WorldWideScience

Sample records for dynamical groups

  1. Supervision and group dynamics

    DEFF Research Database (Denmark)

    Hansen, Søren; Jensen, Lars Peter

    2004-01-01

    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...... 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...

  2. Group Dynamic Processes in Email Groups

    Science.gov (United States)

    Alpay, Esat

    2005-01-01

    Discussion is given on the relevance of group dynamic processes in promoting decision-making in email discussion groups. General theories on social facilitation and social loafing are considered in the context of email groups, as well as the applicability of psychodynamic and interaction-based models. It is argued that such theories may indeed…

  3. Symbolic dynamics and hyperbolic groups

    CERN Document Server

    Coornaert, Michel

    1993-01-01

    Gromov's theory of hyperbolic groups have had a big impact in combinatorial group theory and has deep connections with many branches of mathematics suchdifferential geometry, representation theory, ergodic theory and dynamical systems. This book is an elaboration on some ideas of Gromov on hyperbolic spaces and hyperbolic groups in relation with symbolic dynamics. Particular attention is paid to the dynamical system defined by the action of a hyperbolic group on its boundary. The boundary is most oftenchaotic both as a topological space and as a dynamical system, and a description of this boundary and the action is given in terms of subshifts of finite type. The book is self-contained and includes two introductory chapters, one on Gromov's hyperbolic geometry and the other one on symbolic dynamics. It is intended for students and researchers in geometry and in dynamical systems, and can be used asthe basis for a graduate course on these subjects.

  4. 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

  5. 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

  6. Topological dynamics and definable groups

    CERN Document Server

    Pillay, Anand

    2012-01-01

    Following the works of Newelski we continue the study of the relations between abstract topological dynamics and generalized stable group theory. We show that the Ellis theory, applied to the action of G(M) on its type space, for G an fsg group in a NIP theory, and M any model, yields the quotient G/G^00.

  7. Play and Positive Group Dynamics

    Science.gov (United States)

    Thompson, Pam; White, Samantha

    2010-01-01

    Play is an important part of a child's life and essential to learning and development (Vygotsky, 1978). It is vital that students participate in play and that play be conducted in a restorative manner. Play allows a variety of group dynamics to emerge. Irvin Yalom (1995) identifies 11 curative factors of the group experience. These factors include…

  8. Modelling group dynamic animal movement

    DEFF Research Database (Denmark)

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

    2014-01-01

    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......, 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...... 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...

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

    Science.gov (United States)

    1990-05-15

    TOTAL QUALITY MANAGEMENT (TQM) Group Dynamics Workshop © Copyright 1990 Booz*Allen & Hamilton... QUALITY MANAGEMENT (TQM) GROUP DYNAMICS COURSE -’ Total Quality Management * This course has been designed under the direction and approval of OASD (P...participants’ use of group dynamics skills as leaders and members of OSD TQM groups. Total Quality Management " Examples of such groups include

  10. Organisations’ evolutionary dynamics: a group dynamics approach

    Directory of Open Access Journals (Sweden)

    Germán Eduardo Vargas

    2010-04-01

    Full Text Available Colombian entrepreneurs’ straggling, reactionary and inertial orientation has been inconsistently lustified by the availability of internal and leveraged resources, a concept intensifying deficient technological capacity. Company activity (seen as being a socioeconomic unit has been integrally orientated within an evolutionary framework by company identity and cohesion as well as adaptation and evolutionary mechanisms. The present document uses a group dynamics’ model to illustrate how knowledge-based strategic orientation and integration for innovation have become an imperative for development, from slight leverage, distinguishing between two evolutionary company forms: traditional economic (inertial, as they introduce sporadic incremental improvements and modern companies (dynamic and radical innovators. Revealing conclusions obtained from such model may be used for intervening in and modernising company activity.

  11. Evolutionary dynamics of group fairness.

    Science.gov (United States)

    Santos, Fernando P; Santos, Francisco C; Paiva, Ana; Pacheco, Jorge M

    2015-08-07

    The emergence and impact of fairness is commonly studied in the context of 2-person games, notably the Ultimatum Game. Often, however, humans face problems of collective action involving more than two individuals where fairness is known to play a very important role, and whose dynamics cannot be inferred from what is known from 2-person games. Here, we propose a generalization of the Ultimatum Game for an arbitrary number of players--the Multiplayer Ultimatum Game. Proposals are made to a group of responders who must individually reject or accept the proposal. If the total number of individual acceptances stands below a given threshold, the offer will be rejected; otherwise, the offer will be accepted, and equally shared by all responders. We investigate the evolution of fairness in populations of individuals by means of evolutionary game theory, providing both analytical insights and results from numerical simulations. We show how imposing stringent consensuses significantly increases the value of the proposals, leading to fairer outcomes and more tolerant players. Furthermore, we show how stochastic effects--such as imitation errors and/or errors when assessing the fitness of others--may further enhance the overall success in reaching fair collective action. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. A New Dynamic Group Signature Scheme

    Institute of Scientific and Technical Information of China (English)

    HE Yefeng

    2006-01-01

    In this paper, a new dynamic group signature scheme is proposed. It allows the group manager to increase or delete group members flexibly. Furthermore, the length of group signatures, as well as the computational effort for signing, verifying and opening are very small and independent of the number of group members and deleted group members. So it is efficient.

  13. Group dynamics basics and pragmatics for practitioners

    CERN Document Server

    Haynes, Norris M

    2012-01-01

    This book provides a clear and engaging description of group dynamic processes. Group Dynamics will serve as an important text for students and professors and as a valuable guide for those who facilitate groups in a variety of clinical, counseling, educational, research, and organizational settings.

  14. Decision Dynamics in Group Evacuation

    CERN Document Server

    Han, Fangqiu; Schlesinger, Kimberly J; Gür, Izzeddin; Carlson, Jean M

    2016-01-01

    Identifying factors that affect human decision making and quantifying their influence remain essential and challenging tasks for the design and implementation of social and technological communication systems. We report results of a behavioral experiment involving decision making in the face of an impending natural disaster. In a controlled laboratory setting, we characterize individual and group evacuation decision making influenced by several key factors, including the likelihood of the disaster, available shelter capacity, group size, and group decision protocol. Our results show that success in individual decision making is not a strong predictor of group performance. We use an artificial neural network trained on the collective behavior of subjects to predict individual and group outcomes. Overall model accuracy increases with the inclusion of a subject-specific performance parameter based on laboratory trials that captures individual differences. In parallel, we demonstrate that the social media activit...

  15. 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.

  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. 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.

  18. Dynamics of the Local Group.

    Science.gov (United States)

    Moore, B.; Frenk, C.

    The authors have analysed in detail the properties of a binary system formed in an N-body simulation of a cold dark matter Universe described by Frenk et al., 1985. The internal structure and orbital parameters of this system resemble those of the Local Group.

  19. Diffusion processes through social groups' dynamics

    CERN Document Server

    Apolloni, Andrea

    2011-01-01

    Axelrod's model describes the dissemination of a set of cultural traits in a society constituted by individual agents. In a social context, nevertheless, individual choices toward a specific attitude are also at the basis of the formation of communities, groups and parties. The membership in a group changes completely the behavior of single agents who start acting according to a social identity. Groups act and interact among them as single entities, but still conserve an internal dynamics. We show that, under certain conditions of social dynamics, the introduction of group dynamics in a cultural dissemination process avoids the flattening of the culture into a single entity and preserves the multiplicity of cultural attitudes. We also considered diffusion processes on this dynamical background, showing the conditions under which information as well as innovation can spread through the population in a scenario where the groups' choices determine the social structure.

  20. Individual and Group Dynamics in Purchasing Activity

    CERN Document Server

    Gao, Lei; Fan, Chao; Liu, Xue-Jiao

    2010-01-01

    As a major part of the daily operation in an enterprise, purchasing frequency is of constant change. Recent approaches on the human dynamics can provide some new insights into the economic behaviors of companies in the supply chain. This paper captures the attributes of creation times of purchasing 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 plot. 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 t...

  1. The dynamics of group formation among leeches

    Directory of Open Access Journals (Sweden)

    Giacomo eBisson

    2012-05-01

    Full Text Available Leeches exploring a new environment continuously meet each other and merge in temporary groups. After 2-3 hours, leeches become attracted to each other eventually forming a large and stable group. When their number is reduced, leeches remain solitary, behaving independently. Group formation is facilitated by body injection of serotonin (5-HT and the level of endogenous 5-HT is elevated in leeches forming a large group. In contrast, intravenous injection of 5-HT antagonists prevented injected leeches from joining a large group of conspecifics. When sensilla near the head were ablated or the supraesophageal ganglion disconnected, leeches remained solitary, but explored the environment swimming and crawling. These results suggest that group formation is initiated by a release of 5-HT triggered by sensilla stimulation and its dynamics can be explained by the establishment of a reinforcement dynamics, as observed during human group formation. As 5-HT affects social interactions also in humans, group formation in leeches and humans share a similar dynamics and hormonal control.

  2. Kibel groups and their dynamic perspective

    DEFF Research Database (Denmark)

    Heinskou, Torben

    2010-01-01

    -therapists. Jack Nathan and Wil Pennycook-Graves Applying the Kanas Method on an acute ward. Ronan McIvor and Wil Pennycook-Graves Kibel groups and their dynamic perspective. Torben Heinskou Psychodynamic discussion groups on acute wards. Jonathan Radcliffe and Debora Diamond Using groups to provide containment...... and structure on an adolescent acute ward. Dylan Griffiths Moving groupwork into the day hospital setting. Isaura Manso Neto ABOUT THE EDITORS Jonathan Radcliffe, Katja Hajek, and Jerome Carson are Consultant Clinical Psychologists with the South London and Maudsley NHS Foundation Trust All have run groups...

  3. 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.

  4. How opinion dynamics generates group hierarchies

    CERN Document Server

    Gargiulo, F

    2010-01-01

    We recently proposed a model coupling the evolution of the opinions of the individual with the local network topology. The opinion dynamics is based on the Bounded Confidence model. The social networks is based on a group concept where each individual is totally connected to the members of its group and is linked to the individuals of the other groups with a given probability. During a time step, the individual has to decide between discussing with a member of its own network and applying the opinion dynamics, or moving groups because it has an opinion far from the average opinion of its own group. One of the main results we obtained is that the group sizes, starting from an homogeneous situation can be strongly heterogeneous at the equilibrium state. This kind of heterogeneity can be identified in many real networks. In this paper we present the complete set of behaviours that this complex model can exhibit, at group level. In particular we will focus on the mechanisms that lead to the stability of the group...

  5. 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.

  6. 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.

  7. Continuous Time Group Discovery in Dynamic Graphs

    Energy Technology Data Exchange (ETDEWEB)

    Miller, K; Eliassi-Rad, T

    2010-11-04

    With the rise in availability and importance of graphs and networks, it has become increasingly important to have good models to describe their behavior. While much work has focused on modeling static graphs, we focus on group discovery in dynamic graphs. We adapt a dynamic extension of Latent Dirichlet Allocation to this task and demonstrate good performance on two datasets. Modeling relational data has become increasingly important in recent years. Much work has focused on static graphs - that is fixed graphs at a single point in time. Here we focus on the problem of modeling dynamic (i.e. time-evolving) graphs. We propose a scalable Bayesian approach for community discovery in dynamic graphs. Our approach is based on extensions of Latent Dirichlet Allocation (LDA). LDA is a latent variable model for topic modeling in text corpora. It was extended to deal with topic changes in discrete time and later in continuous time. These models were referred to as the discrete Dynamic Topic Model (dDTM) and the continuous Dynamic Topic Model (cDTM), respectively. When adapting these models to graphs, we take our inspiration from LDA-G and SSN-LDA, applications of LDA to static graphs that have been shown to effectively factor out community structure to explain link patterns in graphs. In this paper, we demonstrate how to adapt and apply the cDTM to the task of finding communities in dynamic networks. We use link prediction to measure the quality of the discovered community structure and apply it to two different relational datasets - DBLP author-keyword and CAIDA autonomous systems relationships. We also discuss a parallel implementation of this approach using Hadoop. In Section 2, we review LDA and LDA-G. In Section 3, we review the cDTM and introduce cDTMG, its adaptation to modeling dynamic graphs. We discuss inference for the cDTM-G and details of our parallel implementation in Section 4 and present its performance on two datasets in Section 5 before concluding in

  8. 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.

  9. An Intergroup Perspective on Group Dynamics.

    Science.gov (United States)

    1983-10-01

    University Press, 1927. TaJfel , H. Experiments in Intergroup Discrimination . Scientific American, 1970, 223, 96-102. Te Selle, S. (Ed.). The Rediscovery...groups (Sherif & Sherif, 1969; Blake, Shepard, 6 Mouton, 1964; Tajfel , 1971; Billig, 1976). E. Leadership behavior. The behavior of group leaders and...are called institutional discrimination . (Thought question: how k 4 Page 53a La 0 (I0 00 z< 00 L4𔃻 I. -- C>. Pace 54 many 30 year old (age group too

  10. A dynamic policy for grouping maintenance activities

    NARCIS (Netherlands)

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

    1997-01-01

    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

  11. Creating A Group Harmonious And Dynamic Atmosphere In Jefc

    Institute of Scientific and Technical Information of China (English)

    蒋志俐

    2001-01-01

    With the rapid development of foreign language teaching, a group harmonious and dynamic atmosphere shows its importance in JEFC. It helps the students to learn English lieasantly and effectively and help the teachers to teach English easily and happily. It also helps to improve the teachers'teaching efficiently. However. the problem of the harmonious and dynamic atmosphere in class may result in anxiety among students. This paper aims at discussing the anxiety and the harmonious, dynamic atmosphere. It falls into three parts. The first part provides the analys is of the negative effects of anxiety in JEFC. The second introduces the positive effects of group harmonious,dynamic atmosphere in JEFC and the third discusses how to create the group harmonious, dynamic classroom atmosphere. This paper stresses the importance of the harmonious, dynamic atmosphere and introduce to use flexibly 5steps teaching way to create the harmonious and dynamic atmosphere.

  12. Hierarchical group dynamics in pigeon flocks.

    Science.gov (United States)

    Nagy, Máté; Akos, Zsuzsa; Biro, Dora; Vicsek, Tamás

    2010-04-08

    Animals that travel together in groups display a variety of fascinating motion patterns thought to be the result of delicate local interactions among group members. Although the most informative way of investigating and interpreting collective movement phenomena would be afforded by the collection of high-resolution spatiotemporal data from moving individuals, such data are scarce and are virtually non-existent for long-distance group motion within a natural setting because of the associated technological difficulties. Here we present results of experiments in which track logs of homing pigeons flying in flocks of up to 10 individuals have been obtained by high-resolution lightweight GPS devices and analysed using a variety of correlation functions inspired by approaches common in statistical physics. We find a well-defined hierarchy among flock members from data concerning leading roles in pairwise interactions, defined on the basis of characteristic delay times between birds' directional choices. The average spatial position of a pigeon within the flock strongly correlates with its place in the hierarchy, and birds respond more quickly to conspecifics perceived primarily through the left eye-both results revealing differential roles for birds that assume different positions with respect to flock-mates. From an evolutionary perspective, our results suggest that hierarchical organization of group flight may be more efficient than an egalitarian one, at least for those flock sizes that permit regular pairwise interactions among group members, during which leader-follower relationships are consistently manifested.

  13. Hierarchical group dynamics in pigeon flocks

    CERN Document Server

    Nagy, Mate; Biro, Dora; Vicsek, Tamas; 10.1038/nature08891

    2010-01-01

    Animals that travel together in groups display a variety of fascinating motion patterns thought to be the result of delicate local interactions among group members. Although the most informative way of investigating and interpreting collective movement phenomena would be afforded by the collection of high-resolution spatiotemporal data from moving individuals, such data are scarce and are virtually non-existent for long-distance group motion within a natural setting because of the associated technological difficulties. Here we present results of experiments in which track logs of homing pigeons flying in flocks of up to 10 individuals have been obtained by high-resolution lightweight GPS devices and analyzed using a variety of correlation functions inspired by approaches common in statistical physics. We find a well-defined hierarchy among flock members from data concerning leading roles in pairwise interactions, defined on the basis of characteristic delay times between birds' directional choices. The averag...

  14. Kibel groups and their dynamic perspective

    DEFF Research Database (Denmark)

    Heinskou, Torben

    2010-01-01

    wards into therapeutic communities? Leonard Fagin The relevance of the entire team to practicing groupwork on the ward. Bob Harris Acute wards: Context, pressures and satisfactions. Frank Holloway Reflections on the psychodynamics of an acute ward: Bion’s work in practice. Richard Duggins Containing...... 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......, the issues raised have a wider interest for those working to achieve excellent acute inpatient psychiatric settings in other countries. CONTENTS Part 1: Background and Principles What actually happens on acute wards? An observational study. Jonathan Radcliffe and Roger Smith Is it possible to make acute...

  15. Overlay Share Mesh for Interactive Group Communication with High Dynamic

    Institute of Scientific and Technical Information of China (English)

    WU Yan-hua; CAI Yun-ze; XU Xiao-ming

    2007-01-01

    An overlay share mesh infrastructure is presented for high dynamic group communication systems, such as distributed interactive simulation (DIS) and distributed virtual environments (DVE). Overlay share mesh infrastructure can own better adapting ability for high dynamic group than tradition multi-tree multicast infrastructure by sharing links among different groups. The mechanism of overlay share mesh based on area of interest (AOI) was discussed in detail in this paper. A large number of simulation experiments were done and the permance of mesh infrastructure was studied. Experiments results proved that overlay mesh infrastructure owns better adaptability than traditional multi-tree infrastructure for high dynamic group communication systems.

  16. 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.

  17. A conciliation mechanism for self-organizing dynamic small groups.

    Science.gov (United States)

    Ren, Minglun; Hu, Zhongfeng; Jain, Hemant

    2016-01-01

    A group of individuals, organizations or things in internet of things (IoT) often dynamically self-organizes in small groups to accomplish certain tasks. This is common in virtual organization, social networks and the evolving field of IoT. These small groups have different behavioral characteristics than large groups. Members individually have some requirements and contribute some resources to the group. The organization and operation of such a group requires dynamic identification of group requirements that can be fulfilled by available resources and is approved by the group. We apply design science methods to develop an artifact that helps in conciliation of collective requirements and resources of small groups while maintaining each member's satisfaction. The mechanism also supports dynamic conciliation as members leave and new members join the group. Each member's requirement is specified as an explicit/implicit objective that is feasible/not feasible based on resources available to the group and whether the requirement is in alignment with other members' objectives. We validate the artifact by using it for a manufacturing service group and simulating the change in collective group requirements and resources as group membership changes dynamically.

  18. 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.

  19. Group Dynamics and Willingness to Communicate in EFL Classrooms

    Institute of Scientific and Technical Information of China (English)

    MAI Xiao-ping

    2014-01-01

    This study explores how group dynamics (such as group cohesiveness and group norms) influence learners ’willingness to communicate (WTC) in an EFL classroom. The results from the 236 questionnaires showed that there was a significant correla-tion between group dynamics and WTC in an EFL classroom. A dozen students who participated in this study were interviewed for more in-depth information and the data revealed that most interviewees acknowledged the importance of the class group. The qualitative data also showed the importance of their own determination to learn in establishing their WTC.

  20. Group Dynamics in Janis's Theory of Groupthink: Backward and Forward.

    Science.gov (United States)

    McCauley

    1998-02-01

    Janis's groupthink theory is an appealing explanation of how group process can get in the way of optimal decision making. Unfortunately, Janis was selective and not always consistent in his application of research in group dynamics. This paper traces groupthink to its theoretical roots in order to suggest how a broader and more consistent use of research in group dynamics can advance understanding of decision-making problems. In particular, the paper explores and reinterprets the groupthink prediction that poor decision making is most likely when group cohesion is based on the personal attractiveness of group members. Copyright 1998 Academic Press.

  1. Metastable structures and size effects in small group dynamics

    OpenAIRE

    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 s...

  2. Metastable structures and size effects in small group dynamics

    OpenAIRE

    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 st...

  3. How experienced tutors facilitate tutorial dynamics in PBL groups.

    Science.gov (United States)

    Lee, Gin-Hong; Lin, Chaou-Shune; Lin, Yu-Hua

    2013-01-01

    Problem-based learning (PBL) tutorial are conducted in small groups, and successful learning in such groups requires good group facilitating skills. There is a lack of research on actual skills employed by tutors in facilitating the group dynamics. To explore the process of PBL tutorial small groups, focusing on the tutors' actual behavior in facilitating group dynamics. Eight experienced tutors from various departments in medical colleges participated in this research. Forty tutorial group sessions were videotaped. Among the 636 tutorial intervention episodes, 142 of them were associated with facilitating group dynamics. Tutors interventions as well as their recalls were transcribed verbatim. Qualitative research methods were utilized to analyze the data. There were 10 tutorial group dynamic situations and 48 tutorial skills. Analysis of the tutors' intentions employing these skills in the 10 situations showed that tutors were trying to achieve the following aims: (1) iteration of PBL principles, (2) delegation of responsibility to the students, (3) creation of a good discussion forum, and (4) the generation of a good learning atmosphere. Results from this study provide PBL tutors with a practical frame of reference on group dynamic facilitating skills and stimulate further research on this topic.

  4. Study Abroad: The Reality of Building Dynamic Group Learning.

    Science.gov (United States)

    Ransbury, Molly K.; Harris, Sandra A.

    1994-01-01

    The collaborative effort of a professor of human development with expertise in group process and a general education professor with expertise in Greek mythology and culture uses a case study format to apply theoretical models of group dynamics to the travel and learning experience of study abroad. Implications for course design and group process…

  5. Mean field theory for U(n) dynamical groups

    Energy Technology Data Exchange (ETDEWEB)

    Rosensteel, G, E-mail: george.rosensteel@tulane.edu [Department of Physics, Tulane University, New Orleans, LA 70118 (United States)

    2011-04-22

    Algebraic mean field theory (AMFT) is a many-body physics modeling tool which firstly, is a generalization of Hartree-Fock mean field theory, and secondly, an application of the orbit method from Lie representation theory. The AMFT ansatz is that the physical system enjoys a dynamical group, which may be either a strong or a weak dynamical Lie group G. When G is a strong dynamical group, the quantum states are, by definition, vectors in one irreducible unitary representation (irrep) space, and AMFT is equivalent to the Kirillov orbit method for deducing properties of a representation from a direct geometrical analysis of the associated integral co-adjoint orbit. AMFT can be the only tractable method for analyzing some complex many-body systems when the dimension of the irrep space of the strong dynamical group is very large or infinite. When G is a weak dynamical group, the quantum states are not vectors in one irrep space, but AMFT applies if the densities of the states lie on one non-integral co-adjoint orbit. The computational simplicity of AMFT is the same for both strong and weak dynamical groups. This paper formulates AMFT explicitly for unitary Lie algebras, and applies the general method to the Lipkin-Meshkov-Glick su(2) model and the Elliott su(3) model. When the energy in the su(3) theory is a rotational scalar function, Marsden-Weinstein reduction simplifies AMFT dynamics to a two-dimensional phase space.

  6. Three applications of functional analysis with group dynamic cognitive behavioral group therapy.

    Science.gov (United States)

    Scharwächter, Peter

    2008-01-01

    Case illustrations from group dynamic cognitive behavioral group therapy are presented to demonstrate three applications of functional analysis and the resulting cognitive behavioral interventions. The principles of group dynamic cognitive behavioral group therapy are explained. A functional analysis is applied first to the problem behavior of an individual group member. A clinical case illustrates how the group members help to change this individual group member's behavior from a learning theory perspective. Next, the circular interactional problem behavior between two group members is reduced to the individual functional analysis of each of the two member's problem behaviors. It is then illustrated how the two group member's problem behaviors, as well as feedback from others, contribute toward helping to change each others behavior. The paper concludes that functional analysis and ensuing behavioral interventions can be also applied to group as a whole behavior.

  7. Skupinska dinamika negovalnega tima: Group dynamics of nursing team:

    OpenAIRE

    Škerbinek, Ladi

    1998-01-01

    The article defines the most important psychodynamic elements of the group respectively nursing team. The satisfaction of nurses and nursing technicians with their work does not depend solely onthe work itself but to a grat extent also on the team he/she belongs to. The article describes the group and interpersonal relations in it, group dynamics and devlopmental process of the group, respectively team, basic characteristics of team behaviour and leadership. V prispevku so opredeljeni najp...

  8. 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.

  9. 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.

  10. 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.

  11. Dynamic Task Performance, Cohesion, and Communications in Human Groups.

    Science.gov (United States)

    Giraldo, Luis Felipe; Passino, Kevin M

    2016-10-01

    In the study of the behavior of human groups, it has been observed that there is a strong interaction between the cohesiveness of the group, its performance when the group has to solve a task, and the patterns of communication between the members of the group. Developing mathematical and computational tools for the analysis and design of task-solving groups that are not only cohesive but also perform well is of importance in social sciences, organizational management, and engineering. In this paper, we model a human group as a dynamical system whose behavior is driven by a task optimization process and the interaction between subsystems that represent the members of the group interconnected according to a given communication network. These interactions are described as attractions and repulsions among members. We show that the dynamics characterized by the proposed mathematical model are qualitatively consistent with those observed in real-human groups, where the key aspect is that the attraction patterns in the group and the commitment to solve the task are not static but change over time. Through a theoretical analysis of the system we provide conditions on the parameters that allow the group to have cohesive behaviors, and Monte Carlo simulations are used to study group dynamics for different sets of parameters, communication topologies, and tasks to solve.

  12. 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.

  13. 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

  14. 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…

  15. 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…

  16. The Dynamics of Access to Groups in Working Memory

    Science.gov (United States)

    Farrell, Simon; Lelievre, Anna

    2012-01-01

    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…

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

    Science.gov (United States)

    Liu, Hongwei; Ma, Haiqiang; Wei, Kejin; Yang, Xiuqing; Qu, Wenxiu; Dou, Tianqi; Chen, Yitian; Li, Ruixue; Zhu, Wu

    2016-07-01

    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.

  18. Dynamics of social positioning patterns in group-robot interactions

    OpenAIRE

    Vroon, Jered; Joosse, Michiel; Lohse, Manja; Kolkmeier, Jan; Kim, Jaebok; Truong, Khiet; Englebienne, Gwenn; Heylen, Dirk; Evers, Vanessa

    2015-01-01

    When a mobile robot interacts with a group of people, it has to consider its position and orientation. We introduce a novel study aimed at generating hypotheses on suitable behavior for such social positioning, explicitly focusing on interaction with small groups of users and allowing for the temporal and social dynamics inherent in most interactions. In particular, the interactions we look at are approach, converse and retreat. In this study, groups of three participants and a telepresence r...

  19. Mean field theory for U(n) dynamical groups

    Science.gov (United States)

    Rosensteel, G.

    2011-04-01

    Algebraic mean field theory (AMFT) is a many-body physics modeling tool which firstly, is a generalization of Hartree-Fock mean field theory, and secondly, an application of the orbit method from Lie representation theory. The AMFT ansatz is that the physical system enjoys a dynamical group, which may be either a strong or a weak dynamical Lie group G. When G is a strong dynamical group, the quantum states are, by definition, vectors in one irreducible unitary representation (irrep) space, and AMFT is equivalent to the Kirillov orbit method for deducing properties of a representation from a direct geometrical analysis of the associated integral co-adjoint orbit. AMFT can be the only tractable method for analyzing some complex many-body systems when the dimension of the irrep space of the strong dynamical group is very large or infinite. When G is a weak dynamical group, the quantum states are not vectors in one irrep space, but AMFT applies if the densities of the states lie on one non-integral co-adjoint orbit. The computational simplicity of AMFT is the same for both strong and weak dynamical groups. This paper formulates AMFT explicitly for unitary Lie algebras, and applies the general method to the Lipkin-Meshkov-Glick {\\mathfrak s}{\\mathfrak u} (2) model and the Elliott {\\mathfrak s}{\\mathfrak u} (3) model. When the energy in the {\\mathfrak s}{\\mathfrak u} (3) theory is a rotational scalar function, Marsden-Weinstein reduction simplifies AMFT dynamics to a two-dimensional phase space.

  20. 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.

  1. 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.

  2. Evolutionary dynamics of group interactions on structured populations: A review

    CERN Document Server

    Perc, Matjaz; Szolnoki, Attila; Floría, Luis M; Moreno, Yamir; 10.1098/rsif.2012.0997

    2013-01-01

    Interactions among living organisms, from bacteria colonies to human societies, are inherently more complex than interactions among particles and nonliving matter. Group interactions are a particularly important and widespread class, representative of which is the public goods game. In addition, methods of statistical physics have proven valuable for studying pattern formation, equilibrium selection, and self-organisation in evolutionary games. Here we review recent advances in the study of evolutionary dynamics of group interactions on structured populations, including lattices, complex networks and coevolutionary models. We also compare these results with those obtained on well-mixed populations. The review particularly highlights that the study of the dynamics of group interactions, like several other important equilibrium and non-equilibrium dynamical processes in biological, economical and social sciences, benefits from the synergy between statistical physics, network science and evolutionary game theory...

  3. Dynamical real space renormalization group applied to sandpile models.

    Science.gov (United States)

    Ivashkevich, E V; Povolotsky, A M; Vespignani, A; Zapperi, S

    1999-08-01

    A general framework for the renormalization group analysis of self-organized critical sandpile models is formulated. The usual real space renormalization scheme for lattice models when applied to nonequilibrium dynamical models must be supplemented by feedback relations coming from the stationarity conditions. On the basis of these ideas the dynamically driven renormalization group is applied to describe the boundary and bulk critical behavior of sandpile models. A detailed description of the branching nature of sandpile avalanches is given in terms of the generating functions of the underlying branching process.

  4. Deriving a group psychic apparatus and a typology of group mental states from Bion's group dynamics

    OpenAIRE

    2009-01-01

    There is abundant psychoanalytically-oriented literature which apply Freud's concepts related to his psychic apparatus theory. For instance, many researchers often describe group phenomena in terms of "conscious", "unconscious", "ego", and "superego". However, with the exception of Rene Kas's pioneer work, l'appareil psychic groupal, there is, to the author's knowledge, no study which has discussed explicitly and systematically the group's psychic apparatus. In the present paper the author ha...

  5. New insights in particle dynamics from group cohomology

    CERN Document Server

    Aldaya, V; 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)

  6. The dynamical state of galaxy groups and their luminosity content

    CERN Document Server

    Martinez, Hector J

    2011-01-01

    We analyse the dependence of the luminosity function of galaxies in groups (LF) on group dynamical state. We use the Gaussianity of the velocity distribution of galaxy members as a measurement of the dynamical equilibrium of groups identified in the SDSS Data Release 7 by Zandivarez & Martinez. We apply the Anderson-Darling goodness-of-fit test to distinguish between groups according to whether they have Gaussian or Non-Gaussian velocity distributions, i.e., whether they are relaxed or not. For these two subsamples, we compute the $^{0.1}r-$band LF as a function of group virial mass and group total luminosity. For massive groups, ${\\mathcal M}>5 \\times 10^{13} \\ M_{\\odot} \\ h^{-1}$, we find statistically significant differences between the LF of the two subsamples: the LF of groups that have Gaussian velocity distributions have a brighter characteristic absolute magnitude ($\\sim0.3$ mag) and a steeper faint end slope ($\\sim0.25$). We detect a similar effect when comparing the LF of bright ($M^{group}_{^{0...

  7. Multi-modal analysis of small-group conversational dynamics

    NARCIS (Netherlands)

    Akker, op den Rieks; Gatica-Perez, Daniel; Heylen, Dirk; Renals, Steve; Bourlard, Hervé; Carletta, Jean; Popescu-Belis, Andrei

    2012-01-01

    This chapter provides an overview of the basic problems realted to automatic understanding of conversational group dynamics. It provides an overview of current research in automatic detection of the addressee(s) of the speaker in multiparty conversations, the visual focus of attention of participant

  8. Coherent States, Dynamics and Semiclassical Limit on Quantum Groups

    CERN Document Server

    Aref'eva, I Ya; Viswanathan, K S; Volovich, I V

    1994-01-01

    Coherent states on the quantum group $SU_q(2)$ are defined by using harmonic analysis and representation theory of the algebra of functions on the quantum group. Semiclassical limit $q\\rightarrow 1$ is discussed and the crucial role of special states on the quantum algebra in an investigation of the semiclassical limit is emphasized. An approach to $q$-deformation as a $q$-Weyl quantization and a relavence of contact geometry in this context is pointed out. Dynamics on the quantum group parametrized by a real time variable and corresponding to classical rotations is considered.

  9. HSTPROMO and the Dynamics of the Local Group

    Science.gov (United States)

    Besla, Gurtina

    2016-05-01

    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. I will provide an overview of key contributions by the Hubble Space Telescope to this evolving picture. In particular, I will highlight the HSTPROMO team’s proper motion measurements of key players in the Local Group, such as the fastest (Leo I) and most massive (LMC and SMC) satellites of the Milky Way and the first ever direct proper motion measurement of M31. These results have met with controversy, challenging preconceived notions of the orbital dynamics of key components of the Local Group. I will further highlight the importance of HST’s continued role in this field in the era of Gaia.

  10. 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.

  11. Modelling animal group fission using social network dynamics.

    Science.gov (United States)

    Sueur, Cédric; Maire, Anaïs

    2014-01-01

    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.

  12. Dynamical renormalization group resummation of finite temperature infrared divergences

    CERN Document Server

    Boyanovsky, D; 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 applied 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 $e^{-\\alpha T t \\ln[t/t_0]}$ which prevents a quasiparticle interpretation of charged collective excitations at finite temperature. 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 trascends the conceptual limitations of the quasiparticle picture and other type of resummation schemes. We derive a simple criterion for establishing the validity of the quasiparticle picture to lowest order.

  13. A dynamic,secure,and efficient group key agreement protocol

    Institute of Scientific and Technical Information of China (English)

    ZHENG Shihui; WANG Shaohui; ZHANG Guoyan

    2007-01-01

    The key challenge of dynamic peer communication is how to realize secure and efficient group key management.A two rounds key agreement protocol for dynamic peer group (DPG) is proposed in this paper.The protocol,which was obtained by combining the E1Gamal encryption scheme with the E1Gamal signature scheme,is efficient and simple.The protocol is proven secure against passive attack by using indistinguishable method.Moreover,both perfect forward secrecy (PFS) and key independence (KI) were achieved.Because the protocol is based on the broadcast channel,it is also suitable for key agreement in wireless communications,especially in ad-hoc networks.

  14. Collective Attention and the Dynamics of Group Deals

    CERN Document Server

    Ye, Mao; Aperjis, Christina; Huberman, Bernardo A; Sandholm, Thomas

    2011-01-01

    We present a study of the group purchasing behavior of daily deal customers. Our goal is to understand the dynamics of purchases to ultimately be able to predict how successful a deal will be. We propose a general dynamic model of collective attention for group buying behavior. In our model, the aggregate number of purchases at a given time comprises two types of processes: random discovery and social propagation. We find that these processes are very clearly separated by an inflection point, which in Groupon typically coincides with the tipping time, the time after which there are enough purchases to guarantee deal transactions. Using data from Groupon we empirically verify our theoretically inferred purchase growth models.

  15. Fractal groups: Emergent dynamics in on-line learning communities

    Directory of Open Access Journals (Sweden)

    Junia de Carvalho Fidelis Braga

    Full Text Available Drawing on complexity theory, this work discusses the complex dynamics and emergent patterns of on-line learning communities based on a doctoral study in the area of Applied Linguistics. The analysis will center on the interlocutions of fifty students who interacted in small groups without the teacher's direct intervention, in an undergraduate course offered by the School of Languages and Literature at the Federal University of Minas Gerais. By analyzing the data, I demonstrate that out of the interactions among the peers of autonomous on-line learning communities arise opportunities for the construction of shared meaning, distributed leadership, as well as other dynamics. I also demonstrate the fractal nature of these communities. Moreover, I discuss how these findings shed light on the creation and development of course designs for large groups.

  16. Group impressions as dynamic configurations: the tensor product model of group impression formation and change.

    Science.gov (United States)

    Kashima, Y; Woolcock, J; Kashima, E S

    2000-10-01

    Group impressions are dynamic configurations. The tensor product model (TPM), a connectionist model of memory and learning, is used to describe the process of group impression formation and change, emphasizing the structured and contextualized nature of group impressions and the dynamic evolution of group impressions over time. TPM is first shown to be consistent with algebraic models of social judgment (the weighted averaging model; N. Anderson, 1981) and exemplar-based social category learning (the context model; E. R. Smith & M. A. Zárate, 1992), providing a theoretical reduction of the algebraic models to the present connectionist framework. TPM is then shown to describe a common process that underlies both formation and change of group impressions despite the often-made assumption that they constitute different psychological processes. In particular, various time-dependent properties of both group impression formation (e.g., time variability, response dependency, and order effects in impression judgments) and change (e.g., stereotype change and group accentuation) are explained, demonstrating a hidden unity beneath the diverse array of empirical findings. Implications of the model for conceptualizing stereotype formation and change are discussed.

  17. Lie group analysis for multi-scale plasma dynamics

    CERN Document Server

    Kovalev, Vladimir F

    2011-01-01

    An application of approximate transformation groups to study dynamics of a system with distinct time scales is discussed. The utilization of the Krylov-Bogoliubov-Mitropolsky method of averaging to find solutions of the Lie equations is considered. Physical illustrations from the plasma kinetic theory demonstrate the potentialities of the suggested approach. Several examples of invariant solutions for the system of the Vlasov-Maxwell equations for the two-component (electron-ion) plasma are presented.

  18. Internal character dictates transition dynamics between isolation and cohesive grouping

    Science.gov (United States)

    Manrique, Pedro D.; Hui, Pak Ming; Johnson, Neil F.

    2015-12-01

    We show that accounting for internal character among interacting heterogeneous entities generates rich transition behavior between isolation and cohesive dynamical grouping. Our analytical and numerical calculations reveal different critical points arising for different character-dependent grouping mechanisms. These critical points move in opposite directions as the population's diversity decreases. Our analytical theory may help explain why a particular class of universality is so common in the real world, despite the fundamental differences in the underlying entities. It also correctly predicts the nonmonotonic temporal variation in connectivity observed recently in one such system.

  19. Collective Attention and the Dynamics of Group Deals

    OpenAIRE

    Ye, Mao; Wang, Chunyan; Aperjis, Christina; Huberman, Bernardo A.; Sandholm, Thomas

    2011-01-01

    We present a study of the group purchasing behavior of daily deals in Groupon and LivingSocial and introduce a predictive dynamic model of collective attention for group buying behavior. In our model, the aggregate number of purchases at a given time comprises two types of processes: random discovery and social propagation. We find that these processes are very clearly separated by an inflection point. Using large data sets from both Groupon and LivingSocial we show how the model is able to p...

  20. 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.

  1. Approximate group context tree: applications to dynamic programming and dynamic choice models

    CERN Document Server

    Belloni, Alexandre

    2011-01-01

    The paper considers a variable length Markov chain model associated with a group of stationary processes that share the same context tree but potentially different conditional probabilities. We propose a new model selection and estimation method, develop oracle inequalities and model selection properties for the estimator. These results also provide conditions under which the use of the group structure can lead to improvements in the overall estimation. Our work is also motivated by two methodological applications: discrete stochastic dynamic programming and dynamic discrete choice models. We analyze the uniform estimation of the value function for dynamic programming and the uniform estimation of average dynamic marginal effects for dynamic discrete choice models accounting for possible imperfect model selection. We also derive the typical behavior of our estimator when applied to polynomially $\\beta$-mixing stochastic processes. For parametric models, we derive uniform rate of convergence for the estimation...

