Vacuum-isolation vessel and method for measurement of thermal noise in microphones

The vacuum isolation vessel and method in accordance with the present invention are used to accurately measure thermal noise in microphones. The apparatus and method could be used in a microphone calibration facility or any facility used for testing microphones. Thermal noise is measured to determine the minimum detectable sound pressure by the microphone. Conventional isolation apparatus and methods have been unable to provide an acoustically quiet and substantially vibration free environment for accurately measuring thermal noise. In the present invention, an isolation vessel assembly comprises a vacuum sealed outer vessel, a vacuum sealed inner vessel, and an interior suspension assembly coupled between the outer and inner vessels for suspending the inner vessel within the outer vessel. A noise measurement system records thermal noise data from the isolation vessel assembly. A vacuum system creates a vacuum between an internal surface of the outer vessel and an external surface of the inner vessel. The present invention thus provides an acoustically quiet environment due to the vacuum created between the inner and outer vessels and a substantially vibration free environment due to the suspension assembly suspending the inner vessel within the outer vessel. The thermal noise in the microphone, effectively isolated according to the invention, can be accurately measured

The impact of regulation, ownership and business culture on managing corporate risk within the water industry

Although the specifics of water utility ownership, regulation and management culture have been explored in terms of their impact on economic and customer value, there has been little meaningful engagement with their influence on the risk environment and risk management. Using a literature review as the primary source of information, this paper maps the existing knowledge base onto two critical questions: what are the particular features of regulation, ownership and management culture which influence the risk dynamic, and what are the implications of these relationships in the context of ambitions for resilient organizations? In addressing these queries, the paper considers the mindful choices and adjustments a utility must make to its risk management strategy to manage strategic tensions between efficiency, risk and resilience. The conclusions note a gap in understanding of the drivers required for a paradigm shift within the water sector from a re-active to a pro-active risk management culture. A proposed model of the tensions between reactive risk management and pro-active, adaptive risk management provides a compelling case for measured risk management approaches which are informed by an appreciation of regulation, ownership and business culture. Such approaches will support water authorities in meeting corporate aspirations to become "high reliability" services while retaining the capacity to out-perform financial and service level targets

Understanding perceived determinants of nurses’ eating and physical activity behaviour : A theory-informed qualitative interview study

We thank Eilidh Duncan and Maria Prior for help with designing the interview topic guide. We would also like to thank all the nurses who gave their time to participate in the pilot study of the interview topic guide and the qualitative interviews. The Health Services Research Unit is funded by the Chief Scientist Office of the Scottish Government Health and Social Care Directorates. The views expressed are those of the authors alone. Funding This work was funded through a Medical Research Council doctoral training award.Peer reviewedPublisher PD

The Metallicity Dependence of the Fourier Components of RR Lyrae Light Curves is the Oosterhoff/Arp/Preston Period Ratio Effect in Disguise

The correlation of particular Fourier components of the light curves of RR Lyrae variables with metallicity, discovered by Simon and later by Kovacs and his coworkers, is shown to have the same explanation as the period ratios (period shifts in log P) between RRab Lyrae variables that have the same colors, amplitudes, and light-curve shapes but different metallicities. A purpose of this paper is to demonstrate that the model which predicts the period-metallicity relations is the mediating parameters of colors, amplitudes, and light-curve shapes also explains the Simon/Kovacs et al. correlation between period, Phi_31, and metallicity. The proof is made by demonstrating that the combination of the first and third phase terms in a Fourier decomposition of RRab light curves, called Phi_31 by Simon and Lee, varies monotonically across the RR Lyrae instability strip in the same way that amplitude, color, and rise time vary with period within the strip. The premise of the model is that if horizontal branches at the RR Lyrae strip are stacked in luminosity according to the metallicity, then there necessarily must be a log period shift between RR Lyraes with different metallicities at the same Phi_31 values. However, there are exceptions to the model. (...)Comment: 17 pages, 8 figures, 1 table. Accepted for publication in The A

The Effect of Incumbent Bidding in Set-Aside Auctions: An Analysis of Prices in the Closed and Open Segments of FCC Auction 35

This paper examines the impact of an incumbent carrier’s participation in two simultaneously conducted auctions: one set-aside for non-incumbents and one open to all carriers. This paper estimates the extent to which prices in the closed auction were inflated by the participation of incumbents. This paper also estimates what prices would have been in the open auction had incumbents been excluded from bidding in the closed. It is found that an incumbent’s participation in the closed auction through a front, Alaska Native, enabled it to win more licenses at lower prices in FCC Auction 35. In contrast, non-incumbents won fewer licenses and paid more for what they won. The econometric techniques employed here to estimate prices in a “but for” world could be replicated in future damage analysis. Finally, this paper suggests an alternative method of screening bidders seeking access to set-aside auctions that would be consistent with the FCC’s goal of promoting competition in the wireless industry.Auctions, spectrum auctions, market design

Modeling Technical Change in Midwest Corn Yields, 1895-2005: A Time Varying-Regression Approach

This paper explores the use of time-varying regression models to model the effects of technical change in US Midwest Corn yields. The data extends from 1895 to 2005 encompassing the implementation of hybrid technologies and improvements in farm production practices.time-vary regression model, modeling technical change, corn yield technical change, Crop Production/Industries,