2,285 research outputs found
The Constitutional Exercise of the Federal Police Power: A Functional Approach to Federalism
The Employee Polygraph Protection Act of 19881 (Polygraph Act) prohibits the use of polygraph examinations by private employers actively participating in commerce or producing goods for interstate commerce. Prior to this federal action, forty-one states had addressed the issue of employer use of polygraph examinations. Twelve states and the District of Columbia prohibit employer use of polygraph tests altogether. Of the remaining states, some require licensing of examiners and others regulate the circumstances under which an employer may require polygraph examination of an employee. According to the legislative history, federal legislation is necessary because state regulations are ineffective: existing state statutes are not enforced and employers circumvent state laws by pressuring employees into volunteering for the tests or by administering the tests in states without regulations.4 Congress concluded that a uniform national policy was needed to eliminate the use of polygraph examinations in the workplace.\u27The Polygraph Act is justified as an exercise of the power granted to Congress by the interstate commerce clause of the United States Constitution.\u27 Modern commerce clause doctrine has become known as the rational basis test because it permits federal regulation of any activity that Congress reasonably concludes has a substantial effect on interstate commerce.\u27 Since 1937, when the United States Supreme Court began using the rational basis test, only one legislative effort has been held to be beyond the scope of the federal commerce power, and that holding was recently overruled.8 In both theory and practice the interstate commerce clause has evolved into the primary source of federal power over individual conduct...
Part Two reviews the evolution of the commerce power from its origins at the Constitutional Convention through the major cases of this century out of which the modern interpretation has developed. Part Ill addresses the actual threat posed by federal usurpation of state authority by examining the continued value of state governments in an age when technological advances blur state lines and homogenize the population. Part IV proposes to confine the exercise of federal police power to situations in which the commerce clause forbids or compromises state regulation. Part V concludes by suggesting that the Supreme Court must resume its traditional role as protector of individual rights by defining meaningful limits on federal power
Deep Multi-instance Networks with Sparse Label Assignment for Whole Mammogram Classification
Mammogram classification is directly related to computer-aided diagnosis of
breast cancer. Traditional methods rely on regions of interest (ROIs) which
require great efforts to annotate. Inspired by the success of using deep
convolutional features for natural image analysis and multi-instance learning
(MIL) for labeling a set of instances/patches, we propose end-to-end trained
deep multi-instance networks for mass classification based on whole mammogram
without the aforementioned ROIs. We explore three different schemes to
construct deep multi-instance networks for whole mammogram classification.
Experimental results on the INbreast dataset demonstrate the robustness of
proposed networks compared to previous work using segmentation and detection
annotations.Comment: MICCAI 2017 Camera Read
Scaling and energy transfer in rotating turbulence
The inertial-range properties of quasi-stationary hydrodynamic turbulence
under solid-body rotation are studied via high-resolution direct numerical
simulations. For strong rotation the nonlinear energy cascade exhibits
depletion and a pronounced anisotropy with the energy flux proceeding mainly
perpendicularly to the rotation axis. This corresponds to a transition towards
a quasi-two-dimensional flow similar to a linear Taylor-Proudman state. In
contrast to the energy spectrum along the rotation axis which does not scale
self-similarly, the perpendicular spectrum displays an inertial range with
-behavior. A new phenomenology gives a rationale for the
observations. The scaling exponents of structure functions up to
order measured perpendicular to the rotation axis indicate reduced
intermittency with increasing rotation rate. The proposed phenomenology is
consistent with the inferred asymptotic non-intermittent behavior
.Comment: to be published in Europhysics Letters (www.epletters.net), minor
changes to match version in prin
An evaluation of the Goddard Space Flight Center Library
The character and degree of coincidence between the current and future missions, programs, and projects of the Goddard Space Flight Center and the current and future collection, services, and facilities of its library were determined from structured interviews and discussions with various classes of facility personnel. In addition to the tabulation and interpretation of the data from the structured interview survey, five types of statistical analyses were performed to corroborate (or contradict) the survey results and to produce useful information not readily attainable through survey material. Conclusions reached regarding compatability between needs and holdings, services and buildings, library hours of operation, methods of early detection and anticipation of changing holdings requirements, and the impact of near future programs are presented along with a list of statistics needing collection, organization, and interpretation on a continuing or longitudinal basis
The decay of turbulence in rotating flows
We present a parametric space study of the decay of turbulence in rotating
flows combining direct numerical simulations, large eddy simulations, and
phenomenological theory. Several cases are considered: (1) the effect of
varying the characteristic scale of the initial conditions when compared with
the size of the box, to mimic "bounded" and "unbounded" flows; (2) the effect
of helicity (correlation between the velocity and vorticity); (3) the effect of
Rossby and Reynolds numbers; and (4) the effect of anisotropy in the initial
conditions. Initial conditions include the Taylor-Green vortex, the
Arn'old-Beltrami-Childress flow, and random flows with large-scale energy
spectrum proportional to . The decay laws obtained in the simulations for
the energy, helicity, and enstrophy in each case can be explained with
phenomenological arguments that separate the decay of two-dimensional from
three-dimensional modes, and that take into account the role of helicity and
rotation in slowing down the energy decay. The time evolution of the energy
spectrum and development of anisotropies in the simulations are also discussed.
