5,587 research outputs found
Effects of a giant impact on Uranus
The effects of a giant impact on Uranus with respect to the axis tilt of Uranus and its satellites are discussed. The simulations of possible giant impacts were carried out using Cray supercomputers. The technique used is called smooth particle hydrodynamics (SPH). In this technique, the material in the proto-Uranus planet and in the impactor is divided into a large number of particles which can overlap one another so that local averages over these particles determine density and pressure in the problem, and the particles themselves have their own temperatures and internal energies. During the course of the simulation, these particles move around under the influence of the forces acting on them: gravity and pressure gradients. The results of model simulations are presented
Two-photon photochemical long-period grating fabrication in hydrogenated photonic crystal fiber
We report on the photochemical fabrication of a long-period grating in photonic crystal fiber. The characteristic fluence value for inscription is an order of magnitude less than that for standard telecom fiber
Saccade launch site as a predictor of fixation durations in reading: Comments on Hand, Miellet, O’Donnell, and Sereno (2010).
An important question in research on eye movements in reading is whether word frequency and word predictability have additive or interactive effects on fixation durations. A fair number of studies have reported only additive effects of the frequency and predictability of a target word on reading times on that word, failing to show significant interactions. Recently, however, Hand, Miellet, O'Donnell, and Sereno (see record 2010-19099-001) reported interactive effects in a study that included the distance of the prior fixation from the target word (launch site). They reported that when the saccade into the target word was launched from very near to the word (within 3 characters), the predictability effect was larger for low frequency words, but when the saccade was launched from a medium distance (4-6 characters from the word) the predictability effect was larger for high frequency words. Hand et al. argued for the importance of including launch site in analyses of target word fixation durations. Here we describe several problems with Hand et al.'s use of analyses of variance in which launch site is divided into distinct ordinal levels. We describe a more appropriate way to analyze such data-linear mixed-effect models-and we use this method to show that launch site does not modulate the interaction between frequency and predictability in two other data sets
Comparison of Power Dependence of Microwave Surface Resistance of Unpatterned and Patterned YBCO Thin Film
The effect of the patterning process on the nonlinearity of the microwave
surface resistance of YBCO thin films is investigated. With the use of a
sapphire dielectric resonator and a stripline resonator, the microwave of
YBCO thin films was measured before and after the patterning process, as a
function of temperature and the rf peak magnetic field in the film. The
microwave loss was also modeled, assuming a dependence of
on current density . Experimental and modeled results
show that the patterning has no observable effect on the microwave residual
or on the power dependence of .Comment: Submitted to IEEE Trans. MT
From Service to Experience: Understanding and Defining the Hospitality Business
Failure adequately to define or understand hospitality as a commercial phenomenon has created a fragmented academic environment and a schizophrenia in the industry that has the potential to limit its development as a global industry. This article suggests that, by redefining hospitality as behaviour and experience, a new perspective emerges that has exciting implications for the management of hospitality businesses. A framework to describe hospitality in the commercial domain is proposed. This framework suggests a focus on the host–guest relationship, generosity, theatre and performance, ‘lots of little surprises’, and the security of strangers – a focus that provides guests with experiences that are personal, memorable and add value to their lives
Ionic liquid crystals based on 3-perfluoalkyl-1,2,4-triazol-4-ium salts
Liquid-crystalline ionic liquids (LC-ILs) are a class of organic materials that of great current interest: they are defined as organic salts that possess the properties of two interesting kinds of material \u2013 ionic liquids (ILs) and liquid crystals (LCs). LC-ILs combine many interesting features of ILs (e.g. low volatility and the ability to dissolve solutes with a range of polarities) as well as many attractive properties of LCs (e.g. their intrinsic order and anisotropy). This provides unique opportunities that can be exploited in many different fields, for example their use as solvents for extraction processes as well as electrolytes for batteries, fuel cells, and dye-sensitised solar cells1\u20134. These LC-ILs can also be used to immobilise transition-metal catalysts in the liquid phase of biphasic catalytic reactions1 or as reaction media in order to exert control, over the rate, regio- and/or stereochemical outcome of chemical reactions5,6.
