now at hand.

  16. 'Optimal conditions for group-dynamic challenges' : The results of mock-up research on group-dynamics during the January 2014 Juuka Finland ‘Ice Dome’ building by university students initiated by the Eindhoven Technical University

    NARCIS (Netherlands)

    Sanders, F.C.; Overtoom, M.E.

    2016-01-01

    Society counts a growing number of group-dynamic challenges like civilian movements, resident initia-tive, self steering teams on the work floor and innovation team challenges. The basis driving force is governments that draw back, increasing competition in business and empowerment of people.

  17. Simulating The Dynamical Evolution Of Galaxies In Group And Cluster Environments

    Science.gov (United States)

    Vijayaraghavan, Rukmani

    2015-07-01

    Galaxy clusters are harsh environments for their constituent galaxies. A variety of physical processes effective in these dense environments transform gas-rich, spiral, star-forming galaxies to elliptical or spheroidal galaxies with very little gas and therefore minimal star formation. The consequences of these processes are well understood observationally. Galaxies in progressively denser environments have systematically declining star formation rates and gas content. However, a theoretical understanding of of where, when, and how these processes act, and the interplay between the various galaxy transformation mechanisms in clusters remains elusive. In this dissertation, I use numerical simulations of cluster mergers as well as galaxies evolving in quiescent environments to develop a theoretical framework to understand some of the physics of galaxy transformation in cluster environments. Galaxies can be transformed in smaller groups before they are accreted by their eventual massive cluster environments, an effect termed `pre-processing'. Galaxy cluster mergers themselves can accelerate many galaxy transformation mechanisms, including tidal and ram pressure stripping of galaxies and galaxy-galaxy collisions and mergers that result in reassemblies of galaxies' stars and gas. Observationally, cluster mergers have distinct velocity and phase-space signatures depending on the observer's line of sight with respect to the merger direction. Using dark matter only as well as hydrodynamic simulations of cluster mergers with random ensembles of particles tagged with galaxy models, I quantify the effects of cluster mergers on galaxy evolution before, during, and after the mergers. Based on my theoretical predictions of the dynamical signatures of these mergers in combination with galaxy transformation signatures, one can observationally identify remnants of mergers and quantify the effect of the environment on galaxies in dense group and cluster environments. The presence of

  18. [Experiences of Life and Work of a Group of Epidemiologists in Training in Order to Address Mental Health Problems and Issues at Local and Departmental Level. Medellin, 2013].

    Science.gov (United States)

    Duque, María Osley Garzón; Bernal, Diana Restrepo; Cardona, Doris Alejandra Segura; Vargas, Alejandra Valencia; Salas, Ivony Agudelo; Quintero, Lina Marcela Salazar

    2014-01-01

    To examine, from the point of view of a group of epidemiologists in training, their life experiences and work related to addressing mental health problems and mental health issues. An exploratory qualitative-descriptive study was conducted using ethnographic tools, non-participant observation, note-taking, and group interviews (FG). The participants mentioned that mental health and mental health issues are managed and poorly differentiated either by them and the community in general. They also said they were not ready to handle mental problems, or have the support of services for patient care, as mental health issues have not yet been clearly dimensioned by society. Epidemiology has its limitations, it focuses on knowledge of the physical-biological aspects and the use of quantitative approach with poor integration of the qualitative approach, thus hindering the understanding of a phenomenon that exceeds the limits of a research approach. This approach to issues of health and mental illness widens the view of knowledge from only a single focus. It includes an understanding of the qualitative approach as an option to advance the knowledge and recognition of a public health problem overshadowed by stigma and apathy of society. Copyright © 2014 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

  19. Women’s Empowerment through Self-help Groups and its Impact on Health Issues: Empirical Evidence

    Directory of Open Access Journals (Sweden)

    Assist. Prof. Sudipta De

    2011-01-01

    Full Text Available Based on an empirical study in West Bengal, this paper attempts toexamine whether women’s involvement in the microcredit programmethrough SHGs makes any positive change on women’s empowerment.From the assessment of various criteria of empowerment(power,autonomy and self-reliance, entitlement, participation and awarenessand capacity-building, the study suggests that if women participatingin the microcredit programme through SHGs sustain for some longerperiod (eight years or more, such programme might contribute tohigher level of women’s empowerment than women’s empowermentunder all types of control group. This paper also finds that women’searnings from saving and credit have positive and significant effect onnutritional status of the children of women members of SHGs and onthe protein-intake for their household compared with that of amongcontrol groups.

  20. Ultrafast internal rotational dynamics of the azido group in (4S)-azidoproline: Chemical exchange 2DIR spectroscopic investigations

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyung-Koo; Park, Kwang-Hee; Joo, Cheonik; Kwon, Hyeok-Jun; Han, Hogyu [Department of Chemistry, Korea University, Seoul 136-701 (Korea, Republic of); Ha, Jeong-Hyon [Multidimensional Spectroscopy Laboratory, Korea Basic Science Institute, Seoul 136-713 (Korea, Republic of); Park, Sungnam, E-mail: spark8@korea.ac.kr [Department of Chemistry, Korea University, Seoul 136-701 (Korea, Republic of); Multidimensional Spectroscopy Laboratory, Korea Basic Science Institute, Seoul 136-713 (Korea, Republic of); Cho, Minhaeng, E-mail: mcho@korea.ac.kr [Department of Chemistry, Korea University, Seoul 136-701 (Korea, Republic of); Multidimensional Spectroscopy Laboratory, Korea Basic Science Institute, Seoul 136-713 (Korea, Republic of); Research Institute for Natural Sciences, Korea University, Seoul 136-713 (Korea, Republic of)

    2012-03-02

    Graphical abstract: Internal rotational dynamics of the azido group in SA (Ac-(4S)-Azp-NHMe) was studied in real time by using ultrafast 2DIR spectroscopic method. The time constant of the internal rotation around the C{sup {gamma}}-N{sup {delta}} bond in SA was determined to be {tau}{sub ir} = 5.1 ps, which is found to be much faster than that around the C-C bond in ethane. Highlights: Black-Right-Pointing-Pointer Femtosecond two-dimensional IR spectroscopy of internal rotational dynamics. Black-Right-Pointing-Pointer Stereo-electronic effects of azido group in azido-derivatized proline peptide. Black-Right-Pointing-Pointer The timescale of the azido group internal rotation is about 5.1 ps. - Abstract: The azido group in 4-azidoproline (Azp) derivative, SA (Ac-(4S)-Azp-NHMe), can form an intramolecular electrostatic interaction with the backbone peptide in the s-trans and C{sup {gamma}}-endo conformations of SA. As a result, the azido group exists as two forms, bound and free, which are defined by the presence and absence of such interaction, respectively. The bound and free azido forms are spectrally resolved in the azido IR spectrum of SA in CHCl{sub 3}. Using the two-dimensional infrared (2DIR) and polarization-controlled IR pump-probe methods, we investigated the internal rotational and orientational relaxation dynamics of the azido group and determined the internal rotational time constant of the azido group to be 5.1 ps. The internal rotational motion is found to be responsible for the early part of the orientational relaxation of the azido group in SA. Thus, the femtosecond 2DIR spectroscopy is shown to be an ideal tool for studying ultrafast conformational dynamics of SA.

  1. Renormalization group and instantons in stochastic nonlinear dynamics, from self-organized criticality to thermonuclear reactors

    International Nuclear Information System (INIS)

    Volchenkov, D.

    2009-01-01

    Stochastic counterparts of nonlinear dynamics are studied by means of nonperturbative functional methods developed in the framework of quantum field theory (QFT). In particular, we discuss fully developed turbulence, including leading corrections on possible compressibility of fluids, transport through porous media, theory of waterspouts and tsunami waves, stochastic magnetohydrodynamics, turbulent transport in crossed fields, self-organized criticality, and dynamics of accelerated wrinkled flame fronts advancing in a wide canal. This report would be of interest to the broad auditorium of physicists and applied mathematicians, with a background in nonperturbative QFT methods or nonlinear dynamical systems, having an interest in both methodological developments and interdisciplinary applications. (author)

  2. Renormalization group and instantons in stochastic nonlinear dynamics, from self-organized criticality to thermonuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Volchenkov, D. [Bielefeld Univ., Center of Excellence Cognitive Interaction Technology (CITEC) (Germany)

    2009-03-15

    Stochastic counterparts of nonlinear dynamics are studied by means of nonperturbative functional methods developed in the framework of quantum field theory (QFT). In particular, we discuss fully developed turbulence, including leading corrections on possible compressibility of fluids, transport through porous media, theory of waterspouts and tsunami waves, stochastic magnetohydrodynamics, turbulent transport in crossed fields, self-organized criticality, and dynamics of accelerated wrinkled flame fronts advancing in a wide canal. This report would be of interest to the broad auditorium of physicists and applied mathematicians, with a background in nonperturbative QFT methods or nonlinear dynamical systems, having an interest in both methodological developments and interdisciplinary applications. (author)

  3. Making instruction and assessment responsive to diverse students' progress: group-administered dynamic assessment in teaching mathematics.

    Science.gov (United States)

    Jeltova, Ida; Birney, Damian; Fredine, Nancy; Jarvin, Linda; Sternberg, Robert J; Grigorenko, Elena L

    2011-01-01

    This study entailed a 3 (instructional intervention) × 2 (assessment-type) between-subjects experimental design employing a pretest-intervention-posttest methodology. The instructional interventions were administered between subjects in three conditions: (a) dynamic instruction, (b) triarchic or theory of successful intelligence-control instruction, and (c) standard-control instruction. The assessment-type consisted between subjects of either (a) a group-administered dynamic posttest or (b) the same group-administered posttest interspersed with a control filler activity. Performance in different mathematics content areas taught in fourth grade was investigated. In total, 1,332 students and 63 classroom teachers in 24 schools across six school districts participated in the study. The results indicate the advantages of using dynamic instruction and assessment in regular classrooms while teaching mathematics, especially when the student body is highly ethnically diverse.

  4. Neutron to proton mass difference, parton distribution functions and baryon resonances from dynamics on the Lie group u(3)

    DEFF Research Database (Denmark)

    Trinhammer, Ole

    PiMinus invariant mass in B decays. We give a controversial prediction of the relative neutron to proton mass difference 0.138 % as originating in period doublings of certain parametric states. The group space dynamics communicates with real space via the exterior derivative which projects out quark and gluon...

  5. Barriers to Eating Traditional Foods Vary by Age Group in Ecuador With Biodiversity Loss as a Key Issue.

    Science.gov (United States)

    Penafiel, Daniela; Termote, Celine; Lachat, Carl; Espinel, Ramon; Kolsteren, Patrick; Van Damme, Patrick

    2016-04-01

    To document the perceptions of indigenous peoples for the sustainable management of natural resources against malnutrition. Initially 4 and then 12 interviews were conducted with 4 different age groups. Eight rural villages in Guasaganda, central Ecuador, were studied in 2011-2012. A total of 75 people (22 children, 18 adolescents, 20 adults, and 15 elders). Benefits, severity, susceptibility, barriers, cues to action, and self-efficacy of eating traditional foods. Qualitative content analysis was completed using NVivo software. Initial analysis was inductive, followed by a content analysis directed by the Health Belief Model. Coding was completed independently by 2 researchers and kappa statistics (κ ≥ 0.65) were used to evaluate agreement. Healthy perceptions toward traditional foods existed and differed by age. Local young people ate traditional foods for their health benefits and good taste; adults cultivated traditional foods that had an economic benefit. Traditional knowledge used for consumption and cultivation of traditional foods was present but needs to be disseminated. Nutrition education in schools is needed that supports traditional knowledge in younger groups and prevents dietary changes toward unhealthy eating. Increased production of traditional food is needed to address current economic realities. Copyright © 2016 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.

  6. Dynamic Difficulty Adaptation for Heterogeneously Skilled Player Groups in Multiplayer Collaborative Games

    OpenAIRE

    Greciano, Miguel Cristian

    2016-01-01

    This work focuses on the combination of two key concepts: Dynamic Difficulty Adjustment/Adaptation (video games adapting their difficulty according to the in-game performance of players, making themselves easier if the player performs poorly or more difficult if the player performs well) and Collaborative Multiplayer Games (video games where two or more human players work together to achieve a common goal). It considers and analyzes the challenges, potential and possibilities of Dynamic Diffi...

  7. Group 2 Innate Lymphoid Cells Exhibit a Dynamic Phenotype in Allergic Airway Inflammation

    Science.gov (United States)

    Li, Bobby W. S.; Stadhouders, Ralph; de Bruijn, Marjolein J. W.; Lukkes, Melanie; Beerens, Dior M. J. M.; Brem, Maarten D.; KleinJan, Alex; Bergen, Ingrid; Vroman, Heleen; Kool, Mirjam; van IJcken, Wilfred F. J.; Rao, Tata Nageswara; Fehling, Hans Jörg; Hendriks, Rudi W.

    2017-01-01

    Group 2 innate lymphoid cells (ILC2) are implicated in allergic asthma as an early innate source of the type 2 cytokines IL-5 and IL-13. However, their induction in house dust mite (HDM)-mediated airway inflammation additionally requires T cell activation. It is currently unknown whether phenotypic differences exist between ILC2s that are activated in a T cell-dependent or T cell-independent fashion. Here, we compared ILC2s in IL-33- and HDM-driven airway inflammation. Using flow cytometry, we found that surface expression levels of various markers frequently used to identify ILC2s were dependent on their mode of activation, highly variable over time, and differed between tissue compartments, including bronchoalveolar lavage (BAL) fluid, lung, draining lymph nodes, and spleen. Whereas in vivo IL-33-activated BAL fluid ILC2s exhibited an almost uniform CD25+CD127+T1/ST2+ICOS+KLRG1+ phenotype, at a comparable time point after HDM exposure BAL fluid ILC2s had a very heterogeneous surface marker phenotype. A major fraction of HDM-activated ILC2s were CD25lowCD127+T1/ST2low ICOSlowKLRG1low, but nevertheless had the capacity to produce large amounts of type 2 cytokines. HDM-activated CD25low ILC2s in BAL fluid and lung rapidly reverted to CD25high ILC2s upon in vivo stimulation with IL-33. Genome-wide transcriptional profiling of BAL ILC2s revealed ~1,600 differentially expressed genes: HDM-stimulated ILC2s specifically expressed genes involved in the regulation of adaptive immunity through B and T cell interactions, whereas IL-33-stimulated ILC2s expressed high levels of proliferation-related and cytokine genes. In both airway inflammation models ILC2s were present in the lung submucosa close to epithelial cells, as identified by confocal microscopy. In chronic HDM-driven airway inflammation ILC2s were also found inside organized cellular infiltrates near T cells. Collectively, our findings show that ILC2s are phenotypically more heterogeneous than previously thought

  8. Group 2 Innate Lymphoid Cells Exhibit a Dynamic Phenotype in Allergic Airway Inflammation

    Directory of Open Access Journals (Sweden)

    Bobby W. S. Li

    2017-12-01

    Full Text Available Group 2 innate lymphoid cells (ILC2 are implicated in allergic asthma as an early innate source of the type 2 cytokines IL-5 and IL-13. However, their induction in house dust mite (HDM-mediated airway inflammation additionally requires T cell activation. It is currently unknown whether phenotypic differences exist between ILC2s that are activated in a T cell-dependent or T cell-independent fashion. Here, we compared ILC2s in IL-33- and HDM-driven airway inflammation. Using flow cytometry, we found that surface expression levels of various markers frequently used to identify ILC2s were dependent on their mode of activation, highly variable over time, and differed between tissue compartments, including bronchoalveolar lavage (BAL fluid, lung, draining lymph nodes, and spleen. Whereas in vivo IL-33-activated BAL fluid ILC2s exhibited an almost uniform CD25+CD127+T1/ST2+ICOS+KLRG1+ phenotype, at a comparable time point after HDM exposure BAL fluid ILC2s had a very heterogeneous surface marker phenotype. A major fraction of HDM-activated ILC2s were CD25lowCD127+T1/ST2low ICOSlowKLRG1low, but nevertheless had the capacity to produce large amounts of type 2 cytokines. HDM-activated CD25low ILC2s in BAL fluid and lung rapidly reverted to CD25high ILC2s upon in vivo stimulation with IL-33. Genome-wide transcriptional profiling of BAL ILC2s revealed ~1,600 differentially expressed genes: HDM-stimulated ILC2s specifically expressed genes involved in the regulation of adaptive immunity through B and T cell interactions, whereas IL-33-stimulated ILC2s expressed high levels of proliferation-related and cytokine genes. In both airway inflammation models ILC2s were present in the lung submucosa close to epithelial cells, as identified by confocal microscopy. In chronic HDM-driven airway inflammation ILC2s were also found inside organized cellular infiltrates near T cells. Collectively, our findings show that ILC2s are phenotypically more heterogeneous than

  9. The primary case is not enough: Variation among individuals, groups and social networks modify bacterial transmission dynamics.

    Science.gov (United States)

    Keiser, Carl N; Pinter-Wollman, Noa; Ziemba, Michael J; Kothamasu, Krishna S; Pruitt, Jonathan N

    2018-03-01

    The traits of the primary case of an infectious disease outbreak, and the circumstances for their aetiology, potentially influence the trajectory of transmission dynamics. However, these dynamics likely also depend on the traits of the individuals with whom the primary case interacts. We used the social spider Stegodyphus dumicola to test how the traits of the primary case, group phenotypic composition and group size interact to facilitate the transmission of a GFP-labelled cuticular bacterium. We also compared bacterial transmission across experimentally generated "daisy-chain" vs. "star" networks of social interactions. Finally, we compared social network structure across groups of different sizes. Groups of 10 spiders experienced more bacterial transmission events compared to groups of 30 spiders, regardless of groups' behavioural composition. Groups containing only one bold spider experienced the lowest levels of bacterial transmission regardless of group size. We found no evidence for the traits of the primary case influencing any transmission dynamics. In a second experiment, bacteria were transmitted to more individuals in experimentally induced star networks than in daisy-chains, on which transmission never exceeded three steps. In both experimental network types, transmission success depended jointly on the behavioural traits of the interacting individuals; however, the behavioural traits of the primary case were only important for transmission on star networks. Larger social groups exhibited lower interaction density (i.e. had a low ratio of observed to possible connections) and were more modular, i.e. they had more connections between nodes within a subgroup and fewer connections across subgroups. Thus, larger groups may restrict transmission by forming fewer interactions and by isolating subgroups that interacted with the primary case. These findings suggest that accounting for the traits of single exposed hosts has less power in predicting transmission

  10. Framing Negotiation: Dynamics of Epistemological and Positional Framing in Small Groups during Scientific Modeling

    Science.gov (United States)

    Shim, Soo-Yean; Kim, Heui-Baik

    2018-01-01

    In this study, we examined students' epistemological and positional framing during small group scientific modeling to explore their context-dependent perceptions about knowledge, themselves, and others. We focused on two small groups of Korean eighth-grade students who participated in six modeling activities about excretion. The two groups were…

  11. Renormalization group for centrosymmetric gauge transformations of the dynamic motion for a Markov-ordered polymer chain

    International Nuclear Information System (INIS)

    Mikhailov, I.D.; Zhuravskii, L.V.

    1987-01-01

    A method is proposed for calculating the vibrational-state density averaged over all configurations for a polymer chain with Markov disorder. The method is based on using a group of centrally symmetric gauge transformations that reduce the dynamic matrix for along polymer chain to renormalized dynamic matrices for short fragments. The short-range order is incorporated exactly in the averaging procedure, while the long-range order is incorporated in the self-consistent field approximation. Results are given for a simple skeletal model for a polymer containing tacticity deviations of Markov type

  12. Issues Related to the Frequency of Exploratory Analyses by Evidence Review Groups in the NICE Single Technology Appraisal Process.

    Science.gov (United States)

    Kaltenthaler, Eva; Carroll, Christopher; Hill-McManus, Daniel; Scope, Alison; Holmes, Michael; Rice, Stephen; Rose, Micah; Tappenden, Paul; Woolacott, Nerys

    2017-06-01

    Evidence Review Groups (ERGs) critically appraise company submissions as part of the National Institute for Health and Care Excellence (NICE) Single Technology Appraisal (STA) process. As part of their critique of the evidence submitted by companies, the ERGs undertake exploratory analyses to explore uncertainties in the company's model. The aim of this study was to explore pre-defined factors that might influence or predict the extent of ERG exploratory analyses. The aim of this study was to explore predefined factors that might influence or predict the extent of ERG exploratory analyses. We undertook content analysis of over 400 documents, including ERG reports and related documentation for the 100 most recent STAs (2009-2014) for which guidance has been published. Relevant data were extracted from the documents and narrative synthesis was used to summarise the extracted data. All data were extracted and checked by two researchers. Forty different companies submitted documents as part of the NICE STA process. The most common disease area covered by the STAs was cancer (44%), and most ERG reports (n = 93) contained at least one exploratory analysis. The incidence and frequency of ERG exploratory analyses does not appear to be related to any developments in the appraisal process, the disease area covered by the STA, or the company's base-case incremental cost-effectiveness ratio (ICER). However, there does appear to be a pattern in the mean number of analyses conducted by particular ERGs, but the reasons for this are unclear and potentially complex. No clear patterns were identified regarding the presence or frequency of exploratory analyses, apart from the mean number conducted by individual ERGs. More research is needed to understand this relationship.

  13. Hydration of Hydroxyl and Amino Groups Examined by Molecular Dynamics and Neutron Scattering

    Czech Academy of Sciences Publication Activity Database

    Hladílková, Jana; Fischer, H. E.; Jungwirth, Pavel; Mason, Philip E.

    2015-01-01

    Roč. 119, č. 21 (2015), s. 6357-6365 ISSN 1520-6106 R&D Projects: GA ČR GBP208/12/G016 Institutional support: RVO:61388963 Keywords : neutron scattering * molecular dynamics * isopropyl alcohol * isopropylamine Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.187, year: 2015

  14. Ongoing Analyses of Rocket Based Combined Cycle Engines by the Applied Fluid Dynamics Analysis Group at Marshall Space Flight Center

    Science.gov (United States)

    Ruf, Joseph H.; Holt, James B.; Canabal, Francisco

    2001-01-01

    This paper presents the status of analyses on three Rocket Based Combined Cycle (RBCC) configurations underway in the Applied Fluid Dynamics Analysis Group (TD64). TD64 is performing computational fluid dynamics (CFD) analysis on a Penn State RBCC test rig, the proposed Draco axisymmetric RBCC engine and the Trailblazer engine. The intent of the analysis on the Penn State test rig is to benchmark the Finite Difference Navier Stokes (FDNS) code for ejector mode fluid dynamics. The Draco analysis was a trade study to determine the ejector mode performance as a function of three engine design variables. The Trailblazer analysis is to evaluate the nozzle performance in scramjet mode. Results to date of each analysis are presented.

  15. Ongoing Analysis of Rocket Based Combined Cycle Engines by the Applied Fluid Dynamics Analysis Group at Marshall Space Flight Center

    Science.gov (United States)

    Ruf, Joseph; Holt, James B.; Canabal, Francisco

    1999-01-01

    This paper presents the status of analyses on three Rocket Based Combined Cycle configurations underway in the Applied Fluid Dynamics Analysis Group (TD64). TD64 is performing computational fluid dynamics analysis on a Penn State RBCC test rig, the proposed Draco axisymmetric RBCC engine and the Trailblazer engine. The intent of the analysis on the Penn State test rig is to benchmark the Finite Difference Navier Stokes code for ejector mode fluid dynamics. The Draco engine analysis is a trade study to determine the ejector mode performance as a function of three engine design variables. The Trailblazer analysis is to evaluate the nozzle performance in scramjet mode. Results to date of each analysis are presented.

  16. Generic features of the dynamics of complex open quantum systems: statistical approach based on averages over the unitary group.

    Science.gov (United States)

    Gessner, Manuel; Breuer, Heinz-Peter

    2013-04-01

    We obtain exact analytic expressions for a class of functions expressed as integrals over the Haar measure of the unitary group in d dimensions. Based on these general mathematical results, we investigate generic dynamical properties of complex open quantum systems, employing arguments from ensemble theory. We further generalize these results to arbitrary eigenvalue distributions, allowing a detailed comparison of typical regular and chaotic systems with the help of concepts from random matrix theory. To illustrate the physical relevance and the general applicability of our results we present a series of examples related to the fields of open quantum systems and nonequilibrium quantum thermodynamics. These include the effect of initial correlations, the average quantum dynamical maps, the generic dynamics of system-environment pure state entanglement and, finally, the equilibration of generic open and closed quantum systems.

  17. Critical Dynamics of the Xy-Model on the One-Dimensional Superlattice by Position Space Renormalization Group

    Science.gov (United States)

    Lima, J. P. De; Gonçalves, L. L.

