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According to previous theories of aggression, positive outcome expectancy for aggression can predict aggression, while moral disengagement and negative outcome expectancy for aggression may, respectively, serve as mediators and moderators in this prediction process. To test the hypothesis, Study 1 first developed the Aggression Outcome Expectancy Questionnaire and examined its two-factor structure, which consists of positive and negative outcome expectancy for aggression. Next, 677 college students were recruited to participate in Study 2 and were asked to complete the Aggression Outcome Expectancy Questionnaire, Civic Moral Disengagement Questionnaire, and Buss–Perry Aggression Questionnaire. The findings indicated the following: (1) The Aggression Outcome Expectancy Questionnaire for college students demonstrated acceptable reliability and construct validity, confirming the two-factor structure of aggression outcome expectancy. (2) After controlling for sex and age, moral disengagement partially mediated the relationship between positive outcome expectancy and aggression. (3) Negative outcome expectancy for aggression moderated the effect of positive outcome expectancy on aggression, as well as moral disengagement. Specifically, negative outcome expectancy for aggression attenuated the positive predictive effect of positive outcome expectancy on aggression and moral disengagement. In conclusion, the present study extends our understanding of the motivational mechanism of aggression, offering a theoretical reference for preventing and intervening in aggressive behavior among college students.

The techniques that harvest mechanical energy from low-frequency, multidirectional environmental vibrations have been considered a promising strategy to implement a sustainable power source for wireless sensor networks and the Internet of Things. However, the obvious inconsistency in the output voltage and operating frequency among different directions may bring a hindrance to energy management. To address this issue, this paper reports a cam-rotor-based approach for a multidirectional piezoelectric vibration energy harvester. The cam rotor can transform vertical excitation into a reciprocating circular motion, producing a dynamic centrifugal acceleration to excite the piezoelectric beam. The same beam group is utilized when harvesting vertical and horizontal vibrations. Therefore, the proposed harvester reveals similar characterization in its resonant frequency and output voltage at different working directions. The structure design and modeling, device prototyping and experimental validation are conducted. The results show that the proposed harvester can produce a peak voltage of up to 42.4 V under a 0.2 g acceleration with a favorable power of 0.52 mW, and the resonant frequency for each operating direction is stable at around 3.7 Hz. Practical applications in lighting up LEDs and powering a WSN system demonstrate the promising potential of the proposed approach in capturing energy from ambient vibrations to construct self-powered engineering systems for structural health monitoring, environmental measuring, etc.

In order to collect mechanical energy from human motions on pavement without an obvious disturbance, a piezoelectric harvester for small displacement is proposed. A seesaw mechanism is utilized to transmit the pressure displacement to piezoelectric beams. Benefitting from the superiority of used axially deformed beams, the designed scheme can produce a higher voltage than the ones based on the conventional bending cantilever. Favorable electrical energy is achieved by the manufactured prototype under a displacement lower than 1 mm. Two practical applications, including charging a capacitor and powering an environmental sensing node, demonstrate the feasibility of this energy harvester in supplying power for engineering devices. The proposed device shows a favorable capacity to capture energy from humans walking on pavements. Also, this category of axially deformed beam could provide ideas for developing piezoelectric harvesters under small displacements.

Wetland plants are important components in constructed wetlands (CWs), and one of their most important functions in CWs is to purify the water. However, wetland plant litter can also increase eutrophication of water via decomposition and nutrient release, and few studies have focused on the interspecific variation in the decomposition rate and nutrient release of multiple plant species in CWs. Here a greenhouse litter-bag experiment was conducted to quantify the decomposition rates and nutrient release of 7 dominant macrophytes (2 floating plants and 5 emergent plants) in three types of water substrate. The results showed that plant litter species and growth forms significantly affected the litter mass losses. The nutrient release was significantly different among plant litter species, but not between floating and emergent plants. Litter traits, such as litter lignin, total nitrogen (TN) and total phosphorus (TP) can well predict the decomposition rates of submerged litter. These results indicated that submerging litter in water did not change the relationships between litter traits and litter decomposition rates, and leaching might play a more important role in the decomposition of submerged litter in CWs than that in other terrestrial ecosystems. These findings can provide suggestions for managers about the maintenance of constructed wetlands.

We monitored the water quality and hydrological conditions of a horizontal subsurface constructed wetland (HSSF-CW) in Beijing, China, for two years. We simulated the area-based constant and the temperature coefficient with the first-order kinetic model. We examined the relationships between the nitrogen (N) removal rate, N load, seasonal variations in the N removal rate, and environmental factors—such as the area-based constant, temperature, and dissolved oxygen (DO). The effluent ammonia (NH4+-N) and nitrate (NO3−-N) concentrations were significantly lower than the influent concentrations (p < 0.01, n = 38). The NO3−-N load was significantly correlated with the removal rate (R2 = 0.96, p < 0.01), but the NH4+-N load was not correlated with the removal rate (R2 = 0.02, p > 0.01). The area-based constants of NO3−-N and NH4+-N at 20 °C were 27 ± 26 (mean ± SD) and 14 ± 10 m∙year−1, respectively. The temperature coefficients for NO3−-N and NH4+-N were estimated at 1.004 and 0.960, respectively. The area-based constants for NO3−-N and NH4+-N were not correlated with temperature (p > 0.01). The NO3−-N area-based constant was correlated with the corresponding load (R2 = 0.96, p < 0.01). The NH4+-N area rate was correlated with DO (R2 = 0.69, p < 0.01), suggesting that the factors that influenced the N removal rate in this wetland met Liebig’s law of the minimum.