3,541 research outputs found
Use of domesticated pigs by Mesolithic hunter-gatherers in northwestern Europe
Acknowledgements We thank the Archaeological State Museum Schleswig-Holstein, the Archaeological State Offices of Brandenburg, Lower Saxony and Saxony and the following individuals who provided sample material: Betty Arndt, Jo¨rg Ewersen, Frederick Feulner, Susanne Hanik, Ru¨diger Krause, Jochen Reinhard, Uwe Reuter, Karl-Heinz Ro¨hrig, Maguerita Scha¨fer, Jo¨rg Schibler, Reinhold Schoon, Regina Smolnik, Thomas Terberger and Ingrid Ulbricht. We are grateful to Ulrich Schmo¨lcke, Michael Forster, Peter Forster and Aikaterini Glykou for their support and comments on the manuscript. We also thank many institutions and individuals that provided sample material and access to collections, especially the curators of the Museum fu¨r Naturkunde, Berlin; Muse´um National d0 Histoire Naturelle, Paris; Smithsonian Institution, National Museum of Natural History, Washington D.C.; Zoologische Staatssammlung, Mu¨nchen; Museum fu¨r Haustierkunde, Halle; the American Museum of Natural History, New-York. This work was funded by the Graduate School âHuman Development in Landscapesâ at Kiel University (CAU) and supported by NERC project Grant NE/F003382/1. Radiocarbon dating was carried out at the Leibniz Laboratory, CAU. This work is licensed under a Creative Commons AttributionNonCommercial-NoDerivs 3.0 Unported License.Peer reviewedPublisher PD
Reduced order models for control of fluids using the Eigensystem Realization Algorithm
In feedback flow control, one of the challenges is to develop mathematical
models that describe the fluid physics relevant to the task at hand, while
neglecting irrelevant details of the flow in order to remain computationally
tractable. A number of techniques are presently used to develop such
reduced-order models, such as proper orthogonal decomposition (POD), and
approximate snapshot-based balanced truncation, also known as balanced POD.
Each method has its strengths and weaknesses: for instance, POD models can
behave unpredictably and perform poorly, but they can be computed directly from
experimental data; approximate balanced truncation often produces vastly
superior models to POD, but requires data from adjoint simulations, and thus
cannot be applied to experimental data.
In this paper, we show that using the Eigensystem Realization Algorithm (ERA)
\citep{JuPa-85}, one can theoretically obtain exactly the same reduced order
models as by balanced POD. Moreover, the models can be obtained directly from
experimental data, without the use of adjoint information. The algorithm can
also substantially improve computational efficiency when forming reduced-order
models from simulation data. If adjoint information is available, then balanced
POD has some advantages over ERA: for instance, it produces modes that are
useful for multiple purposes, and the method has been generalized to unstable
systems. We also present a modified ERA procedure that produces modes without
adjoint information, but for this procedure, the resulting models are not
balanced, and do not perform as well in examples. We present a detailed
comparison of the methods, and illustrate them on an example of the flow past
an inclined flat plate at a low Reynolds number.Comment: 22 pages, 7 figure
On the decay of deformed actinide nuclei
decay through a deformed potential barrier produces significant
mixing of angular momenta when mapped from the nuclear interior to the outside.
Using experimental branching ratios and either semi-classical or
coupled-channels transmission matrices, we have found that there is a set of
internal amplitudes which are essentially constant for all even--even actinide
nuclei. These same amplitudes also give good results for the known anisotropic
particle emission of the favored decays of odd nuclei in the same mass
region.
PACS numbers: 23.60.+e, 24.10.Eq, 27.90.+bComment: 5 pages, latex (revtex style), 2 embedded postscript figures
uuencoded gz-compressed .tar file To appear in Physical Review Letter
Developing a framework for the analysis of power through depotentia
Stakeholder participation in tourism policy-making is usually perceived as providing a means of empowerment. However participatory processes drawing upon stakeholders from traditionally empowered backgrounds may provide the means of removing empowerment from stakeholders. Such an outcome would be in contradiction to the claims that participatory processes improve both inclusivity and sustainability. In order to form an understanding of the sources through which empowerment may be removed, an analytical perspective has been developed deriving from Lukes�s views of power dating from 1974. This perspective considers the concept of depotentia as the removal of �power to� without speculating upon the underlying intent and also provides for the multidimensionality of power to be examined within a single study. The application of this analytical perspective has been tested upon findings of the government-commissioned report of the Countryside and Community Research Unit in 2005. The survey and report investigated the progress of Local Access Forums in England created in response to the Countryside and Rights of Way Act 2000. Consideration of the data from this perspective permits the classification of individual sources of depotentia which can each be addressed and potentially enable stakeholder groups to reverse loss of empowerment where it has occurred
Stationary Flows of the Parabolic Potential Barrier in Two Dimensions
In the two-dimensional isotropic parabolic potential barrier , though it is a model of an unstable system in quantum
mechanics, we can obtain the stationary states corresponding to the real energy
eigenvalue . Further, they are infinitely degenerate. For the first few
eigenstates, we will find the stationary flows round a right angle that are
expressed by the complex velocity potentials .Comment: 12 pages, AmS-LaTeX, 4 figure
Terahertz generation by optical rectification in uniaxial birefringent crystals
The angular dependence of terahertz (THz) emission from birefringent crystals
can differ significantly from that of cubic crystals. Here we consider optical
rectification in uniaxial birefringent materials, such as chalcopyrite
crystals. The analysis is verified in (110)-cut ZnGeP_2 and compared to
(zincblende) GaP. Although the crystals share the same nonzero second-order
tensor elements, the birefringence in chalcopyrite crystals cause the pump
