5,683 research outputs found
Reconfigurable ferromagnetic liquid droplets.
Solid ferromagnetic materials are rigid in shape and cannot be reconfigured. Ferrofluids, although reconfigurable, are paramagnetic at room temperature and lose their magnetization when the applied magnetic field is removed. Here, we show a reversible paramagnetic-to-ferromagnetic transformation of ferrofluid droplets by the jamming of a monolayer of magnetic nanoparticles assembled at the water-oil interface. These ferromagnetic liquid droplets exhibit a finite coercivity and remanent magnetization. They can be easily reconfigured into different shapes while preserving the magnetic properties of solid ferromagnets with classic north-south dipole interactions. Their translational and rotational motions can be actuated remotely and precisely by an external magnetic field, inspiring studies on active matter, energy-dissipative assemblies, and programmable liquid constructs
Reduced-symmetry two-dimensional solitons in photonic lattices
We demonstrate theoretically and experimentally a novel type of localized
beams supported by the combined effects of total internal and Bragg reflection
in nonlinear two-dimensional square periodic structures. Such localized states
exhibit strong anisotropy in their mobility properties, being highly mobile in
one direction and trapped in the other, making them promising candidates for
optical routing in nonlinear lattices.Comment: 5 pages, 4 figure
Testing the limits of tolerance: How inter-group anxiety amplifies negative and offensive responses to out-group-initiated contact
Three studies examine the amplifying effects of intergroup anxiety on individuals ’ negative and offensive responses to out-group-initiated contact. Because intergroup anxiety typically results in avoidance of the initiation of intergroup contact, we explored how intergroup anxiety affected individuals ’ interpretation of and responses to out-group-initiated contact. We hypothesized that intergroup anxiety amplifies individuals ’ threat appraisal of out-group-initiated contact as well as their feelings of anger and offensive action tendencies toward the out-group. Results showed consistent support for these hypotheses by demonstrating that intergroup anxiety amplified individuals ’ threat appraisal (Studies 2 and 3), anger (Studies 1-3), and offensive action tendencies toward the out-group (Study 2). Anger consistently predicte
The Replication Argument for Incompatibilism
In this paper, I articulate an argument for incompatibilism about moral responsibility and determinism. My argument comes in the form of an extended story, modeled loosely on Peter van Inwagen’s “rollback argument” scenario. I thus call it “the replication argument.” As I aim to bring out, though the argument is inspired by so-called “manipulation” and “original design” arguments, the argument is not a version of either such argument—and plausibly has advantages over both. The result, I believe, is a more convincing incompatibilist argument than those we have considered previously
The Ultimate Fate of Supercooled Liquids
In recent years it has become widely accepted that a dynamical length scale
{\xi}_{\alpha} plays an important role in supercooled liquids near the glass
transition. We examine the implications of the interplay between the growing
{\xi}_{\alpha} and the size of the crystal nucleus, {\xi}_M, which shrinks on
cooling. We argue that at low temperatures where {\xi}_{\alpha} > {\xi}_M a new
crystallization mechanism emerges enabling rapid development of a large scale
web of sparsely connected crystallinity. Though we predict this web percolates
the system at too low a temperature to be easily seen in the laboratory, there
are noticeable residual effects near the glass transition that can account for
several previously observed unexplained phenomena of deeply supercooled liquids
including Fischer clusters, and anomalous crystal growth near T_g
A novel class of CoA-transferase involved in short-chain fatty acid metabolism in butyrate-producing human colonic bacteria
Peer reviewedPublisher PD
New early Eocene tapiromorph perissodactyls from the Ghazij Formation of Pakistan, with implications for mammalian biochronology in Asia
Early Eocene mammals from Indo-Pakistan have only recently come under study. Here we describe the first tapiromorph perissodactyls from the subcontinent. Gandheralophus minor n. gen. and n. sp. and G. robustus n. sp. are two species of Isectolophidae differing in size and in reduction of the anterior dentition. Gandheralophus is probably derived from a primitive isectolophid such as Orientolophus hengdongensis from the earliest Eocene of China, and may be part of a South Asian lineage that also contains Karagalax from the middle Eocene of Pakistan. Two specimens are referred to a new, unnamed species of Lophialetidae. Finally, a highly diagnostic M3 and a molar fragment are described as the new eomoropid chalicothere Litolophus ghazijensis sp. nov. The perissodactyls described here, in contrast to most other mammalian groups published from the early Eocene of Indo-Pakistan, are most closely related to forms known from East and Central Asia. Tapiromorpha are diverse and biochronologically important in the Eocene there and our results allow the first biochronological correlation between early Eocene mammal faunas in Indo-Pakistan and the rest of Asia. We suggest that the upper Ghazij Formation of Pakistan is best correlated with the middle or late part of the Bumbanian Asian Land-Mammal Age, while the Kuldana and Subathu Formations of Pakistan and India are best correlated with the Arshantan Asian Land-Mammal Age
New limb-darkening coefficients and synthetic photometry for model-atmosphere grids at Galactic, LMC, and SMC abundances
New grids of Atlas9 models have been calculated using revised convection
parameters and updated opacity-distribution functions, for chemical
compositions intended to be representative of solar, [M/H] = +0.3, +0.5, Large
Magellanic Cloud (LMC), and Small Magellanic Cloud (SMC) abundances. The grids
cover T(eff) = 3.5-50kK, from log(g) = 5.0 to the effective Eddington limit.
Limb-darkening coefficients and synthetic photometry are presented in the
UBVRIJHKLM, uvby, ugriz, WFCAM, Hipparcos/Tycho, and Kepler passbands for these
models, and for Castelli's comparable `new-ODF' grids. Flux distributions are
given for the new models. The sensitivity of limb-darkening coefficients to the
adopted physics is illustrated
The Lyot Project Direct Imaging Survey of Substellar Companions: Statistical Analysis and Information from Nondetections
The Lyot project used an optimized Lyot coronagraph with Extreme Adaptive
Optics at the 3.63m Advanced Electro-Optical System telescope (AEOS) to observe
86 stars from 2004 to 2007. In this paper we give an overview of the survey
results and a statistical analysis of the observed nondetections around 58 of
our targets to place constraints on the population of substellar companions to
nearby stars. The observations did not detect any companion in the substellar
regime. Since null results can be as important as detections, we analyzed each
observation to determine the characteristics of the companions that can be
ruled out. For this purpose we use a Monte Carlo approach to produce artificial
companions, and determine their detectability by comparison with the
sensitivity curve for each star. All the non-detection results are combined
using a Bayesian approach and we provide upper limits on the population of
giant exoplanets and brown dwarfs for this sample of stars. Our nondetections
confirm the rarity of brown dwarfs around solar-like stars and we constrain the
frequency of massive substellar companions (M>40Mjup) at orbital separation
between and 10 and 50 AU to be <20%.Comment: 32 pages, 11 figures, 2 tables. Published in the Astrophysical
Journa
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