Abrupt transition from low-coherence to high-coherence radiation in a semiconductor laser with optical feedback

Semiconductor lasers are very sensitive to optical feedback. Although it is well known that coherent feedback lowers the threshold of the laser, the characteristics of the transition from low-coherence radiation—dominated by spontaneous emission—below threshold to high-coherence radiation—dominated by stimulated emission—above threshold have not yet been investigated. Here we show experimentally that, in contrast to the transition that occurs in the solitary laser, in the laser with feedback the transition to high-coherence emission can occur abruptly. We use the speckle technique to show that the transition varies from smooth to abrupt as the amount of light fed back to the laser increases.Peer ReviewedPostprint (published version

Experimental study of spatial and temporal coherence in a laser diode with optical feedback

© 2023 Optica Publishing Group. Users may use, reuse, and build upon the article, or use the article for text or data mining, so long as such uses are for non-commercial purposes and appropriate attribution is maintained. All other rights are reserved.Optical feedback can reduce the linewidth of a semiconductor laser by several orders of magnitude, but it can also cause line broadening. Although these effects on the temporal coherence of the laser are well known, a good understanding of the effects of feedback on the spatial coherence is still lacking. Here we present an experimental technique that allows discriminating the effects of feedback on temporal and spatial coherence of the laser beam. We analyze the output of a commercial edge-emitting laser diode, comparing the contrast of speckle images recorded using a multimode (MM) or single mode (SM) fiber and an optical diffuser, and also, comparing the optical spectra at the end of the MM or SM fiber. Optical spectra reveal feedback-induced line broadening, while speckle analyses reveal reduced spatial coherence due to feedback-excited spatial modes. These modes reduce the speckle contrast (SC) up to 50% when speckle images are recorded using the MM fiber, but do not affect the SC when the images are recorded using the SM fiber and diffuser, because the spatial modes that are excited by the feedback are filtered out by the SM fiber. This technique is generic and can be used to discriminate spatial and temporal coherence of other types of lasers and under other operating conditions that can induce a chaotic output.Institució Catalana de Recerca i Estudis Avançats (Academia); Agència de Gestió d’Ajuts Universitaris i de Recerca (2021 SGR 00606, FI Scholarship); Ministerio de Ciencia, Innovación y Universidades (PID2021-123994NBC21).Peer ReviewedPostprint (published version

Assessing competences in sustainability in teaching degrees and post-degrees: a proposal of a tool

Este estudio presenta una revisión de competencias genéricas en sostenibilidad (CS) en Educación Superior y proporciona una compilación de estas CS mediante una rúbrica que sirve como instrumento para evaluar el nivel de adquisición de las CS de los estudiantes universitarios en el campo de la educación. La rúbrica ha sido diseñada, analizada y contrastada por un grupo de investigadores de diferentes universidades vinculados al campo de la educación. Ha sido adaptada a los grados y posgrados de educación de ocho universidades y está estructurada en tres niveles de dominio en la adquisición de las competencias. Esta rúbrica puede ser un instrumento útil para la evaluación de la CS en los grados de educación del sistema universitario español.This study presents a review on the generic competences in sustainability (CS) at higher education and provides a compilation of these CS through a rubric that serves as a tool to assess the level of CS acquisition among university students of teacher training. The rubric has been designed, analysed and contrasted by a group of researchers from different universities linked to teacher training courses. It has been adapted to different undergraduate and postgraduate teaching programs at eight universities. It is structured in three levels of competency acquisition. This rubric can be a useful instrument for the assessment of CS in the degrees of education in the Spanish university system

Identification of non-coding genetic variants in samples from hypoxemic respiratory disease patients that affect the transcriptional response to hypoxia

A wide range of diseases course with an unbalance between the consumption of oxygen by tissues and its supply. This situation triggers a transcriptional response, mediated by the hypoxia inducible factors (HIFs), that aims to restore oxygen homeostasis. Little is known about the inter-individual variation in this response and its role in the progression of disease. Herein, we sought to identify common genetic variants mapping to hypoxia response elements (HREs) and characterize their effect on transcription. To this end, we constructed a list of genome-wide HIF-binding regions from publicly available experimental datasets and studied the genetic variability in these regions by targeted re-sequencing of genomic samples from 96 chronic obstructive pulmonary disease and 144 obstructive sleep apnea patients. This study identified 14 frequent variants disrupting potential HREs. The analysis of the genomic regions containing these variants by means of reporter assays revealed that variants rs1009329, rs6593210 and rs150921338 impaired the transcriptional response to hypoxia. Finally, using genome editing we confirmed the functional role of rs6593210 in the transcriptional regulation of EGFR. In summary, we found that inter-individual variability in non-coding regions affect the response to hypoxia and could potentially impact on the progression of pulmonary diseases.Ministerio de Ciencia e Innovación (Spanish Ministry of Science and Innovation, MICINN) [SAF2011 24225 to LdelP, SAF2014-53819-R to L.delP., B.J.]; Comunidad Autónoma de Madrid [S2010/BMD-2542 to L.delP., F.G.R., J.A.], Sociedad Española de Neumología y Cirugía Torácica (SEPAR) [34/2013 to LdelP, F.G.R.]; Fondo de Investigación Sanitaria/Instituto de Salud Carlos III [PI13-01512 to F.G.R.]; Fundación Caja Madrid (Beca de Movilidad para Profesores de las Universidades Públicas de Madrid 2011–2012 to L.delP); Canadian Institutes of Health Research (CIHR) [MOP-82875 to W.W.W.]; Natural Sciences and Engineering Research Council of Canada (NSERC) [RGPIN355532-10 to W.W.W.]; National Institutes of Health [1R01GM084875 toW.W.W.]; CSIC (Spanish National Research Council) [JAE-Doc grant-2010 to O.R., in part by the European Social Fund]. Spanish science, technology and innovation contract [University of Castilla-LaMancha-2014 to O.R., in part by the European Social Fund]. Funding for open access charge: MICINN [SAF2011 24225 to L.delP., SAF2014-53819-R to L.delP., B.J.

