A Theory of Reward Stability, Justice Evaluations and Group Cooperation

The objective of this dissertation is to introduce a theory of the stability of rewards, justice evaluations and group cooperation with the results from three empirical tests of the theory. According to justice theory, rewards from exchange relations produce justice evaluations among individuals, leading to emotional and behavioral reactions. Specifically, unjust rewards cause lower levels of justice evaluations, positive emotions, and cooperative behaviors. Prospect theory and research on negativity bias posit the asymmetry between negative and positive events: negative events have a stronger effect than the same size of positive events on individuals’ perception. Combining the previous arguments, the theory introduced in this dissertation maintains that in repeated rewards events, the instability of rewards itself has a negative effect. That is, unstable rewards lower justice evaluations, positive emotions, and willingness to cooperate. The theory is tested with three mixed quantitative methodologies. Results from analyses of nationally representative sample survey data show that the stability of rules in workplaces has a positive effect on justice evaluations, willingness to work hard and willingness to stay in current workplaces among employees. Next, a controlled laboratory experiment tests the theory more rigorously. The results reveal the positive effect of the stability of rewards on justice evaluations, positive emotions, and cooperative behaviors. The second experiment replicates the results from the first experiment and confirms the effectiveness of the theory. The experiment also tests the effect of the presenting order of instability of rewards and shows that reward instability occurring earlier has a stronger effect than that which occurs later. The implications of findings on sociological theory and other various areas are discussed

Effect of the Phosphorus Gettering on Si Heterojunction Solar Cells

To improve the efficiency of crystalline silicon solar cells, should be collected the excess carrier as much as possible. Therefore, minimizing the recombination both at the bulk and surface regions is important. Impurities make recombination sites and they are the major reason for recombination. Phosphorus (P) gettering was introduced to reduce metal impurities in the bulk region of Si wafers and then to improve the efficiency of Si heterojunction solar cells fabricated on the wafers. Resistivity of wafers was measured by a four-point probe method. Fill factor of solar cells was measured by a solar simulator. Saturation current and ideality factor were calculated from a dark current density-voltage graph. External quantum efficiency was analyzed to assess the effect of P gettering on the performance of solar cells. Minority bulk lifetime measured by microwave photoconductance decay increases from 368.3 to 660.8 mu s. Open-circuit voltage and short-circuit current density increase from 577 to 598 mV and 27.8 to 29.8mA/cm(2), respectively. The efficiency of solar cells increases from 11.9 to 13.4%. P gettering will be feasible to improve the efficiency of Si heterojunction solar cells fabricated on P-doped Si wafers.open1

Discovery of chemerin as the new chemoattractant of human mesenchymal stem cells

Background The homing capacity of human mesenchymal stem cells (hMSCs) to the injured sites enables systemic administration of hMSCs in clinical practice. In reality, only a small proportion of MSCs are detected in the target tissue, which is a major bottleneck for MSC-based therapies. We still dont know the mechanism how MSCs are chemo-attracted to certain target organ and engrafted through trans-endothelial migration. In this study, we aimed to determine the mechanism how the circulating hMSCs home to the injured liver. Methods and results When we compare the cytokine array between normal and injured mouse liver at 1-day thioacetamide (TAA)-treatment, we found that chemerin, CXCL2, and CXCL10 were higher in the injured liver than normal one. Among three, only chemerin was the chemoattractant of hMSCs in 2D- and 3D-migration assay. Analysis of the signal transduction pathways in hMSCs showed that chemerin activated the phosphorylation of JNK1/2, ERK1/2 and p38, and finally upregulated CD44, ITGA4, and MMP-2 that are involved in the transendothelial migration and extravasation of MSCs. Upstream transcription regulators of CD44, ITGA4, and MMP-2 after chemerin treatment were MZF1, GATA3, STAT3, and STAT5A. To develop chemerin as a chemoattractant tool, we cloned gene encoding the active chemerin under the CMV promoter (CMV-aChemerin). We analyzed the migration of hMSCs in the 3D model for space of the Disse, which mimics transmigration of hMSCs in the liver. CMV-aChemerin-transfected hepatocytes were more effective to attract hMSC than control hepatocytes, leading to the enhanced transendothelial migration and homing of hMSCs to liver. The homing efficiency of the intravascularly-delivered hMSCs to liver was evaluated after systemic introduction of the CMV-aChemerin plasmid packed in liposome-vitamin A conjugates which target liver. CMV-aChemerin plasmid targeting liver significantly enhanced homing efficiency of hMSCs to liver compared with control plasmid vector. Conclusions Chemerin is the newly found chemoattractant of hMSCs and may be a useful tool to manipulate the homing of the intravascularly-administered hMSC to the specific target organ.This work was supported by the Korea Health Technology R&D Project Strategic Center of Cell and Bio Therapy [Grant number HI17C2085] and Korea Research-Driven Hospital [Grant number HI14C1277] through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare (MHW), Republic of Korea. The funders had no role in the study design, data collection and analysis, deci‑sion to publish, or preparation of the manuscript

Traumatic Stress of Frontline Workers in Culling Livestock Animals in South Korea

The last decade brought several devastating outbreaks of foot and mouth disease and avian influenza in South Korea, which had been handled through preventive culling, despite the controversy surrounding its efficiency and ethical considerations. Notably, the lack of regulations on culling processes has exposed the workers to extremely harsh working conditions. This study investigates the effect of culling jobs on the mental health of the frontline workers, based on 200 samples collected through a web-based survey conducted on participants with experience of culling tasks. Culling was found to have a powerful negative effect on the workers’ mental health, including high depression rates. Of those surveyed, 83.7% answered that the working conditions were intense, and 74.5% showed scores above the cutoff point for post-traumatic stress disorder (PTSD). A regression analysis revealed that individual’s attitudes toward animals mediated the effect of culling experience on PTSD symptoms. However, mental health care for the workers has been insufficient: 70.2% of the respondents were willing to get mental treatment to deal with the distress they underwent from culling. We conclude that engagement in culling has a detrimental effect on the workers’ mental health, and that they should be provided with systematic mental health care

