Synchronization of quantum communications over an optical classical communications channel.

Precise synchronization between a transmitter and receiver is crucial for quantum communications protocols such as quantum key distribution (QKD) to efficiently correlate the transmitted and received signals and increase the signal-to-noise ratio. In this work, we introduce a synchronization technique that exploits a co-propagating classical optical communications link and tests its performance in a free-space QKD system. Previously, existing techniques required additional laser beams or relied on the capability to retrieve the synchronization from the quantum signal itself; this approach, however, is not applicable in high channel loss scenarios.

Tbit/s line-rate satellite feeder links enabled by coherent modulation and full-adaptive optics.

Free-space optical (FSO) communication technologies constitute a solution to cope with the bandwidth demand of future satellite-ground networks. They may overcome the RF bottleneck and attain data rates in the order of Tbit/s with only a handful of ground stations. Here, we demonstrate single-carrier Tbit/s line-rate transmission over a free-space channel of 53.

Oral syphilis: a series of 5 cases.

Syphilis is an infectious, usually sexually transmitted, disease caused by Treponema pallidum, subspecies pallidum. Because of the increasing prevalence in Europe during the past few years, dentists could be confronted with patients with oral manifestations of syphilis. Because oral lesions are highly contagious, it is vital to make the correct diagnosis quickly to initiate the proper therapy and to interrupt the chain of infection.

Evaluation of location and dimensions of lingual foramina using limited cone-beam computed tomography.

Purpose: To assess retrospectively the frequency and location of mandibular lingual foramina and their bony canals with limited cone-beam computed tomography.

Patients And Methods: Of 389 consecutively taken cone-beam computed tomograms of the mandible, 191 fulfilled the inclusion criteria of adequate quality, dentate areas within the region of interest, and visualization of the mandibular inferior border. Foramina were located according to tooth areas and were grouped into midline, paramedian, and posterior foramina.