X-ray sources as tracers of the large-scale structure in the Universe

We review the current status of studies of large-scale structure in the X-ray Universe. After motivating the use X-rays for cosmological purposes, we discuss the various approaches used on different angular scales including X-ray background multipoles, cross-correlations of the X-ray background with galaxy catalogues, clustering of X-ray selected sources and small-scale fluctuations and anisotropies in the X-ray background. We discuss the implications of the above studies for the bias parameter of X-ray sources, which is likely to be moderate for X-ray selected AGN and the X-ray background (~1-2). We finally outline how all-sky X-ray maps at hard X-rays and medium surveys with large sky coverage could provide important tests for the cosmological models.Comment: Invited review presented at the Workshop X-ray Astronomy'99: Stellar endpoints, AGN and the diffuse X-ray background (Astrophys Lett and Comm

Educommunication and archaeological heritage in Italy and Spain: an analysis of institutions’ use of Twitter, sustainability, and citizen participation

Improving heritage educommunication on the web 2.0 is key to reaching certain sustainable development goals focused on educational quality and citizen participation. Although numerous partial studies have already been conducted, to date neither assessment tools nor detailed studies are available regarding the quality of educommunicative initiatives. Spain and Italy’s archaeological heritage museums have a consolidated track record on Twitter, which has been bolstered by museum closures due to COVID-19 and has resulted in a significant change to their educommunicative policies. The present article aims to analyze educommunicative actions undertaken on Twitter at Italian archaeological museums, compare their strategies with a previous study on Spanish institutions, and analyze to what degree the sustainability of heritage, citizen participation, learning opportunities, and universal access are being promoted. This mixed method analysis was carried out through the implementation of a web 2.0 heritage educommunication analysis tool focused on three key factors: educational procedure, R-elational interactions, and the prevailing learning paradigm, as well as a content analysis of the variables that comprise them. The key findings suggest that neither country is close to achieving a quality educommunicative strategy. Italian archaeological heritage institutions use Twitter simply as an advertising platform. Despite being a social media platform, participative initiatives are scarcely promoted, although heritage sustainability is promoted through raising awareness of conservation and appreciation. Spanish institutions, however, demonstrated the opposite pattern of use

Epistemic Beliefs and Pre-service Teachers’ Conceptions of History Instruction

This study investigates the difficulties pre-service history teachers face in understanding and implementing a history curriculum focused on historical reasoning. Based on the general hypothesis of beliefs exerting a direct influence on teachers’ actions, this phenomenographic study provides a qualitative analysis of the epistemic and learning/teaching conceptions on which pre-service teachers base their reflections and decisions when they have to produce a teaching plan for a specific situation, taking n = 72 pre-service teachers from the Master’s Degree in Teaching in Secondary Education at the University of Zaragoza (specialty Geography and History) as statistical sample. The outcome of the first phases of the analysis was a new theoretical reference framework that innovated by simultaneously analyzing epistemic and educational conceptions. On the one hand, the analysis results include a considerable number of pre-service teachers who use epistemic beliefs identifying history and the past when addressing the curriculum. On the other, none of them, not even those with advanced epistemic beliefs, think about the curriculum in terms of an inquiry-based approach to historical problems, and, therefore, they display a transmissive–reproductive conception of history instruction. Consequently, the main contribution is observation of a twofold threshold that pre-service teachers must cross to understand and accept an interpretive history curriculum: they must overcome the identification between past and history and instead immerse themselves in the necessarily interpretive nature of any history; and they must stop viewing learning as knowledge internalization and reproduction and, instead, embrace a conception of learning as inquiry and reasoning. Copyright © 2022 Paricio, García-Ceballos and Rubio-Navarro

