First observations and magnitude measurement of Starlink's Darksat

Measure the Sloan g' magnitudes of the Starlink's STARLINK-1130 (Darksat) and 1113 LEO communication satellites and determine the effectiveness of the Darksat darkening treatment at 475.4\,nm. Two observations of the Starlink's Darksat LEO communication satellite were conducted on 2020/02/08 and 2020/03/06 using a Sloan r' and g' filter respectively. While a second satellite, STARLINK-1113 was observed on 2020/03/06 using a Sloan g' filter. The initial observation on 2020/02/08 was a test observation when Darksat was still manoeuvring to its nominal orbit and orientation. Based on the successful test observation, the first main observation was conducted on 2020/03/06 along with an observation of the second Starlink satellite. The calibration, image processing and analysis of the Darksat Sloan g' image gives an estimated Sloan g' magnitude of $7.46\pm0.04$ at a range of 976.50\,km. For STARLINK-1113 an estimated Sloan g' magnitude of $6.59\pm0.05$ at a range of 941.62\,km was found. When scaled to a range of 550\,km and corrected for the solar and observer phase angles, a reduction by a factor of two is seen in the reflected solar flux between Darksat and STARLINK-1113. The data and results presented in this work, show that the special darkening coating used by Starlink for Darksat has darkened the Sloan g' magnitude by $0.77\pm0.05$\,mag, when the range is equal to a nominal orbital height (550\,km). This result will serve members of the astronomical community modelling the satellite mega-constellations, to ascertain their true impact on both the amateur and professional astronomical communities. Concurrent and further observations are planned to cover the full optical and NIR spectrum, from an ensemble of instruments, telescopes and observatories.Comment: Accepted for publication in A&A Letters. 5 pages, 2 figures and 4 table

Spectroscopic Observations of New Oort Cloud Comet 2006 VZ13 and Four Other Comets

Spectral data are presented for comets 2006 VZ13 (LINEAR), 2006 K4 (NEAT), 2006 OF2 (Broughton), 2P/Encke, and 93P/Lovas I, obtained with the Cerro-Tololo Inter-American Observatory 1.5-m telescope in August 2007. Comet 2006 VZ13 is a new Oort cloud comet and shows strong lines of CN (3880 angstroms), the Swan band sequence for C_2 (4740, 5160, and 5630 angstroms), C_3 (4056 angstroms), and other faint species. Lines are also identified in the spectra of the other comets. Flux measurements of the CN, C_2 (Delta v = +1,0), and C_3 lines are recorded for each comet and production rates and ratios are derived. When considering the comets as a group, there is a correlation of C_2 and C_3 production with CN, but there is no conclusive evidence that the production rate ratios depend on heliocentric distance. The continuum is also measured, and the dust production and dust-to-gas ratios are calculated. There is a general trend, for the group of comets, between the dust-to-gas ratio and heliocentric distance, but it does not depend on dynamical age or class. Comet 2006 VZ13 is determined to be in the carbon-depleted (or Tempel 1 type) class.Comment: 8 pages, 6 figures, 6 tables; Accepted by MNRA

739 observed NEAs and new 2-4m survey statistics within the EURONEAR network

We report follow-up observations of 477 program Near-Earth Asteroids (NEAs) using nine telescopes of the EURONEAR network having apertures between 0.3 and 4.2 m. Adding these NEAs to our previous results we now count 739 program NEAs followed-up by the EURONEAR network since 2006. The targets were selected using EURONEAR planning tools focusing on high priority objects. Analyzing the resulting orbital improvements suggests astrometric follow-up is most important days to weeks after discovery, with recovery at a new opposition also valuable. Additionally we observed 40 survey fields spanning three nights covering 11 sq. degrees near opposition, using the Wide Field Camera on the 2.5m Isaac Newton Telescope (INT), resulting in 104 discovered main belt asteroids (MBAs) and another 626 unknown one-night objects. These fields, plus program NEA fields from the INT and from the wide field MOSAIC II camera on the Blanco 4m telescope, generated around 12,000 observations of 2,000 minor planets (mostly MBAs) observed in 34 square degrees. We identify Near Earth Object (NEO) candidates among the unknown (single night) objects using three selection criteria. Testing these criteria on the (known) program NEAs shows the best selection methods are our epsilon-miu model which checks solar elongation and sky motion and the MPC's NEO rating tool. Our new data show that on average 0.5 NEO candidates per square degree should be observable in a 2m-class survey (in agreement with past results), while an average of 2.7 NEO candidates per square degree should be observable in a 4m-class survey (although our Blanco statistics were affected by clouds). At opposition just over 100 MBAs (1.6 unknown to every 1 known) per square degree are detectable to R=22 in a 2m survey based on the INT data, while our two best ecliptic Blanco fields away from opposition lead to 135 MBAs (2 unknown to every 1 known) to R=23.Comment: Published in Planetary and Space Sciences (Sep 2013