  2. Strategy selection in evolutionary game dynamics on group interaction networks.

    Science.gov (United States)

    Tan, Shaolin; Feng, Shasha; Wang, Pei; Chen, Yao

    2014-11-01

    Evolutionary game theory provides an appropriate tool for investigating the competition and diffusion of behavioral traits in biological or social populations. A core challenge in evolutionary game theory is the strategy selection problem: Given two strategies, which one is favored by the population? Recent studies suggest that the answer depends not only on the payoff functions of strategies but also on the interaction structure of the population. Group interactions are one of the fundamental interactive modes within populations. This work aims to investigate the strategy selection problem in evolutionary game dynamics on group interaction networks. In detail, the strategy selection conditions are obtained for some typical networks with group interactions. Furthermore, the obtained conditions are applied to investigate selection between cooperation and defection in populations. The conditions for evolution of cooperation are derived for both the public goods game and volunteer's dilemma game. Numerical experiments validate the above analytical results.

  3. 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.

  4. Opinion dynamics on a group structured adaptive network

    CERN Document Server

    Gargiulo, F

    2009-01-01

    Many models have been proposed to analyze the evolution of opinion structure due to the interaction of individuals in their social environment. Such models analyze the spreading of ideas both in completely interacting backgrounds and on social networks, where each person has a finite set of interlocutors.Moreover also the investigation on the topological structure of social networks has been object of several analysis, both from the theoretical and the empirical point of view. In this framework a particularly important area of study regards the community structure inside social networks.In this paper we analyze the reciprocal feedback between the opinions of the individuals and the structure of the interpersonal relationships at the level of community structures. For this purpose we define a group based random network and we study how this structure co-evolve with opinion dynamics processes. We observe that the adaptive network structure affects the opinion dynamics process helping the consensus formation. Th...

  5. Dynamics of Microbial Functional Groups in Rhizosphere of Spring Barley

    Directory of Open Access Journals (Sweden)

    Vlad Stoian

    2016-11-01

    Full Text Available Plant rhizosphere is the portion of soil which is in direct contact with the plant roots. From the microbiological point of view, this area is characterized by strong dynamic of functional groups with high specificity towards the substrate available. Spring barley is a crop with high requirements to the composition of the microflora in the rhizosphere, disturbances produced by agronomic inputs affecting the stability of rhizospheric contact interfaces and ultimately the plant growth. Analysis of changes within the microbial community was carried out with the purpose of defining the disruptive impact of mineral inputs and potential of zeolite to reduce these disruptions. Microbial functional groups were analyzed on the basis of the CO2 export under the specific conditions of soil inoculation on specific substrates over a time period of incubation. Microresp detection plates allow evaluation of a large number of samples under identical conditions of inoculation and the establishment of dynamics of the entire microbial community. The dynamics of the entire microbial communities (basal respiration is stimulated to increase in case of unilateral application of zeolite and zeolite as a buffer for urea fertilization. General growth trend of microbial communities follows proportional the associated application of zeolite with urea, the most powerful non-symbiotic nitrogen fixation processes being stimulated by this combination of fertilizers. Simultaneously, an increase in the dynamics of denitrifiers was observed, also the decomposition of lignin and cellulose and biological crust formation due to the proliferation of cyanobacteria. Rhizosphere of barley plants is characterized by the presence of actinomycetes as dominant in functional microbial community of all experimental variants analyzed with a high capacity for biological degradation and raised mineralization of organic matter.

  6. 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.

  7. Dynamic regulation of Polycomb group activity during plant development.

    Science.gov (United States)

    Bemer, Marian; Grossniklaus, Ueli

    2012-11-01

    Polycomb group (PcG) complexes play important roles in phase transitions and cell fate determination in plants and animals, by epigenetically repressing sets of genes that promote either proliferation or differentiation. The continuous differentiation of new organs in plants, such as leaves or flowers, requires a highly dynamic PcG function, which can be induced, modulated, or repressed when necessary. In this review, we discuss the recent advance in understanding PcG function in plants and focus on the diverse molecular mechanisms that have been described to regulate and counteract PcG activity in Arabidopsis.

  8. 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....... This problem is not only found at Aalborg University but also at the engineering colleges in Denmark. For that reason a course was developed with the aim of addressing the problem and showing, how it can be dealt with. So far the course has been offered several times to supervisors at the engineering colleges...

  9. Robustness and Vulnerability of Networks with Dynamical Dependency Groups

    Science.gov (United States)

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

    2016-11-01

    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. Far from random: dynamical groupings among the NEO population

    Science.gov (United States)

    de la Fuente Marcos, C.; de la Fuente Marcos, R.

    2016-03-01

    Among the near-Earth object (NEO) population, there are comets and active asteroids which are sources of fragments that initially move together; in addition, some NEOs follow orbits temporarily trapped in a web of secular resonances. These facts contribute to increasing the risk of meteoroid strikes on Earth, making its proper quantification difficult. The identification and subsequent study of groups of small NEOs that appear to move in similar trajectories are necessary steps in improving our understanding of the impact risk associated with meteoroids. Here, we present results of a search for statistically significant dynamical groupings among the NEO population. Our Monte Carlo-based methodology recovers well-documented groupings like the Taurid Complex or the one resulting from the split comet 73P/Schwassmann-Wachmann 3, and new ones that may have been the source of past impacts. Among the most conspicuous are the Mjolnir and Ptah groups, perhaps the source of recent impact events like Almahata Sitta and Chelyabinsk, respectively. Meteoroid 2014 AA, that hit the Earth on 2014 January 2, could have its origin in a marginally significant grouping associated with Bennu. We find that most of the substructure present within the orbital domain of the NEOs is of resonant nature, probably induced by secular resonances and the Kozai mechanism that confine these objects into specific paths with well-defined perihelia.

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

    Energy Technology Data Exchange (ETDEWEB)

    Bresson, Emmanuel; Chevassut, Olivier; Pointcheval, David

    2002-02-14

    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.

  12. Beyond 'vulnerable groups': contexts and dynamics of vulnerability.

    Science.gov (United States)

    Zarowsky, Christina; Haddad, Slim; Nguyen, Vinh-Kim

    2013-03-01

    This paper reviews approaches to vulnerability in public health, introducing a series of 10 papers addressing vulnerability in health in Africa. We understand vulnerability as simultaneously a condition and a process. Social inequalities are manifest in and exacerbate three key dimensions of vulnerability: the initial level of wellbeing, the degree of exposure to risk, and the capacity to manage risk effectively. We stress the dynamic interactions linking material and social deprivation, poverty, powerlessness and ill health: risks or shocks and their health impacts are intimately interconnected and reinforce each other in a cycle which in the absence of effective interventions, increases vulnerability. An inductive process which does not begin with an a priori definition or measurement of 'vulnerability' and which does not assume the existence of fixed 'vulnerable groups' allowed us both to re-affirm core aspects of existing conceptual frameworks, and to engage in new ways with literature specifically addressing vulnerability and resilience at the population level as well as with literature - for example in ecology, and on the concept of frailty in research on aging - with which researchers on health and poverty in Africa may not be familiar. We invite conceptual and empirical work on vulnerability in complex systems frameworks. These perspectives emphasize contexts and nonlinear causality thus supporting analyses of vulnerability and resilience as both markers and emergent properties of dynamic interactions. We accept a working definition of vulnerability, and recognize that some definable groups of people are more likely than others to suffer harm from exposure to health risks. But we suggest that the real work - at both intellectual and policy/political levels - lies in understanding and responding to the dynamics, meanings and power relations underlying actual instances and processes of vulnerability and harm.

  13. Far from random: dynamical groupings among the NEO population

    CERN Document Server

    Marcos, C de la Fuente

    2016-01-01

    Among the near-Earth object (NEO) population there are comets and active asteroids which are sources of fragments that initially move together; in addition, some NEOs follow orbits temporarily trapped in a web of secular resonances. These facts contribute to increasing the risk of meteoroid strikes on Earth, making its proper quantification difficult. The identification and subsequent study of groups of small NEOs that appear to move in similar trajectories are necessary steps in improving our understanding of the impact risk associated with meteoroids. Here, we present results of a search for statistically significant dynamical groupings among the NEO population. Our Monte Carlo-based methodology recovers well-documented groupings like the Taurid Complex or the one resulting from the split comet 73P/Schwassmann-Wachmann 3, and new ones that may have been the source of past impacts. Among the most conspicuous are the Mjolnir and Ptah groups, perhaps the source of recent impact events like Almahata Sitta and C...

  14. Dynamical segregation of galaxies in groups and clusters

    CERN Document Server

    Lares, M; Sánchez, A G

    2004-01-01

    We have performed a systematic analysis of the dynamics of different galaxy populations in galaxy groups from the 2dFGRS. For this purpose we have combined all the groups into a single system, where velocities v and radius r are expressed adimensionally. We have used several methods to compare the distributions of relative velocities of galaxies with respect to the group centre for samples selected according to their spectral type (as defined by Madgwick et al., 2002), bj band luminosity and B-R colour index. We have found strong segregation effects: spectral type I objects show a statistically narrower velocity distribution than that of galaxies with a substantial star formation activity (type II-IV). Similarly, the same behavior is observed for galaxies with colour index B-R>1 compared to galaxies with B-R-19) galaxies show the same segregation. It is not important once the sample is restricted to a given spectral type. These effects are particularly important in the central region (Rp

  15. 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

    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 o

  16. 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...

  17. Group dynamic behavior and psychometric profiles as substantial driver for pedestrian dynamics

    CERN Document Server

    Schultz, Michael; Fricke, Hartmut; Schlag, Bernhard

    2012-01-01

    Our current research lays emphasis on the extended pedestrian perception and copes with both the dynamic group behavior and the individual evaluation of situations, and hence, rather focuses on the tactical level of movement behavior. Whereas common movement models primary consider operational aspects (spatial exclusion or distance and direction related repulsion), the consideration of psychophysical concepts and intra-group coordination overcomes the idea of directed repulsion forces and derives specific movement decision with respect to the individual evaluation of situations. To provide a solid basis we analyze both data recorded at a mass event and data from a double-staged evacuation test to derive essential group dynamic behaviors and psychological related decision principles, respectively.

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

    Energy Technology Data Exchange (ETDEWEB)

    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. (Office of Energy Research, Office of Basic Energy Sciences, Materials Sciences Division, U.S. Department of Energy (United States))

    1999-04-01

    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 acclerators. (AIP) [copyright] [ital 1999] [ital American Institute of Physics

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

    Science.gov (United States)

    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.

    1999-04-01

    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 acclerators. (AIP)

  20. Citing Dynamic Data - Research Data Alliance working group recommendations

    Science.gov (United States)

    Asmi, Ari; Rauber, Andreas; Pröll, Stefan; van Uytvanck, Dieter

    2016-04-01

    Geosciences research data sets are typically dynamic: changing over time as new records are added, errors are corrected and obsolete records are deleted from the data sets. Researchers often use only parts of the data sets or data stream, creating specific subsets tailored to their experiments. In order to keep such experiments reproducible and to share and cite the particular data used in a study, researchers need means of identifying the exact version of a subset as it was used during a specific execution of a workflow, even if the data source is continuously evolving. Some geosciences data services have tried to approach this problem by creating static versions of their data sets, and some have simply ignored this issue. The RDA Working Group on Dynamic Data Citation (WGDC) has instead approached the issue with a set of recommendations based upon versioned data, timestamping and a query based subsetting mechanism. The 14 RDA WGDC recommendations on how to adapt a data source for providing identifiable subsets for the long term are: Preparing the Data and the Query Store R1 - Data Versioning R2 - Timestamping R3 - Query Store Facilities Persistently Identifying Specific Data Sets R4 - Query Uniqueness R5 - Stable Sorting R6 - Result Set Verification R7 - Query Timestamping R8 - Query PID R9 - Store the Query R10 - Automated Citation Texts Resolving PIDs and Retrieving the Data - R11 - Landing Page R12 - Machine Actionability Upon modifications to the Data Infrastructure R13 - Technology Migration R14 - Migration Verification We present a detailed discussion of the recommendations, the rationale behind them, and give examples of how to implement them.

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

    NARCIS (Netherlands)

    Walter, F.; Bruch, H.

    2008-01-01

    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 qualit

  2. 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

  3. 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.

  4. 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.

  5. Dynamics of two-group conflicts: A statistical physics model

    Science.gov (United States)

    Diep, H. T.; Kaufman, Miron; Kaufman, Sanda

    2017-03-01

    We propose a "social physics" model for two-group conflict. We consider two disputing groups. Each individual i in each of the two groups has a preference si regarding the way in which the conflict should be resolved. The individual preferences span a range between + M (prone to protracted conflict) and - M (prone to settle the conflict). The noise in this system is quantified by a "social temperature". Individuals interact within their group and with individuals of the other group. A pair of individuals (i , j) within a group contributes -si ∗sj to the energy. The inter-group energy of individual i is taken to be proportional to the product between si and the mean value of the preferences from the other group's members. We consider an equivalent-neighbor Renyi-Erdos network where everyone interacts with everyone. We present some examples of conflicts that may be described with this model.

  6. 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…

  7. Verbal Synchrony and Action Dynamics in Large Groups.

    Science.gov (United States)

    von Zimmermann, Jorina; Richardson, Daniel C

    2016-01-01

    While synchronized movement has been shown to increase liking and feelings of togetherness between people, we investigated whether collective speaking in time would change the way that larger groups played a video game together. Anthropologists have speculated that the function of interpersonal coordination in dance, chants, and singing is not just to produce warm, affiliative feelings, but also to improve group action. The group that chants and dances together hunts well together. Direct evidence for this is sparse, as research so far has mainly studied pairs, the effects of coordinated physical movement, and measured cooperation and affiliative decisions. In our experiment, large groups of people were given response handsets to play a computer game together, in which only joint coordinative efforts lead to success. Before playing, the synchrony of their verbal behavior was manipulated. After the game, we measured group members' affiliation toward their group, their performance on a memory task, and the way in which they played the group action task. We found that verbal synchrony in large groups produced affiliation, enhanced memory performance, and increased group members' coordinative efforts. Our evidence suggests that the effects of synchrony are stable across modalities, can be generalized to larger groups and have consequences for action coordination.

  8. 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...

  9. Dynamics of students’ epistemological framing in group problem solving

    Science.gov (United States)

    Nguyen, Hai D.; Chari, Deepa N.; Sayre, Eleanor C.

    2016-11-01

    Many studies have investigated students’ epistemological framing when solving physics problems. Framing supports students’ problem solving as they decide what knowledge to employ and the necessary steps to solve the problem. Students may frame the same problem differently and take alternative paths to a correct solution. When students work in group settings, they share and discuss their framing to decide how to proceed in problem solving as a whole group. In this study, we investigate how groups of students negotiate their framing and frame shifts in group problem solving.

  10. Dynamics of students' epistemological framing in group problem solving

    CERN Document Server

    Nguyen, Hai D; Sayre, Eleanor C

    2016-01-01

    Many studies have investigated students' epistemological framing when solving physics problems. Framing supports students' problem solving as they decide what knowledge to employ and the necessary steps to solve the problem. Students may frame the same problem differently and take alternate paths to a correct solution. When students work in group settings, they share and discuss their framing to decide how to proceed in problem solving as a whole group. In this study, we investigate how groups of students negotiate their framing and frame shifts in group problem solving.

  11. Hybrid dynamics in a species group of swallowtail butterflies.

    Science.gov (United States)

    Dupuis, J R; Sperling, F A H

    2016-10-01

    Hybrid zones provide unique natural laboratories for studying mechanisms of evolution. But identification and classification of hybrid individuals (F1, F2, backcross, etc.) can be complicated by real population changes over time as well as by use of different marker types, both of which challenge documentation of hybrid dynamics. Here, we use multiple genetic markers (mitochondrial DNA, microsatellites and genomewide single nucleotide polymorphisms) to re-examine population structure in a hybrid zone between two species of swallowtail butterflies in western Canada, Papilio machaon and P. zelicaon. Our aim was to test whether their hybrid dynamics remain the same as found 30 years ago using morphology and allozymes, and we compared different genetic data sets as well as alternative hybrid identification and classification methods. Overall, we found high differentiation between the two parental species, corroborating previous research from the 1980s. We identified fewer hybrid individuals in the main zone of hybridization in recent years, but this finding depended on the genetic markers considered. Comparison of methods with simulated data sets generated from our data showed that single nucleotide polymorphisms were more powerful than microsatellites for both hybrid identification and classification. Moreover, substantial variation among comparisons underlined the value of multiple markers and methods for documenting evolutionarily dynamic systems.

  12. Dwarf galaxies in the dynamically evolved NGC 1407 Group

    Science.gov (United States)

    Trentham, Neil; Tully, R. Brent; Mahdavi, Andisheh

    2006-07-01

    The NGC 1407 Group stands out among nearby structures by its properties that suggest it is massive and evolved. It shares properties with entities that have been called fossil groups: the 1.4m differential between the dominant elliptical galaxy and the second brightest galaxy comes close to satisfying the definition that has been used to define the fossil class. There are few intermediate-luminosity galaxies, but a large number of dwarfs in the group. We estimate there are 250 group members to the depth of our survey. The slope of the faint end of the luminosity function (reaching MR = -12) is α = -1.35. Velocities for 35 galaxies demonstrate that this group with one dominant galaxy has a mass of 7 × 1013Msolar and M/LR = 340Msolar/Lsolar. Two galaxies in close proximity to NGC 1407 have very large blueshifts. The most notable is the second brightest galaxy, NGC 1400, with a velocity of -1072 km s-1 with respect to the group mean. We report the detection of X-ray emission from this galaxy and from the group.

  13. Dwarf galaxies in the Dynamically Evolved NGC 1407 Group

    CERN Document Server

    Trentham, N; Tully, R B; Mahdavi, Andisheh; Trentham, Neil

    2006-01-01

    The NGC 1407 Group stands out among nearby structures by its properties that suggest it is massive and evolved. It shares properties with entities that have been called fossil groups: the 1.4 magnitude differential between the dominant elliptical galaxy and the second brightest galaxy comes close to satisfying the definition that has been used to define the fossil class. There are few intermediate luminosity galaxies, but a large number of dwarfs in the group. We estimate there are 250 group members to the depth of our survey. The slope of the faint end of the luminosity function (reaching M_R = -12) is alpha = -1.35. Velocities for 35 galaxies demonstrate that this group with one dominant galaxy has a mass of 7 X 10^13 M_sun and M/L_R = 340. Two galaxies in close proximity to NGC 1407 have very large blueshifts. The most notable is the second brightest galaxy, NGC 1400, with a velocity of -1072 km/s with respect to the group mean. We report the detection of X-ray emission from this galaxy and from the group.

  14. Mountain gorilla ranging patterns: influence of group size and group dynamics.

    Science.gov (United States)

    Caillaud, Damien; Ndagijimana, Felix; Giarrusso, Anthony J; Vecellio, Veronica; Stoinski, Tara S

    2014-08-01

    Since the 1980s, the Virunga mountain gorilla population has almost doubled, now reaching 480 individuals living in a 430-km(2) protected area. Analysis of the gorillas' ranging patterns can provide critical information on the extent and possible effects of competition for food and space. We analyzed 12 years of daily ranging data and inter-group encounter data collected on 11 gorilla groups monitored by the Karisoke Research Center in Rwanda. During that period, the study population increased in size by almost 50% and the number of groups tripled. Groups had small yearly home ranges compared to other known gorilla populations, with an average 90% kernel density estimate of 8.07 km2 and large between-group variations (3.17-23.59 km2). Most groups had consistent home range location over the course of the study but for some, we observed gradual range shifts of up to 4 km. Neighboring groups displayed high home range overlap, which increased dramatically after the formation of new groups. On average, each group used only 28.6% of its 90% kernel home range exclusively, and in some areas up to six different groups had overlapping home ranges with little or no exclusive areas. We found a significant intra-group positive relationship between the number of weaned individuals in a group and the home range size, but the fitted models only explained 17.5% and 13.7% of the variance in 50% and 90% kernel home range size estimates, respectively. This suggests that despite the increase in size, the study population is not yet experiencing marked effects of feeding competition. However, the increase in home range overlap resulting from the formation of new groups led to a sixfold increase in the frequency of inter-group encounters, which exposes the population to elevated risks of fight-related injuries and infanticide.

  15. Dynamics of group knowledge production in facilitated modelling workshops

    DEFF Research Database (Denmark)

    Tavella, Elena; Franco, L. Alberto

    2015-01-01

    The term ‘facilitated modelling’ is used in the literature to characterise an approach to structuring problems, developing options and evaluating decisions by groups working in a model-supported workshop environment, and assisted by a facilitator. The approach involves an interactive process...... 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 form of three distinct group knowledge production patterns: generative, collaborative and assertive. Further, each pattern is characterised by a particular mix of communicative behaviours and model-supported interactions that has implications for the creation of new knowledge within the workshop. Our...

  16. 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.

  17. Random Group Problem-Based Learning in Engineering Dynamics

    CERN Document Server

    Fleischfresser, Luciano

    2014-01-01

    Dynamics problem solving is highly specific to the problem at hand and to develop the general mind framework to become an effective problem solver requires ingenuity and creativity on top of a solid grounding on theoretical and conceptual knowledge. A blended approach with prototype demo, problem-based learning, and an opinion questionnaire was used during first semester of 2013. Students working in randomly selected teams had to interact with classmates while solving a randomly selected problem. The approach helps improve awareness of what is important to learn in this class while reducing grading load. It also provides a more rewarding contact time for both pupils and instructor.

  18. Group-size-mediated habitat selection and group fusion-fission dynamics of bison under predation risk.

    Science.gov (United States)

    Fortin, Daniel; Fortin, Marie-Eve; Beyer, Hawthorne L; Duchesne, Thierry; Courant, Sabrina; Dancose, Karine

    2009-09-01

    For gregarious animals the cost-benefit trade-offs that drive habitat selection may vary dynamically with group size, which plays an important role in foraging and predator avoidance strategies. We examined how habitat selection by bison (Bison bison) varied as a function of group size and interpreted these patterns by testing whether habitat selection was more strongly driven by the competing demands of forage intake vs. predator avoidance behavior. We developed an analytical framework that integrated group size into resource selection functions (RSFs). These group-size-dependent RSFs were based on a matched case-control design and were estimated using conditional logistic regression (mixed and population-averaged models). Fitting RSF models to bison revealed that bison groups responded to multiple aspects of landscape heterogeneity and that selection varied seasonally and as a function of group size. For example, roads were selected in summer, but not in winter. Bison groups avoided areas of high snow water equivalent in winter. They selected areas composed of a large proportion of meadow area within a 700-m radius, and within those areas, bison selected meadows. Importantly, the strength of selection for meadows varied as a function of group size, with stronger selection being observed in larger groups. Hence the bison-habitat relationship depended in part on the dynamics of group formation and division. Group formation was most likely in meadows. In contrast, risk of group fission increased when bison moved into the forest and was higher during the time of day when movements are generally longer and more variable among individuals. We also found that stronger selection for meadows by large rather than small bison groups was caused by longer residence time in individual meadows by larger groups and that departure from meadows appears unlikely to result from a depression in food intake rate. These group-size-dependent patterns were consistent with the hypothesis

  19. Substructure in the Most Massive GEEC Groups: Field-like Populations in Dynamically Active Groups

    CERN Document Server

    Hou, Annie; Wilman, David J; McGee, Sean L; Harris, William E; Connelly, Jennifer L; Balogh, Michael L; Mulchaey, John S; Bower, Richard G

    2012-01-01

    The presence of substructure in galaxy groups and clusters is believed to be a sign of recent galaxy accretion and can be used not only to probe the assembly history of these structures, but also the evolution of their member galaxies. Using the Dressler-Shectman (DS) Test, we study substructure in a sample of intermediate redshift (z ~ 0.4) galaxy groups from the Group Environment and Evolution Collaboration (GEEC) group catalog. We find that 4 of the 15 rich GEEC groups, with an average velocity dispersion of ~525 km s-1, are identified as having significant substructure. The identified regions of localized substructure lie on the group outskirts and in some cases appear to be infalling. In a comparison of galaxy properties for the members of groups with and without substructure, we find that the groups with substructure have a significantly higher fraction of blue and star-forming galaxies and a parent colour distribution that resembles that of the field population rather than the overall group population....

  20. Theory of galaxy dynamics in clusters and groups

    CERN Document Server

    Mamon, G A

    2000-01-01

    Analytical estimates of the mass and radial dependence of the rates of galaxy mergers and of tidal interactions are derived for clusters and groups of galaxies, taking into account the tides from the system potential that limit the sizes of galaxies. Only high mass galaxies undergo significant major merging before being themselves cannibalized by more massive galaxies. Strong tides from the group/cluster potential severely limit the merger/tide cross-sections in the central regions, and while tides are most efficient at the periphery, one should see merging encounters further inside rich clusters.

  1. 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

  2. Dynamics of a Counseling Group: The Counselor as Leader

    Science.gov (United States)

    Glotzer, Shelly

    1973-01-01

    The counselor is important for effective functioning of a group. Many interactions evolve from his presence and the client's subsequent struggles to be dependent and independent. The various phases in this sturggle are explained as is their relation to Freudian theory. (EK)

  3. 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,…

  4. Ecological change, group territoriality, and population dynamics in Serengeti lions.

    Science.gov (United States)

    Packer, Craig; Hilborn, Ray; Mosser, Anna; Kissui, Bernard; Borner, Markus; Hopcraft, Grant; Wilmshurst, John; Mduma, Simon; Sinclair, Anthony R E

    2005-01-21

    Territorial behavior is expected to buffer populations against short-term environmental perturbations, but we have found that group living in African lions causes a complex response to long-term ecological change. Despite numerous gradual changes in prey availability and vegetative cover, regional populations of Serengeti lions remained stable for 10- to 20-year periods and only shifted to new equilibria in sudden leaps. Although gradually improving environmental conditions provided sufficient resources to permit the subdivision of preexisting territories, regional lion populations did not expand until short-term conditions supplied enough prey to generate large cohorts of surviving young. The results of a simulation model show that the observed pattern of "saltatory equilibria" results from the lions' grouping behavior.

  5. Facilitation by exogenous attention for static and dynamic gestalt groups.

    Science.gov (United States)

    Gonen, Fahrettin F; Hallal, Hamza; Ogmen, Haluk

    2014-08-01

    Attentional mechanisms allow the brain to selectively allocate its resources to stimuli of interest within the huge amount of information reaching its sensory systems. The voluntary component of attention, endogenous attention, can be allocated in a flexible manner depending on the goals and strategies of the observer. On the other hand, the reflexive component, exogenous attention, is driven by the stimulus. Here, we investigated how exogenous attention is deployed to moving stimuli that form distinct perceptual groups. We showed that exogenous attention is deployed according to a reference frame that moves along with the stimulus. Moreover, in addition to the cued stimulus, exogenous attention is deployed to all elements forming a perceptual group. These properties provide a basis for the efficient deployment of exogenous attention under ecological viewing conditions.

  6. Understanding the group dynamics and success of teams

    OpenAIRE

    Klug, Michael; Bagrow, James P.

    2014-01-01

    Complex problems often require coordinated group effort and can consume significant resources, yet our understanding of how teams form and succeed has been limited by a lack of large-scale, quantitative data. We analyse activity traces and success levels for approximately 150 000 self-organized, online team projects. While larger teams tend to be more successful, workload is highly focused across the team, with only a few members performing most work. We find that highly successful teams are ...

  7. Do group dynamics play a role in the evolution of member galaxies?

    CERN Document Server

    Hou, Annie; Balogh, Michael L; McGee, Sean L; Wilman, David J; Connelly, Jennifer L; Harris, William E; Mok, Angus; Mulchaey, John S; Bower, Richard G; Finoguenov, Alexis

    2013-01-01

    We examine galaxy groups from the present epoch to z = 1 to explore the impact of group dynamics on galaxy evolution. We use group catalagues from the Sloan Digital Sky Survey (SDSS), the Group Environment and Evolution Collaboration (GEEC) and the high redshift GEEC2 sample to study how the observed member properties depend on galaxy stellar mass, group dynamical mass and dynamical state of the host group. We find a strong correlation between the fraction of non-star-forming (quiescent) galaxies and galaxy stellar mass, but do not detect a significant difference in the quiescent fraction with group dynamical mass, within our sample halo mass range of 10^13-10^14.5 M_sun, or with dynamical sate. However, at a redshift of approximately 0.4 we do see some evidence that the quiescent fraction in low mass galaxies (log(M_star/M_sun) 10.5), evolution is most strongly correlated to the stellar mass of a galaxy with little or no additional effect related to either the group dynamical mass or dynamical state. For lo...

  8. Dynamics and applicability of the similarity renormalization group

    Energy Technology Data Exchange (ETDEWEB)

    Launey, K D; Dytrych, T; Draayer, J P [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Popa, G, E-mail: kristina@baton.phys.lsu.edu [Department of Physics and Astronomy, Ohio University, Zanesville, OH 43701 (United States)

    2012-01-13

    The similarity renormalization group (SRG) concept (or flow equations methodology) is studied with a view toward the renormalization of nucleon-nucleon interactions for ab initio shell-model calculations. For a general flow, we give quantitative measures, in the framework of spectral distribution theory, for the strength of the SRG-induced higher order (many-body) terms of an evolved interaction. Specifically, we show that there is a hierarchy among the terms, with those of the lowest particle rank being the most important. This feature is crucial for maintaining the unitarity of SRG transformations and key to the method's applicability. (paper)

  9. Swarm Dynamics of a Group of Mobile Autonomous Agents

    Institute of Scientific and Technical Information of China (English)

    LIU Bo; CHU Tian-Guang; WANG Long; WANG Zhan-Feng

    2005-01-01

    @@ We propose a simple swarm model to study collective behaviour ofa group of mobile autonomous agents interact ing through a long range attraction and short range repulsion function. It is shown that the individuals (agents) will aggregate and eventually form a cohesive cluster of finite size around the swarm centre in a finite time, and the size depends only on the parameters of the swarm model. Furthermore, it is also shown that all the individuals will converge to equilibrium positions of the swarm model, and thus the configuration of the swarm converges to a constant constellation. Numerical simulations are also worked out to illustrate the analytical results.

  10. 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.

  11. Psychoanalytic case presentations in a weaving thoughts group: on countertransference and group dynamics.

    Science.gov (United States)

    Salomonsson, Björn

    2012-08-01

    This article summarizes experiences of psychoanalytic case presentations in weaving thoughts (WT) peer groups. The format is presented and illustrated using a session with a group of analysts. In this setting, the frame of the presentation is guaranteed by the moderator. One aim is to create a group setting with many parallels to the analytic situation. A second aim is to discourage members from becoming enmeshed in destructive group functioning, such as internal disputes that may block a deeper understanding of the material. Classical psychoanalysis permits the analyst to reflect behind the patient on the transference-countertransference interplay. However, such reflections may be marred by undetected countertransference problems. Different supervision formats have different ways of helping the analyst with them. The WT format 'copies' the analytic session to the group, hence each member associates to the material in peace. Meanwhile the presenter looks, metaphorically speaking, at the web of their associations at his or her own pace. This may help him or her to confront and reflect on unresolved countertransference issues. This article indicates the method's similarities and differences compared with other formats. Arguments are supported by a child psychotherapy session, but the method is equally suitable for adult case material.

  12. Geometry of Dynamic Large Networks: A Scaling and Renormalization Group Approach

    Science.gov (United States)

    2013-12-11

    Geometry of Dynamic Large Networks - A Scaling and Renormalization Group Approach IRAJ SANIEE LUCENT TECHNOLOGIES INC 12/11/2013 Final Report...Z39.18 Final Performance Report Grant Title: Geometry of Dynamic Large Networks: A Scaling and Renormalization Group Approach Grant Award Number...test itself may be scaled to much larger graphs than those we examined via renormalization group methodology. Using well-understood mechanisms, we

  13. Understanding the group dynamics and success of teams.

    Science.gov (United States)

    Klug, Michael; Bagrow, James P

    2016-04-01

    Complex problems often require coordinated group effort and can consume significant resources, yet our understanding of how teams form and succeed has been limited by a lack of large-scale, quantitative data. We analyse activity traces and success levels for approximately 150 000 self-organized, online team projects. While larger teams tend to be more successful, workload is highly focused across the team, with only a few members performing most work. We find that highly successful teams are significantly more focused than average teams of the same size, that their members have worked on more diverse sets of projects, and the members of highly successful teams are more likely to be core members or 'leads' of other teams. The relations between team success and size, focus and especially team experience cannot be explained by confounding factors such as team age, external contributions from non-team members, nor by group mechanisms such as social loafing. Taken together, these features point to organizational principles that may maximize the success of collaborative endeavours.

  14. Dynamics of extinction debt across five taxonomic groups.

    Science.gov (United States)

    Halley, John M; Monokrousos, Nikolaos; Mazaris, Antonios D; Newmark, William D; Vokou, Despoina

    2016-07-25

    Species extinction following habitat loss is well documented. However, these extinctions do not happen immediately. The biodiversity surplus (extinction debt) declines with some delay through the process of relaxation. Estimating the time constants of relaxation, mainly the expected time to first extinction and the commonly used time for half the extinction debt to be paid off (half-life), is crucial for conservation purposes. Currently, there is no agreement on the rate of relaxation and the factors that it depends on. Here we find that half-life increases with area for all groups examined in a large meta-analysis of extinction data. A common pattern emerges if we use average number of individuals per species before habitat loss as an area index: for mammals, birds, reptiles and plants, the relationship has an exponent close to a half. We also find that the time to first determined extinction is short and increases slowly with area.

  15. Dynamical History of the Local Group in LCDM

    CERN Document Server

    Banik, Indranil

    2015-01-01

    The positions and velocities of galaxies in the Local Group (LG) measure the gravitational field within it. This is mostly due to the Milky Way (MW) and Andromeda (M31). We constrain their masses using a sample of 32 galaxies with measured distances and radial velocities (RVs). To do this, we follow the trajectories of several thousand simulated particles on a pure Hubble flow from redshift 9. For each observed galaxy, we obtain a trajectory which today is at the same position. Its final velocity is the model prediction for the velocity of that galaxy. We carefully consider the impact of tides raised by objects outside the LG. We directly include Centaurus A and try to account for IC 342 and M81. With our analysis, the total LG mass is $4.33^{+0.37}_{-0.32} \\times {10}^{12} M_\\odot$, with $0.20^{+0.05}_{-0}$ of this being in the MW. However, no plausible set of initial conditions yields a good match to the RVs of our sample of LG galaxies. We introduce a parameter $\\sigma_{extra}$ to quantify the typical disa...

  16. 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 systems...... at six large (230-450 cows) commercial Danish dairy herds. All six farms had both systems simultaneously in the same stall, and under identical management and feeding regimes. Calves in stable groups had significantly higher daily live weight gain than calves in dynamic groups (870 vs. 810 g...

  17. 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…

  18. 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…

  19. Locomotion Disorders and Skin and Claw Lesions in Gestating Sows Housed in Dynamic versus Static Groups

    Science.gov (United States)

    Bos, Emilie-Julie; Maes, Dominiek; van Riet, Miriam M. J.; Millet, Sam; Ampe, Bart; Janssens, Geert P. J.; Tuyttens, Frank A. M.

    2016-01-01

    Lameness and lesions to the skin and claws of sows in group housing are commonly occurring indicators of reduced welfare. Typically, these problems are more common in group housing than in individual housing systems. Group management type (dynamic versus static) and stage of gestation influence the behavior of the animals, which in turn influences the occurrence of these problems. The present study compared prevalence, incidence and mean scores of lameness and skin and claw lesions in static versus dynamic group housed sows at different stages of gestation during three consecutive reproductive cycles. A total of 10 Belgian sow herds were monitored; 5 in which dynamic groups and 5 in which static groups were utilized. All sows were visually assessed for lameness and skin lesions three times per cycle and the claws of the hind limbs were assessed once per cycle. Lameness and claw lesions were assessed using visual analogue scales. Static groups, in comparison with dynamic groups, demonstrated lower lameness scores (Psows demonstrating claw lesions regardless of group management. Prevalences of lameness (22.4 vs. 8.9%, P<0.05) and skin lesions (46.6 vs. 4.4%, P<0.05) were highest during the group-housed phase compared to the individually housed phases. Although the prevalence of lameness and skin lesions did not differ three days after grouping versus at the end of the group-housing phase, their incidence peaked during the first three days after moving from the insemination stalls to the group. In conclusion, the first three days after grouping was the most risky period for lameness incidence, but there was no significant difference between static or dynamic group management. PMID:27680675

  20. 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.

  1. Toward understanding and treating violence in America: some contributions from group dynamic and group therapy perspectives: introduction to part I.

    Science.gov (United States)

    Klein, Robert H; Schermer, Victor L

    2015-01-01

    The co-editors introduce a two-part Special Section of the Journal devoted to understanding and treating violence in America. They examine the relevance of clinical experience for contributions that can be made by group therapists and group dynamic thinkers to the growing national dialogue about this problem. The pervasive nature, causes, and different forms of violence in the United States are compared with those found in other countries. Underlying sociocultural values and myths, historical and current cultural contexts are considered breeding grounds for potential violence. How therapists can promote healthy change in their groups and in the broader society is explored. The articles contained in part one are reviewed against this backdrop.

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

    CERN Document Server

    Moussaid, Mehdi; Garnier, Simon; Helbing, Dirk; Theraulaz, Guy

    2010-01-01

    Human crowd motion is mainly driven by self-organized processes based on local interactions among pedestrians. While most studies of crowd behavior 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 ...

  3. Noether’s theorem for dissipative quantum dynamical semi-groups

    Energy Technology Data Exchange (ETDEWEB)

    Gough, John E., E-mail: jug@aber.ac.uk [Aberystwyth University, Aberystwyth SY23 3BZ, Wales (United Kingdom); Ratiu, Tudor S., E-mail: tudor.ratiu@epfl.ch [Section de Mathématiques and Bernoulli Center, École Polytechnique Fédérale de Lausanne, Lausanne CH 1015 (Switzerland); Smolyanov, Oleg G., E-mail: smolyanov@yandex.ru [Mechanics and Mathematics Faculty, Moscow State University, Moscow 119991 (Russian Federation)

    2015-02-15

    Noether’s theorem on constants of the motion of dynamical systems has recently been extended to classical dissipative systems (Markovian semi-groups) by Baez and Fong [J. Math. Phys. 54, 013301 (2013)]. We show how to extend these results to the fully quantum setting of quantum Markov dynamics. For finite-dimensional Hilbert spaces, we construct a mapping from observables to completely positive maps that leads to the natural analogue of their criterion of commutativity with the infinitesimal generator of the Markov dynamics. Using standard results on the relaxation of states to equilibrium under quantum dynamical semi-groups, we are able to characterise the constants of the motion under quantum Markov evolutions in the infinite-dimensional setting under the usual assumption of existence of a stationary strictly positive density matrix. In particular, the Noether constants are identified with the fixed point of the Heisenberg picture semi-group.

  4. 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…

  5. 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…

  6. Problem Based Learning as a Shared Musical Journey--Group Dynamics, Communication and Creativity

    Science.gov (United States)

    Lindvang, Charlotte; Beck, Bolette

    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 on group dynamic theory, and points out the…

  7. Nonequilibrium dynamics of active matter with correlated noise: A dynamical renormalization group study

    Science.gov (United States)

    Kachan, Devin; Levine, Alex; Bruinsma, Robijn

    2014-03-01

    Biology is rife with examples of active materials - soft matter systems driven into nonequilibrium steady states by energy input at the micro scale. For example, solutions of active micron scale swimmers produce active fluids showing phenomena reminiscent of turbulent convection at low Reynolds number; cytoskeletal networks driven by endogenous molecular motors produce active solids whose mechanics and low frequency strain fluctuations depend sensitively on motor activity. One hallmark of these systems is that they are driven at the micro scale by temporally correlated forces. In this talk, we study how correlated noise at the micro scale leads to novel long wavelength and long time scale dynamics at the macro scale in a simple model system. Specifically, we study the fluctuations of a ϕ4 scalar field obeying model A dynamics and driven by noise with a finite correlation time τ. We show that the effective dynamical system at long length and time scales is driven by white noise with a renormalized amplitude and renormalized transport coefficients. We discuss the implications of this result for a broad class of active matter systems driven at the micro scale by colored noise.

