4,788 research outputs found
Look, the World is Watching How We Treat Migrants! The Making of the Anti-Trafficking Legislation during the Ma Administration
Employing the spiral model, this research analyses how anti-human trafficking legislation was promulgated during the Ma Ying-jeou (Ma Yingjiu) presidency. This research found that the government of Taiwan was just as accountable for the violation of migrants’ human rights as the exploitive placement agencies and abusive employers. This research argues that, given its reliance on the United States for political and security support, Taiwan has made great efforts to improve its human rights records and meet US standards for protecting human rights. The reform was a result of multilevel inputs, including US pressure and collaboration between transnational and domestic advocacy groups. A major contribution of this research is to challenge the belief that human rights protection is intrinsic to democracy. In the same light, this research also cautions against Tai-wan’s subscription to US norms since the reform was achieved at the cost of stereotyping trafficking victimhood, legitimising state surveillance, and further marginalising sex workers
Can neutrino-assisted early dark energy models ameliorate the tension in a natural way?
The idea of neutrino-assisted early dark energy (EDE), where a coupling
between neutrinos and the scalar field that models early dark energy (EDE) is
considered, was introduced with the aim of reducing some of the fine-tuning and
coincidence problems that appear in usual EDE models. In order to be relevant
in ameliorating the tension, the contribution of EDE to the total energy
density () should be around 10\% near the redshift of
matter-radiation equality. We verify under which conditions EDE models can
fulfill these requirements for a model with a quartic self-coupling of the EDE
field and an exponential coupling to neutrinos. We find that in the situation
where the EDE field is frozen initially, the contribution to can
be significant but it is not sensitive to the neutrino-EDE coupling and does
not address the EDE coincidence problem. On the other hand, if the EDE field
starts already dynamical at the minimum of the effective potential, it tracks
this time-dependent minimum that presents a feature triggered by the neutrino
transition from relativistic to nonrelativistic particles. This feature
generates in a natural way at around this transition epoch, that
roughly coincides with the matter-radiation equality redshift. For the set of
parameters that we considered we did not find values that satisfy the
requirements on the background cosmological evolution to mitigate the Hubble
tension in a natural way in this particular EDE model.Comment: 6 pages, 4 figures. New version with more detailed analysi
A new approach to the inverse problem for current mapping in thin-film superconductors
A novel mathematical approach has been developed to complete the inversion of
the Biot-Savart law in one- and two-dimensional cases from measurements of the
perpendicular component of the magnetic field using the well-developed
Magneto-Optical Imaging technique. Our approach, especially in the 2D case, is
provided in great detail to allow a straightforward implementation as opposed
to those found in the literature. Our new approach also refines our previous
results for the 1D case [Johansen et al., Phys. Rev. B 54, 16264 (1996)], and
streamlines the method developed by Jooss et al. [Physica C 299, 215 (1998)]
deemed as the most accurate if compared to that of Roth et al. [J. Appl. Phys.
65, 361 (1989)]. We also verify and streamline the iterative technique, which
was developed following Laviano et al. [Supercond. Sci. Technol. 16, 71 (2002)]
to account for in-plane magnetic fields caused by the bending of the applied
magnetic field due to the demagnetising effect. After testing on
magneto-optical images of a high quality YBa2Cu3O7 superconducting thin film,
we show that the procedure employed is effective
Phase behaviour of additive binary mixtures in the limit of infinite asymmetry
We provide an exact mapping between the density functional of a binary
mixture and that of the effective one-component fluid in the limit of infinite
asymmetry. The fluid of parallel hard cubes is thus mapped onto that of
parallel adhesive hard cubes. Its phase behaviour reveals that demixing of a
very asymmetric mixture can only occur between a solvent-rich fluid and a
permeated large particle solid or between two large particle solids with
different packing fractions. Comparing with hard spheres mixtures we conclude
that the phase behaviour of very asymmetric hard-particle mixtures can be
determined from that of the large component interacting via an adhesive-like
potential.Comment: Full rewriting of the paper (also new title). 4 pages, LaTeX, uses
revtex, multicol, epsfig, and amstex style files, to appear in Phys. Rev. E
(Rapid Comm.