    The critical dynamics of the isotropic XY-model on the one-dimensional superlattice is considered in the framework of the position space renormalization group theory. The decimation transformation is introduced by considering the equations of motion of the operators associated to the excitations of the system, and it corresponds to an extension of the procedure introduced by Stinchcombe and dos Santos (J. Phys. A18, L597 (1985)) for the homogeneous lattice. The dispersion relation is obtained exactly and the static and dynamic scaling forms are explicitly determined. The dynamic critical exponent is also obtained and it is shown that it is identical to the one of the XY-model on the homogeneous chain.

  18. Dynamic online peer evaluations to improve group assignments in nursing e-learning environment.

    Science.gov (United States)

    Adwan, Jehad

    2016-06-01

    The purpose of this research was to evaluate the use of online peer evaluation forms for online group activities in improving group project outcomes. The investigator developed and used a web-based Google Forms® self and peer evaluation form of 2 group assignments' rubric for junior and senior nursing students. The form covered elements of the assignments including: research activity, analysis of the literature, writing of report, participation in making of presentation, overall contribution to the project, and participation in the weekly group discussions. Items were rated from 1 (did not contribute) to 5 (outstanding contribution) in addition to NA when one activity did not apply. The self and peer evaluation process was conducted twice: once after group assignment 1 and once after group assignment 2. The group assignments final products were done in the form of VoiceThread online presentations that were shared with the rest of the class reflecting the groups' work on a health informatics topic of interest. Data collected as the students completed self and peer evaluations for group assignments 1 and 2. Also, optional comments regarding member performance were collected to add contextual information in addition to ratings. Students received credit for completing the peer evaluations and the grade for the particular assignment was affected by their performance based on peer evaluations of their contributions. Students' peer evaluations showed in a color-coded spreadsheet which enabled the course faculty to view real time results of students' ratings after each assignment. The faculty provided timely and tailored feedback to groups or individuals as needed, using positive feedback and commending high performance while urging struggling individual students and groups to improve lower ratings in specific areas. Comparing evaluations of both assignments, there were statistically significant improvements among all students. The mean scores of the entire sample were

  19. Complex Dynamical Behaviors in a Predator-Prey System with Generalized Group Defense and Impulsive Control Strategy

    Directory of Open Access Journals (Sweden)

    Shunyi Li

    2013-01-01

    Full Text Available A predator-prey system with generalized group defense and impulsive control strategy is investigated. By using Floquet theorem and small amplitude perturbation skills, a local asymptotically stable prey-eradication periodic solution is obtained when the impulsive period is less than some critical value. Otherwise, the system is permanent if the impulsive period is larger than the critical value. By using bifurcation theory, we show the existence and stability of positive periodic solution when the pest eradication lost its stability. Numerical examples show that the system considered has more complicated dynamics, including (1 high-order quasiperiodic and periodic oscillation, (2 period-doubling and halving bifurcation, (3 nonunique dynamics (meaning that several attractors coexist, and (4 chaos and attractor crisis. Further, the importance of the impulsive period, the released amount of mature predators and the degree of group defense effect are discussed. Finally, the biological implications of the results and the impulsive control strategy are discussed.

  20. Assessing the Internal Dynamics of Mathematical Problem Solving in Small Groups.

    Science.gov (United States)

    Artzt, Alice F.; Armour-Thomas, Eleanor

    The purpose of this exploratory study was to examine the problem-solving behaviors and perceptions of (n=27) seventh-grade students as they worked on solving a mathematical problem within a small-group setting. An assessment system was developed that allowed for this analysis. To assess problem-solving behaviors within a small group a Group…

  1. Effect of Acetyl Group on Mechanical Properties of Chitin/Chitosan Nanocrystal: A Molecular Dynamics Study

    Directory of Open Access Journals (Sweden)

    Junhe Cui

    2016-01-01

    Full Text Available Chitin fiber is the load-bearing component in natural chitin-based materials. In these materials, chitin is always partially deacetylated to different levels, leading to diverse material properties. In order to understand how the acetyl group enhances the fracture resistance capability of chitin fiber, we constructed atomistic models of chitin with varied acetylation degree and analyzed the hydrogen bonding pattern, fracture, and stress-strain behavior of these models. We notice that the acetyl group can contribute to the formation of hydrogen bonds that can stabilize the crystalline structure. In addition, it is found that the specimen with a higher acetylation degree presents a greater resistance against fracture. This study describes the role of the functional group, acetyl groups, in crystalline chitin. Such information could provide preliminary understanding of nanomaterials when similar functional groups are encountered.

  2. S-Lagrangian dynamics of many-body systems and behavior of social groups: Dominance and hierarchy formation

    Science.gov (United States)

    Sandler, U.

    2017-11-01

    In this paper, we extend our generalized Lagrangian dynamics (i.e., S-Lagrangian dynamics, which can be applied equally to physical and non-physical systems as per Sandler (2014)) to many-body systems. Unlike common Lagrangian dynamics, this is not a trivial task. For many-body systems with S-dependent Lagrangians, the Lagrangian and the corresponding Hamiltonian or energy become vector functions, conjugated momenta become second-order tensors, and the system inevitably develops a hierarchical structure, even if all bodies initially have similar status and Lagrangians. As an application of our theory, we consider dominance and hierarchy formation, which is present in almost all communities of living species. As a biological basis for this application, we assume that the primary motivation of a groups activity is to attempt to cope with stress arising as pressure from the environment and from intrinsic unmet needs of individuals. It has been shown that the S-Lagrangian approach to a group's evolution naturally leads to formation of linear or despotic dominance hierarchies, depending on differences between individuals in coping with stress. That is, individuals that cope more readily with stress take leadership roles during the evolution. Experimental results in animal groups which support our assumption and findings are considered.

  3. Statics and dynamics of free and hydrogen-bonded OH groups at the air/water interface.

    Science.gov (United States)

    Vila Verde, Ana; Bolhuis, Peter G; Campen, R Kramer

    2012-08-09

    We use classical atomistic molecular dynamics simulations of two water models (SPC/E and TIP4P/2005) to investigate the orientation and reorientation dynamics of two subpopulations of OH groups belonging to water molecules at the air/water interface at 300 K: those OH groups that donate a hydrogen bond (called "bonded") and those that do not (called "free"). Free interfacial OH groups reorient in two distinct regimes: a fast regime from 0 to 1 ps and a slow regime thereafter. Qualitatively similar behavior was reported by others for free OH groups near extended hydrophobic surfaces. In contrast, the net reorientation of bonded OH groups occurs at a rate similar to that of bulk water. This similarity in reorientation rate results from compensation of two effects: decreasing frequency of hydrogen-bond breaking/formation (i.e., hydrogen-bond exchange) and faster rotation of intact hydrogen bonds. Both changes result from the decrease in density at the air/water interface relative to the bulk. Interestingly, because of the presence of capillary waves, the slowdown of hydrogen-bond exchange is significantly smaller than that reported for water near extended hydrophobic surfaces, but it is almost identical to that reported for water near small hydrophobic solutes. In this sense water at the air/water interface has characteristics of water of hydration of both small and extended hydrophobic solutes.

  4. Critical operator actions: human reliability modeling and data issues. Principal Working Group No. 5 - Task 94-1. Final Task Report prepared by a Group of Experts of the NEA Committee on the Safety of Nuclear Installations

    International Nuclear Information System (INIS)

    Wilmart, P.; Grant, A.; Raina, V.M.; Patrik, M.; Cacciabue, P.C.; Cojazzi, G.; Reiman, L.; Virolainen, R.; Lanore, J.M.; Poidevin, S.; Herttrich, P.M.; Mertens, J.; Reer, B.; Straeter, O.; Bareith, A.; Hollo, E.; Traini, E.; Fukuda, M.; Hirano, M.; Kani, Y.; Muramatsu, K.; Versteeg, M.F.; Kim, T.W.; Calvo, J.; Gil, B.; Dang, V.N.; Hirschberg, S.; Meyer, P.; Schmocker, U.; Andrews, R.; Coxson, B.; Shepherd, C.H.; Murphy, J.A.; Parry, G.W.; Ramey-Smith, A.; Siu, N.O.

    1998-01-01

    The treatment of human interactions is considered one of the major limitations in the context of Probabilistic Safety Assessment (PSA).While the results of many PSAs show a very significant contribution of human errors, large uncertainties are normally associated with the quantitative estimates of these contributors. This problem becomes even more significant when analysing human interactions under special conditions, for example in accident scenarios for external events or for the shutdown and low power conditions. Any improvement in the current state of knowledge with respect to the data for human interactions would have a positive impact on the confidence in PSA results, including correct ranking of the dominant accident scenarios. At the same time many PSAs have been successful at identifying critical operator actions; in most cases the benefits of these qualitative insights are not jeopardised by lack of numerical precision in the estimates. The present HRA approaches as generally applied in PSAs are also limited in scope; for instance, they either ignore errors of commissions or treat these superficially. New, dynamic methods, primarily aiming at the resolution of the issues of cognitive errors including errors of commission are emerging but their full-scope applications within the PSA framework belong to the future. In the context of data, some progress has been observed partially due to use of simulators to support the human reliability analysis (HRA). These applications have been rather concentrated (but not limited) to France and USA. Recently, a very promising program has been established in Hungary. The experiences from such applications are not widely known and dissemination of the relevant insights to the PSA community has some definite merits. With respect to the identification of critical operator actions there is in some cases clear evidence and in others a good potential that the existing PSA studies may provide useful, partially generic

  5. Blue Whale (Balaenoptera musculus Behavior and Group Dynamics as Observed from an Aircraft off Southern California

    Directory of Open Access Journals (Sweden)

    Kate Lomac-MacNair

    2016-02-01

    Full Text Available Group behavior and interactions of endangered blue whales (Balaenoptera musculus have not been systematically studied. Such behavioral data are often overlooked when assessing anthropogenic effects. Yet behavioral data are necessary to compare “normal” behaviors with behavior affected by anthropogenic factors of concern relative to effective management and recovery of blue whales. For a baseline study, we hypothesized that the response variables sighting rate, group size, calf presence and group cohesion (i.e., spacing between individuals within a group differed according to the spatio-temporal explanatory variables behavioral state, time of day, season, water depth and distance from shore. To address our hypotheses, we flew systematic line transect surveys in southern California and collected focal group data. Two sets of data were separately analyzed using different sampling approaches: (1 point sample data associated with the first sighting of a blue whale(s, and (2 extended all-occurrence focal group behavioral sampling data (i.e., focal follows collected on a subsample of all sightings while the aircraft circled at a radial distance of approximately 0.5-1 km and an altitude of 1,500 m for extended periods of 5 – 60 minutes. Chi-square contingency table and G² analyses were used to assess statistical relationships between response and explanatory variables. We conducted 18 one-week-long aerial surveys spanning October 2008 through May 2013 (at least once during every month except December, totaling 87,555 km of observation effort. Seventy blue whale sightings (117 individuals were seen, ranging in size from 1 – 6 whales, and focal follow was performed on over half (55% of these sightings. Results supported our hypotheses that blue whale group characteristics were related to behavioral state and spatio-temporal variables. Sighting rates were significantly highest during summer followed by spring, fall, and winter. Group type differed

  6. Group formation in a public good experiment: on the dynamics of social ties structures

    NARCIS (Netherlands)

    Sonnemans, J.H.; van Dijk, F.; van Winden, F.A.A.M.

    1999-01-01

    Economic behavior often takes place in groups of small numbers of peopleinteracting with each other (like work teams, neighborhoods, socialnetworks, etc.). Characteristic of such interaction is the development of(affective) interpersonal relationships, or social ties. According tosociologists, the

  7. Gauge invariance over a group as the first principle of interacting string dynamics

    International Nuclear Information System (INIS)

    Gervais, J.L.

    1986-01-01

    It is stressed that the basic principle of the standard gauge theories is the invariance under internal symmetry transformations that do not commute with translations. This concept is generalized to the case where the translation group is replaced by an arbitrarily given non-abelian group G. The generalized Yang-Mills theory, called gauge theory over G, is an attractive extension of the standard formalism. The gauge theory over the conformal group is proposed as the fundamental theory of bosonic strings. As is usual in gauge theories, the interaction is uniquely specific by the invariance properties. For strings, overlap conditions between string positions come out in a natural way. The powerful machinery of Yang-Mills theories is fully applicable to the gauge theories over groups. In particular, an example of the Higgs-Kibble mechanism is given. (orig.)

  8. Fixed geometric formation structure in formation control problem for group of robots with dynamically changing number of robots in the group

    Directory of Open Access Journals (Sweden)

    N. S. Morozova

    2015-01-01

    Full Text Available The article considers a problem of the decentralization-based approach to formation control of a group of agents, which simulate mobile autonomous robots. The agents use only local information limited by the covering range of their sensors. The agents have to build and maintain the formation, which fits to the defined target geometric formation structure with desired accuracy during the movement to the target point. At any point in time the number of agents in the group can change unexpectedly (for example, as a result of the agent failure or if a new agent joins the group.The aim of the article is to provide the base control rule, which solves the formation control problem, and to develop its modifications, which provide the correct behavior in case the agent number in the group is not equal to the size of the target geometric formation structure. The proposed base control rule, developed by the author, uses the method of involving virtual leaders. The coordinates of the virtual leaders and also the priority to follow the specific leader are calculated by each agent itself according to specific rules.The following results are presented in the article: the base control rule for solving the formation control problem, its modifications for the cases when the number of agents is greater/less than the size of the target geometric formation structure and also the computer modeling results proving the efficiency of the modified control rules. The specific feature of the control rule, developed by the author, is that each agent itself calculates the virtual leaders and each agent performs dynamic choice of the place within the formation (there is no predefined one-to-one relation between agents and places within the geometric formation structure. The results, provided in this article, can be used in robotics for developing control algorithms for the tasks, which require preserving specific relational positions among the agents while moving. One of the

  9. A Dynamic Active Multicast Group Access Control Framework Based on Trust Management System

    Institute of Scientific and Technical Information of China (English)

    YANG Chang; CHEN Xiaolin; ZHANG Huanguo

    2006-01-01

    The current multicast model provides no access control mechanism. Any host can send data directly to a multicast address or join a multicast group to become a member, which brings safety problems to multicast. In this paper, we present a new active multicast group access control mechanism that is founded on trust management. This structure can solve the problem that exists in multicast members' access control and distributing authorization of traditional IP multicast.

  10. Results of the Workshop on Two-Phase Flow, Fluid Stability and Dynamics: Issues in Power, Propulsion, and Advanced Life Support Systems

    Science.gov (United States)

    McQuillen, John; Rame, Enrique; Kassemi, Mohammad; Singh, Bhim; Motil, Brian

    2003-01-01

    The Two-phase Flow, Fluid Stability and Dynamics Workshop was held on May 15, 2003 in Cleveland, Ohio to define a coherent scientific research plan and roadmap that addresses the multiphase fluid problems associated with NASA s technology development program. The workshop participants, from academia, industry and government, prioritized various multiphase issues and generated a research plan and roadmap to resolve them. This report presents a prioritization of the various multiphase flow and fluid stability phenomena related primarily to power, propulsion, fluid and thermal management and advanced life support; and a plan to address these issues in a logical and timely fashion using analysis, ground-based and space-flight experiments.

  11. Modelling of the turbo-generator groups dynamical behaviour. Application to the ARABELLE turbine of the N4 1400 MW unit

    International Nuclear Information System (INIS)

    Bediou, J.

    1993-01-01

    Simulation of the dynamical behaviour of the EDF turbogenerator groups is based on developments concerning bearing behaviour and shaft line dynamics. A provisional model for the ARABELLE turbine dynamic behaviour is derived. The detailed representation of all the components allows for a fine analysis of the different effects and the evaluation of the stresses transmitted to the structure in anomalistic operating conditions

  12. [?]Nonlinear Issues in the Aerothermochemistry of Gases and Materials and the Associated Physics and Dynamics of Interfaces

    Science.gov (United States)

    Johnson, Joseph A., III

    1996-01-01

    Our research and technology are focused on nonlinear issues in the aerothermochemistry of gases and materials and the associated physics and dynamics of interfaces. Our program is now organized to aggressively support the NASA Aeronautics Enterprise so as to: (a) develop a new generation of environmentally compatible, economic subsonic aircraft; (b) develop the technology base for an economically viable and environmentally compatible high-speed civil transport; (c) develop the technology options for new capabilities in high-performance aircraft; (d) develop hypersonic technologies for air-breathing flight; and (e) develop advanced concepts, understanding of physical phenomena, and theoretical, experimental, and computational tools for advanced aerospace systems. The implications from our research for aeronautical and aerospace technology have been both broad and deep. For example, using advanced computational techniques, we have determined exact solutions for the Schrodinger equation in electron-molecule scattering allowing us to evaluate atmospheric models important to reentry physics. We have also found a new class of exact solutions for the Navier Stokes equations. In experimental fluid dynamics, we have found explicit evidence of turbulence modification of droplet sizes in shock tube flow with condensation. We have developed a new diagnostic tool for the direct estimation of flow velocities at MHz sampling rates in quasi-one dimensional turbulent flow. This procedure suggests an unexpected confirmation of the possibility of 'natural' closure in Reynolds stresses with deep implications for the development of turbulent models. A transient increase is observed in both the spectral energy decay rate and the degree of chaotic complexity at the interface of a shock wave and a turbulent ionized gas. Even though the gas is apparently brought to rest by the shock wave, no evidence is found either of the expected relaminarization. A unique diamond-shaped nozzle has been

  13. Renormalization group flows in σ-models coupled to two-dimensional dynamical gravity

    International Nuclear Information System (INIS)

    Penati, S.; Santambrogio, A.; Zanon, D.

    1997-01-01

    We consider a bosonic σ-model coupled to two-dimensional gravity. In the semiclassical limit, c→-∞, we compute the gravity dressing of the β-functions at two-loop order in the matter fields. We find that the corrections due to the presence of dynamical gravity are not expressible simply in terms of a multiplicative factor as previously obtained at the one-loop level. Our result indicates that the critical points of the theory are non-trivially influenced and modified by the induced gravity. (orig.)

  14. Dynamical generation of non-abelian gauge group via the improved perturbation theory

    International Nuclear Information System (INIS)

    Kuroki, Tsunehide

    2008-01-01

    It was suggested that the massive Yang-Mills-Chern-Simons matrix model has three phases and that in one of them a non-Abelian gauge symmetry is dynamically generated. The analysis was at the one-loop level around a classical solution of fuzzy sphere type. We obtain evidences that three phases are indeed realized as nonperturbative vacua by using the improved perturbation theory. It gives a good example that even if we start from a trivial vacuum, the improved perturbation theory around it enables us to observe nontrivial vacua. (author)

  15. An overview of the formulation, existence and uniqueness issues for the initial value problem raised by the dynamics of discrete systems with unilateral contact and dry friction

    Science.gov (United States)

    Ballard, Patrick; Charles, Alexandre

    2018-03-01

    In the end of the seventies, Schatzman and Moreau undertook to revisit the venerable dynamics of rigid bodies with contact and dry friction in the light of more recent mathematics. One claimed objective was to reach, for the first time, a mathematically consistent formulation of an initial value problem associated with the dynamics. The purpose of this article is to make a review of the today state-of-art concerning not only the formulation, but also the issues of existence and uniqueness of solution. xml:lang="fr"

  16. Group Psychotherapy in Denmark.

    Science.gov (United States)

    Jørgensen, Lars Bo; Thygesen, Bente; Aagaard, Søren

    2015-10-01

    This is a short article on the history and training standards in the Institute of Group Analysis in Copenhagen (IGA-CPH). We describe theoretical orientations and influences in the long-term training program and new initiatives, like courses in mentalization-based group treatment and a dynamic short-term group therapy course, as well as research in group psychotherapy in Denmark. Some group analytic initiatives in relation to social issues and social welfare are presented, as well as initiatives concerning the school system and unemployment.

  17. Utility rate equations of group population dynamics in biological and social systems.

    Directory of Open Access Journals (Sweden)

    Vyacheslav I Yukalov

    Full Text Available We present a novel system of equations to describe the evolution of self-organized structured societies (biological or human composed of several trait groups. The suggested approach is based on the combination of ideas employed in the theory of biological populations, system theory, and utility theory. The evolution equations are defined as utility rate equations, whose parameters are characterized by the utility of each group with respect to the society as a whole and by the mutual utilities of groups with respect to each other. We analyze in detail the cases of two groups (cooperators and defectors and of three groups (cooperators, defectors, and regulators and find that, in a self-organized society, neither defectors nor regulators can overpass the maximal fractions of about [Formula: see text] each. This is in agreement with the data for bee and ant colonies. The classification of societies by their distance from equilibrium is proposed. We apply the formalism to rank the countries according to the introduced metric quantifying their relative stability, which depends on the cost of defectors and regulators as well as their respective population fractions. We find a remarkable concordance with more standard economic ranking based, for instance, on GDP per capita.

  18. Utility Rate Equations of Group Population Dynamics in Biological and Social Systems

    Science.gov (United States)

    Yukalov, Vyacheslav I.; Yukalova, Elizaveta P.; Sornette, Didier

    2013-01-01

    We present a novel system of equations to describe the evolution of self-organized structured societies (biological or human) composed of several trait groups. The suggested approach is based on the combination of ideas employed in the theory of biological populations, system theory, and utility theory. The evolution equations are defined as utility rate equations, whose parameters are characterized by the utility of each group with respect to the society as a whole and by the mutual utilities of groups with respect to each other. We analyze in detail the cases of two groups (cooperators and defectors) and of three groups (cooperators, defectors, and regulators) and find that, in a self-organized society, neither defectors nor regulators can overpass the maximal fractions of about each. This is in agreement with the data for bee and ant colonies. The classification of societies by their distance from equilibrium is proposed. We apply the formalism to rank the countries according to the introduced metric quantifying their relative stability, which depends on the cost of defectors and regulators as well as their respective population fractions. We find a remarkable concordance with more standard economic ranking based, for instance, on GDP per capita. PMID:24386163

  19. Symmetry breaking in fluid dynamics: Lie group reducible motions for real fluids

    International Nuclear Information System (INIS)

    Holm, D.D.

    1976-07-01

    The physics of fluids is based on certain kinematical invariance principles, which refer to coordinate systems, dimensions, and Galilean reference frames. Other, thermodynamic, symmetry principles are introduced by the material description. In the present work, the interplay between these two kinds of invariance principles is used to solve for classes of one-dimensional non-steady isentropic motions of a fluid whose equation of state is of Mie-Gruneisen type. Also, the change in profile and attenuation of weak shock waves in a dissipative medium is studied at the level of Burgers' approximation from the viewpoint of its underlying symmetry structure. The mathematical method of approach is based on the theory of infinitesimal Lie groups. Fluid motions are characterized according to inequivalent subgroups of the full invariance group of the flow description and exact group reducible solutions are presented

  20. Symmetry breaking in fluid dynamics: Lie group reducible motions for real fluids

    Energy Technology Data Exchange (ETDEWEB)

    Holm, D.D.

    1976-07-01

    The physics of fluids is based on certain kinematical invariance principles, which refer to coordinate systems, dimensions, and Galilean reference frames. Other, thermodynamic, symmetry principles are introduced by the material description. In the present work, the interplay between these two kinds of invariance principles is used to solve for classes of one-dimensional non-steady isentropic motions of a fluid whose equation of state is of Mie-Gruneisen type. Also, the change in profile and attenuation of weak shock waves in a dissipative medium is studied at the level of Burgers' approximation from the viewpoint of its underlying symmetry structure. The mathematical method of approach is based on the theory of infinitesimal Lie groups. Fluid motions are characterized according to inequivalent subgroups of the full invariance group of the flow description and exact group reducible solutions are presented.

  1. Detecting concealed information from groups using a dynamic questioning approach: simultaneous skin conductance measurement and immediate feedback

    Directory of Open Access Journals (Sweden)

    Ewout H Meijer

    2013-02-01

    Full Text Available Lie detection procedures typically aim at determining the guilt or innocence of a single suspect. The Concealed Information Test (CIT, for example, has been shown to be highly successful in detecting the presence or absence of crime-related information in a suspect’s memory. Many of today’s security threats, however, do not come from individuals, but from organized groups such as criminal organizations or terrorist networks. In this study, we tested whether a plan of an upcoming mock terrorist attack could be extracted from a group of suspects using a dynamic questioning approach. One-hundred participants were tested in 20 groups of 5. Each group was asked to plan a mock terrorist attack based on a list of potential countries, cities and streets. Next, three questions referring to the country, city, and street were presented, each with 5 options. Skin conductance in all 5 members of the group was measured simultaneously during this presentation. The dynamic questioning approach entailed direct analysis of the data, and if the average skin conductance of the group to a certain option exceeded a threshold, this option was followed up. E.g., if the reaction to the option ‘Italy’ exceeded the threshold, this was followed up by presenting 5 cities in Italy. Results showed that in 19 of the 20 groups the country was correctly detected using this procedure. In 13 of these remaining 19 groups the city was correctly detected. In 7 of these 13, the street was also correctly detected. The question about the country resulted in no false positives (out of 20, the question about the city resulted in 2 false positives (out of 19, while the question about the streets resulted in 2 false positives (out of 13. Furthermore, the 2 false positives at the city level also yielded a false positive at the street level. Taken together these results indicate our dynamic questioning approach can help to unveil plans about a mock terrorist attack.

