Dark Left-Right Model: CDMS, LHC, etc

The Standard Model of particle interactions is extended to include fermion doublets (n,e)_R transforming under the gauge group SU(2)_R such that n is a Dirac scotino (dark-matter fermion), with odd R parity. Based on recent CDMS data, it is shown how this new dark left-right model (DLRM2) favors a Z' gauge boson at around 1 or 2 TeV and be observable at the LHC. The new W_R gauge bosons may also contribute significantly to lepton-flavor-changing processes such as mu to e gamma and mu-e conversion in a nucleus or muonic atom.Comment: 7 pages, 4 figures, typo corrected, talk at Dark Side of Universe 2010, Leon, Mexic

IMPACTS OF INCOME CHANGES AND MODEL SPECIFICATION ON FOOD DEMAND IN URBAN CHINA

Functional form specification is a crucial task in demand analysis. Four food demand systems for 12 aggregated food items in urban China are estimated and compared using province level data for the period 1992-1999. The results show the expenditure elasticities especially for grain are different based on the functional form selection. According to the measures of forecasting accuracy, we conclude the following: for ex post simulation, the simpler the models, the better the performances, whereas for ex ante forecasting, the more complicated the model, the better the predictions. We further conclude that the LES and QES outperform the LA/AIDS and AIDS. Therefore, model selection should depend on the study purpose. In addition, as urban Chinese household income increases, they will consume more aquatic products, poultry and milk than other foods. This potential trend will certainly benefit the fishery and livestock industries as well as feed grain producers in China or other countries such as Taiwan. However, high own-price elasticities of these three food groups suggest that the profitability of suppliers and traders is very sensitive to price changes.Demand and Price Analysis,

FOOD DEMAND IN URBAN CHINA: AN APPLICATION OF A MULTI-STAGE CENSORED DEMAND SYSTEM

Since its economic reform, China has changed significantly as it makes its transition from a centrally-planned to a consumer-oriented economy and thus has gradually increased household income and changed consumption patterns in urban China. This study attempts to provide an in-depth understanding of heterogeneous consumer patterns in urban China by developing a multi-stage censored demand system using household data. Specifically, this study develops an economic model considering heterogeneous consumption patterns across households and commodity groupings and estimates econometric models of a Quadratic Almost Ideal Demand System (QAIDS) using household data. Three methodologies are integrated including constructing a multi-stage demand system, incorporating demographic variables using the 'ordinary budget share scaling and translation' (OBSSAT), and employing a two-step estimator to deal with zero consumption problems. This study covers three provinces in China, Shandong, Jiangsu, and Guangdong, and uses household data from 1998 provided by the National Bureau of Statistics (NBS). Based on the Chinese food guide pyramid, a three-level utility tree is constructed dividing 18 food items into five subgroups. An empirical analysis is conducted by estimating econometric models to examine the impact of the potential factors, e.g., income and demographic variables, on food demand. The results show the uniqueness of this study in three dimensions. First, using the OBSSAT helps answer the question of "how to break down the heterogeneous consumption patterns in urban China?" In addition, our findings also show that China should be treated as several markets instead of one. Second, the QAIDS has not previously been applied to the study of food demand in urban China. Our results show that the QAIDS is superior to the AIDS; however, the degree of importance for the quadratic term decreases as demographic and censoring effects are considered in a demand system. Finally, 18 food items are broken down into five food subgroups and are estimated by a multi-stage censored QAIDS. Including this large food bundle in a demand system provides us detailed information of the relationship among food items.Demand and Price Analysis,

TRANSLATING AND SCALING OF BUDGET SHARES: AN EMPIRICAL ANALYSIS OF CHINESE URBAN HOUSEHOLD DEMAND FOR MEAT

The importance of incorporating demographic effects into a demand system is demonstrated using Lewbel's unified functions. In this study, the empirical analysis of meat demand in urban China shows the benefit of utilizing the translation and scaling of budget shares.Demand and Price Analysis,

FREQ: A computational package for multivariable system loop-shaping procedures

Many approaches in the field of linear, multivariable time-invariant systems analysis and controller synthesis employ loop-sharing procedures wherein design parameters are chosen to shape frequency-response singular value plots of selected transfer matrices. A software package, FREQ, is documented for computing within on unified framework many of the most used multivariable transfer matrices for both continuous and discrete systems. The matrices are evaluated at user-selected frequency-response values, and singular values against frequency. Example computations are presented to demonstrate the use of the FREQ code

Robust multivariable controller design for flexible spacecraft

Large, flexible spacecraft are typically characterized by a large number of significant elastic modes with very small inherent damping, low, closely spaced natural frequencies, and the lack of accurate knowledge of the structural parameters. Summarized here is some recent research on the design of robust controllers for such spacecraft, which will maintain stability, and possible performance, despite these problems. Two types of controllers are considered, the first being the linear-quadratic-Gaussian-(LQG)-type. The second type utilizes output feedback using collocated sensors and actuators. The problem of designing robust LQG-type controllers using the frequency domain loop transfer recovery (LTR) method is considered, and the method is applied to a large antenna model. Analytical results regarding the regions of stability for LQG-type controllers in the presence of actuator nonlinearities are also presented. The results obtained for the large antenna indicate that the LQG/LTR method is a promising approach for control system design for flexible spacecraft. For the second type of controllers (collocated controllers), it is proved that the stability is maintained in the presence of certain commonly encountered nonlinearities and first-order actuator dynamics. These results indicate that collocated controllers are good candidates for robust control in situations where model errors are large