3,663 research outputs found
Parabolic methods for the construction of spacelike slices of prescribed mean curvature in cosmological spacetimes
Spacelike hypersurfaces of prescribed mean curvature in cosmological space times are constructed as asymptotic limits of a geometric evolution equation. In particular, an alternative, constructive proof is given for the existence of maximal and constant mean curvature slices
Curvature estimates for Weingarten hypersurfaces in Riemannian manifolds
We prove curvature estimates for general curvature functions. As an
application we show the existence of closed, strictly convex hypersurfaces with
prescribed curvature , where the defining cone of is \C_+. is only
assumed to be monotone, symmetric, homogeneous of degree 1, concave and of
class C^{m,\al}, .Comment: 9 pages, v2:final version, to be publishe
Development of a systematic approach to conversion of the ileoanal pouch into continent ileostomy
Based on practical experience, a systematic approach to conversion of ileal J-pouches into continent ileostomies is developed by defining three types of conversion surgery, each with two subtypes. Type 1 refers to conversion without pouch reconstruction, type 2 to partial pouch reconstruction, and type 3 to complete pouch reconstruction. The subdivisions (a and b) take into account whether the afferent loop of the former pelvic pouch (a) or a higher ileal/jejunal segment of the small intestine (b) is used in conversion and/or reconstruction. The six resulting surgical variants are shown in schematic illustrations with accompanying descriptions of technical details to provide the specialized surgeon with comprehensive technical guidance
Renormalization of the antisymmetric tensor field propagator and dynamical generation of the mesons in Resonance Chiral Theory
We discuss the renormalization of the vector meson propagator within
Resonance chiral theory at one loop. Using the particular form of the
interaction Lagrangian we show that additional poles of the renormalized
propagator corresponding to degrees of freedom can be generated. We
give a concrete example of such an effect.Comment: 4 pages, 1 figure, to appear in Proceedings of the conference QCD 08,
Montpellier, 7-12 July 200
Implicit Density Functional Theory
A fermion ground state energy functional is set up in terms of particle
density, relative pair density, and kinetic energy tensor density. It satisfies
a minimum principle if constrained by a complete set of compatibility
conditions. A partial set, which thereby results in a lower bound energy under
minimization, is obtained from the solution of model systems, as well as a
small number of exact sum rules. Prototypical application is made to several
one-dimensional spinless non-interacting models. The effectiveness of "atomic"
constraints on model "molecules" is observed, as well as the structure of
systems with only finitely many bound states.Comment: 9 pages, 4 figure
Conversion of ileo-pouch anal anastomosis to continent ileostomy: strategic surgical considerations and outcome
Aim: The aim was to evaluate surgical strategies for conversion of failed ileo-pouch anal
anastomosis (IPAA) to continent ileostomy (CI), taking morbidity and overall outcome into
account. The hypothesis was that complex conversions are equivalent to the primary
construction of a CI at the time of proctocolectomy.
Method: This was a retrospective analysis of IPAA conversions acknowledging the underlying disease (inflammatory bowel disease [IBD] and non-IBD) and extent of pouch
reconstruction (PR): type 1 (without PR), type 2 (partial PR), and type 3 (complete PR).
Results: Twenty-six patients (IBD, n = 16; non-IBD, n = 10) were converted (type 1,
n = 13; type 2, n = 7; and type 3, n = 6).12/26 patients (46.2%) presented postoperative complications directly related to the conversion with scarification of two pouches.
In a mean follow-up time of 7.5 ± 6.6 years, 5/24 patients required revisional surgery.
Of these, three required pouch excision. The cumulative probability of reoperation at
the end of the second year increased to 21.7% and remained constant thereafter until
the maximum follow-up time of 26 years. The total pouch loss rate was 19.2% (5/26), of
which all occurred in the first 3 years. No statistically significant differences were found
between the conversion types, complications or pouch survival. For all parameters, IBD
patients performed slightly unfavourably. Due to the overall small number of respective
patients, a differentiated investigation of IBD was not performed.
Conclusion: Complex conversion procedures (types 1 and 2) deliver comparable longterm results to new constructions (type 3), thereby limiting the loss of small bowel. IBD
compromises outcome versus non-IBD
Determination of the Chiral Couplings L_10 and C_87 from Semileptonic Tau Decays
Using recent precise hadronic tau-decay data on the V-A spectral function,
and general properties of QCD such as analyticity, the operator product
expansion and chiral perturbation theory, we get accurate values for the QCD
chiral order parameters L_10^r(M_rho) and C_87^r(M_rho). These two low-energy
constants appear at order p^4 and p^6, respectively, in the chiral perturbation
theory expansion of the V-A correlator. At order p^4 we obtain L_10^r(M_rho) =
-(5.22\pm 0.06)10^{-3}. Including in the analysis the two-loop (order p^6)
contributions, we get L_10^r(M_rho) = -(4.06\pm 0.39)10^{-3} and C_87^r(M_rho)
= (4.89\pm 0.19)10^{-3}GeV^{-2}. In the SU(2) chiral effective theory, the
corresponding low-energy coupling takes the value \overline l_5 = 13.30 \pm
0.11 at order p^4, and \overline l_5 = 12.24 \pm 0.21 at order p^6.Comment: 17 pages, 3 figures, v2: Added reference, published versio
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