  8. Reproductive strategies and group dynamics in the genus \\kur{Acomys}.

    OpenAIRE

    ČÍŽKOVÁ, Barbora

    2012-01-01

    Reproductive behaviour and aspects of group dynamics in the genus Acomys were studied in the respect to the individuals? physical condition, life history traits and social environment. Three of the presented studies reveal the important effect of social environment on the behaviour of group members to the new-coming male and reproductive behaviour of females (sex ratio of the pups and litter size). The other two studies investigate the costs associated with group living and cooperative breedi...

  9. The Walking Behaviour of Pedestrian Social Groups and Its Impact on Crowd Dynamics

    Science.gov (United States)

    Moussaïd, Mehdi; Perozo, Niriaska; Garnier, Simon; Helbing, Dirk; Theraulaz, Guy

    2010-01-01

    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. PMID:20383280

  10. 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.

  11. Local group modes and the dynamics of intramolecular energy transfer across a heavy atom

    OpenAIRE

    Lopez, Vicente; Fairen, Victor; Lederman, Steven M.; Marcus, R.A

    1986-01-01

    The dynamics of energy transfer is discussed for a model system in which two ligands are separated by a heavy atom. Numerical and analytical results are given for the case that each ligand is a CC. In the quasiperiodic regime, the dynamics are interpreted using perturbation theory. Local group modes involved in an intramolecular energy localization which can occur in this regime are identified. An approximate separation of the primarily ligand–ligand motions from the primarily ligand–metal–li...

  12. 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.

  13. A modern artificial intelligence Playware art tool for psychological testing of group dynamics

    DEFF Research Database (Denmark)

    Pagliarini, Luigi; Lund, Henrik Hautop

    2015-01-01

    and the psychological findings. We describe the modern artificial intelligence implementation of this instrument. Between an art piece and a psychological test, at a first cognitive analysis, it seems to be a promising research tool. In the discussion we speculate about potential industrial applications, as well.......We describe an artistic method used for the psychological analysis of group dynamics. The design of the artistic system, which mediates group dynamics, emerges from our studies of modular Playware and remixing Playware. Inspired from remixing modular Playware, where users remix samples in the form...

  14. 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

    material and starting the feeding cycle in the evening for overnight feeding may improve behaviour in dynamic group housing systems with ESF. However, the benefits of starting the feeding cycle in the evening may depend on low disturbance in daytime from other management procedures......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...

  15. Experimental study on small group behavior and crowd dynamics in a tall office building evacuation

    Science.gov (United States)

    Ma, Yaping; Li, Lihua; Zhang, Hui; Chen, Tao

    2017-05-01

    It is well known that a large percentage of occupants in a building are evacuated together with their friends, families, and officemates, especially in China. Small group behaviors are therefore critical for crowd movement. This paper aims to study the crowd dynamic considering different social relations and the impacts of small groups on crowd dynamics in emergency evacuation. Three experiments are conducted in an 11-storey office building. In the first two experiments, all participants are classmates and know each other well. They are evacuated as individuals or pairs. In the third experiment, social relations among the participants are complex. Participants consist of 8 families, 6 lovers and several individuals. Space-time features, speed characteristics and density-speed relations for each experiment are analyzed and compared. Results conclude that small group behaviors can make positive impacts on crowd dynamics when evacuees know each other and are cooperative. This conclusion is also testified by four verified experiments. In the third experiment, speeds of evacuees are lowest. Small groups form automatically with the presence of intimate social relations. Small groups in this experiment slow down the average speed of the crowd and make disturbance on the crowd flow. Small groups in this case make negative impacts on the movement of the crowd. It is because that evacuees do not know each other and they are competitive to each other. Characteristics of different types of small groups are also investigated. Experimental data can provide foundational parameters for evacuation model development and are helpful for building designers.

  16. Problembased learning as a shared musical journey - group dynamics, communication and creativity

    DEFF Research Database (Denmark)

    Lindvang, Charlotte; Beck, Bolette Daniels

    2015-01-01

    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...... 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...

  17. Molecular group dynamics study on slip flow of thin fluid film based on the Hamaker hypotheses

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The thin fluid film was assumed to consist of a number of spherical fluid molecular groups and the attractive forces of molecular group pairs were calculated by the derived equation according to the three Hamaker homogeneous material hypotheses. Regarding each molecular group as a dynamics individual, the simulation method for the shearing motion of multilayer fluid molecular groups, which was initiated by two moving walls, was proposed based on the Verlet velocity iterative algorithm. The simulations reveal that the velocities of fluid molecular groups change about their respective mean velocities within a narrow range in steady state. It is also found that the velocity slips occur at the wall boundary and in a certain number of fluid film layers close to the wall. Because the dimension of molecular group and the number of group layers are not restricted, the hypothetical thickness of fluid film model can be enlarged from nanometer to micron by using the proposed simulation method.

  18. 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.

  19. 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.

  20. Low-temperature hopping dynamics with energy disorder: renormalization group approach.

    Science.gov (United States)

    Velizhanin, Kirill A; Piryatinski, Andrei; Chernyak, Vladimir Y

    2013-08-28

    We formulate a real-space renormalization group (RG) approach for efficient numerical analysis of the low-temperature hopping dynamics in energy-disordered lattices. The approach explicitly relies on the time-scale separation of the trapping/escape dynamics. This time-scale separation allows to treat the hopping dynamics as a hierarchical process, RG step being a transformation between the levels of the hierarchy. We apply the proposed RG approach to analyze hopping dynamics in one- and two-dimensional lattices with varying degrees of energy disorder, and find the approach to be accurate at low temperatures and computationally much faster than the brute-force direct diagonalization. Applicability criteria of the proposed approach with respect to the time-scale separation and the maximum number of hierarchy levels are formulated. RG flows of energy distribution and pre-exponential factors of the Miller-Abrahams model are analyzed.

  1. Individualistic Striving and Group Dynamics of Fifth- and Eighth-Grade Japanese Boys.

    Science.gov (United States)

    Shwalb, David W.; And Others

    1991-01-01

    Individualistic and competitive striving and group dynamics were compared for 42 fifth grade and 42 eighth grade Japanese boys in central Tokyo using a card-stacking procedure. Results are discussed in terms of social loafing versus social striving and behavior patterns of Japanese adults. (SLD)

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

    Science.gov (United States)

    Leclercq, Sébastien; Cordaux, Richard

    2012-01-01

    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.

  3. 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.

  4. Sociometry: An Approach for Assessing Group Dynamics in Web-Based Courses

    Science.gov (United States)

    Daugherty, Martha; Turner, Jeff

    2003-01-01

    Student interactivity in web-based educational environments has shown to increase academic learning and motivation (Jiang, 1998; Petraglia, 1998). However, instructors often find it difficult to assess the quality of online group dynamics without visual observations of student behaviors. The purpose of this study was to investigate the use of…

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

    Energy Technology Data Exchange (ETDEWEB)

    Hedegård, Erik Donovan, E-mail: erik.hedegard@phys.chem.ethz.ch; Knecht, Stefan; Reiher, Markus, E-mail: markus.reiher@phys.chem.ethz.ch [Laboratorium für Physikalische Chemie, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich (Switzerland); Kielberg, Jesper Skau; Jensen, Hans Jørgen Aagaard, E-mail: hjj@sdu.dk [Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, Odense (Denmark)

    2015-06-14

    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 electron-correlation effects in multiconfigurational electronic structure problems.

  6. 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...

  7. Density Matrix Renormalization Group with Efficient Dynamical Electron Correlation Through Range Separation

    CERN Document Server

    Hedegård, Erik Donovan; Kielberg, Jesper Skau; Jensen, Hans Jørgen Aagaard; Reiher, Markus

    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 electron-correlation effects in multiconfigurational electronic structure problems.

  8. Influence of the leaving group on the dynamics of a gas-phase SN2 reaction

    Science.gov (United States)

    Stei, Martin; Carrascosa, Eduardo; Kainz, Martin A.; Kelkar, Aditya H.; Meyer, Jennifer; Szabó, István; Czakó, Gábor; Wester, Roland

    2016-02-01

    In addition to the nucleophile and solvent, the leaving group has a significant influence on SN2 nucleophilic substitution reactions. Its role is frequently discussed with respect to reactivity, but its influence on the reaction dynamics remains unclear. Here, we uncover the influence of the leaving group on the gas-phase dynamics of SN2 reactions in a combined approach of crossed-beam imaging and dynamics simulations. We have studied the reaction F- + CH3Cl and compared it to F- + CH3I. For the two leaving groups, Cl and I, we find very similar structures and energetics, but the dynamics show qualitatively different features. Simple scaling of the leaving group mass does not explain these differences. Instead, the relevant impact parameters for the reaction mechanisms are found to be crucial and the differences are attributed to the relative orientation of the approaching reactants. This effect occurs on short timescales and may also prevail in solution-phase conditions.

  9. Dynamical symmetry breaking in chiral gauge theories with direct-product gauge groups

    Science.gov (United States)

    Shi, Yan-Liang; Shrock, Robert

    2016-09-01

    We analyze patterns of dynamical symmetry breaking in strongly coupled chiral gauge theories with direct-product gauge groups G . If the gauge coupling for a factor group Gi⊂G becomes sufficiently strong, it can produce bilinear fermion condensates that break the Gi symmetry itself and/or break other gauge symmetries Gj⊂G . Our comparative study of a number of strongly coupled direct-product chiral gauge theories elucidates how the patterns of symmetry breaking depend on the structure of G and on the relative sizes of the gauge couplings corresponding to factor groups in the direct product.

  10. Dynamical Symmetry Breaking in Chiral Gauge Theories with Direct-Product Gauge Groups

    CERN Document Server

    Shi, Yan-Liang

    2016-01-01

    We analyze patterns of dynamical symmetry breaking in strongly coupled chiral gauge theories with direct-product gauge groups $G$. If the gauge coupling for a factor group $G_i \\subset G$ becomes sufficiently strong, it can produce bilinear fermion condensates that break the $G_i$ symmetry itself and/or break other gauge symmetries $G_j \\subset G$. Our comparative study of a number of strongly coupled direct-product chiral gauge theories elucidates how the patterns of symmetry breaking depend on the structure of $G$ and on the relative sizes of the gauge couplings corresponding to factor groups in the direct product.

  11. Dynamic Multicast Grouping Approach in HLA-Based Distributed Interactive Simulation

    Institute of Scientific and Technical Information of China (English)

    DAI Zhong-jian; HOU Chao-zhen

    2005-01-01

    In order to improve the efficiency of data distributed management service in distributed interactive simulation based on high level architecture (HLA) and to reduce the network traffic and save the system resource, the approaches of multicast grouping in HLA-based distributed interactive simulation are discussed. Then a new dynamic multicast grouping approach is proposed. This approach is based on the current publication and subscription region in the process of simulation. The results of simulation experiment show that this approach can significantly reduce the message overhead and use fewer multicast groups.

  12. Human group formation in online guilds and offline gangs driven by a common team dynamic.

    Science.gov (United States)

    Johnson, Neil F; Xu, Chen; Zhao, Zhenyuan; Ducheneaut, Nicolas; Yee, Nicholas; Tita, George; Hui, Pak Ming

    2009-06-01

    Quantifying human group dynamics represents a unique challenge. Unlike animals and other biological systems, humans form groups in both real (offline) and virtual (online) spaces-from potentially dangerous street gangs populated mostly by disaffected male youths to the massive global guilds in online role-playing games for which membership currently exceeds tens of millions of people from all possible backgrounds, age groups, and genders. We have compiled and analyzed data for these two seemingly unrelated offline and online human activities and have uncovered an unexpected quantitative link between them. Although their overall dynamics differ visibly, we find that a common team-based model can accurately reproduce the quantitative features of each simply by adjusting the average tolerance level and attribute range for each population. By contrast, we find no evidence to support a version of the model based on like-seeking-like (i.e., kinship or "homophily").

  13. Human group formation in online guilds and offline gangs driven by a common team dynamic

    Science.gov (United States)

    Johnson, Neil F.; Xu, Chen; Zhao, Zhenyuan; Ducheneaut, Nicolas; Yee, Nicholas; Tita, George; Hui, Pak Ming

    2009-06-01

    Quantifying human group dynamics represents a unique challenge. Unlike animals and other biological systems, humans form groups in both real (offline) and virtual (online) spaces—from potentially dangerous street gangs populated mostly by disaffected male youths to the massive global guilds in online role-playing games for which membership currently exceeds tens of millions of people from all possible backgrounds, age groups, and genders. We have compiled and analyzed data for these two seemingly unrelated offline and online human activities and have uncovered an unexpected quantitative link between them. Although their overall dynamics differ visibly, we find that a common team-based model can accurately reproduce the quantitative features of each simply by adjusting the average tolerance level and attribute range for each population. By contrast, we find no evidence to support a version of the model based on like-seeking-like (i.e., kinship or “homophily”).

  14. Scaled Group Consensus in Multiagent Systems With First/Second-Order Continuous Dynamics.

    Science.gov (United States)

    Yu, Junyan; Shi, Yang

    2017-08-29

    We investigate scaled group consensus problems of multiagent systems with first/second-order linear continuous dynamics. For a complex network consisting of two subnetworks with different physical quantities or task distributions, it is concerned with this case that the agents' states in one subnetwork converge to a consistent value asymptotically, while the states in the other subnetwork approach another value with a ratio of the former. For the case of the information exchange being directed, novel consensus protocols are designed for both first-order and second-order dynamics to solve the scaled group consensus problems. By utilizing algebra theory, graph theory, and Lyapunov stability theory, several necessary and sufficient conditions are established to guarantee the agents' states reaching the scaled group consensus asymptotically. Finally, several simulation results are presented to demonstrate the effectiveness of the theoretical results.

  15. Dynamical evolution and spectral characteristics of the stellar group Mamajek 2

    CERN Document Server

    Jilinski, E; De la Reza, R; Drake, N A; Bazzanella, B

    2008-01-01

    The dynamical evolution of the recently detected stellar group Mamajek 2 is studied by means of its past 3D orbit. The past orbits of the open clusters NGC 2516 and $\\alpha$ Persei, belonging to the so-called "Local Association", were also computed in order to check for a possible common past dynamical evolution of these systems. To complete the data of the Mamajek 2 small group, we have obtained high resolution FEROS spectra to measure the radial and also the projected rotational velocities of its members; an estimate of its metallicity was obtained as well. Two exceptionally low rotating A-type stars turned out to be a strong magnetic Ap star in one case, and a normal A0 star with near-solar metallicity in the other. The dynamical results showed that NGC 2516 and Mamajek 2 may have had a common origin at the age of 135 $\\pm$ 5 Myr. This dynamical age confirms the individual ages of 140 Myr for NGC 2516 and 120 $\\pm$ 25 Myr for Mamajek 2 obtained independently by photometric methods. Both these groups appear...

  16. 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.

  17. 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.

  18. 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...... 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...

  19. 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.

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

    Institute of Scientific and Technical Information of China (English)

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

    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.

  1. 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.

    2017-01-01

    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, DGP and quintessence N-body simulations together with their ΛCDM counterparts featuring the same initial random phase realisations. The variables and intervals used to define LG-like objects are referred to as Local Group 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%, peaking well outside of the 95% 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.

  2. Terrorist Group Dynamics Through the Lens of the Tigantourine Assault in Algeria

    Directory of Open Access Journals (Sweden)

    Richard J. Chasdi

    2013-07-01

    Full Text Available The Algerian terrorist assault in January 2013 that was carried out by Mokhtar Belmokhtar and his “Battalion of Blood” activists against a BP-Norwegian-Algerian-Japanese gas facility in In Amenas, Algeria, is worth considering as it provides a rare glimpse into several key dimensions of terrorist group dynamics that are important for scholars and counter- terrorism practitioners to understand.

  3. A Novel Bit-level Image Encryption Method Based on Chaotic Map and Dynamic Grouping

    Institute of Scientific and Technical Information of China (English)

    张国基; 沈彦

    2012-01-01

    In this paper,a novel bit-level image encryption method based on dynamic grouping is proposed.In the proposed method,the plain-image is divided into several groups randomly,then permutation-diffusion process on bit level is carried out.The keystream generated by logistic map is related to the plain-image,which confuses the relationship between the plain-image and the cipher-image.The computer simulation results of statistical analysis,information entropy analysis and sensitivity analysis show that the proposed encryption method is secure and reliable enough to be used for communication application.

  4. Internal character dictates phase transition dynamics between isolation and cohesive grouping

    CERN Document Server

    Manrique, Pedro D; Johnson, Neil F

    2015-01-01

    We show that accounting for internal character among interacting, heterogeneous entities generates rich phase transition behavior between isolation and cohesive dynamical grouping. Our analytical and numerical calculations reveal different critical points arising for different character-dependent grouping mechanisms. These critical points move in opposite directions as the population's diversity decreases. Our analytical theory helps explain why a particular class of universality is so common in the real world, despite fundamental differences in the underlying entities. Furthermore, it correctly predicts the non-monotonic temporal variation in connectivity observed recently in one such system.

  5. On the new member's subsecret distribution protocol in dynamic group secret-sharing

    Institute of Scientific and Technical Information of China (English)

    LI Cheng; WANG Wei-nong

    2005-01-01

    Secret-sharing is a common method to protect important data, such as the private key of a public-key system. Dynamic Group Secret-sharing (DGS) is a system where all of the members in a group hold a subsecret of the key information and where the number of members in the group is variable. This kind of secret-sharing is broadly used in many special distribution systems, such as Self-secure Ad-hoc Network. Distributing this subsecret to a new member when he enters the group is the common method that ensures all the members participate in the same secret-sharing. However, no' atisfactory subsecret distribution scheme exists at present. This paper proposes a new protocol that tries to satisfy both security and efficiency.

  6. Context and group dynamics in a CBPR-developed HIV prevention intervention.

    Science.gov (United States)

    Dickson-Gomez, Julia; Corbett, A Michelle; Bodnar, Gloria; Zuniga, Maria Ofelia; Guevara, Carmen Eugenia; Rodriguez, Karla; Navas, Verónica

    2016-03-01

    This paper will explore in detail the effects of context and group dynamics on the development of a multi-level community-based HIV prevention intervention for crack cocaine users in the San Salvador Metropolitan Area, El Salvador. Community partners included residents from marginal communities, service providers from the historic center of San Salvador and research staff from a non-profit organization. The community contexts from which partners came varied considerably and affected structural group dynamics, i.e. who was identified as community partners, their research and organizational capacity, and their ability to represent their communities, with participants from marginal communities most likely to hold community leadership positions and be residents, and those from the center of San Salvador most likely to work in religious organizations dedicated to HIV prevention or feeding indigent drug users. These differences also affected the intervention priorities of different partners. The context of communities changed over time, particularly levels of violence, and affected group dynamics and the intervention developed. Finally, strategies were needed to elicit input from stakeholders under-represented in the community advisory board, in particular active crack users, in order to check the feasibility of the proposed intervention and revise it as necessary. Because El Salvador is a very different context than that in which most CBPR studies have been conducted, our results reveal important contextual factors and their effects on partnerships not often considered in the literature.

  7. 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.

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

    CERN Document Server

    Nobi, Ashadun

    2015-01-01

    We study the dynamic interactions and structural changes in global financial indices in the years 1998-2012. We apply a principal component analysis (PCA) to cross-correlation coefficients of the stock indices. We calculate the correlations between principal components (PCs) and each asset, known as PC coefficients. A change in market state is identified as a change in the first PC coefficients. Some indices do not show significant change of PCs in market state during crises. The indices exposed to the invested capitals in the stock markets are at the minimum level of risk. 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 spa...

  9. The Italian Red Brigades and the structure and dynamics of terrorist groups.

    Science.gov (United States)

    Tarantelli, Carole Beebe

    2010-06-01

    One of the problems in dealing with terrorism is that we have virtually no access to individual terrorists; only their actions are visible. The founders of the Italian terrorist group, the Red Brigades, on the other hand, have written about their experiences and have exhaustively explained their motivations. The author's premise is that these autobiographies and her interviews with several of the group's members give us access to the unconscious processes involved in the formation and operation of the group. After terrorist attacks, it is natural to ask whether the terrorists' capacity for collective violence is an indication of personal pathology. This paper argues that the relevant pathology in the terrorist enterprise is not that of the individual but that of the group. Relying on the theories of groups of Freud (1921), Bion (1961), Anzieu (1984) and Kaes (2007), the author argues that psychoanalytic theory is essential to understanding the motivations and actions of violent groups which otherwise remain obscure. Although the discussion has been confined to one terrorist group, the author hopes that it can also be useful for understanding the unconscious dynamics of other groups structured around an ideology which mandates the destruction of human life.

  10. 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.

  11. A Comparison of the Effects of Group Dynamics on Individuals Assigned to Integral and Non-Integral Aircrews.

    Science.gov (United States)

    1987-09-01

    34 Journal of Applied Behavioral Science, 10: 149-165(1974). Cartwright , Dorwin and Alvin Zander. Group Dynamics Research and Theory. Row, Peterson and...Company, Evanston IL 1953. Cartwright , Dorwin and Alvin Zander. "The Nature of Group Cohesiveness," Group Dynamics, 91-109. Harper and Row, New York...other reasons. Cartwright and Zander propose that groups may either facilitate or inhibit tne attainment of desirable social objectives ( Cartwright and

  12. Group Dynamics of Zebra and Wildebeest in a Woodland Savanna: Effects of Predation Risk and Habitat Density

    OpenAIRE

    Maria Thaker; Vanak, Abi T.; Cailey R. Owen; Monika B. Ogden; Rob Slotow

    2010-01-01

    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...

  13. The interaction between electrolyte and surfaces decorated with charged groups: A molecular dynamics simulation study.

    Science.gov (United States)

    Calero, Carles; Faraudo, Jordi

    2010-01-14

    In this paper, we perform molecular dynamics simulations of an interface containing charged functional groups of different valences in contact with 2:1 ionic solution. We take into account both the finite sizes of the ions in solution and the functional groups but we neglect the structural details of the solvent (primitive model). We show that the distribution of ions and the electrostatic properties of the system depend strongly on the valence of the interfacial charged groups. In the case of surfaces containing well-separated charged interfacial groups, we observe counterion binding at these groups induced by electrostatic interactions. A detailed analysis of the potential of mean force between interfacial charged groups and ions reveals significant features not anticipated by present theories of electrolytes near interfaces. Overall, our results show that, in primitive models of the ion-interface interaction, not only the ionic size and valence are important but the size and valence of the interfacial charged groups also have a significant impact.

  14. Dynamics of heterorhizic root systems: protoxylem groups within the fine-root system of Chamaecyparis obtusa.

    Science.gov (United States)

    Hishi, Takuo; Takeda, Hiroshi

    2005-08-01

    To understand the physiology of fine-root functions in relation to soil organic sources, the heterogeneity of individual root functions within a fine-root system requires investigation. Here the heterogeneous dynamics within fine-root systems are reported. The fine roots of Chamaecyparis obtusa were sampled using a sequential ingrowth core method over 2 yr. After color categorization, roots were classified into protoxylem groups from anatomical observations. The root lengths with diarch and triarch groups fluctuated seasonally, whereas the tetrarch root length increased. The percentage of secondary root mortality to total mortality increased with increasing amounts of protoxylem. The carbon : nitrogen ratio indicated that the decomposability of primary roots might be greater than that of secondary roots. The position of diarch roots was mostly apical, whereas tetrarch roots tended to be distributed in basal positions within the root architecture. We demonstrate the heterogeneous dynamics within a fine-root system of C. obtusa. Fine-root heterogeneity should affect soil C dynamics. This heterogeneity is determined by the branching position within the root architecture.

  15. 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.

  16. Dynamical analysis of strong-lensing galaxy groups at intermediate redshift

    CERN Document Server

    Muñoz, R P; Verdugo, T; Garrido, F; Limousin, M; Padilla, N; Foëx, G; Cabanac, R; Gavazzi, R; Barrientos, L F; Richard, J

    2012-01-01

    We present VLT spectroscopic observations of 7 discovered galaxy groups between 0.3groups were selected from the Strong Lensing Legacy Survey (SL2S), a survey that consists in a systematic search for strong lensing systems in the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). We give details about the target selection, spectroscopic observations and data reduction for the first release of confirmed SL2S groups. The dynamical analysis of the systems reveals that they are gravitationally bound structures, with at least 4 confirmed members and velocity dispersions between 300 and 800 km/s. Their virial masses are between 10^13 and 10^14 M_sun, and so can be classified as groups or low mass clusters. Most of the systems are isolated groups, except two of them that show evidence of an ongoing merger of two sub-structures. We find a good agreement between the velocity dispersions estimated from the analysis of the kinematics of group galaxies and the weak lensing measurements, and conclude...

  17. Disentangling the impact of social groups on response times and movement dynamics in evacuations.

    Science.gov (United States)

    Bode, Nikolai W F; Holl, Stefan; Mehner, Wolfgang; Seyfried, Armin

    2015-01-01

    Crowd evacuations are paradigmatic examples for collective behaviour, as interactions between individuals lead to the overall movement dynamics. Approaches assuming that all individuals interact in the same way have significantly improved our understanding of pedestrian crowd evacuations. However, this scenario is unlikely, as many pedestrians move in social groups that are based on friendship or kinship. We test how the presence of social groups affects the egress time of individuals and crowds in a representative crowd evacuation experiment. Our results suggest that the presence of social groups increases egress times and that this is largely due to differences at two stages of evacuations. First, individuals in social groups take longer to show a movement response at the start of evacuations, and, second, they take longer to move into the vicinity of the exits once they have started to move towards them. Surprisingly, there are no discernible time differences between the movement of independent individuals and individuals in groups directly in front of the exits. We explain these results and discuss their implications. Our findings elucidate behavioural differences between independent individuals and social groups in evacuations. Such insights are crucial for the control of crowd evacuations and for planning mass events.

  18. Disentangling the impact of social groups on response times and movement dynamics in evacuations.

    Directory of Open Access Journals (Sweden)

    Nikolai W F Bode

    Full Text Available Crowd evacuations are paradigmatic examples for collective behaviour, as interactions between individuals lead to the overall movement dynamics. Approaches assuming that all individuals interact in the same way have significantly improved our understanding of pedestrian crowd evacuations. However, this scenario is unlikely, as many pedestrians move in social groups that are based on friendship or kinship. We test how the presence of social groups affects the egress time of individuals and crowds in a representative crowd evacuation experiment. Our results suggest that the presence of social groups increases egress times and that this is largely due to differences at two stages of evacuations. First, individuals in social groups take longer to show a movement response at the start of evacuations, and, second, they take longer to move into the vicinity of the exits once they have started to move towards them. Surprisingly, there are no discernible time differences between the movement of independent individuals and individuals in groups directly in front of the exits. We explain these results and discuss their implications. Our findings elucidate behavioural differences between independent individuals and social groups in evacuations. Such insights are crucial for the control of crowd evacuations and for planning mass events.

  19. Context-aware adaptation for group communication support applications with dynamic architecture

    CERN Document Server

    Rodriguez, Ismael Bouassida; Chassot, Christophe; Jmaiel, Mohamed

    2008-01-01

    In this paper, we propose a refinement-based adaptation approach for the architecture of distributed group communication support applications. Unlike most of previous works, our approach reaches implementable, context-aware and dynamically adaptable architectures. To model the context, we manage simultaneously four parameters that influence Qos provided by the application. These parameters are: the available bandwidth, the exchanged data communication priority, the energy level and the available memory for processing. These parameters make it possible to refine the choice between the various architectural configurations when passing from a given abstraction level to the lower level which implements it. Our approach allows the importance degree associated with each parameter to be adapted dynamically. To implement adaptation, we switch between the various configurations of the same level, and we modify the state of the entities of a given configuration when necessary. We adopt the direct and mediated Producer-...

  20. Numerical renormalization group for the bosonic single-impurity Anderson model: Dynamics

    Science.gov (United States)

    Lee, Hyun-Jung; Byczuk, Krzysztof; Bulla, Ralf

    2010-08-01

    The bosonic single-impurity Anderson model (B-SIAM) is studied to understand the local dynamics of an atomic quantum dot (AQD) coupled to a Bose-Einstein condensation (BEC) state, which can be implemented to probe the entanglement and the decoherence of a macroscopic condensate. Our recent approach of the numerical renormalization-group calculation for the B-SIAM revealed a zero-temperature phase diagram, where a Mott phase with local depletion of normal particles is separated from a BEC phase with enhanced density of the condensate. As an extension of the previous work, we present the calculations of the local dynamical quantities of the B-SIAM which reinforce our understanding of the physics in the Mott and the BEC phases.

  1. Cooperative dynamics in the penetration of a group of intruders in a granular medium.

    Science.gov (United States)

    Pacheco-Vázquez, F; Ruiz-Suárez, J C

    2010-11-23

    An object moving in a fluid experiences a drag force that depends on its velocity, shape and the properties of the medium. From this simplest case to the motion of a flock of birds or a school of fish, the drag forces and the hydrodynamic interactions determine the full dynamics of the system. Similar drag forces appear when a single projectile impacts and moves through a granular medium, and this case is well studied in the literature. On the other hand, the case in which a group of intruders impact a granular material has never been considered. Here, we study the simultaneous penetration of several intruders in a very low-density granular medium. We find that the intruders move through it in a collective way, following a cooperative dynamics, whose complexity resembles flocking phenomena in living systems or the movement of reptiles in sand, wherein changes in drag are exploited to efficiently move or propel.

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

    Science.gov (United States)

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

    2013-04-01

    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 R0 is derived and the global dynamics of the model are established. It is shown that if R0 is less than or equal to 1, the disease-free equilibrium is globally asymptotically stable and the worm dies out eventually, whereas, if R0 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.

  3. Viscosity of heptane-toluene mixtures. Comparison of molecular dynamics and group contribution methods.

    Science.gov (United States)

    Velásquez, Ana Milena; Hoyos, Bibian A

    2017-02-01

    Three methods of molecular dynamics simulation [Green-Kubo (G-K), non-equilibrium molecular dynamics (NEMD) and reversed non-equilibrium molecular dynamics (RNEMD)], and two group contribution methods [UNIFAC-VISCO and Grunberg-Nissan (G-N)] were used to calculate the viscosity of mixtures of n-heptane and toluene (known as heptol). The results obtained for the viscosity and density of heptol were compared with reported experimental data, and the advantages and disadvantages of each method are discussed. Overall, the five methods showed good agreement between calculated and experimental viscosities. In all cases, the deviation was lower than 9%. It was found that, as the concentration of toluene increases, the deviation of the density of the mixture (as calculated with molecular dynamics methods) also increases, which directly affects the viscosity result obtained. Among the molecular simulation techniques evaluated here, G-K produced the best results, and represents the optimal balance between quality of result and time required for simulation. The NEMD method produced acceptable results for the viscosity of the system but required more simulation time as well as the determination of an appropriate shear rate. The RNEMD method was fast and eliminated the need to determine a set of values for shear rate, but introduced large fluctuations in measurements of shear rate and viscosity. The two group contribution methods were accurate and fast when used to calculate viscosity, but require knowledge of the viscosity of the pure compounds, which is a serious limitation for applications in complex multicomponent systems.

  4. 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.)

  5. Report of the working group on production and dynamics of high brightness beams

    Energy Technology Data Exchange (ETDEWEB)

    Sheffield, R.L. [MS H851I, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Bisognano, J.; Brau, C.; Hogan, M.; Kim, K.; Milton, S.; Nuhn, H.; Pagani, C.; Pierini, P.; Reiser, M.; Schmerge, J.; Serafini, L.; Teng, L.; Winick, H.; Cornacchia, M.

    1997-02-01

    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, 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, and the present status of the theoretical modeling of beam transport in bends. {copyright} {ital 1997 American Institute of Physics.}

  6. Dynamical chiral symmetry breaking and weak nonperturbative renormalization group equation in gauge theory

    CERN Document Server

    Aoki, Ken-Ichi; Sato, Daisuke

    2016-01-01

    We analyze the dynamical chiral symmetry breaking in gauge theory with the nonperturbative renormalization group equation (NPRGE), which is a first order nonlinear partial differential equation (PDE). In case that the spontaneous chiral symmetry breaking occurs, the NPRGE encounters some non-analytic singularities at the finite critical scale even though the initial function is continuous and smooth. Therefore there is no usual solution of the PDE beyond the critical scale. In this paper, we newly introduce the notion of a weak solution which is the global solution of the weak NPRGE. We show how to evaluate the physical quantities with the weak solution.

  7. Reduced Dynamics from the Unitary Group to Some Flag Manifolds : Interacting Matrix Riccati Equations

    CERN Document Server

    Fujii, Kazuyuki

    2008-01-01

    In this paper we treat the time evolution of unitary elements in the N level system and consider the reduced dynamics from the unitary group U(N) to flag manifolds of the second type (in our terminology). Then we derive a set of differential equations of matrix Riccati types interacting with one another and present an important problem on a nonlinear superposition formula that the Riccati equation satisfies. Our result is a natural generalization of the paper {\\bf Chaturvedi et al} (arXiv : 0706.0964 [quant-ph]).

  8. Universal short-time dynamics: Boundary functional renormalization group for a temperature quench

    Science.gov (United States)

    Chiocchetta, Alessio; Gambassi, Andrea; Diehl, Sebastian; Marino, Jamir

    2016-11-01

    We present a method to calculate short-time nonequilibrium universal exponents within the functional-renormalization-group scheme. As an example, we consider the classical critical dynamics of the relaxational model A after a quench of the temperature of the system and calculate the initial-slip exponent which characterizes the nonequilibrium universal short-time behavior of both the order parameter and correlation functions. The value of this exponent is found to be consistent with the result of a perturbative dimensional expansion and of Monte Carlo simulations in three spatial dimensions.

  9. 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.

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

    Directory of Open Access Journals (Sweden)

    Karlo Hock

    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.

  11. Group Dynamics in Top Management Teams: Groupthink, Vigilance, and Alternative Models of Organizational Failure and Success.

    Science.gov (United States)

    Peterson; Owens; Tetlock; Fan; Martorana

    1998-02-01

    This study explored the heuristic value of Janis' (1982) groupthink and vigilant decision making models as explanations of failure and success in top management team decision making using the Organizational Group Dynamics Q-sort (GDQ). Top management teams of seven Fortune 500 companies were examined at two historical junctures-one when the team was successful (defined as satisfying strategic constituencies) and one when the team was unsuccessful. Results strongly supported the notion that a group' decision making process is systematically related to the outcomes experienced by the team. Ideal-type Q-sorts organized around Janis' analysis of groupthink and vigilance were substantially correlated with Q-sorts of failing and successful groups, respectively. The fit was, however, far from perfect. Ideal-type Q-sorts derived from other frameworks correlated better with the failure-success classification than did the Janis-derived ideal types. Successful groups showed some indicators of groupthink (e.g., risk-taking, cohesion, and strong, opinionated leaders), whereas unsuccessful groups showed signs of vigilance (e.g., internal debate to the point of factionalism). The results illustrate the usefulness of the GDQ for developing and empirically testing theory in organizational behavior from historical cases. Copyright 1998 Academic Press.

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

    Science.gov (United States)

    Hock, Karlo; Ng, Kah Loon; Fefferman, Nina H

    2010-12-23

    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.

  13. Systems Approach to Studying Animal Sociality: Individual Position versus Group Organization in Dynamic Social Network Models

    Science.gov (United States)

    Hock, Karlo; Ng, Kah Loon; Fefferman, Nina H.

    2010-01-01

    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. PMID:21203425

  14. Collision Prevention Platform for a Dynamic Group of Asynchronous Cooperative Mobile Robots

    Directory of Open Access Journals (Sweden)

    Rami Yared

    2007-08-01

    Full Text Available This paper presents a fail-safe platform on which cooperative mobile robots rely for their motion. The platform consists of a collision prevention protocol for a dynamic group of cooperative mobile robots with asynchronous communications. The collision prevention protocol is timefree, in the sense that it never relies on physical time, which makes it extremely robust for timing uncertainty common in wireless networks. It guarantees that no two robots ever collide, regardless of the respective activities of the robots. The protocol is based on a fully distributed path reservation system. It assumes a mobile ad hoc network formed by the robots themselves, and takes advantage of the inherent locality of the problem in order to reduce communication. The protocol requires neither initial nor complete knowledge of the composition of the group. A performance analysis of the protocol provides insights for a proper dimensioning of system parameters in order to maximize the average effective speed of the robots.

  15. 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.

  16. Constraints on the dynamical evolution of the galaxy group M81

    Science.gov (United States)

    Oehm, W.; Thies, I.; Kroupa, P.

    2017-01-01

    According to the standard model of cosmology, galaxies are embedded in dark matter halos which are made of particles beyond the standard model of particle physics, thus extending the mass and the size of the visible baryonic matter by typically two orders of magnitude. The observed gas distribution throughout the nearby M81 group of galaxies shows evidence for past significant galaxy-galaxy interactions but without a merger having occurred. This group is here studied for possible dynamical solutions within the dark-matter standard model. In order to cover a comprehensive set of initial conditions, the inner three core members M81, M82 and NGC 3077 are treated as a three-body model based on Navarro-Frenk-White profiles. The possible orbits of these galaxies are examined statistically taking into account dynamical friction. Long living, non-merging initial constellations which allow multiple galaxy-galaxy encounters comprise unbound galaxies only, which are arriving from a far distance and happen to simultaneously encounter each other within the recent 500 Myr. Our results are derived by the employment of two separate and independent statistical methods, namely a Markov chain Monte Carlo method and the genetic algorithm using the SAP system environment. The conclusions reached are confirmed by high-resolution simulations of live self-consistent systems (N-body calculations). Given the observed positions of the three galaxies the solutions found comprise predictions for their proper motions.

  17. How intragroup dynamics affect behavior in intergroup conflict: the role of group norms, prototypicality, and need to belong

    NARCIS (Netherlands)

    Steinel, W.; van Kleef, G.A.; van Knippenberg, D.; Hogg, M.A.; Homan, A.C.; Moffit, G.

    2010-01-01

    This study explores the role of intragroup dynamics in intergroup conflict. In a computer-mediated negotiation experiment (N = 107), we investigated how a group representative’s standing in the group, group norm, and the representative’s need to belong influence behavior in intergroup negotiations.

  18. 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.

  19. 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.

  20. 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.

  1. HIERARCHICAL ACCESS CONTROL IN DYNAMIC PEER GROUPS USING SYMMETRIC POLYNOMIAL AND TREE BASED GROUP ELLIPTIC CURVE DIFFIE HELLMAN SCHEME

    Directory of Open Access Journals (Sweden)

    Nafeesa Begum Jeddy

    2014-01-01

    Full Text Available Hierarchical Access Control in group communication is an active area of research which is difficult to achieve it. Its primary objective is to allow users of a higher authority group to access information or resource held by lower group users and preventing the lower group users to access information held by higher class users. Large collection of collaborative applications in organizations inherently has hierarchical structures for functioning, where providing security by efficient group key management is a big challenging issue. While preserving centralized methods for hierarchical access control, it is difficult to achieve efficiency as a single membership change will result in lot of changes which are difficult to maintain. So, using distributed key agreement techniques is more appropriate for this scenario. This study explore on novel group key agreement approach, which combines both the symmetric polynomial scheme and Tree Based Group elliptic Curve key exchange. Also, it yields a secure protocol suite that is good in fault-tolerant and simple. The efficiency of SP-TGECDH is better than many other schemes. Using TGECDH makes the scheme suitable small Low powered devices.

  2. 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.

  3. 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.