On the origin of the X-ray emission from a narrow-line radioquasar at z>1

We present new XMM-Newton X-ray observations of the z=1.246 narrow-line radioquasar RX J1011.2+5545 serendipitously discovered by ROSAT. The flat X-ray spectrum previously measured by ROSAT and ASCA is shown to be the result of a steep Gamma~1.8 power law spectrum seen through a moderate intrinsic absorbing column NH~4E21 cm^-2. The position of the X-ray source is entirely coincident with the nucleus of the radio source that we have resolved in new sensitive VLA observations at 3.6 and 6 cm, implying that scattering in the radio lobes is not responsible for the bulk of X-ray emission. In the EPIC pn image, a faint patch of X-ray emission is apparent 14'' to the NE of the main X-ray source. The former is positionally coincident with an apparently extended optical object with R~21.9, but there is no associated radio emission, thus ruling out the possibility that this represents a hotspot in a jet emanating from the primary X-ray source. No reflection features are detected in the X-ray spectrum of the narrow-line radioquasar, although an Fe line with equivalent width of up to 600 eV cannot be ruled out.Comment: 7 pages, 6 figures, MNRAS in the pres

El efecto de la escala sobre los procesos de escorrentía superficial

[Resumen] En una pequeña cuenca bajo explotación de dehesa se investiga la generación de escorrentía superficial a distintas escalas. Ello incluye experimentos con lluvia simulada en microparcelas, mediciones del flujo superficial en eventos en 17 parcelas abiertas y una parcela. cerrada, y la producción de caudal de la cuenca y una subcuenca. Los coeficientes de escorrentía de las escalas consideradas se agrupan en dos conjuntos: valores bajos para la cuenca y subcuenca, y valores altos a escala de pedón y ladera. Los resultados demuestran que gran parte de la escorrentía producida en las vertientes se infiltra después en las zonas coluviales y fondos de valle. Además indican la importancia de estudiar varias escalas para entender los procesos hidrológicos que operan en cuencas.[Abstract] In a small catchment under the so-called dehesa landuse system, the production of surface runoff is investigated at different scales. This includes experiments with simulated rainfal1 at micro-plots, event-based measurements of overland flow at 17 open plots and 1 closed plot, and discharge production of the catchment and subcatchment. The runoff coefficients of the considered scales form two groups, with low values for the catchment and sub-catchment and high values for the microplots and hillslope plots. The results show that large part of runoff produced at the slopes is infiltrated afterwards at colluvial sites and the valley floors.Furthemore, they indicate the importance of studying at various scales in order to understand the hydrological processes operating in catchment

Metabolomic Characterization of Human Model of Liver Rejection Identifies Aberrancies Linked to Cyclooxygenase (COX) and Nitric Oxide Synthase (NOS)

BACKGROUND Acute liver rejection (ALR), a significant complication of liver transplantation, burdens patients, healthcare payers, and the healthcare providers due to an increase in morbidity, cost, and resources. Despite clinical resolution, ALR is associated with an increased risk of graft loss. A unique protocol of delayed immunosuppression used in our institute provided a model to characterize metabolomic profiles in human ALR. MATERIAL AND METHODS Twenty liver allograft biopsies obtained 48 hours after liver transplantation in the absence of immunosuppression were studied. Hepatic metabolites were quantitated in these biopsies by liquid chromatography and mass spectroscopy (LC/MS). Metabolite profiles were compared among: 1) biopsies with reperfusion injury but no histological evidence of rejection (n=7), 2) biopsies with histological evidence of moderate or severe rejection (n=5), and 3) biopsies with histological evidence of mild rejection (n=8). RESULTS There were 133 metabolites consistently detected by LC/MS and these were prioritized using variable importance to projection (VIP) analysis, comparing moderate or severe rejection vs. no rejection or mild rejection using partial least squares discriminant statistical analysis (PLS-DA). Twenty metabolites were identified as progressively different. Further PLS-DA using these metabolites identified 3 metabolites (linoleic acid, γ-linolenic acid, and citrulline) which are associated with either cyclooxygenase or nitric oxide synthase functionality. CONCLUSIONS Hepatic metabolic aberrancies associated with cyclooxygenase and nitric oxide synthase function occur contemporaneous with ALR. Additional studies are required to better characterize the role of these metabolic pathways to enhance utility of the metabolomics approach in diagnosis and outcomes of ALR