alpha_s from tau decays revisited

Being a determination at low energies, the analysis of hadronic tau decay data provides a rather precise determination of the strong coupling alpha_s after evolving the result to M_Z. At such a level of precision, even small non-perturbative effects become relevant for the central value and error. While those effects had been taken into account in the framework of the operator product expansion, contributions going beyond it, so-called duality violations, have previously been neglected. The following investigation fills this gap through a finite-energy sum rule analysis of tau decay spectra from the OPAL experiment, including duality violations and performing a consistent fit of all appearing QCD parameters. The resulting values for alpha_s(M_tau) are 0.307(19) in fixed-order perturbation theory and 0.322(26) in contour-improved perturbation theory, which translates to the n_f=5 values 0.1169(25) and 0.1187(32) at M_Z, respectively.Comment: 4 pages, 3 figures. Prepared for the Proceedings of the International Workshop on e+e- collisions from Phi to Psi (PHIPSI11), Sep. 19-22, 2011, BINP, Novosibirsk, Russi

Duality Violation and the K --> pi pi Electroweak Penguin Operator Matrix Elements from Hadronic Tau Decays

We discuss a preliminary study of the impact of duality violations on extractions from tau decay data of the D=6 VEVs which determine chiral limit Standard Model K-->pi pi matrix elements of the electroweak penguin operators.Comment: 4 pages, 5 figures, prepared for the Proceedings of the 11th Particle and Nuclear Intersections Conference (PANIC 2011), Boston, USA, July 24-29, 201

Chiral Lagrangians

An overview of the field of Chiral Lagrangians is given. This includes Chiral Perturbation Theory and resummations to extend it to higher energies, applications to the muon anomalous magnetic moment, $\epsilon^\prime/\epsilon$ and others.Comment: Invited talk at the XX International Symposium on Lepton and Photon Interactions at High Energies 23rd-28th July 2001, Rome Italy, 15 pages, uses ws-p10x7.cls Changes: 2 references added, numbers in g-2 hadronic changed slightl

In-beam fast-timing measurements in 103,105,107Cd

Fast-timing measurements were performed recently in the region of the medium-mass 103,105,107Cd isotopes, produced in fusion evaporation reactions. Emitted gamma-rays were detected by eight HPGe and five LaBr3:Ce detectors working in coincidence. Results on new and re-evaluated half-lives are discussed within a systematic of transition rates. The $7/2_1^+$ states in 103,105,107Cd are interpreted as arising from a single-particle excitation. The half-life analysis of the $11/2_1^-$ states in 103,105,107Cd shows no change in the single-particle transition strength as a function of the neutron number

Duality violations in tau hadronic spectral moments

Evidence is presented for the necessity of including duality violations in a consistent description of spectral function moments employed in the precision determination of $\alpha_s$ from $\tau$ decay. A physically motivated ansatz for duality violations in the spectral functions enables us to perform fits to spectral moments employing both pinched and unpinched weights. We describe our analysis strategy and provide some preliminary findings. Final numerical results await completion of an ongoing re-determination of the ALEPH covariance matrices incorporating correlations due to the unfolding procedure which are absent from the currently posted versions. To what extent this issue affects existing analyses and our own work will require further study.Comment: 6 pages, 3 figures. Talk given at 11th International Workshop on Tau Lepton Physics, Manchester, UK, 13-17 September 201

Vascularization of the dorsal root ganglia and peripheral nerve of the mouse: Implications for chemical-induced peripheral sensory neuropathies

Although a variety of industrial chemicals, as well as several chemotherapeutic agents used to treat cancer or HIV, preferentially induce a peripheral sensory neuropathy what remains unclear is why these agents induce a sensory vs. a motor or mixed neuropathy. Previous studies have shown that the endothelial cells that vascularize the dorsal root ganglion (DRG), which houses the primary afferent sensory neurons, are unique in that they have large fenestrations and are permeable to a variety of low and high molecular weight agents. In the present report we used whole-mount preparations, immunohistochemistry, and confocal laser scanning microscopy to show that the cell body-rich area of the L4 mouse DRG has a 7 fold higher density of CD31+ capillaries than cell fiber rich area of the DRG or the distal or proximal aspect of the sciatic nerve. This dense vascularization, coupled with the high permeability of these capillaries, may synergistically contribute, and in part explain, why many potentially neurotoxic agents preferentially accumulate and injure cells within the DRG. Currently, cancer survivors and HIV patients constitute the largest and most rapidly expanding groups that have chemically induced peripheral sensory neuropathy. Understanding the unique aspects of the vascularization of the DRG and closing the endothelial fenestrations of the rich vascular bed of capillaries that vascularize the DRG before intravenous administration of anti-neoplastic or anti-HIV therapies, may offer a mechanism based approach to attenuate these chemically induced peripheral neuropathies in these patients

