A Computational Model of Worker Protest

This paper presents an agent-based model of worker protest. Workers have varying degrees of grievance depending on the difference between their wage and the average of their neighbors. They protest with probabilities proportional to grievance, but are inhibited by the risk of being arrested – which is determined by the ratio of coercive agents to probable rebels in the local area. We explore the effect of similarity perception on the dynamics of collective behavior. If workers are surrounded by more in-group members, they are more risk-taking; if surrounded by more out-group members, more risk-averse. Individual interest and group membership jointly affect patterns of workers protest: rhythm, frequency, strength, and duration of protest outbreaks. Results indicate that when wages are more unequally distributed, the previous outburst tends to suppress the next one, protests occur more frequently, and they become more intensive and persistent. Group identification does not seriously influence the frequency of local uprisings. Both their strength and duration, however, are negatively affected by the ingroup-outgroup assessment. The overall findings are valid when workers distinguish \'us\' from \'them\' through simple binary categorization, as well as when they perceive degrees of similarity and difference from their neighbors.Workers Protest, Tags, Group Identity, Trust, Netlogo

Gaining confidence in models of experiments in existing buildings

Describes a method for gaining confidence in models of experiments in existing buildings

Galaxy clustering and galaxy clusters from the UKIDSS DXS

Recent wide and deep surveys allow us to investigate the large scale structure of the Universe at high redshift. We present studies of the clustering of high redshift galaxies and galaxy clusters, using reprocessed UKIDSS DXS catalogues. The UKIDSS DXS is one of the deepest near-IR surveys to date and provides sufficient samples of the distant Universe. Firstly we measure the angular correlation function of high redshift red galaxies which are Extremely Red Objects (EROs) and Distant Red Galaxies (DRGs) in Chapters 3 and 4 from DXS SA22 and Elais-N1 fields. We found that their angular correlation functions can be described by a broken power-law. Thus we estimated clustering properties on small and large scales separately. Then we found that red or bright samples are more strongly clustered than those having the opposite characteristics. In addition old, passive EROs are found to be more clustered than dusty, star-forming EROs. The effect of cosmic variance on angular clustering was also investigated. Chapter 5 describes the halo modelling for the angular clustering of EROs. EROs reside in in dark matter haloes having > 1012.9h−1M, and have a bias of 1.93 at z = 1.12 and 3.17 at z = 1.55. From a direct comparison between the observed clustering and the cosmological model, they show good agreement. However the cosmological simulation may predict too many red satellites, especially at high redshfit. In Chapter 6, we present the details of our cluster detection algorithm based on the red sequence technique. This algorithm successfully found published galaxy clusters in the DXS Elais-N1 field. We also found many overdensities in the DXS SA22 field. Two prominent galaxy clusters were confirmed by spectroscopic observations, and we identified a supercluster candidate. Finally the clustering strength of candidate galaxy clusters showed good agreement with previous results and was consistent with the ΛCDM prediction. In the near future the full DXS catalogue will provide an opportunity to detect various high redshift populations. With other advanced surveys, it will be possible to investigate more details of the large scale structure of the Universe

The Solar-Type Contact Binary BX Pegasi Revisited

We present the results of new CCD photometry for the contact binary BX Peg, made during three successive months beginning on September 2008. As do historical light curves, our observations display an O'Connell effect and the November data by themselves indicate clear evidence for very short-time brightness disturbance. For these variations, model spots are applied separately to the two data set of Group I (Sep.--Oct.) and Group II (Nov.). The former is described by a single cool spot on the secondary photosphere and the latter by a two-spot model with a cool spot on the cool star and a hot one on either star. These are generalized manifestations of the magnetic activity of the binary system. Twenty light-curve timings calculated from Wilson-Devinney code were used for a period study, together with all other minimum epochs. The complex period changes of BX Peg can be sorted into a secular period decrease caused dominantly by angular momentum loss due to magnetic stellar wind braking, a light-travel-time (LTT) effect due to the orbit of a low-mass third companion, and a previously unknown short-term oscillation. This last period modulation could be produced either by a second LTT orbit with a period of about 16 yr due to the existence of a fourth body or by the effect of magnetic activity with a cycle length of about 12 yr.Comment: 23 pages, including 6 figures and 8 tables, accepted for publication in PAS

Physical Properties of the Transiting Planetary System TrES-3

We present four new transits of the planetary system TrES-3 observed between 2009 May and 2010 June. Among these, the third transit by itself indicates possible evidence for brightness disturbance, which might be the result of the planet blocking a cool starspot on the stellar surface. A total of 109 transit times, including our measurements, were used to determine the improved ephemeris with a transit epoch of 2454185.910944$\pm$0.000072 HJED and an orbital period of 1.30618700$\pm$0.00000015 d. We analyzed the transit light curves using the JKTEBOP code and adopting the quadratic limb-darkening law. In order to derive the physical properties of the TrES-3 system, the transit parameters are combined with the empirical relations from eclipsing binary stars and stellar evolutionary models. The stellar mass and radius obtained from a calibration using $T_A$, log $\rho_{\rm A}$ and [Fe/H] are consistent with those from the isochrone analysis. We found that the exoplanet TrES-3b has a mass of 1.93$\pm$0.07 M$_{\rm Jup}$, a radius of 1.30$\pm$0.04 R$_{\rm Jup}$, a surface gravity of log $g_{\rm b}$=3.45$\pm$0.02, a density of 0.82$\pm$0.06 $\rho_{\rm Jup}$, and an equilibrium temperature of 1641$\pm$23 K. The results are in good agreement with theoretical models for gas giant planets.Comment: 15 pages, including 4 figures and 4 tables, accepted for publication in PAS