836 research outputs found
Benchmark Calculations for the Triton Binding Energy for Modern NN Forces and the pi-pi Exchange Three-Nucleon Force
We present high precision benchmark calculations for the triton binding
energy using the most recent, phase equivalent realistic nucleon-nucleon (NN)
potentials and the Tuscon-Melbourne pi-pi three-nucleon force (3NF). That 3NF
is included with partial waves up to a total two-body angular momentum of
j_max=6. It is shown that the inclusion of the 3NF slows down the convergence
in the partial waves and j_max=5 is needed in order to achieve converged
results within a few keV. We adjust the cut-off parameter Lambda in the form
factors of the Tuscon-Melbourne 3NF separately for the different NN potentials
to the triton binding energy. This provides a set of phenomenological
three-nucleon Hamiltonians which can be tested in three-nucleon scattering and
systems with A>3. A connection between the probability to find two nucleons at
short distances in the triton and the effect of that 3NF on the triton binding
energy is pointed out.Comment: 18 pages REVTeX, 3 figure
Modern NN Force Predictions for the Total ND Cross Section up to 300 MeV
For several modern nucleon-nucleon potentials state-of-the-art Faddeev
calculations are carried out for the total cross section between 10 and
300 MeV projectile energy and compared to new high precision measurements. The
agreement between theory and data is rather good, with exception at the higher
energies where a 10% discrepancy builds up. In addition the convergence of the
multiple scattering series incorporated in the Faddeev scheme is studied
numerically with the result, that rescattering corrections remain important.
Based on this multiple scattering series the high energy limit of the total
cross section is also investigated analytically. In contrast to the naive
expectation that the total cross section is the sum of the and
total cross sections we find additional effects resulting from the rescattering
processes, which have different signs and different behavior as function of the
energy. A shadowing effect in the high energy limit only occurs for energies
higher than 300 MeV. The expressions in the high energy limit have
qualitatively a similar behavior as the exactly calculated expressions, but can
be expected to be valid quantitatively only at much higher energies.Comment: 22 pages, 5 figure
Discrepancies in Determinations of the Ginzburg-Landau Parameter
Long-standing discrepancies within determinations of the Ginzburg-Landau
parameter from supercritical field measurements on superconducting
microspheres are reexamined. The discrepancy in tin is shown to result from
differing methods of analyses, whereas the discrepancy in indium is a
consequence of significantly differing experimental results. The reanalyses
however confirms the lower determinations to within experimental
uncertainties.Comment: submitted to Phys. Rev.
Charge-Dependence of the Nucleon-Nucleon Interaction
Based upon the Bonn meson-exchange-model for the nucleon-nucleon ()
interaction, we calculate the charge-independence breaking (CIB) of the
interaction due to pion-mass splitting. Besides the one-pion-exchange (OPE), we
take into account the -exchange model and contributions from three and
four irreducible pion exchanges. We calculate the CIB differences in the
effective range parameters as well as phase shift differences for
partial waves up to total angular momentum J=4 and laboratory energies below
300 MeV. We find that the CIB effect from OPE dominates in all partial waves.
However, the CIB effects from the model are noticable up to D-waves and
amount to about 40% of the OPE CIB-contribution in some partial waves, at 300
MeV. The effects from 3 and 4 contributions are negligible except in
and .Comment: 12 pages, RevTex, 14 figure
Arthritis induced by posttranslationally modified (citrullinated) fibrinogen in DR4-IE transgenic mice
Rheumatoid arthritis (RA) is a common autoimmune disease that afflicts the synovium of diarthrodial joints. The pathogenic mechanisms inciting this disease are not fully characterized, but may involve the loss of tolerance to posttranslationally modified (citrullinated) antigens. We have demonstrated that this modification leads to a selective increase in antigenic peptide affinity for major histocompatibility complex (MHC) class II molecules that carry the RA-associated shared epitope, such as HLA-DRB1*0401 (DR4). We describe the induction of arthritis in DR4-IE transgenic (tg) mice with citrullinated fibrinogen, a protein commonly found in inflamed synovial tissue and a frequent target of autoantibodies in RA patients. The disease induced in these mice was characterized by synovial hyperplasia followed by ankylosis, but lacked a conspicuous polymorphonuclear cell infiltrate. Immunological analysis of these mice through T cell epitope scanning and antibody microarray analysis identified a unique profile of citrulline-specific reactivity that was not found in DR4-IE tg mice immunized with unmodified fibrinogen or in wild-type C57BL/6 mice immunized with citrullinated fibrinogen, two conditions where arthritis was not observed. These observations directly implicate citrullinated fibrinogen as arthritogenic in the context of RA-associated MHC class II molecules
Spatial planning and health systems: enhancing territorial governance in Alpine Space