Notch/Wnt Cross-Signalling Regulates Stemness Of Dental Pulp Stem Cells Through Expression Of Neural Crest And Core Pluripotency Factors

Dental pulp stem cells (DPSCs) from adult teeth express neural crest (NC) markers together with core transcriptional factors associated with stem cell pluripotency, such as Oct4a, Sox2, c-Myc, Rex1, Stella/Dppa3, Ssea1/Fut4, Lin28 and Nanog. The possibility to boost the natural stemness features of DPSCs by mild methods, that do not involve gene and/or chromatin modification or gene transfection, is highly desirable for cell therapy. Canonical Wnt and Notch are two highly conserved developmental signalling pathways that are involved in NC emergence and stem cell self-renewal. We determined that both pathways coordinate to regulate the expression of core pluripotency and NC factors in DPSCs. Pharmacological inhibition of the Notch pathway for 48 h, by the gamma-secretase inhibitor N-[N-(3,5-Difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT), abolished the expression of NC and core factors. In addition, it induced a silencing of the canonical Wnt signalling and a clear reduction in the stemness potential of DPSCs, as shown by a reduced ability to generate mature, fully differentiated osteoblasts and adipocytes. Conversely, pharmacological activation of the Wnt pathway for 48 h, by either the glycogen synthase kinase 3 beta (GSK3-beta) inhibitor 6-bromoindirubin-3'-oxime (BIO) or the human recombinant protein Wnt-3a, not only largely increased the expression of NC and core factors, but also increased the efficiency of DPSCs to differentiate into mature osteoblasts and adipocytes. These results showed that a short preconditioning activation of Wnt/Notch signalling by small molecules and/or recombinant proteins enhanced the stemness and potency of DPSCs in culture, which could be useful for optimising the therapeutic use of these and other tissue-specific stem cells.Technical and human support provided by the analytical microscopy service of SGIKER (UPV/EHU, MINECO, GV/EJ, ERDF and ESF) is gratefully acknowledged. This work was funded by the UPV/EHU (GIU16/66, UFI 11/44) and the Basque Government (GV/EJ; IT831-13). V.U. received a fellowship from The Global Training Grant (GV/EJ) to fund a research stage at The Institute of Cancer Research (London, UK)

Climate risk disclosure, compliance, and regulatory drivers: A textual tone analysis

[eng] The way in which companies disclose and manage climate-related financial risks is a matter of increasing interest and concern for market stakeholders, particularly institutional investors. This article presents a textual analysis of the tone of climate risk disclosures by ASX200 companies from 2015 to 2019. It explores the most common tones of language used, how they differ across economic sectors, how disclosure tone is influenced by corporate governance and other company characteristics, and whether approaches are changing over time. Disclosure tone can influence the judgments and decision-making of market stakeholders. Textual analysis presents an analytical tool to help market stakeholders explore and assess a company’s perceptions and managerial judgment about climate-related risks, feeding into their broader analysis about a company’s preparedness to manage these risks and seize opportunities. It also offers insights for regulators as they develop guidance to scaffold existing legal obligations and oversee compliance in this area

The stellar occultation by Makemake on 2011 April 23

We have taken advantage of a stellar occultation by the dwarf planet Makemake on 2011 April 23, to determine several of its main physical properties. We present results from a multisite campaign with 8 positive occultation detections from 5 different sites, including data from the 8-m VLT and 3.5-m NTT telescopes in Chile, which have very high temporal resolution. Because the star was significantly fainter than Makemake (setting a record in the magnitude of a star whose occultation has been detected), the occultation resulted in a drop of just ~0.3 mag in the lightcurves. From the lightcurves we have been able to determine the size and shape of the body, its geometric albedo and constraints on its atmosphere

