2,246 research outputs found

    The statistics of natural hand movements.

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    Humans constantly use their hands to interact with the environment and they engage spontaneously in a wide variety of manual activities during everyday life. In contrast, laboratory-based studies of hand function have used a limited range of predefined tasks. The natural movements made by the hand during everyday life have thus received little attention. Here, we developed a portable recording device that can be worn by subjects to track movements of their right hand as they go about their daily routine outside of a laboratory setting. We analyse the kinematic data using various statistical methods. Principal component analysis of the joint angular velocities showed that the first two components were highly conserved across subjects, explained 60% of the variance and were qualitatively similar to those reported in previous studies of reach-to-grasp movements. To examine the independence of the digits, we developed a measure based on the degree to which the movements of each digit could be linearly predicted from the movements of the other four digits. Our independence measure was highly correlated with results from previous studies of the hand, including the estimated size of the digit representations in primary motor cortex and other laboratory measures of digit individuation. Specifically, the thumb was found to be the most independent of the digits and the index finger was the most independent of the fingers. These results support and extend laboratory-based studies of the human hand

    Human mobility variations in response to restriction policies during the COVID-19 pandemic: An analysis from the Virus Watch community cohort in England, UK

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    Objective: Since the outbreak of COVID-19, public health and social measures to contain its transmission (e.g., social distancing and lockdowns) have dramatically changed people's lives in rural and urban areas globally. To facilitate future management of the pandemic, it is important to understand how different socio-demographic groups adhere to such demands. This study aims to evaluate the influences of restriction policies on human mobility variations associated with socio-demographic groups in England, UK. Methods: Using mobile phone global positioning system (GPS) trajectory data, we measured variations in human mobility across socio-demographic groups during different restriction periods from Oct 14, 2020 to Sep 15, 2021. The six restriction periods which varied in degree of mobility restriction policies, denoted as "Three-tier Restriction," "Second National Lockdown," "Four-tier Restriction," "Third National Lockdown," "Steps out of Lockdown," and "Post-restriction," respectively. Individual human mobility was measured with respect to the time period people stayed at home, visited places outside the home, and traveled long distances. We compared these indicators across the six restriction periods and across socio-demographic groups. Results: All human mobility indicators significantly differed across the six restriction periods, and the influences of restriction policies on individual mobility behaviors are correlated with socio-demographic groups. In particular, influences relating to mobility behaviors are stronger in younger and low-income groups in the second and third national lockdowns. Conclusions: This study enhances our understanding of the influences of COVID-19 pandemic restriction policies on human mobility behaviors within different social groups in England. The findings can be usefully extended to support policy-making by investigating human mobility and differences in policy effects across not only age and income groups, but also across geographical regions

    Active aging : the role of mechanical exposure on functional capacity of the active population in the automotive industry

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    A presente tese teve por objetivo compreender Ă s principais mudanças na capacidade funcional e na mobilidade dos trabalhadores seniores da indĂșstria automĂłvel, afim de promover uma adaptação efetiva das condiçÔes do trabalho, tendo como aliada a capacidade funcional dos trabalhadores em suas diferentes faixas etĂĄrias, com destaque aqueles que pertencem ao grupo etĂĄrio acima dos 40 anos. Os capĂ­tulo 2 e 3, respectivamente, tiveram como enfoque a interação entre as condiçÔes de trabalho e a capacidade funcional dos trabalhadores da indĂșstria automĂłvel e a definição de perfis de capacidade funcional. Os resultados encontrados no capĂ­tulo 2 demonstraram que as exigĂȘncias de força, altura e peso e a antiguidade na empresa, foram fatores preditivos para o declĂ­nio da capacidade funcional nos testes de Lifting Low, Lifting High e Handgrip. O resultado de destaque no capĂ­tulo 3 estĂĄ no grupo etĂĄrio dos 20-29 anos, com os menores valores referentes ao teste de capacidade funcional Handgrip e Overhead Working, em relação aos demais grupos etĂĄrios. Tanto no capĂ­tulo 2 quanto no 3, a medida mais robusta dos testes de capacidade funcional, foi a medida Handgrip. No capĂ­tulo 4, foram definidos os valores normativos de força de preensĂŁo (Handgrip). Os resultados mais expressivos, deste capĂ­tulo, estĂŁo relacionados ao grupo das mulheres dos 30-34 anos, com um declĂ­nio significativo de 4 kg a menos de força de preensĂŁo, em comparação aos demais grupos etĂĄrios. E no grupo dos homens o declĂ­nio ocorreu na faixa etĂĄrio dos 40-57 anos, como esperado. ConcluĂ­sse nesta presente tese que os trabalhadores seniores nĂŁo demonstram declĂ­nios significativos da capacidade funcional.The present thesis aimed to understand the main changes in the functional capacity and mobility of senior workers in the automotive industry. To promote an active adaptation of work requirements, having as an ally the functional capacity of workers in their different age groups, with emphasis those belonging to the age group above 40 years. Chapters 2 and 3, respectively, focused on the interaction between working conditions and the functional capacity of workers in the automotive industry and the definition of functional capacity profiles. The results found in chapter 2, demonstrated that the strength (related to work requirements), height and weight and seniority in the company, were predictive factors for the decline in functional capacity in the Lifting Low, Lifting High, and Handgrip tests. The outstanding result in chapter 3 is in the 20-29 age group, with the lowest values referring to the Handgrip and Overhead Working Functional Capacity Test, concerning the other age groups. In both chapters 2 and 3, the most robust measure of functional capacity tests was the Handgrip measure. So, in chapter 4, defined normative values of grip strength (Handgrip). The most significant results in this chapter are related to the group of women aged 30-34 years, with a substantial decline of 4 kg less grip strength, compared to the other age groups. And in the male group, the decline occurred in the 40-57 age group, as expected. It is concluded in this thesis that the senior workers do not demonstrate significant declines in functional capacity

