10,396 research outputs found
Casino Atmospherics from a Customer\u27s Perspective: A Re-Examination
Considerable research in recent years has examined the influence of physical evidence, or atmosphere, in a variety of service settings, including leisure services. Not fully covered has been the area of atmosphere in a casino gaming setting. This extension of a previous study further investigates atmospherics in casinos. The findings showed that customers defined casino atmosphere in five key elements: theme, floor layout, ceiling height, employee uniforms, and noise level. Three of the five contributed positively to a player\u27s satisfaction with the gaming experience as shown by the regression analysis. This reinforces previous indications of the need for casino management to create an inviting atmosphere that will maximize customer satisfaction, with specific attention to those aspects that players appear to value most highly
A Customer-based Assessment of Casino Atmospherics
This study investigates the elements of casino atmospherics from the perspective of slot machine players in a Las Vegas Strip casino. Guest responses to a survey instrument that was developed to measure the elements of casino atmosphere were collected and quantitatively analyzed. The results of this study suggest that the design elements of floor layout and theme may be most closely aligned with the concept of casino atmosphere from the perspective of a slot player. This outcome supports the gaming industry\u27s long-standing emphasis on these two areas of casino design. The study also provides further insight about physical evidence in services using a casino setting
Different Scopes for Different Folks: Contrasting outreach approaches to graduate programs and students
Academic libraries are increasingly adding positions that focus on graduate programs and students. What does graduate student outreach look like, and how does it differ from established outreach efforts to undergraduate students? This panel will explore examples from multiple libraries that consider both discipline-specific liaison services and college-wide outreach that requires a more generalist approach. In addition to examples of different outreach efforts, panelists and attendees will discuss successes, challenges, and ways to adapt graduate outreach opportunities at their own institutions
Technical Note: Enhancing Soft Tissue Contrast And Radiation‐Induced Image Changes With Dual‐Energy CT For Radiation Therapy
Purpose
The purpose of this work is to investigate the use of low‐energy monoenergetic decompositions obtained from dual‐energy CT (DECT) to enhance image contrast and the detection of radiation‐induced changes of CT textures in pancreatic cancer. Methods
The DECT data acquired for 10 consecutive pancreatic cancer patients during routine nongated CT‐guided radiation therapy (RT) using an in‐room CT (Definition AS Open, Siemens Healthcare, Malvern, PA) were analyzed. With a sequential DE protocol, the scanner rapidly performs two helical acquisitions, the first at a tube voltage of 80 kVp and the second at a tube voltage of 140 kVp. Virtual monoenergetic images across a range of energies from 40 to 140 keV were reconstructed using an image‐based material decomposition. Intravenous (IV) bolus‐free contrast enhancement in pancreas patient tumors was measured across a spectrum of monoenergies. For treatment response assessment, the changes in CT histogram features (including mean CT number (MCTN), entropy, kurtosis) in pancreas tumors were measured during treatment. The results from the monoenergetic decompositions were compared to those obtained from the standard 120 kVp CT protocol for the same subjects. Results
Data of monoenergetic decompositions of the 10 patients confirmed the expected enhancement of soft tissue contrast as the energy is decreased. The changes in the selected CT histogram features in the pancreas during RT delivery were amplified with the low‐energy monoenergetic decompositions, as compared to the changes measured from the 120 kVp CTs. For the patients studied, the average reduction in the MCTN in pancreas from the first to the last (the 28th) treatment fraction was 4.09 HU for the standard 120 kVp and 11.15 HU for the 40 keV monoenergetic decomposition. Conclusions
Low‐energy monoenergetic decompositions from DECT substantially increase soft tissue contrast and increase the magnitude of radiation‐induced changes in CT histogram textures during RT delivery for pancreatic cancer. Therefore, quantitative DECT may assist the detection of early RT response
Using bacterial biomarkers to identify early indicators of cystic fibrosis pulmonary exacerbation onset
Acute periods of pulmonary exacerbation are the single most important cause of morbidity in cystic fibrosis patients, and may be associated with a loss of lung function. Intervening prior to the onset of a substantially increased inflammatory response may limit the associated damage to the airways. While a number of biomarker assays based on inflammatory markers have been developed, providing useful and important measures of disease during these periods, such factors are typically only elevated once the process of exacerbation has been initiated. Identifying biomarkers that can predict the onset of pulmonary exacerbation at an early stage would provide an opportunity to intervene before the establishment of a substantial immune response, with major implications for the advancement of cystic fibrosis care. The precise triggers of pulmonary exacerbation remain to be determined; however, the majority of models relate to the activity of microbes present in the patient's lower airways of cystic fibrosis. Advances in diagnostic microbiology now allow for the examination of these complex systems at a level likely to identify factors on which biomarker assays can be based. In this article, we discuss key considerations in the design and testing of assays that could predict pulmonary exacerbations
Numerical determination of the material properties of porous dust cakes
The formation of planetesimals requires the growth of dust particles through
collisions. Micron-sized particles must grow by many orders of magnitude in
mass. In order to understand and model the processes during this growth, the
mechanical properties, and the interaction cross sections of aggregates with
surrounding gas must be well understood. Recent advances in experimental
(laboratory) studies now provide the background for pushing numerical aggregate
models onto a new level. We present the calibration of a previously tested
model of aggregate dynamics. We use plastic deformation of surface asperities
as the physical model to bring critical velocities for sticking into accordance
with experimental results. The modified code is then used to compute
compression strength and the velocity of sound in the aggregate at different
