Recommender Systems (RSs) are becoming increasingly popular in the last years. They collect reviews concerning several types of items (e.g., shops, professionals, services, songs or videos) in order ...to rank them according to a given criterion, and to suggest the most relevant ones to their users. However, most of the currently used RSs exhibit two main drawbacks: they are based on a centralized control model and they do not provide reward mechanisms to encourage the participation of users. To deal with these challenges, the architectures of current RSs could be enhanced through blockchain technology, thus providing novel solutions to decentralize them. As a matter of fact, the blockchain technology could be successfully adopted in this context because smart contracts would allow the decentralization of system control, while cryptocurrency and tokens could be used to implement the reward mechanism.
In the light of the above considerations, this manuscript presents a decentralized rating framework aimed to support the users of RSs based on blockchain technology, providing a token-based reward mechanism that remunerates users submitting their reviews to incentivize their participation. Moreover, the proposed system provides a flexible strategy to rank items, allowing users to choose among different functions to combine reviews to obtain item ranking. The performance and the cost of using the proposed system have been evaluated on the Ropsten Ethereum test network. For instance, our experiments have shown that the median time required to store a batch of 35 ratings is about 47 s, while the average time required to obtain the score of an item having 6000 ratings is less than 2.5 s.
•A general blockchain based framework is proposed to support Recommender Systems.•Blockchain provides system decentralization, review immutability and persistency.•Our framework does not require any trusted entity to operate.•Tokens are used to reward the users for their reviews based on their experience.•An Ethereum implementation is developed to validate the framework.
Tipping, as a new model of content monetization, is being adopted widely. Leveraging the policy changes in one of the largest social media platforms, we examined when and how tip-based content ...monetization incentives work. We adopt framing theory to explain different attitudes toward content monetization incentives between status-framed and benefit-framed users. Our results show that a hierarchical content monetization program decreases status-framed users' content contribution, whereas a general accessible content monetization program will effectively motivate the content supply of all users. Moreover, we identify the underlying mechanisms for heterogeneous content monetization effects by unbinding signaling and rewarding effects of tipping feature.
The Individual Low-carbon Behavior Rewarding System (ILBRS) is a new Chinese environmental policy that aims to guide public participation in sustainable development through applying a range of ...incentive mechanisms. It is regarded as an important and effective way of reducing carbon emissions in response to climate change. However, knowledge of the influencing factors of support for the ILBRS is still scattered and lacks systematic analysis. This study is one of the first literatures to explore public support for ILBRS through a large sample of longitudinal data relying on psychological theory. Based on the Responsible Environmental Behavior model, we established a mechanism that consists of three levels of factors affecting public support for the ILBRS. These factors involve individual characteristics, individual perception, and willingness of performing other low-carbon behaviors. The results of a longitudinal panel survey at one-year interval with 2,324 valid responses indicated that connectedness to nature, perception that climate change is happening, willingness to sort waste and to use green energy could significantly and positively predict public support for the ILBRS. Based on the findings of this study, we provide practical suggestions for policy makers to further improve the implementation of the ILBRS by raising public awareness of climate change and integrating it with other relevant environmental policies.
Background
Previous gene–environment interaction studies of CU traits have relied on the candidate gene approach, which does not account for the entire genetic load of complex phenotypes. Moreover, ...these studies have not examined the role of positive environmental factors such as warm/rewarding parenting. The aim of the present study was to determine whether early warm/rewarding parenting moderates the genetic contributions (i.e., heritability) to callous–unemotional (CU) traits at school age.
Methods
Data were collected in a population sample of 662 twin pairs (Quebec Newborn Twin Study – QNTS). Mothers reported on their warm/rewarding parenting. Teachers assessed children's CU traits. These reports were subjected to twin modeling.
Results
Callous–unemotional traits were highly heritable, with the remaining variance accounted for by nonshared environmental factors. Warm/rewarding parenting significantly moderated the role of genes in CU traits; heritability was lower when children received high warm/rewarding parenting than when they were exposed to low warm/rewarding parenting.
Conclusions
High warm/rewarding parenting may partly impede the genetic expression of CU traits. Developmental models of CU traits need to account for such gene–environment processes.
The COVID-19 global pandemic will likely change how organizations conduct business. For example, a white paper from McKinsey claims that flexible and remote work arrangements (e.g., ...“working-from-home”) will become increasingly frequent in the “new normal” that will follow the COVID-19 pandemic. Our work is motivated by the premise that in a post-pandemic workplace, traditional management practices like unilaterally assigning goals and displaying contingent rewarding behaviors will likely be replaced by positive management practices. In this context, positive management practices include allowing employees to self-set their goals and displaying authentic leadership behaviors while managing them. However, whether these positive management practices are more efficient in sustaining performance is unknown. Our study benchmarked positive management practices against traditional management practices in a remote work environment, using three individual performance metrics: goal attainment, goal commitment, and perceived task efficacy. In a panel laboratory experiment consisting of a baseline measurement and two work sessions, we randomly assigned participants to an authentic vs. transactional leadership condition (amateur actor recording) and one of three possible goal-setting types (assigned, self-set, “do-your-best”). Our results show that participants in the authentic leadership × self-set goals condition outperformed all other experimental conditions. Further, a
post hoc
analysis revealed a serial mediation effect of (a) goal attainment and (b) goal commitment at time 1 on perceived task efficacy reports at time 2.