Sensitivity of boundary-layer variables to PBL schemes in the WRF model based on surface meteorological observations, lidar, and radiosondes during the HygrA-CD campaign

Air quality forecast systems need reliable and accurate representations of the planetary boundary layer (PBL) to perform well. An important question is how accurately numerical weather prediction models can reproduce conditions in diverse synoptic flow types. Here, observations from the summer 2014 HygrA-CD (Hygroscopic Aerosols to Cloud Droplets) experimental campaign are used to validate simulations from the Weather Research and Forecasting (WRF) model over the complex, urban terrain of the Greater Athens Area. Three typical atmospheric flow types were identified during the 39-day campaign based on 2-day backward trajectories: Continental, Etesians, and Saharan. It is shown that the numerical model simulations differ dramatically depending on the PBL scheme, atmospheric dynamics, and meteorological parameter (e.g., 2-m air temperature). Eight PBL schemes from WRF version 3.4 are tested with daily simulations on an inner domain at 1-km grid spacing. Near-surface observations of 2-m air temperature and relative humidity and 10-m wind speed are collected from multiple meteorological stations. Estimates of the PBL height come from measurements using a multiwavelength Raman lidar, with an adaptive extended Kalman filter technique. Vertical profiles of atmospheric variables are obtained from radiosonde launches, along with PBL heights calculated using bulk Richardson number. Daytime maximum PBL heights ranged from 2.57 km during Etesian flows, to as low as 0.37 km during Saharan flows. The largest differences between model and observations are found with simulated PBL height during Saharan synoptic flows. During the daytime, campaign-averaged near-surface variables show WRF tended to have a cool, moist bias with higher simulated wind speeds than the observations, especially near the coast. It is determined that non-local PBL schemes give the most agreeable solutions when compared with observations.Peer ReviewedPostprint (published version

Pluripotency factors regulate the onset of Hox cluster activation in the early embryo

Pluripotent cells are a transient population of the mammalian embryo dependent on transcription factors, such as OCT4 and NANOG, which maintain pluripotency while suppressing lineage specification. However, these factors are also expressed during early phases of differentiation, and their role in the transition from pluripotency to lineage specification is largely unknown. We found that pluripotency factors play a dual role in regulating key lineage specifiers, initially repressing their expression and later being required for their proper activation. We show that Oct4 is necessary for activation of HoxB genes during differentiation of embryonic stem cells and in the embryo. In addition, we show that the HoxB cluster is coordinately regulated by OCT4 binding sites located at the 3′ end of the cluster. Our results show that core pluripotency factors are not limited to maintaining the precommitted epiblast but are also necessary for the proper deployment of subsequent developmental programs.This work was funded by the Spanish government (grants BFU2017-84914-P and PID2020-115755GB-I00 to M.M.; BFU2016-74961-P and BFU2016-81887-REDT to J.L.G.-S.), the Andalusian government (grant BIO-396 to J.L.G.-S.), and the European Research Council (ERC; grant agreement 740041 to J.L.G.-S.). M.T. held Juan de la Cierva fellowships from the Spanish government (FJCI-2017-31791 and IJC2019-038897-I), R.R. and R.D.A. held FPU fellowships from the government, and J.V. was the recipient of a “La Caixa” fellowship. Work in the laboratory of J.L.G.-S. was supported by a María de Maetzu Unit of Excellence Grant (MDM-2016-0687) to the Department of Gene Regulation and Morphogenesis of the CABD. The CBMSO is supported by an institutional grant from the Fundación Ramon Areces, and the CNIC is supported by the Instituto de Salud Carlos III (ISCIII), the Ministerio de Ciencia e Innovación (MCIN), and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (grant CEX2020-001041-S funded by MICIN/AEI/10.13039/501100011033). : With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2020-001041-S)

Pluripotency factors regulate the onset of Hox cluster activation in the early embryo

