6,574 research outputs found

    The Globalization of Artificial Intelligence: African Imaginaries of Technoscientific Futures

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    Imaginaries of artificial intelligence (AI) have transcended geographies of the Global North and become increasingly entangled with narratives of economic growth, progress, and modernity in Africa. This raises several issues such as the entanglement of AI with global technoscientific capitalism and its impact on the dissemination of AI in Africa. The lack of African perspectives on the development of AI exacerbates concerns of raciality and inclusion in the scientific research, circulation, and adoption of AI. My argument in this dissertation is that innovation in AI, in both its sociotechnical imaginaries and political economies, excludes marginalized countries, nations and communities in ways that not only bar their participation in the reception of AI, but also as being part and parcel of its creation. Underpinned by decolonial thinking, and perspectives from science and technology studies and African studies, this dissertation looks at how AI is reconfiguring the debate about development and modernization in Africa and the implications for local sociotechnical practices of AI innovation and governance. I examined AI in international development and industry across Kenya, Ghana, and Nigeria, by tracing Canada’s AI4D Africa program and following AI start-ups at AfriLabs. I used multi-sited case studies and discourse analysis to examine the data collected from interviews, participant observations, and documents. In the empirical chapters, I first examine how local actors understand the notion of decolonizing AI and show that it has become a sociotechnical imaginary. I then investigate the political economy of AI in Africa and argue that despite Western efforts to integrate the African AI ecosystem globally, the AI epistemic communities in the continent continue to be excluded from dominant AI innovation spaces. Finally, I examine the emergence of a Pan-African AI imaginary and argue that AI governance can be understood as a state-building experiment in post-colonial Africa. The main issue at stake is that the lack of African perspectives in AI leads to negative impacts on innovation and limits the fair distribution of the benefits of AI across nations, countries, and communities, while at the same time excludes globally marginalized epistemic communities from the imagination and creation of AI

    Boundary Spanner Corruption in Business Relationships

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    Boundary spanner corruption—voluntary collaborative behaviour between individuals representing different organisations that violates their organisations’ norms—is a serious problem in business relationships. Drawing on insights from the literatures on general corruption perspectives, the dark side of business relationships and deviance in sales and service organisations, this dissertation identifies boundary spanner corruption as a potential dark side complication inherent in close business relationships It builds research questions from these literature streams and proposes a research structure based upon commonly used methods in corruption research to address this new concept. In the first study, using an exploratory survey of boundary spanner practitioners, the dissertation finds that the nature of boundary spanner corruption is broad and encompasses severe and non-severe types. The survey also finds that these deviance types are prevalent in a widespread of geographies and industries. This prevalence is particularly noticeable for less-severe corruption types, which may be an under-researched phenomenon in general corruption research. The consequences of boundary spanner corruption can be serious for both individuals and organisations. Indeed, even less-severe types can generate long-term negative consequences. A second interview-based study found that multi-level trust factors could also motivate the emergence of boundary spanner corruption. This was integrated into a theoretical model that illustrates how trust at the interpersonal, intraorganisational, and interorganisational levels enables corrupt behaviours by allowing deviance-inducing factors stemming from the task environment or from the individual boundary spanner to manifest in boundary spanner corruption. Interpersonal trust between representatives of different organisations, interorganisational trust between these organisations, and intraorganisational agency trust of management in their representatives foster the development of a boundary-spanning social cocoon—a mechanism that can inculcate deviant norms leading to corrupt behaviour. This conceptualisation and model of boundary spanner corruption highlights intriguing directions for future research to support practitioners engaged in a difficult problem in business relationships

