40,409 research outputs found
Testing the Effectiveness of Regulation and Competition on Cable Television Rates
Regulation of the cable television industry was marked by remarkable periods of deregulation, re-regulation, and re-deregulation during the 1980s and 1990s. Using FCC firm-level survey data spanning 1993 to 2001, we model and econometrically estimate the effect of regulation and competition on cable rates. Our calculations indicate that while regulation lowered rates for small system operators, it raised them for medium and large systems. Meanwhile, competition consistently decreased rates from 5.6 to 8.8 percent, with even larger declines during periods of regulation. Our results suggest that competition is more effective than regulation in containing cable prices.cable rates, regulation, competition
Testing the Effectiveness of Regulation and Competition on Cable Television Rates
Regulation of the cable television industry was marked by remarkable periods of deregulation, re-regulation, and re-deregulation during the 1980s and 1990s. Using FCC firm-level survey data spanning 1993 to 2001, we model and econometrically estimate the effect of regulation and competition on cable rates. Our calculations indicate that while regulation lowered rates for small system operators, it raised them for medium and large systems. Meanwhile, competition consistently decreased rates from 5.6 to 8.8 percent, with even larger declines during periods of regulation. Our results suggest that competition is more effective than regulation in containing cable prices.cable rates, regulation, competition
In-trail dynamics of multiple CDTI-equipped aircraft queues
One of the potential problems of in-trail self-spacing with a Cockpit Display of Traffic Information (CDTI) is whether dynamic oscillations would occur in a queue of aircraft flying an approach, similar to the ""accordion'' effect seem with the queue of automobiles in stop-and-go traffic. In order to gain some insight into this potential problem, a brief experiment was conducted with the Transport Systems Research Vehicle (TSRV) ground-based simulator equipped with CDTI which presented the position of other aircraft in the area. Three simulation sessions were conducted wherein queues of up to nine aircraft were built, each one self-spacing on the preceding aircraft. The aircraft crews were rotated to ensure that the pilots had no prior knowledge of the lead aircraft behavior they would be following. Two different spacing criteria were employed: a constant time predictor criterion and a constant time delay criterion. The experiment failed to uncover any dynamic oscillatory tendencies in queues of seven to nine aircraft
Systematic review of the effects of exercise and nutrition interventions on body composition in women with metastatic breast cancer
Uncoupling of p97 ATPase activity has a dominant negative effect on protein extraction
p97 is a highly abundant, homohexameric AAA+ ATPase that performs a variety of essential cellular functions. Characterized as a ubiquitin-selective chaperone, p97 recognizes proteins conjugated to K48-linked polyubiquitin chains and promotes their removal from chromatin and other molecular complexes. Changes in p97 expression or activity are associated with the development of cancer and several related neurodegenerative disorders. Although pathogenic p97 mutations cluster in and around p97's ATPase domains, mutant proteins display normal or elevated ATPase activity. Here, we show that one of the most common p97 mutations (R155C) retains ATPase activity, but is functionally defective. p97-R155C can be recruited to ubiquitinated substrates on chromatin, but is unable to promote substrate removal. As a result, p97-R155C acts as a dominant negative, blocking protein extraction by a similar mechanism to that observed when p97's ATPase activity is inhibited or inactivated. However, unlike ATPase-deficient proteins, p97-R155C consumes excess ATP, which can hinder high-energy processes. Together, our results shed new insight into how pathogenic mutations in p97 alter its cellular function, with implications for understanding the etiology and treatment of p97-associated diseases
Observing mergers of non-spinning black-hole binaries
Advances in the field of numerical relativity now make it possible to
calculate the final, most powerful merger phase of binary black-hole
coalescence for generic binaries. The state of the art has advanced well beyond
the equal-mass case into the unequal-mass and spinning regions of parameter
space. We present a study of the nonspinning portion of parameter space,
primarily using an analytic waveform model tuned to available numerical data,
with an emphasis on observational implications. We investigate the impact of
varied mass ratio on merger signal-to-noise ratios (SNRs) for several
detectors, and compare our results with expectations from the test-mass limit.
