Trigger strategies for SUSY searches at the LHC

Supersymmetry will be searched for in a variety of final states at the LHC. It is crucial that a robust, efficient and unbiased trigger selection for SUSY is implemented from the very early days of data taking. After a brief description of the ATLAS and the CMS trigger systems, and a more in-depth discussion of the ATLAS High-Level Trigger, a triggering strategy is outlined for early SUSY searches at the LHC.Comment: Submitted for the SUSY07 Proceedings, 4 pages, 3 eps figures, LaTe

Synchronization between variable time delayed systems and cryptography

In this letter we consider a prototype model which is described as an autonomous continuous time delayed differential equation with just one variable. The chaos has been investigated with variable delay time and the synchronization phenomenon is examined both numerically and analytically using the Krasovskii-Lyapunov functions. We have applied adaptive coupling law for synchronization,where the coupling equation also contains delay with modulated time. We also studied the effect of cryptography for this coupled system and the message extraction procedure is illustrated with the help of simulated results.Comment: 9 pages,3 figures. Submitted to EP

On the Consensus Threshold for the Opinion Dynamics of Krause-Hegselmann

In the consensus model of Krause-Hegselmann, opinions are real numbers between 0 and 1 and two agents are compatible if the difference of their opinions is smaller than the confidence bound parameter \epsilon. A randomly chosen agent takes the average of the opinions of all neighbouring agents which are compatible with it. We propose a conjecture, based on numerical evidence, on the value of the consensus threshold \epsilon_c of this model. We claim that \epsilon_c can take only two possible values, depending on the behaviour of the average degree d of the graph representing the social relationships, when the population N goes to infinity: if d diverges when N goes to infinity, \epsilon_c equals the consensus threshold \epsilon_i ~ 0.2 on the complete graph; if instead d stays finite when N goes to infinity, \epsilon_c=1/2 as for the model of Deffuant et al.Comment: 15 pages, 7 figures, to appear in International Journal of Modern Physics C 16, issue 2 (2005

The Sznajd Consensus Model with Continuous Opinions

In the consensus model of Sznajd, opinions are integers and a randomly chosen pair of neighbouring agents with the same opinion forces all their neighbours to share that opinion. We propose a simple extension of the model to continuous opinions, based on the criterion of bounded confidence which is at the basis of other popular consensus models. Here the opinion s is a real number between 0 and 1, and a parameter \epsilon is introduced such that two agents are compatible if their opinions differ from each other by less than \epsilon. If two neighbouring agents are compatible, they take the mean s_m of their opinions and try to impose this value to their neighbours. We find that if all neighbours take the average opinion s_m the system reaches complete consensus for any value of the confidence bound \epsilon. We propose as well a weaker prescription for the dynamics and discuss the corresponding results.Comment: 11 pages, 4 figures. To appear in International Journal of Modern Physics

Do extremists impose the structure of social networks?

The structure and the properties of complex networks essentially depend on the way how nodes get connected to each other. We assume here that each node has a feature which attracts the others. We model the situation by assigning two numbers to each node, \omega and \alpha, where \omega indicates some property of the node and \alpha the affinity towards that property. A node A is more likely to establish a connection with a node B if B has a high value of \omega and A has a high value of \alpha. Simple computer simulations show that networks built according to this principle have a degree distribution with a power law tail, whose exponent is determined only by the nodes with the largest value of the affinity \alpha (the "extremists"). This means that the extremists lead the formation process of the network and manage to shape the final topology of the system. The latter phenomenon may have implications in the study of social networks and in epidemiology.Comment: 4 pages, 3 figure

The Krause-Hegselmann Consensus Model with Discrete Opinions

The consensus model of Krause and Hegselmann can be naturally extended to the case in which opinions are integer instead of real numbers. Our algorithm is much faster than the original version and thus more suitable for applications. For the case of a society in which everybody can talk to everybody else, we find that the chance to reach consensus is much higher as compared to other models; if the number of possible opinions Q<=7, in fact, consensus is always reached, which might explain the stability of political coalitions with more than three or four parties. For Q>7 the number S of surviving opinions is approximately the same independently of the size N of the population, as long as Q<N. We considered as well the more realistic case of a society structured like a Barabasi-Albert network; here the consensus threshold depends on the outdegree of the nodes and we find a simple scaling law for S, as observed for the discretized Deffuant model.Comment: 12 pages, 6 figure

Transformation of Rural Teachers Earning Graduate Degrees

This study tells the stories of four successful graduate students within a cohort of learners who were earning graduate degrees in technology for education and training by distance. The students were practicing teachers in the Dakota Interactive Academic Link (DIAL) consortium. Courses were offered by the University of South Dakota, using videoconferencing through the statewide Digital Distance Network (DDN) and WebCT asynchronous discussions. Mezirows 1991 theory of transformative learning suggests that adult learners may experience a transformational experience. Results showed that the four study participants experienced major changes in their way of thinking about learning and themselves. Conducting longitudinal studies in which adults are interviewed throughout their graduate school experience is recommended