    Study of neural circuits using multielectrode arrays in movement disorders

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    Treballs Finals de Grau d'Enginyeria Biomèdica. Facultat de Medicina i Ciències de la Salut. Universitat de Barcelona. Curs: 2022-2023. Tutor/Director: Rodríguez Allué, Manuel JoséNeurodegenerative movement-related disorders are characterized by a progressive degeneration and loss of neurons, which lead to motor control impairment. Although the precise mechanisms underlying these conditions are still unknown, an increasing number of studies point towards the analysis of neural networks and functional connectivity to unravel novel insights. The main objective of this work is to understand cellular mechanisms related to dysregulated motor control symptoms in movement disorders, such as Chorea-Acanthocytosis (ChAc), by employing multielectrode arrays to analyze the electrical activity of neuronal networks in mouse models. We found no notable differences in cell viability between neurons with and without VPS13A knockdown, that is the only gene known to be implicated in the disease, suggesting that the absence of VPS13A in neurons may be partially compensated by other proteins. The MEA setup used to capture the electrical activity from neuron primary cultures is described in detail, pointing out its specific characteristics. At last, we present the alternative backup approach implemented to overcome the challenges faced during the research process and to explore the advanced algorithms for signal processing and analysis. In this report, we present a thorough account of the conception and implementation of our research, outlining the multiple limitations that have been encountered all along the course of the project. We provide a detailed analysis on the project’s economical and technical feasibility, as well as a comprehensive overview of the ethical and legal aspects considered during the execution

    Memory Effects, Multiple Time Scales and Local Stability in Langevin Models of the S&P500 Market Correlation

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    The analysis of market correlations is crucial for optimal portfolio selection of correlated assets, but their memory effects have often been neglected. In this work, we analyse the mean market correlation of the S&P500 which corresponds to the main market mode in principle component analysis. We fit a generalised Langevin equation (GLE) to the data whose memory kernel implies that there is a significant memory effect in the market correlation ranging back at least three trading weeks. The memory kernel improves the forecasting accuracy of the GLE compared to models without memory and hence, such a memory effect has to be taken into account for optimal portfolio selection to minimise risk or for predicting future correlations. Moreover, a Bayesian resilience estimation provides further evidence for non-Markovianity in the data and suggests the existence of a hidden slow time scale that operates on much slower times than the observed daily market data. Assuming that such a slow time scale exists, our work supports previous research on the existence of locally stable market states.Comment: 15 pages (excluding references and appendix

    Facilitating prosociality through technology: Design to promote digital volunteerism

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    Volunteerism covers many activities involving no financial rewards for volunteers but which contribute to the common good. There is existing work in designing technology for volunteerism in HumanComputer Interaction (HCI) and related disciplines that focuses on motivation to improve performance, but it does not account for volunteer wellbeing. Here, I investigate digital volunteerism in three case studies with a focus on volunteer motivation, engagement, and wellbeing. My research involved volunteers and others in the volunteering context to generate recommendations for a volunteer-centric design for digital volunteerism. The thesis has three aims: 1. To investigate motivational aspects critical for enhancing digital volunteers’ experiences 2. To identify digital platform attributes linked to volunteer wellbeing 3. To create guidelines for effectively supporting volunteer engagement in digital volunteering platforms In the first case study I investigate the design of a chat widget for volunteers working in an organisation with a view to develop a design that improves their workflow and wellbeing. The second case study investigates the needs, motivations, and wellbeing of volunteers who help medical students improve their medical communication skills. An initial mixed-methods study was followed by an experiment comparing two design strategies to improve volunteer relatedness; an important indicator of wellbeing. The third case study looks into volunteer needs, experiences, motivations, and wellbeing with a focus on volunteer identity and meaning-making on a science-based research platform. I then analyse my findings from these case studies using the lens of care ethics to derive critical insights for design. The key contributions of this thesis are design strategies and critical insights, and a volunteer-centric design framework to enhance the motivation, wellbeing and engagement of digital volunteers

    Inovação, empreendedorismo e desenvolvimento económico em África: Uma abordagem pós-positivista e "topo da pirâmide" para Moçambique