  4. Many-body localization in one dimension as a dynamical renormalization group fixed point.

    Science.gov (United States)

    Vosk, Ronen; Altman, Ehud

    2013-02-08

    We formulate a dynamical real space renormalization group (RG) approach to describe the time evolution of a random spin-1/2 chain, or interacting fermions, initialized in a state with fixed particle positions. Within this approach we identify a many-body localized state of the chain as a dynamical infinite randomness fixed point. Near this fixed point our method becomes asymptotically exact, allowing analytic calculation of time dependent quantities. In particular, we explain the striking universal features in the growth of the entanglement seen in recent numerical simulations: unbounded logarithmic growth delayed by a time inversely proportional to the interaction strength. This is in striking contrast to the much slower entropy growth as loglogt found for noninteracting fermions with bond disorder. Nonetheless, even the interacting system does not thermalize in the long time limit. We attribute this to an infinite set of approximate integrals of motion revealed in the course of the RG flow, which become asymptotically exact conservation laws at the fixed point. Hence we identify the many-body localized state with an emergent generalized Gibbs ensemble.

  5. 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.

  6. Dynamics of Social Group Competition: Modeling the Decline of Religious Affiliation

    Science.gov (United States)

    Abrams, Daniel M.; Yaple, Haley A.; Wiener, Richard J.

    2011-08-01

    When social groups compete for members, the resulting dynamics may be understandable with mathematical models. We demonstrate that a simple ordinary differential equation (ODE) model is a good fit for religious shift by comparing it to a new international data set tracking religious nonaffiliation. We then generalize the model to include the possibility of nontrivial social interaction networks and examine the limiting case of a continuous system. Analytical and numerical predictions of this generalized system, which is robust to polarizing perturbations, match those of the original ODE model and justify its agreement with real-world data. The resulting predictions highlight possible causes of social shift and suggest future lines of research in both physics and sociology.

  7. Renormalization group improvement and dynamical breaking of symmetry in a supersymmetric Chern-Simons-matter model

    Science.gov (United States)

    Quinto, A. G.; Ferrari, A. F.; Lehum, A. C.

    2016-06-01

    In this work, we investigate the consequences of the Renormalization Group Equation (RGE) in the determination of the effective superpotential and the study of Dynamical Symmetry Breaking (DSB) in an N = 1 supersymmetric theory including an Abelian Chern-Simons superfield coupled to N scalar superfields in (2 + 1) dimensional spacetime. The classical Lagrangian presents scale invariance, which is broken by radiative corrections to the effective superpotential. We calculate the effective superpotential up to two-loops by using the RGE and the beta functions and anomalous dimensions known in the literature. We then show how the RGE can be used to improve this calculation, by summing up properly defined series of leading logs (LL), next-to-leading logs (NLL) contributions, and so on... We conclude that even if the RGE improvement procedure can indeed be applied in a supersymmetric model, the effects of the consideration of the RGE are not so dramatic as it happens in the non-supersymmetric case.

  8. FLOCKING OF MULTI-AGENT DYNAMIC SYSTEMS WITH GUARANTEED GROUP CONNECTIVITY

    Institute of Scientific and Technical Information of China (English)

    Xiaoli LI; Yugeng XI

    2008-01-01

    This paper investigates distributed flocking problem where the information exchange among agents is modeled by the communication topology changing with time. Previous research on this problem establishes group stabilization by assuming that the dynamic topology is connected all the time, which however cannot be guaranteed by most proposed distributed control laws. In this paper, a distributed algorithm to distill a necessary subgraph of the initial communication topology is presented.This subgraph covers all the vertices of the communication topology and is proved to be connected as long as the initial communication topology is connected. A distributed control law is then designed to pursue the flocking motion while preserving all the edges in this subgraph. In this way, connectivity can be preserved all the time, and flocking problem is thus solved only provided the initial communication topology of multi-agent system is connected.

  9. Effect of group walking traffic on dynamic properties of pedestrian structures

    Science.gov (United States)

    Shahabpoor, E.; Pavic, A.; Racic, V.; Zivanovic, S.

    2017-01-01

    The increasing number of reported vibration serviceability problems in newly built pedestrian structures, such as footbridges and floors, under walking load has attracted considerable attention in the civil engineering community over the past two decades. The key design challenges are: the inter- and intra-subject variability of walking people, the unknown mechanisms of their interaction with the vibrating walking surfaces and the synchronisation between individuals in a group. Ignoring all or some of these factors makes the current design methods an inconsistent approximation of reality. This often leads to considerable over- or under-estimation of the structural response, yielding an unreliable assessment of vibration performance. Changes to the dynamic properties of an empty structure due to the presence of stationary people have been studied extensively over the past two decades. The understanding of the similar effect of walking people on laterally swaying bridges has improved tremendously in the past decade, due to considerable research prompted by the Millennium Bridge problem. However, there is currently a gap in knowledge about how moving pedestrians affect the dynamic properties of vertically vibrating structures. The key reason for this gap is the scarcity of credible experimental data pertinent to moving pedestrians on vertically vibrating structures, especially for multi-pedestrian traffic. This paper addresses this problem by studying the dynamic properties of the combined human-structure system, i.e. occupied structure damping ratio, natural frequency and modal mass. This was achieved using a comprehensive set of frequency response function records, measured on a full-scale test structure, which was occupied by various numbers of moving pedestrians under different walking scenarios. Contrary to expectations, it was found that the natural frequency of the joint moving human-structure system was higher than that of the empty structure, while it was

  10. 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.

  11. Structural model of in-group dynamic of 6-10 years old boys’ motor fitness

    Directory of Open Access Journals (Sweden)

    Ivashchenko O.V.

    2015-10-01

    Full Text Available Purpose: to determine structural model of in-group dynamic of 6-10 years old boys’ motor fitness. Material: in the research 6 years old boys (n=48, 7 years old (n=45, 8 years old (n=60, 9 years’ age (n=47 and10 years’ age (n=40 participated. We carried out analysis of factorial model of schoolchildren’s motor fitness. Results: we received information for taking decisions in monitoring of physical education. This information is also necessary for working out of effective programs of children’s and adolescents’ physical training. We determined model of motor fitness and specified informative tests for pedagogic control in every age group. In factorial model of boys’ motor fitness the following factor is the most significant: for 6 years - complex development of motor skills; for 7 years - also complex development of motor skills; for 8 years - strength and coordination; for 9 years - complex development of motor skills; for 10 years - complex development of motor skills. Conclusions: In factorial model of 6-10 years old boys’ motor fitness the most significant are backbone and shoulder joints’ mobility, complex manifestation of motor skills, motor coordination. The most informative tests for assessment of different age boys’ motor fitness have been determined.

  12. A Dynamically Driven, Universal Thermal Profile of Galaxy Groups and Clusters

    CERN Document Server

    Reiss, Ido

    2014-01-01

    Groups and clusters of galaxies show a universal, nearly linear entropy radial profile $K(r)$. Using deprojected 13 clusters and 9 groups from the literature, we find that $K(r)\\propto r^{0.97\\pm0.01}$, consistent with the mean power-law index $\\sim(0.9-1.1)$ of previous studies. An equally good fit to the data is given by a $(t_{cool}/t_{ff})\\propto r^{0.73\\pm0.01}$ ratio between cooling and free-fall times. Both profiles slightly flatten at small radii, as $(t_{cool}/t_{ff})$ becomes of order unity. The entropy profile is usually attributed to the primordial gas crossing the virial shock, to non-standard heat conduction, or to turbulent heating. We argue that a dynamical mechanism is needed to sustain such a simple profile, oblivious to the temperature peak at the edge of the core and to the virial shock at the outskirts, and robust to the presence of ongoing cooling, merger, and AGN activity. In particular, we show that such a profile is naturally obtained in a spiral flow, which is likely to exist in most...

  13. Psychological changes and group dynamics during confinement in an isolated environment.

    Science.gov (United States)

    Kraft, Norbert O; Inoue, Natsuhiko; Mizuno, Koh; Ohshima, Hiroshi; Murai, Tadashi; Sekiguchi, Chiharu

    2002-02-01

    Cultural and personal traits will become important as the number of short-duration spaceflights of international crews supporting the International Space Station (ISS) increases and more people begin staying aboard ISS for longer durations. This project investigated the interpersonal and personal changes of Japanese subjects during a 1-wk stay in the Japanese Experiment Module. The Giebetaen Test (GT) was used to determine if the cultural background and personality traits of the subjects become more explicit and stronger during isolation. Six males and two females aged 22-28 yr participated in the study. They stayed 7 d in the isolation chamber at the National Space Development Agency of Japan (NASDA). The GT was chosen as an individual and group diagnostic instrument; it was administrated four times during, and one time after, isolation. According to the GT-self-picture, subjects exhibited a change toward negative social resonance and social withdrawal. Subgroups formed but caused no isolation or tension. The GT-foreign-pictures showed that the judgment of other subjects changed toward hedonic and permeability directions. The common interpersonal relationships of the Japanese subjects influenced the group dynamics. These relationships tend to be integrative and tend to support the network and value systems, emphasizing connectedness and minimizing differences. The cultural background became more explicit and stronger during isolation. Based on this, isolation studies with international crews and intercultural training will be necessary for international crews performing both short- and long-duration missions.

  14. 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

  15. 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.

  16. 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.)

  17. Dynamic renormalization group study of a generalized continuum model of crystalline surfaces.

    Science.gov (United States)

    Cuerno, Rodolfo; Moro, Esteban

    2002-01-01

    We apply the Nozières-Gallet dynamic renormalization group (RG) scheme to a continuum equilibrium model of a d-dimensional surface relaxing by linear surface tension and linear surface diffusion, and which is subject to a lattice potential favoring discrete values of the height variable. The model thus interpolates between the overdamped sine-Gordon model and a related continuum model of crystalline tensionless surfaces. The RG flow predicts the existence of an equilibrium roughening transition only for d=2 dimensional surfaces, between a flat low-temperature phase and a rough high-temperature phase in the Edwards-Wilkinson (EW) universality class. The surface is always in the flat phase for any other substrate dimensions d>2. For any value of d, the linear surface diffusion mechanism is an irrelevant perturbation of the linear surface tension mechanism, but may induce long crossovers within which the scaling properties of the linear molecular-beam epitaxy equation are observed, thus increasing the value of the sine-Gordon roughening temperature. This phenomenon originates in the nonlinear lattice potential, and is seen to occur even in the absence of a bare surface tension term. An important consequence of this is that a crystalline tensionless surface is asymptotically described at high temperatures by the EW universality class.

  18. 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.

  19. 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. Keywords: Sociocultural theory; dynamic assessment; group dynamic assessment; zone of proximal development; interaction

  20. 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

  1. Dynamical decimation renormalization-group technique: kinetic gaussian model on nonbranching, branching, and multibranching koch curves

    Science.gov (United States)

    Zhu; Yang

    2000-06-01

    A generalizing formulation of dynamical real-space renormalization that is appropriate for arbitrary spin systems is suggested. The alternative version replaces single-spin flipping Glauber dynamics with single-spin transition dynamics. As an application, in this paper we mainly investigate the critical slowing down of the Gaussian spin model on three fractal lattices, including nonbranching, branching, and multibranching Koch curves. The dynamical critical exponent z is calculated for these lattices using an exact decimation renormalization transformation in the assumption of the magneticlike perturbation, and a universal result z=1/nu is found.

  2. Interactions between grain boundary faceting, migration and grain rotation: Color group and molecular dynamics simulation approaches

    Science.gov (United States)

    Huang, Yue

    Color group theory and molecular dynamics (MD) simulations were used to study the faceting and rotation of grains in nanocrystalline materials and their interactions. Color group arguments were used to determine symmetry-dictated extrema with respect to misorientation of the grains and with respect to grain boundary normal orientations. MD simulations were used to study the evolution of the system and to elucidate the interactions between grain rotation and faceting in nano-scale systems. The systems of study were fcc bicrystalline systems with two grains sharing their [110] directions. Two geometric parameters were studied: the misorientation between two grains with a common rotation axis in the [110] direction of both grains, and the grain boundary normal orientation of fcc (110) tilt grain boundaries. The symmetry-dictated extremum (SDE) with respect to misorientation around both grains' [110] direction is 90 degrees. The SDE with respect to GB normal orientations for (110) tilt GBs are located on top of the color and classical mirror planes of their dichromatic patterns. By using periodic boundary conditions and a cylindrical embedded grain structure in our simulations, grains are only free to vary the misorientation between grains around the common [110] direction, and the normal of the grain boundaries are always perpendicular to both grains [110] direction. All SDE studied in our simulation are observed to be local energy minimum states. We observed the systems reducing their excess energy through three main modes: forming facets at the boundaries, rotating between the two grains, and reduction of grain boundary area through grain shrinkage. Facets are formed in low-energy grain boundaries and oscillating rotation occurred when the initial misorientation was not a SDE. A new algorithm was developed to quantitatively measure the grain rotation. The ovsered rotations are not rigid-body rotations and have strong interaction with faceting. Systems with lower

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

    Energy Technology Data Exchange (ETDEWEB)

    Axinescu, S.; Bartolini, R.; Bazzani, A.; Biagini, M.; Chao, A.; Dragt, A.; Ellison, J.; Faus-Golfe, A.; Freguglia, P.; Hirata, K.; Ng, K.; Oide, K.; Ritson, D.; Schmidt, F.; Scandale, W.; Tazzari, S.; Todesco, E.; Turchetti, G.; Verolino, L.; Wan, W.; Warnock, R.; Yan, Y.

    1997-02-01

    This is a summary of the topics covered on the single particle nonlinear dynamics of particle accelerators. In particular, discussions of calculation tools for analysis of beams in accelerators, current status of understanding the dynamics aperture, and the problem of ripple, effects have been given. {copyright} {ital 1997 American Institute of Physics.}

  4. 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.

  5. Revisiting Group-Based Technology Adoption as a Dynamic Process: The Role of Changing Attitude-Rationale Configurations.

    NARCIS (Netherlands)

    Bayerl, P.S.; Lauche, K.; Axtell, C.

    2016-01-01

    In this study, we set out to better understand the dynamics behind group-based technology adoption by nvestigating the underlying mechanisms of changes in collective adoption decisions over time. Using a longitudinal multi-case study of production teams in the British oil and gas industry, we outli

  6. "Stop and Go": In Search of New Ecology and Dynamics in Group Counselling for Employees in Transition

    Science.gov (United States)

    Keskinen, Anita; Spangar, Timo

    2013-01-01

    "Stop and Go" (SG) is a group counselling concept developed for employees in transition. The SG approach has its main roots in relational psychology. This article explores the ecology and the dynamics of the SG process including the simultaneous presence of societal and social ('meso') factors, as well as the individual…

  7. Revisiting group-based technology adoption as a dynamic process: The role of changing attitude-rationale configurations.

    NARCIS (Netherlands)

    Bayerl, P.S.; Lauche, K.; Axtell, C.

    2016-01-01

    In this study, we set out to better understand the dynamics behind group-based technology adoption by nvestigating the underlying mechanisms of changes in collective adoption decisions over time. Using a longitudinal multi-case study of production teams in the British oil and gas industry, we

  8. Revisiting group-based technology adoption as a dynamic process: The role of changing attitude-rationale configurations

    NARCIS (Netherlands)

    P.S. Bayerl (Saskia); K. Lauche (Kristina); Axtell, C. (Carolyn)

    2016-01-01

    textabstractIn this study, we set out to better understand the dynamics behind group-based technology adoption by investigating the underlying mechanisms of changes in collective adoption decisions over time. Using a longitudinal multi-case study of production teams in the British oil and gas

  9. Nonequilibrium dynamics of random field Ising spin chains: exact results via real space renormalization group.

    Science.gov (United States)

    Fisher, D S; Le Doussal, P; Monthus, C

    2001-12-01

    The nonequilibrium dynamics of classical random Ising spin chains with nonconserved magnetization are studied using an asymptotically exact real space renormalization group (RSRG). We focus on random field Ising model (RFIM) spin chains with and without a uniform applied field, as well as on Ising spin glass chains in an applied field. For the RFIM we consider a universal regime where the random field and the temperature are both much smaller than the exchange coupling. In this regime, the Imry-Ma length that sets the scale of the equilibrium correlations is large and the coarsening of domains from random initial conditions (e.g., a quench from high temperature) occurs over a wide range of length scales. The two types of domain walls that occur diffuse in opposite random potentials, of the form studied by Sinai, and domain walls annihilate when they meet. Using the RSRG we compute many universal asymptotic properties of both the nonequilibrium dynamics and the equilibrium limit. We find that the configurations of the domain walls converge rapidly toward a set of system-specific time-dependent positions that are independent of the initial conditions. Thus the behavior of this nonequilibrium system is pseudodeterministic at long times because of the broad distributions of barriers that occur on the long length scales involved. Specifically, we obtain the time dependence of the energy, the magnetization, and the distribution of domain sizes (found to be statistically independent). The equilibrium limits agree with known exact results. We obtain the exact scaling form of the two-point equal time correlation function and the two-time autocorrelations . We also compute the persistence properties of a single spin, of local magnetization, and of domains. The analogous quantities for the +/-J Ising spin glass in an applied field are obtained from the RFIM via a gauge transformation. In addition to these we compute the two-point two-time correlation function which can in

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

    Energy Technology Data Exchange (ETDEWEB)

    Chattopadhyay, S.; Audy, P.; Courant, E.D.; Forest, E.; Guignard, G.; Hagel, J.; Heifets, S.; Keil, E.; Kheifets, S.; Mais, H.; Moshammer, H.; Pellegrini, C.; Pilat, F.; Suzuki, T.; Turchetti, G.; Warnock, R.L.

    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.

  11. Group comparison of spatiotemporal dynamics of intrinsic networks in Parkinson's disease.

    Science.gov (United States)

    Madhyastha, Tara M; Askren, Mary K; Zhang, Jing; Leverenz, James B; Montine, Thomas J; Grabowski, Thomas J

    2015-09-01

    Recent advances with functional connectivity magnetic resonance imaging have demonstrated that at rest the brain exhibits coherent activity within a number of spatially independent maps, normally called 'intrinsic' or 'resting state' networks. These networks support cognition and behaviour, and are altered in neurodegenerative disease. However, there is a longstanding perspective, and ample functional magnetic resonance imaging evidence, demonstrating that intrinsic networks may be fractionated and that cortical elements may participate in multiple intrinsic networks at different times, dynamically changing alliances to adapt to cognitive demands. A method to probe the fine-grained spatiotemporal structure of networks may be more sensitive to subtle network changes that accompany heterogeneous cognitive deficits caused by a neurodegenerative disease such as Parkinson's disease. Here we tested the hypothesis that alterations to the latent (hidden) structure of intrinsic networks may reveal the impact of underlying pathophysiologic processes as assessed with cerebrospinal fluid biomarkers. Using a novel modelling approach that we call 'network kernel analysis', we compared fine-grained network ensembles (network kernels) that include overlapping cortical elements in 24 patients with Parkinson's disease (ages 45-86, 17 male) and normal cognition or mild cognitive impairment (n = 13), and 21 cognitively normal control subjects (ages 41-76, nine male). An omnibus measure of network disruption, calculated from correlations among network kernels, was correlated with cerebrospinal fluid biomarkers of pathophysiological processes in Parkinson's disease: concentrations of α-synuclein and amyloid-β42. Correlations among network kernels more accurately classified Parkinson's disease from controls than other functional neuroimaging measures. Inspection of the spatial maps related to the default mode network and a frontoparietal task control network kernel showed that the

  12. The Essence Of Group Dynamics In Miss Brodie’s Classroom

    OpenAIRE

    Kızılaslan, Dr. İrem

    2013-01-01

    This paper investigates the nature of social groups considering how the mere need to belong affects behavior Next it discusses some of the basic processes of interaction in small cohesive groups including social norms and social roles conformity versus non conformity group mentality and group decision making with examples from the novel The Prime of Miss Jean Brodie 1961 by Muriel Spark This ground breaking work of Spark concerns an eccentric but charismatic teacher who creates a pote...

  13. Study on group air to ground attack-defends hierarchical dynamic decision-making

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    As to oppositional,multi-objective and hierarchical characteristic of air formation to ground attack-defends campaign,and using dynamic space state model of military campaign,this article establishes a principal and subordinate hierarchical interactive decision-making way,the Nash-Stackelberg-Nash model,to solve the problems in military operation,and find out the associated best strategy in hierarchical dynamic decision-making.The simulating result indicate that when applying the model to air formation to ground attack-defends decision-making system,it can solve the problems of two hierarchies'dynamic oppositional decision-making favorably,and reach preferable effect in battle.It proves that the model can provide an effective way for analyzing a battle.

  14. Dynamical real-space renormalization group calculations with a highly connected clustering scheme on disordered networks.

    Science.gov (United States)

    Balcan, D; Erzan, A

    2005-02-01

    We have defined a type of clustering scheme preserving the connectivity of the nodes in a network, ignored by the conventional Migdal-Kadanoff bond moving process. In high dimensions, our clustering scheme performs better for correlation length and dynamical critical exponents than the conventional Migdal-Kadanoff bond moving scheme. In two and three dimensions we find the dynamical critical exponents for the kinetic Ising model to be z=2.13 and z=2.09 , respectively, at the pure Ising fixed point. These values are in very good agreement with recent Monte Carlo results. We investigate the phase diagram and the critical behavior of randomly bond diluted lattices in d=2 and 3 in the light of this transformation. We also provide exact correlation exponent and dynamical critical exponent values on hierarchical lattices with power-law and Poissonian degree distributions.

  15. Dynamics of the OH group and the electronic structure of liquid alcohols

    Directory of Open Access Journals (Sweden)

    Simon Schreck

    2014-09-01

    Full Text Available In resonant inelastic soft x-ray scattering (RIXS from molecular and liquid systems, the interplay of ground state structural and core-excited state dynamical contributions leads to complex spectral shapes that partially allow for ambiguous interpretations. In this work, we dissect these contributions in oxygen K-edge RIXS from liquid alcohols. We use the scattering into the electronic ground state as an accurate measure of nuclear dynamics in the intermediate core-excited state of the RIXS process. We determine the characteristic time in the core-excited state until nuclear dynamics give a measurable contribution to the RIXS spectral profiles to τdyn = 1.2 ± 0.8 fs. By detuning the excitation energy below the absorption resonance we reduce the effective scattering time below τdyn, and hence suppress these dynamical contributions to a minimum. From the corresponding RIXS spectra of liquid methanol, we retrieve the “dynamic-free” density of states and find that it is described solely by the electronic states of the free methanol molecule. From this and from the comparison of normal and deuterated methanol, we conclude that the split peak structure found in the lone-pair emission region at non-resonant excitation originates from dynamics in the O–H bond in the core-excited state. We find no evidence that this split peak feature is a signature of distinct ground state structural complexes in liquid methanol. However, we demonstrate how changes in the hydrogen bond coordination within the series of linear alcohols from methanol to hexanol affect the split peak structure in the liquid alcohols.

  16. How Can Social Psychology and Group Dynamics Assist in Curriculum Development?

    Science.gov (United States)

    Chin, Jeffrey; May, Matthew; Sullivan-Chin, Honora; Woodrick, Kaylyn

    2014-01-01

    This article discusses some of the challenges departments face as they embark on curriculum development. The interpersonal dynamics of a department are often the first and most difficult obstacle to overcome but are often overlooked. The author suggests some strategies for how to address these issues as they arise.

  17. How Can Social Psychology and Group Dynamics Assist in Curriculum Development?

    Science.gov (United States)

    Chin, Jeffrey; May, Matthew; Sullivan-Chin, Honora; Woodrick, Kaylyn

    2014-01-01

    This article discusses some of the challenges departments face as they embark on curriculum development. The interpersonal dynamics of a department are often the first and most difficult obstacle to overcome but are often overlooked. The author suggests some strategies for how to address these issues as they arise.

  18. The Dynamic Terrorist Threat: An Assessment of Group Motivations and Capabilities in a Changing World

    Science.gov (United States)

    2004-01-01

    reconnaissance, with a team sent to survey, plan, and prepare for the attack with help from local dissi- ______________ 104“El Silencio de las Armas...Ha’aretz, June 21, 2001. 104 The Dynamic Terrorist Threat “El Silencio de las Armas,” Cambio, August 14, 2000. Sobelman, Daniel, “Hizbullah Lends Its

  19. Centrifuge model test on dynamic behavior of group-pile foundation With inclined piles and its numerical simulation

    Institute of Scientific and Technical Information of China (English)

    Feng ZHANG; Katsunori OKAWA; Makoto KIMURA

    2008-01-01

    In this paper, dynamic behavior of a grouppile foundation with inclined piles in loose sand has been investigated with centrifuge model tests. The test results are also simulated with elastoplastic dynamic finite ele-ment method, in which, not only sectional force of piles, stress of ground, but also deformation of piles are calcu-lated using a three-dimensional elastoplastic dynamic finite element analysis (Code name: DGPILE-3D). The numerical analyses are conducted with a full system in which a superstructure, a pile foundation and surround-ing ground are considered together so that interaction between pile foundation and soils can be properly simu-lated because the nonlinearities of both the pile and the ground are described with suitable constitutive models. Different types of piles, vertical pile or inclined pile, are considered in order to verify the different characteristics of a group pile foundation with inclined piles. The validity of the calculation is verified by the model tests.

  20. 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.

  1. 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.

  2. Dynamic response of a laterally loaded fixed-head pile group in a transversely isotropic multilayered half-space

    Science.gov (United States)

    Ai, Zhi Yong; Li, Zhi Xiong; Wang, Li Hua

    2016-12-01

    The time-harmonic response of a laterally loaded fixed-head pile group embedded in a transversely isotropic multilayered half-space is investigated using a finite element and indirect boundary element coupling method. The piles are solved by the finite element method (FEM), while the soil can be modeled by the indirect boundary element method (BEM) with the aid of the fundamental solution for a transversely isotropic multilayered half-space in a cylindrical coordinate system. The governing equation of the pile-soil-pile dynamic interaction is established by applying the FEM-BEM coupling method. Numerical examples are carried out to validate the presented theory and to investigate influences of the soil's anisotropy and layering on the dynamic response of pile groups.

  3. 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.

  4. 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.

  5. The impacts of hypnotic susceptibility on chaotic dynamics of EEG signals during standard tasks of Waterloo-Stanford Group Scale.

    Science.gov (United States)

    Yargholi, Elahe'; Nasrabadi, Ali Motie

    2013-05-01

    Chaotic features of hypnotic EEG (electroencephalograph), recorded during standard tasks of Waterloo-Stanford Group Scale of hypnotic susceptibility (WSGS), were used to investigate the underlying dynamic of tasks and analyse the effect of hypnotic depth and concentration on EEG signals. Results demonstrate: (1) More efficiency of Higuchi dimension in comparison with Correlation dimension to distinguish subjects from different hypnotizable groups, (2) Channels with significantly different chaotic features among people from various hypnotizability levels in tasks, (3) High level of consistency among discriminating channels of tasks with function of brain's lobes, (4) Most affectability of medium hypnotizable subjects and (5) Rise in fractal dimensions due to increase in hypnosis depth.

  6. 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...... fields from the allospatial state. The allostate in turn is excited from space by the momentum operators which act as toroidal generators on the group manifold. Such generators can be used to trace out parton distribution functions and examples are shown to mimic the valence quark content of the proton....

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

    Institute of Scientific and Technical Information of China (English)

    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 multigroup 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 R0 is derived and the global dynamics of the model are established.It is shown that if R0 is less than or equal to 1,the disease-free equilibrium is globally asymptotically stable and the worm dies out eventually,whereas,if R0 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.

  8. BoD services in layer 1 VPN with dynamic virtual concatenation group

    Science.gov (United States)

    Du, Shu; Peng, Yunfeng; Long, Keping

    2008-11-01

    Bandwidth-on-Demand (BoD) services are characteristic of dynamic bandwidth provisioning based on customers' resource requirement, which will be a must for future networks. BoD services become possible with the development of make-before-break, Virtual Concatenation (VCAT) and Link Capacity Adjustment Scheme (LCAS). In this paper, we introduce BoD services into L1VPN, thus the resource assigned to a L1VPN can be gracefully adjusted at various bandwidth granularities based on customers' requirement. And we propose a dynamic bandwidth adjustment scheme, which is compromise between make-before-break and VCAT&LCAS and mainly based on the latter. The scheme minimizes the number of distinct paths to support a connection between a source-destination pair, and uses make-beforebreak technology for re-optimization.

  9. Identification of dynamic forces using group-sparsity in frequency domain

    Science.gov (United States)

    Rezayat, A.; Nassiri, V.; De Pauw, B.; Ertveldt, J.; Vanlanduit, S.; Guillaume, P.

    2016-03-01

    The knowledge of acting dynamic forces is required for the design of structures. Given the structural model, inverse techniques offer the possibility to reconstruct the system's input forces from vibration data. The inverse problem is highly sensitive to measurement noise, and the classical pseudo-inverse method generally fails to find the correct loads. In this paper we propose a new penalty function that combines the advantages of the ℓp-norm properties, together with a modified iterative optimization technique. The new algorithm (G-FISTA) is used to localize and reconstruct dynamic point-forces on a beam structure, with no prior knowledge on the force locations. The algorithm is validated by means of several simulations and experiments. The strain data is measured using Fiber Bragg Gratings (FBG) attached to the beam. The obtained results show that the location and time history of point forces are better estimated using the proposed technique.

  10. Dynamics of hormonal status in women of different age groups in hemorrhagic fever with renal syndrome

    Directory of Open Access Journals (Sweden)

    Murzabaeva R.Т.

    2012-06-01

    Full Text Available Objective: To study the hormonal parameters in women of different age groups in hemorrhagic fever with renal syndrome. Materials and methods: We have studied the content of cortisol, thyrotropic hormone (TTH, triiodothyro-nine (T3, free thyroxin (FT4, luteinizing hormone (LH, follicle-stimulating hormone (FSH, testosterone, estradiol, progesterone, prolactin in blood serum of 62 women with moderate (33 and severe (29 HFRS forms age (17-62. They were divided into 2 groups: the first group (33 patients women with the normal menstrual cycle, the second group (29 women consisted of patients in climacteric period. Results: TTH secretion increase, T3 and FT4 — decrease with their normalization to the recovery period were registered in the thyroid system of the compared groups. Blood cortisol level was high during the illness. Gonadotropic hypophysis function study demonstrated that LH and blood prolactin concentrations were increased since oliguria period; FSH was authentic reduced. The indices of these hormones were restored to the normal level by the reconvalescence period. LH and FSH contents were authentic higher in women of the second group in comparison with the first group. The hyperprolactinemia was observed in both women groups during the whole period of disease. The increased progesterone and testosterone concentrations have been manifested in blood serum. The estradiol concentration had different direction tendencies. Conclusion: Thus, the complex study of hypophysic- thyreoid and gonadotropic hormone state of adrenal system and the sexual hormone levels in women of different age groups in HFRS revealed the hormone status indces changes due to the period and severity of the disease, connected with the virus action, intoxication, the general inflammation reactions and their age.

  11. Efficient Dynamic Threshold Group Signature Scheme Based on Elliptic Curve Cryptosystem

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The short secret key characteristic of elliptic curve cryptosystem (ECC) are integrated with the (t,n ) threshold method to create a practical threshold group signature scheme characterized by simultaneous signing. The scheme not only meets the requirements of anonymity and traceability of group signature but also can withstand Tseng and Wangs conspiracy attack. It allows the group manager to add new members and delete old members according to actual application, while the system parameters have a little change. Cryptanalysis result shows that the scheme is efficient and secure.

  12. 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...... 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...

  13. Group Threat and Policy Change: The Spatial Dynamics of Prohibition Politics, 1890-1919.

    Science.gov (United States)

    Andrews, Kenneth T; Seguin, Charles

    2015-09-01

    The authors argue that group threat is a key driver of the adoption of new and controversial policies. Conceptualizing threat in spatial terms, they argue that group threat is activated through the joint occurrence of (1) proximity to threatening groups and (2) the population density of threatened groups. By analyzing the adoption of county and state "dry laws" banning alcohol from 1890 to 1919, they first show that prohibition victories were driven by the relative strength of supportive constituencies such as native whites and rural residents, vis-à-vis opponents such as Irish, Italian, or German immigrants or Catholics. Second, they show that threat contributed to prohibition victories: counties bordering large immigrant or urban populations, which did not themselves contain similar populations, were more likely to adopt dry laws. Threat arises primarily from interactions between spatially proximate units at the local level, and therefore higher-level policy change is not reducible to the variables driving local policy.

  14. Basic Science of the Fundamentals and Dynamics of Social-Fringe Group Formation and Sustainment

    Science.gov (United States)

    2012-08-01

    Counseling Psychology Ph ilosophy (3) Mathemancs Human Fact ors (2) Civil Engineering Secondary Political Science (2) Religious St udies ... Mexico , S. Korea). Study of Social Fringe Group Formation Processes: Crystallization vs. Transformation This proposes to use case study analysis to

  15. 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

  16. 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.

  17. How group size affects vigilance dynamics and time allocation patterns: the key role of imitation and tempo.

    Directory of Open Access Journals (Sweden)

    Pablo Michelena

    Full Text Available In the context of social foraging, predator detection has been the subject of numerous studies, which acknowledge the adaptive response of the individual to the trade-off between feeding and vigilance. Typically, animals gain energy by increasing their feeding time and decreasing their vigilance effort with increasing group size, without increasing their risk of predation ('group size effect'. Research on the biological utility of vigilance has prevailed over considerations of the mechanistic rules that link individual decisions to group behavior. With sheep as a model species, we identified how the behaviors of conspecifics affect the individual decisions to switch activity. We highlight a simple mechanism whereby the group size effect on collective vigilance dynamics is shaped by two key features: the magnitude of social amplification and intrinsic differences between foraging and scanning bout durations. Our results highlight a positive correlation between the duration of scanning and foraging bouts at the level of the group. This finding reveals the existence of groups with high and low rates of transition between activities, suggesting individual variations in the transition rate, or 'tempo'. We present a mathematical model based on behavioral rules derived from experiments. Our theoretical predictions show that the system is robust in respect to variations in the propensity to imitate scanning and foraging, yet flexible in respect to differences in the duration of activity bouts. The model shows how individual decisions contribute to collective behavior patterns and how the group, in turn, facilitates individual-level adaptive responses.

  18. Utility Rate Equations of Group Population Dynamics in Biological and Social Systems

    CERN Document Server

    Yukalov, V I; Sornette, D

    2014-01-01

    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 10% 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 q...

  19. 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.

  20. Time Development of Early Social Networks: Link analysis and group dynamics

    CERN Document Server

    Bruun, Jesper

    2013-01-01

    Empirical data on early network history are rare. Students beginning their studies at a university with no or few prior connections to each other offer a unique opportunity to investigate the formation and early development of 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. These networks have also been investigated to elucidate possible effects of gender and students' final course grade. Changes in the weekly number of links are investigated to 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. To investigate how students group, Infomap is used to establish groups. Further, student group flow is examined using alluvial diagrams, showing th...

  1. Dynamics of telomere length in different age groups in a Latvian population.

    Science.gov (United States)

    Zole, Egija; Pliss, Liana; Ranka, Renate; Krumina, Astrida; Baumanis, Viesturs

    2013-12-01

    The shortening of telomeres with ageing is a well-documented observation; however, the reported number of nucleotides in telomeres varies between different laboratories and studies. Such variability is likely caused by ethnic differences between the populations studied. Until now, there were no studies that investigated the variability of telomere length in a senescent Latvian population of the most common mitochondrial haplogroups, defined as H (45%), U (25%), Y chromosomal N1c (40%) and R1a1 (40%). Telomere length was determined in 121 individuals in different age groups, including a control group containing individuals of 20-40 years old and groups of individuals between 60-70 years old, 71-80 years old, 81-90 years old, and above 90 years old. Telomere length was determined using the Southern blot telomeric restriction fragment assay (TRF). Decreased telomere length with ageing was confirmed, but a comparison of centenarians and individuals between 60-90 years of age did not demonstrate a significant difference in telomere length. However, significant variability in telomere length was observed in the control group, indicating probable rapid telomere shortening in some individuals that could lead up to development of health status decline appearing with ageing. Telomere length measured in mononuclear blood cells (MNC) was compared with the telomere length measured in whole peripheral white blood cells (WBC) using TRF. Telomere length in MNC was longer than in WBC for the control group with individuals 20 to 40 years old; in contrast, for the group of individuals aged 65 to 85 years old, measured telomere length was shorter in MNC when compared to WBC.

  2. Behavioral suites mediate group-level foraging dynamics in communities of tropical stingless bees.

    Science.gov (United States)

    Lichtenberg, E M; Imperatriz-Fonseca, V L; Nieh, J C

    2010-02-01

    Competition for floral resources is a key force shaping pollinator communities, particularly among social bees. The ability of social bees to recruit nestmates for group foraging is hypothesized to be a major factor in their ability to dominate rich resources such as mass-flowering trees. We tested the role of group foraging in attaining dominance by stingless bees, eusocial tropical pollinators that exhibit high diversity in foraging strategies. We provide the first experimental evidence that meliponine group foraging strategies, large colony sizes and aggressive behavior form a suite of traits that enable colonies to improve dominance of rich resources. Using a diverse assemblage of Brazilian stingless bee species and an array of artificial "flowers" that provided a sucrose reward, we compared species' dominance and visitation under unrestricted foraging conditions and with experimental removal of group-foraging species. Dominance does not vary with individual body size, but rather with foraging group size. Species that recruit larger numbers of nestmates (Scaptotrigona aff. depilis, Trigona hyalinata, Trigona spinipes) dominated both numerically (high local abundance) and behaviorally (controlling feeders). Removal of group-foraging species increased feeding opportunities for solitary foragers (Frieseomelitta varia, Melipona quadrifasciata and Nannotrigona testaceicornis). Trigona hyalinata always dominated under unrestricted conditions. When this species was removed, T. spinipes or S. aff. depilis controlled feeders and limited visitation by solitary-foraging species. Because bee foraging patterns determine plant pollination success, understanding the forces that shape these patterns is crucial to ensuring pollination of both crops and natural areas in the face of current pollinator declines. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00040-009-0055-8) contains supplementary material, which is available to authorized

  3. Rayleigh wave group velocity tomography of Gujarat region, Western India and its implications to mantle dynamics

    Science.gov (United States)

    de Lorenzo, Salvatore; Michele, Maddalena; Emolo, Antonio; Tallarico, Andrea

    2017-02-01

    In the present study, fundamental Rayleigh waves with varying period from 10 to 80 s are used to obtain group velocity maps in the northwest Deccan Volcanic Province of India. About 350 paths are obtained using 53 earthquakes (4.8 ≤ M ≥ 7.9) recorded by the SeisNetG (Seismic Network of Gujarat). Individual dispersion curves of group velocity of Rayleigh wave for each source-station path are estimated using multiple filter technique. These curves are used to determine lateral distribution of Rayleigh wave group velocity by tomographic inversion method. Our estimated Rayleigh group velocity at varying depths showed conspicuous corroboration with three tectonic blocks [Kachchh Rift Basin (KRB), Saurashtra Horst (SH), and Mainland Gujarat (MG)] in the region. The seismically active KRB with a thicker crust is characterized as a low velocity zone at a period varying from 10 to 30 s as indicative of mantle downwarping or sagging of the mantle beneath the KRB, while the SH and MG are found to be associated with higher group velocities, indicating the existence of the reduced crustal thickness. The trend of higher group velocity was found prevailed adjacent to the Narmada and Cambay rift basins that also correspond to the reduced crust, suggesting the processes of mantle upwarping or uplifting due to mantle upwelling. The low velocities at periods longer than 40 s beneath the KRB indicate thicker lithosphere. The known Moho depth correlates well with the observed velocities at a period of about 30 s in the Gujarat region. Our estimates of relatively lower group velocities at periods varying from 70 to 80 s may correspond to the asthenospheric flow beneath the region. It is interesting to image higher group velocity for the thinner crust beneath the Arabian Sea adjacent to the west coast of Gujarat at the period of 40 s that may correspond to the upwarped or upwelled mantle beneath the Arabian Sea. Our results have better resolution estimated by a radius of equivalent

  4. 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.

