Aerosol and Surface Stability of SARS-CoV-2 In this research letter, investigators report on the stability of SARS-CoV-2 and SARS-CoV-1 under experimental conditions. The viability of the two virus...

https://www.nejm.org/doi/pdf/10.1056/NEJMc2004973?articleTools=true

Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1.

SARS-CoV-2 Viral Load in Upper Respiratory Specimens The authors report results of an analysis of nasal and throat swabs from 17 patients in Zhuhai, China, who had received a diagnosis of Covid-19....

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SARS-CoV-2 Viral Load in Upper Respiratory Specimens of Infected Patients.

Three dimensional topologically massive gravity (TMG) with a negative cosmological constant ???2 and positive Newton constant G admits an AdS3 vacuum solution for any value of the graviton mass ? These are all known to be perturbatively unstable except at the recently explored chiral point ?? = 1 However we show herein that for every value of ?? ? 3 there are two other (potentially stable) vacuum solutions given by SL(2,) ? U(1)-invariant warped AdS3 geometries, with a timelike or spacelike U(1) isometry Critical behavior occurs at ?? = 3, where the warping transitions from a stretching to a squashing, and there are a pair of warped solutions with a null U(1) isometry For 3$>?? > 3, there are known warped black hole solutions which are asymptotic to warped AdS3 We show that these black holes are discrete quotients of warped AdS3 just as BTZ black holes are discrete quotients of ordinary AdS3 Moreover new solutions of this type, relevant to any theory with warped AdS3 solutions, are exhibited Finally we note that the black hole thermodynamics is consistent with the hypothesis that, for 3$>?? > 3, the warped AdS3 ground state of TMG is holographically dual to a 2D boundary CFT with central charges and 

/pdf/warped-ads-3-black-holes-2i3qvhrs8y.pdf

Warped $AdS_3$ Black Holes

We present a first-principles derivation of the main results of the Kerr/CFT correspondence and its extensions using only tools from gravity and quantum field theory, filling a few gaps in the literature when necessary. Firstly, we review properties of extremal black holes that imply, according to semi-classical quantization rules, that their near-horizon quantum states form a centrally-extended representation of the one-dimensional conformal group. This motivates the conjecture that the extremal Kerr and Reissner-Nordstrom black holes are dual to the chiral limit of a two-dimensional CFT. We also motivate the existence of an SL(2, ℤ) family of two-dimensional CFTs, which describe in their chiral limit the extremal Kerr-Newman black hole. We present generalizations in anti-de Sitter spacetime and discuss other matter-coupling and higher-derivative corrections. Secondly, we show how a near-chiral limit of these CFTs reproduces the dynamics of near-superradiant probes around near-extremal black holes in the semi-classical limit. Thirdly, we review how the hidden conformal symmetries of asymptotically-flat black holes away from extremality, combined with their properties at extremality, allow for a microscopic accounting of the entropy of non-extremal asymptotically-flat rotating or charged black holes. We conclude with a list of open problems.

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The Kerr/CFT Correspondence and its Extensions

We study weakly coupled U(1) theories in AdS3, their associated charged BTZ solutions, and their charged spectra. We find that modular invariance of the holographic dual two-dimensional CFT and compactness of the gauge group together imply the existence of charged operators with conformal dimension significantly below the black hole threshold. We regard this as a form of the Weak Gravity Conjecture (WGC) in three dimensions. We also explore the constraints posed by modular invariance on a particular discrete ℤ
 N
 symmetry which arises in our discussion. In this case, modular invariance does not guarantee the existence of light ℤ
 N
 -charged states. We also highlight the differences between our discussion and the usual heuristic arguments for the WGC based on black hole remnants.

/pdf/the-weak-gravity-conjecture-in-three-dimensions-1whhnsa8gd.pdf

The Weak Gravity Conjecture in three dimensions

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.

/pdf/2-1-dimensional-charged-black-hole-in-topologically-massive-3liompegw7.pdf

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

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.

https://journals.sagepub.com/doi/pdf/10.1177/2473974X20934734

Protection for Otolaryngologic Surgery in the COVID-19 Pandemic

We prove that the AdS/CFT calculation of 1-point functions can be drastically simplified by using variational arguments. We give a simple proof, valid for any theory that can be derived from a Lagrangian, that the large radius divergencies in 1-point functions can always be renormalized away (at least in the semiclassical approximation). The renormalized 1-point functions then follow by a simple variational problem involving only finite quantities. Several examples, a massive scalar, gravity, and renormalization flows, are discussed. Our results are general and can thus be used for dualities beyond AdS/CFT.

Tomás Andrade

Papers

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

Protection for Otolaryngologic Surgery in the COVID-19 Pandemic

Variational methods in AdS/CFT correspondence