12 research outputs found

    Developmental differences in the control of action selection by social information

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    Our everyday actions are often performed in the context of a social interaction. We previously showed that, in adults, selecting an action on the basis of either social or symbolic cues was associated with activations in the fronto-parietal cognitive control network, whereas the presence and use of social versus symbolic cues was in addition associated with activations in the temporal and medial prefrontal cortex (MPFC) social brain network. Here we investigated developmental changes in these two networks. Fourteen adults (21–30 years of age) and 14 adolescents (11–16 years) followed instructions to move objects in a set of shelves. Interpretation of the instructions was conditional on the point of view of a visible “director” or the meaning of a symbolic cue (Director Present vs. Director Absent) and the number of potential referent objects in the shelves (3-object vs. 1-object). 3-object trials elicited increased fronto-parietal and temporal activations, with greater left lateral prefrontal cortex and parietal activations in adults than adolescents. Social versus symbolic information led to activations in superior dorsal MPFC, precuneus, and along the superior/middle temporal sulci. Both dorsal MPFC and left temporal clusters exhibited a Director × Object interaction, with greater activation when participants needed to consider the directors' viewpoints. This effect differed with age in dorsal MPFC. Adolescents showed greater activation whenever social information was present, whereas adults showed greater activation only when the directors' viewpoints were relevant to task performance. This study thus shows developmental differences in domain-general and domain-specific PFC activations associated with action selection in a social interaction context

    Dynamic causal modelling of effective connectivity during perspective taking in a communicative task

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    Previous studies have shown that taking into account another person's perspective to guide decisions is more difficult when their perspective is incongruent from one's own compared to when it is congruent. Here we used dynamic causal modelling (DCM) for functional magnetic resonance imaging (fMRI) to investigate effective connectivity between prefrontal and posterior brain regions in a task that requires participants to take into account another person's perspective in order to guide the selection of an action. Using a new procedure to score model evidence without computationally costly estimation, we conducted an exhaustive search for the best of all possible models. The results elucidate how the activity in the areas from our previously reported analysis (Dumontheil et al., 2010) are causally linked and how the connections are modulated by both the social as well as executive task demands of the task. We find that the social demands modulate the backward connections from the medial prefrontal cortex (MPFC) more strongly than the forward connections from the superior occipital gyrus (SOG) and the medial temporal gyrus (MTG) to the MPFC. This was also the case for the backward connection from the MTG to the SOG. Conversely, the executive task demands modulated the forward connections of the SOG and the MTG to the MPFC more strongly than the backward connections. We interpret the results in terms of hierarchical predictive coding

    Commentary: Three ways to falsify the case for mass deworming against soil-transmitted helminths.

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    Preprint commentary on "The Impact of Mass Deworming Programmes on Schooling and Economic Development: An Appraisal of Long-Term Studies" published in the International Journal of Epidemiology. <div><br></div><div>Citation: </div><div>Hillebrandt, H., (2016) Commentary: Three ways to falsify the case for mass deworming against soil-transmitted helminths. International Journal of Epidemiology. DOI: 10.1093/ije/dyw347</div

    SPM analysis of Human Connectome Project Task data

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    <p>Analysis of the data from the human connectome with SPM</p

    How to have Google scholar index your self published reply to any paper

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    <p>This is a BETA version of what is eventually supposed to be a template to quickly self-publish a reply to any paper. The template is formatted so that it should be indexed by google scholar.</p

    Update on the effectiveness of the bednet distributions by the Against Malaria Foundation (AMF) (Working Paper)

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    <p>This this a literature review on the effectiveness of Long lasting insecticide treated net distributions with a focus on the operations by the Against Malaria Foundation (AMF)</p

    Cause report: Cancer

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    Cause-level evaluation of the most cost-effective charitable interventions for reducing cancer prevalenc

    GoSolAr DLRs Gossamer Solar Array Conceptual Demonstrator

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    The power demand for future satellite applications will continue to rise. Geostationary telecom-munication satellites currently approach a power level of up to 20 kW. Future spacecraft will provide more transponders and/or direct mobile-satellite services. Electric propulsion is increas-ingly used for station keeping, attitude control and GEO circularization. Interplanetary missions already use kW-range electric propulsion. Space Tugs are studied for several fields. Suitable en-gines require 100 kW or more. The envisaged use of such engines and the operation of future GEO satellites lead to a renewed interest in large, deployable and ultra-lightweight power generators in space. Within the GoSolAr (Gossamer Solar Array) activity, DLR develops a new photovoltaic array technology for power generation. It is based on the DLR Gossamer approach using lightweight, deployable CFRP booms and a membrane consisting of thin-film CIGS photovoltaics generators and the necessary power harness. The booms are arranged in a crossed configuration with a cen-tral deployment unit. The photovoltaic area is composed of one large square membrane with double folding using two-dimensional deployment. Even though the efficiency of thin-film photovoltaics is currently only about 1/3 of that of con-ventional photovoltaics, a membrane based array can already equal or achieve better mass/power ratios. A 50 kW array requires an area of approximately 20 m x 20 m. In a first step, DLR devel-ops a fully functional 5 m x 5 m demonstrator partially covered with thin-film photovoltaics and considering scalability aspects. Space compatible thin-film photovoltaics need to be selected and tested. They are integrated on standardized generator modules that will be assembled into a large, foldable and deployable membrane. A controlled deployment of structure and membrane, and a sufficiently stiff support structure for operation are key development topics. We present the conceptual design of the GoSolAr deployment demonstrator, the main require-ments, preliminary technical budgets, the development strategy and first experimental results. An overview will be given on the selection and the maturity of the key technologies and subsystems, such as deployable membrane with integrated photovoltaic generators; deployable CFRP booms including deployment mechanisms as well as electronics concept for operation and photovoltaics characterization. Furthermore, an overview of the first manufactured breadboard models and their testing will be presented, e.g. combined testing of booms and mechanically representative generator arrays to evaluate deployment and interface forces for the preliminary design

