The ionospheric response over the UK to major bombing raids during World War II

The Earth’s ionosphere is subject to disturbance from above (via solar variability and space weather effects) and from below (such as tectonic activity, thunderstorms and sudden stratospheric warmings). Identifying the relative contribution of these effects remains challenging, despite recent advances in spacecraft monitoring near-Earth space. Man-made explosions provide a quantifiable proxy for natural terrestrial sources, enabling their impact on ionospheric variability to be studied. In this paper, the contribution of ground-based disturbances to ionospheric variability is investigated by considering the response of the ionospheric F2-layer over Slough, UK, to 152 major bombing raids over Europe during World War II, using a superposed epoch analysis. The median response of the F2 layer is a significant decrease in peak electron concentration (~0.3 MHz decrease in foF2). This response is consistent with wave energy heating the thermosphere, enhancing the (temperature dependant) loss rate of O+ ions. The analysis was repeated for a range of thresholds in both time of bombing before the (noon) ionospheric measurement and tonnage of bombs dropped per raid. It was found that significant (~2-3σ) deviations from the mean occurred for events occurring between approximately 3 and 7 hours ahead of the noon ionospheric measurements and for raids using a minimum of between 100 and 800 tonnes of high explosives. The most significant ionospheric response (2.99σ) occurred for 21 raids up to 5 hours before the ionospheric measurement, each with a minimum of 300 tonnes of explosives. To ensure that the observed ionospheric response cannot be attributable to space weather sources, the analysis was restricted to those events for which the geomagnetic Ap index was less than 48 (Kp < 5). Digitisation of the early ionospheric data would enable the investigation into the response of additional ionospheric parameters (sporadic E, E and F1 layer heights and peak concentrations). One metric ton of TNT has an explosive energy of 4.184 109 joules, which is of the same order of energy as a cloud to ground lightning stroke. Since the occurrence of lightning has distinctive diurnal and seasonal cycles, it is feasible that a similar mechanism could contribute to the observed seasonal anomaly in ionospheric F-region electron concentrations. Further investigation, using less extreme examples, is required to determine the minimum explosive energy required to generate a detectable ionospheric response

Interoperable geographically distributed astronomical infrastructures: technical solutions

The increase of astronomical data produced by a new generation of observational tools poses the need to distribute data and to bring computation close to the data. Trying to answer this need, we set up a federated data and computing infrastructure involving an international cloud facility, EGI federated, and a set of services implementing IVOA standards and recommendations for authentication, data sharing and resource access. In this paper we describe technical problems faced, specifically we show the designing, technological and architectural solutions adopted. We depict our technological overall solution to bring data close to computation resources. Besides the adopted solutions, we propose some points for an open discussion on authentication and authorization mechanisms.Comment: 4 pages, 1 figure, submitted to Astronomical Society of the Pacific (ASP

Shooting Rommel: the Desert Fox (1951) and Hollywood’s public-private diplomacy

The Desert Fox (Henry Hathaway, Twentieth Century-Fox; US, 1951) was one of the first war films to be produced by Hollywood after World War II. The article traces the screenwriting process through the papers of Nunnally Johnson, held at Boston University, and his correspondence with the author of the biography on which the film was based, Desmond Young, but also the studio's head of production, Darryl F. Zanuck, held at USC. The main focus of the piece is the film's reception in the Federal Republic of Germany, and the political concerns of the US State Department which tried to block its release there. This was the most politically controversial film for US diplomats at a time of great sensitivity during West German rearmament, and has left more of a paper trail than any other war film dealing with the Germans of the 1950s. The paper suggests that the film touched raw nerves both among leftwing pacifists and rightwing army sympathisers, as well as generating negative echoes behind the Iron Curtain. The author has also compared the English-language print of Desert Fox with the German-language print of Rommel der Wüstenfuchs to show that important changes were made to the script as a form of post-censorship

Listening behind the Curtain: BBC broadcasting to East Germany and its Cold War echo

This article considers the BBC External Service's East German wing, which broadcast from 1949 on, focusing on the continuities in broadcast techniques between wartime anti-Nazi programming and slots such as 'Two Comrades' and 'The Bewildered Newspaper Reader', both of which replicated pre-1945 formats. The role of the Foreign Office, both as cold warrior in the 1940s and force for detente in the 1970s is included. The article also investigates the response from German listeners to the BBC's external service broadcasting in the 1950s and 1960s. The BBC paid special attention to its German listeners, and has preserved a large number of original letters at the Written Archive at Caversham, as well as conducting regular listener surveys. These considered whether Britain's democratic agenda was getting across in the late 1940s and 50s, but the author also considers to what extent German listeners were pressing for a harder stance in the Cold War or were urging caution on the great powers deciding their fate

