Effects of Gamification Elements on Crowdsourcing Participation: The Mediating Role of Justice Perceptions

Justice perceptions have been regarded as an important influencing factor for solvers’ (i.e., users who solve tasks on the crowdsourcing platforms) continued participation in crowdsourcing. However, researchers and practitioners still lack of sufficient understanding on the design of crowdsourcing platform that can effectively foster solvers’ justice perceptions. By synthesizing theory of organizational justice and the literature on gamification, we examine the effects of solvers’ gamification element perceptions on their crowdsourcing participation through justice perceptions. Specifically, we propose a research model to explain the effects of three gamification element perceptions (i.e., point, feedback, social network) on solvers’ distributive, interactional, and informational justice perceptions which, in turn, foster their crowdsourcing participation. By collecting survey data from 295 solvers and analyzing the data with the partial least squares-structural equation modeling (PLS-SEM) approach, our study finds that point fosters crowdsourcing participation through distributive and interactional justice. Feedback enhances participation through distributive, interactional and informational justice. While social network strengthens participation via interactional and informational justice. Our study offers significant theoretical contributions and practical implications for the gamified crowdsourcing and organizational justice literatures

Nitrogen fertilization modifies organic transformations and coatings on soil biogeochemical interfaces through microbial polysaccharides synthesis

The soil-water interfaces (SWI) in soil pores are hotspots for organic matter (OM) transformation. However, due to the heterogeneous and opaque nature of soil microenvironment, direct and continuous tracing of interfacial reactions, such as OM transformations and formation of organo-mineral associations, are rare. To investigate these processes, a new soil microarray technology (SoilChips) was developed and used. Homogeneous 800-μm-diameter SoilChips were constructed by depositing a dispersed Oxisol A horizon suspension on a patterned glass. Dissolved organic matter from the original soil was added on the SoilChips to mimic SWI processes. The effects of ammonium fertilization (90 mg N kg−1 soil) on chemical composition of SWIs were evaluated via X-ray photoelectron spectroscopy. Over 21 days, ammonium addition increased OM coatings at SWIs and modified the OM chemical structure with more alcoholic- and carboxylic-C compared to the unfertilized control. Molecular modeling of OM composition at SWIs showed that N fertilization mainly facilitated the microbial production of glucans. We demonstrated that N availability modifies the specific OM molecular processing and its immobilization on SWIs, thereby providing a direct insight into biogeochemical transformation of OM at micro-scale. © 2019, The Author(s)

Povećanje stabilnosti i antioksidacijske aktivnosti antocijana iz ploda duda aciliranjem s jantarnom kiselinom

Research background. Anthocyanins possess valuable health-promoting activities with significant health benefits for humans. However, their instability is a limiting factor for their usage in functional foods and beverages. Experimental approach. In this work, a new method to enhance the stability of anthocyanins from mulberry fruit through acylation by using succinic acid as a selected acyl donor was explored. The Box-Behnken design of response surface methodology was applied to determine the optimized conditions for the acylation process. Results and conclusions. The highest acylation conversion rate was 79.04% at anthocyanins to succinic acid mass ratio 1:8.96, acylation duration 3 h and temperature 50 °C. Structural analysis of acylated anthocyanins revealed that succinic acid introduces a C-O-C bond and a hydroxyl group. The thermostability and light stability of mulberry anthocyanins were significantly improved after acylation, and the antioxidant activity expressed as total reducing power and Fe2+-chelating capacity of the acylated anthocyanins was also enhanced. Novelty and scientific contribution. Succinic acid acylation provides a novel method for stabilizing mulberry anthocyanins, as evidenced by the increased stability and antioxidant ability of anthocyanins, and thus facilitates its use in the food and nutraceutical industries.Pozadina istraživanja. Antocijani imaju pozitivni učinak na ljudsko zdravlje, no njihova im nestabilnost ograničava uporabu u proizvodnji funkcionalne hrane i pića. Eksperimentalni pristup. U ovom je radu ispitana nova metoda povećanja stabilnosti antocijana iz ploda duda aciliranjem s jantarnom kiselinom kao donorom acilne skupine. Optimalni uvjeti reakcije određeni su pomoću Box-Behnkenovog statističkog plana i metodom odzivnih površina. Rezultati i zaključci. Najveći postotak konverzije od 79,04 % postignut je pri masenom omjeru antocijana i jantarne kiseline od 1:8,96; trajanju acilacije od 3 h i temperaturi od 50 °C. Analizom strukture aciliranih antocijana utvrđeno je da sadržavaju C-O-C vezu i hidroksilnu skupinu iz jantarne kiseline. Aciliranje je bitno povećalo stabilnost antocijana pri izlaganju povišenim temperaturama i svjetlosti, te njihovu antioksidacijsku aktivnost, izraženu kroz ukupnu reducirajuću snagu i sposobnost keliranja Fe2+ iona. Novina i znanstveni doprinos. Aciliranje jantarnom kiselinom predstavlja novu metodu stabilizacije antocijana iz duda, što potvrđuje njihova povećana stabilnost i antioksidacijska sposobnost, čime je olakšana njihova primjena u proizvodnji hrane i nutraceutika

