545 research outputs found
Holocene Mollusks of the Knife and Heart Rivers, Southwestern North Dakota
From 12 collecting sites in the Knife River, southwestern North Dakota, at least 15 species of aquatic mollusks were found. From 4 fossil sites on the same river, at least 17 species of aquatic mollusks were found in addition to 11 species of fossil terrestrial gastropods. From 18 collecting sites in the Heart River, southwestern North Dakota, at least 18 species of aquatic mollusks are presently living. From 6 fossil sites on this river, at least 10 species of aquatic mollusks were found in addition to 4 species of fossil terrestrial gastropods. The unionid family was represented in the Knife and Heart River by each having 6 species living presently and 4 species as fossil. The pisidiid family was represented in both rivers by two genera. The Knife River contained 7 species of aquatic gastropods living presently and the Heart River contained 10 species living presently. As aquatic gastropod fossils, however, there were 11 species from the Knife River and 4 species from the Heart River.
Of the unionids, Leptodea laevissima (Lea) occurs alive in the lower reaches of both rivers but does not occur as a fossil. One specimen of Lampsilis ventricosa (Barnes) establishes the existence of this species in the Missouri River drainage presently; this species does occur as fossil. Anodontoides ferussacianus (Lea) was not found in the fossil assemblage of the Heart River.
The living aquatic gastropod faunas of the two rivers are approximately equivalent to the aquatic gastropod fossil fauna. The fossil assemblage of the Heart River did contain Probythinella lacustris (Baker), a species that was not found in the Knife River. The fossil presence of Armiger crista (Linnaeus, Stagnicola caperata (Say), and Lymnaea stagnalis (Linne) indicate that most of the fossil sediments studied were deposited in a pond or slow-water environment.
The fossil terrestrial gastropods do not indicate any different environments than those found presently on the two rivers. The requirements of Oxyloma retusa (Lea), preferring moist conditions, and Discus cronkhitei (Newcomb), preferring woodland conditions, are adequately met.
Therefore, a significant change in the regiman of the rivers is not evident as the total species are essentially the same, living or fossil.
The molluscan faunal fossil finds are post-5,440 years B. P. ± 200 years or late Holocene
Semi-quantitative characterisation of binary salt mixtures with static secondary ion mass spectrometry (S-SIMS)
Static secondary ion mass spectrometry (S-SIMS) for the characterization of surface components in mineral particulates
Dirac versus Reduced Quantization of the Poincar\'{e} Symmetry in Scalar Electrodynamics
The generators of the Poincar\'{e} symmetry of scalar electrodynamics are
quantized in the functional Schr\"{o}dinger representation. We show that the
factor ordering which corresponds to (minimal) Dirac quantization preserves the
Poincar\'{e} algebra, but (minimal) reduced quantization does not. In the
latter, there is a van Hove anomaly in the boost-boost commutator, which we
evaluate explicitly to lowest order in a heat kernel expansion using zeta
function regularization. We illuminate the crucial role played by the gauge
orbit volume element in the analysis. Our results demonstrate that preservation
of extra symmetries at the quantum level is sometimes a useful criterion to
select between inequivalent, but nevertheless self-consistent, quantization
schemes.Comment: 24 page
Diffeomorphisms as Symplectomorphisms in History Phase Space: Bosonic String Model
The structure of the history phase space of a covariant field system
and its history group (in the sense of Isham and Linden) is analyzed on an
example of a bosonic string. The history space includes the time map
from the spacetime manifold (the two-sheet) to a
one-dimensional time manifold as one of its configuration variables. A
canonical history action is posited on such that its restriction to
the configuration history space yields the familiar Polyakov action. The
standard Dirac-ADM action is shown to be identical with the canonical history
action, the only difference being that the underlying action is expressed in
two different coordinate charts on . The canonical history action
encompasses all individual Dirac-ADM actions corresponding to different choices
of foliating . The history Poisson brackets of spacetime fields
on induce the ordinary Poisson brackets of spatial fields in the
instantaneous phase space of the Dirac-ADM formalism. The
canonical history action is manifestly invariant both under spacetime
diffeomorphisms Diff and temporal diffeomorphisms Diff. Both of
these diffeomorphisms are explicitly represented by symplectomorphisms on the
history phase space . The resulting classical history phase space
formalism is offered as a starting point for projection operator quantization
and consistent histories interpretation of the bosonic string model.Comment: 45 pages, no figure
Characterization of radiolytically generated degradation products in the strip section of a TRUEX flowsheet
This report presents a summary of the work performed to meet the FCRD level 2 milestone M3FT-13IN0302053, “Identification of TRUEX Strip Degradation.” The INL radiolysis test loop has been used to identify radiolytically generated degradation products in the strip section of the TRUEX flowsheet. These data were used to evaluate impact of the formation of radiolytic degradation products in the strip section upon the efficacy of the TRUEX flowsheet for the recovery of trivalent actinides and lanthanides from acidic solution. The nominal composition of the TRUEX solvent used in this study is 0.2 M CMPO and 1.4 M TBP dissolved in n-dodecane and the nominal composition of the TRUEX strip solution is 1.5 M lactic acid and 0.050 M diethylenetriaminepentaacetic acid. Gamma irradiation of a mixture of TRUEX process solvent and stripping solution in the test loop does not adversely impact flowsheet performance as measured by stripping americium ratios. The observed increase in americium stripping distribution ratios with increasing absorbed dose indicates the radiolytic production of organic soluble degradation compounds
The Moyal-Lie Theory of Phase Space Quantum Mechanics
A Lie algebraic approach to the unitary transformations in Weyl quantization
is discussed. This approach, being formally equivalent to the
-quantization, is an extension of the classical Poisson-Lie formalism
which can be used as an efficient tool in the quantum phase space
transformation theory.Comment: 15 pages, no figures, to appear in J. Phys. A (2001
Competitive Federalism: A Political-Economy General Equilibrium Approach
This paper develops a modelling framework within which questions of fiscal federalism can be handled. Regional computable general equilibrium (CGE) models form one good approach for examining such questions. However, conventional regional CGE models contain little, if any, theory relating to optimal economic decision-making by governments. In this paper we overcome this limitation by analysing a simple two-region GE model to which maximising behaviour by regional governments is added. We call this a regional political-economy general equilibrium (PEGE) model. We begin by considering a model with only regional governments. We then introduce a rudimentary federal government and consider two cases; in the first the federal government carries out a lump-sum transfer of resources from one regional government to another and in the second it imposes lump-sum income taxes on households and uses this revenue to make transfers to regional governments. We compare the implications of the PEGE model with and without the federal government transfers and conclude that optimising regional governments change their own tax rates to offset the effects on their citizens of the federal government action.
The Efficiency of Federal Inter-Regional Transfers Under a Regime of Politically-Maximizing Regional Governments
The Effects of Federal Inter-Regional Transfers with Optimizing Regional Governments
This paper analyses a simple inter-governmental transfer within a two-regional federal model with optimising regional governments and an exogenous federal government. Regions are linked by inter-regional migration of labour and households migrate from one region to the other in response to inter-regional differences in utility. Regional governments determined their tax and expenditure settings in order to maximise the welfare of the region's representative household. The federal government exists solely to transfer resources from one region to another. The model is solved numerically, after linearlisation and calibration using data for the Australian states. We find that the federal government transfers have only trivial effects on welfare, ie that the welfare effects of the transfer are undone by the migration response of households and the tax and expenditure changes of regional governments. Most of the 'undoing' comes from inter-regional migration.
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