Orexinergic neurons, which are closely associated with narcolepsy, regulate arousal and reward circuits through the activation of monoaminergic neurons. Psychostimulants as well as 5-HT-related ...compounds have potential in the treatment of human narcolepsy. Previous studies have demonstrated that orexin receptor antagonists as well as orexin deficiencies affect the pharmacological effects of psychostimulants. However, little information is available on the consequences of psychostimulant use under orexin deficiency. Therefore, the present study was designed to investigate the abuse liability of psychostimulants in orexin knockout (KO) mice. In the present study, conditioned place preferences induced by methamphetamine and methylphenidate were not altered in orexin KO mice. Interestingly, we found that MDMA induced a conditioned place preference in orexin KO mice, but not in wild type (WT) mice. In addition, MDMA produced methylphenidate/methamphetamine-like discriminative stimulus effects in orexin KO mice, but not WT mice. Increases in 5-HT and dopamine release in the nucleus accumbens induced by MDMA were not altered by knockout of orexin; the steady-state level of G protein activation was higher in the limbic forebrain of orexin KO mice. In substitution tests using a drug discrimination procedure, substitution of 5-HT1A receptor agonist for the discriminative stimulus effects of methylphenidate was enhanced in orexin KO mice. These findings indicate that the orexinergic system is involved the rewarding effects of psychostimulants. However, there is a risk of establishing rewarding effects of psychostimulants even under orexin deficiency. On the other hand, deficiencies in orexin may enhance the abuse liability of MDMA by changing a postsynaptic signal transduction accompanied by changes in discriminative stimulus effects themselves.
Highlights • TLR4 participates in ethanol-induced long-term aberrant synaptic remodeling in the adolescence. • TLR4 is involved in ethanol-induced epigenetic changes in the adolescence. • TLR4 ...participates in ethanol-induced long-term rewarding and anxiety effects in the adolescence.
Rationale
Relapse into substance use is often triggered by exposure to drug-related environmental cues. The magnitude of drug seeking depends on the duration of abstinence, a phenomenon known as the ...incubation of drug craving. Clinical and preclinical research shows that the insular cortex is involved in substance use disorders and cue-induced drug seeking. However, the role of the insula on memory retrieval and motivational integration for cue-elicited drug seeking remains to be determined.
Objectives
We investigated the role of the anterior insular cortex (aIC) and its glutamatergic projection to amygdala nuclei (aIC-AMY) on the expression of conditioned place preference (CPP) during early and late abstinence.
Methods
Male adult C57BL/6J mice underwent amphetamine-induced CPP, and their preference was tested following 1 or 14 days of abstinence. aIC and aIC-AMY functional role in CPP expression was assessed at both abstinence periods by employing optogenetic silencing and behavioral pharmacology.
Results
Compared to a single day, an exacerbated preference for the amphetamine-paired context was observed after 14 days of abstinence. Photoinhibition of either aIC or aIC-AMY projection reduced CPP expression following late but not early abstinence. Similarly, the antagonism of aIC NMDA receptors reduced CPP expression after 14 days of abstinence but not 1 day.
Conclusions
These results suggest that aIC and its glutamatergic output to amygdala nuclei constitute critical neurobiological substrates mediating enhanced motivational cue reactivity during the incubation of amphetamine craving rather than contextual memory recall. Moreover, cortical NMDA receptor signaling may become sensitized during abstinence, ultimately modulating disproportioned drug seeking.
To confirm the relationship between pro‐social behaviour and increased physical functioning revealed by previous researchers in Western samples, we conducted four experiments with 378 Chinese ...undergraduates. The participants' strength to hold, to grip and to lift, as well as their vitality (walking speed), were measured after thinking of acts of kindness. The results showed that recalling pro‐social behaviour (helping others or spending money on others) that had occurred in the past or imagining pro‐social behaviour happening in the future imbued people with more physical strength and vitality. In three experiments, pro‐social behaviour boosted the positive mood of the actors, but the effect was only significant in one experiment, suggesting that the hidden gift may include increased happiness, but that enhanced physical functioning cannot be accounted for by differences in emotions. These results add to the evidence that the function of pro‐social behaviour in promoting physical functioning may be culturally universal.
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