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    Esta tese desenvolve uma investigação abrangente sobre o empreendedorismo africano, revisitando o seu quadro concetual tradicional e posicionando-o enquanto elemento fundamental das estratégias de desenvolvimento para a África Subsariana (ASS). Explorados os diferentes impactos do empreendedorismo de oportunidade e do empreendedorismo de necessidade na região, efetuou-se uma pesquisa sobre a situação dos vários países da ASS que participaram no Global Entrepreneurship Monitor na última década, com vista a compor o status quo hipotético do empreendedorismo regional, ao qual juntámos um estudo empírico original e com elementos metodológicos inovadores sobre a atividade empreendedora em Moçambique. O alcance das estratégias empreendedoras implementadas na ASS é avaliado através de um estudo dos polos africanos de inovação tecnológica e do empreendedorismo digital que neles tem vindo recentemente a emergir, a que juntámos um levantamento original do tech hub de Maluana. Por fim, a partir destes casos e de uma leitura política das opções económicas do estado moçambicano com impacto sobre o ecossistema empreendedor, desenvolve-se uma proposta de teoria da mudança, numa lógica pós-positivista, para suportar medidas de política pública desejáveis para a eclosão de um empreendedorismo de “topo da pirâmide” em Moçambique.This thesis develops a comprehensive investigation of African entrepreneurship, revisiting its traditional conceptual framework and positioning it as a fundamental element in development strategies for Sub-Saharan Africa (SSA). Exploring the different impacts of opportunity entrepreneurship and necessity entrepreneurship in the region, an analysis was carried out on the situation of the various SSA countries that participated in the Global Entrepreneurship Monitor in the last decade, with a view to composing the hypothetical status quo of the entrepreneurship in the region, to which we added an original empirical study with innovative methodological elements on entrepreneurial activity in Mozambique. The reach of entrepreneurial strategies implemented in the SSA is assessed through a study of the African tech hubs, or innovation hubs, and the digital entrepreneurship that has recently emerged there, to which we have added an original survey of the Maluana tech hub. Finally, based on these cases and on a political reading of the economic options of the Mozambican government with an impact on the entrepreneurial ecosystem, a proposal for a theory-of-change is developed, within a post-positivist approach, to support desired public policy measures for the emergence of a “top of the pyramid” entrepreneurship in Mozambique

    OLIG2 neural progenitor cell development and fate in Down syndrome

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    Down syndrome (DS) is caused by triplication of human chromosome 21 (HSA21) and is the most common genetic form of intellectual disability. It is unknown precisely how triplication of HSA21 results in the intellectual disability, but it is thought that the global transcriptional dysregulation caused by trisomy 21 perturbs multiple aspects of neurodevelopment that cumulatively contribute to its etiology. While the characteristics associated with DS can arise from any of the genes triplicated on HSA21, in this work we focus on oligodendrocyte transcription factor 2 (OLIG2). The progeny of neural progenitor cells (NPCs) expressing OLIG2 are likely to be involved in many of the cellular changes underlying the intellectual disability in DS. To explore the fate of OLIG2+ neural progenitors, we took advantage of two distinct models of DS, the Ts65Dn mouse model and induced pluripotent stem cells (iPSCs) derived from individuals with DS. Our results from these two systems identified multiple perturbations in development in the cellular progeny of OLIG2+ NPCs. In Ts65Dn, we identified alterations in neurons and glia derived from the OLIG2 expressing progenitor domain in the ventral spinal cord. There were significant differences in the number of motor neurons and interneurons present in the trisomic lumbar spinal cord depending on age of the animal pointing both to a neurodevelopment and a neurodegeneration phenotype in the Ts65Dn mice. Of particular note, we identified changes in oligodendrocyte (OL) maturation in the trisomic mice that are dependent on spatial location and developmental origin. In the dorsal corticospinal tract, there were significantly fewer mature OLs in the trisomic mice, and in the lateral funiculus we observed the opposite phenotype with more mature OLs being present in the trisomic animals. We then transitioned our studies into iPSCs where we were able to pattern OLIG2+ NPCs to either a spinal cord-like or a brain-like identity and study the OL lineage that differentiated from each progenitor pool. Similar to the region-specific dysregulation found in the Ts65Dn spinal cord, we identified perturbations in trisomic OLs that were dependent on whether the NPCs had been patterned to a brain-like or spinal cord-like fate. In the spinal cord-like NPCs, there was no difference in the proportion of cells expressing either OLIG2 or NKX2.2, the two transcription factors whose co-expression is essential for OL differentiation. Conversely, in the brain-like NPCs, there was a significant increase in OLIG2+ cells in the trisomic culture and a decrease in NKX2.2 mRNA expression. We identified a sonic hedgehog (SHH) signaling based mechanism underlying these changes in OLIG2 and NKX2.2 expression in the brain-like NPCs and normalized the proportion of trisomic cells expressing the transcription factors to euploid levels by modulating the activity of the SHH pathway. Finally, we continued the differentiation of the brain-like and spinal cord-like NPCs to committed OL precursor cells (OPCs) and allowed them to mature. We identified an increase in OPC production in the spinal cord-like trisomic culture which was not present in the brain-like OPCs. Conversely, we identified a maturation deficit in the brain-like trisomic OLs that was not present in the spinal cord-like OPCs. These results underscore the importance of regional patterning in characterizing changes in cell differentiation and fate in DS. Together, the findings presented in this work contribute to the understanding of the cellular and molecular etiology of the intellectual disability in DS and in particular the contribution of cells differentiated from OLIG2+ progenitors

