Hadronic versus leptonic origin of gamma-ray emission from supernova remnants

GeV and TeV emission from the forward shocks of supernova remnants (SNRs) indicates that they are capable particle accelerators, making them promising sources of Galactic cosmic rays (CRs). However, it remains uncertain whether this $\gamma$-ray emission arises primarily from the decay of neutral pions produced by very high energy hadrons, or from inverse-Compton and/or bremsstrahlung emission from relativistic leptons. By applying a semi-analytic approach to non-linear diffusive shock acceleration (NLDSA) and calculating the particle and photon spectra produced in different astrophysical environments, we parametrize the relative strength of hadronic and leptonic emission. We show that, even if CR acceleration is likely to occur in all SNRs, the observed photon spectra may instead primarily reflect the environment surrounding the SNR, specifically the ambient density and radiation field. We find that the most hadronic-appearing spectra are young and found in environments of high density but low radiation energy density. This study aims to guide the interpretation of current $\gamma$-ray observations and single out the best targets of future campaigns.Comment: 9 pages, 6 figures, submitted to Ap

Radio Continuum Emission from the Magnetar SGR J1745-2900: Interaction with Gas Orbiting Sgr A*

We present radio continuum light curves of the magnetar SGR J1745$-$2900 and Sgr A* obtained with multi-frequency, multi-epoch Very Large Array observations between 2012 and 2014. During this period, a powerful X-ray outburst from SGR J1745$-$2900 occurred on 2013-04-24. Enhanced radio emission is delayed with respect to the X-ray peak by about seven months. In addition, the flux density of the emission from the magnetar fluctuates by a factor of 2 to 4 at frequencies between 21 and 41 GHz and its spectral index varies erratically. Here we argue that the excess fluctuating emission from the magnetar arises from the interaction of a shock generated from the X-ray outburst with the orbiting ionized gas at the Galactic center. In this picture, variable synchrotron emission is produced by ram pressure variations due to inhomogeneities in the dense ionized medium of the Sgr A West bar. The pulsar with its high transverse velocity is moving through a highly blue-shifted ionized medium. This implies that the magnetar is at a projected distance of $\sim0.1$ pc from Sgr A* and that the orbiting ionized gas is partially or largely responsible for a large rotation measure detected toward the magnetar. Despite the variability of Sgr A* expected to be induced by the passage of the G2 cloud, monitoring data shows a constant flux density and spectral index during this periodComment: 12 pages, 3 figures, ApJL (in press

Seabed characterization: developing fit for purpose methodologies

We briefly describe three methods of seabed characterization which are ‘fit for purpose’, in that each approach is well suited to distinct objectives e.g. characterizing glacial geomorphology and shallow glacial geology vs. rapid prediction of seabed sediment distribution via geostatistics. The methods vary from manual ‘expert’ interpretation to increasingly automated and mathematically based models, each with their own attributes and limitations. We would note however that increasing automation and mathematical sophistication does not necessarily equate to improve map outputs, or reduce the time required to produce them. Judgements must be made to select methodologies which are most appropriate to the variables mapped, and according to the extent and presentation scale of final maps

“Feeling Warmth and Close to Her”: Communication and Resilience Reflected in Turning Points in Positive Adult Stepchild–Stepparent Relationships

With the goal of understanding the development of positive stepchild–stepparent relationships, the researchers focused on turning points characterizing the interaction of adult stepchildren who have a positive bond with a stepparent. Engaging a relational turning points perspective, 38 stepchildren (males and females, ages 25 to 52 years old) who reported a positive stepparent relationship were interviewed, generating 269 turning points which were categorized into 15 turning point types and coded by valence. Turning points occurring most frequently were: prosocial actions, quality time, conflict/ disagreement, changes in household/family composition, and rituals. Findings are discussed, including implications for developing and enacting resilient and positive stepchild–stepparent relationships and future directions for researchers wanting to focus on positive family interaction

“Feeling Warmth and Close to Her”: Communication and Resilience Reflected in Turning Points in Positive Adult Stepchild–Stepparent Relationships

