8,456 research outputs found
Fields and fluids on curved non-relativistic spacetimes
We consider non-relativistic curved geometries and argue that the background
structure should be generalized from that considered in previous works. In this
approach the derivative operator is defined by a Galilean spin connection
valued in the Lie algebra of the Galilean group. This includes the usual spin
connection plus an additional "boost connection" which parameterizes the
freedom in the derivative operator not fixed by torsion or metric
compatibility. As an example we write down the most general theory of
dissipative fluids consistent with the second law in curved non-relativistic
geometries and find significant differences in the allowed transport
coefficients from those found previously. Kubo formulas for all response
coefficients are presented. Our approach also immediately generalizes to
systems with independent mass and charge currents as would arise in
multicomponent fluids. Along the way we also discuss how to write general
locally Galilean invariant non-relativistic actions for multiple particle
species at any order in derivatives. A detailed review of the geometry and its
relation to non-relativistic limits may be found in a companion paper
[arXiv:1503.02682].Comment: Reference added. 44 page
Hall viscosity, spin density, and torsion
We investigate the relationship between Hall viscosity, spin density and
response to geometric torsion. For the most general effective action for
relativistic gapped systems, the presence of non-universal terms implies that
there is no relationship between torsion response and Hall viscosity. We also
consider free relativistic and non-relativistic microscopic actions and again
verify the existence of analogous non-universal couplings. Explicit examples
demonstrate that torsion response is unrelated to both Hall viscosity and spin
density. We also argue that relativistic gapped theories must have vanishing
Hall viscosity in Lorentz invariant vacuums.Comment: 15 pages, 1 figur
Physical stress, mass, and energy for non-relativistic matter
For theories of relativistic matter fields there exist two possible
definitions of the stress-energy tensor, one defined by a variation of the
action with the coframes at fixed connection, and the other at fixed torsion.
These two stress-energy tensors do not necessarily coincide and it is the
latter that corresponds to the Cauchy stress measured in the lab. In this note
we discuss the corresponding issue for non-relativistic matter theories. We
point out that while the physical non-relativistic stress, momentum, and mass
currents are defined by a variation of the action at fixed torsion, the energy
current does not admit such a description and is naturally defined at fixed
connection. Any attempt to define an energy current at fixed torsion results in
an ambiguity which cannot be resolved from the background spacetime data or
conservation laws. We also provide computations of these quantities for some
simple non-relativistic actions.Comment: 31 pages, one appendix. Minor clarifications added and typos fixe
New Estimates of Federal Government Tangible Capital and Net Investment
Government capital formation raises a number of issues important to national economic well-being, yet the U.S., unlike most advanced countries, does not account for capital in its formal budget documents. We estimate depreciation of government capital using a methodology developed by Hulten and Wykoff which is based on used asset price data. We estimate a federal government net nonresidential capital stock of over $800 billion in 1984, more than 20% higher than estimated by the BEA. We also find much larger net federal investment since World War II than the BEA. The behavior of military and civilian structures and equipment is also examined.We analyze the potential importance of these results for measuring the net national savings rate, national wealth, the trend in government capital formation relative to private capital formation, and the relationship between net investment and deficits.
