Long-term Stellar Variability in the Galactic Centre Region

© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.We report the detection of variable stars within a 11.5' x 11.5' region near the Galactic centre (GC) that includes the Arches and Quintuplet clusters, as revealed by the VISTA Variables in the Via Lactea (VVV) survey. There are 353 sources that show Ks-band variability, of which the large majority (81%) correspond to red giant stars, mostly in the asymptotic giant branch (AGB) phase. We analyze a population of 52 red giants with long-term trends that cannot be classified into the typical pulsating star categories. Distances and extinctions are calculated for 9 Mira variables, and we discuss the impact of the chosen extinction law on the derived distances. We also report the presence of 48 new identified young stellar object (YSO) candidates in the region.Peer reviewe

Reconfigurable optical multiplexer based on liquid crystals for polymer optical fiber networks

In this work, different novel 3×1 multiplexer structures for being used in polymer optical fiber networks are proposed. Designs are compact, scalable, and of low consumption, capable of operating in a large wavelength range simultaneously 660, 850, and 1300 nm, due to the use of nematic liquid crystal cells. Light that comes from each input port is handled independently and eight operation modes are possible. Control electronics has been made using a programmable integrated circuit. Electronic system makes available the managing of the optical stage using a computer. An additional four optical sensors have been included for allowing the optical status checking. Finally, a polarization independent multiplexer has been implemented and tested. Insertion losses less than 4 dB and isolation better than 23 dB have been measured. In addition, 30-ms and 15-ms setup and rise times have been obtained. The proposed multiplexer can be used in any polymer optical fiber network, even in perfluorinated graded index one, and it can be specially useful in optical sensor networks, or in coarse wavelength division multiplexing networks.Publicad

Modal liquid crystal temperature sensor

Proceeding of: 2014 IEEE SENSORS proceedings: Valencia, Spain, November 2-5, 2014.In this work, a novel liquid crystal temperature sensor is proposed. This sensor is composed by only two electrodes. A simple and easily scalable structure uses the temperature dependence of the liquid crystal permittivity as the sensing magnitude. The sensor has a high sensitivity, low voltage control, low power consumption and high linearity. The analytical modelling allows an optimization of the structure, in terms of sensitivity. Several liquid crystal has been investigated. The response improves the characteristics of previous LC sensors and even some commercial sensors (e.g. 60 mV/°C for 10 V rms of applied voltage, six times more than of most silicon temperature sensors).This work was supported in part by the Ministerio de Ciencia e Innovación of Spain (grant no.TEC2009-13991-C02-01) and the Comunidad de Madrid (grant no. FACTOTEM2 S2009/ESP-1781)

Modelling and electro-optical testing of suspended particle devices

Some smart windows make use of suspended particle devices (SPDs) which are made of charged rod-shape particles that change their orientation in an applied electric field, thereby allowing transmittance control. In this work, the electro-optical behaviour of a commercial SPD is analyzed. Impedance analysis shows characteristics similar to those of a Randles circuit, and a modified equivalent circuit is proposed and experimentally validated. Intermediate levels of transmittance are obtained using a customized field programmable gate array (FPGA)-based electrical circuit. Finally, measurements are taken to check the applicability of the SPD device and control system in smart glazing or photonic applications.Universidad Carlos III de MadridThis research was partially supported by funds from the Spanish Ministry of Science and Technology (Project PTR95-0940.01.OP), and by Comunidad de Madrid (Project FACTOTEMCM:S-0505/ESP/000417).Publicad

Development of Thiophene Compounds as Potent Chemotherapies for the Treatment of Cutaneous Leishmaniasis Caused by Leishmania major

Leishmania major (L. major) is a protozoan parasite that causes cutaneous leishmaniasis. About 12 million people are currently infected with an annual incidence of 1.3 million cases. The purpose of this study was to synthesize a small library of novel thiophene derivatives, and evaluate its parasitic activity, and potential mechanism of action (MOA). We developed a structure–activity relationship (SAR) study of the thiophene molecule 5A. Overall, eight thiophene derivatives of 5A were synthesized and purified by silica gel column chromatography. Of these eight analogs, the molecule 5D showed the highest in vitro activity against Leishmania major promastigotes (EC50 0.09 ± 0.02 µM), with an inhibition of the proliferation of intracellular amastigotes higher than 75% at only 0.63 µM and an excellent selective index. Moreover, the effect of 5D on L. major promastigotes was associated with generation of reactive oxygen species (ROS), and in silico docking studies suggested that 5D may play a role in inhibiting trypanothione reductase. In summary, the combined SAR study and the in vitro evaluation of 5A derivatives allowed the identification of the novel molecule 5D, which exhibited potent in vitro anti-leishmanial activity resulting in ROS production leading to cell death with no significant cytotoxicity towards mammalian cells

