812 research outputs found
A sample of religious understanding and beliefs of an urban church congregation
Thesis (M.S.)--Boston Universit
Podoplanin immunopositive lymphatic vessels at the implant interface in a rat model of osteoporotic fractures
Insertion of bone substitution materials accelerates healing of osteoporotic fractures. Biodegradable materials are preferred for application in osteoporotic patients to avoid a second surgery for implant replacement. Degraded implant fragments are often absorbed by macrophages that are removed from the fracture side via passage through veins or lymphatic vessels. We investigated if lymphatic vessels occur in osteoporotic bone defects and whether they are regulated by the use of different materials. To address this issue osteoporosis was induced in rats using the classical method of bilateral ovariectomy and additional calcium and vitamin deficient diet. In addition, wedge-shaped defects of 3, 4, or 5 mm were generated in the distal metaphyseal area of femur via osteotomy. The 4 mm defects were subsequently used for implantation studies where bone substitution materials of calcium phosphate cement, composites of collagen and silica, and iron foams with interconnecting pores were inserted. Different materials were partly additionally functionalized by strontium or bisphosphonate whose positive effects in osteoporosis treatment are well known. The lymphatic vessels were identified by immunohistochemistry using an antibody against podoplanin. Podoplanin immunopositive lymphatic vessels were detected in the granulation tissue filling the fracture gap, surrounding the implant and growing into the iron foam through its interconnected pores. Significant more lymphatic capillaries were counted at the implant interface of composite, strontium and bisphosphonate functionalized iron foam. A significant increase was also observed in the number of lymphatics situated in the pores of strontium coated iron foam. In conclusion, our results indicate the occurrence of lymphatic vessels in osteoporotic bone. Our results show that lymphatic vessels are localized at the implant interface and in the fracture gap where they might be involved in the removal of lymphocytes, macrophages, debris and the implants degradation products. Therefore the lymphatic vessels are involved in implant integration and fracture healing
Low-Energy \Lambda-\p Scattering Parameters from the Reaction
Constraints on the spin-averaged scattering length and effective
range have been obtained from measurements of the reaction
close to the production threshold by comparing model phase-space Dalitz plot
occupations with experimental ones. The data fix well the position of the
virtual bound state in the system. Combining this with information
from elastic scattering measurements at slightly higher energies,
together with the fact that the hyperdeuteron is not bound, leads to a new
determination of the low energy scattering parameters.Comment: 18 pages, 7 figure
Weak strangeness production in nucleon-nucleon scattering
Until now the only way to study the strangeness changing baryon-baryon interaction has been through the decays of lambda hypernuclei. It would clearly be preferable to be able to study reactions such as pn→pΛ in free space. In order to provide some guidance concerning the feasibility of such a measurement, we investigate the energy dependence, parity violating asymmetry, and shape of the cross section for this reaction.J. Haidenbauer, K. Holinde, K. Kilian, T. Sefzick, A. W. Thoma
Testing nonperturbative techniques in the scalar sector of the standard model
We discuss the current picture of the standard model's scalar sector at
strong coupling. We compare the pattern observed in the scalar sector in
perturbation theory up to two-loop with the nonperturbative solution obtained
by a next-to-leading order 1/N expansion. In particular, we analyze two
resonant Higgs scattering processes, ff -> H -> f'f' and ff -> H -> ZZ, WW. We
describe the ingredients of the nonperturbative calculation, such as the
tachyonic regularization, the higher order 1/N intermediate renormalization,
and the numerical methods for evaluating the graphs.