  2. Tweeting on Catalonia’s Independence: The Dynamics of Political Discussion and Group Polarisation

    Directory of Open Access Journals (Sweden)

    Joan Balcells

    2016-12-01

    Full Text Available This article provides evidence in favour of social media serving as facilitators of public deliberation, in contrast with the hypothesis that emphasises the dominance of the “echo chamber” effect. It focuses on conversational interactions on Twitter between supporters from opposite sides in a potentially highly polarised political issue, i.e. the debate on the independence of Catalonia, which is used as a case study. Methodologically we rely on a random sample of communications on the Twitter reply network, involving for and against independence supporters. Remarkably, despite the tendency of forming homophilic networks, we find that communication across political lines is relatively frequent. Furthermore, heterogeneous conversations (where opposing sides are engaged in a dialogue tend to be significantly longer than homogenous ones (where all participants share the same view, which can be seen as a sign of genuine deliberation based on reasonably exchanging arguments between competing viewpoints.

  3. Issues of knowledge and expertise in policy arrangements: An exploratory case study of the dynamic preservation approach to coastal management

    NARCIS (Netherlands)

    van der Molen, Franke

    2012-01-01

    Since 1990, the Dutch government applies the approach of dynamic preservation to coastal management. One of the characteristics of this approach is that, compared to the old approach, more room is allowed for natural dynamic movement of sand, in order to preserve the coastline, increase coastal

  4. Path integral for coherent states of the dynamical U2 group and U2/1 supergroup

    International Nuclear Information System (INIS)

    Kochetov, E.A.

    1992-01-01

    A part-integral formulation in the representation of coherent states for the unitary U 2 group and U 2/1 supergroup is introduced. U 2 and U 2/1 path integrals are shown to be defined on the coset spaces U 2 /U 1 xU 1 and U 2/1 /U 1/1 xU 1 , respectively. These coset appears as curved classical phase spaces. Partition functions are expressed as path integrals over these spaces. In the case when U 2 and U 2/1 are the dynamical groups, the corresponding path integrals are evaluated with the help of linear fractional transformations that appear as the group (supergroup) action in the coset space (superspace). Possible applications for quantum models are discussed. 9 refs

  5. A Dynamic Combinatorial Approach for Identifying Side Groups that Stabilize DNA-Templated Supramolecular Self-Assemblies

    Directory of Open Access Journals (Sweden)

    Delphine Paolantoni

    2015-02-01

    Full Text Available DNA-templated self-assembly is an emerging strategy for generating functional supramolecular systems, which requires the identification of potent multi-point binding ligands. In this line, we recently showed that bis-functionalized guanidinium compounds can interact with ssDNA and generate a supramolecular complex through the recognition of the phosphodiester backbone of DNA. In order to probe the importance of secondary interactions and to identify side groups that stabilize these DNA-templated self-assemblies, we report herein the implementation of a dynamic combinatorial approach. We used an in situ fragment assembly process based on reductive amination and tested various side groups, including amino acids. The results reveal that aromatic and cationic side groups participate in secondary supramolecular interactions that stabilize the complexes formed with ssDNA.

  6. Dynamics of industrial districts and business groups. The case of the Marche region

    NARCIS (Netherlands)

    Randelli, F.; Boschma, R.A.

    2012-01-01

    Italian industrial districts are undergoing fundamental changes due to globalization. Taking a firm perspective, we argue that the analysis of firm strategies, in particular the rise of business groups, is key to understand the organizational adjustments industrial districts have recently gone

  7. Using a Virtual Class to Demonstrate Computer-Mediated Group Dynamics Concepts

    Science.gov (United States)

    Franz, Timothy M.; Vicker, Lauren A.

    2010-01-01

    We report about an active learning demonstration designed to use a virtual class to present computer-mediated group communication course concepts to show that students can learn about these concepts in a virtual class. We designated 1 class period as a virtual rather than face-to-face class, when class members "attended" virtually using…

  8. Group Tasks, Activities, Dynamics, and Interactions in Collaborative Robotics Projects with Elementary and Middle School Children

    Science.gov (United States)

    Yuen, Timothy T.; Boecking, Melanie; Stone, Jennifer; Tiger, Erin Price; Gomez, Alvaro; Guillen, Adrienne; Arreguin, Analisa

    2014-01-01

    Robotics provide the opportunity for students to bring their individual interests, perspectives and areas of expertise together in order to work collaboratively on real-world science, technology, engineering and mathematics (STEM) problems. This paper examines the nature of collaboration that manifests in groups of elementary and middle school…

  9. Problembased learning as a shared musical journey - group dynamics, communication and creativity

    DEFF Research Database (Denmark)

    Lindvang, Charlotte; Beck, Bolette Daniels

    2015-01-01

    The focus of this paper is how we can facilitate problem based learning (PBL) more creatively. We take a closer look upon the connection between creative processes and social communication in the PBL group including how difficulties in the social interplay may hinder creativity. The paper draws o...

  10. Numerical Study on Dynamic Response of Pile Group Foundation of Geotechnical Centrifuge

    Directory of Open Access Journals (Sweden)

    Mao Quansheng

    2015-01-01

    Full Text Available Based on National Engineering Laboratory for Harbor Engineering Structure-Geotechnical Centrifuge Laboratory construction project, the dynamical response of piles foundation under horizontal-rocking vibration was analyzed by using finite element software Abaqus, and the displacement and stress characteristics of piles were discussed with soil between the piles reinforced by high pressure jet piles. The result indicates that in the operation of the centrifuge, foundation changes of vertical load of center pile are very small; the vertical displacement of the pile head is increasing, the vertical displacement of the pile head is no longer changed until the vibration time reaches 3 times period,; the horizontal load of piles varies with sinusoidal, the horizontal displacement amplitude is increasing, , and the vibration amplitude reaches to fixed value at 2 times vibration period.

  11. Targeting children of substance-using parents with the community-based group intervention TRAMPOLINE: A randomised controlled trial - design, evaluation, recruitment issues

    Science.gov (United States)

    2012-01-01

    Background Children of substance-abusing parents are at risk for developing psychosocial development problems. In Germany it is estimated that approx. 2.65 million children are affected by parental substance abuse or dependence. Only ten percent of them receive treatment when parents are treated. To date, no evaluated programme for children from substance-affected families exists in Germany. The study described in this protocol is designed to test the effectiveness of the group programme TRAMPOLINE for children aged 8-12 years with at least one substance-abusing or -dependent caregiver. The intervention is specifically geared to issues and needs of children from substance-affected families. Methods/Design The effectiveness of the manualised nine-session group programme TRAMPOLINE is tested among N = 218 children from substance-affected families in a multicentre randomised controlled trial. Outpatient counselling facilities across the nation from different settings (rural/urban, Northern/Southern/Eastern/Western regions of the country) will deliver the interventions, as they hold the primary access to the target group in Germany. The control condition is a group programme with the same duration that is not addiction-specific. We expect that participants in the intervention condition will show a significant improvement in the use of adaptive coping strategies (in general and within the family) compared to the control condition as a direct result of the intervention. Data is collected shortly before and after as well as six months after the intervention. Discussion In Germany, the study presented here is the first to develop and evaluate a programme for children of substance-abusing parents. Limitations and strengths are discussed with a special focus on recruitment challenges as they appear to be the most potent threat to feasibility in the difficult-to-access target group at hand (Trial registration: ISRCTN81470784). PMID:22439919

  12. Targeting children of substance-using parents with the community-based group intervention TRAMPOLINE: A randomised controlled trial - design, evaluation, recruitment issues

    Directory of Open Access Journals (Sweden)

    Bröning Sonja

    2012-03-01

    Full Text Available Abstract Background Children of substance-abusing parents are at risk for developing psychosocial development problems. In Germany it is estimated that approx. 2.65 million children are affected by parental substance abuse or dependence. Only ten percent of them receive treatment when parents are treated. To date, no evaluated programme for children from substance-affected families exists in Germany. The study described in this protocol is designed to test the effectiveness of the group programme TRAMPOLINE for children aged 8-12 years with at least one substance-abusing or -dependent caregiver. The intervention is specifically geared to issues and needs of children from substance-affected families. Methods/Design The effectiveness of the manualised nine-session group programme TRAMPOLINE is tested among N = 218 children from substance-affected families in a multicentre randomised controlled trial. Outpatient counselling facilities across the nation from different settings (rural/urban, Northern/Southern/Eastern/Western regions of the country will deliver the interventions, as they hold the primary access to the target group in Germany. The control condition is a group programme with the same duration that is not addiction-specific. We expect that participants in the intervention condition will show a significant improvement in the use of adaptive coping strategies (in general and within the family compared to the control condition as a direct result of the intervention. Data is collected shortly before and after as well as six months after the intervention. Discussion In Germany, the study presented here is the first to develop and evaluate a programme for children of substance-abusing parents. Limitations and strengths are discussed with a special focus on recruitment challenges as they appear to be the most potent threat to feasibility in the difficult-to-access target group at hand (Trial registration: ISRCTN81470784.

  13. Targeting children of substance-using parents with the community-based group intervention TRAMPOLINE: a randomised controlled trial--design, evaluation, recruitment issues.

    Science.gov (United States)

    Bröning, Sonja; Wiedow, Annika; Wartberg, Lutz; Ruths, Sylvia; Haevelmann, Andrea; Kindermann, Sally-Sophie; Moesgen, Diana; Schaunig-Busch, Ines; Klein, Michael; Thomasius, Rainer

    2012-03-22

    Children of substance-abusing parents are at risk for developing psychosocial development problems. In Germany it is estimated that approx. 2.65 million children are affected by parental substance abuse or dependence. Only ten percent of them receive treatment when parents are treated. To date, no evaluated programme for children from substance-affected families exists in Germany. The study described in this protocol is designed to test the effectiveness of the group programme TRAMPOLINE for children aged 8-12 years with at least one substance-abusing or -dependent caregiver. The intervention is specifically geared to issues and needs of children from substance-affected families. The effectiveness of the manualised nine-session group programme TRAMPOLINE is tested among N = 218 children from substance-affected families in a multicentre randomised controlled trial. Outpatient counselling facilities across the nation from different settings (rural/urban, Northern/Southern/Eastern/Western regions of the country) will deliver the interventions, as they hold the primary access to the target group in Germany. The control condition is a group programme with the same duration that is not addiction-specific. We expect that participants in the intervention condition will show a significant improvement in the use of adaptive coping strategies (in general and within the family) compared to the control condition as a direct result of the intervention. Data is collected shortly before and after as well as six months after the intervention. In Germany, the study presented here is the first to develop and evaluate a programme for children of substance-abusing parents. Limitations and strengths are discussed with a special focus on recruitment challenges as they appear to be the most potent threat to feasibility in the difficult-to-access target group at hand (Trial registration: ISRCTN81470784).

  14. Advantaged group's emotional reactions to intergroup inequality: the dynamics of pride, guilt, and sympathy.

    Science.gov (United States)

    Harth, Nicole Syringa; Kessler, Thomas; Leach, Colin Wayne

    2008-01-01

    Three studies establish intergroup inequality to investigate how it is emotionally experienced by the advantaged. Studies 1 and 2 examine psychology students' emotional experience of their unequal job situation with worse-off pedagogy students. When inequality is ingroup focused and legitimate, participants experience more pride. However, when inequality is ingroup focused and illegitimate, participants experience more guilt. Sympathy is increased when inequality is outgroup focused and illegitimate. These emotions have particular effects on behavioral tendencies. In Study 2 group-based pride predicts greater ingroup favoritism in a resource distribution task, whereas group-based sympathy predicts less ingroup favoritism. Study 3 replicates these findings in the context of students' willingness to let young immigrants take part in a university sport. Pride predicts less willingness to let immigrants take part whereas sympathy predicts greater willingness. Guilt is a weak predictor of behavioral tendencies in all studies. This shows the specificity of emotions experienced about intergroup inequality.

  15. Comparative dynamic analysis of morbidity in various age groups in Russian Federation

    Directory of Open Access Journals (Sweden)

    Vera A. Pogodina

    2016-09-01

    Conclusion ― Rate of healthcare visits in Russian Federation was higher for children aged 0-14 years and population older than 18 years. Morbidity increase rate was higher in children aged 0-14 years and women older than 55 years and men older than 60 years. Structural differences in disease groups were detected, which may be taken into account when planning preventive measures according to population age.

  16. Worker Safety and Health Issues Associated with the DOE Environmental Cleanup Program: Insights From the DOE Laboratory Directors' Environmental and Occupational/Public health Standards Steering Group

    International Nuclear Information System (INIS)

    M.C. Edelson; Samuel C. Morris; Joan M. Daisey

    2001-01-01

    The U.S. Department of Energy (DOE) Laboratory Directors' Environmental and Occupational/Public Health Standards Steering Group (or ''SSG'') was formed in 1990. It was felt then that ''risk'' could be an organizing principle for environmental cleanup and that risk-based cleanup standards could rationalize clean up work. The environmental remediation process puts workers engaged in cleanup activities at risk from hazardous materials and from the more usual hazards associated with construction activities. In a real sense, the site remediation process involves the transfer of a hypothetical risk to the environment and the public from isolated contamination into real risks to the workers engaged in the remediation activities. Late in its existence the SSG, primarily motivated by its LANL representative, Dr. Harry Ettinger, actively investigated issues associated with worker health and safety during environmental remediation activities. This paper summarizes the insights noted by the SSG. Most continue to be pertinent today

  17. Group dynamics and social interaction in a South Asian online learning forum for faculty development of medical teachers.

    Science.gov (United States)

    Anshu; Sharma, M; Burdick, W P; Singh, T

    2010-04-01

    Group dynamics of online medical faculty development programs have not been analyzed and reported in literature. Knowledge of the types of content of posted messages will help to understand group dynamics and promote participation in an asynchronous learning environment. This paper assesses group dynamics and social interactivity in an online learning environment for medical teachers in the South Asian context. Participants of a medical education fellowship program conducted by the Foundation for Advancement of International Medical Education and Research (FAIMER) Regional Institute at Christian Medical College, Ludhiana (CMCL) in India interact on a listserv called the Mentoring-Learning Web (ML-Web). Monthly topics for online discussion are chosen by fellows through a standard tool called "multi-voting". Fellows volunteer to moderate sessions and direct the pace of the discussion. We analyzed the content and process of the discussion of one particular month. The emails were categorized as those that reflected cognitive presence (dealing with construction and exploration of knowledge), teacher presence (dealing with instructional material and learning resources), and social presence, or were administrative in nature. Social emails were further classified as: affective, cohesive and interactive. Social emails constituted one-third of the total emails. Another one-quarter of the emails dealt with sharing of resources and teacher presence, while cognitive emails comprised 36.2% of the total. More than half of the social emails were affective, while a little less than one-third were cohesive. Social posts are an inevitable part of online learning. These posts promote bonding between learners and contribute to better interaction and collaboration in online learning. Moderators should be aware of their presence and use them as tools to promote interactivity.

  18. Social group dynamics predict stress variability among children in a New Zealand classroom.

    Science.gov (United States)

    Spray, Julie; Floyd, Bruce; Littleton, Judith; Trnka, Susanna; Mattison, Siobhan

    2018-03-27

    Previous research proposes stress as a mechanism for linking social environments and biological bodies. In particular, non-human primate studies investigate relationships between cortisol as a measure of stress response and social hierarchies. Because human social structures often include hierarchies of dominance and social status, humans may exhibit similar patterns. Studies of non-human primates, however, have not reached consistent conclusions with respect to relationships between social position and levels of cortisol. While human studies report associations between cortisol and various aspects of social environments, studies that consider social status as a predictor of stress response also report mixed results. Others have argued that perceptions of social status may have different implications for stress response depending upon social context. We propose here that characteristics of children's social networks may be a better predictor of central tendencies and variability of stress response than their perceptions of social status. This is evaluated among 24 children from 9.4 to 11.3 years of age in one upper middle-class New Zealand primary school classroom, assessed through observation within the classroom, self-reports during semi-structured interviews and 221 serial saliva samples provided daily over 10 consecutive school days. A synthetic assessment of the children's networks and peer-relationships was developed prior to saliva-cortisol analysis. We found that greater stability of peer-relationships within groups significantly predicts lower within-group variation in mid-morning cortisol over the two-week period, but not overall within-group differences in mean cortisol. Copyright © 2018 Elsevier GmbH. All rights reserved.

  19. Vibrational Properties of the Phosphate Group Investigated by Molecular Dynamics and Density Functional Theory

    Czech Academy of Sciences Publication Activity Database

    Andrushchenko, Valery; Benda, Ladislav; Páv, Ondřej; Dračínský, Martin; Bouř, Petr

    2015-01-01

    Roč. 119, č. 33 (2015), s. 10682-10692 ISSN 1520-6106 R&D Projects: GA ČR GA13-26526S; GA ČR GAP208/11/0105; GA ČR GA13-03978S; GA ČR GA15-09072S Grant - others:GA AV ČR(CZ) M200550902; GA MŠk(CZ) LM2010005; GA MŠk(CZ) ED3.2.00/08.0144 Institutional support: RVO:61388963 Keywords : DNA phosphate group * vibrational spectroscopy * spectra simulations * MD/DFT Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.187, year: 2015

  20. Basic Science of the Fundamentals and Dynamics of Social-Fringe Group Formation and Sustainment

    Science.gov (United States)

    2012-08-01

    USTIFY! G BELIEFS: WHAT MOTIVATES THE TERRORISTS •:• A 1-’ltmdry l.ist of 1\\lotivations: llonor, Trauma, Religion, llumtli:uion, Sugma, Feminism ...Group Grievance and Humiliation: A Tool in AI-Qaeda Propaganda •Jihad in Algeria today is YOUR hope with permission from Allah in redemption from...relational) and Morality ! 54! "Hear, Israel, the decrees and laws I declare in your hearing today . Learn them and be sure to foLlow them. The

  1. Leadership and management influences on personal and professional development and group dynamics: a student's experience.

    Science.gov (United States)

    Ahmed, Fathima

    2018-03-07

    The ever-evolving nature of nursing requires professionals to keep their knowledge up to date and uphold the Nursing and Midwifery Council (NMC) Code by engaging themselves in ongoing personal and professional development (PPD). This article aims to highlight the importance of good leadership and management in healthcare and to explore the literature surrounding leadership and management, such as the current NHS healthcare leadership model ( NHS Leadership Academy 2013 ), the Leading Change, Adding Value Framework underpinned by the 10 commitments and 6Cs ( NHS England 2016 ) and the NMC Code ( NMC 2015a ) in relation to PPD. It examines how nurses can be supported in their PPD by their team leader and or managers using examples experienced in a clinical setting while caring for children and young people (CYP). Furthermore, the importance of team working and group processes in the context of leadership will be deliberated, using examples of formative group work to illustrate principles described in the literature. Finally, reflections will be discussed on how learning from this experience can influence future practice when caring for CYP. ©2018 RCN Publishing Company Ltd. All rights reserved. Not to be copied, transmitted or recorded in any way, in whole or part, without prior permission of the publishers.

  2. Between-group transmission dynamics of the swallow bug, Oeciacus vicarius.

    Science.gov (United States)

    Brown, Charles R; Brown, Mary Bomberger

    2005-06-01

    The parasitic cimicid swallow bug, Oeciacus vicarius, is the principal invertebrate vector for Buggy Creek virus (BCRV) and has also been associated with Venezuelan equine encephalitis virus. To help understand the spread of this vector, we experimentally measured the transmission of O. vicarius between groups (colonies) of its main host, the cliff swallow (Petrochelidonpyrrhonota), in the field. Transmission of bugs between colonies varied significantly with year, size of the colony, and week within the season. Bug immigration into sites tended to peak in mid-summer. Swallow nests in larger colonies had more consistent rates of bug introduction than did nests in small colonies, but within a colony a given nest's weekly immigrant-bug count varied widely across the season. Transmission of O. vicarius between host social groups follows broadly predictable seasonal patterns, but there is nevertheless temporal and spatial heterogeneity in bug transmission. By understanding how long-distance movement by this vector varies in time and space, we can better predict where and when BCRV epizootics may occur.

  3. Estimating the boundaries of a limit cycle in a 2D dynamical system using renormalization group

    Science.gov (United States)

    Dutta, Ayan; Das, Debapriya; Banerjee, Dhruba; Bhattacharjee, Jayanta K.

    2018-04-01

    While the plausibility of formation of limit cycle has been a well studied topic in context of the Poincare-Bendixson theorem, studies on estimates in regard to the possible size and shape of the limit cycle seem to be scanty in the literature. In this paper we present a pedagogical study of some aspects of the size of this limit cycle using perturbative renormalization group by doing detailed and explicit calculations upto second order for the Selkov model for glycolytic oscillations. This famous model is well known to lead to a limit cycle for certain ranges of values of the parameters involved in the problem. Within the tenets of the approximations made, reasonable agreement with the numerical plots can be achieved.

  4. Planning and managing future space facility projects. [management by objectives and group dynamics

    Science.gov (United States)

    Sieber, J. E.; Wilhelm, J. A.; Tanner, T. A.; Helmreich, R. L.; Burgenbauch, S. F.

    1979-01-01

    To learn how ground-based personnel of a space project plan and organize their work and how such planning and organizing relate to work outcomes, longitudinal study of the management and execution of the Space Lab Mission Development Test 3 (SMD 3) was performed at NASA Ames Research Center. A view of the problems likely to arise in organizations and some methods of coping with these problems are presented as well as the conclusions and recommendations that pertain strictly to SMD 3 management. Emphasis is placed on the broader context of future space facility projects and additional problems that may be anticipated. A model of management that may be used to facilitate problem solving and communication - management by objectives (MBO) is presented. Some problems of communication and emotion management that MBO does not address directly are considered. Models for promoting mature, constructive and satisfying emotional relationships among group members are discussed.

  5. [From quality management to dynamic management through quality: Deployment within a radiotherapy group].

    Science.gov (United States)

    Guerrier, B; Halm, É; Craman, M; Dujols, J-P; Norkowski, J-L; Meynard, K

    2017-10-01

    In 2015, the quality group of the radiotherapy clinic Groupement de Radiothérapie et d'Oncologie des Pyrénées (GROP, Pau, France) decided to review the deployment of its quality approach in order to optimize it continuously. For this, two improvements were proposed: an involvement of process drivers and a material and financial investment in document management software. The implementation of these organizational and managerial provisions enabled us to better cover the requirements of the ISO 9001 standard, the international reference in quality management. Copyright © 2017 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

  6. Full Quantum Dynamics Simulation of a Realistic Molecular System Using the Adaptive Time-Dependent Density Matrix Renormalization Group Method.

    Science.gov (United States)

    Yao, Yao; Sun, Ke-Wei; Luo, Zhen; Ma, Haibo

    2018-01-18

    The accurate theoretical interpretation of ultrafast time-resolved spectroscopy experiments relies on full quantum dynamics simulations for the investigated system, which is nevertheless computationally prohibitive for realistic molecular systems with a large number of electronic and/or vibrational degrees of freedom. In this work, we propose a unitary transformation approach for realistic vibronic Hamiltonians, which can be coped with using the adaptive time-dependent density matrix renormalization group (t-DMRG) method to efficiently evolve the nonadiabatic dynamics of a large molecular system. We demonstrate the accuracy and efficiency of this approach with an example of simulating the exciton dissociation process within an oligothiophene/fullerene heterojunction, indicating that t-DMRG can be a promising method for full quantum dynamics simulation in large chemical systems. Moreover, it is also shown that the proper vibronic features in the ultrafast electronic process can be obtained by simulating the two-dimensional (2D) electronic spectrum by virtue of the high computational efficiency of the t-DMRG method.

  7. Three-dimensional finite element nonlinear dynamic analysis of pile groups for lateral transient and seismic excitations

    International Nuclear Information System (INIS)

    Maheshwari, B.K.; Truman, K.Z.; El Naggar, M.H.; Gould, P.L.

