Study of double parton scattering using W+2-jet events in proton-proton collisions at √s=7 TeV

Peer reviewe

Real-Time In Vivo Imaging of Early Mucosal Changes during Ischemia-Reperfusion in Human Jejunum

BACKGROUND AND STUDY AIMS: Small intestinal ischemia-reperfusion (IR) is a frequent, potentially life threatening phenomenon. There is a lack of non-invasive diagnostic modalities. For many intestinal diseases, visualizing the intestinal mucosa using endoscopy is gold standard. However, limited knowledge exists on small intestinal IR-induced, early mucosal changes. The aims of this study were to investigate endoscopic changes in human jejunum exposed to IR, and to study concordance between endoscopic appearance and histology. PATIENTS AND METHODS: In 23 patients a part of jejunum, to be removed for surgical reasons, was isolated and selectively exposed to ischemia with 0, 30 or 120 minutes of reperfusion. In 3 patients, a videocapsule was inserted in the isolated segment before exposure to IR, to visualize the mucosa. Endoscopic view at several time points was related to histology (Heamatoxylin & Eosin) obtained from 20 patients. RESULTS: Ischemia was characterized by loss of villous structure, mucosal whitening and appearance of punctate lesions. This was related to appearance of subepithelial spaces and breaches in the epithelial lining in the histological view. Early during reperfusion, the lumen filled with IR-damaged, shed cells and VCE showed mucosal erosions, hemorrhage and intraluminal debris. At 60 minutes of reperfusion, the only remaining signs of IR were loss of villous structure and small erosions, indicating rapid mucosal healing. CONCLUSIONS: This study shows a unique, real-time in vivo endoscopic view of early mucosal changes during IR of the human small intestine. Future studies should evaluate its usefulness in diagnosis of patients suspected of IR

Measurement of WZ and ZZ production in pp collisions at sqrt{s}=8TeV in final states with b-tagged jets

Measurements are reported of the WZ and ZZ production cross sections in proton-proton collisions at in final states where one Z boson decays to b-tagged jets. The other gauge boson, either W or Z, is detected through its leptonic decay (either , or , , or ). The results are based on data corresponding to an integrated luminosity of 18.9 fb collected with the CMS detector at the Large Hadron Collider. The measured cross sections, and , are consistent with next-to-leading order quantum chromodynamics calculations

Alignment of the CMS silicon tracker during commissioning with cosmic rays

The CMS silicon tracker, consisting of 1440 silicon pixel and 15 148 silicon strip detector modules, has been aligned using more than three million cosmic ray charged particles, with additional information from optical surveys. The positions of the modules were determined with respect to cosmic ray trajectories to an average precision of 3-4 microns RMS in the barrel and 3-14 microns RMS in the endcap in the most sensitive coordinate. The results have been validated by several studies, including laser beam cross-checks, track fit self-consistency, track residuals in overlapping module regions, and track parameter resolution, and are compared with predictions obtained from simulation. Correlated systematic effects have been investigated. The track parameter resolutions obtained with this alignment are close to the design performance