Abortion in dairy cattle causes considerable economic losses to the dairy industry. Aborted fetuses and samples from the corresponding aborting dams from 12 dairy herds in Beijing were tested for 9 abortifacient infectious pathogens by PCR between 2008 and 2010. From a total of 80 abortion cases collected during this period, infectious agents were detected in 45 (56.3%) cases, 22 (48.9%) of which represented co-infections with two or three infectious agents. The detected pathogens included infectious bovine rhinotracheitis virus (36.3%) and Neospora caninum (31.3%), followed by bovine viral diarrhoea virus (7.5%), Brucella abortus (6.3%), Tritrichomonas foetus (5%) and Toxoplasma gondii (1.3%). Campylobacter fetus, Coxiella burnetii and Chlamydophila psittaci were not detected in any abortion case. Findings from this study indicated that infectious bovine rhinotracheitis virus and Neospora caninum were the main potential causes of abortions in Beijing dairy herds, whereas the bacterial pathogens were not, in contrast to reports from other countries. This is the first study to test nine abortifacient infectious agents by PCR at the same time, and it is also the first time to report the involvement of a variety of infectious agents in bovine abortion cases in China.
During the COVID-19 lockdown, problematic Internet use (PIU) has become a serious issue among residential college students, who remain physically isolated from off-campus society. This study constructs an integrated model to investigate the influencing mechanisms of internal locus of control (LOC) and objective peer effects.
Residential college students (n = 494) were surveyed from a single department of a Chinese university. An item from the World Value Survey was employed to measure internal LOC, while objective peer effects were assessed via friends’ mutual nominations. Finally, PIU was measured using Young’s Internet Addiction Tests, while a social network analysis and logit regression were combined to estimate various factors’ effects on PIU.
In our sample, the prevalence rate of PIU was 30.6%, and while internal LOC was a protective factor for PIU, its protective role was diluted when exposed to a peer environment with high PIU prevalence. Furthermore, indegree performed contrasting roles on PIU under various network conditions. It acted as a protective factor when exposed to a low prevalence of PIU in a peer environment; however, it became a risk factor when PIU peers were prevalent. Lastly, the protective efficacy of betweenness was activated when individuals had more than one PIU friend.
Discussion and conclusions
Further intervention studies focusing on individuals with a weak internal LOC are recommended during the lockdown. Additionally, interventions that consider the network structures carefully, may enhance the prevention of PIU.
Nonsuicidal self-injury (NSSI) is highly prevalent in adolescents and is associated with various mental health problems. Repetitive NSSI (R-NSSI), as an extreme manifestation of NSSI, is a growing concern and has been proposed as a behavioral addiction. However, little is known about the potential addictive mechanisms of NSSI. This study aimed to examine the mediating effect of emotion dysregulation and the moderating effect of impulsivity using the Interaction of Person-Affect-Cognition-Execution (I-PACE) model in adolescents who repeatedly engage in NSSI.
A total of 3,915 adolescents (mean age = 13.21 years, SD = 0.87, 57.6% male) were recruited from three middle schools. Relevant questionnaires were used to evaluate childhood maltreatment, emotion dysregulation, impulsivity, and NSSI. Mediation and moderated mediation analyses were conducted separately for adolescents with occasional NSSI (O–NSSI) and R-NSSI to assess the relationship between childhood maltreatment, emotion dysregulation, impulsivity, and NSSI frequency.
Our study found that childhood maltreatment was directly related to NSSI and indirectly related to NSSI through emotion dysregulation in both the R-NSSI and O–NSSI groups. Furthermore, impulsivity played a moderating role in the relationship between emotion dysregulation and NSSI in the R-NSSI group but not in the O–NSSI group.
Discussion and conclusions
The findings suggest that a high level of impulsivity and a high level of emotion dysregulation may be important risk addictive factors of NSSI through childhood maltreatment. Strengthening the emotion regulation skills and inhibitory control of adolescents with NSSI would be helpful to reduce their self-injury behaviors and maintain their mental health. This finding also supports the validity of the I-PACE model for evaluating R-NSSI.