    Towards personalized immunotherapy : development of in vitro models for imaging natural killer cell behavior in the tumor microenvironment

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    Tremendous advances in the tumor immunology field have transformed immunotherapy from a promising approach to a standard clinical practice. However, a subset of cancer patients is non-responsive to immunotherapy. More research is therefore needed to understand the mechanisms underlying tumor resistance to immunotherapeutic treatments. The aim of this doctoral work was to develop new tools to study the mechanisms of cancer immunosurveillance and to test immunotherapeutic treatments in vitro. In this thesis, I describe the methods developed, and I discuss the main biological findings obtained by using these methods. The thesis is organized as follows. A short historical background of immunotherapy is provided in Chapter 1. Chapter 2 describes the principles of NK cell-mediated cancer immunosurveillance, and provides an overview on rare cancers, mainly focusing on sarcoma. The research aims are listed in Chapter 3. In Chapter 4, I describe the cell culture methods and cell analysis techniques relevant for my doctoral work. In Chapter 5, I describe the methods we developed to culture tumor spheroids in vitro using ultrasonic standing waves in microwell chips, focusing on the theory, design, and applications. Chapter 6 and Chapter 7 focus on the biological findings obtained using our platform in combination with traditional immunological methods, followed by future implementations discussed in Chapter 8. The constituent papers are provided at the end of the thesis. In Paper I, we combined the use of the microwell chip, ultrasonic standing waves and a protein-repellent polymer coating to enable the production of spheroids from multiple cell types. In absence of cell adhesion to the chip, spheroids could be collected and further analyzed by off-the-chip techniques. In Paper II, we designed a novel multichambered microwell chip to perform multiplexed fluorescence screening of two- or three-dimensional cell cultures. The platform allows the direct assessment of drug or immune cell cytotoxic efficacy, making it a promising tool for individualized cytotoxicity tests for personalized medicine. In Paper III, we investigate the function of PVR receptors in NK cells interacting with renal carcinoma spheroids, and the impact of PVR in NK cell-based cellular immunotherapy. We demonstrated that variations in PVR expression are primarily recognized by the inhibitory receptor TIGIT, while DNAM-1 strongly contributes to NK cell activation mainly through PVR-independent mechanisms. We performed NK cell-based cytotoxicity assays against renal carcinoma spheroids in the microwell chip. Anti-TIGIT treatment was effective only for TIGIThigh NK cells both when used as monotherapy or in combination with other drugs, suggesting that only a fraction of patients might respond to anti-TIGIT therapy. In Paper IV, a similar approach was used with primary sarcomas. We cultured patient-derived sarcoma spheroids and tested NK cell-based immunotherapy in the microwell chip, either alone or in combination with antibody therapy, and we identified promising treatment combinations. In Paper V, we applied the use of expansion microscopy to visualize NK cells infiltrating renal carcinoma spheroids. In conclusion, our multi-disciplinary work shows the development of new imaging-based platform and its use to study the mechanisms of NK cell-mediated tumor surveillance and for personalized therapy