  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. Power Distance and Group Dynamics of an International Project Team: A Case Study

    Science.gov (United States)

    Paulus, Trena M.; Bichelmeyer, Barbara; Malopinsky, Larissa; Pereira, Maura; Rastogi, Polly

    2005-01-01

    Project-based team activities are commonly used in higher education. Teams comprised of members from different national cultures can be faced with unique challenges during the creative process. Hofstede's (1991) cultural dimension of power distance was used to examine one such design team's intra- and inter-group interactions in a graduate-level…

  7. Small Group Dynamics and the Watergate Coverup: A Case Study of Groupthink.

    Science.gov (United States)

    Cline, Rebecca J.

    The decisions President Richard Nixon and his closest advisors made in the Watergate coverup were products of what Irving Janis calls "groupthink." Groupthink, a type of decision-making emphasizing unanimity over objective evaluation, develops when the decision makers (1) form a group of marked cohesiveness, (2) insulate themselves from…

  8. The Centaurus Group and the Outer Halo of NGC 5128: Are they Dynamically Connected?

    CERN Document Server

    Woodley, K A

    2006-01-01

    NGC 5128, a giant elliptical galaxy only $\\sim 4$ Mpc away, is the dominant member of a galaxy group of over 80 probable members. The Centaurus group provides an excellent sample for a kinematic comparison between the halo of NGC 5128 and its surrounding satellite galaxies. A new study, presented here, shows no kinematic difference in rotation amplitude, rotation axis, and velocity dispersion between the halo of NGC 5128, determined from over $\\sim340$ of its globular clusters, and those of the Centaurus group as a whole. These results suggest NGC 5128 could be behaving in part as the inner component to the galaxy group, and could have begun as a large initial seed galaxy, gradually built up by minor mergers and satellite accretions, consistent with simple cold dark matter models. The mass and mass-to-light ratios in the B-band, corrected for projection effects, are determined to be $(1.3\\pm0.5) \\times 10^{12}$ M$_{\\sun}$ and $52\\pm22$ M$_{\\sun}$/L$_{\\sun}$ for NGC 5128 out to a galactocentric radius of 45 kp...

  9. 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…

  10. Nuclear dynamics of RAD52 group homologous recombination proteins in response to DNA damage.

    NARCIS (Netherlands)

    J. Essers (Jeroen); A.B. Houtsmuller (Adriaan); L.R. van Veelen (Lieneke); C. Paulusma (Coen); A.L. Nigg (Alex); A. Pastink (Albert); W. Vermeulen (Wim); J.H.J. Hoeijmakers (Jan); R. Kanaar (Roland)

    2002-01-01

    textabstractRecombination between homologous DNA molecules is essential for the proper maintenance and duplication of the genome, and for the repair of exogenously induced DNA damage such as double-strand breaks. Homologous recombination requires the RAD52 group proteins, including Rad51, Rad52 and

  11. Teachers' Roles in Infants' Play and Its Changing Nature in a Dynamic Group Care Context

    Science.gov (United States)

    Jung, Jeesun

    2013-01-01

    Using a qualitative research approach, this article explores teachers' roles in infants' play and its changing nature in an infant group care setting. Three infant teachers in a child care center were followed over three months. Observations, interviews, ongoing conversations, emails, and reflective notes were used as data sources. Findings…

  12. 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…

  13. 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 throu

  14. The Town Effect: Dynamic Interaction between a Group of Structures and Waves in the Ground

    Science.gov (United States)

    Uenishi, Koji

    2010-11-01

    In a conventional approach, the mechanical behaviour of a structure subjected to seismic or blast waves is treated separately from its surroundings, and in many cases, the dynamic coupling effect between multiple structures and the waves propagating in the ground is disregarded. However, if many structures are built densely in a developed urban area, this dynamic interaction may not become negligible. The first purpose of this contribution is to briefly show the effect of multiple interactions between waves and surface buildings in a town. The analysis is based on a recently developed, fully coupled, rigorous mathematical study, and for simplicity, each building in the town is represented by a rigid foundation, a mass at the top and an elastic spring that connects the foundation and mass. The buildings stand at regular spatial intervals on a linear elastic half-space and are subjected to two-dimensional anti-plane vibrations. It is found that the buildings in this model significantly interact with each other through the elastic ground, and the resonant (eigen) frequencies of the collective system (buildings or town) become lower than that of a single building with the same rigid foundation. This phenomenon may be called the “town effect” or “city effect.” Then, second, it is shown that the actual, unique structural damage pattern caused by the 1976 Friuli, Italy, earthquake may better be explained by this “town effect,” rather than by investigating the seismic performance of each damaged building individually. The results suggest that it may also be possible to evaluate the physical characteristics of incident seismic/blast waves “inversely” from the damage patterns induced to structures by the waves.

  15. Quasielastic neutron scattering measurements of fast process and methyl group dynamics in glassy poly(vinyl acetate)

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Chuhong [Department of Chemistry, School of Engineering and Physical Sciences, Heriot-Watt University, Midlothian, Scotland, Edinburgh, EH14 4AS (United Kingdom); Arrighi, Valeria [Department of Chemistry, School of Engineering and Physical Sciences, Heriot-Watt University, Midlothian, Scotland, Edinburgh, EH14 4AS (United Kingdom)], E-mail: v.arrighi@hw.ac.uk; Gagliardi, Simona [Department of Chemistry, School of Engineering and Physical Sciences, Heriot-Watt University, Midlothian, Scotland, Edinburgh, EH14 4AS (United Kingdom); McEwen, Iain J. [Department of Chemistry, School of Engineering and Physical Sciences, Heriot-Watt University, Midlothian, Scotland, Edinburgh, EH14 4AS (United Kingdom); Tanchawanich, Jeerachada [Department of Chemistry, School of Engineering and Physical Sciences, Heriot-Watt University, Midlothian, Scotland, Edinburgh, EH14 4AS (United Kingdom); Telling, Mark T.F. [ISIS, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 OQX (United Kingdom); Zanotti, J.-M. [Laboratoire Leon Brillouin (CEA-CNRS), CEA Saclay, 91191Gif-sur-Yvette Cedex (France)

    2006-09-29

    The dynamics of poly(vinyl acetate) (PVAc) in the glassy state has been investigated using a range of neutron spectrometers, sampling complementary energy and momentum transfer ranges. By combining the analysis of elastic window scan data at high resolution, medium resolution quasielastic neutron scattering (QENS) spectra and low resolution time-of-flight measurements we identify the molecular processes occurring in PVAc, below the polymer glass transition. Our QENS results are in agreement with the literature data for the methyl group rotation but we also find evidence for a fast process, with activation energy of 1.9 kJ/mol. Although the different instruments provide only limited dynamic information, we attempt to give a homogeneous description of molecular motion across the different energies and Q ranges.

  16. A Framework for Exploring the Dynamics of Autonomous Work Groups in Manufacturing Organizations

    Institute of Scientific and Technical Information of China (English)

    Joseph; W; K; Chan; W; B; Lee

    2002-01-01

    Nowadays, new paradigm of enterprise organization i s constantly changing due to the emergence of the global marketplace, the rise of information technology, and the emphasis of the social developments. This re quires a more flexible form of organization that are more adaptable to rapid cha nges in business environment such as autonomous work groups (AWGs) in order to achieve higher productivity and effectiveness. AWGs are work units responsib le for the production of goods and the provision of servi...

  17. Assessing group dynamics by individual radio satellites in the Mars-500 project

    OpenAIRE

    Johannes, Bernd; Sitev, A. S.; Vinokhodova, A. G.; Salnitski, V.P.; Savchenko, Eduardo; Artyukhova, Anna; Bubeev, Yuri

    2013-01-01

    In a methodological feasibility experiment a wireless group structure (WLGS) monitor system was developed and tested during the Mars500 project. Twice a week each crew member brought a small short-distance radio satellite registering the presence of any other sensor in-room in five second intervals during the wake time. Six satellites were additionally attached to the wall of the simulator’s main compartments. The time being together was registered as well as the signal amplitude providing an...

  18. Diel-scale temporal dynamics recorded for bacterial groups in Namib Desert soil

    Science.gov (United States)

    Gunnigle, Eoin; Frossard, Aline; Ramond, Jean-Baptiste; Guerrero, Leandro; Seely, Mary; Cowan, Don A.

    2017-01-01

    Microbes in hot desert soil partake in core ecosystem processes e.g., biogeochemical cycling of carbon. Nevertheless, there is still a fundamental lack of insights regarding short-term (i.e., over a 24-hour [diel] cycle) microbial responses to highly fluctuating microenvironmental parameters like temperature and humidity. To address this, we employed T-RFLP fingerprinting and 454 pyrosequencing of 16S rRNA-derived cDNA to characterize potentially active bacteria in Namib Desert soil over multiple diel cycles. Strikingly, we found that significant shifts in active bacterial groups could occur over a single 24-hour period. For instance, members of the predominant Actinobacteria phyla exhibited a significant reduction in relative activity from morning to night, whereas many Proteobacterial groups displayed an opposite trend. Contrary to our leading hypothesis, environmental parameters could only account for 10.5% of the recorded total variation. Potential biotic associations shown through co-occurrence networks indicated that non-random inter- and intra-phyla associations were ‘time-of-day-dependent’ which may constitute a key feature of this system. Notably, many cyanobacterial groups were positioned outside and/or between highly interconnected bacterial associations (modules); possibly acting as inter-module ‘hubs’ orchestrating interactions between important functional consortia. Overall, these results provide empirical evidence that bacterial communities in hot desert soils exhibit complex and diel-dependent inter-community associations. PMID:28071697

  19. Diel-scale temporal dynamics recorded for bacterial groups in Namib Desert soil

    Science.gov (United States)

    Gunnigle, Eoin; Frossard, Aline; Ramond, Jean-Baptiste; Guerrero, Leandro; Seely, Mary; Cowan, Don A.

    2017-01-01

    Microbes in hot desert soil partake in core ecosystem processes e.g., biogeochemical cycling of carbon. Nevertheless, there is still a fundamental lack of insights regarding short-term (i.e., over a 24-hour [diel] cycle) microbial responses to highly fluctuating microenvironmental parameters like temperature and humidity. To address this, we employed T-RFLP fingerprinting and 454 pyrosequencing of 16S rRNA-derived cDNA to characterize potentially active bacteria in Namib Desert soil over multiple diel cycles. Strikingly, we found that significant shifts in active bacterial groups could occur over a single 24-hour period. For instance, members of the predominant Actinobacteria phyla exhibited a significant reduction in relative activity from morning to night, whereas many Proteobacterial groups displayed an opposite trend. Contrary to our leading hypothesis, environmental parameters could only account for 10.5% of the recorded total variation. Potential biotic associations shown through co-occurrence networks indicated that non-random inter- and intra-phyla associations were ‘time-of-day-dependent’ which may constitute a key feature of this system. Notably, many cyanobacterial groups were positioned outside and/or between highly interconnected bacterial associations (modules); possibly acting as inter-module ‘hubs’ orchestrating interactions between important functional consortia. Overall, these results provide empirical evidence that bacterial communities in hot desert soils exhibit complex and diel-dependent inter-community associations.

  20. Opinion groups formation and dynamics : structures that last from non lasting entities

    CERN Document Server

    Grauwin, Sébastian

    2015-01-01

    We extend simple opinion models to obtain stable but continuously evolving communities. Our scope is to meet a challenge raised by sociologists of generating "structures that last from non lasting entities". We achieve this by introducing two kinds of noise on a standard opinion model. First, agents may interact with other agents even if their opinion difference is large. Second, agents randomly change their opinion at a constant rate. We show that for a large range of control parameters, our model yields stable and fluctuating polarized states, where the composition and mean opinion of the emerging groups is fluctuating over time.

  1. The Dynamical Yang-Baxter Relation and the Minimal Representation of the Elliptic Quantum Group

    CERN Document Server

    Fan, H; Shi, K J; Yue, R H; Zhao, S Y; Fan, Heng; Hou, Bo-Yu; Shi, Kang-Jie; Yue, Rui-Hong; Zhao, Shao-You

    2003-01-01

    In this paper, we give the general forms of the minimal $L$ matrix (the elements of the $L$-matrix are $c$ numbers) associated with the Boltzmann weights of the $A_{n-1}^1$ interaction-round-a-face (IRF) model and the minimal representation of the $A_{n-1}$ series elliptic quantum group given by Felder and Varchenko. The explicit dependence of elements of $L$-matrices on spectral parameter $z$ are given. They are of five different forms (A(1-4) and B). The algebra for the coefficients (which do not depend on $z$) are given. The algebra of form A is proved to be trivial, while that of form B obey Yang-Baxter equation (YBE). We also give the PBW base and the centers for the algebra of form B.

  2. 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.

  3. Race-Based Humor and Peer Group Dynamics in Adolescence: Bystander Intervention and Social Exclusion.

    Science.gov (United States)

    Mulvey, Kelly Lynn; Palmer, Sally B; Abrams, Dominic

    2016-09-01

    Adolescents' evaluations of discriminatory race-based humor and their expectations about peer responses to discrimination were investigated in 8th- (Mage  = 13.80) and 10th-grade (Mage  = 16.11) primarily European-American participants (N = 256). Older adolescents judged race-based humor as more acceptable than did younger adolescents and were less likely to expect peer intervention. Participants who rejected discrimination were more likely to reference welfare/rights and prejudice and to anticipate that peers would intervene. Showing awareness of group processes, adolescents who rejected race-based humor believed that peers who intervened would be more likely to be excluded. They also disapproved of exclusion more than did participants who supported race-based humor. Results expose the complexity of situations involving subtle discrimination. Implications for bullying interventions are discussed.

  4. 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

    , the frequency of introduction/removal of animals, space allowance in the lying area, group size and number of feeding stations, and starting times for the feeding cycle. All herds had one feeding cycle per 24 h. Six 24-h video recordings in the most settled period with respect to rank relationships (2 to 12...... it was increased in herd 2 (characterized by straw in lying area, low stocking density, low frequency of regrouping). Number of regroupings and space allowance apparently had no obvious effects on the average frequency of aggression or the aggression per sow at risk in periods between introduction of new animals......, but space allowance may have improved social function by weakening the association between activity and aggression. Due to the small number of herds included the present results were descriptive rather than conclusive. However, the study supports the suggestions that provision of unchopped straw as bedding...

  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. Collective Decision Dynamics in Group Evacuation: Modeling Tradeoffs and Optimal Behavior

    CERN Document Server

    Schlesinger, Kimberly J; Ali, Imtiaz; Carlson, Jean M

    2016-01-01

    Quantifying uncertainties in collective human behavior and decision making is crucial for ensuring public health and safety, enabling effective disaster response, informing the design of transportation and communication networks, and guiding the development of new technologies. However, modeling and predicting such behavior is notoriously difficult, due to the influence of a variety of complex factors such as the availability and uncertainty of information, the interaction and influence of social groups and networks, the degree of risk or time pressure involved in a situation, and differences in individual personalities and preferences. Here, we develop a stochastic model of human decision making to describe the empirical behavior of subjects in a controlled experiment simulating a natural disaster scenario. We compare the observed behavior to that of statistically optimal Bayesian decision makers, quantifying the extent to which human decisions are optimal and identifying the conditions in which sub-optimal ...

  7. NMR and molecular dynamics studies of the conformational epitope of the type III group B Streptococcus capsular polysaccharide and derivatives.

    Science.gov (United States)

    Brisson, J R; Uhrinova, S; Woods, R J; van der Zwan, M; Jarrell, H C; Paoletti, L C; Kasper, D L; Jennings, H J

    1997-03-18

    The conformational epitope of the type III group B Streptococcus capsular polysaccharide (GBSP III) exhibits unique properties which can be ascribed to the presence of sialic acid in its structure and the requirement for an extended binding site. By means of NMR and molecular dynamics studies on GBSP III and its fragments, the extended epitope of GBSP III was further defined. The influence of sialic acid on the conformational properties of GBSP III was examined by performing conformational analysis on desialylated GBSP III, which is identical to the polysaccharide of Streptococcus pneumoniae type 14, and also on oxidized and reduced GBSP III. Conformational changes were gauged by 1H and 13C chemical shift analysis, NOE, 1D selective TOCSY-NOESY experiments, J(HH) and J(CH) variations, and NOE of OH resonances. Changes in mobility were examined by 13C T1 and T2 measurements. Unrestrained molecular dynamics simulations with explicit water using the AMBER force field and the GLYCAM parameter set were used to assess static and dynamic conformational models, simulate the observable NMR parameters and calculate helical parameters. GBSP III was found to be capable of forming extended helices. Hence, the length dependence of the conformational epitope could be explained by its location on extended helices within the random coil structure of GBSP III. The interaction of sialic acid with the backbone of the PS was also found to be important in defining the conformational epitope of GBSP III.

  8. 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

  9. 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

  10. 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.

  11. 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.

  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. High mobility group protein 1: A collaborator in nucleosome dynamics and estrogen-responsive gene expression

    Institute of Scientific and Technical Information of China (English)

    William M Scovell

    2016-01-01

    High mobility group protein 1(HMGB1) is a multifunctional protein that interacts with DNA and chromatin to influence the regulation of transcription, DNA replication and repair and recombination. We show that HMGB1 alters the structure and stability of the canonical nucleosome(N) in a nonenzymatic,adenosine triphosphate-independent manner. As a result, the canonical nucleosome is converted to two stable, physically distinct nucleosome conformers. Although estrogen receptor(ER) does not bind to its consensus estrogen response element within a nucleosome, HMGB1 restructures the nucleosome to facilitate strong ER binding. The isolated HMGB1-restructured nucleosomes(N’ and N’’) remain stable and exhibit a number of characteristics that are distinctly different from the canonical nucleosome. These findings complement previous studies that showed(1) HMGB1 stimulates in vivo transcriptional activation at estrogen response elements and(2) knock down of HMGB1 expression by siR NA precipitously reduced transcriptional activation. The findings indicate that a major facet of the mechanism of HMGB1 action involves a restructuring of aspects of the nucleosome that appear to relax structural constraints within the nucleosome. The findings are extended to reveal the differences between ER and the other steroid hormone receptors. A working proposal outlines mechanisms that highlight the multiple facets that HMGB1 may utilize in restructuring the nucleosome.

  14. 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.

  15. The dynamics of polycomb group proteins in early embryonic nervous system in mouse and human.

    Science.gov (United States)

    Qi, Lu; Cao, Jing-Li; Hu, Yi; Yang, Ji-Gao; Ji, Yuan; Huang, Jing; Zhang, Yi; Sun, Da-Guang; Xia, Hong-Fei; Ma, Xu

    2013-11-01

    Polycomb group (PcG) proteins are transcription regulatory proteins that control the expression of a variety of genes and the antero-posterior neural patterning from early embryogenesis. Although expression of PcG genes in the nervous system has been noticed, but the expression pattern of PcG proteins in early embryonic nervous system is still unclear. In this study, we analyzed the expression pattern of PRC1 complex members (BMI-1 and RING1B) and PRC2 complex members (EED, SUZ12 and EZH2) in early embryonic nervous system in mouse and human by Western blot and Immunohistochemistry. The results of Western blot showed that EED protein was significantly up-regulated with the increase of the day of pregnancy during the early embryogenesis in mouse. BMI-1 protein level was significantly increased from the day 10 of pregnancy, when compared with the day 9 of pregnancy. But the SUZ12, EZH2 and RING1B protein level did not change significantly. From the results of Immunohistochemistry, we found that the four PcG proteins were all expressed in the fetal brain and fetal spinal cord in mouse. In human, the expression of EED, SUZ12, and EZH2 was not significantly different in cerebral cortex and sacral spinal cord, but BMI-1 and RING1B expression was enhanced with the development of embryos in early pregnancy. Collectively, our findings showed that PRC1 and PRC2 were spatiotemporally expressed in brain and spinal cord of early embryos.

  16. Time development in the early history of social networks: link stabilization, group dynamics, and segregation.

    Directory of Open Access Journals (Sweden)

    Jesper Bruun

    Full Text Available 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

  17. Sedimentology and Sedimentary Dynamics of the Desmoinesian Cherokee Group, Deep Anadarko Basin, Texas Panhandle

    Science.gov (United States)

    Hu, N.; Loucks, R.; Frebourg, G.

    2015-12-01

    Understanding the spatial variability of deep-water facies is critical to deep-water research because of its revealing information about the relationship between desity flow processes and their resultant sedimentary sequences. The Cherokee Group in the Anadarko Basin, northeastern Texas Panhandle, provides an opportunity to investigate an icehouse-greenhouse Pennsylvanian hybrid system that well demonstrates the intricacies of vertical and lateral facies relationships in an unconfined fan-delta fed deep-water slope to basinal setting. The stratigraphic section ranges in thickness from 150 to 460 m. The cyclic sedimentation and foreland basin tectonics resulted in a complex stratal architecture that was sourced by multiple areas of sediment input. This investigation consists of wireline-log and core data. Five-thousand wireline logs were correlated in an area of over 9500 sq km to map out six depositional sequences that are separated by major flooding events. These events are correlative over the whole area of study. Six cores, that sample nearly the complete section, were described for lithofacies. Lithofacies are recognized based on depositional features and mineralogy:(1) Subarkose, (2) Lithicarkoses, (3) Sandy siliciclastic conglomerate, (4) Muddy calcareous conglomerate, (5) Crinoidal packstone, (6) Oodic grainstone, (7)Pelodic grainstone, (8) Ripple laminated mudrock, (9) faint laminated mudrock. The integration of isopachs of depositional sequences with the lithofacies has allowed the delineation of the spatial and temporal evolution of the slope to basin-floor system. Thin-to-thick bedded turbidites, hyperconcentrated density flow deposits (slurry beds), and debris and mud flow deposits were observed and can be used to better predicte lithofacies distributions in areas that have less data control. These mixed siliciclastic and carbonate deposits can be carrier beds for the hydrocarbons generated from the enclosing organic-rich (TOC ranges from 0.55 to 6.77wt

  18. Effect of hydrophobic groups on the adsorption conformation of modified polycarboxylate superplasticizer investigated by molecular dynamics simulation

    Science.gov (United States)

    Zhao, Hongxia; Wang, Yanwei; Yang, Yong; Shu, Xin; Yan, Han; Ran, Qianping

    2017-06-01

    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 (C2S) 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 C2S 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 C2S surface and lowered the water density. Perturbations to the interfacial water density were found to correlate nicely with the adsorbed conformations of PCEs.

  19. Chemo-dynamical evolution model: Enrichment of r-process elements in the Local Group dwarf galaxies

    Science.gov (United States)

    Hirai, Yutaka; Ishimaru, Yuhri; Saitoh, Takayuki R.; Fujii, Michiko S.; Hidaka, Jun; Kajino, Toshitaka

    2016-08-01

    Neutron star mergers are one of the candidate astrophysical site(s) of r-process. Several chemical evolution studies however pointed out that the observed abundance of r-process is difficult to reproduce by neutron star mergers. In this study, we aim to clarify the enrichment of r-process elements in the Local Group dwarf galaxies. We carry out numerical simulations of galactic chemo-dynamical evolution using an N-body/smoothed particle hydrodynamics code, ASURA. We construct a chemo-dynamical evolution model for dwarf galaxies assuming that neutron star mergers are the major source of r-process elements. Our models reproduce the observed dispersion in [Eu/Fe] as a function of [Fe/H] with neutron star mergers with a merger time of 100 Myr. We find that star formation efficiency and metal mixing processes during the first <~ 300 Myr of galaxy evolution are important to reproduce the observations. This study supports that neutron star mergers are a major site of r-process.

  20. 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.

  1. 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.

  2. Structures and dynamics of transnational cooperation networks: evidence based on Local Action Groups in the Veneto Region, Italy

    Directory of Open Access Journals (Sweden)

    Elena Pisani

    2014-12-01

    Full Text Available The paper assesses the structures and dynamics of transnational cooperation projects promoted by Local Action Groups (LAGs in different periods (from LEADER II to LEADER Axis using Social Network Analysis (SNA in a specific case study: the Veneto Region in Italy. The classical indexes of SNA have been critically examined, and the paper also presents innovative indexes that can capture the peculiarity of transnational cooperation: disaggregated densities of the network and transnational centrality of the node. These indexes are useful in order to quantify how transnational a network actually is, and to measure the power-information that each actor (LAG can acquire through its transnational contacts. The methodology can become a tool for Managing Authorities to implement new forms of evaluation of transnational cooperation of LAGs.

  3. Dynamic regulatory interactions of Polycomb group genes: MEDEA autoregulation is required for imprinted gene expression in Arabidopsis.

    Science.gov (United States)

    Baroux, Célia; Gagliardini, Valeria; Page, Damian R; Grossniklaus, Ueli

    2006-05-01

    The imprinted Arabidopsis Polycomb group (PcG) gene MEDEA (MEA), which is homologous to Enhancer of Zeste [E(Z)], is maternally required for normal seed development. Here we show that, unlike known mammalian imprinted genes, MEA regulates its own imprinted expression: It down-regulates the maternal allele around fertilization and maintains the paternal allele silent later during seed development. Autorepression of the maternal MEA allele is direct and independent of the MEA-FIE (FERTILIZATION-INDEPENDENT ENDOSPERM) PcG complex, which is similar to the E(Z)-ESC (Extra sex combs) complex of animals, suggesting a novel mechanism. A complex network of cross-regulatory interactions among the other known members of the MEA-FIE PcG complex implies distinct functions that are dynamically regulated during reproduction.

  4. Quantitative Evaluation of the Dispersion of Graphene Sheets With and Without Functional Groups Using Molecular Dynamics Simulations.

    Science.gov (United States)

    Cha, JinHyeok; Kyoung, Woomin; Song, Kyonghwa; Park, Sangbaek; Lim, Taewon; Lee, Jongkook; Kang, Hyunmin

    2016-12-01

    Nanofluids with enhanced thermal properties are candidates for thermal management in automotive systems, with scope for improving energy efficiency. In particular, many studies have reported on dispersions of nanoparticles with long-term stability in the base fluid, with qualitative evaluations of the dispersion stability via either the naked eye or optical instruments. Additives such as surfactants can be used to enhance the dispersion of nanoparticles; however, this may diminish their intrinsic thermal properties. Here, we describe molecular dynamics simulations of nanofluids containing graphene sheets dispersed in ethylene glycol and water. We go on to suggest a quantitative evaluation method for the degree of dispersion, based on the ratio of the total number of nanoparticles to the number of clustered nanoparticles. Moreover, we investigate the effects of functional groups on the surface of graphene, which are expected to improve the dispersion without requiring additives such as surfactants due to steric hindrance and chemical affinity for the surrounding fluid. We find that, for pure graphene, the degree of dispersion decreased as the quantity of graphene sheets increased, which is attributed to an increased probability of aggregation at higher loadings; however, the presence of functional groups inhibited the graphene sheets from forming aggregates.

  5. 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.

  6. Group dynamics and landscape features constrain the exploration of herds in fusion-fission societies: the case of European roe deer.

    Directory of Open Access Journals (Sweden)

    Olivier Pays

    Full Text Available Despite the large number of movement studies, the constraints that grouping imposes on movement decisions remain essentially unexplored, even for highly social species. Such constraints could be key, however, to understanding the dynamics and spatial organisation of species living in group fusion-fission systems. We investigated the winter movements (speed and diffusion coefficient of groups of free-ranging roe deer (Capreolus capreolus, in an agricultural landscape characterised by a mosaic of food and foodless patches. Most groups were short-lived units that merged and split up frequently during the course of a day. Deer groups decreased their speed and diffusion rate in areas where food patches were abundant, as well as when travelling close to main roads and crest lines and far from forests. While accounting for these behavioural adjustments to habitat features, our study revealed some constraints imposed by group foraging: large groups reached the limit of their diffusion rate faster than small groups. The ability of individuals to move rapidly to new foraging locations following patch depression thus decreases with group size. Our results highlight the importance of considering both habitat heterogeneity and group dynamics when predicting the movements of individuals in group fusion-fission societies. Further, we provide empirical evidence that group cohesion can restrain movement and, therefore, the speed at which group members can explore their environment. When maintaining cohesion reduces foraging gains because of movement constraints, leaving the group may become a fitness-rewarding decision, especially when individuals can join other groups located nearby, which would tend to maintain highly dynamical group fusion-fission systems. Our findings also provide the basis for new hypotheses explaining a broad range of ecological patterns, such as the broader diet and longer residency time reported for larger herbivore groups.

  7. Dynamical History Of The Local Group In ΛCDM slowromancapii@ - Including External Perturbers In 3D

    Science.gov (United States)

    Banik, Indranil; Zhao, Hongsheng

    2017-01-01

    We attempt to fit the observed radial velocities (RVs) of ˜ 30 Local Group (LG) galaxies using a 3D dynamical model of it and its immediate environment within the context of the standard cosmological paradigm, ΛCDM. This extends and confirms the basic results of our previous axisymmetric investigation of the LG (MNRAS, 459, 2237). We find that there remains a tendency for observed RVs to exceed those predicted by our best-fitting model. The typical mismatch is slightly higher than in our 2D model, with a root mean square value of ˜ 50 km/s. Our main finding is that including the 3D distribution of massive perturbing dark matter halos is unlikely to help greatly with the high velocity galaxy problem. Nonetheless, the 2D and 3D results differ in several other ways such as which galaxies' RVs are most problematic and the preferred values of parameters common to both models. The anomalously high RVs of several LG dwarfs may be better explained if the Milky Way (MW) and Andromeda (M31) were once moving much faster than in our models. This would allow LG dwarfs to gain very high RVs via gravitational slingshot encounters with a massive fast-moving galaxy. Such a scenario is possible in some modified gravity theories, especially those which require the MW and M31 to have previously undergone a close flyby. In a ΛCDM context, however, this scenario is not feasible as the resulting dynamical friction would cause a rapid merger.

  8. At your own risk : The importance of group dynamics and peer processes in adolescent peer groups for adolescents’ involvement in risk behaviors

    NARCIS (Netherlands)

    Pattiselanno, Kim Lianne

    2016-01-01

    During adolescence peers become increasingly important to the social and emotional development of adolescents. Peer groups form one of the most important settings where adolescents socialize, find social support, and feel connected and accepted. However, these groups also form a context where

  9. Using Innovative Outliers to Detect Discrete Shifts in Dynamics in Group-Based State-Space Models

    Science.gov (United States)

    Chow, Sy-Miin; Hamaker, Ellen L.; Allaire, Jason C.

    2009-01-01

    Outliers are typically regarded as data anomalies that should be discarded. However, dynamic or "innovative" outliers can be appropriately utilized to capture unusual but substantively meaningful shifts in a system's dynamics. We extend De Jong and Penzer's 1998 approach for representing outliers in single-subject state-space models to a…

  10. A brief introduction to the Nonlinear Atmospheric Dynamics Research Group in the State Key Laboratory of LASG

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    @@Nonlinear atmospheric dynamics is an interdisciplinary branch of atmospheric sciences,geophysical fluid dynamics and nonlinear sciences.As a basis for numerical weather prediction and short-term climate predication,it is a frontier of rapidly developing atmospheric sciences in recent years.

  11. A new two-round dynamic authenticated contributory group key agreement protocol using elliptic curve Diffie–Hellman with privacy preserving public key infrastructure

    Indian Academy of Sciences (India)

    Vankamamidi S Naresh; Nistala V E S Murthy

    2015-10-01

    In this paper a new two-round authenticated contributory group key agreement based on Elliptic Curve Diffie–Hellman protocol with Privacy Preserving Public Key Infrastructure (PP-PKI) is introduced and is extended to a dynamic authenticated contributory group key agreement with join and leave protocols for dynamic groups. The proposed protocol provides such security attributes as forward secrecy, backward secrecy, and defense against man in the middle (MITM) and Unknown keyshare security attacks and also authentication along with privacy preserving attributes like anonymity, traceability and unlinkability. In the end, they are compared with other popular Diffie–Hellman and Elliptic Curve Diffie–Hellman based group key agreement protocols and the results are found to be satisfactory.

  12. 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...

  13. Interactions between the developmental and adult social environments mediate group dynamics and offspring traits in Drosophila melanogaster.

    Science.gov (United States)

    Morimoto, Juliano; Ponton, Fleur; Tychsen, Ilona; Cassar, Jason; Wigby, Stuart

    2017-06-15

    Developmental conditions can strongly influence adult phenotypes and social interactions, which in turn affect key evolutionary processes such as sexual selection and sexual conflict. While the implications of social interactions in phenotypically mixed populations at the individual level are increasingly well known, how these effects influence the fate of groups remains poorly understood, which limits our understanding of the broader ecological implications. To address this problem we manipulated adult phenotypes and social composition in Drosophila melanogaster - by experimentally manipulating the larval density of the group-members - and measured a range of group-level outcomes across the lifespan of groups. Adult groups composed of exclusively low larval-density individuals showed high courtship levels, and low early reproductive rates, group growth rates, offspring mass and offspring eclosion success, relative to high larval-density or mixed larval-density groups. Furthermore, high larval-density groups had lower survival. Offspring mass increased with time, but at a reduced rate in groups when male group members (but not females) were from a mixture of larval-densities; peak reproductive rates were also earlier in these groups. Our results suggest that that variation in developmental conditions experienced by adult group members can modify the reproductive output of groups.

  14. Identifying dynamically young galaxy groups via wide-angle tail galaxies: A case study in the COSMOS field at z=0.53

    CERN Document Server

    Oklopcic, A; Giodini, S; Zamorani, G; Birzan, L; Schinnerer, E; Carilli, C L; Finoguenov, A; Lilly, S; Koekemoer, A; Scoville, N Z

    2010-01-01

    We present an analysis of a wide-angle tail (WAT) radio galaxy located in a galaxy group in the COSMOS field at a redshift of z=0.53 (hereafter CWAT-02). We find that the host galaxy of CWAT-02 is the brightest galaxy in the group, although it does not coincide with the center of mass of the system. Estimating a) the velocity of CWAT-02, relative to the intra-cluster medium (ICM), and b) the line-of-sight peculiar velocity of CWAT-02's host galaxy, relative to the average velocity of the group, we find that both values are higher than those expected for a dominant galaxy in a relaxed system. This suggests that CWAT-02's host group is dynamically young and likely in the process of an ongoing group merger. Our results are consistent with previous findings showing that the presence of a wide-angle tail galaxy in a galaxy group or cluster can be used as an indicator of dynamically young non-relaxed systems. Taking the unrelaxed state of CWAT-02's host group into account, we discuss the impact of radio-AGN heating...

  15. The effect of device number and role assignment on social group dynamics in location-based learning

    DEFF Research Database (Denmark)

    Christensen, Bianca Clavio; Jørgensen, Nicolai Melgaard; Poulsen, Mark Kronborg

    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...... 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....

  16. The effect of device number and role assignment on social group dynamics in location-based learning

    DEFF Research Database (Denmark)

    Christensen, Bianca Clavio; Jørgensen, Nicolai Melgaard; Poulsen, Mark Kronborg

    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...

  17. 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.

  18. A shared past and a common future: the Portuguese colonial war and the dynamics of group-based guilt

    NARCIS (Netherlands)

    Figueiredo, A.; Valentim, J.; Doosje, B.

    2011-01-01

    In the present study we examine feelings of group-based guilt among Portuguese people in relation to the Portuguese colonial war, and their consequences for social behaviour. Specifically, we focus on the way Portuguese university students identify with their national group and the outgroup and thei

  19. A shared past and a common future: the Portuguese colonial war and the dynamics of group-based guilt

    NARCIS (Netherlands)

    Figueiredo, A.; Valentim, J.; Doosje, B.

    2011-01-01

    In the present study we examine feelings of group-based guilt among Portuguese people in relation to the Portuguese colonial war, and their consequences for social behaviour. Specifically, we focus on the way Portuguese university students identify with their national group and the outgroup and thei

  20. 广义质量替代的曲柄群机构动平衡%Dynamic balancing of crank group mechanism based on generalized mass substitution

    Institute of Scientific and Technical Information of China (English)

    刘言松; 曹巨江

    2016-01-01

    根据曲柄群机构中连杆桁架的质心分布特点,利用广义质量替代法将连杆桁架质量向曲柄与连杆桁架的3个铰接点替代,从而将曲柄群机构分解为若干个I类和II类曲柄单元,把曲柄群机构的动平衡问题转化为I类曲柄单元的动平衡问题。计算表明。当 I 类曲柄单元实现动平衡时,曲柄群机构也实现了动平衡。结论对简化曲柄群机构的结构,减少该机构的基础振动具有较好的指导意义。%According to the distribution characteristics of center of mass of the crank group mechanism,the mechanism is broken into some crank units named class I crank unit or class II crank unit,by generalized mass substitution in which the mass of the connecting rod truss is substituted on the 3 hinged points,and the dynamic balancing of the crank group mecha-nism is converted to the dynamic balance of class I crank unit.The calculation example shows that the crank group mechanism is a dynamic balancing mechanism when each class I crank unit is a dynamic balancing rotor.The conclusions may be helpful for reducing the foundation vibration of the mechanism and simplifying the structure in the design of the crank group mechanism.

  1. 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.

  2. 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.

  3. 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.

  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. Effects of peripheral dynamic movements on the lower-limb circulation assessed by thermography: three one-group studies

    Science.gov (United States)

    Kaerki, Anne; Laehdeniemi, Matti

    2002-03-01

    Peripheral dynamic movements are used as part of postoperative protocols and for preventing vascular complications during bed rest. The effects of peripheral movements have not been studied. The purposes of these studies were to explain the effects of peripheral dynamic movements on lower limb circulation. The aim was also to explain how other factors like sex, age, BMI, medication, smoking, sports activity etc. affect the circulation. Healthy young subjects (N=19), healthy elderly subjects (N=19) and diabetic subjects (N=21) participated in the studies between 1997 and 1999. The study design was the same in each study. Infrared technology and image processing belong to our focus fields of applied research and IR is widely used in our real time industrial applications including also ongoing research of new possibilities. This paper presents the results of our newest application of IR thermography, where it was used to measure the skin temperature over the soleus muscle during and after dynamic ankle movements. The results showed that the skin temperature increased further during the recovery period after movements, and temperature was highest after 3- 5 minutes. Diabetic male subjects were the only subgroup that had immediate decrease during recovery period. The studies showed that smoking had a negative effect on circulation. BMI had also negative correlation (-0,356), showing that subjects with higher BMI had less increase. The results proved that peripheral movements were effective for increasing circulation in the soleus muscle and the effect was still seen after 15 minutes.

  6. Change of caged dynamics at Tg in hydrated proteins: Trend of mean squared displacements after correcting for the methyl-group rotation contribution

    Science.gov (United States)

    Ngai, K. L.; Capaccioli, S.; Paciaroni, A.

    2013-06-01

    The question whether the dynamics of hydrated proteins changes with temperature on crossing the glass transition temperature like that found in conventional glassformers is an interesting one. Recently, we have shown that a change of temperature dependence of the mean square displacement (MSD) at Tg is present in proteins solvated with bioprotectants, such as sugars or glycerol with or without the addition of water, coexisting with the dynamic transition at a higher temperature Td. The dynamical change at Tg is similar to that in conventional glassformers at sufficiently short times and low enough temperatures, where molecules are mutually caged by the intermolecular potential. This is a general and fundamental property of glassformers which is always observed at or near Tg independent of the energy resolution of the spectrometer, and is also the basis of the dynamical change of solvated proteins at Tg. When proteins are solvated with bioprotectants they show higher Tg and Td than the proteins hydrated by water alone, due to the stabilizing action of excipients, thus the observation of the change of T-dependence of the MSD at Tg is unobstructed by the methyl-group rotation contribution at lower temperatures [S. Capaccioli, K. L. Ngai, S. Ancherbak, and A. Paciaroni, J. Phys. Chem. B 116, 1745 (2012)], 10.1021/jp2057892. On the other hand, in the case of proteins hydrated by water alone unambiguous evidence of the break at Tg is hard to find, because of their lower Tg and Td. Notwithstanding, in this paper, we provide evidence for the change at Tg of the T-dependence of proteins hydrated by pure water. This evidence turns out from (i) neutron scattering experimental investigations where the sample has been manipulated by either full or partial deuteration to suppress the methyl-group rotation contribution, and (ii) neutron scattering experimental investigations where the energy resolution is such that only motions with characteristic times shorter than 15 ps can be

  7. MODELING THE DYNAMICS OF THREE FUNCTIONAL GROUPS OF MACROALGAE IN TROPICAL SEAGRASS HABITATS. (R828677C004)

    Science.gov (United States)

    A model of three functional groups of macroalgae, drift algae, rhizophytic calcareous algae, and seagrass epiphytes, was developed to complement an existing seagrass production model for tropical habitats dominated by Thalassia testudinum (Turtle-grass). The current modeling e...