We are interested in LC-ILs that are obtained from molecules with small, planar structures based on alkyl and perfluoalkyl-1,2,4-triazol-4-ium salts7\u20139 (Scheme 1). This contribution will report the synthesis, structure and liquid-crystal properties of materials of this type and will discuss preliminary investigations into their physical properties and applications
Unravelling the structure of the C60 and p-But-calix[8]arene complex
Open Access Article. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.The structure of the C60 and p-But-calix[8]arene complex has been reinvestigated, showing an unprecedented continuous layered tetragonal array of fullerenes encapsulated by calixarenes. Electron diffraction data revealed the tetragonal symmetry, with a stepped structure observed by AFM and SEM, and the thickness of the basal plane was measured by XRD, as 2 nm. The molecular simulated arrangement of fullerenes accounts for the ability to take up to ca. 11% of fullerenes C70 in place of the smaller fullerene
Characterization of spotted hyena, Crocuta crocuta microsatellite loci
We have isolated 10 polymorphic microsatellite loci in the spotted hyena,Crocuta crocuta.The loci displayed between eight and 14 alleles in a minimum of 12 individuals tested.
These loci will be used to investigate relatedness within social groups, the genetic structure of populations, sexual selection, and mate choice in spotted hyenas
What are the costs of degraded parafoveal previews during silent reading?
It has been suggested that the preview benefit effect is actually a combination of preview benefit and preview costs. Marx et al. (2015) proposed that visually degrading the parafoveal preview reduces the costs associated with traditional parafoveal letter masks used in the boundary paradigm (Rayner,1975), thus leading to a more neutral baseline. We report two experiments of skilled adults reading silently. In Experiment 1, we found no compelling evidence that degraded previews reduced processing costs associated with traditional letter masks. Moreover, participants were highly sensitive to detecting degraded display changes. Experiment 2 utilized the boundary detection paradigm (Slattery, Angele, & Rayner, 2011) to explore whether participants were capable of detecting actual letter changes or if they were responding purely to changes in degradation. Half of the participants were instructed to respond to any noticed display changes; the other half were instructed to respond only to changes in letter identities. Participants were highly sensitive to degraded changes. In fact, these changes were so apparent that they reduced the sensitivity to letter masks. In the context of the model proposed by Angele, Slattery, and Rayner (2016), we suggest that degraded previews interfere with the attentional stage, as evidenced by the general lack of foveal load effects. In summary, we found that increasingly degrading parafoveal letter masks does not reduce their processing costs in adults, but that both degraded valid and invalid previews introduce additional costs in terms of greater display change awareness
Photoacclimatization by the coral Montastraea cavernosa in the mesophotic zone: light, food, and genetics
Most studies on coral reefs have focused on shallow reef (<30 m) systems due
to the technical limitations of conducting scientific diving deeper than 30 m. Compared to their
shallow-water counterparts, these mesophotic coral reefs (30–150 m) are understudied, which
has slowed our broader understanding of the biodiversity, ecology, and connectivity of
shallow and deep coral reef communities. We know that the light environment is an important
component of the productivity, physiology, and ecology of corals, and it restricts the
distribution of most species of coral to depths of 60 m or less. In the Bahamas, the coral
Montastraea cavernosa has a wide depth distribution, and it is one of the most numerous
corals at mesophotic depths. Using a range of optical, physiological, and biochemical
approaches, the relative dependence on autotrophy vs. heterotrophy was assessed for this
coral from 3 to 91 m. These measurements show that the quantum yield of PSII fluorescence
increases significantly with depth for M. cavernosa while gross primary productivity decreases
with depth. Both morphological and physiological photoacclimatization occurs to a depth of
91 m, and stable isotope data of the host tissues, symbionts, and skeleton reveal a marked
decrease in productivity and a sharp transition to heterotrophy between 45 and 61 m. Below
these depths, significant changes in the genetic composition of the zooxanthellae community,
including genotypes not previously observed, occur and suggest that there is strong selection
for zooxanthellae that are suited for survival in the light-limited environment where
mesophotic M. cavernosa are occurring
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