918 research outputs found

    CFT4 as SO(4,2)-invariant TFT2

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    54 pages, 7 figures; version 2: Published version - extended discussion of CFT4/TFT2 in terms of emergent space-time; refs added; typos correctedOpen Access funded by SCOAP³ - Sponsoring Consortium for Open Access Publishing in Particle Physic

    From Matrix Models and quantum fields to Hurwitz space and the absolute Galois group

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    54 pages, 17 figures54 pages, 17 figures54 pages, 17 figuresWe show that correlators of the hermitian one-Matrix model with a general potential can be mapped to the counting of certain triples of permutations and hence to counting of holomorphic maps from world-sheet to sphere target with three branch points on the target. This allows the use of old matrix model results to derive new explicit formulae for a class of Hurwitz numbers. Holomorphic maps with three branch points are related, by Belyi's theorem, to curves and maps defined over algebraic numbers \bmQ. This shows that the string theory dual of the one-matrix model at generic couplings has worldsheets defined over the algebraic numbers and a target space \mP^1 (\bmQ). The absolute Galois group Gal (\bmQ / \mQ) acts on the Feynman diagrams of the 1-matrix model, which are related to Grothendieck's Dessins d'Enfants. Correlators of multi-matrix models are mapped to the counting of triples of permutations subject to equivalences defined by subgroups of the permutation groups. This is related to colorings of the edges of the Grothendieck Dessins. The colored-edge Dessins are useful as a tool for describing some known invariants of the Gal (\bmQ / \mQ) action on Grothendieck Dessins and for defining new invariants

    Modes of structurally chiral lasers

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    Interactions as intertwiners in 4D QFT

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    42 pages, 3 figures42 pages, 3 figures42 pages, 3 figuresIn a recent paper we showed that the correlators of free scalar field theory in four dimensions can be constructed from a two dimensional topological field theory based on so(4,2) equivariant maps (intertwiners). The free field result, along with results of Frenkel and Libine on equivariance properties of Feynman integrals, are developed further in this paper. We show that the coefficient of the log term in the 1-loop 4-point conformal integral is a projector in the tensor product of so(4,2) representations. We also show that the 1-loop 4-point integral can be written as a sum of four terms, each associated with the quantum equation of motion for one of the four external legs. The quantum equation of motion is shown to be related to equivariant maps involving indecomposable representations of so(4,2), a phenomenon which illuminates multiplet recombination. The harmonic expansion method for Feynman integrals is a powerful tool for arriving at these results. The generalization to other interactions and higher loops is discussed

    A patient's experience of a new post-operative patient-controlled analgesic technique

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    A patient underwent major spinal surgery, twice within a 3 week period. On the first occasion his post-operative pain was managed by conventional morphine patient-controlled analgesia (PCA). After the second procedure his pain was managed by a patient-controlled computer-assisted titration of alfentanil. This provided the opportunity to compare the efficacy of these two drug regimens in the same subject. The results showed comparable quality of analgesia and sedation and similar effects on respiration. However, the patient expressed a preference for morphine PCA.published_or_final_versio

    Kepadatan Populasi dan Sebaran Cacing Tanah di Lahan Sawah Sistem Pertanian Organik, Semi Organik dan Konvensinal

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    Earthworm is one of the soil macrofauna, which consumes organic matter for body growth and life. Therefore the earthworm can be soil organic status and soil fertility indicator. On the other hand, at present, the organic farming system is developing and positively accepted by people as yield consumer, and yield price is higher than conventional yield price. The experimen to study the earthworm population rate and spread methode was conducted in 2008 planting season, in West Java, with RBD (Randomized Block Design). Three farming system as treatment i.e Organic farming, Semi organic and Conventional farming system and six location as replication. The result showed that Semi organic farming system is the most earthworm population rate and the earthworm distribution is random model

    Peri-operative administration of rectal diclofenac sodium. The effect on renal function in patients undergoing minor orthopaedic surgery

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    In a randomized, double-blind study, we administered placebo and diclofenac sodium 100 mg suppositories 1 h pre-operatively and on the first post-operative morning to 22 adult patients undergoing minor orthopaedic surgery. A standardized post-operative intravenous fluid regimen was instituted until oral fluids were tolerated. Renal function was assessed pre-operatively, and on the first and second post-operative days by the measurement of urine output, creatinine, urea, sodium, potassium and NAG (N-acetyl-b-D-glucosaminidase) levels and serum creatinine, urea, sodium and potassium concentrations. On the first postoperative day, the diclofenac group demonstrated a reduced urinary sodium excretion. On the second postoperative day, a reduced urinary NAG/creatinine ratio was observed in the diclofenac group when compared to placebo. We conclude that peri-operative administration of diclofenac causes changes in renal function consistent with prostaglandin inhibition on the first post-operative day but had no lasting adverse effects in this group of patients. Our results reinforce the need for caution when administering this drug in the context of pre-existing renal impairment.published_or_final_versio

    The effect of premedication on oxygen saturation during the post-premedication period in 20 Chinese children undergoing elective surgery

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    Peri-operative continuous pulse oximetric data were studied in healthy Chinese children randomly allocated to receive either pethidine 1 mg kg-1 and atropine 0.02 mg kg-1 intramuscularly 90 min prior to surgery (n=10), or midazolam 0.5 mg kg-1 and atropine 0.02 mg kg-1 orally, 120 min before surgery (n=10). Data were collected during the night before surgery, after premedication and for 8h post-operatively. The pulse oximeter (Nellcor N-200E) output was retrospectively evaluated using Satmaster(®), a computer programme which permits storage, retrieval, signal evaluation and compilation of oximetric data. There was no significant difference in the frequency, duration, or magnitude of desaturation episodes recorded during the post-premedication period compared to the desaturation episodes which occurred in the same child during normal sleep, on the night before surgery. Furthermore, there was no significant difference in the desaturation data between the two premedicant regimens. No child recorded a genuine desaturation less than 80% for longer than 15s at any time during the study. Neither regimen significantly depressed saturation in otherwise healthy children presenting for minor surgical procedures.published_or_final_versio
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