    2004-01-01

    The effects of material nonlinearity of soil and separation at the soil-pile interface on the dynamic behaviour of a single pile and pile groups are investigated. An advanced plasticity-based soil model, hierarchical single surface (HiSS), is incorporated in the finite element formulation. To simulate radiation effects, proper boundary conditions are used. The model and algorithm are verified with analytical results that are available for elastic and elastoplastic soil models. Analyses are performed for seismic excitation and for the load applied on the pile cap. For seismic analysis, both harmonic and transient excitations are considered. For loading on the pile cap, dynamic stiffness of the soil-pile system is derived and the effect of nonlinearity is investigated. The effects of spacing between piles are investigated, and it was found that the effect of soil nonlinearity on the seismic response is very much dependent on the frequency of excitation. For the loading on a pile cap, the nonlinearity increases the response for most of the frequencies of excitation while decreasing the dynamic stiffness of the soil-pile system. (author)

  8. Summary report for MEGAPIE R+D Task Group X4: Fluid dynamics and structure mechanics

    International Nuclear Information System (INIS)

    Smith, B. L.

    2006-03-01

    The document chronicles, and draws summary conclusions from, the activities of the X4 R+D Support Group from the start of the project on January 1, 2000 to the time of the Technical Review Meeting in Mol: 27-29 June, 2005. The objectives to be accomplished were set out in a Baseline document. These were: to define the lower target flow configuration, within the geometric constraints imposed by the physical boundary conditions (geometrical confinement, lead- bismuth eutectic (LBE) inventory, pump capacities, target heat exchanger (THX) power, etc.); to identify, and evaluate, optimum target window design to minimise thermal loads and pressure drops, and to avoid hot-spots and flow instabilities; to demonstrate reliable cooling of the lower target enclosure (LTE); to demonstrate the structural integrity of the lower section of the Iiquid-metal container LMC) and its internal components, and that of the LTE; to provide best-estimate safety margins on target coolability and structural integrity under operational flow conditions; to investigate, quantify, and make recommendations regarding, abnormal target operation including possible accident scenarios). The time-scale set for MEGAPIE was always such that much of the design work needed to be carried out at the same time as the R+D support. Often, the target design was changing faster than the time required to perform the detailed computer simulations. As a consequence, many of the simulations reported or referenced in this document do not refer to the very latest target design, and in many respects the results and conclusions must be regarded as generic in nature. Nonetheless, very valuable work has been carried out by the various organisations, and better understanding of the expected temperature distributions and stress levels in the operating MEGAPIE target has been gained, and direct feed-back to the design team on various aspects of the design details has taken place as a consequence of this work. As the design

  9. Summary report for MEGAPIE R+D Task Group X4: Fluid dynamics and structure mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Smith, B. L

    2006-03-15

    The document chronicles, and draws summary conclusions from, the activities of the X4 R+D Support Group from the start of the project on January 1, 2000 to the time of the Technical Review Meeting in Mol: 27-29 June, 2005. The objectives to be accomplished were set out in a Baseline document. These were: to define the lower target flow configuration, within the geometric constraints imposed by the physical boundary conditions (geometrical confinement, lead- bismuth eutectic (LBE) inventory, pump capacities, target heat exchanger (THX) power, etc.); to identify, and evaluate, optimum target window design to minimise thermal loads and pressure drops, and to avoid hot-spots and flow instabilities; to demonstrate reliable cooling of the lower target enclosure (LTE); to demonstrate the structural integrity of the lower section of the Iiquid-metal container LMC) and its internal components, and that of the LTE; to provide best-estimate safety margins on target coolability and structural integrity under operational flow conditions; to investigate, quantify, and make recommendations regarding, abnormal target operation including possible accident scenarios). The time-scale set for MEGAPIE was always such that much of the design work needed to be carried out at the same time as the R+D support. Often, the target design was changing faster than the time required to perform the detailed computer simulations. As a consequence, many of the simulations reported or referenced in this document do not refer to the very latest target design, and in many respects the results and conclusions must be regarded as generic in nature. Nonetheless, very valuable work has been carried out by the various organisations, and better understanding of the expected temperature distributions and stress levels in the operating MEGAPIE target has been gained, and direct feed-back to the design team on various aspects of the design details has taken place as a consequence of this work. As the design

  10. Violent Dynamics: Exploring Responsibility-Attribution for Harms Inflicted During Spontaneous Group Violence

    Directory of Open Access Journals (Sweden)

    Antje du Bois Pedain

    2016-12-01

    Full Text Available Violent encounters between groups of individuals often leave one or more of the participants dead, and it may be clear from the evidence that the physical cause of death was set by the single, deliberate act of one of the participants only. When this happens, the question arises whether, and how, responsibility for the fatal act and/or for its consequences can be attributed to other participants in the punch-up. Criminal law has long sought – and found – ways of holding others apart from the direct agent responsible for the harms caused in such encounters, although the legal constructions used differ between legal systems and often change significantly over time even within the same jurisdiction. This paper investigates the appropriateness of different criminal-law responses to these cases from two directions: first, by exploring the possible doctrinal grounds within the criminal law for attributing responsibility for the fatal act/outcome to all participants; and then by investigating the extent to which these responsibility-ascriptions are supported or challenged by insights from psychological studies of group action. Los encuentros violentos entre grupos de individuos a menudo acaban con la muerte de uno o más de los participantes, y las pruebas pueden demostrar que la causa física de la muerte fue el acto único deliberado de uno solo de los participantes. Cuando esto ocurre, se plantea la pregunta de si se puede atribuir a otros participantes en la pelea la responsabilidad por el acto fatal y/o sus consecuencias, y cómo hacerlo. Durante mucho tiempo, el derecho penal ha buscado, y encontrado, formas de retener a otros participantes, además del responsable directo de los daños causados, aunque las construcciones legales utilizadas difieren entre sistemas jurídicos y a menudo cambian significativamente a lo largo del tiempo, incluso dentro de la misma jurisdicción. Este artículo investiga la conveniencia de diferentes respuestas

  11. Gas Sloshing and Radio Galaxy Dynamics in the Core of the 3C 449 Group

    Science.gov (United States)

    Lal, Dharam V.; Kraft, Ralph P.; Randall, Scott W.; Forman, William R.; Nulsen, Paul E.; Roediger, Elke; ZuHone, John A.; Hardcastle, Martin J.; Jones, Christine; Croston, Judith H.

    2013-01-01

    We present results from a 140 ks Chandra/ACIS-S observation of the hot gas around the canonical FR I radio galaxy 3C 449. An earlier, shorter 30 ks Chandra observation of the group gas showed an unusual entropy distribution and a surface brightness edge in the gas that could be a strong shock around the inner radio lobes. In our deeper data we find no evidence for a temperature increase inside of the brightness edge, but a temperature decrease across part of the edge. This suggests that the edge is a "sloshing" cold front due to a merger within the last 1.3-1.6 Gyr. Both the northern and southern inner jets are bent slightly to the west in projection as they enter their respective lobes, suggesting that the sloshing core is moving to the east. The straight inner jet flares at approximately the position where it crosses the contact edge, suggesting that the jet is entraining and thermalizing some of the hot gas as it crosses the edge.We also detect filaments of X-ray emission around the southern inner radio jet and lobe which we attribute to low entropy entrained gas. The lobe flaring and gas entrainment were originally predicted in simulations of Loken et al. and are confirmed in our deep observation.

  12. Landau quantized dynamics and spectra for group-VI dichalcogenides, including a model quantum wire

    Science.gov (United States)

    Horing, Norman J. M.

    2017-06-01

    This work is concerned with the derivation of the Green's function for Landau-quantized carriers in the Group-VI dichalcogenides. In the spatially homogeneous case, the Green's function is separated into a Peierls phase factor and a translationally invariant part which is determined in a closed form integral representation involving only elementary functions. The latter is expanded in an eigenfunction series of Laguerre polynomials. These results for the retarded Green's function are presented in both position and momentum representations, and yet another closed form representation is derived in circular coordinates in terms of the Bessel wave function of the second kind (not to be confused with the Bessel function). The case of a quantum wire is also addressed, representing the quantum wire in terms of a model one-dimensional δ (x ) -potential profile. This retarded Green's function for propagation directly along the wire is determined exactly in terms of the corresponding Green's function for the system without the δ (x ) -potential, and the Landau quantized eigenenergy dispersion relation is examined. The thermodynamic Green's function for the dichalcogenide carriers in a normal magnetic field is formulated here in terms of its spectral weight, and its solution is presented in a momentum/integral representation involving only elementary functions, which is subsequently expanded in Laguerre eigenfunctions and presented in both momentum and position representations.

  13. Landau quantized dynamics and spectra for group-VI dichalcogenides, including a model quantum wire

    Directory of Open Access Journals (Sweden)

    Norman J. M. Horing

    2017-06-01

    Full Text Available This work is concerned with the derivation of the Green’s function for Landau-quantized carriers in the Group-VI dichalcogenides. In the spatially homogeneous case, the Green’s function is separated into a Peierls phase factor and a translationally invariant part which is determined in a closed form integral representation involving only elementary functions. The latter is expanded in an eigenfunction series of Laguerre polynomials. These results for the retarded Green’s function are presented in both position and momentum representations, and yet another closed form representation is derived in circular coordinates in terms of the Bessel wave function of the second kind (not to be confused with the Bessel function. The case of a quantum wire is also addressed, representing the quantum wire in terms of a model one-dimensional δ(x-potential profile. This retarded Green’s function for propagation directly along the wire is determined exactly in terms of the corresponding Green’s function for the system without the δ(x-potential, and the Landau quantized eigenenergy dispersion relation is examined. The thermodynamic Green’s function for the dichalcogenide carriers in a normal magnetic field is formulated here in terms of its spectral weight, and its solution is presented in a momentum/integral representation involving only elementary functions, which is subsequently expanded in Laguerre eigenfunctions and presented in both momentum and position representations.

  14. Group dynamics training for manned spaceflight and the capsuls mission: Prophylactic against incompatibility and its consequences?

    Science.gov (United States)

    Kass, R.; Kass, J.

    On February 7, 1994, four Canadian Astronauts were sealed off in a hyperbaric chamber at the Canadian Government's Defense and Civil Institute for Environmental Medicine in Toronto, Canada. This space lab training mission lasted seven days and was the first to be conducted with astronauts outside of Russia. The objective of this mission was to give Canadian astronauts, space scientists and the staff of the Canadian Space Agency (CSA), the opportunity to gain first hand experience on preparational and operational aspects of a typical space mission. Twenty-one scientific experiments involving six countries from several disciplines were involved in this mission. This paper describes the goals and preliminary results of a psychological experiment/training program that used the CAPSULS mission as a test bed for its application in the manned space flight environment. The objective of this project was to enhance the understanding of small group behaviour with a view to maximizing team effectiveness and task accomplishment in teams living and working in isolation under difficult and confined conditions. The application of this model in the light of future missions is a key thesis in this paper.

  15. Dynamic neuronal ensembles: Issues in representing structure change in object-oriented, biologically-based brain models

    Energy Technology Data Exchange (ETDEWEB)

    Vahie, S.; Zeigler, B.P.; Cho, H. [Univ. of Arizona, Tucson, AZ (United States)

    1996-12-31

    This paper describes the structure of dynamic neuronal ensembles (DNEs). DNEs represent a new paradigm for learning, based on biological neural networks that use variable structures. We present a computational neural element that demonstrates biological neuron functionality such as neurotransmitter feedback absolute refractory period and multiple output potentials. More specifically, we will develop a network of neural elements that have the ability to dynamically strengthen, weaken, add and remove interconnections. We demonstrate that the DNE is capable of performing dynamic modifications to neuron connections and exhibiting biological neuron functionality. In addition to its applications for learning, DNEs provide an excellent environment for testing and analysis of biological neural systems. An example of habituation and hyper-sensitization in biological systems, using a neural circuit from a snail is presented and discussed. This paper provides an insight into the DNE paradigm using models developed and simulated in DEVS.

  16. Time development in the early history of social networks: link stabilization, group dynamics, and segregation.

    Science.gov (United States)

    Bruun, Jesper; Bearden, Ian G

    2014-01-01

    Studies of the time development of empirical networks usually investigate late stages where lasting connections have already stabilized. Empirical data on early network history are rare but needed for a better understanding of how social network topology develops in real life. Studying students who are beginning their studies at a university with no or few prior connections to each other offers a unique opportunity to investigate the formation and early development of link patterns and community structure in social networks. During a nine week introductory physics course, first year physics students were asked to identify those with whom they communicated about problem solving in physics during the preceding week. We use these students' self reports to produce time dependent student interaction networks. We investigate these networks to elucidate possible effects of different student attributes in early network formation. Changes in the weekly number of links show that while roughly half of all links change from week to week, students also reestablish a growing number of links as they progress through their first weeks of study. Using the Infomap community detection algorithm, we show that the networks exhibit community structure, and we use non-network student attributes, such as gender and end-of-course grade to characterize communities during their formation. Specifically, we develop a segregation measure and show that students structure themselves according to gender and pre-organized sections (in which students engage in problem solving and laboratory work), but not according to end-of-coure grade. Alluvial diagrams of consecutive weeks' communities show that while student movement between groups are erratic in the beginning of their studies, they stabilize somewhat towards the end of the course. Taken together, the analyses imply that student interaction networks stabilize quickly and that students establish collaborations based on who is immediately

  17. ‘Smart Cities’ – Dynamic Sustainability Issues and Challenges for ‘Old World’ Economies: A Case from the United Kingdom

    Directory of Open Access Journals (Sweden)

    Peter Stokes

    2015-11-01

    Full Text Available The rapid and dynamic rate of urbanization, particularly in emerging world economies, has resulted in a need to find sustainable ways of dealing with the excessive strains and pressures that come to bear on existing infrastructures and relationships. Increasingly during the twenty-first century policy makers have turned to technological solutions to deal with this challenge and the dynamics inherent within it. This move towards the utilization of technology to underpin infrastructure has led to the emergence of the term ‘Smart City’. Smart cities incorporate technology based solutions in their planning development and operation. This paper explores the organizational issues and challenges facing a post-industrial agglomeration in the North West of England as it attempted to become a ‘Smart City’. In particular the paper identifies and discusses the factors that posed significant challenges for the dynamic relationships residents, policymakers and public and private sector organizations and as a result aims to use these micro-level issues to inform the macro-debate and context of wider Smart City discussions. In order to achieve this, the paper develops a range of recommendations that are designed to inform Smart City design, planning and implementation strategies.

  18. Effect of hydrophobic groups on the adsorption conformation of modified polycarboxylate superplasticizer investigated by molecular dynamics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Hongxia [State Key Laboratory of High Performance Civil Engineering Materials, Nanjing 210008, Jiangsu (China); Jiangsu Sobute New Materials Co. Ltd., Nanjing 211103, Jiangsu (China); Wang, Yanwei, E-mail: wangyanwei@cnjsjk.cn [State Key Laboratory of High Performance Civil Engineering Materials, Nanjing 210008, Jiangsu (China); Jiangsu Sobute New Materials Co. Ltd., Nanjing 211103, Jiangsu (China); Yang, Yong; Shu, Xin; Yan, Han [State Key Laboratory of High Performance Civil Engineering Materials, Nanjing 210008, Jiangsu (China); Jiangsu Sobute New Materials Co. Ltd., Nanjing 211103, Jiangsu (China); Ran, Qianping, E-mail: qpran@cnjsjk.cn [State Key Laboratory of High Performance Civil Engineering Materials, Nanjing 210008, Jiangsu (China); Jiangsu Sobute New Materials Co. Ltd., Nanjing 211103, Jiangsu (China)

    2017-06-15

    Highlights: • Adsorption conformation of comb-like PCE was studied by all-atom MD simulations. • A comparison is made between vacuum-based and solution-based simulations. • Effects of hydrophobic modifications on adsorption properties are elucidated. - Abstract: All-atom molecular dynamics (MD) simulations were used to study the adsorption conformations of hydrophobically-modified comb-shaped polycarboxylate ether-based (PCE) superplasticizer molecules on a model surface of dicalcium silicate (C{sub 2}S) in vacuum and in an explicit solution, respectively. Three different hydrophobic modifying groups, namely, the ethyl group, the n-butyl group and the phenyl group, decorated to the backbone, were examined. Comparing the hydrophobically-modified PCEs to the unmodified one, differences were found in the binding energy, the adsorption conformation and the water density at the interface. The interaction between PCE molecules and C{sub 2}S was weakened in a solution with explicit solvents than that obtained from vacuum-based simulations. The presence of hydrophobic groups lowered the polymer-surface binding energy, decreased the radius of gyration (Rg) of the adsorbed polymer, increased the peak position in the heavy-atom density profiles in the direction perpendicular to the surface, and also caused the adsorbed conformations to be more globular in shape. The parallel and perpendicular components (relative to the surface plane) of the geometric sizes of the adsorbed polymers were calculated, and the results showed that the presence of hydrophobically modifying groups decreased the in-plane radius while increased the adsorption layer thickness compared to the unmodified control. The presence of PCEs perturbed the dense water layer above the C{sub 2}S surface and lowered the water density. Perturbations to the interfacial water density were found to correlate nicely with the adsorbed conformations of PCEs.

  19. Group play

    DEFF Research Database (Denmark)

    Tychsen, Anders; Hitchens, Michael; Brolund, Thea

    2008-01-01

    Role-playing games (RPGs) are a well-known game form, existing in a number of formats, including tabletop, live action, and various digital forms. Despite their popularity, empirical studies of these games are relatively rare. In particular there have been few examinations of the effects of the v......Role-playing games (RPGs) are a well-known game form, existing in a number of formats, including tabletop, live action, and various digital forms. Despite their popularity, empirical studies of these games are relatively rare. In particular there have been few examinations of the effects...... of the various formats used by RPGs on the gaming experience. This article presents the results of an empirical study, examining how multi-player tabletop RPGs are affected as they are ported to the digital medium. Issues examined include the use of disposition assessments to predict play experience, the effect...... of group dynamics, the influence of the fictional game characters and the comparative play experience between the two formats. The results indicate that group dynamics and the relationship between the players and their digital characters, are integral to the quality of the gaming experience in multiplayer...

  20. New Frontiers in Heart Rate Variability and Social Coherence Research: Techniques, Technologies, and Implications for Improving Group Dynamics and Outcomes

    Directory of Open Access Journals (Sweden)

    Rollin McCraty

    2017-10-01

    Full Text Available Concepts embraced by the term coherence have been identified as central to fields such as quantum physics, physiology, and social science. There are different types of coherence, although the term always implies a harmonious relationship, correlations and connections between the various parts of a system. A specific measure derived from heart rate variability (HRV provides a measure of physiological coherence. Another type of coherence, social coherence, relates to the harmonious alignment between couples or pairs, family units, small groups, or larger organizations in which a network of relationships exists among individuals who share common interests and objectives. A high degree of social coherence is reflected by stable and harmonious relationships, which allows for the efficient flow and utilization of energy and communication required for optimal collective cohesion and action. Social coherence requires that group members are attuned and are emotionally connected with each other, and that the group’s emotional energy is organized and regulated by the group as a whole. A number of studies are reviewed which have explored various types of synchronization in infants, pairs and groups, indicating that feelings of cooperation, trust, compassion and increased prosocial behaviors depends largely on the establishment of a spontaneous synchronization of various physiological rhythms between individuals. This article discusses a new application using HRV monitoring in social coherence research and the importance of physiological synchronization in group developmental processes and dynamics. Building on the extensive body of research showing that providing feedback of HRV coherence level at the individual level can improve self-regulation, we suggest the following hypotheses: (1 providing feedback of individual and collective HRV coherence and the degree of heart rhythm synchronization will increase group coherence, and heart rhythm synchronization

  1. Modeling and simulation of combustion chamber and propellant dynamics and issues in active control of combustion instabilities

    Science.gov (United States)

    Isella, Giorgio Carlo

    A method for a comprehensive approach to analysis of the dynamics of an actively controlled combustion chamber, with detailed analysis of the combustion models for the case of a solid rocket propellant, is presented here. The objective is to model the system as interconnected blocks describing the dynamics of the chamber, combustion and control. The analytical framework for the analysis of the dynamics of a combustion chamber is based on spatial averaging, as introduced by Culick. Combustion dynamics are analyzed for the case of a solid propellant. Quasi-steady theory is extended to include the dynamics of the gas-phase and also of a surface layer. The models are constructed so that they produce a combustion response function for the solid propellant that can be immediately introduced in the our analytical framework. The principal objective mechanisms responsible for the large sensitivity, observed experimentally, of propellant response to small variations. We show that velocity coupling, and not pressure coupling, has the potential to be the mechanism responsible for that high sensitivity. We also discuss the effect of particulate modeling on the global dynamics of the chamber and revisit the interpretation of the intrinsic stability limit for burning of solid propellants. Active control is also considered. Particular attention is devoted to the effect of time delay (between sensing and actuation); several methods to compensate for it are discussed, with numerical examples based on the approximate analysis produced by our framework. Experimental results are presented for the case of a Dump Combustor. The combustor exhibits an unstable burning mode, defined through the measurement of the pressure trace and shadowgraph imaging. The transition between stable and unstable modes of operation is characterized by the presence of hysteresis, also observed in other experimental works, and hence not a special characteristic of this combustor. Control is introduced in the

  2. Student Leadership in Small Group Science Inquiry

    Science.gov (United States)

    Oliveira, Alandeom W.; Boz, Umit; Broadwell, George A.; Sadler, Troy D.

    2014-01-01

    Background: Science educators have sought to structure collaborative inquiry learning through the assignment of static group roles. This structural approach to student grouping oversimplifies the complexities of peer collaboration and overlooks the highly dynamic nature of group activity. Purpose: This study addresses this issue of…

  3. Microscopic mechanism of amino silicone oil modification and modification effect with different amino group contents based on molecular dynamics simulation

    Science.gov (United States)

    He, Liping; Li, Wenjun; Chen, Dachuan; Yuan, Jianmin; Lu, Gang; Zhou, Dianwu

    2018-05-01

    The microscopic mechanism of amino silicone oil (ASO) modification of natural fiber was investigated for the first time using molecular dynamics (MD) simulation at the atomic and molecular levels. The MD simulation results indicated that the ASO molecular interacted with the cellulose molecular within the natural fiber, mainly by intermolecular forces of Nsbnd Hsbnd O and Osbnd Hsbnd N hydrogen bonds and the molecular chain of ASO absorbed onto the natural fiber in a selective orientation, i.e., the hydrophobic alkyl groups (sbnd CnH2n+1) project outward and the polar amino groups (sbnd NH2) point to the surface of natural fiber. Consequently, the ASO modification changed the surface characteristic of natural fiber from hydrophilic to hydrophobic. Furthermore, the modification effects of the ASO modification layer with different amino group contents (m:n ratio) were also evaluated in this study by calculating the binding energy between the ASO modifier and natural fiber, and the cohesive energy density and free volume of the ASO modification layer. The results showed that the binding energy reached a maximum when the m:n ratio of ASO was of 8:4, suggesting that a good bonding strength was achieved at this m:n ratio. It was also found that the cohesive energy density enhanced with the increase in the amino group content, and the higher the cohesive energy density, the easier the formation of the ASO modification layer. However, the fraction free volume decreased with the increase in the amino group content. This is good for improving the water-proof property of natural fiber. The present work can provide an effective method for predicting the modification effects and designing the optimized m:n ratio of ASO modification.

  4. A close examination of the structure and dynamics of HC(NH2)2PbI3by MD simulations and group theory

    KAUST Repository

    Carignano, M. A.; Saeed, Y.; Aravindh, S. Assa; Roqan, Iman S.; Even, J.; Katan, C.

    2016-01-01

    The formamidinium lead iodide hybrid perovskite is studied using first principles molecular dynamics simulations and further analyzed using group theory. The simulations are performed on large supercells containing 768 atoms under isothermal

  5. Identifying ecological "sweet spots" underlying cyanobacteria functional group dynamics from long-term observations using a statistical machine learning approach

    Science.gov (United States)

    Nelson, N.; Munoz-Carpena, R.; Phlips, E. J.

    2017-12-01

    Diversity in the eco-physiological adaptations of cyanobacteria genera creates challenges for water managers who are tasked with developing appropriate actions for controlling not only the intensity and frequency of cyanobacteria blooms, but also reducing the potential for blooms of harmful taxa (e.g., toxin producers, N2 fixers). Compounding these challenges, the efficacy of nutrient management strategies (phosphorus-only versus nitrogen-and-phosphorus) for cyanobacteria bloom abatement is the subject of an ongoing debate, which increases uncertainty associated with bloom mitigation decision-making. In this work, we analyze a unique long-term (17-year) dataset composed of monthly observations of cyanobacteria genera abundances, zooplankton abundances, water quality, and flow from Lake George, a bloom-impacted flow-through lake of the St. Johns River (FL, USA). Using the Random Forests machine learning algorithm, an assumption-free ensemble modeling approach, the dataset was evaluated to quantify and characterize relationships between environmental conditions and seven cyanobacteria groupings: five genera (Anabaena, Cylindrospermopsis, Lyngbya, Microcystis, and Oscillatoria) and two functional groups (N2 fixers and non-fixers). Results highlight the selectivity of nitrogen in describing genera and functional group dynamics, and potential for physical effects to limit the efficacy of nutrient management as a mechanism for cyanobacteria bloom mitigation.

