Measurement of the tt̄W and tt̄Z production cross sections in pp collisions at √s = 8 TeV with the ATLAS detector

The production cross sections of top-quark pairs in association with massive vector bosons have been measured using data from pp collisions at s√ = 8 TeV. The dataset corresponds to an integrated luminosity of 20.3 fb−¹ collected by the ATLAS detector in 2012 at the LHC. Final states with two, three or four leptons are considered. A fit to the data considering the tt̄W and tt̄Z processes simultaneously yields a significance of 5.0σ (4.2σ) over the background-only hypothesis for tt¯Wtt¯W (tt̄Z) production. The measured cross sections are σtt̄W = 369 + 100−91 fb and σtt̄Z = 176 + 58−52 fb. The background-only hypothesis with neither tt̄W nor tt̄Z production is excluded at 7.1σ. All measurements are consistent with next-to-leading-order calculations for the tt̄W and tt̄Z processes

The role of simple elbow dislocations in cubitus valgus development in children

PURPOSE: We investigated the functional and radiological outcomes of conservatively treated simple traumatic elbow dislocations and subsequent incidence of cubitus valgus development in children. METHODS: Eleven patients (one female, ten male; mean age 9.8 years, range seven to 12 years) who presented to our hospital with simple elbow dislocations and were conservatively treated between July 2008 and September 2010 were included in the study. All were posterolateral closed dislocations. None of the patients had accompanying elbow fractures. All patients had pre- and postoperative radiographic examinations. The carrying angle of the involved elbow was measured and compared to the contralateral non-injured elbow during follow-up. The incidence and severity of cubitus valgus development was assessed. The functional and clinical outcomes were evaluated using the Mayo Elbow Performance Scale. The mean monitoring period was 24.3 months (range 19–30 months). RESULTS: All patients had satisfactory good and excellent results (85–100 points; mean 96.8 points) according to the Mayo Elbow Performance Scale. The final average elbow flexion was 137° (range, 130–145°) and average extension was 8.6° (range 0–20°) with full supination and pronation in traumatic elbow. Four patients (36.4 %) had an average increase (cubitus valgus) of 14.5° (10–20°) in carrying angle compared to the other elbow. CONCLUSIONS: While isolated traumatic dislocation of the elbow is uncommon among children, it can be successfully treated by urgent closed reduction, proper fixation of the elbow and appropriate timely rehabilitation. However, it should be considered that some patients may develop cubitus valgus deformity in a later period. Therefore, each patient with a simple traumatic elbow dislocation should be followed, and the parents should be informed of the potential for any deformity development