    Using Simulation in Information Systems Research

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    Like all other scientific research methodologies, simulation has its strengths and limitations. When used properly, simulation can be a powerful tool for developing new theoretical insights into IS phenomena of interest. Although simulation methods are not new in the IS field, there has been no systematic discussion about which simulation methods are suitable for IS research, when simulation is the most appropriate methodological choice for IS research, and how to evaluate simulation research. In this editorial, I provide an overview of simulation methods that may be used in IS research and discuss how they are typically used. More importantly, I provide guidelines for IS researchers on how to choose simulation among alternative methodologies and highlight six key criteria for evaluating simulation research. Overall, this editorial can provide useful guidance to IS researchers, editors, and reviewers when choosing, conducting, and assessing simulation research

    Influence of newly-synthesized chalcone derivatives on growth, biofilm production, and virulence factors expression of multiresistant Acinetobacter baumannii strains

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    Acinetobacter baumannii je nozokomijalni, multirezistentni patogen, koga karakterišesposobnost perzistencije na neživim površinama i mogućnost veoma brzog sticanja rezistencije naantibiotike. Danas su u svetu rasprostranjeni izrazito rezistentni sojevi protiv kojih u mnogimzdravstvenim ustanovama ne postoji efikasna terapija, a pronalazak alternativnih terapijskihpristupa je od izuzetne važnosti. Halkoni su jedinjenja sa potvrđenim antimikrobnim svojstvima ipokazanim različitim antivirulentnim aktivnostima. Ciljevi istraživanja ovog rada bili suodređivanje profila rezistencije, ispitivanje mogućnosti kontaminacije antiseptika i ispitivanjeprodukcije biofilma identifikovanih kliničkih izolata A. baumannii, kao i sinteza derivatahidroksihalkona i ispitivanje njihovih antimikrobnih i antivirulentnih aktivnosti protiv ovih izolata.Osetljivost izolata na antibiotike ispitana je kombinacijom difuzionih, dilucionih iautomatizovanih metoda, a identifikovani kolistin-rezistentni izolati dodatno su podvrgnutisekvenciranju celog genoma (WGS) i genetički su okarakterisani. Takođe, mehanizmi rezistencijena kolistin ispitani su primenom komparativne analize genoma i Real-Time kvantitativne lančanereakcije polimeraze (RT-qPCR). Time-kill test je primenjen za ispitivanje perzistencije uantisepticima, a nivo produkcije biofilma ispitan je pod različitim uslovima kultivacije in vitrostatičkom metodom uz bojenje safraninom. Derivati hidroksihalkona sintetisani su pomoću Claisen-Schmidt kondenzacije i njihove antimikrobne aktivnosti, samih i u kombinaciji sa antibioticima,ispitane su bujon-mikrodilucionom, Time-kill i Checkerboard analizom. Antivirulentne aktivnostiodabranih halkona procenjene su posredstvom uticaja na produkciju biofilma (monomikrobnog ipolimikrobnog), vijabilnost biofilmskih ćelija, ekspresiju motiliteta, gensku ekspresiju faktoravirulencije (OmpA, Bap i AbaI), adheziju A. baumannii na komponente ekstracelularnog matriksa(ECM), kao što su fibronektin i kolagen, i aktivnost sistema međućelijske komunikacije (Quorum-Sensing, QS).Klinički izolati A. baumannii gotovo uniformno bili su rezistentni na karbapeneme, a čakskoro 19% izolata bilo je rezistentno na kolistin, pripadajući tako ekstenzivno rezistentnom ilipanrezistentnom fenotipu. Izolati su pokazali sposobnost kontaminacije antiseptika i produkcijevelikih količina biofilma. Nutritivni sastav hranljivih medijuma značajno je uticao na nivoprodukcije biofilma, dok se visok nivo produkcije održao pri širokom opsegu različitih temperaturainkubacije i u prisustvu subinhibitornih koncentracija antibiotika. Sintetisani halkoni ispoljili suumerenu antimikrobnu aktivnost, pri