Unveiling the Merger Structure of Black Hole Binaries in Generic Planar Orbits.

The precise modeling of binary black hole coalescences in generic planar orbits is a crucial step to disentangle dynamical and isolated binary formation channels through gravitational-wave observations. The merger regime of such coalescences exhibits a significantly higher complexity compared to the quasicircular case, and cannot be readily described through standard parametrizations in terms of eccentricity and anomaly. In the spirit of the effective one body formalism, we build on the study of the test-mass limit, and introduce a new modeling strategy to describe the general-relativistic dynamics of two-body systems in generic orbits. This is achieved through gauge-invariant combinations of the binary energy and angular momentum, such as a dynamical "impact parameter" at merger. These variables reveal simple "quasi-universal" structures of the pivotal merger parameters, allowing us to build an accurate analytical representation of generic (bounded and dynamically bounded) orbital configurations. We demonstrate the validity of these analytical relations using 311 numerical simulations of bounded noncircular binaries with progenitors from the RIT and SXS catalogs, together with a custom dataset of dynamical captures generated using the Einstein Toolkit, and test-mass data in bound orbits. Our modeling strategy lays the foundations of accurate and complete waveform models for systems in arbitrary orbits, bolstering observational explorations of dynamical formation scenarios and the discovery of new classes of gravitational wave sources.

Demonstration of a hybrid A-RoF/VLC system for beyond 5G applications.

This work reports the implementation of a fiber-optics and visible light communication (VLC)-based flexible optical distribution network for beyond the fifth generation of mobile networks (B5G) applications. The proposed hybrid architecture is composed of a 12.5-km single-mode fiber fronthaul based on the analog radio-over-fiber (A-RoF) technology, followed by a red, green, and blue (RGB)-based VLC link of 1.2 m. As a proof of concept, we experimentally demonstrate a successful deployment of a 5G hybrid A-RoF/VLC system without using pre-/post-equalization, digital pre-distortion, or individual filters for each color, by means of using a dichroic cube filter at the receiver side. The system performance is evaluated in terms of the root mean square error vector magnitude (E V M R M S ), in accordance with the 3rd Generation Partnership Project requirements, and as a function of the light-emitting diodes' injected electrical power and signal bandwidth.

Septoplasty Training During the COVID-19 Era: Development and Validation of a Novel Low-Cost Simulation Model.

Objective: In a context of increasingly limited surgical exposition, enhanced by the coronavirus disease 2019 (COVID-19) pandemic context, the objective of this article is to explain the development of a novel low-cost and simple replication animal-based septoplasty training model for otolaryngology residents, to assess its face and construct validity, and to validate a specific rating scale for each task. Study Design: Experimental study. Setting: Surgical simulation laboratory. Methods: Septoplasty experts divided the procedure into key tasks. A simulator model to perform tasks was developed using pig ears to imitate human nasal septum cartilage, and a Specific Rating Scale was constructed. Trainees and faculty performed all tasks in the model. The participants were videotaped, and operative time, hand movements, and path length were recorded using a motion sensor device. Two blinded experts evaluated the videos with Global and Specific Rating Scales. All participants answered a satisfaction survey. Results: Fifteen subjects were recruited (7 trainees and 8 faculty). Significantly higher Global Rating Scale score, shorter operative time and path length, and fewer hand movements were observed in the faculty group. The satisfaction survey showed high applicability to a real scenario (mean score of 4.6 out of 5). Specific Rating Scale showed construct and concurrent validity and high reliability. Conclusion: This simulation model and its specific rating scale can be accurately used as a validated surgical assessment tool for endonasal septoplasty skills. Its low cost and simple replicability make it a potentially useful tool in any otolaryngology surgical training program.

Protection for Otolaryngologic Surgery in the COVID-19 Pandemic.

OBJECTIVE: The coronavirus disease 2019 (COVID-19) has placed unprecedented challenges on the world and the medical community. It is transmitted through droplets, contact, the fecal-oral route, and airborne transmission under certain conditions that allow droplets to combine with air particles to form an aerosol. Viral loads are higher in the nasal area and similar in symptomatic and asymptomatic patients. Medical situations have been classified into high and low risk of generating aerosols. Most procedures and surgery in otolaryngology correspond to high-risk medical situations. This review aims to gather the vast amount of available information and generate recommendations for different surgical procedures according to aerosolization risk and COVID-19 status, with use of specific personal protective equipment in each case. DATA SOURCES: PubMed, MEDLINE, and Embase. Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, and Food and Drug Administration. REVIEW METHODS: We conducted a review on the literature on personal protective equipment for otolaryngologic surgery and surgical indication restrictions during the COVID-19 pandemic. CONCLUSIONS: SARS-CoV-2 is an easily transmitted virus. Asymptomatic and symptomatic patients with COVID-19 present an upper airway high viral load, conferring otolaryngologic procedures a high risk of aerosolization. Surgical procedures must be categorized according to aerosolization risk and the possibility of COVID-19 diagnosis, according to use of personal protective equipment. IMPLICATIONS FOR PRACTICE: This review contributes to scientific knowledge regarding the detailed description of protective personal equipment and, most important, surgical recommendations to reduce the risk of infection in the otolaryngology community during the COVID-19 pandemic.

(2+1)-dimensional charged black hole in topologically massive electrodynamics.

The 2+1 black hole coupled to a Maxwell field can be charged in two different ways. Besides a Coulomb field, whose potential grows logarithmically in the radial coordinate, there also exists a topological charge due to the existence of a noncontractible cycle. The topological charge does not gravitate and is somehow decoupled from the black hole. This situation changes if one turns on the Chern-Simons term for the Maxwell field. First, the flux integral at infinity becomes equal to the topological charge. Second, demanding regularity of the black hole horizon, the Coulomb charge must vanish identically. Hence, in 2+1 topologically massive electrodynamics coupled to gravity, the black hole can support holonomies only for the Maxwell field. This means that the charged black hole is constructed from the vacuum by means of spacetime identifications.