Pluripotent cells are a transient population of the mammalian embryo dependent on transcription factors, such as OCT4 and NANOG, which maintain pluripotency while suppressing lineage specification. However, these factors are also expressed during early phases of differentiation, and their role in the transition from pluripotency to lineage specification is largely unknown. We found that pluripotency factors play a dual role in regulating key lineage specifiers, initially repressing their expression and later being required for their proper activation. We show that Oct4 is necessary for activation of HoxB genes during differentiation of embryonic stem cells and in the embryo. In addition, we show that the HoxB cluster is coordinately regulated by OCT4 binding sites located at the 3′ end of the cluster. Our results show that core pluripotency factors are not limited to maintaining the precommitted epiblast but are also necessary for the proper deployment of subsequent developmental programs

Influence of Resilence, Everyday Stress, Self-Efficacy, Self-Esteem, Emotional Intelligence, and Empathy on Attitudes toward Sexual and Gender Diversity Rights

The present study forms part of the project “Cross-disciplinary education for sexual, body, and gender diversity” (Code 419). The aim of this study was to analyze the role played by the psychoeducational variables involved in burnout (resilience, self-e cacy, self-esteem, emotional intelligence, empathy, and everyday stress) on attitudes toward sexual and gender diversity rights. Participants comprised 170 university students undertaking a degree in primary education. Instruments were administered to assess the constructs analyzed, ensuring informed consent, voluntary participation, anonymity, and data confidentiality. An ex post facto design was employed to determine whether attitudes toward sexual and gender diversity rights are influenced by the possible relationships and role of these variables. We found statistically significant associations between students’ attitudes toward sexual and gender diversity at all three levels (sociocultural, relational, and personal) and the variable of burnout. Attitudes towards gender sexual orientation and gender identity rights influence burnout, and vice versa. As we ponder deeply about how these factors influence one another, we can shift our perspectives in a way that builds social harmony. It is important to learn how exactly these influences work, and this knowledge translates into making teaching strategies more e ective to help raise awareness about guaranteeing rights for all. At the personal level of students’ attitudes toward sexual and gender diversity/equality, we found positive correlations between this level and the total score for the variable of resilience and with its factor of personal competence. The data obtained will be of use for future psychoeducational assessment and intervention programs related to an education in sexual orientation and gender identity rights that are aimed at developing socio-emotional competencies and attention to diversity with the ultimate goal of improving social harmony by dismantling stereotypes and raising awareness of the importance of the variables of resilience, self-e cacy, self-esteem, emotional intelligence, empathy, and everyday stress which highlights how “education is an instrument of social transformationUNESC

Methionine Sulfoxides on Prion Protein Helix-3 Switch on the α-Fold Destabilization Required for Conversion

BACKGROUND: The conversion of the cellular prion protein (PrP(C)) into the infectious form (PrP(Sc)) is the key event in prion induced neurodegenerations. This process is believed to involve a multi-step conformational transition from an alpha-helical (PrP(C)) form to a beta-sheet-rich (PrP(Sc)) state. In addition to the conformational difference, PrP(Sc) exhibits as covalent signature the sulfoxidation of M213. To investigate whether such modification may play a role in the misfolding process we have studied the impact of methionine oxidation on the dynamics and energetics of the HuPrP(125-229) alpha-fold. METHODOLOGY/PRINCIPAL FINDINGS: Using molecular dynamics simulation, essential dynamics, correlated motions and signal propagation analysis, we have found that substitution of the sulfur atom of M213 by a sulfoxide group impacts on the stability of the native state increasing the flexibility of regions preceding the site of the modification and perturbing the network of stabilizing interactions. Together, these changes favor the population of alternative states which maybe essential in the productive pathway of the pathogenic conversion. These changes are also observed when the sulfoxidation is placed at M206 and at both, M206 and M213. CONCLUSIONS/SIGNIFICANCE: Our results suggest that the sulfoxidation of Helix-3 methionines might be the switch for triggering the initial alpha-fold destabilization required for the productive pathogenic conversion

Turismo Sostenible en la Generación Millennial

La industria turística es un sector que está en constante evolución pues debe de aptarse a los cambios continuos que experimenta tanto el paisaje como la sociedad. Por eso, el presente artículo se centra en la práctica de turismo en la Generación Millennial de acuerdo con la sostenibilidad en el sector turístico. Los objetivos de este trabajo se resumen en 6: (1) Analizar el conocimiento por parte de la Generación “Y” sobre el Turismo Sostenible (2) Averiguar si la Generación Millennial toma decisiones sostenibles en el proceso de planificación de un viaje y durante el mismo (2.1) Averiguar la capacidad de gasto de esta generación (3) Analizar los factores que dificultan o impulsan a los consumidores a optar por este tipo de turismo (4) Analizar la actitud de la Generación Millennial hacia la oferta de turismo sostenible (5) Investigar si esta tendencia se ha convertido en una moda o es una creencia, y por último (6) Describir el perfil de los turistas que consumen Turismo Sostenible. Asimismo, se han analizado los antecedentes del Turismo Sostenible y la Generación Millennial para proceder posteriormente a realizar un estudio de investigación de mercados de carácter exploratorio y descriptivo sobre una muestra de jóvenes millennials en la provincia de Alicante y así dar respuesta a los objetivos del estudio y sacar sus consiguientes conclusiones