  6. Dynamic fabric phase sorptive extraction for a group of pharmaceuticals and personal care products from environmental waters.

    Science.gov (United States)

    Lakade, Sameer S; Borrull, Francesc; Furton, Kenneth G; Kabir, Abuzar; Marcé, Rosa Maria; Fontanals, Núria

    2016-07-22

    This paper describes for the first time the use of a new extraction technique, based on fabric phase sorptive extraction (FPSE). This new mode proposes the extraction of the analytes in dynamic mode in order to reduce the extraction time. Dynamic fabric phase sorptive extraction (DFPSE) followed by liquid chromatography-tandem mass spectrometry was evaluated for the extraction of a group of pharmaceuticals and personal care products (PPCPs) from environmental water samples. Different parameters affecting the extraction were optimized and best conditions were achieved when 50mL of sample at pH 3 was passed through 3 disks and analytes retained were eluted with 10mL of ethyl acetate. The recoveries were higher than 60% for most of compounds with the exception of the most polar ones (between 8% and 38%). The analytical method was validated with environmental samples such as river water and effluent and influent wastewater, and good performance was obtained. The analysis of samples revealed the presence of some PPCPs at low ngL(-1) concentrations. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Inclusion of methoxy groups inverts the thermodynamic stabilities of DNA-RNA hybrid duplexes: A molecular dynamics simulation study.

    Science.gov (United States)

    Suresh, Gorle; Priyakumar, U Deva

    2015-09-01

    Modified nucleic acids have found profound applications in nucleic acid based technologies such as antisense and antiviral therapies. Previous studies on chemically modified nucleic acids have suggested that modifications incorporated in furanose sugar especially at 2'-position attribute special properties to nucleic acids when compared to other modifications. 2'-O-methyl modification to deoxyribose sugars of DNA-RNA hybrids is one such modification that increases nucleic acid stability and has become an attractive class of compounds for potential antisense applications. It has been reported that modification of DNA strands with 2'-O-methyl group reverses the thermodynamic stability of DNA-RNA hybrid duplexes. Molecular dynamics simulations have been performed on two hybrid duplexes (DR and RD) which differ from each other and 2'-O-methyl modified counterparts to investigate the effect of 2'-O-methyl modification on their duplex stability. The results obtained suggest that the modification drives the conformations of both the hybrid duplexes towards A-RNA like conformation. The modified hybrid duplexes exhibit significantly contrasting dynamics and hydration patterns compared to respective parent duplexes. In line with the experimental results, the relative binding free energies suggest that the introduced modifications stabilize the less stable DR hybrid, but destabilize the more stable RD duplex. Binding free energy calculations suggest that the increased hydrophobicity is primarily responsible for the reversal of thermodynamic stability of hybrid duplexes. Free energy component analysis further provides insights into the stability of modified duplexes. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. An approach involving dynamic group search optimization for allocating resources in OFDM-based cognitive radio system

    Directory of Open Access Journals (Sweden)

    Sameer Suresh Nanivadekar

    2018-03-01

    Full Text Available Allocation of channel resources in a cognitive radio system for achieving minimized transmission energy at an increased transmission rate is a challenging research. This paper proposes a resource allocation algorithm based on the meta-heuristic search principle. The proposed algorithm is an improved version of the Group Search Optimizer (GSO, which is a currently developed optimization algorithm that works through imitating the searching behaviour of the animals. The improvement is accomplished through introducing dynamics in the maximum pursuit angle of the GSO members. A cognitive radio system, relying on Orthogonal Frequency Division Multiplexing (OFDM for its operation, is simulated and the experimentations are carried out for sub-channel allocation. The proposed algorithm is experimentally compared with five renowned optimization algorithms, namely, conventional GSO, Particle Swarm Optimization, Genetic Algorithm, Firefly Algorithm and Artificial Bee Colony algorithm. The obtained results assert the competing performance of the proposed algorithm over the other algorithms. Keywords: Cognitive radio, OFDM, Resource, Allocation, Optimization, GSO

  9. Intuitionistic Trapezoidal Fuzzy Group Decision-Making Based on Prospect Choquet Integral Operator and Grey Projection Pursuit Dynamic Cluster

    Directory of Open Access Journals (Sweden)

    Jiahang Yuan

    2017-01-01

    Full Text Available In consideration of the interaction among attributes and the influence of decision makers’ risk attitude, this paper proposes an intuitionistic trapezoidal fuzzy aggregation operator based on Choquet integral and prospect theory. With respect to a multiattribute group decision-making problem, the prospect value functions of intuitionistic trapezoidal fuzzy numbers are aggregated by the proposed operator; then a grey relation-projection pursuit dynamic cluster method is developed to obtain the ranking of alternatives; the firefly algorithm is used to optimize the objective function of projection for obtaining the best projection direction of grey correlation projection values, and the grey correlation projection values are evaluated, which are applied to classify, rank, and prefer the alternatives. Finally, an illustrative example is taken in the present study to make the proposed method comprehensible.

  10. Structural dynamics and interactions of Xeroderma pigmentosum complementation group A (XPA98-210) with damaged DNA.

    Science.gov (United States)

    Pradhan, Sushmita; Mattaparthi, Venkata Satish Kumar

    2017-10-25

    Nucleotide excision repair (NER) in higher organisms repair massive DNA abrasions caused by ultraviolet rays, and various mutagens, where Xeroderma pigmentosum group A (XPA) protein is known to be involved in damage recognition step. Any mutations in XPA cause classical Xeroderma pigmentosum disease. The extent to which XPA is required in the NER is still unclear. Here, we present the comparative study on the structural and conformational changes in globular DNA binding domain of XPA 98-210 in DNA bound and DNA free state. Atomistic molecular dynamics simulation was carried out for both XPA 98-210 systems using AMBER force fields. We observed that XPA 98-210 in presence of damaged DNA exhibited more structural changes compared to XPA 98-210 in its free form. When XPA is in contact with DNA, we found marked stability of the complex due to the formation of characteristic longer antiparallel β-sheets consisting mainly lysine residues.

  11. Status of degraded core issues. Synthesis paper prepared by G. Bandini in collaboration with the NEA task group on degraded core cooling

    International Nuclear Information System (INIS)

    2001-02-01

    The in-vessel evolution of a severe accident in a nuclear reactor is characterised, generally, by core uncover and heat-up, core material oxidation and melting, molten material relocation and debris behaviour in the lower plenum up to vessel failure. The in-vessel core melt progression involves a large number of physical and chemical phenomena that may depend on the severe accident sequence and the reactor type under consideration. Core melt progression has been studied in the last twenty years through many experimental works. Since then, computer codes are being developed and validated to analyse different reactor accident sequences. The experience gained from the TMI-2 accident also constitutes an important source of data. The understanding of core degradation process is necessary to evaluate initial conditions for subsequent phases of the accident (ex-vessel and within the containment), and define accident management strategies and mitigative actions for operating and advanced reactors. This synthesis paper, prepared within the Task Group on Degraded Core Cooling (TG-DCC) of PWG2, contains a brief summary of current views on the status of degraded core issues regarding light water reactors. The in-vessel fission product release and transport issue is not addressed in this paper. The areas with remaining uncertainties and the needs for further experimental investigation and model development have been identified. The early phase of core melt progression is reasonably well understood. Remaining uncertainties may be addressed on the basis of ongoing experimental activities, e.g. on core quenching, and research programs foreseen in the near future. The late phase of core melt progression is less understood. Ongoing research programs are providing additional valuable information on corium molten pool behaviour. Confirmatory research is still required. The pool crust behaviour and material relocation into the lower plenum are the areas where additional research should

  12. Dynamic Network Logistic Regression: A Logistic Choice Analysis of Inter- and Intra-Group Blog Citation Dynamics in the 2004 US Presidential Election

    OpenAIRE

    Almquist, Zack W.; Butts, Carter T.

    2013-01-01

    Methods for analysis of network dynamics have seen great progress in the past decade. This article shows how Dynamic Network Logistic Regression techniques (a special case of the Temporal Exponential Random Graph Models) can be used to implement decision theoretic models for network dynamics in a panel data context. We also provide practical heuristics for model building and assessment. We illustrate the power of these techniques by applying them to a dynamic blog network sampled during the 2...

  13. Conduction properties of KcsA measured using brownian dynamics with flexible carbonyl groups in the selectivity filter.

    Science.gov (United States)

    Chung, Shin-Ho; Corry, Ben

    2007-07-01

    In the narrow segment of an ion conducting pathway, it is likely that a permeating ion influences the positions of the nearby atoms that carry partial or full electronic charges. Here we introduce a method of incorporating the motion of charged atoms lining the pore into Brownian dynamics simulations of ion conduction. The movements of the carbonyl groups in the selectivity filter of the KcsA channel are calculated explicitly, allowing their bond lengths, bond angles, and dihedral angels to change in response to the forces acting upon them. By systematically changing the coefficients of bond stretching and of angle bending, the carbon and oxygen atoms can be made to fluctuate from their fixed positions by varying mean distances. We show that incorporating carbonyl motion in this way does not alter the mechanism of ion conduction and only has a small influence on the computed current. The slope conductance of the channel increases by approximately 25% when the root mean-square fluctuations of the carbonyl groups are increased from 0.01 to 0.61 A. The energy profiles and the number of resident ions in the channel remain unchanged. The method we utilized here can be extended to allow the movement of glutamate or aspartate side chains lining the selectivity filters of other ionic channels.

  14. Dynamics and Structure of Dispute in Open Group of Facebook Social Networking Service in Terms of Teenagers’ Homosexual Relations Education

    Directory of Open Access Journals (Sweden)

    Sergei V. Kharitonov

    2014-05-01

    Full Text Available The article considers the results of discussions in the group of Facebook social networking service, dealing with the problem of teenagers’ homosexual relations education. The goal of the research is to study the dynamics of the dispute in Facebook social networking service on the example of the closed group “Teenagers’ Sexual Orientation”. As a whole, 72 people participated in the discussion, involving both representatives, sharing the views of the LGBT community, concerning homosexual relations and teenagers’ heterosexual parents. As a result of the dispute, conducted within Facebook website 230 comments were left. Resulting from the content analysis of the message texts, the estimation of a number of parameters was made. The estimation showed that the parties of the virtual discussion are in deficit of decisions in terms of virtual disputes conduct. The declared wish to argue out doesn’t lead to the real activity, relevant to evidence-based disputes. Thus, we can consider that the participants of the virtual discussion are in deficit of the decisions in terms of virtual disputes conduct.

  15. Structure and conformational dynamics of the domain 5 RNA hairpin of a bacterial group II intron revealed by solution nuclear magnetic resonance and molecular dynamics simulations.

    Science.gov (United States)

    Pechlaner, Maria; Sigel, Roland K O; van Gunsteren, Wilfred F; Dolenc, Jožica

    2013-10-08

    Nuclear magnetic resonance (NMR) nuclear Overhauser enhancement (NOE) data obtained for a 35-nucleotide RNA segment of a bacterial group II intron indicate a helical hairpin structure in which three parts, a terminal pentaloop, a bulge, and a G-A mismatch, display no Watson-Crick base pairing. The 668 NOE upper distance bounds for atom pairs are insufficient to uniquely determine the conformation of these segments. Therefore, molecular dynamics simulations including time-averaged distance restraints have been used to obtain a conformational ensemble compatible with the observed NMR data. The ensemble shows alternating hydrogen bonding patterns for the mentioned segments. In particular, in the pentaloop and in the bulge, the hydrogen bonding networks correspond to distinct conformational clusters that could not be captured by using conventional single-structure refinement techniques. This implies that, to obtain a realistic picture of the conformational ensemble of such flexible biomolecules, it is necessary to properly account for the conformational variability in the structure refinement of RNA fragments.

  16. A Dynamic Network Approach to the Assessment of Terrorist Groups and the Impact of Alternative Courses of Action

    National Research Council Canada - National Science Library

    Carley, Kathleen M

    2006-01-01

    Dynamic network analysis (DNA) is an emergent field centered on the collection, analysis, understanding and prediction of dynamic relations among various entities such as actors, events and resources and the impact...

  17. Sensitivity Analysis and Optimization for Selected Supply Chain Management Issues in the Company – Using System Dynamics and Vensim

    Directory of Open Access Journals (Sweden)

    Elżbieta Kasperska

    2013-01-01

    Full Text Available The aim of our paper is to present the new results of research work on optimization and simulation for some logistic problems in the company. The System Dynamics (SD method and the Vensim simulation language are applied in order to solve specific managerial problems described by Forrester in the model of supply chain. The historical model of Customer-Producer-Employment System by Forrester (Forrester, 1961 has not been examined with the sensitivity analysis, from the “automatic” testing perspective. Optimization experiments have not been conducted, either. It is surprising, since the model is old and widely known. The opportunities offered by the Vensim language allow us to perform such analysis. The visualization called “confidence bounds“ is used, to show the behaviour of chosen variables over a period of time. The Monte-Carlo method is applied for sampling a set of numbers from within bounded domains (distribution for each searching parameters is specified. The authors of this paper conducted numerous experiments in this scope. This paper presents their results and offers some conclusions formulated at the end.

  18. Study on dynamic multi-objective approach considering coal and water conflict in large scale coal group

    Science.gov (United States)

    Feng, Qing; Lu, Li

    2018-01-01

    In the process of coal mining, destruction and pollution of groundwater in has reached an imminent time, and groundwater is not only related to the ecological environment, but also affect the health of human life. Similarly, coal and water conflict is still one of the world's problems in large scale coal mining regions. Based on this, this paper presents a dynamic multi-objective optimization model to deal with the conflict of the coal and water in the coal group with multiple subordinate collieries and arrive at a comprehensive arrangement to achieve environmentally friendly coal mining strategy. Through calculation, this paper draws the output of each subordinate coal mine. And on this basis, we continue to adjust the environmental protection parameters to compare the coal production at different collieries at different stages under different attitude of the government. At last, the paper conclude that, in either case, it is the first arrangement to give priority to the production of low-drainage, high-yield coal mines.

  19. An Interaction of Economy and Environment in Dynamic Computable General Equilibrium Modelling with a Focus on Climate Change Issues in Korea : A Proto-type Model

    Energy Technology Data Exchange (ETDEWEB)

    Joh, Seung Hun; Dellink, Rob; Nam, Yunmi; Kim, Yong Gun; Song, Yang Hoon [Korea Environment Institute, Seoul (Korea)

    2000-12-01

    In the beginning of the 21st century, climate change is one of hottest issues in arena of both international environment and domestic one. During the COP6 meeting held in The Hague, over 10,000 people got together from the world. This report is a series of policy study on climate change in context of Korea. This study addresses on interactions of economy and environment in a perfect foresight dynamic computable general equilibrium with a focus on greenhouse gas mitigation strategy in Korea. The primary goal of this study is to evaluate greenhouse gas mitigation portfolios of changes in timing and magnitude with a particular focus on developing a methodology to integrate the bottom-up information on technical measures to reduce pollution into a top-down multi-sectoral computable general equilibrium framework. As a non-Annex I country Korea has been under strong pressure to declare GHG reduction commitment. Of particular concern is economic consequences GHG mitigation would accrue to the society. Various economic assessment have been carried out to address on the issue including analyses on cost, ancillary benefit, emission trading, so far. In this vein, this study on GHG mitigation commitment is a timely answer to climate change policy field. Empirical results available next year would be highly demanded in the situation. 62 refs., 13 figs., 9 tabs.

  20. Achieving Successful Employment Outcomes with the Use of Assistive Technology. Report from the Study Group, Institute on Rehabilitation Issues (24th, Washington, DC, May 1998).

    Science.gov (United States)

    Radtke, Jean, Ed.

    Developed as a result of an institute on rehabilitation issues, this document is a guide to assistive technology as it affects successful competitive employment outcomes for people with disabilities. Chapter 1 offers basic information on assistive technology including basic assumptions, service provider approaches, options for technology…

  1. The Child Abuse Matter and the Major Role Played by the Teacher: Issues Raised by a Pilot Focus Group Sample of Primary Teachers

    Science.gov (United States)

    Vitalaki, Elena

    2013-01-01

    A great deal of attention is now being paid to issues raised by child abuse. Recent reports, enquiries and relevant agencies have all recognized the important role played by teachers in aiding the detection and prevention of child abuse, due to their close everyday contact with children. The result of the ideas presented in the present work was…

  2. Light up my day : a between-group test of dynamic lighting effects on office workers' wellbeing in the field

    NARCIS (Netherlands)

    Smolders, K.C.H.J.; Kort, de Y.A.W.; Yener, A.K.; Oztürk, L.D.

    2009-01-01

    Dynamic lighting is designed to have positive effects on wellbeing and performance. However, whether these effects are detectable and stable over time when employed in actual work settings has not been thoroughly investigated. We explore whether beneficial effects of dynamic lighting indeed hold up

  3. The Effect of Group Dynamics-Oriented Instruction on Developing Iranian EFL Learners' Speaking Ability and Willingness to Communicate

    Science.gov (United States)

    Alikhani, Mohsen; Bagheridoust, Esmaeil

    2017-01-01

    The study investigated how group-dynamics instruction techniques of adaptable nature can be to the benefit of EFL (English as a Foreign Language) learners so as to develop and improve their willingness-to-communicate and speaking-ability in the long run. After analyzing the data via ANCOVA and EFA, the researcher selected 108 young Iranian male…

  4. Epidemiology: Past, Present, and Future Impacts on Understanding Disease Dynamics and Improving Plant Disease Management-A Summary of Focus Issue Articles.

    Science.gov (United States)

    Ojiambo, P S; Yuen, J; van den Bosch, F; Madden, L V

    2017-10-01

    Epidemiology has made significant contributions to plant pathology by elucidating the general principles underlying the development of disease epidemics. This has resulted in a greatly improved theoretical and empirical understanding of the dynamics of disease epidemics in time and space, predictions of disease outbreaks or the need for disease control in real-time basis, and tactical and strategic solutions to disease problems. Availability of high-resolution experimental data at multiple temporal and spatial scales has now provided a platform to test and validate theories on the spread of diseases at a wide range of spatial scales ranging from the local to the landscape level. Relatively new approaches in plant disease epidemiology, ranging from network to information theory, coupled with the availability of large-scale datasets and the rapid development of computer technology, are leading to revolutionary thinking about epidemics that can result in considerable improvement of strategic and tactical decision making in the control and management of plant diseases. Methods that were previously restricted to topics such as population biology or evolution are now being employed in epidemiology to enable a better understanding of the forces that drive the development of plant disease epidemics in space and time. This Focus Issue of Phytopathology features research articles that address broad themes in epidemiology including social and political consequences of disease epidemics, decision theory and support, pathogen dispersal and disease spread, disease assessment and pathogen biology and disease resistance. It is important to emphasize that these articles are just a sample of the types of research projects that are relevant to epidemiology. Below, we provide a succinct summary of the articles that are published in this Focus Issue .

  5. Dynamic Network Logistic Regression: A Logistic Choice Analysis of Inter- and Intra-Group Blog Citation Dynamics in the 2004 US Presidential Election

    Science.gov (United States)

    2013-01-01

    Methods for analysis of network dynamics have seen great progress in the past decade. This article shows how Dynamic Network Logistic Regression techniques (a special case of the Temporal Exponential Random Graph Models) can be used to implement decision theoretic models for network dynamics in a panel data context. We also provide practical heuristics for model building and assessment. We illustrate the power of these techniques by applying them to a dynamic blog network sampled during the 2004 US presidential election cycle. This is a particularly interesting case because it marks the debut of Internet-based media such as blogs and social networking web sites as institutionally recognized features of the American political landscape. Using a longitudinal sample of all Democratic National Convention/Republican National Convention–designated blog citation networks, we are able to test the influence of various strategic, institutional, and balance-theoretic mechanisms as well as exogenous factors such as seasonality and political events on the propensity of blogs to cite one another over time. Using a combination of deviance-based model selection criteria and simulation-based model adequacy tests, we identify the combination of processes that best characterizes the choice behavior of the contending blogs. PMID:24143060

  6. Dynamics

    CERN Document Server

    Goodman, Lawrence E

    2001-01-01

    Beginning text presents complete theoretical treatment of mechanical model systems and deals with technological applications. Topics include introduction to calculus of vectors, particle motion, dynamics of particle systems and plane rigid bodies, technical applications in plane motions, theory of mechanical vibrations, and more. Exercises and answers appear in each chapter.

  7. The dynamical groups SO0(3.2) and SO0(4.2) as space-time groups of elementary particles

    International Nuclear Information System (INIS)

    Heidenreich, W.

    1981-01-01

    Elementary particles are described by representations of SO 0 (4.2) and SO 0 (3.2). An S-matrix invariant under the corresponding group constrains the possible scattering channels. The simptest used representations have each one gauge freedom, the physical significance of which is discussed. 'Higher' representations can be constructed from the simplest by means of the tensor product; the same is true for the corresponding particles. The simplest objects of the SO 0 (3.2) theory, the SO 0 (3.2) theory, the Dirac singletons correspond to the states of a 2-dimensional harmonic oscillator. The basic states of this are interpreted as urs in the sense of von Weizsaecker. (orig./HSI) [de

  8. Intelligence in the power grid and services to the consumers. Issue paper - working group 4; Denmark. Smart Grid Network; Intelligens i el-nettet og serviceydelser til forbrugerne. Issue paper, arbejdsgruppe 4

    Energy Technology Data Exchange (ETDEWEB)

    Jonsen, B.O. (Solar Danmark A/S, Vejen (Denmark)); Hauge, B. (IT-Branchen, Copenhagen (Denmark)); Strunge, C. (Energinet.dk, Fredericia (Denmark)) (and others)

    2011-07-01

    The Smart Grid Network was established in 2010 by the Danish climate and energy minister tasked with developing recommendations for future actions and initiatives that make it possible to handle up to 50% electricity from wind energy in the power system in 2020. The task of working group 4 was to investigate what it takes to involve consumers in smart grid and how to create good conditions for new services related to smart grid. Against this background, the working group agreed the following recommendations: 1) Enhance consumer engagement. A prerequisite for electricity customers becoming involved in smart grid is that they have awareness and knowledge about the smart grid and their own possibilities for action in relation thereto. Therefore it is important that concepts such as smart grid and flexible electricity consumption gradually become popular among electric customers; 2) Minimize the risk. In order to promote electric customers' and other stakeholders' participation in the smart grid, the risk of this participation must be minimized. It is therefore recommended to enhance the skills of the professionals and to establish a common framework for security; 3) Make it easier to create new services. Part of the potential of smart grid can be realized through new services such as delivery of flexible electricity consumption for electric cars and heat pumps and the resale of local power generation at the customer. To facilitate the conditions for these services, the working group recommends that better access to relevant data is created, that the interoperability of smart grid solutions is strengthened, that requirements for buildings are made, that it is made easier to be an aggregator, and that test and inspiration laboratories for small and medium enterprises in the smart grid area are established. (LN)

  9. Unemployment Dynamics and Age

    NARCIS (Netherlands)

    Berg, van den G.J.; Gijsbert, A.; Lomwel, van C.; Ours, van Jan C.

    1998-01-01

    Youth unemployment is an issue of primary concern in WesternEuropean countries. In this paper we analyze dynamics in unemployment foryouths, adults (prime-aged individuals), and elderly. We use quarterly Frenchunemployment data, stratified by gender, age group, and duration, over theperiod

  10. Upstream oil and gas industry options paper : report of the upstream oil and gas working group of the Industry Issues Table to the National Climate Change Secretariat

    International Nuclear Information System (INIS)

    1999-09-01

    The Canadian Association of Petroleum Producers (CAPP) has coordinated the efforts of the upstream oil and natural gas industry to draft a foundation paper to provide data on industry greenhouse gas (GHG) emissions and actions. This paper is a technical piece targeted at government officials and stakeholders involved in the National Climate Change Secretariat process. The paper also outlines the context for considering policies aimed at reducing oil and gas industry emissions on climate change. The 6 key messages that CAPP wanted to emphasize in this paper were: (1) Canada's situation is very different from that of the U.S. and most other industrial countries, (2) GHG emissions are primarily an end-use consumption issue, (3) the climate change issue and the Kyoto Protocol present a major uncertainty that could undermine Canadian oil and natural gas development opportunities, (4) Canada should not be penalised by its growth of oil and natural gas resources, (5) the ability to reduce emissions by changing production technology is limited because large reductions in Canadian upstream emissions would only mean a shift of production to other countries which would not help to reduce global emissions, and (6) Canada should focus on promoting cost-effective action, research and development and international flexibility, and ensure that recognition is given to those companies that reduce emissions. tabs., figs

  11. Continual approach to the dynamics problems of tanks containing rod bundles or particle groups and fluid at vibrational actions

    International Nuclear Information System (INIS)

    Fedotovskii, V.S.