Shell microstructures (disturbance lines) of Arctica islandica (Bivalvia): a potential proxy for severe oxygen depletion

The spread of oxygen deficiency in nearshore coastal habitats endangers benthic communities. To better understand the mechanisms leading to oxygen depletion and eventually hypoxia, predict the future development of affected ecosystems, and define suitable mitigation strategies requires detailed knowledge of the dissolved oxygen (DO) history. Suitable high-resolution DO archives covering coherent time intervals of decades to centuries include bivalve shells. Here, we explored if the microstructure, specifically disturbance lines, in shells of Arctica islandica from the Baltic Sea can be used as an alternative or complementary proxy to Mn/Cashell to track the frequency and severity of past low-DO events. Disturbance lines differ from periodic annual growth lines by the presence of fine complex crossed lamellae instead of irregular simple prisms. Aside from a qualitative assessment of microstructural changes, the morphology of individual biomineral units (BMUs) was quantitatively determined by artificial intelligence-assisted image analysis to derive models for DO reconstruction. As demonstrated, Mn-rich disturbance lines can provide a proxy for past deoxygenation events (i.e., DO < 45 µmol/L), but it currently remains unresolved if low DO leads to microstructurally distinct features that differ from those caused by other environmental stressors. At least in studied specimens from the Baltic Sea and Iceland, low temperature, salinity near the lower physiological tolerance, or food scarcity did not result in disturbance lines. With decreasing DO supply, disturbance lines seem to become more prominent, contain more Mn, and consist of increasingly smaller and more elongated BMUs with a larger perimeter-to-area ratio. Although the relationship between DO and BMU size or elongation was statistically significant, the explained variability (<1.5%) was too small and the error too large to reconstruct DO values. BMU parameters may reveal a closer relationship with DO if studied in three dimensions and if the DO content was determined at high resolution, directly at the position where the bivalves lived, something that future work should address

Ndrg2 regulates vertebral specification in differentiating somites

AbstractIt is generally thought that vertebral patterning and identity are globally determined prior to somite formation. Relatively little is known about the regulators of vertebral specification after somite segmentation. Here, we demonstrated that Ndrg2, a tumor suppressor gene, was dynamically expressed in the presomitic mesoderm (PSM) and at early stage of differentiating somites. Loss of Ndrg2 in mice resulted in vertebral homeotic transformations in thoracic/lumbar and lumbar/sacral transitional regions in a dose-dependent manner. Interestingly, the inactivation of Ndrg2 in osteoblasts or chondrocytes caused defects resembling those observed in Ndrg2−/− mice, with a lower penetrance. In addition, forced overexpression of Ndrg2 in osteoblasts or chondrocytes also conferred vertebral defects, which were distinct from those in Ndrg2−/− mice. These genetic analyses revealed that Ndrg2 modulates vertebral identity in segmented somites rather than in the PSM. At the molecular level, combinatory alterations of the amount of Hoxc8-11 gene transcripts were detected in the differentiating somites of Ndrg2−/− embryos, which may partially account for the vertebral defects in Ndrg2 mutants. Nevertheless, Bmp/Smad signaling activity was elevated in the differentiating somites of Ndrg2−/− embryos. Collectively, our findings unveiled Ndrg2 as a novel regulator of vertebral specification in differentiating somites

