7,362 research outputs found
Characterizing Human Mobility Patterns in a Large Street Network
Previous studies demonstrated empirically that human mobility exhibits Levy
flight behaviour. However, our knowledge of the mechanisms governing this Levy
flight behaviour remains limited. Here we analyze over 72 000 people's moving
trajectories, obtained from 50 taxicabs during a six-month period in a large
street network, and illustrate that the human mobility pattern, or the Levy
flight behaviour, is mainly attributed to the underlying street network. In
other words, the goal-directed nature of human movement has little effect on
the overall traffic distribution. We further simulate the mobility of a large
number of random walkers, and find that (1) the simulated random walkers can
reproduce the same human mobility pattern, and (2) the simulated mobility rate
of the random walkers correlates pretty well (an R square up to 0.87) with the
observed human mobility rate.Comment: 13 figures, 17 page
Shocks and a Giant Planet in the Disk Orbiting BP Piscium?
Spitzer IRS spectroscopy supports the interpretation that BP Piscium, a gas
and dust enshrouded star residing at high Galactic latitude, is a first-ascent
giant rather than a classical T Tauri star. Our analysis suggests that BP
Piscium's spectral energy distribution can be modeled as a disk with a gap that
is opened by a giant planet. Modeling the rich mid-infrared emission line
spectrum indicates that the solid-state emitting grains orbiting BP Piscium are
primarily composed of ~75 K crystalline, magnesium-rich olivine; ~75 K
crystalline, magnesium-rich pyroxene; ~200 K amorphous, magnesium-rich
pyroxene; and ~200 K annealed silica ('cristobalite'). These dust grains are
all sub-micron sized. The giant planet and gap model also naturally explains
the location and mineralogy of the small dust grains in the disk. Disk shocks
that result from disk-planet interaction generate the highly crystalline dust
which is subsequently blown out of the disk mid-plane and into the disk
atmosphere.Comment: 25 pages, 4 figures, 1 table. Accepted to Ap
Warm dust in the terrestrial planet zone of a sun-like Pleiad: collisions between planetary embryos?
Only a few solar-type main sequence stars are known to be orbited by warm
dust particles; the most extreme is the G0 field star BD+20 307 that emits ~4%
of its energy at mid-infrared wavelengths. We report the identification of a
similarly dusty star HD 23514, an F6-type member of the Pleiades cluster. A
strong mid-IR silicate emission feature indicates the presence of small warm
dust particles, but with the primary flux density peak at the non-standard
wavelength of ~9 micron. The existence of so much dust within an AU or so of
these stars is not easily accounted for given the very brief lifetime in orbit
of small particles. The apparent absence of very hot (>~1000 K) dust at both
stars suggests the possible presence of a planet closer to the stars than the
dust. The observed frequency of the BD+20 307/HD 23514 phenomenon indicates
that the mass equivalent of Earth's Moon must be converted, via collisions of
massive bodies, to tiny dust particles that find their way to the terrestrial
planet zone during the first few hundred million years of the life of many
(most?) sun-like stars. Identification of these two dusty systems among
youthful nearby solar-type stars suggests that terrestrial planet formation is
common.Comment: ApJ in press, 19 pages including 3 figures and 2 tables, minor
changes to the tables and figure
A patient preference study that evaluated fluticasone furoate and mometasone furoate nasal sprays for allergic rhinitis
Background: Corticosteroid nasal sprays are the mainstay of treatment for allergic rhinitis. These sprays have sensory attributes such as scent and/or odor, taste and aftertaste, and run down the throat and/or the nose, which, when unpleasant, can affect patient preference for, and compliance with, treatment.
Objective: This study examined patient preference for fluticasone furoate nasal spray (FFNS) or mometasone furoate nasal spray (MFNS) based on their sensory attributes after administration in patients with allergic rhinitis.
Methods: This was a multicenter, randomized, double-blind, cross-over study. Patient preferences were determined by using three questionnaires (Overall Preference, Immediate Attributes, and Delayed Attributes).
Results: Overall, 56% of patients stated a preference for FFNS versus 32% for MFNS (p _ 0.001); the remaining 12% stated no preference. More patients stated a preference for FFNS versus MFNS for the attributes of “less drip down the throat” (p _ 0.001), “less run out of the nose” (p _ 0.05), “more soothing” (p _ 0.05), and “less irritating” (p _ 0.001). More patients responded in favor of FFNS versus MFNS for the immediate attributes, “run down the throat” (p _ 0.001), and “run out of the nose” (p _ 0.001), and, in the delayed attributes, “run down the throat” (p _ 0.001), “run out of the nose” (p _ 0.01), “presence of aftertaste” (p _ 0.01), and “no nasal irritation” (p _ 0.001).
Conclusion: Patients with allergic rhinitis preferred FFNS versus MFNS overall and based on a number of individual attributes, including “less drip down the throat,” “less run out of the nose,” and “less irritating.” Greater preference may improve patient adherence and thereby improve symptom management of the patient’s allergic rhinitis
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