Gravitational Wave Signatures of Black Hole Quasinormal Mode Instability.

Black hole (BH) spectroscopy has emerged as a powerful approach to extracting spacetime information from gravitational wave (GW) observed signals. Yet, quasinormal mode (QNM) spectral instability under small scale perturbations has been recently shown to be a common classical general relativistic phenomenon [J. L.

Cost-Effective Method to Perform SARS-CoV-2 Variant Surveillance: Detection of Alpha, Gamma, Lambda, Delta, Epsilon, and Zeta in Argentina.

SARS-CoV-2 variants with concerning characteristics have emerged since the end of 2020. Surveillance of SARS-CoV-2 variants was performed on a total of 4,851 samples from the capital city and 10 provinces of Argentina, during 51 epidemiological weeks (EWs) that covered the end of the first wave and the ongoing second wave of the COVID-19 pandemic in the country (EW 44/2020 to EW 41/2021). The surveillance strategy was mainly based on Sanger sequencing of a Spike coding region that allows the identification of signature mutations associated with variants.

Understanding the "antikick" in the merger of binary black holes.

The generation of a large recoil velocity from the inspiral and merger of binary black holes represents one of the most exciting results of numerical-relativity calculations. While many aspects of this process have been investigated and explained, the "antikick," namely, the sudden deceleration after the merger, has not yet found a simple explanation. We show that the antikick can be understood in terms of the radiation from a deformed black hole where the anisotropic curvature distribution on the horizon correlates with the direction and intensity of the recoil.

Definition of the key target volume in radiosurgical management of arteriovenous malformations: a new dynamic concept based on angiographic circulation time.

Object: The cumulative experience worldwide indicates complete radiosurgical obliteration rates of brain arteriovenous malformations (AVMs) ranging from 35 to 90%. The purpose of this study was to propose a strategy to increase the obliteration rate for AVMs through the dynamic definition of the key target volume (KTV).

Methods: A prospective series of patients harboring an AVM was assessed using digital subtraction angiography in which a digital counter was used to measure the several stages of the frame-by-frame circulation time.

Stereotactic noninvasive volume measurement compared with geometric measurement for indications and evaluation of gamma knife treatment.

Object: Volume estimation is one of the most important criteria in the evaluation and follow up of radiosurgical treatments and outcomes; however, several limitations are involved in the calculation estimation of target volumes.

Methods: Retrospective and prospective studies were conducted to evaluate the efficacy of a new noninvasive stereotactic method when it is compared with geometric volume calculation of intracranial tumors for planning stereotactic radiosurgery treatment as well as for follow up and outcome evaluation. Two equations were created that permit comparison of the calculated and measured volumes.

Phakic posterior chamber intraocular lens for high myopia.

Purpose: To evaluate the efficacy, predictability, stability, and safety of the surgical correction of high myopia using a phakic posterior chamber intraocular lens (PPC IOL).

Setting: Centro Oftalmológico de Valencia-CEOVAL, Valencia, Venezuela.

Methods: A retrospective study was performed to analyze 18 eyes of 12 patients who had implantation of a modified PPC IOL, the implantable contact lens (ICL), for the treatment of high myopia.

kDNA markers define two major Trypanosoma rangeli lineages in Latin-America.

Trypanosoma rangeli is a hemoflagellate parasite of man, domestic and wild animals in Central and South America. The genus Rhodnius is particularly susceptible to infection by T. rangeli and transmission by salivary inoculation has been demonstrated in 12 of 14 nominal species of naturally and experimentally infected insects.