Bi-DexHands: Towards Human-Level Bimanual Dexterous Manipulation.

Achieving human-level dexterity in robotics remains a critical open problem. Even simple dexterous manipulation tasks pose significant difficulties due to the high number of degrees of freedom and the need for cooperation among heterogeneous agents (e.g., finger joints). While some researchers have utilized reinforcement learning (RL) to control a single hand in manipulating objects, tasks that require coordinated bimanual cooperation are still under-explored due to the fewer suitable environments, which can result in difficulties and sub-optimal performance. To address these challenges, we introduce Bi-DexHands, a simulator with two dexterous hands featuring 20 bimanual manipulation tasks and thousands of target objects, designed to match various levels of human motor skills based on cognitive science research. We developed Bi-DexHands in Issac Gym, enabling highly efficient RL training at over 30,000 frames per second using a single NVIDIA RTX 3090. Based on Bi-DexHands, we present a comprehensive evaluation of popular RL algorithms in different settings, including single-agent/multi-agent RL, offline RL, multi-task RL, and meta RL. Our findings show that on-policy algorithms, such as PPO, can master simple manipulation tasks that correspond to those of 48-month-old babies, such as catching a flying object or opening a bottle. Furthermore, multi-agent RL can improve the ability to perform manipulations that require skilled bimanual cooperation, such as lifting a pot or stacking blocks. Despite achieving success in individual tasks, current RL algorithms struggle to learn multiple manipulation skills in most multi-task and few-shot learning scenarios. This highlights the need for further research and development within the RL community.

Association between screen time and depressive symptoms in a sample of Chinese medical students: Mediator role of empathy.

Medical students are at high risk of psychological subhealth under heavy stress with increasing screen time. This study aimed to explore the association between screen time and depressive symptoms and determine empathy as a mediating factor. In this cross-sectional study, a total of 945 medical students were surveyed, and 924 medical students were ultimately included after standard exclusion criteria. They reported their daily screen time and completed the Chinese version of the Jefferson Scale of Empathy-Student Version (JSE-S) and the Self-Rating Depression Scale (SDS). t tests and analysis of variance showed a significant difference in empathy and depressive symptoms by sex, stage, and screen time. The correlation analysis revealed that both affective and cognitive empathy have inverse associations with depressive symptoms. The mediation model confirmed that cognitive empathy played a positive mediating role between screen time and depressive symptoms, reducing the impact of screen time on depressive symptoms. Our study may add empirical evidence to prevent and intervene in depressive symptoms. These findings call for considering controlling screen time and enhancing cognitive empathy as interventions for medical students' depressive symptoms.

Bullying victimization and suicide attempts among adolescents in 41 low- and middle-income countries: Roles of sleep deprivation and body mass.

Background: Suicide is the fourth leading cause of death for adolescents, and globally, over 75% of completed suicides occur in low- and middle-income countries (LMICs). Bullying has been proven to be closely related to suicide attempts. However, further understanding of the mechanisms underlying the relationship between bullying and adolescents' suicide attempts is urgently needed. Methods: We used data from the Global School-based Student Health Survey (GSHS) (2010-2017) from 41 LMICs or regions. This study was based on questions assessing bullying victimization, suicide attempts, sleep deprivation, and body mass. Chi-square tests were used to explore the correlations among the main variables. The mediating role of sleep deprivation and the moderating role of body mass index (BMI) were analyzed using PROCESS. Results: The results showed a positive association between bullying victimization and suicide attempts. Sleep deprivation partially mediated the relationship between the frequency of being bullied and suicide attempts. In addition, sleep deprivation played a full or partial mediating role in the relationship between different types of bullying and suicide attempts. BMI moderated the relationships between the frequency of being bullied and suicide attempts, between being made fun of about one's body and sleep deprivation, and between sleep deprivation and suicide attempts. Conclusion: Being bullied has a positive effect on suicide attempts, which is mediated by sleep deprivation and moderated by body mass. The results of this study are consistent with the stress-diathesis model of suicide, suggesting that being bullied is one of the stressors of suicide in adolescents, while sleep deprivation and body mass are susceptibility diatheses of suicide. The results are conducive to identifying adolescents at a high risk of suicide, suggesting that there is a need to pay more attention to bullied adolescents, especially their sleep quality and body mass, and design effective intervention measures to improve the current situation of adolescent suicide in LMICs.

Effects of Dietary Phosphorus Levels on Growth Performance, Phosphorus Utilization and Intestinal Calcium and Phosphorus Transport-Related Genes Expression of Juvenile Chinese Soft-Shelled Turtle (Pelodiscus sinensis).

