Microbial mechanisms of carbon and nitrogen acquisition in contrasting urban soils

© 2018 Elsevier Masson SAS Urban soils play an essential role in delivering ecosystem services due to soil microbial functions but there is limited evidence of the role of urban soils in the global carbon cycle. Inorganic nitrogen (N) reduces microbial respiration of soil organic matter (SOM) in pristine and managed forest soils but there is less evidence available on the extent to which this occurs in contrasting urban soils. This study examined the ephemeral effect of inorganic N and SOM (woodland versus grassland urban soil) on microbial functions represented by extracellular enzyme activities and microbial respiration of added substrates of contrasting quality. It was hypothesized that inorganic N stimulates extracellular enzyme activities and microbial respiratory responses to the addition of substrates varying in SOM quantity or quality. Results showed significantly higher SOM content, DOC and dissolved phenolic compounds in the woodland compared to grassland soil. In the woodland soil only, N addition increased β-glucosidase and N-acetyl-glucosaminidase enzyme activities and decreased microbial respiration responses to substrates. This suggests a microbial requirement for C acquisition dependent on N availability that reduced overflow respiration of the microbial community due to the composition of the woodland SOM pool. In conclusion, urban soils that contrast in vegetation types and hence OM content will likely differ mechanistically in response to increased N deposition and climate change altering their potential ability to store soil C in the future

Comparing the Efficacy of Drug Regimens for Pulmonary Tuberculosis: Meta-analysis of Endpoints in Early-Phase Clinical Trials

Background A systematic review of early clinical outcomes in tuberculosis was undertaken to determine ranking of efficacy of drugs and combinations, define variability of these measures on different endpoints, and to establish the relationships between them. Methods Studies were identified by searching PubMed, Medline, Embase, LILACS (Latin American and Caribbean Health Sciences Literature), and reference lists of included studies. Outcomes were early bactericidal activity results over 2, 7, and 14 days, and the proportion of patients with negative culture at 8 weeks. Results One hundred thirty-three trials reporting phase 2A (early bactericidal activity) and phase 2B (culture conversion at 2 months) outcomes were identified. Only 9 drug combinations were assessed on >1 phase 2A endpoint and only 3 were assessed in both phase 2A and 2B trials. Conclusions The existing evidence base supporting phase 2 methodology in tuberculosis is highly incomplete. In future, a broader range of drugs and combinations should be more consistently studied across a greater range of phase 2 endpoints

Risk of recurrence after a first seizure and implications for driving: further analysis of the Multicentre study of early Epilepsy and Single Seizures

Objective To determine for how long after a first unprovoked seizure a driver must be seizure-free before the risk of recurrence in the next 12 months falls below 20%, enabling them to regain their driving licence

Affect - an ethnocentric encounter?: Exploring the 'universalist' imperative of emotional/affectual geographies

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