Spatial Characteristics of Wildlife-Vehicle Collisions of Water Deer in Korea Expressway

In recent decades, rapid industrial growth has accelerated the construction of new roads, which has led to the destruction and isolation of wildlife habitats. Newly constructed roads affect wildlife in many ways. In particular, fatal wildlife-vehicle collisions (WVCs) have a direct impact on wildlife. A substantial number of WVCs occur every year on expressways, where vehicle speeds and vehicle traffic are significant. However, our understanding of the relative importance of the factors associated with areas in which large numbers of WVCs occur on the expressway remains poor. Therefore, herein, we analyze the spatial characteristics of WVCs. The effect of spatial distribution on the occurrence of WVCs was analyzed using the types of land cover in the areas where water deer appear (Cheongju, Boeun, and Sangju) and the areas in which WVCs occur along the Cheongju–Sangju Expressway (CSE). We identified the WVC hotspots by using CSE patrol data recorded between January 2008 and December 2019, and we analyzed the corresponding distribution patterns and land cover characteristics. Along the CSE, a total of 1082 WVCs occurred, out of which collisions involving water deer (Hydropotes inermis argyropus) accounted for 91%. Water deer appear frequently in Forested Areas and Agricultural Land, but the WVC distribution in the Hotspots followed a highly clustered pattern, with a higher proportion of WVCs occurring in Used Areas (areas including buildings such as residential facilities, commercial and industrial facilities, and transportation facilities). Used Areas have a smaller cut slope compared to Forested Areas, and Used Areas are open terrains. Therefore, the occurrence of WVCs will be high given that wildlife can easily access the expressway. Based on these results, we can infer that the landscapes near the expressway influence the occurrence of WVCs. To establish an effective policy for reducing WVCs on a road, the WVC characteristics and spatial distribution of the road should be considered together. Further research on the wildlife ecology and land-use status of WVC hotspots is required to mitigate WVCs on expressways and protect human and animal life. Therefore, if the characteristics of WVC hotspots are analyzed considering the characteristics of various ecosystems, an appropriate WVC reduction plan can be established

The Effects of Stability and Presentation Order of Rewards on Justice Evaluations

<div><p>Justice research has evolved by elucidating the factors that affect justice evaluations, as well as their consequences. Unfortunately, few researchers have paid attention to the pattern of rewards over time as a predictor of justice evaluations. There are two main objectives of this research. First, it aims to test the effect of reward stability on justice evaluations. Based on justice theory and prospect theory, we assume that an under-reward at one time cannot be fully offset by an equivalent over-reward at another time. Therefore, in unstable reward systems the asymmetry of the effect of unjust rewards with opposite directions will produce a lower level of justice evaluations over time. The second objective of this research is to show the moderating effect of the presentation order (primacy vs. recency) of unstable rewards on justice evaluations. The results from a controlled experiment with five conditions, which presents the instability of rewards in different orders, confirm both the negative effect of unstable rewards and the stronger effect of primacy on justice evaluations.</p></div

Spatial Characteristics of Wildlife-Vehicle Collisions of Water Deer in Korea Expressway

In recent decades, rapid industrial growth has accelerated the construction of new roads, which has led to the destruction and isolation of wildlife habitats. Newly constructed roads affect wildlife in many ways. In particular, fatal wildlife-vehicle collisions (WVCs) have a direct impact on wildlife. A substantial number of WVCs occur every year on expressways, where vehicle speeds and vehicle traffic are significant. However, our understanding of the relative importance of the factors associated with areas in which large numbers of WVCs occur on the expressway remains poor. Therefore, herein, we analyze the spatial characteristics of WVCs. The effect of spatial distribution on the occurrence of WVCs was analyzed using the types of land cover in the areas where water deer appear (Cheongju, Boeun, and Sangju) and the areas in which WVCs occur along the Cheongju–Sangju Expressway (CSE). We identified the WVC hotspots by using CSE patrol data recorded between January 2008 and December 2019, and we analyzed the corresponding distribution patterns and land cover characteristics. Along the CSE, a total of 1082 WVCs occurred, out of which collisions involving water deer (Hydropotes inermis argyropus) accounted for 91%. Water deer appear frequently in Forested Areas and Agricultural Land, but the WVC distribution in the Hotspots followed a highly clustered pattern, with a higher proportion of WVCs occurring in Used Areas (areas including buildings such as residential facilities, commercial and industrial facilities, and transportation facilities). Used Areas have a smaller cut slope compared to Forested Areas, and Used Areas are open terrains. Therefore, the occurrence of WVCs will be high given that wildlife can easily access the expressway. Based on these results, we can infer that the landscapes near the expressway influence the occurrence of WVCs. To establish an effective policy for reducing WVCs on a road, the WVC characteristics and spatial distribution of the road should be considered together. Further research on the wildlife ecology and land-use status of WVC hotspots is required to mitigate WVCs on expressways and protect human and animal life. Therefore, if the characteristics of WVC hotspots are analyzed considering the characteristics of various ecosystems, an appropriate WVC reduction plan can be established

Estimated Justice Evaluations across the Conditions.

<p>Estimated Justice Evaluations across the Conditions.</p