208 research outputs found

    Preschool stunting, age at menarche and adolescent height: a longitudinal study in rural Senegal

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    Objective: To study the impact of preschool stunting on adolescent height and age at menarche in rural West Africa. Design: A longitudinal, population-based study. Setting: The Niakhar study area in Central Senegal. Subjects: 1650 children aged 12-17y with known height-for-age at the age of 2-5y. Main outcome measures: Adolescent height; mean age at menarche of girls estimated by the status quo method. Results: The subjects were divided into three groups of preschool height-for-age: < -2, -2 to -1 and > -1 z-score of the NCHS reference. The mean height during adolescence differed significantly according to preschool height-for-age for both boys and girls (P < 0.001). Relative risk of adolescent stunting according to preschool stunting varied from 2.0-4.0 depending on age and sex. Estimated mean age at menarche was 17.2 (95% fiducial confidence interval: 16.6-18.7), 16.5 (16.1-17.2) and 15.6 (15.2-16.0) y, respectively, for the three groups of preschool height-for-age (P < 0.001). Mean increment from age 5 y to adolescence did not differ significantly among the boys according to preschool stunting, but among the girls aged 16-17 y, the increment was higher for those who had been stunted during preschool life ( P < 0.01). Conclusion: Some evidence of catch-up growth between the ages of 5 and 17 y was found for stunted girls. The significant delay in sexual maturation of the stunted girls suggests that stunted children of both sexes have a possibility of catch-up growth after the age of 17 y. Sponsorship: The preschool study was supported by the EEC (TSD-036)

    Impact of materials technology on the breeding blanket design – Recent progress and case studies in materials technology

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    A major part in the EUROfusion materials research program is dedicated to characterize and quantify nuclear fusion specific neutron damage in structural materials. While the majority of irradiation data gives a relatively clear view on the displacement damage, the effect of transmutation – i.e. especially hydrogen and helium production in steels – is not yet explored very well. However, few available results indicate that EUROFER-type steels will reach their operating limit as soon as the formation of helium bubbles reaches a critical amount or size. At that point, the material would fail due to embrittlement at the considered load. This paper presents a strategy for the mitigation of the before-mentioned problem using the following facts: • the neutron dose and related transmutation rate decreases quickly inside the first wall, that is, only a plasma-near area is extremely loaded • nanostructured oxide dispersion strengthened (ODS) steels may have an enormous trapping effect on helium and hydrogen, which would suppress the formation of large helium bubbles • compared to conventional steels, ODS steels show improved irradiation tensile ductility and creep strength In summary, producing the plasma facing, highly neutron and heat loaded part of blankets by an ODS steel, while using EUROFER97 for everything else, would allow a higher heat flux as well as a longer operating period. Consequently, we (1) developed and produced 14 % Cr ferritic ODS steel plates. (2) We fabricated a mockup with 5 cooling channels and a plated first wall of ODS steel, using the same production processes as for a real component. And finally, (3) we performed high heat flux tests in the HELOKA facility (Helium Loop Karlsruhe at KIT) applying short and up to 2 h long pulses, in which the operating temperature limit for EUROFER97 (i.e., 550 °C) was finally exceeded by 100 K. Thereafter, microstructure and defect analyses did not reveal defects or recognizable damage. Only a heat affected zone in the EUROFER/ODS steel interface could be detected. This demonstrates that the use of ODS steel could make a decisive difference in the future design and performance of breeding blankets

