Search

We have examined high accuracy radial velocities of Cepheids to determine the binary frequency. The data are largely from the CORAVEL spectrophotometer and the Moscow version, with a typical uncertainty of $\leq1$~km~s$^{-1}$, and a time span from 1 to 20 years. A systemic velocity was obtained by removing the pulsation component using a high order Fourier series. From this data we have developed a list of stars showing no orbital velocity larger than $\pm1$~km~s$^{-1}$. The binary fraction was analyzed as a function of magnitude, and yields an apparent decrease in this fraction for fainter stars. We interpret this as incompleteness at fainter magnitudes, and derive the preferred binary fraction of $29\pm8$\% ( $20\pm6$\% per decade of orbital period) from the brightest 40 stars. Comparison of this fraction in this period range (1-20 years) implies a large fraction for the full period range. This is reasonable in that the high accuracy velocities are sensitive to the longer periods and smaller orbital velocity amplitudes in the period range sampled here. Thus the Cepheid velocity sample provides a sensitive detection in the period range between short period spectroscopic binaries and resolved companions. The recent identification of $\delta$ Cep as a binary with very low amplitude and high eccentricity underscores the fact that the binary fractions we derive are lower limits, to which other low amplitude systems will probably be added. The mass ratio (q) distribution derived from ultraviolet observations of the secondary is consistent with a flat distribution for the applicable period range (1 to 20 years)., Comment: accepted for publication in AJ

Aboriginally is a matter of family connections and a history of marginalisation and disadvantage. Aboriginal health and social inclusion are intractable problems for government. This project contributes to redressing family violence and social inclusion issues through participatory action research (PAR) with Neporendi Forum Inc (an Aboriginal organization) to enhance social justice. The research enables an integration of activities across networks that span researchers based at two universities, local youth organizations, schools and local government (see Fals-Borda & Rathman, 1991; Edgar 2001; Duhl 2001). PAR builds the capacity of participants to work holistically across the organizations and community settings. It is sustainable, addresses socio-economic concerns and uses an intergenerational and interactive design.

This study econometrically examines the determinants of California parimutuel horseracing activity, including the effect on parimutuel wagering and attendance levels of such economic and policy-rel...

Background With the information explosion, the retrieval of the best clinical evidence from large, general purpose, bibliographic databases such as MEDLINE can be difficult. Both researchers conducting systematic reviews and clinicians faced with a patient care question are confronted with the daunting task of searching for the best medical literature in electronic databases. Many have advocated the use of search filters or "hedges" to assist with the searching process. The purpose of this report is to describe the design and methods of a study that set out to develop optimal search strategies for retrieving sound clinical studies of health disorders in large electronics databases. Objective To describe the design and methods of a study that set out to develop optimal search strategies for retrieving sound clinical studies of health disorders in large electronic databases. Design An analytic survey comparing hand searches of 170 journals in the year 2000 with retrievals from MEDLINE, EMBASE, CINAHL, and PsycINFO for candidate search terms and combinations. The sensitivity, specificity, precision, and accuracy of unique search terms and combinations of search terms were calculated. Conclusion A study design modeled after a diagnostic testing procedure with a gold standard (the hand search of the literature) and a test (the search terms) is an effective way of developing, testing, and validating search strategies for use in large electronic databases.

The techniques of steady visual fixation and repetitious auditory input are used in the laboratory for investigating perceptual phenomena and in yoga and meditation for facilitating altered states of awareness. Phenomena related to mild sensory deprivation are reported in both circumstances.

Economic historians should thank Larry Neal for his careful revision of the United States railroad investment series for the period between 1897 and 1914 [5]. However, the second major part of his article concerning the determinants of investmenit behavior over this period suffers from deficiencies of interpretation and requires further analysis which is the object of this note. Neal's thesis is that financial models, incorporating interest rates and cash flow variables, better explain railroad investment expenditures over this period than crude acceleration type mechanisms. In fact, he argues the time period 1897 to 1914 logically can be divided into two periods at the year 1907. In the earlier period (1897-1907) Neal argues that both easy access to external funds and the better use of internal funds are the primary explanations for investment behavior, while this was not the case after 1907. This thesis directly contradicts the earlier discussion of railroad investment made by Jan Kmenta and Jeffrey Williamson (K-W) [4]. The K-XV hypothesis purports that external costs were not important during this period and some sort of acceleration mechanism can best explain investment behavior. It is demonstrated below that the dominant determinant of long run railroad investment behavior over this period is the acceleration principle as asserted by K-W but that outside (as opposed to Neal's inside) financial conditions (the demand for financial instruments) contributed to the cyclical fluctuations of investment expenditures in the period prior to 1907.