A 60-day feeding trial was performed to assess the effects of dietary phosphorus levels on growth performance, body composition, phosphorus utilization, plasma physiological parameters and intestinal Ca and P transport-related gene expression of juvenile Chinese soft-shelled turtle (P. sinensis). Four diets containing available P at graded levels of 0.88%, 1.00%, 1.18% and 1.63% (termed as D0.88, D1.00, D1.18 and D1.63, respectively) were formulated and each diet was fed to turtles (5.39 ± 0.02 g) in sextuplicate. The turtles were randomly distributed to 24 tanks with 8 turtles per tank. The results indicated that final body weight, specific growth rate, feed conversion ratio and protein efficiency ratio performed best in turtles fed 1.00% available P diet. The crude lipids of the whole body exhibited a decreasing trend with the dietary available P, whereas the calcium and phosphorus of the whole body and bone phosphorus showed an opposite tendency. The apparent digestibility coefficient of phosphorus declined with the dietary available P. Turtles fed 1.00% available phosphorus had the highest phosphorus retention ratio compared with other treatments. Simultaneously they had significantly lower phosphorus loss than turtles fed D1.18 and D1.63 and had no differences in this respect from turtles fed a low-phosphorus diet. It was noteworthy that the lowest plasma calcium concentrations, and alkaline phosphatase activities in plasma and liver, were discovered in turtles fed the diet containing 1.63% available phosphorus. In addition, the high-phosphorus diet resulted in significantly down-regulated expression of intestinal phosphorus and calcium transport-related key genes. In conclusion, the available phosphorus requirement of juvenile P. sinensis was determined at 1.041% (total phosphorus was 1.80%) based on quadratic regression of weight gain rate, and excessive dietary phosphorus stunted turtle growth possibly via inhibiting intestinal calcium absorption.

Parental care and depressive symptoms among Chinese medical students: roles of empathy and gender.

BACKGROUND: Medical students in China who face the dual pressure of study and employment tend to experience subclinical depressive symptoms. Parental care plays an important direct and indirect role in the psychological development of medical students, and the extent and mechanism of this role urgently need to be studied and discussed. METHODS: After simple random sampling and screening of valid questionnaires, data from a total of 924 people were used. The participants completed the parental bonding instrument, self-rating depression scale, Chinese version of the Jefferson empathy scale-medical student edition and self-rating anxiety scale to evaluate parental care, empathy, depressive symptoms and anxiety. The data were statistically processed using a descriptive analysis, correlation analysis and test of moderated mediation. RESULTS: Maternal care had a significant negative predictive effect on depressive symptoms among medical students. Strong maternal care can reduce the occurrence of depressive symptoms in medical students. Empathy played a positive mediating role such that both types of empathy could alleviate the effect of weak maternal care on the depressive symptoms of medical students. However, neither cognitive empathy nor affective empathy played a mediating role in the relationship between paternal care and depressive symptoms. Nevertheless, the relationship between maternal care and empathy was moderated by the medical students' gender. CONCLUSIONS: The effect of this relationship on female medical students deserves special attention. The results of this study provide a reference and basis for the adjustment of medical education. This study could also help in the design of effective psychological intervention measures to reduce the degree of depressive symptoms and enhance personal empathy.

Associations of affective and cognitive empathy with depressive symptoms among a sample of Chinese college freshmen.

BACKGROUND: College freshmen are at high risk for mental and socioemotional problems after entering a new environment. However, few investigators have evaluated the associations between empathy and depressive symptoms among college freshmen. The present study examined the presence and associations of affective and cognitive empathy with depressive symptoms among college freshmen in China. METHODS: In total, 4297 college freshmen completed the Interpersonal Reactivity Index as an assessment of empathy and the University Personality Inventory to evaluate the prevalence of depressive symptoms. RESULTS: The empathy scores of females were higher than that of males, and approximately 18.4% of freshmen had high-depressive symptoms (HDS). Freshmen with a higher positive component of affective empathy (empathic concern (EC)) experienced fewer HDS. In contrast, freshmen with a higher negative component of affective empathy (personal distress (PD)) and lower cognitive empathy (perspective taking (PT)) experienced more HDS. EC was negatively associated with depressive symptoms, PD was positively related to depressive symptoms, and PT was negatively associated with depressive symptoms. Males with a higher degree of PT experienced fewer HDS, while females with a higher degree of PT experienced more HDS. CONCLUSION: Affective empathy was positively associated with depressive symptoms, while cognitive empathy was negatively related to depressive symptoms. The association between affective and cognitive empathy with depressive symptoms may add some support to the detection of clinical depressive symptoms. These findings call for the necessity of considering the characteristics of affective and cognitive empathy as a crucial concern in the prevention of depressive symptoms.

Association between parental control and subclinical depressive symptoms in a sample of college freshmen: Roles of empathy and gender.

BACKGROUND: College freshmen are at high-risk for depressive symptoms after experiencing drastic transitions in a new environment. Perceived parental control has proved as a prominent role in an adolescent's mental health. However, the further understandings of the mechanisms underlying the relation between perceived parental control and freshmen's depressive symptoms are urgent. METHODS: A total of 4,297 Chinese freshmen (57% female) were recruited. They completed the self-report Parental Bonding Instrument (PBI), Interpersonal Reactivity Index (IRI), and University Personality Inventory (UPI), which assess parental control, empathy and depressive symptoms, respectively. The data were analysed using correlation analysis and a test of moderated mediation. RESULTS: The results showed positive association between parental control and depressive symptoms, partially mediated by empathy. The relation between parental control and affective empathy, was moderated by gender. Specifically, maternal control had a more significant positive effect on males' personal distress. Moreover, the influence of paternal control was also greater for males, with a negative effect on empathic concern and positive on personal distress. CONCLUSIONS: Parental control significantly positively predicted college freshmen's depressive symptoms, and empathy played a partially mediating role. In addition, the relations between parental control and affective empathy were moderated by freshmen's gender. The findings of this study provide a better understanding of how parental control is related to freshmen's depressive symptoms, offering a theoretical basis for promoting the development of adolescents' mental health and supporting the design of effective psychological interventions to relieve their depressive symptoms.