Despite the increasing prominence of research collaboration, a growing number of studies have confirmed that increasing team size can have limited performance benefits. However, the mechanism of this phenomenon has yet to be established. This study, therefore, quantified responsibility diffusion based on author contribution information and explored its mediating role in the relationship between collaboration size and citation impact (citation count in a four-year window). The results show the following: (1) An inverted U-shaped relationship exists between team size and citation count. (2) Responsibility diffusion plays a partial mediating role between team size and citation count. (3) As team size increases, the degree of responsibility diffusion increases. Lastly, (4) responsibility diffusion has an inverted U-shaped curvilinear relationship with citation count (e.g., a moderate degree of responsibility diffusion has the highest impact). These findings offer a new understanding of the mechanism by which collaboration size influences research performance. This study also has practical implications for solving research collaboration dilemmas based on a group-cognition perspective.

Four years after the EAT-Lancet landmark report, worldwide movements call for action to reorient food systems to healthy diets that respect planetary boundaries. Since dietary habits are inherently local and personal, any shift toward healthy and sustainable diets going against this identity will have an uphill road. Therefore, research should address the tension between the local and global nature of the biophysical (health, environment) and social dimensions (culture, economy). Advancing the food system transformation to healthy, sustainable diets transcends the personal control of engaging consumers. The challenge for science is to scale-up, to become more interdisciplinary, and to engage with policymakers and food system actors. This will provide the evidential basis to shift from the current narrative of price, convenience, and taste to one of health, sustainability, and equity. The breaches of planetary boundaries and the environmental and health costs of the food system can no longer be considered externalities. However, conflicting interests and traditions frustrate effective changes in the human-made food system. Public and private stakeholders must embrace social inclusiveness and include the role and accountability of all food system actors from the microlevel to the macrolevel. To achieve this food transformation, a new \"social contract,\" led by governments, is needed to redefine the economic and regulatory power balance between consumers and (inter)national food system actors.

A long-term (2013-2019) PM2.5 speciation dataset measured in Tianjin, the largest industrial city in northern China, was analyzed with dispersion normalized positive matrix factorization (DN-PMF). The trends of source apportioned PM2.5 were used to assess the effectiveness of source-specific control policies and measures in support of the two China\'s Clean Air Actions implemented nationwide in 2013-2017 and 2018-2020, respectively. Eight sources were resolved from the DN-PMF analysis: coal combustion (CC), biomass burning (BB), vehicular emissions, dust, steelmaking and galvanizing emissions, a mixed sulfate-rich factor and secondary nitrate. After adjustment for meteorological fluctuations, a substantial improvement in PM2.5 air quality was observed in Tianjin with decreases in PM2.5 at an annual rate of 6.6%/y. PM2.5 from CC decreased by 4.1%/y. The reductions in SO2 concentration, PM2.5 contributed by CC, and sulfate demonstrated the improved control of CC-related emissions and fuel quality. Policies aimed at eliminating winter-heating pollution have had substantial success as shown by reduced heating-related SO2, CC, and sulfate from 2013 to 2019. The two industrial source types showed sharp drops after the 2013 mandated controls went into effect to phaseout outdated iron/steel production and enforce tighter emission standards for these industries. BB reduced significantly by 2016 and remained low due to the no open field burning policy. Vehicular emissions and road/soil dust declined over the Action\'s first phase followed by positive upward trends, showing that further emission controls are needed. Nitrate concentrations remained constant although NOX emissions dropped significantly. The lack of a decrease in nitrate may result from increased ammonia emissions from enhanced vehicular NOX controls. The port and shipping emissions were evident implying their impacts on coastal air quality. These results affirm the effectiveness of the Clean Air Actions in reducing primary anthropogenic emissions. However, further emission reductions are needed to meet global health-based air quality standards.

Public voices have largely been absent from the discussions about open access publishing in medical research. Yet the public have a strong interest in ensuring open access of medical research findings because of their roles as funders, advocates, research participants, and patients. By limiting access to research outputs, the current publishing system makes it more difficult for research to be held accountable to the public. Paywalls undermine the work of public advocacy, which requires open access in order to lobby for policy changes and research funding. Research participants generously give their time and energy to research studies with the assumption that the results will be broadly disseminated. Finally, members of the public have a stake in open access publishing as a resource for health information and decision-making. This commentary explores these crucial roles of the public in order to develop a public rationale for open access medical research. We outline a critique of the current academic publishing ecosystem, re-focus the open access debate from a public perspective, and respond to some of the arguments against public open access. Although open access to medical research is not a panacea, removing paywalls and other barriers to public access is essential. The public are critical stakeholders of medical research data.

Content sharing platforms such as product review websites largely depend on reviewers\' voluntary contributions. In order to motivate reviewers to contribute more, many platforms established incentive mechanisms, either reputation-based or financial. Yet most of the existing research has focused on reputations that are everlasting, such as badges and virtual points, or financial rewards where no evaluation exists about the users\' contributed content, such as rebates. There is still a significant gap in our understanding of how incentives with reevaluation mechanism actually influence reviewers\' behaviors such as their contribution levels, the opinion they express, and how they express. In this paper, we fill this gap using data collected from Yelp Elite Squad where reviewers with good reviewing history are awarded into the elite group and most importantly reevaluated each year. We draw from the accountability theory and conduct a difference-in-differences analysis to empirically study the effect of incentives with reevaluation mechanism on reviewers\' behaviors in both short term and long term. The results show that in short term, reviewers significantly increase their contribution levels, become more conservative with lower percentage of extreme ratings, and also increase the readability of their reviews. In long term, they continue improving the quality of reviews though their numerical rating behaviors stabilize. Our research has significant implications for business models that rely on user contributions.

Smartphone apps present a great opportunity for the management of cardiovascular disease (CVD) as the adoption of apps becomes increasingly popular in China. Yet, little is known about the status of CVD-related Smartphone apps in the country. The aim of this study was to examine the current status of CVD-related smartphone apps available for download in China.
Using CVD-related keywords written either in Chinese or English, the top 6 most popular smartphone app online stores in China were searched in September 2015. The information accountability of the selected apps was assessed with the Silberg scale. The key topic areas identified from the European Guidelines on cardiovascular disease prevention served to determine information coverage of the top 5 downloaded apps.
The average Silberg score of 151 apps was 2.87 (out of 9) with most apps not revealing authors\' qualifications and information references. There was also a lack of sponsorship disclosure and information update. Moreover, none of the top 5 downloaded apps covered all key areas of CVD management as recommended by the European Guidelines on cardiovascular disease prevention. There was little evidence of health professionals\' involvement in the formation of the CVD-related apps.
This study identified areas for improvement concerning information accountability and the scope of coverage of CVD-related apps downloadable in China. The findings may guide the future advancement of CVD-related apps and benefit CVD management in China.