  8. Spatiotemporal Patterns and Dynamics of Species Richness and Abundance of Woody Plant Functional Groups in a Tropical Forest Landscape of Hainan Island,South China

    Institute of Scientific and Technical Information of China (English)

    Zhi-Dong Zhang; Run-Guo Zang; Yao-Dong Qi

    2008-01-01

    Tropical forests are among the most species-diverse ecosystems on Earth. Their structures and ecological functions are complex to understand. Functional group is defined as a group of species that play similar roles in an ecosystem. The functional group approach has been regarded as an effective way of linking the compositions of complex ecosystems with their ecological functions. To understand the variation of functional groups in species-rich ecosystems after disturbance, the present study investigated the spatial pattern and temporal dynamics of woody plants in a typically fragmented natural forest landscape of Hainan Island in South China. The study area was classified into eight landscape types based on vegetation type, disturbance manner and the time of recovery. The woody plant species were aggregated into seven functional groups based on the growth form, successional status and plant size. The results gained from the present study showed that all functional groups, except for the emergent and canopy tree species, were present in all eight landscape types. Each landscape type had different numbers of dominant functional groups. There are similar species richness and stem abundance structure among functional groups between mid-successional clear cut lowland rainforest and old growth tropical coniferous forest. This similarity exists in selective logged lowland rainforest and old-growth lowland rainforest, as well as among landscape types of montane rainforest. The functional groups with the same successional status had similar patterns of species richness and stem abundance ratios among different landscape types. The variation patterns of functional groups along the successional stages in terms of species richness and stem abundance among the tropical lowland rainforest landscape types were more similar to each other than those in the tropical montane reinforest landscape types. This study provides further support for the competition-colonization tradeoff and

  9. 群体动力学视角下新生适应性集体活动的组织与实施%Organizing and Conducting Adaptive Group Activities among College Freshmen from the Perspective of Group Dynamics

    Institute of Scientific and Technical Information of China (English)

    于超美; 叶威惠

    2014-01-01

    文章在对新生群体、新生适应性问题进行分类分析的基础上,从群体动力学的角度对解决新生适应问题进行审视,对针对新生适应性问题开展的集体活动的组织与实施进行探讨,在实证基础上阐述并完善大型集体活动牵引个体心理建设,进一步提升育人效果。%After analyzing the group characteristics of college freshmen and their adaptive problems, this article examines from the perspective of group dynamics how to solve the problems and discusses how to organize and conduct group activities aimed at the problems.It gives an evidence based expla-nation of how well designed large scale group activities can help build individual psychology and en-hance education.

  10. Group-based trajectory modeling (GBMT) of citations in scholarly literature: dynamic qualities of "transient" and "sticky knowledge claims"

    NARCIS (Netherlands)

    Baumgartner, S.E.; Leydesdorff, L.

    2014-01-01

    Group-based trajectory modeling (GBTM) is applied to the citation curves of articles in six journals and to all citable items in a single field of science (virology, 24 journals) to distinguish among the developmental trajectories in subpopulations. Can citation patterns of highly-cited papers be

  11. 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...... and clear cell mRCC participating in an ongoing prospective randomized phase II trial comprising interleukin-2-based immunotherapy and bevacizumab were included in this preliminary analysis. All patients had a follow-up time of at least 2 years. Interpretation of DCE-CT (max slope method) was performed...... not reached, P = 0.031). CONCLUSIONS: Dynamic contrast-enhanced CT is a potential biomarker in patients with mRCC. High baseline BF and reductions in BF and BV during early treatment are associated with improved outcome. Large-scale studies are required....

  12. 2+1-Gravity and The Embedding its Dynamical Symmetry and Para-Supersymmetry into SO(4,c) Group

    CERN Document Server

    Jafarizadeh, M A; Moayedi, S K

    1999-01-01

    Some special solutions of the Einstein-Maxwell action with a non-negative cosmological constant and a very heavy point mass particle have been obtained. The solutions correspond to static spacetime of locally constant curvature in its spatial part and a constant magnetic field of a magnetic monopole together with deficit of angle at the location of point mass. The quantum mechanics of a point particle in these spacetimes in the absence of angular deficit has been solved algebraically both relativistically and non-relativistically. It has been also shown that these 2-dimensional Hamiltonians have the degeneracy group of GL(2,c) type and para-supersymmetry of arbitrary order or shape invariance, which is originated from a SO(4,c) group.

  13. Small Group Dynamics in the Evolution of Global Network Terrorism: A Comprehensive, People-Based Approach. Part A: Select Publications

    Science.gov (United States)

    2009-10-07

    laboratory studies). Expectations that people in political or intergroup conflicts will com- promise sacred values in exchange for much needed material...He has published widely on the psychology of terrorism and intergroup conflict . Justin Magouirk spent two years as the Manager and then Executive...friends, and some kin. Terrorist groups arise within specific "scenes": neighborhoods, schools (classes, dorms). workplaces , common leisure activities

  14. Chemo-dynamical evolution of the Local Group dwarf galaxies: The origin of r-process elements

    Science.gov (United States)

    Hirai, Y.; Ishimaru, Y.; Saitoh, T. R.; Fujii, M. S.; Hidaka, J.; Kajino, T.

    2016-06-01

    The r-process elements such as Au, Eu, and U are observed in the extremely metal-poor stars in the Milky Way halo and the Local Group dwarf galaxies. However, the origin of r-process elements has not yet been identified. The abundance of r-process elements of stars in the Local Group galaxies provides clues to clarify early evolutionary history of galaxies. It is important to understand the chemical evolution of the Local Group dwarf galaxies which would be building blocks of the Milky Way. In this study, we perform a series of N-body/smoothed particle hydrodynamic simulations of dwarf galaxies. We show that neutron star mergers can reproduce the observation of r-process elements. We find that the effects of gas mixing processes including metals in the star-forming region of a typical scale of giant molecular clouds ¥sim 10-100 pc play significant roles in the early chemical enrichment of dwarf galaxies. We also find that the star formation rate of ˜ 10^{-3} M_{⊙}yr^{-1} in early epoch (<1 Gyr) of galactic halo evolution is necessary for these results. Our results suggest that neutron star mergers are a major site of r-process.

  15. Roles of the methyl and methylene groups of mercapto acids in the photoluminescence efficiency and carrier trapping dynamics of CdTe QDs.

    Science.gov (United States)

    Chandra Sekhar, M; De, Apurba; Hossain, Sk Saddam; Samanta, Anunay

    2017-01-04

    Surface protection using an appropriate ligand is essential for controlling the size, stability and luminescence properties of the quantum dots (QDs). Though 3-mercaptopropanoic acid (3-MPA) is regarded as the most suitable protecting ligand among the mercapto acids for water soluble CdTe QDs, one receives a different picture from recent studies, which report a much higher luminescence efficiency of 3-mercaptobutyric acid (3-MBA) capped QDs compared with those capped by 3-MPA and attribute the observation to the influence of the side methyl group of mercapto acids. Herein we report the luminescence properties and carrier trapping dynamics of four different, but structurally related mercapto acid capped CdTe QDs prepared using a different method. The results show that these QDs are much more fluorescent than those prepared directly in an aqueous environment and surprisingly, no enhanced luminescence for the QDs capped by mercapto acids containing a side methyl group is observed. Ultrafast pump-probe measurements confirm these results in addition to providing insight into the carrier trapping dynamics of these systems. It is shown that our findings, which appear to be in conflict with the recent literature, can be rationalized and the exact role of the side methyl group of the mercapto acids can be understood by careful analysis of the results taking into consideration the difference in the methods of preparation of the QDs in the two cases.

  16. 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.

  17. 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, Eugénie S; Carman, Tobey B; McGuire, A David

    2014-03-01

    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 with 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. © 2013 John Wiley & Sons Ltd.

  18. 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. PMID:27594906

  19. 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.

  20. Planktonic protist communities in semi-enclosed mariculture waters: temporal dynamics of functional groups and their responses to environmental conditions

    Institute of Scientific and Technical Information of China (English)

    XU Henglong; WARREN Alan; AL-RASHEID Khaled A S; ZHU Mingzhuang; SONG Weibo

    2010-01-01

    The functional groups of planktonic protist communities and their responses to the changes of environmental conditions were investigated in a semi-enclosed shrimp-farming pond in Qingdao,Shandong Province,China,during a six-month study period(a complete shrimp-culture cycle)from May to October 2002.The results reveal that:(1)the protist communities represented five trophic and functional groups of the species identified,about 60% were photoautotrophs,20% algivores,12%bacterivores,5% raptors and about 3% non-selectives;(2)the photoautotrophs,algivores and bacterivores were the primary contributors to the changes in the protist communities in short temporal scales,the succession of dominance typically being bacterivores→photoautotrophs→algivores,with the raptors dominating the protist communities in a single sample(early June);(3)the photoautotrophs and non-selectives were the primary contributors to the peak of protist abundance in early October whereas the photoautotrophs,bacterivores,raptors and non-selectives mainly gave rise to two bimodal peaks of biomass in July and October respectively;(4)five functional groups of protist communities represented significant correlations with water nutrients(i.e.,NH3-N,NO3-N,and PO4),either alone or in combination with temperature,of which algivores and raptors were strongly correlated with phosphate and the concentration of Chl a,while bacterivores were strongly related to nitrogen and the concentration of bacteria.These findings confirm that planktonic protists are potentially useful bioindicators of water quality in the semi-enclosed mariculture system.

  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. Dynamic Evolution of an X-shaped Structure above a Trans-equatorial Quadrupole Solar Active Region Group

    CERN Document Server

    Sun, J Q; Guo, Y; Ding, M D; Li, Y

    2014-01-01

    In the solar corona, magnetic reconnection usually takes place at the singular configuration of magnetic field, in particular near a magnetic null owing to its high susceptibility to perturbations. In this Letter, we report a rare X-shaped structure, encompassing a magnetic null, above a trans-equatorial quadrupole active region group that is well observed by the Atmospheric Imaging Assembly (AIA). The observations show that this X-shaped structure is visible in all AIA EUV passbands and stably exists for days. However, possibly induced by flare activities at the northern part of the quadrupole active region group, the X-shaped structure starts to destabilize and meanwhile a jet erupted near its center at 15:05 UT on 2013 October 7. Through the non-linear force-free field modeling, we identify a magnetic null, which is above the quadrupole polarities and well corresponds to the X-shaped structure. After the jet eruption, the temperature and emission measure of the plasma near the X-shaped structure rise from ...

  3. Dynamical Mean-Field Theory Plus Numerical Renormalization-Group Study of Spin-Orbital Separation in a Three-Band Hund Metal.

    Science.gov (United States)

    Stadler, K M; Yin, Z P; von Delft, J; Kotliar, G; Weichselbaum, A

    2015-09-25

    We show that the numerical renormalization group is a viable multi-band impurity solver for dynamical mean-field theory (DMFT), offering unprecedented real-frequency spectral resolution at arbitrarily low energies and temperatures. We use it to obtain a numerically exact DMFT solution to the Hund metal problem for a three-band model on a Bethe lattice at 1/3 filling. The ground state is a Fermi liquid. The one-particle spectral function undergoes a coherence-incoherence crossover with increasing temperature, with spectral weight being transferred from low to high energies. Further, it exhibits a strong particle-hole asymmetry. In the incoherent regime, the self-energy displays approximate power-law behavior for positive frequencies only. The spin and orbital spectral functions show "spin-orbital separation": spin screening occurs at much lower energies than orbital screening. The renormalization group flows clearly reveal the relevant physics at all energy scales.

  4. Thermal Balance of the Magneto-Hydro-Dynamic Pump for Recovery of Platinum Group Metals from Spent Auto Catalysts

    Directory of Open Access Journals (Sweden)

    Gil S.

    2016-03-01

    Full Text Available Every new car should be equipped with the catalyst, which limits the amount of harmful chemical compounds such as NOx, CH and CO emitted to the air. Auto catalyst consists of the ceramic or metallic carrier, on which is the layer with Platinum Group Metals playing catalytic role. There are many methods using for recovery those valuable metals from spent auto catalyst, however evry of those methods have some limitations. Proces described in the article is the modified method of metal collector, which used magnetohydrodynamic pump. Rotary electromagnetic field generates in the liquid metal rotary current, which as a consequence washing out the PGM metals from the ceramic carriers. Considering the possibilities of commercialization of the described method, the energy balance was made. From that balance the energetic efficiency of the unit was determined and the analysis of the temperature distribution was shown thermographycally.

  5. Real-time density matrix renormalization group dynamics of spin and charge transport in push-pull polyenes and related systems

    Science.gov (United States)

    Dutta, Tirthankar; Ramasesha, S.

    2012-01-01

    In this paper we investigate the effect of terminal substituents on the dynamics of spin and charge transport in donor-acceptor substituted polyenes [D-(CH)x-A] chains, also known as push-pull polyenes. We employ a long-range correlated model Hamiltonian for the D-(CH)x-A system, and time-dependent density matrix renormalization group technique for time propagating the wave packet obtained by injecting a hole at a terminal site, in the ground state of the system. Our studies reveal that the end groups do not affect spin and charge velocities in any significant way, but change the amount of charge transported. We have compared these push-pull systems with donor-acceptor substituted polymethine imine (PMI), D-(CHN)x-A, systems in which besides electron affinities, the nature of pz orbitals in conjugation also alternate from site to site. We note that spin and charge dynamics in the PMIs are very different from that observed in the case of push-pull polyenes, and within the time scale of our studies, transport of spin and charge leads to the formation of a “quasi-static” state.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Group play

    DEFF Research Database (Denmark)

    Tychsen, Anders; Hitchens, Michael; Brolund, Thea

    2008-01-01

    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......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...

  11. Group typicality, group loyalty and cognitive development.

    Science.gov (United States)

    Patterson, Meagan M

    2014-09-01

    Over the course of childhood, children's thinking about social groups changes in a variety of ways. Developmental Subjective Group Dynamics (DSGD) theory emphasizes children's understanding of the importance of conforming to group norms. Abrams et al.'s study, which uses DSGD theory as a framework, demonstrates the social cognitive skills underlying young elementary school children's thinking about group norms. Future research on children's thinking about groups and group norms should explore additional elements of this topic, including aspects of typicality beyond loyalty.

  12. Dynamics of the indicators of physical development, physical and technical fitness of young 12 - 15 year old weightlifters of the different groups of weight categories

    Directory of Open Access Journals (Sweden)

    Lutovinov Iu.A.

    2012-11-01

    Full Text Available Here is the dynamics of indicators of physical development, physical and technical preparedness of young 12 - 15 year old weightlifters who are training for the Championship of Ukraine. 50 sportsman's has taken part in investigation. Age of sportsman - 12 - 15 years old. The indicators of physical development and preparedness of sportsmen were researched. The indicators of physical preparedness in control snatch, clean and jerk exercises were analyzed. The interconnection among the indicators of physical development as well as general and special physical preparedness of young weightlifters was shown. It was analyzed that the body length indicators of sportsmen are tend to grow by 15.2 % with an increase of weight category groups. It was estimated that the index of active mass of sportsman body grows by 14.2% with an increase of weight category groups. It was analyzed that the length indicators of upper and low extremities of young weightlifters grow on average by 14.6% and 15.1% with an increase of weight category groups. It was estimated that the indicators of general and special physical preparedness of young weightlifters grow on average by 18.2% and 40.8%.

  13. Hydrocarbons depending on the chain length and head group adopt different conformations within a water-soluble nanocapsule: 1H NMR and molecular dynamics studies.

    Science.gov (United States)

    Choudhury, Rajib; Barman, Arghya; Prabhakar, Rajeev; Ramamurthy, V

    2013-01-10

    In this study we have examined the conformational preference of phenyl-substituted hydrocarbons (alkanes, alkenes, and alkynes) of different chain lengths included within a confined space provided by a molecular capsule made of two host cavitands known by the trivial name "octa acid" (OA). One- and two-dimensional (1)H NMR experiments and molecular dynamics (MD) simulations were employed to probe the location and conformation of hydrocarbons within the OA capsule. In general, small hydrocarbons adopted a linear conformation while longer ones preferred a folded conformation. In addition, the extent of folding and the location of the end groups (methyl and phenyl) were dependent on the group (H(2)C-CH(2), HC═CH, and C≡C) adjacent to the phenyl group. In addition, the rotational mobility of the hydrocarbons within the capsule varied; for example, while phenylated alkanes tumbled freely, phenylated alkenes and alkynes resisted such a motion at room temperature. Combined NMR and MD simulation studies have confirmed that molecules could adopt conformations within confined spaces different from that in solution, opening opportunities to modulate chemical behavior of guest molecules.

  14. Capturing Earth Science Learning Dynamics: Communication Interactions of ESE Teachers and Children Occurring in Online, Classroom, and Small-Group Environments.

    Science.gov (United States)

    Snyder, C. W.; Prince, B. L.

    2002-12-01

    While the processes of schooling in science are usually measured in the resulting skills and products that students acquire or generate, another way to understand science learning is to explore the interactions and discourse that occur during actual learning activities. To investigate the dynamics of inquiry-based learning of earth science, we have explored the patterns that emerge in several learning environments: when teachers create dialog with other teachers in online ESE courses; when they teach earth science lessons in their classrooms; when they discuss their teaching perspectives in interviews; and when small groups of children engage in learning earth science together. By observing and scoring lesson exchanges, preserving online discussions, and documenting words and interactions in audio or video recordings, we are able to distinguish communication configurations that occur when teachers and children engage in the learning of earth science that would otherwise be invisible.

  15. 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).

  16. Bridging the gap from ocean models to population dynamics of large marine predators: A model of mid-trophic functional groups

    Science.gov (United States)

    Lehodey, Patrick; Murtugudde, Raghu; Senina, Inna

    2010-01-01

    The modeling of mid-trophic organisms of the pelagic ecosystem is a critical step in linking the coupled physical-biogeochemical models to population dynamics of large pelagic predators. Here, we provide an example of a modeling approach with definitions of several pelagic mid-trophic functional groups. This application includes six different groups characterized by their vertical behavior, i.e., occurrence of diel migration between epipelagic, mesopelagic and bathypelagic layers. Parameterization of the dynamics of these components is based on a temperature-linked time development relationship. Estimated parameters of this relationship are close to those predicted by a model based on a theoretical description of the allocation of metabolic energy at the cellular level, and that predicts a species metabolic rate in terms of its body mass and temperature. Then, a simple energy transfer from primary production is used, justified by the existence of constant slopes in log-log biomass size spectrum relationships. Recruitment, ageing, mortality and passive transport with horizontal currents, taking into account vertical behavior of organisms, are modeled by a system of advection-diffusion-reaction equations. Temperature and currents averaged in each vertical layer are provided independently by an Ocean General Circulation Model and used to drive the mid-trophic level (MTL) model. Simulation outputs are presented for the tropical Pacific Ocean to illustrate how different temperature and oceanic circulation conditions result in spatial and temporal lags between regions of high primary production and regions of aggregation of mid-trophic biomass. Predicted biomasses are compared against available data. Data requirements to evaluate outputs of these types of models are discussed, as well as the prospects that they offer both for ecosystem models of lower and upper trophic levels.

  17. Dynamic of functional microbial groups during mesophilic composting of agro-industrial wastes and free-living (N2)-fixing bacteria application.

    Science.gov (United States)

    Pepe, Olimpia; Ventorino, Valeria; Blaiotta, Giuseppe

    2013-07-01

    Although several reports are available concerning the composition and dynamics of the microflora during the composting of municipal solid wastes, little is known about the microbial diversity during the composting of agro-industrial refuse. For this reason, the first parts of this study included the quantification of microbial generic groups and of the main functional groups of C and N cycle during composting of agro-industrial refuse. After a generalized decrease observed during the initial phases, a new bacterial growth was observed in the final phase of the process. Ammonifiers and (N2)-fixing aerobic groups predominated outside of the piles whereas, nitrate-reducing group increased inside the piles during the first 23days of composting. Ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB), showed an opposite trend of growth since ammonia oxidation decreased with the increase of the nitrite oxidation activity. Pectinolytics, amylolytics and aerobic cellulolytic were present in greater quantities and showed an upward trend in both the internal and external part of the heaps. Several free-living (N2)-fixing bacteria were molecularly identify as belonging especially to uncommon genera of nitrogen-fixing bacteria as Stenotrophomonas, Xanthomonas, Pseudomonas, Klebsiella, Alcaligenes, Achromobacter and Caulobacter. They were investigated for their ability to fix atmospheric nitrogen to employ as improvers of quality of compost. Some strains of Azotobacter chrococcum and Azotobacter salinestris were also tested. When different diazotrophic bacterial species were added in compost, the increase of total N ranged from 16% to 27% depending on the selected microbial strain being used. Such microorganisms may be used alone or in mixtures to provide an allocation of plant growth promoting rhizobacteria in soil. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Dinamiche di manipolazione mentale ed organizzazioni di stampo mafioso / Dynamiques de manipulation mentale et organisations criminelles de type mafieux / Dynamics of mental manipulation and Mafia groups

    Directory of Open Access Journals (Sweden)

    Pomilla A.

    2010-12-01

    Full Text Available Questo articolo si focalizza sull’analisi delle dinamiche di manipolazione mentale che i gruppi mafiosi esercitano sui propri affiliati, in grado di determinare progressivi vincoli morali non già in virtù delle attività criminose che verranno poi svolte, bensì in relazione alle rappresentazioni mentali che gli stessi hanno verso di sé in quanto appartenenti a tale gruppo. Verranno quindi descritte le rappresentazioni mentali che gli affiliati hanno di se stessi, nonché quelle provenienti dalle disamine interpretative esterne. Verrà inoltre illustrato il “pensiero mafioso” quale profonda ed inconscia modalità ideativa che caratterizza il “gruppo mafia” con valori più saldi e forti di quelli familiari ed in virtù della quale si determinano proprio quei meccanismi di svincolo morale che sostanziano la dimensione criminologica delle organizzazioni di stampo mafioso.Cet article se concentre sur l'analyse des dynamiques de manipulation mentale que les groupes mafieux exercent sur leurs affiliés, des dynamiques capables de susciter un désinvestissement moral progressif, non pas lié aux activités criminelles qui seront développées par la suite, mais en relation avec les représentations mentales que les individus ont d’eux-mêmes, en tant que membres d’un tel groupe. Ainsi, nous décrirons les représentations mentales que les membres ont d’eux-mêmes, ainsi que celles tirées des analyses interprétatives externes. De plus, nous illustrerons « la pensée mafieuse » en tant que modalité idéative profonde et inconsciente qui caractérise « le groupe mafieux » marqué (et soudé par des valeurs plus solides et plus fortes que celles issues du milieu familial et grâce auxquelles se déterminent ces mécanismes de désinvestissement moral qui caractérisent la dimension criminologique des organisations de type mafieux.This article analyses the dynamics of mental manipulation that the Mafia groups impose on their own

  19. 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.

  20. Extreme expansion of the olfactory receptor gene repertoire in African elephants and evolutionary dynamics of orthologous gene groups in 13 placental mammals.

    Science.gov (United States)

    Niimura, Yoshihito; Matsui, Atsushi; Touhara, Kazushige

    2014-09-01

    Olfactory receptors (ORs) detect odors in the environment, and OR genes constitute the largest multigene family in mammals. Numbers of OR genes vary greatly among species--reflecting the respective species' lifestyles--and this variation is caused by frequent gene gains and losses during evolution. However, whether the extent of gene gains/losses varies among individual gene lineages and what might generate such variation is unknown. To answer these questions, we used a newly developed phylogeny-based method to classify >10,000 intact OR genes from 13 placental mammal species into 781 orthologous gene groups (OGGs); we then compared the OGGs. Interestingly, African elephants had a surprisingly large repertoire (∼ 2000) of functional OR genes encoded in enlarged gene clusters. Additionally, OR gene lineages that experienced more gene duplication had weaker purifying selection, and Class II OR genes have evolved more dynamically than those in Class I. Some OGGs were highly expanded in a lineage-specific manner, while only three OGGs showed complete one-to-one orthology among the 13 species without any gene gains/losses. These three OGGs also exhibited highly conserved amino acid sequences; therefore, ORs in these OGGs may have physiologically important functions common to every placental mammal. This study provides a basis for inferring OR functions from evolutionary trajectory. © 2014 Niimura et al.; Published by Cold Spring Harbor Laboratory Press.

  1. Identification of Novel Proteins Co-Purifying with Cockayne Syndrome Group B (CSB) Reveals Potential Roles for CSB in RNA Metabolism and Chromatin Dynamics.

    Science.gov (United States)

    Nicolai, Serena; Filippi, Silvia; Caputo, Manuela; Cipak, Lubos; Gregan, Juraj; Ammerer, Gustav; Frontini, Mattia; Willems, Daniela; Prantera, Giorgio; Balajee, Adayabalam S; Proietti-De-Santis, Luca

    2015-01-01

    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.

  2. 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%.

  3. BASIN DYNAMICS AND BASIN GROUPS OF THE SOUTH CHINA SEA%南海的盆地群与盆地动力学

    Institute of Scientific and Technical Information of China (English)

    李三忠; 安慧婷; 薛友辰; 熊莉娟; 曹现志; 许立青; 索艳慧; 刘鑫; 戴黎明; 余珊; 赵淑娟; 马云; 王霄飞; 程世秀

    2012-01-01

    The South China Sea was formed in Cenozoic. Basins in the South China Sea could be divided into different types, such as continental shelf basins, continental slope basins and deep sea basins, which are closely related with the rifting and transition of the continental margins, and thus could be grouped into strike-slip-related pull-apart and extensional basins, extrusion-escape-related rifting basins, extension- and subduction-related buckling basins. They developed further into some ndge-spreading-related oceanic sub-basins in different stages. These basins were formed not under a single dynamics but under a very complex and changeable dynamics. These basins have suffered from a series of Cenozoic tectonic movements, such as the Shenhu, the South China Sea, the Dongsha, resulting in the formation and spatial-temperal migration of complex angular unconformities in these basins. Accompanying with the tectonic migrations and evolutions in these basins, faulting, magmatism, shifting of sedimentary subsidence centers and depo-centers, oil accumulation and geohazards show a significant feature of jumping. The complex dynamic settings of the South China Sea have caused many controversies on their origin. The plate dynamic factors include the Pacific Plate subduction and the indentation of the Philippine Sea Plate along the Taiwan Orogen to the east side of the South China Sea, and the Indian Plate oblique subduction and mid-ocean ridge subduction to the west side. They may also be responsible for the uplifting of the Tibetan Plateau and the related extrusions of continental blocks to the north side. At the same time, the mantle dynamics of deep-seated magma underplating, delamination, mantle plume and mantle-hydrated process should not be ignored. At last, this paper proposes one strike-slipping pull-apart model to explain the onset of the South China Sea Basin which is closely related to the tectonic evolution of the Pacific Tectonic Domain.%南海发育有众多的

  4. Dynamic Analysis of Industrial Robot Using Lie Groups%基于李群方法的6自由度机器人机构动力学分析

    Institute of Scientific and Technical Information of China (English)

    刘会英; 杨彩君; 刘博宇

    2011-01-01

    The 6-DOF robot mechanism dynamic equation is described with Lie group. Explicit connections between the equations of motion and concepts from Lie theory are established. First, the transformation is described by the exponential map, which can also describes the position and pose of the robot. The adjoint representation of the Lie group and the Lie algebra is used to describe the generalized velocity and acceleration. The final dynamic equation is obtained in recursive form. Then Matlab program is developed to solve dynamic equation, when 100Nm working torque is loaded on the wrist, the driving moment dynamic characteristics of each joint is obtained. At last, we use MSC Adams to emulate the robot model, the results of Adams coincide with that of the Lie group method. So, the Lie group method in robot dynamics is effective, espetcially in complex situation.%用李群李代数建立了六自由度机器人的机构动力学方程,描述了机器人的位姿及相应的速度和加速度.并对六自由度工业机器人进行了Matlab仿真与Adams验证,应用李群推法得到了关节驱动力矩与根据Adams分析所得的关节驱动力矩具有很好的一致性,误差为5%.说明了李群方法在机器人动力学分析中的适用性.

  5. Do the Teacher and School Factors of the Dynamic Model Affect High- and Low-Achieving Student Groups to the Same Extent? A Cross-Country Study

    Science.gov (United States)

    Vanlaar, Gudrun; Kyriakides, Leonidas; Panayiotou, Anastasia; Vandecandelaere, Machteld; McMahon, Léan; De Fraine, Bieke; Van Damme, Jan

    2016-01-01

    Background: The dynamic model of educational effectiveness (DMEE) is a comprehensive theoretical framework including factors that are important for school learning, based on consistent findings within educational effectiveness research. Purpose: This study investigates the impact of teacher and school factors of DMEE on mathematics and science…

  6. Was the Group Dynamic Phenomenon Groupthink Present on Board the USS Greeneville (SSN-772) When She Collided with the Japanese Fishing Vessel Ehime Maru?

    Science.gov (United States)

    2007-11-02

    group as a whole ( Durkheim 1928, 128-129). Most sociologists believe that it is not necessary to study the individuals because the group is the true...Cambridge, MA: Perseus Books. Durkheim , E. 1928. The rules of sociological method. New York: The Free Press. Eagly, A. H. 1987. Sex differences in social

  7. [Vertical distribution and quantitative dynamics of dominant functional groups of arthropod community in rice fields and estimation of natural enemy effects].

    Science.gov (United States)

    Hao, S; Zhang, X; Cheng, X

    2000-02-01

    The study showed that Lycosid (wolf spider) mainly distributed in the basal part of rice plants, not as wide as we know in past. Tetragnathid did not limited in the upper part of plants, but might translate to middle or lower part when affected by insecticide. The relationship between the vertical distributions of top and basal species was not significant. Besides the amount of natural enemies, the spatial distribution characteristics of natural enemies and brownplanthopper, and the proportion of brownplanthopper to total preys of natural enemies were the factors affecting the role of natural enemies on the population dynamics of brownplanthopper in rice fields. A model to evaluate the effect of natural enemies to brownplanthopper was put forward, which included the message of quantitative dynamics, spatial distribution and feeding characteristics of natural enemies, brownplanthopper and neutral insects.

  8. STUDY OF THE DYNAMIC OF HELICOBACTER PYLORI INFECTION PREVALENCE IN DIFFERENT AGE GROUPS OF ST. PETERSBURG POPULATION IN 2007-2011

    Directory of Open Access Journals (Sweden)

    A. V. Svarval

    2012-01-01

    Full Text Available Abstract. Presence of specific antibodies to H. pylori and to its Cag A toxin was studied in 1917 persons, including 860 children and 1057 adults, in Pasteur Research Institute of Epidemiology and Microbiology, St. Petersburg, Russia. The studied group was presented by the subjectively healthy individuals and blood donors living in St. Petersburg. The growth and stabilization of serological positive rates to H. pilory at high level, as well as increasing the proportion of CagA-positive infection among children and adults in St. Petersburg in 2007–2011 have been established. There are 3 age risk groups of H. pylori infection among children population: 4–5 years, 7–8 years and 14–15 years. The shift of the maximum H. pylori seropositivity rates from age group of 30–39 years in 2007 to age group 40–49 years in 2011 was detected.

  9. Group Psychotherapy in Iceland.

    Science.gov (United States)

    Ívarsson, Ómar

    2015-10-01

    In this overview of group psychotherapy in Iceland, an attempt will be made to describe how it is practiced today, give some glimpses into its earlier history, and clarify seven issues: (1) the standing of group psychotherapy in Iceland, its previous history, and the theoretical orientation of dynamic group therapy in the country; (2) the role of group therapy in the health care system; (3) how training in group therapy is organized; (4) the relationship between group psychotherapy research and clinical practice; (5) which issues/processes can be identified as unique to therapy groups in Iceland; and (6) how important are group-related issues within the social background of the country; and (7) what group work holds for the future.

  10. Molecular assessment of Hepatozoon (Apicomplexa: Adeleorina) infections in wild canids and rodents from north Africa, with implications for transmission dynamics across taxonomic groups.

    Science.gov (United States)

    Maia, João P; Alvares, Francisco; Boratyński, Zbyszek; Brito, José C; Leite, João V; Harris, D James

    2014-10-01

    Parasites play a major role in ecosystems, and understanding of host-parasite interactions is important for predicting parasite transmission dynamics and epidemiology. However, there is still a lack of knowledge about the distribution, diversity, and impact of parasites in wildlife, especially from remote areas. Hepatozoon is a genus of apicomplexan parasites that is transmitted by ingestion of infected arthropod vectors. However, alternative modes of transmission have been identified such as trophic transmission. Using the 18S rRNA gene as a marker, we provide an assessment of Hepatozoon prevalence in six wild canid and two rodent species collected between 2003 and 2012 from remote areas in North Africa. By combining this with other predator-prey systems in a phylogenetic framework, we investigate Hepatozoon transmission dynamics in distinct host taxa. Prevalence was high overall among host species (African jerboa Jaculus jaculus [17/47, 36%], greater Egyptian jerboa Jaculus orientalis [5/7, 71%], side-striped jackal Canis adustus [1/2, 50%], golden jackal Canis aureus [6/32, 18%], pale fox Vulpes pallida [14/28, 50%], Rüppell's fox Vulpes rueppellii [6/11, 55%], red fox Vulpes vulpes [8/16, 50%], and fennec fox Vulpes zerda [7/11, 42%]). Phylogenetic analysis showed further evidence of occasional transmission of Hepatozoon lineages from prey to canid predators, which seems to occur less frequently than in other predator-prey systems such as between snakes and lizards. Due to the complex nature of the Hepatozoon lifecycle (heteroxenous and vector-borne), future studies on these wild host species need to clarify the dynamics of alternative modes of Hepatozoon transmission and identify reservoir and definitive hosts in natural populations. We also detected putative Babesia spp. (Apicomplexa: Piroplasmida) infections in two canid species from this region, V. pallida (1/28) and V. zerda (1/11).

  11. Groups of Circle Diffeomorphisms

    CERN Document Server

    Navas, Andrés

    2011-01-01

    In recent years scholars from a variety of branches of mathematics have made several significant developments in the theory of group actions. Groups of Circle Diffeomorphisms systematically explores group actions on the simplest closed manifold, the circle. As the group of circle diffeomorphisms is an important subject in modern mathematics, this book will be of interest to those doing research in group theory, dynamical systems, low dimensional geometry and topology, and foliation theory. The book is mostly self-contained and also includes numerous complementary exercises, making it an excell

  12. 大学生团体心理气氛及疗效因子的变化--动力取向人际关系团体心理咨询%Change of Group Climate and Therapeutic Factor in Dynamically Interpersonal Groups of College Students

    Institute of Scientific and Technical Information of China (English)

    王海荣; 赵冰洁

    2015-01-01

    The objective of this study is dynamically interpersonal group therapy to college students as the research subject. The purpose is to find the change of the group climate and the therapeutic factors in the dynamically interpersonal group psychotherapy. The method is to measure student group in early and late stage with climate questionnaire and therapeutic factor questionnaire. The results are: compared with that of the late stage, the engagement of group climate is low, the conflict and avoidance are high in early stage. The therapeutic factors that play more important role are catharsis, self-understanding and guidance in early stage. As the group process, the engagement of group climate is elated, the conflict and avoidance reduced in late stage. The therapeutic factors that play more important role are self-understanding, family reproduction and interpersonal input in late stage. At the same time in the early and late group, there is significant difference in terms of the therapeutic factors of altruism, interpersonal input, family reproduction and self-understanding. The conclusion is: dynamically college students interpersonal groups are different group climate and therapeutic factors in early and late stage.%目的:主要探讨动力取向大学生团体咨询气氛和疗效因子的变化。方法:运用团体气氛量表和疗效因素量表对团体施测。结果:经比较分析,早期气氛投入度低,冲突度和逃避度较高,晚期投入度升高,冲突度、逃避度下降;利他性、人际觉察、家庭重现、自我了解等因子有差异;与早期相比,晚期投入度高的气氛下,自我了解、家庭重现、人际觉察为重要疗效因子。结论:动力取向的大学生团体心理咨询早期和晚期气氛与疗效因子不同。

  13. Conformational Analysis of Indole Alkaloids Corynantheine and Dihydrocorynantheine by Dynamic 1H NMR Spectroscopy and Computational Methods: Steric Effects of Ethyl vs Vinyl Group

    DEFF Research Database (Denmark)

    Stærk, Dan; Norrby, Per-Ola; Jaroszewski, Jerzy W.

    2001-01-01

    . Line-shape analysis yielded enthalpy of activation DeltaH(double dagger) = 71 +/- 6 kJ/mol, and entropy of activation DeltaS(double dagger) = 33 +/- 6 J/mol(.)K. The major and minor conformation contains the methyl ether group above and below the plane of the ring, respectively, as determined by low...... bulk of the vinyl and the ethyl group. The conformational equilibria involving the side chain rotation as well as inversion of the bridgehead nitrogen in corynantheine and dihydrocorynantheine was studied by force-field (Amber(*) and MMFF) and ab initio (density-functional theory at the B3LYP/6-31G...

  14. Effects of extreme seasonality on community structure and functional group dynamics of coral reef algae in the southern Red Sea (Eritrea)

    NARCIS (Netherlands)

    Ateweberhan, M.; Bruggemann, J. H.; Breeman, A. M.

    Spatial and temporal variation in the biomass of four functional groups of coral reef algae (canopy algae, foliose algae, turf algae and crustose corallines) was investigated in the southern Red Sea. This region is characterised by extremely high summer temperatures (ca. 35 degrees C). Strong

  15. Effects of extreme seasonality on community structure and functional group dynamics of coral reef algae in the southern Red Sea (Eritrea)

    NARCIS (Netherlands)

    Ateweberhan, M.; Bruggemann, J. H.; Breeman, A. M.

    2006-01-01

    Spatial and temporal variation in the biomass of four functional groups of coral reef algae (canopy algae, foliose algae, turf algae and crustose corallines) was investigated in the southern Red Sea. This region is characterised by extremely high summer temperatures (ca. 35 degrees C). Strong season

  16. 基于动态博弈的网络联保贷款模式发展策略研究%Research on Network Group Lending Development Strategy based on Dynamic Game

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    The network group lending has a good foundation to service for SME, through constructing network group lending model of dynamic game analysis framework in the small and micro enterprises and contrasting group lending with network group lending, the paper found the advantage of developing network group lending is to establish effective incen-tive and punishment mechanism in market closed environment;the key of developing the network group lending is how to combine financial institutions and e-commerce platform, and provide quality credit services.%网络联保贷款具有服务小微企业的良好基础,通过构建面向小微企业网络联保贷款模式的动态博弈分析框架,本文对联保贷款与网络联保贷款进行博弈分析,发现在市场封闭的环境下发展网络联保贷款的优势在于建立有效的激励与惩罚机制,网络联保贷款发展的关键在于金融机构与电子商务平台如何有机结合,并为服务对象提供优质的信贷服务。

  17. Dynamics of the separation of amino acid and mineral salt in the stationary dialysis of solutions with an MK-40 profiled sulfo group cation exchange membrane

    Science.gov (United States)

    Vasil'eva, V. I.; Vorob'eva, E. A.

