1,382 research outputs found
A revision of the Puer Group of the North American genus Melanoplus, with remarks on the taxonomic value of the concealed male genitalia in the Cyrtacanthacrinae (Orthoptera, Acrididae)
http://deepblue.lib.umich.edu/bitstream/2027.42/56268/1/MP023.pd
A new apterous grouse-locust from western Florida (Orthoptera, Acrididae)
http://deepblue.lib.umich.edu/bitstream/2027.42/56789/1/OP350.pd
The sibling species of the Alutacea Group of the bird-locust genus Schistocerca (Orthoptera, Acrididae, Cyrtacanthacridinae).
http://deepblue.lib.umich.edu/bitstream/2027.42/56360/1/MP116.pd
The systematics and biology of the cave-crickets of the North American tribe Hadenoecini (Orthoptera: Saltatoria: Ensifera: Rhaphidophoridae: Dolichopodinae).
http://deepblue.lib.umich.edu/bitstream/2027.42/56400/1/MP156.pd
The burrowing beetles of the genus Mycotrupes (Coleoptera: Scarabaeidae: Geotrupinae)
http://deepblue.lib.umich.edu/bitstream/2027.42/56329/1/MP084.pd
Spatial Scaling in Model Plant Communities
We present an analytically tractable variant of the voter model that provides
a quantitatively accurate description of beta-diversity (two-point correlation
function) in two tropical forests. The model exhibits novel scaling behavior
that leads to links between ecological measures such as relative species
abundance and the species area relationship.Comment: 10 pages, 3 figure
Coherent and incoherent atomic scattering: Formalism and application to pionium interacting with matter
The experimental determination of the lifetime of pionium provides a very
important test on chiral perturbation theory. This quantity is determined in
the DIRAC experiment at CERN. In the analysis of this experiment, the breakup
probabilities of of pionium in matter are needed to high accuracy as a
theoretical input. We study in detail the influence of the target electrons.
They contribute through screening and incoherent effects. We use Dirac-Hartree-
Fock-Slater wavefunctions in order to determine the corresponding form factors.
We find that the inner-shell electrons contribute less than the weakly bound
outer electrons. Furthermore, we establish a more rigorous estimate for the
magnitude of the contributions form the transverse current (magnetic terms thus
far neglected in the calculations).Comment: Journal of Physics B: Atomic, Molecular and Optical Physics;
(accepted; 22 pages, 6 figures, 26 references) Revised version: more detailed
description of DIRAC experiment; failure of simplest models for incoherent
scattering demonstrated by example
Comparing process-based and constraint-based approaches for modeling macroecological patterns
Ecological patterns arise from the interplay of many different processes, and
yet the emergence of consistent phenomena across a diverse range of ecological
systems suggests that many patterns may in part be determined by statistical or
numerical constraints. Differentiating the extent to which patterns in a given
system are determined statistically, and where it requires explicit ecological
processes, has been difficult. We tackled this challenge by directly comparing
models from a constraint-based theory, the Maximum Entropy Theory of Ecology
(METE) and models from a process-based theory, the size-structured neutral
theory (SSNT). Models from both theories were capable of characterizing the
distribution of individuals among species and the distribution of body size
among individuals across 76 forest communities. However, the SSNT models
consistently yielded higher overall likelihood, as well as more realistic
characterizations of the relationship between species abundance and average
body size of conspecific individuals. This suggests that the details of the
biological processes contain additional information for understanding community
structure that are not fully captured by the METE constraints in these systems.
Our approach provides a first step towards differentiating between process- and
constraint-based models of ecological systems and a general methodology for
comparing ecological models that make predictions for multiple patterns.Comment: 45 pages, 3 main figures, 3 tables, 2 appendices. arXiv admin note:
text overlap with arXiv:1308.073
Radiative and Auger decay data for modelling nickel K lines
Radiative and Auger decay data have been calculated for modelling the K lines
in ions of the nickel isonuclear sequence, from Ni up to Ni. Level
energies, transition wavelengths, radiative transition probabilities, and
radiative and Auger widths have been determined using Cowan's Hartree--Fock
with Relativistic corrections (HFR) method. Auger widths for the third-row ions
(Ni--Ni) have been computed using single-configuration average
(SCA) compact formulae. Results are compared with data sets computed with the
AUTOSTRUCTURE and MCDF atomic structure codes and with available experimental
and theoretical values, mainly in highly ionized ions and in the solid state.Comment: submitted to ApJS. 42 pages. 12 figure
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