Defense Responses to Short-term Hypoxia and Seawater Acidification in the Thick Shell Mussel Mytilus coruscus

The rising anthropogenic atmospheric CO2 results in the reduction of seawater pH, namely ocean acidification (OA). In East China Sea, the largest coastal hypoxic zone was observed in the world. This region is also strongly impacted by ocean acidification as receiving much nutrient from Changjiang and Qiantangjiang, and organisms can experience great short-term natural variability of DO and pH in this area. In order to evaluate the defense responses of marine mussels under this scenario, the thick shell mussel Mytilus coruscus were exposed to three pH/pCO2 levels (7.3/2800 μatm, 7.7/1020 μatm, 8.1/376 μatm) at two dissolved oxygen concentrations (DO, 2.0, 6.0 mg L−1) for 72 h. Results showed that byssus thread parameters, such as the number, diameter, attachment strength and plaque area were reduced by low DO, and shell-closing strength was significantly weaker under both hypoxia and low pH conditions. Expression patterns of genes related to mussel byssus protein (MBP) were affected by hypoxia. Generally, hypoxia reduced MBP1 and MBP7 expressions, but increased MBP13 expression. In conclusion, both hypoxia and low pH induced negative effects on mussel defense responses, with hypoxia being the main driver of change. In addition, significant interactive effects between pH and DO were observed on shell-closing strength. Therefore, the adverse effects induced by hypoxia on the defense of mussels may be aggravated by low pH in the natural environments

FATIGU TEST AND PARAMETRIC STUDY OF CRACKED STEEL PLATES REPAIRED BY CFRP

At the thin steel plates running a period,cracks may occur at the material or weld,and traditional repair methods aren’t suitable for cracks repair of the thin steel plates.But the method of drilling hole at the crack tip and pasting CFRP on the steel plates is a choice for crack repair.Firstly,through five groups of fatigue test,it analyzed the effect of the crack fatigue life of the hole joint CFRP reinforcement and the other methods.Then,based on the cohesive force theory,it established the finite element model of notch steel plate reinforced with CFRP.With the finite element model,it studied the repair parameters of the stiffness,length and width of CFRP.The results demonstrate that the remaining fatigue life of the hole joint CFRP reinforcement is better than drilling holes or pasting CFRP,and even more than the steel plate with no crack.So it is especially suitable for the thin-wall steel plate with short cracks

Anti-predatory responses of the thick shell mussel Mytilus coruscus exposed to seawater acidification and hypoxia

Ocean acidification and hypoxia, both caused by anthropogenic activities, have showed deleterious impacts on marine animals. However, their combined effect on the mussel's defence to its predator has been poorly understood, which hinders us to understand the prey-predator interaction in marine environment. The thick shell mussel Mytilus coruscus and its predator, the Asian paddle crab Charybdis japonica were exposed to three pH levels (7.3, 7.7, 8.1) at two concentrations of dissolved oxygen (2.0 mg/L, 6.0 mg/L) seawater. The anti-predatory responses of mussels, in terms of byssus thread production were analysed after 72 h exposure. During the experiment, frequency of shedding stalks (mussels shed their byssal stalks to release themselves from attachment and allow locomotion) and number of byssus threads increased with time, were significantly reduced by hypoxia and low pH levels, and some interactions among time, predator, DO and pH were observed. As expected, the presence of the crab induced an anti-predator response in M. coruscus (significant increases in most tested parameters except the byssus thread length). Acidification and hypoxia significantly reduced byssus thread diamter at the end of the experiment, but not the byssus thread length. Cumulative byssus thread length and volume were significantly impaired by hypoxia and acidification. Our results highlight the significance of anti-predatory responses for adult mussel M. coruscus even under a stressful environment in which stress occurs through ocean acidification and hypoxia. By decreasing the strength of byssus attachment, the chance of being dislodged and consumed by crabs is likely increased. Our data suggest that there are changes in byssus production induced by hypoxia and acidification, which may affect predation rates on M. coruscus in the field