    2012-11-01

    The conjugated diffusion transport of amino acid and mineral salt through a profiled sulfo group cation exchange membrane that simulates the extraction of amino acid from wash waters of microbiological production containing mineral components not used in synthesis is studied. The competitive nature of the conjugation of flows resulting in a decrease in the rate of the mass transfer of components and their separation factor is established from a comparative analysis of experimental data on the diffusion transfer of phenylalanine and sodium chloride in the form of hydrogen from individual and mixed solutions through a profiled sulfo group cation exchange membrane. The range of concentrations and the ratio of components in solution corresponding to the effective separation of phenylalanine and sodium chloride are determined.

  18. STUDY OF THE DYNAMIC OF HELICOBACTER PYLORI INFECTION PREVALENCE IN DIFFERENT AGE GROUPS OF ST. PETERSBURG POPULATION IN 2007-2011

    OpenAIRE

    A. V. Svarval; R. S. Ferman; A. B. Zhebrun

    2012-01-01

    Abstract. Presence of specific antibodies to H. pylori and to its Cag A toxin was studied in 1917 persons, including 860 children and 1057 adults, in Pasteur Research Institute of Epidemiology and Microbiology, St. Petersburg, Russia. The studied group was presented by the subjectively healthy individuals and blood donors living in St. Petersburg. The growth and stabilization of serological positive rates to H. pilory at high level, as well as increasing the proportion of CagA-positive infect...

  19. Influence of the number of blades in the dynamic behavior of groups; Influencia del numero de alabes en el comportamiento dinamico de grupos

    Energy Technology Data Exchange (ETDEWEB)

    Yrigoyen Lazzeri, Oscar [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1986-12-31

    In this article a research is made of the change of natural frequencies of groups formed by different number of blades. To estimate the natural frequencies and the vibration modes, the finite element is used, modeling real blades with beam elements. The models employed represent groups of two to ten blades tied up together by two dampening wires and an external belt, also modeled with beam elements . The angular rigidities at the intersection between the blades and the dampening wires and with the external belt were simulated with border elements. The analytical results were compared with laboratory and field values for a single blade and a group of ten blades. [Espanol] En este articulo se investiga el cambio de frecuencias naturales en grupos formados por diferente numero de alabes. Para calcular las frecuencias naturales y los modos de vibracion, se utiliza el metodo del elemento finito, modelando alabes reales con elementos viga. Los modelos utilizados representan grupos de dos a diez alabes unidos por dos alambres amortiguadores y un cinturon externo. Los alambres amortiguadores y el cinturon externo tambien se modelaron con elementos viga. Las rigideces angulares en los puntos de interseccion entre los alabes con los alambres amortiguadores y con el cinturon externo se simularon con elementos frontera. Se comparan resultados analiticos con valores de laboratorio y de campo para un alabe sencillo y un grupo de diez alabes.

  20. Group X

    Energy Technology Data Exchange (ETDEWEB)

    Fields, Susannah

    2007-08-16

    This project is currently under contract for research through the Department of Homeland Security until 2011. The group I was responsible for studying has to remain confidential so as not to affect the current project. All dates, reference links and authors, and other distinguishing characteristics of the original group have been removed from this report. All references to the name of this group or the individual splinter groups has been changed to 'Group X'. I have been collecting texts from a variety of sources intended for the use of recruiting and radicalizing members for Group X splinter groups for the purpose of researching the motivation and intent of leaders of those groups and their influence over the likelihood of group radicalization. This work included visiting many Group X websites to find information on splinter group leaders and finding their statements to new and old members. This proved difficult because the splinter groups of Group X are united in beliefs, but differ in public opinion. They are eager to tear each other down, prove their superiority, and yet remain anonymous. After a few weeks of intense searching, a list of eight recruiting texts and eight radicalizing texts from a variety of Group X leaders were compiled.

  1. Vibrational spectroscopic and thermo dynamical property studies, Fukui functions, HOMO-LUMO, NLO, NBO and crystal structure analysis of a new Schiff base bearing phenoxy-imine group

    Science.gov (United States)

    Ceylan, Ümit; Çapan, Ali; Yalçın, Şerife Pınar; Sönmez, Mehmet; Aygün, Muhittin

    2017-05-01

    This study covers the synthesis, structural characterization by experimental FT-IR, 1H NMR and 13C NMR, UV-Vis and single crystal XRD and comparison with theoretical calculations of a Schiff base compound bearing phenoxy group, C34H28N2O4 by using the DFT method 6-311G(d,p) basis set. The molecular geometry, the dipole moments, electrostatic potential, vibrational frequencies, HOMO-LUMO energy were calculated. NBO, NLO, thermodynamic properties and Fukui function were studied. In this work, theoretical values show good agreement with experimental values.

  2. Dynamic polarization of protons in 2,3-butanediol doped with Cr(V)- complex and in other materials containing adjacent hydroxyl groups

    CERN Document Server

    Guckelsberger, K

    1977-01-01

    Results are given on 2,3-butanediol doped with Cr(V)-complex as a material for polarized proton targets. It is shown to be an improvement over the presently used 1,2-propanediol since its chemical composition is slightly more favourable and its melting point is near room temperature. Maximum polarization, nuclear relaxation time, reversal time, minimum power requirement, radiation resistance, and annealing temperature are all very similar to 1,2-propanediol. A review of other materials containing adjacent hydroxyl groups is made, and conclusions are drawn as to their possible use as target materials. (17 refs).

  3. Approach for dynamic group automatic aggregation path planning based on improved FA%基于改进萤火虫算法的动态自动聚集路径规划方法

    Institute of Scientific and Technical Information of China (English)

    刘鹏; 刘弘; 郑向伟; 丁艳辉

    2011-01-01

    针对群体动画中自动聚集场景的特点及现有方法中存在的计算代价高、行为单一、逼真程度不够、缺乏涌现特征的不足,提出了基于改进萤火虫算法的群体动态自动聚集路径规划方法.在群体自动聚集过程中,不但无须提前指定聚集目标点,而且根据外界环境的动态变化,自动寻找最优的聚集目标点.通过该方法可以为每个粒子生成运动路径,并能保证每次生成的聚集路径不完全一致,使制作的群体动画体现出群体运动的涌现特征,有效地提高群体动画的逼真效果.通过所开发的动态自动聚集路径规划系统有效地模拟群体聚集行为,验证了本方法的可行性和有效性.%Aiming at the features of automatic aggregation scene in group animation and the existing methods in the presence of high computational cost, the lack of diversity in a single act, realistic level, lack of emergence of features, this paper proposed an approach for path-planning of crowd dynamic automatic aggregation based on improved firefly algorithms. In the process of achieving the automatic aggregation of crowd, it was not only unnecessary to designate the target point of aggregation , but also could according to the dynamic changes in the external environment, the optimal target point of aggregation could be found automatically . The motion path of each particle could be generated in this approach, which could guarantee that each generated path was not exactly the same so that the produced group animation could fully reflect the features of crowd movement in reality and improve the lifelike effects of group animation effectively. Developed a system for path planning of dynamic automatic aggregation, and the experiments in the system show that the proposed approach can achieve the effects of dynamic automatic aggregation and simulate the group behavior effectively, demonstrating the feasibility and effectiveness of this method.

  4. E-groups training

    CERN Multimedia

    HR Department

    2012-01-01

    There will be an e-groups training course on 16 March 2012 which will cover the main e-groups functionalities i.e.: creating and managing e-groups, difference between static and dynamic e-groups, configuring posting restrictions and archives, examples of where e-groups can be used in daily work. Even if you have already worked with e-groups, this may be a good opportunity to learn about the best practices and security related recommendations when using e-groups. You can find more details as well as enrolment form for the training (it’s free) here. The number of places is limited, so enrolling early is recommended.   Technical Training Tel. 72844

  5. Group morphology

    NARCIS (Netherlands)

    Roerdink, Jos B.T.M.

    2000-01-01

    In its original form, mathematical morphology is a theory of binary image transformations which are invariant under the group of Euclidean translations. This paper surveys and extends constructions of morphological operators which are invariant under a more general group TT, such as the motion group

  6. Can dispersion corrections annihilate the dispersion-driven nano-aggregation of non-polar groups? An ab initio molecular dynamics study of ionic liquid systems.

    Science.gov (United States)

    Firaha, Dzmitry S; Thomas, Martin; Hollóczki, Oldamur; Korth, Martin; Kirchner, Barbara

    2016-11-28

    In this study, we aim at understanding the influence of dispersion correction on the ab initio molecular dynamics simulations of ionic liquid (IL) systems. We investigated a large bulk system of the 1-butyl-3-methylimidazolium triflate IL and a small cluster system of ethylamine in ethylammonium nitrate both under periodic boundary conditions. The large system displays several changes upon neglect of dispersion correction, the most striking one is the surprising decrease of the well-known microheterogeneity which is accompanied by an increase of side chain hydrogen atom-anion interplay. For the diffusion coefficient, we observe a correction towards experimental behavior in terms of the cation becoming faster than the anion with dispersion correction. Changes in the electronic structure upon dispersion correction are reflected in larger/smaller dipole moments for anions/cations also seen in the calculated IR spectrum. The energetics of different ion pair dimer subsystems (polar and non-polar) are in accordance with the analysis of the trajectories: A detailed balance in the ionic liquid system determines its particular behavior. While the overall interaction terms for dispersion-corrected calculations are higher, the decrease in microheterogeneity upon inclusion of dispersion interaction becomes obvious due to the relation between all contributions to polar-polar terms. For the small system, we clearly observe the well known behavior that the hybrid functionals show higher reaction barriers than the pure generalized gradient approximation (GGA) functionals. The correction of dispersion reduces the discrepancies in some cases. Accounting for the number of jumps, we observe that dispersion correction reduces the discrepancies from 50% to less than 10%.

  7. 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

  8. Can dispersion corrections annihilate the dispersion-driven nano-aggregation of non-polar groups? An ab initio molecular dynamics study of ionic liquid systems

    Science.gov (United States)

    Firaha, Dzmitry S.; Thomas, Martin; Hollóczki, Oldamur; Korth, Martin; Kirchner, Barbara

    2016-11-01

    In this study, we aim at understanding the influence of dispersion correction on the ab initio molecular dynamics simulations of ionic liquid (IL) systems. We investigated a large bulk system of the 1-butyl-3-methylimidazolium triflate IL and a small cluster system of ethylamine in ethylammonium nitrate both under periodic boundary conditions. The large system displays several changes upon neglect of dispersion correction, the most striking one is the surprising decrease of the well-known microheterogeneity which is accompanied by an increase of side chain hydrogen atom-anion interplay. For the diffusion coefficient, we observe a correction towards experimental behavior in terms of the cation becoming faster than the anion with dispersion correction. Changes in the electronic structure upon dispersion correction are reflected in larger/smaller dipole moments for anions/cations also seen in the calculated IR spectrum. The energetics of different ion pair dimer subsystems (polar and non-polar) are in accordance with the analysis of the trajectories: A detailed balance in the ionic liquid system determines its particular behavior. While the overall interaction terms for dispersion-corrected calculations are higher, the decrease in microheterogeneity upon inclusion of dispersion interaction becomes obvious due to the relation between all contributions to polar-polar terms. For the small system, we clearly observe the well known behavior that the hybrid functionals show higher reaction barriers than the pure generalized gradient approximation (GGA) functionals. The correction of dispersion reduces the discrepancies in some cases. Accounting for the number of jumps, we observe that dispersion correction reduces the discrepancies from 50% to less than 10%.

  9. Adult P. E. management innovation in view of group dynamics%群体动力学视域下成人体育教育管理创新

    Institute of Scientific and Technical Information of China (English)

    张旭敏

    2009-01-01

    The paper proposes to have correct understanding of the integrity of the harmonious interaction in the adult P. E. groups, abandon the egoism and optimize the management on the basis of the actual situation of the adult P. E.colleges so as to promote the Sustainable development of the adult P. E..%群体动力学的研究为协作学习的倡导者提供了重要启示,应正确认识成人体育教育群体和谐互动的整体性,抛弃以自我中心论,并结合各成人体育院校的实际情况,制定管理最优化措施,以促进成人体育教学各项工作稳定、可持续的发展.

  10. Group devaluation and group identification

    NARCIS (Netherlands)

    Leach, C.W.; Rodriguez Mosquera, P.M.; Vliek, M.L.W.; Hirt, E.

    2010-01-01

    In three studies, we showed that increased in-group identification after (perceived or actual) group devaluation is an assertion of a (preexisting) positive social identity that counters the negative social identity implied in societal devaluation. Two studies with real-world groups used order manip

  11. An Aggregation Method for Induction Motor Group and Its Testing With Dynamic Simulation%感应电动机群聚合方法及其动模试验

    Institute of Scientific and Technical Information of China (English)

    张红斌; 刘启玉; 刘应梅

    2011-01-01

    通过对感应电动机聚合理论进行研究,提出了一种感应电动机聚合方法:根据感应电动机2种特殊状态,即运行滑差s=0和s=1对感应电动机群进行等值,建立了感应电动机聚合模型.采用仿真准确度较高的动模试验验证了该等值方法的有效性和合理性.%Through the research on the aggregation of induction motor group, a new aggregation method for induction motor group is proposed. The equivalence of induction motor group is performed according to the two special operation states of induction motor, i.e., s=0 and s= 1, then an aggregation model of induction motor group is built. By means of dynamic simulation with higher accuracy, the effectiveness and reasonableness of the proposed equivalence are verified.

  12. Geometric group theory

    CERN Document Server

    Bestvina, Mladen; Vogtmann, Karen

    2014-01-01

    Geometric group theory refers to the study of discrete groups using tools from topology, geometry, dynamics and analysis. The field is evolving very rapidly and the present volume provides an introduction to and overview of various topics which have played critical roles in this evolution. The book contains lecture notes from courses given at the Park City Math Institute on Geometric Group Theory. The institute consists of a set of intensive short courses offered by leaders in the field, designed to introduce students to exciting, current research in mathematics. These lectures do not duplicate standard courses available elsewhere. The courses begin at an introductory level suitable for graduate students and lead up to currently active topics of research. The articles in this volume include introductions to CAT(0) cube complexes and groups, to modern small cancellation theory, to isometry groups of general CAT(0) spaces, and a discussion of nilpotent genus in the context of mapping class groups and CAT(0) gro...

  13. Evolutionary dynamics of the mitochondrial genome in the evaniomorpha (hymenoptera)—a group with an intermediate rate of gene rearrangement.

    Science.gov (United States)

    Mao, Meng; Gibson, Tracey; Dowton, Mark

    2014-07-01

    We determined the complete mitochondrial (mt) genomes of three evaniomorph species, Ceraphron sp. (Ceraphronoidea), Gasteruption sp. (Evanioidea), and Orthogonalys pulchella (Trigonalyoidea) as well as the nearly complete mt genome from another evaniomorph species, Megalyra sp. (Megalyroidea). Each of them possesses dramatic gene rearrangements, including protein-coding or rRNA genes. Gene inversions were identified in all of these mt genomes; for example, the two rRNA genes have inverted and moved into the nad2-cox1 junction in the Megalyra sp. mt genome. In addition, we found two copies of a 10-bp complementary repeat at the beginning of rrnS and at the end of trnL(2) in the Gasteruption sp. mt genome, consistent with recombination as the possible mechanism for gene inversion and long-range movement. Although each of the genomes contains a number of repeats of varying size, there was no consistent association of the size or number of repeats with the extent or type of gene rearrangement. The breakpoint distance analysis showed the Evaniomorpha has an intermediate rate of gene rearrangement. Sequence-based phylogenetic analyses of 13 protein-coding and 2 rRNA genes in 22 hymenopteran taxa recovered a paraphyletic Evaniomorpha with the Aculeata nested within it. Within the Evaniomorpha, our analyses confirmed the Trigonalyoidea + Megalyroidea as the sister group to the Aculeata and recovered a novel clade, Ceraphronoidea + Evanioidea. In contrast to previous hymenopteran phylogenetic studies, the internal relationships of the Evaniomorpha were highly supported and robust to the variation of alignment approach and phylogenetic inference approach.

  14. Ordered groups and topology

    CERN Document Server

    Clay, Adam

    2016-01-01

    This book deals with the connections between topology and ordered groups. It begins with a self-contained introduction to orderable groups and from there explores the interactions between orderability and objects in low-dimensional topology, such as knot theory, braid groups, and 3-manifolds, as well as groups of homeomorphisms and other topological structures. The book also addresses recent applications of orderability in the studies of codimension-one foliations and Heegaard-Floer homology. The use of topological methods in proving algebraic results is another feature of the book. The book was written to serve both as a textbook for graduate students, containing many exercises, and as a reference for researchers in topology, algebra, and dynamical systems. A basic background in group theory and topology is the only prerequisite for the reader.

  15. 基于ASP.NET的网站群动态建站技术研究%RESEARCH ON ASP.NET-BASED DYNAMIC WEBSITE CONSTRUCTION TECHNOLOGY FOR WEBSITE-GROUP

    Institute of Scientific and Technical Information of China (English)

    崔宝娟; 苏中滨; 沈维政

    2011-01-01

    Considering the problems of website-group system at present including integration difficulty between sub-website and main-website,information sharing and uniform management,this paper proposes a dynamic website contstruction method to create and manage the sub-website in website-group drnamically. Since both the sub-website and main-website are constructed with the uniform technology using same data structure and on same platform,it is convenient to integrate the resources of website-group, to share and to uniformly maintain the information among sub-websites ,this actually realizes the clustering management of the websites.%针对目前网站群系统中子站与主站整合困难、信息无法共享、难于统一管理的问题,提出了一种在网站群中动态建立子网站的方法,实现对子网站的动态创建和管理.由于子站与主站采用统一技术以相同的数据结构构建于同一平台,因此便于站群资源的整合和信息在各站间的共享与统一维护,真正实现了网站的集群化管理.

  16. Algebraic Groups

    DEFF Research Database (Denmark)

    2007-01-01

    The workshop continued a series of Oberwolfach meetings on algebraic groups, started in 1971 by Tonny Springer and Jacques Tits who both attended the present conference. This time, the organizers were Michel Brion, Jens Carsten Jantzen, and Raphaël Rouquier. During the last years, the subject...... of algebraic groups (in a broad sense) has seen important developments in several directions, also related to representation theory and algebraic geometry. The workshop aimed at presenting some of these developments in order to make them accessible to a "general audience" of algebraic group......-theorists, and to stimulate contacts between participants. Each of the first four days was dedicated to one area of research that has recently seen decisive progress: \\begin{itemize} \\item structure and classification of wonderful varieties, \\item finite reductive groups and character sheaves, \\item quantum cohomology...

  17. Group Grammar

    Science.gov (United States)

    Adams, Karen

    2015-01-01

    In this article Karen Adams demonstrates how to incorporate group grammar techniques into a classroom activity. In the activity, students practice using the target grammar to do something they naturally enjoy: learning about each other.

  18. MUYANG GROUP

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ With its headquarters in the historic city of Yangzhou,Jiangsu Muyang Group Co.,Ltd has since its founding in 1967 grown into a well-known group corporation whose activities cover research&development.project design,manufacturing,installation and services in a multitude of industries including feed machinery and engineering,storage engineering,grain machinery and engineering,environmental protection,conveying equipment and automatic control systems.

  19. Abelian groups

    CERN Document Server

    Fuchs, László

    2015-01-01

    Written by one of the subject’s foremost experts, this book focuses on the central developments and modern methods of the advanced theory of abelian groups, while remaining accessible, as an introduction and reference, to the non-specialist. It provides a coherent source for results scattered throughout the research literature with lots of new proofs. The presentation highlights major trends that have radically changed the modern character of the subject, in particular, the use of homological methods in the structure theory of various classes of abelian groups, and the use of advanced set-theoretical methods in the study of undecidability problems. The treatment of the latter trend includes Shelah’s seminal work on the undecidability in ZFC of Whitehead’s Problem; while the treatment of the former trend includes an extensive (but non-exhaustive) study of p-groups, torsion-free groups, mixed groups, and important classes of groups arising from ring theory. To prepare the reader to tackle these topics, th...

  20. Multi-criteria group decision making approach with variable weights in dynamic environment%动态环境下的群组专家多准则变权决策方法

    Institute of Scientific and Technical Information of China (English)

    孙永河; 段万春; 李春好; 许成磊

    2015-01-01

    Classic Multi-Criteria Decision Making(MCDM)method is unable to deal with the dynamicity in real world. Also, it is difficult to reflect the feedback action that Alternative Cluster(AC)dominates Criteria Cluster(CC). To over-come the above mentioned drawbacks, in this paper a multi-criteria group decision making approach with variable weights in a dynamic environment is suggested by synthesizing both data envelopment analysis and analytic network pro-cess. Compared with classic MCDM method, the outstanding advantages for the approach lie in following three points. A dynamic evolvement mechanism for MCDM model is proposed. A novel group information distilling way is given by ana-lyzing these statements that each alternative lies in criteria to express expert preference, which ensures no loss of every infor-mation. It may realize the decision with variable weights for alternatives, therefore, nonlinear interaction relation between AC and CC could be well reflected. The approach is validated to be feasible and scientific and can be well applied to solve the real world dynamic decision issues, such as selecting dynamic disaster relief alternatives, supplier dynamic eval-uation, etc.%为克服经典多准则决策(MCDM)方法不适应动态的决策环境、难以反映方案集对准则集的非线性反馈效应等方面缺陷,通过运用网络分析和数据包络分析技术,提出一种动态环境下的群组专家多准则变权决策方法。较之于经典MCDM方法,新方法主要创新之处在于:给出了MCDM模型的动态演化机理;通过专家对方案所处准则状态予以有偏好(无偏好)判断,提出一种保证信息无损的群组专家信息提取方式;实现了对方案的变权评价,有效反映出蕴含在系统内部的准则集与方案集的非线性交互作用关系。实例验证结果表明,所提方法是科学可行的,能够有效解决救灾方案动态优选、供应商动态评价等实践问题。

  1. Group Anonymity

    CERN Document Server

    Chertov, Oleg; 10.1007/978-3-642-14058-7_61

    2010-01-01

    In recent years the amount of digital data in the world has risen immensely. But, the more information exists, the greater is the possibility of its unwanted disclosure. Thus, the data privacy protection has become a pressing problem of the present time. The task of individual privacy-preserving is being thoroughly studied nowadays. At the same time, the problem of statistical disclosure control for collective (or group) data is still open. In this paper we propose an effective and relatively simple (wavelet-based) way to provide group anonymity in collective data. We also provide a real-life example to illustrate the method.

  2. 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...

  3. 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...

  4. Pre-Flare Dynamics of Sunspot Groups

    CERN Document Server

    Korsos, M B; Ludmany, A

    2014-01-01

    Several papers provide evidences that the most probable sites of flare onset are the regions of high horizontal magnetic field gradients in solar active regions. Besides the localization of flare producing areas the present work intends to reveal the characteristic temporal variations in these regions prior to flares. This study uses sunspot data instead of magnetograms, it follows the behaviour of a suitable defined proxy measure representing the horizontal magnetic field gradient. The source of the data is the SDD (SOHO/MDI-Debrecen Data) sunspot catalogue. The most promising pre-flare signatures are the following properties of the gradient variation: i) steep increase, ii) high maximum, iii) significant fluctuation and iv) a gradual decrease between the maximum and the flare onset which can be related to the "pull mode" of the current layer. These properties may yield a tool for the assessment of flare probability and intensity within the next 8-10 hours.

  5. Pre-flare dynamics of sunspot groups

    Energy Technology Data Exchange (ETDEWEB)

    Korsós, M. B.; Baranyi, T.; Ludmány, A., E-mail: korsos.marianna@csfk.mta.hu, E-mail: baranyi.tunde@csfk.mta.hu, E-mail: ludmany.andras@csfk.mta.hu [Heliophysical Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, 4010 Debrecen, P.O. Box 30 (Hungary)

    2014-07-10

    Several papers provide evidence that the most probable sites of flare onset are the regions of high horizontal magnetic field gradients in solar active regions. Besides the localization of flare-producing areas, this work intends to reveal the characteristic temporal variations in these regions prior to flares. This study uses sunspot data instead of magnetograms and follows the behavior of a suitable defined proxy measure representing the horizontal magnetic field gradient. The source of the data is the SDD (SOHO/MDI-Debrecen Data) sunspot catalog. The most promising pre-flare signatures are the following properties of gradient variation: (1) steep increase, (2) high maximum, (3) significant fluctuation, and (4) a gradual decrease between the maximum and the flare onset that can be related to the 'pull mode' of the current layer. These properties may yield a tool for the assessment of flare probability and intensity within the following 8-10 hr.

  6. Informal groups

    NARCIS (Netherlands)

    E. van den Berg; P. van Houwelingen; J. de Hart

    2011-01-01

    Original title: Informele groepen Going out running with a group of friends, rather than joining an official sports club. Individuals who decide to take action themselves rather than giving money to good causes. Maintaining contact with others not as a member of an association, but through an Inter

  7. COMMUNICATIONS GROUP

    CERN Multimedia

    L. Taylor

    2011-01-01

    The CMS Communications Group, established at the start of 2010, has been busy in all three areas of its responsibility: (1) Communications Infrastructure, (2) Information Systems, and (3) Outreach and Education. Communications Infrastructure There are now 55 CMS Centres worldwide that are well used by physicists working on remote CMS shifts, Computing operations, data quality monitoring, data analysis and outreach. The CMS Centre@CERN in Meyrin, is the centre of the CMS offline and computing operations, hosting dedicated analysis efforts such as during the CMS Heavy Ion lead-lead running. With a majority of CMS sub-detectors now operating in a “shifterless” mode, many monitoring operations are now routinely performed from there, rather than in the main Control Room at P5. The CMS Communications Group, CERN IT and the EVO team are providing excellent videoconferencing support for the rapidly-increasing number of CMS meetings. In parallel, CERN IT and ...

  8. Lego Group

    DEFF Research Database (Denmark)

    Møller Larsen, Marcus; Pedersen, Torben; Slepniov, Dmitrij

    2010-01-01

    The last years’ rather adventurous journey from 2004 to 2009 had taught the fifth-largest toy-maker in the world - the LEGO Group - the importance of managing the global supply chain effectively. In order to survive the largest internal financial crisis in its roughly 70 years of existence......, the management had, among many initiatives, decided to offshore and outsource a major chunk of its production to Flextronics. In this pursuit of rapid cost-cutting sourcing advantages, the LEGO Group planned to license out as much as 80 per cent of its production besides closing down major parts...... of the production in high cost countries. Confident with the prospects of the new partnership, the company signed a long-term contract with Flextronics. This decision eventually proved itself to have been too hasty, however. Merely three years after the contracts were signed, LEGO management announced that it would...

  9. Group Connections: Whole Group Teaching.

    Science.gov (United States)

    Griffiths, Dorothy

    2002-01-01

    A learner-centered approach to adult group instruction involved learners in investigating 20th-century events. The approach allowed learners to concentrate on different activities according to their abilities and gave them opportunities to develop basic skills and practice teamwork. (SK)

  10. Conformational Dynamics and Exchange Kinetics of N-Formyl and N-Acetyl Groups Substituting 3-Amino-3,6-dideoxy-α-d-galactopyranose, a Sugar Found in Bacterial O-Antigen Polysaccharides.

    Science.gov (United States)

    Engström, Olof; Mobarak, Hani; Ståhle, Jonas; Widmalm, Göran

    2017-10-04

    Three dimensional shape and conformation of carbohydrates are important factors in molecular recognition events and the N-acetyl group of a monosaccharide residue can function as a conformational gatekeeper whereby it influences the overall shape of the oligosaccharide. NMR spectroscopy and quantum mechanics (QM) calculations are used herein to investigate both the conformational preferences and the dynamic behavior of N-acetyl and N-formyl substituents of 3-amino-3,6-dideoxy-α-d-galactopyranose, a sugar and substitution pattern found in bacterial O-antigen polysaccharides. QM calculations suggest that the amide oxygen can be involved in hydrogen bonding with the axial OH4 group primarily but also with the equatorial OH2 group. However, an NMR J coupling analysis indicates that the θ1 torsion angle, adjacent to the sugar ring, prefers an ap conformation where conformations formyl-substituted compound (4)JHH coupling constants to the exo-cyclic group were detected and analyzed. A van't Hoff analysis revealed that the trans conformation at the amide bond is favored by ΔG° ≈ - 0.8 kcal·mol(-1) in the formyl-containing compound and with ΔG° ≈ - 2.5 kcal·mol(-1) when the N-acetyl group is the substituent. In both cases the enthalpic term dominates to the free energy, irrespective of water or DMSO as solvent, with only a small contribution from the entropic term. The cis-trans isomerization of the θ2 torsion angle, centered at the amide bond, was also investigated by employing (1)H NMR line shape analysis and (13)C NMR saturation transfer experiments. The extracted transition rate constants were utilized to calculate transition energy barriers that were found to be about 20 kcal·mol(-1) in both DMSO-d6 and D2O. Enthalpy had a higher contribution to the energy barriers in DMSO-d6 compared to in D2O, where entropy compensated for the loss of enthalpy.

  11. Group Development: Extending Tuckman's Theory.

    Science.gov (United States)

    Maples, Mary F.

    1988-01-01

    Presents a framework for extending the Tuckman model of developmental sequence in small groups. Considers Tuckman's stages of forming, storming, norming, performing, and adjourning lacking in descriptive depth and clear definition. Gathered and organized group dynamics graduate students' assessments of characteristics of stages over five-year…

  12. COMMUNICATIONS GROUP

    CERN Multimedia

    L. Taylor

    2011-01-01

    The CMS Communications Group has been busy in all three areas of its responsibility: (1) Communications Infrastructure, (2) Information Systems, and (3) Outreach and Education. Communications Infrastructure The 55 CMS Centres worldwide are well used by physicists working on remote CMS shifts, Computing operations, data quality monitoring, data analysis and outreach. The CMS Centre@CERN in Meyrin, is the centre of the CMS Offline and Computing operations, and a number of subdetector shifts can now take place there, rather than in the main Control Room at P5. A new CMS meeting room has been equipped for videoconferencing in building 42, next to building 40. Our building 28 meeting room and the facilities at P5 will be refurbished soon and plans are underway to steadily upgrade the ageing equipment in all 15 CMS meeting rooms at CERN. The CMS evaluation of the Vidyo tool indicates that it is not yet ready to be considered as a potential replacement for EVO. The Communications Group provides the CMS-TV (web) cha...

  13. COMMUNICATIONS GROUP

    CERN Multimedia

    L. Taylor

    2010-01-01

    The CMS Communications Group, established at the start of 2010, has been strengthening the activities in all three areas of its responsibility: (1) Communications Infrastructure, (2) Information Systems, and (3) Outreach and Education. Communications Infrastructure The Communications Group has invested a lot of effort to support the operations needs of CMS. Hence, the CMS Centres where physicists work on remote CMS shifts, Data Quality Monitoring, and Data Analysis are running very smoothly. There are now 55 CMS Centres worldwide, up from just 16 at the start of CMS data-taking. The latest to join are Imperial College London, the University of Iowa, and the Università di Napoli. The CMS Centre@CERN in Meyrin, which is now full repaired after the major flooding at the beginning of the year, has been at the centre of CMS offline and computing operations, most recently hosting a large fraction of the CMS Heavy Ion community during the lead-lead run. A number of sub-detector shifts can now take pla...

  14. Dynamics of Carroll particles

    NARCIS (Netherlands)

    Bergshoeff, Eric; Gomis, Joaquim; Longhi, Giorgio

    2014-01-01

    We investigate particles whose dynamics are invariant under the Carroll group. Although a single, free such Carroll particle has no non-trivial dynamics (the Carroll particle does not move), we show that non-trivial dynamics exists for a set of interacting Carroll particles. Furthermore, we gauge th

  15. COMMUNICATIONS GROUP

    CERN Multimedia

    L. Taylor

    2011-01-01

    Communications Infrastructure The 55 CMS Centres worldwide are well used by physicists working on remote CMS shifts, Computing operations, data quality monitoring, data analysis and outreach. The CMS Centre@CERN in Meyrin is particularly busy at the moment, hosting about 50 physicists taking part in the heavy-ion data-taking and analysis. Three new CMS meeting room will be equipped for videoconferencing in early 2012: 40/5B-08, 42/R-031, and 28/S-029. The CMS-TV service showing LHC Page 1, CMS Page 1, etc. (http://cmsdoc.cern.ch/cmscc/projector/index.jsp) is now also available for mobile devices: http://cern.ch/mcmstv. Figure 12: Screenshots of CMS-TV for mobile devices Information Systems CMS has a new web site: (http://cern.ch/cms) using a modern web Content Management System to ensure content and links are managed and updated easily and coherently. It covers all CMS sub-projects and groups, replacing the iCMS internal pages. It also incorporates the existing CMS public web site (http:/...

  16. COMMUNICATIONS GROUP

    CERN Multimedia

    L. Taylor

    2012-01-01

      Outreach and Education We are fortunate that our research has captured the public imagination, even though this inevitably puts us under the global media spotlight, as we saw with the Higgs seminar at CERN in December, which had 110,000 distinct webcast viewers. The media interest was huge with 71 media organisations registering to come to CERN to cover the Higgs seminar, which was followed by a press briefing with the DG and Spokespersons. This event resulted in about 2,000 generally positive stories in the global media. For this seminar, the CMS Communications Group prepared up-to-date news and public material, including links to the CMS results, animations and event displays [http://cern.ch/go/Ch8thttp://cern.ch/go/Ch8t]. There were 44,000 page-views on the CMS public website, with the Higgs news article being by far the most popular item. CMS event displays from iSpy are fast becoming the iconic media images, featuring on numerous major news outlets (BBC, CNN, MSN...) as well as in the sci...

  17. COMMUNICATIONS GROUP

    CERN Multimedia

    L. Taylor

    2010-01-01

    The recently established CMS Communications Group, led by Lucas Taylor, has been busy in all three of its main are areas of responsibility: Communications Infrastructure, Information Systems, and Outreach and Education Communications Infrastructure The damage caused by the flooding of the CMS Centre@CERN on 21st December has been completely repaired and all systems are back in operation. Major repairs were made to the roofs, ceilings and one third of the floor had to be completely replaced. Throughout these works, the CMS Centre was kept operating and even hosted a major press event for first 7 TeV collisions, as described below. Incremental work behind the scenes is steadily improving the quality of the CMS communications infrastructure, particularly Webcasting, video conferencing, and meeting rooms at CERN. CERN/IT is also deploying a pilot service of a new videoconference tool called Vidyo, to assess whether it might provide an enhanced service at a lower cost, compared to the EVO tool currently in w...

  18. Lefschetz Formulae for p-Adic Groups

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper, Lefschetz formulae for torus actions on p-adic groups are proven.These are similar to comparable formulae for real Lie groups. Applications lie in the realm of dynamical zeta functions.

  19. Multi-elemental characterization of tunnel and road dusts in Houston, Texas using dynamic reaction cell-quadrupole-inductively coupled plasma-mass spectrometry: Evidence for the release of platinum group and anthropogenic metals from motor vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Spada, Nicholas; Bozlaker, Ayse [Department of Civil and Environmental Engineering, University of Houston, Houston, TX 77204-4003 (United States); Chellam, Shankararaman, E-mail: chellam@uh.edu [Department of Civil and Environmental Engineering, University of Houston, Houston, TX 77204-4003 (United States); Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204-4004 (United States)

    2012-07-20

    Highlights: Black-Right-Pointing-Pointer Analytical method for PGEs, main group, transition and rare earth metals developed. Black-Right-Pointing-Pointer Comprehensive characterization of road and tunnel dust samples was accomplished. Black-Right-Pointing-Pointer PGEs in dusts arise from autocatalyst attrition. Black-Right-Pointing-Pointer Mobile sources also contributed to Cu, Zn, Ga, As, Mo, Cd, Sn, Sb, Ba, W and Pb. Black-Right-Pointing-Pointer All other elements, including rare earths arose from crustal sources. - Abstract: Platinum group elements (PGEs) including Rh, Pd, and Pt are important tracers for vehicular emissions, though their measurement is often challenging and difficult to replicate in environmental campaigns. These challenges arise from sample preparation steps required for PGE quantitation, which often cause severe isobaric interferences and spectral overlaps from polyatomic species of other anthropogenically emitted metals. Consequently, most previous road dust studies have either only quantified PGEs or included a small number of anthropogenic elements. Therefore a novel analytical method was developed to simultaneously measure PGEs, lanthanoids, transition and main group elements to comprehensively characterize the elemental composition of urban road and tunnel dusts. Dust samples collected from the vicinity of high-traffic roadways and a busy underwater tunnel restricted to single-axle (predominantly gasoline-driven) vehicles in Houston, TX were analyzed for 45 metals with the newly developed method using dynamic reaction cell-quadrupole-inductively coupled plasma-mass spectrometry (DRC-q-ICP-MS). Average Rh, Pd and Pt concentrations were 152 {+-} 52, 770 {+-} 208 and 529 {+-} 130 ng g{sup -1} respectively in tunnel dusts while they varied between 6 and 8 ng g{sup -1}, 10 and 88 ng g{sup -1} and 35 and 131 ng g{sup -1} in surface road dusts. Elemental ratios and enrichment factors demonstrated that PGEs in dusts originated from autocatalyst

  20. Group performance and decision making.

    Science.gov (United States)

    Kerr, Norbert L; Tindale, R Scott

    2004-01-01

    Theory and research on small group performance and decision making is reviewed. Recent trends in group performance research have found that process gains as well as losses are possible, and both are frequently explained by situational and procedural contexts that differentially affect motivation and resource coordination. Research has continued on classic topics (e.g., brainstorming, group goal setting, stress, and group performance) and relatively new areas (e.g., collective induction). Group decision making research has focused on preference combination for continuous response distributions and group information processing. New approaches (e.g., group-level signal detection) and traditional topics (e.g., groupthink) are discussed. New directions, such as nonlinear dynamic systems, evolutionary adaptation, and technological advances, should keep small group research vigorous well into the future.

  1. Gravitation Gauge Group

    CERN Document Server

    Ter-Kazarian, G T

    1997-01-01

    Suggested theory involves a drastic revision of a role of local internal symmetries in physical concept of curved geometry. Under the reflection of fields and their dynamics from Minkowski to Riemannian space a standard gauge principle of local internal symmetries is generalized. The gravitation gauge group is proposed, which is generated by hidden local internal symmetries. The developed mechanism enables one to infer Einstein's equation of gravitation, but only with strong difference from Einstein's theory at the vital point of well-defined energy-momentum tensor of gravitational field and conservation laws. The gravitational interaction as well as general distortion of manifold G(2.2.3) with hidden group U(1) was considered.

  2. Grouped frequent sequential patterns derived from terrestrial image time series to monitor landslide behaviour - Application to the dynamics of the Sanières/Roche Plombée rockslide.

