3,393 research outputs found
Effects of Mortality Salience on Anti- Atheist Prejudice: A Terror Management Perspective
Terror Management Theory argues that mortality salience is an important motivator in how people behave throughout their lives, and can influence how prejudiced individuals become. In this study we triggered participants’ mortality salience to test this claim, as well as measured the attitudes of prejudice have for atheists compared to homosexuals to see if they differ. Mortality salience did not have an effect on prejudice in this experiment, but anti-atheist prejudice was significantly higher than anti-homosexual prejudice. Although these findings are small, they confirm a need for continued research on prejudice against religious minorities, such as atheists, and how to reduce it
Fluid Elasticity Can Enable Propulsion at Low Reynolds Number
Conventionally, a microscopic particle that performs a reciprocal stroke
cannot move through its environment. This is because at small scales, the
response of simple Newtonian fluids is purely viscous and flows are
time-reversible. We show that by contrast, fluid elasticity enables propulsion
by reciprocal forcing that is otherwise impossible. We present experiments on
rigid objects actuated reciprocally in viscous fluids, demonstrating for the
first time a purely elastic propulsion set by the object's shape and boundary
conditions. We describe two different artificial "swimmers" that experimentally
realize this principle.Comment: 5 pages, 4 figure
Relationships between synoptic-scale transport and interannual variability of inorganic cations in surface snow at Summit, Greenland: 1992-1996
To fully utilize the long-term chemical records retrieved from central Greenland ice cores, specific relationships between atmospheric circulation and the variability of chemical species in the records need to be better understood. This research examines associations between the variability of surface snow inorganic cation chemistry at Summit, Greenland (collected during 1992–1996 summer field seasons) and changes in air mass transport pathways and source regions, as well as variations in aerosol source strength. Transport patterns and source regions are determined through 10-day isentropic backward air mass trajectories during a 1 month (late May to late June) common season over the 5 years. Changes in the extent of exposed continental surfaces in source regions are evaluated to estimate aerosol-associated calcium and magnesium ion source strength, while forest fire activity in the circumpolar north is investigated to estimate aerosol ammonium ion source strength. During the 1995 common season, 3 times more calcium and magnesium accumulated in the snowpack than the other study years. Also, an increasing trend of ammonium concentration was noted throughout the 5 years. Anomalous transport pathways and velocities were observed during 1995, which likely contributed to the high levels of calcium and magnesium. Increased forest fire activity in North America was concurrent with increased levels of ammonium and potassium, except for 1996, when ion levels were above average and forest fire activity was below average. Because of the ubiquitous nature of soluble ions, we conclude that it is very difficult to establish a quantitative link between the ion content of snow and firn at Summit and changes in aerosol source regions and source strength
Frank's constant in the hexatic phase
Using video-microscopy data of a two-dimensional colloidal system the
bond-order correlation function G6 is calculated and used to determine the
temperature-dependence of both the orientational correlation length xi6 in the
isotropic liquid phase and the Frank constant F_A in the hexatic phase. F_A
takes the value 72/pi at the hexatic to isotropic liquid phase transition and
diverges at the hexatic to crystal transition as predicted by the KTHNY-theory.
This is a quantitative test of the mechanism of breaking the orientational
symmetry by disclination unbinding
Fluid-Induced Propulsion of Rigid Particles in Wormlike Micellar Solutions
In the absence of inertia, a reciprocal swimmer achieves no net motion in a
viscous Newtonian fluid. Here, we investigate the ability of a reciprocally
actuated particle to translate through a complex fluid that possesses a network
using tracking methods and birefringence imaging. A geometrically polar
particle, a rod with a bead on one end, is reciprocally rotated using magnetic
fields. The particle is immersed in a wormlike micellar (WLM) solution that is
known to be susceptible to the formation of shear bands and other localized
structures due to shear-induced remodeling of its microstructure. Results show
that the nonlinearities present in this WLM solution break time-reversal
symmetry under certain conditions, and enable propulsion of an artificial
"swimmer." We find three regimes dependent on the Deborah number (De): net
motion towards the bead-end of the particle at low De, net motion towards the
rod-end of the particle at intermediate De, and no appreciable propulsion at
high De. At low De, where the particle time-scale is longer then the fluid
relaxation time, we believe that propulsion is caused by an imbalance in the
fluid first normal stress differences between the two ends of the particle
(bead and rod). At De~1, however, we observe the emergence of a region of
network anisotropy near the rod using birefringence imaging. This anisotropy
suggests alignment of the micellar network, which is "locked in" due to the
shorter time-scale of the particle relative to the fluid
Exploratory topic modeling with distributional semantics
As we continue to collect and store textual data in a multitude of domains,
we are regularly confronted with material whose largely unknown thematic
structure we want to uncover. With unsupervised, exploratory analysis, no prior
knowledge about the content is required and highly open-ended tasks can be
supported. In the past few years, probabilistic topic modeling has emerged as a
popular approach to this problem. Nevertheless, the representation of the
latent topics as aggregations of semi-coherent terms limits their
interpretability and level of detail.
This paper presents an alternative approach to topic modeling that maps
topics as a network for exploration, based on distributional semantics using
learned word vectors. From the granular level of terms and their semantic
similarity relations global topic structures emerge as clustered regions and
gradients of concepts. Moreover, the paper discusses the visual interactive
representation of the topic map, which plays an important role in supporting
its exploration.Comment: Conference: The Fourteenth International Symposium on Intelligent
Data Analysis (IDA 2015
Extragalactic megahertz-peaked spectrum radio sources at milliarcsecond scales
Extragalactic peaked-spectrum radio sources are thought to be the progenitors
of larger, radio-loud active galactic nuclei (AGN). Synchrotron self-absorption
(SSA) has often been identified as the cause of their spectral peak. The
identification of new megahertz-peaked spectrum sources from the GaLactic and
Extragalactic All-sky Murchison Widefield Array (GLEAM) survey provides an
opportunity to test how radio sources with spectral peaks below 1 GHz fit
within this evolutionary picture. We observed six peaked-spectrum sources
selected from the GLEAM survey, three that have spectral characteristics which
violate SSA and three that have spectral peaks below 230 MHz, with the Very
Long Baseline Array at 1.55 and 4.96 GHz. We present milliarcsecond resolution
images of each source and constrain their morphology, linear size, luminosity,
and magnetic field strength. Of the sources that are resolved by our study, the
sources that violate SSA appear to be compact doubles, while the sources with
peak frequencies below 230 MHz have core-jet features. We find that all of our
sources are smaller than expected from SSA by factors of >20. We also find that
component magnetic field strengths calculated from SSA are likely inaccurate,
differing by factors of >5 from equipartition estimates. The calculated
equipartition magnetic field strengths more closely resemble estimates from
previously studied gigahertz-peaked spectrum sources. Exploring a model of the
interaction between jets and the interstellar medium, we demonstrate that
free-free absorption (FFA) can accurately describe the linear sizes and peak
frequencies of our sources. Our findings support the theory that there is a
fraction of peaked-spectrum sources whose spectral peaks are best modelled by
FFA, implying our understanding of the early stages of radio AGN is incomplete.Comment: Accepted for publication in Astronomy & Astrophysics (A&A) on 16 July
2019. 13 pages, 6 figure
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