On epsilon_K beyond lowest order in the Operator Product Expansion

We analyse the structure of long distance (LD) contributions to the CP-violating parameter epsilon_K, that generally affect both the absorptive (Gamma_12) and the dispersive (M_12) parts of the K0 -- K0bar mixing amplitude. We point out that, in a consistent framework, in addition to LD contributions to Im(Gamma_12), estimated recently by two of us, also LD contributions to Im(M_12) have to be taken into account. Estimating the latter contributions the impact of LD effects on epsilon_K is significantly reduced (from -6.0 % to -3.6 %). The overall effect of LD corrections and of the superweak phase being different from 45 degrees is summarised by the multiplicative factor kappa_epsilon = 0.94 +/- 0.02.Comment: 10 pages, 2 figures. v3: minor typos fixed. Matches journal versio

Toward a Systematic Holographic QCD: A Braneless Approach

Recently a holographic model of hadrons motivated by AdS/CFT has been proposed to fit the low energy data of mesons. We point out that the infrared physics can be developed in a more systematic manner by exploiting backreaction of the nonperturbative condensates. We show that these condensates can naturally provide the IR cutoff corresponding to confinement, thus removing some of the ambiguities from the original formulation of the model. We also show how asymptotic freedom can be incorporated into the theory, and the substantial effect it has on the glueball spectrum and gluon condensate of the theory. A simple reinterpretation of the holographic scale results in a non-perturbative running for alpha_s which remains finite for all energies. We also find the leading effects of adding the higher condensate into the theory. The difficulties for such models to reproduce the proper Regge physics lead us to speculate about extensions of our model incorporating tachyon condensation.Comment: 27 pages, LaTe

Effect of Colchicine on the Risk of Perioperative Acute Kidney Injury: Clinical Protocol of a Substudy of the Colchicine for the Prevention of Perioperative Atrial Fibrillation Randomized Clinical Trial

Acute kidney injury; Colchicine; Noncardiac surgeryLesión renal aguda; Colchicina; Cirugía no cardiacaLesión renal aguda; Colchicina; Cirugía no cardiacaBackground: Inflammation during and after surgery can lead to organ damage including acute kidney injury. Colchicine, an established inexpensive anti-inflammatory medication, may help to protect the organs from pro-inflammatory damage. This protocol describes a kidney substudy of the colchicine for the prevention of perioperative atrial fibrillation (COP-AF) study, which is testing the effect of colchicine versus placebo on the risk of atrial fibrillation and myocardial injury among patients undergoing thoracic surgery. Objective: Our kidney substudy of COP-AF will determine whether colchicine reduces the risk of perioperative acute kidney injury compared with a placebo. We will also examine whether colchicine has a larger absolute benefit in patients with pre-existing chronic kidney disease, the most prominent risk factor for acute kidney injury. Design and Setting: Randomized, superiority clinical trial conducted in 40 centers in 11 countries from 2018 to 2023. Patients: Patients (~3200) aged 55 years and older having major thoracic surgery. Intervention: Patients are randomized 1:1 to receive oral colchicine (0.5 mg tablet) or a matching placebo, given twice daily starting 2 to 4 hours before surgery for a total of 10 days. Patients, health care providers, data collectors, and outcome adjudicators will be blinded to the randomized treatment allocation. Methods: Serum creatinine concentrations will be measured before surgery and on postoperative days 1, 2, and 3 (or until hospital discharge). The primary outcome of the substudy is perioperative acute kidney injury, defined as an increase (from the prerandomization value) in serum creatinine concentration of either ≥26.5 μmol/L (≥0.3 mg/dL) within 48 hours of surgery or ≥50% within 7 days of surgery. The primary analysis (intention-to-treat) will examine the relative risk of acute kidney injury in patients allocated to receive colchicine versus placebo. We will repeat the primary analysis using alternative definitions of acute kidney injury and examine effect modification by pre-existing chronic kidney disease, defined as a prerandomization estimated glomerular filtration rate (eGFR) <60 mL/min per 1.73 m2. Limitations: The substudy will be underpowered to detect small effects on more severe forms of acute kidney injury treated with dialysis. Results: Substudy results will be reported in 2024. Conclusions: This substudy will estimate the effect of colchicine on the risk of perioperative acute kidney injury in older adults undergoing major thoracic surgery.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The Canadian Institutes of Health Research provided an operating grant for the main COP-AF trial. General Research Fund (14121720), Research Grants Council, Hong Kong Special Administrative Region, China. The Department of Medicine at Western University provided additional financial support for this substudy. In addition, the authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: AXG is supported by the Dr Adam Linton Chair in Kidney Health Analytics. PJ Devereaux is supported by a Tier 1 Canada Research Chair in Perioperative Medicine. CP is a member of the advisory board and owns equity in RenalytixAI. He also serves as a consultant for Genfit and is supported by NIH grants R01HL085757, U01DK114866, U01DK106962, U01DK129984, R01DK093770, and P30DK079310. EP is supported by a research grant from Generalitat de Catalunya (PERIS SLT017/20/000089). MKW is supported by the PSI Foundation—Research Trainee Award. D Conen received speaker fees from Servier Canada and BMS/Pfizer, and he received consulting fees from Trimedics and Roche Diagnostics, all outside of the current work. No funding entity had a role in data collection, statistical analysis, article writing, or the decision to publish