2,533 research outputs found
Public Land Withdrawal Policy and the Antiquities Act
After setting forth a brief history of public land withdrawals, this comment analyzes the current statutory public land withdrawal scheme as expressed in the Federal Land Policy and Management Act of 1976 (FLPMA) and identifies the various policies underlying FLPMA. Next, an examination of the Antiquities Act\u27s legislative history, judicial interpretation, and use will show that the intended scope of the Act is quite different from both its actual application by Presidents and its interpretation by courts. Evaluating the Act in light of the land withdrawal policies expressed in FLPMA, this comment will conclude that use of the Antiquities Act is so inconsistent with those policies that the Act should be repealed
EFFECT OF FLUID TEMPERATURE AND VOLUME ON THERMOREGULATION IN THE HEAT
The link between thermoregulation, hydration status, and exercise performance in hot humid environments is controversial. The purpose of this study was to evaluate the effects of volume and temperature of ingested fluid on hydration status, thermoregulation and exercise performance. Recreationally active males (N=11, 24.7±5.9 years; VO2max=58.2±6.0 mL/kg/min) completed two 3-hour intermittent exercise trials in the heat (31o WBGT=35.5°C with 50% humidity). Participants consumed either 1 mL/kg body weight (BW) of room temperature water (35.5°C; ROOM) or 0.5 mL/kg of an ice slurry mixture (~0°C; COLD) every ten minutes throughout the trials in a randomized crossover design. Subjects walked on a motorized treadmill at 40% VO2max for 25-minutes followed by 5-minutes of standing rest after which a 1.6 km time trial was completed as quickly as possible on a non-motorized treadmill (Woodway Curve). After completion of the time trial, participants remained seated for the rest of the 1-hour time period. This series of steady state (SS) and time trial (TT) segments was repeated three times over each 3-hour trial. Core temperature and heart rate were monitored continuously throughout the 3-hour trials and used to calculate physiological strain index (PSI). Nude BW was measured pre and post to calculate sweat loss. Body weight loss was significantly higher for the COLD trial (2.2±0.7 and 3.0±0.8 % for the ROOM and COLD respectively, p\u3c0.05). Total water loss was not different between the trials (1.2±0.2 and 1.2±0.2 L/hr, for the ROOM and COLD, respectively). Time trial performance was not different between treatments (ROOM: 9.7±1.3, 10.8±1.4, 12.8±2.4 min for hours 1, 2, and 3, respectively, and COLD: 10.1±1.6, 11.2±2.0, 12.8±2.6 min for hours 1, 2, and 3, respectively) but was impaired over time. These data suggest that it is not simply the volume, but the temperature of the ingested fluid that aids in thermoregulation
A Metric for Rapidly Spinning Black Holes Suitable for Strong-Field Tests of the No-Hair Theorem
According to the no-hair theorem, astrophysical black holes are uniquely
characterized by their masses and spins and are described by the Kerr metric.
