752 research outputs found

    Inductive Low‐Frequency Processes in PEMFC‐Impedance Spectra

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    African peasants on the move: turmoil between global dynamics, migration and food insecurity

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    This issue presents some of the publications resulting from the research project “African societies facing global dynamics: Turbulences between external intervention, migration, and food insecurity” [Dynamics]1. The underlying idea was to investigate contemporary global dynamics faced by African societies, how they interact with internal processes of change and these societies’ responses to these pressures. The contributions address the key issues raised in the Dynamics research project in different ways. They focus on an analysis of migration (internal as well as international), agricultural transformation and food (in)security in different societies and locations. They also explore the links between them and their interrelations with global dynamics. The work was based on case studies conducted in Guinea-Bissau, São Tomé and Príncipe (STP), Cape Verde and Senegal. An additional contribution from Mozambique was also included as it addressed the central issues of the project. Although this research project in itself can only address a few aspects of this complex set of interactions and highlight some of the key issues at play in specific case studies, the project is part of a long-term investigation about the dynamics of change in African agrarian societies which contemplates a wider range of issues.info:eu-repo/semantics/publishedVersio

    Offline digital – digital offline: The potential of offline digitised information for the production, distribution and appropriation of human knowledge

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    The lifeworlds of large parts of the human population have undergone profound transformations through the expansion of the internet. Yet great parts of the world are still totally or partially offline. Cheap smartphones, tablets and (off-grid) electricity reach ever more of these populations. Scientists’ fascination with the internet – where money, investments, business models, communication, political control, as well as their lifeworlds converge - has largely obscured the potential of offline digitised information for the storage and distribution of information and the appropriation of knowledge. The profound changes of the socialisation of human knowledge through the revolutions in the transmission media have influenced how societies produce, distribute, receive and appropriate information. The expansion of access to digitised information revolutionises horizontal and vertical transmission. The differences are manifold: physical requirements are reduced – a whole library fits into a pocket; digital information is much cheaper to acquire; logistic chains through which books or journals are produced, shipped, distributed and stored are as unnecessary as are libraries. The actual access to information is also vastly different – the electronic search function and the offline Wikipedia may serve as examples. This suggests a rethinking of the “digital divide” which is no longer synonymous with internet access. Is there rather a frontier zone where different forms of access overlap? What are the distribution and market mechanisms for offline digital information? To what uses can digitised information be put offline? How will the new availability of ever cheaper technology affect knowledge production and appropriation?info:eu-repo/semantics/publishedVersio

    Saudações em África - Além do aperto de mão: Um ensaio sobre os rituais de saudação e despedida como prática de comunicação em sociedades agrárias da África Subsaariana

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    In African Agrarian Societies greeting and leave-taking rituals are an essential part of the communication processes that constitute these societies as collective entities. Through elaborate forms of greeting and leave-taking people initiate and end communication and interaction processes within a framework of collective identities and cultures. Intricate greeting rituals allow to deal with all forms of encounters, with living people as well as with the spirits of the deceased. Greeting rituals are acquired through lengthy periods of learning. Their mastery is the sign of being an adult and competent member of society. External actors from different cultures often seem to be unaware of the subtleties of these greeting rituals. They ignore them at a cost. This essay provides some insights into the inner workings of African societies concerning the framing of most of their internal and external communication processes that are as vital for their lifeworlds as they are for their interaction with external actors from different spheres. Analysing the societies in a comprehensive manner as self-organising entities within an ethnic matrix clearly shows the limits of reducing greeting rituals to mere speech acts between individuals and proves that some of the fundamental assumptions of modern communication theories are not valid for African Agrarian Societies.info:eu-repo/semantics/publishedVersio

    Simulating Business Process Scenarios for Event-Based Systems

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    PaaSword: A Holistic Data Privacy and Security by Design Framework for Cloud Services

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    Enterprises increasingly recognize the compelling economic and operational benefits from virtualizing and pooling IT resources in the cloud. Nevertheless, the significant and valuable transformation of organizations that adopt cloud computing is accompanied by a number of security threats that should be considered. In this position paper, we outline significant security challenges presented when migrating to a cloud environment and propose PaaSword - a novel holistic framework that aspires to alleviate these challenges. Specifically, this proposed framework involves a context-aware security model, the necessary policies enforcement mechanism along with a physical distribution, encryption and query middleware

    Epistemic Beliefs in Science—A Systematic Integration of Evidence From Multiple Studies

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    Recent research has integrated developmental and dimensional perspectives on epistemic beliefs by implementing an approach in which profiles of learners’ epistemic beliefs are modeled across multiple dimensions. Variability in study characteristics has impeded the comparison of profiles of epistemic beliefs and their relations with external variables across studies. We examined this comparability by integrating data on epistemic beliefs about the source, certainty, development, and justification of knowledge in science from six studies comprising N = 10,932 German students from elementary to upper secondary school. Applying latent profile analyses to these data, we found that profiles of epistemic beliefs that were previously conceptualized were robust across multiple samples. We found indications that profiles of epistemic beliefs homogenize over the course of students’ education, are related to school tracking, and demonstrate robust relations with students’ personal characteristics and socioeconomic background. We discuss implications for the theory, assessment, and education of epistemic beliefs. © 2022, The Author(s)

    Temporal modulation of the response of sensory fibers to paired-pulse stimulation

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    Multi-channel nerve cuff electrode arrays can provide sensory feedback to prosthesis users. To develop efficacious stimulation protocols, an understanding of the impact that spatio-temporal patterned stimulation can have on the response of sensory fibers is crucial. We used experimental and modelling methods to investigate the response of nerve fibers to paired-pulse stimulation. Nerve cuff electrode arrays were implanted for stimulation of the sciatic nerves of rats and the sensory compound action potentials were recorded from the L4 dorsal root. A model of the nerve cuff electrode array and sciatic nerve was also developed. The experimental and modelling results were compared. Experiments showed that it took 8 ms for the sensory fibers to completely recover from a conditioning stimulus, regardless of the relative position of the electrodes used for stimulation. The results demonstrate that the electrodes on the cuff cannot be considered independent. Additionally, at 120% of the threshold, there is a large overlap in the fibers that were activated by the different electrodes. If a stimulus paradigm considered the electrodes as independent, stimuli from the different electrodes would need to be interleaved, and the intervals between the stimuli should be greater than 8 ms
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