Introductory programming: a systematic literature review

As computing becomes a mainstream discipline embedded in the school curriculum and acts as an enabler for an increasing range of academic disciplines in higher education, the literature on introductory programming is growing. Although there have been several reviews that focus on specific aspects of introductory programming, there has been no broad overview of the literature exploring recent trends across the breadth of introductory programming. This paper is the report of an ITiCSE working group that conducted a systematic review in order to gain an overview of the introductory programming literature. Partitioning the literature into papers addressing the student, teaching, the curriculum, and assessment, we explore trends, highlight advances in knowledge over the past 15 years, and indicate possible directions for future research

Sustainable production and pharmaceutical applications of β-glucan from microbial sources

β-glucans are a large class of complex polysaccharides found in abundant sources. Our dietary sources of β-glucans are cereals that include oats and barley, and non-cereal sources can consist of mushrooms, microalgae, bacteria, and seaweeds. There is substantial clinical interest in β-glucans; as they can be used for a variety of diseases including cancer and cardiovascular conditions. Suitable sources of β-glucans for biopharmaceutical applications include bacteria, microalgae, mycelium, and yeast. Environmental factors including culture medium can influence the biomass and ultimately β-glucan content. Therefore, cultivation conditions for the above organisms can be controlled for sustainable enhanced production of β-glucans. This review discusses the various sources of β-glucans and their cultivation conditions that may be optimised to exploit sustainable production. Finally, this article discusses the immune-modulatory potential of β-glucans from these sources.ye

Post-depositional fracturing and subsidence of pumice flow deposits: Lascar Volcano, Chile

Unconsolidated pyroclastic flow deposits of the 1993 eruption of Lascar Volcano, Chile, have, with time, become increasingly dissected by a network of deeply penetrating fractures. The fracture network comprises orthogonal sets of decimeter-wide linear voids that form a pseudo-polygonal grid visible on the deposit surface. In this work, we combine shallow surface geophysical imaging tools with remote sensing observations and direct field measurements of the deposit to investigate these fractures and their underlying causal mechanisms. Based on ground penetrating radar images, the fractures are observed to have propagated to depths of up to 10 m. In addition, orbiting radar interferometry shows that deposit subsidence of up to 1 cm/year occurred between 1993 and 1996 with continued subsidence occurring at a slower rate thereafter. In situ measurements show that 1 m below the surface, the 1993 deposits remain 5°C to 15°C hotter, 18 years after emplacement, than adjacent deposits. Based on the observed subsidence as well as estimated cooling rates, the fractures are inferred to be the combined result of deaeration, thermal contraction, and sedimentary compaction in the months to years following deposition. Significant environmental factors, including regional earthquakes in 1995 and 2007, accelerated settling at punctuated moments in time. The spatially variable fracture pattern relates to surface slope and lithofacies variations as well as substrate lithology. Similar fractures have been reported in other ignimbrites but are generally exposed only in cross section and are often attributed to formation by external forces. Here we suggest that such interpretations should be invoked with caution, and deformation including post-emplacement subsidence and fracturing of loosely packed ash-rich deposits in the months to years postemplacement is a process inherent in the settling of pyroclastic material

Reflexive and Selective Competitive Behaviors—Inertia, Imitation, and Interfirm Rivalry

Competitive dynamics research has established the important impact that the level of firm competitive activity has on rival response and firm performance. Less understood, however, are inputs that influence firm activity, specifically, the extent to which firms reflexively repeat prior activity versus selectively taking actions. Drawing from the awareness–motivation–capability framework, we develop and test theory that firm decision makers are not only predisposed to behave reflexively, but are also influenced by contextual factors, suggesting cognitive selection. Utilizing a longitudinal sample of marketing activity of 58 firms and 2,164 firm–rival dyads in 11 industries, we find that firms undertake both reflexive and selective competitive processes. Positive effects of prior levels of activity are moderated by the firm’s own prior performance, as well as the rivals’ similarity and industry standing