ABSTRACT: Health systems in Europe are currently facing numerous critical challenges; demographic change is only one example. In order to successfully cope with those challenges on a long-term perspective, effective territorial governance can positively address upcoming issues in this context. Accordingly, the purpose of this research is to contribute to the enhancement of territorial governance in the Alpine Space (AS) with regard to spatial planning and health systems. The aim is to identify main achievements of previous AS projects funded by the European Union (EU) as well as lessons learned from their realization in order to derive valuable implications for amended health and spatial planning policy development. This includes issues such as transnational needs, potential synergies as well as institutional responsibilities and competences required. Besides the goals, approaches and outputs, also problems and difficulties experienced during the projects are analysed. The unit of analyses are 10 implemented projects of the current AS programming period which can provide achievements of valuable interest in this thematic field. INITIAL SITUATION Demographic change is only one of numerous critical challenges health systems in Europe are currently facing. In order to successfully cope with such challenges on a long-term perspective, changes in present health models and governance of health systems are required. Many highly relevant issues in this context such as the need to improve the quality of life and healthcare of elderly people as well as the provision of access to care for people in medically underserved areas are related to the subjects of 'health systems' and 'spatial planning'. Accordingly, the focus of this research is on those two areas. RESEARCH OBJECTIVE AND APPROACH The purpose of this research is to contribute to the enhancement of territorial governance in the AS with regard to spatial planning and health systems. The research objective is to identify main achievements of previous AS projects as well as lessons learned from their realization. The aim is to derive relevant implications for amended policy development, including issues such as transnational needs, potential synergies as well as institutional responsibilities and competences required. To do so, besides the goals, approaches and outputs, also problems and difficulties experienced during the projects are analysed. Both topics, 'health systems' and 'spatial planning', as pillars of territorial governance, need to be addressed on a transnational level in order to generate practically relevant and valid results. Accordingly, the research question is: "What can be learned from EU-funded AS projects with regard to policy development?" The main achievements of these projects are identified in order to derive valuable lessons for future health and spatial planning policy development. RESEARCH METHOD To answer the research question, desk research and questionnaire inquiry was considered the most appropriate approach. Ten projects were selected amongst those promoted by the EU (funded by the "Alpine Space Programme 2007-13" and the "INTERREG IIB Programme 2000-2006"). These projects aim at improving inclusive growth in the Alpine Space under different dimensions through territorial governance. Based on literature review, a structured question
Reconstruction of Northern Hemisphere 1950–2010 atmospheric non-methane hydrocarbons
The short-chain non-methane hydrocarbons (NMHC) are mostly emitted into the
atmosphere by anthropogenic processes. Recent studies have pointed out a
tight linkage between the atmospheric mole fractions of the NMHC ethane and
the atmospheric growth rate of methane. Consequently, atmospheric NMHC are
valuable indicators for tracking changes in anthropogenic emissions,
photochemical ozone production, and greenhouse gases. This study investigates
the 1950–2010 Northern Hemisphere atmospheric C<sub>2</sub>–C<sub>5</sub> NMHC ethane,
propane, <i>i</i>-butane, <i>n</i>-butane, <i>i</i>-pentane, and <i>n</i>-pentane by (a)
reconstructing atmospheric mole fractions of these trace gases using firn air
extracted from three boreholes in 2008 and 2009 at the North Greenland Eemian
Ice Drilling (NEEM) site and applying state-of-the-art models of trace gas
transport in firn, and by (b) considering eight years of ambient NMHC
monitoring data from five Arctic sites within the NOAA Global Monitoring
Division (GMD) Cooperative Air Sampling Network. Results indicate that these
NMHC increased by ~40–120% after 1950, peaked around 1980 (with
the exception of ethane, which peaked approximately 10 yr earlier), and have
since dramatically decreased to be now back close to 1950 levels. The earlier
peak time of ethane vs. the C<sub>3</sub>–C<sub>5</sub> NMHC suggests that different
processes and emissions mitigation measures contributed to the decline in
these NMHC. The 60 yr record also illustrates notable increases in the
ratios of the isomeric <i>iso-/n</i>-butane and <i>iso-/n</i>-pentane
ratios. Comparison of the reconstructed NMHC histories with 1950–2000
volatile organic compounds (VOC) emissions data and with other recently
published ethane trend analyses from ambient air Pacific transect data showed
(a) better agreement with North America and Western Europe emissions than
with total Northern Hemisphere emissions data, and (b) better agreement with
other Greenland firn air data NMHC history reconstructions than with the
Pacific region trends. These analyses emphasize that for NMHC, having
atmospheric lifetimes on the order of < 2 months, the Greenland firn
air records are primarily a representation of Western Europe and North
America emission histories
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