663 research outputs found

    The Moderating Effect of Family-Ownership on Firm Performance: An Examination of Entrepreneurial Orientation and Social Capital

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    Within the small business literature, a number of recent studies have examined the importance of entrepreneurial orientation (EO) and the development of social capital (SC) as each contributes to a firm's performance. While it is generally accepted in previous studies that each of these constructs positively affects firm performance, relatively less attention has been paid to potential moderating factors that can affect these relationships. The purpose of our research is to address one such moderator, family ownership. Using structural equation modeling (SEM) to test the moderating effect of family ownership on the relationships among entrepreneurial orientation, social capital, and firm performance, our results show that the effects of EO and SC vary depending upon whether the firm is family-owned or non-family owned. Implications of these findings and future research directions are provided

    Progress toward BLISS, the background-limited infrared-submillimeter spectrograph for SPICA

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    We are developing the Background-Limited Infrared-Submillimeter Spectrograph (BLISS) for SPICA to provide a breakthrough capability for far-IR survey spectroscopy. The 3.2-meter, actively-cooled (T<6K) SPICA telescope allows mid-IR to submm observations which are limited only by the natural backgrounds, and BLISS is designed to operate near this fundamental limit. BLISS-SPICA provide a line sensitivity of 10-20 W m-2 , thereby enabling spectroscopy of dust-obscured galaxies at all epochs back to the first billion years after the Big Bang (redshift 6), and study of all stages of planet formation in circumstellar disks. BLISS covers the 35-430 micron waveband at moderate resolving power (300<R<700) in six grating spec­ trometer bands, each coupling at least two 2 sky positions simultaneously. The instrument is cooled with an on-board refrigerator to 50 mK for optimal sensitivity. The detector package in the goal implementation is 4200 silicon-nitride micro-mesh leg-isolated bolometers with superconducting transition-edge-sensed (TES) thermis­tors, read out with a cryogenic time-domain multiplexer. The instrument is designed to fit within the stringent SPICA resource allocations for mass and heat lift, and to mitigate the impact of cosmic rays. We report on this design and our progress in prototyping and validating the BLISS spectrometers and prototype cooler. A companion paper in Conference 8452 (A. Beyer et al.) discusses in greater detail the progress in the BLISS TES bolometer development

    High resolution CMB power spectrum from the complete ACBAR data set

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    In this paper, we present results from the complete set of cosmic microwave background (CMB) radiation temperature anisotropy observations made with the Arcminute Cosmology Bolometer Array Receiver (ACBAR) operating at 150 GHz. We include new data from the final 2005 observing season, expanding the number of detector-hours by 210% and the sky coverage by 490% over that used for the previous ACBAR release. As a result, the band-power uncertainties have been reduced by more than a factor of two on angular scales encompassing the third to fifth acoustic peaks as well as the damping tail of the CMB power spectrum. The calibration uncertainty has been reduced from 6% to 2.1% in temperature through a direct comparison of the CMB anisotropy measured by ACBAR with that of the dipole-calibrated WMAP5 experiment. The measured power spectrum is consistent with a spatially flat, LambdaCDM cosmological model. We include the effects of weak lensing in the power spectrum model computations and find that this significantly improves the fits of the models to the combined ACBAR+WMAP5 power spectrum. The preferred strength of the lensing is consistent with theoretical expectations. On fine angular scales, there is weak evidence (1.1 sigma) for excess power above the level expected from primary anisotropies. We expect any excess power to be dominated by the combination of emission from dusty protogalaxies and the Sunyaev-Zel'dovich effect (SZE). However, the excess observed by ACBAR is significantly smaller than the excess power at ell > 2000 reported by the CBI experiment operating at 30 GHz. Therefore, while it is unlikely that the CBI excess has a primordial origin; the combined ACBAR and CBI results are consistent with the source of the CBI excess being either the SZE or radio source contamination.Comment: Submitted to ApJ; Changed to apply a WMAP5-based calibration. The cosmological parameter estimation has been updated to include WMAP

    Joint Elastic Side-Scattering Lidar and Raman Lidar Measurements of Aerosol Optical Properties in South East Colorado

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    We describe an experiment, located in south-east Colorado, USA, that measured aerosol optical depth profiles using two Lidar techniques. Two independent detectors measured scattered light from a vertical UV laser beam. One detector, located at the laser site, measured light via the inelastic Raman backscattering process. This is a common method used in atmospheric science for measuring aerosol optical depth profiles. The other detector, located approximately 40km distant, viewed the laser beam from the side. This detector featured a 3.5m2 mirror and measured elastically scattered light in a bistatic Lidar configuration following the method used at the Pierre Auger cosmic ray observatory. The goal of this experiment was to assess and improve methods to measure atmospheric clarity, specifically aerosol optical depth profiles, for cosmic ray UV fluorescence detectors that use the atmosphere as a giant calorimeter. The experiment collected data from September 2010 to July 2011 under varying conditions of aerosol loading. We describe the instruments and techniques and compare the aerosol optical depth profiles measured by the Raman and bistatic Lidar detectors.Comment: 34 pages, 16 figure