Several parametric deviations from the Kerr metric have been suggested to study
observational signatures in both the electromagnetic and gravitational-wave
spectra that differ from the expected Kerr signals. Due to the no-hair theorem,
however, such spacetimes cannot be regular everywhere outside the event
horizons, if they are solutions to the Einstein field equations; they are often
characterized by naked singularities or closed time-like loops in the regions
of the spacetime that are accessible to an external observer. For observational
tests of the no-hair theorem that involve phenomena in the vicinity of the
circular photon orbit or the innermost stable circular orbit around a black
hole, these pathologies limit the applicability of the metrics only to compact
objects that do not spin rapidly. In this paper, we construct a Kerr-like
metric which depends on a set of free parameters in addition to its mass and
spin and which is regular everywhere outside of the event horizon. We derive
expressions for the energy and angular momentum of a particle on a circular
equatorial orbit around the black hole and compute the locations of the
innermost stable circular orbit and the circular photon orbit. We demonstrate
that these orbits change significantly for even moderate deviations from the
Kerr metric. The properties of our metric make it an ideally suited spacetime
to carry out strong-field tests of the no-hair theorem in the electromagnetic
spectrum using the properties of accretion flows around astrophysical black
holes of arbitrary spin.Comment: 11 pages, 7 figures, accepted for publication in PR
Testing black hole no-hair theorem with OJ287
We examine the ability to test the black hole no-hair theorem at the 10%
level in this decade using the binary black hole in OJ287. In the test we
constrain the value of the dimensionless parameter q that relates the scaled
quadrupole moment and spin of the primary black hole: q2 = -q 2 . At the
present we can say that q = 1 \pm 0.3 (one), in agreement with General
Relativity and the no-hair theorems. We demonstrate that this result can be
improved if more observational data is found in historical plate archives for
the 1959 and 1971 outbursts. We also show that the predicted 2015 and 2019
outbursts will be crucial in improving the accuracy of the test. Space-based
photometry is required in 2019 July due the proximity of OJ287 to the Sun at
the time of the outburst. The best situation would be to carry out the
photometry far from the Earth, from quite a different vantage point, in order
to avoid the influence of the nearby Sun. We have considered in particular the
STEREO space mission which would be ideal if it has a continuation in 2019 or
LORRI on board the New Horizons mission to Pluto.Comment: 14 pages, 14 figure
How do texture and color communicate uncertainty in climate change map displays?
We report on an empirical study with over hundred online participants where we investigatedhow texture and color value, two popular visual variables used to convey uncertainty in maps,are understood by non-domain-experts. Participants intuit denser dot textures to mean greaterattribute certainty; irrespective of whether the dot pattern is labeled certain or uncertain. Withthis additional empirical evidence, we hope to further improve our understanding of how non-domain experts interpret uncertainty information depicted in map displays. This in turn willallow us to more clearly and legibly communicate uncertainty information in climate changemaps, so that these displays can be unmistakably understood by decision-makers and the generalpublic
Evidence of reduced surface electron-phonon scattering in the conduction band of Bi_{2}Se_{3} by non-equilibrium ARPES
The nature of the Dirac quasiparticles in topological insulators calls for a
direct investigation of the electron-phonon scattering at the \emph{surface}.
By comparing time-resolved ARPES measurements of the TI Bi_{2}Se_{3} with
different probing depths we show that the relaxation dynamics of the electronic
temperature of the conduction band is much slower at the surface than in the
bulk. This observation suggests that surface phonons are less effective in
cooling the electron gas in the conduction band.Comment: 5 pages, 3 figure
The momentum and photon energy dependence of the circular dichroic photoemission in the bulk Rashba semiconductors BiTeX (X = I, Br, Cl)
Bulk Rashba systems BiTeX (X = I, Br, Cl) are emerging as important
candidates for developing spintronics devices, because of the coexistence of
spin-split bulk and surface states, along with the ambipolar character of the
surface charge carriers. The need of studying the spin texture of strongly
spin-orbit coupled materials has recently promoted circular dichroic Angular
Resolved Photoelectron Spectroscopy (cd-ARPES) as an indirect tool to measure
the spin and the angular degrees of freedom. Here we report a detailed photon
energy dependent study of the cd-ARPES spectra in BiTeX (X = I, Br and Cl). Our
work reveals a large variation of the magnitude and sign of the dichroism.
Interestingly, we find that the dichroic signal modulates differently for the
three compounds and for the different spin-split states. These findings show a
momentum and photon energy dependence for the cd-ARPES signals in the bulk
Rashba semiconductor BiTeX (X = I, Br, Cl). Finally, the outcome of our
experiment indicates the important relation between the modulation of the
dichroism and the phase differences between the wave-functions involved in the
photoemission process. This phase difference can be due to initial or final
state effects. In the former case the phase difference results in possible
interference effects among the photo-electrons emitted from different atomic
layers and characterized by entangled spin-orbital polarized bands. In the
latter case the phase difference results from the relative phases of the
expansion of the final state in different outgoing partial waves.Comment: 6 pages, 4 figure
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