The geometry of null rotation identifications

The geometry of flat spacetime modded out by a null rotation (boost+rotation) is analysed. When embedding this quotient spacetime in String/M-theory, it still preserves one half of the original supersymmetries. Its connection with the BTZ black hole, supersymmetric dilatonic waves and one possible resolution of its singularity in terms of nullbranes are also discussed.Comment: 1+18 pages, 5 figures. v2 references adde

Direct evidende of sex and a hypothesis about meiosis in Symbiodiniaceae

Dinoflagellates in the family Symbiodiniaceae are obligate endosymbionts of diverse marine invertebrates, including corals, and impact the capacity of their hosts to respond to climate change-driven ocean warming. Understanding the conditions under which increased genetic variation in Symbiodiniaceae arises via sexual recombination can support efforts to evolve thermal tolerance in these symbionts and ultimately mitigate coral bleaching, the breakdown of the coral-Symbiodiniaceae partnership under stress. However, direct observations of meiosis in Symbiodiniaceae have not been reported, despite various lines of indirect evidence that it occurs. We present the first cytological evidence of sex in Symbiodiniaceae based on nuclear DNA content and morphology using Image Flow Cytometry, Cell Sorting and Confocal Microscopy. We show the Symbiodiniaceae species, Cladocopium latusorum, undergoes gamete conjugation, zygote formation, and meiosis within a dominant reef-building coral in situ. On average, sex was detected in 1.5% of the cells analyzed (N = 10,000–40,000 cells observed per sample in a total of 20 samples obtained from 3 Pocillopora colonies). We hypothesize that meiosis follows a two-step process described in other dinoflagellates, in which diploid zygotes form dyads during meiosis I, and triads and tetrads as final products of meiosis II. This study sets the stage for investigating environmental triggers of Symbiodiniaceae sexuality and can accelerate the assisted evolution of a key coral symbiont in order to combat reef degradation

Decay Modes of Intersecting Fluxbranes

Just as the single fluxbrane is quantum mechanically unstable to the nucleation of a locally charged spherical brane, so intersecting fluxbranes are unstable to various decay modes. Each individual element of the intersection can decay via the nucleation of a spherical brane, but uncharged spheres can also be nucleated in the region of intersection. For special values of the fluxes, however, intersecting fluxbranes are supersymmetric, and so are expected to be stable. We explicitly consider the instanton describing the decay modes of the two--element intersection (an F5-brane in the string theory context), and show that in dimensions greater than four the action for the decay mode of the supersymmetric intersection diverges. This observation allows us to show that stable intersecting fluxbranes should also exist in type 0A string theory.Comment: 19 pages, 6 figures. References adde

Quotients of AdS_{p+1} x S^q: causally well-behaved spaces and black holes

Starting from the recent classification of quotients of Freund--Rubin backgrounds in string theory of the type AdS_{p+1} x S^q by one-parameter subgroups of isometries, we investigate the physical interpretation of the associated quotients by discrete cyclic subgroups. We establish which quotients have well-behaved causal structures, and of those containing closed timelike curves, which have interpretations as black holes. We explain the relation to previous investigations of quotients of asymptotically flat spacetimes and plane waves, of black holes in AdS and of Godel-type universes.Comment: 48 pages; v2: minor typos correcte

Clinical-decision criteria to identify recurrent diabetic macular edema patients suitable for fluocinolone acetonide implant therapy (Iluvien®) and follow-up considerations/ recommendations

Current management of diabetic macular edema (DME) predominantly involves treatment with short-acting intravitreal injections of anti-vascular endothelial growth factors (anti-VEGFs) and/or corticosteroids; however, short-acting therapies (lasting between 1 and 6 months) require frequent injections to maintain efficacy, meaning a considerable treatment burden for diabetic patients with multiple comorbidities. Continuous injections needed in some cases are an economic burden for patients/healthcare system, so real-life clinical practice tends to adopt a reactive approach, ie, watch and wait for worsening symptoms, which consequently increases the risk of undertreatment and edema recurrence. On March 7th 2019, a group of experts in retinal medicine and surgery held a roundtable meeting in Madrid, Spain to discuss how to (1) optimize clinical outcomes through earlier use of fluocinolone acetonide (FAc) implant (ILUVIEN®) in patients with persistent or recurrent DME despite therapy; and, (2) to provide guidance to assist physicians in deciding which patients should be treated with ILUVIEN. In this regard, a 36-month follow-up consensus protocol is presented. In conclusion, patients that achieve a complete or partial anatomical, and preferably functional, response following one or two intravitreal dexametha-sone implants, but with recurrence of edema after 3–4 months, are deemed by the authors most likely to benefit from ILUVIEN, and the switch to FAc implant should not be delayed more than 12 months after the initiation of at least the first dexamethasone implant