čemu su metoksi-supstituisani derivati u proseku najjačeinhibirali rast. Takođe, zabeleženo je nekoliko sinergističkih interakcija halkona sa meropenemom,a inhibicija efluksnih pumpi predložena je kao potencijalni mehanizam. Halkoni su pokazalisposobnost značajne inhibicije motiliteta i produkcije biofilma, a metoksi-supstituisani derivat (o-OCH3) ispoljio je značajnu antivirulentnu aktivnost posredstvom nishodne regulacije ekspresijeompA, bap i abaI gena i inhibicije adhezije na komponente ECM. Na osnovu ovih rezultata, o-OCH3 halkon je identifikovan kao potentni antivirulentni agens protiv A. baumannii.Acinetobacter baumannii is a nosocomial, multiresistant pathogen, able to persist on abioticsurfaces and to rapidly acquire antibiotic resistance. Nowadays, highly resistant strains are widelydisseminated throughout the world, and the discovery of alternative therapeutic strategies is of utterimportance. Chalcones are compounds whose antimicrobial properties are well-known and forwhich different antivirulence activities have been demonstrated. The aims of this research were todetermine resistance profiles, to evaluate the possibility of antiseptic contamination, and to analyzethe biofilm production of identified A. baumannii clinical isolates, as well as to synthesizehydroxychalcone derivatives and to investigate their antimicrobial and antivirulence activitiesagainst these isolates.Antibiotic susceptibility of the isolates was tested by combination of diffusion, dilution, andautomated methods, and additionally, identified colistin-resistant isolates were subjected to wholegenome sequencing (WGS) and were genetically characterized. Also, colistin resistancemechanisms were explored by using comparative genome analysis and Real-Time quantitativepolymerase chain reaction (RT-qPCR). Time-kill test was used for the measurement of bacterialsurvival in antiseptics, whereas the level of biofilm production under different cultivationconditions was quantified by in vitro static method using safranin stain. Hydroxychalconederivatives were synthesized by Claisen-Schmidt condensation, and their antimicrobial activities,alone and in combination with antibiotics, were investigated using broth-microdilution, Time-kill,and Checkerboard analyses. Antivirulence activities of selected chalcones were evaluated based onthe impact on biofilm production (monomicrobial and polymicrobial), biofilm cell viability,motility, virulence factors (OmpA, Bap, and AbaI) gene expression, fibronectin- and collagen-mediated adhesion, and quorum-sensing (QS) activity.A. baumannii clinical isolates expressed extensive drug-resistant or pan-drug resistantphenotypes, being nearly uniformly resistant to carbapenems. Almost 19% of isolates were resistantto colistin as well. The isolates proved to be able to contaminate the antiseptic solutions and toproduce large quantities of biofilms. Nutritional composition of growth media significantly affectedthe level of biofilm production. In contrast, wide range of different incubation temperatures and thepresence of antibiotics at subinhibitory concentrations had little effect, and the bacteria managed tomaintain high level of biofilm production. Moderate antimicrobial activity was displayed bysynthesized chalcones, among which methoxy-substituted derivatives achieved greatest growthinhibition in average. Also, synergistic activity of chalcones and meropenem was present in severalcases, for which efflux pump inhibition was proposed as the potential mechanism. The chalconessignificantly inhibited motility and biofilm production, whereas methoxy-substituted derivative (o-OCH3) also displayed significant antivirulence activity, by downregulating the ompA, bap, and abaIgene expression and by inhibiting fibronectin- and collagen-mediated adhesion. It can be concludedthat o-OCH3 has been identified as a potent antivirulence agent against A. baumannii
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