University of Ioannina

About: University of Ioannina is a education organization based out in Ioannina, Greece. It is known for research contribution in the topics: Population & Large Hadron Collider. The organization has 7654 authors who have published 20594 publications receiving 671560 citations. The organization is also known as: Panepistimio Ioanninon.

Search for Heavy Neutral Leptons in Events with Three Charged Leptons in Proton-Proton Collisions at √s = 13 TeV

Abstract: A search for a heavy neutral lepton N of Majorana nature decaying into a W boson and a charged lepton is performed using the CMS detector at the LHC. The targeted signature consists of three prompt charged leptons in any flavor combination of electrons and muons. The data were collected in proton-proton collisions at a center-of-mass energy of 13 TeV, with an integrated luminosity of 35.9 fb^(−1). The search is performed in the N mass range between 1 GeV and 1.2 TeV. The data are found to be consistent with the expected standard model background. Upper limits are set on the values of |V_(eN)|^2and |V_(μN)|^2, where V_(lN) is the matrix element describing the mixing of N with the standard model neutrino of flavor l. These are the first direct limits for N masses above 500 GeV and the first limits obtained at a hadron collider for N masses below 40 GeV.

Excessive Tibial Rotation During High-Demand Activities Is Not Restored by Anterior Cruciate Ligament Reconstruction

Abstract: Purpose: Recent in vitro research has suggested that anterior cruciate ligament (ACL) reconstruction does not restore control of tibial rotation. The purpose of this study was to explore these findings in vivo and investigate rotational knee stability during landing and subsequent pivoting. Such an activity places higher demands on the knee, almost similar to those found during high-level sports. Type of Study: Case control series study. Methods: We assessed 11 patients who had undergone ACL reconstruction with the same arthroscopic technique using a bone–patellar tendon–bone graft, 11 ACL-deficient subjects who had sustained the injury more than 1 year prior to testing, and 11 matched controls. Kinematic data were collected (50 Hz) with a 6-camera optoelectronic system while the subjects performed the following task: they jumped off a 40-cm platform and landed on the ground. After foot contact, the subjects were instructed to pivot at 90° and walk away from the platform. The evaluation period was identified from initial foot contact with the ground with both legs, included the pivoting of the ipsilateral leg, and was completed on touchdown of the contralateral leg. Results: Significant differences were found between the reconstructed leg of the ACL group and the healthy control, and between the deficient leg of the ACL-deficient group and the healthy control. We also found no significant differences between the deficient leg of the ACL-deficient group and the reconstructed leg of the ACL reconstructed group. Conclusions: It was concluded that, under high-stress activities, ACL reconstruction may not restore tibial rotation to the previous physiological level, even though anterior tibial translation is restored. Future research on ACL reconstruction should focus on the development of new surgical procedures and/or grafts to address this problem. Level of Evidence: Level III.