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- Vuorinen, V., et al.
(author)
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Modelling aerosol transport and virus exposure with numerical simulations in relation to SARS-CoV-2 transmission by inhalation indoors
- 2020
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In: Safety Science. - : Elsevier BV. - 0925-7535. ; 130
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Journal article (peer-reviewed)abstract
- We provide research findings on the physics of aerosol and droplet dispersion relevant to the hypothesized aerosol transmission of SARS-CoV-2 during the current pandemic. We utilize physics-based modeling at different levels of complexity, along with previous literature on coronaviruses, to investigate the possibility of airborne transmission. The previous literature, our 0D-3D simulations by various physics-based models, and theoretical calculations, indicate that the typical size range of speech and cough originated droplets (d⩽20μm) allows lingering in the air for O(1h) so that they could be inhaled. Consistent with the previous literature, numerical evidence on the rapid drying process of even large droplets, up to sizes O(100μm), into droplet nuclei/aerosols is provided. Based on the literature and the public media sources, we provide evidence that the individuals, who have been tested positive on COVID-19, could have been exposed to aerosols/droplet nuclei by inhaling them in significant numbers e.g. O(100). By 3D scale-resolving computational fluid dynamics (CFD) simulations, we give various examples on the transport and dilution of aerosols (d⩽20μm) over distances O(10m) in generic environments. We study susceptible and infected individuals in generic public places by Monte-Carlo modelling. The developed model takes into account the locally varying aerosol concentration levels which the susceptible accumulate via inhalation. The introduced concept, ’exposure time’ to virus containing aerosols is proposed to complement the traditional ’safety distance’ thinking. We show that the exposure time to inhale O(100) aerosols could range from O(1s) to O(1min) or even to O(1h) depending on the situation. The Monte-Carlo simulations, along with the theory, provide clear quantitative insight to the exposure time in different public indoor environments.
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| 2. |
- Cagigi, Alberto, et al.
(author)
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Airway antibodies emerge according to COVID-19 severity and wane rapidly but reappear after SARS-CoV-2 vaccination
- 2021
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In: JCI Insight. - : American Society for Clinical Investigation. - 2379-3708. ; 6:22
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Journal article (peer-reviewed)abstract
- Understanding the presence and durability of antibodies against SARS-CoV-2 in the airways is required to provide insights into the ability of individuals to neutralize the virus locally and prevent viral spread. Here, we longitudinally assessed both systemic and airway immune responses upon SARS-CoV-2 infection in a clinically well-characterized cohort of 147 infected individuals representing the full spectrum of COVID-19 severity, from asymptomatic infection to fatal disease. In addition, we evaluated how SARS-CoV-2 vaccination influenced the antibody responses in a subset of these individuals during convalescence as compared with naive individuals. Not only systemic but also airway antibody responses correlated with the degree of COVID-19 disease severity. However, although systemic IgG levels were durable for up to 8 months, airway IgG and IgA declined significantly within 3 months. After vaccination, there was an increase in both systemic and airway antibodies, in particular IgG, often exceeding the levels found during acute disease. In contrast, naive individuals showed low airway antibodies after vaccination. In the former COVID-19 patients, airway antibody levels were significantly elevated after the boost vaccination, highlighting the importance of prime and boost vaccinations for previously infected individuals to obtain optimal mucosal protection.
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| 4. |
- Mwanika, K., et al.
(author)
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Colonial legacies and contemporary commercial farming outcomes: sugarcane in Eastern Uganda
- 2021
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In: Third World Quarterly. - : Informa UK Limited. - 0143-6597 .- 1360-2241. ; 42:5, s. 1014-1032
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Journal article (peer-reviewed)abstract
- This article explores the impact of nineteenth-century colonial activities of cash crop farming which altered existing forms of land use from subsistence to capitalist commercial farming. Such modifications had long-term implications for postcolonial development paths by producing and reproducing structures that skew the benefits of commercial farming towards the capitalist agenda at the expense of the welfare of the local population. The article builds on the debates over colonial legacies of agrarian transformation using commercial sugarcane farming in eastern Uganda. Using youth surveys, qualitative tools and document reviews, the authors argue that the detrimental effects of sugarcane farming are a recurrence of capitalism rooted in colonial imperialist policies in Uganda. Through its processes of accumulation by dispossession, colonial-era capitalist systems continue to operate through land seizure for sugarcane farming at the expense of food crops, precipitating food insecurity. It has also pushed the indigenous population into a very vulnerable situation, offering poorly remunerated and extremely exploitative jobs in sugarcane farming. The authors argue that the broader historical context of colonialism is relevant in explaining the contemporary dynamics associated with activities such as commercial farming in postcolonial societies.
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