Endoluminal Repair of a Contained Thoracic Aortic Rupture Due to Primary Staphylococcal Aortitis

AbstractWe report a case of primary infectious thoracic aortitis with contained rupture of the descending thoracic aorta caused by Staphylococcus aureus and successfully treated with a rifampicin-rinsed aortic stent graft

The impact of superficial femoral artery (SFA) occlusion on the outcome of proximal sartorius muscle transposition flaps in vascular surgery patients

ObjectivesTo demonstrate the feasibility and safety of proximal sartorius muscle rotational flaps in patients with peripheral occlusive artery disease.MethodsRetrospective analysis of 53 patients with 56 proximal sartorius muscle flaps. Indication for a flap procedure was postoperative calcitrant lymphorrhea in nine, graft at risk in 13, and graft infection in 34 procedures. Pre- and postoperative patencies of the superficial femoral artery (SFA) and profundal femoral artery (PFA) were documented. Flap viability, wound healing, and limb salvage were examined at follow-up.ResultsIn 59% of the procedures in this series, the SFA was occluded. The PFA was patent in all patients. Flap viability (100% vs 94%), rate of new (4% vs 6%), and recurrent infections (9% vs 6%), loss of vascular reconstruction rate (9% vs 9%), and limb salvage rate (100% vs 88%) did not differ significantly between the SFA patent and the SFA occluded group. There were four new infections (7%) and three recurrent infections (5.5%) during follow-up, five of which led to a loss of reconstruction. In four of those five patients, the sartorius flap was viable. Two patients died during the immediate postoperative period from septic multi-organ failure (3%). At a median follow-up of 6.4 months, 54 flaps were viable and wound closure was achieved in all surviving 51 patients. Limb salvage rate was 93%.ConclusionsBiologic protection procedures as local muscle flaps are vital adjuncts to vascular surgery techniques in the treatment of complicated wounds in the groin. Occlusion of the SFA in the presence of a patent PFA is not associated with an increased risk of flap loss in proximal sartorius muscle rotational flaps

The wave equation on singular space-times

We prove local unique solvability of the wave equation for a large class of weakly singular, locally bounded space-time metrics in a suitable space of generalised functions.Comment: Latex, 19 pages, 1 figure. Discussion of class of metrics covered by our results and some examples added. Conclusion more detailed. Version to appear in Communications in Mathematical Physic

Cognitive appraisal as a mechanism linking negative organizational shocks and intentions to leave

The past two decades have seen a significant rise in both frequency and size of mergers and acquisitions in the US, many of which have been associated with considerable interruption of organizational activities and a host of negative outcomes for employees. In this study of 763 US-based airline employees, we identify threat appraisal as a key mechanism explaining the relationship between four change-related variables (quality of change communication, procedural fairness in restructuring, change management history, and anxiety about change) and employee turnover intentions. Results indicate that turnover intentions are influenced by quality of change communication, procedural fairness in restructuring, and anxiety about change as mediated by threat appraisal. We also found that job embeddedness moderated the relationships of quality of change communication and procedural fairness in restructuring with threat appraisal. Our focus on malleable levers of withdrawal offers theoretical and practical insights into how turnover intentions can be influenced

Deflection of Highly Relativistic Particles in a Gravitational Field

A novel approach to the calculation of the deflection of highly relativistic test particles in gravitational fields is described. We make use of the light-like boosts of the gravitational fields of the sources. Examples are given of the deflection of highly relativistic particles in the Schwarzschild and Kerr gravitational fields, in the field of a static, axially symmetric, multipole source and in the field of a cosmic string. The deflection of spinning particles is also discussed.Comment: 18 pages, 2 figures, accepted for publication in Classical and Quantum Gravit

Generalized Fourier Integral Operators on spaces of Colombeau type

Generalized Fourier integral operators (FIOs) acting on Colombeau algebras are defined. This is based on a theory of generalized oscillatory integrals (OIs) whose phase functions as well as amplitudes may be generalized functions of Colombeau type. The mapping properties of these FIOs are studied as the composition with a generalized pseudodifferential operator. Finally, the microlocal Colombeau regularity for OIs and the influence of the FIO action on generalized wave front sets are investigated. This theory of generalized FIOs is motivated by the need of a general framework for partial differential operators with non-smooth coefficients and distributional data

Coupling a Point-Like Mass to Quantum Gravity with Causal Dynamical Triangulations

We present a possibility of coupling a point-like, non-singular, mass distribution to four-dimensional quantum gravity in the nonperturbative setting of causal dynamical triangulations (CDT). In order to provide a point of comparison for the classical limit of the matter-coupled CDT model, we derive the spatial volume profile of the Euclidean Schwarzschild-de Sitter space glued to an interior matter solution. The volume profile is calculated with respect to a specific proper-time foliation matching the global time slicing present in CDT. It deviates in a characteristic manner from that of the pure-gravity model. The appearance of coordinate caustics and the compactness of the mass distribution in lattice units put an upper bound on the total mass for which these calculations are expected to be valid. We also discuss some of the implementation details for numerically measuring the expectation value of the volume profiles in the framework of CDT when coupled appropriately to the matter source.Comment: 26 pages, 9 figures, updated published versio

Isomorphisms of algebras of Colombeau generalized functions

We show that for smooth manifolds X and Y, any isomorphism between the special algebra of Colombeau generalized functions on X, resp. Y is given by composition with a unique Colombeau generalized function from Y to X. We also identify the multiplicative linear functionals from the special algebra of Colombeau generalized functions on X to the ring of Colombeau generalized numbers. Up to multiplication with an idempotent generalized number, they are given by an evaluation map at a compactly supported generalized point on X.Comment: 10 page

Distributional sources for black hole initial data

Black hole initial data is usually produced using Bowen-York type puncture initial data or by applying an excision boundary condition. The benefits of the Bowen-York initial data are the ability to specify the spin and momentum of the system as parameters of the initial data. In an attempt to extend these benefits to other formulations of the Einstein constraints, the puncture method is reformulated using distributions as source terms. It is shown how the Bowen-York puncture black hole initial data and the trumpet variation is generated by distributional sources. A heuristic argument is presented to argue that these sources are the general sources of spin and momentum. In order to clarify the meaning of other distributional sources, an exact family of initial data with generalized sources to the Hamiltonian constraint are studied; spinning trumpet black hole initial data and black hole initial data with higher order momentum sources are also studied.Comment: Code available at https://github.com/SwampWalker/LeapingMonke

Symmetries and geodesics in (anti-)de Sitter spacetimes with nonexpanding impulsive waves

We consider a class of exact solutions which represent nonexpanding impulsive waves in backgrounds with nonzero cosmological constant. Using a convenient 5-dimensional formalism it is shown that these spacetimes admit at least three global Killing vector fields. The same geometrical approach enables us to find all geodesics in a simple explicit form and describe the effect of impulsive waves on test particles. Timelike geodesics in the axially-symmetric Hotta-Tanaka spacetime are studied in detail. It is also demonstrated that for vanishing cosmological constant, the symmetries and geodesics reduce to those for well-known impulsive pp-waves.Comment: 16 pages, 3 figures, LaTeX 2e. To appear in Class. Quantum Gra