Modelling response patterns of physico-chemical indicators during high-rate composting of green waste for suppression of Pythium ultimum.

High-rate composting studies on green waste, i.e. banana leaves (BL) and lawn clippings (LC), were conducted in 0.25-m3 rotary barrel composters to evaluate and model changes in key physico-chemical parameters during composting. Time to compost maturity and antagonistic effects and relationships of composts against Pythium ultimum were also investigated. Higher temperatures were achieved in LC compost (LCC), which did not translate to higher total organic carbon (TOC) loss but resulted in lower carbon to nitrogen ratio (C:N) and a more mature compost. With the exception of electrical conductivity (EC), net decreases were observed in pH, TOC and C:N across compost types. Total Kjeldahl nitrogen (TKN) showed a net increase in LCC and a net decrease in BLC. With the exception of TOC and pH, the results showed that compost type and time had a significant effect on the respective TKN, EC and C:N models. Compost temperature and TOC were best described by the critical exponential and rectangular hyperbola functions, respectively. Whereas TKN, C:N and pH were described using double Fourier functions and EC using Fourier functions. Composts achieved maturity within 19 days and significantly inhibited the growth of P. ultimum. Bacterial population was positively related to growth inhibition (GI) across compost types, whereas total microbial population had a positive relationship with GI in LCC. Evidence suggests that multiple groups of microorganisms contributed to GI through antibiosis and competition for resources. Composts were determined to be suitable for use as components of plant growth substrates based on compost maturity indices.

An empirically validated framework for measuring patient's acceptability of health care in Multi-Island Micro States.

Measuring health-care acceptability presents conceptual and contextual challenges, particularly in data-poor Multi-Island Micro States (MIMSs). Thus, there has been limited evidence on the acceptability of health care in MIMS and scarce use of acceptability metrics in policy design and health system evaluation. In the present study, we developed and empirically validated a theoretical framework for measuring users' acceptability of health care in a MIMS in the Caribbean. Using a minimum-data approach, we used a synoptic review of health-care literature and consultations with experts and health system stakeholders to define, scope and select constructs for the theoretical framework of health-care acceptability. Empirical validation of the modelled framework was performed using data collected from household expenditure and health-care utilization surveys in Carriacou and Petite Martinique (n = 226), island dependents of Grenada in the Caribbean. Data were used to create health utilization profiles and analyse measurement scales of the health-care acceptability framework using non-linear partial least square structural equation modelling. The modelled framework included 17 items integrating economic and psychosocial concepts, with 1 dependent construct (utilization) and 3 independent constructs (users' perception, experience and knowledge of health facility). Model analysis and validation indicated that the framework was significant, explaining 19% of the variation in health-care acceptability. Users' experience construct was influenced by perception and knowledge of health facility and was the only construct with a significant negative relationship with acceptability. Health-care acceptability declined with increased waiting and travel times and unsuitable opening hours. We conclude that acceptability comprises a complex multidimensional concept, which is highly dependent on various interacting variables and contextual characteristics of the health system. Therefore, policies and actions to improve acceptability should be context specific and focused on evaluating factors infringing health-care acceptability. Routine acceptability and/or satisfaction studies represent baseline evidence towards understanding and integrating acceptability in health-care assessment.

Driving factors influencing the rhizobacteriome community structure of plants adapted to multiple climatic stressors in edaphic savannas.

The natural variation of multiple abiotic stresses in hyper-seasonal edaphic savanna provides a unique opportunity to study the rhizobacteriome community structure of plants adapted to climate change-like conditions in the humid tropics. In this study, we evaluated changes in soil, plant and rhizobacteriome community structure parameters across seasons (wet and dry) in two edaphic savannas (SV-1 and SV-5) using four dominant plant species. We then examined relationships between rhizobacteriome community structure and soil properties, plant biomass, and conventional and novel root traits. We further hypothesized that plants adapted to the Aripo Savanna had a core rhizobacteriome, which was specific to plant species and related to root foraging traits. Our results showed that cation exchange capacity (CEC) and the concentration of micronutrients (Fe, Cu and B) were the only soil factors that differed across savanna and season, respectively. Plant biomass traits were generally higher in the dry season, with a higher allocation to root growth in SV-5. Root traits were more plastic in SV-5, and network length-distribution was the only root trait which showed a consistent pattern of lower values in the dry season for three of the dominant plant species. Rhizobacterial community compositions were dominated by Proteobacteria and Acidobacteria, as well as WPS-2, which is dominant in extreme environments. We identified a shared core rhizobacteriome across plant species and savannas. Cation exchange capacity was a major driver of rhizobacterial community assemblies across savannas. Savanna-specific drivers of rhizobacterial community assemblies included CEC and Fe for SV-1, and CEC, TDS, NH4+, NO3-, Mn, K, and network length-distribution for SV-5. Plant factors on the microbiome were minimal, and host selectivity was mediated by the seasonal changes. We conclude that edaphoclimatic factors (soil and season) are the key determinants influencing rhizobacteriome community structure in multiple stressed-environments, which are ecologically similar to the Aripo Savanna.