Statistical Models of Reconstructed Phase Spaces for Signal Classification
This paper introduces a novel approach to the analysis and classification of time series signals using statistical models of reconstructed phase spaces. With sufficient dimension, such reconstructed phase spaces are, with probability one, guaranteed to be topologically equivalent to the state dynamics of the generating system, and, therefore, may contain information that is absent in analysis and classification methods rooted in linear assumptions. Parametric and nonparametric distributions are introduced as statistical representations over the multidimensional reconstructed phase space, with classification accomplished through methods such as Bayes maximum likelihood and artificial neural networks (ANNs). The technique is demonstrated on heart arrhythmia classification and speech recognition. This new approach is shown to be a viable and effective alternative to traditional signal classification approaches, particularly for signals with strong nonlinear characteristics
Protocol for a multicentre, prospective cohort study of practice patterns and clinical outcomes associated with emergency department sedation for mechanically ventilated patients: The ED-SED Study
Characterization of the bovine type I IFN locus: rearrangements, expansions, and novel subfamilies
<p>Abstract</p> <p>Background</p> <p>The Type I interferons (IFN) have major roles in the innate immune response to viruses, a function that is believed to have led to expansion in the number and complexity of their genes, although these genes have remained confined to single chromosomal region in all mammals so far examined. <it>IFNB </it>and <it>IFNE </it>define the limits of the locus, with all other Type I IFN genes except <it>IFNK </it>distributed between these boundaries, strongly suggesting that the locus has broadened as IFN genes duplicated and then evolved into a series of distinct families.</p> <p>Results</p> <p>The Type I IFN locus in <it>Bos taurus </it>has undergone significant rearrangement and expansion compared to mouse and human, however, with the constituent genes separated into two sub-loci separated by >700 kb. The <it>IFNW </it>family is greatly expanded, comprising 24 potentially functional genes and at least 8 pseudogenes. The <it>IFNB </it>(n = 6), represented in human and mouse by one copy, are also present as multiple copies in <it>Bos taurus</it>. The <it>IFNT</it>, which encode a non-virally inducible, ruminant-specific IFN secreted by the pre-implantation conceptus, are represented by three genes and two pseudogenes. The latter have sequences intermediate between <it>IFNT </it>and <it>IFNW</it>. A new Type I IFN family (<it>IFNX</it>) of four members, one of which is a pseudogene, appears to have diverged from the <it>IFNA </it>lineage at least 83 million years ago, but is absent in all other sequenced genomes with the possible exception of the horse, a non-ruminant herbivore.</p> <p>Conclusion</p> <p>In summary, we have provided the first comprehensive annotation of the Type I IFN locus in <it>Bos taurus</it>, thereby providing an insight into the functional evolution of the Type I IFN in ruminants. The diversity and global spread of the ruminant species may have required an expansion of the Type I IFN locus and its constituent genes to provide broad anti-viral protection required for foraging and foregut fermentation.</p
Predicting Postprobationary Job Performance of Police Officers Using CPI and MMPI–2–RF Test Data Obtained During Preemployment Psychological Screening
We examined associations between prehire California Psychological Inventory (CPI) and prorated Minnesota Multiphasic Personality Inventory–2 Restructured Form (MMPI–2–RF) scores (calculated from MMPI profiles) and supervisor ratings for a sample of 143 male police officers. Substantive scale scores in this sample were meaningfully lower than those obtained by the tests’ normative samples in the case of the MMPI–2–RF and meaningfully higher in the case of the CPI (indicating less psychological dysfunction). Test scores from both instruments showed substantial range restriction, consistent with those produced by members of the police candidate comparison groups (Corey & Ben-Porath, 2014Corey, D. M., & Ben-Porath, Y. S. (2014). User\u27s guide for the MMPI-2-RF Police Candidate Interpretive Report. Minneapolis, MN: University of Minnesota Press. [Google Scholar]; Roberts & Johnson, 2001Roberts, M. D., & Johnson, M. (2001). CPI: Police and public safety selection report technical manual. Unpublished manuscript. Retrieved fromhttp://media.post.ca.gov/. [Google Scholar]). After applying a statistical correction for range restriction, we found a number of meaningful associations between both CPI and MMPI–2–RF substantive scale scores and supervisor ratings. For the MMPI–2–RF, findings for scales from the emotional dysfunction and interpersonal functioning domains of the test were particularly strong. For the CPI, findings for scales indicating conformity with social norms, integrity, and tolerance were strong, as were the findings for an index indicating risk of termination. Hierarchical regression analyses showed that MMPI–2–RF and CPI scores complement each other, accounting for incremental variance in the prediction of job-related variables over and above each other. Implications of these findings for assessment science and practice are discussed
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