Herwig++ 2.0 Release Note

A new release of the Monte Carlo program Herwig++ (version 2.0) is now available. This is the first version of the program which can be used for hadron-hadron physics and includes the full simulation of both initial- and final-state QCD radiation.Comment: Source code and additional information available at http://hepforge.cedar.ac.uk/herwig

Mass media destabilizes the cultural homogeneous regime in Axelrod's model

An important feature of Axelrod's model for culture dissemination or social influence is the emergence of many multicultural absorbing states, despite the fact that the local rules that specify the agents interactions are explicitly designed to decrease the cultural differences between agents. Here we re-examine the problem of introducing an external, global interaction -- the mass media -- in the rules of Axelrod's model: in addition to their nearest-neighbors, each agent has a certain probability $p$ to interact with a virtual neighbor whose cultural features are fixed from the outset. Most surprisingly, this apparently homogenizing effect actually increases the cultural diversity of the population. We show that, contrary to previous claims in the literature, even a vanishingly small value of $p$ is sufficient to destabilize the homogeneous regime for very large lattice sizes

On the Nature of Incompressible Magnetohydrodynamic Turbulence

A novel model of incompressible magnetohydrodynamic turbulence in the presence of a strong external magnetic field is proposed for explanation of recent numerical results. According to the proposed model, in the presence of the strong external magnetic field, incompressible magnetohydrodynamic turbulence becomes nonlocal in the sense that low frequency modes cause decorrelation of interacting high frequency modes from the inertial interval. It is shown that the obtained nonlocal spectrum of the inertial range of incompressible magnetohydrodynamic turbulence represents an anisotropic analogue of Kraichnan's nonlocal spectrum of hydrodynamic turbulence. Based on the analysis performed in the framework of the weak coupling approximation, which represents one of the equivalent formulations of the direct interaction approximation, it is shown that incompressible magnetohydrodynamic turbulence could be both local and nonlocal and therefore anisotropic analogues of both the Kolmogorov and Kraichnan spectra are realizable in incompressible magnetohydrodynamic turbulence.Comment: Physics of Plasmas (Accepted). A small chapter added about 2D MHD turbulenc

Development of a carbon fibre composite active mirror: Design and testing

Carbon fibre composite technology for lightweight mirrors is gaining increasing interest in the space- and ground-based astronomical communities for its low weight, ease of manufacturing, excellent thermal qualities and robustness. We present here first results of a project to design and produce a 27 cm diameter deformable carbon fibre composite mirror. The aim was to produce a high surface form accuracy as well as low surface roughness. As part of this programme, a passive mirror was developed to investigate stability and coating issues. Results from the manufacturing and polishing process are reported here. We also present results of a mechanical and thermal finite element analysis, as well as early experimental findings of the deformable mirror. Possible applications and future work are discussed.Comment: Accepted by Optical Engineering. Figures 1-7 on http://www.star.ucl.ac.uk/~sk/OEpaper_files

Phase-sensitive wavelength conversion based on cascaded quadratic processes in periodically poled lithium niobate waveguides

We propose and experimentally demonstrate a novel scheme of phase-sensitive wavelength conversion, based on a combination of cascaded second-order nonlinear effects in two cascaded periodically poled lithium niobate waveguides

Characterizing the Rigidly Rotating Magnetosphere Stars HD 345439 and HD 23478

The SDSS III APOGEE survey recently identified two new $\sigma$ Ori E type candidates, HD 345439 and HD 23478, which are a rare subset of rapidly rotating massive stars whose large (kGauss) magnetic fields confine circumstellar material around these systems. Our analysis of multi-epoch photometric observations of HD 345439 from the KELT, SuperWASP, and ASAS surveys reveals the presence of a $\sim$0.7701 day period in each dataset, suggesting the system is amongst the faster known $\sigma$ Ori E analogs. We also see clear evidence that the strength of H-alpha, H I Brackett series lines, and He I lines also vary on a $\sim$0.7701 day period from our analysis of multi-epoch, multi-wavelength spectroscopic monitoring of the system from the APO 3.5m telescope. We trace the evolution of select emission line profiles in the system, and observe coherent line profile variability in both optical and infrared H I lines, as expected for rigidly rotating magnetosphere stars. We also analyze the evolution of the H I Br-11 line strength and line profile in multi-epoch observations of HD 23478 from the SDSS-III APOGEE instrument. The observed periodic behavior is consistent with that recently reported by Sikora and collaborators in optical spectra.Comment: Accepted in ApJ

Malaria, Intestinal Parasitic Infection, Anemia, and Malnourishment in Rural Cameroonian Villages with an Assessment of Early Interventions

Malaria, water-borne diarrheal diseases, and geohelminth infections, combined with severe malnutrition ravage entire villages throughout subSaharan Africa. The Bawa Health Initiative (BHI) is a 501c(3) non-profit organization with the goal of implementing a comprehensive public health program in an attempt to address these problems in a series of rural villages located in the West Province of Cameroon, Africa. Interventions include the provision of permethrin-treated bed nets to reduce the transmission of malaria, the installation of biosand water filters to reduce the prevalence of water-borne diseases, and a geohelminth control program utilizing mass treatment with albendazole. This study details the results of surveys conducted to monitor the success of the interventions. Since implementation of interventions, the number of clinical cases of malaria, diarrheal disease and typhoid has decreased, the prevalence of water-borne protozoan parasites has decreased, the prevalence and intensities of geohelminth infections has significantly decreased, and the prevalence of anemia has significantly decreased. When viewed in its entirety, these data show that the comprehensive approach to public health challenges in these villages initiated by BHI has been extremely successful. However, much work remains to be done. The primary purpose of this paper is to further inform academicians, students, and the general public about the continuing problems associated with these diseases and to describe and assess the effectiveness of some current interventions being used to combat them

Electron-Temperature Measurement In Laser-Produced Plasmas By The Ratio Of Isoelectronic Line-Intensities

A class of spectroscopic line ratios has been adapted as a diagnostic of electron temperature from \u3c 100 eV to \u3e 1 keV. The diagnostic makes use of the ratio of line intensities from isoelectronic states of different elements in specially prepared targets. The diagnostic is simple to interpret, shows weak dependence on plasma density, requires only low to moderate spectral resolution, uses a single charge state, and can be adapted to minimize line reabsorption and wavelength coincidences with other spectral lines. We present theoretical and experimental results

All-optical phase-regenerative multicasting of 40 Gbit/s DPSK signal in a degenerate phase sensitive amplifier

We demonstrate all-optical 1-to-5 differential phase-shift keyed (DPSK) wavelength multicasting at 40 Gbit/s using a degenerate four-wave mixing (FWM) based phase sensitive amplifier (PSA). Phase regenerative properties are reported with a sensitivity improvement of more that 10 dB

Saturation effects in degenerate phase sensitive fiber optic parametric amplifiers

We experimentally study saturation effects in degenerate phase sensitive amplifiers, revealing and explaining a gain regime suitable for all-optical signal processing functions such as phase regeneration