6,916 research outputs found

    The omnivorous Tyrolean Iceman: colon contents (meat, cereals, pollen, moss and whipworm) and stable isotope analyses

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    The contents of the colon of the Tyrolean Iceman who lived Ga. 5300 years ago include muscle fibres, cereal remains, a diversity of pollen, and most notably that of the hop hornbeam (Ostrya carpinifolia) retaining cellular contents, as well as a moss leaf (Neckera complanata) and eggs of the parasitic whipworm (Trichuris trichiura). Based almost solely on stable isotope analyses and ignoring the work on the colon contents, two recently published papers on the Iceman's diet draw ill- founded conclusions about vegetarianism and even veganism. Neither the pollen nor the moss is likely to have been deliberately consumed as food by the Iceman. All the available evidence concerning the Iceman's broad-based diet is reviewed and the significance of the colon contents for matters other than assessment of food intake is outlined

    Developing the role concept for computer-supported collaborative learning

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    The role concept has attracted a lot of attention as a construct for facilitating and analysing interactions in the context of Computer-Supported Collaborative Learning (CSCL). So far much of this research has been carried out in isolation and the focus on roles lacks cohesion. In this article we present a conceptual framework to synthesise the contemporary conceptualisation of roles, by discerning three levels of the role concept: micro (role as task), meso (role as pattern) and macro (role as stance). As a first step to further conceptualise ‘role as a stance’, we present a framework of eight participative stances defined along three dimensions: group size, orientation and effort. The participative stances – Captain, Over-rider, Free-rider, Ghost, Pillar, Generator, Hanger-on and Lurker – were scrutinised on two data sets using qualitative analysis. The stances aim to facilitate meaningful description of student behaviour, stimulate both teacher and student awareness of roles at the macro-level in terms of participative stances, and evaluate or possibly change the participation to collaborative learning on all levels

    Analytic calculation of radio emission from parametrized extensive air showers:A tool to extract shower parameters

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    The radio intensity and polarization footprint of a cosmic-ray induced extensive air shower is determined by the time-dependent structure of the current distribution residing in the plasma cloud at the shower front. In turn, the time dependence of the integrated charge-current distribution in the plasma cloud, the longitudinal shower structure, is determined by interesting physics which one would like to extract, such as the location and multiplicity of the primary cosmic-ray collision or the values of electric fields in the atmosphere during thunderstorms. To extract the structure of a shower from its footprint requires solving a complicated inverse problem. For this purposewe have developed a code that semianalytically calculates the radio footprint of an extensive air shower given an arbitrary longitudinal structure. This code can be used in an optimization procedure to extract the optimal longitudinal shower structure given a radio footprint. On the basis of air-shower universality we propose a simple parametrization of the structure of the plasma cloud. This parametrization is based on the results of Monte Carlo shower simulations. Deriving the parametrization also teaches which aspects of the plasma cloud are important for understanding the features seen in the radio-emission footprint. The calculated radio footprints are compared with microscopic CoREAS simulations

    Conceptual framework for social connectedness in mental disorders: systematic review and narrative synthesis

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    Background: Adults with mental disorders are at high risk of loneliness. Loneliness has been implicated in a wide variety of physical and mental health problems. Social connectedness interventions are one means to tackle loneliness but have shown mixed effectiveness. This study aims to: (1) identify existing measures of social connectedness and (2) develop a conceptual framework of social connectedness to inform future measurement and the development of new interventions.Methods: A systematic review of studies from six bibliographic databases was conducted. Studies were included if a quantitative measure of social connectedness was used amongst samples of adults with a mental disorder. Two analyses were conducted: a best evidence synthesis of measurement properties for identified measures and a narrative synthesis of items from these measures.Results: Twenty-eight papers were included, employing 22 different measures. Measurement properties were of poor or unknown quality. Data synthesis identified a five-dimension conceptual framework of social connectedness: Closeness, Identity and common bond, Valued relationships, Involvement and Cared for and accepted (giving the acronym CIVIC).Limitations: The majority of studies were conducted in high-income countries. It was not possible to validate the conceptual framework using the identified psychometric data.Conclusions: This new five-dimension framework of social connectedness in mental disorders provides the theoretical foundation for developing new measures and interventions for social connectedness

    Economic choices can be made using only stimulus values

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    Decision-making often involves choices between different stimuli, each of which is associated with a different physical action. A growing consensus suggests that the brain makes such decisions by assigning a value to each available option and then comparing them to make a choice. An open question in decision neuroscience is whether the brain computes these choices by comparing the values of stimuli directly in goods space or instead by first assigning values to the associated actions and then making a choice over actions. We used a functional MRI paradigm in which human subjects made choices between different stimuli with and without knowledge of the actions required to obtain the different stimuli. We found neural correlates of the value of the chosen stimulus (a postdecision signal) in ventromedial prefrontal cortex before the actual stimulus–action pairing was revealed. These findings provide support for the hypothesis that the brain is capable of making choices in the space of goods without first transferring values into action space

    Structural organisation of the type IV secretion systems

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    Type IV secretion (T4S) systems are large dynamic nanomachines that transport DNAs and/or proteins through the membranes of bacteria. Because of their complexity and multi-protein organisation, T4S systems have been extremely challenging to study structurally. However in the past five years significant milestones have been achieved by X-ray crystallography and cryo-electron microscopy. This review describes some of the more recent advances: the structures of some of the protein components of the T4S systems and the complete core complex structure that was determined using electron microscopy

    φxANES: In vivo imaging of metal-protein coordination environments

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    © 2016, Nature Publishing Group. All rights reserved. We have developed an X-ray absorption near edge structure spectroscopy method using fluorescence detection for visualizing in vivo coordination environments of metals in biological specimens. This approach, which we term fluorescence imaging XANES (φXANES), allows us to spatially depict metal-protein associations in a native, hydrated state whilst avoiding intrinsic chemical damage from radiation. This method was validated using iron-challenged Caenorhabditis elegans to observe marked alterations in redox environment

    Emerging and scripted roles in computer-supported collaborative learning

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    Emerging and scripted roles pose an intriguing approach to analysing and facilitating CSCL. The concept of emerging roles provides a perspective on how learners structure and self-regulate their CSCL processes. Emerging roles appear to be dynamic over longer periods of time in relation to learners’ advancing knowledge, but are often unequally distributed in ad hoc CSCL settings, e.g. a learner being the ‘typist’ and another being the ‘thinker’. Empirical findings show that learners benefit from structuring or scripting CSCL. Scripts can specify roles and facilitate role rotation for learners to equally engage in relevant learning roles and activities. Scripted roles can, however, collide with emerging roles and therefore need to be carefully attuned to the advancing capabilities of the learners

    Dogs in society can prevent society going to the dogs

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    An editorial comment on the importance of dogs to society, to counter the emphasis given to the risks they pose
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