Globular cluster metallicities and distances from disentangling their RR Lyrae light curves

We present mean horizontal branch absolute magnitudes and iron abundances for a sample of 39 globular clusters. These quantities were calculated in an unprecedented homogeneous fashion based on Fourier decomposition of ligt curves of RR Lyrae cluster members. Zero points for the luminosity calibrations are discussed. Our photometrically derived metallicities and distances compare very well with spectroscopic determinations of [Fe/H] and accurate distances obtained using {\sl Gaia} and {\sl Hubble Space Telescope} data. The need to distinguish between the results for RRab and RRc stars for a correct evaluation of the $M_V$--[Fe/H] relation is discussed. For RRab stars, the relation is non-linear, and the horizontal branch structure plays a significant role. For RRc stars, the relation remains linear and tight, and the slope is very shallow. Hence, the RRc stars seem better indicators of the parental cluster distances. Systematic time-series CCD imaging performed over the last 20 years enabled to discover and classify 330 variables in our sample of globular clusters.Comment: 21 pages, 5 Figures, 3 Tables. In pres

Optimality of a Network Monitoring Agent and Validation in a Real Probe

The evolution of commodity hardware makes it possible to use this type of equipment to implement traffic monitoring systems. A preliminary empirical evaluation of a network traffic probe based on Linux indicates that the system performance has significant losses as the network rate increases. To assess this issue, we consider a model with two tandem queues and a moving server. In this system, we formulate a three-dimensional Markov Decision Process in continuous time. The goal of the proposed model is to determine the position of the server in each time slot so as to optimize the system performance which is measured in terms of throughput. We first formulate an equivalent discrete-time Markov Decision Process and we propose a numerical method to characterize the solution of our problem in a general setting. The solution we obtain in this problem has been tested for a wide range of scenarios and, in all the instances, we observe that the optimality is close to a threshold type policy. We also consider a real probe and we validate the good performance of threshold policies in real applications.This research was partially supported by the Department of Education of the Basque Government, Spain through the Consolidated Research Groups NQaS (IT1635-22) and MATHMODE (IT1456-22), by the Marie Sklodowska-Curie, Spain grant agreement No 777778, by the Spanish Ministry of Science and Innovation, Spain with reference PID2019-108111RB-I00 (FEDER/AEI), by grant PID2020-117876RB-I00 funded by MCIN/AEI (10.13039/501100011033) and by Grant KK-2021/00026 funded by the Basque Government

Bacterial outer membrane vesicles and vaccine applications

Vaccines based on outer membrane vesicles (OMV) were developed more than 20 years ago against Neisseria meningitidis serogroup B. These nano-sized structures exhibit remarkable potential for immunomodulation of immune responses and delivery of “self” meningococcal antigens or unrelated antigens incorporated into the vesicle structure. This paper reviews different applications in OMV Research and Development (R&D) and provides examples of OMV developed and evaluated at the Finlay Institute in Cuba. A Good Manufacturing Practice (GMP) process was developed at the Finlay Institute to produce OMV from N. meningitidis serogroup B (dOMVB) using detergent extraction. Subsequently, OMV from N. meningitidis, serogroup A (dOMVA), serogroup W (dOMVW) and serogroup X (dOMVX) were obtained using this process. More recently, the extraction process has also been applied effectively for obtaining OMV on a research scale from Vibrio cholerae (dOMVC), Bordetella pertussis (dOMVBP), Mycobacterium smegmatis (dOMVSM) and BCG (dOMVBCG). The immunogenicity of the OMV have been evaluated for specific antibody induction, and together with functional bactericidal and challenge assays in mice have shown their protective potential. dOMVB has been evaluated with non-self neisserial antigens, including with a herpes virus type 2 glycoprotein, ovalbumin and allergens. In conclusion, OMV are proving to be more versatile than first conceived and remain an important technology for development of vaccine candidates. - See more at: http://journal.frontiersin.org/Journal/10.3389/fimmu.2014.00121/abstract#sthash.MwqUyZQ1.dpu

Modelo de colas con vacations aplicado a un sistema de captura de paquetes

[ES] La mejora de sistemas de captura de paquetes de red ha sido extensamente cubierta como tema de investigación en los pasados años. La mayoría de estas iniciativas han sido respaldadas por evaluaciones experimentales; sin embargo, ha habido pocas propuestas de modelado. Este trabajo presenta el modelado y el análisis de un sistema de cola finito con vacations aplicado a la etapa de captura de paquetes de un sistema de monitorización de red. Se plantean dos modelos con disciplina de servicio diferente (exhaustiva y limitada) y se evalúan sus rendimientos, principalmente en forma de throughput de captura, para distintos escenarios. Éstos contemplan diferentes tasas de entrada de paquetes y tiempos de vacation. Los resultados teóricos, derivados de un estudio analítico basado en ecuaciones de balance y su desarrollo en forma matricial, también son comparados con los de una sonda real de tráfico de red que captura paquetes.Zabala, L.; Ferro, A.; Nieva, A. (2018). Modelo de colas con vacations aplicado a un sistema de captura de paquetes. En XIII Jornadas de Ingeniería telemática (JITEL 2017). Libro de actas. Editorial Universitat Politècnica de València. 132-139. https://doi.org/10.4995/JITEL2017.2017.6580OCS13213

New Isothermic surfaces in S3

In this paper, we consider a method of constructing isothermic surfaces in S3 based on Ribaucour transformations. By applying the theory to the flat torus, we obtain two family of complete isothermic surfaces in S3. One four-parameter family of complete isothermic surfaces that contains n-bubble surfaces inside and outside of the torus. We also get another four-parameter of complete isothermic surfaces which are Dupin surfaces. As aplication we obtain explicit solutions of the Calapso equation