Scale invariant jets: from blazars to microquasars

Black holes, anywhere in the stellar-mass to supermassive range, are often associated with relativistic jets. Models suggest that jet production may be a universal process common in all black hole systems regardless of their mass. Although in many cases observations support such hypotheses for microquasars and Seyfert galaxies, little is known on whether boosted blazar jets also comply with such universal scaling laws. We use uniquely rich multiwavelength radio light curves from the F-GAMMA program and the most accurate Doppler factors available to date to probe blazar jets in their emission rest frame with unprecedented accuracy. We identify for the first time a strong correlation between the blazar intrinsic broad-band radio luminosity and black hole mass, which extends over $\sim$ 9 orders of magnitude down to microquasars scales. Our results reveal the presence of a universal scaling law that bridges the observing and emission rest frames in beamed sources and allows us to effectively constrain jet models. They consequently provide an independent method for estimating the Doppler factor, and for predicting expected radio luminosities of boosted jets operating in systems of intermediate or tens-of-solar mass black holes, immediately applicable to cases as those recently observed by LIGO.Comment: 13 pages, 4 figures, accepted for publication in AP

Pedagogical leadership: A comparative study from England, Greece and Sweden

Current international research addresses the complexities, challenges and barriers that impact formal accountable leadership in the field of Early Childhood Education and Care (ECEC) as well as its conceptualisations (e.g. Nicholson and Maniates 2016, Caroll-Lind et al 2016, Nicholson et al 2020). For example, a literature review of English ECEC found that there is a distinction between organisational leadership and pedagogical leadership (Pascal et al 2020). Pedagogical leaders are the ones who might not have any organisational responsibilities but lead the direct interactions between children and adults and the educational elements that constitute the pedagogy. They also highlight that in England there is no clear route to a leadership qualification for staff in ECEC

Deep optical study of the mixed-morphology supernova remnant G 132.7+1.3 (HB3)

We present optical CCD images of the large supernova remnant (SNR) G 132.7+1.3 (HB3) covering its full extent for the first time, in the emission lines of Hα +[N II], [S II], and [O III], where new and known filamentary and diffuse structures are detected. These observations are supplemented by new low-resolution long-slit spectra and higher resolution images in the same emission lines. Both the flux-calibrated images and spectra confirm that the optical emission originates from shock-heated gas since the [S II]/Hα > 0.4. Our findings are also consistent with the recently developed emission-line ratio diagnostics for distinguishing SNRs from H II regions. A multiwavelength comparison among our optical data and relevant observations in radio, X-rays, gamma-rays and CO bands, provided additional evidence on the interaction of HB3 with the surrounding clouds and clarified the borders of the SNR and the adjacent cloud. We discuss the supernova (SN) properties and evolution that led to the current observables of HB3 and we show that the remnant has most likely passed at the pressure driven snowplow phase. The estimated SN energy was found to be (3.7 ± 1.5) × 1051 erg and the current SNR age (5.1 ± 2.1) × 104 yr. We present an alternative scenario according to which the SNR evolved in the wind bubble cavity excavated by the progenitor star and currently is interacting with its density walls. We show that the overall mixed morphology properties of HB3 can be explained if the SN resulted by a Wolf−Rayet progenitor star with mass ∼34 M⊙⁠

Digital Literacy and young children: towards better understandings of the benefits and challenges of digital technologies in homes and early years settings. : Policy briefing of DigiLitEY COST Action IS1410 and the Digital Childhoods SIG of the European Early Childhood Research Association.

Non peer reviewe

An ecological exploration of the Internet of Toys in early childhood everyday life

Throughout this chapter, the focus is on the importance of children’s agency in their use of Internet of Toys (IoToys). We think about children’s capabilities as part of digitally mediated eco-communities. Informed by the socio-ecological model, children’s, practitioners’ and parents’ dispositions helped contextualise the factors that shape children’s use of IoToys. We provide the following key messages throughout the chapter: 1.A discussion of passivity or empowerment as part of children’s digital lives with IoToys, in line with Craft’s (2013) work. 2.A reanalysis of perceptions of childhood in the digital age, linking to the sociological models of childhood and the role of children as competent and agentic. 3.An account of socio-ecological influences on digital lives, likened to Rogoff’s (2008) three planes relating to individual, interpersonal and community alongside a discussion of how the interpersonal plane can be reimagined to include interactions between child and machine. 4.A note of caution against the passive child agenda and recurrent moral panic

Digital Literacy and young children: towards better understandings of the benefits and challenges of digital technologies in homes and early years settings

This policy brief is based on an extensive body of research across Europe and elsewhere conducted by leading researchers in the field across more than 30 countries. We have studied the use of digital technologies by children under 8 years old in a variety of settings using an extensive range of research methods