1,459 research outputs found
Analytical eighth-order light-by-light QED contributions from leptons with heavier masses to the anomalous magnetic moment of electron
The important consequences of the recent results of the numerical evaluations
of eighth and tenth order QED contributions to the anomalous magnetic moment of
electron are commented. The correctness of the results of the numerical
evaluation of new eighth order QED corrections to the electron anomaly are
supported by the demonstration of their consistency with the new analytical
expressions for the QED contributions to from the diagrams with
fourth-order light-by-light scattering muon and tau-lepton loops. The
consistency of the similar results are demonstrated in the case of eighth order
massive dependent contribution to the muon anomalous magnetic moment.Comment: 6 pages, LaTeX, The preliminary version of the longer work with the
same title was registered as CERN Preprint during the visit to Theory
Division of CERN in January of 201
Precise mass-dependent QED contributions to leptonic g-2 at order alpha^2 and alpha^3
Improved values for the two- and three-loop mass-dependent QED contributions
to the anomalous magnetic moments of the electron, muon, and tau lepton are
presented. The Standard Model prediction for the electron (g-2) is compared
with its most precise recent measurement, providing a value of the
fine-structure constant in agreement with a recently published determination.
For the tau lepton, differences with previously published results are found and
discussed. An updated value of the fine-structure constant is presented in
"Note added after publication."Comment: 6 pages, 1 figure. v2: New determination of alpha presented (based on
the recent electron g-2 measurement). v3: New formulae added in Sec.IIB. v4:
Updated value of alpha presente
Eighth-Order Vacuum-Polarization Function Formed by Two Light-by-Light-Scattering Diagrams and its Contribution to the Tenth-Order Electron g-2
We have evaluated the contribution to the anomalous magnetic moment of the
electron from six tenth-order Feynman diagrams which contain eighth-order
vacuum-polarization function formed by two light-by-light scattering diagrams
connected by three photons. The integrals are constructed by two different
methods. In the first method the subtractive counter terms are used to deal
with ultraviolet (UV) singularities together with the requirement of
gauge-invariance. In the second method, the Ward-Takahashi identity is applied
to the light-by-light scattering amplitudes to eliminate UV singularities.
Numerical evaluation confirms that the two methods are consistent with each
other within their numerical uncertainties. Combining the two results
statistically and adding small contribution from the muons and/or tau leptons,
we obtain . We also evaluated the
contribution to the muon from the same set of diagrams and found .Comment: 27 page
KHT cold stabilization: A scanning electron microscopy study of the formation of surface deposits on stainless steel in model wines
The incidence of yeast cells and wine polysaccharides and polyphenols in the formation of adherent KHT crystals on stainless steel surfaces during cold stabilization was investigated by scanning electron microscopy. Additives were responsible for differences in the deposit configuration, the crystal shape and size as well as in the KHT crystallization kinetics. Yeast cells act as heterogeneous primary nucleation germs for KHT crystal formation. Colloids from wines interacted with KHT crystal faces and affected growth. It was confirmed that polyphenols strongly inhibit the crystallization and result in small crystals with a unidimensional growth. In contrast, with polyphenols, cubic crystals were obtained when wine polysaccharides were associated with yeast cells
Bias reduction in traceroute sampling: towards a more accurate map of the Internet
Traceroute sampling is an important technique in exploring the internet
router graph and the autonomous system graph. Although it is one of the primary
techniques used in calculating statistics about the internet, it can introduce
bias that corrupts these estimates. This paper reports on a theoretical and
experimental investigation of a new technique to reduce the bias of traceroute
sampling when estimating the degree distribution. We develop a new estimator
for the degree of a node in a traceroute-sampled graph; validate the estimator
theoretically in Erdos-Renyi graphs and, through computer experiments, for a
wider range of graphs; and apply it to produce a new picture of the degree
distribution of the autonomous system graph.Comment: 12 pages, 3 figure
End-colostomy diverticulitis with parastomal phlegmon: A case report.
Acute colonic diverticulitis is a well-known surgical emergency, which occurs in about 10 percent of patients known for diverticulosis.
The case of a 77-year-old woman is reported, with past history of abdominoperineal resection with end-colostomy for low rectal adenocarcinoma, and who developed an acute colonic diverticulitis in a subcutaneous portion of colostomy with parastomal phlegmon.
Initial computed tomography imaging demonstrated a significant submucosal parietal edema with local fat tissues infiltration in regard of 3 diverticula.
A two-step treatment was decided: first a nonoperative treatment was initiated with 2 weeks antibiotics administration, followed by, 6 weeks after, a segmental resection of the terminal portion of the colon with redo of a new colostomy by direct open approach.
Patient was discharged on the second postoperative day without complications. Follow-up at 2 weeks revealed centimetric dehiscence of the stoma, which was managed conservatively until sixth postoperative week by stomatherapists.
Treatment of acute diverticulitis with parastomal phlegmon in a patient with end-colostomy could primary be nonoperative. Delayed surgical treatment with segmental colonic resection was proposed to avoid recurrence and potential associated complications
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