A Note on T-dualities in the Pure Spinor Heterotic String

In this note we study the preservation of the classical pure spinor BRST constraints under super T-duality transformations. We also determine the invariance of the one-loop conformal invariance and of the local gauge and Lorentz anomalies under the super T-dualities.Comment: References adde

One-loop conformal invariance of the type II pure spinor superstring in a curved background

Indexación: Scopus.We compute the one-loop beta functions for the Type II superstring using the pure spinor formalism in a generic supergravity background. It is known that the classical pure spinor BRST symmetry puts the background fields on-shell. In this paper we show that the one-loop beta functions vanish as a consequence of the classical BRST symmetry of the action.https://iopscience.iop.org/article/10.1088/1126-6708/2007/01/04

Phase diagram of silicon from atomistic simulations

In this letter we present a calculation of the temperature-pressure phase diagram of Si in a range of pressures covering from -5 to 20 GPa and temperatures up to the melting point. The phase boundaries and triple points between the diamond, liquid, $\beta$-Sn and ${Si}_{34}$ clathrate phases are reported. We have employed efficient simulation techniques to calculate free energies and to numerically integrate the Clausius-Clapeyron equation, combined with a tight binding model capable of an accuracy comparable to that of first-principles methods. The resulting phase diagram agrees well with the available experimental data.Comment: 5 pages, 1 figure, accepted in PR

Notes on beta-deformations of the pure spinor superstring in AdS(5) x S(5)

We study the properties of the vertex operator for the beta-deformation of the superstring in AdS(5) x S(5) in the pure spinor formalism. We discuss the action of supersymmetry on the infinitesimal beta-deformation, the application of the homological perturbation theory, and the relation between the worldsheet description and the spacetime supergravity description.Comment: LaTeX, 74pp

Who uses Transport Network Companies?: Characterization of Demand and its Relationship with Public Transit in Medellín

Transport Network Companies (TNCs) have become a popular alternative for mobility due to their ability to provide on-demand flexible mobility services. By offering smartphone-based, ride-hailing services capable of satisfying specific travel needs, these modes have transformed urban mobility worldwide. However, to-date, few studies have examined the impacts in the Latin American context. This analysis is a critical first step in developing policies to promote efficient and sustainable transport systems in the Latin-American region. This research examines the factors affecting the adoption of on-demand ride services in Medellín, Colombia. It also explores whether these are substituting or competing with public transit. First, it provides a descriptive analysis in which we relate the usage of platform-based services with neighborhood characteristics, socioeconomic information of individuals and families, and trip-level details. Next, factors contributing to the election of platform-based services modeled using discrete choice models. The results show that wealthy and highly educated families with low vehicle availability are more likely to use TNCs compared to other groups in Medellín. Evidence also points at gender effects, with being female significantly increasing the probability of using a TNC service. Finally, we observe both transit complementary and substitution patterns of use, depending on the context and by whom the service is requested

BRST Anomaly and Superspace Constraints of the Pure Spinor Heterotic String in a Curved Background

The pure spinor heterotic string in a generic super Yang-Mills and supergravity background is considered. We determine the one-loop BRST anomaly at the cohomological level. We prove that it can be absorbed by consistent corrections of the classical constraints due to Berkovits and Howe, in agreement with the Green-Schwarz cancelation mechanism.Comment: harvmac-big, 18 pages; references added; minor correction

Nivel de madurez y grado de satisfacción de las herramientas libres para pruebas funcionales

This work aims to provide information about some free tools to implement functional testing, from the perspective of organizational use as an alternative to other existing. We selected nine tools that were applied principles of selection and assessment oriented to find the level of maturity and degree of satisfaction. The selection process and the metrics applied are described in this literature review to the web.Este trabajo tiene como finalidad proporcionar información acerca de algunas herramientas libres para implementar pruebas funcionales, desde la perspectiva de su utilización organizacional y como una alternativa a otras existentes. Se seleccionaron nueve herramientas a las que se aplicaron principios de selección y valoración orientados a encontrar el nivel de madurez y el grado de satisfacción. El proceso de selección y las métricas aplicadas se describen en este estudio de revisión a la web

La girolline, nouvelle substance antitumorale extraite de l'éponge, Pseudaxinyssa cantharella n. sp. (Axinellidae)

Une nouvelle substance antitumorale a été isolée d'une Eponge néo-calédonienne, #Pseudaxinyssa cantharella$. Sa structure a été établie à l'aide de ses caractéristiques spectrales et par préparation de dérivés sélectivement substitués. (Résumé d'auteur