Intelligent e-wastes processing for effective end-of-life management

Intelligent e-wastes processing for effective end-of-life management</p

Three Essays on Behaviors in Crowdsourcing Communities

Over the last decade, the interest in studying crowdsourcing platforms has dramatically increased among researchers in the information systems (IS) area. My dissertation includes three essays on crowdsourcing. The first essay provides an extensive literature review on crowdsourcing and shows several gaps in the literature. The second essay highlights the gaps in the literature on innovation contest platforms and draws on the organizational learning literature to fill the gaps. In this research, I draw on the organizational learning literature to study the undelying dynamics of specialization and variation in innovation contest platforms. Using data of nearly 35000 users\u27 participation history in competitions hosted on Kaggle, I find that both specialization and variation play key roles in individuals\u27 performance in innovation contest platforms and reinforce each other. My findings reveal that their influence on performance is contingent on contest characteristics. The third essay investigates idea quality and the number of submitted ideas on idea crowdsourcing platforms for new product development (NPD). My review of the literature in this area reveals that the relationships between interacting with peers’ ideas through idea evaluation performance and cognitive effort on feedbacks to peers\u27 ideas and the quality of past ideas on idea quality and the number of submitted ideas that have not been studied in the literature. To fill these gaps, I draw on the literature on idea crowdsourcing, creativity, attention, and goal attainment to develop hypotheses regarding the role of these factors on idea quality and the number of submitted ideas in idea crowdsourcing platforms for NPD. Based on the data collected from Lego Ideas, I show that users with better idea evaluation performance generate higher quality ideas and submit fewer ideas. I also find that cognitive effort on feedback to peers’ ideas has a significant positive impact on the number of submitted ideas. Furthermore, the results indicate an inverted U-shape relationship between the average quality of past ideas and idea quality and the number of submitted ideas. Besides filling several gaps in the literature, my research findings offer several implications for crowdsourcing platform sponsors to design better platforms

Assessment of the costs of fatal occupational accidents in Tehran

Background: Occupational accidents are major health problems in both developed and developing countries. The most important aspect is death leading to loss of years of life and work. The objective of this study is evaluation of human costs of fatal occupational accidents in the insured employees by Human Capital method in Tehran. Materials and Methods: Data for this study were collected through specific checklists filled in by referring to the branches of the Social Security Organization. Human costs were calculated by determination of the lost years of life, years of active economic function as well as annual income of the deceased people. Results: In the three years of the study 7552 years of life and 3656 years of work have been lost because of the occupational accidents. Findings also showed that human cost for each occupational accident was 3.36 billion Rials. Human costs of fatal occupational accidents for each year of study was found to be equal to 0.03 percent of Iran's GDP. Conclusion: Very high expenses of occupational accidents mandates more attention to the occupational health and safety services

Idea Quality and the Number of Submitted Ideas: An Empirical Study on Lego Ideas

This research explores idea quality and the number of submitted ideas on idea crowdsourcing platforms for new product development (NPD) from two perspectives: individuals’ past performance (average quality of past ideas) and interaction with peers’ ideas (attention intensity and attention focus quality). By drawing on the creativity, attention, and crowdsourcing literatures, we argue that attention to peers’ ideas could stimulate new ideas and discourage users from submitting lower quality ideas. We also suggest that there is an inverted U-shape relationship between the average quality of past ideas and idea quality and the number of submitted ideas in idea crowdsourcing platforms for NPD that suggests users with the ability to generate high-quality ideas reduce their effort after the quality of their ideas passes a point (goal attainment). Using the data collected from Lego Ideas, we find support for most of our hypotheses. Our findings have several theoretical and practical implications

Comparative Study of the Effect of Flavonoids and the Whey Extract on Enamel Microhardness: An In Vitro Study

Background: Preventing caries or stopping primary caries lesions is one of the most important goals of oral health care. The aim of this study was to compare the effect of flavonoids and the whey extract on tooth enamel by measuring the microhardness of enamel following its demineralization. Methods: In general, 42 samples of healthy enamel were prepared in this experimental-laboratory study. After measuring the initial microhardness using Vickers hardness tester )Buehler, Lake Bluff, IL, USA(, the samples were immersed in the demineralization solution for 4 days and re-tested for microhardness. Then, the samples were randomly divided into three groups of 14 and treated, including the grape seed extract w/v8%, the whey extract, and the artificial saliva. The samples were in contact with the treatment material for 8 days in an incubator at 37°C and then their microhardness was evaluated again. Results: The analysis of covariance showed that there was a significant difference in the amount of microhardness changes between the study groups (P &lt; 0.001) so that microhardness changes were the highest in the grape seed extract group while they decreased in the control group. However, the post hoc test showed no statistically significant difference between the whey extract and grape seed extract groups (P = 1.000). Finally, the control group had a statistically significant difference from the whey extract and grape seed extract groups. Conclusions: Both grape seed extract and whey extract increased remineralization and the microhardness of tooth enamel compared to the control group. Thus, these two substances can be considered as natural and effective substances in the non-invasive treatment of carious lesions.</jats:p