Dualities, Twists, and Gauge Theories with Non-Constant Non-Commutativity

We study the world volume theory of D3-branes wrapping the Melvin universe supported by background NSNS B-field. In the appropriate decoupling limit, the open string dynamics is that of non-commutative guage field theory with non-constant non-commutativity. We identify this model as a simple Melvin twist of flat D3 branes. Along similar lines, one recognizes the model of Hashimoto and Sethi as being the Melvin null twist, and the model of Dolan and Nappi as being the null Melvin twist, of the flat D3-brane. This construction therefore offers a unified perspective on most of the known explicit constructions of non-commutative gauge theories as a decoupled theory of D-branes in a B-field background. We also describe the world volume theory on the D3-brane in Melvin universe which is decaying via the nucleation of monopole anti-monopole pair.Comment: 18 pages, 1 figure, References added, typo correcte

Twisted Backgrounds, PP-Waves and Nonlocal Field Theories

We study partially supersymmetric plane-wave like deformations of string theories and M-theory on brane backgrounds. These deformations are dual to nonlocal field theories. We calculate various expectation values of configurations of closed as well as open Wilson loops and Wilson surfaces in those theories. We also discuss the manifestation of the nonlocality structure in the supergravity backgrounds. A plane-wave like deformation of little string theory has also been studied.Comment: 46 pages, changed to JHEP forma

Efecto de quitosano en el crecimiento in vitro de Thecaphora frezii

Este biopolímero no es tóxico para mamíferos y animales superiores, y estimula la respuesta de defensa de las plantas frente a estrés biótico y abiótico. Desde que Allan y Hadwiger en 1979, mostraron por primera vez el efecto antifúngico de quitosano, este biopolímero ha atraído la atención de numerosos investigadores con el propósito de evaluar la sensibilidad de diferentes hongos frente a este compuesto. Se ha visto que quitosano de bajo peso molecular y alto grado de deacetilación es más efectivo para inhibir el crecimiento de hongos patógenos. El objetivo del presente trabajo fue analizar el efecto de quitosano como inhibidor del crecimiento in vitro del hongo Thecaphora frezii, agente causal de la enfermedad del carbón del maní.Instituto de Patología VegetalFil: Merino, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Unidad de Fitopatología y Modelización Agrícola (UFYMA); Argentina.Fil: Paccioretti, Mauro Andres. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas(CONICET). Unidad de Fitopatología y Modelización Agrícola (UFYMA). Córdoba; Argentina.Fil: Díaz, M.S. Gobierno de Córdoba. Ministerio de Ciencia y Tecnología. Centro de excelencia en productos y procesos Córdoba (CEPROCOR); ArgentinaFil: Figueroa, A.C. Gobierno de Córdoba. Ministerio de Ciencia y Tecnología. Centro de excelencia en productos y procesos Córdoba (CEPROCOR); ArgentinaFil: Paredes, Juan Andrés. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Fitopatología y Modelización Agrícola (UFYMA); Argentina.Fil: Rago, Alejandro Mario. Instituto Nacional de Tecnología Agropecuaria (INTA). Centro de Investigaciones Agropecuarias; Argentin

Manifestations of intraocular inflammation over time in patients on brolucizumab for neovascular AMD

Purpose To describe the adverse events associated with brolucizumab, in particular the sequence of intraocular inflammation (IOI), retinal vasculitis (RV), and/or retinal vascular occlusion (RO).Methods This was an unmasked post hoc analysis of the randomized HAWK/HARRIER clinical trials. Patients with neovascular AMD in the brolucizumab arms of the trials were included. IOI-related adverse events reported by study investigators were analyzed to determine early signs and the time course of IOI-related adverse events, using a subgroup of patients with definite/probable IOI cases identified in an independent unmasked post hoc review by an external safety review committee. A limited literature review on MI following anti-VEGF therapy was also conducted.Results Among 50 patients with definite/probable IOI cases identified by the safety review committee, 12 had RV or RO adverse events reported by the investigators. For 6 of 12, IOI (other than RV) was reported before RV or RO. The duration from the first IOI adverse event to the first RV or RO adverse event ranged from 16 to 171 days for 5 patients and was 553 days for 1 patient. Four of the 6 patients received >= 1 brolucizumab injection on or after the date of the first IOI adverse event and before the first RV or RO adverse event.Conclusions IOI may precede RV or RO in some patients treated with brolucizumab.Ophthalmic researc

(Twisted) Toroidal Compactification of pp-Waves

The maximally supersymmetric type IIB pp-wave is compactified on spatial circles, with and without an auxiliary rotational twist. All spatial circles of constant radius are identified. Without the twist, an S$^1$ compactification can preserve 24, 20 or 16 supercharges. $T^2$ compactifications can preserve 20, 18 or 16 supercharges; $T^3$ compactifications can preserve 18 or 16 supercharges and higher compactifications preserve 16 supercharges. The worldsheet theory of this background is discussed. The T-dual and decompactified type IIA and M-theoretic solutions which preserve 24 supercharges are given. Some comments are made regarding the AdS parent and the CFT description.Comment: 22 pages REVTeX 4 and AMSLaTeX. v3: References and a paragraph on nine dimensional Killing spinors were added. v4: A few typos corrected and a footnote was modifie