Scalar field dynamics in a BTZ background with generic boundary conditions

The revisit the dynamics of a massive scalar field in a BTZ background taking into account the lack of global hyperbolicity of the spacetime. We approach this issue using the strategy of Ishibashi and Wald which finds a unique smooth solution as the causal evolution of initial data, each possible evolution corresponding to a positive self-adjoint extension of certain operator in a Hilbert space on the initial surface. Moreover, solutions obtained this way are the most general ones satisfying a few physically-sensible requirements. This procedure is intimately related to the choice of boundary conditions and the existence of bound states. We find that the scalar field dynamics in the (effective) mass window −3/4≤m2eℓ2<0 can be well-defined within a one-parametric family of distinct boundary conditions (−3/4 being the conformally-coupled case), while for m2eℓ2≥0 the boundary condition is unique (only one self-adjoint extension is possible). It is argued that there is no sensible evolution possible for m2eℓ2<−1, and also shown that in the range m2eℓ2∈[−1,−3/4) there is a U(1) family of allowed boundary conditions, however, the positivity of the self-adjoint extensions is only motivated but not proven. We focus mainly in describing the dynamics of such evolutions given the initial data and all possible boundary conditions, and in particular we show the energy is always positive and conserved.Fil: Garbarz, Alan Nicolás. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: La Madrid, Joan. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Leston, Mauricio. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin

Comments on the two-point string amplitudes

The two-point string amplitude at tree level in flat spacetime reproduces the expected expression for free particles. This has been proven by Erbin, Maldacena and Skliros in [JHEP 07 (2019) 139] by two methods. Here, we provide an alternative proof of this result. Our method consists in considering a timelike Liouville direction as a regularization parameter, which suffices to break time translation invariance and, at the same time, to stabilize the residual conformal symmetry in the worldsheet. This allows taking a limit and restoring Poincare symmetry in a controlled way, thus reproducing the correct expression of the two-point amplitude.Comment: 12 page

Axion minima in string theory

We study the landscape of axion theories in compactifications of type IIB string theory on orientifolds of Calabi-Yau threefolds. In a sample of approximately 400,000 geometries we find that in the regime of perturbative control there are only a handful of distinct axion minima per geometry, despite there being infinitely many instanton contributions to the potential with unbounded charges. The ensemble we consider has numbers of axion fields ranging from 1 to 491, but the median number of distinct minima is 1, the mean number is 1.9 and the largest is 54. These small numbers of minima occur because the leading axion charge matrix is quite sparse, while the subleading corrections are increasingly exponentially suppressed as the charges increase. On their own, such potentials are nowhere near rich enough to be of interest anthropically. This is in stark contrast to potentials for which the charge matrix is less sparse or the hierarchies between the instanton contributions are less steep, where one can find $\mathcal{O}(10^{500})$ minima for $\mathcal{O}(500)$ axions. To generate a sufficiently large landscape from string compactifications our results indicate that one would need to rely on varying flux or topology, or to develop tools that allow one to go beyond the regime we can control with current techniques.Comment: 14+6 pages, 1 figur

Use of 3D Prototypes for Complex Surgical Oncologic Cases

Introduction: Physical 3D models known by the industry as rapid prototyping involve the creation of a physical model from a 3D computer version. In recent years, there has been an increasing number of reports on the use of 3D models in medicine. Printing such 3D models with different materials integrating the many components of human anatomy is technically challenging. In this article, we report our technological developments along with our clinical implementation experience using high-fidelity 3D prototypes of tumors encasing major vessels in anatomically sensitive areas. Methods: Three patients with tumors encasing major vessels that implied complex surgery were selected for surgical planning using 3D prototypes. 3D virtual models were obtained from routine CT and MRI images. The models, with all their anatomical relations, were created by an expert pediatric radiologist and a surgeon, image by image, along with a computerized-aided design engineer. Results: Surgeons had the opportunity to practice on the model before the surgery. This allowed questions regarding surgical approach; feasibility and potential complications to be raised in advance of the actual procedure. All patients then successfully underwent surgery as planned. Conclusion: Having a tumor physically printed in its different main component parts with its anatomical relationships is technically feasible. Since a gross total resection is prognostic in a significant percentage of tumor types, refinements in planning may help achieve greater and safer resections therefore contributing to improve surgical management of complex tumors. In this early experience, 3D prototyping helped significantly in the many aspects of surgical oncology planning