We note a striking similarity of the waveform phasing of the merger waveform
across the available mass ratios. Motivated by this, we calculate the match
between our 1:1 (equal mass) and 4:1 mass-ratio waveforms during the merger as
a function of location on the source sky, using a new formalism for the match
that accounts for higher harmonics. This is an indicator of the amount of
degeneracy in mass ratio for mergers of moderate-mass-ratio systems.Comment: 13 pages, 11 figures, submitted to Phys. Rev.
BĂĽchwald-Hartwig reaction applied to synthesis of new luminescent liquid crystal triarylamines derived from isoxazoles
© 2015 Taylor & Francis Group, LLC. The present work describes the synthesis and characterization of novel series of triarylamines isoxazoles (TAA) addressed to the organic photovoltaic materials. Diarylisoxazoles were synthesized by sequential [3+2] 1,3-dipolar cycloaddition reaction between arylnitrile oxides and selected arylalkenes followed by MnO2-oxidation. Isoxazoles were coupled to diarylamines by Büchwald-Hartwig reaction to afford desired compounds 6a-k. Some TAA display liquid-crystalline behaviour and UV-Vis absorption and fluorescence emission were analysed for all samples of TAA 6a-k
Tensor-Scalar Torsion
A theory of gravity with torsion is examined in which the torsion tensor is
constructed from the exterior derivative of an antisymmetric rank two potential
plus the dual of the gradient of a scalar field. Field equations for the theory
are derived by demanding that the action be stationary under variations with
respect to the metric, the antisymmetric potential, and the scalar field. A
material action is introduced and the equations of motion are derived. The
correct conservation law for rotational angular momentum plus spin is observed
to hold in this theory.Comment: 10 pages, LaTeX, Mod. Phys. Lett. A accepte
Physiotherapy students\u27 perceptions and experiences of clinical prediction rules
Objectives: Clinical reasoning can be difficult to teach to pre-professional physiotherapy students due to their lack of clinical experience. It may be that tools such as clinical prediction rules (CPRs) could aid the process, but there has been little investigation into their use in physiotherapy clinical education. This study aimed to determine the perceptions and experiences of physiotherapy students regarding CPRs, and whether they are learning about CPRs on clinical placement.
Design: Cross-sectional survey using a paper-based questionnaire.
Participants: Final year pre-professional physiotherapy students (n=371, response rate 77%) from five universities across five states of Australia.
Results: Sixty percent of respondents had not heard of CPRs, and a further 19% had not clinically used CPRs. Only 21% reported using CPRs, and of these nearly three-quarters were rarely, if ever, learning about CPRs in the clinical setting. However most of those who used CPRs (78%) believed CPRs assisted in the development of clinical reasoning skills and none (0%) was opposed to the teaching of CPRs to students. The CPRs most commonly recognised and used by students were those for determining the need for an X-ray following injuries to the ankle and foot (67%), and for identifying deep venous thrombosis (63%).
Conclusions: The large majority of students in this sample knew little, if anything, about CPRs and few had learned about, experienced or practiced them on clinical placement. However, students who were aware of CPRs found them helpful for their clinical reasoning and were in favour of learning more about them
Debye relaxation in high magnetic fields
Dielectric relaxation is universal in characterizing polar liquids and
solids, insulators, and semiconductors, and the theoretical models are well
developed. However, in high magnetic fields, previously unknown aspects of
dielectric relaxation can be revealed and exploited. Here, we report low
temperature dielectric relaxation measurements in lightly doped silicon in high
dc magnetic fields B both parallel and perpendicular to the applied ac electric
field E. For B//E, we observe a temperature and magnetic field dependent
dielectric dispersion e(w)characteristic of conventional Debye relaxation where
the free carrier concentration is dependent on thermal dopant ionization,
magnetic freeze-out, and/or magnetic localization effects. However, for BperpE,
anomalous dispersion emerges in e(w) with increasing magnetic field. It is
shown that the Debye formalism can be simply extended by adding the Lorentz
force to describe the general response of a dielectric in crossed magnetic and
electric fields. Moreover, we predict and observe a new transverse dielectric
response EH perp B perp E not previously described in magneto-dielectric
measurements. The new formalism allows the determination of the mobility and
the ability to discriminate between magnetic localization/freeze out and
Lorentz force effects in the magneto-dielectric response.Comment: 19 pages, 6 figure
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