We discuss briefly the perspectives and usefulness of extending these
nonperturbative methods to other theories
Single \pi^- production in np collisions for excess energies up to 90 MeV
The quasifree reaction np\to pp\pim was studied in a kinematically complete
experiment by bombarding a liquid hydrogen target with a deuteron beam of
momentum 1.85 GeV/c and analyzing the data along the lines of the spectator
model. In addition to the three charged ejectiles the spectator proton was also
detected in the large-acceptance time-of-flight spectrometer COSY-TOF. It was
identified by its momentum and flight direction thus yielding access to the
Fermi motion of the bound neutron and to the effective neutron 4-momentum
vector which differed from event to event. A range of almost 90
MeV excess energy above threshold was covered. Energy dependent angular
distributions, invariant mass spectra as well as fully covered Dalitz plots
were deduced. Sizeable FSI effects were found as were contributions of
and partial waves. The behavior of the elementary cross section
close to threshold is discussed in view of new cross section
data. In comparison with existing literature data the results provide a
sensitive test of the spectator model.Comment: 21 pages, 9 figures, 4 tables, submitted to EPJ
Developing hyperpolarized 13C spectroscopy and imaging for metabolic studies in the isolated perfused rat heart
Hyperpolarized 13C magnetic resonance is a powerful tool for the study of cardiac metabolism. In this work, we have implemented protocols for the real-time hyperpolarized 13C investigation of Langendorff-perfused rat hearts using both non-selective non-localized spectroscopy and fast spectroscopic imaging. Following [1-13C] pyruvate infusion, we observed both catabolic and anaplerotic metabolic processes resulting in a number of metabolites, including bicarbonate, carbon dioxide, lactate, alanine and aspartate. Employing fast spectroscopic imaging, we were able to observe regional variations in pyruvate perfusion as well as in lactate and bicarbonate production
UV friendly T-parity in the SU(6)/Sp(6) little Higgs model
Electroweak precision tests put stringent constraints on the parameter space
of little Higgs models. Tree-level exchange of TeV scale particles in a generic
little Higgs model produce higher dimensional operators that make contributions
to electroweak observables that are typically too large. To avoid this problem
a discrete symmetry dubbed T-parity can be introduced to forbid the dangerous
couplings. However, it was realized that in simple group models such as the
littlest Higgs model, the implementation of T-parity in a UV completion could
present some challenges. The situation is analogous to the one in QCD where the
pion can easily be defined as being odd under a new symmetry in the
chiral Lagrangian, but this is not a symmetry of the quark Lagrangian. In
this paper we examine the possibility of implementing a T-parity in the low
energy model that might be easier to realize in the UV. In our
model, the T-parity acts on the low energy non-linear sigma model field in way
which is different to what was originally proposed for the Littlest Higgs, and
lead to a different low energy theory. In particular, the Higgs sector of this
model is a inert two Higgs doublets model with an approximate custodial
symmetry. We examine the contributions of the various sectors of the model to
electroweak precision data, and to the dark matter abundance.Comment: 21 pages,4 figures. Clarifications added, typos corrected and
references added. Published in JHE
Supersymmetry Without Prejudice at the LHC
The discovery and exploration of Supersymmetry in a model-independent fashion
will be a daunting task due to the large number of soft-breaking parameters in
the MSSM. In this paper, we explore the capability of the ATLAS detector at the
LHC ( TeV, 1 fb) to find SUSY within the 19-dimensional
pMSSM subspace of the MSSM using their standard transverse missing energy and
long-lived particle searches that were essentially designed for mSUGRA. To this
end, we employ a set of k previously generated model points in the
19-dimensional parameter space that satisfy all of the existing experimental
and theoretical constraints. Employing ATLAS-generated SM backgrounds and
following their approach in each of 11 missing energy analyses as closely as
possible, we explore all of these k model points for a possible SUSY
signal. To test our analysis procedure, we first verify that we faithfully
reproduce the published ATLAS results for the signal distributions for their
benchmark mSUGRA model points. We then show that, requiring all sparticle
masses to lie below 1(3) TeV, almost all(two-thirds) of the pMSSM model points
are discovered with a significance in at least one of these 11 analyses
assuming a 50\% systematic error on the SM background. If this systematic error
can be reduced to only 20\% then this parameter space coverage is increased.
These results are indicative that the ATLAS SUSY search strategy is robust
under a broad class of Supersymmetric models. We then explore in detail the
properties of the kinematically accessible model points which remain
unobservable by these search analyses in order to ascertain problematic cases
which may arise in general SUSY searches.Comment: 69 pages, 40 figures, Discussion adde
Heavy Quarkonium Effective Theory
We formulate a QCD-based effective theory approach to heavy quarkonia-like
systems as and resonances and states. We apply
the method to inclusive decays, working out a few examples in detail.Comment: 52 pages, LaTeX, 3 uuencoded and compressed figures, uses epsf.sty,
CERN-TH.7468/9
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