Quantifying excitations of quasinormal mode systems

Computations of the strong field generation of gravitational waves by black hole processes produce waveforms that are dominated by quasinormal (QN) ringing, a damped oscillation characteristic of the black hole. We describe here the mathematical problem of quantifying the QN content of the waveforms generated. This is done in several steps: (i) We develop the mathematics of QN systems that are complete (in a sense to be defined) and show that there is a quantity, the ``excitation coefficient,'' that appears to have the properties needed to quantify QN content. (ii) We show that incomplete systems can (at least sometimes) be converted to physically equivalent complete systems. Most notably, we give a rigorous proof of completeness for a specific modified model problem. (iii) We evaluate the excitation coefficient for the model problem, and demonstrate that the excitation coefficient is of limited utility. We finish by discussing the general question of quantification of QN excitations, and offer a few speculations about unavoidable differences between normal mode and QN systems.Comment: 27 pages, 14 figures. To be published in: J. Math. Phys. (1999

Large-scale Hierarchical Alignment for Data-driven Text Rewriting

We propose a simple unsupervised method for extracting pseudo-parallel monolingual sentence pairs from comparable corpora representative of two different text styles, such as news articles and scientific papers. Our approach does not require a seed parallel corpus, but instead relies solely on hierarchical search over pre-trained embeddings of documents and sentences. We demonstrate the effectiveness of our method through automatic and extrinsic evaluation on text simplification from the normal to the Simple Wikipedia. We show that pseudo-parallel sentences extracted with our method not only supplement existing parallel data, but can even lead to competitive performance on their own.Comment: RANLP 201

Lamina-specific AMPA receptor dynamics following visual deprivation in vivo.

Regulation of AMPA receptor (AMPAR) expression is central to synaptic plasticity and brain function, but how these changes occur in vivo remains elusive. Here, we developed a method to longitudinally monitor the expression of synaptic AMPARs across multiple cortical layers in awake mice using two-photon imaging. We observed that baseline AMPAR expression in individual spines is highly dynamic with more dynamics in primary visual cortex (V1) layer 2/3 (L2/3) neurons than V1 L5 neurons. Visual deprivation through binocular enucleation induces a synapse-specific and depth-dependent change of synaptic AMPARs in V1 L2/3 neurons, wherein deep synapses are potentiated more than superficial synapses. The increase is specific to L2/3 neurons and absent on apical dendrites of L5 neurons, and is dependent on expression of the AMPAR-binding protein GRIP1. Our study demonstrates that specific neuronal connections, across cortical layers and even within individual neurons, respond uniquely to changes in sensory experience

Selective Laser Sintering of Passive Dynamic Ankle-Foot Orthoses

Passive dynamic ankle-foot orthoses (AFO’s) are used to improve gait performance in those with various neuromuscular disorders. An important design characteristic of passive dynamic AFOs is the storage and release of elastic energy within its structure to help satisfy the energetic demands of walking. Thus, minimizing energy dissipation through internal friction is a fundamental criterion for selecting the appropriate AFO material. This study compared the mechanical damping of a carbon-fiber AFO to three geometrically identical AFO’s fabricated using selective laser sintering with different materials. Mechanical damping characteristics ranked the materials as Nylon 11 (best), followed by DuraformTM PA and DuraformTM GF (worst).Mechanical Engineerin

The Persistence of Population III Star Formation

We present a semi-analytic model of star formation in the early universe, beginning with the first metal-free stars. By employing a completely feedback-limited star formation prescription, stars form at maximum efficiency until the self-consistently calculated feedback processes halt formation. We account for a number of feedback processes including a meta-galactic Lyman-Werner background, supernovae, photoionization, and chemical feedback. Halos are evolved combining mass accretion rates found through abundance matching with our feedback-limited star formation prescription, allowing for a variety of Population III (Pop III) initial mass functions (IMFs). We find that, for a number of models, massive Pop III star formation can continue on until at least $z \sim 20$ and potentially past $z \sim 6$ at rates of around $10^{-4}$ to $10^{-5}$ M$_\odot$ yr$^{-1}$ Mpc$^{-3}$, assuming these stars form in isolation. At this point Lyman-Werner feedback pushes the minimum halo mass for star formation above the atomic cooling threshold, cutting off the formation of massive Pop III stars. We find that, in most models, Pop II and Pop III star formation co-exist over cosmological time-scales, with the total star formation rate density and resulting radiation background strongly dominated by the former before Pop III star formation finally ends. These halos form at most $\sim 10^3$ M$_\odot$ of massive Pop III stars during this phase and typically have absolute magnitudes in the range of $M_\text{AB} = -5$ to $-10$. We also briefly discuss how future observations from telescopes such as JWST or WFIRST and 21-cm experiments may be able to constrain unknown parameters in our model such as the IMF, star formation prescription, or the physics of massive Pop III stars.Comment: 16 pages, 13 figures, submitted to MNRA

Estimating the Impact of California Tribal Gaming on Demand for Casino Gaming in Nevada

Since 1990, the California tribal casino industry has grown from a very small and insignificant industry to one with annual gross gaming revenues of about $7.5 billion per annum by 2009. Over this same period, Nevada\u27s gaming revenues grew from approximately$5.0 billion in 1990 to $10.4 billion in 2009, having declined from a peak of$12.8 billion in 2007. Much of the recent decline in Nevada and especially Las Vegas can be attributed to the severity of the economic recession of 2007-2009. However, the major Northern Nevada destination resorts of Reno and South Lake Tahoe had experienced substantial slowdowns or contraction of their gaming industries since the advent of California tribal gaming in the early 1990s, as measured in a number of ways, including number of gaming devices, employment, and gross gaming revenues adjusted for inflation. Las Vegas, on the other hand, had experienced substantial real growth over this same period, until the Great Recession of 2007-2009, at which point it experienced a dramatic reversal of fortune. This analysis estimates demand relationships for gaming activity in the major tourism markets in Northern and Southern Nevada, by specifying a number of variables that relate to the demand for gambling in these markets as well as noting monthly seasonal shifts. It also examines the competitive links between the expansion of California tribal gaming and the Nevada casino industry\u27s economic performance. Regression analysis is utilized to establish the relationship between the growth and expansion of tribal casinos in California and the expansion or contraction of gaming in Nevada\u27s major regions of Reno, Lake Tahoe, and the Las Vegas Strip

Sports Marketing Ethics in Today\u27s Marketplace

Sports marketing is a fast-growing business endeavor. However, certain aspects of it have drawn criticisms from several corners (e.g., media, government, coaches, and fans). This paper raises a number of ethical questions about various dimensions of sports marketing. Advice for addressing some of the ethical problems that occur is provided. The paper specifically asks if organizations using professional sports associations as a promotional lever for increasing sales can be hurt by a lack of ethics on the part of the leagues, teams, or players. It also implies that sport organizations, regardless of economic benefits derived or strong player unions, have an obligation to create a positive and sustainable ethical climate and deliver an enforceable ethical code

Preliminary Results From the Long-Term Inmate Survey: Focus on Child Abuse Histories

This preliminary report of long-term inmates in Alaska correctional facilities finds that over 80 percent of long-term inmates report having been physically abused as children, over 65 percent report having suffered neglect. Other findings related to the child abuse histories of long-term inmates are also reported.Alaska Department of Correction