pulse polarization to evolve as it propagates through the crystal, resulting in
a drastically different angular dependence in chalcopyrite crystals. The
analysis is extended to {012}- and {114}-cut chalcopyrite crystals and predicts
more efficient conversion for the {114} crystal cut over the {012}- and
{110}-cuts.Comment: 6 pages, 3 figure, online journal articl
Strengths and limitations of a tool for monitoring and evaluating First Peoples' health promotion from an ecological perspective
Background: An ecological approach to health and health promotion targets individuals and the environmental determinants of their health as a means of more effectively influencing health outcomes. The approach has potential value as a means to more accurately capture the holistic nature of Australian First Peoplesâ health programs and the way in which they seek to influence environmental, including social, determinants of health. Methods: We report several case studies of applying an ecological approach to health program evaluation using a tool developed for application to mainstream public health programs in North America â Richardâs ecological coding procedure. Results: We find the ecological approach in general, and the Richard procedure specifically, to have potential for broader use as an approach to reporting and evaluation of health promotion programs. However, our experience applying this tool in academic and community-based program evaluation contexts, conducted in collaboration with First Peoples of Australia, suggests that it would benefit from cultural adaptations that would bring the ecological coding procedure in greater alignment with the worldviews of First Peoples and better identify the aims and strategies of local health promotion programs. Conclusions: Establishing the cultural validity of the ecological coding procedure is necessary to adequately capture the underlying program activities of community-based health promotion programs designed to benefit First Peoples, and its collaborative implementation with First Peoples supports a human rights approach to health program evaluation.Kevin Rowley, Joyce Doyle, Leah Johnston, Rachel Reilly, Leisa McCarthy, Mayatili Marika, Therese Riley, Petah Atkinson, Bradley Firebrace, Julie Calleja and Margaret Carg
An exploratory study looking at the relationship marketing techniques used in the music festival industry
There are current issues and trends in the music festival
market, which may affect the success of an event, and market saturation
is at the forefront of these issues. Previous literature, maintaining
the need for a marketing approach to festivals, identifi es the need
for maintaining strong stakeholder relationships in order to succeed
in a business environment; attention has been focused to the theory
of relationship marketing (RM) because of the recognition that this
practice is complementary to the marketing of festivals. The very nature
of the music festival as an annual, usually, 4-day event means that
effective marketing is needed to keep connections with the consumer
throughout the year. This article focuses on the RM techniques
utilised within the music festival industry from the viewpoint of the
festival organiser in an attempt to establish how festival organisations
value and monitor organisational relationships. This article explores
the extent to which these relationships are valued and managed;
furthermore, the variations between these intricate relationships
are considered by focusing on those held with the organisation â s
consumers and sponsors, the results of which have provided the
ability to establish the importance and relevance of RM to the industry
and further identify the marketing communication methods employed
to establish and maintain such relationships. In-depth, convergent
interviews have been conducted with a segment of music festival
organisers from a range of events. The results have been integrated
with the study of current literature to best exemplify these issues. It
has been established that RM has a strong role in today â s commercial
and independent music festival industry; technological advances are
enabling the organiser to support online relationships further and
increase consumer loyalty. There is a need to expand the research
further because of the complexity of organisational relationships and
the varying categories of festivals
Standard Model Contributions to the Neutrino Index of Refraction in the Early Universe
With the standard electroweak interactions, the lowest-order coherent forward
scattering amplitudes of neutrinos in a CP symmetric medium (such as the early
universe) are zero, and the index of refraction of a propagating neutrino can
only arise from the expansion of gauge boson propagators, from radiative
corrections, and from new physics interactions. Motivated by nucleosynthesis
constraints on a possible sterile neutrino (suggested by the solar neutrino
deficit and a possible neutrino), we calculate the standard model
contributions to the neutrino index of refraction in the early universe,
focusing on the period when the temperature was of the order of a few . We
find sizable radiative corrections to the tree level result obtained by the
expansion of the gauge boson propagator. For the leading log correction is about , while for
the correction is about
. Depending on the family mixing (if any), effects from different family
scattering can be dominated by radiative corrections. The result for
is zero at one-loop level, even if neutrinos are
massive. The cancellation of infrared divergence in a coherent process is also
discussed.Comment: 46pp, 13 figures (not included), UPR-0495
SU(16) grandunification: breaking scales, proton decay and neutrino magnetic moment
We give a detailed renormalization group analysis for the SU(16) grandunified
group with general breaking chains in which quarks and leptons transform
separately at intermediate energies. Our analysis includes the effects of Higgs
bosons. We show that the grandunification scale could be as low as GeV and give examples where new physics could exist at relatively low
energy ( GeV). We consider proton decay in this model and show that
it is consistent with a low grandunification scale. We also discuss the
possible generation of a neutrino magnetic moment in the range of to
with a very small mass by the breaking of the embedded
SU(2) symmetry at a low energy.Comment: (16 pages in REVTEX + 6 figures not included) OITS-49
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