Density Functional for Anisotropic Fluids
We propose a density functional for anisotropic fluids of hard body
particles. It interpolates between the well-established geometrically based
Rosenfeld functional for hard spheres and the Onsager functional for elongated
rods. We test the new approach by calculating the location of the the
nematic-isotropic transition in systems of hard spherocylinders and hard
ellipsoids. The results are compared with existing simulation data. Our
functional predicts the location of the transition much more accurately than
the Onsager functional, and almost as good as the theory by Parsons and Lee. We
argue that it might be suited to study inhomogeneous systems.Comment: To appear in J. Physics: Condensed Matte
Structure Factor and Electronic Structure of Compressed Liquid Rubidium
We have applied the quantal hypernetted-chain equations in combination with
the Rosenfeld bridge-functional to calculate the atomic and the electronic
structure of compressed liquid-rubidium under high pressure (0.2, 2.5, 3.9, and
6.1 GPa); the calculated structure factors are in good agreement with
experimental results measured by Tsuji et al. along the melting curve. We found
that the Rb-pseudoatom remains under these high pressures almost unchanged with
respect to the pseudoatom at room pressure; thus, the effective ion-ion
interaction is practically the same for all pressure-values. We observe that
all structure factors calculated for this pressure-variation coincide almost
into a single curve if wavenumbers are scaled in units of the Wigner-Seitz
radius although no corresponding scaling feature is observed in the
effective ion-ion interaction.This scaling property of the structure factors
signifies that the compression in liquid-rubidium is uniform with increasing
pressure; in absolute Q-values this means that the first peak-position ()
of the structure factor increases proportionally to ( being the
specific volume per ion), as was experimentally observed by Tsuji et al.Comment: 18 pages, 11 figure
Spin-dependent correlation in two-dimensional electron liquids at arbitrary degeneracy and spin-polarization: CHNC approach
We apply the classical mapping technique developed recently by Dharma-wardana
and Perrot for a study of the uniform two-dimensional electron system at
arbitrary degeneracy and spin-polarization. Pair distribution functions,
structure factors, the Helmhotz free energy, and the compressibility are
calculated for a wide range of parameters. It is shown that at low temperatures
T/ T_F <0.1, T_F being the Fermi temperature, our results almost reduce to
those of zero-temperature analyses. In the region T/ T_F >= 1, the finite
temperature effects become considerable at high densities for all
spin-polarizations. We find that, in our approximation without bridge
functions, the finite temperature electron system in two dimensions remains to
be paramagnetic fluid until the Wigner crystallization density. Our results are
compared with those of three-dimensional system and indicated are the
similarities in temperature, spin-polarization, and density dependencies of
many physical properties.Comment: 8 pages, 9 figure
Quantum Fluctuations of a Coulomb potential
Long-range properties of the two-point correlation function of the
electromagnetic field produced by an elementary particle are investigated.
Using the Schwinger-Keldysh formalism it is shown that this function is finite
in the coincidence limit outside the region of particle localization. In this
limit, the leading term in the long-range expansion of the correlation function
is calculated explicitly, and its gauge independence is proved. The leading
contribution turns out to be of zero order in the Planck constant, and the
relative value of the root mean square fluctuation of the Coulomb potential is
found to be 1/\sqrt{2}, confirming the result obtained previously within the
S-matrix approach. It is shown also that in the case of a macroscopic body, the
\hbar^0 part of the correlation function is suppressed by a factor 1/N, where N
is the number of particles in the body. Relation of the obtained results to the
problem of measurability of the electromagnetic field is mentioned.Comment: 15 pages, 2 figure
Depletion potential in hard-sphere mixtures: theory and applications
We present a versatile density functional approach (DFT) for calculating the
depletion potential in general fluid mixtures. In contrast to brute force DFT,
our approach requires only the equilibrium density profile of the small
particles {\em before} the big (test) particle is inserted. For a big particle
near a planar wall or a cylinder or another fixed big particle the relevant
density profiles are functions of a single variable, which avoids the numerical
complications inherent in brute force DFT. We implement our approach for
additive hard-sphere mixtures. By investigating the depletion potential for
high size asymmetries we assess the regime of validity of the well-known
Derjaguin approximation for hard-sphere mixtures and argue that this fails. We
provide an accurate parametrization of the depletion potential in hard-sphere
fluids which should be useful for effective Hamiltonian studies of phase
behavior and colloid structure
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