La antropología en la planificación regional como elemento para la gestión integrada de recursos hídricos

Aquí se considera que los escritos de Ángel Palerm sobre Planificación, son una excelente herramienta de introducción a la Gestión Integrada de los Recursos Hídricos (GIRH). De allí que el objetivo de este trabajo sea la revisión e identificación de las principales propuestas palermianas sobre los conceptos y herramientas de cómo llevar a cabo la planificación y el desarrollo, con el fi n de presentarlos como una introducción y reflexión a la gestión integrada de los recursos hídricos (GIRH). Para lograrlo, se analiza el material y los documentos reunidos y publicados de Ángel Palerm sobre el tema, que datan desde 1950 hasta 1980, ordenando los casos, los conceptos, las herramientas y las formas metodológicas que Palerm utilizó para la planificación

Trends and factors related to adolescent pregnancies: an incidence trend and conditional inference trees analysis of northern Nicaragua demographic surveillance data

Background We aimed to identify the 2001-2013 incidence trend, and characteristics associated with adolescent pregnancies reported by 20-24-year-old women. Methods A retrospective analysis of the Cuatro Santos Northern Nicaragua Health and Demographic Surveillance 2004-2014 data on women aged 15-19 and 20-24. To calculate adolescent birth and pregnancy rates, we used the first live birth at ages 10-14 and 15-19 years reported by women aged 15-19 and 20-24 years, respectively, along with estimates of annual incidence rates reported by women aged 20-24 years. We conducted conditional inference tree analyses using 52 variables to identify characteristics associated with adolescent pregnancies. Results The number of first live births reported by women aged 20-24 years was 361 during the study period. Adolescent pregnancies and live births decreased from 2004 to 2009 and thereafter increased up to 2014. The adolescent pregnancy incidence (persons-years) trend dropped from 2001 (75.1 per 1000) to 2007 (27.2 per 1000), followed by a steep upward trend from 2007 to 2008 (19.1 per 1000) that increased in 2013 (26.5 per 1000). Associated factors with adolescent pregnancy were living in low-education households, where most adults in the household were working, and high proportion of adolescent pregnancies in the local community. Wealth was not linked to teenage pregnancies. Conclusions Interventions to prevent adolescent pregnancy are imperative and must bear into account the context that influences the culture of early motherhood and lead to socioeconomic and health gains in resource-poor settings

The JCMT Transient Survey : Single Epoch Transients and Variability of Faint Sources

© 2022. The Author(s). Published by the American Astronomical Society. This is an open access article distributed under the Creative Commons Attribution License, to view a copy of the license, see: https://creativecommons.org/licenses/by/4.0/Short-duration flares at millimeter wavelengths provide unique insights into the strongest magnetic reconnection events in stellar coronae, and combine with longer-term variability to introduce complications to next-generation cosmology surveys. We analyze 5.5 years of JCMT Transient Survey 850 micron submillimeter monitoring observations toward eight Gould Belt star-forming regions to search for evidence of transient events or long-duration variability from faint sources. The eight regions (30 arcmin diameter fields), including ~1200 infrared-selected YSOs, have been observed on average 47 times with integrations of approximately half an hour, or one day total spread over 5.5 years. Within this large data set, only two robust faint source detections are recovered: JW 566 in OMC 2/3 and MGM12 2864 in NGC 2023. JW 566, a Class II TTauri binary system previously identified as an extraordinary submillimeter flare, remains unique, the only clear single-epoch transient detection in this sample with a flare eight times bright than our ~4.5 sigma detection threshold of 55 mJy/beam. The lack of additional recovered flares intermediate between JW 566 and our detection limit is puzzling, if smaller events are more common than larger events. In contrast, the other submillimeter variable identified in our analysis, Source 2864, is highly variable on all observed timescales. Although Source 2864 is occasionally classified as a YSO, the source is most likely a blazar. The degree of variability across the electromagnetic spectrum may be used to aid source classification.Peer reviewe