Bringing trust and transparency to the opaque world of waste management with blockchain: A Polkadot parathread application

The majority of countries are currently struggling with unsustainable levels of waste production and low levels of recycling, particularly relating to household waste, and this area is in urgent need of new solutions. In general, the waste management sector has struggled with low consumer trust, fraud, manipulation, significant manual processes, and low levels of information and control. Recent events relating to the COVID-19 pandemic have highlighted, in particular, the role of trust in effective public policy making and consumer behavioural change. Here we propose a hybrid blockchain solution called a Polkadot parachain. Polkadot is a blockchain technology that connects a network of blockchains, each called a parachain, that can be customised to the business needs of a given application. This solution provides the cost benefits, scalability, and control of a permissioned or private blockchain while providing the security, verifiability, and trust of a public blockchain. The solution is developed with a design science approach and combines three typically separate blockchain use cases: supply chain tracking, incentivisation through a payment system, and gamification to achieve a complete solution for waste management. We provide a detailed discussion on the design of this blockchain solution with the use of blockchain functionality assessed against the criteria and development approaches found in the literature. Finally, we demonstrate how such a blockchain can be implemented with the Substrate blockchain development framework.

Walkability Indicators in the Aftermath of the COVID-19 Pandemic: A Systematic Review

Walkability indicators are a pivotal method to evaluate the role of the built environment in people's decisions regarding active mobility, contributing to help promote more sustainable and equitable regions. Currently, there is a lack of literature describing the trends and findings from recent studies, and how research on this topic has responded to COVID-19. In this work, we apply the PRISMA methodology to perform a systematic literature review of studies that employed walkability indicators to uncover associations between walkability and different topics, such as physical activity, health and mobility, in the aftermath of the pandemic. Results show that the growth rate of studies in this period almost doubled compared to the three years prior to the outbreak. We explore the main subjects addressed in recent literature and found that most studies resorted to well-known indicators, predominantly to Walk Score®, while fewer works developed and applied new indicators. General findings point to a positive association between walkability and physical activity, overall health and active mobility. Moreover, in recent works, walkability's relationship with environmental metrics is not clear and there is a lack of studies linking walkability indicators to COVID-19. More than two years after the worldwide outbreak of the COVID-19 virus, our work provides an effective resource for researchers to understand recent trends in studies employing walkability indicators.

Beyond comorbidities, sex and age have no effect on COVID-19 health care demand.

This paper explores the associations between sex, age and hospital health care pressure in the context of the COVID-19 pandemic in Portuguese mainland municipalities. To represent the impact of sex and age, we calculated COVID-19 standardised incidence ratios (SIR) in Portuguese mainland municipalities over fourteen months daily, especially focusing on the Porto metropolitan area. A daily novel indicator was devised for hospital health care pressure, consisting of an approximation to the ratio of hospitalisations per available hospital medical doctor (HPI). In addition, 14-day incidence rates were also calculated daily (DIR14), both as an approach and an alternative to the current national pandemic surveillance indicator (which is not calculated with such regularity). Daily maps were first visualised to evaluate spatial patterns. Pearson's correlation coefficients were then calculated between each proposed surveillance indicator (SIR and DIR14) and the HPI. Our results suggest that hospital pressure is not strongly associated with SIR (r = 0.34, p value = 0.08). However, DIR14 bears a stronger correlation with hospital pressure (r = 0.84, p value < 0.001). By establishing the importance of tackling sex and age through the inclusion of these factors explicitly in an epidemiological monitoring indicator, and assessing its relationship with a hospital pressure indicator, our findings have public policy implications that could improve COVID-19 incidence surveillance in Portugal and elsewhere, contributing to advancing the management of potential pandemics in the near future, with a particular focus on local and regional territorial scales.

Impact of COVID-19 lockdown measures on waste production behavior in Lisbon.

The recent restrictions on mobility and economic activities imposed by governments due to the COVID-19 pandemic have significantly affected waste production and recycling patterns in cities worldwide. This effect differed both between cities and within cities as the measures of confinement adopted by governments had diverse impacts in different areas of cities, depending on their characteristics (e.g., touristic, or residential). In the present work, mixed waste collection areas were created, based on waste collection points, that define spatial units in which contextual data such as tourism and residential characteristics were aggregated. The difference in mixed waste collected compared with previous years was analyzed along with the impacts on recycling due to the modification in operations regarding waste collection during the lockdown. The results showed that despite the suspension of the door-to-door recycling system during the lockdown, this did not translate into an increase in the production of mixed waste, and the recycling levels of previous years have not been reached after the lockdown, indicating a possible change in recycling habits in Lisbon. The touristic and non-residential mixed waste circuits presented significantly reduced mixed waste production compared to the non-pandemic context. Also, tourist, mobility, and economic activity were measured to understand which factors contributed to waste production changes during the COVID-19 pandemic. While little evidence of a relationship with these exogenous variables was found at the citywide level, evidence was found at the waste collection circuit level.