Random matrix analysis of the QCD sign problem for general topology

Motivated by the important role played by the phase of the fermion determinant in the investigation of the sign problem in lattice QCD at nonzero baryon density, we derive an analytical formula for the average phase factor of the fermion determinant for general topology in the microscopic limit of chiral random matrix theory at nonzero chemical potential, for both the quenched and the unquenched case. The formula is a nontrivial extension of the expression for zero topology derived earlier by Splittorff and Verbaarschot. Our analytical predictions are verified by detailed numerical random matrix simulations of the quenched theory.Comment: 33 pages, 9 figures; v2: minor corrections, references added, figures with increased statistics, as published in JHE

Resonant nucleation of spatio-temporal order via parametric modal amplification

We investigate, analytically and numerically, the emergence of spatio-temporal order in nonequilibrium scalar field theories. The onset of order is triggered by destabilizing interactions (DIs), which instantaneously change the interacting potential from a single to a double-well, tunable to be either degenerate (SDW) or nondegenerate (ADW). For the SDW case, we observe the emergence of spatio-temporal coherent structures known as oscillons. We show that this emergence is initially synchronized, the result of parametric amplification of the relevant oscillon modes. We also discuss how these ordered structures act as bottlenecks for equipartition. For ADW potentials, we show how the same parametric amplification mechanism may trigger the rapid decay of a metastable state. For a range of temperatures, the decay rates associated with this resonant nucleation can be orders of magnitude larger than those computed by homogeneous nucleation, with time-scales given by a simple power law, $\tau_{\rm RN}\sim[E_b/k_BT]^B$, where $B$ depends weakly on the temperature and $E_b/k_BT$ is the free-energy barrier of a critical fluctuation.Comment: 38 pages, 20 figures now included within the tex

Plaats delict-onderzoek met vooruitziende blik: Anticiperen op alternatieve scenario’s tijdens het sporenonderzoek op de plaats delict

Criminal Justice: Legitimacy, accountability, and effectivit

Application of the Maximum Entropy Method to the (2+1)d Four-Fermion Model

We investigate spectral functions extracted using the Maximum Entropy Method from correlators measured in lattice simulations of the (2+1)-dimensional four-fermion model. This model is particularly interesting because it has both a chirally broken phase with a rich spectrum of mesonic bound states and a symmetric phase where there are only resonances. In the broken phase we study the elementary fermion, pion, sigma and massive pseudoscalar meson; our results confirm the Goldstone nature of the pi and permit an estimate of the meson binding energy. We have, however, seen no signal of sigma -> pi pi decay as the chiral limit is approached. In the symmetric phase we observe a resonance of non-zero width in qualitative agreement with analytic expectations; in addition the ultra-violet behaviour of the spectral functions is consistent with the large non-perturbative anomalous dimension for fermion composite operators expected in this model.Comment: 25 pages, 13 figure

Maintenance and refurbishment planning for a group of bridges

During the service, highway overpasses are exposed to various deterioration processes. The rate of these unavoidable processes depends on intensity of usage, weather influences and maintenance level. If maintenance works are not planned and executed in an adequate manner, the performance of the structures under consideration reduces. Planning an optimum set of intervention measures on the level of a group of structures is a complex task that is often left to subjective, partial decisions of managers that have to take int the account also financial limitations.\ud A group of 27 highway overpasses, spanning over the highway section under consideration, was analysed. A multi-criteria model for the selection of bridges that should have priority in the refurbishment process was developed. Condition rating data were collected from the periodic check\ud reports and and structured appropriately. Key criteria that need to be taken into the account were identified: condition ration of the whole structure, age of the pass, possibility of joining the works on a string of passes, indirect cost influence, refurbishment cost for a structure and deterioraton rate of the structure. Relative importance among these citeria was determined by using Analytical Hierarchy Method (AHP). On this basis, a multi-criteria model to be used for the selection of a set of structures\ud that have refurbishment priority in the case of limited financial contribution was developed. Refurbishment priority was identified for a group of structures that have, as a whole, a maximum overall benefit with respect to the selected criteria and their relative importance. Further, the analysis of the influence of the financial constraint magnitude upon the selection of structures to be repaired and the accompanying benefits ( that can facilitate the decision of the decision-makers' side) was carried out. The obtained results show that the proposed model can serve as an efficient tool used in rational selection of group of structures yielding the maximum overall benefit, and in analysis of possibilitie that lead to additional benefit with minimum financial input

Groepsfunctioneren in de kinderopvang, een conceptueel kader

Contains fulltext : 90425.pdf (publisher's version ) (Open Access)In Dutch child care it is generally assumed that group functioning influences children's wellbeing and development. Yet, a clear definition of the functioning of a child care group is lacking. This article describes a conceptual framework for child care group functioning based on Robert Hinde's model of social complexity (1987). Group functioning is defined as a relatively stable pattern of interactions between group members, associated with cognitions (expectations) and emotions, that develops over time as a function of internal (group) and external (contextual) influences. Each group has its own unique pattern, which may be described on two dimensions, namely group cohesion and emotional climate. Cohesion is the extent to which interactions within a group reflect togetherness and connectedness. It concerns the number and pattern of dyadic interactions (network structure), the extent to which the behaviour of individual group members is mutually coordinated (joint action) and the degree of positive involvement between group members. The emotional climate concerns the positive versus negative tone of the emotions expressed in the group. Although little is known about group functioning in the child care setting, it is plausible that it influences children's socio-emotional and cognitive development. Therefore group functioning can be seen as a relevant part of child care quality. Additional empirical research is needed to acquire more knowledge about group functioning in child care.18 p

Group functioning in child care centers: Conceptualization, measurement, and relation with structural characteristics

Item does not contain fulltextThis article introduces and conceptually underpins an instrument to measure group functioning in child care groups, the Group Functioning Instrument for Child Care (GFI-CC). This instrument was applied in 44 Dutch child care groups (0- to 4-year-olds). The results of this first explorative investigation with the GFI-CC provided initial support for an underlying conceptual model of group functioning in child care centers based on cohesion (network structure, action coordination, and involvement) and emotional climate. The relation between group functioning and structural group characteristics was also examined. Mean age and group continuity (i.e., how long the children have already been attending the group) predicted group functioning, with higher group functioning in groups with older children and in groups with greater continuity. Group size and group constancy (i.e., how many days a week children attend the child care group together) did not independently contribute to the prediction of the group functioning variables.27 p

Can you be persuaded? Individual differences in susceptibililty to persuasion

Persuasive technologies are growing in popularity and many designers create systems which intentionally change users attitudes or behaviors. This study shows that peoples individual differences in susceptibility to persuasion, as implemented using the six persuasion principles proposed by Cialdini 2, relates to their compliance to a persuasive request which is accompanied by a persuasive cue. This result is a starting point for designers to start incorporating individual differences in susceptibility to persuasive cues in their adaptive persuasive systems