With the goal of understanding the development of positive stepchild–stepparent relationships, the researchers focused on turning points characterizing the interaction of adult stepchildren who have a positive bond with a stepparent. Engaging a relational turning points perspective, 38 stepchildren (males and females, ages 25 to 52 years old) who reported a positive stepparent relationship were interviewed, generating 269 turning points which were categorized into 15 turning point types and coded by valence. Turning points occurring most frequently were: prosocial actions, quality time, conflict/ disagreement, changes in household/family composition, and rituals. Findings are discussed, including implications for developing and enacting resilient and positive stepchild–stepparent relationships and future directions for researchers wanting to focus on positive family interaction

Quantifying and valuing carbon flows and stores in coastal and shelf ecosystems in the UK

Evidence shows that habitats with potential to mitigate against greenhouse gases emissions, by taking up and storing CO2, are being lost due to the effects of on-going human activities and climate change. The carbon storage by terrestrial habitats (e.g. tropical forests) and the role of coastal habitats (‘Blue Carbon’) as carbon storage sinks is well recognised. Offshore shelf sediments are also a manageable carbon store, covering ∼9% of global marine area, but not currently protected by international agreements to enable their conservation. Through a scenario analysis, we explore the economic value of the damage of human activities and climate change can inflict on UK marine habitats, including shelf sea sediments. In a scenario of increased human and climate pressures over a 25-year period, we estimate damage costs up to US$12.5 billion from carbon release linked to disturbance of coastal and shelf sea sediment carbon stores. It may be possible to manage socio-economic pressure to maintain sedimentary carbon storage, but the trade-offs with other global social welfare benefits such as food security will have to be taken into account. To develop effective incentive mechanisms to preserve these valuable coastal and marine ecosystems within a sustainability governance framework, robust evidence is required

Scientific advice and public policy: expert advisers’ and policymakers’ discourses on boundary work

This article reports on considerable variety and diversity among discourses on their own jobs of boundary workers of several major Dutch institutes for science-based policy advice. Except for enlightenment, all types of boundary arrangements/work in the Wittrock-typology (Social knowledge and public policy: eight models of interaction. In: Wagner P (ed) Social sciences and modern states: national experiences and theoretical crossroads. Cambridge University Press, Cambridge, 1991) do occur. ‘Divergers’ experience a gap between science and politics/policymaking; and it is their self-evident task to act as a bridge. They spread over four discourses: ‘rational facilitators’, ‘knowledge brokers’, ‘megapolicy strategists’, and ‘policy analysts’. Others aspire to ‘convergence’; they believe science and politics ought to be natural allies in preparing collective decisions. But ‘policy advisors’ excepted, ‘postnormalists’ and ‘deliberative proceduralists’ find this very hard to achieve

Democratic cultural policy : democratic forms and policy consequences

The forms that are adopted to give practical meaning to democracy are assessed to identify what their implications are for the production of public policies in general and cultural policies in particular. A comparison of direct, representative, democratic elitist and deliberative versions of democracy identifies clear differences between them in terms of policy form and democratic practice. Further elaboration of these differences and their consequences are identified as areas for further research

Convincing the crowd: entrepreneurial storytelling in crowdfunding campaigns

This study examines the structure of entrepreneurial stories in pursuit of mobilizing resources from crowds. Based on a comparative analysis of Kickstarter crowdfunding campaigns, we examine in particular how, across different project types, project histories and potential futures are framed and interlinked in narratives to appeal to funders. We find that projects are narrated in different styles—as ongoing journeys” or “results-inprogress”— to convey project value. The former style narrates projects as longer-term endeavors powered by creative initial ideas and a bold vision, inviting audiences to “join the journey”; the latter narrates projects more narrowly as a progression of accomplishments, engaging the audience instrumentally to support next steps. We find that styles are used and combined in different ways, reflecting the tangibility of project outcomes, the sophistication of technology, and the social orientation of projects. Also, successful differ from unsuccessful campaigns in using narratives more coherently. Findings inform research on narrative processes in entrepreneurship and innovation, and research on the mobilization of crowds