    ACBAR: The Arcminute Cosmology Bolometer Array Receiver

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    We describe the Arcminute Cosmology Bolometer Array Receiver (ACBAR); a multifrequency millimeter-wave receiver designed for observations of the Cosmic Microwave Background (CMB) and the Sunyaev-Zel'dovich effect in clusters of galaxies. The ACBAR focal plane consists of a 16-pixel, background-limited, 240 mK bolometer array that can be configured to observe simultaneously at 150, 220, 280, and 350 GHz. With 4-5' FWHM Gaussian beam sizes and a 3 degree azimuth chop, ACBAR is sensitive to a wide range of angular scales. ACBAR was installed on the 2 m Viper telescope at the South Pole in January 2001. We describe the design of the instrument and its performance during the 2001 and 2002 observing seasons.Comment: 59 pages, 16 figures -- updated to reflect version published in ApJ

    Analysis of US child care safety regulations.

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    BACKGROUND: With 1.9 million US children cared for in organized group child care, the safety of these children is a public health concern. In the absence of federal policy, each state has developed its own day care safety regulations. METHODS: After creating a set of 36 criteria from three sets of national guidelines, we assessed the safety regulations of 45 states. With a mailed survey of state day care regulatory personnel, we examined the processes of formulating and implementing safety policy in 47 states. RESULTS: For 24 of the 36 items, more than half the states' regulations were below the criteria or failed to mention the topic. Most notable is the inattention to playground safety, choking hazards, and firearms. CONCLUSION: The uneven quality of regulations may be a reflection of a regulatory process that is fragmented, with many different groups sharing authority and with limited involvement of injury prevention specialists

    Design and construction of a carbon fiber gondola for the SPIDER balloon-borne telescope

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    We introduce the light-weight carbon fiber and aluminum gondola designed for the SPIDER balloon-borne telescope. SPIDER is designed to measure the polarization of the Cosmic Microwave Background radiation with unprecedented sensitivity and control of systematics in search of the imprint of inflation: a period of exponential expansion in the early Universe. The requirements of this balloon-borne instrument put tight constrains on the mass budget of the payload. The SPIDER gondola is designed to house the experiment and guarantee its operational and structural integrity during its balloon-borne flight, while using less than 10% of the total mass of the payload. We present a construction method for the gondola based on carbon fiber reinforced polymer tubes with aluminum inserts and aluminum multi-tube joints. We describe the validation of the model through Finite Element Analysis and mechanical tests.Comment: 16 pages, 11 figures. Presented at SPIE Ground-based and Airborne Telescopes V, June 23, 2014. To be published in Proceedings of SPIE Volume 914

    SPIDER: a balloon-borne CMB polarimeter for large angular scales

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    We describe SPIDER, a balloon-borne instrument to map the polarization of the millimeter-wave sky with degree angular resolution. Spider consists of six monochromatic refracting telescopes, each illuminating a focal plane of large-format antenna-coupled bolometer arrays. A total of 2,624 superconducting transition-edge sensors are distributed among three observing bands centered at 90, 150, and 280 GHz. A cold half-wave plate at the aperture of each telescope modulates the polarization of incoming light to control systematics. Spider's first flight will be a 20-30-day Antarctic balloon campaign in December 2011. This flight will map \sim8% of the sky to achieve unprecedented sensitivity to the polarization signature of the gravitational wave background predicted by inflationary cosmology. The Spider mission will also serve as a proving ground for these detector technologies in preparation for a future satellite mission.Comment: 12 pages, 6 figures; as published in the conference proceedings for SPIE Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V (2010

    Spider Optimization: Probing the Systematics of a Large Scale B-Mode Experiment

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    Spider is a long-duration, balloon-borne polarimeter designed to measure large scale Cosmic Microwave Background (CMB) polarization with very high sensitivity and control of systematics. The instrument will map over half the sky with degree angular resolution in I, Q and U Stokes parameters, in four frequency bands from 96 to 275 GHz. Spider's ultimate goal is to detect the primordial gravity wave signal imprinted on the CMB B-mode polarization. One of the challenges in achieving this goal is the minimization of the contamination of B-modes by systematic effects. This paper explores a number of instrument systematics and observing strategies in order to optimize B-mode sensitivity. This is done by injecting realistic-amplitude, time-varying systematics in a set of simulated time-streams. Tests of the impact of detector noise characteristics, pointing jitter, payload pendulations, polarization angle offsets, beam systematics and receiver gain drifts are shown. Spider's default observing strategy is to spin continuously in azimuth, with polarization modulation achieved by either a rapidly spinning half-wave plate or a rapidly spinning gondola and a slowly stepped half-wave plate. Although the latter is more susceptible to systematics, results shown here indicate that either mode of operation can be used by Spider.Comment: 15 pages, 12 figs, version with full resolution figs available here http://www.astro.caltech.edu/~lgg/spider_front.ht
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