Actinium isotope cross sections for Ra(p,xn) reactions measured at low energies.

Cross sections for production of the medical isotope Ac by the Ra(p,2n) reaction have not previously been measured in fine steps over the relevant energy region, and no measurements are presently available in the literature for the actinium contaminant isotopes created by the adjacent Ra(p,n)Ac and Ra(p,3n)Ac reactions. We report thin-target cross-section measurements for production of Ac and Ac by protons of 15.1-16.

Impacts of technology on children's health: a systematic review.

Objective: To identify the consequences of technology overuse in childhood.

Data Source: A systematic review was carried out in the electronic databases PubMed (National Library of Medicine of the National Institutes of Health) and BVS (Virtual Health Library), considering articles published from 2015 to 2020, in English, Portuguese and Spanish using the terms "Internet", "Child" and "Growth and Development".

Data Synthesis: 554 articles were found and 8 were included in the analysis.

Secrecy Analysis and Error Probability of LIS-Aided Communication Systems under Nakagami- Fading.

Large intelligent surfaces (LIS) are a new trend to achieve higher spectral efficiency and signal-to-noise ratio in mobile communications. For this reason, this paper proposes metrics to analyze the performance of systems with multiple antennas aided by LIS and derive the spectral efficiency, secrecy outage probability, and bit error probability in an environment with Nakagami- distributed fading. In addition to an eavesdropper, there is a single-antenna user, an array of antennas at the transmitter side and the possibility of a direct link between transmitter and receiver.

Large Intelligent Surfaces Communicating Through Massive MIMO Rayleigh Fading Channels.

Large intelligent surfaces (LIS) promises not only to improve the signal to noise ratio, and spectral efficiency but also to reduce the energy consumption during the transmission. We consider a base station equipped with an antenna array using the maximum ratio transmission (MRT), and a large reflector array sending signals to a single user. Each subchannel is affected by the Rayleigh flat fading, and the reflecting elements perform non-perfect phase correction which introduces a Von Mises distributed phase error.