9,698 research outputs found
Charge Management for Gravitational Wave Observatories using UV LEDs
Accumulation of electrical charge on the end mirrors of gravitational wave
observatories, such as the space-based LISA mission and ground-based LIGO
detectors, can become a source of noise limiting the sensitivity of such
detectors through electronic couplings to nearby surfaces. Torsion balances
provide an ideal means for testing gravitational wave technologies due to their
high sensitivity to small forces. Our torsion pendulum apparatus consists of a
movable Au-coated Cu plate brought near a Au-coated Si plate pendulum suspended
from a non-conducting quartz fiber. A UV LED located near the pendulum
photoejects electrons from the surface, and a UV LED driven electron gun
directs photoelectrons towards the pendulum surface. We have demonstrated both
charging and discharging of the pendulum with equivalent charging rates of
, as well as spectral measurements of the pendulum
charge resulting in a white noise level equivalent to .Comment: 5 pages, submitted to PR
High Sensitivity Torsion Balance Tests for LISA Proof Mass Modeling
We have built a highly sensitive torsion balance to investigate small forces
between closely spaced gold coated surfaces. Such forces will occur between the
LISA proof mass and its housing. These forces are not well understood and
experimental investigations are imperative. We describe our torsion balance and
present the noise of the system. A significant contribution to the LISA noise
budget at low frequencies is the fluctuation in the surface potential
difference between the proof mass and its housing. We present first results of
these measurements with our apparatus.Comment: 6th International LISA Symposiu
A Demonstration of LISA Laser Communication
Over the past few years questions have been raised concerning the use of
laser communications links between sciencecraft to transmit phase information
crucial to the reduction of laser frequency noise in the LISA science
measurement. The concern is that applying medium frequency phase modulations to
the laser carrier could compromise the phase stability of the LISA fringe
signal. We have modified the table-top interferometer presented in a previous
article by applying phase modulations to the laser beams in order to evaluate
the effects of such modulations on the LISA science fringe signal. We have
demonstrated that the phase resolution of the science signal is not degraded by
the presence of medium frequency phase modulations.Comment: minor corrections found in the CQG versio
Extreme tunability of interactions in a Li Bose-Einstein condensate
We use a Feshbach resonance to tune the scattering length a of a
Bose-Einstein condensate of 7Li in the |F = 1, m_F = 1> state. Using the
spatial extent of the trapped condensate we extract a over a range spanning 7
decades from small attractive interactions to extremely strong repulsive
interactions. The shallow zero-crossing in the wing of the Feshbach resonance
enables the determination of a as small as 0.01 Bohr radii. In this regime,
evidence of the weak anisotropic magnetic dipole interaction is obtained by
comparison with different trap geometries
Assessing Sport-Sales Training Effectiveness: To Enhance Sales Performance of Prospective Sales Employees
The majority of entry-level positions within the sport industry fall in the area of sales. Yet, only recently have sportmanagement programs begun to offer courses devoted to sales education and training. The discipline of sales provides an ideal opportunity to incorporate experiential-based learning. While several recent articles have examined the application of experiential-learning to courses focused on ticket sales, this article presents the results of the first systematic assessment of such courses’ effectiveness. Specifically, this paper presents the results of an evaluation of sales-training programs that incorporate Southall, Nagel, LeGrande, and Han’s (2003) metadiscrete experiential learning model and the application of this model to a sport-sales specific curriculum as presented by Irwin, Southall and Sutton (2007). Among sampled students (N = 261), survey results revealed significant differences in all assessed categories related to students’ knowledge, skills and attitudes related to sport sales. This article discusses study findings and significance of conclusions for future sport-management program development
An Enhanced Model for Managing Change in Organizations
Change has become a “way of life” in organizations. The pace of change has increased substantially in recent years as a result of issues such as the pressures of global competition the impact of the Internet, customer demands and ever changing enhancement of technical capabilities. These changes affect what people do and how they fulfill their responsibilities, and therefore, there are varied reactions Historically, failures in change implementation have not been attributable to a lack of technical feasibility and functionality but instead have been the result of employee resistance. The difficulty of implementing organizational change has presented an ongoing challenge to managers. As we anticipate the future, paramount technological changes and shifts in strategies as a result of innovations such as cloud computing, social networks, and smart phones are on the horizon, all of which provide numerous opportunities for marketers. Customer relationship management (CRM implementation in particular, warrants consideration of a change management strategy. This paper reviews severa successful change management and implementation strategies that have been utilized to address technologica change and proposes an enhanced model to guide managers as they deal with technology-based organizational changes
Obesity, mortality, and life years lost associated with breast cancer in nonsmoking US women, national health interview survey, 1997-2000
INTRODUCTION: The relationship between obesity and breast cancer has been extensively investigated. However, how obesity and breast cancer interplay to affect mortality and life expectancy of women in the United States has not been well studied. METHODS: We used data from the National Health Interview Survey, 1997–2000. Our sample included nonsmoking, nonpregnant women who reported a body mass index of at least 18.5 kg/m(2) and no cancer other than breast cancer at the time of the survey. A survival model with Gamma frailty and Gompertz baseline was used to estimate relative risks of total mortality and project life years lost associated with breast cancer by obesity status and age. RESULTS: Breast cancer increased risk of mortality depending on degree of obesity and decreased life years by 1 to 12 years depending on race, age, and obesity status. Relative risks for death increased with degree of obesity. Obese women under age 50 across all racial groups were predicted to lose the most life years; racial groups other than whites and blacks lost the most life years (11.9 y), followed by whites (9.8 y) and blacks (9.2 y). CONCLUSION: The number of life years lost associated with breast cancer was more marked for more obese than for less obese women and for women under age 50 and women aged 70 or older than for women aged 50 through 69. Public health initiatives should put more emphasis on the prevention and control of obesity for these target populations
VLBI Polarimetry of 177 Sources from the Caltech-Jodrell Bank Flat-spectrum Survey
We present VLBA observations and a statistical analysis of 5 GHz VLBI
polarimetry data from 177 sources in the Caltech-Jodrell Bank flat-spectrum
(CJF) survey. The CJF survey, a complete, flux-density-limited sample of 293
extragalactic radio sources, gives us the unique opportunity to compare a broad
range of source properties for quasars, galaxies and BL Lacertae objects. We
focus primarily on jet properties, specifically the correlation between the jet
axis angle and the polarization angle in the core and jet. A strong correlation
is found for the electric vector polarization angle in the cores of quasars to
be perpendicular to the jet axis. Contrary to previous claims, no correlation
is found between the jet polarization angle and the jet axis in either quasars
or BL Lac objects. With this large, homogeneous sample we are also able to
investigate cosmological issues and AGN evolution.Comment: Accepted to the Astrophysical Journal: 37 pages, 14 figure
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