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Authority of State and Local Police to Enforce Federal Immigration Law
[Excerpt] This report discusses the authority of state and local law enforcement to assist in the enforcement of federal immigration law through the investigation and arrest of persons believed to have violated such laws. It describes current provisions in federal law that permit state and local police to enforce immigration law directly, analyzes major cases concerning the ability of states and localities to assist in immigration enforcement, and briefly examines opinions on the issue by the Office of Legal Counsel (OLC) within the Department of Justice. This report does not discuss legal issues raised by states and localities enacting their own immigration-related laws, including measures intended to supplement federal law through the imposition of additional criminal or civil penalties
Global impact of the Antarctic ozone hole: Simulations with a 3-D chemical transport model
A study of the Antarctic ozone hole was made with a 3-D chemical transport model using linearized photochemistry for ozone based on observed distribution. The tracer model uses the winds and convection from the GISS general circulation model (8 deg x 10 deg x 23 layers). A 3-year control run of the ozone distribution is compared with the observed climatology. In two experiments, a hypothetical Antarctic ozone hole is induced on October 1 and on November 1; the tracer model is integrated for 1 year with the standard linearized chemistry. The initial depletion, 90 percent of the O sub 3 poleward of 70 S between 25 and 180 mbar, amounts to about 5 percent of the total O sub 3 in the Southerm Hemisphere. As the vortex breaks down and the hole is dispersed, significant depletions to column ozone, of order 10 D.U., occur as far north as 36 S during Austral summer. One year later, about 25 percent of the original depletion remains, mostly below 100 mbar and poleward of 30 S. Details of the calculations are shown, along with a budget analysis showing the fraction of the hole filled in by photochemistry versus that transported into the troposhere
Observations of the X-ray Nova GRO~J0422+32: II: Optical Spectra Approaching Quiescence
We present results obtained from a series of 5~\AA\ resolution spectra of the
X-ray Nova GRO~J0422+32 obtained in 1993~October, when the system was
approximately 2 magnitudes above quiescence, with . The data
were obtained in an effort to measure the orbital radial velocity curve of the
secondary, but detection of the narrow photospheric absorption lines needed to
do this proved elusive. Instead we found wide absorption bands reminiscent of
M~star photospheric features. The parameters determined by fitting accretion
disk line profiles (Smak profiles) to the H line are similar to those
found in several strong black-hole candidates. Measurements of the velocity of
the H line are consistent with an orbital period of 5.1~hours and a
velocity semi-amplitude of the primary of ~\kms. These measurements,
when combined with measurements of the velocity semi-amplitude of the secondary
made by others, indicate that the mass ratio . If the secondary
follows the empirical mass-radius relation found for CVs, the low implies a
primary mass of \mo, and a rather low (face-on) inclination. The
H EW is found to be modulated on the orbital period with a phasing that
implies a partial eclipse of the disk by the secondary, but simultaneous R~band
photometry shows no evidence for such an eclipse.Comment: Accepted for ApJ, plain latex, 5 figures available as self-extracting
uuendoced, compressed, tarfiles (from uufiles
PEPS as unique ground states of local Hamiltonians
In this paper we consider projected entangled pair states (PEPS) on arbitrary
lattices. We construct local parent Hamiltonians for each PEPS and isolate a
condition under which the state is the unique ground state of the Hamiltonian.
This condition, verified by generic PEPS and examples like the AKLT model, is
an injective relation between the boundary and the bulk of any local region.