    Critical behavior in interdependent spatial spreading processes with distinct characteristic time scales

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    AbstractThe spread of an infectious disease is well approximated by metapopulation networks connected by human mobility flow and upon which an epidemiological model is defined. In order to account for travel restrictions or cancellation we introduce a model with a parameter that explicitly indicates the ratio between the time scales of the intervening processes. We study the critical properties of the epidemic process and its dependence on such a parameter. We find that the critical threshold separating the absorbing state from the active state depends on the scale parameter and exhibits a critical behavior itself: a metacritical point – a critical value in the curve of critical points – reflected in the behavior of the attack rate measured for a wide range of empirical metapopulation systems. Our results have potential policy implications, since they establish a non-trivial critical behavior between temporal scales of reaction (epidemic spread) and diffusion (human mobility) processes

    Introduction: Popular Economies in South Africa

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    African economies have long been a matter of concern to anthropologists, not least in the pages of Africa. These economies are situated, somewhat contradictorily, between global settings of financialized capitalism on the one hand and impoverished local arenas where cash-based economic transfers predominate on the other. The more such economies appear to be tied to wider global arenas and operations that place them beyond the reach of ordinary people, the more necessary it is to explore the logics and decisions that tie them inexorably to specific everyday settings

    Individual variation in susceptibility or exposure to SARS-CoV-2 lowers the herd immunity threshold

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    Funding Information: We thank Jorge Carneiro, Ben Cooper, JosĂ© Ferreira Machado, Kate Langwig, Robert MacKay, Paul McKeigue, Antonio MontalbĂĄn, Joe Schoneman, Laurette Tuckerman and Simon Wood for valuable discussions throughout this study. At the University of Strathclyde, Matthew Burns, Zhichun Jiang, Naithan McNeil, Lauren Schofield and Aidan West conducted their final year BSc projects on Communicating Mathematics and Statistics, supervised by M.G.M.G., on topics related to this study while this paper was being written. This has contributed clarity to our presentation. The models presented here were first submitted to medRxiv on 27 April 2020 and posted soon after. Applications to the COVID-19 pandemic and subsequent updates followed. We are grateful to the preprint server for making our work available to interested readers in real time. M.U.F. received funding from Conselho Nacional de Desenvolvimento CientĂ­fico e TecnolĂłgico, Brazil. Funding Information: We thank Jorge Carneiro, Ben Cooper, Jos? Ferreira Machado, Kate Langwig, Robert MacKay, Paul McKeigue, Antonio Montalb?n, Joe Schoneman, Laurette Tuckerman and Simon Wood for valuable discussions throughout this study. At the University of Strathclyde, Matthew Burns, Zhichun Jiang, Naithan McNeil, Lauren Schofield and Aidan West conducted their final year BSc projects on Communicating Mathematics and Statistics, supervised by M.G.M.G. on topics related to this study while this paper was being written. This has contributed clarity to our presentation. The models presented here were first submitted to medRxiv on 27 April 2020 and posted soon after. Applications to the COVID-19 pandemic and subsequent updates followed. We are grateful to the preprint server for making our work available to interested readers in real time. M.U.F. received funding from Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico, Brazil. Publisher Copyright: © 2022 Elsevier LtdIndividual variation in susceptibility and exposure is subject to selection by natural infection, accelerating the acquisition of immunity, and reducing herd immunity thresholds and epidemic final sizes. This is a manifestation of a wider population phenomenon known as “frailty variation”. Despite theoretical understanding, public health policies continue to be guided by mathematical models that leave out considerable variation and as a result inflate projected disease burdens and overestimate the impact of interventions. Here we focus on trajectories of the coronavirus disease (COVID-19) pandemic in England and Scotland until November 2021. We fit models to series of daily deaths and infer relevant epidemiological parameters, including coefficients of variation and effects of non-pharmaceutical interventions which we find in agreement with independent empirical estimates based on contact surveys. Our estimates are robust to whether the analysed data series encompass one or two pandemic waves and enable projections compatible with subsequent dynamics. We conclude that vaccination programmes may have contributed modestly to the acquisition of herd immunity in populations with high levels of pre-existing naturally acquired immunity, while being crucial to protect vulnerable individuals from severe outcomes as the virus becomes endemic.publishersversionpublishe