    GOSOLAR A GOSSAMER SOLAR ARRAY CONCEPT FOR HIGH POWER SPACECRAFT APPLICATIONS USING FLEXIBLE THIN-FILM PHOTOVOLTAICS

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    The power demand for future satellite applications will continue to rise. Geostationary telecommunication satellites currently approach a power level of up to 20 kW. Future spacecraft will provide yet more transponders and/or direct mobile-satellite services. Electric propulsion is in-creasingly used for station keeping, attitude control and GEO circularization. Interplanetary mis-sions already use kW-range electric propulsion. Space Tugs are studied for several fields. Suitable engines require 100 kW or more. The envisaged use of such engines and the operation of future GEO satellites lead to a renewed interest in large, deployable and ultra-lightweight power generators in space. Within the GoSolAr (Gossamer Solar Array) activity, DLR develops a new photovoltaic array technology for power generation. It is based on the DLR Gossamer approach using lightweight, deployable CFRP booms and a polymer membrane covered with thin-film CIGS photovoltaics. The booms are arranged in a crossed configuration with a central deployment unit. The photovol-taic area is composed of one large square membrane with double folding using two-dimensional deployment. Even though the efficiency of thin-film photovoltaics is currently only about 1/3 of that of con-ventional photovoltaics, a membrane based array can already achieve better mass/power ratios. A 50 kW array requires an area of approximately 20 m x 20 m. In a first step, DLR develops a fully functional 5 m x 5 m demonstrator partially covered with thin-film photovoltaics, using the DLR small satellite platform S2TEP. Space compatible thin-film photovoltaics need to be select-ed and tested. They are integrated on standardized generator modules that will be assembled into a large, foldable and deployable membrane. A controlled deployment of structure and membrane, and a sufficiently stiff support structure for operation are key development topics. We present the conceptual design of the GoSolAr demonstrator, the main requirements, preliminary technical budgets and the development strategy. An overview will be given on the selection and the maturity of the key technologies and subsystems, such as deployable membrane with in-tegrated photovoltaic generators; deployable CFRP booms including deployment mechanisms; photovoltaic cell selection and integration to generator units; the array harness concept as well as the electronics concept, for operation and photovoltaics characterization. Furthermore, an over-view of the first manufactured breadboard models and their testing will be presented, e.g. com-bined testing of booms and mechanically representative generator arrays to evaluate deployment and interface forces for the preliminary design

    GoSolAr – A Gossamer Solar Array Concept for High Power Spacecraft Applications using flexible Photovoltaics

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    The power demand for future satellite applications will continue to rise. Geostationary telecom-munication satellites currently approach a power level of up to 20 kW. Future spacecraft will provide yet more transponders and/or direct mobile-satellite services. Electric propulsion is in-creasingly used for station keeping, attitude control and GEO circularization. Interplanetary mis-sions already use kW-range electric propulsion. Space Tugs are studied for several fields. Suitable engines require 100 kW or more. The envisaged use of such engines and the operation of future GEO satellites lead to a renewed interest in large, deployable and ultra-lightweight power gen-erators in space. Within the GoSolAr (Gossamer Solar Array) activity, DLR develops a new photovoltaic array technology for power generation. It is based on the DLR Gossamer approach using lightweight, deployable CFRP booms and a polymer membrane covered with thin-film CIGS photovoltaics. The booms are arranged in a crossed configuration with a central deployment unit. The photovol-taic area is composed of one large square membrane with double folding using two-dimensional deployment. Even though the efficiency of thin-film photovoltaics is currently only about 1/3 of that of con-ventional photovoltaics, a membrane based array can already achieve better mass/power ratios. A 50 kW array requires an area of approximately 20 m x 20 m. In a first step, DLR develops a fully functional 5 m x 5 m demonstrator partially covered with thin-film photovoltaics, using the DLR small satellite platform S2TEP. Space compatible thin-film photovoltaics need to be select-ed and tested. They are integrated on standardized generator modules that will be assembled into a large, foldable and deployable membrane. A controlled deployment of structure and membrane, and a sufficiently stiff support structure for operation are key development topics. We present the conceptual design of the GoSolAr demonstrator, the main requirements, prelimi-nary technical budgets and the development strategy. An overview will be given on the selection and the maturity of the key technologies and subsystems, such as deployable membrane with in-tegrated photovoltaic generators; deployable CFRP booms including deployment mechanisms; photovoltaic cell selection and integration to generator units; the array harness concept as well as the electronics concept, for operation and photovoltaics characterization. Furthermore, an over-view of the first manufactured breadboard models and their testing will be presented, e.g. com-bined testing of booms and mechanically representative generator arrays to evaluate deployment and interface forces for the preliminary design
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