    1988-02-01

    The vibration of tanks with liquid and non deformed cylindrical or spherical inclusions are considered. It is shown that for calculating dynamic characteristics of such systems it is advisable to use continual approach i.e. consider-heterogeneous media formed by liquid and weighted inclusions in it as homogeneous media with effective or vibroreological properties. On the base of the problem on vibrations of the tank, containing liquid and localized inclusions, rod assemblies vibrations are considered and relationships for the added mass and resistance coefficient determining dynamic characteristics of such systems are obtained. Considered are also liquid tank vibrations containing spherical inclusions. The results obtained are used for calculating dynamic characteristics of two-phase flow pipelines at bubble and annular flow mode. The theoretical relationships are compared with available experimental data [fr

  12. Liability Issues

    International Nuclear Information System (INIS)

    O’Donoghue, K.

    2016-01-01

    Nuclear liability conventions try to provide a set of rules to govern third party liability. Not all States are parties to one of the existing liability conventions. There are a number of reasons why individual States may choose not to join one of the existing conventions. These include limits of compensation, jurisdiction issues, complexity, cost and definition of damage among others. This paper looks at the existing conventions and identifies some of the main issues in the existing conventions which prevent some States from signing them. The paper attempts to tease out some of the perceived gaps in the existing conventions and give a brief description of the reasons why non-Contracting Parties have difficulty with the provisions of the conventions. The paper recognizes that there has been work done in this area previously by the International Expert Group on Nuclear Liability (INLEX) and others to try to develop the existing frameworks to enhance global adherence by nuclear and non-nuclear States to an effective nuclear liability regime. (author)

  13. Critical issues with the in vivo comet assay: A report of the comet assay working group in the 6th International Workshop on Genotoxicity Testing (IWGT).

    Science.gov (United States)

    Speit, Günter; Kojima, Hajime; Burlinson, Brian; Collins, Andrew R; Kasper, Peter; Plappert-Helbig, Ulla; Uno, Yoshifumi; Vasquez, Marie; Beevers, Carol; De Boeck, Marlies; Escobar, Patricia A; Kitamoto, Sachiko; Pant, Kamala; Pfuhler, Stefan; Tanaka, Jin; Levy, Dan D

    2015-05-01

    As a part of the 6th IWGT, an expert working group on the comet assay evaluated critical topics related to the use of the in vivo comet assay in regulatory genotoxicity testing. The areas covered were: identification of the domain of applicability and regulatory acceptance, identification of critical parameters of the protocol and attempts to standardize the assay, experience with combination and integration with other in vivo studies, demonstration of laboratory proficiency, sensitivity and power of the protocol used, use of different tissues, freezing of samples, and choice of appropriate measures of cytotoxicity. The standard protocol detects various types of DNA lesions but it does not detect all types of DNA damage. Modifications of the standard protocol may be used to detect additional types of specific DNA damage (e.g., cross-links, bulky adducts, oxidized bases). In addition, the working group identified critical parameters that should be carefully controlled and described in detail in every published study protocol. In vivo comet assay results are more reliable if they were obtained in laboratories that have demonstrated proficiency. This includes demonstration of adequate response to vehicle controls and an adequate response to a positive control for each tissue being examined. There was a general agreement that freezing of samples is an option but more data are needed in order to establish generally accepted protocols. With regard to tissue toxicity, the working group concluded that cytotoxicity could be a confounder of comet results. It is recommended to look at multiple parameters such as histopathological observations, organ-specific clinical chemistry as well as indicators of tissue inflammation to decide whether compound-specific toxicity might influence the result. The expert working group concluded that the alkaline in vivo comet assay is a mature test for the evaluation of genotoxicity and can be recommended to regulatory agencies for use

  14. Report of the AAPM Task Group No. 105: Issues associated with clinical implementation of Monte Carlo-based photon and electron external beam treatment planning

    International Nuclear Information System (INIS)

    Chetty, Indrin J.; Curran, Bruce; Cygler, Joanna E.; DeMarco, John J.; Ezzell, Gary; Faddegon, Bruce A.; Kawrakow, Iwan; Keall, Paul J.; Liu, Helen; Ma, C.-M. Charlie; Rogers, D. W. O.; Seuntjens, Jan; Sheikh-Bagheri, Daryoush; Siebers, Jeffrey V.

    2007-01-01

    The Monte Carlo (MC) method has been shown through many research studies to calculate accurate dose distributions for clinical radiotherapy, particularly in heterogeneous patient tissues where the effects of electron transport cannot be accurately handled with conventional, deterministic dose algorithms. Despite its proven accuracy and the potential for improved dose distributions to influence treatment outcomes, the long calculation times previously associated with MC simulation rendered this method impractical for routine clinical treatment planning. However, the development of faster codes optimized for radiotherapy calculations and improvements in computer processor technology have substantially reduced calculation times to, in some instances, within minutes on a single processor. These advances have motivated several major treatment planning system vendors to embark upon the path of MC techniques. Several commercial vendors have already released or are currently in the process of releasing MC algorithms for photon and/or electron beam treatment planning. Consequently, the accessibility and use of MC treatment planning algorithms may well become widespread in the radiotherapy community. With MC simulation, dose is computed stochastically using first principles; this method is therefore quite different from conventional dose algorithms. Issues such as statistical uncertainties, the use of variance reduction techniques, the ability to account for geometric details in the accelerator treatment head simulation, and other features, are all unique components of a MC treatment planning algorithm. Successful implementation by the clinical physicist of such a system will require an understanding of the basic principles of MC techniques. The purpose of this report, while providing education and review on the use of MC simulation in radiotherapy planning, is to set out, for both users and developers, the salient issues associated with clinical implementation and

  15. Application of system dynamics and participatory spatial group model building in animal health: A case study of East Coast Fever interventions in Lundazi and Monze districts of Zambia.

    Science.gov (United States)

    Mumba, Chisoni; Skjerve, Eystein; Rich, Magda; Rich, Karl M

    2017-01-01

    East Coast Fever (ECF) is the most economically important production disease among traditional beef cattle farmers in Zambia. Despite the disease control efforts by the government, donors, and farmers, ECF cases are increasing. Why does ECF oscillate over time? Can alternative approaches such as systems thinking contribute solutions to the complex ECF problem, avoid unintended consequences, and achieve sustainable results? To answer these research questions and inform the design and implementation of ECF interventions, we qualitatively investigated the influence of dynamic socio-economic, cultural, and ecological factors. We used system dynamics modelling to specify these dynamics qualitatively, and an innovative participatory framework called spatial group model building (SGMB). SGMB uses participatory geographical information system (GIS) concepts and techniques to capture the role of spatial phenomenon in the context of complex systems, allowing stakeholders to identify spatial phenomenon directly on physical maps and integrate such information in model development. Our SGMB process convened focus groups of beef value chain stakeholders in two distinct production systems. The focus groups helped to jointly construct a series of interrelated system dynamics models that described ECF in a broader systems context. Thus, a complementary objective of this study was to demonstrate the applicability of system dynamics modelling and SGMB in animal health. The SGMB process revealed policy leverage points in the beef cattle value chain that could be targeted to improve ECF control. For example, policies that develop sustainable and stable cattle markets and improve household income availability may have positive feedback effects on investment in animal health. The results obtained from a SGMB process also demonstrated that a "one-size-fits-all" approach may not be equally effective in policing ECF in different agro-ecological zones due to the complex interactions of socio

  16. Application of system dynamics and participatory spatial group model building in animal health: A case study of East Coast Fever interventions in Lundazi and Monze districts of Zambia.

    Directory of Open Access Journals (Sweden)

    Chisoni Mumba

    Full Text Available East Coast Fever (ECF is the most economically important production disease among traditional beef cattle farmers in Zambia. Despite the disease control efforts by the government, donors, and farmers, ECF cases are increasing. Why does ECF oscillate over time? Can alternative approaches such as systems thinking contribute solutions to the complex ECF problem, avoid unintended consequences, and achieve sustainable results? To answer these research questions and inform the design and implementation of ECF interventions, we qualitatively investigated the influence of dynamic socio-economic, cultural, and ecological factors. We used system dynamics modelling to specify these dynamics qualitatively, and an innovative participatory framework called spatial group model building (SGMB. SGMB uses participatory geographical information system (GIS concepts and techniques to capture the role of spatial phenomenon in the context of complex systems, allowing stakeholders to identify spatial phenomenon directly on physical maps and integrate such information in model development. Our SGMB process convened focus groups of beef value chain stakeholders in two distinct production systems. The focus groups helped to jointly construct a series of interrelated system dynamics models that described ECF in a broader systems context. Thus, a complementary objective of this study was to demonstrate the applicability of system dynamics modelling and SGMB in animal health. The SGMB process revealed policy leverage points in the beef cattle value chain that could be targeted to improve ECF control. For example, policies that develop sustainable and stable cattle markets and improve household income availability may have positive feedback effects on investment in animal health. The results obtained from a SGMB process also demonstrated that a "one-size-fits-all" approach may not be equally effective in policing ECF in different agro-ecological zones due to the complex

  17. Central sensitivity syndromes: a new paradigm and group nosology for fibromyalgia and overlapping conditions, and the related issue of disease versus illness.

    Science.gov (United States)

    Yunus, Muhammad B

    2008-06-01

    To discuss the current terminologies used for fibromyalgia syndrome (FMS) and related overlapping conditions, to examine if central sensitivity syndromes (CSS) is the appropriate nosology for these disorders, and to explore the issue of disease versus illness. A literature search was performed through PubMed, Web of Science, and ScienceDirect using a number of keywords, eg, functional somatic syndromes, somatoform disorders, medically unexplained symptoms, organic and nonorganic, and diseases and illness. Relevant articles were then reviewed and representative ones cited. Terminologies currently used for CSS conditions predominantly represent a psychosocial construct and are inappropriate. On the other hand, CSS seems to be the logical nosology based on a biopsychosocial model. Such terms as "medically unexplained symptoms," "somatization," "somatization disorder," and "functional somatic syndromes" in the context of CSS should be abandoned. Given current scientific knowledge, the concept of disease-illness dualism has no rational basis and impedes proper patient-physician communication, resulting in poor patient care. The concept of CSS is likely to promote research, education, and proper patient management. CSS seems to be a useful paradigm and an appropriate terminology for FMS and related conditions. The disease-illness, as well as organic/non-organic dichotomy, should be rejected.

  18. A close examination of the structure and dynamics of HC(NH2)2PbI3by MD simulations and group theory

    KAUST Repository

    Carignano, M. A.

    2016-06-22

    The formamidinium lead iodide hybrid perovskite is studied using first principles molecular dynamics simulations and further analyzed using group theory. The simulations are performed on large supercells containing 768 atoms under isothermal and fully anisotropic isobaric conditions. Two trajectories, one at 300 K and another at 450 K, were extended for over 50 ps in order to perform a detailed assessment of the rotational dynamics of organic cations. The characteristic rotations of the cation are analyzed by defining two rotation axes. It is found that the formamidinium molecules rotate preferentially around the direction parallel to the line connecting the two nitrogen atoms. The rotational dynamics shows some characteristics already observed in methylammonium lead iodide, like the heterogeneous dynamics at room temperature that disappears at 450 K. The orientational probability of the molecules is explored in terms of an expansion in cubic harmonics up to the 12th order. It reveals a strong directionality at room temperature that relaxes when increasing the temperature. These findings are further rationalized using Landau and group theories suggesting a mixed displacive/order-disorder structural instability at lower temperatures.

  19. Effect of glass-forming biopreservatives on head group rotational dynamics in freeze-dried phospholipid bilayers: A 31P NMR study

    Science.gov (United States)

    Jain, P.; Sen, S.; Risbud, S. H.

    2009-07-01

    P31 NMR spectroscopy has been used to elucidate the role of glass-forming sugars in the preservation of dipalmitoylphosphatidylcholine (DPPC) lipid bilayers. P31 wideline NMR spectra of freeze-dried pure DPPC, DPPC/trehalose, DPPC/glucose, and DPPC/hydroxyethyl starch (HES) mixtures collected in the temperature range of 25-80 °C have been simulated to obtain quantitative information about rotational dynamics and orientation of the lipid head groups in these media. In the case of pure DPPC, DPPC/glucose, and DPPC/HES, the gel-to-liquid crystalline phase transition of DPPC bilayer is characterized by a sudden increase in the rate of rotational diffusion of the PO4 head groups near 40 °C. The corresponding rotational jump frequency increases from a few kilohertz in the gel phase to at least several megahertz in the liquid crystalline phase. On the other hand, in the case of DPPC/trehalose mixture the temperature of this onset of rapid head group dynamics is increased by ˜10 °C. Trehalose reduces the lipid head group motions most effectively in the temperature range of T ≤50 °C relevant for biopreservation. Additionally, and possibly more importantly, trehalose is found to strongly restrict any change in the orientation of the diffusion axis of the PO4 head groups during the phase transformation. This unique ability of trehalose to maintain the dynamical and orientational rigidity of lipid head groups is likely to be responsible for its superior ability in biopreservation.

  20. National platform electromobility. Working group 4 - Key issue paper standardization and certification; Nationale Plattform Elektromobilitaet. AG 4 - Eckpunktepapier Normung, Standardisierung und Zertifizierung

    Energy Technology Data Exchange (ETDEWEB)

    Hoelk, Stephanie [Audi AG, Ingolstadt (Germany). I/EM-1

    2010-07-01

    On behalf of the working group 4 ''Standardization and certification ''of the national platform electromobility arranged by the Federal Government, the ''German standardization roadmap electromobility'' was compiled. This gives a survey of the existing structures and definitions of the standardization and designates substantial demands and recommendations for action in order to contribute to the break-through of the electromobility in Europe and in the world. The position paper summarizes the central asking of the standardization roadmap. It identifies necessary basic conditions, appoints concrete recommendations for action and shows the further demand for action for the standardization.

  1. National platform electromobility. Working group 4 - Key issue paper standardization and certification; Nationale Plattform Elektromobilitaet. AG 4 - Eckpunktepapier Normung, Standardisierung und Zertifizierung

    Energy Technology Data Exchange (ETDEWEB)

    Hoelk, Stephanie (comp.) [Audi AG, Ingolstadt (Germany). I/EM-1

    2010-07-01

    On behalf of the working group 4 ''Standardization and certification ''of the national platform electromobility arranged by the Federal Government, the ''German standardization roadmap electromobility'' was compiled. This gives a survey of the existing structures and definitions of the standardization and designates substantial demands and recommendations for action in order to contribute to the break-through of the electromobility in Europe and in the world. The position paper summarizes the central asking of the standardization roadmap. It identifies necessary basic conditions, appoints concrete recommendations for action and shows the further demand for action for the standardization.

  2. Social structure in a family group of Guanaco (Lama guanicoe, Ungulate): is female hierarchy based on 'prior attributes' or 'social dynamics'?

    Science.gov (United States)

    Correa, Loreto A; Zapata, Beatriz; Samaniego, Horacio; Soto-Gamboa, Mauricio

    2013-09-01

    Social life involves costs and benefits mostly associated with how individuals interact with each other. The formation of hierarchies inside social groups has evolved as a common strategy to avoid high costs stemming from social interactions. Hierarchical relationships seem to be associated with different features such as body size, body condition and/or age, which determine dominance ability ('prior attributes' hypothesis). In contrast, the 'social dynamic' hypothesis suggests that an initial social context is a determinant in the formation of the hierarchy, more so than specific individual attributes. Hierarchical rank places individuals in higher positions, which presumably increases resource accessibility to their benefit, including opportunities for reproduction. We evaluate the maintenance of hierarchy in a family group of guanacos (Lama guanicoe) and evaluate the possible mechanisms involved in the stability of these interactions and their consequences. We estimate the linearity of social hierarchy and their dynamics. We find evidence of the formation of a highly linear hierarchy among females with males positioned at the bottom of the hierarchy. This hierarchy is not affected by physical characteristics or age, suggesting that it is established only through intra-group interactions. Rank is not related with calves' weight gain either; however, subordinated females, with lower rank, exhibit higher rates of allosuckling. We found no evidence of hierarchical structure in calves suggesting that hierarchical relationship in guanacos could be established during the formation of the family group. Hence, our results suggest that hierarchical dynamics could be related more to social dynamics than to prior attributes. We finally discuss the importance of hierarchies established by dominance and their role in minimizing social costs of interactions. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Dynamic contrast-enhanced computed tomography as a potential biomarker in patients with metastatic renal cell carcinoma: preliminary results from the Danish Renal Cancer Group Study-1

    DEFF Research Database (Denmark)

    Mains, Jill Rachel; Donskov, Frede; Pedersen, Erik Morre

    2014-01-01

    OBJECTIVES: The aim of this study was to explore the impact of dynamic contrast-enhanced (DCE) computer tomography (CT) as a biomarker in metastatic renal cell carcinoma (mRCC). MATERIALS AND METHODS: Twelve patients with favorable or intermediate Memorial Sloan Kettering Cancer Center risk group...... blinded to treatment group. The DCE-CT scans were performed at baseline, at weeks 5 and 10, and thereafter every third month. Blood flow (BF; mL/min/100 mL), peak enhancement (Hounsfield units), time to peak (seconds), and blood volume (BV; mL/100 g) were calculated. Parameters for DCE-CT were correlated...

  4. Immunity-based optimal estimation approach for a new real time group elevator dynamic control application for energy and time saving.

    Science.gov (United States)

    Baygin, Mehmet; Karakose, Mehmet

    2013-01-01

    Nowadays, the increasing use of group elevator control systems owing to increasing building heights makes the development of high-performance algorithms necessary in terms of time and energy saving. Although there are many studies in the literature about this topic, they are still not effective enough because they are not able to evaluate all features of system. In this paper, a new approach of immune system-based optimal estimate is studied for dynamic control of group elevator systems. The method is mainly based on estimation of optimal way by optimizing all calls with genetic, immune system and DNA computing algorithms, and it is evaluated with a fuzzy system. The system has a dynamic feature in terms of the situation of calls and the option of the most appropriate algorithm, and it also adaptively works in terms of parameters such as the number of floors and cabins. This new approach which provides both time and energy saving was carried out in real time. The experimental results comparatively demonstrate the effects of method. With dynamic and adaptive control approach in this study carried out, a significant progress on group elevator control systems has been achieved in terms of time and energy efficiency according to traditional methods.

  5. Immunity-Based Optimal Estimation Approach for a New Real Time Group Elevator Dynamic Control Application for Energy and Time Saving

    Directory of Open Access Journals (Sweden)

    Mehmet Baygin

    2013-01-01

    Full Text Available Nowadays, the increasing use of group elevator control systems owing to increasing building heights makes the development of high-performance algorithms necessary in terms of time and energy saving. Although there are many studies in the literature about this topic, they are still not effective enough because they are not able to evaluate all features of system. In this paper, a new approach of immune system-based optimal estimate is studied for dynamic control of group elevator systems. The method is mainly based on estimation of optimal way by optimizing all calls with genetic, immune system and DNA computing algorithms, and it is evaluated with a fuzzy system. The system has a dynamic feature in terms of the situation of calls and the option of the most appropriate algorithm, and it also adaptively works in terms of parameters such as the number of floors and cabins. This new approach which provides both time and energy saving was carried out in real time. The experimental results comparatively demonstrate the effects of method. With dynamic and adaptive control approach in this study carried out, a significant progress on group elevator control systems has been achieved in terms of time and energy efficiency according to traditional methods.

  6. The effect of device number and role assignment on social group dynamics in location-based learning

    DEFF Research Database (Denmark)

    Christensen, Bianca Clavio; Giakalis, Alexandros Panagiotis; Jørgensen, Nicolai Melgaard

    2016-01-01

    The behavior of being disengaged in group work is commonly defined as social loafing. This disengagement can be reduced by various factors, such as group members having individual accountability in the form of unique tasks. This paper examines social loafing in a collaborative mobile game in groups...... of three users. The game promotes individual accountability in role differentiation on a shared tablet, and these roles are compared to a condition without roles. Another condition tested if a shared tablet would reduce social loafing, compared to individual tablets for each group member. The game...... was tested on 41 students from 7th to 8th grade. Using a tablet each showed significantly more instances of social loafing compared to sharing one. The results show no significant difference for role assignment....

  7. 'Hooligans' abroad? Inter-group dynamics, social identity and participation in collective 'disorder' at the 1998 World Cup Finals.

    Science.gov (United States)

    Stott, C; Hutchison, P; Drury, J

    2001-09-01

    During the 1998 Football World Cup Finals in France, English supporters were, once again, involved in major incidents of collective 'disorder'. Explanations for these incidents concentrated on the conflictual norms held by 'hooligans'. In contrast, Scottish supporters attending the tournament displayed norms of non-violence, explained by the popular press in terms of the absence of 'hooligans'. This study challenges this tendency to explain the presence or absence of 'disorder' in the context of football solely in terms of the presence or absence of 'hooligan' fans. Using data obtained from an ethnographic study of both Scottish and English supporters attending the tournament (N = 121), we examine the processes through which ordinarily 'peaceful' supporters would or would not become involved in collective conflict. In line with the Elaborated Social Identity Model (ESIM) of crowd behaviour, the analysis highlights the role of the intergroup context. Where out-group activity was understood as illegitimate in in-group terms, in-group members redefined their identity such that violent action toward out-group members came to be understood as legitimate. By contrast, where there was no out-group hostility, in-group members defined themselves through an explicit contrast with the 'hooligan' supporters of rival teams. This analysis represents an advance on previous studies of crowd behaviour by demonstrating how the ESIM can account for not only the presence, but also the absence, of collective 'disorder'.

  8. Effects of functional group substitution on electron spectra and solvation dynamics in a family of ionic liquids

    International Nuclear Information System (INIS)

    Wishart, James F.; Lall-Ramnarine, Sharon I.; Raju, Ravinder; Scumpia, Alexander; Bellevue, Sherly; Ragbir, Revans; Engel, Robert

    2005-01-01

    Ionic liquids containing ether-, alcohol- and alkyl-functionalized quaternary ammonium dications were studied by pulse radiolysis. Spectra on nanosecond timescales revealed that solvation of the excess electron is particularly slow in the case of the alcohol-derivatized ionic liquids. The blue shift of the electron spectrum to the customary 650 nm peak takes 25-40 ns at 21 deg. C. Comparison with the relaxation dynamics observed in viscous 1,2,6-trihydroxyhexane reveals the hindering effect of the ionic liquid lattice on hydroxypropyl side chain reorientation

  9. Nonequilibrium Dynamics of Anisotropic Large Spins in the Kondo Regime: Time-Dependent Numerical Renormalization Group Analysis

    Science.gov (United States)

    Roosen, David; Wegewijs, Maarten R.; Hofstetter, Walter

    2008-02-01

    We investigate the time-dependent Kondo effect in a single-molecule magnet (SMM) strongly coupled to metallic electrodes. Describing the SMM by a Kondo model with large spin S>1/2, we analyze the underscreening of the local moment and the effect of anisotropy terms on the relaxation dynamics of the magnetization. Underscreening by single-channel Kondo processes leads to a logarithmically slow relaxation, while finite uniaxial anisotropy causes a saturation of the SMM’s magnetization. Additional transverse anisotropy terms induce quantum spin tunneling and a pseudospin-1/2 Kondo effect sensitive to the spin parity.

  10. Group Dynamics in Long -term blind endeavors on Earth as an analog for Remote Space Missions (Lewis & Clark Expedition, 1803 - 1806, Dynamic Analysis)

    Science.gov (United States)

    Allner, M.; Rygalov, V.; Reilly, J.

