30 research outputs found
An optimized chiral nucleon-nucleon interaction at next-to-next-to-leading order
We optimize the nucleon-nucleon interaction from chiral effective field
theory at next-to-next- to-leading order. The resulting new chiral force
NNLOopt yields \chi^2 \approx 1 per degree of freedom for laboratory energies
below approximately 125 MeV. In the A = 3, 4 nucleon systems, the contributions
of three-nucleon forces are smaller than for previous parametrizations of
chiral interactions. We use NNLOopt to study properties of key nuclei and
neutron matter, and demonstrate that many aspects of nuclear structure can be
understood in terms of this nucleon-nucleon interaction, without explicitly
invoking three-nucleon forces.Comment: 6 pages, 4 figure
Computational Nuclear Physics and Post Hartree-Fock Methods
We present a computational approach to infinite nuclear matter employing
Hartree-Fock theory, many-body perturbation theory and coupled cluster theory.
These lectures are closely linked with those of chapters 9, 10 and 11 and serve
as input for the correlation functions employed in Monte Carlo calculations in
chapter 9, the in-medium similarity renormalization group theory of dense
fermionic systems of chapter 10 and the Green's function approach in chapter
11. We provide extensive code examples and benchmark calculations, allowing
thereby an eventual reader to start writing her/his own codes. We start with an
object-oriented serial code and end with discussions on strategies for porting
the code to present and planned high-performance computing facilities.Comment: 82 pages, to appear in Lecture Notes in Physics (Springer), "An
advanced course in computational nuclear physics: Bridging the scales from
quarks to neutron stars", M. Hjorth-Jensen, M. P. Lombardo, U. van Kolck,
Editor
Linking morphological and molecular taxonomy for the identification of poultry house, soil, and nest dwelling mites in the Western Palearctic
Because of its ability to expedite specimen identification and species delineation, the barcode index number (BIN) system presents a powerful tool to characterize hyperdiverse invertebrate groups such as the Acari (mites). However, the congruence between BINs and morphologically recognized species has seen limited testing in this taxon. We therefore apply this method towards the development of a barcode reference library for soil, poultry litter, and nest dwelling mites in the Western Palearctic. Through analysis of over 600 specimens, we provide DNA barcode coverage for 35 described species and 70 molecular taxonomic units (BINs). Nearly 80% of the species were accurately identified through this method, but just 60% perfectly matched (1:1) with BINs. High intraspecific divergences were found in 34% of the species examined and likely reflect cryptic diversity, highlighting the need for revision in these taxa. These findings provide a valuable resource for integrative pest management, but also highlight the importance of integrating morphological and molecular methods for fine-scale taxonomic resolution in poorly-known invertebrate lineages
Head repositioning accuracy to neutral: A comparative study of error calculation
Deficits in cervical proprioception have been identified in subjects With neck pain through the Measure of head repositioning accuracy (HRA). Nevertheless there appears to be 110 general Consensus regarding the construct of measurement of error used for calculating HRA. This study investigated four different mathematical methods of measurement of error to determine if there were any differences in their ability to discriminate between a control group and subjects with a whiplash associated disorder