Bose-Einstein Condensation of Dark Matter Axions

We show that cold dark matter axions thermalize and form a Bose-Einstein condensate. We obtain the axion state in a homogeneous and isotropic universe, and derive the equations governing small axion perturbations. Because they form a BEC, axions differ from ordinary cold dark matter in the non-linear regime of structure formation and upon entering the horizon. Axion BEC provides a mechanism for the production of net overall rotation in dark matter halos, and for the alignment of cosmic microwave anisotropy multipoles.Comment: 4 pages. Three typos are corrected. Version to be published by Physical Review Letter

Development of a novel virtual coordinate measuring machine

Existing VCMMs (virtual coordinate measuring machine) have been mainly developed to either simulate the measurement process hence enabling the off-line programming, or to perform error analysis and uncertainty evaluation. Their capability and performance could be greatly improved if there is a complete solution to cover the whole process and provide an integrated environment. The aim of this study is to develop such a VCMM that not only supports measurement process simulation, but also performs uncertainty evaluation. It makes use of virtual reality techniques to provide an accurate model of a physical CMM, together with uncertainty evaluation. An interface is also provided to communicate with CMM controller, allowing the measuring programs generated and simulated in the VCMM to be executed or tested on the physical CMM afterwards. This paper discusses the proposal of a novel VCMM design and the preliminary results

Design, implementation, and testing of advanced virtual coordinate-measuring machines

Copyright @ 2011 IEEE. This article has been made available through the Brunel Open Access Publishing Fund.Advanced virtual coordinate-measuring machines (CMMs) (AVCMMs) have recently been developed at Brunel University, which provide vivid graphical representation and powerful simulation of CMM operations, together with Monte-Carlo-based uncertainty evaluation. In an integrated virtual environment, the user can plan an inspection strategy for a given task, carry out virtual measurements, and evaluate the uncertainty associated with the measurement results, all without the need of using a physical machine. The obtained estimate of uncertainty can serve as a rapid feedback for the user to optimize the inspection plan in the AVCMM before actual measurements or as an evaluation of the measurement results performed. This paper details the methodology, design, and implementation of the AVCMM system, including CMM modeling, probe contact and collision detection, error modeling and simulation, and uncertainty evaluation. This paper further reports experimental results for the testing of the AVCMM

[Review of] George Anthony Peffer. If They Don\u27t Bring Their Women Here: Chinese Female Immigration Before Exclusion

If They Don\u27t Bnng [Bring] Their Women Here by George Peffer is another significant addition to the skimpy repertory of books on the history of Chinese American women, which includes Judy Yung\u27s Chinese Women of America (1986) and Unbounded Feet (1995), Benson Tong\u27s Unsubmissive Women (1994), and Huping Ling\u27s Surviving on the Gold Mountain (1999). Unlike the other volumes, Peffer\u27s book focuses on the debarment of Chinese women from immigration to the United States before the 1882 general exclusion of Chinese laborers. He argues that the cultural constraints imposed by the traditional Chinese joint family structure and the male sojourner mentality did not suffice to induce the protracted shortage of Chinese female immigrants and that the Page Law of 1875 and its enforcement played a more pivotal role in restricting the immigration of Chinese women. Using data from U.S. government documents, court records, and newspapers, he documents with some measure of success that although the Page Law literally forbade only the entry of prostitutes (including Chinese ones), the broader applicationof this law resulted in a de facto exclusion of Chinese female immigrants during the seven years prior to the Chinese Exclusion Act of 1882. Peffer also demonstrates how California\u27s anti-Chinese press shaped and intensified the expanded application of the Page Law, how the anti-Chinese sentiment led to the possible overcounting of Chinese prostitutes in San Francisco in the 1870 and 1880 censuses, and how the de facto Chinese female exclusion engendered the lopsided development of the Chinese community. By piecing the scattered information together, this book enhances our understanding of the causes of the Chinese bachelor\u27s society\u27 as well as the experiences of Chinese female immigrants before the Chinese exclusion