    Object Handovers: a Review for Robotics

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    This article surveys the literature on human-robot object handovers. A handover is a collaborative joint action where an agent, the giver, gives an object to another agent, the receiver. The physical exchange starts when the receiver first contacts the object held by the giver and ends when the giver fully releases the object to the receiver. However, important cognitive and physical processes begin before the physical exchange, including initiating implicit agreement with respect to the location and timing of the exchange. From this perspective, we structure our review into the two main phases delimited by the aforementioned events: 1) a pre-handover phase, and 2) the physical exchange. We focus our analysis on the two actors (giver and receiver) and report the state of the art of robotic givers (robot-to-human handovers) and the robotic receivers (human-to-robot handovers). We report a comprehensive list of qualitative and quantitative metrics commonly used to assess the interaction. While focusing our review on the cognitive level (e.g., prediction, perception, motion planning, learning) and the physical level (e.g., motion, grasping, grip release) of the handover, we briefly discuss also the concepts of safety, social context, and ergonomics. We compare the behaviours displayed during human-to-human handovers to the state of the art of robotic assistants, and identify the major areas of improvement for robotic assistants to reach performance comparable to human interactions. Finally, we propose a minimal set of metrics that should be used in order to enable a fair comparison among the approaches.Comment: Review paper, 19 page

    Complex Urban Systems: Challenges and Integrated Solutions for the Sustainability and Resilience of Cities

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    For decades, from design theory to urban planning and management, from social sciences to urban environmental science, cities have been probed and analyzed from the partial perspective of single disciplines. The digital era, with its unprecedented data availability, is allowing for testing old theories and developing new ones, ultimately challenging relatively partial models. Our community has been in the last years providing more and more compelling evidence that cities are complex systems with emergent phenomena characterized by the collective behavior of their citizens who are themselves complex systems. However, more recently, it has also been shown that such multiscale complexity alone is not enough to describe some salient features of urban systems. Multilayer network modeling, accounting for both multiplexity of relationships and interdependencies among the city's subsystems, is indeed providing a novel integrated framework to study urban backbones, their resilience to unexpected perturbations due to internal or external factors, and their human flows. In this paper, we first offer an overview of the transdisciplinary efforts made to cope with the three dimensions of complexity of the city: the complexity of the urban environment, the complexity of human cognition about the city, and the complexity of city planning. In particular, we discuss how the most recent findings, for example, relating the health and wellbeing of communities to urban structure and function, from traffic congestion to distinct types of pollution, can be better understood considering a city as a multiscale and multilayer complex system. The new challenges posed by the postpandemic scenario give to this perspective an unprecedented relevance, with the necessity to address issues of reconstruction of the social fabric, recovery from prolonged psychological, social and economic stress with the ensuing mental health and wellbeing issues, and repurposing of urban organization as a consequence of new emerging practices such as massive remote working. By rethinking cities as large-scale active matter systems far from equilibrium which consume energy, process information, and adapt to the environment, we argue that enhancing social engagement, for example, involving citizens in codesigning the city and its changes in this critical postpandemic phase, can trigger widespread adoption of good practices leading to emergent effects with collective benefits which can be directly measured

    Individual variation in susceptibility or exposure to SARS-CoV-2 lowers the herd immunity threshold

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    Individual variation in susceptibility and exposure is subject to selection by natural infection, accelerating the acquisition of immunity, and reducing herd immunity thresholds and epidemic final sizes. This is a manifestation of a wider population phenomenon known as “frailty variation”. Despite theoretical understanding, public health policies continue to be guided by mathematical models that leave out considerable variation and as a result inflate projected disease burdens and overestimate the impact of interventions. Here we focus on trajectories of the coronavirus disease (COVID-19) pandemic in England and Scotland until November 2021. We fit models to series of daily deaths and infer relevant epidemiological parameters, including coefficients of variation and effects of non-pharmaceutical interventions which we find in agreement with independent empirical estimates based on contact surveys. Our estimates are robust to whether the analysed data series encompass one or two pandemic waves and enable projections compatible with subsequent dynamics. We conclude that vaccination programmes may have contributed modestly to the acquisition of herd immunity in populations with high levels of pre-existing naturally acquired immunity, while being crucial to protect vulnerable individuals from severe outcomes as the virus becomes endemic
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