1,044 research outputs found

    Impact of the Cusa and Operative Ultrasound on Hepatic Resection

    Get PDF
    New technologies have been developed for liver surgery, and, like all new technologies, they have a glamour which makes them seem desirable. There is an understanding abroad that they make liver surgery easier and open up the field to those without special training. But there is no proof that the new devices are in any way cost-effective, and certainly no proof that liver surgery has become safer since their advent. Fifty consecutive elective liver resections have been studied, almost half performed with the aid of the ultrasonic dissector and aspirator and diagnostic intraoperative ultrasound. There was no mortality in the whole group, but a 24% morbidity. Operative diagnostic ultrasound was thought to allow more precise planning of surgery. Its use was not associated with any increase in operative time, nor was there any increase in postoperative morbidity. The ultrasonic dissector and aspirator improved technique, reflected in a lower blood loss for each case, in fewer transfusions required, in a shorter postoperative hospital stay and in an ability to achieve these benefits in older patients. Neither device could be said to offer an entree to instant liver surgery. The use of the two devices apparently offered savings measured by a fall in the median postoperative hospital stay of 4.5 days, by a saving of 700 mls in median blood requirement and by a fall in transfusion rate from 64% to 9%

    Obstructive Jaundice in Chronic Pancreatitis

    Get PDF
    Significant obstructive jaundice in chronic pancreatitis is generally considered to be rare. Eleven of 57 consecutive patients with proven chronic pancreatitis have developed significant obstructive jaundice of more than transient duration. Eight presented as jaundice complicating known pancreatitis and three as jaundice of unknown cause

    Batalin-Vilkovisky formalism in perturbative algebraic quantum field theory

    Full text link
    On the basis of a thorough discussion of the Batalin-Vilkovisky formalism for classical field theory presented in our previous publication, we construct in this paper the Batalin-Vilkovisky complex in perturbatively renormalized quantum field theory. The crucial technical ingredient is a proof that the renormalized time-ordered product is equivalent to the pointwise product of classical field theory. The renormalized Batalin-Vilkovisky algebra is then the classical algebra but written in terms of the time-ordered product, together with an operator which replaces the ill defined graded Laplacian of the unrenormalized theory. We identify it with the anomaly term of the anomalous Master Ward Identity of Brennecke and D\"utsch. Contrary to other approaches we do not refer to the path integral formalism and do not need to use regularizations in intermediate steps.Comment: 34 page

    Stability in Designer Gravity

    Full text link
    We study the stability of designer gravity theories, in which one considers gravity coupled to a tachyonic scalar with anti-de Sitter boundary conditions defined by a smooth function W. We construct Hamiltonian generators of the asymptotic symmetries using the covariant phase space method of Wald et al.and find they differ from the spinor charges except when W=0. The positivity of the spinor charge is used to establish a lower bound on the conserved energy of any solution that satisfies boundary conditions for which WW has a global minimum. A large class of designer gravity theories therefore have a stable ground state, which the AdS/CFT correspondence indicates should be the lowest energy soliton. We make progress towards proving this, by showing that minimum energy solutions are static. The generalization of our results to designer gravity theories in higher dimensions involving several tachyonic scalars is discussed.Comment: 29 page

    Are meat options preferred to comparable vegetarian options? An experimental study.

    Get PDF
    OBJECTIVE: Reducing meat consumption would have substantial benefits both in terms of health and environmental impact, but meat options may be more attractive to customers than meat-free options. This study tested this by presenting UK adults (n = 540) with a series of pictures showing two meal options and asking them to select which they would prefer to eat right now. They completed this task for every possible pair from a pool of six comparator meat-based options and six target options (66 pairs). Participants all saw identical comparator options, and were randomised to see the same pictures of target options but with descriptions that suggested they were either meat-based or vegetarian. RESULTS: Selections were used to rank the options for each individual from 1 (most-selected) to 12 (least-selected). Vegetarian target options were ranked worse [by 1.23 places (95% CI: 1.02, 1.44)] than meat target options. Higher self-reported consumption of meat predicted worse mean rankings of target options when these were vegetarian, but not when target options were meat-based. This suggests meat options are preferred to equivalent vegetarian options and may be more likely to be selected. This has implications for interventions aiming to reduce meat consumption to make diets healthier and more sustainable

    Further restrictions on the topology of stationary black holes in five dimensions

    Full text link
    We place further restriction on the possible topology of stationary asymptotically flat vacuum black holes in 5 spacetime dimensions. We prove that the horizon manifold can be either a connected sum of Lens spaces and "handles" S1×S2S^1 \times S^2, or the quotient of S3S^3 by certain finite groups of isometries (with no "handles"). The resulting horizon topologies include Prism manifolds and quotients of the Poincare homology sphere. We also show that the topology of the domain of outer communication is a cartesian product of the time direction with a finite connected sum of R4,S2×S2\mathbb R^4,S^2 \times S^2's and CP2CP^2's, minus the black hole itself. We do not assume the existence of any Killing vector beside the asymptotically timelike one required by definition for stationarity.Comment: LaTex, 22 pages, 9 figure

    Protecting the conformal symmetry via bulk renormalization on Anti deSitter space

    Get PDF
    The problem of perturbative breakdown of conformal symmetry can be avoided, if a conformally covariant quantum field phi on d-dimensional Minkowski spacetime is viewed as the boundary limit of a quantum field Phi on d+1-dimensional anti-deSitter spacetime (AdS). We study the boundary limit in renormalized perturbation theory with polynomial interactions in AdS, and point out the differences as compared to renormalization directly on the boundary. In particular, provided the limit exists, there is no conformal anomaly. We compute explicitly the "fish diagram" on AdS_4 by differential renormalization, and calculate the anomalous dimension of the composite boundary field phi^2 with bulk interaction Phi^4.Comment: 40 page
    • …
    corecore