densities. We compare these predictions with experimental results and conclude
that the new code is capable of studying the properties of small aggregates.Comment: Accepted for publication in A&
Urban Evolution: The Role of Water
The structure, function, and services of urban ecosystems evolve over time scales from seconds to centuries as Earth’s population grows, infrastructure ages, and sociopolitical values alter them. In order to systematically study changes over time, the concept of “urban evolution” was proposed. It allows urban planning, management, and restoration to move beyond reactive management to predictive management based on past observations of consistent patterns. Here, we define and review a glossary of core concepts for studying urban evolution, which includes the mechanisms of urban selective pressure and urban adaptation. Urban selective pressure is an environmental or societal driver contributing to urban adaptation. Urban adaptation is thesequential process by which an urban structure, function, or services becomes more fitted to its changing environment or human choices. The role of water is vital to driving urban evolution as demonstrated by historical changes in drainage, sewage flows, hydrologic pulses, and long-term chemistry. In the current paper, we show how hydrologic traits evolve across successive generations of urban ecosystems via shifts in selective pressures and adaptations over time. We explore multiple empirical examples including evolving: (1) urban drainage from stream burial to stormwater management; (2) sewage flows and water quality in response to wastewater treatment; (3) amplification of hydrologic pulses due to the interaction between urbanization and climate variability; and (4) salinization and alkalinization of fresh water due to human inputs and accelerated weathering. Finally, we propose a new conceptual model for the evolution of urban waters from the Industrial Revolution to the present day based on empirical trends and historical information. Ultimately, we propose that water itself is a critical driver of urban evolution that forces urban adaptation, which transforms the structure, function, and services of urban landscapes, waterways, and civilizations over time
Giant Planet Formation by Disk Instability: A Comparison Simulation With An Improved Radiative Scheme
There has been disagreement currently about whether cooling in protoplanetary
disks can be sufficiently fast to induce the formation of gas giant
protoplanets via gravitational instabilities. Simulations by our own group and
others indicate that this method of planet formation does not work for disks
around young, low- mass stars inside several tens of AU, while simulations by
other groups show fragmentation into protoplanetary clumps in this region. To
allow direct comparison in hopes of isolating the cause of the differences, we
here present a high resolution three-dimensional hydrodynamics simulation of a
protoplanetary disk, where the disk model, initial perturbation, and simulation
conditions are essentially identical to those used in a set of simulations by
Boss. As in earlier papers by the same author, Boss (2007, hereafter B07)
purports to show that cooling is fast enough to produce protoplanetary clumps.
Here, we evolve the same B07 disk using an improved version of one of our own
radiative schemes and find that the disk does not fragment in our code but
instead quickly settles into a state with only low amplitude nonaxisymmetric
structure, which persists for at least several outer disk rotations. We see no
rapid radiative or convective cooling. We conclude that the differences in
results are due to different treatments of regions at and above the disk
photosphere, and we explain at least one way in which the scheme in B07 may
lead to artificially fast cooling.Comment: accepted by ApJ Letter
The membrane bound N-terminal domain of human adenosine diphosphate ribosylation factor-1 (ARF1)
The small G protein adenosine diphosphate ribosylation factor-1 (ARF1) is activated by cell membrane binding of a self-folding N-terminal domain. We present a model of the human ARF1 N-terminal peptide in planar lipid bilayers, determined from neutron lamellar diffraction and circular dichroism data with molecular modelling. This amphipathic domain lies at a shallow membrane depth, ideal for regulation of the ARF1 bio-timer by rapid, reversible membrane binding. The helical region does not elongate upon membrane binding, leaving the connecting flexible linker region's length unchanged.NRC publication: N
On The Possibility of Enrichment and Differentiation in Gas Giants During Birth by Disk Instability
We investigate the coupling between rock-size solids and gas during the
formation of gas giant planets by disk fragmentation in the outer regions of
massive disks. In this study, we use three-dimensional radiative hydrodynamics
simulations and model solids as a spatial distribution of particles. We assume
that half of the total solid fraction is in small grains and half in large
solids. The former are perfectly entrained with the gas and set the opacity in
the disk, while the latter are allowed to respond to gas drag forces, with the
back reaction on the gas taken into account. To explore the maximum effects of
gas-solid interactions, we first consider 10cm-size particles. We then compare
these results to a simulation with 1 km-size particles, which explores the
low-drag regime. We show that (1) disk instability planets have the potential
to form large cores due to aerodynamic capturing of rock-size solids in spiral
arms before fragmentation; (2) that temporary clumps can concentrate tens of
of solids in very localized regions before clump disruption; (3)
that the formation of permanent clumps, even in the outer disk, is dependent on
the grain-size distribution, i.e., the opacity; (4) that nonaxisymmetric
structure in the disk can create disk regions that have a solids-to-gas ratio
greater than unity; (5) that the solid distribution may affect the
fragmentation process; (6) that proto-gas giants and proto-brown dwarfs can
start as differentiated objects prior to the H collapse phase; (7) that
spiral arms in a gravitationally unstable disk are able to stop the inward
drift of rock-size solids, even redistributing them to larger radii; and, (8)
that large solids can form spiral arms that are offset from the gaseous spiral
arms. We conclude that planet embryo formation can be strongly affected by the
growth of solids during the earliest stages of disk accretion.Comment: Accepted by ApJ. 55 pages including 24 figures. In response to
comments from the referee, we have included a new simulation with km-size
objects and have revised some discussions and interpretations. Major
conclusions remain unchanged, and new conclusions have been added in response
to the new ru
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