    Science.gov (United States)

    Péricault, Youen; Pothier, Catherine; Méger, Nicolas; Trouvé, Emmanuel; Vernier, Flavien; Rigotti, Christophe; Malet, Jean-Philippe

    2016-04-01

    Image time series acquired with remote sensing methods based on optical terrestrial photogrammetry have great potential for understanding and monitoring the Earth surface dynamics at local scale, and are particularly interesting for landslide monitoring. Image correlation techniques can be applied to calculate the displacement fields, in either the image geometry or the terrain geometry if orthorectification procedures are applied. The resulting products are times series of displacement vectors for each epoch in which knowledge extraction techniques can be applied to discover relevant movement patterns in space and time. We used an unsupervised method (Grouped Frequent Sequential patterns / GFS-patterns) based on the mining of the displacement field. The method was originally developed for the analysis of time series of satellite images. It involves the extraction of trends / sub-trends affecting each pixel covering at least a minimum surface area and sufficiently connected to each other. The results of the mining are presented in spatio-temporal location maps (STL-map) of each GFS-pattern. In these maps, the spatial information is given by the pixel locations and the time information is displayed using a color ramp. The method is tested on a time series of 36 optical terrestrial images of the Sanières/Roche Plombée rockslide (South East French Alps) from 28 of July to 1 September 2014. From this series 35 2D displacement fields were calculated for epochs of three days, and the time series of vector magnitude and direction were analysed with GFS-patterns / STL-map. The method allowed identifying several patterns corresponding to different kinematical behaviour of the rockslide (long-term creep at the top of the slope, surficial movement of the debris at the base of the slope). The unsupervised knowledge extraction method GFS-pattern / STL-map, originally developed to analyse time series of satellite images showed in this study real possibilities of use for

  3. From mapping class groups to automorphism groups of free groups

    DEFF Research Database (Denmark)

    Wahl, Nathalie

    2005-01-01

    We show that the natural map from the mapping class groups of surfaces to the automorphism groups of free groups, induces an infinite loop map on the classifying spaces of the stable groups after plus construction. The proof uses automorphisms of free groups with boundaries which play the role...... of mapping class groups of surfaces with several boundary components....

  4. Visual Grouping by Neural Oscillators

    CERN Document Server

    Yu, Guoshen

    2008-01-01

    Distributed synchronization is known to occur at several scales in the brain, and has been suggested as playing a key functional role in perceptual grouping. State-of-the-art visual grouping algorithms, however, seem to give comparatively little attention to neural synchronization analogies. Based on the framework of concurrent synchronization of dynamic systems, simple networks of neural oscillators coupled with diffusive connections are proposed to solve visual grouping problems. Multi-layer algorithms and feedback mechanisms are also studied. The same algorithm is shown to achieve promising results on several classical visual grouping problems, including point clustering, contour integration and image segmentation.

  5. Discussion of the design of satellite-laser measurement stations in the eastern Mediterranean under the geological aspect. Contribution to the earthquake prediction research by the Wegener Group and to NASA's Crustal Dynamics Project

    Science.gov (United States)

    Paluska, A.; Pavoni, N.

    1983-01-01

    Research conducted for determining the location of stations for measuring crustal dynamics and predicting earthquakes is discussed. Procedural aspects, the extraregional kinematic tendencies, and regional tectonic deformation mechanisms are described.

  6. Groups, graphs and random walks

    CERN Document Server

    Salvatori, Maura; Sava-Huss, Ecaterina

    2017-01-01

    An accessible and panoramic account of the theory of random walks on groups and graphs, stressing the strong connections of the theory with other branches of mathematics, including geometric and combinatorial group theory, potential analysis, and theoretical computer science. This volume brings together original surveys and research-expository papers from renowned and leading experts, many of whom spoke at the workshop 'Groups, Graphs and Random Walks' celebrating the sixtieth birthday of Wolfgang Woess in Cortona, Italy. Topics include: growth and amenability of groups; Schrödinger operators and symbolic dynamics; ergodic theorems; Thompson's group F; Poisson boundaries; probability theory on buildings and groups of Lie type; structure trees for edge cuts in networks; and mathematical crystallography. In what is currently a fast-growing area of mathematics, this book provides an up-to-date and valuable reference for both researchers and graduate students, from which future research activities will undoubted...

  7. Marketing audit in group practice.

    Science.gov (United States)

    Blackburn, J M

    1984-01-01

    The marketing audit, whether large-scale or small-scale, will soon be critical to the success of every medical group practice. This dynamic process, in which the many components of a group's marketing efforts are analyzed, is examined from the perspective of ideal circumstances and unlimited resources, and more pragmatically, from the perspective of various-sized groups, with different resources and marketing talent. The audit components are prioritized, possible adaptations and combinations are presented, and reasonable implementation mechanisms, designed to address audit outcomes, are suggested.

  8. Transformations, Dynamics and Complexity

    CERN Document Server

    Glazunov, Nikolaj

    2011-01-01

    We review and investigate some new problems and results in the field of dynamical systems generated by iteration of maps, {\\beta}-transformations, partitions, group actions, bundle dynamical systems, Hasse-Kloosterman maps, and some aspects of complexity of the systems.

  9. Mutual Group Hypnosis: A Social Interaction Analysis.

    Science.gov (United States)

    Sanders, Shirley

    Mutual Group Hypnosis is discussed in terms of its similarity to group dynamics in general and in terms of its similarity to a social interaction program (Role Modeling) designed to foster the expression of warmth and acceptance among group members. Hypnosis also fosters a regression to prelogical thought processes in the service of the ego. Group…

  10. The symplectic group and classical mechanics.

    Science.gov (United States)

    Dragt, Alex J

    2005-06-01

    The symplectic group is the underlying symmetry group for Hamiltonian dynamics. Yet relatively little is commonly known about its properties including its Lie structure and representations. This paper describes and summarizes some of these properties; and, as a first application of symplectic group theory, provides a symplectic classification of all first-order differential equations in an even number of variables.

  11. Mutual Group Hypnosis: A Social Interaction Analysis.

    Science.gov (United States)

    Sanders, Shirley

    Mutual Group Hypnosis is discussed in terms of its similarity to group dynamics in general and in terms of its similarity to a social interaction program (Role Modeling) designed to foster the expression of warmth and acceptance among group members. Hypnosis also fosters a regression to prelogical thought processes in the service of the ego. Group…

  12. Integrated Groups and Smooth Distribution Groups

    Institute of Scientific and Technical Information of China (English)

    Pedro J. MIANA

    2007-01-01

    In this paper, we prove directly that α-times integrated groups define algebra homo-morphisms. We also give a theorem of equivalence between smooth distribution groups and α-times integrated groups.

  13. Which finite simple groups are unit groups?

    DEFF Research Database (Denmark)

    Davis, Christopher James; Occhipinti, Tommy

    2014-01-01

    We prove that if G is a finite simple group which is the unit group of a ring, then G is isomorphic to either (a) a cyclic group of order 2; (b) a cyclic group of prime order 2^k −1 for some k; or (c) a projective special linear group PSLn(F2) for some n ≥ 3. Moreover, these groups do all occur...

  14. Small group discussion: Students perspectives.

    Science.gov (United States)

    Annamalai, Nachal; Manivel, Rajajeyakumar; Palanisamy, Rajendran

    2015-08-01

    Various alternative methods are being used in many medical colleges to reinforce didactic lectures in physiology. Small group teaching can take on a variety of different tasks such as problem-solving, role play, discussions, brainstorming, and debate. Research has demonstrated that group discussion promotes greater synthesis and retention of materials. The aims of this study were to adopt a problem-solving approach by relating basic sciences with the clinical scenario through self-learning. To develop soft skills, to understand principles of group dynamics, and adopt a new teaching learning methodology. Experimental study design was conducted in Phase I 1(st) year medical students of 2014-2015 batch (n = 120). On the day of the session, the students were grouped into small groups (15 each). The session started with the facilitator starting off the discussion. Feedback forms from five students in each group was taken (n = 40). A five point Likert scale was used ranging from strongly agree to strongly disagree. Data were analyzed using IBM SPSS Statistics for Windows, Version 21.0. Armonk, NY: IBM Corp. Our results show that 70% of the students opined that small group discussion were interactive, friendly, innovative, built interaction between teacher and student. Small group discussion increased their thought process and helped them in better communication. The small group discussion was interactive, friendly, and bridged the gap between the teacher and student. The student's communication skills are also improved. In conclusion, small group discussion is more effective than the traditional teaching methods.

  15. Gravitation gauge group

    Energy Technology Data Exchange (ETDEWEB)

    Ter-Kazarian, G. T. [Byurakan Astrophysical Observatory (Armenia)

    1997-06-01

    The suggested theory involves a drastic revision of the role of local internal symmetries in the physical concept of curved geometry. Under the reflection of fields and their dynamics from Minkowski to Riemannian space a standard gauge principle of local internal symmetries has been generalized. A gravitation gauge group is proposed, which is generated by hidden local internal symmetries. In all circumstances, it seemed to be of the greatest importance for the understanding of the physical nature of gravity. The most promising aspect in their approach so far is the fact that the energy-momentum conservation laws of gravitational interacting fields are formulated quite naturally by exploiting all the advantages of auxiliary shadow fields on flat shadow space. The mechanism developed here enables one to infer Einstein`s equation of gravitation, but only with a strong difference from Einstein`s theory at the vital point of well-defined energy-momentum tensor of gravitational field and conservation laws. The gravitational interaction as well as the general distortion of the manifold G(2.2.3) with hidden group U{sup loc} (1) has been considered.

  16. The influence of trifluoromethyl groups on the miscibility of fluorinated alcohols with water : A molecular dynamics simulation study of 1,1,1-trifluoropropan-2-ol in aqueous solution

    NARCIS (Netherlands)

    Fioroni, M; Burger, K; Mark, AE; Roccatano, D

    2003-01-01

    1,1,1-Trifluoro-propan-2-ol (TFIP) alcohol has been used to study the influence of trifluoromethyl groups (CF3) on the physicochemical properties of fluorinated organic molecules. TFIP contains both a CF3 and a methyl (CH3) group. An atomistic study of TFIP thus can provide insight into the behavior

  17. Group Cohesion in Experiential Growth Groups

    Science.gov (United States)

    Steen, Sam; Vasserman-Stokes, Elaina; Vannatta, Rachel

    2014-01-01

    This article explores the effect of web-based journaling on changes in group cohesion within experiential growth groups. Master's students were divided into 2 groups. Both used a web-based platform to journal after each session; however, only 1 of the groups was able to read each other's journals. Quantitative data collected before and…

  18. Group decision-making: Factors that affect group effectiveness

    OpenAIRE

    Juliana Osmani

    2016-01-01

    Organizations are operating in a dynamic and turbulent environment. In these conditions, they have to make decisions for new problems or situations. Most of decisions are therefore non-programmed and unstructured, accompanied by risk and uncertainty. Moreover, the problems and situations are complex. All organizations are oriented towards group decisionmaking processes, as useful tools to cope with uncertainty and complexity. Apart from the necessity, companies are turning towards participato...

  19. Small-Group Instruction. Theory and Practice

    Science.gov (United States)

    1974-01-01

    Human Relations, vol. 1, 1948, cation Association, Washington, pp. 512-532. 1961, pp. 34-47, 125 Preceding Page Blank References 21. Cartwright , Dorwin ...Rela- Membership," in Dorwin Cartwright tions and Administration, Harvard and A. Zander (eds,), Group University Press, Cambridge, Mass., Dynamics... Dorwin Cartwright and A. 54. Johnson, D.M., and Smith, H.C. Zander (eds.) Group Dynamics: "Democratic Leadership in the Research and Theory, Row

  20. Group Work Publication-1991.

    Science.gov (United States)

    Zimpfer, David G.

    1992-01-01

    Lists 21 new publications in group work, of which 9 are reviewed. Those discussed include publications on group counseling and psychotherapy, structured groups, support groups, psychodrama, and social group work. (Author/NB)

  1. Estimating Causal Effects from Multilevel Group-Allocation Data

    Science.gov (United States)

    Gitelman, Alix I.

    2005-01-01

    In group-allocation studies for comparing behavioral, social, or educational interventions, subjects in the same group necessarily receive the same treatment, whereby a group and/or group-dynamic effect can confound the treatment effect. General counterfactual outcomes that depend on group characteristics, group membership, and treatment are…

  2. Group Evolution Discovery in Social Networks

    OpenAIRE

    Bródka, Piotr; Saganowski, Stanisław; Kazienko, Przemysław

    2013-01-01

    Group extraction and their evolution are among the topics which arouse the greatest interest in the domain of social network analysis. However, while the grouping methods in social networks are developed very dynamically, the methods of group evolution discovery and analysis are still uncharted territory on the social network analysis map. Therefore the new method for the group evolution discovery called GED is proposed in this paper. Additionally, the results of the first experiments on the ...

  3. Group theories: relevance to group safety studies.

    Science.gov (United States)

    Benevento, A L

    1998-01-01

    Promoting safety in the workplace has been attempted in a variety of ways. Increasingly, industries are using groups such as safety teams and quality circles to promote worker safety. Group influences on individual behavior and attitudes have long been studied in the social psychology literature, but the theories have not been commonly found outside the psychology arena. This paper describes the group theories of group polarization, risky shift, social loafing, groupthink and team think and attempts to apply these theories to existing studies that examine work group influences on safety. Interesting parallels were found but only one study examined group influences as their primary focus of research. Since groups are increasingly used for safety promotion, future research on safety that studies group influences with respect to current group theories is recommended.

  4. Dynamic Logics of Dynamical Systems

    CERN Document Server

    Platzer, André

    2012-01-01

    We survey dynamic logics for specifying and verifying properties of dynamical systems, including hybrid systems, distributed hybrid systems, and stochastic hybrid systems. A dynamic logic is a first-order modal logic with a pair of parametrized modal operators for each dynamical system to express necessary or possible properties of their transition behavior. Due to their full basis of first-order modal logic operators, dynamic logics can express a rich variety of system properties, including safety, controllability, reactivity, liveness, and quantified parametrized properties, even about relations between multiple dynamical systems. In this survey, we focus on some of the representatives of the family of differential dynamic logics, which share the ability to express properties of dynamical systems having continuous dynamics described by various forms of differential equations. We explain the dynamical system models, dynamic logics of dynamical systems, their semantics, their axiomatizations, and proof calcul...

  5. Magnetic translation groups as group extension

    OpenAIRE

    Florek, Wojciech

    1998-01-01

    Extensions of a direct product T of two cyclic groups Z_n1 and Z_n2 by an Abelian (gauge) group G with the trivial action of T on G are considered. All possible (nonequivalent) factor systems are determined using the Mac Lane method. Some of resulting groups describe magnetic translation groups. As examples extensions with G=U(1) and G=Z_n are considered and discussed.

  6. 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.

  7. AREVA group overview; Presentation du groupe AREVA

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-02-08

    This document presents the Group Areva, a world nuclear industry leader, from a financial holding company to an industrial group, operating in two businesses: the nuclear energy and the components. The structure and the market of the group are discussed, as the financial assets. (A.L.B.)

  8. Group decision-making: Factors that affect group effectiveness

    Directory of Open Access Journals (Sweden)

    Juliana Osmani

    2016-03-01

    Full Text Available Organizations are operating in a dynamic and turbulent environment. In these conditions, they have to make decisions for new problems or situations. Most of decisions are therefore non-programmed and unstructured, accompanied by risk and uncertainty. Moreover, the problems and situations are complex. All organizations are oriented towards group decisionmaking processes, as useful tools to cope with uncertainty and complexity. Apart from the necessity, companies are turning towards participatory processes also to benefit from the important advantages that these processes offer. Organizations have realized the importance of group decision-making processes to contribute to the creation of sustainable competitive advantages. Main objective of this paper is to show that group decision-making processes do not offer guarantee for good decisions, because the effectiveness of group is affected by many factors. So, the first thing done in this paper is discussing about the benefits and limitations that accompany the use of groups with decision-making purpose. Afterwards, we stop on the different factors that influence the group’s ability to make good decisions. The aim is to emphasize that regardless of the many advantages of groups, some factors as group size, type of communication within the group, leadership style, the norms, the differentiation of roles and statuses, cohesion and compliance degree should be the main elements to keep into consideration because they affect the effectiveness of group. In this regard, is discussed how such factors influence the quality of decision and then we try to draw some conclusions that can improve and make better and easier group decision-making processes.

  9. About group digital signatures

    National Research Council Canada - National Science Library

    Adriana Cristina Enache

    2012-01-01

    ...).A group digital signature is a digital signature with enhanced privacy features that allows members of a given group to anonymously sign messages on behalf of the group, producing a group signature...

  10. Influence of Group Size and Group Composition on the Adhered Distance Headway

    NARCIS (Netherlands)

    Duives, D.C.; Daamen, W.; Hoogendoorn, S.P.

    2014-01-01

    Research into the influence of groups on pedestrian flow dynamics has been limited. Previous research found that group size influences the walking velocity of pedestrians within the group and as such the capacity the pedestrian infrastructure. This paper's aim is to provide quantitative insights

  11. Introduction to Sporadic Groups

    Directory of Open Access Journals (Sweden)

    Luis J. Boya

    2011-01-01

    Full Text Available This is an introduction to finite simple groups, in particular sporadic groups, intended for physicists. After a short review of group theory, we enumerate the 1+1+16=18 families of finite simple groups, as an introduction to the sporadic groups. These are described next, in three levels of increasing complexity, plus the six isolated ''pariah'' groups. The (old five Mathieu groups make up the first, smallest order level. The seven groups related to the Leech lattice, including the three Conway groups, constitute the second level. The third and highest level contains the Monster group M, plus seven other related groups. Next a brief mention is made of the remaining six pariah groups, thus completing the 5+7+8+6=26 sporadic groups. The review ends up with a brief discussion of a few of physical applications of finite groups in physics, including a couple of recent examples which use sporadic groups.

  12. A virtual team group process.

    Science.gov (United States)

    Bell, Marnie; Robertson, Della; Weeks, Marlene; Yu, Deborah

    2002-01-01

    Virtual teams are a phenomenon of the Information Era and their existence in health care is anticipated to increase with technology enhancements such as telehealth and groupware. The mobilization and support of high performing virtual teams are important for leading knowledge-based health professionals in the 21st century. Using an adapted McGrath group development model, the four staged maturation process of a virtual team consisting of four masters students is explored in this paper. The team's development is analyzed addressing the interaction of technology with social and task dynamics. Throughout the project, leadership competencies of value to the group that emerged were demonstrated and incorporated into the development of a leadership competency assessment instrument. The demonstration of these competencies illustrated how they were valued and internalized by the group. In learning about the work of this virtual team, the reader will gain understanding of how leadership impacts virtual team performance.

  13. 一类抽象动力系统的C0群性质及其在迁移理论中的应用%The C0-group Properties of an Abstract Dynamic System and Application in Transport Theory

    Institute of Scientific and Technical Information of China (English)

    汪文珑; 许跟起

    2007-01-01

    In this paper we shall study properties of a class of abstract dynamic system.Using the decomposition method of Hilbert space, we give an explicit expression of spectrumof main operator and C0-group, then obtain the property of abstract dynamic system by the perturbation of bounded linear operator. As an application we investigate integro-differential equation arising in transport theory.%本文研究一类抽象动力系统的性质.使用Hilbert空间的分解方法,获得了主算子的谱和相应的群的表示;使用有界线性算子的扰动理论,获得了抽象动力算子的谱分解.作为应用,研究了迁移理论中的一类积-微分方程.

  14. Alliance and group cohesion in relationship education.

    Science.gov (United States)

    Owen, Jesse; Antle, Becky; Barbee, Anita

    2013-09-01

    Relationship education programs have been shown as an effective way to increase relationship functioning. There is less known about how process factors, such as alliance with the leader or group dynamics, affect outcomes in these interventions. We examined group cohesion and alliance with the leader in a relationship education program tailored for individuals. Specifically, we examined whether participants' ratings (n = 126) of the group cohesion and alliance with the leader were associated with changes in relationship adjustment, relationship confidence, and communication quality from pre- to postintervention. The results demonstrated that participants' perceptions of the cohesion among the members in their relationship education group, but not the leader-participant alliance, made a significant contribution to the changes in participants' relationship functioning. These results suggest that the group dynamics among the members in the group are important ingredients in relationship education. Implications for relationship programs are provided. © FPI, Inc.

  15. Group Work: How to Use Groups Effectively

    Science.gov (United States)

    Burke, Alison

    2011-01-01

    Many students cringe and groan when told that they will need to work in a group. However, group work has been found to be good for students and good for teachers. Employers want college graduates to have developed teamwork skills. Additionally, students who participate in collaborative learning get better grades, are more satisfied with their…

  16. Small Group Research

    Science.gov (United States)

    McGrath, Joseph E.

    1978-01-01

    Summarizes research on small group processes by giving a comprehensive account of the types of variables primarily studied in the laboratory. These include group structure, group composition, group size, and group relations. Considers effects of power, leadership, conformity to social norms, and role relationships. (Author/AV)

  17. Free Boolean Topological Groups

    Directory of Open Access Journals (Sweden)

    Ol’ga Sipacheva

    2015-11-01

    Full Text Available Known and new results on free Boolean topological groups are collected. An account of the properties that these groups share with free or free Abelian topological groups and properties specific to free Boolean groups is given. Special emphasis is placed on the application of set-theoretic methods to the study of Boolean topological groups.

  18. Radio properties of fossil galaxy groups

    Science.gov (United States)

    Miraghaei, H.; Khosroshahi, H. G.

    2016-09-01

    We study 1.4 GHz radio properties of a sample of fossil galaxy groups using GMRT radio observations and the FIRST survey catalog. Fossil galaxy groups, having no recent major mergers in their dominant galaxies and also group scale mergers, give us the opportunity to investigate the effect of galaxy merger on AGN activity. In this work, we compare the radio properties of a rich sample of fossil groups with a sample of normal galaxy groups and clusters and show that the brightest group galaxies in fossil groups are under luminous at 1.4 GHz, relative to the general population of the brightest group galaxies, indicating that the dynamically relaxed nature of fossil groups has influenced the AGN activity in their dominant galaxy.

  19. The effect of continuous grouping of pigs in large groups on stress response and haematological parameters

    DEFF Research Database (Denmark)

    Damgaard, Birthe Marie; Studnitz, Merete; Jensen, Karin Hjelholt

    2009-01-01

    from weaning at the age of 4 weeks to the age of 18 weeks after weaning. Limited differences were found in stress and haematological parameters between pigs in dynamic and static groups. The cortisol response to the stress test was increasing with the duration of the stress test in pigs from......The consequences of an ‘all in-all out' static group of uniform age vs. a continuously dynamic group with litter introduction and exit every third week were examined with respect to stress response and haematological parameters in large groups of 60 pigs. The experiment included a total of 480 pigs...

  20. RESEARCH DYNAMIC IN RELATION TO THE TEACHING AND TO THE EXTENSIONIST DIMENSIONS BY A GROUP OF UNIVERSITY STUDENTS / DINÁMICA INVESTIGATIVA EN LA RELACIÓN DIMENSIÓN DOCENTE Y EXTENSIONISTA POR UN GRUPO DE ESTUDIANTES UNIVERSITARIOS

    Directory of Open Access Journals (Sweden)

    Aida Rosa Gómez Labrada

    2011-04-01

    Full Text Available The higher education in Cuba locates in the center of attention the integral development of the professional to be, many actions have been made intended to get this purpose. One variant of this is the scientific investigation from the teaching-learning process and its relation with the extensionist process. This allows the development of knowledge and professional skills in a group of university students which eases the binding of theoretical and empirical aspects and towards a support of professional self-development. The strategy proposed is supported by the historical and cultural approach proposed by L. S. Vygotsky.

  1. MSUD Family Support Group

    Science.gov (United States)

    ... Group The MSUD Family Support Group is a non-profit 501 (c)(3) organization for those with MSUD ... Family Support Group is a 501(c)(3) non-profit organization with no paid staff. Funds are needed ...

  2. Profinite graphs and groups

    CERN Document Server

    Ribes, Luis

    2017-01-01

    This book offers a detailed introduction to graph theoretic methods in profinite groups and applications to abstract groups. It is the first to provide a comprehensive treatment of the subject. The author begins by carefully developing relevant notions in topology, profinite groups and homology, including free products of profinite groups, cohomological methods in profinite groups, and fixed points of automorphisms of free pro-p groups. The final part of the book is dedicated to applications of the profinite theory to abstract groups, with sections on finitely generated subgroups of free groups, separability conditions in free and amalgamated products, and algorithms in free groups and finite monoids. Profinite Graphs and Groups will appeal to students and researchers interested in profinite groups, geometric group theory, graphs and connections with the theory of formal languages. A complete reference on the subject, the book includes historical and bibliographical notes as well as a discussion of open quest...

  3. Homomorphisms of quantum groups

    CERN Document Server

    Meyer, Ralf; Woronowicz, Stanisław Lech

    2010-01-01

    We introduce some equivalent notions of homomorphisms between quantum groups that behave well with respect to duality of quantum groups. Our equivalent definitions are based on bicharacters, coactions, and universal quantum groups, respectively.

  4. Food Groups Recipes

    OpenAIRE

    2012-01-01

    15 pages In 2011, My Plate replaced the Food Pyramid as a visual representation for the USDA Dietary Guidelines. This publication, a group of recipes based on this new division of food groups, reflects the effort of the USDA and other groups to translate science-based research into everyday practice for Americans. Fifteen recipes (3 from each food group) show ways to use foods from each food group. They are complete with basic nutritional analyses and food group amounts.

  5. Locally minimal topological groups

    OpenAIRE

    Außenhofer, Lydia; Chasco, María Jesús; Dikranjan, Dikran; Domínguez, Xabier

    2009-01-01

    A Hausdorff topological group $(G,\\tau)$ is called locally minimal if there exists a neighborhood $U$ of 0 in $\\tau$ such that $U$ fails to be a neighborhood of zero in any Hausdorff group topology on $G$ which is strictly coarser than $\\tau.$ Examples of locally minimal groups are all subgroups of Banach-Lie groups, all locally compact groups and all minimal groups. Motivated by the fact that locally compact NSS groups are Lie groups, we study the connection between local minimality and the ...

  6. GROUP PROFILE Computer Technique

    Directory of Open Access Journals (Sweden)

    Andrey V. Sidorenkov

    2015-01-01

    Full Text Available This article contains a description of the structure, the software and functional capabilities, and the scope and purposes of application of the Group Profile (GP computer technique. This technique rests on a conceptual basis (the microgroup theory, includes 16 new and modified questionnaires, and a unique algorithm, tied to the questionnaires, for identification of informal groups. The GP yields a wide range of data about the group as a whole (47 indices, each informal group (43 indices, and each group member (16 indices. The GP technique can be used to study different types of groups: production (work groups, design teams, military units, etc., academic (school classes, student groups, and sports.

  7. Managing parental groups: personal impact of a group leadership course for child healthcare nurses.

    Science.gov (United States)

    Lefèvre, Åsa; Lundqvist, Pia; Drevenhorn, Eva; Hallström, Inger

    2017-02-01

    To investigate the experience and personal impact of a group leadership course for child healthcare nurses. During their child's first year, all parents in Sweden are invited to participate in parental groups within the child health service; however, only 49% choose to participate. Despite extensive experience, child healthcare nurses find managing parental groups challenging and express a need for training in group dynamics and group leadership. The study was designed as a controlled study with a pretest/post-test design where the participants form their own control group. A group leadership course was given to 56 child healthcare nurses and evaluated in a pre- and postintervention questionnaire, a course evaluation and an interview with the course leaders. The child healthcare nurses felt their group leadership skills were strengthened and the majority (96%) felt that the course had changed their way of leading parental groups. They felt that the group leader role had been clarified and that they had obtained several new tools to use in their groups. Clarifying the role of group leader and adding knowledge about group leadership and dynamics seems to have increased the self-confidence for child healthcare nurses in group leadership. Improved confidence in group management might motivate the child healthcare nurses to further develop parental groups to attract the parents who currently choose not to participate. © 2016 John Wiley & Sons Ltd.

  8. Dynamical Languages

    Science.gov (United States)

    Xie, Huimin

    The following sections are included: * Definition of Dynamical Languages * Distinct Excluded Blocks * Definition and Properties * L and L″ in Chomsky Hierarchy * A Natural Equivalence Relation * Symbolic Flows * Symbolic Flows and Dynamical Languages * Subshifts of Finite Type * Sofic Systems * Graphs and Dynamical Languages * Graphs and Shannon-Graphs * Transitive Languages * Topological Entropy

  9. Ordered groups and infinite permutation groups

    CERN Document Server

    1996-01-01

    The subjects of ordered groups and of infinite permutation groups have long en­ joyed a symbiotic relationship. Although the two subjects come from very different sources, they have in certain ways come together, and each has derived considerable benefit from the other. My own personal contact with this interaction began in 1961. I had done Ph. D. work on sequence convergence in totally ordered groups under the direction of Paul Conrad. In the process, I had encountered "pseudo-convergent" sequences in an ordered group G, which are like Cauchy sequences, except that the differences be­ tween terms of large index approach not 0 but a convex subgroup G of G. If G is normal, then such sequences are conveniently described as Cauchy sequences in the quotient ordered group GIG. If G is not normal, of course GIG has no group structure, though it is still a totally ordered set. The best that can be said is that the elements of G permute GIG in an order-preserving fashion. In independent investigations around that t...

  10. O método funcional na prática da enfermagem abordado através da dinâmica de grupo: relato de uma experiência The functional method in nursing practice that was about the group dynamic: of an experience

    Directory of Open Access Journals (Sweden)

    Carla Aparecida Spagnol

    2001-06-01

    Full Text Available Este estudo discute o método funcional na enfermagem, abordado através de uma dinâmica de grupo desenvolvida com mestrandos da EERP-USP, sendo divididos em três grupos. Após a dinâmica, responderam um questionário com 04 perguntas. As respostas do grupo I mostraram desvantagens da modalidade funcional que interferem no trabalho como: relações impessoais, fragmentação de tarefas e centralização das decisões, gerando insatisfação no trabalhador. Os grupos II e III apontaram algumas vantagens quando o trabalho é baseado em equipe, das quais destacamos a troca de experiências, o planejamento participativo e as decisões compartilhadas, sendo estes, fatores que levam à satisfação no trabalho.This study discusses the functional method applied to Nursing, approached through a group dynamics developed with three groups of Master students from the University of Seto Paulo at Ribeirão Preto College of Nursing. After the dynamics, the subjects answered a questionnaire with four questions. The responses of the first group showed the limitations of the functional model that interfere in the work such as: impersonal relationships, fragmentation of tasks, centralization of decisions causing the workers' dissatisfaction. The groups II and III pointed out some advantages when the work is based on a team, such as the exchange of experiences, participant planning and shared decisions, resulting in satisfaction at work.

  11. Therapists' group attachments and their expectations of patients' attitudes about group therapy.

    Science.gov (United States)

    Marmarosh, Cheri L; Franz, Victoria A; Koloi, Mosetsanagape; Majors, Rebekah C; Rahimi, Amanda M; Ronquillo, Jonne G; Somberg, Rachel J; Swope, Jessica S; Zimmer, Katherine

    2006-07-01

    A large body of literature has supported the application of attachment theory to the understanding of psychotherapy. In addition, a more recent social psychological literature is exploring the application of attachment theory to the area of group dynamics and group process. The current study is designed to integrate these two distinct bodies of literature. In a preliminary fashion, we examined the relationship between group therapists' group attachment styles and their assumptions and expectations of their patients' attitudes about group psychotherapy. Seventy-six therapists completed the Smith, Murphy & Coats (1999) measure of group attachment style. They also completed the Revised Group Therapy Survey (Carter, Mitchell, & Krautheim, 2001) from the viewpoint of a typical patient they treat. As hypothesized, therapists with more group attachment anxiety assumed that patients would hold more negative myths and misconceptions about group treatment than therapists with less group attachment anxiety. The utility of a group attachment construct in future research and practice is discussed.

  12. Communication in Organizational Groups

    OpenAIRE

    Monica RADU

    2007-01-01

    Organizational group can be defined as some persons between who exist interactive connections (functional, communication, affective, normative type). Classification of these groups can reflect the dimension, type of relationship or type of rules included. Organizational groups and their influence over the individual efficiency and the efficiency of the entire group are interconnected. Spontaneous roles in these groups sustain the structure of the relationship, and the personality of each indi...

  13. Neutralization of a sec-ammonium group unusually stabilized by the "rotaxane effect": synthesis, structure, and dynamic nature of a "free" sec-amine/crown ether-type rotaxane.

    Science.gov (United States)

    Nakazono, Kazuko; Takata, Toshikazu

    2010-12-10

    A fifteen-year riddle has been settled: neutralization, the most popular chemical event, of a crown ether/sec-ammonium salt-type rotaxane has been achieved and a completely nonionic crown ether/sec-amine-type rotaxane isolated. A [2]rotaxane was prepared as a typical substrate from a mixture of dibenzo[24]crown-8 ether (DB24C8) and sec-ammonium hexafluorophosphate (PF(6)) with a terminal hydroxy group through end-capping with 3,5-dimethylbenzoic anhydride in the presence of tributylphosphane as a catalyst in 90% yield. A couple of approaches to the neutralization of the ammonium rotaxane were investigated to isolate the free sec-amine-type rotaxane by decreasing the degree of thermodynamic and kinetic stabilities. One approach was the counteranion-exchange method in which the soft counterion PF(6)(-) was replaced with the fluoride anion by mixing with tetrabutylammonium fluoride, thus decreasing the cationic character of the ammonium moiety. Subsequent simple washing with a base allowed us to isolate the free sec-amine-type rotaxane in a quantitative yield. The other approach was a synthesis based on a protection/deprotection protocol. The acylation of the sec-ammonium moiety with 2,2,2-trichloroethyl chloroformate gave an N-carbamated rotaxane that could be deprotected by treating with zinc in acetic acid to afford the corresponding free sec-amine-type rotaxane in a quantitative yield. The structure of the free sec-amine-type rotaxane was fully confirmed by spectral and analytical data. The generality of the counteranion-exchange method was also confirmed through the neutralization of a bisammonium-type [3]rotaxane. The mechanism was studied from the proposed potential-energy diagram of the rotaxanes with special emphasis on the role of the PF(6)(-) counterion.

  14. Cortical dynamics of figure-ground separation in response to 2D pictures and 3D scenes:How V2 combines border ownership, stereoscopic cues, and Gestalt grouping rules

    Directory of Open Access Journals (Sweden)

    Stephen eGrossberg

    2016-01-01

    Full Text Available The FACADE model, and its laminar cortical realization and extension in the 3D LAMINART model, have explained, simulated, and predicted many perceptual and neurobiological data about how the visual cortex carries out 3D vision and figure-ground perception, and how these cortical mechanisms enable 2D pictures to generate 3D percepts of occluding and occluded objects. In particular, these models have proposed how border ownership occurs, but have not yet explicitly explained the correlation between multiple properties of border ownership neurons in cortical area V2 that were reported in a remarkable series of neurophysiological experiments by von der Heydt and his colleagues; namely, border ownership, contrast preference, binocular stereoscopic information, selectivity for side-of-figure, Gestalt rules, and strength of attentional modulation, as well as the time course during which such properties arise. This article shows how, by combining 3D LAMINART properties that were discovered in two parallel streams of research, a unified explanation of these properties emerges. This explanation proposes, moreover, how these properties contribute to the generation of consciously seen 3D surfaces. The first research stream models how processes like 3D boundary grouping and surface filling-in interact in multiple stages within and between the V1 interblob – V2 interstripe – V4 cortical stream and the V1 blob – V2 thin stripe – V4 cortical stream, respectively. Of particular importance for understanding figure-ground separation is how these cortical interactions convert computationally complementary boundary and surface mechanisms into a consistent conscious percept, including the critical use of surface contour feedback signals from surface representations in V2 thin stripes to boundary representations in V2 interstripes. Remarkably, key figure-ground properties emerge from these feedback interactions. The second research stream shows how cells that

  15. Dynamic features of the selective pressure on the human immunodeficiency virus type 1 (HIV-1 gp120 CD4-binding site in a group of long term non progressor (LTNP subjects

    Directory of Open Access Journals (Sweden)

    Mazzi Benedetta

    2009-01-01

    Full Text Available Abstract The characteristics of intra-host human immunodeficiency virus type 1 (HIV-1 env evolution were evaluated in untreated HIV-1-infected subjects with different patterns of disease progression, including 2 normal progressor [NP], and 5 Long term non-progressor [LTNP] patients. High-resolution phylogenetic analysis of the C2-C5 env gene sequences of the replicating HIV-1 was performed in sequential samples collected over a 3–5 year period; overall, 301 HIV-1 genomic RNA sequences were amplified from plasma samples, cloned, sequenced and analyzed. Firstly, the evolutionary rate was calculated separately in the 3 codon positions. In all LTNPs, the 3rd codon mutation rate was equal or even lower than that observed at the 1st and 2nd positions (p = 0.016, thus suggesting strong ongoing positive selection. A Bayesian approach and a maximum-likelihood (ML method were used to estimate the rate of virus evolution within each subject and to detect positively selected sites respectively. A great number of N-linked glycosylation sites under positive selection were identified in both NP and LTNP subjects. Viral sequences from 4 of the 5 LTNPs showed extensive positive selective pressure on the CD4-binding site (CD4bs. In addition, localized pressure in the area of the IgG-b12 epitope, a broad neutralizing human monoclonal antibody targeting the CD4bs, was documented in one LTNP subject, using a graphic colour grade 3-dimensional visualization. Overall, the data shown here documenting high selective pressure on the HIV-1 CD4bs of a group of LTNP subjects offers important insights for planning novel strategies for the immune control of HIV-1 infection.

  16. Customized Assessment Group Initiative: A Complementary Approach to Students' Learning

    Science.gov (United States)

    Akindayomi, Akinloye

    2015-01-01

    This study, conducted in a US setting, examines the importance of group dynamics that emphasize cooperative team building through the proposed grouping strategy called Customized Assessment Group Initiative (CAGI). CAGI is a student grouping strategy designed to operationalize the mutual accountability concept central to the definition of teams by…

  17. Global Dynamics for Symmetric Planar Maps

    CERN Document Server

    Alarcon, B; Labouriau, I S

    2012-01-01

    We consider sufficient conditions to determine the global dynamics for equivariant maps of the plane with a unique fixed point which is also hyperbolic. When the map is equivariant under the action of a compact Lie group, it is possible to describe the local dynamics and - from this - also the global dynamics. In particular, if the group contains a reflection, there is a line invariant by the map. This allows us to use results based on the theory of free homeomorphisms to describe the global dynamical behaviour. In the absence of reflections, we use equivariant examples to show that global dynamics may not follow from local dynamics near the unique fixed point.

  18. Locally minimal topological groups

    CERN Document Server

    enhofer, Lydia Au\\ss; Dikranjan, Dikran; Domínguez, Xabier

    2009-01-01

    A Hausdorff topological group $(G,\\tau)$ is called locally minimal if there exists a neighborhood $U$ of 0 in $\\tau$ such that $U$ fails to be a neighborhood of zero in any Hausdorff group topology on $G$ which is strictly coarser than $\\tau.$ Examples of locally minimal groups are all subgroups of Banach-Lie groups, all locally compact groups and all minimal groups. Motivated by the fact that locally compact NSS groups are Lie groups, we study the connection between local minimality and the NSS property, establishing that under certain conditions, locally minimal NSS groups are metrizable. A symmetric subset of an abelian group containing zero is said to be a GTG set if it generates a group topology in an analogous way as convex and symmetric subsets are unit balls for pseudonorms on a vector space. We consider topological groups which have a neighborhood basis at zero consisting of GTG sets. Examples of these locally GTG groups are: locally pseudo--convex spaces, groups uniformly free from small subgroups (...

  19. Free products in R. Thompson's group V

    CERN Document Server

    Bleak, Collin

    2009-01-01

    We investigate free product structures in R. Thompson's group V, primarily by studying the topological dynamics associated with V's action on the Cantor Set. We show that the class of free products which can be embedded into V includes the free product of any two finite groups, the free product of any finite group with Q/Z, and the countable non-abelian free groups. We also show the somewhat surprising result that Z^2*Z does not embed in V, even though V has many embedded copies of Z^2 and has many embedded copies of free products of pairs of its subgroups.

  20. Higher arithmetic Chow groups

    CERN Document Server

    Gil, J I Burgos

    2009-01-01

    We give a new construction of higher arithmetic Chow groups for quasi-projective arithmetic varieties over a field. Our definition agrees with the higher arithmetic Chow groups defined by Goncharov for projective arithmetic varieties over a field. These groups are the analogue, in the Arakelov context, of the higher algebraic Chow groups defined by Bloch. The degree zero group agrees with the arithmetic Chow groups of Burgos. Our new construction is shown to be a contravariant functor and is endowed with a product structure, which is commutative and associative.