    In 1803 President Thomas Jefferson set fourth a military expedition led by Captains newline M Lewis and W Clark L C Expedition on an exploration to learn more about the large territory of land the U S had just purchased from France Cavan 1991 Their mission was to find a direct water route to the Pacific Ocean for the purpose of commerce and further industrial development Edwards 1999 Looking back at the events of this exploration there are many similarities to the experiences future human space explorers will face as we look to colonize the Moon and travel to Mars and beyond NASA Vision for Space Exploration 2004 - The L C Expedition lasted almost three years and involved a crew of 43 men traveling up the Missouri River to explore the unknown lands and a possible water route to the Pacific Ocean newline - The expedition took place far away from customary comfortable environments known to European settlers in early 18th century newline - The expedition involved a remotely confined high-perceived risk environment with high levels of uncertainty providing stresses and every day challenges for the crew newline - Supplies brought on the mission were limited mainly a mass weight issue rather than cost therefore the discovery and use of environmental resources In-Situ Resource Utilization approach including info-resources to mitigate uncertainty was necessary for crew survival The environments astronauts will encounter in space and on the Moon and Mars due to high risk and uncertainty will be in many aspects similar

  11. Health-seeking behavior and transmission dynamics in the control of influenza infection among different age groups.

    Science.gov (United States)

    You, Shu-Han; Chen, Szu-Chieh; Liao, Chung-Min

    2018-01-01

    It has been found that health-seeking behavior has a certain impact on influenza infection. However, behaviors with/without risk perception on the control of influenza transmission among age groups have not been well quantified. The purpose of this study was to assess to what extent, under scenarios of with/without control and preventive/protective behaviors, the age-specific network-driven risk perception influences influenza infection. A behavior-influenza model was used to estimate the spread rate of age-specific risk perception in response to an influenza outbreak. A network-based information model was used to assess the effect of network-driven risk perception information transmission on influenza infection. A probabilistic risk model was used to assess the infection risk effect of risk perception with a health behavior change. The age-specific overlapping percentage was estimated to be 40%-43%, 55%-60%, and 19%-35% for child, teenage and adult, and elderly age groups, respectively. Individuals perceive the preventive behavior to improve risk perception information transmission among teenage and adult and elderly age groups, but not in the child age group. The population with perceived health behaviors could not effectively decrease the percentage of infection risk in the child age group, whereas for the elderly age group, the percentage of decrease in infection risk was more significant, with a 97.5th percentile estimate of 97%. The present integrated behavior-infection model can help health authorities in communicating health messages for an intertwined belief network in which health-seeking behavior plays a key role in controlling influenza infection.

  12. Collective motion in animal groups from a neurobiological perspective: the adaptive benefits of dynamic sensory loads and selective attention.

    Science.gov (United States)

    Lemasson, B H; Anderson, J J; Goodwin, R A

    2009-12-21

    We explore mechanisms associated with collective animal motion by drawing on the neurobiological bases of sensory information processing and decision-making. The model uses simplified retinal processes to translate neighbor movement patterns into information through spatial signal integration and threshold responses. The structure provides a mechanism by which individuals can vary their sets of influential neighbors, a measure of an individual's sensory load. Sensory loads are correlated with group order and density, and we discuss their adaptive values in an ecological context. The model also provides a mechanism by which group members can identify, and rapidly respond to, novel visual stimuli.

  13. Task dynamics in self-organising task groups : expertise, motivational, and performance differences of specialists and generalists

    NARCIS (Netherlands)

    Zoethout, Kees; Jager, Wander; Molleman, Eric

    Multi-agent simulation is applied to explore how different types of task variety cause workgroups to change their task allocation accordingly. We studied two groups, generalists and specialists. We hypothesised that the performance of the specialists would decrease when task variety increases. The

  14. Dynamics and stratification of functional groups of micro- and mesoarthropods in the organic layer of a Scots pine forest.

    NARCIS (Netherlands)

    Berg, M.P.; Kniese, J.P.; Bedaux, J.J.M.; Verhoef, H.A.

    1998-01-01

    This paper addresses the abundance, biomass and microstratification of functional groups of micro- and mesoarthropods inhabiting the organic layers of a Scots pine forest (Pinus sylvestris L.). An experiment using stratified litterbags, containing organic material of four degradation stages, i.e.,

  15. Psychotherapy with schizophrenics in team groups: a systems model.

    Science.gov (United States)

    Beeber, A R

    1991-01-01

    This paper focuses on the treatment of patients with schizophrenic disorders employing the Team Group model. The advantages and disadvantages of the Team Group are presented. Systems theory and principles of group development are applied as a basis for understanding the dynamics of the group in the context at the acute psychiatric unit. Particular problems encountered in treating patients with schizophrenic disorders in this setting are presented. These include: (1) issues of therapist style and technique, (2) basic psychopathology of the schizophrenic disorders, and (3) phase-specific problems associated with the dynamics of the group. Recommendations for therapist interventions are made that may better integrate these patients into the Team Group.

  16. Role of the H-containing groups on the structural dynamics of Ti3C2Tx MXene

    Science.gov (United States)

    Wen, Jing; Zhang, Xitian; Gao, Hong

    2018-05-01

    It is a confused problem in the literature that the c-axis value of Ti3C2 MXene changes with the synthesis procedure, but the part of the surface structures that plays the role of pillar to support the Ti3C2 layers and their variation rules remain controversial. In this work, we develop the structure models and formation mechanisms of Ti3C2Tx based on the density functional theory calculations and experimental results. While the c-axis values of the samples vary from about 1.9 to 2.9 nm, the corresponding pillars are determined by different distributions and proportions of the H-containing groups. The proportions of the H-containing groups that determine the c-axis value are formulated as the functions of the interlayer space, which can be used to quantitatively clarify the changes of the surface functional groups after the samples experiencing different treatments. The results can facilitate the in situ detections of the surface structures of MXenes during different treatments or electrochemical processes.

  17. Veno-occlusive disease nurse management: development of a dynamic monitoring tool by the GITMO nursing group.

    Science.gov (United States)

    Botti, Stefano; Orlando, Laura; Gargiulo, Gianpaolo; Cecco, Valentina De; Banfi, Marina; Duranti, Lorenzo; Samarani, Emanuela; Netti, Maria Giovanna; Deiana, Marco; Galuppini, Vera; Pignatelli, Adriana Concetta; Ceresoli, Rosanna; Vedovetto, Alessio; Rostagno, Elena; Bambaci, Marilena; Dellaversana, Cristina; Luminari, Stefano; Bonifazi, Francesca

    2016-01-01

    Veno-occlusive disease (VOD) is a complication arising from the toxicity of conditioning regimens that have a significant impact on the survival of patients who undergo stem cell transplantation. There are several known risk factors for developing VOD and their assessment before the start of conditioning regimens could improve the quality of care. Equally important are early identification of signs and symptoms ascribable to VOD, rapid diagnosis, and timely adjustment of support therapy and treatment. Nurses have a fundamental role at the stages of assessment and monitoring for signs and symptoms; therefore, they should have documented skills and training. The literature defines nurses' areas of competence in managing VOD, but in the actual clinical practice, this is not so clear. Moreover, there is an intrinsic difficulty in managing VOD due to its rapid and often dramatic evolution, together with a lack of care tools to guide nurses. Through a complex evidence-based process, the Gruppo Italiano per il Trapianto di Midollo Osseo (GITMO), cellule staminali emopoietiche e terapia cellulare nursing board has developed an operational flowchart and a dynamic monitoring tool applicable to haematopoietic stem cell transplantation patients, whether they develop this complication or not.

  18. Pregnancy and Reproductive Issues

    Science.gov (United States)

    ... Health Pregnancy Share this page Facebook Twitter Email Pregnancy and Reproductive Issues Tahirah Diagnosed in 2003 Pregnancy ... in control groups without the disease. Effects of pregnancy on MS Before 1950, most women with MS ...

  19. Changes in the structure and function of northern Alaskan ecosystems when considering variable leaf-out times across groupings of species in a dynamic vegetation model

    Science.gov (United States)

    Euskirchen, E.S.; Carman, T.B.; McGuire, Anthony David

    2013-01-01

    The phenology of arctic ecosystems is driven primarily by abiotic forces, with temperature acting as the main determinant of growing season onset and leaf budburst in the spring. However, while the plant species in arctic ecosystems require differing amounts of accumulated heat for leaf-out, dynamic vegetation models simulated over regional to global scales typically assume some average leaf-out for all of the species within an ecosystem. Here, we make use of air temperature records and observations of spring leaf phenology collected across dominant groupings of species (dwarf birch shrubs, willow shrubs, other deciduous shrubs, grasses, sedges, and forbs) in arctic and boreal ecosystems in Alaska. We then parameterize a dynamic vegetation model based on these data for four types of tundra ecosystems (heath tundra, shrub tundra, wet sedge tundra, and tussock tundra), as well as ecotonal boreal white spruce forest, and perform model simulations for the years 1970 -2100. Over the course of the model simulations, we found changes in ecosystem composition under this new phenology algorithm compared to simulations with the previous phenology algorithm. These changes were the result of the differential timing of leaf-out, as well as the ability for the groupings of species to compete for nitrogen and light availability. Regionally, there were differences in the trends of the carbon pools and fluxes between the new phenology algorithm and the previous phenology algorithm, although these differences depended on the future climate scenario. These findings indicate the importance of leaf phenology data collection by species and across the various ecosystem types within the highly heterogeneous Arctic landscape, and that dynamic vegetation models should consider variation in leaf-out by groupings of species within these ecosystems to make more accurate projections of future plant distributions and carbon cycling in Arctic regions.

  20. Dynamics of B group vitamins - the exametabolits of algae in lake Drukshiai - the cooler of Ignalina NPP in 1994

    International Nuclear Information System (INIS)

    Shlapkauskaite, G.; Pashkauskas, R.

    1995-01-01

    The investigations on 6 B group vitamins were carried out in the water of Lake Drukshiai in 1994. The results indicated that quantitative structure of the vitamins varied during seasons in different areas depths of the lake depending on the biomass of phytoplankton and their dominants. The vitamins balance characteristic to natural water basins was disturbed after the NPP operation. In summer of 1994 the amount of vitamins decreased and the deficit of biotin, thiamin and pyridoxine was observed to compare with 1992-1993. Therefore, the disturbance of stability in metabolic processes in which these vitamins take part may occur. (author). 11 refs., 2 tabs., 2 figs

  1. From myth to the individual: The dynamic process of cultural integration in groups of psychodrama in childhood

    Directory of Open Access Journals (Sweden)

    Angela Sordano

    2014-09-01

    Full Text Available This paper describes how the work methodology through the tale and psychodrama with children and adolescents focuses on the development of symbolic constructions figuratively organized which draw directly from the unconscious world of the participants and the mythic dimensions that organize their story. The psychodramatic group in childhood and adolescence may promote the social integration of people ethnically and culturally diverse through the recovery of those mythical and deep aspects that play a role in the unconscious of the individual.Keywords: Psychodrama; Adolescents; Mith

  2. Use of the SO(4,2) dynamical group for the study of the ground state of a hydrogen atom in a homogeneous magnetic field

    International Nuclear Information System (INIS)

    Cizek, J.; Vrscay, E.R.

    1977-01-01

    A perturbation procedure based on the use of the SO(4,2) dynamical group, which includes as its most important feature the nonunitary tilting transformation, is applied to the hydrogen atom system in a strong magnetic field and the terms ΔΣ/sub n/ were calculated to 40th order. The difficulty in using this approach is that the series has zero radius of convergence. Nevertheless, the Pade approximant technique may be used for the summation of the series. Surprising accuracy is found for the Pade estimate of the ionization energy. 5 references

  3. Group 1: Scenario design and development issues

    Science.gov (United States)

    Sherwin, P.

    1981-01-01

    All LOFT scenarios and flight segments should be designed on the basis of a detailed statement of specific objectives. These objectives must state what kind of situation is to be addressed and why. The origin, routing, and destination of a particular scenario should be dictated by the specific objectives for that scenario or leg. Other factors to be considered are the desired weather, climate, etc. Simulator visual system, as well as other capabilities and limitations must be considered at a very early stage of scenario design. The simulator navigation area must be apropriate and must coincide with current Jeppeson charts. Much of the realism of LOFT is destroyed if the crew is unable to use current manuals and other materials.

  4. The dynamic evolution of social ties and user-generated content: a case study on a Douban group

    Science.gov (United States)

    Shan, Siqing; Ren, Jie; Li, Cangyan

    2017-11-01

    As platforms based on user-generated content (UGC), social media platforms emphasise the social ties between users and user participation, which promote the communication and propagation of ideas and help to build and maintain relationships. However, many researchers have studied only predefined social networks, such as academic social networks. We believe that there are certain characteristics associated with the network's UGC worth evaluating. We conducted research in communities in which content attracts discussion and new members and examined the evolution patterns of social and content networks in a topic-oriented Douban group. Datasets of user and content information in communities of interest were collected through web crawler software. Networks based on social and content ties were constructed and analysed. We chose scale, density, centrality, average path length and cluster coefficient as measures for exploring the evolution and correlation of both types of networks. These findings are valuable for social media marketing and helpful in directing and controlling public opinion.

  5. The mental health treatment team as a work group: team dynamics and the role of the leader.

    Science.gov (United States)

    Yank, G R; Barber, J W; Hargrove, D S; Whitt, P D

    1992-08-01

    Although treatment teams have been examined often in the mental health literature, this literature seldom addresses the crucial property of "teamness"--the key set of intangible phenomena that allow a team to function synergistically as more than the sum of its parts, and with a sense of team identity. In this paper, the concept of the work group is used to develop a framework for understanding the factors contributing to effective team functioning and identity, an their implications for the tasks of team leadership and sociotherapy: "the art of maintaining a social system in which the treatment of an individual patient can best occur" (Edelson 1970). Leadership activities that promote team cohesiveness and boundary maintenance are discussed, and suggestions are provided for ways in which the subjective experiences and emotional reactions of the leader and team members can be used to promote improved task performance and clinical care.

  6. Population Dynamics Among six Major Groups of the Oryza rufipogon Species Complex, Wild Relative of Cultivated Asian Rice.

    Science.gov (United States)

    Kim, HyunJung; Jung, Janelle; Singh, Namrata; Greenberg, Anthony; Doyle, Jeff J; Tyagi, Wricha; Chung, Jong-Wook; Kimball, Jennifer; Hamilton, Ruaraidh Sackville; McCouch, Susan R

    2016-12-01

    Understanding population structure of the wild progenitor of Asian cultivated rice (O. sativa), the Oryza rufipogon species complex (ORSC), is of interest to plant breeders and contributes to our understanding of rice domestication. A collection of 286 diverse ORSC accessions was evaluated for nuclear variation using genotyping-by-sequencing (113,739 SNPs) and for chloroplast variation using Sanger sequencing (25 polymorphic sites). Six wild subpopulations were identified, with 25 % of accessions classified as admixed. Three of the wild groups were genetically and geographically closely related to the O. sativa subpopulations, indica, aus and japonica, and carried O. sativa introgressions; the other three wild groups were genetically divergent, had unique chloroplast haplotypes, and were located at the geographical extremes of the species range. The genetic subpopulations were significantly correlated (r 2  = 0.562) with traditional species designations, O. rufipogon (perennial) and O. nivara (annual), differentiated based on morphology and life history. A wild diversity panel of 95 purified (inbred) accessions was developed for future genetic studies. Our results suggest that the cultivated aus subpopulation is most closely related to an annual wild relative, japonica to a perennial wild relative, and indica to an admixed population of diverse annual and perennial wild ancestors. Gene flow between ORSC and O. sativa is common in regions where rice is cultivated, threatening the identity and diversity of wild ORSC populations. The three geographically isolated ORSC populations harbor variation rarely seen in cultivated rice and provide a unique window into the genetic composition of ancient rice subpopulations.

  7. Family Issues

    Science.gov (United States)

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

  8. Global Issues

    Energy Technology Data Exchange (ETDEWEB)

    Seitz, J.L.

    2001-10-15

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

  9. An Interaction of Economy and Environment in Dynamic Computable General Equilibrium Modeling with a Focus on Climate Change Issue in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Joh, S.H.; Chang, K.G.; Kim, Y.G.; Kang, S.I. [Korea Environment Institute, Seoul (Korea); Rob, D. [Wageningen University, Wageningen (Netherlands)

    2001-12-01

    In this study, the economic cost; of carbon taxes imposed on fossil fuels associated with climate change issue in Korea were analyzed based on the model of a small open-economy forward-looking dynamic CGE over the years 1998-2047. As a primary policy instrument, carbon taxes are imposed on coal, oil, and gas from year 2013 through 2047 from 100,000 Korean Won/ton of Carbon (TC) to KW400,000. The primary findings through this study are as follows: First, the primary economic indicators reflecting the results of sensitivity analysis through the study estimated that in the year 2025 at a carbon tax rate of 100,000KW/TC, the EVs span from -0.217% to -0.167% and the GDP changes from -0.195% to -0.432%, while the results from a rate of 400,000KW/TC were found to be -0.472% to -0.575% for EVs and -0.708% to - 1.525% for GDPs. Second, the reduction of emissions attributed to carbon tax rates of 100,000KW/TC equal 17(25) million TC which is 1.19(1.78) times the 2000 level in the year 2015(2035). In terms of GDP, the corresponding economic costs of the abatement are 1,261 billion Korean Won in 2015 and 4,551 KW in 2035. Third, the changes in GDP, resulting from sensitivity analysis, are almost identical with a tax rate of 100,000KW/TC and annual growth rate or 2{approx}3%. Thus, the change in GDP with a 3%(2%) growth rate were calculated to be -0.025%(-0.023%) in 2005, -0.176%(-0.176%) in 2015, -0.292%(-0.294%) in 2025, -0.347%(-0.350%) in 2035, and -0.371%(-0.374%) in 2045. In comparison to other Korean studies on carbon tax simulations, the results of this study found that there was no significant difference of the economic cost assessments in terms of GDP loss, overall; however, with increasing tax rates, the reduction in emissions in the present study were found to be less than those of previous ones. The following policy recommendations are suggested based on the results from this study: First, the carbon tax approach should be utilized to a limited extent. In the

  10. Diversification dynamics of rhynchostomatian ciliates: the impact of seven intrinsic traits on speciation and extinction in a microbial group.

    Science.gov (United States)

    Vďačný, Peter; Rajter, Ľubomír; Shazib, Shahed Uddin Ahmed; Jang, Seok Won; Shin, Mann Kyoon

    2017-08-30

    Ciliates are a suitable microbial model to investigate trait-dependent diversification because of their comparatively complex morphology and high diversity. We examined the impact of seven intrinsic traits on speciation, extinction, and net-diversification of rhynchostomatians, a group of comparatively large, predatory ciliates with proboscis carrying a dorsal brush (sensoric structure) and toxicysts (organelles used to kill the prey). Bayesian estimates under the binary-state speciation and extinction model indicate that two types of extrusomes and two-rowed dorsal brush raise diversification through decreasing extinction. On the other hand, the higher number of contractile vacuoles and their dorsal location likely increase diversification via elevating speciation rate. Particular nuclear characteristics, however, do not significantly differ in their diversification rates and hence lineages with various macronuclear patterns and number of micronuclei have similar probabilities to generate new species. Likelihood-based quantitative state diversification analyses suggest that rhynchostomatians conform to Cope's rule in that their diversity linearly grows with increasing body length and relative length of the proboscis. Comparison with other litostomatean ciliates indicates that rhynchostomatians are not among the cladogenically most successful lineages and their survival over several hundred million years could be associated with their comparatively large and complex bodies that reduce the risk of extinction.

  11. Group dynamic and its effect on classroom climate, achievement, and time in lab in the organic chemistry laboratory classroom

    Science.gov (United States)

    Hall, Rachael S.

    Despite the many studies on the benefits of cooperative learning, there is surprising little research into how the classroom as a whole changes when these cooperative groups are reassigned. In one section of CHEM 3011 in Fall 2013, students were allowed to pick their partner and kept the same partner all semester. In another section during the same semester, students were assigned a different partner for every wet lab and were allowed to pick their partners during the computer simulation labs. The students in both sections were given the "preferred" version of the Science Laboratory Environment Inventory (SLEI) at the beginning of the semester to elicit student preferences for the class environment, and the "actual" version of the SLEI and the Class Life Instrument at the end of the semester to determine what actually occurred during the semester. The students' interactions were recorded using an observational instrument developed specifically for this project. The students' responses to surveys, interactions, grades, and time in lab were analyzed for differences between the two sections. The results of this study will be discussed.

  12. Spatial and temporal changes in group dynamics and range use enable anti-predator responses in African buffalo.

    Science.gov (United States)

    Tambling, Craig J; Druce, Dave J; Hayward, Matt W; Castley, J Guy; Adendorff, John; Kerley, Graham I H

    2012-06-01

    The reintroduction of large predators provides a framework to investigate responses by prey species to predators. Considerable research has been directed at the impact that reintroduced wolves (Canis lupus) have on cervids, and to a lesser degree, bovids, in northern temperate regions. Generally, these impacts alter feeding, activity, and ranging behavior, or combinations of these. However, there are few studies on the response of African bovids to reintroduced predators, and thus, there is limited data to compare responses by tropical and temperate ungulates to predator reintroductions. Using the reintroduction of lion (Panthera leo) into the Addo Elephant National Park (AENP) Main Camp Section, South Africa, we show that Cape buffalo (Syncerus caffer) responses differ from northern temperate ungulates. Following lion reintroduction, buffalo herds amalgamated into larger, more defendable units; this corresponded with an increase in the survival of juvenile buffalo. Current habitat preference of buffalo breeding herds is for open habitats, especially during the night and morning, when lion are active. The increase in group size and habitat preference countered initial high levels of predation on juvenile buffalo, resulting in a return in the proportion of juveniles in breeding herds to pre-lion levels. Our results show that buffalo responses to reintroduced large predators in southern Africa differ to those of northern temperate bovids or cervids in the face of wolf predation. We predict that the nature of the prey response to predator reintroduction is likely to reflect the trade-off between the predator selection and hunting strategy of predators against the life history and foraging strategies of each prey species.

  13. Nonclassical dynamics of the methyl group in 1,1,1-triphenylethane. Evidence from powder 1H NMR spectra

    KAUST Repository

    Osior, Agnieszka

    2017-03-14

    According to the damped quantum rotation (DQR) theory, hindered rotation of methyl groups, evidenced in nuclear magnetic resonance (NMR) line shapes, is a nonclassical process. It comprises a number of quantum-rate processes measured by two different quantum-rate constants. The classical jump model employing only one rate constant is reproduced if these quantum constants happen to be equal. The values of their ratio, or the nonclassicallity coefficient, determined hitherto from NMR spectra of single crystals and solutions range from about 1.20 to 1.30 in the latter case to above 5.0 in the former, with the value of 1 corresponding to the jump model. Presently, first systematic investigations of the DQR effects in wide-line NMR spectra of a powder sample are reported. For 1,1,1-triphenylethane deuterated in the aromatic positions, the relevant line-shape effects were monitored in the range 99–121 K. The values of the nonclassicality coefficient dropping from 2.7 to 1.7 were evaluated in line shape fits to the experimental powder spectra from the range 99–108 K. At these temperatures, the fits with the conventional line-shape model are visibly inferior to the DQR fits. Using a theoretical model reported earlier, a semiquantitative interpretation of the DQR parameters evaluated from the spectra is given. It is shown that the DQR effects as such can be detected in wide-line NMR spectra of powdered samples, which are relatively facile to measure. However, a fully quantitative picture of these effects can only be obtained from the much more demanding experiments on single crystals.

  14. Filamentation and light bullet formation dynamics in solid-state dielectric media with weak, moderate and strong anomalous group velocity dispersion

    International Nuclear Information System (INIS)

    Gražulevičiūtė, I; Garejev, N; Majus, D; Tamošauskas, G; A Dubietis; Jukna, V

    2016-01-01

    We present a series of measurements, which characterize filamentation dynamics of intense ultrashort laser pulses in the space–time domain, as captured by means of three-dimensional imaging technique in sapphire and fused silica, in the wavelength range of 1.45–2.25 μm, accessing the regimes of weak, moderate and strong anomalous group velocity dispersion (GVD). In the regime of weak anomalous GVD (at 1.45 μm), pulse splitting into two sub-pulses producing a pair of light bullets with spectrally shifted carrier frequencies in both nonlinear media is observed. In contrast, in the regimes of moderate (at 1.8 μm) and strong (at 2.25 μm) anomalous GVD we observe notably different transient dynamics, which however lead to the formation of a single self-compressed quasistationary light bullet with an universal spatiotemporal shape comprised of an extended ring-shaped periphery and a localized intense core that carries the self-compressed pulse. (paper)

  15. Filamentation and light bullet formation dynamics in solid-state dielectric media with weak, moderate and strong anomalous group velocity dispersion

    Science.gov (United States)

    Gražulevičiūtė, I.; Garejev, N.; Majus, D.; Jukna, V.; Tamošauskas, G.; Dubietis, A.