Socialización escolar : procesos, experiencias y trayectos

En los artículos que forman parte de este libro se despliega un conjunto de temas, problemas y debates que, en un primer momento, se hicieron presentes entre el equipo coordinador del libro y que luego fueron compartidos con los investigadores miembros del Grupo de Trabajo "Juventudes, Infancias: Políticas, Culturas e Instituciones Sociales" (GT) del Consejo Latinoamericano de Ciencias Sociales (CLACSO). En tal sentido, el propósito de la compilación consiste en aportar a la actualización de un área o campo que, desde sus inicios, fue y es pensado por las ciencias sociales: la escuela y los sistemas educativos. Sin embargo, en los últimos años, el campo de estudios sobre la escuela se ha diversificado y especializado, encontrando nuevos objetos de estudio y ampliando los ya existentes, al tiempo que los temas y problemas educativos se hablan y debaten por toda la sociedad

Rasgos de personalidad predictores del Síndrome de Quemarse por el Trabajo en profesores mexicanos

The objective of the study was to determine the predictive value of personality traits according to the Mexican model of the Five Personality Factors in the Burnout Syndrome (BOS) and its dimensions from the Gil-Monte model. Three hundred and seventy-five basic education teachers from Mexico City took part in it. The sampling was intentional, non-probabilistic with cross-sectional and correlational design. The Spanish Burnout Syndrome inventory and the Mexican Five Personality Factors scale were used. Pearson's Correlation Test and a stepwise linear regression model were employed for the analysis. With the exception of Emotional Control and Enthusiasm towards work (r2=.087; p>0.05), the results found significant correlations of the Five Mexican personality factors and BOS, negative in the case of personality traits and Psychic Burnout, Indolence, and Guilt; and positive among personality factors and enthusiasm towards work. The multiple linear regression model included Expressive Sociability, Organization and Acceptableness as BOS predictors (F= 39.8, β=-.197*). Therefore, it is concluded that these are the personality traits associated with the syndrome that have a flexible role in the development of BOS. The results also coincide with other studies. It is suggested for further research to evaluate the modulating role of these traits with Psychosocial Risk Factors as an antecedent.El objetivo fue determinar el valor predictivo de los rasgos de personalidad según el modelo de los Cinco Factores Mexicanos de la Personalidad en el Síndrome de Quemarse por el Trabajo y sus dimensiones desde el modelo del Gil-Monte. Participaron 375 profesores de educación básica de la Ciudad de México, el muestreo fue no probabilístico intencional con diseño transversal y correlacional. Se utilizó el Cuestionario para la Evaluación del Síndrome de Quemarse por el Trabajo y la Escala de los Cinco Factores Mexicanos de Personalidad. Para analizar se utilizó la Prueba de correlación de Pearson, y un modelo de regresión lineal por pasos. A excepción de Control Emocional e Ilusión en Trabajo (r2=.087; p>0.05), los resultados encontraron correlaciones significativas de los 5FM y el SQT, negativas en el caso de rasgos de personalidad y Desgaste Psíquico, Indolencia, y Culpa, positivas entre 5FM e Ilusión por el Trabajo. El modelo de regresión lineal múltiple incluyó como predictores del SQT a Sociabilidad Expresiva, Organización y Aceptabilidad (F= 39.8, β=-.197*). Se concluye que en la población de docentes estos son los rasgos de personalidad asociados al síndrome, pero tienen un papel flexible en el desarrollo del SQT. Los resultados coinciden con otros estudios. Se sugiere para investigaciones posteriores evaluar el de papel modulador de estos rasgos con Factores de Riesgo Psicosocial como antecedente

Sustainability of the accounting and finance academic profession: Students’ and supervisors’ view about the PhD supervision process

[eng] This study explores the research supervisory practices of accounting and finance PhD students at Australian and New Zealand universities. Given documented faculty shortages in the accounting and finance disciplines, such investigation is timely and relevant. In the context of student engagement with their community of academic practice and their intrinsic motivation related to individual competence and autonomy, situational adjustments are inevitable and explain some differences between students’ perceptions and supervisors’ expectations. Our findings demonstrate that, despite general satisfaction with the PhD supervision process, students articulated concerns regarding constructive feedback and pastoral care provided by their supervisors, as well as guidance regarding data analysis/statistics