    Fabrication routes for advanced first wall design alternatives

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    In future nuclear fusion reactors, plasma facing components have to sustain specific neutron damage. While the majority of irradiation data provides a relatively clear picture of the displacement damage, the effect of helium transmutation is not yet explored in detail. Nevertheless, available results from simulation experiments indicate that 9%-chromium steels will reach their operating limit as soon as the growing helium bubbles extent a critical size. At that point, the material would most probably fail due to grain boundary embrittlement. In this contribution, we present a strategy for the mitigation of the before-mentioned problem using the following facts. (1) The neutron dose and related transmutation rate decreases quickly inside the first wall of the breeding blankets, that is, only a plasma-near area is extremely loaded. (2) Nanostructured oxide dispersion strengthened (ODS) steels may have an enormous trapping effect on helium, which would suppress the formation of large helium bubbles for a much longer period. (3) Compared to conventional steels, ODS steels also provide improved irradiation tensile ductility and creep strength. Therefore, a design, based on the fabrication of the plasma facing and highly neutron and heat loaded parts of blankets by an ODS steel, while using EUROFER97 for everything else, would extend the operating time and enable a higher heat flux. Consequently, we (i) developed and produced 14%Cr ferritic ODS steel plates and (ii) optimized and demonstrated a scalable industrial production route. (iii) We fabricated a mock-up with five cooling channels and a plated first wall of ODS steel, using the same production processes as for a real component. (iv) Finally, we performed high heat flux tests in the Helium Loop Karlsruhe, applying a few hundred short and a few 2 h long pulses, in which the operating temperature limit for EUROFER97 (i.e. 550 ◦C) was finally exceeded by 100 K. (v) Thereafter, microstructure and defect analyses did not reveal critical defects or recognizable damage. Only a heat affected zone in the EUROFER/ODS steel interface could be detected. However, a solution to prohibit the formation of such heat affected zones is given. These research contributions demonstrate that the use of ODS steel is not only feasible and affordable but could make a decisive difference in the future design and performance of breeding blankets

    ‘Mind the gap’: Responding to the indeterminable in migration

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    Prompted by the paper by Miriam Tedeschi, this commentary attempts to unsettle the dominant understanding of a relation in migration research that prioritises linkages between people, places and organisations while treating boundaries as limits to overcome. Building on geographers’ earlier engagements with Adorno, Levinas and extending this conversation to include Blanchot, the analysis attempts to move beyond the hold of mastery on a relation with alterity. The paper argues for an interruptive non-relation that resists the appropriation and affirms the dispersion of the self by the alterity it cannot internalise. It offers an alternative response to difference in migration that avoids bringing it to unifying continuity. Instead of treating interruptions in migration as gaps to be resolved through language, the paper considers the possibility of a neutral writing that reflects the powerlessness to say the unspeakable. In a movement of inscription and effacement, neutral writing invokes the unspeakable pain and affliction that exceeds the concepts to which it gives rise. The neuter answers for the non-subject of loss and trauma, the nothing often haunting international migrants

    Philosophy as political technē: The tradition of invention in Simondon’s political thought

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    Gilbert Simondon has recently attracted the interest of political philosophers and theorists, despite he is rather renowned as a philosopher of technics – as the author of Of the Mode of Existence of Technical Objects – who also elaborated a general theory of complex systems in Individuation in the Light of the Notions of Form and Information. A group of scholars has developed Gilles Deleuze’s early suggestion that Simondon’s social ontology might offer the basis for a re-theorisation of radical democracy. Others, following Herbert Marcuse, have instead focused on Simondon’s analysis of the relationship between technology and society. However, only a joint study of Simondon’s two major works can reveal their implicit political stakes. As I will argue, Simondon’s anti-Aristotelianism and his anti-Heideggerian understanding of the Greek origins of philosophy, allow us to conceive philosophical thought as a ‘tradition of invention’, that is, a pedagogical technē endowed with the political task of maintaining the openness of the social system and allowing normative invention to emerge from within

    A Trial of the Efficacy, Safety and Impact on Drug Resistance of Four Drug Regimens for Seasonal Intermittent Preventive Treatment for Malaria in Senegalese Children