    2016-02-01

    We present a series of measurements, which characterize filamentation dynamics of intense ultrashort laser pulses in the space-time domain, as captured by means of three-dimensional imaging technique in sapphire and fused silica, in the wavelength range of 1.45-2.25 μm, accessing the regimes of weak, moderate and strong anomalous group velocity dispersion (GVD). In the regime of weak anomalous GVD (at 1.45 μm), pulse splitting into two sub-pulses producing a pair of light bullets with spectrally shifted carrier frequencies in both nonlinear media is observed. In contrast, in the regimes of moderate (at 1.8 μm) and strong (at 2.25 μm) anomalous GVD we observe notably different transient dynamics, which however lead to the formation of a single self-compressed quasistationary light bullet with an universal spatiotemporal shape comprised of an extended ring-shaped periphery and a localized intense core that carries the self-compressed pulse.

  16. Volume 90, Issue1 (February 2005)Articles in the Current Issue:Original PaperSeasonal Dynamics of Benthic and Planktonic Algae in a Nutrient-Rich Lowland River (Spree, Germany)

    Science.gov (United States)

    Werner, Petra; Köhler, Jan

    2005-02-01

    We studied chlorophyll a (chl. a), biovolume and species composition of benthic algae and phytoplankton in the eutrophic lower River Spree in 1996. The chl. a concentration was estimated as 3.5 (2.7-4.5) μg/cm2 for epipsammon, 9.4 (7.4-11.9) μg/cm2 for epipelon and 6.7 (5.7-7.8) μg/cm2 for the epilithon (median and 95% C. L.). The mean total biomass of benthic algae was significantly higher (6.0 μg chl. a/cm2) than the areal chl. a content of the pelagic zone (1.6 μg chl. a/cm2). Although certain phytoplankton taxa were abundant in the periphyton, benthic taxa generally dominated the assemblages. Seasonal dynamics of benthic algae were probably controlled by light and nitrate supply (sand), discharge fluctuations (sand, mud) and invertebrate grazing (stones). This paper shows the importance of benthic algae even in phytoplankton-rich lowland rivers with sandy or muddy sediments.

  17. The organization and evolution of the Responder satellite in species of the Drosophila melanogaster group: dynamic evolution of a target of meiotic drive.

    Science.gov (United States)

    Larracuente, Amanda M

    2014-11-25

    Satellite DNA can make up a substantial fraction of eukaryotic genomes and has roles in genome structure and chromosome segregation. The rapid evolution of satellite DNA can contribute to genomic instability and genetic incompatibilities between species. Despite its ubiquity and its contribution to genome evolution, we currently know little about the dynamics of satellite DNA evolution. The Responder (Rsp) satellite DNA family is found in the pericentric heterochromatin of chromosome 2 of Drosophila melanogaster. Rsp is well-known for being the target of Segregation Distorter (SD)- an autosomal meiotic drive system in D. melanogaster. I present an evolutionary genetic analysis of the Rsp family of repeats in D. melanogaster and its closely-related species in the melanogaster group (D. simulans, D. sechellia, D. mauritiana, D. erecta, and D. yakuba) using a combination of available BAC sequences, whole genome shotgun Sanger reads, Illumina short read deep sequencing, and fluorescence in situ hybridization. I show that Rsp repeats have euchromatic locations throughout the D. melanogaster genome, that Rsp arrays show evidence for concerted evolution, and that Rsp repeats exist outside of D. melanogaster, in the melanogaster group. The repeats in these species are considerably diverged at the sequence level compared to D. melanogaster, and have a strikingly different genomic distribution, even between closely-related sister taxa. The genomic organization of the Rsp repeat in the D. melanogaster genome is complex-it exists of large blocks of tandem repeats in the heterochromatin and small blocks of tandem repeats in the euchromatin. My discovery of heterochromatic Rsp-like sequences outside of D. melanogaster suggests that SD evolved after its target satellite and that the evolution of the Rsp satellite family is highly dynamic over a short evolutionary time scale (<240,000 years).

  18. Dips spacecraft integration issues

    International Nuclear Information System (INIS)

    Determan, W.R.; Harty, R.B.

    1988-01-01

    The Department of Energy, in cooperation with the Department of Defense, has recently initiated the dynamic isotope power system (DIPS) demonstration program. DIPS is designed to provide 1 to 10 kW of electrical power for future military spacecraft. One of the near-term missions considered as a potential application for DIPS was the boost surveillance and tracking system (BSTS). A brief review and summary of the reasons behind a selection of DIPS for BSTS-type missions is presented. Many of these are directly related to spacecraft integration issues; these issues will be reviewed in the areas of system safety, operations, survivability, reliability, and autonomy

  19. Summary, Working Group 1: Electron guns and injector designs

    International Nuclear Information System (INIS)

    Ben-Zvi, I.; Bazarov, I.V.

    2006-01-01

    We summarize the proceedings of Working Group 1 of the 2005 Energy Recovery Linac (ERL) Workshop. The subject of this working group, the electron gun and injector design, is arguably the most critical part of the ERL as it determines the ultimate performance of this type of accelerators. Working Group 1 dealt with a variety of subjects: The technology of DC, normal-conducting RF and superconducting RF guns; beam dynamics in the gun and injector; the cathode and laser package; modeling and computational issues; magnetized beams and polarization. A short overview of these issues covered in the Working Group is presented in this paper

  20. Design study of beam dynamics issues for 1 TeV next linear collider based upon the relativistic-klystron two-beam accelerator

    International Nuclear Information System (INIS)

    Li, H.; Goffeney, N.; Henestroza, E.; Sessler, A.; Yu, S.; Houck, T.; Westenskow, G.

    1994-11-01

    A design study has recently been conducted for exploring the feasibility of a relativistic-klystron two-beam accelerator (RK-TBA) system as a rf power source for a 1 TeV linear collider. The author present, in this paper, the beam dynamics part of this study. They have achieved in their design study acceptable transverse and longitudinal beam stability properties for the resulting high efficiency and low cost RK-TBA

  1. Workforce Issues.

    Science.gov (United States)

    1996

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

  2. Sanskrit Issue.

    Science.gov (United States)

    Miller, Barbara Stoler, Ed.

    1971-01-01

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

  3. Bond Issues.

    Science.gov (United States)

    Pollack, Rachel H.

    2000-01-01

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

  4. Theoretical Issues

    Energy Technology Data Exchange (ETDEWEB)

    Marc Vanderhaeghen

    2007-04-01

    The theoretical issues in the interpretation of the precision measurements of the nucleon-to-Delta transition by means of electromagnetic probes are highlighted. The results of these measurements are confronted with the state-of-the-art calculations based on chiral effective-field theories (EFT), lattice QCD, large-Nc relations, perturbative QCD, and QCD-inspired models. The link of the nucleon-to-Delta form factors to generalized parton distributions (GPDs) is also discussed.

  5. Transmission issues

    International Nuclear Information System (INIS)

    Bradford, J.; Wilson, L.; Thon, S.; Millar, N.

    2005-01-01

    This session on transmission issues focused on the role that transmission plays in electricity markets and the importance of getting the market structure right in terms of generation divestiture with buy back contracts, demand side responsive programs, transmission upgrades and long term contracts. The difficulties of distinguishing between market power and scarcity were examined along with some of the complications that ensue if transmission experiences congestion, as exemplified by the August 2003 blackout in eastern North America. The presentations described the best ways to handle transmission issues, and debated whether transmission should be deregulated or follow market forces. Issues of interconnections and reliability of connections were also debated along with the attempt to integrate renewables into the grid. Some presentations identified what new transmission must be built and what must be done to ensure that transmission gets built. The challenges and business opportunities for transmission in Alberta were discussed with reference to plans to invest in new infrastructure, where it is going outside of the province and how it works with other jurisdictions. Manitoba's Conawapa Hydro Project and its 2000 MW tie line to Ontario was also discussed. Some examples of non-optimal use of interconnections in Europe were also discussed in an effort to learn from these mistakes and avoid them in Canada. tabs., figs

  6. Miscellaneous issues

    International Nuclear Information System (INIS)

    2002-01-01

    The New Brunswick Market Design Committee has examined several issues regarding the restructuring of the province's electricity sector. This report presents issues that require guidance for implementation, with particular focus on options available for their resolutions. The issues include: (1) rate principles for stranded offer service (SOS) supply, (2) the ability of contestable customers to return to SOS after having left it, (3) whether loads embedded in distribution systems are eligible to participate in the bilateral contract market, (4) whether generators or suppliers can offer capacity and energy to SOS suppliers in competition with the SOS supplier, and (5) details for the balancing market, including pricing, bidding protocols, settlements and how intermittent power sources can participate in the market. A section on pricing for SOS explains pricing principles, the use of export profits, pricing for SOS capacity, and time of use pricing. The Committee has made recommendations for the electricity system in the province to have an energy imbalance service that can move towards a market in order to develop an efficient and effective service. This report also explains pricing in the balancing market, penalties, and settlements. 7 refs

  7. Interagency mechanical operations group numerical systems group

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-09-01

    This report consists of the minutes of the May 20-21, 1971 meeting of the Interagency Mechanical Operations Group (IMOG) Numerical Systems Group. This group looks at issues related to numerical control in the machining industry. Items discussed related to the use of CAD and CAM, EIA standards, data links, and numerical control.

  8. Canada's domestic nuclear issues

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    The Interfaith Program for Public Awareness of Nuclear Issues (IPPANI) is a committee of representatives of religious groups in Toronto, a group of people concerned about the moral and ethical implications of the operation of Canada's nuclear industry and of its exports to other countries. The faith groups represented are the Anglican Diocese of Toronto, the Baha'i Community of Canada, the Jewish Community of Toronto, the Roman Catholic Archdiocese of Toronto and the United Church of Canada Toronto Conference. Wishing to encourage the Canadian government to enquire into this broad question, the faith groups established IPPANI and assigned to it the task of enhancing their knowledge of the nuclear industry. IPPANI was to develop an effective set of questions to be placed before governments and to promote public discussion so that governments might become more responsive to these issues

  9. Na/Ca Intermixing around Silicate and Phosphate Groups in Bioactive Phosphosilicate Glasses Revealed by Heteronuclear Solid-State NMR and Molecular Dynamics Simulations.

    Science.gov (United States)

    Mathew, Renny; Stevensson, Baltzar; Edén, Mattias

    2015-04-30

    We characterize the intermixing of network-modifying Na(+)/Ca(2+) ions around the silicate (QSi(n)) and phosphate (QP(n)) tetrahedra in a series of 16 Na2O–CaO–SiO2–P2O5 glasses, whose P content and silicate network connectivity were varied independently. The set includes both bioactive and bioinactive compositions and also encompasses two soda-lime-silicate members devoid of P, as well as two CaO–SiO2 glasses and one Na2O–SiO2–P2O5 glass. The various Si/P↔Na/Ca contacts were probed by molecular dynamics (MD) simulations together with heteronuclear magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) experimentation utilizing (23)Na{(31)P} and (23)Na{(29)Si} REDOR, as well as (31)P{ (23)Na} and (29)Si{(23)Na} REAPDOR. We introduce an approach for quantifying the extent of Na(+)/Ca(2+) ordering around a given QP(n) or QSi(n) group, encoded by the preference factor 0⩽ PM ⩽ 1 conveying the relative weights of a random cation intermixing (PM = 0) and complete preference/ordering (PM = 1) for one of the species M, which represents either Na(+) or Ca(2+). The MD-derived preference factors reveal phosphate and silicate species surrounded by Na(+)/Ca(2+) ions intermixed nearly randomly (PM ≲ 0.15), except for the QSi(4) and QSi(1) groups, which manifest more significant cation ordering with preference for Na+ and Ca2+, respectively. The overall weak preferences are essentially independent of the Si and P contents of the glass, whereas PM primarily correlates with the total amount of network modifiers: as the latter is increased, the Na/Ca distribution around the {QP(0), QSi(1), QSi(2)} groups with preference for Ca2(+ )tend to randomize (i.e., PCa decreases), while the PNa-values grow slightly for the {QP(1), QSi(3), QSi(4)} species already preferring coordination of Na. The set of experimental preference factors {PCa} for the orthophosphate (QP(0)) groups extracted from (31)P{(23)Na} REAPDOR NMR-derived M2(P–Na) dipolar second moments agrees

  10. Worker Safety and Health Issues Associated with the DOE Environmental Cleanup Program: Insights From the DOE Laboratory Directors' Environmental and Occupational/Public health Standards Steering Group

    Energy Technology Data Exchange (ETDEWEB)

    M.C. Edelson; Samuel C. Morris; Joan M. Daisey

    2001-03-01

    The U.S. Department of Energy (DOE) Laboratory Directors' Environmental and Occupational/Public Health Standards Steering Group (or ''SSG'') was formed in 1990. It was felt then that ''risk'' could be an organizing principle for environmental cleanup and that risk-based cleanup standards could rationalize clean up work. The environmental remediation process puts workers engaged in cleanup activities at risk from hazardous materials and from the more usual hazards associated with construction activities. In a real sense, the site remediation process involves the transfer of a hypothetical risk to the environment and the public from isolated contamination into real risks to the workers engaged in the remediation activities. Late in its existence the SSG, primarily motivated by its LANL representative, Dr. Harry Ettinger, actively investigated issues associated with worker health and safety during environmental remediation activities. This paper summarizes the insights noted by the SSG. Most continue to be pertinent today.

  11. Health service resilience in Yobe state, Nigeria in the context of the Boko Haram insurgency: a systems dynamics analysis using group model building.

    Science.gov (United States)

    Ager, Alastair K; Lembani, Martina; Mohammed, Abdulaziz; Mohammed Ashir, Garba; Abdulwahab, Ahmad; de Pinho, Helen; Delobelle, Peter; Zarowsky, Christina

    2015-01-01

    Yobe State has faced severe disruption of its health service as a result of the Boko Haram insurgency. A systems dynamics analysis was conducted to identify key pathways of threat to provision and emerging pathways of response and adaptation. Structured interviews were conducted with 39 stakeholders from three local government areas selected to represent the diversity of conflict experience across the state: Damaturu, Fune and Nguru, and with four officers of the PRRINN-MNCH program providing technical assistance for primary care development in the state. A group model building session was convened with 11 senior stakeholders, which used participatory scripts to review thematic analysis of interviews and develop a preliminary systems model linking identified variables. Population migration and transport restrictions have substantially impacted access to health provision. The human resource for health capability of the state has been severely diminished through the outward migration of (especially non-indigenous) health workers and the suspension of programmes providing external technical assistance. The political will of the Yobe State government to strengthen health provision - through lifting a moratorium on recruitment and providing incentives for retention and support of staff - has supported a recovery of health systems functioning. Policies of free-drug provision and decentralized drug supply appear to have been protective of the operation of the health system. Community resources and cohesion have been significant assets in combatting the impacts of the insurgency on service utilization and quality. Staff commitment and motivation - particularly amongst staff indigenous to the state - has protected health care quality and enabled flexibility of human resource deployment. A systems analysis using participatory group model building provided a mechanism to identify key pathways of threat and adaptation with regard to health service functioning. Generalizable

  12. Report of the consultants' meeting on the identification of research needs for quantification of nutrient dynamics in integrated crop/livestock systems with a focus on conservation and sustainability issues in developing countries

    International Nuclear Information System (INIS)

    2002-01-01

    A Consultants' Meeting on 'The identification of research needs for quantification of nutrient needs for quantification of nutrient dynamics in integrated crop/livestock systems with a focus on conservation and sustainability issues in developing countries' was held at IAEA, Vienna, April 12- 14, 2000. Four consultants, with expertise in nutrient dynamics drawn from National Agricultural Research Organisations and Universities, attended the meeting together with staff members of the Joint FAO/IAEA Divisions. The consultants presented reviews of the situation regarding studies of nutrient dynamics in crop/pasture/ livestock systems in developing and developed agricultural systems. These were complemented by a paper on the development of 15 N techniques to study the contribution of N from crop residues and human, animal and industrial waste products developed at the Seibersdorf Laboratory. The consultants were of the opinion that in view of of the Joint FAO/IAEA Division's comparative advantage in operating (both technically and administratively) Coordinated Research Projects (CRPs) the proposal to initiate an FAO/IAEA CRP on quantification of nutrient budget and flows in integrated crop/livestock systems is appropriate. They identified a well focused area of the CRP and also provided recommendations on its formulation and implementation

  13. Report of the consultants' meeting on the identification of research needs for quantification of nutrient dynamics in integrated crop/livestock systems with a focus on conservation and sustainability issues in developing countries

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    A Consultants' Meeting on 'The identification of research needs for quantification of nutrient needs for quantification of nutrient dynamics in integrated crop/livestock systems with a focus on conservation and sustainability issues in developing countries' was held at IAEA, Vienna, April 12- 14, 2000. Four consultants, with expertise in nutrient dynamics drawn from National Agricultural Research Organisations and Universities, attended the meeting together with staff members of the Joint FAO/IAEA Divisions. The consultants presented reviews of the situation regarding studies of nutrient dynamics in crop/pasture/ livestock systems in developing and developed agricultural systems. These were complemented by a paper on the development of {sup 15}N techniques to study the contribution of N from crop residues and human, animal and industrial waste products developed at the Seibersdorf Laboratory. The consultants were of the opinion that in view of of the Joint FAO/IAEA Division's comparative advantage in operating (both technically and administratively) Coordinated Research Projects (CRPs) the proposal to initiate an FAO/IAEA CRP on quantification of nutrient budget and flows in integrated crop/livestock systems is appropriate. They identified a well focused area of the CRP and also provided recommendations on its formulation and implementation.

  14. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2017-10-05

    Oct 5, 2017 ... culture of Mamak frequenting restaurants in Malaysia, several issue has risen in relation to the .... employment of one group quasi experimental design was noted to be lacked in internal ... Food safety and quality division: ... self-reported practices of food service staff regarding food hygiene in Edirne, Turkey ...

  15. Development of a group contribution method for estimating free energy of peptides in a dodecane-water system via molecular dynamic simulations.

    Science.gov (United States)

    Mora Osorio, Camilo Andrés; González Barrios, Andrés Fernando

    2016-12-07

    Calculation of the Gibbs free energy changes of biological molecules at the oil-water interface is commonly performed with Molecular Dynamics simulations (MD). It is a process that could be performed repeatedly in order to find some molecules of high stability in this medium. Here, an alternative method of calculation has been proposed: a group contribution method (GCM) for peptides based on MD of the twenty classic amino acids to obtain free energy change during the insertion of any peptide chain in water-dodecane interfaces. Multiple MD of the twenty classic amino acids located at the interface of rectangular simulation boxes with a dodecane-water medium were performed. A GCM to calculate the free energy of entire peptides is then proposed. The method uses the summation of the Gibbs free energy of each amino acid adjusted in function of its presence or absence in the chain as well as its hydrophobic characteristics. Validation of the equation was performed with twenty-one peptides all simulated using MD in dodecane-water rectangular boxes in previous work, obtaining an average relative error of 16%.

  16. Identification of Novel Proteins Co-Purifying with Cockayne Syndrome Group B (CSB Reveals Potential Roles for CSB in RNA Metabolism and Chromatin Dynamics.

    Directory of Open Access Journals (Sweden)

    Serena Nicolai

    Full Text Available The CSB protein, a member of the SWI/SNF ATP dependent chromatin remodeling family of proteins, plays a role in a sub-pathway of nucleotide excision repair (NER known as transcription coupled repair (TCR. CSB is frequently mutated in Cockayne syndrome group B, a segmental progeroid human autosomal recessive disease characterized by growth failure and degeneration of multiple organs. Though initially classified as a DNA repair protein, recent studies have demonstrated that the loss of CSB results in pleiotropic effects. Identification of novel proteins belonging to the CSB interactome may be useful not only for predicting the molecular basis for diverse pathological symptoms of CS-B patients but also for unraveling the functions of CSB in addition to its authentic role in DNA repair. In this study, we performed tandem affinity purification (TAP technology coupled with mass spectrometry and co-immunoprecipitation studies to identify and characterize the proteins that potentially interact with CSB-TAP. Our approach revealed 33 proteins that were not previously known to interact with CSB. These newly identified proteins indicate potential roles for CSB in RNA metabolism involving repression and activation of transcription process and in the maintenance of chromatin dynamics and integrity.

  17. USSR Space Life Sciences Digest, issue 19

    Science.gov (United States)

    Hooke, Lydia Razran (Editor); Donaldson, P. Lynn (Editor); Teeter, Ronald (Editor); Garshnek, Victoria (Editor); Rowe, Joseph (Editor)

    1988-01-01

    This is the 19th issue of NASA's USSR Space Life Sciences Digest. It contains abstracts of 47 papers published in Russian language periodicals or presented at conferences and of 5 new Soviet monographs. Selected abstracts are illustrated with figures and tables from the original. Reports on two conferences, one on adaptation to high altitudes, and one on space and ecology are presented. A book review of a recent work on high altitude physiology is also included. The abstracts in this issue have been identified as relevant to 33 areas of space biology and medicine. These areas are: adaptation, biological rhythms, biospherics, body fluids, botany, cardiovascular and respiratory systems, cytology, developmental biology, endocrinology, enzymology, biology, group dynamics, habitability and environmental effects, hematology, human performance, immunology, life support systems, man-machine systems, mathematical modeling, metabolism, microbiology, musculoskeletal system, neurophysiology, nutrition, operational medicine, perception, personnel selection, psychology, radiobiology, and space biology and medicine.

  18. USSR Space Life Sciences Digest, Issue 18

    Science.gov (United States)

    Hooke, Lydia Razran (Editor); Donaldson, P. Lynn (Editor); Teeter, Ronald (Editor); Garshnek, Victoria (Editor); Rowe, Joseph (Editor)

    1988-01-01

    This is the 18th issue of NASA's USSR Life Sciences Digest. It contains abstracts of 50 papers published in Russian language periodicals or presented at conferences and of 8 new Soviet monographs. Selected abstracts are illustrated with figures and tables from the original. A review of a recent Aviation Medicine Handbook is also included. The abstracts in this issue have been identified as relevant to 37 areas of space biology and medicine. These areas are: adaptation, aviation medicine, biological rhythms, biospherics, body fluids, cardiovascular and respiratory systems, cytology, developmental biology, endocrinology, enzymology, equipment and instrumentation, exobiology, gastrointestinal system, genetics, gravitational biology, group dynamics, habitability and environmental effects, hematology, human performance, immunology, life support systems, man-machine systems, mathematical modeling, metabolism, microbiology, musculoskeletal system, neurophysiology, nutrition, operational medicine, perception, personnel selection, psychology, radiobiology, reproductive biology, space biology and medicine, and space industrialization.

  19. USSR Space Life Sciences Digest, issue 11

    Science.gov (United States)

    Hooke, Lydia Razran (Editor); Radtke, Mike (Editor); Radtke, Mike (Editor); Radtke, Mike (Editor); Radtke, Mike (Editor); Radtke, Mike (Editor)

    1987-01-01

    This is the eleventh issue of NASA's USSR Space Life Sciences Digest. It contains abstracts of 54 papers recently published in Russian language periodicals and bound collections and of four new Soviet monographs. Selected abstracts are illustrated. Additional features include the translation of a paper presented in Russian to the United Nations, a review of a book on space ecology, and report of a conference on evaluating human functional capacities and predicting health. Current Soviet Life Sciences titles available in English are cited. The materials included in this issue have been identified as relevant to 30 areas of aerospace medicine and space biology. These areas are: adaptation, aviation physiology, biological rhythms, biospherics, body fluids, botany, cardiovascular and respiratory systems, cosmonaut training, developmental biology, endocrinology, enzymology, equipment and instrumentation, gastrointestinal systems, group dynamics, genetics, hematology, human performance, immunology, life support systems, mathematical modeling, metabolism, microbiology, musculoskeletal system, neurophysiology, nutrition, operational medicine, perception, personnel selection, psychology, and radiobiology.

  20. Student leadership in small group science inquiry

    Science.gov (United States)

    Oliveira, Alandeom W.; Boz, Umit; Broadwell, George A.; Sadler, Troy D.

    2014-09-01

    Background: Science educators have sought to structure collaborative inquiry learning through the assignment of static group roles. This structural approach to student grouping oversimplifies the complexities of peer collaboration and overlooks the highly dynamic nature of group activity. Purpose: This study addresses this issue of oversimplification of group dynamics by examining the social leadership structures that emerge in small student groups during science inquiry. Sample: Two small student groups investigating the burning of a candle under a jar participated in this study. Design and method: We used a mixed-method research approach that combined computational discourse analysis (computational quantification of social aspects of small group discussions) with microethnography (qualitative, in-depth examination of group discussions). Results: While in one group social leadership was decentralized (i.e., students shared control over topics and tasks), the second group was dominated by a male student (centralized social leadership). Further, decentralized social leadership was found to be paralleled by higher levels of student cognitive engagement. Conclusions: It is argued that computational discourse analysis can provide science educators with a powerful means of developing pedagogical models of collaborative science learning that take into account the emergent nature of group structures and highly fluid nature of student collaboration.