Finally, the effect of rotation and helicity in the skewness and kurtosis of
the flow is considered.Comment: Sections reordered to address comments by referee
Asymptotic theory for a moving droplet driven by a wettability gradient
An asymptotic theory is developed for a moving drop driven by a wettability
gradient. We distinguish the mesoscale where an exact solution is known for the
properly simplified problem. This solution is matched at both -- the advancing
and the receding side -- to respective solutions of the problem on the
microscale. On the microscale the velocity of movement is used as the small
parameter of an asymptotic expansion. Matching gives the droplet shape,
velocity of movement as a function of the imposed wettability gradient and
droplet volume.Comment: 8 fig
Waves attractors in rotating fluids: a paradigm for ill-posed Cauchy problems
In the limit of low viscosity, we show that the amplitude of the modes of
oscillation of a rotating fluid, namely inertial modes, concentrate along an
attractor formed by a periodic orbit of characteristics of the underlying
hyperbolic Poincar\'e equation. The dynamics of characteristics is used to
elaborate a scenario for the asymptotic behaviour of the eigenmodes and
eigenspectrum in the physically relevant r\'egime of very low viscosities which
are out of reach numerically. This problem offers a canonical ill-posed Cauchy
problem which has applications in other fields.Comment: 4 pages, 5 fi
Gravitational radiation from pulsar glitches
The nonaxisymmetric Ekman flow excited inside a neutron star following a
rotational glitch is calculated analytically including stratification and
compressibility. For the largest glitches, the gravitational wave strain
produced by the hydrodynamic mass quadrupole moment approaches the sensitivity
range of advanced long-baseline interferometers. It is shown that the
viscosity, compressibility, and orientation of the star can be inferred in
principle from the width and amplitude ratios of the Fourier peaks (at the spin
frequency and its first harmonic) observed in the gravitational wave spectrum
in the plus and cross polarizations. These transport coefficients constrain the
equation of state of bulk nuclear matter, because they depend sensitively on
the degree of superfluidity.Comment: 28 page
Utility of ambulatory electrocardiographic monitoring for predicting recurrence of sustained ventricular tachyarrhythmias in patients receiving amiodarone
The prognostic implications of changes in ventricular ectopic activity on serial 24 hour ambulatory electrocardiographic (Holter) recordings were prospectively evaluated in 107 patients with a history of sustained ventricular tachyarrhythmias treated with amiodarone for at least 30 days. Twenty-seven patients (25%) had insufficient ventricular ectopic activity < 10 ventricular premature complexes/h and no repetitive forms) on baseline Holter recordings for serial statistical analysis. In 53 (66%) of the remaining 80 patients, serial 24 hour Holter monitor recordings showed efficacy of treatment, defined as a 75% decrease in ventricular premature complexes, a 95% decrease in ventricular couplets and absence of ventricular tachycardia. During a mean followup period of 14.2 ± 9.9 months, 34 (32%) of the 107 patients had recurrence of a sustained ventricular tachyarrhythmia. Holter recording correctly predicted nine recurrences and correctly identified 37 patients who did not experience a recurrence. Holter efficacy failed to predict recurrence of a sustained ventricular tachyarrhythmia in 16 patients, and 18 patients remained free of recurrence despite failure to achieve Holter efficacy. The positive predictive value of Holter monitoring efficacy was 33% and the negative predictive value was 70%; however, these differences were not statistically significant by chi-square analysis. Similar results were obtained using Holter recordings performed relatively early in therapy (6 weeks and 4 months).Of the 27 patients without significant ventricular ectopic activity on the baseline Holter recording, 9 had an arrhythmia recurrence despite continued infrequent ventricular premature complexes and no repetitive forms on subsequent recordings. The recurrence rate in this group (33%) was similar to the overall recurrence rate.Therefore, among patients taking amiodarone for sustained ventricular tachyarrhythmias: 1) 25% will have insufficient ventricular ectopic activity on 24 hour Holter recordings for serial statistical analysis; and 2) in the remaining 75%, data obtained from serial Holter recordings are not predictive of arrhythmia recurrence
A unified hyperbolic formulation for viscous fluids and elastoplastic solids
We discuss a unified flow theory which in a single system of hyperbolic
partial differential equations (PDEs) can describe the two main branches of
continuum mechanics, fluid dynamics, and solid dynamics. The fundamental
difference from the classical continuum models, such as the Navier-Stokes for
example, is that the finite length scale of the continuum particles is not
ignored but kept in the model in order to semi-explicitly describe the essence
of any flows, that is the process of continuum particles rearrangements. To
allow the continuum particle rearrangements, we admit the deformability of
particle which is described by the distortion field. The ability of media to
flow is characterized by the strain dissipation time which is a characteristic
time necessary for a continuum particle to rearrange with one of its
neighboring particles. It is shown that the continuum particle length scale is
intimately connected with the dissipation time. The governing equations are
represented by a system of first order hyperbolic PDEs with source terms
modeling the dissipation due to particle rearrangements. Numerical examples
justifying the reliability of the proposed approach are demonstrated.Comment: 6 figure
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