Determinacions del perfil genètic del càncer pediàtric

Oncologia; Perfil genètic; Càncer pediàtric; PrecisióOncología; Perfil genético; Cáncer pediátrico; PrecisiónOncology; Genetic profile; Pediatric cancer; AccuracyL'àmbit d'aquest grup de treball és la implementació de panels NGS per a diagnòstic / pronòstic / tractament de càncer en pacients menors de 18 anys (oncologia i hematologia). Els casos de predisposició genètica en pacients pediàtrics es tractaran en el grup de predisposició genètica. El càncer infantil comprèn més de 40 entitats entre leucèmies, limfomes, tumors cerebrals i sòlids extracranials; per la qual cosa no és possible tècnicament o operativament fer panels específics per a cada un d'aquests càncers. Serà necessari utilitzar panels comercials o acadèmics dissenyats específicament per a càncer infantil

Determinacions del perfil genètic del càncer pediàtric

Oncologia; Perfil genètic; Càncer pediàtric; PrecisióOncología; Perfil genético; Cáncer pediátrico; PrecisiónOncology; Genetic profile; Pediatric cancer; AccuracyL'àmbit d'aquest grup de treball és la implementació de panels NGS per a diagnòstic / pronòstic / tractament de càncer en pacients menors de 18 anys (oncologia i hematologia). Els casos de predisposició genètica en pacients pediàtrics es tractaran en el grup de predisposició genètica. El càncer infantil comprèn més de 40 entitats entre leucèmies, limfomes, tumors cerebrals i sòlids extracranials; per la qual cosa no és possible tècnicament o operativament fer panels específics per a cada un d'aquests càncers. Serà necessari utilitzar panels comercials o acadèmics dissenyats específicament per a càncer infantil

Epigenetic loss of RNA‑methyltransferase NSUN5 in glioma targets ribosomes to drive stress adaptive translational program

Tumors have aberrant proteomes that often do not match their corresponding transcriptome profiles. One possible cause of this discrepancy is the existence of aberrant RNA modification landscapes in the so-called epitranscriptome. Here, we report that human glioma cells undergo DNA methylation-associated epigenetic silencing of NSUN5, a candidate RNA methyltransferase for 5-methylcytosine. In this setting, NSUN5 exhibits tumor-suppressor characteristics in vivo glioma models. We also found that NSUN5 loss generates an unmethylated status at the C3782 position of 28S rRNA that drives an overall depletion of protein synthesis, and leads to the emergence of an adaptive translational program for survival under conditions of cellular stress. Interestingly, NSUN5 epigenetic inactivation also renders these gliomas sensitive to bioactivatable substrates of the stress-related enzyme NQO1. Most importantly, NSUN5 epigenetic inactivation is a hallmark of glioma patients with long-term survival for this otherwise devastating disease

Treatment with tocilizumab or corticosteroids for COVID-19 patients with hyperinflammatory state: a multicentre cohort study (SAM-COVID-19)

Objectives: The objective of this study was to estimate the association between tocilizumab or corticosteroids and the risk of intubation or death in patients with coronavirus disease 19 (COVID-19) with a hyperinflammatory state according to clinical and laboratory parameters. Methods: A cohort study was performed in 60 Spanish hospitals including 778 patients with COVID-19 and clinical and laboratory data indicative of a hyperinflammatory state. Treatment was mainly with tocilizumab, an intermediate-high dose of corticosteroids (IHDC), a pulse dose of corticosteroids (PDC), combination therapy, or no treatment. Primary outcome was intubation or death; follow-up was 21 days. Propensity score-adjusted estimations using Cox regression (logistic regression if needed) were calculated. Propensity scores were used as confounders, matching variables and for the inverse probability of treatment weights (IPTWs). Results: In all, 88, 117, 78 and 151 patients treated with tocilizumab, IHDC, PDC, and combination therapy, respectively, were compared with 344 untreated patients. The primary endpoint occurred in 10 (11.4%), 27 (23.1%), 12 (15.4%), 40 (25.6%) and 69 (21.1%), respectively. The IPTW-based hazard ratios (odds ratio for combination therapy) for the primary endpoint were 0.32 (95%CI 0.22-0.47; p < 0.001) for tocilizumab, 0.82 (0.71-1.30; p 0.82) for IHDC, 0.61 (0.43-0.86; p 0.006) for PDC, and 1.17 (0.86-1.58; p 0.30) for combination therapy. Other applications of the propensity score provided similar results, but were not significant for PDC. Tocilizumab was also associated with lower hazard of death alone in IPTW analysis (0.07; 0.02-0.17; p < 0.001). Conclusions: Tocilizumab might be useful in COVID-19 patients with a hyperinflammatory state and should be prioritized for randomized trials in this situatio

Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic

This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic

MUSiC : a model-unspecific search for new physics in proton-proton collisions at root s=13TeV

Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.Peer reviewe