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    UNLABELLED: In the Sahel, most malaria deaths occur among children 1-4 years old during a short transmission season. A trial of seasonal intermittent preventive treatment (IPT) with sulfadoxine-pyrimethamine (SP) and a single dose of artesunate (AS) showed an 86% reduction in the incidence of malaria in Senegal but this may not be the optimum regimen. We compared this regimen with three alternatives. METHODS: 2102 children aged 6-59 months received either one dose of SP plus one dose of AS (SP+1AS) (the previous regimen), one dose of SP plus 3 daily doses of AS (SP+3AS), one dose of SP plus three daily doses of amodiaquine (AQ) (SP+3AQ) or 3 daily doses of AQ and AS (3AQ+3AS). Treatments were given once a month on three occasions during the malaria transmission season. The primary end point was incidence of clinical malaria. Secondary end-points were incidence of adverse events, mean haemoglobin concentration and prevalence of parasites carrying markers of resistance to SP. FINDINGS: The incidence of malaria, and the prevalence of parasitaemia at the end of the transmission season, were lowest in the group that received SP+3AQ: 10% of children in the group that received SP+1AS had malaria, compared to 9% in the SP+3AS group (hazard ratio HR 0.90, 95%CI 0.60, 1.36); 11% in the 3AQ+3AS group, HR 1.1 (0.76-1.7); and 5% in the SP+3AQ group, HR 0.50 (0.30-0.81). Mutations associated with resistance to SP were present in almost all parasites detected at the end of the transmission season, but the prevalence of Plasmodium falciparum was very low in the SP+3AQ group. CONCLUSIONS: Monthly treatment with SP+3AQ is a highly effective regimen for seasonal IPT. Choice of this regimen would minimise the spread of drug resistance and allow artemisinins to be reserved for the treatment of acute clinical malaria

    The techno-ecological practice as the politics of ontological coalitions

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    The paper focuses on the art projects aimed at visualizing (grasping) the physical or biological phenomena through interfaces and / or installations designed specifically for such purpose. Such works often mirror the post-­digital condition of our time where the digital technologies constitute the common background for everyday activities, no longer having the allure of "new" and "exciting" (Berry, Dieter et al., 2015). In this process, both the networked technologies of wireless communication and the act of crossing the boundaries between the digital and the physical play the crucial role as the post-­digital networked imagery increasingly becomes directly connected to the physical environment. I would like to ponder on the questions of processuality and relationality involved in such instances where the complexity of the hybrid works of art clearly transgresses the paradigm of representationalism (Thrift, 2008;; Anderson and Harrison, 2010;; Kember and Zylinska, 2012). The particular attention is given to the fact that such artworks bond different ontological realms (discursive, physical, digital) and different agents (human and non-­human, carbon-­based and software-­based) forging “ontological coalitions” (Malafouris, 2013). Throughout the article the mutlirealist and relational perspective is offered, inspired by the propositions of Gilbert Simondon and Etienne Souriau. Based on the research project supported by National Science Centre Poland ("The aesthetics of post-­digital imagery: between new materialism and object-­oriented philosophy", 2016/21/B/HS2/00746)

    New Technologies’ Promise to the Self and the Becoming of the Sacred: Insights from Georges Bataille’s Concept of Transgression

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    This article draws on Georges Bataille’s concept of transgression, a key element in Bataille’s theory of the sacred, to highlight structural implications of the way the self-empowerment ethos of new technologies suffuses the digital tracking culture. Pointing to the original conceptual stance of transgression, worked out against prohibition, I first argue that, beyond a critique of new technologies’ promise of self-empowerment as coming at the expense of an acknowledgement of the ultimate taboo—death—is the problem of the sanitizing of the tension between the crossing of the line of the symbolic taboo and prohibition; this undermines a “libidinal investment” towards the sacred, which is central in Bataille’s theory. Second, focussing on “eroticism”, since this embodies the emancipative potential of the Bataillean sacred, I argue that while a fear of eroticism marks out the digital technological realm, this is covered up by the blurring of boundaries between pleasure, fun and sex(iness) that currently governs our experience with technological devices
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