Contrasting response of comammox Nitrospira, ammonia oxidising bacteria, and archaea to soil pH and nitrogen inputs.

This study aimed to investigate the effect of soil pH change, and nitrogen amendment on ammonia oxidiser abundance and comammox Nitrospira community composition. The experimental design used soil mesocosms placed in a temperature-controlled incubator for 90 days. A Templeton silt loam was used as its physiochemical properties are typical of the region's dairy farms. The results showed that comammox Nitrospira clade B preferred the natural (pH 6.1-6.2) soil pH with no applied nitrogen. Furthermore, synthetic urine (N700) decreased the abundance of comammox Nitrospira clade B. This may have been because the large amounts of available ammonia in the N700 treatments inhibited the growth of comammox Nitrospira. These results suggest that while comammox Nitrospira clade B are present in New Zealand dairy farm soils, but their role in nitrification in the very high nitrogen environment under a urine patch in grazed pastures may be limited. Further research is needed to confirm this. In contrast to comammox, the AOB community (dominated by Nitrosospira) responded positively to the application of synthetic urine. The response was greatest in the high pH soil (7.1), followed by the natural and then the low pH (4.9) soils. This may be due to the difference in ammonia availability. At high pH, the ammonia/ammonium equilibrium favours ammonia production. Calculated ammonia availability in the N700 treatments accurately predicted the AOB amoA gene abundance. Interestingly, the AOA community abundance (which was predominantly made up of Thaumarchaeota group I.1b clade E) seemed to prefer the natural and high pH soils over the low pH. This may be due to the specific lineage of AOA present. AOA did not respond to the application of nitrogen.

Development and validation of the Social Capital Assessment Tool in pregnancy for Maternal Health in Low and middle income countries (LSCAT-MH).

OBJECTIVES: Social capital which implies 'features of social organisation, such as trust, norms and networks that can improve the efficiency of society by facilitating coordinated actions' is rarely assessed in relation to maternal health in low/middle-income countries (LMICs). A main reason for this research gap could be the unavailability of a specific tool to measure social capital in pregnancy. The study developed and validated an instrument to measure social capital among pregnant women. SETTING: We developed the tool based on World Bank Social Capital Assessment Tool and its adaptations identified as applicable to LMIC from an initial systematic review. The study was conducted in Anuradhapura district in the North Central Province of Sri Lanka. Validation process was conducted in urban, rural and resettled communities. PARTICIPANTS: Study participants of the cognitive validation included pregnant women from the three communities, and an expert panel including a social scientist, methodological expert, subject expert, public health officers. The psychometric validation was performed on 439 pregnant women permanently residing in the three communities. RESULTS: The 24-item Low and middle income countries Social Capital Assessment Tool for Maternal Health (LSCAT-MH) demonstrated high internal consistency (Cronbach's α=0.94). Factor analytical methods suggested a four-factor model of (1) neighbourhood networks (structural bonding), (2) domestic and neighbourhood cohesion (cognitive bonding), (3) social contribution and (4) social participation (structural bridging). Concurrent validity with antenatal mental ill health was confirmed through a negative correlation with the Edinburgh Postpartum Depression Scale. Test-retest reliability was high with intraclass correlation of 0.71 and a Pearson correlation of 0.83. CONCLUSION: The LSCAT-MH is a psychometrically valid and reliable tool to measure social capital in pregnancy. Predictive validity was not tested as the study was not a longitudinal follow-up.