The short-term and long-term effects of Fe(II) on the performance of anammox granules.

Fe(II) is one of the commonly used additives in wastewater treatment and proved to be beneficial for promoting microbial activity. In this study, the effects of Fe(II) on the specific anammox activity (SAA) and reactor performance were proved to be concentration-dependent. In the short-term experiment, low concentration of Fe(II) (5-80 mg/L) significantly enhanced the SAA, while high concentration of Fe(II) (120-300 mg/L) inhibited the SAA. It was confirmed that anammox can be domesticated after long-term exposure to low Fe(II) concentration, and the SAA could be further enhanced by higher Fe(II) concentration in the following phases. In addition, as an important factor for anammox granulation and maintaining the SAA, the extracellular polymeric substance (EPS) was also affected by Fe(II) addition. In spite of the effects on SAA and EPS, Fe(II) was proved to be the key factor that enhances the N2 O emission via abiotic pathway in the anammox reactor. PRACTITIONER POINTS: Low Fe(II) concentrations enhanced SAA, while high concentrations inhibited SAA. Long-term acclimatization by Fe(II) improved the tolerance of anammox to Fe(II). Fe(II) affects the amount and constituent of EPS and the performance of anammox granules. Accumulation of Fe(II) in the AAFEB reactor promoted the N2 O emission.

Dangers on the road: A longitudinal examination of passenger-initiated violence against bus drivers.

This study examined the impact of workplace violence against 109 bus drivers over a 1-year span. Workplace violence is related to both psychological and work-related consequences. Our findings showed that bus drivers experienced a wide range of violence at work and the psychological consequences were devastating: Half of the participants met the diagnostic criteria for acute stress disorder within the first month following the index event. Majority of them experienced at least moderate levels of post-traumatic stress disorder (PTSD) problems over the 1-year span. About 9.3% of participants showed a delayed onset of PTSD 6 months after. Furthermore, counter-supportive behaviours and reexposure to violence played important roles in the maintenance of PTSD symptoms over time. Even though PTSD symptoms per se did not relate to bus driver's confidence in coping with aggressive passengers, the immediate post-traumatic reaction-symptoms of acute stress disorder-showed a significant long-term negative effect on bus drivers' confidence in dealing with aggressive passengers 12 months after. This study provided empirical evidence of the changing nature of PTSD symptoms over time among bus drivers.

I see so I feel: Coping with workplace violence among victims and witnesses.

BACKGROUND: Workplace violence is a serious concern for workers' mental health and well-being in high risk work sectors. OBJECTIVE: This study examined victims' and witnesses' experiences after exposure to workplace violence, and the types of help they used to cope with the violent event. METHODS: Workers (n = 211) from five different work sectors participated in our study. Multiple mediation analysis was used to investigate the indirect effects through psychological and work consequences on victims' versus witnesses' differential likelihood of using formal, paraformal and informal helping. RESULTS: Results showed that workplace violence has detrimental effects on both victims and witnesses. Direct victims were more negatively affected psychologically and at work than witnesses. The indirect effect through psychological difficulty after experiencing workplace violence was significant in predicting formal helping. The indirect effect through reduced work functioning in predicting paraformal helping was also significant. No significant indirect effect was found in predicting informal helping. CONCLUSIONS: Both victims and witnesses used multiple types of helping to cope with the violent event. This study has practical implications on management and clinical practices for better organizations of resources in helping victims and witnesses to cope with workplace violence.

Social integration prospectively predicts changes in heart rate variability among individuals undergoing migration stress.

BACKGROUND: Poor social integration increases risk for poor health. The psychobiological pathways underlying this effect are not well-understood. PURPOSE: This study utilized a migration stress model to prospectively investigate the impact of social integration on change in high-frequency heart rate variability (HF-HRV), a marker of autonomic functioning. METHODS: Sixty new international students were recruited shortly after their arrival in the host country and assessed 2 and 5 months later. At each assessment period, participants provided information on social integration and loneliness and had their resting HF-HRV evaluated. RESULTS: There was an overall decrease in HF-HRV over time. The magnitude of the within-person and between-person effects of social integration on HRV increased over time, such that greater social integration was associated with higher HF-HRV at later follow-ups. CONCLUSIONS: These results suggest that altered autonomic functioning might represent a key pathway linking social integration to health outcomes.