While it implies the existence of an energy gap in the 1D case we will show
that in certain cases (e.g., on a 2D hexagonal lattice) the parent Hamiltonian
can be gapless with a critical ground state. To show this we invoke a mapping
between classical and quantum models and prove that in these cases the
injectivity relation between boundary and bulk solely depends on the lattice
geometry.Comment: 8 page
Cosmological Parameters from the Comparison of the 2MASS Gravity Field with Peculiar Velocity Surveys
We compare the peculiar velocity field within 65 Mpc predicted from
2MASS photometry and public redshift data to three independent peculiar
velocity surveys based on type Ia supernovae, surface brightness fluctuations
in ellipticals, and Tully-Fisher distances to spirals. The three peculiar
velocity samples are each in good agreement with the predicted velocities and
produce consistent results for \beta_{K}=\Omega\sbr{m}^{0.6}/b_{K}. Taken
together the best fit . We explore the effects of
morphology on the determination of by splitting the 2MASS sample into
E+S0 and S+Irr density fields and find both samples are equally good tracers of
the underlying dark matter distribution, but that early-types are more
clustered by a relative factor b\sbr{E}/b\sbr{S} \sim 1.6. The density
fluctuations of 2MASS galaxies in Mpc spheres in the local volume is
found to be \sigma\sbr{8,K} = 0.9. From this result and our value of
, we find \sigma_8 (\Omega\sbr{m}/0.3)^{0.6} = 0.91\pm0.12. This
is in excellent agreement with results from the IRAS redshift surveys, as well
as other cosmological probes. Combining the 2MASS and IRAS peculiar velocity
results yields \sigma_8 (\Omega\sbr{m}^/0.3)^{0.6} = 0.85\pm0.05.Comment: 11 pages, ApJ accepte
Entanglement, fractional magnetization and long-range interactions
Based on the theory of Matrix Product States, we give precise statements and
complete analytical proofs of the following claim: a large fractionalization in
the magnetization or the need of long-range interactions imply large
entanglement in the state of a quantum spin chain.Comment: 11 pages, 1 figur
A Two-dimensional Spectral Analysis of Short Period Gravity Waves Imaged in the OI (557.7 nm) and Near Infrared OH Nightglow Emissions Over Arecibo, Puerto Rico
In January 1993 an extensive set of radar and optical data was gathered from various key sites around the world during a coordinated â10 Day Runâ designed to investigate the coupled dynamic behavior of the upper atmosphere on a large, medium and small scale. As part of this campaign an allâsky CCD imaging system was operated at Arecibo Observatory, Puerto Rico, to help quantify the response of the low latitude mesosphereâthermosphere system to short period (\u3c1 hour) gravity waves. Measurements of the OI(557.7 nm) and near infrared OH nightglow emissions were made in conjunction with photometric and ISR radar soundings and revealed an abundance of smallâscale structure in the 80â100 km range. In this letter we apply twoâdimensional spectral analysis techniques to aid in the interpretation of a complex set of image data that consisted of two intersecting quasiâmonochromatic gravity wave patterns progressing on approximately orthogonal headings. An investigation of the spectral content and temporal evolution of these wave motions at each emission altitude is presented
Strings, Projected Entangled Pair States, and variational Monte Carlo methods
We introduce string-bond states, a class of states obtained by placing
strings of operators on a lattice, which encompasses the relevant states in
Quantum Information. For string-bond states, expectation values of local
observables can be computed efficiently using Monte Carlo sampling, making them
suitable for a variational abgorithm which extends DMRG to higher dimensional
and irregular systems. Numerical results demonstrate the applicability of these
states to the simulation of many-body sytems.Comment: 4 pages. v2: Submitted version, containing more numerical data.
Changed title and renamed "string states" to "string-bond states" to comply
with PRL conventions. v3: Accepted version, Journal-Ref. added (title differs
from journal
Gapless Hamiltonians for the toric code using the PEPS formalism
We study Hamiltonians which have Kitaev's toric code as a ground state, and
show how to construct a Hamiltonian which shares the ground space of the toric
code, but which has gapless excitations with a continuous spectrum in the
thermodynamic limit. Our construction is based on the framework of Projected
Entangled Pair States (PEPS), and can be applied to a large class of
two-dimensional systems to obtain gapless "uncle Hamiltonians".Comment: 8 pages, 2 figure
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